GB836945A - Self-priming centrifugal pump - Google Patents

Abstract

836,945. Centrifugal pumps. WORTHING- TON CORPORATION. Dec. 16, 1957, No. 39003/57. Class 110 (1). A self-priming centrifugal pump comprises a separating chamber connected to the pump casing to receive fluid from the discharge, and a tube extending into the casing to recirculate fluid from the separating chamber to the casing, the tube being of such length that the leading and trailing edges of the end of the tube have a close clearance with the outer periphery of the impeller. In the centrifugal pump shown, the pumped liquid is discharged through an outlet 75 into a separating chamber 78, where entrained air separates out from the liquid. During priming, liquid freed from air is recirculated from the separating chamber 78 back into the pump volute 73 through a tube 80 which has a threaded portion by which it is screwed into the volute. The pump is assembled with an impeller 74 of the diameter necessary to give the required pump duty, and the tube 80 is screwed into the volute 73 until the leading and trailing edges of its slanted end have a close clearance with the impeller periphery. The tube 80 is held in adjusted position by a key 81. The tube 80 may instead be integral with the volute and cut to the length required to suit the size of impeller used. As a further alternative, the tube may be carried by a flange which is interposed between the mating flanges 76, 79a of the volute and separating chamber. If the impeller is changed for one of different diameter, the tube can be replaced by another flanged tube of appropriate length.