GB686314A - Improvements in or relating to pressure-sensitive devices incorporating flexible diaphragms - Google Patents

Abstract

686,314. Coated fabrics; compound fabrics. ROLLS-ROYCE, Ltd. Nov. 9, 1950. [Nov. 9, 1949] No. 28770/49. Class 140. A pressure-sensitive device such as those described in Specifications 679,011 and 679,012, [both in Group XXIX], incorporates a flexible diaphragm to be subjected to the pressure drop to which the device is sensitive, which diaphragm comprises a number of superposed layers of woven material bonded together so as to be impermeable to fluid, the warp and weft of at least one layer being both inclined to the warp and weft of an adjacent layer. The woven material may be made from natural or synthetic fibres or filaments, including metal, glass, rayon and nylon and the bonding cement may be natural rubber or neoprene synthetic rubber. Nylon fabric scoured or drycleaned and dried is given two coats of neoprene cement, the first of which contains a polyisocyanate in addition to the other ingredients which are neoprene, zinc oxide, magnesia, antioxidants, carbon black, stearic acid, paraffin wax, dibutyl phthalate, and benzene, being dried after each coating. Two pieces of coated fabric are superposed with the coated sides together, so that their warps cross at 45 degrees. Both sides of the compound fabric are coated with a number of layers of neoprene cement to give a smooth surface, and treated with zinc stearate. Blanks cut from the resulting fabric are vulcanised in moulds, opensteam-treated to relieve stresses, and dried.