CA1293153C - Parenteral solution diaphragm pump - Google Patents
Parenteral solution diaphragm pumpInfo
- Publication number
- CA1293153C CA1293153C CA000613073A CA613073A CA1293153C CA 1293153 C CA1293153 C CA 1293153C CA 000613073 A CA000613073 A CA 000613073A CA 613073 A CA613073 A CA 613073A CA 1293153 C CA1293153 C CA 1293153C
- Authority
- CA
- Canada
- Prior art keywords
- check valve
- valve
- diaphragm
- outlet
- inlet
- 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 - Lifetime
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES 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
- A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
- A61M1/02—Blood transfusion apparatus
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES 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
- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/14—Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
- A61M5/142—Pressure infusion, e.g. using pumps
- A61M5/14212—Pumping with an aspiration and an expulsion action
- A61M5/14224—Diaphragm type
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES 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
- A61M2205/00—General characteristics of the apparatus
- A61M2205/12—General characteristics of the apparatus with interchangeable cassettes forming partially or totally the fluid circuit
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES 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
- A61M2205/00—General characteristics of the apparatus
- A61M2205/12—General characteristics of the apparatus with interchangeable cassettes forming partially or totally the fluid circuit
- A61M2205/128—General characteristics of the apparatus with interchangeable cassettes forming partially or totally the fluid circuit with incorporated valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K15/00—Check valves
- F16K15/14—Check valves with flexible valve members
- F16K15/144—Check valves with flexible valve members the closure elements being fixed along all or a part of their periphery
-
- Y—GENERAL 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
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T137/00—Fluid handling
- Y10T137/7504—Removable valve head and seat unit
- Y10T137/7559—Pump type
Abstract
ABSTRACT OF THE DISCLOSURE
A diaphragm pump cassette for use with a pumping mechanism. The cassette comprises a pumping chamber and a check valve assembly communicating with the pumping chamber. The check valve assembly includes a first check valve and a second check valve. Each check valve includes a valve seat, flexible valve diaphragm and a movable valve seating mechanism for locating the diaphragm on the valve seat. The valve diaphragms are unseated with respect to the valve seat prior to mounting the pump cassette on the pumping mechanism whereby fluid may flow freely through the check valve. The valve seating mechanism of the first check valve includes a further mechanism, independent of the pumping mechanism, for manually opening and closing the first check valve.
A diaphragm pump cassette for use with a pumping mechanism. The cassette comprises a pumping chamber and a check valve assembly communicating with the pumping chamber. The check valve assembly includes a first check valve and a second check valve. Each check valve includes a valve seat, flexible valve diaphragm and a movable valve seating mechanism for locating the diaphragm on the valve seat. The valve diaphragms are unseated with respect to the valve seat prior to mounting the pump cassette on the pumping mechanism whereby fluid may flow freely through the check valve. The valve seating mechanism of the first check valve includes a further mechanism, independent of the pumping mechanism, for manually opening and closing the first check valve.
Description
This application is a divisional of Canadian Patent Application No. 523,150 filed November 17, 1986.
Field of Invention This invention relates to a diaphragm pump casse-tte for use wi-th a pumping mechanism and particularly to a disposable pumping cassette which is associated with a parenteral solution or intravenous pump as utilized in a fluid delivery system.
Background of the invention Pumping system for the delivery of fluid intravenously or intra~arterially are well known in the prior art and are in widespread daily use in hospitals throughout the world. These systems are commonly used for the intravenous or intra-arterial delivery of such fluids as glucose solutions and blood plasma, and for the delivery of drugs, all at controlled delivery rates based on the patient's need, and in the case of drugs, the drug concentration being delivered.
The oldest and most commonly used fluid delivery system relies on a gravity feed. Pumping systems offer advantages of mobility and positive control of flow rates by pump motor control. The prior art pumps include both peristaltic pumps and positive displacement pumps. Both have the disadvantage o high cost and high operating expense. Portable units consume large amounts of power and require large, heavy battery packs, and the disposable pumping 30~ chambers are complex and expensive.
DESCRIPTION OF THE PRIOR ART
Pumps which squeeze or apply a positive fluid displacement member against a tube or pumping chamber segments and control fluid flow to and from the pumping chamber with further positively controlled tube pinching members including peristaltic pumps and 9~S~
similar systems are described in U.S. Patents 4,199,307, 4,273,121, 4,290,346, and 4,515,589, for example. A combination of a peristaltic pump and a back pressure monitor is described in U.S. Patent No.
4,460,355.
Syringe pumps are described in U.S. Patent No.
3,739,943 using a disposable hypodermic syringe as the pumping chamber and with a back pressure monitor.
A syringe pump is also disclosed in U.S. Patent No.
4,515,591.
A piston pump with a radially segmented spring element is described in U.S. Patent No. 4,276,004.
piston pumps with the piston or equivalent displacement member covered with an elastic rubber barrier to isolate the pump chamber from the drive ` members are described in U.S. Patents 4,140,118, 4,336,800, 4,453,931, 4,453,932, 4,457,753, and 4,519,732. Most piston pumps have inlet and outlet check valves. One or both of the inlet and outlet check valves in U.S. Patents 4,126,132 and 4,468,222 are open during a fluid priming step prior to loading the pumping cassette into the operating housing, and are automatically activated into an operational position by the insertion of the cassette into the housing. In U.S. Patent 4,468,222, the disposable cassette comprises an elastic diaphragm defining one wall of the pumping chamber and inlet and outlet valve members of a one-piece molded construction.
Diaphragm pumps usually have resilient diaphragm members which are connected to a drive member, and are usually combined with inlet and outlet check valves as described in U.S. Patents 2,812,716 and 2,954,738. These pumps lack the accuracy required for parenteral solution deliver because the diaphragm flexure during the positive pressure and negative pressure cycles alter the volume of the pumping chamber in a non-linear function which cannot be adequa-tely compensated with programing. Diaphragm pumps comprising concen-tric cylindrical segments isolated from the pumping~ chamber with a rubber diaphragm are described in U.S. Patent 1,923,970 and 3,200,757. However, these high friction diaphragms are unsuitable for use in parenteral solution delivery systems, and do not have the advantages of the unitary segmented diaphragm of the pump of this invention.
Segmented diaphragms have also been used in valve structures such as are described in U.S.
Patents 1,034,323, 1,229,860, 4,078,580, 4,208,031 and 4,231,287. A segmented diaphragm has been used in a camera lens positioning system in U.S. Patent 3,677,161 and in a pressure controller in U.S. Patent 4,364,386.
SUMMARY AND OBJECTS OF THE INVEWTION
A disposable diaphragm pump cassette comprises a flexible disphragm member comprising hinged, rigid plates hingedly mounted on a inflexible plate and opposed to a pumping chamber surface to form a pumping chamber. The pump includes a check valve means comprising movable circular plates integrally connected with the inflexible plate by flexible, extendable webs. The flexible diaphragm member can comprise at least three inflexible diaphragm plates with edges in a common plane, each diaphragm plate having at least two straight diaphragm plate hinge edges. Each diaphragm plate hinge edge is adjacent to and aligned with a second diaphragm plate hinge edge of an adjacent diaphragm plate. The adjacent edges of each diaphragm plate hinge edge and second diaphragm plate hinge edge are attached together by a flexible hinge strip.
-~ A preferred inlet check valve comprises an inlet check valve plate, a valve seat means opposing the check valve plate, and a flexible diaphragm disk with a central flow passageway between the inlet cneck valve pla..e and the valve seat means. In this embodiment, the flexible inlet diaphragm disk has an inlet side facing the valve seat and communicating with a fluid inlet, and an ou-tlet side facing the inlet check valve plate and communicating with the pumping chamher. The inlet check valve plate is a check valve activation membex which, by pressing the flexible inlet diaphragm disk against the valve seat means, activates the inlet check valve.
A preferred outlet check valve comprises an outlet check valve plate including a valve seat means, an outlet check valve chambe.r opposing the valve seat means, and a flexible outlet diaphragm disk with a central flow passageway between the outlet check valve plate and the outlet check valve chamber. In this embodiment, the flexible outlet diaphragm disk has an inlet face facing the valve seat means and communicating with the pumping chamber and an outlet face facing the outlet check valve chamber and communicating with a fluid outlet. The outlet check valve plate is a check valve activation member which, by pressing the valve seat means against the flexible outlet diaphragm disk, activates the outlet check valve.
One object of this invention is to provide a parenteral solution pump with a low cost disposable cassette comprising the pumping chambex and valve structures made of few inexpensive, easily molded parts, which can be assembled and jointed wi.th a minimum of labor and a low defect rate.
Anothe.r object of this invention is the provision of a high accuracy pump which requires a small amount of energy fox operation, and which is easy to prime, install and opera~e.
According to the above objects and fxom a further broad aspect of the pxesent lnvention, there is provided a diaphxagm pump cassette for use with a pumping mechanism comprising a pumping chamber, and a check valve means communicating with the pumping chamber. The check valve means includes a first check valve and a second check valve. ~ach check valve includes a valve seat, a flexible valve diaphragm, and movable valve seating means for locating the diaphragm on the valve seat.
The valve diaphragms are unseated with respect to the valve seat prior to mounting the pump cassette on the pumping mechanism whereby fluid may flow freely through the check valve means There is further provided a casse-tte back pl~te wherein the valve seating means is a check valve plate attached to the back plate by a flexible hinge means.
The above objects of this invention will be readily apparent in the description of the invention presented hereinafter.
Brlef Description of the Drawings Fig. 1 is a schematic representation of a parenteral pump delivery system.
Fig. 2 is a partial cross-sectional representation of the pump of this invention positioned in engagement wlth the drive system and motor housing.
Fig. 3 is an exploded cross-sectional representation of one embodiment of the disposable cassette elements prior to assembly.
Fig. 4 is a fragmentary detailed cross-sec-tional view of the swage closure elements of the front and back plates shown in Figuxe 3 during assembly.
s~
Fig. 5 is a fragmentary detailed cross-sectional view of the swage closure of the front and back plates shown in Figure 3 afte.r assembly.
Fig. 6 is a back view of the back plate shown in Figure 3.
Fig. 7 is a front view of the back plate shown in Fig. 3.
Fig. 8 is a cross-sectional view of the baek plate shown in Fig. 7, taken along the line 8-8.
Fig. 9 is a back view of the front clbsure plate shown in Fig. 3.
Fig. 10 is a partial cross-sectional view of the cassette assembly showing the pump diaphragm and inactive check valves during priming.
Fig. 11 is a partial cross-sectional view of the cassette assembly of Fig. 10 showing the check valves after activation.
Fig. 12 is a partial cross-seetional view of the installed cassette assembly of Fig. 10 during the output phase of the pumping cyele.
