| 摘要 |
A centrifugal pump is provided having a pump casing (16) and a seal housing (19). The pump includes a valve seat 58) on an interior wall surface of the seal housing (19), a valve member (64,65) and spring means (66 min ) urging the valve member (64,65) into sealed engagement with the valve seat (58) thereby isolating liquid retained in the seal housing (19) from the pump casing (16) when the pump is not in operation. Force responsive means (78) are also provided which are movable under centrifugal force to engage the valve member (64,65) and move it away from sealed engagement with the valve seat (58) thereby establishing fluid communication between the seal housing (19) and an expeller means (22,30) when the pump is in operation, the expeller means (22,30) expelling the liquid retained in the seal housing (19) through a fluid channel (39,40,41) when the pump starts into operation. |
