US3741732A - Fractional-fill pipette assembly - Google Patents

Fractional-fill pipette assembly Download PDF

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Publication number
US3741732A
US3741732A US00254764A US25476472A US3741732A US 3741732 A US3741732 A US 3741732A US 00254764 A US00254764 A US 00254764A US 25476472 A US25476472 A US 25476472A US 3741732 A US3741732 A US 3741732A
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Prior art keywords
fractional
capillary
fill
hydrophobic
liquid
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US00254764A
Inventor
T Stanfield
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BECON DICKINSON AND CO
BECON DICKINSON AND CO US
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BECON DICKINSON AND CO
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Priority to DE1966B0088003 priority Critical patent/DE1598123A1/en
Priority to DE1966B0088004 priority patent/DE1598124A1/en
Application filed by BECON DICKINSON AND CO filed Critical BECON DICKINSON AND CO
Priority to US00254764A priority patent/US3741732A/en
Priority to FR7319242A priority patent/FR2185051B3/fr
Priority to DE2324681A priority patent/DE2324681C2/en
Priority to JP48054162A priority patent/JPS5211600B2/ja
Application granted granted Critical
Publication of US3741732A publication Critical patent/US3741732A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L9/00—Supporting devices; Holding devices
    • B01L9/54—Supports specially adapted for pipettes and burettes
    • B01L9/543—Supports specially adapted for pipettes and burettes for disposable pipette tips, e.g. racks or cassettes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/15—Devices for taking samples of blood
    • A61B5/150007—Details
    • A61B5/150015—Source of blood
    • A61B5/150022—Source of blood for capillary blood or interstitial fluid
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/15—Devices for taking samples of blood
    • A61B5/150007—Details
    • A61B5/150053—Details for enhanced collection of blood or interstitial fluid at the sample site, e.g. by applying compression, heat, vibration, ultrasound, suction or vacuum to tissue; for reduction of pain or discomfort; Skin piercing elements, e.g. blades, needles, lancets or canulas, with adjustable piercing speed
    • A61B5/150061—Means for enhancing collection
    • A61B5/150099—Means for enhancing collection by negative pressure, other than vacuum extraction into a syringe by pulling on the piston rod or into pre-evacuated tubes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
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    • A61B5/15—Devices for taking samples of blood
    • A61B5/150007—Details
    • A61B5/150206—Construction or design features not otherwise provided for; manufacturing or production; packages; sterilisation of piercing element, piercing device or sampling device
    • A61B5/150213—Venting means
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
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    • A61B5/15—Devices for taking samples of blood
    • A61B5/150007—Details
    • A61B5/150206—Construction or design features not otherwise provided for; manufacturing or production; packages; sterilisation of piercing element, piercing device or sampling device
    • A61B5/150236—Pistons, i.e. cylindrical bodies that sit inside the syringe barrel, typically with an air tight seal, and slide in the barrel to create a vacuum or to expel blood
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
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    • A61B5/150007—Details
    • A61B5/150206—Construction or design features not otherwise provided for; manufacturing or production; packages; sterilisation of piercing element, piercing device or sampling device
    • A61B5/150244—Rods for actuating or driving the piston, i.e. the cylindrical body that sits inside the syringe barrel, typically with an air tight seal, and slides in the barrel to create a vacuum or to expel blood
    • A—HUMAN NECESSITIES
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    • A61B5/150007—Details
    • A61B5/150206—Construction or design features not otherwise provided for; manufacturing or production; packages; sterilisation of piercing element, piercing device or sampling device
    • A61B5/150259—Improved gripping, e.g. with high friction pattern or projections on the housing surface or an ergonometric shape
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    • 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
    • A—HUMAN NECESSITIES
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    • 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
    • A61M5/178—Syringes
    • A61M5/31—Details
    • A61M5/315—Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
