Mechanical seals at high temperatures

Date:Jan 07, 2020

To ensure that the mechanical seal works normally in a high temperature environment, the following measures can be taken.

  1. Add a cooling and flushing device to the machine seal.

  2. Choose high temperature resistant materials and choose different materials according to different working temperatures. The upper limit of the temperature of nitrile rubber is 80 ° C, the temperature of silicone rubber and fluorine rubber is 200 ° C, and the temperature of polytetrafluoroethylene is 250 ° C. In addition, non-metal friction pairs in mechanical seals are mostly made of graphite impregnated materials, so different types of impregnated graphite should also be selected according to different operating temperatures. Generally, the applicable temperature range of Babbitt graphite is less than 150 ℃, and the applicable temperature range of resin-impregnated graphite is 170 ~ 200 ℃. The graphite impregnated with copper, aluminum and lead can be used under the working conditions of less than 400 ℃. As far as possible, the moving ring assembly should use materials with similar expansion coefficients to prevent the connection between the moving ring and the moving ring seat from becoming loose at high temperatures.

3. Select a metal bellows mechanical seal. Metal bellows seals have been used a lot in high temperature seals in recent years and have achieved very good results. In this kind of mechanical seal, the metal bellows replaces the spring in the ordinary mechanical seal, eliminating the auxiliary ring of the moving ring, and it is not necessary to overcome the friction and wear with the rotating shaft during the compensation of the moving ring. Can achieve good results.

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