Infinitely variable pneumatic pulsatile pump

• US 5,924,448 A
• Filed: 04/07/1997
• Issued: 07/20/1999
• Est. Priority Date: 09/29/1993
• Status: Expired due to Term

• Current Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Original Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Inventors: West, Joe E
• Primary Examiner(s): CHAMBERS, A MICHAEL
• Application Number:
  US08/835,201
• Time in Patent Office: 834 Days
• Field of Search: 137/565, 417/395
• US Class Current: 137/565.13
• 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 pneumatic circuit for controlling the flow of a pressurized operating fluid for controlling the supply of working fluid, said circuit comprising:

(a) a pressurized operating fluid source;

(b) a signal generator which generates a plurality of independent, sequential pulsatile signals within said pressurized operating fluid to independently actuate a plurality of compression chambers that supply working fluid such that a continuous supply of working fluid may be supplied by sequentially and alternatingly actuating the compression chambers with said plurality of independent, sequential signals; and

(c) a control valve system arranged to control at least one of said plurality of independent pulsatile signals, wherein said control valve system is capable of selectively disabling said at least one pulsatile signal to thereby cause working fluid to be supplied in a pulsed flow, and said control valve system is in fluid communication with said signal generator.

2. A circuit as in claim 1, wherein said signal generator comprises an adjustable valve arranged to alternate the output of each said plurality of independent pulsatile signals so as to alternatingly produce a pair of sequential independent pulsatile signals, comprising a first independent pulsatile control signal output and a second independent pulsatile control signal output.

3. A circuit as in claim 2, further comprising a variable orifice which is adjustable to vary the pulsating rates of said plurality of pulsatile signals, wherein said variable orifice varies the rate of alternating between said first signal output and said second signal output.

4. A circuit as in claim 2, wherein said adjustable valve comprises at least one condition responsive pneumatic valve having at least two positions and being operatively and fluidly communicated with said supply of operating fluid and said signal generator for producing said pair of independent pulsatile control signal outputs when alternating between said two positions.

5. A circuit as in claim 4, wherein said condition responsive pneumatic valve receives said pressurized operating fluid and alternates said pressurized operating fluid between a first path and a second path in response to predetermined alternating conditions for producing said first independent pulsatile control signal and said second independent pulsatile control signal, respectively, so as to produce said pair of independent pulsatile control signal outputs.

6. A circuit as in claim 5, wherein said control valve system comprises at least one manually actuated pneumatic switch in fluid communication with said at least one condition responsive pneumatic valve for disabling the output of one of said pair of independent pulsatile control signal outputs so as to produce a single pulsatile control signal output, or, alternatively, for enabling the output of said pair of independent pulsatile control signals to produce said pair of independent pulsatile control signal outputs sequentially.

7. A circuit as in claim 4, wherein said control valve system comprises:

a cutoff valve arranged to disable and enable an output of said condition responsive valve to thereby produce a single pulsatile control signal and a pair of pulsatile control signals, respectively.

8. A circuit as in claim 2, wherein said adjustable valve comprises at least one high switching speed pilot valve for receiving said pressurized operating fluid and for generating said pair of independent pulsatile control signals when switching between a first position and a second position, said high switching speed pilot valve being pneumatically actuated between said first position and said second position for generating said first independent pulsatile control signal and said second independent pulsatile control signal, respectively, sequentially.

9. A circuit as in claim 8, wherein said signal generator further comprises at least two signal output control valves actuatable between at least two positions, said at least two signal output control valves being in fluid communication with said high switching speed pilot valve for receiving said pressurized operating fluids so as to alternately produce said first independent pulsatile control signal output and said second independent pulsatile control signal output.

10. A circuit as in claim 9, wherein said high switching speed pilot valve supplies said pressurized operating fluid to said at least two signal output control valves to cause said control valves to alternate between said at least two positions for alternatingly producing said first and second independent pulsatile control signal output.

11. A circuit as in claim 10, wherein said pressurized operating fluid causes said high switching speed pilot valve to actuate.

12. A circuit as in claim 8, comprising:

a first signal output control valve actuatable between at least two positions, said first signal output control valve being in fluid commination with said high switching speed pilot valve for receiving said pressurized operating fluid so as to alternately produce said first independent pulsatile control signal output; and

a second output control valve actuatable between at least two positions, said second signal control valve being in fluid communication with said high switching speed pilot valve for receiving said pressurized operating fluid so as to alternately produce said second independent pulsatile control signal output;

wherein said high switching speed pilot valve alternatingly communicates said pressurized operating fluid between said first condition responsive pilot valve and said second condition responsive pilot valve so as to alternatingly produce said pair of independent pulsatile control signals.

