Reactor coolant pump hydrostatic sealing assembly with improved hydraulic balance

摘要

A pump (14) having a shaft (34) and a housing (32) containing pressurized fluid variable in pressure between pump startup and operation employs a hydrostatic sealing assembly (82) for sealably and rotatably mounting the shaft (34) within the housing (32), which includes a runner (44) mounted around the shaft (34) for rotation therewith and a seal ring (84) mounted to the stationary housing. A flow control device (114) provided in the seal ring (84) is automatically operable in response to the supply pressure level to open communication of the pressur­ized fluid supply pressure with a seal ring second surface (88) at pump operation and to open communication of a fluid film low pressure between the runner 44 and seal ring 84 facing surfaces (64, 92) with the seal ring second surface (88) at pump startup.