Fig. 13 is a partial cross-seetional view of the installed cassette assembly of Fig. 10 during the filling phase of the pumping cycle.
Fig. 14 is a partial, fragmented view of the disposable cassette of this invention mounted on the motor housing.
Detailed ~eseription of the Invention The parenteral solution delivery pump of this invention has a low cost, disposable cassette comprising a few molded parts which can be easily assembied. It provides economy in construction and operation. The pump housing and cassette, including power souree and controller, are portable and light in weight.
Fig. 1 is a schematic representation of a parenteral pump delivery system according to this invention. The fluid bag or bottle 2 is suspended on the standard clinical support pole 4. The fluid administration set includes the standard drip chamber 6 and Y-junction 8. The drip chamber can be combined with an optionaldrop monitor 12. The flexible tubing 14 extends to and connects with the pump cassette 16 shown mounted in the pump and controller housing 18.
-The outlet tubing 20 con~ects with the pump cassette 16 and leads to the patient being treated.
Fig. 2 is a partial cross-sectional representation of the pump 16 of this invention posi-tioned in engagement with the motor and controller housing 18 and the drive system enclosed therein.
The DC motor 24 has a drive shaft 26 supported by bearing 28, the distal encl of the drive shaft 26 being connected to a drive wheel 30. The drive wheel 30 has a cam groove 32 in the back face thereof engaged by the cam follower 34 attached to the movable end 36 of the drive beam 38. The opposite end 40 of the drive beam 38 is mounted for pivotal movement around pin 42. The male drive connector 44 with barbs or self-threading threads 45 is attached to a central portion of the drive beam 38, and engages a female receptor 46 integral with the central diaphragm plate on the back plate of the pump cassette 16. The flexible plate diaphragm will be shown in greater detail hereinafter.
The distance of the cam groove 32 from the central axis of the drive shaft 26 varies as the drive shaft rotates, translating the rotary motion of the drive shaft to a reciprocating displacement of the cam follower 34 and cassette drive connector 44.
The drive connector 44 thus imparts a reciprocating motion to the diaphragm plate of which the female drive connector 45 is a part. An annular flexible splash shield 48 is secured to the male drive connec-tor and the surrounding edges of the housing 18 to prevent liquid contaminants from reaching the interior of the housing 18.
5~
Inlet tubing 14 from the liquid source 2 (Flg. 1) is secured to a tubing cornector inlet 50 o~ the ca~sette 16. Outlet tubin~ 20 e~tendin~ to the patient is secured to a tubin~ connector outlet 52 of the cassette.
The cassette 16 is secured to the housing 18 by tabs or ears 54 and 56 extendirlg from the cassette 16 into corresponding grooves defined by retent.ion projections ~0 and 62 e~tending from the front of the hou~ing.
Fig. 3 is an exploded c~os.s-sec:tional repr~sentatio of one embodiment of the fi~.re disposable cassette elemer,ts prior to assembly.
The clispGsable puri~p cassette 1~ comprises a front plate 70, back plate 72, resili.ent inlet,check valve washer 74, resilient outlet check valve washer 76 and Gutlet check valve engaging knob 78. q'he f'ronk plate 70 has an inlet tube c~r.nector 50 consisting of a nipple extension 80 with an inlet fluid ~assageway 8~ for enterin~ and expandi.ng the tubing 14 ~Fig. 1), and a surroundlng annular recess 84 for receiving the tubin~
20 ~all as the tubing is s~.ipped over the nip~le 80. Th~ -inlet pa~ageway 82 communicates with the inlet check val~e inlet 86 and annular inlet check valve cavity 88.
The inlet check valve cavity ~8 surrounds the stationary valve seat element 90. A circular inlet c.~eck valve washer receptor is defi.ned by annu'lar rim 92 for supporting the edges of the check valve washer 74.
Swa~e joint groove 94 and swage projection 9S extend completel~ around the back face edge oP th~ front plate -:~. Pumplng cavity 98 is positioned on the bar,k face oP
the fror.t plate 70 between the inlet check valve elements and the outlet check valve elements~
1.5~
The outlet check valve elements O:e the front plate include the outlet check valve washex receptor defined by the annular groove 100 which surrounds the conical outlet check valve cavity 102. The outlet check valve outlet 104 communicates with the cavity 102 and the outlet flow passageway 106 in ~he outlet tubing nipple extension 108 of the outlet tu~ing connector 52. The nipple 108 is surrounded by an annular tukin~ receptor 110 which receives the outlet tub~ng when it is slipped over the end of the nipple lOa.
The inlet check v~lve washer 74 is a resilient, elastic material in the ~orm o F a disk with a central flow passayeway 112. The outlet check valve washer 76 is a resilient, elastic material in the forr,l of a dis~;
with a central flow passageway 114.
The back check valve plate 72 i5 also of unita~y construction and includes the check ~alv~ activation element3, se~mented pump diap~ragm, and pump dri~e connectcr element. W~ereas the front plate 70 i~ made -20 of rig~ plastic, the back plate is made of a plastic such as polyethylene ~hi~h is essenti~l rigid in thickened portions and flexible and ~.tendable in thinned connectin~ p3~tions.
The thickened, infle~ible ~cL plate 120 surrounds and is connected to the t}:icke~ed, inflexible inlet check valve activ~tion disk 122 by the ~lexible, extendable anr.ular connect ng web 124. The fron~ face of the disk 122 has an anllular raised ridg~ 126. The pump diaphra~m comprises an ~n~lexible central plate 12 integral with the felaale pump drive receptor 46, surrounded by the inflexible back plate 120 and connected thereto by rigid, hin~ed pump segments 130 and 132. Pump segment 130 is connected to the central plate 128 by thirlned, fle~ible hinge pcrtion 134 and to the back plate 120 by the thinnQd, f~exible hinge portion 136. Pump segment 132 is connected to the central plate 128 by thinned, flexible hing~ portion 138 and to the back plate 120 by the thinned, fle~ible hi-nge portion 140.
Outlet check valve e~.e~ents of the bacl: rJlate 72 comprise a ~hr~aded outlet check l~alve activation }:nob rece~tor 142 which is integral with the back F!late 120 and e~rtending outwarcl rearwarcll~ therefrom. The th.ickened, inflexible outlet checlf. valve activation disk 144 is conne;ted to the ~ottcm edge of the ~nob re.ceptor 142 by a thinned, flexi~le, extendable annular web 146.
The circular outlet check valve cavity is defined by circular recess 14~ in the front, central face of the dis~ 144. Annular raised ridge 150 e~:tending from the front face of th~ outlet check valva por~ion of the p].ate 120 secura~ the outlet check valve disk 76 in place when the front and back pieoa5 are joined. Swage joint ridge element 15~ exten;~s from the front face of the periphery of the back plate 72.
Outiet check valve activation knob 78 has a s-ip flange porti.on 160, a threaded cylindri_al portion 1.~
for engagincJ the threaded receptor 14~, and an axi~lly concentric proj~-ction 1~4 for engac~ing the opposing surface of t}le o~tlet ch~ck valve disk 14~ when advanced thereagainst.
Fig. 4 is a fracJmentary ~etail~d eross-ectioral view of the swage closure elements of tl-e fr~t ~nd ba-k plates shown in Figure 3 d~ring assembly, and Fig~ 5 is a view of the swage closure of the front and back plates shown in Fig. 3 after assembly. The swag~ closure groove 94 of the front plate 70 is defined b~ a wall s~
surface 1~8 in the back side of ~he front plata and a ridge 170 haviny a wall surface 172. The opposite side 174 of ~he ridge 170 slopes to fcrm a knlfa-ed~e projection extending from the front plata wh;ch will be swaged to form a secure closure. The bottom of the swage closure groove has sharp edyed sealing ridges 176. Sha~p knlfe-eclged ridges 176 extend tow~rd the opposing face 178 of the swage ciosure ridge 152 of the ~ack plate 72. Swage jcint ridc~e element 152 has a 10 forward face 178 opposin~ the sealing rid~ 176 and sloped sidewalls 1~0 and 182 which engage the corresponding sloped sidew~lls 168 and 172 of the swage closure cjroove in tight corJpression to form a li~uid-tight seal. Swage closure abutment surface 18~.
is parallel to sur ace 178.
In Fig. 5, the cGnlpleted s~age closure joint is shown. The knife-edged ridges fonned of rigid plastic of the front plate are forced into the opposirlg surface 178 of the closure ridge m~de o~ the ~ofter plastic of the back plate under high pre~ure to form a second liquid tight seal. The leading edye of the ridge 170 is swaged over the abutment surface 184 undex high pressure to form a secure engagement which will rigid y retairl the front an~ back plates in permanent engaaement. The - 25 swa~e groove and ridge e~ter.d around the entire periphery of the cassette, and thus form a liquid tight dual seal around the edge of the cassettè. The swa~e closure and seals are re~luired when the materials from which the front and back plates are tormed are incompatible and cannot be securely joined by welding, solvelit bonding, gluing or other standard procedures.
Optimally, the back plate is made of a ~aterial wl-ich is relatively rigid when thicX, and yieldable and fle~ible when in a thin cross-section! Exam~les of such material~ are polyolefins such as low and high dansity polyethylene, optimum mat2rials fo- the back plate. In contrast, the front plate re~.ires a high rigidity and is preferably formed with ABS polymer or the like which cannot be securely bonded to polyethylene. The dual sealed swage closure of this invention joins such t~Jo incom~atible plastics togethe r to for~ a secure unitary construction which will not leak liquid from the inner chamber.
Fig. 6 is a ~ack view of the ~ack F~late shown in Fig. 3, Fig. 7 is a f~ont view of the bac.~ plate, ar.d Fig. ~ is a cross-sectional view of the back plate shown in Fig. 7, taken along t~e line 8-8. In Fig. 6 the overall config~ration of the check valves and diaphragm shown in cross-s~-~tion in Fic. 3 can be seen. The rigid hexagonal diaphra~m plate 128, on which the drive receptor 4G is sap~orted, is ioined to the surr~unding rigid bac~ plate 72 by six rigid trapezoidal plates, the optimum configuration for a p~mp of this size. Each trapezoidal plat~ is jcined to the back plata by a thinned, flexible, yielda~le hinge such as 135 and 140, and is joined to the llex3gonal diaphragm plate 1~8 by a thinned, flexible, yieldable hinye such as 13~ and 13~.
The adjacent edges of adja-ent tra~ezoidal plates are joined by thinned, flexible, yieldable hinyes such as 131 and 133, for exa,~ple. This pattern is repeated with each trapezoidal }~late.
