Peristalic pump

Abstract

A peristaltic pump system including an arcuate pressing surface, a force element that applies an occluding force towards the pressing surface, a drive mechanism that drives the force element, a diaphragm disposed between the pressing surface and the force element that defines a pump cavity, an actuator strip disposed between the diaphragm and the force element that receives the occluding force, deflects to deform the diaphragm, and occludes the pump cavity, a support structure that retains the actuator and diaphragm positions relative to the pressing surface, and a restitution mechanism that recovers the open pump cavity configuration.

We claim: 
     
         1 . A peristaltic pump system comprising:
 a planetary rotor sub-system, including:
 a rotor; 
 a ring defining a pressing surface along the inner bearing surface, the pressing surface defining a groove along a circumferential section, wherein the groove has a substantially well-shaped cross section; and 
 a planetary roller element, driven by relative motion between the pressing surface and the rotor, wherein the roller element rolls along the pressing surface and applies an occluding force against the pressing surface; 
   an occlusion sub-system including:
 a diaphragm sheet that seals the groove opening, defining a deformable volume in conjunction with the groove, wherein the deformable volume is operable between:
 an open configuration, wherein the deformable volume is unoccluded; and 
 an occluded configuration, wherein the deformable volume is occluded; 
 
 an actuator strip, disposed between the roller element and the diaphragm, that biases the deformable volume to recover the open configuration, the actuator strip having a having a butte-shaped cross-sectional profile with a narrow occluding surface, a wide bearing surface, and radiused side walls, wherein the occluding surface is coupled to the diaphragm along the longitudinal centerline of the diaphragm, and the bearing surface couples to the roller element; and 
 a support structure including:
 a diaphragm restraint portion that clamps the diaphragm edges against the pressing surface of the ring; and 
 an actuator restraint portion, disposed along the longitudinal edges of the actuator bearing surface, that limits the deflection of the actuator away from the pressing surface; 
 
 wherein the actuator strip is held in tension against the actuator restraint portion to bias the deformable volume in an open configuration; 
   wherein the occlusion system is operable in three modes:
 a rest mode, wherein the deformable volume achieves the open configuration; 
 an occluded mode, wherein the rolling element applies an occluding force to a localized section of the bearing surface, deflecting the actuator strip such that the occluding surface deforms the diaphragm, occluding the corresponding section of the deformable volume; and 
 a pressurized mode, wherein the pressure within the deformable volume is higher than ambient pressure, wherein the actuator restraint portion prevents actuator deflection, preventing diaphragm expansion, maintaining the volume of the deformable volume and maintaining the pressure within the deformable volume.