Back-flushing pump of circulating water filtering system for nuclear power station

Abstract

The invention discloses a back-flushing pump of a circulating water filtering system for a nuclear power station, which is a vertical single-stage single-suction centrifugal pump. The back-flushing pump comprises a stator assembly, a rotor assembly, a bearing assembly, a shaft seal assembly and a motor. The stator assembly comprises a pump body, a pump cover, a bearing bracket and a motor frame; the rotor assembly comprises an impeller, a pump shaft connected with the impeller through an impeller nut and a shaft sleeve sleeved at an upper middle part of the pump shaft; the pump body adopts a radial split type double-volute structure; the bearing bracket comprises an intermediate bracket and a bearing body; the outer edge of the pump cover is clamped between the upper end of the inner edge of the pump body and the lower end of the inner edge of the intermediate bracket; the bearing assembly comprises a pair of angular contact ball bearings installed in a cavity of the bearing body in a back-to-back mode and sleeved at the upper middle part of the pump shaft, a set of guide bearings arranged between the lower part of the pump shaft and the inner edge of the pump cover and an upper bearing cover; and the shaft sealing assembly comprises a pump body seal installed at the upper end of the pump cover and a bearing oil seal which is installed in the cavity of the bearing body and arranged at the lower ends of the angular contact ball bearings.

Description

technical field [0001] The invention relates to a pump, in particular to a backwash pump used in a circulating water filtering system of a nuclear power plant. Background technique [0002] The rotation speed of the backwash pump in the existing circulating water filtration system is 1480r / min. Since the torque received by the bearing is inversely proportional to the rotation speed under the condition of a certain transmission power, two pairs of separately installed bearings are required. Therefore, the overall size of the original pump is relatively small. Large, the weight of the rotor is also heavy. The volute pump body of the backwash pump in the circulating water filtration system adopts a single channel, so that the radial force of the impeller at the non-design working point is not balanced enough, so the hydraulic performance is poor; the bearing body and the bracket are integrated. It is very inconvenient for inspection and maintenance; in addition, the bearing is...

AI Technical Summary

Problems solved by technology

The volute pump body of the backwash pump in the circulating water filtration system adopts a single channel, so that the radial force of the impeller at the non-design working point is not balanced enough, so the hydraulic performance is poor; the bearing body and the bracket are integrated. It is very inconvenient for inspection and maintenance; in addition, the bearings are lubricated with thin oil, and an additional lubricating oil circulation system needs to be installed, thus increasing the complexity of the system

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