GB1100053A - Sealing devices - Google Patents

Abstract

1,100,053. Piston packing; shaft seals. DOWTY SEALS Ltd. 27 May, 1966 [1 June, 1965], No. 23303/65. Headings F2B and F2T. A sealing device between two relatively slidable members, e.g. a piston 11 and a cylinder 12, comprises an annular recess in one, 11, of the members, two axially spaced backing rings 18, 19 extending from opposite ends of the recess, and sealing means including an annular body 21 of resilient material disposed within the recess so that it engages the rings 18, 19, and forms with the base 13 of the recess a fluidreceiving cavity 20 and an annular flange 22 of resilient material which extends radially from the body 21 between the rings 18, 19 into sealing contact with the other member 12. The ring body 21 has axial clearance in the recess and the flange 22 is axially movable between the rings 18, 19. In operation, fluid pressure from the high-pressure side of the seal-the left hand side in Fig. 1-is admitted to the cavity 20 past the adjacent backing ring 18 and causes the body 21 to be pressed axially against the end wall 15 of the recess and radially outwardly against the flange 22 and the backing ring 19 on the lowpressure side of the seal. The body 21 may be of natural or synthetic rubber, the flange 22 of polyurethane or P.T.F.E., and the rings 18 and 19 of nylon. In a modification, Fig. 2 (not shown), the body and flange are integral (26) and the backing rings (27, 28) are helically formed. The invention may be used as a shaft seal.