Infinitely variable pneumatic pulsatile pump

• US 5,487,649 A
• Filed: 09/29/1993
• Issued: 01/30/1996
• Est. Priority Date: 09/29/1993
• Status: Expired due to Term

• Current Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Original Assignee: American Hydro-Surgical Instruments, Inc. (Becton, Dickinson & Co)
• Inventors: Dorsey, James H. III, West, Joe E.
• Primary Examiner(s): Bertsch, Richard A.
• Assistant Examiner(s): Wicker, William
• Application Number:
  US08/128,850
• Time in Patent Office: 853 Days
• Field of Search: 417/384, 417/379, 417/394, 417/395, 417/426, 417/46, 604/153
• US Class Current: 417/395
• CPC Class Codes: F04B 43/06 Pumps having fluid drive
• CPC Class Codes: F04B 43/10 Pumps having fluid drive
• CPC Class Codes: F04B 53/1065 fixed at its centre
• CPC Class Codes: Y10T 137/86002 Fluid pressure responsive

Abstract

A pulsatile pump the output of which is infinitely variable between a slow pulsatile flow and increased up to a sharply pulsed flow rate until the pulses run together and a smooth flow results, and which may be varied between wide output pressure and frequency limits. The pump is comprised of a pneumatic control circuit, at least two pneumatically isolated compression chambers, and a novel inlet/outlet pump cartridge and condition-responsive locking means. Operation of the pump is controlled by the use of novel tactile pneumatic response switches. Each compression chamber is communicated with a supply of working fluid through the cartridge. Means are provided for varying the operation of the pneumatic circuit and hence the pump. A flow of pressurized fluid, such as air or nitrogen, is used as the operating media of the pneumatic circuit, although other fluids may be used. Means for monitoring and adjusting pump system parameters are also provided. The pump operates entirely through the use of pneumatic energy, avoiding the use of electricity.

Claims

1. A variable pneumatic pulsatile pump comprising:

a pump means including at least two pneumatically independent compression chambers independently and fluidly communicating with a supply of pressurized operating fluid;

a pneumatic control circuit in fluid communication with said pump means for controllably communicating said pump means with said pressurized operating fluid so as to variably and selectively supply and deprive said compression chambers with said pressurized operating fluid; and

at least one supply of working fluid to be selectively admitted to and ejected from said pump means in response to said pneumatic control circuit.

2. The pump of claim 1, wherein said pneumatic control circuit is comprised of:

a means for supplying said compressed operating fluid independently to said at least two compression chambers from a single supply of compressed operating fluid; and

means for alternatingly supplying and depriving said means for supplying with pressurized operating fluid, switchable between a first, flow, state when working fluid is being discharged from said pump means and a second, no-flow, state when working fluid is not being discharged from said pump means.

3. The pump of claim 2, wherein said means for supplying is comprised of an oscillatory sub-circuit, the oscillation rate of which is adjustable.

4. The pump of claim 2, wherein said means for alternatingly supplying and depriving includes a pilot valve.

5. The pump of claim 2, further comprising sensing means responsive to the difference in pressure within the pressurized operating fluid and the pressure within the working fluid downstream of said pump means, said sensing means being fluidly communicated with said means for supplying and depriving.

6. The pump of claim 5, further comprising means for disconnecting at least one of said compression chambers from said pressurized operating fluid while said pump is in use.

7. The pump of claim 6, wherein said means for disconnecting includes at least one pilot valve.

8. The pump of claim 6, wherein working fluid is supplied to said pump means from at least two independent sources, the pump further comprising:

means for switching between working fluid supplies, such that working fluid can be supplied to the pump means exclusively from a first supply thereof, or, alternatively, exclusively from a second supply thereof, etc., or, further alternatively, from more than one supply thereof at one time.

9. The pump of claim 8, wherein said means for switching includes at least one pilot valve.

10. A pneumatic pump element, comprising:

at least two pneumatically independent compression chambers;

a plurality of compressible bladders, one associated with each compression chamber adapted to receive and eject a quantity of working fluid;

a pump cartridge communicating each bladder with at least one supply of working fluid; and

means for selectively supplying compressed operating fluid to each compression chamber to selectively compress any one of said bladders to cause working fluid to be ejected through a discharge of said cartridge.

