Patent GB-1506956-A (GB)
Title: Pumps
IPC: F04D5/00
Filed: 1975-11-12
Abstract: 1506956 Circumferential flow pumps ROY E ROTH CO 12 Nov 1975 [24 July 1975] 46729/75 Heading F1C A multi-stage pump comprises a casing having a number of successive stage casing rings between which are interposed transfer plates having fluid passageways means presenting an entrance communicating with the interior of the preceding casing ring and an exit communicating with the succeeding casing ring, a suction end casing section abutting the first-stage casing ring, a discharge end casing section abutting the last-stage casing ring, means securing all these elements together, a shaft extending axially through the casing, and an impeller within each casing ring and secured to the shaft. The pump may have any number of stages, a two-stage embodiment being shown in Fig. 3 in which the casing comprises a suction end casing section 24, first-stage casing ring 26, a transfer plate 28, second-stage casing ring 30, and a discharge end casing section 32, which are clamped together by tie-bolts 112. A suction connection 34 and a discharge connection 36 are securable to the end casing sections by means of bolts 120 in alternative angular positions as shown in Fig. 1. After removal of the bolts 120, the casing can be withdrawn from the connections 34, 36 without disturbing the connections or the pipes 124, 136 Instead of being threaded into the connections 34, 36 as shown, the pipes 124, 136 may instead be welded to them or attached via bolted flanges. The fluid entering the suction end casing section 24 from the suction connection 34 passes into an arcuate channel 44 from which it directly enters a notch 178 in an annular liner 174, Figs. 3 and 12, and also enters a notch 186 in a generally similar liner 176 via cut-outs 62, 64 Figs. 3 and 10, and a generally arcuate channel 80, Figs. 3 and 7, in the transfer plate 28. After being impelled around annular pumping channels 182, 190 by means of the first-stage impeller 152, the fluid passes to the inlet 82 of a generally arcuate channel 84 in the transfer plate 28, the fluid passing to this inlet from a notch 180 in the liner 174 via a cut-out 60 and directly from a similar notch in the liner 176. The channel 84 discharges the fluid to the secondstage casing ring 30 at a position angularly spaced by 180 degrees from the position at which the fluid entered the first-stage casing ring 26, to provide hydraulic balancing, the casing ring 30 being similar to the casing ring 26 but orientated 180 degrees out of phase with respect to the latter. In pumps having an even number of stages, the successive stages are displaced by 180 degrees. In the case of an odd number of stages, the displacement is 360 degrees divided by the number of stages. Bearing cartridges 204, 240 are clamped in place by means of caps 218, 258 and bolts 220, 260, the position of cartridge 204 being fixed while the position of cartridge 240 and therefore of the shaft and impellers is adjustable by means of a threaded ring 250, the adjustment being accommodated by a spring washer 217. Each impeller is keyed to the pump shaft and is located axially by means of collars 160, 162 which are fixed to the shaft by set screws 166, a spring washer 170 being  interposed between the impeller and the collar 162.