GB1396864A - Tubular seals - Google Patents

Abstract

1396864 Rolling-seals H T STORR 25 Aug 1972 [25 Aug 1971 24 Sept 1971] 39993/71 and 44698/71 Headings F2T and F2B A rolling-seal for a reciprocating shaft or piston comprises a flexible tube 3 turned back on itself to form an annular recess at the or each end and means such as a sleeve 6 for controlling the movement of the or one of the convolutions, the portions of the tube radially inwardly and outwardly of the recess each being anchored on the respective moving part. As shown in Fig. 1, the flexible tube 3 is turned back at both ends, the middle part of the tube being bonded in a recess 20 of a piston while the two ends are clamped to the cylinder. The tube 3 may be made of nylon, polythene or P.V.C. and the movement controlling means for the upper convolution may be spring-urged sleeve 6 which is restricted in its movements by a peg 19 operating in a helical groove 18 and acts through a thrust race 5 and a ring 4. The pressures on each side of the tube 3 are equalized by ducts 14 and 15 which allow passage of fluid from the lower side of the piston. Cooling of the piston and cylinder is effected by passing coolant from an inlet 11 centrally down a passage 12 and back to an outlet 13 which delivers the coolant through a flexible tube 9 to cylinder jackets 16a, 16b and outlet 17. As shown in Fig. 8, opposed pistons 102, 104 are sealed by rolling-seals formed by a flexible tube 110 which is clamped to the pistons by bolts 132 and supported by springs 140, 142 and 144 and rings 136, 138. In Fig. 2 (not shown), valves (48, 50 and 52) allow switching from automatic to external control of the pressurizing fluid to each side of the rolling seal and in Fig. 3 (not shown), the pressurizing fluid is fed through the piston. In Figs. 4 and 5 (not shown), a tube 55 turned back only at one end is employed.