SPIRAL-WOUND ELEMENTS

A spiral-wound element consists of several layers of flat-sheet membranes, spacers, and drainage fabrics (permeate carriers), which are rolled together into a spiral configuration (Fig. 1). At the center of the element is the permeate collection tube, which carries the collected permeate out through the end of the module housing. Sealing is achieved by means of an adapter equipped with O-rings.

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The active separation layer of the asymmetric semipermeable membrane is located on both sides of the spacer and is characterized by high mechanical strength and robustness.

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The spiral-wound element essentially consists of the membrane module housed within a pressure vessel.

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To prevent the individual membrane layers or spacers from telescoping due to the continuous cross-flow through the module, so-called ATDs (Anti-Telescoping Devices) are also installed in the housing.