Dry gas seal for machine shaft - has aerodynamic lubrication with safeguard against running dry

摘要

The dry gas seal for a rotating shaft (1) which passes through a housing wall (2) is designed as an axial slide ring seal whose glide face (9') is pressed against the sealing face (6) by a gas. A relief device (19) is provided which with the reversal of the rotary direction of the shaft or relative rotation between the sealing face and glide face produces a force against the pressing direction of the slide ring against the sealing face. The relief device (19) can have an inclined guide (21') provided on the outer rim (11) of the glide ring (7) or opposite face (20) of a sealing holder (7). USE/ADVANTAGE - The shaft seal is prevented from jamming or damage when the shaft runs opposite the proposed direction.