What problems should be paid attention to in the selection of rubber seals

In the selection of rubber seals, the working conditions must be considered, so as to select the appropriate seal form, sealing material and installation structure.

The working conditions that need to be considered in the selection of rubber seals generally include: temperature, pressure, and medium. Others also need to consider the selection of seals in combination with the characteristics of the equipment itself.

Regarding the temperature, for example, the working temperature range of the sealing material NBR material is generally -40 to +120 °C. If it exceeds 120°C, it is necessary to consider using FKM, or even PTFE materials. The low temperature is relatively rare. Generally speaking, cold-resistant NBR should be considered when the temperature is -20 to -40°C. The general NBR material is used in a low temperature environment. It will cause the material to harden and cause leakage, such as railway locomotives that often occur in the winter in the north.

As for pressure, it affects the form of seal to be selected. Generally speaking, the use of rubber or PU seals for low pressure and medium pressure will not be a big problem. However, there is a problem of impact pressure to consider. For example, when the construction machinery is started, its impact pressure is much greater than the normal working pressure when it is closed. Therefore, HBY or SPGW with a pressure resistance of up to 70MPA and impact resistance and anti-squeeze gap are often selected. seal. PTFE combination seals are also a commonly used option.

The question of media is simpler. Just need to pay attention to some special small problems, such as the hydraulic cylinders of the metallurgical industry often use water-glycol and phosphate ester hydraulic oil. Sometimes, although the working temperature is not high, you still need to be very careful when choosing the sealing material. When the hydraulic oil uses the latter, you still need to use FKM.

The selection of seals is very important, and it must be selected according to the situation of the equipment itself.