Eccentric face seal with asymmetric closing force.

摘要

In an eccentric face seal for rotary machines, the closing force (FH, FL) of the seal faces (5, 6) towards one another is asymmetric. The asymmetric closing force is utilized to produce corresponding variations in the face seal gap which tends to produce fluid flow across the seal face in a direction opposite to the leakage produced by the pressure difference, and thereby eliminate or reduce leakage. Closing forces can be applied by at least a pair of springs (7, 8) providing different compressive forces or by hydraulic actuator means in which the total combined forces can readily be made to vary with fluid operating pressure. In one embodiment the hydraulic actuator means are provided by asymmetric pressure responsive areas of the rotor or stator.