The Dow Chemical Company

Keith R Denslow

Richard E Skochdopole

Damoder Reddy

The present invention relates to a spiral-wound membrane module having a semi-permeable membrane which has a central high pressure premeatae region flanked on opposite sides by two lower pressure edge portions. The edge portions facilitate the dispersion of and the collection of the feed fluid being treated and assist in obtaining a more uniform flow of the feed fluid through the high pressure region of the membrane. In one embodiment, the module has entrance and exit flow means for a counter-current flow of a sweep fluid through the permeate. Preferably, the high pressure permeate region is a high density porous spacer flanked on two sides with low density porous spacers. In one embodiment, the higher pressure permeate region and flanking low pressure drop permeate regions are obtained by specifically positioned lines of adhesive or glue spots (or lines) having a specific size and spacing. Generally the spots (or lines) are positioned in a generally axial configuration to the central pipe. Generally, the glue spots or lines are positioned in the permeate passageway in a pattern to obtain controlled flow of the countercurrent, cocurrent, or crosscurrent sweep fluid.

Spiral-wound membrane separation device with feed and permeate/sweep

Generally linear foamable strandular particles which are asymmetrical about a plane generally containing the longitudinal axis provide a desired curled dunnage material when heated to cause foaming. A wide variety of methods may be used to introduce the desired asymmetry.

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Midland, MI, United States of America

Keith R Denslow