Abstract: A method of making a cylindrical pressure vessel (11) with a large diameter port in its sidewall includes the step of providing a mandrel (23) of desired diameter and filament winding upon the same. After winding one overall innermost layer, an annular reinforcement belt (16) is helically wound atop a defined region using a band (60) of resin impregnated parallel strands (39) under tension. The annular belt (16) is then itself helically overwound with the resin impregnated parallel strands of filamentary material under tension to provide two complete outer layers. After curing and removal from the mandrel (23) at least one aperture (71) is cut in the sidewall within the reinforcement belt (16) and a side port fitting (75) is installed in the aperture (71).

Abstract: A tubular pressure vessel for cross-flow filtration having two centrally located side ports that penetrate the sidewall and communicate with a central chamber that divides the pressure vessel bore into two axially separated sections that each contain a plurality of cylindrical, cross-flow filtration cartridges. The pair of diametrically opposed, central side ports are provided through the use of a short length of tubing that provides structural stability to the overall pressure vessel arrangement. A feedstream may enter the pressure vessel centrally and flow in both axial directions, creating two permeate streams and two concentrate streams, the latter of which might exit through horizontal side ports located near each end of the pressure vessel. Interconnecting such tubular side port structures in adjacent pressure vessels in a vertical stack provides a load-bearing vertical column and allows a single feed line to supply multiple pressure vessels.