WO1991019903A1 - Pompes de fluides - Google Patents

Pompes de fluides Download PDF

Info

Publication number
WO1991019903A1
WO1991019903A1 PCT/GB1991/000888 GB9100888W WO9119903A1 WO 1991019903 A1 WO1991019903 A1 WO 1991019903A1 GB 9100888 W GB9100888 W GB 9100888W WO 9119903 A1 WO9119903 A1 WO 9119903A1
Authority
WO
WIPO (PCT)
Prior art keywords
fluid
plunger
pump
compartment
chamber
Prior art date
Application number
PCT/GB1991/000888
Other languages
English (en)
Inventor
Richard Graham Fletcher
Original Assignee
Pwm Drives Limited
Neo-Medical Consultants Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pwm Drives Limited, Neo-Medical Consultants Limited filed Critical Pwm Drives Limited
Publication of WO1991019903A1 publication Critical patent/WO1991019903A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B17/00—Pumps characterised by combination with, or adaptation to, specific driving engines or motors
    • F04B17/03—Pumps characterised by combination with, or adaptation to, specific driving engines or motors driven by electric motors
    • F04B17/04—Pumps characterised by combination with, or adaptation to, specific driving engines or motors driven by electric motors using solenoids
    • F04B17/046—Pumps characterised by combination with, or adaptation to, specific driving engines or motors driven by electric motors using solenoids the fluid flowing through the moving part of the motor

