Seal for a joint or juncture – Seal between relatively movable parts – Relatively rotatable radially extending sealing face member
Patent
1985-05-31
1987-09-15
Ward, Robert S.
Seal for a joint or juncture
Seal between relatively movable parts
Relatively rotatable radially extending sealing face member
277224, 277DIG6, 501 97, F16J 1520, C04B 3558
Patent
active
046934812
ABSTRACT:
An improved shaft seal for sealingly and rotatably mounting a torque-transmitting shaft within the pressurized housing of a pump. Generally, the shaft seal comprises a seal ring which is sealingly mounted within the housing, and a runner ring which is sealingly mounted around the shaft. Both the seal ring and the runner are preferably formed from 98% pure, hot-pressed silicon nitride. Additionally, the sealing surface of the seal ring is preferably radially tapered between about 635 and 645 microradians around its outer periphery, and between about 210 and 230 microradians around its inner periphery. The pressurized fluid within the housing enters the annular space between the two sealing surfaces and creates a flowing film of fluid upon which the two sealing surfaces may "ride" without frictionally engaging one another. The shaft seal of the invention is capable of operating in a film-riding mode despite broad variations in the pressure within the housing of the shaft, but is also capable of operating in a non-film-riding mode for long periods of time without damage, should the pump malfunction. The shaft seal finds particular application in the coolant pumps of nuclear steam generators.
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Ward Robert S.
Westinghouse Electric Corp.
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