Peristaltic pump

• US 4,673,334 A
• Filed: 02/03/1986
• Issued: 06/16/1987
• Est. Priority Date: 05/25/1984
• Status: Expired due to Term

• Current Assignee: Isco, Inc. (Teledyne Technologies Incorporated)
• Original Assignee: Isco, Inc. (Teledyne Technologies Incorporated)
• Inventors: Allington, Robert W., Hull, John D.
• Primary Examiner(s): Vrablik, John J.
• Application Number:
  US06/825,690
• Time in Patent Office: 498 Days
• Field of Search: 417/474-477, 417/53
• US Class Current: 417/53
• CPC Class Codes: F04B 43/1292 Pumps specially adapted for several tubular flexible members

Abstract

To increase precision of flow in multiple channels of a peristaltic pump, a plurality of spring biased cassettes are mounted to cooperate with a spool having a plurality of elongated rollers which orbit about its center so that each elongated roller in succession compresses a plurality of flexible tubes in the channels against corresponding cam surfaces in the cassettes, spaced from the rollers by surfaces of the cassettes which are in contact with the rolles. In each cassette, the cam is mounted between side plates against which the rollers roll, which are spring biased against the rollers and hinged at a center location to provide precision determined only by the precision of the cam to side plate edge dimension. The cam is shaped to reduce pulses during roller lift-off from the cam surface to provide for pulse-free flow.

Claims

1. A method of pumping comprising the steps of:

orbiting a plurality of rollers about a drive shaft in a circular orbit;

positioning each of a plurality of flexible tubes in a corresponding one of a plurality of tube supports against a corresponding cam surface wherein each of the tube supports has mounted to it a corresponding guide surface spaced a programmed distance from the cam surface;

resiliently mounting at least some of said guide surfaces against said rollers independently from the other guide surfaces wherein said tubes are compressed to a programmed degree along their lengths and said at least some of said guide surfaces are movable with respect to other of said guide surfaces during pumping.

2. A method of pumping comprising the steps of:

orbiting a plurality of rollers about a drive shaft in a circular orbit;

positioning each of a plurality of flexible tubes in a corresponding one of a plurality of tube supports against a corresponding cam surface wherein each of the tube supports has mounted to it a corresponding guide surface spaced a programmed distance from the cam surface; and

resiliently mounting said guide surfaces against said rollers, wherein said tubes are compressed to a programmed degree along their lengths;

the step of resiliently mounting including spring biasing two halves of the tube supports apart at pivotable hinge means.

3. A method of pumping in accordance with claim 2 comprising the step of positioning a guide surface with respect to said rollers so that the rollers are spaced apart at least one-quarter of the length of the shortest guide surface between an end and a hinged point and less than three-quarters of the total length whereby said tube is not compressed until just before it begins releasing the tube near said outlet end.

4. A method of pumping comprising the steps of:

orbiting a plurality of rollers about a drive shaft in a circular orbit;

positioning each of a plurality of flexible tubes in a corresponding one of a plurality of tube supports against a corresponding cam surface wherein each of the tube supports has mounted to it a corresponding guide surface spaced a programmed distance from the cam surface;

resiliently mounting said guide surfaces against said rollers, wherein said tubes are compressed to a programmed degree along their lengths; and

positioning a guide surface with respect to said rollers so that the rollers are spaced apart at least one-quarter of the length of the shortest guide surface between an end and a hinged point and less than three-quarters of the total length whereby said tube is not compressed until just before it begins releasing the tube near said outlet end.

5. Apparatus comprising:

a cassette for a peristaltic pump;

said peristaltic pump having rollers;

said cassette having means for receiving at least one peristaltic pump tube and being adapted to cooperate with other cassettes on the same peristaltic pump;

said cassette including means for providing multiple degree of freedom of motion for the cassette with respect to the rollers and other cassettes on the pump while the peristaltic pump operates, whereby the cassette contacts multiple rollers regardless of small errors in the dimensions of the cassette and in the location of the rollers; and

said means for providing multiple degrees of freedom of motion for the cassette including a hinge permitting flexing about a central location and spring means for resiliently mounting the ends of the cassette over the rollers.

6. Apparatus in accordance with claim 5 in which the means for providing includes means for providing three degrees of freedom of motion which are:

side-to-side, up and down and flexation about said central hinge whereby the cassette contacts at least three rollers simultaneously despite small errors in dimension and location.

7. Apparatus in accordance with claim 5 in which the means for providing includes means for providing four degrees of freedom of motion whereby the cassette contacts at least four rollers simultaneously despite small errors in dimension and location.