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    • 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
    • A61M5/178—Syringes
    • A61M5/31—Details
    • A61M5/32—Needles; Details of needles pertaining to their connection with syringe or hub; Accessories for bringing the needle into, or holding the needle on, the body; Devices for protection of needles
    • A61M5/34—Constructions for connecting the needle, e.g. to syringe nozzle or needle hub
    • A61M5/344—Constructions for connecting the needle, e.g. to syringe nozzle or needle hub using additional parts, e.g. clamping rings or collets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01L3/02—Burettes; Pipettes
    • B01L3/021—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B01L3/02—Burettes; Pipettes
    • B01L3/021—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids
    • B01L3/0213—Accessories for glass pipettes; Gun-type pipettes, e.g. safety devices, pumps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/02—Burettes; Pipettes
    • B01L3/021—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids
    • B01L3/0217—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids of the plunger pump type
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/02—Burettes; Pipettes
    • B01L3/021—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids
    • B01L3/0217—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids of the plunger pump type
    • B01L3/0224—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids of the plunger pump type having mechanical means to set stroke length, e.g. movable stops
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/02—Burettes; Pipettes
    • B01L3/021—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids
    • B01L3/0217—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids of the plunger pump type
    • B01L3/0231—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids of the plunger pump type having several coaxial pistons
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/02—Burettes; Pipettes
    • B01L3/0241—Drop counters; Drop formers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/02—Burettes; Pipettes
    • B01L3/0275—Interchangeable or disposable dispensing tips
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/02—Burettes; Pipettes
    • B01L3/0275—Interchangeable or disposable dispensing tips
    • B01L3/0279—Interchangeable or disposable dispensing tips co-operating with positive ejection means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/02—Burettes; Pipettes
    • B01L3/0282—Burettes; Pipettes mounted within a receptacle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L9/00—Supporting devices; Holding devices
    • B01L9/06—Test-tube stands; Test-tube holders
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/69—Sulfur trioxide; Sulfuric acid
    • C01B17/90—Separation; Purification
    • C01B17/907—Removal of arsenic
    • 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
    • A61M5/178—Syringes
    • A61M5/31—Details
    • A61M5/315—Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
    • A61M5/31525—Dosing
    • A61M5/31531—Microsyringes, e.g. having piston bore diameter close or equal to needle shaft diameter
    • 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
    • A61M5/178—Syringes
    • A61M5/31—Details
    • A61M5/32—Needles; Details of needles pertaining to their connection with syringe or hub; Accessories for bringing the needle into, or holding the needle on, the body; Devices for protection of needles
    • A61M5/34—Constructions for connecting the needle, e.g. to syringe nozzle or needle hub
    • A61M5/346—Constructions for connecting the needle, e.g. to syringe nozzle or needle hub friction fit
    • 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
    • A61M5/178—Syringes
    • A61M5/31—Details
    • A61M5/32—Needles; Details of needles pertaining to their connection with syringe or hub; Accessories for bringing the needle into, or holding the needle on, the body; Devices for protection of needles
    • A61M5/34—Constructions for connecting the needle, e.g. to syringe nozzle or needle hub
    • A61M5/347—Constructions for connecting the needle, e.g. to syringe nozzle or needle hub rotatable, e.g. bayonet or screw
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01L2200/00—Solutions for specific problems relating to chemical or physical laboratory apparatus
    • B01L2200/04—Exchange or ejection of cartridges, containers or reservoirs
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B01L2300/00—Additional constructional details
    • B01L2300/08—Geometry, shape and general structure
    • B01L2300/0832—Geometry, shape and general structure cylindrical, tube shaped
    • B01L2300/0838—Capillaries

