Abstract: Pressure vessels having end closures for sealing at least one open end are constructed so as to provide full-bore access to a generally tubular shell portion wherein one or more filter cartridges will be disposed. A sealing ring (45) of rectangular cross section is seated in a groove provided in the tubular shell (15) at a location axially inward of a cylindrical surface region wherein a central annular groove is provided. A closure head (39) fits within this annular surface and includes a shoulder (73) which prevents insertion past the scaling ring (45).

Abstract: Methods for making tubular pressure vessels from polymer-impregnated fibrous material utilize cylindrical mandrels that are helically wound while rotating about a horizontal axis. After end closure fittings are installed on the mandrel, a barrier layer having a thickness of about 0.015 in is created by helically winding a strip of nonwoven polyester fiber material which is impregnated and coated with a mixture of two resin systems, one which is promptly cured by UV radiation while the other remains uncured. The resultant barrier layer is stable and drip-free and is inspected so minor defects can be remedied. A time lag of several hours before winding the major portion of the sidewall of the barrier layer subassembly is completely acceptable if an epoxy resin plus acid anhydride curing agent system is used having an extended pot-life of 12 to 15 hours.