1. Valve packing leakage.

Cause analysis:

1. The packing gland is not tightly pressed.

2. The filling material may become ineffective due to prolonged use or improper storage.

Solution:

1. Tighten the nut evenly and tighten the packing tightly.

2. Replace the packing.

2. Leakage between sealing surfaces.

Cause analysis:

1. There are dirt and debris adhering to the sealing surface.

2. The sealing surface is damaged.

Solution:

1. Clean up the dirt and debris.

2. Reprocess, repair or replace.

3. Leakage at the connection between the valve body and the valve cover.

Cause analysis:

1. The connecting bolts are not tightened evenly.

2. The flange sealing surface is damaged.

3. Gasket rupture or failure.

Solution:

1. Tighten evenly.

2. Repaired.

3. Replace the gasket with a new one.