| 摘要 |
<p>A hydrostatic seal for the upright shaft of a coolant circulating pump in a nuclear reactor plant has a first sealing element which is affixed to the shaft and a second sealing element which is axially movably mounted in the pump housing and defines with the first sealing element an annular control clearance gap wherein leak fluid flows from a high-pressure compartment which surrounds the sealing elements to a low-pressure compartment between the shaft and the housing. An auxiliary pump causes the fluid to circulate in response to rotation of the shaft along an endless path which is defined by the high-pressure compartment, an annular space a portion of which is adjacent to that end face of the second sealing element which is remote from the gap, a flow restrictor between the high-pressure compartment and the space, one or more passages which are machined into the housing, and a chamber which communicates with the high-pressure compartment by way of the auxiliary pump. The passage or passages can deliver fluid to a conditioning chamber wherein the fluid is cooled to prevent undue thermally induced deformation of the sealing elements. The pressure differential which is established by the flow restrictor insures that the pressure in the outer region of the gap invariably exceeds the pressure at the aforementioned end face of the second sealing element whenever the pump shaft rotates to thus prevent frictional contact between those surfaces of the sealing elements which flank the gap.</p> |
