How to Prevent the Flange Seal from Losing Efficacy at High Temperatures?

How to prevent the flange seal from losing efficacy at high temperatures? Here are some suggestions listed as follows.
 

1. Set the insulation lining or ring on the inside of the gasket and the flange to change the heat condition of the flange, the bolt as well as the gasket, to reduce the temperature and the temperature difference among them, and to avoid the yielding and creeping of the bolt as well as the deformation of the flange.

2. Use the lap joint flange which has better resistance to the thermal shock and the thermal cycling load.

3. Use the sleeve to extend the length of the bolt. The total length of the bolt and the sleeve can compensate for the thermal stress. It allows the flange to have a greater axial thermal expansion displacement, and the bolt's stress not to reach the yield limit. Thus it plays an important role in proventing the overload of the gasket.

4. Add the elastic gasket to the bolt. The elastic gasket will expand when it absorbs water, but its stiffness is much smaller than the stiffness of the sleeve, which makes the elastic gasket unable to afford too much gasket preload, easy to be flattened, and unsuitable for high pressure conditions. The operating temperature of the elastic gasket should not be too high in order to avoid its loss of elasticity caused by temper.

5. Avoid the occurrence of the temperature difference on the flange, especially the flange with the longitudinal partition. Lay the insulation lining or the water leg on the high temperature side of the flange to make the circumferential temperatures approach each other.

6. The material of the gasket should be selected according to the temperature and pressure.

7. Try to reduce the temperature difference between the cylinder and the flange to prevent the fatigue of the gasket, the loosing of the bolt and the further leakage resulted from the increased preload of the gasket.