GB927609A - Improvements in sealing devices for hydraulic systems - Google Patents

Abstract

927,609. Stuffing-box substitutes. VOLVO A.B. Feb. 15, 1960 [Feb. 18, 1959], No. 5358/60. Class 122 (5). A sealing device between the piston-rod or like member 1 of an hydraulic device and a fixed housing 4 comprises an elastic sealing ring 10 which has inner arid outer cylindrical surfaces 15, 16 bounded by end surfaces 17, 18 and is mounted in a structure 2 forming part of the housing 4 so that at one corner of the ring its cylindrical surface 16 and adjacent part of its end surface 18 are engaged by the inner wall and radially-projecting shoulder 12 of the structure 2 and a spring 5 acts on the ring at its diagonally-opposite corner. The action of the spring in conjunction with the wall 16 and shoulder 12 is such that the compression of the ring results in the contact pressure between it and the sliding surface of the piston-rod 1 having the distribution shown by the curve 23, 24, 25. Because of the high increase in contact pressure per unit of length as shown by the curve 24 only a thin film of the liquid which escapes past a lower packing 6 to a chamber 8 is carried past the ring 10 upon upward movement of the piston-rod and the film is easily returned upon reversal of the piston-rod because of the contact pressure distribution as shown by the curve 23. The spring 13, preferably in the form of a number of conical discs, is compressed between the ring 10 and a part 3, all these parts being enclosed by the member 2 which is screwed on to the housing 4. The chamber 8 housing the spring 13 communicates with a return duct 9 and serves as a chamber for liquid leaking through the clearance 7 between the rod 1 and part 3 from the seal 6.