| 摘要 |
903,904. Centrifugal pumps; stuffing-box substitutes. WILFLEY & SONS Inc., A.R. March 6, 1961 [Aug. 3, 1960], No. 8019/61. Classes 110 (1) and 122 (5). In a centrifugal pump provided with means for shifting the impeller shaft to open a shaft seal whereby rubbing contact between the rotating and stationary parts of the seal is eliminated during operation of the pump, the impeller, the seal and the portions of the pump casing adjacent the impeller are formed of corrosion-resistant material. When the pump is stationary, a seal ring 75 carried by the impeller shaft abuts a stationary seal ring 102 to prevent leakage. When the pump is running, a centrifugal device c moves the impeller shaft to the left as described in Specification 643,247 to separate the seal rings 75, 102 and eliminate rubbing contact between them, leakage being opposed by auxiliary impeller passages 154, assisted by a labyrinth gland 112, 159. Leakage is drained through a spout 105. The passages 154 are longer than the main pumping passages 152, each main or auxiliary passage having a straight non-radial axis but one bounding edge of each passage being radial. The pump casing comprises a front plate 90, a volute ring 91 and a back plate 92, clamped to a supporting bracket B by bolts 95 and provided respectively with liners 116, 127 and 111 which are cemented in place. The impeller 72, the liners 111, 116, 127, the seal rings 75, 102 and shaft sleeves 70, 80 are formed of corrosion-resistant material. Surfaces of a seal ring housing 100 which are in contact with the liquid being pumped are coated with the corrosion - resistant material. Suitable corrosion-resistant materials include ceramics, refractories, vitreous materials (including glass), plastics and high silica irons. |
