Partially preloaded pump diaphragms

Abstract

A partially preloaded diaphragm having an outer attachment portion defining a first plane (P) and disposed about an axis substantially perpendicular to the first plane. An inner attachment portion is disposed substantially perpendicular to the axis of the outer attachment portion and defines a second plane (C). The inner attachment portion is movable away from the outer attachment portion into a fully extended pumping position defining a third plane (F). The first plane and the second plane are spaced at a distance to define a preload distance (PC) when the diaphragm is at rest, and the first and third plane are spaced to define a pump stroke distance (PF) when the diaphragm is fully extended. The preload distance is from about 25 percent to about 85 percent of the pump stroke distance.

Having described the invention, what is claimed is:  
     
         1 . A partially preloaded diaphragm, comprising: 
 an outer attachment portion defining a first plane (P) and disposed about an axis substantially perpendicular to said first plane, and    an inner attachment portion disposed substantially perpendicular to said axis of said outer attachment portion and defining a second plane (C), said inner attachment portion being movable away from said outer attachment portion into a fully extended pumping position defining a third plane (F),    said first plane and said second plane being spaced at a distance to define a preload distance (PC) when said diaphragm is at rest, and said first and third plane being spaced to define a pump stroke distance (PF) when said diaphragm is fully extended,    said preload distance being from about 25 percent to about 85 percent of said pump stroke distance.    
     
     
         2 . The partially preloaded diaphragm according to  claim 1 , wherein said preload distance being from about 50 percent to about 75 percent of said pump stroke distance.  
     
     
         3 . The partially preloaded diaphragm according to  claim 2 , wherein said preload distance being about 50 percent of said pump stroke distance.  
     
     
         4 . The partially preloaded diaphragm according to  claim 2 , wherein said preload distance being about 67 percent of said pump stroke distance.  
     
     
         5 . The partially preloaded diaphragm according to  claim 1 , wherein said outer and inner attachment portions are adapted for attachment to a pump and further comprise an annular working portion connecting said outer and inner attachment portions.  
     
     
         6 . The partially preloaded diaphragm according to  claim 5 , further comprising a peripheral portion formed annularly between said inner attachment portion and said annular working portion when said inner attachment portion is moved into a fully extended pumping position.  
     
     
         7 . The partially preloaded diaphragm according to  claim 1 , wherein said diaphragm comprises a thermoplastic elastomer.  
     
     
         8 . The partially preloaded diaphragm according to  claim 1 , wherein said diaphragm comprises a thermoplastic elastomer selected from the group consisting of an EPDM rubber and polypropylene blend and a thermoplastic urethane.  
     
     
         9 . The partially preloaded diaphragm according to  claim 1 , wherein said diaphragm comprises a thermoplastic elastomer selected from the group consisting of SANTOPRENE, ESTANE, HYLENE, HYTREL, GEOLAST, SARLINK elastomers, and combinations thereof.  
     
     
         10 . The partially preloaded diaphragm according to  claim 1 , wherein said diaphragm comprises a fluoropolymer.  
     
     
         11 . The partially preloaded diaphragm according to  claim 10 , wherein said fluoropolymer is polytetrafluoroethylene.  
     
     
         12 . The partially preloaded diaphragm according to  claim 1 , wherein said outer attachment portion comprises a bead.  
     
     
         13 . The partially preloaded diaphragm according to  claim 1 , wherein said outer attachment portion comprises a dovetailed portion.  
     
     
         14 . The partially preloaded diaphragm according to  claim 1 , wherein said outer attachment portion comprises a plurality of holes for receiving fastening members.