CA1319065C - Air-in-line detector for a medication infusion system - Google Patents

Air-in-line detector for a medication infusion system

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Publication number
CA1319065C
CA1319065C CA000584382A CA584382A CA1319065C CA 1319065 C CA1319065 C CA 1319065C CA 000584382 A CA000584382 A CA 000584382A CA 584382 A CA584382 A CA 584382A CA 1319065 C CA1319065 C CA 1319065C
Authority
CA
Canada
Prior art keywords
optical signal
wall
fluid channel
optical
lens member
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CA000584382A
Other languages
French (fr)
Inventor
Michi E. Garrison
John P. Pelmulder
Herman Lee Renger
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CareFusion 303 Inc
Original Assignee
Pacesetter Infusion Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pacesetter Infusion Ltd filed Critical Pacesetter Infusion Ltd
Application granted granted Critical
Publication of CA1319065C publication Critical patent/CA1319065C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61MDEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M5/00Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
    • A61M5/36Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests with means for eliminating or preventing injection or infusion of air into body
    • A61M5/365Air detectors
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84Systems specially adapted for particular applications
    • G01N21/85Investigating moving fluids or granular solids
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61MDEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2205/00General characteristics of the apparatus
    • A61M2205/12General characteristics of the apparatus with interchangeable cassettes forming partially or totally the fluid circuit
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S128/00Surgery
    • Y10S128/12Pressure infusion
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S128/00Surgery
    • Y10S128/13Infusion monitoring

Abstract

AIR-IN-LINE DETECTOR FOR A MEDICATION INJECTION SYSTEM
ABSTRACT OF THE DISCLOSURE
An air-in-line detection system for use in detecting air bubbles in the fluid line of a disposable cassette mounted on a main pump unit is disclosed which can accurately detect air bubbles in any type of fluid, whether clear or opaque. The system use an optical module mounted on the main pump unit to supply light and to detect light returned from the cassette, and an optical viewing are in the fluid flow path near the outlet end of the cassette. An inverted prism in the optical viewing path reflected light back to the the optical module when air is contained in the fluid flow path adjacent the optical viewing area, with the light not being returned if there are no air bubbles contained in the fluid flow path.

Description

P~ 3 IR-IN-LINE DETECTO~ FOR A ME~ICATION INFUSION SYS~EM

~pENTIFICATION OF RELATED ~TE~T ~PPLICATI~~
Thi6 application i~ related to ~ix ~ther currently filed Canadian copending patent ~pplications. ~hese patent applications are Serial No. 584,378, entitled "Disposable Cassette ~or a Medication Infu~ion Sy~tem", Serial No. 584,386 entitled ~'Piston Cap and Boot Seal for a Medication Infusion System'l, Serial No~ 584,377 entitled "Pressure Diaphragm for a Medication Infusion System"~ Serial No. 584,372 entitled "Ca~sette Optical Identification App~ratus for a ~edication Infusion System~, Serial No. 584,373 entitled" Ca~sette Loading and Latching Apparatus for a ~edication Infusion System" and Serial No. 5~4,38~ entitled l'Mechanical Drive System for a ~edication Infusion Sy6temn.

BACKGROUNp OF THE INVENTION
Fi~ld ~2~ the Invention - ~he present invention r~lates g~nex~lly to ~ ~y~tem ~or detecting the presence o~ ~ir in a flu~ , and more p~rticularly to a system ~or detecting an a~r b~bbl~ in the ~luld line on a d~sposable ca sette containing a ~luid pu~p therein, whic~ dispo abl3 cas~tte ~ 8 for in~tallation on~o and u~e w~th a ~ain pump unit, with an optical 6en~0r mounted in the main pump unit ~onitoring an optical ~5 ~iewing area in ~he fluid lin~ in the ca sstte to detect air, whether cont~ined in a clear fluid or in ~n opaqu~ fluid.
In ~he pa~t there have been two primary technigue~ which hava be~n used to deliver drugs which ~ay not be orally ~n~ested to a patient. The ~ir~t such technique i~ through an ~n~ection, 30 or ~hot, u~ing a 6yringe and needle which deliver~ a lxrge dosage at relati~ely infrequent intervals to th~ patient. This technique is no~ always ~atisfactory, particularly when th~ drug being administered lg poten~ially lethal, ha~ negative ~ide effect~ when delivered in a large dlo~ag~, or must be delivered mora or les& c~ntinuously to achieve the desired therapeutic effect. This problem results in smaller in~ections being yiven at more frequent intervals, a compromisa approach not yielding satisfactory results.
Alternatively, the second technique involve~ admini~tering a continuou~ ~low of medication to ths patient, typically through an lV bottle. Medication may also be delivered through an IV
system with an injection being made in~o a complex maze of IV
tubes, hose3, and other paraphernalia. With drop countex~ being used to meter the amount of bulk fluid delivered, many medication~ still end up bein~ administered in a lar~e dosag~
through an injection into the IV line~, although the medlcationY
may be diluted somewhat by the bulk fluid.
A5 an alternative to these two techniques o~ administering medication to a patient, thQ relakiYely recent addition of medication infusion pumps has come as a welcome improvement.
Medication infusion pumps are utilized to administer drugs to a patient in ~all, metered dose~ at fre~uent intervals or~
alternatively, in the case of some devices, at a low but essentially continuous rate. Infu~ion pump therapy may be electronically controlled to deliver preci~e, metered dose~ at exactly determined intervals, thereby providing a bene~icial gradual infusion o~ medication to the patient. In thi~ manner, the infusion pump is able to mimic the natural process whereby chemical balances are maintained more precisely by operating on a continuous time basis.
One of the requirements of a medication infu~ion system is dictatsd by the important design con~ideration of disposability.
Since tho portion of the device through which medication is pumped must be sterile, in mos~ appl~cations of modern medication infu~ion equipment some portions of the eguipment ars used only once and then disposed of, typically at regular in~ervals such as ono~ daily. It i3 therefore d~irabls that the ~luid pump portion of the in~usion pump device be di~posable, with thQ fluid pump b~ing designed a~ an attachable ca~stte which is of inexpensiv~ de~ign, and whlch i8 Qasily installabl~ onto th~ main pump unit~
It wlll ba perceived that it i~ deslrabl~ to h~ve a simple dispo~abl~ ca~sette de~ign to mlnimize the coElt o~ c:on~truction Or thQ ca~s~tte, u~ing the mlnimu3n nu~ber o~ part~ neaes~ary in the d~sign c: ~ the cassette. The de ign of tho casEsett~ mu~t be ma~ producible, and yet re~ult in a uni~or~ ~:a~ett~ which is cap~ble of deliver~ ng liguid Dl~dication or other ther~peutic ~luid~ with a high degre~ o~ ac~uracy. Th~ c2~ tte ~hould inGlude thQr~in mvrs than ~u~t a ~luid pump; othQr realtures whi~h havo i~orn~srly been included in peripharal device~ may b~ inc:luded 1~ in th~ aa6~gt~.
An e~sential ~Eunction oî a medic:ation infusion ~y~t~m i~ to avoid th~ inPuslon o~ ~luid containing air bubble~ therein.
Although ~t~p~ ~ay be tak~n to mini~iz~ the po~ibility o~ a~ r bub~ baing contained ln a ~luil d which ls to b0 in~used to a piat~nt, ~t 1~ ential to monitor this ~luid l~ne b~or~ it r~ach~a~ th~ pati~nt to ensure that ~ tan~ially no a~ r bubbles remain in t~ ~luid which i~ to b6l infus~d. The d~ec~ion of air bubblaa in all ~luid~; which are to be infused i3 th0refore a crit~cal ~les~gn requirement.
It i~ therefora the priraary ob~active of the present invention to provida an air-in ~ine detec~ion ~y~tem ~or u6e wi~h a di~posable cessse~te wh~ch i~ mounted onto a main pump unit.
Th~ ~y~tem oî the pr~o ent inven~lon mu~t be of a de~ign r2taining all o~ the advantage~ o~ infusion devices known in the p~st, and ~ust also provide a num~ter o~ additional advantage~ and improve,ments. Speci~ically, the air-in-line de~ection ~ystem o~
the present invention must be capable o~ detecting air bubbles in thet ~luid line o~ a disposablet cassett~ near the output end o~

1 31 qO65 th~ ca~ette, a~tar the pumping operation ha~ been per~ormed.
~he sy~tem ~ust bQ capable of accurately an~ e~ectively detecting air bubbles in any type of ~luid which may be in~used, whether the fluid i~ clear or opaque, a~ in the ca~e of lipid ~olutlons.
Several other addltional ~eature~ are de~irable in the design o~ a C~55Qtte and a main pump unik ~aking up an air~l~in-line dQtection sy~tem. Example~ o~ such ~eatur2s ara the ability to d~tect air bubble~ whether the flow rate o~ the ~lu~d in tha 0 c&g~ette i9 ~a~t or slow, and the ability to deteat air in the fluid line even when the interior o~ the fluid line remain~
coated with fluid. In addition to being able to detect air in the fluid line, the system must al~o be accurate, presenting a high degree o~ resista~ce to ~alse a~axms. No ca~sett~ in the art include~ an air-in-line detQ~tion syste~ which come~ clo e to combining thes0 features.
Despite th~ inclusion of all of the aforesaid feature~, the sy~tem o~ the pr~sent invention shall. utilize a minimum number of parts, all o~ which parts are o~ inexpen~ive construction, yet which af~ord tha assembled cass~tte the high degree o~ accuracy which must bQ retained. The RystQm of th~ pres~nt invention must also b~ o~ a design which enables ~t to compete econo~ically with known co~peting ~ystem~, and it must provide an aase o~ use rivaling the best of competing system~. Th~ system must accomplish all these objects in a manner which will retain and enhanca all of the advantages of reliability, ~urability, and safety of operation. The system of the present invention mus~
provids all of these advantages and overcome the limitatlons of the background art without incurring any relative disadvantage.
All the advantages of the present invention will result in a superior medication infusion system having a number of advantages making th~ system a highly desirable alternative to systems presently available.

~ - - ~ ~4_ 1 3 1 qO65 S ~ Y OF~THE INVENTION
The disadvan~ages and limitatlon~ of th~ background art discussed above are overcome by the present invention. Wikh this invention, a di~posabla cassette having only seven component~
thersin i~ ~e~cribed. The ca~etts utilize~ a highly accurate and raliable piston-type ~luid pump and an active valv~ de ign o~
unparalleled accurAcy, ~implicity, and accuracy Or operation. A
bub~le trap is included in the ca~sette ~or removing alr bubble~
introduced into the system, and a bubble datectoE i~ u~ed to ensure that fluid supplied to a patient iR virtually ~ubble-~rQe.
In the pre~erred embodiment o~ the present inventlon, the cassette includes an optical viewin~ area in the fluid ~low path near tha outlet line o~ the cassette, after the pump which i~
al80 contained in the di~po~abla cassett~. This optical viewing area in the cassette includes a lens which ~cts both a~ a ~ocu~ing elemant and ao a light directing element. Dep~nding on the ab~ance or presence o~ ~luid in thQ ~luid line adjac~nt ~he optical viewinq area, and also on the nature of the fluid contained in the ~luid line, the l~.ght directing element may allow ligh~ to pas~, or re~l~ct or dif~uRe light.
The main pump unit contains an o~tical module ha~ing a llght sourc~ and a ligh~ sensor. ~ight from the light souxce is directed onto the optical viewing area of the dispo~able ca~sette when the ca~ette is installed onto the main pump unit. In the praferred embodiment the light i~ re~lected b~ the light direoting element back onto the light ~ensor only when an air bubble i~ contained in the fluid line ad~acent the optical viewing area. When ~luid, either clear or opaque, i~ contained in the ~luid line adjacent khe optical viewing area, the light is not returned to the optical 6ensor. In the preferred embodiment, the light directing element i8 an inverted pri~ oparatiny in a "rever~e re~lected" configuration. Three alternata emhodiments are also dlsclo~ed, whi~h use di~fe:rent optical vlewing ar~a~ and d~erent optical path~.
It may there~ore be appreciated that the pre~ent invention provide~ an air-in--l.ine detection system for u~ with a dispo~able ca~ette which i~ mou~ted onto a m~in pump unit~ The systam o~ the present invention i~ of a d~ign re~aining all of the advan~age~ o~ infu~ion de~ice~ known in the past, and also provides a number of additional advantages and improvement~.
Speaifiaally, the air-in-line detsction system of the pre~ent invention i~ capable o~ detecting air bubbl~ in the ~luld line o~ a dieposable ca~sett2 near the output ~nd o~ the ca~tte, a~t~r the pumping operation ha~ bean performed. ~he ey~tem i~
al30 capable o~ accurataly and effectively detecting air bubbles in any type of fluid which may be infu~ed, whether the ~luid is clear or opaque.
Several other additlonal features are included in th2 design o the cas~ette ~nd the main pump unit making up the air-in-line detection sy~tem. Two o~ these features are the ability ko det~ct a~r bubbles whether the flow rate of the fluid in the ca~tte i8 fast or slow, and the ability to detect air in tha ~luid lin~ ~ven whan the interior o~ the fluid line rema~n~
coated with fluld. In addition to being abl~ to detact air in the fluid l$ne, the system is guite accurate, presenting a high degreQ of resi~tance to false alarms. No casset. Q in the art include3 an air-in~lins detection system which comes ~lose to the sy5t~m of the present invention.
Daspite the inclusion of all of the aforesaid feature~, the 5yst~m 0~ the present invention utilizes a minimum numb~r of parts, all of which parts are of inexpensiva construction, yet which afford the assembled cassette a high dagreQ o~ accuracy.
The system of the present invention is therefore of a design which enables it to compete aconomically with known competing systems, and it provide~ an ease o~ use rivaling the bast of 1 3 1 qO65 competing ~y8tem9. The system accomplishes all these ob~ects in a mann~r which retain~ and er~ances th~ a~vantages of reliability, durability, and s~fety of operation. Tha syst~m of the present invention provides these advantages and overcome the limitation~ of the background art without incurring any rela~ive disadvantag~ whatsoevQrO All the advantaga~ of the present invention re~ult in a superior med~cation in~usion system having a number o~ advantages which make the ~ystem a highly desirable alternative to systems presently available.
DESCRIPTION OF THE DRAWINGS
In the detailed descrlption of the pre~erred e~bodlm~nt a uniform directional sy~tem i5 us~d in which front, bac~, top, bo~tom, lefk, and right are indicated with respect to the op~rating position of the cassette and main pump unit when viewed ~rom th~ ~ront o~ the main pump unit. These and other advantage~
of the present inv~ntion are be~t undQrstood with ref~rence to the draw1ng~, in which :
FigurQ 1 is a top plan view of a disposable ca~ette body showing most o~ the fluid path through the cassette;
Fi~ur~ 2 is a ~ront side v~ew o~E tha ca~sette body shown in Figure l;
Figure 3 is a back side view of the cassett~ body shown in Figures 1 and 2;
25Figure 4 i8 a bottom ~iew o~ the cassette body shown in Figures 1 through 3;
Figure 5 is a right side view of the cassetts body shown in Figures 1 through 4;
Figur~ 6 i9 a le~t side view of the cassette body ~hown in Fi~ures 1 through 5;
Figure 7 is a partially cutaway vlew from the front side o~
the cassette body shown in Fi~ure~ 1 through 6, showing the ~ 3 1 '~65 bubblo trap UBed t:o remove air bubble~ ~rom the fluid supplied to the cassette: -Figur~ 8 is a partially cutaway view ~rom the right side O:ethe cas~ette body shown in Figures 1 through ~, ~howing the 5 cylindQr of the f luid pump contained in th~ ca~Bett2;
Figura 9 i3 a top plan view of a valv2 cliaphragm usQd to ~eal the pas~ageway~ on the top ~ur~ace of th~a cas~at~a body ~hown in Figure 1, tcs ~unction as the pres~ur~ diaphragm, and al80 to function as the valves ~or the pump;
10FiguPe 10 is a bottom view of the valve diaphragm shown in Figure 9;
Figur~ 11 is a cutaway view frc~m thQ back side o~ the valv~
diaphragm showr1 in Figures 9 and 10;
Figure 12 iB a cutaway view ~rom the ri.ght sid~ og the valve 15dlaphragm shown in Figures 9 and 10;
Figure 13 i8 a top plarl view o~ a valve diaphragm retainer u~ed to r~tain the valve diaphragm shown in Figur~s 9 through 12;
Figure 14 is a bottom view of the valve diaphragm retainer show2l in Figure~ 13;
20FigurQ 15 is a back side view of th~ valve diaphragm retainer ~hown in Flgures 13 and 14:
Figure 16 is a front ~ide view of the valve diaphragm retainer ~hown in Figures 13 through 15;
Figur~ 17 is a right side view of the valve diaphragm retainer shown in Figure~ 13 through 16;
Figur~ 1~ is a left side ~iew o~ the valvo diaphragm r~tainer ~hown in Figures 13 through 17;
F~gure 19 i~ a cutaway view from the front side of the valve diaphragm retainer shown in ~igure~ 13 through 18;
30Figure 20 is a cutaway Vi2W from the left side of the valve diaphragm retainer shown in Figure~ 13 through 19;
Figure 21 i5 a cutaway view from the right ~ide of the valve diaphragm retainer shown in Figures 13 through 20;

Figure 22 is a top view of a bubble chamber cap;
Figura 23 is a bottom view of the bubbl~ chamber cap shown in Figur~ 22;
Figure 24 i~ a le~t side vi~w o~ the bubbl~ cha~ber cap ~hown in Figures 22 and 23;
~ iyure 25 i5 a cutaway view from th~ back side o~ the bubble chambex cap shown in Figures 22 through 24;
Figuro 26 is a cutaway view from the right ~lde o~ the bubble chamber cap shown in Figures 22 through 24;
Figure 27 i~ a top plan view o~ a slid~ latch used both to lock the cas~0tke in place on a main pump unit, and to pinch o~f the IV outlet line prior to installation on the main pump unit;
Figure 2~ is a right ~ide view of the slida l~tch shown in Figure 27;
~igure 29 is a bot~om view o~ the slide latch sho~n in Figure~ 27 and 28, Figure 30 i~ a back lde vi~w of the slide latch shown in F~gur2s 27 through 29;
FigurQ 31 is a ~ront side view of the slide latch shown in Fiyure~ 27 through 30;
Figuro 32 is a cutaway view from th~ l~ft side of the slide latch showrl in Figures 27 through 31s Figure 33 is a side plan view of the piston cap and boot seal, which function both a~ a piston and as a bacterial seal;
Figure 34 is a top end view of the piston cap and boot seal shown in Figure 33;
Figure 35 is a bottom end view of the piston cap and boot seal shown in Figures 33 and 34;
Figure 36 is a cutaway view from the side of the piston cap and boot ~eal shown in Figures 33 through 35;
Figure 37 is a back sid~ plan view of a piston for insertion into the piston cap and boot seal shown in Figures 33 through 36;

~ g _ Figur~ 38 is a front side view o~ th2 piston shown in Figure 37;
Figure 39 is a top view of the piston shown in Figures 37 and 3 8:
Figure 40 is a le:~t side view of the piston shown ~n Figures 3 7 through 3 9;
Figure 41 i8 a bottom view of the piston shown in Figures 37 through 4 0:
Figure 42 is a cutaway view from the right ~ide of the piston shown in Figures 37 through 41;
Figura 43 i~ a top plan view of an assembled cas ett~ u~ing the component~ showrl in Figures 1 ~hrough 4~, with the s~ide latch in the closed position;
Figure 44 is a bottom view of the assembled cassette shown in Figure~ 43;
Figure 45 i8 a front sidQ view of the asse~nbled cassett:e ~hown in Figures 43 and 44;
Figure 46 i3 a back sida view of the assembled cassette shown in Figur~a~ 43 through 45;
FigurQ 47 is a le~t side view of the assembled eassette shown in Figures 4 3 1:hrough 4 6;
Figure 48 i8 a right side viaw o* tho assembled cas~ette shown in Figures 4 3 through 4 7:
Flgur~ 49 is a left side view of the latch head used to capture and actuate the piston;
Figura 50 is a right side view of the latch head shown in Figure 49;
Flgur~ 51 is a bottom view of the latch head showTI in Figures 49 an~ 50;
3 o Figure 52 is a top view of the latch head shown in Figures 4 9 ~hrough 5 1;
Figure 53 is a cutaway view from the right sid~ o~ the latch head shown in Figures 49 through S2;

Figura 54 i a right si~e view of ~he spring retainer to be mounted in the latch head shown in Figure~ 49 through 52;
Figure 55 i~ a front view of th~ spring r~tainer shown in Figure 5~a;
Figure 56 i a lef t side view of the latch ~ aw to be mounted on the latch head shown in Figures 4 9 through 52;
Figure 57 is a bottom view o~ the latch ~ aw 3ho~rn ln Figure 56;
Figure 58 is a back view o~ the latch ~ aw ~hown in Figure~
56 and 57;
Flgure 59 i~ a left slde view o~ the ~ aw~ a~sen~ly ~ n the open pos$tion, the jaws assembly being made up of the latch head shown in Figur2s 49 through 52, the spring ret~iner ~hown in Figure~ 54 and 55, ths latch ; aw shown in Figure~ 56 through 58, a latch spring, and pin~ used to assemble the various components tog~ther;
Figur~ 60 is a bottom view o~ the j aw~ assembly shown in FigurQ 59, wlth the ; aws assembly being shown in the open position;
Figure 61 i8 a left ~ide view of the jaws assembly shown in P'igures 59 and 60, with the jaws assembly baing shown in the clo6ed positlon (and in the open position in phantom line~;
Fi~ure 62 i5 a bottom plarl view of the main pump unit chassis;
Figure 63 is a front view of the main pump unit chassis shown in Figure 62;
Figure 64 is a top view of the main pump unit chassis shown in Figure~ 62 and 63;
Figure 55 i5 a back view of the main pump unit cha6si~3 shc~wn 3 o in Figures 62 through 64;
Figure 66 i~ a bottom plan view of the c:assette guide used to po~ition the cassette of Figures 43 through 48 on the main pump unit;

