Patent ID: 6517077
Filing Date: 2003-02-11
Classification: F16J

Abstract:
A seal assembly for providing a liquid-tight seal about a revolving shaft, the seal assembly comprising:at least two relatively rotatable rings for disposition about the shaft, the rings having sliding faces confronting each other; a control mechanism including a piston coupled to one of the rings and selectively operable to (1) urge the one ring toward and away from the other ring between (a) a first position in which the sliding faces engage each other and pressure is established between the sliding faces and (b) a second position in which the sliding faces are separated by a gap and (2) control respectively (a) the pressure of the sliding faces against each other and (b) the magnitude of the gap between the sliding faces, the piston having opposed faces exposed to fluid pressure in two chambers separated by the piston; and means for selectively introducing fluid under pressure into the chambers to thereby create a force on the piston that urges the one ring toward and away from the other ring.