Definitions

  • ABSTRACT A fractional-fill pipette assembly adapted to fill to a predetermined mark to obtain a desired known volume of liquid such as blood, plasma, test reagents or the like is disclosed.
  • a means formed of a hydrophobic material is positioned within the tube bore, a predetermined distance from one end thereof so as to divide the capillary tube into two segments, one of the segments having a 7 Claims, 5 Drawing Figures 1 FRACTIONAL-FILL PIPE'ITE ASSEMBLY BACKGROUND OF THE INVENTION Pipette assemblies for delivering precise known volumes of fluid such as blood are in use in laboratories and hospitals. Where blood samples are taken for analytical purposes such as blood cell counting, a Trenner pipette is employed.
  • micropipettes which are made in the form of a syringe which will fill to a mark by retracting the piston from the barrel portion of the syringe.
  • the barrel is in the form of a capillary so that as the piston is retracted, a volume of liquid will fill the displaced portion of the barrel.
  • micropipette assemblies are employed in which a capillary of known length and volume is filled throughout its entire length by capillary action such as is described in US Pat. No. 3,045,494.
  • a capillary of known length and volume is filled throughout its entire length by capillary action such as is described in US Pat. No. 3,045,494.
  • a fractional fill pipette assembly having a means formed of a hydrophobic material which is disposed within the tube bore a predetermined distance from one end thereof in which the distance between the end of the capillary and the hydrophobic means defines a zone of known volumetric capacity.
  • My invention generally contemplates providing a partial fill pipette assembly which includes a tube with a bore extending therethrough and a hydrophobic means positioned in the tube bore a predetermined distance between the ends thereof to define azone from one end of the tube to the hydrophobic means having a precise known volumetric capacity so that when a column of fluid fills the tube bore to the hydrophobic means a precise volume of liquid can bequantitated.
  • FIG. 1 A fractional-fill pipette assembly is illustrated in FIG. 1 and is best illustrated in FIG. 3 in which the fractional-fill pipette assembly 10 is shown fully assembled in sectional view.
  • the pipette or capillary assembly 10 includes a hydrophobic means 12 positioned in the capillary bore 13 between ends 14 and 16 of capillary tube 11.
  • Holder 20 is mounted on the capillary tube in frictional engagement therewith and between ends 14 and 16 and is employed to facilitate holding the pipette during use such as for filling and subsequently dispensing the predetermined volume of fluid contained in zone or segment 17 defined between end14 and hydrophobic means 12 of pipette l1.
  • Hydrophobic means 12 is shown in FIG. 2a and is illustrated mounted in position in FIG. 3 in detail. Hy-.
  • drophobic means 12 is preferably made of a hydrophobic material such as polyethylene or other type polyolefins or any other plastic material which has hydrophov bic characteristics or may even be a wettable material which is coated with a hydrophobic coating such as paraffin wax, beeswax or various plastic made into dilute lacquers which will render the surfaces of the by
  • the outer diameter of hydrophobic means 12 is slightly larger than the internal bore diameter of capillary tube 11 such that when hydrophobic means 12 is inserted into capillary bore 13, hydrophobic means 12 will frictionally engage the surfacesof bore 13 and when positioned will be a fixed predetermined: distance from end 14 and will not move unless a positive force is applied thereto.
  • the mechanism for properly positioning hydrophobic means 12 within capillary bore 13 is illustrated in FIG. 4 in exploded orientation which illustrates the sequence of steps for assembling the fractional-fill micropipetteof FIG. 1.
  • Holder 20 is preferably formed of a plastic material such as polyethylene and comprises a body portion 21 having a bore or passage 22 formed therethrough and is of a diameter such that it will slidably receive capillary 11 and when'mounted in position, as seen in FIG. 3, will be held in fixed position by frictional engagement with exterior surfaces 15 of capillary 11 and the interior surfaces of bore 22 of holder 20.
  • Holder 20, as shown in FIGS. 1 and 3, is positioned on capillary 11 a greater distance from end 14 than hydrophobic means 12 for facilitate the operator's vision of the entire zone which contains the accurately filled fluid in capillary 11 between end 14 and hydrophobic means 12.
