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Select mechanical seal
- Aug 13, 2018 -

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

The working conditions to be considered generally include: temperature, pressure, and medium. Others need to be considered in combination with the characteristics of the device itself.


Regarding the temperature, for example, the operating temperature range of the NBR material is generally in the range of -40 to +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.


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.


The problem with 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, the material should be very carefully selected. When the hydraulic oil is used, the FKM should be used.


The selection of the seal is important, and it must be chosen in conjunction with the equipment itself. For example, it needs to be responsive and precise to control, of course, the choice of the Stern Ring. Need high reliability, often choose Hongge's GD1000K series or NOK's SPGW. For example, when working in the field, the construction machinery often has impact and low temperature weather, and its dust ring will use the exposed metal skeleton to avoid falling off.


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