초록 ▼

A pump having a shaft and housing containing pressurized system fluid variable between low pressure at pump startup and high pressure at pump operation, employs a hydrostatic sealing assembly for sealably and rotatably mounting the shaft within the housing. In the assembly, both a runner mounted aro

A pump having a shaft and housing containing pressurized system fluid variable between low pressure at pump startup and high pressure at pump operation, employs a hydrostatic sealing assembly for sealably and rotatably mounting the shaft within the housing. In the assembly, both a runner mounted around the shaft for rotation therewith and a seal ring mounted to the housing have facing surfaces between which pressurized system fluid creates a flowing low pressure fluid film which prevents contact between the facing surfaces so long as a predetermined minimum leakrate is maintained therebetween. First and third seal ring surfaces face in opposite directions with the second surface facing in the same direction as faced by the seal ring facing surface. First and second chambers are defined contiguous to the first and second surfaces with the first chamber in communication with pressurized system fluid and isolated from the second chamber and with the latter isolated from the runner and seal ring facing surfaces. Pressurized balance fluid provided to the second chamber via a passage through the housing from the exterior thereof is at a balance pressure greater than the supply pressure of the system fluid such that the balance pressure is effective at pump startup when the supply pressure is low, and ineffective at pump operation when the supply pressure is high, to counter a seating force imposed on the seal ring first surface by the supply pressure and augment a lifting force imposed on the seal ring facing surface by the supply pressure so that at both pump startup and operation leakrates are produced between the runner and seal ring facing surfaces which are above the predetermined minimum.

대표청구항 ▼

In combination, a pump having a shaft and a housing having an exterior and an interior for containing pressurized system fluid, an external system fluid source for providing pressurized system fluid to said housing interior at a supply pressure which is variable between a low pressure at pump startu

In combination, a pump having a shaft and a housing having an exterior and an interior for containing pressurized system fluid, an external system fluid source for providing pressurized system fluid to said housing interior at a supply pressure which is variable between a low pressure at pump startup and a high pressure at pump operation, and a hydrostatic sealing assembly for sealably and rotatably mounting said shaft within said housing interior, said sealing assembly comprising: (a) an annular runner circumscribing and mounted around said shaft for rotation therewith; (b) an annular seal ring circumscribing and mounted within said housing interior in non-rotational relationship thereto but for translatory movement along said shaft and said housing; (c) said runner and seal ring having surfaces facing one another and between which pressurized system fluid within said housing interior creates a flowing film of low pressure fluid which prevents said facing surfaces of said respective runner and seal ring from coming into contact with one another so long as a predetermined minimum leakrate is maintained therebetween; (d) means defining first and second surfaces on said seal ring facing in directions opposite to one another and in sealingly isoated relationship from one another, said first surface on said seal ring being in flow communication with pressurized system fluid at said supply pressure thereof within said housing interior and facing in a direction opposite to that faced by said facing surface on said seal ring, said second surface on said seal ring being in sealingly isolated relationship with respect to said facing surfaces on said runner and seal ring and facing in a direction the same at that faced by said facing surface on said seal ring; (e) an external balance fluid source for providing pressurized balance fluid to said second surface on said seal ring at a balance pressure which augments said supply pressure of the pressurized system fluid by a constant differential pressure that is effective at pump startup when said supply pressure is low, and ineffective at pump operation when said supply pressure is high, to counter a seating force imposed on said seal ring first surface by said supply pressure and augment a lifting force imposed on said seal ring facing surface by said supply pressure so that at both pump startup and operation leakrates are produced between said facing surfaces of said runner and seal ring which are above said predetermined minimum thereof; and (g) means for providing flow communication or pressurized balance fluid from said external balance fluid source to said second surface of said seal ring.