GB682123A - Improvements in and relating to centrifugal pumps - Google Patents

Abstract

682,123. Centrifugal pumps. NAAMLOOZE VENNOOTSCHAP MEPPELER MACHINEFABRIEK EN TECHNISCHE HANDEL MAATSCAPPIJ VOORHEEN. F. HUISMAN. Dec. 1, 1950, No. 29444/50. Class 110(i) A self-priming centrifugal pump comprises a shrouded impeller on a horizontal shaft, with a stationary wall on each side of the impeller, the space between each wall and the impeller communicating, at a smaller radius than that of the impeller periphery, with a passage which leads to a space at the bottom of the casing. In a twostage centrifugal pump, Fig. 1, the second stage impeller 13 revolves between stationary side walls 31, 41, and delivers by way of periphery spaced channels 28 which open into an annular passage 25 leading by way of a central opening 29 to the discharge 2. When the pump is started, water which has previously collected at the bottom of the casing 1 flows by way of passages 35, 34, 33 and 36 to the space between the wall 31 and the impeller 13 and by way of passages 45, 44 to the space 42. The water is flung outwardly by the rotation of the impeller 13, and seals the clearances between the impeller periphery and the adjacent casing parts. Stationary blades 37, 43 may be provided to retard the flow of the sealing water and thus increase the time available for priming. The first stage impeller 12 is housed in a casing 4 which, together with a cover 7, is bolted to the main casing 1. An insertion 15 contains the interstage flow passage 20. In the modification shown in Fig. 4, a discharge volute 24a extends through slightly more than 360 degrees, ending at 50, just past the discharge 2. The water leaving the volute 24a flows around the outside of the volute before reaching the discharge 2, so that the bottom 51 of the pump casing is kept filled.