Reasons for Leakage of Valve Packing
1. The packing is not suitable for use in high pressure or vacuum, high temperature or low temperature.
2. Installation of packing is not correct. There are some defects, such as replacing small size with large size, bad spiral winding joint, tightening up and loosening down.
3. The filler has aged and lost elasticity after its service life.
4. The accuracy of the valve stem is not high and there are some defects such as bending, corrosion and wear.
5. The number of packing rings is insufficient and the cap is not pressed.
6. The cover, bolt and other parts are damaged, so that the cover can not be pressed.
7. Improper operation and excessive exertion, etc.
8. The cover is skewed and the gap between the cover and the stem is too small or too large, which results in the wear of the stem and the damage of the packing.
Prevention and exclusion methods:
1. Material and type of filler should be selected according to working conditions.
2. According to the relevant regulations, the packing should be installed and compacted one by one, and the joint should be 30 or 45 degrees Celsius.
3. Fillers with long service life, aging and damage should be replaced in time.
4. The valve stem should be straightened and repaired after bending and wearing, and the damaged valve stem should be replaced in time.
5. Packing shall be installed in accordance with the prescribed number of loops, the cover shall be tightened symmetrically and evenly, and the jacket shall have a pre-tightening clearance of more than 5 mm.
6. Damaged caps, bolts and other parts should be repaired or replaced in time.
7. Operating rules should be obeyed. Except for impact handwheel, it should be operated with normal force at uniform speed.
8. The cover bolt should be tightened evenly and symmetrically. If the gap between the cover and the stem is too small, the gap between the cover and the stem should be increased appropriately. If the gap between the cover and the stem is too large, it should be replaced.
