How to deal with the leakage of the shaft seal of the circulating chiller?

How to deal with the leakage of the shaft seal of the circulating chiller?

1.Aging, hardening or expansion of sealing rubber ring

When the rubber ring is installed for the first time, the steel ring is used to clamp the rubber ring on the shaft, which is subject to a large extrusion force and a large deformation at one time.

In addition, if the rubber ring is soaked in oil for a long time, it will become hard and expand, which increases the deformation again.

After the rubber ring is deformed, it is not tightly contacted with the inner and outer shells, causing oil and gas leakage. Of course, the amount of deformation varies with materials. For example, PTFE has less deformation than ordinary rubber, and the sealing reliability can be increased by 30 times.

It is precisely because the rubber ring is easy to deform and cause leakage, so as long as the shaft seal does not leak, it should be removed as little as possible; If the rubber ring is deformed after removal, it shall be replaced.

2.Improper selection and poor quality of lubricating oil.

The quality of lubricating oil also plays an important role in maintaining the sealing performance of the shaft seal device. From the perspective of selecting lubricating oil, the most important thing is that the viscosity of lubricating oil should be appropriate.

If the viscosity is too small, it is not easy to form a normal oil film thickness on the friction surface, and the mechanical seal performance is poor, which is easy to cause leakage. It is worth noting that the viscosity of lubricating oil changes significantly with temperature.

The lower the temperature is, the greater the viscosity is. At this time, the fluidity will be lost. If the temperature continues to drop, solidification will occur again. Generally, the flow point shall be 2~3 ℃ higher than the freezing point.

After long-term use of lubricating oil, the surface tension decreases. In addition, a large amount of water and air are mixed in the oil, which reduces the oil viscosity, causes serious emulsification and oxidation, increases the corrosivity, and deteriorates the oil quality.

At this time, the lubricating oil should be replaced once a year. Whether the lubricating oil needs to be replaced can be judged by its color during operation.

If the color changes from reddish to reddish brown and the transparency becomes dark, it indicates that the oil quality has deteriorated. This is because organic acids, polymers, esters, metal salts and other corrosion products are suspended in the oil.

3.During assembly, the coupling cannot be aligned accurately and other assembly conditions cannot meet the requirements

The LX -25°C ~ +30°C Recirculating Chillers rotor shaft and the motor main shaft are connected by the coupling. The alignment of the coupling depends not only on the machining accuracy, but also on the correct assembly after repair, that is, meeting the required assembly accuracy.

If the assembly is improper, the compressor will generate vibration, which will damage the assembly conditions of the original radial seal and axial seal of the shaft seal to some extent, thus causing leakage of the shaft seal.

The two components connected by the coupling are rigid bodies, so the centerline after assembly and correction should be basically in a straight line. Table 3 shows the allowable deviation of the corrected coupling.