Why is the balance disc of multistage centrifugal pump worn seriously?

Category: Water pump knowledge

2024-05-05

The main reasons for the serious wear of the balance disc of the multi-stage centrifugal pump are large, improper material selection and surface treatment, and improper operating conditions and operation. By selecting materials reasonably, optimizing operating conditions and strengthening maintenance, the wear of the balance disc can be reduced. Improve the service life of the centrifugal pump.

多级离心泵平衡盘磨损严重为什么

Analysis of Common Wear Causes of Balance Disc and Its Solution

1. Multi-stage centrifugal pump balance plate by larger force

A centrifugal pump is a device that converts liquid into kinetic energy. Its working principle is to bring the liquid into the pump body through a high-speed rotating impeller, and generate a strong centrifugal force to press the liquid to the outlet. The balance disc, on the other hand, acts to balance the axial and radial forces of the impeller and therefore needs to withstand extreme pressures from the liquid during pump operation. Under this high pressure, friction and wear are inevitable.

2. Material selection and improper surface treatment

The balance plate is usually made of metal material, such as stainless steel or cast steel. If the hardness of the material is not enough or the surface of the material is not handled properly, it is easy to cause the wear of the balance disc. In addition, if there are solid particles or corrosive media in the liquid, these factors will also accelerate the wear of the balance plate.

3. Operating conditions and improper operation

The operating conditions and operating methods of the centrifugal pump also have a certain impact on the wear of the balance disc. For example, improper selection of the working point of the pump, excessive vibration, and unreasonable liquid temperature will accelerate the wear of the balance disc. In addition, the operator's maintenance of the pump is not in place, which will also cause serious wear of the balance plate.

4. Used in frequent opening occasions

Since the balance disc device has the characteristic of friction when opening, this structure is not suitable for frequent opening occasions, only to consider changing the balance mode, replacing other types of pumps or changing the operating conditions of the system.

5. Pressure leaks from behind the balance ring

Since the balance ring and the spitting section are connected by screws, if the tightening is uneven or not tight, the pressure will leak out from here. Due to the leakage of pressure, the balance force is too small, thus causing the balance disc to grind. To check whether the pressure leaks out from here, check whether there are traces of high-pressure water flushing at the junction of the balance ring and the spitting section. If there is, eliminate it and use O-rings to strengthen the seal, in addition, we must pay attention to several fixing screws must be tightened evenly.

6. Gap b1 is too large due to wear of balance sleeve and shaft sleeve

From the previous theory, the gap b1 will be more conducive to pushing away the balance plate, but the leakage will increase and the efficiency will decrease at this time. However, if the opening of b1 is greater than 0.6 from the actual pump operation, the balance plate effect will not be good. It is believed that this is because the leakage is too large after b1 is greater than 0.6, which leads to the balance water pipe not having such a large capacity to lead so much water to the suction inlet, thus causing p6 to rise, and the pressure difference between p6, that is, the balance disc device fails. So make sure b1 is between 0.3 and 0.5.

7. Part shape tolerance is unqualified

Due to the high machining accuracy requirements of the balance plate and balance ring, there is generally no problem. However, unqualified phenomena often occur in the spitting section assembled with the balance ring. Many multi-stage pumps have occurred on site, and they are found to be locked as soon as the pump is turned on. After checking, the balance water pipe is unblocked, and the balance plate and balance ring are also free of problems. The final reason is that the verticality of the spitting section of the balance ring assembly is out, this results in uneven clearance between the balance ring and the balance disc, resulting in failure of the balance device. If the problem is checked out, it is better to replace it.

8. The balance water pipe is blocked

If the balance water pipe is blocked, p6 will be equal to p4, that is to say, the balance plate has failed to produce the balance force and has lost its function. At this time, the axial force of the pump will cause serious friction on the balance plate, the lighter will make the pump unable to run, and the serious point will burn the motor. The blockage of the balance water pipe is the best fault to solve, but it is also the most common, for maintenance personnel, if they encounter a balance device failure, they must first check whether the balance water pipe is unblocked.

In order to reduce the wear of the balance disc of the multi-stage centrifugal pump, we can start from the following aspects. First, choose appropriate materials and carry out good surface treatment to enhance the wear resistance of the balance disc. Second, choose the operating conditions reasonably to avoid excessive Vibration and the entry of solid particles, finally, strengthen maintenance, regularly check and replace the severely worn balance disc to ensure the normal operation of the pump.

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