  • holder 20 may be positioned between end 14 of capillary lland hydrophobic means 12 which will and illustrated in copending application of Waldemar Ayres filed even date herewith entitled Fractional-Fill Capillary Pipette and Method.
  • Holder as indicated is preferably formed of a suitable plastic material and is molded having tubular body portion 21. Integrally formed therewith and extending from body portion or sleeve 21 is a finger engaging member or tab 24. Tab 24 presents a suitable surface for a label for receiving indicia such as is used to identify the sample to be tested or to specify the fractional fill capacity.
  • Sleeve 21 at its forward end terminates in a reduced flange 26 which is adapted to couple to a reservoir (not shown) having a predetermined measured volume of diluent such as is disclosed in the aforesaid copending patent application.
  • FIG. 2b another form of hydrophobic means 12 is illustrated and is generally referred to as 12'.
  • Hydrophobic means 12' is preferably made of a suitable plastic material which is made non-wettable.
  • Hydrophobic means 12' is molded in the shape of a frustro conical cone having a passage 37' extending between the forward end 35' and rear end 30. Forward end 35 is of reduced diameter and rear end 30' has a diameter slightly greater than the bore diameter of capillary 11 so that hydrophobic means 12' when positioned in bore 13 of capillary 11, an interference fit is formed to prevent accidental displacement thereof.
  • Hydrophobic means 12 and 13' is mounted in capillary 11 by the assembly device 40 illustrated in FIG. 4.
  • the assembly device 40 comprises a rod 44 mounted on handle 42.
  • Rod 44 has a diameter less than the diameter of bore 13 of capillary 11 to facilitate insertion of rod 44 therein.
  • Assembly device 40 is made of a rigid material which may be plastic with high impact strength or may be formed of metal with rod 44 being mounted to handle 42 in any convenient manner such as by threading, or swaging.
  • the forward end 46 of rod 44 terminates in a reduced flange 48 having a diameter substantially equal to but less than the passage formed in hydrophobic means 12 or'l2'.
  • Slidably mounted on rod 44 is an adjustable depth insertion guide 50 for inserting hydrophobic means 12 M12 to the exact distance from end 14 in capillary bore 13.
  • Insertion guide 50 comprises an annular ring 52 having a passage therethrough with a diameter slightly greater than the diameter of rod 44. Ring 52 is held at the desired position by any convenient means such as a lock adjusting set screw 54 which is threadedly engaged in a threaded opening in annular ring 52. When set screw 54 is threaded through annular ring 52 the forward end biases against rod 44 to hold insertion guide 50 in a fixed predetermined position. Thus, the insertion depth as depicted in FIG. 4 is the distance between end 46 and rod 44 and insertion guide 50. The flange portion 48 is inserted into passage 30 of hydrophobic means 12 and then the hydrophobic means is inserted to the proper depth. Holder 20, as noted, is slidably mounted on capillary 11 by simply passing either end 14 or 16 of capillary 11 into passage 22 of holder 20, at end 56 or 58.
  • a fractional-fill pipette assembly for the quantitation of a liquid comprising:
  • a capillary tube capable of being filled with fluid by capillarity when the one end of the tube is immersed in the fluid to be quantitated
  • a hydrophobic means associated with the tube bore and positioned a predetermined distance from said one end of said tube to define a zone having a predetermined known volume
  • said hydrophobic means having a passage formed therethrough so that said other end of said capillary is open to the atmosphere whereby when said fluid contacts said hydrophobic means the fluid ceases filling to provide a precise known volume of fluid in said zone.
  • hydrophobic means is a tubular member made of molded plastic, said member having a zone of increased diameter slightly greater than the bore diameter of the capillary so as to provide an interference fit in the capillary after being positioned a predetermined distance from said one end.
  • said holder comprises an integrally molded plastic body including a sleeve having a passage therethrough, said passage having a zone where the diameter is substantially equal to the outer diameter of the capillary tube so that when slidably mounted in position an interference fit is formed.
  • hydrophobic means is a tubular member made of a molded plastic material having a central zone, the outside diameter of which is slightly greater than the bore diameter of the capillary tube and extending from said zone is at least one frustro conical cone integrally formed therewith.