13. A circuit as in claim 12, wherein said high switching speed pilot valve supplies said pressurized operating fluid to said first and second signal output control valves so as to cause said control valves to actuate between said at least two positions for alternatingly producing said first and second independent pulsatile control signal outputs.

14. A circuit as in claim 13, wherein said pressurized operating fluid causes said high switching speed pilot valve to actuate.

15. A circuit as in claim 14, further comprising an oscillation control subcircuit in fluid communication with said high switching speed pilot valve for providing pneumatic feedback to said high switching speed pilot valve from said first and second signal output control valves, wherein said oscillation control subcircuit controls the actuation of said high switching speed pilot valve to alternatingly produce said first and second independent pulsatile control signals in response to said feedback.

16. A circuit as in claim 15, wherein said oscillation control subcircuit comprises a variable orifice which is adjustable to vary the rate of said feedback to said high switching speed pilot valve to thereby vary the rate said high switching speed pilot valve is actuated to vary the pulsating rates of said pair of independent pulsatile control signal outputs.

17. A circuit as in claim 16, wherein said feedback signals are created in said pressurized operating fluid.

18. A circuit as in claim 17, further comprising a pressure controller arranged to adjust the pressure of said pressurized operating fluid.

19. A pneumatic circuit as in claim 1, further comprising:

a large accumulator that supplies operating fluid for actuating the compression chambers;

an adjustable valve arranged to alternate the output of said plurality of independent pulsatile signals to provide a continuous supply of working fluid; and

a small accumulator that supplies fluid for controlling said adjustable valve.

20. A pneumatic circuit as in claim 1, further comprising:

compressible bladders; and

means for supplying said working fluid to said compressible bladders either exclusively from a single supply, or alternatingly from a plurality of supplies.

21. A pneumatic circuit for controlling the flow of pressurized operating fluid for controlling the supply of working fluid, said circuit comprising:

(a) a pressurized operating fluid supply;

(b) two condition responsive pneumatic valves, each actuatable between at least two positions and being operatively and fluidly communicated to said fluid supply for producing a pair of independent sequential pulsatile control signal outputs when alternating between said at least two positions, said independent sequential pulsatile control signals independently and sequentially controlling a corresponding pair of compression chambers that supply working fluid to thereby provide a continuous supply of working fluid;

(c) a control valve system arranged to disable and enable an output of at least one of said condition responsive pneumatic valves to alternatingly produce a single pulsatile control signal that controls only one compression chamber and thereby provides a pulsating supply of working fluid and said pair of independent pulsatile control signal outputs, respectively, to thereby alternate between causing a continuous working fluid supply to be provided and causing a pulsating working fluid supply to be provided; and

(d) an oscillation control subcircuit in fluid communication with said condition responsive pneumatic valves for controlling the rate at which said condition responsive pneumatic valves actuate so as to vary the pulsating rates of said single pulsatile control signal output and said pair of independent pulsatile control signal outputs.

22. A circuit as in claim 21, wherein said oscillation control subcircuit comprises a variable orifice which is adjustable to vary the rate said condition responsive pneumatic valves are actuated for varying the pulsating rates of said pair of independent pulsatile control signal outputs.

23. A circuit as in claim 22, wherein said said control valve system comprises a manually actuated pneumatic switch in fluid communication with one of said pneumatic valves to place said one pneumatic valve into a closed position so as to disable one of said pair of independent pulsatile control signal outputs for generating said single pulsatile control signal output and thereby create a pulsating flow.

24. A circuit as in claim 23, wherein said manually actuated pneumatic switch comprises a two positioned pneumatic pilot valve having a first pilot chamber in fluid communication with a switch which reduces pressure in said first pilot chamber when manipulated so as to cause said pilot valve to actuate into a first position for producing said pair of independent pulsatile pneumatic signal outputs for producing a substantially continuous flow of pressurized operating fluid, and a second pilot chamber in fluid communication with a second switch which relieves pressure in said second pilot chamber when manipulated to cause said pilot valve to actuate into a second position so as to disconnect one of said pneumatic valves from said pressurized operating fluid and thereby Produce a pulse flow of pressurized operating fluid from the other of said pneumatic valves.

25. A circuit as in claim 24, wherein said two pneumatic valves provide pressurized operating fluid as feedback to said oscillation control subcircuit for controlling the timing of actuation of said condition responsive pneumatic valves to alternatingly produce said pair of independent pulsatile control signals at variable rates in response to said feedback, said adjusting means varying the rate said condition responsive pneumatic valve actuates for controlling the rate of said feedback so as to vary the pulsating rates of said pair of independent pulsatile control signal outputs.

26. A pneumatic circuit as in claim 21, further comprising:

a large accumulator that supplies operating fluid for actuating the compression chambers; and

a small accumulator that supplies fluid for controlling said oscillating control subcircuit.