GB977182A - Centrifugal pumps - Google Patents

Abstract

977,182. Seals. DENVER EQUIPMENT CO. May 23, 1961 [June 8, 1960], No. 18665/61. Heading F2B. [Also in Division F1] The shaft 11 of a centrifugal pump, Fig. 1, having an axial inlet port 15 and a tangential outlet port 16, is sealed where it extends through an opening into the pump housing H opposite the inlet by a flexible seal S which is closed by its resilience and by liquid pressure when the impeller R is stationary and which, when the impeller is rotated to pump liquid, is opened by the suction created by the liquid being drawn away from the opening by means of vanes 24 provided on the rear side of the impeller and by the effect of centrifugal force due to rotation of the seal S with the shaft. The opening for the shaft is formed between a sleeve 36 secured to the shaft and a blind plate 35 secured to the housing. The seal S, Fig. 3, consists of a rubber or resilient plastic disc having an offset portion 43 and moulded to a frame comprising a ring 3 to which are riveted resilient flanged fingers 39 which are embedded in the disc. In a modification, Fig. 7, the portion 43<SP>1</SP> has an annular coil spring 46 located at its centre of gravity. The ring 38 is held between the sleeve 36 and the hub 14 of the impeller. When the impeller is stationary the portion 43 of the seal is urged against the blind plate 35 by the resilient fingers 39 and by the pressure of the liquid in the housing and prevents leakage of the liquid between the sleeve 36 and the blind plate 35. Upon rotation of the impeller, in addition to the suction produced by the vanes 24, centrifugal force acts on the offset portion 43 of the seal to move it out of contact with the blind plate 35.