Abstract

A fractional-fill pipette assembly adapted to fill to a predetermined mark to obtain a desired known volume of liquid such as blood, plasma, test reagents or the like is disclosed. A means formed of a hydrophobic material is positioned within the tube bore, a predetermined distance from one end thereof so as to divide the capillary tube into two segments, one of the segments having a precise known volumetric capacity for collecting a desired known volume of liquid so that when the liquid fills the segment containing the precise known volume the liquid contacts the hydrophobic means defining the interface between the segments, the hydrophobic means breaks or resists the forces acting on the liquid filling the bore and prevents liquid from filling the pipette beyond the hydrophobic means by maintaining the surface tension of the liquid at the interface between the fluid and the hydrophobic means.

Description

United States Patent [191 [4 June 26, 1973 Stanfield I FRACTIONAL-FILL PIPETTE ASSEMBLY [75] inventor: Trevelyan A. Stanfield, Nutley, NJ.
[73] Assignee: Becon, Dickinson and Company, East Rutherford, NJ.
[22] Filed: May 18, 1972 [21] Appl. No.: 254,764
[52] US. Cl. 73/42S.4 P
[51] Int. Cl B011 3/02 [58] Field of Search 73/4254 P, 425.6; 141/18, 31
[56] References Cited V p v UNITED STATES PATENTS 1,678,540 '7/1 928 Trenner 73/4254 P 2,685,800 8/1954 Natelson.. 73/4254 P 2,974,528 3/1961 Sanz 73/4254 P 3,285,296 11/1966 lshimaru 73/4256 3,500,689 3/1970 Band 73/4254 P 3,045,494 7/1962 'Gerarde 73/4256 Primary Examiner-S. Clement Swisher Attorney- David S. Kane, James J. Sa1erno :lr. e551.
[5 7] ABSTRACT A fractional-fill pipette assembly adapted to fill to a predetermined mark to obtain a desired known volume of liquid such as blood, plasma, test reagents or the like is disclosed. A means formed of a hydrophobic material is positioned within the tube bore, a predetermined distance from one end thereof so as to divide the capillary tube into two segments, one of the segments having a 7 Claims, 5 Drawing Figures 1 FRACTIONAL-FILL PIPE'ITE ASSEMBLY BACKGROUND OF THE INVENTION Pipette assemblies for delivering precise known volumes of fluid such as blood are in use in laboratories and hospitals. Where blood samples are taken for analytical purposes such as blood cell counting, a Trenner pipette is employed. Also, there are micropipettes which are made in the form of a syringe which will fill to a mark by retracting the piston from the barrel portion of the syringe. The barrel is in the form of a capillary so that as the piston is retracted, a volume of liquid will fill the displaced portion of the barrel.
Other micropipette assemblies are employed in which a capillary of known length and volume is filled throughout its entire length by capillary action such as is described in US Pat. No. 3,045,494. However, it is difficult to handle and measure accurately precise, volumes of fluid employing presently available micropipettessince they require dexterity by the technician using themand, in many cases, an error in operation of a micropipette leads to erroneous test results.
SUMMARY or THE INVENTION With theforegoing in mind itis an object of the present invention to provide a fractional fill pipette assembly having a means formed of a hydrophobic material which is disposed within the tube bore a predetermined distance from one end thereof in which the distance between the end of the capillary and the hydrophobic means defines a zone of known volumetric capacity. When the liquid filling the tube bore reaches the hydrophobic means the forces acting on the liquid are equilibrated thereby forming an interface between a wettable zone and a non-wettable zone.
It is a further object of the invention to provide a partial fill capillary assembly. which will-automatically fill to a' predetermined point or mark so thata jprecise known volume of fluid will be measured and the precise volumeoffluid will be available for dilution in a premeasured volume of diluent-to obtain a precise known ratio of solution so that a test can accurately be performed.
My invention generally contemplates providing a partial fill pipette assembly which includes a tube with a bore extending therethrough and a hydrophobic means positioned in the tube bore a predetermined distance between the ends thereof to define azone from one end of the tube to the hydrophobic means having a precise known volumetric capacity so that when a column of fluid fills the tube bore to the hydrophobic means a precise volume of liquid can bequantitated.
BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENTS A fractional-fill pipette assembly is illustrated in FIG. 1 and is best illustrated in FIG. 3 in which the fractional-fill pipette assembly 10 is shown fully assembled in sectional view. The pipette or capillary assembly 10 includes a hydrophobic means 12 positioned in the capillary bore 13 between ends 14 and 16 of capillary tube 11. Holder 20 is mounted on the capillary tube in frictional engagement therewith and between ends 14 and 16 and is employed to facilitate holding the pipette during use such as for filling and subsequently dispensing the predetermined volume of fluid contained in zone or segment 17 defined between end14 and hydrophobic means 12 of pipette l1.
Hydrophobic means 12 is shown in FIG. 2a and is illustrated mounted in position in FIG. 3 in detail. Hy-.
drophobic means 12 is preferably made of a hydrophobic material such as polyethylene or other type polyolefins or any other plastic material which has hydrophov bic characteristics or may even be a wettable material which is coated with a hydrophobic coating such as paraffin wax, beeswax or various plastic made into dilute lacquers which will render the surfaces of the by As noted above, the outer diameter of hydrophobic means 12 is slightly larger than the internal bore diameter of capillary tube 11 such that when hydrophobic means 12 is inserted into capillary bore 13, hydrophobic means 12 will frictionally engage the surfacesof bore 13 and when positioned will be a fixed predetermined: distance from end 14 and will not move unless a positive force is applied thereto. The mechanism for properly positioning hydrophobic means 12 within capillary bore 13 is illustrated in FIG. 4 in exploded orientation which illustrates the sequence of steps for assembling the fractional-fill micropipetteof FIG. 1.
