Polymeric liner based gas cylinder with reduced permeability

Abstract

Disclosed are gas cylinder assemblies for containing pressurized gas. The gas cylinder assembly has a polymeric liner and a low-permeability barrier layer. The polymeric liner a first end portion, a second end portion and a central body. The central body comprises an outer surface and an inner surface disposed between the first end and the second end. The gas cylinder assembly comprises a reinforcement structure wound over the central body. The gas cylinder assembly further comprises a metal foil interposed between the reinforcement structure and central body. The metal foil is configured to reduce permeation of contents of the polymeric liner.

What is claimed is: 
     
         1 . A gas cylinder for containing pressurized gas, comprising:
 an internal pressure enclosure comprising:
 a first end portion; 
 a second end portion; and 
 a central body having a first end coupled with the first end portion and a second end coupled with the second end portion, the central body further having an outer surface and an inner surface disposed between the first end and the second end; 
 the first end portion, the second end portion, and the central body forming an enclosed cavity for storing pressurized gas wherein the inner surface of the central body forms at least a portion of an innermost surface of the internal pressure enclosure; 
 the central body between the inner surface and the outer surface being a continuous expanse of a homogenous material; 
   a reinforcement structure disposed over the central body; and   a metal foil interposed between the reinforcement structure and central body, the metal foil configured to reduce permeation of contents of the internal pressure enclosure.   
     
     
         2 . The gas cylinder of  claim 1 , wherein the metal foil is an aluminum foil having a thickness in a range between 0.0005 in and 0.05 inches. 
     
     
         3 . The gas cylinder of  claim 1 , further comprising an adhesive layer interposed between the metal foil and the central body. 
     
     
         4 . The gas cylinder of  claim 1 , wherein the metal foil comprises a portion of a metal foil structure comprising a polymer layer, the polymer layer of the metal foil structure disposed on a side of the metal foil such that the polymer layer is interposed between the metal foil and the central body. 
     
     
         5 . The gas cylinder of  claim 1 , wherein the central body comprises a cylindrical body and the first end portion comprises a hemispherical member coupled with one end of the cylindrical body, wherein the metal foil is disposed over the cylindrical body. 
     
     
         6 . The gas cylinder of  claim 1 , wherein the central body comprises a cylindrical body and the first end portion comprises a hemispherical member coupled with one end of the cylindrical body, wherein the metal foil has a circumferential end spaced apart from the hemispherical member. 
     
     
         7 . The gas cylinder of  claim 1 , wherein the metal foil is disposed in a laminate structure and is wound about the central body. 
     
     
         8 . The gas cylinder of  claim 7 , wherein the metal foil is wound circumferentially about the central body. 
     
     
         9 . A pressure vessel assembly, comprising:
 an internal polymeric liner comprising a central portion and a dome end portion on each end of the central portion, the central portion having an inner surface, an outer surface and a wall disposed between the inner surface and the outer surface;   a permeation barrier layer disposed over the central portion and on the dome end portions on one or more ends of the central portion;   a reinforcing layer comprising flexible ribbon material disposed over the permeation barrier.   
     
     
         10 . The pressure vessel assembly of  claim 9 , wherein the permeation barrier layer comprises a metal layer disposed over the outer surface of the central portion and on an outer surface of each of the dome end portions. 
     
     
         11 . The pressure vessel assembly of  claim 9 , wherein the permeation barrier layer comprises a metal film with overlapping longitudinal edges disposed over the outer surface of the central portion and on an outer surface of each of the dome end portions. 
     
     
         12 . The pressure vessel assembly of  claim 9 , wherein the permeation barrier layer comprises a polymeric layer comprising EVOH disposed over the outer surface of the central portion and on an outer surface of each of the dome end portions. 
     
     
         13 . The pressure vessel assembly of  claim 9 , wherein the permeation barrier layer comprises a first configuration disposed over the central portion and a second configuration disposed over an outer surface of each of the dome end portions, the second configuration different from the first configuration. 
     
     
         14 . The pressure vessel assembly of  claim 9 , wherein the permeation barrier layer comprises an elongate strip disposed over the central portion of the internal polymeric liner. 
     
     
         15 . The pressure vessel assembly of  claim 9 , wherein the permeation barrier layer comprises a plurality of elongate strips contacting an exterior surface of the internal polymeric liner. 
     
     
         16 . A method of producing a gas cylinder for containing pressurized gas, the method comprising:
 providing a polymeric cylinder extending between a first end and a second end, the polymeric cylinder comprising an inner circumferential surface and an outer circumferential surface, the inner circumferential surface providing at least a portion of an innermost surface of the gas cylinder;   forming a permeation barrier layer over the outer circumferential surface, the permeation barrier layer having a thickness greater than 0.0002 in;   providing a first dome-shaped member having a first opening and a second dome-shape member having a second opening;   securing the first dome-shape member to the first end of the polymeric cylinder and securing the second dome-shape member to the second end to obtain a low permeation vessel having a central portion having an outer surface defined by the permeation barrier layer;   winding one or more strips of a reinforcing member over the permeation barrier layer to form an outer shell of the gas cylinder.   
     
     
         17 . The method of  claim 16 , wherein forming the permeation barrier layer comprises wrapping one or more metal foils over the outer circumferential surface, wherein the metal foil has a thickness in a range between 0.0005 in to 0.05 in. 
     
     
         18 . The method of  claim 16 , wherein forming the permeation barrier layer comprises depositing a metallic layer by a vapor deposition process. 
     
     
         19 . The method of  claim 16 , wherein forming the permeation barrier layer applying strips of a metal coated film longitudinally over the outer surface of the polymeric cylinder. 
     
     
         20 . The method of  claim 16 , wherein the permeation barrier layer is referred as a first permeation barrier layer, wherein the method further comprises disposing a second permeation barrier layer on the first dome portion and/or the second dome portion, wherein the first permeation barrier layer and the second permeation barrier layer have different configurations.