Method and article for restraining extrusion of feed spacers and circumferential expansion in spiral filtration modules.

摘要

An ultrafiltration module (10) and method of constructing same is the subject of the present invention. The module (10) comprises a permeate collector tube (12) and one or more membrane leaves (16) wound around the tube (12) together with a feed channel spacer (18) so as to present spaced layers of membrane leaves or envelopes that are contacted by fluid flowing axially through the module (10) in the channel provided by the feed spacer screen (18). The feed spacer screen (18) projects beyond the terminal ends of the leaves (16) to present an open mesh outerwrap screen (20) circumscribing the wound leaves (16). A plurality of restraining bands (22) are provided in longitudinally spaced relationship along the length of the module (10). These bands (22) are designed to hold the entire module assembly (10) in tight spiral relationship. Preferably, the bands (22) are constructed of heat shrinkable material and are thus secured in place and tightened by the application of heat. After the restraining bands (22) are in place, a bypass screen (24) also of open mesh configuration is wrapped around the outerwrap (20) and the restraining bands (22) and secured by overlapping it onto itself and fusing the overlapped portion. <IMAGE> <IMAGE>