CONTACTLESS END SEAL Russian patent published in 1997 - IPC

FIELD: hydraulic machinery engineering; multi-mode turbomachines, especially cantilever compressor machines. SUBSTANCE: contactless end seal includes working gas flow rate limiter made in form of labyrinth and two sealing stages mounted in single housing in series. Each sealing stage is provided with seal ring which is movable axially and is locked against turn. Sealing ring is provided with projection formed due to stepped change of thickness of ring on side of inner diameter. This ring is tightly fitted in housing on flexible members by means of secondary seal forming sealing slot with revolving ring flexibly fitted on shaft; it is also provided with clearance control device made in form of circular stepped sealing surface having recess on side of periphery on end face of revolving ring with ribs located in zone of recess of stepped surface from step to periphery of ring; they have lesser height as compared with step; they are directed towards high-pressure cavity and are inclined in direction of rotation of shaft. This device may be also made in form of circular bores in outer cylindrical surface of revolving ring, thin-wall projection on sealing ring with bore at its base on the reverse of ring mounted for secondary rubber seal on side of sealing ring and housing of movable circular member made from polymer possessing increased antifriction properties; provision is made for unloading over inner cylindrical bearing surface of member. Construction of seal provides for amount and shape of clearance during operation of turbomachine excluding effect of start-stop mode on serviceability of end seal. EFFECT: enhanced stability of time characteristics, enhanced efficiency and increased service life. 4 dwg