Peristaltic pump and valve assembly for fluid processing systems

• US 5,484,239 A
• Filed: 12/22/1993
• Issued: 01/16/1996
• Est. Priority Date: 12/22/1993
• Status: Expired due to Term

• Current Assignee: Fenwal Incorporated (Fresenius SE & Co. KGaA)
• Original Assignee: Baxter International Inc.
• Inventors: Chapman, Arthur S., Williamson, Warren P.
• Primary Examiner(s): Bertsch, Richard A.
• Assistant Examiner(s): Korytnyk, Peter G.
• Application Number:
  US08/173,516
• Time in Patent Office: 755 Days
• Field of Search: 417/477 F, 417/477 G, 417/477 B, 417/477 R, 417/474, 417/475, 417/476, 417/477.7, 417/477.8, 417/477.3, 417/477.1
• US Class Current: 417/477.8
• CPC Class Codes: A61M 1/30 Single needle dialysis ; Reciprocating systems, alternately withdrawing blood from and returning it to the patient, e.g. single-lumen-needle dialysis or single needle systems for hemofiltration or pheresis
• CPC Class Codes: A61M 1/303 having a reservoir for treated blood to be returned
• CPC Class Codes: A61M 1/36222 Details related to the interface between cassette and machine
• CPC Class Codes: A61M 1/362227 the interface providing means for actuating on functional elements of the cassette, e.g. plungers
• CPC Class Codes: A61M 1/36224 with sensing means or components thereof
• CPC Class Codes: A61M 1/36225 with blood pumping means or components thereof
• CPC Class Codes: A61M 1/362261 at least one cassette surface or portion thereof being flexible, e.g. the cassette having a rigid base portion with preformed channels and being covered with a foil
• CPC Class Codes: A61M 1/362265 Details of valves
• CPC Class Codes: A61M 1/362266 Means for adding solutions or substances to the blood
• CPC Class Codes: A61M 1/3693 using separation based on different densities of components, e.g. centrifuging
• CPC Class Codes: A61M 1/3696 with means for adding or withdrawing liquid substances during the centrifugation, e.g. continuous centrifugation
• CPC Class Codes: A61M 2205/12 with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: F02B 2075/025 two
• CPC Class Codes: F04B 43/1276 Means for pushing the rollers against the tubular flexible member

Abstract

A peristaltic pump includes a pump race for receiving a flexible tubing. A rotatable pump rotor carries at least one roller for contacting the tubing. A roller locating mechanism moves the pump roller between a retracted position free of contact with the tubing and an extended position making operative contact with the tubing. A controller operates the pump (i) in a pumping mode, during which the rotor is rotated with the roller located in its extended position, and (ii) in a valving mode, during which rotation of the rotor is terminated and the roller is selectively moved between its extended position to block fluid flow through the tubing and its retracted position to permit fluid flow through the tubing. The pump thus provides a peristaltic pump pumping function, as well as serving as a valve element.

Claims

1. A system for processing cellular suspensions comprising

a fluid path for conveying the cellular suspension from source for processing, the fluid path including flexible tubing for engagement with an external peristaltic pumping element,

a peristaltic pumping element for the flexible tubing comprising a pump race for receiving the tubing, a pump rotor carrying at least one roller, and a drive mechanism for rotating the rotor within the pump race,

a roller locating mechanism that moves the pump roller between a retracted position free of contact with the received tubing and an extended position at least partially within the pump race for operative contact with the received tubing,

a controller for operating the peristaltic pumping element

(i) in a pumping mode, during which the rotor is rotated with the roller located in its extended position, and

(ii) in a valving mode, during which rotation of the rotor is terminated and the roller is selectively moved between its extended position to block fluid flow through the flexible tubing and its retracted position to permit fluid flow through the flexible tubing, and,

a valve element operatively associated with the fluid path independent of the peristaltic pumping element for controlling fluid flow through the fluid path, the controller being operable in at least one of the pumping mode and the valving mode for also operating the valve element.

2. A system according to claim 1

wherein the controller is further operable (iii) in a loading mode during which rotation of the rotor is terminated and the roller is moved into its retracted position to receive the flexible tubing within the pump race.

3. A system according to claim 2

and further including a valve element operatively associated with the fluid path independent of the peristaltic pumping element for controlling fluid flow through the fluid path, and

wherein the controller is operable in the loading mode for operating the valve element.

