GB799335A - Improvements in or relating to flexible pump-diaphragms - Google Patents

Abstract

799,335. Diaphragm pistons. CRANE PACKING CO. Nov. 30, 1955, No. 34333/55. Class 122 (1). [Also in Group XXIX] A flexible pump diaphragm for fuel pumps, valves, &c., comprises a disc of flexible material having solid unbroken central and rim portions 16 and 10 respectively, integrally connected by an intermediate portion formed by laminations 18. The rim portion 10 is offset from the central portions 12 by a taper portion 14. A number of diaphragm blanks 29, Fig. 6, may be produced from cylindrical stock 24 by successively making a series of spaced cuts of required depth into the stock by a cutter 28 to form the laminations 18, the last cut required for a diaphragm being carried through the cylinder to separate the blank from the stock. Each blank is then clamped in a mould having upper and lower co-operating dies 30; 32, Fig. 4, each comprising a central section 34, 40 separated by a heatinsulating ring 38, 44, from a surrounding concentric section 36, 42, heated by a heating band 54 whereby the laminations in the outer peripheral regions of the blank are heat sealed together to form the solid rim 10. In a modification, Fig. 3 (not shown), the diaphragm is made from a number of superimposed annular layers of material heat sealed together, in a mould similar to that shown in Fig. 4, at their inner and outer peripheral portions only, and separated at their intermediate portions, if desired, by thin rings of metal foil. The diaphragm material may be the polytetrafluoroethylene polymer sold under the Trade name " Teflon."