1 3 1 90~5 Figure 67 i5 a top vlew o~ the cassett guide ~hown in Figur~ 66 .
Figure 68 is a front view o~ the cassette guide shown ln Figures 66 and 67;
Figure 69 i~ a right ~id~ view o~ the cas~tt~ guide shown in Figur~EI 56 through 6B;
Figurç 70 i~ a left ~ide plan view of the pump shart on which i~ mounted the ~ aw~3 as~embly ~hown in Flgure~ 59 through 61:
F:Lgure 71 ls a right Bide ViQW plan view of the ~lide lock u~ad to rl3tain the caRsette shown in Figures 43 through 48 in po~ition on the main pu}np unit;
Figure 72 iB a bottom view oî the ~lide lock ~hown ln Figure 71;
F~ gure 73 is le~t ~ide view of tha slid~ lock ~hown in Figur~a~ 71 and 72, ~howing the beve:l used to reflect the light b~a~ from the optical light source away ~rom the optlcal light sensor when the slide loc:k i8 in the open position;
Figure 74 is a top view v~ the slidQ losk shown in Figures 71 through 73, ~howing the reflQcti~e surface used to reflect the light beam ~rom th~ opl:ical light ~;ource to the optical light ~en~or when t~ slide lock i~ in ths closed position;
Figure 75 i~ a front ~ide view o~ the ~lide lock shown in Figures 71 through 74;
Flgure 76 i~ a back ~ide view o~ the slide lock shown in Figures 71 through 75, showing the Rlanted surface used to re~lect the light beam away from the corre~ponding sensor when the slldo loak is in the op~n position;
Figure 77 is a side view of the power module cam used both to drive the pump through the pump shaft ~hown in Figuro 70 and to drivs the valve actuators;
Figure 78 is a side view o~ the power modul~ cam rotated ninety degree~ from the view of Figure 77;

131qO65 Figure 79 is a bottom vi~w of the powsr module cam shown in Figure~ 77 and 78;
Flgure 80 i8 a chart of th~ inlet and outlat valve positions and th~ pump displacement versus angular position o~ the power modulQ cam shown in Figure~ 77 through 79;
Figure 81 i~ a plan view from the front ~ide of the dxive assembly including the motor/cam mount, the motor, the power modul~ cam shown in Figuras 77 through 79, and the po~ition encod~r as embly;
FigurQ 82 is a top view sf the motor/cam mount ineluded in the drive as~embly shown in ~igure 81;
Figure 83 is a top view of one o~ the actuator guid~s used to guida and retain in position the valve actuator~ ~or one cassette:
Figure 84 ic a ~ide view o~ the actuator guide shown in Figure 83;
Figure 85 is a ~ida plan view of a valve actuator;
Figure 86 is an side edge view of the valve actuator shown in Figure 85;
Figur~ 87 is a bottum view of thQ val~e a~tuator ~hown in Figur~3 85 and ~6;
~igure 88. i3 a top plan view o~ a pre~sure tran~ducer;
Figure 8g is a side view of the presRure transduc~r ~hown in Figure 88:
Figure 90 i~ a bottom view o~ the pre~sure tran~ducer shown in Figures 88 and 89:
Figure 91 is a front plan view of an optical ~ensor module;
Figure 92 îs a side view of tha optical ~nsor module ~hown in Figllre 3~;
Figure 93 is top view o~ the optical sansor modula shown in Figures 91 and 92;

1 3 1 qO65 Figure 94 i~ a bottom view o~ the optical sensor module shown in Figure~- 91 through 93 showing the opkical source and ~ensor pair for detecting the closed po~ition of the ~lide lock;
Figure 95 i~ a ~irst cutaway view o~ tha optical sen~or module shown in Figure~ 91 through 94 showing the optical sources for d~tecting the cassette identification bit~;
Figure 96 i~ a second cutaway view of th~ optical sen~or module ahown ln Figure~ 91 through 94 ~howing the optical 3en~0rs for detecting the cassette identification bits, and the optical sourc~ and sensor pair for detecting air bubble~ in th~ fluid linQ;
Flgure 97 is a bottom plan view of the ~la3tomeric valve actuator seal u~ed to bia~ the valve actuator~ in an upward position:
Figur~ 98 i~ a cutaway view o~ the valve actuator ~eal shown in Figure 97;
Figure 99 is a bottom view o~ the main pump unit chassie having the variou~ components for one. pump mounted t~ereon, with tha slide lock in th~ open position ready to receive a cassette;
Figur~ 100 ls a bottom view o~ the main pump unit chassiR
shown in Figure 99, with the ~lide lock in the closed pos$tion a~
it would be i~ a cassette were installed and latched onto the main pump unit;
Figure 101 iB a top view o~ the cassette shown in Figures 43 through 49 in the installed position relative to the optical sensor module, with all other parts removed for clarity;
Figura 102 is a side view of the cassette and opkical ~ensor module of Figure lOls Figure 103 i~ a firs~ cutaway view o~ ~he cassette and the optical ~en~or module of Figures 101 and 102, showing a ca~sstte identi~ying indicia having a logical zero value;

Figure 104 is a second autaway view of tha cas~ette and the op~ical ~ensor module of Figures 101 and 102, showing a ca~ette identifying indicia having a logical one value;
Figure ln5 i~ a cutaway view from Figura 99 ~howing the slid6 lock in th~ open position over thQ cassQtta-in-place sensor o~ khQ optical sensor module:
~ igure 106 is a cukaway view from Figura 105 showing how the slanted aur~ace reflects the light beam away fro~ thQ cas~ette-in-place ~nsor;
10Figure 107 is a cutaway view from Figure 100 showing the ~lide lock in the closed position over the cas~ttQ-in-place ~en~or o~ th~ optical ~en~or module, with the light beam b~ing r~flected back onto the ca~sette-in-plac~ ~enYor;
Figure 108 is a third cutaway view of the ca~sette and the 15optical ~ensor module of Figur~ 101 and 102, showing the air-in-line datection apparatus o~ the pre~err~d embodiment:
Figure 109 i~ a cutaway view like Figure 108, but ~howing a first alternate air-in-line detection apparatus;
Figure 110 i~ a cutaway view li]ce Figure 10~, but showing a ~econd alt~rnate air-in-line detection apparatus~
Figure 111 is a cutaway view like Figur~ 108, but showing a third alternate a~r-in-llne de~sction apparatu~;
Figure 112 is a cutaway vlew ~rom the side o~ the main pump unit cha~si~ having the various components for one pump mounted thereon and a cassette installed, showing the pump drive train;
Figure 113 is a sectional YieW of the pump and valve~
showin~ the baginning of the fill cycle;
Figure 114 i5 a sectional view of the Pum~ and valves showing the beginning of the pump cycle:
30Figure 115 is a sectional view of the pressure plateau, the pressure diaphragm, and the pressure transducer; and 131{~065 Figure 116 i a second sectional view of the pressure plateau, tha pressure diaphragm, and the pressure transducer shown in Figure 115.

DETAILED_DESCRIPTION OF THE PREFERRED EMBOD~NT
he Cassette- ~ha pre~erred sm~70dim~nt of the cas~ette uslng thQ air in-line detector o~ the preeent invention includes all o~ the ~eaturQs described abov~ in a single ~ompact di~posable cassette constructed of seven part~. Prior to a d~scu~on of the constructlon and operation ~f the cassQtte, ~he ba~ic construction o~ which is the ~ub~ect o~ tha above-identified patent appllcation entitled l'Disposable Ca~sett~ ~or a ~edication Infusion Sy~tem,~ it i8 advantageous to di~cuss the con~ruc~ion and configuration o~ the seven components included in th@ ca~sette. The ~ir~t of thesa components and the one around which the other six components are a~sembled is a cassette body 100, which i~ shown in Figures 1 through 8. The cassette body 100 has an upper surface portion 102 which is es~entially ~lat with a number o~ protrusions and indentations located in the top sur~ace thereo~ tFigure 1). The upper surface portion 102 ha~ ~ hicknes~ sufficient to acaommodate the indentations m~nt~oned above, ~ome of which are fluid passageways which will be discu.~sed below.
Re~errlng generally to Figures 1 through 8, a bubble trap 104 is located at the front right sorn~r o~ the cas~ette body 100 below the upper surface portion 102, which bubble trap 104 is es~entially square in cross-section (F~gure 4). The bubble trap 104 includes therein a bubble chamber 106 which i5 open at the bottom thereo~ (Figure~ 4, 7, and 8) and closed at the top by the bottom of the upper ~urface portion 102 o~ the ca~sette hody 100.

A siphon tube 108 is located in the bubble chamber 106, and the siphon tubs 108 has an aperture 110 therein leading from the 1 ~ 1 9065 bottom of the bubble chamber 106 to the top of the upper surface portion 102 of the cassette body 100.
Locatad behind the bubble trap 104 below tha upper sur~ace portion 102 o~ the cassette body 100 on the right side thereo~ i5 a pump cylinder 112 (Figure 3-5, 3). ~he pump cylinder 112 does not extend downward as far as does the bubbl~ trap 104~ The pump cylindQr 112 is open on the bottom therao~, and is arranged and configured to receive a piston which will be di~cussed below.
The inner configuration of the pump cylinder 112 has a main diameter bore 114, with a greater diameter bore 116 ~ear thQ
bottom o~ the pump cylinder 112. Th~ interior o~ the bottom of thQ pump cylinder 112 below the greater diametQx borQ 116 a~ well as ths area im~ediately between the great~r diameter bcre 116 and the main diameter bore 114 are tapered to facilitat~ entry o~ the pi ~on. The main diameter bor~ 114 terminate~ at the top thereof in a frustroconical smaller diameter aperture 118 leadin~ to ~ha top o~ th~ up~er 6urface portion 102 of the cassette body 100 (Figure 1). The smaller diameter aperture 11~3 is tapered, havinq a smaller diam~tex at tha top thereof than at the bottom.
Extanding from on the back ~ide o~ the exterior of the bubble trap 104 facing the pump cylinder 112 ara two piston r~taining flngers 120 and 122 (Figures 3 and ~) de~ining 810t3 therein. The slots defined by the two piston retaining ~ingers 120 and 122 ~ace each other, and are open at the bottom~ thereof to accept in a sliding fashion a flat sag~ent fitting between the two pi~ton rataining fingers 120 and 122. Tha two piston retaining ~inyers 120 and 122 extend from the lower surfac~ of the upper surface portion 102 of the cas~ette body 100 to a location b~tween the bottom of the pump cylinder 112 and the bottom of the bubble trap 104.
Al~o extending from the bottom side of tha upper surface portion 102 of the cassette body 100 are two latch supporting fingars 124 and 12~ tFigures 1 4 and 7). The la~ch supportiny Pinger 124 extends downwardly from t:he left sida of ~he bottom o~
the upper surface portion 102 of the cassette body 100, and at the bottom extends toward the right slightly to ~orm an L shape in cro~s section. The latch supporting finger 124 extand~ toward the front of tha cassette body lOo further than ~does th~ upper surfac~ portion 102 of the cassette body 100 (Figure 1), and tsrminate~ approximately two-thlrds o~ the toward the ba~k o~ the upper eurfac~ portion 102 of the cassette body 100.
The latch supporting finger 126 extands downwardly ~ro~ the bottom o~ th~ upper surface portion 102 o~ the cassatte body loO
at with th~ left side of the bubble trap 104 ~orming a portion of the latch supporting finger 126. The latch supporting ~inger 126 extend3 toward the left ~lightly at the bottom thereof to form a backwards L-shape in cross section. The latch supporting finger 126 parallels the latch supporting finger 124, and i~ equally deep (Figure 4). ~he latch supporting fingers 124 and 126 together will hold the slide latch, to be described below.
Tho pas~ageway~ located in the top of the upper surface portion 102 o~ the cassette body lOo may now be dsscribed with primary re~erence to Figure 1. The pa~sageways in the top of the upper surPace portion 102 are all open on the top side of the upp~r surfaca portion 102, and are generally U-shaped as they are recessed into the top of the upper surface portion 102. A first passageway 128 communicates with the aperture 110 in the siphon tube 108 of th~ bubble trap 104 at on~ end thereo~, and extends toward the back of the upper surface portion 102 of th2 cassette body lOo to a location to the right of the smaller diam~ter aperture 118 of the pump cylinder 112.
A cylindrical pressure plateau 130 which i~ e-~sentially circular a~ viewed from the top extends above the upper ~urface portion 102 of the cassette body 100 slightly left of the center thareof (best shown in Figures 1 through 3, also shown in Figures 5 through 8). The top of the pressure pla~eau 130 is flat, with a channel 132 ~xtending across the flat top of khe pressure plateau 130. The channel 132 extencls from five o'clock to elevsn o'clock as vlewed from the top in Figure 1, with the back of the ca~sette body 100 being twelve o'clock. ~he channel 132 i8 also shown in cro~-section in Figuro 115, and in a cutaway vi~w in Figure 1~6. Tha depth of the channel 132 in th~ sur~ace o~ th~
pressurQ plateau 130 is not quit~ the hei~ht of the pres~ure plat~au 130 above the upper sur~ace portion 102 of the cassette body 100, with the channel 132 gradu~lly be~oming deeper with a 1~ s~soth tran~ition at the ed~e~ o~ the pr8~Ure plateau 130 to extend into the upper sur~ace portion 102 o~ the cass~tt~ body 100 (Fiyure 116).
A ~econd passageway 134 in the top of the upper surface portion 102 ~ the cassettQ body 100 begins at a location to the le~t of the smaller diameter aperture 118 of the pump cylinder 112, and extands toward the front o~ the upper surface portion 102 approxima~ely abo~e th~ latch ~upporting finger 126. The saoond passag2way 134 then travels tv the left to connect in fluid co~munication with the end of the channel 132 in th~
pressura platsau 130 located at fi~e o'clock. A third passageway 13S in th~ ~op o~ tha uppar sur~acQ portion 102 of the cassette body 100 begin~ at the end of the channel 132 in the pressure plateau 130 located at el~ven o'clock, and moves toward tha back and l~ft of the ca~sette body 100.
At the end o~ the third passageway 136 i~ a recessed lens portion 138, which recessed lens portion is used to focus and reflect liyht used to detect air bubbles passing in ~ront of the rec~ssed len~ portion 13B. The recessed lens portion 138 i8 also recesaed into the top of th2 upper sur~ace portion 102 of the cas6ette body 100 to allow fluid to pas~ therethrough. The recessed len~ portion 13~ is part o~ the apparatus which i8 the sub~ec~ o~ the present invention. A ~ourth passageway 140 in the top of the upper surface portion 102 of the cassette body 100 ~ 19--begins at the other side o~ the recessed len3 portion 138 from the third pa~sag~way 136, and ~xtend~ ~rom the le~t and back of the ca~sette body 100 toward the front and righk o~ tha cassette body 100 around thQ pressure plateau 130 to a location at approximately seven o'clock on the pressure plateau 130. It shoul~ be noted that the fourth passageway 140 i8 spaced away rrom ths pr~ssure plateau 130 to allow ~or ~ealing neans therebetween.
The end of the fourth passageway 140 terminate~ at thQ
1~ location at seven o'clock to th~ pre~ure plateau 130 in an apsrture 142 extending through the upper ~ur~ace porkion 102 of the ca~sette body 100 ~Figura 1). Locat~d underneath th~ upper sur~ac~ portion 102 o~ the cassetta body 100 concentrically around the aperture 142 is an the outlet tube mountlng cylinder 144 (Fi~ure3 3 and 4) which i5 in fluid communication with the aperture 142. The outlet tube mounting cylinder 144 extends downwardly from the bottom of the upper ~urfac~ portion 102 of the ca~set~e body 100 to a location above the portions of the latch ~upport~ng finger 124 and the latch supporting finger 126 extending parallel to the upper surface 102 o~ the cassette body 100. A upport fin 145 ex~end~ to th~ right from the ~ront o~
th~ outlet tube mounting cylinder 144.
Located on top of the upper ~urface 102 of th~ cassette body 100 i6 a alightly raised border 146 (Figure 1) which completely surrounds the first passageway 123, the smaller diameter aperture 118, the second passageway 134, the pr~ssur~ plateau 130, the third passageway 136, the recessed lens portio~ 138, the recessed len~ port$on 138, and the ~ourth pa~sagQway 140. The slightly raised border 146, which is used ~or sealing purposes, closely surrounds the edges of all of the afore-mentioned segments of the cassette body 100, except as ~ollows. The slightly raised border 146 is spacad away from the portions o~ the ~irst pa~sageway 128 1~19065 and the second pa~sageway 134 ad-~acent tha smaller diameter ap~rture 118, and the smaller diamQter aperture 118.
The portion~ o~ the sllghtly rai~ed border 146 around the small~r diamet~r aperture 118 resembles a rsctangle with its wider ~lde~ located to the front and back and spaced away from the valv~ diaphr~m 170, and it~ narrow0r ~ide3 to the right o~
the portion o~ the fir~t pas~ageway 12~ ad~acent the smaller diamet~r aperture 118 and to thQ l~ft o~ the portion o~ the second pas~ageway 134 ad~acent the smaller diameter apertur~ 118.
~h~ rectangle i5 broken only at the locationa th~ ~irst - pa~ag~way 128 and the eecond passageway 134 extend towards the front o~ th3 cas~ette body 100.
The sliyhtly rai~ed border 146 has a segment 147 locat~d betweon the portion of the first pas~ageway 128 ad~acent the ~m~ r diameter aperture 118 and the ~maller diameter ~parture 118 it881~, with th~ ~egment 147 extending betw~en the two wider ~ides o~ the rectangle. The slightly raised border 146 al80 has anoth~r ~Qgmenk 1~9 locatad between the portion of th2 second passag~way 134 ad~acent tha smallar diameter ap~rture 118 and the 20 3~aller diameter aperture 118 its~lf, with thQ segment 149 e~tending bQtwe~n the two wider sldes o~ the recta~gle. The slightly rai~ed b~rder 146 is also spaced away from the sides of the pressure plateau 130, and th~ portions o~ the second passageway 134 and the third passageway 136 immediately ad~acent the pressur~ plateau 130.
Located at the back of the upper surface 102 of the cassette body 100 are three cassette identifying indicia 148, 150, and 152. The first and third cassette iden~ifYin~ indicia 1~8 and 152 are small, solid cylinders extending upward from ths top of 30 tha upper ~urface 102 of the cassette body 100 (Figures 1 and 3).
The second caseette identi~ying indicia ~50 is a prism cut into the bottom of the upper surfacs 102 of ~he cas~atte body 100 (Figure 4). The first, second, and third cassettQ identifying 1 ~ 1 9065 indicia 148, 150, and 152 are the sub~ect of ths above-identified patent application entitled "Cassette Optical Identi~ication Apparatu~ for a Medication Infusion System.~ It will be noted that the cassette identifying indicia 148, 150, and 152 may be in any order or configuration, and are used for di~ferent ID codes to identi~y up to eight di~ferent ca~settes. Addi~ional ID bits could al50 be used if more than eight dif~2rent ca~etta~ are us~d. If redundant codes ara deslred, the thre~ bits would o~
cour~ accommodate the use of less th~n ~ight di~erent cas~ettes.
Compl~ting the con~truction o~ the cas~ettQ body 100 ~re fiVQ hollow cylinder~ 154, 156/ 158, 160 and 162 protruding ~ro~
the top ~urface of the upper surface 102 of the cassette body 100, an aperture 161 and a slot 164 located in thQ top surface o~
the upp~r aur~ace 102 of ths cas~ette body 100, and a slot 166 located in tha top surface of the latch supporting finger 124.
Four of the hollow cylindars 154, lS6, 158, and 160 are located around the pressur~ plateau 130, with the fifth hollow cylinder 162 being located to the left of the aperture 110 over the bubbla trap 104. The aperture 161 is located in the top surface vf the upper sur~ac~ 102 of the ca~e~te body 100 in front and to the right o~ center of the pressure plateau 130. The 810t 164 iS
located in the top surface of the upper sur~ace 102 of the cassette body 100 near the back and ~he right side thereof. The slot 166 i~ located in the ~op surface of the latch supporting finger 124 near the front of the cassette body 100.
Referring now to Figures 9 through 12, a valve diaphragm 170 ls shown which is arranged and configured to fit ovar the top of the upper ~urface 102 of the cassette body 100 (Figure 1). The valve diaphragm 170 is made of flexible, resilient matarial, such as a ~edical grade silicone rubber. The hardne6~ o~ the material used for the valve diaphragm 170 would bs batween thirty and fifty on the 5hore A scale, with the pre~err~d embodiment 1 ~ 1 qO65 utilizing a hardness of approximately thirty-five. ~he valve diaphragm 170 ha three primary funations, the fir~t of which is to seal tha tops of th~ first, second, third, and Pourth passageways 128, 134, 136, and 140, re~pectively. Accordingly, the main sur~ace of the valva diaphragm 170 is flat, and i~ sized to ~it over the first, second, third, and fourth passageways 128, 134, 136, and 140, respectively, and also over the ~ntire slightly raised border 146. Th~ flat portion of the valve diaphragm 170 ha~ three aperture~ 172, 174, and 176, and a notch 175 therein to accommodate the hollow cylinders 156, 160, and 162 and a pin ~itting into the aperture 161 (Figure 1), re~pectively, and to al ign the valve diaphragm 170 in position over the top of the upper sur~ace 102 of the cassett~ body 100~ It should be noted that the valve diaphragm 170 doe~ not necessarily ~urround the other two hollow cylinders 15~ an~ 158.
The second primary ~unct~on o~ the valve diaphrag~ 170 i5 to provide both an inlet valv~ batween t:he first passageway 128 and th~ smaller diamQ~er apertur~ 118 le~ading to the pump cylinder 112, and to provide an outlet valve between the ~maller diameter aperture 118 leading to the pump cylinder 112 and khe second pa~sageway 134. To ~ul~ill this funation the valve diaphragm 170 has an essentially rectangular domed portion 178 (shown in plan view in Figures 9 and 10, and in cross-sectional views in Figures 11 and 12) forming a cavity 180 in the bottom of the valve diaphragm 170. When the valve diaphragm 170 is installed in position o~ the top of the upper surface 102 of the cassette body 100, the cavity 180 will be located just inside the rectangular portion of the slightly raised border 146 around the smaller diameter aperture 118 leading to the pump cylinder 112 (Figure 1).
The cavity 180 will there~ore be in fluid communication with the first passageway 128, the smaller diameter aperture 118 leading to the pump cylinder 112, and the second passageway 134.