8. Apparatus in accordance with claim 5 in which the means for providing includes means for providing multiple degrees of freedom motion whereby the cassette contacts as many rollers as there are degrees of freedom despite small errors in dimension and location.

9. Apparatus in accordance with claim 5 including:

a plurality of tube-holding means;

a plurality of cassettes substantially identical to said first-mentioned cassette, each having a corresponding one of a plurality of said tube-holding means;

each of said tube-holding means including a corresponding one of a plurality of first and second surfaces;

said peristaltic pump tube being a flexible tube;

one of each of said first and second surfaces spacing the corresponding other one of said first and second surfaces from said rollers and the other being a surface adapted to bear against the flexible tube;

whereby each of said tube-holding means is movable independently from the other tube-holding means.

10. Apparatus in accordance with claim 9 further including:

a corresponding plurality of spring means for resiliently mounting the ends of each of a corresponding plurality of ends of the corresponding plurality of cassettes over the rollers;

said one of each of said first and second surfaces including a guide surface held against said rollers by said corresponding spring means and having a curvature identical to the curvature of the outer reach of the orbit of said rollers;

said other of said first and second surfaces being shaped to vary in distance from said one of said first and second surfaces in accordance with said controlled sequence of degree of squeezing of the tube by rollers.

11. Apparatus according to claim 10 in which at least some of the tube-holding means are in at least two sections connected by a hinge means, the distance between the first and second surface approximately 90 degrees from the hinge means being substantially equal to the outer diameter of the corresponding tube, said distance becoming less to a point approximately 63 degrees from the hinge means at which point it is substantially twice the thickness of the walls of the tube;

at a point between the hinge means and 63 degrees, the distance is less than twice the thickness of the walls of the tube; and

from approximately 5 degrees beyond the hinge means to 90 degrees beyond the hinge means the distance becomes successively greater than said distance less than twice the thickness of the tube.

12. Apparatus in accordance with claim 10 in which the distance of the two surfaces from each other with respect to degrees of rotation is substantially as shown in FIG. 4.

13. A cassette in accordance with claim 10 in which the distance of the two surfaces from each other with respect to degrees of rotation is as shown in FIG. 4.

14. A cassette for a peristaltic pump adapted to include at least one flexible tube through which fluid flows having rollers adapted to squeeze said at least one tube to cause pumping of a fluid therethrough, comprising:

at least one tube-holding means for providing a controlled sequence of different degrees of squeezing of said at least one flexible tube by the rollers based on the position of the rollers with respect to the tube-holding means;

said tube-holding means including spring means for biasing said cassette against said rollers; and

at least first and second surfaces;

one of said first and second surfaces spacing the other from said rollers;

the other of said first and second surfaces being adapted to bear against a flexible tube;

said spring means being releasable;

said at least one tube-mounting means including first mounting and second mounting means;

said first and second mounting means being pivoted at a central location; and

said spring means including at least one biasing means for resiliently and releasably biasing said first and second mounting means against said rollers and at least a second biasing means for resiliently biasing said first and second mounting means apart.

15. A peristaltic pump comprising:

a motor;

a drive shaft for said motor having a drive shaft axis;

first and second flanges mounted orthogonally to said drive shaft for rotataion therewith;

a plurality of rollers rotatably mounted to said flanges for orbiting about the axis of said drive shaft while being free to rotate in said flanges about their axes;

a tube holding means;

said tube holding means having mounted to it a cam surface means having a cam surface adapted to receive a tube;

spring means for mounting said tube holding means to said peristaltic pump;

a guide surface means having a guide surface;

said cam surface being spaced from said rollers by said guide surface;

said guide surface means being connected to the cam surface means;

a flexible tube having a length and a flexible wall;

said tube corresponding in position along a portion of its length to the cam surface;

said tube holding means including at least one inlet and outlet tube holding means and said spring means including at least one means for spring biasing said inlet and outlet tube holding means and at least one pivoted hinge means;

said cam surface means including inlet cam means mounted to said inlet tube holding means and outlet cam means mounted to said outlet tube holding means;

said guide surface and plurality of rollers having dimensions such that successive rollers contact at least one-quarter of the guide surface between one end of the guide surface and the pivoted hinged means and less than three-quarters of the total guide surface whereby said tube is not compressed by each of said successive rollers until just before said each of said successive rollers begins releasing the tube near said outlet end; and

the distance between said cam surface and the corresponding location on said guide surface changing from a distance less than twice the thickness of said wall of said tube to the diameter of said tube.

