Recommended practical methods for selecting NBR seals
① In the selection of NBR seals, the working conditions must be considered, so as to select the appropriate seal form, sealing material, and installation structure.
②The working conditions that need to be considered in the selection of 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.
③ Regarding temperature, the working temperature range of sealing material NBR material is generally -40～+120℃. If it exceeds 120℃, consider using FKM, even PTFE materials. Low temperature conditions are relatively rare. Generally speaking, cold-resistant NBR should be considered at -20～-40℃, while general NBR materials will be used in low temperature environments. It will cause the material to harden and lead to leakage. For example, railway locomotives often have such problems in the winter in the north.
④ As for pressure, it affects the form of NBR seals to be selected. Generally speaking, the use of rubber or PU seals for low pressure and medium pressure will not cause much problem. However, an impact pressure must be considered. For example, when starting in construction machinery, its impact pressure is much greater than the normal working pressure when it is closed. PTFE composite seal is also a commonly used choice.
⑤The problem of medium is relatively simple. Just need to pay attention to some special minor issues, such as the metallurgical industry's cylinders 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 using the latter hydraulic oil, you still need to choose FKM.
⑥The selection of NBR seals is very important, and it must be selected in accordance with the equipment itself.
