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.

What is claimed is:  
     
         1 . A thermoplastic diaphragm for use in a vessel having an inner surface, said diaphragm comprises a peripheral edge, and is adapted to be sealed along said peripheral edge to said vessel inner surface so as to define a volume inside said vessel, said diaphragm is operable to expand and collapse so as to increase or decrease said volume.  
     
     
         2 . The diaphragm as defined in  claim 1 , wherein said diaphragm continuously seals along said peripheral edge so as to isolate, a first fluid portion from a second fluid portion.  
     
     
         3 . The diaphragm as defined in  claim 1 , further comprising an annular ring having inner and outer sides and being disposed between said peripheral edge and said vessel inner surface, said peripheral edge seals to said inner side of said ring and said vessel inner surface seals to said outer side of said ring, whereby said diaphragm is sealed to said vessel inner surface at said peripheral edge.  
     
     
         4 . The diaphragm as defined in  claim 1 , wherein the diaphragm is formed from a thermoplastic elastomeric material.  
     
     
         5 . The diaphragm as defined in  claim 4 , wherein the thermoplastic elastomeric material is selected from the group consisting of ethyl vinyl acetate, rubber, rubber blends, and polypropylene-rubber blends.  
     
     
         6 . A vessel subassembly, comprising: 
 a thermoplastic cylindrical liner having a 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 being sealed an inner surface of one of said liner and said first and second endcaps so as to separate said interior volume into first and second chambers.    
     
     
         7 . The vessel as defined in  claim 6 , wherein said diaphragm includes a peripheral edge, and said diaphragm is sealed along said peripheral edge to said endcap inner surface.  
     
     
         8 . The vessel as defined in  claim 6 , wherein said diaphragm includes a first diaphragm portion and a second diaphragm portion, said second diaphragm covering said second endcap inner surface.  
     
     
         9 . The vessel as defined in  claim 6 , wherein said diaphragm includes a peripheral edge that is sealed to an inner surface of said liner.  
     
     
         10 . A method of assembling a vessel having an inner surface, comprising the steps of: 
 providing a liner having first and second ends and an inner surface defining a portion of said vessel inner surface;    securing a diaphragm to an inner surface of said vessel; and    securing a first endcap to said liner first end and a second endcap to said liner second end, each of said first and second endcaps having an inner surface defining a portion of said vessel inner surface.    
     
     
         11 . The method as defined in  claim 10 , further comprising the step of securing said diaphragm directly to the inner surface of one of said first or second endcaps.  
     
     
         12 . The method as defined in  claim 10 , further comprising the step of securing said diaphragm directly to said liner inner surface.  
     
     
         13 . The method as defined in  claim 10 , wherein said diaphragm comprises a ring, and wherein said diaphragm securing step includes the steps of securing said diaphragm to said ring, and securing said ring to said vessel inner surface.  
     
     
         14 . The method as defined in  claim 13 , further comprising the steps of disposing an assembly seam between said endcaps and said liner, and securing said ring to said liner inner surface at a location spaced from said assembly seam.  
     
     
         15 . The method as defined in  claim 10 , wherein one of said securing steps includes adhesive sealing, heat sealing, hot plate welding, laser welding, vibrational welding, or spin welding.  
     
     
         16 . A vessel, comprising: 
 a cylindrical liner having an end and defining an axis;    an endcap attached to the liner end and comprising a ring-shaped seat, the seat defining a seat aperture through the endcap, and the seat having a portion extending radially outward and defining a ring-shaped first groove, the first groove having an open end facing axially in toward the vessel;    a thermoplastic diaphragm comprising a sealing ring defining a ring aperture; and    a fitting assembly comprising a fitting, the fitting extending through the ring aperture and the seat aperture, and the fitting having a portion extending radially outward and defining a ring-shaped second groove, the second groove having an open end facing axially out away the vessel, the first and the second ring-shaped grooves cooperating with each other to define an annular recess, the ring being disposed in the annular recess, and thereby sealing the diaphragm to the fitting assembly and the ring-shaped seat.    
     
     
         17 . The vessel as defined in  claim 16 , wherein the fitting further defines a C-ring groove disposed outside of the vessel, and the fitting assembly further comprising a C-ring disposed in the C-ring groove, thereby temporarily securing the fitting to the endcap.  
     
     
         18 . The vessel as defined in  claim 16 , wherein the fitting assembly further comprises a threaded outer cap, and the fitting has a threaded end threadedly connected to the threaded outer cap.  
     
     
         19 . The vessel as defined in  claim 16 , wherein the diaphragm is a first one of a plurality of diaphragms and further comprising a second diaphragm and a rib, the first and second diaphragms having free ends in continuous engagement with each other to define a seam, the rib clamping the first and second diaphragms together at the free ends, and thereby sealing the first and second diaphragms to each other at the seam.  
     
     
         20 . The-Vessel as defined in  claim 16 , wherein the diaphragm is a first one of a plurality of diaphragms and further comprising a second diaphragm, said first and second diaphragms having free ends in continuous engagement and welded to one another and thereby sealing the first and second diaphragms to each other at the seam.  
     
     
         21 . The vessel as defined in  claim 16 , wherein the endcap is a first one of a plurality of endcaps and further comprising a second endcap attached to a liner end opposite the first endcap, the second endcap comprising a ring-shaped seat with a raised portion, the raised portion defining a valve aperture, and the vessel further comprising a valve extending through the valve aperture that is seated in the raised portion and sealed to the second endcap.  
     
     
         22 . A thermoplastic diaphragm assembly, comprising: 
 a first diaphragm portion, said first diaphragm portion being generally bowl shaped and defining an open end and an inlet opening;    a second diaphragm portion, said second diaphragm portion being generally bowl shaped and having an open end, said first diaphragm portion open end being secured to said second diaphragm portion open end, and,    a fitting secured to an outer surface of said first diaphragm portion at said inlet opening.    
     
     
         23 . The assembly according to  claim 22 , wherein at least one of said first and second diaphragm portions is formed from a thermoplastic elastomer material.  
     
     
         24 . The assembly according to  claim 22 , wherein said first diaphragm portion is relatively less flexible than said second diaphragm portion.  
     
     
         25 . The assembly according to  claim 22 , wherein said first diaphragm portion includes a screen that overlies said fitting.  
     
     
         26 . The assembly according to  claim 25 , wherein said screen is integrally formed with said first diaphragm portion.