| 摘要 |
A rotodynamic fluid machine such as a pump (10) comprising a pump casing (11) defining a pump chamber (13) in which a pump impeller (15) is rotatably supported on a pump shaft (19). The pump shaft (19) is rotatably supported on a bearing assembly (21). A seal assembly (31) is provided between the pump casing (11) and the bearing assembly (21). The seal assembly (31) comprises a seal casing (33) attached to the bearing housing (21). A shaft sleeve (61) is mounted on the end section of the pump shaft (19) adjacent the impeller (15) for rotation therewith. The seal assembly (31) comprises a first seal (91), a second seal (92) and a seal chamber (93) therebetween. The first seal (91) is at the atmospheric end of the seal chamber (93) and the second seal (92) is at the fluid end of the seal chamber so as to be exposed to the pump chamber (13). The first seal (91) is in the form of a mechanical seal comprising a stationary seal element configured as a stationary seal ring (95) and a rotatable seal element configured as a rotatable seal ring (97). The second seal (92) comprises a lip seal (121) having a tip (25) for contact with the outer surface of the shaft sleeve (61). An inlet (141) is provided in the seal casing (33) to deliver flush fluid into the seal chamber (93). The flush fluid establishes a fluid pressure within the seal chamber (93) at a level slightly higher than the fluid pressure within the pump chamber (13), creating a pressure differential across the lip seal (121). As a consequence of the fluid pressure differential, there is restricted fluid flow (leakage) past the lip seal (121) from the seal chamber (93) into the pump chamber (13). The flush fluid serves to isolate the lip seal (12)1 from pumpage material being pumped within the pump chamber (13). WO 2008/141377 PCT/AU2008/000703 A~~~y 3%MEMEf/ un i aamminluia) 0-E' LO L - RE ~ L CiOE~M %21MOi ufm Cfwsn AllBM co CN .0 c? |
