Note on the selection process of the seals

1. For the selection of seals, the working conditions must be considered to select the appropriate seal form and sealing material and installation structure.

2, the selection of the seal needs to consider the working conditions generally include: temperature, pressure, medium. Others also need to consider the selection of the seal in combination with the characteristics of the device itself.

3, on the temperature, such as sealing material NBR material operating temperature range is generally -40 ~ +120 °C. If it exceeds 120 °C, it is necessary to consider FKM, even PTFE material. Low temperature is rare. Generally speaking, cold-resistant NBR should be considered in the case of -20~-40°C. In general, NBR materials will cause the material to harden and lead to leakage, such as the winter of railway locomotives in the north. This type of problem often occurs.

4. As for the pressure, it affects the form of the seal to be used. In general, low pressure medium pressure is not a big problem with rubber or PU seals. However, it is necessary to consider a problem of impact pressure, such as starting in a construction machine. When it is closed, its impact pressure is much larger than the normal working pressure, so it is often used as an anti-impact anti-extrusion HBY or SPGW with a pressure resistance up to 70MPA. seal. PTFE combination seals are also a common choice.

5, the problem of the media is relatively simple. Just need to pay attention to some special small problems, such as the metallurgical industry's cylinders often use water-glycol and phosphate ester hydraulic oil. Sometimes, although the working temperature is not high, it is very important to choose the sealing material. When using the latter, the hydraulic oil should use FKM.

6, the selection of seals is very important, or must be selected in conjunction with the equipment itself.

7. Cylinders, compressor piston rings, high pressure oil seals, and oil pumps in various scientific instruments. Their seals require special construction to meet the requirements.