GB1295808A - - Google Patents

Abstract

1295808 Seals UNITED STIRLING (SWEDEN) AB & CO KB 1 June 1971 18261/71 Heading F2B A seal for a piston-rod of a hot gas engine comprises an element 4 accommodating sealing means 5 (e.g. labyrinth seal) which allows restricted passage of leakage gas from a chamber 1 containing gas at high cyclically-varying pressure to a gas-filled space (e.g. a crank-case), in which the pressure is lower, and a return conduit 6 which returns the leakage gas to the chamber via a non-return valve 7. The pistonrod passes through the element 4 which is sealed to the chamber 1 by an 0-ring which allows radial movements. The element 4 contains the labyrinth seal 5, an 0-ring seal 17, an annular gas space connected to the return conduit 6 and an annular oil-space 10 which is fed with oil from a pump 11 controlled by a switch 16 operable by a magnet 15 mounted on a flexible diaphragm 14. The diaphragm responds to the pressure difference between the gas space and the oil space and ensures a supply of oil at a pressure set above that of the gas space. Oil entering the gas space is drained off through an oil separator 8. The leakage gas is sucked back to the chamber 1 when the cyclic pressure is low below the piston.