Prior to in6tallation of the casisette onto the main pump unit, thQ cavity 180 a-llow~ the open ~luid path to ~acil itate priming o~ the ~ass~tte, where all air is removed from the ~ystQm. Once pr~ mi~d, the casisette may b~ inserted onto the main pump unit and 5 the cavi~y 180 will contact valve actu~tor~ to prevent Iree flow through th0 cas3ette. By uising an inlet valv~3 actuator to forca th~ do~ed portion 178 over th2 segm~nt 147 o~ the ~ightly raised border 146 (Figure 1), th~ îlow o~ fluid~ b~stwQen ~he ~irst passagi3way 128 and the ~maller diam2ter ap~arturi~ will ba 10 blocked, but the flow oP ~luids b~twe~n th~ ~maller diameter apartur~ 118 and th~3 s~cond pa~sag~way 134 will ba unafr~cted.
.3 ~I Lik~wise, by u~ing an outl~3t valv~ actuator to ~orca the domed poxtion 178 over the se!gmQnt 149 o~ lightly r~ d bordQr - 146 (Figur~ 1), the ~low oî fluid~ betwe~3n th~ ~mall2r dl~meter ap~rture 118 and tha ~econd pa~Rageway 134 will be blocked, but tho ~low o~ fluid~ b~tween the fir~t pas~ageway 128 and the ...
~maller dia~et~r apertur~ 118 will be una~ected. Extending around and 3pacad away from th~ rrOnt and side~ o~ the dom~d portion 178 on th~ top ~ur~ac~ of the valve diaphr~gm 170 1~ ~ U
.E~
~ 2g shap~d rais~d r~b 181, the legs Or which ~xtend to th~ back of ~ the valve diaphrag~ 170 (Flgure 9)J
.~4 i~ ~h~ th~rd pr~ary ~unction o~ ths valvo diaphragffl 170 i~ to -~ provide a pr~sure diaphragm which may b~ u~ed to ~onitor outlet ~luid pressure. A~cordingly9 the val~e diaphrag~ 170 has a pre~5ur~ ~iaphragm 182 which i~ supported atop an upper cyli~drical 6egme~t 184, which in turn i8 located atop a lower cylindrical seg~en~ ~6 ex~ending above ~he sur~aco o~ the valve diaphragm 170. Th~ upper cylindrical segment 184 and the lower cylindrical ~egment 186 have identical inner diameters, with a lower cylindrical segment 186 having ~ greater outer diameter than the upper cylindrical segment 184. A portion of the top o~
the lower cylindrical ~e~ment 186 ~xtends ou~wardly around the bottom of the upper cylindrical segment 184, creating a lip 1R8.

~ 2~

In the preferred embodiment, the pr~sure diaphragm 182 may be domed slightly; as seen in Figure 11.
Turning now to Figure3 13 through 23, a retainer cap 190 is shown which fits over the valve diaphragm 170 after it i~ mounted on the top o~ the upper ~urface 102 of the cassetts body 100.
The retainer cap 190 thu~ function~ to cover th~ top o~ the cassette body lOo, rataining the valve diaphragm 170 batwQen the retainer cap 190 and the cassetta body 100 in a saaling fashion.
The retainer cap 190 thu~ has the same general outline when view~d from the top (Figure 13) as the cas~ette body 100 (Figure 1). Located in the bottom o~ the ratainer cap 190 (Figure 14) are ~ix pin~ 192, 194, 196, 198, 200, and 199, which are to be recQiYQd by the hollow cylinders 154, 156, 158, 160, and 162 and the apertur~ 161, respectively, in the casBette body 100 to align tho ratainor cap 190 on the cassette body lOQ. Al60 located in the bo~tom Or the re~ainer cap 190 i3 a tab 202 to be received by the 813t 164, and a tab 204 to be rec~aived by tha ~lot 166.
The r~ainer cap 190 ha~ three apertures 206, ~0~, and 210 therethrough loca~ed to coincide with th~ location~ of the fir~t ca~sette identifying indicia 148, the s~cond cassette identifyin~
indicia 150, and tha third cassette identifying indiaia 152, rQspectiv~ly. The ~$ze o~ the three aperture~ 206, 208, and 210 is sufficient to receive the small, olid cylinders which the first cassette identifying indicia 148 and the third cassette identi~ying i~dicia 152 comprise.
Located in the retainer cap 190 is a rectangular aperture 212 (Figure~ 13, 14, 19 and 20) for placement over the domed portion 178 on the valve diaphragm 170. The rectangular aperture 212 ln the retainer cap 190 is slightly larger than the domed portion 178 or~ the valve diaphragm 170 to prevent any closure of the cavity 180 formed by the domed portion 17~ when the retainer cap 190 is placed over the va~ve diaphragm 170 and khe cassette body 100. ~he domed portion 178 of the valve diaphragm 170 kharefore will protrude throu~h ths rectangular aperturQ 212 in the r~tainer cap 190. In the bottom o~ the retainer cap 190 around the rectangular aperture 212 i5 a U~shaped groova 214 (Figure 14) designed to acco~odate the U-shaped raised rib 181 on the valve diaphragm 170.
Al~o located in the retainer cap 190 i8 a circular aperture 216 (Figure~ 13 and 14), which has a diameter ellghtly larger than the outer diameter of tha upper cylindrical segment 184 on the valve diaphragm 170, to allow ths upper cylindrical segment 10184 ~nd the pressure diaphra~m 182 to protrud~ ~rom the circular - a~erture 216 in the retainer cap 190. The diameter oR the cir~ular aperkure 216 is Rmaller than the outer diameter of the lower cylindrical segment 186 on 170, and on the bottom of the rQtainer cap 190 i3 disposed concantrically around the circular 15apertur~ 216 a cylindrical recess 218 to rec~ive the lower cylindrical ssgment 186 on the valve diaphrag~ 170. Disposed in the cylindrical recess 218 on the bottom side of the retainer cap 190 i~ a circular raised bead 220 ~Figuras 14, 19, and 21) to h~lp in thG ~ealing of the cassette as it is assembled.
20Th~ retainer cap 190 ha~ a front edge 222 (Figure 16), a back edge 224 (Figure 15~, and left ~Figure 18) and right (Figure 17) sid~ edges 226 and 228, respectively. Th~ ed~e3 222, 224, 226, and 228 will contact the top of the upper sur~ace 102 of the ca88ette body 100 when the retainer cap 190 is assembled onto the 2ca~sette body 100 with the valve diaphragm 170 disposed therebetween. The retainer cap 190 is attached to the cassette body 100 in the preferred embodiment by ultrasonic welding, but adhesives or other bonding technique~ known in the art may also be used.
30Referring next to Figure~ 22 through 26, a bubble chamber cap 230 is illustrated which i8 for placement onto the open bottom o~ the bubble trap 104 (Figure 4). The bubbla chamber cap 230 is on the bottom (Figure 23) the same ~ize as the outer edges ~ 3 1 9065 of the bottom of the bubble trap 104 (Figure 4), and ha3 a tab 232 ~Figure~ 22 through 24) on the bottom which will project toward tha back o~ the cassette beyond the back edge o~ the bubble trap 104. The bubbla chamber cap 230 has a rsctangular wall portion 234 (Figur- 24) extending upward from the bottom of the bubble chamber cap 230 and de~ining th~rein a ~quare space, which rect~ngular wall portion 234 i9 ~ized to rit in~ida ~hs bubble chamber 106 (Figure 4).
Loa ~d at the front and l~ft ~ide~ o~ the reatangular wall lo portion 234 and extending upward3 ~rom tha botto~ o~ the bubbla chamber cap 230 is an ~nl~t cylinder 236 (Figures 22, 24, and 26) hav~ng an inlet aperture 238 extendiny therethrough. The inlet aperture 238 extends through the bottom o~ the bubble chamber cap 230 (Figures 23 and 25), and is design~d to receive from the botto~ o~ thQ bubble chamber cap 230 a lsngth of tubing therein.
The bubbl~ ~hamber cap 230 i~ attache~ to tha bottom of th~
bubbl~ trap 104 in the cassett~ body lQo in the pre~erred embo8iment by ultrason.ic welding, but. adhesives or other bonding ~echnigu~ known in the art may also be used.
When th~ bubble cha~ber cap 23D is mounted to the bubble trap 104, the inlet cylinder 236 extends up to at least half o~
t~ h~ght o~ ~he bubble cham~ex 106 (Figure 7), and the ~iphon tube 108 (Figur~ 7) draws fluid from th~ bottom o~ the siphon ~ub~ 10~ in the space within the rectangular w~ll portion 234 o~
tha bubble ehamber cap 230 (Figura 26). It will ba appreciated by those skilled in the art that fluid will enter the bubble chamber 106 through the inlet aperture 238 in the inlet cylinder 236 near the top of the siphon tube 108, maintaining all air bubble~ abova the level near the bottom of the bubble chamber 106 at which fluid is drawn from the bubble chamber 106 by the siphon tube 108.
Moving now to Figures ~7 ~hrough 32, a slide latch 2~0 is disclosed which served two main functions in the cassette. The ~ 3 1 9065 slide latch 240 first serYes to latch the cassette into place in a main pump unl~. It al~o ~erve~ to blocX the f~ow of flu~d through th~ cassetta when it is not installed, with the closing of the slide latch 24n to lock the cas~ette into place on the main pump unit al90 simultaneou~ly allowing th~ flow of fluid through the cassette. The slide latch 240 slides ~rom the front Or tho ca3sette body 100 (Figure 2) between the latch ~upporting finger 124 and the latch supporting fin~er 126.
The slide latch 240 has an esssntially rectangular, flat front portion 242 (Figure 31) which ig of a height e~ual to the hoight Or the cassette body 100 with ths r~tain0r cap 190 and the bubble chamber cap 230 ins~alled, and a width a~ual to the distanc~ between tha left side o~ th~ bubble trap 104 and the left sidQ o~ tha cassette body 100. Two small notches 244 and 246 are removed from th2 bacX ~ide of th~ front portion 242 at khe top thereof (F~gures 27, 28, and 30~, the ~mall notch 244 being removad at a location near the left corner, and th2 small notch 246 b~ing removed at tho right cor~er.
Extending Prom thQ back side of the ~ront portion 242 about three-quarter~ o~ the way down towards the back is a horizontal bottom portion 248 ~Figur~ 29), which has it~ adge~ directly below the closest adges of the small notch 244 and the small notch 246, Extendin~ from ths inner edge o~ the small notch 244 at the top of tha slidz latch 240 down to the bottom portlon 248 i8 an inverted angled or L-shaped portion 250. Similarly, extending from the inner edge o~ the small notch 246 at the top of the ~lide latch 240 down to the bottom portion 248 i~ an inv~rted, backwards angled or L-shaped port~on 252 (Figure~ 27 and 28).
Spaced outwardly from the left side o~ the bottom portion 248 and the le~ si~e of the leg of tha inverted L-shaped portion 250 is a left slide ~ide 254. Likewise, spaced outwardly from the right side of the bottom portion 248 and the righk side of the leg of- the invarted, backwardE~ ~-shaped portion 252 i~ a right slide side 256 (Figures 28 and 30~. Th~ left and right 51ide sides 254 and 256 are located slightly above the bottom of th~ bottom portion 248 (Figura 30). Th~ la~t and right slid~
s ~id~ 254 and 256 are o~ a height to be engaged in the latch suppor~ing finger 124 and the latch ~upporting fingar 126 ~Figure 2), re~pectivaly.
~ ocatQd in th~ bottom portion a48 i~ an elongat~d, tear-shap~d aperture 258 (Figure 29), with th~ wider portion thereo~
toward tha ~ront of the slide latch 240 and th~ extended narrower portion thereof toward the back of the slide latch 240. When the ~lid~ latch 240 is inserted into the latch supporting ~inger 124 and the latch supporting finger 126 on thQ cas~ette body 100, and the ~lide latch 240 i9 pushed fully toward thQ back of the ca~satt~ body 100, the wider portion of the longatad, tear-shaped apQrturQ 258 will be align~d with tha apertura 142 in the outlet tube mounting cylind~r 144 (F1gUXe 4) tO allow a ~egment of tubing (not shown) leading ~rom the aperture 142 to be open.
Wh~n the slide latch 240 is pulled out from the front of the ca~sette body 100, the segment o~ tubing (not shown) will be pinched of~ by the narrower portlon o~ the elongated, tear-shaped apertur~ 258.
It is critical that the design and location of thQ
elongated, taar-shaped aperture 258 in the slide latch 240 ensure that the slide latch 240 engage~ th~ main pump unit be~ore the tubing is opened up, and flu~d i~ allowed to flow through the cassette. Likewise, the tubing must be pinched off and the fluid path through the cassette must be blocked be~ore the ~lide latch 240 releases the cassette from the main pump unit. In addition, the choice o~ material for the slide latch 240 is important, with a lubricated material allowing the pinching operation to occur without damaging the tubing (not shown). Example~ of such ,~ . . . _,_ material~ are silicone or Teflon impragnated acetal~ such a~
Delren. -Located at the back of the 81ide latch 240 on the inside o~
tho right slide ~ide 256 at th~ bottom thereo~ i~ a tab 257 (Figure~ 27, 30, and 32) which is used to engaga the main pump unit with the cassette when the ~lide i9 closYd. Locatad on the top sida o~ kha bottom portion 248 to the right o~ the elongated, tear-shaped aperture 258 i5 a ~mall wedge-3haped retaining tab 259 ~Figure 27, 30, and 32). The retaining tab 259 cooperates with the bottom of the slightly rai~ed bordar 146 o~ the cassette body loO ~Figure 2), to resist tho slidQ latch 240 from being frQQly ro~oved once installad into the cassette body 100. When th~ Ylide latch 240 i~ pulled back out from the ~ront of thQ
ca~ette body 100 80 that tha wider portion of the elonyated, t~ar-~haped aperture 258 i5 aligned with th~ aperture 142 i~ the outle~ tube mounting cylinder 144, the retaining tab 259 will angage the ~lightly rai#ed border 146 (Figure~ 2 and 4), re8i3ting the ~lide latch 240 from be:Lng drawn ~ur~her out.
Re~erring now to Figure~ 33 through 36, a one-piece piston cap and boot s~al 260 is illustrated, whlch is the subject o~ the above-identi~ed patent application entitl~d ~'Piston cap and Boo Seal ror a Nedication Infusion System,~ and which is for use on and in the pump cylinder 112 (Figures 3 and 8). The piston cap and boot seal ~60 i~ of one-piece conR~ruction, and i~ ~ade of ~lexibla, resili2nt material, such as silastic ~silicone rubber) or medical grade natural rubber. Natural rubber may be usad to minimize friction, since some sticking of a silicone ruhber pi~ton cap and boot seal 260 in the pump cylinder 112 (Figure B) may occur. Te~lon impregnated silastic or other proprietary ~or~ula0 widely available will overcome thi~ problem. In addition, the piston cap and boot seal 260 may ba lubricatad with silicone oil prior to installation in the pump cylinder 112. The advantage o~ using 3ilastlc is that it may be radiation starilized, wher~a~ natural rubber must be steriliz~d using gas ~uch A~ ethylene- oxide. In addition, silastic has b~tter wear characterlstics than natural rubber, ~aking it th~ pre~erred choic~.
The piston cap and boot ~eal 260 includeæ a piston cap portion indicatad g~nerally at 262, and ~ boot ~sal portion co~pr~sing a retaining skirt 264 and a thin rollin~ 1 2~6.
Tha piston cap portion 262 lnclude~ a hollow cylindriaal ~gment 268 having an enlarged, rounded piston cap h~ad 270 located at the ~op theraof. The piston cap head 270 ha~ a roughly elliptical cross-section, with an outor ~la~ater on th~ ~idas su~ficient to provide a dynamic s~al in the main dia~eter bore 114 o~ tho pump cylinder 112 (Figure 8). The roughly elliptical ~on~iguration of the pi~ton cap head 270 closely ~ito th~ top of th~ main diameter bore 114 oP the pu~p cylind~r 112. Extending from ~h2 top of the pis~on cap head 270 at the center thereo~ is a frustroconical segm~nt 272, with the larger diameter o~ the rrustroconiaal segment 27~ being at the bo~tom thereof attached to ~ pi~ton cap head 270. The rrustrGconical ~egment 272 is of a ~iz~ to elosely fit in the smaller diameter aper~ure 118 o~ the pump cylindar 112 (Figure 8).
The hollow cylindrica~ ~egment 268 and the pi~ton cap head 270 together de~ine a closed end of the piston cap and boot æeal 260 to receive a piston, which will be describad below. The hollow cylindrical segment 268 has located therein a smaller diameter portlon 274, which smaller diameter portion 274 is ~psced away from the bottom o~ the piston cap head 270 to provide retainlng mean~ to retain a piston in tho hollow cylindrical ~eg~nt 268 between the piston cap head 270 and thQ smaller dia~etar portion 274.
The retaining skirt 264 is essentially cylindrical, and is dssigned to f it snugly around the outer diameter o~ the pump cylinder 112 (Figure 8). Prior to installa~ion and with the piston cap and boot ~al 260 in a relaxed con~iguration as shown in Figures 33 through 36, th~ retaining ~kirt 264 1~ located r~ughly around the hollow cylindrlcal ~egment 268. The retaining ~kirt 264 ha~S an inkernal diameter su~iciently ~mall to retain th~ rQtaininq ~kirt 264 in position around th~ pump cylindar 112 (Figure 8) without moving when the pi6ston cap portion 2S2 ~oves.
~ocated around the inner diameter o~ the retaining ~kirt 264 i0 a tortuous p~th 276 leading fr~m one end o~ the retaining ~k~rt 264 to the other. The tortuou~ path 27~ i~ r~quired for ~tQrilization of the assembled ca~Bette, to allow the ~t~r~lizing ga~ to ~terlli e th~ ar~a b~tw~n the in~ide o~ th~ pump cylinder 112 and tha pi~ton cap and boot 8saal 260, which would b6 Glo~ad i and ~ay re~ain un~t~rilizQd if th~ tortuous path ~76 did not s exi~t. In addition, sincQ th~ sterilizing ga~ i~ hot and coolin~
occurs rapidly after thQ 8terilizing operat~on, the tortuou~ path ~76 allow~ pr~s~ur~ equali2ation lto occur rapidly where it oth~rwis~ would not. In ths preferr.ed embodiment, the t~rtuou~
i~ p~th 276 is a serie~ of thread~ in th~ inner diameter o~ the l, r~taining ~kirt 2~4.
Co~pleting the construction of th~ pi~ton cap and boot 52al 260 i~ th~ rolling seal 266, which i~ a segment defined ~y rotating around the centerlin~ of the pi~ton cap and boot ~eal ~ 260 a U h~ving a first leg at the radius of the hollow r~ cylindrical sagment 268 and a econd leg a~ ~he radius of tha reta~ni~g ~kirt 264, with the top o~ the first leg of ths U being at~ached to ~h~ bot~om of the ~ollow cylindrical segment ~68 and th~ top o~ ths ~econd leg o~ the U being attached to the bottom o~ ~he rs~alni~g sk$xt 264. W~en the pi~ton cap and boot seal 260 1B ~n~talled and t~e piæ~on ¢ap port1on 26~ moves in and out 30 in ths ~ain diameter bore 114 in the pump cylinder 112 ~Figure 8), thQ legs o~ the U will vary in length, with one leg becoming shorter a~ the other lag become longer. In ~his manner, the rolling seal ~6 ~rovide~ exactly what its name implie~- a seal between th~ piston cap portion 262 and the retaix~ g 6kirt 264 which rolls as the piston cap portion 2 62 moves .
Re~erring now to Figures 37 through 42, a pi~ton assembly 280 is ~hown which drives the pi~ton cap portion 262 o~ the pi~ton cap and boot seal 260 (Figure 36) in the pump cylinder 112 ~Figure 8). Th~ pistorl assembly 280 has a rectangular base 282 which i~ po~itioned horizontally and located directly bshind the bubbl~ chamber cap 2 3 0 ( Figure 2 4 ) whan tha pi~ton cap portion ~62 i9 fully inserted into the pu~p cylinder 112. The rectangular base 282 has a notch 284 (Figure3 41 and 42) in the ~ront edga therao~, which n~tch i8 ~lightly largor than the tab 232 in the bubble chamber cap 230 (Figure 23 ) .
Extending upward from the front ed~ of th~ r~c~angular base 282 on the 13ft sid~ o~ the notch 284 i~ an arm 286, and extending upward from thQ ~ront edgQ of the rectangular ba~e 282 on the right side of the not~h 284 is an arm 288. At th~ top o~
~he arms 286 ~nd 288 i~ a vertically extending rectangular portion 290 (Figure 38). The rectangular portion 290 as well as tho uppQr portions o~ the arms 286 and 28~ are for insertion in~o and between the pi~ton retaining finger 120 and the piston retaining ~inger 122 in the cas3ette body 100 (~igure 4).
The top o~ tha rectangular portion 2so will contack the bottom of the upper surface 102 of the ca~sette body 100 tFigure 3) to limit the upward movement of tha piston asse~bly 280, the rectangular base 282 being approximately even with the bubble chamber cap 230 (Figure 24) installed in the bottom of the bubble trap 104 o~ the cassetta body 100 when the piston ascembly 280 is in it8 ully upward position. The bottom of the rectangular port1on ~Yu ~ gure 42 ) will contact the tab 232 on the bubble chambsr cap 230 (Figure 24) when th~ piston as~embly 280, the piston head 296, and the pi~ton cap portion 262 (FlgurQ 36) are fully retraoted from the pump cylinder 112 (Figura 8).

