| 摘要 |
1,155,920. Shaft seals. A. R. WILFLEY & SONS Inc. 6 Sept., 1967 [17 May, 1967], No. 40653/67. Heading F2B. In a centrifugal pump the impeller shaft is sealed by means comprising a first sealing portion 152 fixed to the shaft and a second sealing portion 210 which is axially movable out of and into engagement with the first portion 152 by spring means 244 and 292 respectively, the spring means 292 being stronger than the spring means 244 so that when the shaft is at rest the portion 210 sealingly engages the portion 152, and speed responsive means, e.g., centrifugal weights 310, secured to the shaft and operating at a predetermined speed to overcome the spring means 292 and thus allow the sealing portion 210 to be disengaged by the spring means 244 when the pump is in operation. The sealing portion 152 is secured to the hub 136 of the pump impeller (138, Fig. 1). The sealing portion 210 is carried by a retainer sleeve 190 slidable in a housing 166 and secured to one end of each of three push rods 236 extending through a housing 230 and urged to the left by the springs 244. A yoke 262 secured to the other ends of the rods 236 abuts a flange 286 on an actuator body 280 which houses the spring 292 and is slidably mounted on a spider 272 secured to the shaft and pivotally carrying the weights 310. The retainer 190 is sealed to the housing 166 by seals 186 and 188. When the pump is at rest the sealing portion 210 is seated against the sealing portion 152 by the spring 292, as in Fig. 1 (not shown). When the shaft rotates the centrifugal weight 310 engages the body 280 and at a predetermined speed overcome the force of spring 292 thus allowing the portion 210 to be disengaged from portion 152 as in Fig. 2; shaft leakage then being prevented by auxiliary vanes 142 on the back of the pump impeller. Any leakage is drained through a passage 196 and a drain tube 202. |
