Causes of leakage at valve packing:
1. The packing is incorrectly selected and is not resistant to the corrosion of the medium and the valve is not resistant to high pressure or vacuum, high temperature or low temperature;
2. The packing is installed incorrectly, with defects such as replacing large ones with small ones, poor spiral coiled joints, and tightening and loosening.
3. The filler has expired, has aged, and lost elasticity.
4. The valve stem has low accuracy and has defects such as bending, corrosion, and wear.
5. The number of packing rings is insufficient and the gland is not pressed tightly;
6. The gland, bolts, and other parts are damaged, making it impossible to tighten the gland;
7. Improper operation, excessive force, etc.;
8. The gland is skewed, and the gap between the gland and the valve stem is too small or too large, causing the valve stem to wear and the packing to be damaged.

Prevention and elimination methods:
1. The material and type of filler should be selected according to the working conditions;
2. Install the packing correctly according to relevant regulations. The packing should be placed and tightened one by one, and the joints should be at 30°C or 45°C;
3. Packing that has been used for too long, is aged, or is damaged should be replaced in time;
4. If the valve stem is bent or worn, it should be straightened and repaired. If the valve stem is seriously damaged, it should be replaced in time;
5. The packing should be installed according to the specified number of turns, the gland should be tightened symmetrically and evenly, and the gland should have a pre-tightening gap of more than 5mm;
6. Damaged glands, bolts and other parts should be repaired or replaced in time;
7. The operating procedures should be followed. Except for the impact handwheel, operate it with normal speed and force;
8. The gland bolts should be tightened evenly and symmetrically. If the gap between the gland and the valve stem is too small, the gap should be appropriately increased; if the gap between the gland and the valve stem is too large, it should be replaced.