GB1257897A - - Google Patents

Abstract

1,257,897. Circumferential-flow pumps. SIEMEN & HINSCH m.b.H. July 2, 1970 [July 5, 1969], No.32135/70. Heading F1C. In a side-channel circumferential-flow pump with a horizontal shaft 5, an annular suction chamber 6, a port 8 from the suction chamber to the pumping area, the port being situated to the side of the impeller 7 and on a level with or lower than the shaft, and a dividing wall 9 in the suction chamber, the inlet 3, leading straight into the suction chamber, is situated on the underside and pointing downwards so as to avoid bends in the intake pipe leading down to an underground tank. Although this disposition of the inlet 3 allows most of the liquid to flow back from the pump casing to the tank when the pump is stopped, re-priming is ensured by providing ribs 10, 11 in the suction chamber 6 and a short distance before the port 8, each rib covering the entire axial width and substantially half the radial depth of the suction chamber. During priming, liquid flung out of the side channel 12 into the suction chamber 6 by the impeller 7 while air is being removed from the system is trapped by the ribs 10, 11 and returned to the pumping area via the port 8. As shown, the rib 11 may precede the rib 10 in the direction of flow, and both ribs may be inclined or bent towards the port 8. Advantageously, the direction of impeller rotation may be opposite to the direction of flow through the suction chamber.