Pump cassette and method of pumping

• US 5,237,309 A
• Filed: 06/19/1989
• Issued: 08/17/1993
• Est. Priority Date: 07/20/1987
• Status: Expired due to Term

• Current Assignee: Frantz Medical Development Ltd. (Frantz Medical Group)
• Original Assignee: Frantz Medical Development Ltd. (Frantz Medical Group)
• Inventors: Shen, Ying, Sears, Lawrence M., Frantz, Mark G., Pavsek, Thomas J., Honard, Mark R.
• Primary Examiner(s): Swann, III, Glen R.
• Assistant Examiner(s): Mullen, Jr., Thomas J.
• Application Number:
  US07/368,375
• Time in Patent Office: 1,520 Days
• Field of Search: 340/679, 340/606-608, 340/626, 340/612, 340/619, 340/568, 340/636, 604/153, 604/67, 604/123, 137/493.1, 417/437, 417/566, 417/472-473, 417/63, 417/412-413, 92/130, 222/325
• US Class Current: 340/679
• CPC Class Codes: A61M 2205/12 with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 2205/128 with incorporated valves
• CPC Class Codes: A61M 5/14216 Reciprocating piston type
• CPC Class Codes: A61M 5/16854 by monitoring line pressure

Abstract

A medical pumping system has a supply tube (2), an outlet tube (6), a readily sterilizable, disposable cassette (3) connected to the tubes and engaged with the pump, and means (22,24) such as a motor-driven piston, for intermittently applying pressure to the cassette. The pumping system features a display and switch means (9, 10) on a front panel thereof, a pressure sensor (28), an optical fluid presence sensor (19), and a microprocessor (20) metering the volume of fluid pumped through said cassette (3), monitoring output signals from said sensors (18, 28), controlling the motor-driven piston in accordance with settings entered via said switch means (9,10), and directing output data to said display means (8). The microprocessor has a stored program for performing SET RATE, RUN, HOLD, VOLUME FED, and CLEAR VOLUME functions. The cassette includes a hydraulically self-actuating inlet valve (44) communicating with the supply tube (2), a hydraulically self-actuating outlet check valve (42) communicating with, and preventing backflow from, the outlet tube (6), a hollow, resilient compressible member, such as a bellows (34) having an interior communicating with the inlet and outlet valves, and a support structure (30,36,38) securing together the tubes, valves and bellows in operating relation. Preferably, the inlet and outlet valves are a unitary element.

Claims

1. A readily sterilizable cassette, for use in a continuous pumping system having a supply tube (2), an outlet tube (6), and means (22,24) for intermittently applying pressure to said cassette, comprising:

a hydraulically self-actuating inlet valve (44) communicating with said supply tube (2);

a hydraulically self-actuating outlet valve (42) communicating with said outlet tube (6);

a hollow, resilient, self-returning compressible member (34) having an interior communicating, for sterility reasons, only with said inlet and outlet valves; and

a support structure (30,36,38) securing together said tubes, valves and compressible member in operating relation;

said compressible member opening said outlet valve (42) and expelling fluid therethrough, in response to pressure from said means (22,24) for intermittently applying pressure, said compressible member (34) resiliently expanding in the absence of pressure from said means (22,24) for intermittently applying pressure, thereby opening said hydraulically self-actuating inlet valve (44) and drawing fluid from said supply tube (2).

2. The cassette of claim 1, wherein said inlet valve (44) and said outlet valve (42) comprise a unitary element (40).

3. The cassette of claim 2, wherein said unitary element (40) has a generally umbrella-shaped surface and a generally cylindrical axial stem (41), said outlet valve (42) being disposed in said stem, and an outer rim (45) of said umbrella-shaped surface forming said inlet valve (44).

4. The cassette of claim 2, wherein said compressible member is a bellows (34).

5. The cassette of claim 1, wherein said compressible member (34) defines a specific volume therewithin which is expelled upon each compression thereof.

6. The cassette of claim 1, wherein said compressible member is a bellows (34).

7. The cassette of claim 1, wherein said support structure comprises a bellows retainer (30) and a valve retainer (36) secured together.

8. The cassette of claim 7, wherein said retainers are secured together by sonic welding.

9. The cassette of claim 7, wherein said bellows (34) is generally cylindrical and formed with a peripheral rim at an open end thereof, and said bellows retainer (30) is formed with an annular chamber (32) receiving said peripheral rim.

10. The cassette of claim 7, wherein said support structure further comprises a cap (38) formed with cylindrical apertures interfitting with said supply tube (2) and said outlet tube (6).

11. The cassette of claim 7, wherein said valve retainer (36) is formed with a retaining lip for positioning and latching said cassette within a pump housing.

12. The cassette of claim 1, wherein said support structure (30,36,38) comprises a rigid thermoplastic material.

13. The cassette of claim 1, wherein said outlet valve (42) comprise a duck-bill valve.

14. The cassette of claim 1, wherein said inlet valve comprises an umbrella-shaped flexible element (44,45) in a bowl-shaped chamber (31).

15. The cassette of claim 1, wherein said cassette includes means (38) having an irregular shape which fits into a pump housing (5) only in a unique, correct orientation.

16. The cassette of claim 15, wherein said means (38) having an irregular shape is formed with means for gripping.

17. A readily sterilizable cassette, for use in a pumping system having a supply tube (2), an outlet tube (6), and means (22,24) for intermittently applying pressure to said cassette, comprising:

an optical path formed in said cassette and having variable transmission properties, depending upon whether said supply tube (2) contains fluid, thereby permitting external detection (18,

     19) of fluid supply exhaustion;

a hydraulically self-actuating inlet valve (44) communicating with said supply tube (2);

a hydraulically self-actuating outlet valve (42) communicating with said outlet tube (6);

a hollow, resilient, self-returning compressible member (34) having an interior communicating, for sterility reasons, only with said inlet and outlet valves; and

a support structure (30,36,38) securing together said tubes, valves and compressible member in operating relation;

said compressible member opening said outlet valve (42) and expelling fluid therethrough, in response to pressure from said means (22,24) for intermittently applying pressure, said compressible member (34) resiliently expanding in the absence of pressure from said means (22,24) for intermittently applying pressure, thereby opening said hydraulically self-actuating inlet valve (44) and drawing fluid from said supply tube (2).

18. In a pumping system having a supply tube (2), an outlet tube (6), and a cassette (3) including

a hydraulically self-actuating inlet valve (44) communicating with said supply tube (2);

a hydraulically self-actuating outlet valve (42) communicating with said outlet tube (6);

a hollow, resilient compressable member (34) having an interior communicating with said inlet and outlet valves; and

a support structure (30,36,38) securing together said tubes, valves and compressible member in operating relation;

and means (22,

     24) for applying pressure to said cassette, a method of pumping, comprising the steps of repeatedly

providing a supply of fluid in said supply tube (2);

applying pressure to compress said compressible member (34);

permitting said compressible member to resiliently expand, thereby opening said hydraulically self-actuating inlet valve (44) and causing fluid to flow from said supply tube (2) into said compressible member (34); and

again applying pressure to said compressible member (34), thereby closing said inlet valve (44) while opening said outlet valve (42) and causing fluid to flow from inside said compressible member (34) into said outlet tube (6).