How does multistage centrifugal pump balance axial force

The chemical pump balances the axial force through the combination of balance disc and balance drum. The balance disc has axial clearance, and the balance chamber is connected with the inlet by pipeline.

When the rotor of the multi-stage centrifugal pump moves to the inlet end, the axial clearance of the balance disc decreases, the radial clearance of the balance drum remains unchanged, and the chamber pressure between the balance drum and the balance disc increases to balance the increased axial force. This structure overcomes the shortcomings of the balance disc, has small leakage and can automatically balance the axial force.

The thrust bearing is installed behind the radial bearing at the outlet end. It can bear axial forces in two directions, and it can fix the rotor at a certain position. This bearing can bear the additional force or residual axial force generated by the operation of the pump under various abnormal working conditions.

Thrust bearing, for small pumps with small axial force, it is usually a simple and economical method to use thrust bearing to bear axial force. Even if other balancing devices are used, thrust bearings are sometimes installed in consideration of the total residual axial force.

A balance pipe is installed on the pump body of the multi-stage centrifugal pump, and the high-pressure end near the wheel Yi outside the impeller disc is connected with the suction end of the centrifugal pump with a pipe to basically balance the pressure on both sides of the impeller, so as to eliminate the axial force. The advantages and disadvantages of this method are similar to those of the balanced hole method. Some centrifugal pumps are equipped with balance pipe and balance hole at the same time, which can get better balance effect

Double suction impeller is adopted, which makes use of the structural characteristics of the impeller to achieve its own balance. Since the two sides of the double suction impeller are symmetrical, there will be no axial force in theory, but due to the manufacturing quality and the difference of liquid flow on both sides of the impeller, it is impossible to balance all the axial force

Radial rib plate is set on the impeller, and radial rib plate is set outside the impeller disc to balance the axial force. After setting the radial rib plate, the liquid in the high-pressure side of the impeller is driven by the radial rib plate to rotate at a speed close to the rotation speed of the impeller. Under the action of centrifugal force, the liquid pressure in the cavity is reduced, so as to balance the axial force on both sides of the impeller
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