11. The pump of claim 10, further comprising:

first means for preventing reverse flow of working fluid from said bladders toward an inlet of said cartridge;

second means for preventing reverse flow of working fluid from a discharge defined by said cartridge into said bladders; and

a resilient diaphragm isolating said cartridge discharge from said cartridge inlet when in a first, sealing, position and allowing communication between said cartridge discharge and said cartridge inlet when in a second, venting, position.

12. The pump of claim 11, wherein said pump cartridge is comprised of a lower body member adapted to mate with at least a portion of said compressible bladders, a middle body member defining said cartridge inlet and said cartridge outlet, and an upper body member adapted to sandwich said diaphragm against said middle body member.

13. The pump of claim 11, wherein said means for preventing reverse flow of working fluid from said bladders to said working fluid sources are each comprised of at least one one-way check valve corresponding to each bladder, and said means for preventing reverse flow of working fluid from said cartridge discharge to said bladders are each comprised of at least one one-way check valve corresponding to each bladder.

14. The pump of claim 13, further comprising means communicating the cartridge discharge with the cartridge inlet when the diaphragm is in the venting position.

15. The pump of claim 14, wherein said means communicating the cartridge discharge with the cartridge inlet is a fluid flow passageway defined by the cartridge.

16. An infinitely variable pneumatic pulsatile pump, comprising:

a housing;

a pneumatic control circuit associated with said housing;

means for controlling the function of said circuit associated with said housing;

a pump inlet/outlet cartridge;

at least two pneumatically independent compression cylinders, each defining its own compression chamber, each said compression chamber being fluidly communicated with said pneumatic circuit;

a plurality of compressible bladders, one associated with each of said compression chambers, each said bladder defining a working fluid receiving interior volume fluidly communicated with said cartridge;

each said cylinder being pivotally connected to said housing between a first, use, position, and a second, cartridge/bladder removal, position;

means for locking said cartridge and cylinders into the use position reciprocally movable with respect to said housing between a first, cartridge/bladder locking, position, and a second, cartridge/bladder release, position;

said pneumatic circuit being fluidly communicated with a supply of pressurized operating fluid; and

said pneumatic circuit selectively, but controllably communicating said pressurized operating fluid with said compression chambers to at least partially collapse said bladders and thereby eject working fluid from said cartridge as desired.

17. The pump of claim 16, wherein said pneumatic circuit is adjustable so as to cause working fluid to be ejected from said cartridge in a pulsating flow, or to cause working fluid to be ejected in a smooth flow, or any combination thereof.

18. The pump of claim 17, wherein said means for locking is comprised of:

a piston/cylinder arrangement defining a piston lowering volume and a piston raising volume, said piston being movable relative to said cylinder between the cartridge/bladder locking position and the cartridge/bladder release position by the introduction of pressurized operating fluid into either the piston lowering volume or the piston raising volume, respectively.

19. The pump of claim 18, wherein:

said cartridge defines an inlet chamber fluidly communicated with a source of working fluid via at least one cartridge inlet passageway;

said cartridge further defining an outlet chamber fluidly communicated with a point-of-use instrument means via a cartridge discharge passageway;

said cartridge inlet and outlet chambers being fluidly communicated with the interior of each of said bladders via inlet and outlet working fluid passageways, respectively;

at least one check valve means disposed across each working fluid passageway so that working fluid is permitted to flow only from the cartridge inlet into each bladder interior in one direction, and thereafter ejected upon compression of said bladders through said outlet working fluid passageways toward said cartridge outlet chamber;

said inlet and outlet chambers being selectively fluidly communicated with each other via a pressure release passageway; and

a resilient diaphragm means normally sealing said pressure release passageway.

20. The pump of claim 19, wherein said piston arrangement of said locking means defines a sensor nose adapted to contact said diaphragm when working fluid pressure in the discharge chamber of said cartridge is greater than the operating fluid pressure present at said sensor nose, under which condition compressed operating fluid is prevented from entering any of said compression chambers.