Holder 20 is preferably formed of a plastic material such as polyethylene and comprises a body portion 21 having a bore or passage 22 formed therethrough and is of a diameter such that it will slidably receive capillary 11 and when'mounted in position, as seen in FIG. 3, will be held in fixed position by frictional engagement with exterior surfaces 15 of capillary 11 and the interior surfaces of bore 22 of holder 20. Holder 20, as shown in FIGS. 1 and 3, is positioned on capillary 11 a greater distance from end 14 than hydrophobic means 12 for facilitate the operator's vision of the entire zone which contains the accurately filled fluid in capillary 11 between end 14 and hydrophobic means 12. Also holder 20 may be positioned between end 14 of capillary lland hydrophobic means 12 which will and illustrated in copending application of Waldemar Ayres filed even date herewith entitled Fractional-Fill Capillary Pipette and Method.
Holder as indicated is preferably formed of a suitable plastic material and is molded having tubular body portion 21. Integrally formed therewith and extending from body portion or sleeve 21 is a finger engaging member or tab 24. Tab 24 presents a suitable surface for a label for receiving indicia such as is used to identify the sample to be tested or to specify the fractional fill capacity. Sleeve 21 at its forward end terminates in a reduced flange 26 which is adapted to couple to a reservoir (not shown) having a predetermined measured volume of diluent such as is disclosed in the aforesaid copending patent application.
In FIG. 2b another form of hydrophobic means 12 is illustrated and is generally referred to as 12'. Hydrophobic means 12' is preferably made of a suitable plastic material which is made non-wettable. Hydrophobic means 12' is molded in the shape of a frustro conical cone having a passage 37' extending between the forward end 35' and rear end 30. Forward end 35 is of reduced diameter and rear end 30' has a diameter slightly greater than the bore diameter of capillary 11 so that hydrophobic means 12' when positioned in bore 13 of capillary 11, an interference fit is formed to prevent accidental displacement thereof. Hydrophobic means 12 and 13' is mounted in capillary 11 by the assembly device 40 illustrated in FIG. 4.
The assembly device 40 comprises a rod 44 mounted on handle 42. Rod 44 has a diameter less than the diameter of bore 13 of capillary 11 to facilitate insertion of rod 44 therein. Assembly device 40 is made of a rigid material which may be plastic with high impact strength or may be formed of metal with rod 44 being mounted to handle 42 in any convenient manner such as by threading, or swaging. The forward end 46 of rod 44 terminates in a reduced flange 48 having a diameter substantially equal to but less than the passage formed in hydrophobic means 12 or'l2'. Slidably mounted on rod 44 is an adjustable depth insertion guide 50 for inserting hydrophobic means 12 M12 to the exact distance from end 14 in capillary bore 13. Insertion guide 50 comprises an annular ring 52 having a passage therethrough with a diameter slightly greater than the diameter of rod 44. Ring 52 is held at the desired position by any convenient means such as a lock adjusting set screw 54 which is threadedly engaged in a threaded opening in annular ring 52. When set screw 54 is threaded through annular ring 52 the forward end biases against rod 44 to hold insertion guide 50 in a fixed predetermined position. Thus, the insertion depth as depicted in FIG. 4 is the distance between end 46 and rod 44 and insertion guide 50. The flange portion 48 is inserted into passage 30 of hydrophobic means 12 and then the hydrophobic means is inserted to the proper depth. Holder 20, as noted, is slidably mounted on capillary 11 by simply passing either end 14 or 16 of capillary 11 into passage 22 of holder 20, at end 56 or 58.
Having described the illustrative embodiments of the invention, variations of the invention may be had by changes in design in materials without parting from the spirit and scope of the invention.
I claim:
1. A fractional-fill pipette assembly for the quantitation of a liquid comprising:
a. a capillary tube capable of being filled with fluid by capillarity when the one end of the tube is immersed in the fluid to be quantitated;
b. a hydrophobic means associated with the tube bore and positioned a predetermined distance from said one end of said tube to define a zone having a predetermined known volume;
c. said hydrophobic means having a passage formed therethrough so that said other end of said capillary is open to the atmosphere whereby when said fluid contacts said hydrophobic means the fluid ceases filling to provide a precise known volume of fluid in said zone.
2. The fractional-fill pipette assembly of claim 1 wherein said hydrophobic means is formed of plastic.
3. The fractional-fill pipette assembly of claim 1 wherein said hydrophobic means is coated with a hydrophobic material.
4. The fractional-fill pipette assembly of claim 1 wherein said hydrophobic means is a tubular member made of molded plastic, said member having a zone of increased diameter slightly greater than the bore diameter of the capillary so as to provide an interference fit in the capillary after being positioned a predetermined distance from said one end.
5. The fractional-fill pipette assembly of claim 1 wherein said capillary assembly includes a holder slidably mounted on said capillary and positioned between the ends thereof.
6. The fractional-fill pipette assembly of claim 5 wherein said holder comprises an integrally molded plastic body including a sleeve having a passage therethrough, said passage having a zone where the diameter is substantially equal to the outer diameter of the capillary tube so that when slidably mounted in position an interference fit is formed.
7. The fractional-fill pipette assembly of claim 1 wherein said hydrophobic means is a tubular member made of a molded plastic material having a central zone, the outside diameter of which is slightly greater than the bore diameter of the capillary tube and extending from said zone is at least one frustro conical cone integrally formed therewith.