4. A system according to claim 1

wherein the roller locating mechanism includes

an actuating rod that extends along the axis of rotation, the rod having a distal end and a proximal end,

actuator means coupled to the proximal rod end for advancing the rod along the axis of rotation in a forward direction toward the pump rotor and in a rearward direction away from the pump rotor, and

linkage means coupled to the distal rod end for converting advancement of the actuating rod along the axis of rotation in response to the actuator means into movement of the pump roller radially of the axis of rotation between a retracted position free of contact with flexible tubing and an extended position making operative contact with flexible tubing.

5. A system according to claim 4

wherein the linkage means includes

a first link element coupled to the distal rod end for movement in response to advancement of the rod along an axis that is generally parallel to the axis of rotor rotation,

a second link element coupled to the first link element for movement in response to movement of the first link element, the second link element being movable in a plane that is generally perpendicular to the axis of rotor rotation, and

a rocker element coupled to the second link element and carrying the roller for movement in response to movement of the second link element, the rocker element pivoting about an axis to move the roller radially of the axis of rotation.

6. A system according to claim 5

and further including a spring normally urging the roller toward its retracted position.

7. A system according to claim 6

wherein the spring applies tension upon the roller through the rocker element when the roller is in its extended position to accommodate variations in flexible tubing geometry.

8. A system according to claim 1

wherein the roller locating mechanism includes means for biasing the roller toward its retracted position.

9. A system according to claim 8

wherein the biasing means places tension upon the roller when in its extended position to accommodate variations in flexible tubing geometry.

10. A system according to claim 1

wherein the roller locating mechanism includes means for placing tension upon the roller when in its extended position to accommodate variations in flexible tubing geometry.

11. A system according to claim 1

and further including a separation element that communicates with the fluid path for separating cellular material from the suspension.

12. A system for processing cellular suspensions comprising

a fluid path for conveying the cellular suspension from source for processing, the fluid path including flexible tubing for engagement with an external peristaltic pumping element,

a peristaltic pumping element for the flexible tubing comprising a pump race for receiving the tubing, a pump rotor carrying at least one roller, and a drive mechanism for rotating the rotor within the pump race,

a roller locating mechanism that moves the pump roller between a retracted position free of contact with the received tubing and an extended position at least partially within the pump race for operative contact with the received tubing,

a controller for operating the peristaltic pumping element

(i) in a pumping mode, during which the rotor is rotated with the roller located in its extended position, and

(ii) in a valving mode, during which rotation of the rotor is terminated and the roller is selectively moved between its extended position to block fluid flow through the flexible tubing and its retracted position to permit fluid flow through the flexible tubing, and

(iii) in a loading mode during which rotation of the rotor is terminated and the roller is moved into its retracted position to receive the flexible tubing within the pump race, and

a valve element operatively associated with the fluid path independent of the peristaltic pumping element for controlling fluid flow through the fluid path, the controller being operable in the loading mode for operating the valve element.

13. A system according to claim 12

wherein the controller is also operable in at least one of the pumping mode and the valving mode for operating the valve element.

14. A system according to claim 12

wherein the roller locating mechanism includes

an actuating rod that extends along the axis of rotation, the rod having a distal end and a proximal end,

actuator means coupled to the proximal rod end for advancing the rod along the axis of rotation in a forward direction toward the pump rotor and in a rearward direction away from the pump rotor, and

linkage means coupled to the distal rod end for converting advancement of the actuating rod along the axis of rotation in response to the actuator means into movement of the pump roller radially of the axis of rotation between a retracted position free of contact with flexible tubing and an extended position making operative contact with flexible tubing.

15. A system according to claim 14

wherein the linkage means includes

a first link element coupled to the distal rod end for movement in response to advancement of the rod along an axis that is generally parallel to the axis of rotor rotation,

a second link element coupled to the first link element for movement in response to movement of the first link element, the second link element being movable in a plane that is generally perpendicular to the axis of rotor rotation, and

a rocker element coupled to the second link element and carrying the roller for movement in response to movement of the second link element, the rocker element pivoting about an axis to move the roller radially of the axis of rotation.

16. A system according to claim 15

and further including a spring normally urging the roller toward its retracted position.

17. A system according to claim 16

wherein the spring applies tension upon the roller through the rocker element when the roller is in its extended position to accommodate variations in flexible tubing geometry.

18. A system according to claim 12

wherein the roller locating mechanism includes means for biasing the roller toward its retracted position.

19. A system according to claim 18

wherein the biasing means places tension upon the roller when in its extended position to accommodate variations in flexible tubing geometry.

20. A system according to claim 12

wherein the roller locating mechanism includes means for placing tension upon the roller when in its extended position to accommodate variations in flexible tubing geometry.

21. A system according to claim 12

and further including a separation element that communicates with the fluid path for separating cellular material from the suspension.