GB1254715A - Centrifugal pumping apparatus - Google Patents

Abstract

1,254,715. Centrifugal pumps. SHIMADZU SEISAKUSHO Ltd. Nov. 22, 1968 [Dec. 1 1, 1967(2)], No. 55600/68. Heading F1C. In a centrifugal pump of the type in which fluid is conveyed between liquid partitions moving centrifugally along passages in impeller 47, Fig. 13 the passages 54 are of involute form and have their inlet ends arranged closely adjacent one another, Fig. 14 (not shown). The liquid which forms the partitions is supplied through a nozzle member 39. The supply pipe of the nozzle member may be associated with a piston and cylinder arrangement to provide a pulsating motion to the liquid in the pipe, Figs. 5 and 6 (not shown).. Alternatively, the nozzle member may be rotated about the impeller axis in the same or opposite direction and at a different speed to that of the impeller, Fig. 7 (not shown). In another arrangement, Figs. 8 and 9 (not shown), the nozzle member is oscillated about the impeller axis via a mechanism comprising a cam which is driven through a gear train by the impeller shaft and which co-operates with a rod extending radially from the nozzle member. The nozzle member may instead be intermittently rotated in one direction. The pump may include means for recirculating the partitioning liquid. For this purpose the pump of Fig. 13 includes a rotary internally-vaned member 31b which, during operation, causes the liquid to uncover the impeller as shown and to return to the nozzle member via openings 120 and 53b at the central region of the member 31b, i. e. the region where the liquid is normally free of any solid particles. Fig. 10 shows a pump having a downwardly-dished impeller and a collector 67 for the partitioning liquid, the level of the liquid in the collector being normally above the nozzle member to thereby create a recirculatory flow back to the nozzle member via supply pipe 38. The latter may be omitted and the bottom of the collector is then connected with the nozzle member from a position below the impeller. In such an arrangement a connecting passage extending upwardly along the impeller axis is provided with a valve (110), Fig. 11 (not shown), for controlling the flow of recirculated liquid. In another arrangement, Fig. 12 (not shown), devoid of pipe 38 and collector 67, the partitioning liquid discharged from the impeller into a surrounding chamber (b) is recirculated by a screw impeller (114) located below the main impeller, and the flow of recirculated liquid is controlled by a valve (116). The pump inlet may be provided with a reverse-flow-preventing device, Fig. 15 (not shown), comprises a rotary vaned member which is rotated during operation of the pump, but is stopped during shut down so that the vanes act as baffles.