Claims (6)

  1. 2. The fractional-fill pipette assembly of claim 1 wherein said hydrophobic means is formed of plastic.
  2. 3. The fractional-fill pipette assembly of claim 1 wherein said hydrophobic means is coated with a hydrophobic material.
  3. 4. The fractional-fill pipette assembly of claim 1 wherein said hydrophobic means is a tubular member made of molded plastic, said member having a zone of increased diameter slightly greater than the bore diameter of the capillary so as to provide an interference fit in the capillary after being positioned a predetermined distance from said one end.
  4. 5. The fractional-fill pipette assembly of claim 1 wherein said capillary assembly includes a holder slidably mounted on said capillary and positioned between the ends thereof.
  5. 6. The fractional-fill pipette assembly of claim 5 wherein said holder comprises an integrally molded plastic body including a sleeve having a passage therethrough, said passage having a zone where the diameter is substantially equal to the outer diameter of the capillary tube so that when slidably mounted in position an interference fit is formed.
  6. 7. The fractional-fill pipette assembly of claim 1 wherein said hydrophobic means is a tubular member made of a molded plastic material having a central zone, the outside diameter of which is slightly greater than the bore diameter of the capillary tube and extending from said zone is at least one frustro conical cone integrally formed therewith.
US00254764A 1972-05-18 1972-05-18 Fractional-fill pipette assembly Expired - Lifetime US3741732A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
DE1966B0088003 DE1598123A1 (en) 1972-05-18 1966-07-14 Automatic pipette
DE1966B0088004 DE1598124A1 (en) 1972-05-18 1966-07-14 Pipette tip
US00254764A US3741732A (en) 1972-05-18 1972-05-18 Fractional-fill pipette assembly
FR7319242A FR2185051B3 (en) 1972-05-18 1973-05-16
DE2324681A DE2324681C2 (en) 1972-05-18 1973-05-16 Fractionating pipette
JP48054162A JPS5211600B2 (en) 1972-05-18 1973-05-17

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Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3864979A (en) * 1973-03-30 1975-02-11 Becton Dickinson Co Blood sedimentation tube barrier
US3901085A (en) * 1972-11-30 1975-08-26 Jean Marie Faure Pipette or similar apparatus for measuring determined volumes of liquid
US4091802A (en) * 1976-02-17 1978-05-30 Eastman Kodak Company Vented liquid collection device
US4136036A (en) * 1976-04-07 1979-01-23 Eastman Kodak Company Collection and dispensing device for non-pressurized liquids
US4396024A (en) * 1978-11-09 1983-08-02 Sarstedt W Device for the extraction of capillary blood
US4442722A (en) * 1982-02-23 1984-04-17 Beckman Instruments Inc. Plunger operated pipet
US4461328A (en) * 1982-06-04 1984-07-24 Drummond Scientific Company Pipette device
EP0209705A2 (en) * 1985-07-22 1987-01-28 Drummond Scientific Company A disposable preselected-volume capillary pipet device and method of preparing a liquid sample for testing
FR2604013A1 (en) * 1986-09-12 1988-03-18 Articles Laboratoire Precision PROCESS FOR CHARACTERIZATION OF A LABORATORY INSTRUMENT AND PIPETTE THUS CHARACTERIZED BY COLORING
US5065768A (en) * 1988-09-13 1991-11-19 Safe-Tec Clinical Products, Inc. Self-sealing fluid conduit and collection device
US5456885A (en) * 1993-07-12 1995-10-10 Coleman; Charles M. Fluid collection, separation and dispensing tube
US5460782A (en) * 1994-07-18 1995-10-24 Safe-Tec Clinical Products, Inc. Automatic filling micropipette with dispensing means
US6343717B1 (en) * 2000-11-21 2002-02-05 Jack Yongfeng Zhang Pre-filled disposable pipettes
US20020037239A1 (en) * 2000-09-22 2002-03-28 Fuji Photo Film Co., Ltd. Quantitative suction tip and quantitative suction apparatus
US11084030B2 (en) * 2016-04-12 2021-08-10 Gilson Sas Pipette for sampling an extended range of volumes of liquid
WO2023030577A1 (en) * 2021-08-31 2023-03-09 Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung Holder for an individual capillary tube, and collecting device for a plurality of holders

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US3954014A (en) * 1974-12-16 1976-05-04 Becton, Dickinson And Company Multiple shot pipetter
GB2029723B (en) * 1978-09-12 1982-12-01 Lee T Adjustable volume pipetting device
EP0082263A1 (en) * 1981-12-10 1983-06-29 The Perkin-Elmer Corporation Sample introduction for chemical analysis by spectrometry/liquid chromatography
FR2629203B1 (en) * 1988-03-22 1990-12-07 Serbio DEVICE FOR TRIGGERING A MEASUREMENT CIRCUIT OF A REACTION PARAMETER WHEN DELIVERING A REAGENT DOSE USING A PIPETTE-TANK
GB0011574D0 (en) * 2000-05-12 2000-07-05 Central Research Lab Ltd A dispenser