16. A peristaltic pump in accordance with claim 15 in which:

said tube holding means includes a plurality of tube holding stations;

said cam surface means includes a plurality of cam surfaces each cooperating with a different tube holding station and being adapted to receive a tube;

said spring means for mounting said tube holding means including a plurality of spring means for mounting said tube holding stations to said peristaltic pump;

each of said means for mounting including a cam surface spaced from said rollers by a guide surface connected to the cam surface;

a plurality of flexible tubes each having a different one of a corresponding plurality of flexible walls;

each of said tubes corresponding to a different cam surface means; and

each of said tube holding means including inlet and outlet tube holding means, spring means for biasing said inlet and outlet tube holding means against said rollers.

17. A peristaltic pump in accordance with claim 15 in which the spring means includes means for imparting two degrees of freedom to the tube holding means, which are up-down and side-to-side motion, and the pivoted hinge means impart a third degree of motion to the tube holding means, which is pivoting rotation about the hinge.

18. A peristaltic pump in accordance with claim 17 in which the hinge means imparts a fourth degree of motion to the tube holding means, which is sliding away and toward the hinge.

19. A peristaltic pump in accordance with claim 18 whereby the four degrees of freedom allow the guide surface to contact four rollers simultaneously.

20. A peristaltic pump in accordance with claim 17 whereby the three degrees of freedom allow the guide surface means to contact three rollers simultaneously.

21. A peristaltic pump in accordance with claim 20 in which said quide surfaces and a plurality of rollers have dimensions such that successive rollers contact at least one-eighth of the total lengths of guide surface whereby said tube is not completely compressed until just before it begins releasing the tube near said outlet end.

22. A peristaltic pump for pumping fluids through a plurality of tubes comprising:

a drive shaft;

a plurality of rollers mounted to said drive shaft for orbiting thereabout;

a plurality of tube holding means;

a plurality of cam surface means each having a corresponding cam surface;

each of such tube holding means having mounted to it a corresponding one of said cam surface means adapted to receive a corresponding tube of said plurality of tubes on a corresponding one of said cam surfaces;

a plurality of spring means for mounting said tube holding means with at least some of said tube holding means being movable with respect to others of said tube holding means while said peristaltic pump is operating to pump fluids, whereby said cam surfaces are independently self-adjusting;

a plurality of guide surface means each having a different one of a plurality of guide surfaces;

each of said cam surfaces being spaced from said rollers by a corresponding one of said guide surfaces incorporated in the tube holding means, whereby the amount each of said tubes of said plurality of tubes is squeezed by said rollers depends upon the distance between its corresponding guide surface and cam surface; and

said distance between corresponding guide surfaces and cam surfaces differing at different positions along the guide surfaces so as to provide a controlled sequence of degree of squeezing of the tubes by rollers based on the position of the rollers along corresponding guide surfaces.

23. A peristaltic pump according to claim 22 in which said tube holding means and spring means include cooperating release means wherein at least some of said tube holding means may be removed from said peristaltic pump while said peristaltic pump is operating to pump fluids through tubes in others of said tube holding means.

24. A peristaltic pump for pumping fluids through a plurality of tubes comprising:

a drive shaft;

a plurality of rollers mounted to said drive shaft for orbiting thereabout;

a plurality of tube holding means;

a plurality of cam surface means each having a corresponding cam surface;

each of said tube holding means having mounted to it a corresponding one of said cam surface means adapted to receive a corresponding tube of said plurality of tubes on a corresponding one of said cam surfaces;

a plurality of spring means for mounting said tube holding means;

a plurality of guide surface means each having a different one of a plurality of guide surfaces; and

each of said cam surfaces being spaced from said rollers by a corresponding one of said guide surfaces incorporated in the tube holding means, whereby the amount each of said tubes of said plurality of tubes is squeezed by said rollers depends upon the distance between its corresponding guide surface and cam surfaces;

said distance between corresponding guide surfaces and cam surfaces differing at different positions along the guides surface so as to provide a controlled sequence of degree of squeezing of the tubes by rollers based on the position of the rollers along corresponding guide surfaces;

each of said spring means;

including inlet and outlet spring biasing means for biasing said tube holding means toward said rollers; and

spring-biased pivotable hinge means for biasing said tube holding means away from said rollers;

said inlet and outlet spring biasing means including at least a first spring and said spring-biased pivotable hinge means including at least a second spring said first spring being stiffer than said second spring.

25. A peristaltic pump in accordance with claim 24 in which said guide surfaces and plurality of rollers have dimensions such that successive rollers contact at least one-eighth of the total length of said guide surfaces and less than three-quarters of the total length of the guide surface whereby said tube is not completely compressed until just before it begins releasing the tube near said outlet end.