| 摘要 |
1,063,096. Centrifugal pumps. U. M. W. BARSKE and W. MURRAY. May 22, 1964, No.21293/64. Heading F1C. In a centrifugal pump having an impeller and at least one axial inlet (43), a bank of rotatable discs 40 defining annuli coaxial with the rotational axis, induce flow from the inlet to the impeller blades 32 whilst substantially eliminating cavitation in the inlet under conditions of low inlet head and high rotational speed, for example, about 1 p. s. i. above the vapour pressure and above 2000 r.p.m. respectively. The faces of the discs may be roughened to increase flow. The discs 40 may be spaced 0À050-0À125 inches apart. The discs may be spaced by a number of tongues (74), Fig. 6 (not shown), bent out of the plane of each disc (40) at the periphery thereof to form axially extending spacers, and the entry ends of the impeller blades (32) are located in the resulting slots (73), Fig. 7 (not shown). The end ring (58), after assembly, is angularly rotated a small amount in a slot (72), Fig. 3 (not shown) in each impeller blade (32) and secured in this position by pushing lips (75) against it. In alternative embodiments, Figs. 8 and 11 (not shown), the discs (40) are spaced by rectangular rings (77, 78) and I-shaped strips (79, 81) respectively, the ends (78) of the rings and those (81) of the strips being bent upwardly to engage the sides of the impeller blades (32). Moreover, the discs (40) are made oversize and are flattened at those positions on their peripheries to be received by the entry ends of the impeller blades (32). In another embodiment, Figs. 14 to 18 (not shown), having a fully shrouded impeller with discharge nozzles through its peripheral wall, each disc (40) is radially sprung into slots in the entry ends of the impeller blades, the impeller being radially split, to permit assembly of the discs (40), into a part comprising the back plate and peripheral wall and a part comprising the front plate and blades, the two parts subsequently being riveted or bolted together. Alternatively, the blades may be arranged on the back plate. Moreover, if the number of impeller blades is six or a greater even number then every second or third blade only need be provided with slots, the remainder being out of, or in loose contact with the discs (40). |
