1, select Precautions
The correct selection of gasket is the key to ensure no leakage devices. For the same conditions, generally several pads to choose from. Must be based on media properties, pressure, temperature and device size, operating conditions, continuous operation cycle length of Deng situation, rational selection of gaskets, avoid weaknesses, give full effect to the characteristics of pads.
Select gasket should fully consider the following factors:
(1) have good flexibility and resilience, able to adapt to changes in pressure and temperature fluctuations;
(2) the proper flexibility, able to interface well with the fit;
(3) not pollute the process medium;
(4) have sufficient toughness and not caused by stress and fixing broken power ring;
(5) low temperature without hardening, shrinking a small amount;
(6) processing performance, installation, compaction convenient;
(7) does not bond the sealing surface, removal is easy;
(8) cheap, long service life.
The use of the gasket, the pressure and temperature and they are mutually conditioned, with the temperature in the equipment operation some time after the occurrence of gasket material softening, creep, stress relaxation, mechanical strength will decrease reduce the pressure seal. And vice versa. For example, the manual lists high-pressure asbestos rubber sheet XB450 water, steam medium, temperature 450 ℃, pressure <6MPa (the material used in the sealing performance test in 440 ℃ ~ 450 ℃, 12MPa pressure steam Bulgaria 30 minutes) . But in the long term practical use, if the temperature reached 450 ℃, can seal the pressure only 0.3 ~ 0.4MPa. The permeability of gas medium is strong only 0.1 ~ 0.2MPa.
Above, should be fully considered in the selection.
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