Peristaltic pumps

• US 4,496,295 A
• Filed: 03/20/1984
• Issued: 01/29/1985
• Est. Priority Date: 03/22/1982
• Status: Expired due to Fees

• Current Assignee: Blue-White Industries Ltd
• Original Assignee: Blue-White Industries Ltd
• Inventors: King, Oswald M.
• Primary Examiner(s): Gluck, Richard E.
• Application Number:
  US06/591,430
• Time in Patent Office: 315 Days
• Field of Search: 417/474-477, 138/118, 138/DIG. 5, 138/DIG. 8
• US Class Current: 417/477.12
• CPC Class Codes: F04B 43/1253 by using two or more rollers as squeezing elements, the rollers moving on an arc of a circle during squeezing

Abstract

An improved peristaltic pump employs a pump tube which is pre-stressed by being twisted in the direction of the length of the tube about its axis.

Claims

1. For use in a peristaltic pump of the kind in which a length of tubing is disposed in a housing, the housing having an end wall and having an inner wall whose shape defines a segment of a circle, and a set of rollers rotatable about an axis which extends through the end wall, said rollers serving to compress said tubing against said side wall at successive points along said side wall, and the housing being formed with locking elements for engaging key structures at the ends of the tubing and preventing relative rotation of the tubing ends about the central axis of the tubing from a given angular orientation of said key structures:

a length of resilient peristaltic pump tubing each end of which is fitted with a respectively associated key structure fixed to the tubing such that when the tubing is relaxed the two key structures have a relative angular orientation about the center line of the tubing which differs from said given angular orientation by a substantial amount not more than one-half turn about said central axis.

2. The invention defined in claim 1 in which said tubing will lie in a substantially flat plane when relaxed.

3. The invention defined in claim 1 in which said key structures are fixed to the ends of said tubing and said relative angular displacement about the center line of the tubing is between one-tenth and one-half of a turn about the central axis of the tubing.

4. For use in a peristaltic pump housing of the kind which has a length of perstaltic tubing disposed in a cavity formed by a rear wall and side walls which side walls form a segment of a circle and against which side walls the tubing pressed by a set of pump rollers, the pump housing including locking means for holding the tubing ends against relative rotation about the central axis of the tubing, in combination:

a length of resilient tubing; and

means in the form of end fittings each fixed to a respectively associated end of said length of tubing for cooperation with said locking means of the pump housing for holding said tube twisted about its axial center line such that the central region of the tubing is biased toward said rear wall of the pump when installed.

5. The invention defined in claim 4 in which said end fittings are formed as rotation preventing keys and in which the keys are displaced rotationally relative to the central axis of the tubing by an amount less than one-half turn and more than one-tenth turn.

6. A peristaltic pump comprising:

a pump body which defines a cavity having a rear wall and a side wall which side wall forms a segment of a circle;

a length of resilient tubing disposed in said body such that a central region of the tubing lies against said side wall;

means mounted for rotation in said cavity for pressing the tubing against the pump body at successive points along said side wall; and

means for holding said tubing twisted about its central axis in a degree less than one-half turn and more than one-tenth turn such that a central region of the tubing is biased toward said rear wall.

7. The invention defined in claim 6 in which said means for holding said tubing comprises complementally formed lock and key structures carried on the pump body and on the ends of the length of tubing such that a lock and a key is associated with each end of said length of tubing.

8. In a peristaltic pump of the kind in which fluid is forced through a resilient tube which is squeezed at successive points along is length between an inner circular wall of a cylindrical cavity and a cam carried on a holder which is rotatable on the axis of the circular wall, the improvement which comprises fixing the ends of the resilient tube relative to the cavity wall such that the tube is held twisted about its longitudinal center line less than one-half turn and more than one-tenth turn.

9. The invention defined in claim 8 in which the cam is driven from one side of said cavity and in which said tube is twisted by a relative rotation of portions of said tube whereby the central region of the tube is biased toward said one side of said cavity.

10. The invention defined in claim 9 which further comprises a structure in which the ends of said tube are held fixed;

and

said structure and the ends of said tube having conformations that are complementary when said tube is so twisted and which prevent untwisting of said tube.