| 摘要 |
A seal assembly for sealing a space between a rotary shaft (44) and a stationary member (10) includes a housing (66) having a bearing (90) that maintains the housing (66) true on the shaft (44). Seal assemblies (103, 105 and 107) axially spaced along the shaft (44) are connected via pressure relief valves (134) (Fig. 2) so that e.g. pressure above a predetermined limit across a first ring (103) passes to a second ring (105) and when the threshold at ring (105) is exceeded, pressure passes to third ring (107). In this way, at high pressures all three seal assemblies (103, 105 and 107) are active. A normally inactive back-up seal (109) may be provided. The seal assembly may be water lubricated. A split lap-jointed structure for a sleeve (110) forming part of the seal assemblies (103 to 109) and the curvature of the sleeve (110) relative to shaft diameter are also described. |
