Vessel diaphragm and method

Abstract

An elastic thermoplastic diaphragm for use in a vessel having an inner surface. The vessel includes a liner that has an inner liner surface and first and second ends. A first endcap is secured to the liner first end and a second endcap to the liner second end. The diaphragm is secured to the inner vessel surface and seals along a peripheral edge to the vessel inner surface so as to define a volume inside the vessel. The diaphragm can flex, and thereby increase or decrease the volume.

1 . A vessel subassembly, comprising: 
 a thermoplastic cylindrical liner having an inwardly facing surface and first and second ends;    a first thermoplastic endcap, said first endcap having an inwardly facing surface, an outwardly facing surface, and an open end, said outwardly facing surface of said first endcap being secured to said liner first end at said open end thereof;    a second thermoplastic endcap, said second endcap having an inwardly facing surface, an outwardly facing surface, and an open end, said outwardly facing surface of said second endcap being secured to said liner second end at said open end thereof, said liner and said first and second endcaps cooperating to define an interior volume of said vessel subassembly; and    a thermoplastic diaphragm, said diaphragm having a first side and a second side and being sealed to the inwardly facing surface of one of said first and second endcaps at the open end thereof, said diaphragm further being spaced remotely from said liner inwardly facing surface, said diaphragm defining a diaphragm interior volume that is fluidly isolated from a remainder of an interior volume of said vessel, and wherein said diaphragm is operable to expand and collapse so as to increase or decrease said diaphragm interior volume and correspondingly decrease or increase said remaining interior volume of said vessel.    
   
   
       2 . The vessel subassembly as defined in  claim 1 , further comprising an annular ring having inner and outer sides and being disposed between said diaphragm and said inwardly facing surface of said one of said first and second endcaps at the open end thereof, said diaphragm being sealed to said inner side of said ring and said inwardly facing surface of said one of said first and second endcaps being sealed to said outer side of said ring.  
   
   
       3 . The vessel subassembly as defined in  claim 1 , wherein the diaphragm is formed from a thermoplastic elastomeric material selected from the group consisting of ethyl vinyl acetate, rubber, rubber blends, and polypropylene-rubber blends.  
   
   
       4 . A vessel subassembly, comprising: 
 a thermoplastic cylindrical liner having an inwardly facing surface and first and second ends;    a first thermoplastic endcap, said first endcap having an inwardly facing surface and an open end, said first endcap open end being secured to said liner first end;    a second thermoplastic endcap, said second endcap having an inwardly facing surface and an open end, said second endcap open end being secured to said liner second end, said liner and said first and second endcaps cooperating to define an interior volume of said vessel subassembly; and    a thermoplastic diaphragm, said diaphragm having a first side and a second side and being sealed directly to the inwardly facing surface of said liner at a location spaced remotely from each of said first and second endcaps so as to separate said interior volume into first and second chambers, said first chamber being defined by said first side of said diaphragm, said first endcap, and a first portion of said liner while said second chamber being defined by said second side of said diaphragm, said second endcap, and a second portion of said liner.    
   
   
       5 . A vessel subassembly, comprising: 
 a thermoplastic cylindrical liner having an inwardly facing surface and first and second ends;    a first thermoplastic endcap, said first endcap being generally dome shaped and having an inwardly facing surface, an outwardly facing surface, and an open end, said first endcap outwardly facing surface being secured to said liner first end at said open end of said first endcap;    a second thermoplastic endcap, said second endcap being generally dome shaped and having an inwardly facing surface, an outwardly facing surface, and an open end, said second endcap outwardly facing surface being secured to said liner second end at said open end of said second endcap, said liner and said first and second endcaps cooperating to define an interior volume of said vessel subassembly; and    a thermoplastic diaphragm, said diaphragm having a first side and a second side and a peripheral edge, and being sealed directly to said inwardly facing surface of said first endcap at a location spaced remotely from said liner so as to separate said interior volume into first and second chambers, said first chamber being defined by said first side of said diaphragm and said first endcap inwardly facing surface while said second chamber being defined by said second side of said diaphragm, said second endcap inwardly facing surface, and said liner inwardly facing surface.    
   
   
       6 . A vessel subassembly, comprising: 
 a thermoplastic cylindrical liner having an inwardly facing surface and first and second ends;    a first thermoplastic endcap, said first endcap having an inwardly facing surface and an open end, and being secured to said liner first end at said open end;    a second thermoplastic endcap, said second endcap having an inwardly facing surface and an open end, and being secured to said liner second end at said open end, said liner and said first and second endcaps cooperating to define an interior volume of said vessel subassembly; and    a thermoplastic diaphragm, said diaphragm including a first diaphragm portion and a second diaphragm portion, each of said diaphragm portions having a first side and a second side, said second diaphragm portion second side engaging the inner surface of one of said first and second endcaps in a face to face manner while said first diaphragm portion is sealed to the inwardly facing surface of one of said liner and said one of said first and second endcaps so as to separate said interior volume into first and second chambers, said first chamber being at least partially defined by said first side of said second diaphragm portion and said first side of said first diaphragm portion while said second chamber being at least partially defined by said second side of said first diaphragm portion, the inwardly facing surface of the liner, and the inwardly facing surface of the other of said first and second endcaps.    
   
   
       7 . The vessel subassembly as defined in  claim 4 , wherein said diaphragm includes a peripheral edge that is sealed to said inwardly facing surface of said liner.  
   
   
       8 . A vessel subassembly, comprising: 
 a thermoplastic cylindrical liner having first and second ends;    a first thermoplastic endcap secured to said liner first end;    a second thermoplastic endcap secured to said liner second end, said liner and said first and second endcaps cooperating to define an interior volume of said vessel subassembly; and    a thermoplastic diaphragm, said diaphragm serving to separate said interior volume into first and second chambers;    wherein said diaphragm includes a first diaphragm portion, a second diaphragm portion, and a ring, said first diaphragm portion and said second diaphragm portion being secured to one of said first and second endcaps, said ring being interposed between a peripheral edge of said first diaphragm portion and said inner surface of said one of said first and second endcaps, said ring being sealed to each of said first diaphragm portion peripheral edge and said inner surface of said one of said first and second endcaps, wherein said second diaphragm portion covers said inner surface of said one of said first and second endcaps and wherein said first diaphragm portion extends from said second diaphragm portion toward the other of said first and second endcaps.