Segmented Peristaltic Pump Chamber

A miniature peristaltic pump is described in Diabetic Care, Volume 3, No. 2 of March-April, 1980. This publication was prior to the application for process U.S. Pat. No. 4,452,599 of Albissor et alia. The work of Albissor concentrated on the concept of a double tube system. The chamber of such a pump holds the tubing and the rotor and is contained inside a cover which constitutes the stator. The eccentric rotor squeezes the resilient tubing which is in a single loop inside the circular stator, and thereby pushes the liquid in the tubing from an inlet port to an outlet port. The major use for peristaltic pumps is Biomedical. Ideally, a pump chamber should be assembled and ready for insertion by connecting the external inlet and outlet ports to tubing running from the source of medication to the sink for medication. However, the structure of the stator and the eccentricity of the rotor results in a pinched resilient tube inside the chamber. Not only can this pinch result in a permanent occlusion, but it prevents gravity flushing of air bubbles from the system. If one removes a chord from the arc of the stator, it will leave the resilient tubing free from becoming pinched at a set position of the rotor, so the tubing remains an open channel. By inserting the arc, the stator is complete and the liquid may be pumped.

The major portion of the structure of a peristaltic pump is in the rotational drive means or motor. This application describes an improvement on the small peristaltic pumps used in medical applications by the introduction of a head system separate from the motor which can be preloaded with tubing and stored for future and rapid use. It also permits the tubing to be loaded with medicament by gravity flow while inserted in the head because of the unoccluded passage if the cap is not attached.

A segmented stator for a peristaltic pump is described. By removing a segment of the periphery of a stator, an open area is created where the resilient tubing used by a peristaltic pump would not be compressed, avoiding occlusion and facilitating the flushing of air.

FIG. 1 is a drawing of a blow-up of a peristaltic head with a segmented stator.

A Peristaltic pump head comprises a front segmented stator (1), a rotor (2), a loop of resilient tubing (3), and a rear segmented stator (4), and a cap (5). The rear segmented stator (4) has an inner surface, which is an arc (14). The cap (5) also has an inner surface along the radius which is a chord (15). The space between these inner surfaces (14 and 15) and rotor form a tubing track into which the resilient tubing (3) is placed. The resilient tubing (3) is connected to the internal inlet port (6) and internal outlet port (7) in such a manner to loop around the rotor (2). When the rotor marker (8) is aligned with the stator marker (9), the eccentricity of the rotor displaces the resilient tubing into the missing segment of the stator. Mating surfaces engage each other on the front and rear segments of that stator and lock, forming an assembled head. As long as the rotor and stator markers (8 and 9) are aligned, the resilient tubing is not pinched. The external ports (11) may be attached to tubing to create a hydraulic circuit. Air may be flushed from the circuit by either flowing liquid through the system, or holding the circuit vertically to permit the air bubbles to rise. The cap (5) may be snapped onto the chamber which will compress the resilient tube (3). A shaft (12) from a motor engages the rotor on the extremity (13) and causes the rotor (2) to turn, squeezing liquid through the resilient tube (3) conveying said liquid from the inlet port to the outlet port. The fully assembled head may be mated and rigidly attached to a motor shaft creating a pump.