Spiral wound separation device and method of making same

• Main Author: HOPKINS; DAVID H
• Format: Patent
• Language: English
• Published: 30.11.1993
• Edition: 5
• Subjects: PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; TRANSPORTING

A sandwich of a permeate fabric material within a folded sheet of semipermeable membrane is spirally wound together with a sheet of porous feed pathway material about a mandrel which, upon its removal, provides a central hollow region in the wound element. A single band of adhesive seals the outer end of the envelope, and once wrapping is completed, a thin layer of porous tape holds the winding tight. A porous small diameter tube is inserted into a pocket adjacent the fold in the semipermeable membrane material near the center of the winding and serves as a permeate discharge conduit. Axial ends of the spirally wound subassembly are sequentially potted in resin to complete the basic fabrication of the element. Communication with the feed pathway material is provided by drilling through the resin into the center hollow region. The spirally wound element can be used as a replacement cartridge for a device having a permanent housing, or it can be integrally bonded within a surrounding pressure vessel assembly to form a disposable water purification unit. Feedwater supplied to the open center region flows spirally outward, while permeating purified water flows spirally inward to the porous tube which serves as a pure water discharge conduit.