Peristaltic pumps

Abstract

A peristaltic pump comprises a drivable rotor, having at least one pressing member, and a housing comprising a cylindrical stator in which the rotor is rotatable. Flexible tubing, having an inlet side and an outlet side, extends circumferentially around the cylindrical stator against an inner wall. The peristaltic pump includes a radially deformable ring positioned between the rotor and the circumferentially extending flexible tubing. The ring is deformed by the pressing member upon rotation of the rotor and this compresses the flexible tubing against the inner wall of the cylindrical stator to convey liquid along the flexible tubing. The radially deformable ring includes a ring anchor which prevents rotation of the radially deformable ring during rotation of the rotor. The ring anchor is engaged with the housing to secure the ring anchor to the housing whilst allowing reciprocal movement of the ring anchor in a radial direction.

1 . A peristaltic pump comprising:
 a drivable rotor having at least one pressing member;   a housing comprising a cylindrical stator in which the rotor is rotatable;   flexible tubing having an inlet side and an outlet side, the flexible tubing extending circumferentially around the stator against an inner wall;   a radially deformable ring positioned between the rotor and the circumferentially extending flexible tubing, the ring being deformable by the at least one pressing member upon rotation of the rotor to compress the flexible tubing against the inner wall of the cylindrical stator to thereby convey liquid along the flexible tubing;   wherein the inlet side and the outlet side of the flexible tubing are arranged side-by-side so that the flexible tubing extends in a substantially radial direction outwardly away from the cylindrical stator;   wherein the radially deformable ring includes a ring anchor projecting radially outwardly in a radial direction from the radially deformable ring and is located between the inlet side and the outlet side of the flexible tubing;   characterised in that:   the ring anchor is mounted to the housing to secure the ring anchor to the housing whilst allowing reciprocal movement of the ring anchor in the radial direction.   
     
     
         2 . A peristaltic pump according to  claim 1 , wherein the ring anchor has a housing engaging protrusion that is reciprocally mounted within a radially extending sub-housing formed as part of the housing. 
     
     
         3 . A peristaltic pump according to  claim 2 , wherein:
 the sub-housing comprises a slot extending in the radial direction; and   the housing engaging protrusion of the ring anchor is mounted through the slot to allow reciprocal movement of the ring anchor in the radial direction along a length of the slot.   
     
     
         4 . A peristaltic pump according to  claim 3 , wherein:
 the housing engaging protrusion of the ring anchor is elongated in the radial direction along a length of the slot such that a length of the housing engaging portion in the radial direction is at least 50% greater than a width of the slot.   
     
     
         5 . A peristaltic pump according to  claim 2 , wherein:
 the housing engaging protrusion of the ring anchor comprises a thickened mounting portion formed at a radially outer end of the ring anchor; and   the sub-housing comprises an opening at a radially inner end through which the ring anchor passes, the opening being narrower than the thickened mounting portion of the ring anchor to allow reciprocal movement of the thickened mounting portion of the ring anchor along a radial length of the sub-housing whilst maintaining the ring anchor within the sub-housing.   
     
     
         6 . A peristalic pump according to  claim 5 , wherein:
 the housing engaging protrusion of the ring anchor is elongated in the radial direction along radial length of the sub-housing such that a length of the housing engaging protrusion along the radial length is at least 50% greater than a width of the sub-housing.   
     
     
         7 . A peristaltic pump according to  claim 1 , wherein the housing has a ring anchor engaging protrusion that is reciprocally mounted within a radially extending sub-housing formed as part of the ring-anchor. 
     
     
         8 . A peristaltic pump according to  claim 7 , wherein:
 the ring anchor engaging protrusion of the housing comprises an axially extending finger;   the sub-housing of the ring anchor comprises a radially extending slot formed through the ring anchor; and   the axially extending finger is mounted within the slot.   
     
     
         9 . A peristaltic pump according to  claim 8 , wherein:
 the ring anchor engaging protrusion of the housing is elongated along a direction of the radially extending slot of the ring anchor such that a length of the ring anchor engaging protrusion along the direction of the radially extending slot is at least 50% greater than width of the radially extending slot.   
     
     
         10 . A peristaltic pump according to  claim 7 , wherein:
 the ring anchor engaging protrusion of the housing comprises an axially extending portion having a thickened mounting part at a radially inner end and a thinner part extending radially outwards from the thickened mounting part; and   the sub-housing of the ring anchor is formed at a radially outer end of the ring anchor and comprises a radially extending slot having an opening at a radially outer end, the thinner part of the ring anchor engaging protrusion extending through the opening, the opening being narrower than the thickened mounting part of the housing to allow reciprocal movement of the ring anchor along a radial length of the sub-housing whilst maintaining the ring anchor engaging protrusion within the sub-housing of the ring anchor.   
     
     
         11 . A peristaltic pump according to  claim 10 , wherein:
 the thickened mounting part of the ring anchor engaging protrusion is elongated along a direction of the radially extending slot of the ring anchor such that a length of the thickened mounting part along the direction of the radially extending slot is at least 50% greater than width of the radially extending slot.   
     
     
         12 . A peristaltic pump according to  claim 1 , wherein the radially deformable ring is formed of polyamide(nylon) (PA), polypropylene (PP), polyethylene (PE), polyoxymethylene(acetal) (POM), polyethylene terephthalate (PET), or a thermoplastic elastomer (TPE). 
     
     
         13 . A method for assembling a peristaltic pump according to  claim 1 , the method comprising:
 locating the flexible tubing circumferentially around the radially deformable ring and in contact therewith, with the inlet side and the outlet side of the flexible tubing arranged side-by-side on either side of the ring anchor;   positioning the flexible tubing and the radially deformable ring in the cylindrical stator with the flexible tubing arranged against the inner wall of the cylindrical stator;   securing the ring anchor to the housing such that reciprocal movement of the ring anchor in the radial direction is possible; and   fitting the rotor in the cylindrical stator by simultaneously rotating the rotor and pressing the rotor into the centre of the radially deformable ring.