~319065 Extending upwards from the top of the rectangular base 282 near th~ back edg~ of tha rectangular ba~a 282 and located centrally with respect to the side edges o~ the rectangular base.
282 i~ a cylindrical piston rod 292. At the top o~ the piston 5rod 292 i9 a reduced diameter cylindrical portion 294, and mounted on top o~ th2 reduced diameter cylindrical portion ~94 is a cylindrical piston head 296. The diameter o~ the piston head 296 i~ larger than the diametar o~ the reducad diametor cylindrical portion 294, and the top of the piston head 296 has rounded edges in the praferred embodiment. Tho piston head 296 1~ designed to be received in tho portion Or the hollow cylindrical segment 268 betwaen the smaller diamater portion 274 and th~ pi~ton cap head 270 in thQ pi~ton cap portion 262 (Figure 36~. Tha reduced diameter cylindrioal portion 294 i~ likewi~e de~g~d to ba received in the amaller diameter portion 274 og the pi~ton cap portion 262.
Th~ top o~ th~ piston h~ad 296 is slightly above tha top o~
the rectangular portion 290, and when the pi~ton assembly 280 i8 in its ~ully upward position, the piston head 296 will have brought the piston cap head 270 and the frustroconical segment 272 thereon ~igure 36) to the top o~ th~ pump cylinder 112 and into the smaller diameter aperture 118 (Figure 8), re~pectively, to completely eliminate volume both w~thin the pump cylinder 112 and wi~hin the smaller diameter aper~ure 118.
25Completing the construction o~ th4 piston assembly 280 are two raised beads 298 and 300, with tha raised bead 298 being on the top surfaca of the rectangular base 282 on the left side o~
tha piston rod 292, and the raised bead 300 beinq on the top surface o~ the rectangular base 282 on the right sida of the 30pi~ton rod 292. Both of the rai ad beads 29~ and 300 extend ~rom the sides o~ the piston rod 292 laterally to the side~ of the rectangular base 282. The raisad beads 298 and 300 will be used to center the piston asse~bly 280 wi~h th~ jaw~ o~ the main pump ~ 3g unit u~ed to drive th~ piston a~sqembly 280, a~ well ag to facilitate r~taining the piston a6sembly 280 in th~ ~aws~
The assembly and configuration of the cassette may now be di~cussed, with re~erenca to an assembled cassette 302 in Figure~
43 through 48, a~ well as to other ~igures speci~ically mentionad in th~ di~cu~ion. The valve diaphragm 170 i~ placed over the top of tha upper surracQ 102 of the cassette body 100, with the aperture~ 172, 174, and 176 placed over th~ hollow cylinders 156, 1~0, and 162, r~spectively. The retainer cap 190 i~ then located 10over the valve diaphragm 170 and the ca~sette body 100, and i~
sacured in plac~ by ultrasonic welding. Nota again that while adhe~ive sQaling may bs u~ad, it i~ more difficult to en~ure the con~istent hermetic seal reguired in the construction o~ ths cassette 302.
15Th~ ~tep o~ firmly mounting the retainer cap 190 onto the ca~ette body 100 ~xerts a bia~ on the Yalve diaphragm 170 (Figuxe 9) causing it to be compres~ed in certain area~, part~cularly over the slightly rais;ed ~order 146 on the top surface o~ the upper surface 102 of the cassette body 100 (Fi~ure 1). Th~s results in excallent sealing charact2ristics, and Qncloses th~ variou~ pas~ageway~ located in the upper sur~ace 102 oP the cas6etta body 100. The ~irst passageway 128 i~ enclosed by the valve diaphragm 170, communicating at one end thereof with the aperture llo and at the other end thereo~ with the area 25between ths cavity 180 and the upper surface 102 o~ the cassatte body 100. The second paAssageway 134 also communicates with the area between the cavity 180 and the upper surface 102 of tha cassette body 100 at one end thereof, with the other end of the second pas~ageway 134 communicating with one end of the 30passageway 132 in the pressura plateau 130.
The pressure diaphragm 182 i~ located above tha surface of the pres~ure plateau 130 (Figures 115 and 116), and a ~pace axist~ betweQn the edges at the side of ~he pres~ure plateau 130 and tho in~Qr diameters o~ the upper cylindrical segment 184 and the lower cylindrical segment 186. This allow~ the pre~sure diaphragm 182 to be quite ~lexible, a design ~eatur~ essential to proper operation o~ the pressure monitoring apparatu~. It may ther~orQ be apprsciated that th2 ~low area between the second pa3sa~way 134 and the third pas~ageway 136 i8 not ~ust the area o~ the passageway 132, but also thQ area between the pre~sure diaphraym 182 and the pre~sur~ plat~au 130, as wall a~ the area around th~ ~ide~ of the pressure plateau 130 ad~acent tha upper cylindrical segment 184 and thQ lower cylindriaal ~egment 1~6.
The third passageway 136 tFigure 1) is also enclo~ed by the valvo diaphragm 170 (Figure 9), and communicate~ at one end with the other ~nd of the passageway 132, and at the other end with the reces~ed lens portion 138. The fourth pa ~agaway 140 i~
enGlo~d by th~ valv4 diaphragm 170, and communicates at one end with th~ r2cessed len3 portion 138 and at ths other end with thQ
aperture 142.
Next, the bubble chamber cap 230 i5 placed on the bottom of th~ bubbl~ chamb~r 106, as shown in Figure 44, and is secured by ultra80nically 3ealing the bubble cha~ber cap 230 to the cassette body 10~. The piston cap portion 262 of the piston cap and boot seal 260 (~igure 36) is inser~ed in~o thè main diam~ter bore 114 o~ thQ pump c~linder 112 (~igure 8), and pushed toward the top o~
tha main dia~eter bore 114~ Simultaneously/ the reta~ning skirt 264 is placed over the outside o~ the pump cylinder 112 and i3 moved up tha outer surface of the pump cylinder 112 to the position shown in Figures 46 and 48, which is nearly to tha top o~ the outer surface of the pump cylinder 112. Next, the piston h2ad ~96 o~ the piston assembly 280 (Figures 37 and 40) is inserted into the hollow cylindrical ~egment 268 o~ the piston cap and boot seal 260, and is ~oraed past the smaller diameter portion 274 until it snaps home, resting against the bottom of the piston cap head 270.

131qO65 Tha ~ 0 latch 240 i~ then in ~rtQd into engagQm~nt with th~ cas~ette b~dy loo, which iY ~coompli~hQd by ~liding thQ le~t e ~ide 254 1nts the latoh supporting ~ln~er 124 on th0 right ~id~ thareo~ and by sl$ding the ri~ht ~ ide 256 into the 5 latch ~upport~ng ~inger 126 on thQ lQft o$de th~reQ~. Tha ~lide latch 240 i~ then pushed Pully ~orward to ~liyn th~ wider po~ion o~ ~he Qlongat~d, t~ar-shaped aperture 258 with the outl~t tub~
mountir~ç1 cylinder 144. An inllst tubQ 304 $~ adh~lv~ly ~ecurQd in th~ r dia~Qt~r o~ the inl~t aperture 238 in th~ bubble 10 ohambe~ cap 230, in ~luid communicatioII with th~ bubbl~ chambar 106. An outl~t tube 306 extend~ through th~ wider portion o~ the ~longated~ t~ar shaped aperture 25~ ~nd 18 adhe~iv~ly seoured ln the ~nner dia~et~r o~ thQ outlet tub~ ~ounting cylind~r 144 in th~ ca~sette body loO, in rluid com~unication with the ~ourth passageway 140 through the apertur~ 142.
Tha ~nlst tub~ 304 and th~ outl~l: tube 30~ are ~hown in th~
rigur~ only in pa ~ ; on th~ir respectiv~ andR not connQcted to the a~e~blad c~sette 302 th~y may h~vs connector ~ittlng~ such ~ etandArd luer connectors (not ~ho~l), which ar~ well know~ in th~ a~t. The us~ o~ adhesi~es to ~ttach th~ inl~t tube 304 and the outl~t ~ube 306 to th~ assambled cassette 302 al~o u~ ze3 te~hnology w~ll known in th~ ar~. For ~xa~pl~, adh~ives such as cyclohexanonQ, methylens di~h~oride, or tetrahydro~uron (THF) may b~ utiliæed.
The Main Pump Unit- The pref~rred embodiment o~ the main pu~p unit used with the present invention includes a number o~
components used to hold, latch, and driv~ the cassette described ~bovs. Referri~g ~ir~t to ~igure~ 49 t~rouqh 53, a latch hea~
310 18 illu6trated which is used to grasp the raised bead 298 and t~e raised ~ead 300 o~ the piston assembly 280 (Figuro 37).
Extending ~ro~ tbe fron~ o~ the la~ch head 3io at the ~op ~hereof on the le~t side is a left jaw 312, and extending ~ro~ the front of the latch head 310 at the top thPreof on the right side iB a I ~ 1 9065 right ~aw 314. Th~ left and rig~t ~aws 312 and 314 hav~ curved indentation3 on th~ botto~ ~id~s th~reo~ to r~c~ive the raised be~d ~98 ~nd the r~ised bead 300 ~Figure 37), r~pactively. A
spaoe betweQn the le~t ~aw 312 And the right ~w 314 ~llow~ them to fit around th~ piston rod 292 o~ th~ pi~ton a88~mbly 280.
A cylindrlc~l aperture 316 i8 located in th~ top o~ the latch h~ad 310, whlch cylindrlcal ~perture 316 i~ design~d to reG~lve a ~ha~t on whlch th~ latch head 310 i~ ~ount~d.
thr~aded ~pertur~ 318 ln the back ~ida o~ th~ 1 tch ha~d 310 ~o~mun1aatQ~ with the ~ylindrical aperturs 316, and will have locking mea~s ~nstall~d ther~in to lock a ~h~t in the cylindrical apertura 316. An apertur~ 320 ext~nds throu~h the lstch hea~ 310 fro~ the l~t ~d~ to ~he right 61de ther~o~ ne~r th~ back and botto~ of the latch head 310.
A notch 322 i8 locat~d in th~ lat~h ha~ 310 at th~ bottom and ~ront th~r2~ ~nd in th~ ~nter th2r~0~, leaving ~ ~ld~
portlon 324 on th~ t eid~ ~nd a side portion 326 on ths rlght eid~. An apertur~ 328 is loc~k~d through th~ side por~ion 324, and ~n apertur~ 330 i8 located ~hrough the sid~ portion 326, which aperturQs 328 ~n~ 330 ar~ a:Ligned. In addition, th~
portion o~ ~he la~ch head 310 including the 12~ ~ aw 312 ha~ a rais~d edg~ 327 ~acing upward a~d backward, and a rai6ed edg~ 329 facing down and ~orward. The portlon o~ th~ latch head 310 including thQ right ~aw 314 ha~ a rai~ed edge 331 facing downward and rorward. The raised edges 327, 3~9, and 331 wlll ba used to li~it thQ move~ent o~ the latch ~aw, wh~ch will b~ discussed bslow.
A ~pr~ng 6aat 332 i shown in Fiqures 54 and 55. which i~
designed to ~it in the notch 322 in the latch head 310 (Figures 51 ~nd 53). The spring seat 332 ha~ an aperture 334 extending therQthrough rxom tha left ~ide to the right slde, which aperture 334 i~ slightly larger than ~he aperture~ 328 and 330 in the latch hea~ 310. The ~prins ~a~t 332 ~180 has a cyllndrical ~egm~nt 336 extending ~ro~ the ~rorat ~lde th~rao~.
A latch ~aw 340 i3 illu~trated in ~lgur~s 56 through 58, whiGh latch ~aw 340 i~ u~e,d to ~r~p ~ bottoD~ o~ the ractangular basa 282 o~ the piston a~e~bly 280 ~iguro 37) and r~aintain the le~t ~nd right ~aws 312 ~nd 314 o~ th~ latch head 310 (F~gur~ 51~ in contact with th~ rai~ed b~ad 298 ~nd the r~ised b~ad 300, re. pectiv~ly. The l~tch ~w 340 has ~ ~ront ~aw por1:ion 342 approximately a~ wldQ a~ the le~t ~nd ~lght ~aws 312 and 314 oX the latch h~ad 310, whlch ~aw portion 342 1~ ths portion of th~ latch ~aw 340 wh~oh oont~cts the bottoDI Or tha re~angular ba~ 282 o~ the pl~ton a~embly 280. Extendlng back ~rom the la~t ~ida of the ~aw portion 30.2 is a l~t arD~ 344, and ex~ending back from the right ~ide o~ thQ ~aw portion 342 i~ a right arm 46.
Th~ l e~t arm 344 ha~ ~n apertur~ 348 (not ~hown~
ther~through ~rom the left ~ide t~ the right side at ~he ~nd o~
the lQ~t arm 344 away ~rom th~ ~aw portion 342. ~ikswisQ, the righ~ arm 346 ha~ an aperture 350 there~hrough gro~ the left ~ide to thc right ~ide at th~ end of tha right arm 346 away f rom the jaw port~on 342. The apertures 348 and 350 ar~ sl~ghtly smaller in dia~eter than the aperture 320 in ~h~ ch head 310 (Figures 49 ~nd 50~.
Extend$ng upward from and at an approximately 8ixty d~gree anglQ with res~ect to the right arm 346 ~ro~ the end o~ the right arm 346 away fro~ th~ jaw portion 3~2 i~ a driving arm 352. At the Qnd o~ the driving arm 352 which i~ not attached to the right ~m 346 i~ a li~ pi~ 354 ~xte~ g to th~ right. Completing th~
construc~ion of the latch ~aw 340 i8 a cylindrical recess 356 located in the back side o~ the jaw portion 342, which cylindrical recess 356 has an inner diameter larger ~han the outer diameter o~ the cylindrical segment 336 of ~he spring seat 332 (Figure 55).

~ -3~-1 3 1 ~065 Referring now to Figur2 59 through 61, the con~truction o~
a ~aw~ assembly 360 from th~ lat~h h~ad 310, the spring ~eat 332, and tha latch ~aw 340 is illustrated~ The spring ~eat 332 ~lts within the notch 322 and b~twe~n the l~t ~aw 312 and the right ~aw 314 Or thh latch h~ad 310. ~ pin 362 i~ inserted through the ap~rture 328 in th~ sid~ portion 324, the apartur~ 334 in th~
spring ~eat 332, and the ap~rture 330 in the 3ide portion 3~.
The pin 362 i8 slzed to fit ~n~yly ln the apertuxes 3~8 ~nd 330, thereby r~taining the pin 362 in place ~nd allowing tha spring seat 332 to rotate about th~ pin 362.
The l~tch ~aw 3~0 i3 mounted onto th~ l~tch head 310 with th~ lQ~t ~aw 312 and th~ right ~aw 314 of th~ latch head 310 ~acing thQ ~aw portion 342 o~ the latch ~aw 340 u~ing a pin 364.
The pin 364 is inserted through the ~perture 348 ~t shown)in the left arm 320, the latch head 310 in the ~p:ring seat 332, and the aperture 350 in th~ right arm 346. The pin 364 i~ sized to fit ~nugly in the apertuxe~ 348 and 350, thsreby ret:aining the pin 364 in place and allowing ~h~ latch ~aw 340 to rotate about the pin 364.
A ~pring 366 ha~ one end t:hereof mount~d over the cyllndrlcal s~gment 336 on the ~pring seat 332, and thQ other end th~r~o~ ~unted ~n th~ cylindrical reces~ 356 in th~ latch ~aw 340. Th~ spring 366 acts to bia~ thQ latch ~aw 340 in either th~
open positlon shown in Figure 59 with thOE ~aw portlon 3~2 o~ 340 away ~rom ~ha le~t jaw 312 and th~ le~t ~aw 312 o~ th2 latch head 310, or i~ th~ closed position ~hown in Figur2 61, w~th the ~aw portion 342 o~ the latch ~aw 340 urged closely ad~acent the le~t ~aw 312 and the right jaw 314 o~ th~ latch head 310. The movement of the latch jaw 340 in bvth direction~ with respect to tha latc~ head 310 i9 limited, to the position ~hown ln Figure 59 by th2 driving ar~ 357 contacting the rai~ed edge 327, and to the position shown in Figure 61 by the right arm 346 contacting the rai~ed edge 32~ and by the ~eft arm 344 contacting the raised edge 331. When ~he assembled cassette 302 is installed, movement --~0--of the lat~h ~aw 340 to the pOE~itiOII of Figure 61 will al50 be lim~ted by the presen~e o~ the piE~ton aasembly 280, with the rectangular ba~e 282 }:~ing gra~ped by tha ~aw~ asse~nbly 360. It will be noted that by movlng the pin 3 54 oithar toward th~ i~ront or toward the back, the latch ~aw 340 may ~ithQr be op~ned or closed, r~;pectivQly.
Re~srring n~xt to Figure~ 62 throu~h 65, ~ main pump unlt cha~si3 370 i8 illu~trated which is d~asignad to mount thre2 indepQndent pump unitY including three drive ~echani~ into which thr~ disposable a~sembled ca~ette!~ 302 may be in~talled.
Th~ a~3embled ca~sette~ 302 ar~ ~ounted on the bottom sid~ o~ the pU~Dp c:ha~sl~ 370 ~hown in Figure 6~, wlth the motors and drlve tra$n b~ing mounted on top o~ th~ pump c:has~i~ 370 (Figur~ 64) and }~lng in~talled in a hou~ng (not ~hown) ~ounted on tsp o~
the pu~p ahaæsi~ 370.
Located on the pump chaæ~i~ 370 ar~ three pairs of ~ngled se~nt~ 372 and 374, 376 and 378, and 380 and 38~. Each pair of angl~d seg~ent~ 372 and 374, 376 and 378, and 380 and 382 derine~
two ~cing channel~ therebetween. In the pre~err2d embodiment, the ~n~l~d s~g~ent~ 372 and 374, 376 and 378, and 380 and 382 ara angl~d ~lig~tly ~urther fro~ tha botto~ of the pu~p chassls 370 n~ar th~ fron~, to thereby havQ a c~mmlng e~ct a~ the a~se~bl2d ca~tta 302 i8 installed and the ~lide latch 240 i~ closed.
Spaci~ical~y~ ~he angled 6agmen~ 372 de~ines a channal facing the angl~d ~eg~ant 3~4, and t~e angl d ~egment 374 define~ a chhnnel ~acing the angl~d &egment 372. The angled ~ag~ent 376 darlne~ a channel facing the angled ~egment 378, and the angled ~egment 378 defines a channal facing the angled Begmant 376. Finally, ~he angl~d ~eg~snt 380 de~ine~ a channel ~acing the angl~d ~egment 382 and th~ ~ngled ~egment 382 de~ines ~ ch~nnel f~cing the angled ~eg~enk 380.
Each of the pairs of angled segment~ 372 and 374, 376 and 378, and 380 ~nd 382 provide~ means on the bottom o~ pump cha~ i5 370 for one assembled cassette 302 to be securely latched to.
The lnverted L-s~aped portion 250 and the inv~rted, backward~ L-shaped portion 252 in the slide latch 240 (Figure~ 29 and 30) o~
the a~samblQd cassette 302 are designed to facilltate attachment to one of the pairs of angled segment~ 372 and 374, 376 and 378, and 380 and 382. With the slide latch 240 pulled back away ~rom tha front o~ the assembled ca~sQtte 302, an area between the front portion 242 of the ~lide latch 240 and the top front o~ the cass~ttQ body 100 and the retainer cap 190 i8 open, allowing the top of the as~embled cassetta 302 to be placed over one of th~
pair3 of angled segments 372 and 374, 375 and 378, and 380 and 382.
By way of example, assume that tha a~sembled ca~sette 302 i~
to be mounted in the first posit~on (the position on the left end 0~ thQ pump chassis 370) on the ~irst pair of angled segmentC 372 and 374. The top surface o~ the asse~bled cassette 302, which is the retainer aap 190 (Figure 43), wi:Ll mount against thQ bottom o~ the pump cha~sis 370 (Figure 62). In order to place the asse~bled cas~ette 302 in condition to be installed, the slide latch ~40 i~ pulled back ~ully ~rom t~e ~ront of the assembled ca6sett~ 302, leaving an area between the front portion 242 of the sl~de latch 240 and the fron~ top portion o~ the as4embled cassetta 302 ~made up of the cassette body 100 and the retainer ca~ 190) facing the front portion 2~2 of the slide latch 240.
The top of the assembled cassette 302 is then placed against the bottom of the pump chassi 370 with the fir~t pair of angled ~egments 372 and 374 fitting in the area between the front portion 242 of the slide latch 240 and the ~ront top portion of the aasembled cassette 302. The slide latch 240 i8 then pushed ~orward into the cassette body 100, sliding the inverted L-6haped portion 250 of the slide latch 240 into engagement with the angled segment 372, and sliding the inverted, backwards L-shaped portion 252 Q~ the ~lide latch 240 into engagement with the I ~ 1 qO65 angled seg~ent 374. The assembled ca~sette 302 will thus b~ held in po~ition on tke bottom o~ the pump cha~si~ 370 until the 31ide latch 240 is ag~in pulled back, relea5ing the assembled cassette 302.
Pro~ect1ng ~rom tha bottom of th~ pu~p cha~si~ 370 are a numb~r o~ ~gments used to position and align tha a~sembled ca~settes 302 in the first (the position on the le~t end of the pump chassi~ 370), second (intermediate), and third (th~ po~ition on the right end of the pump chas~is 370) positions on the pump cha~3is 370. $hree left lat~ral support wall~ 3~4, 3~6, and 388 protrude ~rom the bottom of th~ pump chassi~ 370 at location~ to support th~ upper left side portion o~ the a~sembled cassette3 302 n~ar the back ~hereo~ in proper po~itions $n the ~ir~t, ~econd, and third positions, r~spectively. LiXewise, three right lateral support wall3 39~, 392, and 394 protrude from the bot~om o~ the pump chassis 370 at locations to support the rear-most extending upper portion o~ th~ assembled cassettes 302 on the right sidQ thereo~ in proper positions in the ~irst, second, and third po~itions, respectively.
Additional support and positioning ~or the installation of th~ a~sembled cassettes 302 into the first, second, and third positions are provided for the upper right back corner of the a~embled cassette~ 302 by thres right corner support walls 396, 398, and 400, respectively. The three right corner support wall~
396, 398, and 400 are L-shaped when viewed ~rom the bottom (Figur~ 62), and support and position the back of the assemblsd cassette~ 302 behind the pump cylinders 112 (Figur~ 4) and a portion o~ the right side o~ the assembled cassettes 302 ad~acent the pump cylinders 112. Note that the three right lateral support wall~ 390, 392, and 394 an~ the three right corner support walls 39~, 398, and 400 toge~her provide con~inuous ~upport and positioning for the as~embled cassettes 302 in the first, second, and third positions, respectively.