Definitions

  • Fluid Pumps This invention relates to fluid pumps and is more particularly, but not exclusively, concerned with intravenous fluid infusion pumps.
  • An infusion pump for intravenous administration of fluid to a patient is known (U.S. Specification No. 3985133) which includes a disposable volumetric cassette for receiving the fluid to be pumped from input tubing and for supplying measured quantities of fluid to output tubing for infusion into the patient.
  • the cassette includes a pump chamber alternately connectable to the input and output tubing by a common inlet/outlet passage and a rotary valve, and a piston reciprocable within the chamber to draw fluid from the input tubing and discharge fluid to the output tubing.
  • the valve and the piston are driven in synchronism by an external motor so as to provide the required pumping action.
  • a fluid pump comprising a housing having a pump chamber provided with a fluid inlet and a fluid outlet at opposite ends of the chamber, a agnetisable plunger reciprocable within the chamber and dividing the chamber into an input compartment adjoining the fluid inlet and an output compartment adjoining the fluid outlet, the plunger having a transfer passage extending therethrough provided for transfer of fluid from the input compartment ⁇ to the output compartment during a predetermined part of the pumping cycle, a first valve member arranged to close off the fluid inlet during transfer of fluid along the transfer passage from the input compartment to the output compartment on displacement of the plunger in one direction, and a second valve member arranged to close off the transfer passage during discharge of fluid from the output compartment through the fluid outlet and during supply of fluid to the input compartment through the fluid inlet on displacement of the plunger in the opposite direction, the plunger being reciprocable by suitable electromagnet means to effect pumping by magnetic action.
  • an advantage of such a pump is that pumping cannot continue when the pump is empty of fluid. Furthermore the pump will not pump any substantial quantities of air. The closing off of the fluid inlet by the first valve member during transfer of fluid along the transfer passage also ensures that siphoning cannot occur through. the pump.
  • a further advantage of such a pump is that the pump and the mechanism for reciprocating the pump may be integrated, the pump plunger itself forming the moving part of the mechanism. This enables the pump housing, which is preferably formed as a replaceable cassette, to be made more compact and at lower cost than in conventional pumps provided for the same purpose.
  • the pump can also be made to be extremely reliable in use, particularly since it does not require use of a bellows-type seal, and to give precise delivery of volume.
  • the controller for operating the pump which will generally be adapted to. receive a cassette which is replaceable after each use, may be made to be particularly reliable in long-term use since it will generally have no moving parts.
  • the pump preferably includes electromagnet means which is adapted to displace the plunger in one direction on application of an energising signal, and spring means, such as a compression spring, which acts to return the plunger in the opposite direction on removal of the energising signal.
  • spring means such as a compression spring
  • the electromagnet means preferably incorporates two opposite magnetisable poles spaced apart in the direction of reciprocating movement of the plunger and positioned such that the plunger is asymmetrically disposed with respect to the poles when in at least one of its limiting positions.
  • the electromagnet means may comprise at least one coil and preferably at least one substantially C- shaped core of magnetisable material having arms defining the poles at their free ends. Additionally a further substantially C-shaped core of magnetisable material may be provided at the ends of each of said arms, the two further cores extending along substantially parallel planes transverse to the direction of reciprocating movement of the plunger and receiving the pump housing between their arms.
  • the housing may be in the form of a replaceable cassette which is easily insertable between the arms. •
  • the first valve member is adapted to float in the fluid supplied to the input compartment to close off the fluid inlet, and the second valve member is adapted to float in the fluid supplied to the output compartment to close off the transfer passage.
  • the valve members are conveniently ball floats.
  • a detector such as an optical detector, is provided to indicate when the pump is empty in dependence on the position of one of the valve members during a predetermined part of the pumping cycle.
  • the invention also provides a fluid pump comprising a housing having a pump chamber, a magnetisable plunger reciprocable within the chamber to effect fluid pumping, and electromagnet means for reciprocation of the plunger by magnetic action, wherein the electromagnet means includes a substantially C-shaped core of magnetisable material having two arms lying on a common plane, and the housing is in the form of a replaceable cassette which is insertable between the arms such that the direction of reciprocating movement of the plunger is transverse to said common plane.
  • Figures 1 and 2 show the pump in axial section in two operating positions
  • Figure 3 is a perspective view on a reduced scale of the pump electromagnet
  • Figure 4 is a schematic circuit diagram of a current source for the pump electromagnet
  • Figure 5 is a perspective view on an enlarged scale of an alternative pump electromagnet
  • Figures 6 and 7 show two variants of the pump in axial section.
  • the pump 1 has a two-part housing 2 made _of transparent plastics material and comprising an upper part 3 having a female connector 4 for connection to input tubing (not shown) and a lower part 5 having a male connector 6 for connection to output tubing (not shown) .
  • the housing 2 is in the form of a replaceable cassette which may be inserted in the central bore 7 of an electromagnet 8 (see Figure 3) so as to extend along an axis 9.
  • the electromagnet 8 ' comprises a substantially C- shaped core 10 and a coil 11 which may be energised by a pulse of unipolar current i.
  • the C-shaped core 10 forms opposite poles 12 and 13 which are spaced apart axially of the housing 2.
  • a further substantially C-shaped core 1 may be provided to balance laterally the magnetic forces on the housing 2 and to increase the magnetic flux, and both cores 10 and 14 are preferably formed from laminated grain-orientated silicon steel.
  • an elongate cylindrical pump chamber 15 having a fluid inlet 16 at its upper end provided with a valve seat 17 and a fluid outlet 18 at its lower end provided with a valve seat 19.
  • a cylindrical plunger 20 made of magnetisable material, such as mild steel suitably plated in order to prevent rusting or magnetic stainless steel, is reciprocable within the chamber 15 and forms the moving part of a solenoid formed by the electromagnet 8 and the plunger 20 . Furthermore the plunger 20 divides the chamber 15 into an input compartment 21 adjoining the inlet 16 and an output compartment 22 adjoining the outlet 18, and is provided with an O-ring 23 to prevent fluid leakage along the sides of the plunger.
  • the plunger 20 has a transfer passage 24 extending axially therethrough provided for transfer of fluid from the input compartment 21 to the output compartment 22 during pumping.