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US1678540A (en) * 1925-04-28 1928-07-24 Trenner Simeon Pipette
US2685800A (en) * 1952-11-12 1954-08-10 Kopp Scient Inc Pipet for microanalysis
US2974528A (en) * 1957-04-11 1961-03-14 Manuel C Sanz Pipette
US3045494A (en) * 1958-03-13 1962-07-24 Gerarde Horace William Method of providing for blood count and pipette and assembly for use therein
US3285296A (en) * 1956-09-10 1966-11-15 Beckman Instruments Inc Pipette apparatus
US3500689A (en) * 1956-09-10 1970-03-17 American Hospital Supply Corp Pipette construction

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Publication number Priority date Publication date Assignee Title
US1678540A (en) * 1925-04-28 1928-07-24 Trenner Simeon Pipette
US2685800A (en) * 1952-11-12 1954-08-10 Kopp Scient Inc Pipet for microanalysis
US3285296A (en) * 1956-09-10 1966-11-15 Beckman Instruments Inc Pipette apparatus
US3500689A (en) * 1956-09-10 1970-03-17 American Hospital Supply Corp Pipette construction
US2974528A (en) * 1957-04-11 1961-03-14 Manuel C Sanz Pipette
US3045494A (en) * 1958-03-13 1962-07-24 Gerarde Horace William Method of providing for blood count and pipette and assembly for use therein

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3901085A (en) * 1972-11-30 1975-08-26 Jean Marie Faure Pipette or similar apparatus for measuring determined volumes of liquid
US3864979A (en) * 1973-03-30 1975-02-11 Becton Dickinson Co Blood sedimentation tube barrier
US4091802A (en) * 1976-02-17 1978-05-30 Eastman Kodak Company Vented liquid collection device
US4136036A (en) * 1976-04-07 1979-01-23 Eastman Kodak Company Collection and dispensing device for non-pressurized liquids
US4396024A (en) * 1978-11-09 1983-08-02 Sarstedt W Device for the extraction of capillary blood
US4442722A (en) * 1982-02-23 1984-04-17 Beckman Instruments Inc. Plunger operated pipet
US4461328A (en) * 1982-06-04 1984-07-24 Drummond Scientific Company Pipette device
EP0209705A3 (en) * 1985-07-22 1988-06-01 Drummond Scientific Company A disposable preselected-volume capillary pipet device
EP0209705A2 (en) * 1985-07-22 1987-01-28 Drummond Scientific Company A disposable preselected-volume capillary pipet device and method of preparing a liquid sample for testing
US5059398A (en) * 1985-07-22 1991-10-22 Drummond Scientific Company Disposable preselected-volume capillary pipet device
FR2604013A1 (en) * 1986-09-12 1988-03-18 Articles Laboratoire Precision PROCESS FOR CHARACTERIZATION OF A LABORATORY INSTRUMENT AND PIPETTE THUS CHARACTERIZED BY COLORING
EP0261023A1 (en) * 1986-09-12 1988-03-23 Alp Articles De Laboratoire De Precision S.A. Identification method for a laboratory instrument, and pipette identified accordingly by colours
US5065768A (en) * 1988-09-13 1991-11-19 Safe-Tec Clinical Products, Inc. Self-sealing fluid conduit and collection device
US5456885A (en) * 1993-07-12 1995-10-10 Coleman; Charles M. Fluid collection, separation and dispensing tube
US5460782A (en) * 1994-07-18 1995-10-24 Safe-Tec Clinical Products, Inc. Automatic filling micropipette with dispensing means
US20020037239A1 (en) * 2000-09-22 2002-03-28 Fuji Photo Film Co., Ltd. Quantitative suction tip and quantitative suction apparatus
US6343717B1 (en) * 2000-11-21 2002-02-05 Jack Yongfeng Zhang Pre-filled disposable pipettes
US11084030B2 (en) * 2016-04-12 2021-08-10 Gilson Sas Pipette for sampling an extended range of volumes of liquid
WO2023030577A1 (en) * 2021-08-31 2023-03-09 Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung Holder for an individual capillary tube, and collecting device for a plurality of holders

Also Published As

Publication number Publication date
JPS5211600B2 (en) 1977-03-31
JPS4950987A (en) 1974-05-17
DE2324681C2 (en) 1985-10-31
DE1598124A1 (en) 1969-05-22
FR2185051B3 (en) 1976-05-21
DE1598123A1 (en) 1969-09-18
DE2324681A1 (en) 1973-11-29
FR2185051A1 (en) 1973-12-28

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