1~19065 Located in the raised material ~orming the le~t lateral support wall 384 near the back thereof is a thr~aded aperture 402. A single segment of raised material ~orm~ the right lateral ~upport wall 3gO, the right corner support wall 396, and the left lateral ~upport wall 386; located in ~ha~ ~eg~ent o~ ralsed material near the back thereo~ is a threaded aperture 404 on the le~t ~ide nsar the right lateral support wall 390, and a threaded apertur~ 406 on the righk side near the laft lateral support wall 386. Likewi~e, a single ~egment of raised material ~0rm8 thQ
right lateral support wall 392, the right corner support wall 398, and th~ left lateral support wall 388: located in that seg~ent o~ rai~ed material near th~ back ther~of i8 a threaded aperture 408 on the le~t side near the right lateral support wall 392, and a threaded aperture 410 on the right sid~ near the left latQral support wall 388. Finally, a ~ingle segment o~ rai~d material form~ the right lateral support wall 394 and th~ right corner support wall 400 near the back thereo~ i8 a threaded aparture 412 near tha right lateral support wall 394.
Locat~d in the sQgment of raised material forming the right lateral ~upport wall 390, the right corner support wall 396, and thQ left lateral support wall 386 near th~ corner where the right lateral suppor~ wall 390 and the right corner support wall 396 m~et ig an aperture 414 which extends through the ~ pump chassis 370 ~rom ~op to bottom. Locate~ in the segment o~ rai~ed material forming the right lateral support wall 392, the right corner support wall 398, and the le~t lateral support wall 3~8 near the corner where the right 1 ateral support wall 392 and the right corner support wall 398 meet i~ an aperture 416 which extend~ through the pump chassis 370 from top to bottom. Located in thQ segment of rais~.d material forming the right lateral support wall 394 and the right corner support wall 400 near th~
corner where the right lateral support wall 394 and the right ~ 3 1 9065 corner support wall 400 meet i~ an aperture 418 which extends through the pump-chassis 370 fro~ top to bottom.
Not~ that with the assembled cassettes 302 posltioned and mount~d in the ~irst, sQaond, and third posit~on~, the ~perture 414, the aperture 416, and the apertur~ 418, r~spectively, will be directly back of ths pi~ton rods 292 o~ the a~embled ca~ettes 302 (F~gure 46). The aperture~ 414, ~16, and ~18 will be u~ed to mount the drive shafts connected to the ~aw~ assembles 360 (Figura~ 59 through 61) used to driv~ th~ pl~ton aRs~mbly 28~.
- Located betwe~n the la~t lateral 8upport wall 384 ~nd th~
right lat~ral ~upport wall 390 i3 a longitudin~l r~ctangular rece~s 420 in khe bottom ~ur~ac2 o~ the pump ch~ssis 370.
Similarly, located between th~ le~t later~l support wall 386 and the right lateral 8upport wall 392 i~ a longi~udinal rQctangular - r~c~s~ 422 in the bcttom sur~ace of the pump chas~i~ 3~0.
Finally, locat~d betwe~n th~ left lateral support wall 384 and the right lat~ral -~upport wall 390 1~ a longitudinal rectangular roce~s 424 in the bottom ~ur~ace of the pump chas~is 370~ Whil~ the rectangular reces~es 420, 422, an~ 424 do not extend through th~ pump chassi~ 370, oval apertu~ 426, 428, and 430 ~maller than the rectangular r~ces e 420, 422, and 424 are locat~d in the rectangular recesses 420, 422, and 424, respectively, and extend through to ths top ~id~ o* ~he pump chas~is 370.
~ he r~ctangular recesses 420, 422, and ~24 will bQ used to mount sensor modules therein, and tha oval aperture 426, 428, and 430 are to allow the w; reR fr~m ~ ncnr ~o~l~le~ to extan~
through the pu~p chassis 370. Note that with the assembled 30 cassettes 302 positioned and mounted in the first, second, and third positlo~s, the rear-most extending upper portion3 of the assembled cas~attes 302 will be located over the rectangular rece~se. 420, 422, and 424.

Located ln front of the right corner support wall 396 is a circular recess -432 in the bottom ~ur~ace o~ th~ pump chassis 370. Similarly, located in front o~ the right corner ~upport wall 398 is a circular recess 434 in the bottom surface o~ the pump chassis 370. Finally, located in front of the right corner support wall 400 i~ a circular rece~ 436 in th~ bottom surface of th~ pump chassis 370. While the aircular recessa~ 432~ 43~, and 436 do not extend through thc pu~p chassi~ 370, square aperture~ 438, 440, and 442 smaller than the circular recessQs 432, 434, and 436 ar~ located in the circular recesse~ 432, 434, and 43fi, respectively, and extend through to th~ top ~lde of th~
pump chassi~ 370.
~ he circular recesses 432, 434, and 436 will be usQd to ~ount valve actuator ~uides therein, and the cylindrical aperture 450, 452, and 454 are to allow valva actuators to extend through the pump cha~si~ 370 and to orlent the v~lv~ actuator guide~.
Not~ that with the as~embled cas~ette~ 30~ positioned and mountad in thQ f~r~t, s~cond, and third position~, the rircular recess 432, ~h~ circular recess 434, and the c~rcular recess 436, r~8pectively, will correspond exactly with the locations o~ tha do~ed portion~ 178 o~ thc valve diaphragm~ 170 in the a~embled cassettes 302 (Figure 43).
Located to the let o~ the circular recess 432 and in ~ront of the rectangular recess 420 is a circular recess 444 in the bottom ~ur~ace o~ the pump chas~is 370. Similarly, located to th~ left of the circular reces~ 434 and in ~ront of the rectangular reces~ 422 is a circular recess 4~6 in th~ bottom sur~ac~ o~ the pump chassis 370. Finall~, located to the left of th~ circular reces6 436 and in front of the rectangular rece~s 424 is a circular recess 448 in the bottom sur~ace of the pump chassis 370. While the circular recesses 444, 446, and 448 do not extend through the pump chassis 370, cylindrical apertures 450, 452, and 454 of a smaller diamzter than tha circular ~ -46-131~065 r~cessas 444, 446, and 448 are located in the airaular recesses 444, 446, and 4i8, respectively, and extend through to the top side of the pump chassis 370.
The circular racess2s 444, 446, and 448 will bo used to mount pr~a~ure transducer~ therein, and the cylindrical aperture~
438, 440, and 442 are to allow wires ~ro~ ths pr~ssure transducers to ~xtend through th~ pump cha~ 370. Note that with the assembled cassQttQs 302 positioned and mounted in the f~rst, econd, and third positionC, the circular rec~s~ 444, the oircul~r recess 446, and the circular reces~ 448, respectively, will corre~pond with the location of the pres~ur~ diaphrag~ 182 of the valve diaphra~ms 170 in tha assembl2d cassette~ 302 (Figur~ 43).
Projecting from the sur~ace on the top sid~ og th~ pump cha~ 370 are a number o~ raised segm~nts in which threaded apDrture~ are located to support the drive assembly. A
cyl~ndrical rais~d segment 456 i~ located to the left o~ the cylindrical aperture 450 on the top side of tha pump chassis 370.
A laterally extending oval raised se~n~nt 458 is located between the squar~ aperture 4~8 and the cylindrical aperture 452 on the top s~d~ o~ the pump chassis 370. A second laterally extending oval raised segment 460 is lscated between the s~uarQ ap~rture 440 and t~e cylindrical aperture 454 on tha top side o~ the pump aha~sis 370. A cylindrical raised segment 462 is located to the right o~ the ~guare aperture 442 and i8 laterally aligned with the rear-most portlons of the oval raised segment~ 458 and 460.
Finally, a cylindrical raised segment 464 is located to the right of the square aperture 442 and is late~allv a.lian~d with the rront-most portions of the oval raised segment~ 458 and 460.
Located in the cylindrical ratsed segment 456 is a threaded aperture 466. Located in the oval raised segment 458 is a threaded aperture 468 near the rear-most portion of the oval raised segment 458, a ~hreaded aperture 470 near the front-most portion of the oval raised segment 458, and a threaded aperture 472 contrally lacated in khe oval raised segment 458. Similarly, located in the oval raised segment 460 is a threaded aperture 474 near the rear-most portion o~ the oval rai~ed seqment 460, a throad~d aperture 476 near the front-mo~t portion of the oval rai~ed sQgmenk 460, and a threaded aperture 47~ centrally located in thQ oval raised segment 460. Locate~ in the cylindrical raised s~gment ~62 is a threaded aperture 480. Finally, located in the cylindrical raised segm~nt 464 is a threaded aperture 482.
ThQ.apertures 414, 416, and 418 through the pump cha~sis 370 terminate in raised segment~ extanding from the top surface o~
the pump chas~is 370. A rai~ed ~egment 484 iR located around the op~ning of the aperture 414 on top o~ the p~mp cha~is 370, a ralsed ~egment 486 i~ located around the opening of the aperture 416 on top of the pump chas~i~ 370, and a raised segment 488 is locat~d around the opening o~ the ape:rture 418 on top o~ the pump cha~sis 370.
Extending upwardly from the rai~ad ~egment 484 behind the aperture 414 on the left ~ide i8 a guida finger 490, and on the right 8id~ i8 a guide fing~r 49~. Th~ guide finger~ 490 and 492 ar~ parallel and have a space therebetween. Extending upwardly ~rom the r~ised s~gment 486 behind the aperture 416 on tho le~t oide iB a guide finger 494, and on the r~ght side is a guide ~inger 496. Tha guide fingPrs 494 and 496 are parallel and have a 8pa~e therebetween. Extending upwardly from the raised segment 488 behind the aperture 418 on the left side i3 a guide finger 498, and on the right side is a ~uide finger 500. The guide finger~ 498 and ~00 are parallel and have a space therebetweenO
Referring now to Figures 66 through 69, a cassette guide 510 ~or u~e in gulding tho installation of the assembled cassQtte 302 into ths proper location for latching on the pump chassis 370 is illustrated. Disposed to th~ rear of the cassette guide 510 at the right side ig an aperture 512, and at the left side is an 131~065 apartur2 514. The aperture 512 will be aligned with the threaded apertur~ 404 (~igure 62), the threaded aperture 408, or the ~hreaded aperture 412 while th2 aperture 514 will be aligned with the threaded aperture 402, tha threadQd aperture 406, or the threaded aparture 410 to install the cas6ettQ guide 510 in Qither the first, second, or third po~ition.
The top side (Figura 66) o~ the ca~8~tt2 guide 510 ha3 a rectangular reces~ 516 therein, which reatangular reces~ 516 correspond~ in size to the rectanyular recQ~se~ 420, 422, and 424 in the pump chassis 370. The sensor modules will be accommodated bstwean the rectangular rece~ses 516 in tha ca~ette guide~ 510 and th~ rectangular recesse~ 420, 422, and 424 in the pump cha~sis 370. Th~ right sidQ o~ this rectangular reces~ 516 i~
Qxpo~d through a rectangular aperture 518 on the botto~ o~ the cassette guide 510 (Figure 67).
An area 520 on the bottom of the cassatte guide 510 immediately to the ~ront of the rectangular aperture 518 and an area 522 to tha right ~nd to the back of the rectangular aperture 518 i~ rQce ~ed upward from the botto~ surface 524 of the cas3atte guido 510. At the front right corner o~ the rectangular aperture 518 a squar~ segment 528 extends downward to the la~el o~ the bottom sur~ace 524 of the cassette guide 510. Located immadiately forward o~ the sguar~ 6egment 528 is a thin rectangular track 530 extending from the right sido of the Ca88ette guide 510. The thin rectangular track 530 terminates at the front end thereof in a blocking segment 532.
The front end of the cassette guide 510 has a rounded notch 534 therein, which rounded notch is positioned when the cassette guide 510 is installed on the pump chassis 370 to receive the outl~t tube mounting cylinder 144 on the cassette body 100 (Figure 4)~ When the cassette guide 510 is installed on the pump chassis 370, the rear-most portion of the assembled cassette 302 will fit between the cassette guide 510 and the bottom of the 131qO65 pump chas~i~ 370. Accordingly, the cas~ette guide 510 together with tho varlous ~upport wall~ on the bottom o~ the pump chassl~
370 aid3 in the installation of the assembled ca89ette9 302 in the prop~r position for la~ching.
Re~erring next to Figure 70, a pump shaft 540 is illustrated whiGh is ~ssentially cylindrical. Near thQ top and o~ the pump sha~t 540 on ~he front side thereof a cam ~ollower wheel 542 i~
mounted ~or rotation about a short axle 544 ext~nding orthogonally ~rom the pump shaft 540. On the front side o~ the pump sha~t 540 at the ~ame location an alignment wheel 546 is mounted ~or rotation about a ~hort axle 548 extending orthogonally from the pump shaft 540 on the opposite side of the short axlQ 544. Near the bottom end o~ the pu~p shaft 540 on the rear side thereof is a conical reces~; 550, which will be used to attach th~ ~aw8 assembly 360 (Figure 59 through 61) to the pump ~haft 540.
Referring next to Figure~ 71 through 76, a Rlid~ lock 560 which i~ for mounting on the thin r~ctangular track 530 of the cas~atto guide 510 (Figure 67) is illu~trated. Th~ slids lock 2U 560 has a U-~haped slide channel 562 at the front thereof, with th~ open portion o~ the U ~acing le~t and extending ~rom front to rear. Tha right ~ide of the ~lide channel 562, whlch i~ the bottom of the U, has a rectangular notch 564 located near the ~ront thereof, which notch 564 runs ~rom the top to the bottom of the ~lide channel 562.
2xtending back from the rear of the slide channel 562 at the bottom thereof i~ a thin rectangular connecting ~egment 566, whi~h e~fectively extends from the leg of th~ U at the bottom of the slide channels 562. Attached at the rear edge of the rectangular connecting se~ment 566 i~ a U-shaped channel 568 with the open portion of the U ~acing righ~ and extending from top to bottom. The forward leg of the U of the U-shaped channel 568 is attached to the r~ctangular connecting segment 566 at ~he top of the U-shaped channel 568. It will be appreciated that the top surface o~ the rectangular connecting se~m~nt 566 and the top of the U-shap~d channel 568 (which i9 U-~haped) are coplanar, and that the interior sur~ace of the lowermo~t lag of the slide channel 562 i8 also coplanar.
The upper left edge of the U-~haped channel 568 ha~ a bev~l 570 located therson, with the bevel 570 being best ~llustrated in Figure 76. The function of th~ bev~l 570 i~ ~8 a light re~lector, and will becom~ apparent later in con~unction with tha discus~ion o~ the mechanism for latching the a~sembled cassetto 302.
RePerring now to Figures 77 throwgh 79, an essentially cylindrical power module cam 580 i,s illustratedO The power modulo cam 580 has an aperture 582 therethrough for mounting the power module cam 580 on a shaft (not shown), which the aperture S~2 i9 shown from the botkom in Figure 79. The power module ca~
580 ha~ aperture~ 584 and 586 through which means for retaining the power module cam 580 in po~ition on a sha~t may be installed.
Located near to the bottom of the power module cam 580 i~ a groove 588 located around the outer circumference of the power module cam 580. The groove 588 will receive a drive belt which will drive tha power module cam 580 i~ a rotary fashion.
Located above and spaced slightly away from ~he groove 588 in the power module cam 580 is a rstaining groove indicated generally at 590 formed in the surface Or and ext~nding around the circum~erence of the power moduls cam 58 0 . The retaining groove 590 is of essentially uniform width and depth in the surface of the power module cam 580, and variee in distance from the top 6ide of the power module cam 580. As best seen in Figure 77, the portion o~ the retaining groove 590 closest to the top of the power module cam 580 is disposed approximately one-hundred-eighty degrees away from the portion of the retaining groove 590 furthest from the top of the power module cam 580. It wlll be noted that a non~rotating member having a portion th~reo~ engaged in the retaining-groove 590 o~ the power module cam 580 will be driven in a reciprocating fashion as the power modul~ cam 580 i6 tur~ed .
Loca~ed on the bottom o~ the powsr modul~ cam 580 about the out~r dia~et~r thereof is a ca~ sur~ace indicat2d generally at 592. Th~ cam surface 5g2 extend~ lowsr in one portion 5g3 th~
ln the othQr portion 595, a be~t ~hown agaln in Figur2 77. It will be apparent to tho~e skill~ in the art th~t one or more non-rotating member bearing on the cam surface 592 will b~ driven i~ re~iprocating fashion as the power module cam 580 i8 turned.
The con~igurations of the retaining groov~ 590 and the cam ~ur~ace 592 are graphically illustrated in Figur~ 80, which ind~cate~ how three members driven by the power module cam 580 are cau~ed to operate a8 the power modulQ cam 580 i8 rotated through a three-hundred-sixty degree cyd Q. The retaining groove 590 i~ used to drive a pump ~ember, which draws fluid in from a source to ~111 the pump chamber on an intake qtroka, and pump~
thQ ~luid out on a pumping stroke. The cam surface ~92 is used to driv~ two valve members, namely an inlet valve and an outlet valv~, which are driven by portion~ of the cam sur~aca 592 which arQ separated by approximat~ly on~-hundred e~ghty degre~s. It will at once be appreciated that the pump and valve~ baing driven will be those o~ the assembled cassett~ 302.
~he plot of pump displacement in Figur~ 80 illustrate~ that thera i9 a fill cycle during which displacement increases from zero (or near zero) to full, and a pump cycls dùring which displacement decreases from full to empty (or near empty). The r~tainlng groove 590 has two flat portions which correqpond to 39 the ~lat portions of tha pump displacement plot. One of the flat portions 594 is the portion of th2 retaining groov~ 590 which is closest to the top thereof, and this flat portion 594 corre~ponds to the zero displacement portion o~ the pump displacement plot.