The preferred, flexible diaphragm member has at least three infle~ible diaphragm plates with e~es in a common plane, each diaphrdgm plate having at least two straight diaphragm plate hinge edges. Each diaphragm plate hinge edge is adjacent to and aligned with a e s~
second diaphragm plate hinge edge of an adjacent diaphragm plate. The adjacen-t edges of each i~
diaphra~m plate hinge edge and second diaphragm plate hinge edge are attached together by a fLexible hinge stri~ O~ti.mally, when the first array o:E plates comprises at least three identi.cal plates having identical. edges, the respective .i(~entical ecl~es thereof are ~ositionecl equally di.stant fro~ the axial cen-ter of symmetry. Addi-tionallv, the f.lex.ibl.e member can include a central pl.ate as shown in Fi~.
6, the axial center of the center plate be.i.n~ at the axial center o symmetry. The center plate opt:imally has straight plate edges havin~ the same length, and the plates include an array of p].ates hingedly connect.ed to the straight sides of the center pl.ate.
~ach p.late.in l:he array of plates then has a straight cent.er plate hinge edge positioned adjacent to and aligned with a center plate ed~e and hi.ngedly connected at the center pla-te edqe by a f].exible hinge strip.
In the embodiment illustrated i.n -the draw.ings, a total oE six plates are assemhled in a symmetrical arrav around the axial cen-ter. Tt wi.l.l. be readil.y apparent that the number of plates can be selected as desired, a minimum of three plates bei.ng required ~or operation in the .intended manner. ~he ~lexib].e hi.nge elements are distorted by both fl.exure and st.retching during the movement of the diaphra~m e.lement, and as -t.he number of segments are reduced, greater energy is expended to effect flexure. Stretch distortion of the hinge lncreases toward the center of the diaphragm, and this distortion is increased by reducing the number o~ plates. T.ncreas:in~ t-he num~er of segments increases the flexibl.e hin~e area and reduces the stretchin~ required L5~
for dlaphragm movemen-t, both reducing energy requlrements.
Increasing the hinge width and reducing the thickness of the hinge also inc.reases hinge flexibility and elas-ticity, further reducing energy requirements. E~owever, increasing the number of plates, increasing the relative hinge area and reducing the hinge thickness lncreases non-linear pumping errors.
An important achievement of the flexible plate ......... diaphra~m is the reduction of pumning volu~e variat~ions which are a function of liquid ~ressure.
Liquid pressure rising in the pumping chamher dur.ing a positive pumping s-troke and falling during the filling stroke tends to stretch the di.aphragm, increasing or decreasina the vo~.ume of the pumpin~
chamber, and introducing a non-linear variable in the liquid volume output or input. per stroke. The volume displaced during a positive stroke is thus less than would be calculated by simple displacement, and the volume fi.lled during a fillinq stro~e is less -than would be calculated by a simp.l.e displacement calculation. Because the degree of distortion is a function of the varying pumplng chamber pressures, which is in turn, a function of the pumping rate and outlet valve and line back-press~re, this type of distortion cannot be adequately compensated bv microcomputer contro]. adjus~ments and seriously impai.rs pumping accuracy.
This effect is very pronounced with the .~].e~ible diaphragm pumps known pri.or to this invent.ion.
Piston pumps, while avoiding this prob].em, use more power and reauire a more comp].ex construction to prevent leakage from the pumping chamber around the p.i.ston.
With the plate dia~hraqnl construction o~ this invention, however, the increased pressure in the pumping chamber does not s~ynificantly ~lex the plate elements, and a more linear relationship between displacement and delivered ~olume is achieved. With the hinged plate diaphra~n of this invention, diaph~a~
flexure is resisted ~y the relatively inflexihle plates. Only the hinge areas will fiex. Thus, the areas subje_t tG flexure are minimized, conslstent with the designed power and pressure restraints of a portable, battery operated unit, for exam~le. The diaphra~m o~ Figure 1, having a central plate and six ~qual segments, represe}lts a studied compromise of these factors, and is believecl to represent a preferr~d configuration for use with the pump configuration for pare.~teral solution delivery shown in the drawinys.
The plate bearing the flexible plate components and the individual p;ate element of ~he diaphraq~ are preferabl~f relatively rigid to achieve maximum a~-curQcy. This can be achieved by bending ricJid plate ele~ents to a flexible sheet. For example, a rela~ively rigid pol~t~mer can be bonded to a flexible, elastic polymer, co.~bining the rigidity and flexibilit~
d~sired. In a preferred embodiment of this invent on, elements of the front plate bearing the hinged plate diaphragm are formed from a single, homogeneous sheet of plastic. Rigidity is achieved by thickness and flexibility by thinness. Polyolefirl plastics such as polyethylene can be used for thi.s construction, for example. In this embodiment, the rigid plates and ~he flexible hinges are integral parts of a single unit.
Correspollding checX valve elements can be similarly -~7-fol~ed in Fame ~he she~t o plastl~. The bac~: plate can be made of a suitable rigi~ plastic such as ABS po~ r.
~ eferring to Fig. 7 and Fig. 8, the front surface of the back plate 72 is shown. Within the swage ridge 152 extending around the periphery of the bacK plate are positioned the check valves 122 and 144 and the grooves and ridges which together with the Gorresponding grooves and ridyes of the front late fo.~ the valve and p~mpin~
cavities and fluid flow passageways in the cassette.
The inlet check valve face 122 is surroun~ed by circular ridge ~00 which presse.s the inlet check valve dis~ 7~
(Fig. 3) acJainst the ed~e of the inlet check valve disk recepto_ 92 of the front ~late. This is surrounded by a circular liquid flow channel groove 202 leading to inl~' channels 204 an~ 200. The inlet channel 206 leads toward the pumping cham~er defined by the ridges 208 ar.d 210 surrounding the inner surrace 212 of the pu~np diaphragm. Groove 214 haviny ~n inlet ~nd 216 constitutes an optional air-in-line fluid flow passageway, directing the fluid along a narrow ~assas-eway of precise dimensions and returning the f'uid to exit at 218. If this type of air-in-line d~tector is to be omitted, this passageway is omitted entirely. The fluid is then direc~ed by a ~assac~e~tay in the front plate to the'inlet 2Z0 o~ the outlet check'valve passaseway ~22 leading to the outlet check valv~ cha~ber 144. The ridge 224 surrounding the check valve chan~ber ,144 press~s the outlet che~X ~alve disk -J6 (~i~. 3) against the edge of the outlet chec~ val~e rec~ptor lOC
o~ the front plate.
Fig. 9 is a bacX view of the front closure plate shown in Fi~. 3. The flow passa~eways in the cassette are formed by a pattern of aligne~ ~rooves or channels in t~.e back side of the front cloc:ure plate shown in Fig. 9 and ti~e cor-responding, engaqing front sur~ace of the back plate shown in Fi~. 7. The grooves or channels, together with the flat opposing surface of the oppcsite plate, define enclosed passageways, and references to features shown in Fig. 7 and in Fig. 9 are made in the followir.g description.
The fou- tabs or mounting fianyes 54 are positioned with one at each corner Gf the casset-te. T~le sw~ge groove 94 and swage rid~e ~6 extend around the entire periphery of the front plate. The circular configuration cf the inlet check valve structure with inlét passageway 86 and the concentric valve seat 90 and check valve disk receptor 92 a~e positioned at the upper 15 portiorl of the front plate positioned to oppose the respective elements of the bac}: plate. l'he valve seat 90 comprises a raised circular ridge for abutting the inlet checX valve w~sher or diaphragm 74 The outlet chec~ valve elements are con~-entric; the inlet passageway 104, valve cavity defin n~ cone 102 and the outlet cileck valve disk receptor are formed in the back surface of the frort plate.
The peri~eter of the hexagonai diaphrasm purlp ~hamber 230 is defined by six s]ope~ edge sur aces 232, 234, 236, 23~, 240 and 242. Fluid is further confined within the pump cham~er by engaging ridges and grooves on five sidas of the pum~ chamber, parallel to the sloped ed~e surfaces, ~nd positior.ed adjacent to the sloped surfaces exterior to the pump chamber. Fluid retention groove 244 is positioned to engage the corresponding fluid retention ridge 210 (Fig. 7). Fluid retention groove ~46 extending arourd four sides of the hexagon is positioned to enga~e the corresponding fluid retention rid~e 208. The close proximity O r the pressure swage seal Gf the edge 248 closely adja~ent to and bordering the sixth Fide 240 of the sloped edge sur~ace provides an effective fluid retention barrier on the si~th side of the pump chamber hexagon.
The pump chamber inlet groove 250 is positioned at the inlet end of the caC.sQtte to communicate w th the end 207 of the in]f~t groove ~05, for ~irec,ion of fluid flow from the inlet check valve chamber directly to the pumping chamber. The end of the pump outlet groove 252 is positioned at the inlet: end of the cassette to co~unicate with the inlet end 216 of the optional ~ir-in-line detection passa~eway 214 (Fig. 7). The fluid flow passageway 254 directs fluid flow to the vicinity of the outlet checX valve at the outlet end of the cassette. The nlet end 25G of the fluid outflow passageway 254 co~unicates with the outlet er.d 218 of the optional air-in-l~ne detectol passagew~y. The outlet end 258 of the fluid outflow passageway 254 communicates with the inlet end 220 of the outlet check valv~ inlet passa~eway 222 (Fig. 7). If the groove 216-218 is omitted, the groove ends 252 an~ 256 commLnicate directly, an~ uid flows dire_tly from the outlet 252 to the inlet 2~6 of the fluid outflow passageway 25~. -Fig. 10 is a partial cross-sectional view of the cassette assembly showing the pump diaphragm and inactive ch~c~ valves d~ring priming, and Fig. 11 i5 a view of the cassette assembly showlng the check valve~
after activation. Initially, the knob 78 is rotate~ to press the element 144 against che diaphra~m disk 76 to activate the chec~ valve, the position shown in Fig.
11. This closes the outlet valve, and in this position, -2a-the ~ump cassette can ~erform the functions of a traditional roller clamp, preventing fluid flGw thrGugh the system until desired. After connecting the inlet tubing 14 to the inlet tubing nipple 80 and to the liquid source, and after connecting the outlPt tubing 20 to the outlet tu~in~ nipple, the outlet check valve is deactivated (opened) ~y rotati.ng the. knob 78 to the pOSitiOIl sho~n in Eig. lG. ~ic~id then flows ~ro~ the source 2 through the inlet tubing 14, inlet ~assageway 82 and into the inlet check va.lve inlet 86. ~he inlet check valve washer or diaphragm 74 is space~ from the sea~ 90 of the inlet chec~ valve, and fluid passes ket~een the ridge 90 and the opposing surface of the inlet check valve diaphragm and through the central opening 112 of the check valve diaphraym. The fluid then passes across the face of the inlet check valve actuator and to the outlet passageway 204. The fluid is tllen directed to the diaphragm pump chamher, displacing air in the pump chamber until it is filled with fluid.
