1. Internal Leakage

① At low temperatures, the fitting degree of seat ring and disc ring get poor due to inconsistent shrinkage of the valve stem and plate.

② To achieve a good sealing under high-temperature conditions, the closing torque of the actuator is excessively large, resulting in high pressure on sealing surface. The higher the pressure on the sealing surface, the higher the possibility of wear, creep, overload, and metal adhesion. It increases the probability of damage on the sealing surface and the iinternal leakage.

③ Excessive locking force on the seal ring retainer prevents the seal ring from achieving its self adaptive adjustment.

2. External Leakage

An unreasonable extension height of the valve bonnet may easily cause condensed water in the air to enter the packing, where it freezes, scratches the packing, and leads to external leakage.

3. Valve Jamming

At low temperatures, residual moisture inside the valve freezes, causing a sharp increase in valve torque, reaulting jamming of the valve.