t 3 ~ 9065 The other ~lat portion 596 i5 ths portion of the retaining groove 590 which is closest to tha bottom thereof, and thi~ ~lat portlon 596 correspond~ to tha full displacement portion of the pump d~splacement plot.
The portion~ of the retaining groove 590 which are lQcated $ntermediat~ the Plat portion~ 594 and 596 are a po~itive portion 598 which coxrespond~ to the incraasing displace~ent portion o~
the pu~p di~placement plot, and a nag~tlve portion 600 which oorre~pond~ to tha decre~sing displacement portion og the pump di~placement plot. It should ba note~ that th~ ~lat portions 594 - and 596 are ~ubstantial enough to allow valve movQment entirely during the flat portions o~ the pump displacemant plot. In the pr~erred e~bodiment, the ~lat portions 594 and 596 each represent approximately ~ixty degree3 o~ rotatio~al movement, whil~ the positive and negative portions 598 and 600 each represent approximately ona-hundred-twenty degrees o~ rotational movement.
The cam ~ur~acQ 592 o~ the power module cam 580 is described with refsrenc~ to th~ inlet and outlet valve plots of Figure 80.
It will ~ir~t be noted that th~ plots ~or the inl~t and outlet valves are identical, but are located one-hundred-eighty degrees apart. A~ will become eviden~ later in conjunc~ion with the di~cussion o~ th~ valve actuators and the valve actuator guide, the inlet and outlet valve~ are both driven by th~ cam surface 592, but by points on the cam surface which are located one-hundred-eighty degrees apart.
The lower portion 593 of the cam surface 592 correspond~ to the closed positions of both the inlet and outlet valve~, while the higher portion 595 of the cam sur~ace 592 corresponds to the opened positions o~ both the inlet and outle valves. All ~alve movement i9 accomplished entirely during the period~ in which pump displacemen~ remain~ constant. In the pre~erred embodimen~
where pump displacement is constant during ~wo sixty degree I ~ 1 906~

periods and either inGreasing or decrea~ing during two one~
hundred~twenty degree periods, all valve movement i~ accomplished during the two ~ixty degree periods.
In addition, at least one valve is closed at any given time to prevent ~ree flow through the a~sembled cass~tt~ 302.
Th~reror~, it will be appreciatad by those skilled in th~ art that the pQriod during which th~ inlet and outlet valves transition bstween ~ully open and closed po~tion~ will be limited to thirty degree~ or les~ in the preferred embodiment.
During ~ach o~ the sixty degree periods during which pump displacemQnt i~ constant, the on~ o~ the valve~ which i~ open will clos~, and only then will the othQr valve, which wa~ closed, b~ allow~d to op~n.
~oving next to Figure 81, a drlve module assembly 602 is illustrated which includeA th~ power module cam 580 discu~ed above. Tho various parts described in con~unction with Figure 81 are mounted onto a drive module chass3is 60~, which will in turn bo mounted onto one o~ the three pump position~ on the top ~ide o~ the pump cha~si~ 370. As shown in Figure 82, the drive module cha~sis 6Q4 has an apertura 605 ther~through on the la~t side ~h2r~0~, and two apertures 607 and ~09 therethrough on tha right ~ide thereof. The apertures 605, 607, and 609 are ~or use in fastening the drive module assembly 602 to the pump chassis 370.
An ironl~ss core DC motor 606 i5 used to drive the system.
The motor 606 typically has a built-in gear reduction unit to reduce the output speed of the motor 606. The end o~ the motor 606 having the output shaft (not shown) i8 mounted onto the top o~ the drive module chassis 604 at one ide the.~eo~ wi.th the output shaft extending through the drive module chassi~ 604. A
driv~ pulley 608 is mounted on the output sha~t and i~ driven by the motor 606.
A one-way clutch 610 is mounted onto the top o~ the drive modul~ chassis 604 at the other side thereof. Such device~ are 1 3 1 9~65 commeraially available, and arQ also re~err~d to as DC roller clutche~ or Overrunning clutche~. The ona-way clutch 610 suppor~s a drive shaft 612 for rotat~on therain; beth end~ of the drive shaft 612 extend from the one-way clutch 610. ~h~ one-way clutch 610 allow~ the drive sha~t 612 to rotata in one direction only, in thQ prsferred embodim~nt, the rotation i~ clockwi~ when viewQd ~rom th~ top. Tha power module ca~ 5~0 i8 mountad on the bottom end o~ the drive shaft 612 ext~ding ~ro~ th~ one-way alutch 610. A drive belt 613 i~ mountad o~er the drive pulley 608 and in the groove 588 in tha power module cam 5~0. Tho motor 606 will thereby drive the power module cam 580 and thQ drive shaft 612.
FixQdly mounted abovQ th~ one-way clutch 610 i8 an angular incremental position sen80r 614. A ~en~or disk 616 i~ fixedly mount8d on the top ~nd o~ the driva shaft 612, and rotate~ with the drive ~haft 612 and tha power module cam 580. The position ~nsor 614 i~ used to provide angular incremental and absolute position fQedb~ck for control of the drive mechanism and cas~atte. In the pre~erred embodiment, the position sensor 614 should al80 be capable o~ direction ~ensing.
Rs~erring next to Figure~ 85 through 87, a valve actuator 620 i~ illu~trated which is driven by the power module cam 580 (~igure~ 77 through 79). ~he valve actuator 620 includes a thin, es~entlally rectangular portion 622, and has a circular bearing G24 rotatably mounted near the top thereof. The circular outer diamet~r of the bearing ~24 extends ~lightly above the top of the rectangular portion 622. The bearing ~24 is the portion of the valve actuator 620 which will be in contact with the cam surface 592 of the power module cam 580.
The rectangular portion 622 of tha valve actuator 62Q has chamfered edges on tha lower end thereo~ a~ indicated genQrally at 625, and has a ~mall no~ch 626, 628 in both lateral ~ides o~
the rectangular portion 622 at a location above the lower end thex~o~. ~he ~mall notches 626 and 628 ~re for r~ceivirlg means ~or retaining tha valve ~ctuator 620 in po~itlon onc~ it is installQd; thi~ will become ~vident below in con~unction with the dl~oussion O:e th~ as6emb1y o~ the main pump uni'c, Mwing next: to FigurQ~ 83 ~nd 84, a valve actuator guide 630 1B illu~tratQd which is used to ç~uide as~d re~ain in po~itlon pAir~ o~ valvs actuators 620. Tll~ upp~r portion 632 o~ thoe valve actuator gu~da 630 i~ r~ in cro~s-6~ctlon, and lower portiotl 634 1~ circular in cros~-se~tion. Extea~ding v~rtically through both the ~tauare upp~r port~on 632 and the circul~r low~r portion 634 o~ th~ valv~ actuator guido 630 are two apertur~s 63C
and 63R, which ~r~ rQct~ns~ r ~n cros~ ction. Th~ apQrl:ur~
636 and 638 ~r~ aiz~d to allow th~ r~ctangular port~on 622 oX th~
v~lve actuator 620 to ~lide îrealy thareln ln qach o~ th~
apertur~e 63C and 638.
One ~ the valvQ actuator guides ~30 will ba install~d into each o~ the pu~p ~s~ition~ in the pu~p chas~s 370. In the ~ir~t pump po~ition, thQ ~guar~ upper portion 632 o~ the valvQ ac~u2~0r guide 630 wlll be l~cated in the ~uar~ aperturQ 438 on the pu~p ~0 cha~sl~ 370 and ~he circular lower portion 534 Or the valvB
actuator gu~d~ 630 will b~ loca~ed ln ~ o~rcular r~cess 43~ on thQ pu~p cha~a$s 370. In tha ~acond pu~p po~ition~ th~ ~quar~
upper portion 632 wlll be locatQd in thQ squara apertur~ 440 and the circular lower por~lon 634 will be located in the circular 2~ rece~s 434. In the third pump posltion, the sguare upper poætion 632 will be loca~ed in the ~quare aperture 442 and the circular lower portion 634 will be located in the circular recess 436.
Re~rri~g ~a~t to Figures 88 through 90, ~ pres~ur~
transducer 660 is illustrated. One o~ the pressur~ transducers 660 will ba installed in the pump chassis 370 in each pu~p position, in the circular recesses 44~, 446, and 448~ The pressure tran~ducer 660 is essentially cylindrical, wi~h a groove 662 located around the circum~erenca o~ tha pressura transdu~er ~ 56 ~319065 660. Th~ groove 662 19 to receive an elastomerlc o-rlng, which wlll both retain the pressure transducer~ 660 in the circular recesses 44~, 446, and 44a, and provide a ~luid seal. Located on top o~ the pressure transducer 660 is a squarQ sagmant 664 in whic:h i~ located the actual transducer, which s~ar~ ~ogment 664 will bo received in the cylindrical apertur~3 450, 452, and 454.
Extending upward from the square segment 664 are several leads 666 .
ReIerring next to Figures 91 through 96, an optical sensor module 670 is illustrated. Th~ optical sensor modula S70 i8 e85entially rectant~lar in cro~3-se~tion, with a wider rectangular ~lange 672 on top of the rt ctangular portion, and an oval portion 674 above the rtaatangular flange 672. A ~Elex cable 676 extends ~rom the top o~ the oval pox~ion 674. Loc:ated around th~ circu~erenca o~ the oval portion 674 i~3 a groove 678, which will receive an elastomer$c o-ring, which will retain the oval portion 674 of the optical ssn30r modules 670 in the oval apertures 426, 4~8, or 430. The rectangular flange 672 of the optical s~naor msdule~ 670 will fit into th~ rectangular rect3sses 420, 422, or 424, in thR ~ir3t/ second, or third pump po~itions, r~spectively.
Tha rectangular portion o~ tha optical sensor modul~ 670 has located in the ~ront thereof and immediately under the rectangulax ~lange 672 a notch indicated generally by 680, which notch 680 will receive the rearmost portion of the assembled ca~ette 302. The bottom o~ the rectangular portion o~ the opti~al 8ensor module 670 has an optical light source 682 and an optical light sensor 684 located thereon in locations near and eguidi~tant from the right side thereo~. The optical light 3~ ~ource 682 and the optical light sensor 684 are used to detect when the slide lock 560 is in the closed position, a~ will be di cussad below.

Located on the upper surface of the notch 680 in the optical s~nsor module 6~0 axe three optical light ~ource~ 686, 688, and 690, which extend in a line from le~t to right on tha upper ur~ace o~ the notch 680. Located immediately below the three optical light sources 686, 68B, and 690 on the lower surfac~ of the not~h 680 in the optical sensor module 670 near the rlght side thereo~ are thre~ optical light sen~or~ 692, 694, and 696, which al~o ~xtsnd in a line ~rom left to right on th~ lower surfa~e o~ the notch 680. Th~ three optical light source~ 686, 688, and 690 and the thres optical light sensor~ 692, 694, and 696 are used to provide the three cassette identification bits, as will be di~cussed below.
Al~o located on the lower surfac~ o~ the notch 680 in the optical sen~or modula 670 toward the l~t ~ide th~r~o~ iR an op~cal light ~ourcs 698. Th~ optical light ~ourc~ 698 is typically a ligh~ emitting diode~ Located in front of th~
optical light source 698 i~ an optlcal light sen or 700. The optical light sensor 700 i~ typically a phototranæi~tor or like device. Th~ opt~cal light ~ource 698 and ths optical llght ~en80r 700 ar~ u~ed to detect the presence (or absence) of an air bubbl~ in th~ fluid lino ln the cassette. Ths location of the optic~1 light source 698 and the optical light sensor 700 as illu~trated in Figure 9~ is that o~ the prs~erred embodiment, and opera~ion o~ that preferred embodiment as well a~ the con~iguration~ and operational descriptions of several alternate embodi~ent~ are discussed below.
Referring next to Figures 97 and 98, a valve actuator seal 650 i~ shown which is used both to provide a fluid seal and, more importantly, to retain the valve actuator~ 620 (Figures 85 through ~7) in an upward position with theix bearings 624 against the lower portion 593 of the power module cam 580. The outer circumferencQ of the valve actuator ~eals 650 i~ of a size allowing them to b~ retained in a friction fit in the c$rcular reeesses 432f 434, and 436 below the valve actuator guides 630.
A metal r~ng (no~ ~hown) ~ay be molded into the outer diametQr o~
th~ valve actuator seals 650 to better enable them to be better retained in the circular reces~as ~32, 434, and 436.
Two apertures 652 and 654, which ara r~ctangular in con~iguration, are located in th~ valvQ actuator ~eal 650 to rec~ive the bottom portions o~ thQ rectangular portio~ 622 o~ the valva actuator 620. The lengths of the apertures ~52 and 654 are 3horter than the width of the rectangular portion 622 of the valve actuator 620, with the small notches 6?6 and 62~ in the rectangular portion 622 being used to capture to ends of one of the aperture~ 652 and 654. It will bQ appreciated that the small notch~s 626 and 628 of the valve actuators 620 will engage th~
ap~rtures 652 and 654 in the valYe actuator seal 650, thereby allowing the valve actuator ~eal 650 t:o exert a bias on thQ valve actuators 620. A~ will be sQen below, the bia~ exerted by the valve ac~uator seal 650 on the valve actuatoxs 620 is an upward ona, urging ~hQ valvs ac~uators 620 again~t the lower portion 593 of th~ power module ca~ 580.
~o In the previous di~cussion~ of tha various parts of thQ main pump unit, th~ function and in~errelationship between parts has been bri~ly discussed. BeforP moving on to the operation of the main pump unit and the assembled cassettQ 302, a hrief di~cus~ion of th~ ass~mbly of the main pump unit is in order. Thi~
di8cus~ion specifically refer~ to Figures 62 through 65 (the pump chasais 370), Figure 99, and Figure 112, and also to other figures which are specifically mentioned in the discus~ion.
A pump shaft bearing 640 is installed in both the top and the botkom o~ each of the apertures ~14, 416, and 418 in tha pump chassi~ 370. The pump shaft bearing~ 640 tFigure 112) are essentia1ly cylindrical and have a cylindrical aperture therethrough. In the preferred embodiment, the outer sur~ace o~
the pump shaf~ bearings 640 have a raised portion or ridge 641 near t~he top thereof and fit in the ap~rtur~ 414, 416, and 418 ~rom the ~op and- the bottom ther~o~ in an lnter~er~nce ~it to retain them in the apertures 414, 41S, and 418 in the pump cha~si~ 370. The pu~np ~haft ~earing 640 are prererably mad~ Or a 5 low f`riction ~na~eri~l ~uch as Teflon to allow th~ punp ~ha~t~ $40 to ;~ov~ ~re~ly th~rein. ~t will al~o b~ ~pprecl~ta~l that a in~l~ bearing could be used ~n ~ h o~ the apertur~ 414, 416, and 418 ~ n the pu~p chassis 370 which b~ar~ng would ext~nd all th~ way thrcugh the apertures 414, 416, And 418.
N~xt, the valve actuator guide 630 are in~t~lled from the botto~ Or t~c pump cba~is 370 into th~ cir~ular reces~ 432 and tha ~ r~ ap~rture ~38 ~ n th~ fir61t pump po~ition, into the circul~r reoes~ 434 and the ~quare aperture 440 in th~ ~econd pUDlp position, ~nd into the circular rec~s 436 and t~e ~quare aperture 442 ~n th~ third pump position. With the valvo actuator guid~s 630 in~talled $n the pump cha~ 370 the bottom ~ur~a~e of th~ valv~ actuator guide~ 630 leave~ a portion o~ the circul~r rece~e~ 432, 4~4, and 436 open from the bottom ~id~ o~ the pu~p cha~is 370. Th~ valv~ actuakor ~eal~ 650 (Figur~ -97 o.nd 98) 2~ will ~ ln talled later in th~ circular r~cesse~ 432, 434, ~nd 436 ~low th6D valv~ actuator gaides 630~
T~ n~ t~p in the a~se3n~ly i~ to ~nstall th~ t:wo ~en~or ~odul~R. The pre;sura tran~3ducers 660 (Figuree 88 through 90) ar~ lnstalled from the bottom o~ the pu~op chassi~ 370 into the ciraular rece~ses ~44, 446, and 448. ~h~ pressure transducer~ 660 are essQntially cylindrical, and with 0-rings in the groovas 662 fit ~nugly into the circular recesse~ 444, 446, and 448 with th~ir bottom surfaces flush with the bottom 6urfaca o~ th~ pump cha~sl~ 370 around the circular recesse~ 444, 446, ~nd 448; the top~ of the cyl~ndrical portion o:E the pressure trAn~ducer~ 660 ~lt against th~ ~ylindrical aperture6 450, ~52, an~ 454 in ~he pump chas~is 370. Not shown in the drawing~ i~ the preferred e~bodiment'~ us~ of a thin membrane adhe ively placed over the TRAD~MARK
~;: r ~ -6~;

~ 3 1 ~0~5 bottom o~ ~h~ pressure transducer 660 and th~ por~ions of the bottom sur~ace o~ the pump cha~sis 370 thereabout. Thi~ thin membrane protact~ the pra~sure transducer 6~0 ~rom fluids which may inadvertently or accidentally end up on th~ d~vlc~.
The optical sensor a~sembles S70 (Figures 91 through 96) are installed in the rectangular recesses 420, 422, and 416 o~ the pump chas~i~ 370, with the oval portion~ 674 o~ the optical 3ensor modules 670 fitting into the oval aperture~ 426, 428~ and 430. The optical sensor module~ 670 are retainQd in po3ition ~y thQ pre58ur~ o~ 0-rings in ths groove~ 678 in the optical sensor modules ~70, and by the ca~sette guides S10c Th~ n~xt step in th~ a~sembly o~ the main p~mp unit m~chanical component~ onto the pump chassi~ 370 is the installation of the cassette guide 510 (Figures 66 through 69)and th~ slide lock 560 (Figures 71 through 76). The slid0 lock 560 i~ in~tall~d on~o the cassQtte guide 510 by placing the portion o~ the slide lock 560 including the bottom of the slide channel 5~2 into the r~ctangular aperture 51~ in th~ ca~s~tte guide 510 ~rom the top, with the rectangular colmecting ~2~men~ 566 of ~he slid~ lock 560 extending over the portion o~ the area 522 in the back o~ the aa88ette guide 510. Thi~ align3 tho interior of the U-shaped 61idQ channel 562 on the ~lida lock 560 with the back end Or the thin rectangular track 530 on the cassette guide 510.
The slide lock 560 is then moved forward with respect to the Ca65ett~ guide 510, with the interior oX th~ slidQ channel 562 ~itting over the thin rectangular track 530 until the blocking segment o~ the cassette guide 510 is contacted by the slida lock 560.
The caRsette guldes 510 together with the slidQ locks 560 may then be mounted into the three pump position~ on the pump chassi~ 370, which already contain the optical sensor module 670, using two screws (not shown). In the ~irst pump position, a screw is placed through the aperture 514 in th~ cassette guide ~ 6~