  • a valve seat 25 is provided where the transfer passage 24 opens into the input compartment 21, and a valve seat 26 is provided where the transfer passage 24 opens into the output compartment 22.
  • a first ball float 27 is adapted to float in the fluid in the input compartment 21 and to close off the valve seat 17 and/or the valve seat 25, and a second ball float 28 is adapted to float in the fluid in the output compartment 22 and to close off the valve seat 19 and/or the valve seat 26.
  • the two ball floats 27 and 28 are made of polypropylene or hollow metal.
  • a return compression spring 29 made of stainless steel acts between the lower housing part 5 and the plunger 20 so as to provide return upward movement of the plunger 20 following a downstroke of the plunger 20 effected by energisation of the electromagnet 8 through magnetic action.
  • the output compartment 22 will be filled with the fluid being pumped and this will cause the second ball float 28 to float and to seat against the valve seat 26 thus closing off the outlet opening of the transfer passage 24. In this position the fluid outlet 18 is not closed off by the second ball float 28. Furthermore the plunger 20 is asymmetrically located between the poles 12 and 13 of the electromagnet 8.
  • the spring 29 forces the plunger 20 upwardly thus lifting the valve seat 26 at the outlet opening of the transfer passage 24 away from the second ball float 28 and permitting supply of fluid along the transfer passage 24 to the output compartment 22.
  • the second ball float 28 is lifted by floating in the fluid until it again engages the valve seat 26 thus closing off the transfer passage 24 whilst at the same time opening the fluid outlet 18.
  • the valve seat 25 on the plunger 20 is lifted to engage the second ball float 27 thus closing off the inlet opening of the transfer passage 24.
  • the pump 1 is prevented from pumping air since, when the output compartment 22 is empty, the second ball float 28 will seat against the valve seat 19 thus closing off the fluid outlet 18. Because th*& floating properties of the ball floats 27 and 28 form an integral part of the pump operation, the pump must generally be orientated in a near vertical position. Furthermore, as the electromagnet coil • l O -
  • the coil 11 is supplied from a controlled current source, as shown in Figure 4, comprising an operational amplifier 30, a transistor 30A, a current sense resistor 31, a resistor 32 and a diode 33 to dissipate current.
  • a controlled current source as shown in Figure 4, comprising an operational amplifier 30, a transistor 30A, a current sense resistor 31, a resistor 32 and a diode 33 to dissipate current.
  • electromagnet 40 In many applications the necessity to load the pump housing 2 on replacement of the cassette through the electromagnet bore 7 may be undesirable, and in such applications it is preferred that an alternative form of electromagnet 40 is used as shown in Figure 5.
  • this electromagnet 40 two substantially C-shaped cores 41 and 42 extend along substantially parallel planes perpendicular to the pump axis 43, that is the direction of reciprocating movement of the plunger.
  • the cores 41 and 42 define the poles of the electromagnet and are each positioned with their -arms embracing the housing 2.
  • the cores 41 and 42 are electromagnetically arranged in conjunction with a further substantially C-shaped core 44 around which the coil 45 is wound.
  • the state of the pump being empty of fluid may be detected in two ways. If the volume of fluid to be supplied by the pump is known, and since the pump has a fixed stroke, the number of strokes may be counted until the calculated volume to be supplied is reached. When this is indicated by a count output signal, pumping is stopped by deactivation of the electromagnet and an empty condition is signalled.
  • an optical detector may be used to indicate when the pump is empty in dependence on the position of the second ball float 28, as shown schematically in Figure 6.
  • the optical detector comprises a light source 50 and a light receiver 51 both of which are external to the pump and form part of a main controller used to control the pump electrically.
  • the second ball float 28 should float in the fluid in the output compartment 22 immediately before each downstroke of the plunger 20 thus interrupting the light beam between the source 50 and receiver 51.
  • the second ball float 28 will no longer float but will be in a position 28' indicated by broken lines in Figure 6.
  • the second ball float 28 will no longer interrupt the light beam at this point in the pump cycle and detection of the light beam by the receiver.51 will cause a pump empty condition to be signalled.
  • the source 50 and- receiver 51 would need to be embedded in the coil 11, or alternatively an extra float chamber would have to be used requiring use of additional pump components.
  • suitable design of the pump it is possible to allow for use of the pump at angles greater than say 15° from the vertical.
  • the shape of the input compartment 21 in conjunction with the size of the first ball float 27 permits operation with large angles from the vertical.
  • a modification of the second ball float 28, as shown in Figure 7, may be necessary to permit use over a wide operating angle.
  • a stem 60 is provided on the second ball float 28 which protrudes into the " transfer passage 24 so as to ensure correct location of the second ball float 28 over a wide angle range.
  • the cross-section of the stem 60 is chosen such that fluid flow in the transfer passage is not significantly effected.
  • a similar stem arrangement may also be provided on the first ball float 27 if required.
  • a plastics retaining washer 61 having a serrated inner profile is positioned in the input compartment- 21 so that the ball float 27 seats on the washer 61 rather than on a valve seat 25 at the top of the transfer passage 24 on supply of fluid through the fluid inlet 16. Because of the shape of the inner profile of the washer 61, fluid can pass beyond the ball float 27 when it is seated on the washer 61. The use of such a washer not only permits operation of the pump at an increased angle from the vertical, but also decreases the settling time of the ball float 27 in operation. Alternatively the function of the washer 61 could be performed by a check valve spring.
  • a microprocessor controller can be used to perform all calculations, interpret conditions and handle user inputs and outputs.
  • the above-described pump arrangements are particularly advantageous for use in intravenous fluid infusion since they incorporate a replaceable cassette providing a sealed, sterile and non-pyrogenic fluid path, and since the pump is self-priming, non-siphoning and dry- running proof and operates by positive pressure with low fluid pulsation and no back pressure and provides precise volume delivery. Furthermore the pump is compact, requires no maintenance or alignment and can be loaded with the removable cassette quickly and without difficulty. If requiaed the volume supply per stroke can be varied by varying the plunger diameter.
  • the pump is of broadly similar construction to the pump of Figures 1 and 2 except that it is arranged the other way up and both floats are replaced by non-magnetic steel balls.
  • the fluid is sucked upwardly through the pump, and the balls are acted upon by gravity to close off the inlet and the transfer passage respectively at appropriate times during the pumping cycle.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Electromagnetic Pumps, Or The Like (AREA)

