GB1292983A - Improvements in or relating to sealing devices - Google Patents

Abstract

1292983 End-face seals ROLLS-ROYCE Ltd 19 Feb 1970 [19 Feb 1969] 8977/69 Heading F2B A seal between relatively rotatable structures (e.g. a turbine or compressor disc 14 and a stationary part 18 of a gas turbine engine) and separating high and low pressure zones comprises a seal ring 22 which is resiliently-mounted on, for example, the stationary part of the engine as by spring-bellows 20 and is arranged to form with one or more annular grooves 26 a variable pressure chamber in communication with the high pressure zone, the arrangement being such that as the clearance decreases the pressure in the chamber rises and vice-versa, the resultant pressure acting on the seal ring as the clearance varies to maintain the clearance at a substantially constant valve and provide a balanced seal. The grooves 26 on the rotary disc may be formed by ribs 28, 30, Fig. 3 (not shown), three of which are made longer than the rest to reduce the area of rubbing contact should the clearance be reduced to zero. Bores 24 communicate between the interior of the bellows 20 and the seal face of the ring 22. In an alternative arrangement, the seal ring 22 may be in the form of an annular piston which is spring-mounted on the stationary part 18 and engages in an annular cylinder secured to the rotary part, the chamber formed by the piston and cylinder being in communication with the upstream face of the piston by means of bores 24.