The fluid then continues to pass th~ough the opt.onal air-in-line detector loop 21~ ig. 7) and passageway 254 until it reaches the outlet check valve chamber, erAterin~ throu~Jh passag~way 22~. Since th~ outlet chec~
valve diaphragm opening 114 is urobstructed, ~luid i.s free to pass througll the opening 114, into the outlet check valve chamber 10~, throuc~h the out:let pa~sageway 106 and t:o the outlet tubing 20. Air is thus displaced from t~e pumping unit, and i-~ is ~/rimed for operation.
The knGb 7~ ic. than turr.ed tc activat~ !depress) the outlet check-valve, moving the certral dis}c 144 i.nto contact with the outlet check valve diaphra~m and .
blocking the central opening 114 in the outlet check valve diaphragm 76. The thinned continuous we~ portion 15~
1~6 stretches without breaking, permitting movement of the cencral disk 1~4 without detachment from the back plate or loss of integrity of outlet check valve. The final position is ch~wn in Fig. 11. Tne primed, set pump cassette of this invention is then mounted on the motor drive housin~ in the position shown in ~ig. 2, the self-threading motor drive member 44 securely mounted in the drive rece~tor 14~.
The pumping cassette connected to the motor drive is shown in Fig. 11, with the exception that the motor drive housing is not shown. In being mounted in the motor drive housin-~, the inlet check valve me~ber 122 is depressed by a protruding surface of the housing. The central disk 122 is pressed toward the inlet check valve diaphraym 74, the circular ridge 200 pressing the diaphragm 74 inward and against the raised circular ridge of the valve seat gO. Thus the inlet check valve is activated by the operation o pressiny the pumping cassette against a raised portion of the motor drive 20 housing.
It will be readily apparen~ to a person skilled in the art that t'ie outlet check valve can also be constructed to ~le a~tivated by a portion of the motor drive housir.g rather than a separ~te knob ~8, o-r that 25 the inlet check valve can be constru~ted to be separately activated by a control ~nob rather than the motor housing surface, and both of these alterna~ive embodiments are included within this inventicn.
However, the embodiment shown in ~iy. 10 and ~1 is the 30 preferred embodiment. After pumping is terminated, the pumping cassette can be disconnected from the motor drive and removed from the motor drive housing. The inlet check valve wi]l be inactivated to the open position upon return of the inlet check valve elements to the initial prin,ing position shown in Fig. 10. The knob 78 can be rotated to a positicn which establishes the desired gravity flow rate, assuming the fluid source is positioned at a higher elevation such as shown in Fig. 1.
Fig. 12 is a partial cross-sectional view of the installed cassette assembly of Fig. 10 during the output phase of the pumping cycle, and Fig. 13 shows the installed cassette assembly during the filling phase of the pumping cycle. D~ring the output phase, the motor drive element 44 advances toward the pumping cassette, moving the face 212 of the central diaphragm segment 128 toward the opposing face of the pump chamber cavity, thus reducing the volur.le of the pumping chamber. This movement is permitted by the flexure (with some stretching) of the hinge segments 134, 13~, 138 and 140 and the corresponding movement of the rigi~ plate segments 130 and }32. The combination of the rigid ~late segments and small area of the hi~ges provides an~
prevents any signlficant distortion of the pumping chan~er vol~me due to flexure of the pumping surfaces in the manner of resilient pump diaphrasms. The pump of this invention thuc combines the uniclue features o~ a diaphra~m pump with the preci~ion of a piston pump.
With the pump configuration of this invention, an output volume which is a function of the pumping displacement is achieved, permitting the control precision o~ a piston pump with the simple construction and energy 30 efficiency of a diaphra~n pump.
The fluid expressed from the pumping chamber is expelled through the outlet passageway 252 and eventually to the outlet chec]c valve. The fluid i.?~9.~i53 -23~
pressure between the element 144 and the outlet check valve diaphra~n 76 displaces th~ diaphragm surface from the surface of the element 144, exposing the diaphra~m passageway 114. Liquid passes through opening 114 and the outlet passageway 106 ~o tubing 20. Reverse flow of liquid to the source is prevented by the construction of the inlet check valve. The volume 121 defin~d by the surface of the actuator 122, the ridge 2C0 and the inlet check valve diaphragm 74 is in direct communication with the pumping chan~er, and the increased pressure of the output phase of the pump pressles the diaphragm 74 securely against the seat 90, preventing fluid escape to the inlet passageway.
The reverse flGw of the fill~ng ph~se of the pump is shown in Fig. 13. Reverse motion of the pump element 44 pulls the central rigid diaphragm segment 128 away from the opposing surface of the front plate, increasin~ the volume of the pumping chambGr. ~hP rigid, hin~ed plates 130 and 132 follow, the plate structure berldin~ about the hinges 134, 136, 138 and 14G. The rigid plate construction again achieves a volume change which is a direct function of the displacement of the actuator 44, achieving a precise filling volume. The volume is not affected significantly by the dif~erence in pump chamber pressure and atmospher~c pressure.
The pressure in the pumping ~hamber and chamber 121 during the filling phase falls below the relative pressure in the inlet conduit 8~ and inlet check valve inlet 86. The inlet fluid pressure displaces the face of the inlet check valve diaphragm 74 away from the valve seat 90, permitting liquid flow through the inlet check valve to the passageway 204 and to the pumping chamber. The pressure in the outlet flow passageway 105 and outlet check valve chambe- 104 also exceeùs the pressure in the pumping cham~er during the filling ~hase, pressing the outlet check valve diaphragm 76 firmly against the surface of the outlet check valve element 144. Reverse flow of l.iquid from the outlet conduit 20 during the filling phase is thus prevented.
The outlet check valve assembly ~rovides an additionzl safety feature. If the c.assette 16 becomes dislodged from the housing 18, the outlet chec~. valve actuator 144 remains in the for~ard position, pressing agair.st the disk 76 and preventing any further fluid flow to the patient.
Fig. 1~ is a partial, fr~gmented vie~J of the disposakle cassette of this invention mounted on the motor housing. The mounting tabs or ears 5~ and 56 the front plate (Fig. 9) are engaged with mounting groove 250 (shown as dotted lines) defined by the upper mountiny flanges 60 ~nd 61 and mounting groova.25~ by cloc~;wise rotation of th6 cassette 16. The rotation is termi~lated b-~ the abutl,lent of the ~abs with the ends of the grcove, 254 and 256. The drive elem.en~ 4~ is fixed against rotation about its axis. Rotation o~ the cassette to engage the tabs 54 and 56 with the ~ounting flanges 60 and 61 threa~s the recept~r 46 ont.~ the barbs 25 or self-threading screw threads 45 on the surface of the drive element 44.
Field of Invention This invention relates to a diaphragm pump casse-tte for use wi-th a pumping mechanism and particularly to a disposable pumping cassette which is associated with a parenteral solution or intravenous pump as utilized in a fluid delivery system.
Background of the invention Pumping system for the delivery of fluid intravenously or intra~arterially are well known in the prior art and are in widespread daily use in hospitals throughout the world. These systems are commonly used for the intravenous or intra-arterial delivery of such fluids as glucose solutions and blood plasma, and for the delivery of drugs, all at controlled delivery rates based on the patient's need, and in the case of drugs, the drug concentration being delivered.
The oldest and most commonly used fluid delivery system relies on a gravity feed. Pumping systems offer advantages of mobility and positive control of flow rates by pump motor control. The prior art pumps include both peristaltic pumps and positive displacement pumps. Both have the disadvantage o high cost and high operating expense. Portable units consume large amounts of power and require large, heavy battery packs, and the disposable pumping 30~ chambers are complex and expensive.
DESCRIPTION OF THE PRIOR ART
Pumps which squeeze or apply a positive fluid displacement member against a tube or pumping chamber segments and control fluid flow to and from the pumping chamber with further positively controlled tube pinching members including peristaltic pumps and 9~S~
similar systems are described in U.S. Patents 4,199,307, 4,273,121, 4,290,346, and 4,515,589, for example. A combination of a peristaltic pump and a back pressure monitor is described in U.S. Patent No.
4,460,355.
Syringe pumps are described in U.S. Patent No.
3,739,943 using a disposable hypodermic syringe as the pumping chamber and with a back pressure monitor.
A syringe pump is also disclosed in U.S. Patent No.
4,515,591.
A piston pump with a radially segmented spring element is described in U.S. Patent No. 4,276,004.
piston pumps with the piston or equivalent displacement member covered with an elastic rubber barrier to isolate the pump chamber from the drive ` members are described in U.S. Patents 4,140,118, 4,336,800, 4,453,931, 4,453,932, 4,457,753, and 4,519,732. Most piston pumps have inlet and outlet check valves. One or both of the inlet and outlet check valves in U.S. Patents 4,126,132 and 4,468,222 are open during a fluid priming step prior to loading the pumping cassette into the operating housing, and are automatically activated into an operational position by the insertion of the cassette into the housing. In U.S. Patent 4,468,222, the disposable cassette comprises an elastic diaphragm defining one wall of the pumping chamber and inlet and outlet valve members of a one-piece molded construction.
Diaphragm pumps usually have resilient diaphragm members which are connected to a drive member, and are usually combined with inlet and outlet check valves as described in U.S. Patents 2,812,716 and 2,954,738. These pumps lack the accuracy required for parenteral solution deliver because the diaphragm flexure during the positive pressure and negative pressure cycles alter the volume of the pumping chamber in a non-linear function which cannot be adequa-tely compensated with programing. Diaphragm pumps comprising concen-tric cylindrical segments isolated from the pumping~ chamber with a rubber diaphragm are described in U.S. Patent 1,923,970 and 3,200,757. However, these high friction diaphragms are unsuitable for use in parenteral solution delivery systems, and do not have the advantages of the unitary segmented diaphragm of the pump of this invention.
Segmented diaphragms have also been used in valve structures such as are described in U.S.
Patents 1,034,323, 1,229,860, 4,078,580, 4,208,031 and 4,231,287. A segmented diaphragm has been used in a camera lens positioning system in U.S. Patent 3,677,161 and in a pressure controller in U.S. Patent 4,364,386.
SUMMARY AND OBJECTS OF THE INVEWTION
A disposable diaphragm pump cassette comprises a flexible disphragm member comprising hinged, rigid plates hingedly mounted on a inflexible plate and opposed to a pumping chamber surface to form a pumping chamber. The pump includes a check valve means comprising movable circular plates integrally connected with the inflexible plate by flexible, extendable webs. The flexible diaphragm member can comprise at least three inflexible diaphragm plates with edges in a common plane, each diaphragm plate having at least two straight diaphragm plate hinge edges. Each diaphragm plate hinge edge is adjacent to and aligned with a second diaphragm plate hinge edge of an adjacent diaphragm plate. The adjacent edges of each diaphragm plate hinge edge and second diaphragm plate hinge edge are attached together by a flexible hinge strip.