Abstract

Une pompe (1) pour l'infusion intraveineuse d'un liquide comporte un logement (2) contenant une chambre de pompage (15) pourvue d'une arrivée de fluide (16) et d'une sortie de fluide (18), et d'un piston magnétisable (20) pouvant être déplacé réciproquement dans la chambre à l'aide d'un électro-aimant externe (8) et divisant la chambre en un compartiment d'arrivée (21) et un compartiment de sortie (22). Le piston (20) possède un passage de transfert (24) qui le traverse et permet le transfert du fluide du compartiment d'arrivée (21) au compartiment de sortie (22) au cours du pompage. Un premier flotteur (27) flottant dans le fluide est ménagé dans le compartiment d'arrivée (21) afin de fermer l'arrivée (16) au cours du transfert de fluide le long du passage de transfert (24) du compartiment d'arrivée (21) au compartiment de sortie (22) lorsque le piston (20) est déplacé dans une direction, et un second flotteur (28) flottant dans le fluide est ménagé dans le compartiment de sortie (22) afin de fermer le passage de transfert (24) au cours de l'évacuation du fluide du compartiment de sortie (22) à travers la sortie (18) et au cours de l'alimentation de fluide au compartiment d'arrivée (21) à travers l'arrivée (16) lorsque le piston est déplacé dans la direction opposée. L'action de pompage d'une telle pompe est avantageuse en ce que le pompage ne peut continuer lorsque la pompe est vide et celle-ci ne continuera pas à pomper des quantités importantes d'air. La pompe est en outre de forme compacte et de fabrication peu coûteuse.
PCT/GB1991/000888 1990-06-16 1991-06-04 Pompes de fluides WO1991019903A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9013499.0 1990-06-16
GB909013499A GB9013499D0 (en) 1990-06-16 1990-06-16 Fluid pumps

Publications (1)

Publication Number Publication Date
WO1991019903A1 true WO1991019903A1 (fr) 1991-12-26

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ID=10677758

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1991/000888 WO1991019903A1 (fr) 1990-06-16 1991-06-04 Pompes de fluides

Country Status (2)

