Peristaltic pump

Abstract

A peristaltic pump uses a length of elastic tube with an inlet at one end and an outlet at the second end for delivering fluid material an outlet pressure greater than the inlet pressure. A support element disposed along the length of elastic tube is in contact with the elastic tube. A mechanism moves a compression element into engagement with a segment of the elastic tube thereby forming a compressed segment with a tube center section and two folded tube edges wherein at least one surface engaging the folded tube edges has a contours that reduce stresses in the elastic tube walls at the folded tube edges increasing pump performance and/or life of the elastic tube.

1 . A perisaltic pump comprising:
 a length of elastic tube having tube walls, an inlet at a first end of the elastic tube for receiving a fluid material at a first pressure, and an outlet at a second end of the elastic tube for delivering the fluid material at a second pressure;   a support element disposed along and contacting the length of elastic tube; and   a mechanism for moving a compression element into engagement with a segment of the elastic tube thereby compressing the elastic tube and forming a compressed segment with a flattened tube center section and two folded tube edges, wherein at least one surface of the support element or the compression element, proximate to the folded tube edges, has contours that reduce stresses in the tube walls at the folded tube edges.   
   
   
       2 . The pump of  claim 1 , wherein the mechanism moves the compression element along the elastic tube thereby moving the compressed segment from a point proximate to a first end of the segment of the elastic tube to a point proximate to a second end of the segment of the elastic tube such that the compressed segment acts to move the fluid material from the inlet to the outlet of the elastic tube. 
   
   
       3 . The pump of  claim 1 , wherein the compression element is a roller that is free to rotate about its axial center and the mechanism rotates the roller on a radial arm in a plane substantially orthogonal to a surface of the support element. 
   
   
       4 . The pump of  claim 3 , wherein the roller is cylindrical in shape between opposing ends and has two end sections each having an edge surface at a first diameter and a center section with a center surface at a second diameter disposed over a width dimension between the two end sections, wherein the first diameter is smaller than the second diameter. 
   
   
       5 . The pump of  claim 4 , wherein the surface of the support element corresponding to the width dimension of the roller is substantially flat. 
   
   
       6 . The pump of  claim 3 , wherein the roller is cylindrical in shape between opposing ends with a surface at a diameter over a first width dimension and the support element has two end sections each with an edge surface at a first level and a center section disposed between the two end sections and having a center surface raised to a second level above the first level of the edge surfaces over a second width dimension smaller than the first width dimension. 
   
   
       7 . The pump of  claim 4 , wherein the support element has two end sections each with an edge surface substantially mirroring corresponding edge surfaces of the roller and a center section disposed between the two end sections and having a center surface substantially conforming to the center surface of the roller. 
   
   
       8 . The pump of  claim 1 , wherein the contours engaging the folded tube edges operates to prevent the elastic tube from translating orthogonal to the length dimension of the elastic tube when the elastic tube is compressed to pump a fluid. 
   
   
       9 . The pump of  claim 3 , wherein the roller is one of a plurality of rollers that the mechanism rotates into engagement with the elastic tube. 
   
   
       10 . The pump of  claim 1 , wherein the contours are configured to increase a useful lifetime of the elastic tube when used to transport fluid. 
   
   
       11 . The pump of  claim 1 , wherein the contours are adapted in part in response to a durometer value and/or the wall thickness of a material forming the elastic tube. 
   
   
       12 . The pump of  claim 1 , wherein the contours are formed by a smooth transition between levels of two surfaces. 
   
   
       13 . A peristaltic pump comprising:
 a length of elastic tube having tube walls, an inlet at a first end of the elastic tube for receiving a fluid material at a first pressure, and an outlet at a second end of the elastic tube for delivering the fluid material at a second pressure;   a support element disposed along and contacting the length of elastic tube; and   a mechanism for moving a compression element into engagement with a segment of the length of elastic tube thereby forming a compressed tube center section and two folded tube edges within the segment, wherein at least one surface of the support element surface or the compression element proximate to the folded tube edges has contours that operate to shape the folded tube edges to more fully and/or uniformly occlude the elastic tube and strengthen a seal made by the occlusion in the elastic tube thereby increasing a pressure and/or a vacuum produced by the peristaltic pump.   
   
   
       14 . The pump of  claim 13 , wherein the mechanism moves the compression element along the elastic tube thereby moving the compressed segment from a point proximate to a first end of the segment of the elastic tube to a point proximate to a second end of the segment of the elastic tube such that the compressed segment acts to move the fluid material from the inlet to the outlet of the elastic tube. 
   
   
       15 . The pump of  claim 13 , wherein the compression element is a roller that is free to rotate about its axial center and the mechanism rotates the roller on a radial arm in a plane substantially orthogonal to a surface of the support element. 
   
   
       16 . The pump of  claim 15 , wherein the roller is cylindrical in shape between opposing ends and has two end sections each having an edge surface at a first diameter and a center section with a center surface at a second diameter disposed over a width dimension between the two end sections, wherein the first diameter is smaller than the second diameter. 
   
   
       17 . The pump of  claim 16 , wherein the surface of the support element corresponding to the width dimension of the roller is substantially flat. 
   
   
       18 . The pump of  claim 15 , wherein the roller is cylindrical in shape between opposing ends with a surface at a diameter over a first width dimension; and the support element has two end sections each with a edge surface at a first level and a center section disposed between the two end sections; and having a center surface raised to a second level above the first level of the edge surfaces over a second width dimension smaller than the first width dimension. 
   
   
       19 . The pump of  claim 16 , wherein the support element has two end sections each with an edge surface substantially mirroring corresponding edge surfaces of the roller and a center section disposed between the two end sections and having a center surface substantially conforming to the center surface of the roller. 
   
   
       20 . The pump of  claim 13 , wherein the contours are formed by a smooth transition between levels of two surfaces. 
   
   
       21 . The pump of  claim 15 , wherein the roller is one of a plurality of rollers that the mechanism rotates into engagement with the elastic tube. 
   
   
       22 . The pump of  claim 13 , wherein the contours engaging the folded tube edges operates to prevent the elastic tube from translating orthogonal to the length dimension of the elastic tube when the elastic tube is compressed to pump a fluid. 
   
   
       23 . The pump of  claim 13 , wherein the contours are configured to increase a useful lifetime of the elastic tube when used to transport fluid. 
   
   
       24 . The pump of  claim 13 , wherein the contours are adapted in part in response to a durometer value and/or the wall thickness of a material forming the elastic tube.