What is the difference between a self-balancing multistage centrifugal pump and an ordinary multistage pump?

Self-balancing multistage centrifugal pumps and ordinary multistage centrifugal pumps can be used under the same operating conditions, but it is not clear how much difference there is between the two. The following will compare the differences between self-balancing multistage pumps and ordinary multistage centrifugal pumps from many aspects.

• Structural comparison

The impellers of the traditional D-type horizontal multistage centrifugal pump are arranged in the same direction. The axial force on each impeller is in the same direction. In order to balance the axial force, a special balancing mechanism is set up, which includes a balancing disc, a balancing ring (balancing ring sleeve), and a balancing pipe.

Self-balancing multistage centrifugal pumps use symmetrically arranged impellers to achieve automatic balancing of axial forces by offsetting the positive and negative impellers, without the need for traditional balancing discs or balancing drums. This design eliminates the wear and failure problems of the balancing device and improves the reliability and service life of the pump. In contrast, ordinary multistage centrifugal pumps usually use balancing discs and balancing rings to balance the axial force, but the balancing discs are prone to wear, resulting in reduced efficiency and increased maintenance costs.

Ordinary multistage pump

• Performance comparison

Since there is no friction loss and reflux loss of the balancing device, the operating efficiency of most models of self-balancing multistage centrifugal pumps is usually about 2% higher than that of ordinary multistage centrifugal pumps. In addition, the design of the self-balancing pump reduces volume loss, improves overall operating efficiency, and reduces shaft power. Self-balancing multistage centrifugal pumps can also maintain stable flow and pressure under high load and high pressure environments, thereby ensuring efficient and stable operation.

• Efficiency comparison

Ordinary multistage pump: Due to the backflow of the balance return pipe, the volume loss is large. Especially when the balance parts are worn, the impeller outlet center deviates from the guide vane inlet center, which further reduces the efficiency of the pump.
Self-balancing multistage pump: The hydraulic performance and structural design have been fully optimized to improve the efficiency of the pump.
The balance return pipe structure that ordinary multistage pumps must have is not required, which further improves the volumetric efficiency of the pump. The impeller and guide vane are always in a centered state, which will not affect the efficiency of the pump.

• Overall Advantages

High efficiency and energy saving: We adopt advanced hydraulic models and independently develop high efficiency and energy-saving products. Since the pump rotor is free from the wear and axial movement of the balancing disc, the concentricity of the impeller and the guide vane is always in the best state, unlike the ordinary multi-stage pump structure, which will not show a significant decrease in efficiency due to the wear of the balancing disc and the forward movement of the rotor parts. There is no leakage of balancing water, which reduces the volume loss, improves the overall operation efficiency of the pump, reduces the shaft power, and has a good energy-saving effect.

High reliability: The symmetrical arrangement of the impeller allows the axial thrust generated during operation to be basically automatically balanced, thus eliminating the need for a balance plate device with small clearance, high pressure drop, easy erosion, easy wear, and easy failure, so that the axial thrust due to the axial force is not required. Wear and adverse effects on system disturbances caused by loads are minimized. The residual axial force is borne by the thrust bearing, so that the pump shaft is always in a state of tension, the stress state of the shaft is uniform, and the stress peak is greatly reduced compared with the prototype structure, thereby improving the rigidity and critical speed of the pump rotor, making the pump rotor run The stability and reliability are significantly improved.

Low maintenance cost: precision casting is used to reduce the number of vulnerable parts, reduce the number of times of assembly and disassembly to replace vulnerable parts, extend the product life, and avoid a series of problems caused by excessive assembly and disassembly to the greatest extent. Pump vibration and noise are greatly reduced, and maintenance costs are greatly reduced.