| 摘要 |
1,250,062. Centrifugal pumps. ALLWEILER A.G. Feb.4, 1969 [March 26, 1968], No.5991/69. Heading F1C. A centrifugal pump comprises an impeller 4 mounted in a casing 1 so as to provide a suction chamber 18 on one side of the impeller and a pressure chamber 19 around the impeller, a casing cover 6 on the side remote from the suction chamber providing an enclosed space 17 between itself and the impeller, an annular gap seal 12 between the chambers 18, 19 provided by projections 10, 11, an annular gap seal 15 of larger diameter between the chamber 19 and the space 17 provided by projections 13, 14, and at least one throttle bore 16 through the impeller to provide a pressure drop, dependent on the dimensions of the throttle bore, between the space 17 and the chamber 18 to compensate for axial thrust on the impeller due to pressure in the chamber 19. A selected size of impeller 4 and casing 1 may be chosen from a range of sizes and attached to the cover 6, which remains unaltered. |