131~065 510 into t~e thr~ade~ aperturQ 402 in the pump cha~is 370, and a ~cond screw is placad through the aperture 51~ in the oas~ette gulde 510 into the ~hreaded aperture 404 in the pump chas3is 370.
In the second pump position~ a ~crew i~ placed thr~ugh the aparture 514 in the cassette guide 510 into thQ threaded aperturq 406 in the pump cha~sis 370, and a second ~crew ~8 placed through the aperture 512 in the ca~s~tte ~uide 510 into the thread~d apQrturQ 408 in thQ pump chassis 370. In the third pump position, a screw is placed through thP aperture 514 in the cas8ette guide 510 into the threaded apsrture A10 in the pump ~has~i~ 370, and a ~econd ~crew i~ placed through the aperture 512 in tha ca~ette guide 510 into the threaded apertur~ 412 in the pu~p chas~i~ 370O ~y w~y o~ exampl~, the ca~ettQ guide 510 and the sl$de lock 560 are shown mounted in the fir~t pump position in Figure 99.
Next, the pump sharts 5~0 are installed in the pump shaft bearing~ 640, which hav~ pr~viously been in~talled in the aperture~ 414, 416, and 418. Th~ e.nd of the pump shafts 540 ~ont~ining the conical r~cess 550 therein are in~erted through the pump ~haft bearings 640 from tha top, with the alignment whe~l 546 b~ing locatQd between one o~ th~ three pair~ of guide ~ingers, namely thQ guide finger~ 430 and 492 ~or tha fir~t pump position, th~ guide fingers 494 and 496 for the second pump position, and ~he gui~e ~ingers 494 and 496 for the ~hird pump position. For example, the pump shaft 540 is ~hown in~talled in the first pump position in Figure 112.
The valve actuators 620 are installed next, with one pair of the valve actuators 620 being installed in each pump po8ition .
The bottom end~ of the valve actuators 620 having the chamfered edges 625 are inserted through the top side~ o~ the valve actuator guides 630, with one pair of the valve actuators 620 being installed in each of the three valve actuator guides 630.
The pair of valve actuators 620 are inserted into the apertures 636 ansl 638 $n the valve actuator guide~ 630 with thQ bearings 624 on each o~ ~e pair oî the valve actuator~ 620 facing away ~rom aach other.
It will be appreciatQd that the re ::tangul~r portions 622 o~
5 th~ v~lva actuator~ 62 0 will Qxtend downward through the aperturQs 636 and 638 in the valve actu~tor gu~des 630. ~
~tatQd above, valve actuator s~als 650 ~re used in each oi~ the thr~e pump po~ition~, and are mountQd ~tro~D the bo~tom o~ the p~Lmp chas~i~ 370 into l:he circular races~es 432, 434, and ~36 balow th~ valv~ actuator guide6 630. 5h~ outer c~ rcum~er~ncQ o~ tha valvQ ~ctuator ~eals 650 cause~ them to be retain~d in a ~riction ~it in th~ clrcular recesses 432, 434, and 436.
ThQ low~r end~ of the ractangular portion~ ~22 o~ aach pair O~r the valve actuatora 620 ~xtend downward through the apQrtur~
652 ~nd 654 in th~ valve actuator ~1 650. Th~ ~mall notche~
~26 and ~28 in on~ o~ the valve ~ctuator~ 620 in each pair i~
retain~d in tha aperture 652 in the valve actua'cor ~al 650, and the oth~r on~ o~ thf~ valve actuators ~20 in each palr i5 retained in th~ apertur~ 654. As ~hown in Figure~ 113 and 114, the valve ~ ~o a~tu~tor s~als 650 will t~nd to urg~ the valvs actuator~ 620 in an upward diraction. In thQ preferred embodiment, ths bottoms of tha valv~ actuators 620 having the chamfer~d ~dge~ 625 will protrudc ~omQwhat ~ro~ the bottom ~ur~ac~ o~ th~ pump chassis 370 around ~h~ circular rece~s~s 432, 434, and 436 ~ven w~en the valv~ ~ctuator~ 620 are in their open position. For example, in thair closed position they may protrude approxim~tely th~rty thou~ands o~ an inch, and in their open po~1tion they may pro~rude seventy ~housands o~ an inch.
Thi~ upward biasing o~ tha valv~ actuator 620 i~ es~antial both to allow tha assembled ca88ette~ 302 to bs ~raely in~rted, and to ma$ntain the valve actuators 620 in an upward po~itlon with th~r bearings 624 agains~ the lower portion ~93 of the power module cam ~80. Tha valva actuator 3eal~ 650 accordingly ~ 63-1 3 ~ 9065 function bQ~h to provide a fluid ~eal and to bia~ th~ valve ac~uators 620 in-the upward po~ition d~cribed.
The next ~tap in the acse~bly o~ tha main pump unit i~ to in~tall a drive ~odule assembly 602 (Figure 81) onto each o~ the thres pump positions on the pump chas3i~ 370. In th~ Pir~t pump poait~on, tho drive modula assQmbly 602 will be ~upported above the top o~ the pump cha~sis 370 by the cylindrical raised ~gment 456 and the oval raised segment 458. Thre~ scr~w~ ~not shown) will be used to secure the drive moduls a~se~bly 602 in tha first pump po~ition, with a fir~t screw being plac~d through the ap~rtur~ 605 in ~hs drive module chassi~ 604 into thQ threaded ap~rture 466 in the pump chassi~ 370, a second ~crew being placed through the aperture 607 in tha drive module chassis 604 into the thraaded apertur~ 468 in the pump chas~is 370, and a third screw b~ing placed ~hrough th~ aperture 609 in the drive module cha~
604 into the threaded apartura 470 in the pump chassi~ 370. In the ~irst pump po~ition, the power module cam 580 is supported directly above the square aparture 438 in the pump chassis 370, and thQ valv~ actuator guide 630 and ~hQ two valve actuators 620 located in the first pump position.
In th~ second pump position, tha drive module asse~bly 602 will be ~upported above the top of the pump chassis 370 by the oval raised segment ~58 and the oval raisad segment 460. Three screw~ (not ~hown) will b~ us~d to secure the drive module a~se~bly ~02 in the second pump po~ition, with a ~ir t 6crew b0ing placed through the aperture 605 in the drive module cha~sis 604 into the threaded aperture 472 in the pu~p chassis 370, a s2cond screw being placed through the aperture 607 in tha drive module cha~is 604 into the threaded aperture 474 in the pump chas is 370, and a third ~crew being placed ~hrou~h the aperture 609 in the drive module chassis 604 into the threaded aperture 476 in the pump chassis 370. In the second pump position, the powQr module cam 580 is ~uppor~ed dlrectly abova the ~quare -~4-aparture 4~0 in the pump chas~la 370, and the valve actuator guid~ 630 and tha two valve actuators 620 locatad in the ~econd pump position.
In th~ third pump po~ition, the drive module assembly 602 will be ~upported above the top o~ the pump cha~3i~ 370 by the oval raised segment 460, the cylindrical rais~d ~egment 4~2, and the cylindrical raised segment 464. Thr~e scr~w3 (not ~hown) will be us~d to secure the drive moduls as~embly 602 in th~ thlrd pump po~ition, with a fir~t screw being plac~d ~hrough ths aperture 605 in the drive module chas~is ~04 into the thr~aded aperture 478 in the pump chassis 370, a second scr~w being placed through thQ aperture 607 in th~ drive module cha~si~ 604 into the thread~d aperturo 480 in the pump chassis 370, and a thixd ~crew being pla~ad through the aperture 609 in the drive ~odule chas~is 604 into th~ threaded apertur~ 482 in the pump chassi~ 370. In the third pump position, the power ~odule cam 580 i supported dir~ctly abov~ the square aperture 442 in the pump chassi~ 370, and thQ valve actuator guide 630 and the two valve actuator~ 620 located in ~he third pump posltion.
The ~inal component to be installed i5 the ~awR assembly 360 (Figure~ 59 through 61), with one jaws assembly 360 being installed in each of the three pump positions onto the bottom o~
the pump shafts 540, which are installed in the apertures 414, 416, and 418. The bottom end of the pump shaft 540 having the conical rscess 550 therein i5 inserted into the cylindrical aperture 316 in the latch head 310 of the jaws as~embly 360. A
retaining screw (not shown) is screwed into th~ threaded aperture 318 in the latch head 310, and into the conical rece~s 550 of the pump shaft 540 to retain the ~aws assembly 360 in place on the bottom o~ the pump cha~sis 370.
The location of the in~talled jaws assembly 360 i8 hown in Figure 99, with the slide lock 560 and the latch ~aw 340 in the open position. The link pin 354 on the latch ~aw 340 i9 located in the U-6haped channel 568 of ths slide lock 560, and movement of the slida lock 560 will accordingly cau~e the latch jaw 340 to move. When the slide lock 560 i~ fully ~or~rard, a3 shown in Figure 9~, the~ latch jaw 340 will ~e in the open position, wlth the ~aw portioTI 342 o~ the latch ~aw 340 away ~rom the right jaw 314 of tha latch head 310. When the ~lide lock 560 i~ pu~hed toward the back of the pump cha~3si~ 370, a~ shown in Figura loO, the latch ~aw 340 will be in the clo~ed po~ ion, with th3 ~aw portion 342 of the latch jaw 340 closely ad~ac~nt the right jaw 314 o~ the latch hea~ 310.
Thi~ compl~te~ the di~cussion of the as~embly o~ tha main pump unit with threQ pump po~itions. It will, o~ coursa, be apprsciated that the main purQp unit may bQ con~truct~d with dif~erent numbers o~ pump po~itions without departing from th~
teaching~ herein. It i8 now appropriate to discuss th~
installatlon o~ tha assembled cass~tt~ 302 into the first pump po3it$0n, which i~ ~he subje~t o~ the above-identified appllcatlon entitled "Cassette Loading and Latching Apparatus ~or a Medicatlon Infusion System," and the operation of the device to pump ~luid and to perform the other associated function~. The operat~on~ o~ the ot~er two pump positions are identical to the operation o~ the first pump position described below.
With the slide latch 240 pulled back ~ully away from the front of the assembled cassette 302 (Fiyures 43 through 48), the wider portion o~ the elongated, tear-shaped aperture 258 in the slide latch 240 will close the outlet tube 306, preventing fluid from flowing through the assembled cass~tte 302. The inlet tube 304 is connected to a fluid source such as an IV ba~ (not shown), and the outl~t tube 306 is connected to a fluid delivery device such as an injection set (not shown), tha u~e oP which i~ well known in the art. The slide latch 240 is opened, together with any other closures in the IV bag line, and fluid fills the llnes, the asse~bled cassette 302, and the in~ection set. By tapping or shaking the asse~bled cassette 302 any residual air bubble~ will ~low out through the line. The slide latch 240 is then pulled back and the outlet tube 306 is clo~ed, and tha sy~tem is in a primed condition with the assembled cassette 302 r~ady to be in6talled onto the main pump unit.
When the ~lide latch 240 i~ pulled back, an opening is le~t betw~an tho ~ront portion 242 o~ the ~lld~ latch 240 and the front top portion o~ the a~sembled ca~Qtte 302 (mada up o~ the cas~ettQ body 100 and the retainer cap 190) facing the front portion 242 of the slide latch 240, ~y way o~ the example used horein where the a~sembled cassett~ 302 i~ to be mounted in the first position (the po3ition on the le~t end of thQ pump cha~sis 370), the opening between the ~ront portion 242 of th8 Blide latch 240 and kh~ Pront top portion o~ tha as~embled ca~sette 302 will admit tha first pair o~ angled se~m0nt~ 372 and 374 as tho as~emblQd cassette 30~ i~ in~talled. ThQ top surface o~ the a~sembled cassette 302, which i~ tha retainer cap 190 (Figure 43), will mount against the bottom of the pump chassi~ 370 (Flgur~ 6~).
Prior to installing the a~semblQd cassette 302 into the main p~mp uni~, thQ slide lock 560 must be fully forward with the lat~h ~aw 340 opened away from the latch head 310, as mentioned previou~ly and as shown in Figure 99. In addition, tha jaws a~se~bly 360 should be in it~ fully upward position, which may be achieved by u~ing the motor 606 to ~rive tha power module cam 580 to cause the iaws assembly 360 to be driven to this position using the position sensor 614.
With the rear-most edge of the assembled cassette 302 tiltsd up~a~, th~ ~@~-most edg of ~he top o~ the assembled cassette 302 is then placed against the bottom of the pu~p chassi~ 370 between the pressure transducar 660 (mounted flush with the bottom o~ the pump chassis 370) and the top ~ide of the cassette guide 510. The rear-most por~ion of the top o~ the a~sembled -67~

ca~ett~ 302 is slid toward th~ back of th~ pump chaa~is 370 into posltion between the left lateral support wall 384 on the lef~ sidQ thereof and the right later21 ~upport wall~ 390 on the right side thereo~, with most of thQ r~ar-most portion of the top s o~ th~ as~a~bled ca95ette 302 f itting into thQ notch 680 in the optical sensor module 670. The upper righ~ back corner of the as~mbled ca~s~tte 302 is supported and posit~oned in tha baoX of the a~2~blQd cassette 302 behind the pump cylind~r 112 (Fiqure 4) and on the portion of the right 3ide o~ the as~ambled cas~ette 302 ad~acent the pump cylind~r 112 by th~ right corn~r ~upport wall 396.
Wh~n the a~embled ca88~tt~ 302 is pushsd fully back in pli~ce, th~ front of the assembled cassstte 302 i~ t$1ted upward agiain~t the bottom of the pump chas~ 370, with the first pair Of an~led seg~ent~ 372 and 374 on th~ ~ottom of the pump chas~i~
370 ~it~ing into the axea ~etwe~n the front portion 242 of thQ
~lide lakch 240 and the front top portion of th~ a~se~bled ca~a~tte 302. The ~lide latch 240 may thon be pushed into the ca~tte body 100, ~liding the inverted ~-~haped portion 250 o~ th~ alide latch 24~ into 2ngagement with the angled ~agm~nt ~72, a~d sliding the ~nverted, bacXward~ ~-shaped portion 252 o~ the slide latch 240 into engagement with the angled s~g~nt 374. The assembled cas~tte 302 will thus bQ held in po~tion on the bottom of the pu~p chassis 370 until the slide latch 240 i5 a~ain pulled back, releasing the assembled cassette 302.
Simultaneously, the outlet tube 306 will be opened, but ~luid will not ~low through tha outlet tubQ 306 since at least onQ of the valve actuators 620 will be in its ~ully downward position at any given time, thereby preventing free flow through ths as~embled cassette 302 whenever the assembled cass2tte 302 is installed on the main pump unit. It will also be noted that in this initially in9talled position, the piston cap portion 262 is located at the very top of the pump cylinder 112.
It will be appreciated as discussed above that the power module cam 580 will operate both the reciprocations of the piston assembly 280 and the movement of the valve actuators 620A and 620B (Figure 112). This piston and valve drive system is the sub~Qct of the above-identified application entitled "Mechanical Drlve Sy~tem for a Medication Infusion SystQm." The movement of the piston assembly 280 and the valve actuators 620A and 620B
will correspond to the chart~ of Figure 80, with the initially installed position corresponding roughly to the zero degree po~ition of the charts. In this position, both the inlet valve actuator 620A and the outlet valve actuator 620B arQ in their closed positions.
Note that th~ op~n po~itions of the inlet valve actuator 620A and the outlet valve actuator 620B are their fully upward position~, and that their cloged positions are their fully downward positions. Without the inlet valve actuator 620A and thQ outlet v~lve actuator 620B in place on the domed portion 178 of the valve diaphragm 170 o~ the assembled cassette 302, the area including the first passageway 128, the smaller diameter aperture 118 to the pump cylinder 112, and the second passageway 134 i~ entirely open and fluid flow therein is unrestricted.
When the inlet valve actuator 620A is in its closed or fully downward position, the portion of the domed portion 178 located intermediate the first passageway 128 and the smaller diameter aperture 118 is forced down onto the portion of the slightly raised border 146 between the first passageway 128 and the smaller diameter aperture 118, thereby preventing fluid flow between the first passageway 128 and the smaller diameter aperture 118. This position of the inlet valve actuator 620A is referred to as its closed position.

Similarly, when the outlet valve actuatcr 620B is in its closed or fully downward po~ition, th~ portion o~ tha domed portion 178 located intermediate th~ smaller diam~ter aperture 118 and the second passageway 134 i~ forced down onto the portion of the slightly rai~ed bor~er 146 betwe~n the ~maller diameter aper~ure ll~ and the second passageway 134, hereby praventing ~luid flow between the smaller diametsr aperture 118 a~ the ~scond pas~agsway 134. Thi position of th~ outlet valve actuator 620B is referred to a itR open position.
~he mo~or 606 will begin to dri~ the powsr modulo cam 580, causing ths inlet valva actuator 620A to op~n, with th~ outlet valve actuator 620B remaining clo~ed, ae ~hown in Figuro 113. A3 the power module cam 580 continues to be turned by th~ motor 606, th~ piston cap portion 262 will be drawn downward in th~ pump cylind~r 112, cau~i~g ~luid to be drawn into the pump cylind~r 112 ~rom the fluid source (nat ~hown) through the inl~t tub~ 304, the bubbl2 trap 104, and the fir~t pa!3sag~way 128. Wh~n the pump cylinder ll~ is filled, the inlet valve actuator 620A i8 closed.
Only a~ter the inlet valv~ actuator 620A i~ fully closed will the outl~t valv~ actuator 620B be open~d. ~igure 114 show~ the ~yste~ with the outlet valve actuator 620B opened, prior to any fluld b~ing pu~ed out. The main pump unit responds to an electronic control system (not shown) which operates the sy~em.
Thi0 electronic control system, which i~ preferably microproces~or-ba~ed, may be either conventional as known in the art, or it may differ to enhance the unique mechanical design of the system discussed herein.
Fluid will be pumped ~y the mo or 606 turning the power modula cam 580 to drive the piston cap portion 262 upward in the cylinder, forcing fluid out of the pump cyllnder 112 t and eventually out o~ the assembled cassette 302 through the outlet tUbQ 306, from which lt is supplied to tha patient through the in~ection set (not shown). It will be appreciated by those 1 ~ 1 9065 skilled in th2 art that the 5y8tem may pump ~luid at any rate chosQn, by operatlng the motor 606 to pump ~luid~ In addition, th~ use of the position sensor 614 will provida a ~eedback ~ignal indlcating the exact position of thQ power modul~ cam 580 and the pi8ton a~sembly 280, thereby indicating how much ~luld has been pumped by the device.
A~ noted pr~viou~ly, th~ rear-~ost portlon o~ tha as~embled cas~Qtte 302 is located in th~ not4h 680 o~ the optical 6en80r ~odule 670 when the cassetta i8 installad in the main pump unit.
Thi8 i~ illustrated in Figures lOl and 102, which i~lustrate only th~ as3embl2d cassette 302 and the optlcal ~ensor module 670. In some 8ituation~ it may be de~irabla to use several dl~erent type~ Or assembled ca6se~tas 302 with the system dsscribed herQin~ For .example, dif~erent cassettes may reguire different stroke volume~ to provide di~ferent flow ranges, or requirs di~erent fitting8 on the inlet tube 304 and/or the outlet tube 306 of the cassettes. Spacial application cassettes such as enteral pump cassettQ~, continuous arterio-venous hemofiltration (CAVH) cassettQs, continuous blood sampling cassettes, or autotran~fu~ion cassettes may be manu*acturQd.
The u~e of the wrong cassette may present a hl~h degree o~
danger, so it will be perceived that i~ i~ highly de~irable to idanti~y th~ particular cas ette in~talled. This may be accompli~hed by the use of the three ca~sette identifying indicia 148, 150, and 152. By making each Or these indicia a binary bit, up to eight different codes may be generated. By using redundant coding to ensure fail-safe operation, three different cassettes can be identified. In addition, the ab~ence of a cassetts can also be detected. In the exa~ple illustrated in the drawing~, the first cassette identlfying indicia 148 and the third cassette idantifylng indicia 152 are of a first type (identified as a logical ~ne for convenience), and the second cassette identifying 13~9065 indicia 150 is o~ a second type (identifiQd as a loglcal zero ~or convanienc~).
With the assembled aassette 302 in~talled wlth it3 rear-mo~t portlon located in the notch 680 o~ th~ optical ~ensor module 670, the Pirst ca~sette identifying indicia 148 is aligned with the ~irst pair of sensor element~, namaly tha optical light ~ourc~ 686 and the optical light ~ensor 692. Si~ilarly, th~
sacond ca s~tte identifying indicia 150 is allgnQd with the second pair of sensor elements, namely the optical light sourae 688 and tha optical light sensor 694. Likewi~e, the third c~ssette identi~ying indicia 152 i3 aligned with the third pa~r oP sen~or elements, namely tha optical light sourc~ 690 and the optical light ~ensor 696.
The second oassette identi~ying 1ndicia 150 (tha logical zero) and the second pair of s~nsor e~lament are shown in Figur~
103. Light from the optical light ~ourG~ 688 shines through the aperture 208 in th~ retainer cap 190, and onto the cassette body 100, where it i~ dispersed by the ,second cassette identifying indicia 150, which comprises an inverted V molded into the bottom of tha upper surface 102 o~ the cassette body 100. Note that variou~ prism types of construction could also be used to disperse the light, which does not reach the optical light sensor 694, rs~ulting in a logical zero being output by tha optical light sensor 694. For example, the inverted V could be molded into tha top side of the upper sur~ace 102 o~ the cass2tte body 100. Other alternatives include u~ing paint or other physical blocking expedients instead of a dispersing lens, or selectively ~olding or not molding one or more of the aperture~ 206, 208, and 210 in thQ retainer cap 190 (Figures 13 and 14).
The third cassette identifying indicia 152 (the logical one, like the ~irst cassette identifying indicia 148, which is not shown here) and the third pair of sensor elements are shown in Figure 104. Light from the optical light source 690 shines ~ 3 1 9065 through tha aperture 210 in the retainer cap 190, and onto the third ~assatte identi~ying indicia 152 on the oa~s~tte body 100.
Tha third cas~ette identifying indicia 152 is a cylin~rical pro~ection axtending up ~rom the upper s~rfaca 102 G~ tha ca~sette body 100, which cylindrical pro~ction acts like a light pipe to conduct khe light to the optical light sensor 69~, where it cause~ tha optical light sen~or 69~ to genarate a logical ona output. Note that in the preferred embodiment9 the ca~tt~ body 100 i8 con~tructed o~ clear plastic to allow thQ ~irst ca~setta identi~ying indicia 148 and th~ third ca86~tte identi~ying indicia 152 to conduct light therethrough. Also in ~he pre~erred embodiment, when there i8 no cas~ette 302 in place, all three outputs are logical ones, and thi~ signal is used to indicate that no ca95ette ha~ been inst~lled or that the cassette 302 i8 i~propQrly in~talled.
It will therefore be appreciated that the USQ 0~ the three ca~sett~ identifying $ndicia 148, 150, and 152 allow thQ
gensration of three di~ital cassette identi~ying signals which ar~ supplied ~rom the optical sensor module 670 to th~
microprocea~or (not shown) to identi~y the particular typa o~
cas6Qtte which is installed. By using this cassette identifying ~y~tem, inappropriata usa o~ an installed casset~e and/or improper cas3ette installation may be prevented.
It i~ desirable to provide an indication that the a~embled cassQtte 302 has been properly installed on the main pu~p unit, with th~ latching mechanism properly closed. Thi~ occurs when the slids lock 560 is pushed fully back again~t the rear of the cas~ettQ guide 510. This is accompll~h~.d bv slidl~ ~ s~f~
latch 240 ~ully into the assembled cassette 302, with the tab 257 on tha slide latch 240 fitting in~o the notch 564 on thQ ~lide locX 560 to drive the ~lide lock 560 back, thereby also latching the ~aws assembly 360 onto the piston asqembly 2~0.

