Abstract: The present disclosure provides a novel spiral wound membrane leaf packet with a unique substantially non-permeable polymeric resin folding area that has desirable physical and chemical resistance to strong cleaning conditions in industrial filtration applications including food or dairy processing, and the method to make and use the spiral wound membrane leaf packet, and a membrane filtration module that include the novel spiral wound membrane leaf packet.

Abstract: The subject of the present invention is an improved leaf packet useful in forming a spiral filtration module, the improved module which results from utilization of the leaf packet and a method of preparing the leaf packet. The membrane sheet utilized in forming a spiral filtration module is fused and densified in the area of its fold to increase the sheet density in this area and thus provide protection against mechanical failure. The densification includes the application of heat and pressure to the membrane surface of the sheet so as to densify the membrane surface and seal it against the penetration of feed stream liquid while also densifying the membrane, the backing and an optional reinforcing strip (if utilized).

Abstract: An ultrafiltration module and method of constructing same is the subject of the present invention. The module comprises a permeate collector tube and one or more membrane leaves wound around the tube together with a feed channel spacer so as to present spaced layers of membrane leaves or envelopes that are contacted by fluid flowing axially through the module in the channel provided by the feed spacer screen. The feed spacer screen projects beyond the terminal ends of the leaves to present an open mesh outerwrap screen circumscribing the wound leaves. A plurality of restraining bands are provided in longitudinally spaced relationship along the length of the module. These bands are designed to hold the entire module assembly in tight spiral relationship. Preferably, the bands are constructed of heat shrinkable material and are thus secured in place and tightened by the application of heat.