Multistage sectional type centrifugal pump with function of balancing axial force by self

Abstract

The invention discloses a multistage sectional type centrifugal pump with a function of balancing an axial force by self. At least two stages of impellers are arranged on a pump shaft; the radius of a front hub of each stage of the impeller is smaller than the radius of the rear hub of the impeller; the radius of a rear hub of a front stage of impeller is equal to that of a front hub of a later stage of impeller; and the radius of a rear hub of a final stage of impeller is equal to that of a shaft end seal. The radiuses of the rear hubs of the impellers can be determined according to the radius of the front hub of each stage of the impeller, the radius of a front hub port ring of the impeller, the radiuses of impeller outlets and the liquid pressure intensity distribution rule on two sides of the impellers, liquid pressures on two sides of the impellers trend to be identical, and each stage of the impeller trends to have no axial forces, so that the axial force of a whole shaft system rotor of the multistage sectional type centrifugal pump is greatly reduced; and meanwhile multiple stages of impellers are arranged in a same direction without additional arranging an axial force balancing device, so that the multistage sectional type centrifugal pump is simple and compact in structure and has the advantages that the shaft system rotor has no axial movement, the liquid leakage among the impeller stages is small, and the like.

Description

technical field [0001] The invention relates to a multistage segmental centrifugal pump, in particular to a multistage segmental centrifugal pump capable of self-balancing axial force. Background technique [0002] The multi-stage segmented centrifugal pump has a simple structure and is widely used, but in use, due to the uneven distribution of liquid pressure on both sides of the impeller, that is, the liquid pressure on the wheel cover side is relatively low, and the liquid pressure on the wheel disc side is relatively high, so it will produce an The axial force parallel to the axis of the pump shaft is directed towards the impeller inlet. [0003] At present, there are mainly the following methods for axial force balance of multistage centrifugal pumps: ① symmetrically arranged impeller method, but this method requires that the number of impellers must be even, and the flow path of the centrifugal pump is complicated, and the structure of the pump body is complicated; ② a...

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Problems solved by technology

[0003] At present, there are mainly the following methods for axial force balance of multistage centrifugal pumps: ① symmetrically arranged impeller method, but this method requires that the number of impellers must be even, and the flow path of the centrifugal pump is complicated, and the structure of the pump body is complicated; ② at the end The disc side of the stage impeller adopts a balance drum structure, but the pressure difference between the two sides of the balance drum is large, resulting in a large liquid leakage in the gap of the balance drum, which makes the volumetric efficiency of the centrifugal pump low; Under the action, the transmission shaft runs under the pressure rod state, the wear of the mouth ring is serious, and the service life is low

③The automatic balance disc structure is adopted on the disc side of the final impeller, but the shaft rotor of the centrifugal pump with the balance disc structure must have a certain amount of axial movement. The axial movement of the shaft rotor is not conducive to the shaft end seal, making the shaft The end seal is easy to fail; at the same time, the axial movement of the shafting rotor is likely to cause wear between the rotor part and the stator part; in addition, the axial movement of the shafting rotor makes the centrifugal pump start, stop or when the flow head changes. It will produce impact and collision, increase the friction and wear of parts, cause the balance plate to be easily damaged, and need to be replaced frequently, reduce the service life of the centrifugal pump, and increase the maintenance cost of the centrifugal pump

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