Cryogenic valve common faults and troubleshooting

No.

malfunction

the reason

Approach

Valve leakage

1. The valve top and the valve seat sealing surface are indented by hard objects ( such as silicone, metal shavings, welding slag and other hard objects ) to form dents.

2. Valve stem centerline is not perpendicular to valve seat sealing surface ( valve surface )

3. The valve top and valve surface wear out due to long-term use

4. Cracks on both ends of the stem outer thread

1. Repair or replace by grinding or grinding after turning

2. Reassemble or replace

3. Repair or replace by grinding or grinding after turning

4. Pull out the stem, refill tin, tighten, and preferably use silver welding

Valve packing running frozen junction

1. When the packing is uneven, not tight, or the stem is not straight or round, the cryogenic liquid or gas leaks along the gap at the packing. Because of the cold transmission, the moisture in the air freezes on the packing and freezes the valve stem.

1. Use steam or hot water to heat the packing to open and close the valve 2. After overhauling the valve, the packing should be evenly packed and tightly tightened to tighten the compression nut.

Flange leaked

1. The sealing surface is not smooth and uneven

2 bolts are not evenly tightened

3. Improper bolt material

1. Repair or replace by grinding or grinding after lathing, replace the gasket

2. The bolt is tightened evenly

3. Replace the bolt