FORCE BALANCED SPLIT RING DYNAMIC SHAFT SEALS
A dynamic shaft seal assembly of the piston ring type includes means for generating servoforces at the seal interfaces to reduce rubbing loads and wear. The servoforces are generated by venting the bottom of a groove which supports the seal ring and by providing passageways through the seal ring to pressurize the low pressure face and the outer face thereof. The forces thus generated vary in response to changes in the dimension of the gap between the seal ring and the seal seats with the overall axial forces tending to center the seal ring in the groove. Leakage is controlled primarily by varying the dimension of a radial passageway formed between the high pressure face of the seal ring and one of the axial seats.
***ZHAI ZI BAIDU XUESHU