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GB (1) GB9013499D0 (fr)
WO (1) WO1991019903A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000061946A1 (fr) * 1999-04-09 2000-10-19 Ulka Srl Piston composite pour pompe vibrante
EP1305522A1 (fr) * 2000-07-28 2003-05-02 Sarcos LC Circuit de pompage de resonateur
EP1503078A1 (fr) * 2003-07-30 2005-02-02 INVENSYS CONTROLS ITALY Srl Pompe électromagnétique
WO2009083179A1 (fr) * 2008-01-02 2009-07-09 Hahn-Schickard-Gesellschaft für angewandte Forschung e.V. Dispositif fluidique pour la manipulation contrôlée de liquides et système fluidique équipé d'un dispositif fluidique
CN103016291A (zh) * 2012-08-13 2013-04-03 镇江七政新能源有限公司 一种置于管内的活塞泵

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114573168B (zh) * 2022-04-08 2022-12-02 湖北灵坦机电设备有限公司 一种带有自动加药功能的污水处理设备

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2925814A (en) * 1956-10-30 1960-02-23 Foster L Vibber Transfusion apparatus
FR1344504A (fr) * 1962-10-19 1963-11-29 Commissariat Energie Atomique Pompe à piston libre
FR1413629A (fr) * 1964-11-06 1965-10-08 Procédé notamment pour le nettoyage des pare-brise ou autres applications et dispositif pour la mise en oeuvre de ce procédé ou procédé similaire
US3299818A (en) * 1964-02-20 1967-01-24 Meyer Ernst Submersible pump
US4103686A (en) * 1977-03-29 1978-08-01 Burron Medical Products, Inc. Dual valve assembly
WO1983002561A1 (fr) * 1982-01-27 1983-08-04 George Alfred Braisby Austin Commande de debit pour des solutions intraveineuses
DE3821320A1 (de) * 1988-06-24 1989-12-28 Teves Gmbh Alfred Druckmittelquelle fuer eine hydraulische anlage, insbesondere bremsanlage

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2925814A (en) * 1956-10-30 1960-02-23 Foster L Vibber Transfusion apparatus
FR1344504A (fr) * 1962-10-19 1963-11-29 Commissariat Energie Atomique Pompe à piston libre
US3299818A (en) * 1964-02-20 1967-01-24 Meyer Ernst Submersible pump
FR1413629A (fr) * 1964-11-06 1965-10-08 Procédé notamment pour le nettoyage des pare-brise ou autres applications et dispositif pour la mise en oeuvre de ce procédé ou procédé similaire
US4103686A (en) * 1977-03-29 1978-08-01 Burron Medical Products, Inc. Dual valve assembly
WO1983002561A1 (fr) * 1982-01-27 1983-08-04 George Alfred Braisby Austin Commande de debit pour des solutions intraveineuses
DE3821320A1 (de) * 1988-06-24 1989-12-28 Teves Gmbh Alfred Druckmittelquelle fuer eine hydraulische anlage, insbesondere bremsanlage

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000061946A1 (fr) * 1999-04-09 2000-10-19 Ulka Srl Piston composite pour pompe vibrante
US6554588B1 (en) 1999-04-09 2003-04-29 Ulka Srl Composite piston for a vibration pump
EP1305522A1 (fr) * 2000-07-28 2003-05-02 Sarcos LC Circuit de pompage de resonateur
EP1305522A4 (fr) * 2000-07-28 2004-08-11 Sarcos Lc Circuit de pompage de resonateur
EP1593847A2 (fr) * 2000-07-28 2005-11-09 Sarcos LC Système de pompage résonant
EP1593847A3 (fr) * 2000-07-28 2005-11-30 Sarcos LC Système de pompage résonant
EP1503078A1 (fr) * 2003-07-30 2005-02-02 INVENSYS CONTROLS ITALY Srl Pompe électromagnétique
WO2009083179A1 (fr) * 2008-01-02 2009-07-09 Hahn-Schickard-Gesellschaft für angewandte Forschung e.V. Dispositif fluidique pour la manipulation contrôlée de liquides et système fluidique équipé d'un dispositif fluidique
CN103016291A (zh) * 2012-08-13 2013-04-03 镇江七政新能源有限公司 一种置于管内的活塞泵

Also Published As

Publication number Publication date
GB9013499D0 (en) 1990-08-08

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