GB1296205A - - Google Patents

Abstract

1296205 Porous tubular or plate like laminates LANGLEY LONDON Ltd 9 Dec 1968 [9 Dec 1968] 58423/68 Heading B5N [Also in Division F2] A porous tubular or plate-like element is made from two or more layers of resin bonded vegetable, mineral or synthetic plastics fibres bonded together by a cured resin, one layer being a mat of irregularly arranged fibres 2 and another of woven fibres 1 and a water permeable membrane. As shown the layer 2 is placed on the layer 1, impregnated in a bath 5 containing a resin/solvent mixture, excess mixture is drained off at point 6, the solvent evaporated off in an oven 8, the strip cut into sheets, wrapped about a mandrel 10 to produce tube 12, heat shrinkable film 11 is placed about the tube 12, the impregnating resin cured in oven 13 and the mandrel removed after curing is complete prior to the tube 12 being ground to the required dimensions. Preferred materials of construction are glass-fibre and polyester or epoxy resin. The amount of resin left after drying in the oven 8 should be 30-35% of the total weight, a higher content reducing the elements porosity but increasing its mechanical strength and vice versa. The membrane is applied to the element, the irregular fibrous layer 2 being adjacent to it. A permeable membrane support may be on either surface of the element and in one embodiment is a filter placed on to the sheet prior to winding on the mandrel 10 so as to line the bore of the tube 12. In a modification the porous tube may be produced from a spirally wound, woven, fibrous tape and/or bundles of fibres applied by filamentary or wave form winding. Tubes having more than two layers, Fig. 1, 2, 3 (not shown) may be produced by cutting longer sheets and winding them as shown.