~n lndication o~ latching 15 provided throuyh u~e o~ the optical light source 682 and the optical light sensor 684 on the bottom o~ the optical sensor module 670. When the ~lide lock 560 is in it~ loading or forward po~ition 3hown in Figure 99, the bevel 570 on tha optical sen~or module 670 i~ ad~acent the optical light source 682 and the optical light ~ensor 684 on the bottom o~ tho optical sensor module 670, a~ shown in Figur~ 105 and 10~. The presence of the bevel 570 reflects th~ light co~ing from th~ optical light souroe 682 to the righ~, away rrO~ ~h~
optical light sensor 684, thereby preventing a latch closed sign~l. When the slide lock 560 i3 pu~hed ~ully bacX to its closed or rear mo~t position shown in Figure ~00, the bev~l 570 on the optical sensor module 670 iB not adjacen th~ optical light ~ource 6~2 and the optical light sen~or 684 on the bottom o~ the optical sensor module 670, as ~een in Figure 107. Rather, a reflective surface 567 installed on the flat b~tto~ o~ t~a rectangular aonnecting seg~ent 566 o~ the ~lide lock 560 re~lects light from the opticzl light source 682 into the optical light sensor 684, thereby generating a latch closed ~ignal. The r~lective sur~ace 567 aets as a mirror, and may be a ~oil segment which i~, for example, hot stamped into the rectangular connecting segment 566 or adhesively secured to the bottom of ~he rectangular connecting segment 566.
Additional confirmation that the slide lock 560 was closed ~5 with an assembled cassette 302 in place may be obtained by veri~ying the cassette identifying indicia, a~ described abov~.
In order to result in an absolutely positlve confi~mation that a cassett~ i8 proPerly instal.led and that the ~lid~ ~ k ~50 ~
the closed position, the preferred embodiment will require corract ~ignals from both the optical light sen30r 684, and from the optical light sensors 692, 694, and 696.
One o~ the essential functions of the sy~tem t~ to enabl~
the detaction of air in the fluid lin~ of ~he sy~te~. The 131qO65 preferred embodiment for the air-in line detection (AILD) system o~ the present invention is ~hown in Figure 108, and includss the recsssed lens portion 138 in tha assembled ca~s~tte 302, and a pair o~ sen~or ~lement , namely the optical light sourc~ 698 and thQ optical light sensor 700 in the optical ~ensor module 670.
The r~cessed lens portion 138 i~ an optical vi~wing ar~a ~n the fluid pathway through the a~sembled ca~setta 30~, and in the pre~erred embodiment shown in Figure 108 i3 an in~erted pri~m.
Th~ reces~ed lens portion 138 in any e~bodim~nt also includes a ~ocusing lens, indicated generally at 697. Th~ optical light sourGe 69~ and the optical ligh~ sensor 700 ar~ both mounted in the optical sQn~or module ~70 below the rece~sed pris~atic lens portion 138 in thQ installed ca~sette 302.
The optic~ of the system of Flgur~ 108 mak2s u~e o~ the propertia~ of light a~ it moves from one media to a less dense media, and i9 a "reverse reflected" configuration. When air is in the rluid chann~l, the light ~rom ths optical light source ~9~
follows the pa~h ~hown in Figure l.0~, re~lecting off of one bottom Qide o~ the receRRed prismatic lens portion 138 onto the other, and th~nce downward to the optical li~ht sensor 700. Even if the upper ~urfaces of the recessed prismatic lens portion 138 are wetted with a fluid film, total internal reflection still occurs. When fluid i~ in ths channel, the light re~racts through the recessed prismatic len~ portion 138 into the fluid. If the fluid i~ clear, the light passes through the liquid to 170, where it i8 either ab~orbed by t~e valve dlaphragm 170 or the retainer cap 190, or pa~seR through both the valve diaphragm 170 and the retainer cap 190. Accordin~l~, the valve diaphraqm 170 maY be clear, AbRorptive of light, or may scatter the light, not returnin~ enough light to the optical light sQnSor 700 to generate a signal indicatlve of air being in the fluid path. If the valve diaphragm 170 i9 clear, then the r~tainer cap 190 may be clear, absorpt~v~ of ligh~, or may scatter th~ llght, again not returning enough light to the optiaal lighk sensor 700 to genQrate a signal ind$cativa of air being in the ~luid path. If th~ fluid iB opaque, the light is absorbed by the flutd. In any event, the light does not return to the photodetector. Whak little re~lection of light may occur will bs small compared to thQ air cas~.
Mat~rial requirements of the preferred embodim~nt ~hown in Figur~ 108 are that the cassette body 100 bQ ~ad~ o~ clear mat~rial, that the valve diaphragm 170 be mad~ o~ ~aterial which i clear, absorptive to light, or effectively scatters light. I~
the valve diaphragm 170 is clear, the retainer cap 190 must then ba ~ade of material which is clear, absorptiv~ to light, or effectively ~catters light. In su~maryl the fluid channel in the assembled ca~sette 302 i5 de~igned ~o that with the pre~ence of 15 air in the fluid channel, light sent by the optical light source 698 will be detected by the optical l.ight sensor 700. with fluid contained in the fluid channel, l.ittls or no light will be detected, irrespe¢tiv2 of tha clarity or opaqueness of the fluid.
It will th~re~ora be appreciated ky those skilled in the art that air ~labble~ ~n the llne may b~ easily d~t~cted with the apparatus dlscu~sed above.
There are three alternate embodiments to the arrangement illustrated $n Figure 108. Firqt, in Figure 109, a reflective surface 702 is installed on the side o~ the notch 680 in thQ
optical sensor module 670 oppo~ite the optical light source 698 and th~ optical light sensor 700. The recessed len~ portion 138 in this e~bodiment is V-shap~d, with light be$ng directed from th~ bottom of the V. The materials of the cassette body 100, the ~ e diaphragm 170, an~ the retainer cap 190 ar~ a~l clear.
When a clear fluid is contained in the fluid pathway, light fro~
the optical light source 698 will refract through to the reflective surface 702, and return to the optical light sensor 700, givlng a high signal. When air is present in thQ ~luid ~ 76-pathway, the light from the optical lighk source 698 will re~lect o~ of the ~ecessed lens portion 138 without pa~sing therethrou~h, thereby not reaching the optical lighk sen~or 700.
However, when liplds are contained in tha ~luid pathway, the light will refract through the rece~sed lens portion 138 and be absorbe~ by the lipids, giving a signal indicativ~ o~ air in the fluid pathway. It will thereby be appreciated that the arrangement shown in Figuro 109 is suitablQ ~or u~e with claar fluid~ only.
10Re~erring nex~ ~o Figure 110, a ~urthex variation i3 lllu~trat~d which U~QS a V shaped channal, with tha botto~ o~ th~
V being ~lat. Light i8 directed from the opt~cal light source 698, whlch is mounted on the top o~ the notch 680 in the optical sensor module 670, directly opposit~ th~ optical llght sensor 700 15on the bottom of the notch 680 in the optical sen or module 670.
Tha materials of the cassette body 100, the valve diaphra~m 170, and the ratainer cap 190 are again clear. It will at onc~ be appreciated that the signal received by ths opt$cal light sensor 700 will b~ low ~ox lipids ~n th~ fluid pathway, and high ~or clear ~luid~ in the ~luid pathway. When air is pres~nt in the ~luid pathway, some of the light will re~lect off of the side~ of the V, not reaching the optical light sensor 700, while some of the light will pass through the flat bottom of the V, reaching the sptical light sensor 700. There~ore, for air a medium level 25signal will be received. The system of Figure 110 is a~cordingly a three level system, and not digital.
Referring next to Figure 111, a third variation is illustrated which uses a V-shaped recessed lens portion 138, with llght being directed from the top o~ the V. In this embodiment, 30~ha optical light source 698 and the optical light sensor 700 are mounted on the top of the notch 680 in the optical sensor module ~70, rather than on the bottom. The materials o~ the cassette body 100, the valve diaphragm 170, and ~he retainer cap 190 are again all clear. The signal received by the optical light sensor 700 wlll be high. with air in the fluid pathway, low with clear liguids in the fluid pathway, and genarally medium with lipids contain~d in the fluid pathway. The system o~ Figur~ 111 is a three l~vel ~ystam like the system o~ Figure 110, but the optics o~ the ~y~tem o~ Figure 110 are superio.r to the o~tic~ o~ the 8y8t2m of Figura 111.
Rererring next to Figures 115 and 116, the operation o~ the praasurQ transducer system, which is the ~ub~ct o~ the above-10 id~nti~i2d application entitlad "Pressure Diaphraym ~or aMedication Infusion Sy~te~,'~ ~ay be di3cu~sed. As may be seen, the pre~aure diaphragm 182 contacts the botto~ o~ th~ pressure transducer 660, which is flat. Additionally, th~ pre~sur~
diaphragm 182 does not contact the press~ra plateau 130 Qither on the top or on the sides thereof, ~aking the movament of thQ
pressure diaphragm 182 hlghly accurata and sen~itive.
The pressure transducer 660 ha~ a thin stainles~ steel diaphragm 710 at the bottom thereo~. The diaphragm 710 is ~upported ~ro~ the edge~ by a stainle!ss steel housing 712, which hou~ing 712 contains therein a passageway 714 leading to the squaxe segment 664. The squar~ segment 664 contains a senqor element ~not ~hown in detail) communicating with the passageway 714, which sensor element is a standard sili~on piezoresistive whaatstone bridge type device 716. The passageway 714 i5 filled with silicone o~l to communicate pressure on tha diaphrag~ 710 to the ~ilicon piezoresistive wheatstone bridge type device 716.
It will be appreciated by thos~ skilled in the art that the ~luid pres~ure within the assembled cassette 302 will be communicated through the pressure diaphragm 182 and the diaphrag~
710 to th~ silicone oil in the passageway 714, and theraby to the silicon piezoresistive wheats~one bridge type device 716, which provide~ an alectrical indication of prassure on the leads 666.

~ccordingly, presqure may b~ mea~ured to provid~ an indication of downstre~m ooclu~ion, pumping, fluid pre~ure, etc.
Through the above discussion of thQ entire system, it will be appreciated that the present invention provide~ a uniquQ alr-in-line detQction system for use wit~ a dispo~abl~ cas~ettQ which is mounted onto a main pump unit. The ~ystem of the present invention not only retains all of the advantage3 o~ infu~ion devicQs known in the past, but also provids~ a number o~
additional advantages and improvement~. Th2 air-in-line detection ~stem o~ the present invention can de~ect air bubble~
in th~ ~luid line of a diRposable cas~tto near th# output end o~
tho cassette, after the pumping operation ha3 be~n performed.
Th~ sy~tQm i~ capable of accurately and ~fectively doteating air bubble~ ln any typ~ of ~luid which may be infused, wh~thQr the ~luid i~ clear or opaquo.
O~her additional features are includad in the design of ~hs cass~tte and the main pump unit making up th~ air-in-lin2 deteation syst~m. Two of these features are the ability to deteGt air bubbles whether the flow rat~ of the ~luid in the 2Q ca~s~tt~ is ~ast or slow, and the ability to detect air in the ~luid lina even when the interior of the fluid lin~ remain~
wetted with fluid. In addition to being able to detect air in the ~luid line, the system i~ quite accurate, and present~ a high degree o~ re~istance to false alarms. No previously known medication in~usion system include~ an air-in-line detection ~ystem which comes close to the system of the present invention.
De~pite the inclusion of the aforesaid features, the system of the present invention utilizes a minimum number of parts. all o~ which parts are of inexpensive construction, yet which afford the assembled cassetta a high degree of accuracy. The system of the present invention is therefore able to compete economically with known compe~ing systems, and it provides an ease o~ use rivaling the best of competing systems. The sys~em accomplishes --7g--all these ob~ects in a manner which ratains and enhancss the advantages of r~liability, durability, and ~afety o~ operation, without lncurrlng any r~l~tive dlsadvantage. The present inv~ntion therefore results in a superlor medication in~u~ion ~y~tem having a numbar o~ ~ldv~ntage~ which maka tho sy~t~m a hlghly da~irable alternativo to syst~m~ pre3ently available.
Although an exsmplary ambodiment of tha present invontion ha~ baen shown and de~cribed, it will b~ apparant to tho~e havlng ordinary skill in the art that a number o~ change~, modifications, or altaration~ to the invention a~ dQ cribed hersin may be mads, non~ of whlch dep~rt ~rom the spir$t o~ th~
prasent ~nv~ntion. All such ohanges, modi~ications, and alteration should therefore be seen as within the 8copa Or the presQnt invention.

-7`9a -

Claims (18)

  1. WHAT IS CLAIMED IS, i. A system for detecting the presence of air bubbles in fluid passing through a disposable cassette installed on a main unit in a medication infusion system or the like, comprising:
    an optical receiving module mounted on said main unit;
    optical signal source means for providing a light beam, said optical signal source means being located in said optical receiving module;
    optical signal sensor means for receiving said light beam, said optical signal sensor means also being located in said optical receiving module:
    a fluid channel located in said disposable cassette, said fluid channel having a first wall, said fluid channel also having a second wall located opposite said first wall, fluid passing through said disposable cassette passing through said fluid channel in an area between said first wall and said second wall, said first wall being transparent to said light beam from said optical signal source means, said second wall being absorptive of light of the type provided by said optical signal source means, said first wall of said fluid channel being located adjacent said optical receiving module when said disposable cassette is installed on said main unit; and an optical viewing area located in said first wall, one side of said optical viewing area being located over said optical signal source means, the other side of said optical viewing area being located over said optical signal sensor means, said optical viewing area being arranged and configured to reflect said light beam from said optical signal source means onto said optical signal sensor means when said area of said fluid channel has air therein, said light beam from said optical signal source means passing through said optical viewing area when said area of said fluid channel has fluid therein.
  2. 2. A system as defined in Claim 1, wherein said optical signal source means is a light emitting diode.
  3. 3. A system as defined in Claim 1, wherein said optical signal sensor means is a phototransistor.
  4. 4. A system as defined in Claim 1, wherein said one side of said optical viewing area is aligned over said optical signal source means in said optical receiving module when said disposable cassette is installed onto said main unit, and other side of said optical viewing area is aligned over said optical signal sensor means in said optical receiving module when said disposable cassette is installed onto said main unit.
  5. 5. A system as defined in Claim 1, wherein light which passes through said optical viewing area is absorbed.
  6. 6. A system as defined in Claim 5, wherein said second wall is made of material which absorbs light, said light which passes through said viewing area being absorbed by said second wall if the fluid pasting through said disposable cassette is clear, said light which passes through said viewing area being absorbed by the fluid passing through said disposable cassette is the fluid passing through said disposable cassette is opaque.
  7. 7. A system as defined in Claim 6, wherein said optical viewing area comprises:
    a focusing element for focusing said light beam from said optical signal source means; and a light directing element for allowing said light beam to pass therethrough into said area between said first wall and said second wall if no air bubble is passing through said area, said light directing element reflecting said light beam back through said focusing element onto said optical signal sensor means.
  8. 8. A system as defined in Claim 7, wherein said focusing element and said light directing element are integrally manufactured.
  9. 9. A system as defined in Claim 7, wherein said light directing element comprises:
    an inverted triangular prism which is oriented with one of its lateral faces facing said optical signal source means and said optical signal sensor means.
  10. 10. A system as defined in Claim 9, wherein said inverted triangular prism has the other two lateral faces disposed in said area of said fluid channel, said light beam from said optical signal source means being directed onto one of said other two lateral faces of said inverted triangular prism, said light beam passing through said one of said other two lateral faces of said inverted triangular prism if no air bubble is contained in said area of said fluid channel, said light beam being reflected off of said one of said other two lateral face of said inverted triangular prism onto the other of said other two lateral faces of said inverted triangular prism, and from said other of said other two lateral faces of said inverted triangular prism to said optical signal sensor means is an air bubble is contained in said area of said fluid channel.
  11. 11. A system as defined in Claim 1, wherein said optical viewing area comprises:
    an essentially triangular lens member located on the side of said first wall facing said second wall, one lateral aide of said lens member located against said side of said first wall facing said second wall, the other two lateral sides of said lens member thereby being disposed in said area in said fluid channel, one of said other two lateral sides of said lens member being located over said optical signal source means, the other of said other two lateral sides of said lens member being located over said optical signal sensor means, said other two lateral sides of said lens member being arranged and configured to reflect said light beam from said optical signal source means off of said one of said other two lateral sides of said lens member onto said other of said other two lateral sides of said lens member and onto said optical signal sensor means when said area of said fluid channel has air therein, said light beam from said optical signal source means passing through said one of said other two lateral sides of said lens member when said area of said fluid channel has fluid therein.
  12. 12. A system as defined in Claim 11, wherein the side of said first wall away from said second wall includes thereon a focusing element to direct said light beam onto said triangular lens member.
  13. 13. A system as defined in Claim 1, wherein said area of said fluid channel is sufficiently small to cause any air bubble passing through said fluid channel to contact said optical viewing area.
  14. 14. A system as defined in Claim 1. additionally comprising:
    a housing for said cassette, said housing having said fluid channel including said first wall recessed therein, the top of said fluid channel being open; and diaphragm means for sealably covering said open top of said fluid channel.
  15. 15. A system as defined in Claim 14, wherein said housing is made of clear material and said diaphragm means is made of light-absorbing material.
  16. 16. A system for detecting the presence of air bubbles in fluid passing through a disposable cassette installed on a main unit in a medication infusion system or the like, comprising:
    an optical receiving module mounted on said main unit;
    optical signal source means for providing a light beam, said optical signal source means being located in said optical receiving module;
    optical signal sensor means for receiving said light beam, said optical signal sensor means also being located in said optical receiving module:
    a fluid channel located in said disposable cassette, said fluid channel having a first wall, said fluid channel also having a second wall located opposite said first wall, fluid passing through said disposable cassette passing through said fluid channel in an area between said first wall and said second wall, said first wall being transparent to said light beam from said optical signal source means, said second wall being absorptive of light of the type provided by said optical signal source means, said first wall of said fluid channel being located adjacent said optical receiving module when said disposable cassette is installed on said main unit; and an essentially triangular lens member made of transparent material, said lens member located on the side of said first wall facing said second wall, one side of said lens member located against said side of said first wall facing said second wall, the other two sides of said lens member thereby being disposed in said area in said fluid channel, one of said other two sides of said lens member being located over said optical signal source means, the other of said other two sides of said lens member being located over said optical signal sensor means, said other two sides of said lens member acting as a prism element to reflect said light beam from said optical signal source means off of said one of said other two sides of said lens member onto said other of said other two sides of said lens member and onto said optical signal sensor means when said area of said fluid channel has air therein, said light beam from said optical signal source means passing through into said said area of said fluid channel one of said other two sides of said lens member when said area of said fluid channel has fluid therein, said light beam when entering said area of said fluid channel either being absorbed by the fluid contained therein, or being absorbed by the light-absorptive material of said second wall.
  17. 17. A system for detecting the presence of air bubbles in fluid passing through a disposable cassette installed on a main unit in a medication infusion system or the like, comprising:

    optical signal source means for providing a light beam, said optical signal source means on said main unit;
    optical signal sensor means for receiving said light beam, said optical signal sensor means also on said main unit;
    a fluid channel located in said disposable cassette, said fluid channel having a transparent first wall which first wall is located adjacent said optical receiving module when said disposable cassette is installed on said main unit, said fluid channel also having a light-absorptive second wall located opposite said first wall, fluid passing through said disposable cassette passing through said fluid channel in an area between said first wall and said second wall; and a lens member having two sides extending from the side of said first wall facing said second wall into said area in said fluid channel, said two sides of said lens member being arranged and configured to reflect said light beam from said optical signal source means off of said one of said two sides of said lens member onto said other of said two sides of said lens member and onto said optical signal sensor means when said area of said fluid channel has air therein, said light beam from said optical signal source means passing through said one of said two sides of said lens member when said area of said fluid channel has fluid therein.
  18. 18. A method of detecting the presence of air bubbles in fluid passing through a disposable cassette installed on a main unit in a medication infusion system or the like, comprising:
    mounting an optical receiving module on said main unit;
    for providing a light beam from an optical signal source means, said optical signal source means being located in said optical receiving module;

    receiving said light beam with an optional signal sensor means, said optical signal sensor means also being located in said optical receiving module;
    locating a fluid channel in said disposable cassette, said fluid channel having a first wall, said fluid channel also having a second wall located opposite said first wall, fluid passing through said disposable cassette passing through said fluid channel in an area between said first wall and said second wall, said first wall being transparent to said light beam from said optical signal source means, said second wall being absorptive of light of the type provided by said optical signal source means, said first wall of said fluid channel being located adjacent said optical receiving module when said disposable cassette is installed on said main unit; and installing an essentially triangular lens member on the side of said first wall facing said second wall, one side of said lens member located against said side of said first wall facing said second walls the other two sides of said lens member thereby being disposed ion said area in said fluid channel, one of said other two sides of said lens member being located over said optical signal source means, the other of said other two sides of said lens member being located over said optical signal sensor means, said other two sides of said lens member being arranged and configured to reflect said light beam from said optical signal source means off of said one of said other two sides of said lens member onto said other of said other two sides of said lens member and onto said optical signal sensor means when said area of said fluid channel has air therein, said light beam from said optical signal source means passing through said one of said other two sides of said lens member when said area of said fluid channel has fluid therein.
CA000584382A 1987-12-01 1988-11-29 Air-in-line detector for a medication infusion system Expired - Fee Related CA1319065C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US128,121 1987-12-01
US07/128,121 US5006110A (en) 1987-12-01 1987-12-01 Air-in-line detector infusion system

Publications (1)

Publication Number Publication Date
CA1319065C true CA1319065C (en) 1993-06-15

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US (1) US5006110A (en)
EP (1) EP0319277B1 (en)
JP (1) JP2695878B2 (en)
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US5064412A (en) 1989-09-05 1991-11-12 Pacesetter Infusion, Ltd. Ultrasonic air-in-line detector for a medication infusion system
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DE3879895D1 (en) 1993-05-06
EP0319277B1 (en) 1993-03-31
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DE3879895T2 (en) 1993-11-04
JPH01303158A (en) 1989-12-07
EP0319277A1 (en) 1989-06-07

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