-~ A preferred inlet check valve comprises an inlet check valve plate, a valve seat means opposing the check valve plate, and a flexible diaphragm disk with a central flow passageway between the inlet cneck valve pla..e and the valve seat means. In this embodiment, the flexible inlet diaphragm disk has an inlet side facing the valve seat and communicating with a fluid inlet, and an ou-tlet side facing the inlet check valve plate and communicating with the pumping chamher. The inlet check valve plate is a check valve activation membex which, by pressing the flexible inlet diaphragm disk against the valve seat means, activates the inlet check valve.
A preferred outlet check valve comprises an outlet check valve plate including a valve seat means, an outlet check valve chambe.r opposing the valve seat means, and a flexible outlet diaphragm disk with a central flow passageway between the outlet check valve plate and the outlet check valve chamber. In this embodiment, the flexible outlet diaphragm disk has an inlet face facing the valve seat means and communicating with the pumping chamber and an outlet face facing the outlet check valve chamber and communicating with a fluid outlet. The outlet check valve plate is a check valve activation member which, by pressing the valve seat means against the flexible outlet diaphragm disk, activates the outlet check valve.
One object of this invention is to provide a parenteral solution pump with a low cost disposable cassette comprising the pumping chambex and valve structures made of few inexpensive, easily molded parts, which can be assembled and jointed wi.th a minimum of labor and a low defect rate.
Anothe.r object of this invention is the provision of a high accuracy pump which requires a small amount of energy fox operation, and which is easy to prime, install and opera~e.
According to the above objects and fxom a further broad aspect of the pxesent lnvention, there is provided a diaphxagm pump cassette for use with a pumping mechanism comprising a pumping chamber, and a check valve means communicating with the pumping chamber. The check valve means includes a first check valve and a second check valve. ~ach check valve includes a valve seat, a flexible valve diaphragm, and movable valve seating means for locating the diaphragm on the valve seat.
The valve diaphragms are unseated with respect to the valve seat prior to mounting the pump cassette on the pumping mechanism whereby fluid may flow freely through the check valve means There is further provided a casse-tte back pl~te wherein the valve seating means is a check valve plate attached to the back plate by a flexible hinge means.
The above objects of this invention will be readily apparent in the description of the invention presented hereinafter.
Brlef Description of the Drawings Fig. 1 is a schematic representation of a parenteral pump delivery system.
Fig. 2 is a partial cross-sectional representation of the pump of this invention positioned in engagement wlth the drive system and motor housing.
Fig. 3 is an exploded cross-sectional representation of one embodiment of the disposable cassette elements prior to assembly.
Fig. 4 is a fragmentary detailed cross-sec-tional view of the swage closure elements of the front and back plates shown in Figuxe 3 during assembly.
s~
Fig. 5 is a fragmentary detailed cross-sectional view of the swage closure of the front and back plates shown in Figure 3 afte.r assembly.
Fig. 6 is a back view of the back plate shown in Figure 3.
Fig. 7 is a front view of the back plate shown in Fig. 3.
Fig. 8 is a cross-sectional view of the baek plate shown in Fig. 7, taken along the line 8-8.
Fig. 9 is a back view of the front clbsure plate shown in Fig. 3.
Fig. 10 is a partial cross-sectional view of the cassette assembly showing the pump diaphragm and inactive check valves during priming.
Fig. 11 is a partial cross-sectional view of the cassette assembly of Fig. 10 showing the check valves after activation.
Fig. 12 is a partial cross-seetional view of the installed cassette assembly of Fig. 10 during the output phase of the pumping cyele.
Fig. 13 is a partial cross-seetional view of the installed cassette assembly of Fig. 10 during the filling phase of the pumping cycle.
Fig. 14 is a partial, fragmented view of the disposable cassette of this invention mounted on the motor housing.
Detailed ~eseription of the Invention The parenteral solution delivery pump of this invention has a low cost, disposable cassette comprising a few molded parts which can be easily assembied. It provides economy in construction and operation. The pump housing and cassette, including power souree and controller, are portable and light in weight.
Fig. 1 is a schematic representation of a parenteral pump delivery system according to this invention. The fluid bag or bottle 2 is suspended on the standard clinical support pole 4. The fluid administration set includes the standard drip chamber 6 and Y-junction 8. The drip chamber can be combined with an optionaldrop monitor 12. The flexible tubing 14 extends to and connects with the pump cassette 16 shown mounted in the pump and controller housing 18.
-The outlet tubing 20 con~ects with the pump cassette 16 and leads to the patient being treated.
Fig. 2 is a partial cross-sectional representation of the pump 16 of this invention posi-tioned in engagement with the motor and controller housing 18 and the drive system enclosed therein.
The DC motor 24 has a drive shaft 26 supported by bearing 28, the distal encl of the drive shaft 26 being connected to a drive wheel 30. The drive wheel 30 has a cam groove 32 in the back face thereof engaged by the cam follower 34 attached to the movable end 36 of the drive beam 38. The opposite end 40 of the drive beam 38 is mounted for pivotal movement around pin 42. The male drive connector 44 with barbs or self-threading threads 45 is attached to a central portion of the drive beam 38, and engages a female receptor 46 integral with the central diaphragm plate on the back plate of the pump cassette 16. The flexible plate diaphragm will be shown in greater detail hereinafter.
The distance of the cam groove 32 from the central axis of the drive shaft 26 varies as the drive shaft rotates, translating the rotary motion of the drive shaft to a reciprocating displacement of the cam follower 34 and cassette drive connector 44.
The drive connector 44 thus imparts a reciprocating motion to the diaphragm plate of which the female drive connector 45 is a part. An annular flexible splash shield 48 is secured to the male drive connec-tor and the surrounding edges of the housing 18 to prevent liquid contaminants from reaching the interior of the housing 18.
5~
Inlet tubing 14 from the liquid source 2 (Flg. 1) is secured to a tubing cornector inlet 50 o~ the ca~sette 16. Outlet tubin~ 20 e~tendin~ to the patient is secured to a tubin~ connector outlet 52 of the cassette.
The cassette 16 is secured to the housing 18 by tabs or ears 54 and 56 extendirlg from the cassette 16 into corresponding grooves defined by retent.ion projections ~0 and 62 e~tending from the front of the hou~ing.
Fig. 3 is an exploded c~os.s-sec:tional repr~sentatio of one embodiment of the fi~.re disposable cassette elemer,ts prior to assembly.
The clispGsable puri~p cassette 1~ comprises a front plate 70, back plate 72, resili.ent inlet,check valve washer 74, resilient outlet check valve washer 76 and Gutlet check valve engaging knob 78. q'he f'ronk plate 70 has an inlet tube c~r.nector 50 consisting of a nipple extension 80 with an inlet fluid ~assageway 8~ for enterin~ and expandi.ng the tubing 14 ~Fig. 1), and a surroundlng annular recess 84 for receiving the tubin~
20 ~all as the tubing is s~.ipped over the nip~le 80. Th~ -inlet pa~ageway 82 communicates with the inlet check val~e inlet 86 and annular inlet check valve cavity 88.
The inlet check valve cavity ~8 surrounds the stationary valve seat element 90. A circular inlet c.~eck valve washer receptor is defi.ned by annu'lar rim 92 for supporting the edges of the check valve washer 74.
Swa~e joint groove 94 and swage projection 9S extend completel~ around the back face edge oP th~ front plate -:~. Pumplng cavity 98 is positioned on the bar,k face oP
the fror.t plate 70 between the inlet check valve elements and the outlet check valve elements~
1.5~
The outlet check valve elements O:e the front plate include the outlet check valve washex receptor defined by the annular groove 100 which surrounds the conical outlet check valve cavity 102. The outlet check valve outlet 104 communicates with the cavity 102 and the outlet flow passageway 106 in ~he outlet tubing nipple extension 108 of the outlet tu~ing connector 52. The nipple 108 is surrounded by an annular tukin~ receptor 110 which receives the outlet tub~ng when it is slipped over the end of the nipple lOa.
The inlet check v~lve washer 74 is a resilient, elastic material in the ~orm o F a disk with a central flow passayeway 112. The outlet check valve washer 76 is a resilient, elastic material in the forr,l of a dis~;
with a central flow passageway 114.
The back check valve plate 72 i5 also of unita~y construction and includes the check ~alv~ activation element3, se~mented pump diap~ragm, and pump dri~e connectcr element. W~ereas the front plate 70 i~ made -20 of rig~ plastic, the back plate is made of a plastic such as polyethylene ~hi~h is essenti~l rigid in thickened portions and flexible and ~.tendable in thinned connectin~ p3~tions.
The thickened, infle~ible ~cL plate 120 surrounds and is connected to the t}:icke~ed, inflexible inlet check valve activ~tion disk 122 by the ~lexible, extendable anr.ular connect ng web 124. The fron~ face of the disk 122 has an anllular raised ridg~ 126. The pump diaphra~m comprises an ~n~lexible central plate 12 integral with the felaale pump drive receptor 46, surrounded by the inflexible back plate 120 and connected thereto by rigid, hin~ed pump segments 130 and 132. Pump segment 130 is connected to the central plate 128 by thirlned, fle~ible hinge pcrtion 134 and to the back plate 120 by the thinnQd, f~exible hinge portion 136. Pump segment 132 is connected to the central plate 128 by thinned, flexible hing~ portion 138 and to the back plate 120 by the thinned, fle~ible hi-nge portion 140.
Outlet check valve e~.e~ents of the bacl: rJlate 72 comprise a ~hr~aded outlet check l~alve activation }:nob rece~tor 142 which is integral with the back F!late 120 and e~rtending outwarcl rearwarcll~ therefrom. The th.ickened, inflexible outlet checlf. valve activation disk 144 is conne;ted to the ~ottcm edge of the ~nob re.ceptor 142 by a thinned, flexi~le, extendable annular web 146.
The circular outlet check valve cavity is defined by circular recess 14~ in the front, central face of the dis~ 144. Annular raised ridge 150 e~:tending from the front face of th~ outlet check valva por~ion of the p].ate 120 secura~ the outlet check valve disk 76 in place when the front and back pieoa5 are joined. Swage joint ridge element 15~ exten;~s from the front face of the periphery of the back plate 72.
