■Description

The seal has the same flat shape with the groove due to compression on the gap, which makes cracks occur to the seal surface.

■Contributing factors

• Excessive compression

• The design of the seal fails to consider the heat and chemical resistance

• The seal is at the pressure and temperature in high vacuum environment

■Recommended improving method

• The design of seal shall consider the heat and chemical resistance

• Proper force, instead of excessive force, shall be used to install the seal.