GB730357A - Improvements in or relating to centrifugal pumps - Google Patents

Abstract

730,357. Centrifugal pumps. SCHELLENS, C. A. July 21, 1953, No. 20196/53. Class 110(1). A centrifugal pump comprises a casing member having a stepped bore with an annular shoulder therein, and a circular diaphragm closing the bore and pressed against the shoulder. The casing of the pump is bolted to the casing 12, Fig. 1, of the driving means and comprises a main part 20 closed at each end by end plates 22, 24. An inner portion 50 of the casing is integral with the main part 20 and contains a volute 52. It has a bore stepped to provide shoulders 60, 62 which are engaged by flanges 68, 70 of diaphragms 64, 66, respectively. A diffuser is located between the diaphragms and preferably comprises two separate annular parts 72, 74, the latter carrying diffuser vanes 76. A ring 90 is screwed into a threaded portion of the bore until, it abuts the diaphragm 64 and is then slightly backed off. Bolts 94 are then tightened up against the diaphragm 64 to force the flanges 68, 70 into fluid-tight abutment against the shoulders 60, 62, the thrust being transmitted through flanges 96, 98 of the diffuser. Since the flanges 96, 98 are radially offset, the thrust slightly distorts the diffuser, producing a spring effect which holds the diaphragm 66 against the shoulder 62. The relative dimensions of the parts of the pump are such that assembly can be effected by passing the various parts, including the bearing 35 and its retainer 36, through the outboard opening which s subsequently closed by the end plate 22. Fig. 4 shows a modification in which the diffuser has a flange 106 which is a radial force fit against a shoulder 110 to prevent leakage, while the thrust is transmitted through a flange which is provided with a series of radial slots 114 to communicate the liquid pressure within the passage 84 to the back of the. diffuser part. 102. The diffuser parts 100, 102 are thus clamped together, by the pressure prevailing in the passage 84, which is greater than that, within the diffuser.