Outiet check valve activation knob 78 has a s-ip flange porti.on 160, a threaded cylindri_al portion 1.~
for engagincJ the threaded receptor 14~, and an axi~lly concentric proj~-ction 1~4 for engac~ing the opposing surface of t}le o~tlet ch~ck valve disk 14~ when advanced thereagainst.
Fig. 4 is a fracJmentary ~etail~d eross-ectioral view of the swage closure elements of tl-e fr~t ~nd ba-k plates shown in Figure 3 d~ring assembly, and Fig~ 5 is a view of the swage closure of the front and back plates shown in Fig. 3 after assembly. The swag~ closure groove 94 of the front plate 70 is defined b~ a wall s~
surface 1~8 in the back side of ~he front plata and a ridge 170 haviny a wall surface 172. The opposite side 174 of ~he ridge 170 slopes to fcrm a knlfa-ed~e projection extending from the front plata wh;ch will be swaged to form a secure closure. The bottom of the swage closure groove has sharp edyed sealing ridges 176. Sha~p knlfe-eclged ridges 176 extend tow~rd the opposing face 178 of the swage ciosure ridge 152 of the ~ack plate 72. Swage jcint ridc~e element 152 has a 10 forward face 178 opposin~ the sealing rid~ 176 and sloped sidewalls 1~0 and 182 which engage the corresponding sloped sidew~lls 168 and 172 of the swage closure cjroove in tight corJpression to form a li~uid-tight seal. Swage closure abutment surface 18~.
is parallel to sur ace 178.
In Fig. 5, the cGnlpleted s~age closure joint is shown. The knife-edged ridges fonned of rigid plastic of the front plate are forced into the opposirlg surface 178 of the closure ridge m~de o~ the ~ofter plastic of the back plate under high pre~ure to form a second liquid tight seal. The leading edye of the ridge 170 is swaged over the abutment surface 184 undex high pressure to form a secure engagement which will rigid y retairl the front an~ back plates in permanent engaaement. The - 25 swa~e groove and ridge e~ter.d around the entire periphery of the cassette, and thus form a liquid tight dual seal around the edge of the cassettè. The swa~e closure and seals are re~luired when the materials from which the front and back plates are tormed are incompatible and cannot be securely joined by welding, solvelit bonding, gluing or other standard procedures.
Optimally, the back plate is made of a ~aterial wl-ich is relatively rigid when thicX, and yieldable and fle~ible when in a thin cross-section! Exam~les of such material~ are polyolefins such as low and high dansity polyethylene, optimum mat2rials fo- the back plate. In contrast, the front plate re~.ires a high rigidity and is preferably formed with ABS polymer or the like which cannot be securely bonded to polyethylene. The dual sealed swage closure of this invention joins such t~Jo incom~atible plastics togethe r to for~ a secure unitary construction which will not leak liquid from the inner chamber.
Fig. 6 is a ~ack view of the ~ack F~late shown in Fig. 3, Fig. 7 is a f~ont view of the bac.~ plate, ar.d Fig. ~ is a cross-sectional view of the back plate shown in Fig. 7, taken along t~e line 8-8. In Fig. 6 the overall config~ration of the check valves and diaphragm shown in cross-s~-~tion in Fic. 3 can be seen. The rigid hexagonal diaphra~m plate 128, on which the drive receptor 4G is sap~orted, is ioined to the surr~unding rigid bac~ plate 72 by six rigid trapezoidal plates, the optimum configuration for a p~mp of this size. Each trapezoidal plat~ is jcined to the back plata by a thinned, flexible, yielda~le hinge such as 135 and 140, and is joined to the llex3gonal diaphragm plate 1~8 by a thinned, flexible, yieldable hinye such as 13~ and 13~.
The adjacent edges of adja-ent tra~ezoidal plates are joined by thinned, flexible, yieldable hinyes such as 131 and 133, for exa,~ple. This pattern is repeated with each trapezoidal }~late.
The preferred, flexible diaphragm member has at least three infle~ible diaphragm plates with e~es in a common plane, each diaphrdgm plate having at least two straight diaphragm plate hinge edges. Each diaphragm plate hinge edge is adjacent to and aligned with a e s~
second diaphragm plate hinge edge of an adjacent diaphragm plate. The adjacen-t edges of each i~
diaphra~m plate hinge edge and second diaphragm plate hinge edge are attached together by a fLexible hinge stri~ O~ti.mally, when the first array o:E plates comprises at least three identi.cal plates having identical. edges, the respective .i(~entical ecl~es thereof are ~ositionecl equally di.stant fro~ the axial cen-ter of symmetry. Addi-tionallv, the f.lex.ibl.e member can include a central pl.ate as shown in Fi~.
6, the axial center of the center plate be.i.n~ at the axial center o symmetry. The center plate opt:imally has straight plate edges havin~ the same length, and the plates include an array of p].ates hingedly connect.ed to the straight sides of the center pl.ate.
~ach p.late.in l:he array of plates then has a straight cent.er plate hinge edge positioned adjacent to and aligned with a center plate ed~e and hi.ngedly connected at the center pla-te edqe by a f].exible hinge strip.
In the embodiment illustrated i.n -the draw.ings, a total oE six plates are assemhled in a symmetrical arrav around the axial cen-ter. Tt wi.l.l. be readil.y apparent that the number of plates can be selected as desired, a minimum of three plates bei.ng required ~or operation in the .intended manner. ~he ~lexib].e hi.nge elements are distorted by both fl.exure and st.retching during the movement of the diaphra~m e.lement, and as -t.he number of segments are reduced, greater energy is expended to effect flexure. Stretch distortion of the hinge lncreases toward the center of the diaphragm, and this distortion is increased by reducing the number o~ plates. T.ncreas:in~ t-he num~er of segments increases the flexibl.e hin~e area and reduces the stretchin~ required L5~
for dlaphragm movemen-t, both reducing energy requlrements.
Increasing the hinge width and reducing the thickness of the hinge also inc.reases hinge flexibility and elas-ticity, further reducing energy requirements. E~owever, increasing the number of plates, increasing the relative hinge area and reducing the hinge thickness lncreases non-linear pumping errors.
An important achievement of the flexible plate ......... diaphra~m is the reduction of pumning volu~e variat~ions which are a function of liquid ~ressure.
Liquid pressure rising in the pumping chamher dur.ing a positive pumping s-troke and falling during the filling stroke tends to stretch the di.aphragm, increasing or decreasina the vo~.ume of the pumpin~
chamber, and introducing a non-linear variable in the liquid volume output or input. per stroke. The volume displaced during a positive stroke is thus less than would be calculated by simple displacement, and the volume fi.lled during a fillinq stro~e is less -than would be calculated by a simp.l.e displacement calculation. Because the degree of distortion is a function of the varying pumplng chamber pressures, which is in turn, a function of the pumping rate and outlet valve and line back-press~re, this type of distortion cannot be adequately compensated bv microcomputer contro]. adjus~ments and seriously impai.rs pumping accuracy.
This effect is very pronounced with the .~].e~ible diaphragm pumps known pri.or to this invent.ion.
Piston pumps, while avoiding this prob].em, use more power and reauire a more comp].ex construction to prevent leakage from the pumping chamber around the p.i.ston.
With the plate dia~hraqnl construction o~ this invention, however, the increased pressure in the pumping chamber does not s~ynificantly ~lex the plate elements, and a more linear relationship between displacement and delivered ~olume is achieved. With the hinged plate diaphra~n of this invention, diaph~a~
flexure is resisted ~y the relatively inflexihle plates. Only the hinge areas will fiex. Thus, the areas subje_t tG flexure are minimized, conslstent with the designed power and pressure restraints of a portable, battery operated unit, for exam~le. The diaphra~m o~ Figure 1, having a central plate and six ~qual segments, represe}lts a studied compromise of these factors, and is believecl to represent a preferr~d configuration for use with the pump configuration for pare.~teral solution delivery shown in the drawinys.
The plate bearing the flexible plate components and the individual p;ate element of ~he diaphraq~ are preferabl~f relatively rigid to achieve maximum a~-curQcy. This can be achieved by bending ricJid plate ele~ents to a flexible sheet. For example, a rela~ively rigid pol~t~mer can be bonded to a flexible, elastic polymer, co.~bining the rigidity and flexibilit~
d~sired. In a preferred embodiment of this invent on, elements of the front plate bearing the hinged plate diaphragm are formed from a single, homogeneous sheet of plastic. Rigidity is achieved by thickness and flexibility by thinness. Polyolefirl plastics such as polyethylene can be used for thi.s construction, for example. In this embodiment, the rigid plates and ~he flexible hinges are integral parts of a single unit.
Correspollding checX valve elements can be similarly -~7-fol~ed in Fame ~he she~t o plastl~. The bac~: plate can be made of a suitable rigi~ plastic such as ABS po~ r.
~ eferring to Fig. 7 and Fig. 8, the front surface of the back plate 72 is shown. Within the swage ridge 152 extending around the periphery of the bacK plate are positioned the check valves 122 and 144 and the grooves and ridges which together with the Gorresponding grooves and ridyes of the front late fo.~ the valve and p~mpin~
cavities and fluid flow passageways in the cassette.
The inlet check valve face 122 is surroun~ed by circular ridge ~00 which presse.s the inlet check valve dis~ 7~
(Fig. 3) acJainst the ed~e of the inlet check valve disk recepto_ 92 of the front ~late. This is surrounded by a circular liquid flow channel groove 202 leading to inl~' channels 204 an~ 200. The inlet channel 206 leads toward the pumping cham~er defined by the ridges 208 ar.d 210 surrounding the inner surrace 212 of the pu~np diaphragm. Groove 214 haviny ~n inlet ~nd 216 constitutes an optional air-in-line fluid flow passageway, directing the fluid along a narrow ~assas-eway of precise dimensions and returning the f'uid to exit at 218. If this type of air-in-line d~tector is to be omitted, this passageway is omitted entirely. The fluid is then direc~ed by a ~assac~e~tay in the front plate to the'inlet 2Z0 o~ the outlet check'valve passaseway ~22 leading to the outlet check valv~ cha~ber 144. The ridge 224 surrounding the check valve chan~ber ,144 press~s the outlet che~X ~alve disk -J6 (~i~. 3) against the edge of the outlet chec~ val~e rec~ptor lOC
o~ the front plate.
Fig. 9 is a bacX view of the front closure plate shown in Fi~. 3. The flow passa~eways in the cassette are formed by a pattern of aligne~ ~rooves or channels in t~.e back side of the front cloc:ure plate shown in Fig. 9 and ti~e cor-responding, engaqing front sur~ace of the back plate shown in Fi~. 7. The grooves or channels, together with the flat opposing surface of the oppcsite plate, define enclosed passageways, and references to features shown in Fig. 7 and in Fig. 9 are made in the followir.g description.
