Multi-stage shielded electric pump with back-to-back impeller arrangement

Abstract

The invention relates to a multi-stage shielded electric pump with back-to-back impeller arrangement, which comprises a motor and a pump. In an improvement, two groups of impellers respectively comprise a group of positive impellers and a group of negative impellers; the positive impellers are arranged on a rotor shaft on one side of a pump inlet, and the negative impellers are arranged on a rotor shaft on the side connected with the motor; blades on the positive impellers are bent in the clockwise direction, and blades on the negative impellers are bent in the anticlockwise direction; suction ports of the positive impellers correspond to the inlet of the pump; and suction ports of the negative impellers correspond to the motor. When the multi-stage shielded electric pump is used, the axial forces acting on the positive impellers and the negative impellers are approximate equal and in opposite directions, and thus the axial forces can be greatly reduced. The pressure distribution of the impellers at each stage behind the impeller to be cut can be improved through cutting the outside diameter of the impeller to be cut, and the effect of balancing the residual axial force can be achieved. By adopting the structure, the whole structure of the pump is more compact.

Description

technical field [0001] The invention belongs to the technical field of canned electric pumps, in particular to a multi-stage canned electric pump equipped with even-numbered impellers. Background technique [0002] Axial force is an important research topic in the field of canned electric pumps. The imbalance of axial force will lead to serious consequences such as increased bearing wear, which will affect the normal operation of the pump. When the pump is in operation, an axial force acts on the rotor, which will pull the rotor to move axially. Therefore, it is necessary to try to eliminate or balance this axial force in order to make the pump work normally. The axial force acting on the pump rotor is mainly composed of the following components: 1. The axial force generated by the asymmetry of the front and rear cover plates of the impeller, This force points to the direction of the impeller suction port, represented by A1; 2. Dynamic reaction force, this force points to t...

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