The fou- tabs or mounting fianyes 54 are positioned with one at each corner Gf the casset-te. T~le sw~ge groove 94 and swage rid~e ~6 extend around the entire periphery of the front plate. The circular configuration cf the inlet check valve structure with inlét passageway 86 and the concentric valve seat 90 and check valve disk receptor 92 a~e positioned at the upper 15 portiorl of the front plate positioned to oppose the respective elements of the bac}: plate. l'he valve seat 90 comprises a raised circular ridge for abutting the inlet checX valve w~sher or diaphragm 74 The outlet chec~ valve elements are con~-entric; the inlet passageway 104, valve cavity defin n~ cone 102 and the outlet cileck valve disk receptor are formed in the back surface of the frort plate.
The peri~eter of the hexagonai diaphrasm purlp ~hamber 230 is defined by six s]ope~ edge sur aces 232, 234, 236, 23~, 240 and 242. Fluid is further confined within the pump cham~er by engaging ridges and grooves on five sidas of the pum~ chamber, parallel to the sloped ed~e surfaces, ~nd positior.ed adjacent to the sloped surfaces exterior to the pump chamber. Fluid retention groove 244 is positioned to engage the corresponding fluid retention ridge 210 (Fig. 7). Fluid retention groove ~46 extending arourd four sides of the hexagon is positioned to enga~e the corresponding fluid retention rid~e 208. The close proximity O r the pressure swage seal Gf the edge 248 closely adja~ent to and bordering the sixth Fide 240 of the sloped edge sur~ace provides an effective fluid retention barrier on the si~th side of the pump chamber hexagon.
The pump chamber inlet groove 250 is positioned at the inlet end of the caC.sQtte to communicate w th the end 207 of the in]f~t groove ~05, for ~irec,ion of fluid flow from the inlet check valve chamber directly to the pumping chamber. The end of the pump outlet groove 252 is positioned at the inlet: end of the cassette to co~unicate with the inlet end 216 of the optional ~ir-in-line detection passa~eway 214 (Fig. 7). The fluid flow passageway 254 directs fluid flow to the vicinity of the outlet checX valve at the outlet end of the cassette. The nlet end 25G of the fluid outflow passageway 254 co~unicates with the outlet er.d 218 of the optional air-in-l~ne detectol passagew~y. The outlet end 258 of the fluid outflow passageway 254 communicates with the inlet end 220 of the outlet check valv~ inlet passa~eway 222 (Fig. 7). If the groove 216-218 is omitted, the groove ends 252 an~ 256 commLnicate directly, an~ uid flows dire_tly from the outlet 252 to the inlet 2~6 of the fluid outflow passageway 25~. -Fig. 10 is a partial cross-sectional view of the cassette assembly showing the pump diaphragm and inactive ch~c~ valves d~ring priming, and Fig. 11 i5 a view of the cassette assembly showlng the check valve~
after activation. Initially, the knob 78 is rotate~ to press the element 144 against che diaphra~m disk 76 to activate the chec~ valve, the position shown in Fig.
11. This closes the outlet valve, and in this position, -2a-the ~ump cassette can ~erform the functions of a traditional roller clamp, preventing fluid flGw thrGugh the system until desired. After connecting the inlet tubing 14 to the inlet tubing nipple 80 and to the liquid source, and after connecting the outlPt tubing 20 to the outlet tu~in~ nipple, the outlet check valve is deactivated (opened) ~y rotati.ng the. knob 78 to the pOSitiOIl sho~n in Eig. lG. ~ic~id then flows ~ro~ the source 2 through the inlet tubing 14, inlet ~assageway 82 and into the inlet check va.lve inlet 86. ~he inlet check valve washer or diaphragm 74 is space~ from the sea~ 90 of the inlet chec~ valve, and fluid passes ket~een the ridge 90 and the opposing surface of the inlet check valve diaphragm and through the central opening 112 of the check valve diaphraym. The fluid then passes across the face of the inlet check valve actuator and to the outlet passageway 204. The fluid is tllen directed to the diaphragm pump chamher, displacing air in the pump chamber until it is filled with fluid.
The fluid then continues to pass th~ough the opt.onal air-in-line detector loop 21~ ig. 7) and passageway 254 until it reaches the outlet check valve chamber, erAterin~ throu~Jh passag~way 22~. Since th~ outlet chec~
valve diaphragm opening 114 is urobstructed, ~luid i.s free to pass througll the opening 114, into the outlet check valve chamber 10~, throuc~h the out:let pa~sageway 106 and t:o the outlet tubing 20. Air is thus displaced from t~e pumping unit, and i-~ is ~/rimed for operation.
The knGb 7~ ic. than turr.ed tc activat~ !depress) the outlet check-valve, moving the certral dis}c 144 i.nto contact with the outlet check valve diaphra~m and .
blocking the central opening 114 in the outlet check valve diaphragm 76. The thinned continuous we~ portion 15~
1~6 stretches without breaking, permitting movement of the cencral disk 1~4 without detachment from the back plate or loss of integrity of outlet check valve. The final position is ch~wn in Fig. 11. Tne primed, set pump cassette of this invention is then mounted on the motor drive housin~ in the position shown in ~ig. 2, the self-threading motor drive member 44 securely mounted in the drive rece~tor 14~.
The pumping cassette connected to the motor drive is shown in Fig. 11, with the exception that the motor drive housing is not shown. In being mounted in the motor drive housin-~, the inlet check valve me~ber 122 is depressed by a protruding surface of the housing. The central disk 122 is pressed toward the inlet check valve diaphraym 74, the circular ridge 200 pressing the diaphragm 74 inward and against the raised circular ridge of the valve seat gO. Thus the inlet check valve is activated by the operation o pressiny the pumping cassette against a raised portion of the motor drive 20 housing.
It will be readily apparen~ to a person skilled in the art that t'ie outlet check valve can also be constructed to ~le a~tivated by a portion of the motor drive housir.g rather than a separ~te knob ~8, o-r that 25 the inlet check valve can be constru~ted to be separately activated by a control ~nob rather than the motor housing surface, and both of these alterna~ive embodiments are included within this inventicn.
However, the embodiment shown in ~iy. 10 and ~1 is the 30 preferred embodiment. After pumping is terminated, the pumping cassette can be disconnected from the motor drive and removed from the motor drive housing. The inlet check valve wi]l be inactivated to the open position upon return of the inlet check valve elements to the initial prin,ing position shown in Fig. 10. The knob 78 can be rotated to a positicn which establishes the desired gravity flow rate, assuming the fluid source is positioned at a higher elevation such as shown in Fig. 1.
Fig. 12 is a partial cross-sectional view of the installed cassette assembly of Fig. 10 during the output phase of the pumping cycle, and Fig. 13 shows the installed cassette assembly during the filling phase of the pumping cycle. D~ring the output phase, the motor drive element 44 advances toward the pumping cassette, moving the face 212 of the central diaphragm segment 128 toward the opposing face of the pump chamber cavity, thus reducing the volur.le of the pumping chamber. This movement is permitted by the flexure (with some stretching) of the hinge segments 134, 13~, 138 and 140 and the corresponding movement of the rigi~ plate segments 130 and }32. The combination of the rigid ~late segments and small area of the hi~ges provides an~
prevents any signlficant distortion of the pumping chan~er vol~me due to flexure of the pumping surfaces in the manner of resilient pump diaphrasms. The pump of this invention thuc combines the uniclue features o~ a diaphra~m pump with the preci~ion of a piston pump.
With the pump configuration of this invention, an output volume which is a function of the pumping displacement is achieved, permitting the control precision o~ a piston pump with the simple construction and energy 30 efficiency of a diaphra~n pump.
The fluid expressed from the pumping chamber is expelled through the outlet passageway 252 and eventually to the outlet chec]c valve. The fluid i.?~9.~i53 -23~
pressure between the element 144 and the outlet check valve diaphra~n 76 displaces th~ diaphragm surface from the surface of the element 144, exposing the diaphra~m passageway 114. Liquid passes through opening 114 and the outlet passageway 106 ~o tubing 20. Reverse flow of liquid to the source is prevented by the construction of the inlet check valve. The volume 121 defin~d by the surface of the actuator 122, the ridge 2C0 and the inlet check valve diaphragm 74 is in direct communication with the pumping chan~er, and the increased pressure of the output phase of the pump pressles the diaphragm 74 securely against the seat 90, preventing fluid escape to the inlet passageway.
The reverse flGw of the fill~ng ph~se of the pump is shown in Fig. 13. Reverse motion of the pump element 44 pulls the central rigid diaphragm segment 128 away from the opposing surface of the front plate, increasin~ the volume of the pumping chambGr. ~hP rigid, hin~ed plates 130 and 132 follow, the plate structure berldin~ about the hinges 134, 136, 138 and 14G. The rigid plate construction again achieves a volume change which is a direct function of the displacement of the actuator 44, achieving a precise filling volume. The volume is not affected significantly by the dif~erence in pump chamber pressure and atmospher~c pressure.
The pressure in the pumping ~hamber and chamber 121 during the filling phase falls below the relative pressure in the inlet conduit 8~ and inlet check valve inlet 86. The inlet fluid pressure displaces the face of the inlet check valve diaphragm 74 away from the valve seat 90, permitting liquid flow through the inlet check valve to the passageway 204 and to the pumping chamber. The pressure in the outlet flow passageway 105 and outlet check valve chambe- 104 also exceeùs the pressure in the pumping cham~er during the filling ~hase, pressing the outlet check valve diaphragm 76 firmly against the surface of the outlet check valve element 144. Reverse flow of l.iquid from the outlet conduit 20 during the filling phase is thus prevented.
The outlet check valve assembly ~rovides an additionzl safety feature. If the c.assette 16 becomes dislodged from the housing 18, the outlet chec~. valve actuator 144 remains in the for~ard position, pressing agair.st the disk 76 and preventing any further fluid flow to the patient.
Fig. 1~ is a partial, fr~gmented vie~J of the disposakle cassette of this invention mounted on the motor housing. The mounting tabs or ears 5~ and 56 the front plate (Fig. 9) are engaged with mounting groove 250 (shown as dotted lines) defined by the upper mountiny flanges 60 ~nd 61 and mounting groova.25~ by cloc~;wise rotation of th6 cassette 16. The rotation is termi~lated b-~ the abutl,lent of the ~abs with the ends of the grcove, 254 and 256. The drive elem.en~ 4~ is fixed against rotation about its axis. Rotation o~ the cassette to engage the tabs 54 and 56 with the ~ounting flanges 60 and 61 threa~s the recept~r 46 ont.~ the barbs 25 or self-threading screw threads 45 on the surface of the drive element 44.
Claims
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. A diaphragm pump cassette for use with a pumping mechanism comprising a pumping chamber, and a check valve means communicating with the pumping chamber, said check valve means including a first check valve and a second check valve, each check valve including a valve seat, a flexible valve diaphragm, and moveable valve seating means for locating said diaphragm on said valve seat, said valve diaphragms being unseated with respect to said valve seat prior to mounting said pump cassette on said pumping mechanism whereby fluid may flow freely through said check valve means, further including a cassette back plate, wherein said valve seating means is a check valve plate attached to the back plate by a flexible hinge means.
2. The diaphragm pump cassette of claim 1 wherein said valve seating means of said first check valve includes means, independent of said pumping mechanism for manually opening and closing said first check valve.
3. The diaphragm pump cassette of claim 1 wherein said cassette is operable with said pumping mechanism only when said diaphragm of said first check valve is seated on its valve seat, said first and second check valves being capable of opening and closing in response to pressure changes developed in said pumping chamber when said diaphragms are seated on said valve seats.
4. The diaphragm pump cassette of claim 1 wherein the closing of said first check valve by said manually opening and closing means causes said valve seating means of said first check valve to seat the diaphragm of the first check valve on its valve seat; and wherein said valve seating means of said second check valve automatically seats the diaphragm of said second check valve on its valve seat when said cassette is mounted on said pumping mechanism.
5. The diaphragm pump cassette of claim 1 wherein said means for manually opening and closing said first check valve includes an adjustment means threadingly engaging the back plate and having a surface opposing the check valve plate for pressing the check valve plate toward the diaphragm.
6. The diaphragm pump cassette of claim 1 wherein the second check valve is an inlet check valve comprising an inlet check valve plate, a valve seat opposing the check valve plate, and a flexible diaphragm disk with a central flow passageway between the inlet check valve plate and the valve seat.
7. The diaphragm pump cassette of claim 6 wherein the flexible inlet diaphragm disk has an inlet side facing the valve seat and communicating with a fluid inlet, and an outlet side facing the inlet check valve plate and communicating with the pumping chamber, the inlet check valve plate being a check valve activation member which by pressing the flexible inlet diaphragm disk against the valve seat closes the inlet check valve.
8. The diaphragm pump cassette of claim 1 wherein said first check valve is an outlet check valve comprising an outlet check valve plate including a valve seat, an outlet check valve chamber opposing the valve seat, and a flexible outlet diaphragm disk with a central flow passageway between the outlet check valve plate and the outlet check valve chamber.
9. The diaphragm pump cassette of claim 8 wherein the flexible outlet diaphragm disk has an inlet face facing the valve seat and communicating with the pumping chamber and an outlet face facing the outlet check valve chamber and communicating with a fluid outlet, the outlet check valve plate being a check valve activation member which by pressing the valve seat against the flexible outlet diaphragm disk, closes the outlet check valve.
1. A diaphragm pump cassette for use with a pumping mechanism comprising a pumping chamber, and a check valve means communicating with the pumping chamber, said check valve means including a first check valve and a second check valve, each check valve including a valve seat, a flexible valve diaphragm, and moveable valve seating means for locating said diaphragm on said valve seat, said valve diaphragms being unseated with respect to said valve seat prior to mounting said pump cassette on said pumping mechanism whereby fluid may flow freely through said check valve means, further including a cassette back plate, wherein said valve seating means is a check valve plate attached to the back plate by a flexible hinge means.
2. The diaphragm pump cassette of claim 1 wherein said valve seating means of said first check valve includes means, independent of said pumping mechanism for manually opening and closing said first check valve.
3. The diaphragm pump cassette of claim 1 wherein said cassette is operable with said pumping mechanism only when said diaphragm of said first check valve is seated on its valve seat, said first and second check valves being capable of opening and closing in response to pressure changes developed in said pumping chamber when said diaphragms are seated on said valve seats.
4. The diaphragm pump cassette of claim 1 wherein the closing of said first check valve by said manually opening and closing means causes said valve seating means of said first check valve to seat the diaphragm of the first check valve on its valve seat; and wherein said valve seating means of said second check valve automatically seats the diaphragm of said second check valve on its valve seat when said cassette is mounted on said pumping mechanism.
5. The diaphragm pump cassette of claim 1 wherein said means for manually opening and closing said first check valve includes an adjustment means threadingly engaging the back plate and having a surface opposing the check valve plate for pressing the check valve plate toward the diaphragm.
6. The diaphragm pump cassette of claim 1 wherein the second check valve is an inlet check valve comprising an inlet check valve plate, a valve seat opposing the check valve plate, and a flexible diaphragm disk with a central flow passageway between the inlet check valve plate and the valve seat.
7. The diaphragm pump cassette of claim 6 wherein the flexible inlet diaphragm disk has an inlet side facing the valve seat and communicating with a fluid inlet, and an outlet side facing the inlet check valve plate and communicating with the pumping chamber, the inlet check valve plate being a check valve activation member which by pressing the flexible inlet diaphragm disk against the valve seat closes the inlet check valve.
8. The diaphragm pump cassette of claim 1 wherein said first check valve is an outlet check valve comprising an outlet check valve plate including a valve seat, an outlet check valve chamber opposing the valve seat, and a flexible outlet diaphragm disk with a central flow passageway between the outlet check valve plate and the outlet check valve chamber.
9. The diaphragm pump cassette of claim 8 wherein the flexible outlet diaphragm disk has an inlet face facing the valve seat and communicating with the pumping chamber and an outlet face facing the outlet check valve chamber and communicating with a fluid outlet, the outlet check valve plate being a check valve activation member which by pressing the valve seat against the flexible outlet diaphragm disk, closes the outlet check valve.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/799,235 US4759264A (en) | 1985-11-18 | 1985-11-18 | Parenteral solution diaphragm pump |
| US799,235 | 1985-11-18 | ||
| US06/902,616 US4768547A (en) | 1985-11-18 | 1986-09-02 | Parenteral solution pump assembly |
| US902,616 | 1992-06-23 |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000523150A Division CA1272921A (en) | 1985-11-18 | 1986-11-17 | Parenteral solution diaphragm pump |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1293153C true CA1293153C (en) | 1991-12-17 |
Family
ID=27122090
Family Applications (3)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000523150A Expired - Lifetime CA1272921A (en) | 1985-11-18 | 1986-11-17 | Parenteral solution diaphragm pump |
| CA000613073A Expired - Lifetime CA1293153C (en) | 1985-11-18 | 1989-09-25 | Parenteral solution diaphragm pump |
| CA000615720A Expired - Lifetime CA1292655C (en) | 1985-11-18 | 1990-05-04 | Check valve for a parenteral solution delivery system |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000523150A Expired - Lifetime CA1272921A (en) | 1985-11-18 | 1986-11-17 | Parenteral solution diaphragm pump |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000615720A Expired - Lifetime CA1292655C (en) | 1985-11-18 | 1990-05-04 | Check valve for a parenteral solution delivery system |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US4768547A (en) |
| EP (2) | EP0333305B1 (en) |
| KR (1) | KR870004711A (en) |
| AT (2) | ATE91907T1 (en) |
| AU (2) | AU601380B2 (en) |
| CA (3) | CA1272921A (en) |
| DE (2) | DE3681885D1 (en) |
| ES (2) | ES2047104T3 (en) |
| GR (1) | GR3002877T3 (en) |
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| AU643030B2 (en) * | 1990-06-21 | 1993-11-04 | Comweld Group Pty Ltd | Minimum pressure retaining non-return valve |
| DE4039814A1 (en) * | 1990-12-13 | 1992-06-17 | Logica Medizintechnik Gmbh | CHECK VALVE, ESPECIALLY FOR MEDICAL INFUSION DEVICES |
| US5095932A (en) * | 1990-12-21 | 1992-03-17 | Millipore Corporation | Check valve for fluid delivery system |
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| US988472A (en) * | 1910-11-18 | 1911-04-04 | John H Kinealy | Diaphragm. |
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-
1986
- 1986-09-02 US US06/902,616 patent/US4768547A/en not_active Expired - Fee Related
- 1986-11-17 AT AT89201102T patent/ATE91907T1/en not_active IP Right Cessation
- 1986-11-17 EP EP19890201102 patent/EP0333305B1/en not_active Expired - Lifetime
- 1986-11-17 AU AU65369/86A patent/AU601380B2/en not_active Ceased
- 1986-11-17 DE DE8686308935T patent/DE3681885D1/en not_active Expired - Lifetime
- 1986-11-17 AT AT86308935T patent/ATE68242T1/en not_active IP Right Cessation
- 1986-11-17 CA CA000523150A patent/CA1272921A/en not_active Expired - Lifetime
- 1986-11-17 EP EP19860308935 patent/EP0223580B1/en not_active Expired - Lifetime
- 1986-11-17 DE DE19863688795 patent/DE3688795T2/en not_active Expired - Fee Related
- 1986-11-17 ES ES89201102T patent/ES2047104T3/en not_active Expired - Lifetime
- 1986-11-17 ES ES86308935T patent/ES2026134T3/en not_active Expired - Lifetime
- 1986-11-18 KR KR860009730A patent/KR870004711A/en not_active Application Discontinuation
-
1989
- 1989-09-25 CA CA000613073A patent/CA1293153C/en not_active Expired - Lifetime
-
1990
- 1990-03-15 AU AU51381/90A patent/AU640126B2/en not_active Ceased
- 1990-05-04 CA CA000615720A patent/CA1292655C/en not_active Expired - Lifetime
-
1991
- 1991-10-10 GR GR91401513T patent/GR3002877T3/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| EP0333305B1 (en) | 1993-07-28 |
| ES2047104T3 (en) | 1994-02-16 |
| GR3002877T3 (en) | 1993-01-25 |
| DE3681885D1 (en) | 1991-11-14 |
| CA1272921A (en) | 1990-08-21 |
| AU5138190A (en) | 1990-07-05 |
| EP0223580A3 (en) | 1988-01-13 |
| CA1292655C (en) | 1991-12-03 |
| EP0333305A2 (en) | 1989-09-20 |
| ATE68242T1 (en) | 1991-10-15 |
| AU601380B2 (en) | 1990-09-13 |
| EP0223580A2 (en) | 1987-05-27 |
| AU6536986A (en) | 1987-05-21 |
| DE3688795D1 (en) | 1993-09-02 |
| US4768547A (en) | 1988-09-06 |
| DE3688795T2 (en) | 1993-11-04 |
| ATE91907T1 (en) | 1993-08-15 |
| EP0333305A3 (en) | 1989-11-02 |
| AU640126B2 (en) | 1993-08-19 |
| ES2026134T3 (en) | 1992-04-16 |
| KR870004711A (en) | 1987-06-01 |
| EP0223580B1 (en) | 1991-10-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |