Common Faults and Precautions in Cryogenic Valve Operation

 
Cryogenic valves are designed for use in extremely low-temperature environments, typically ranging from -40 degrees Celsius to -196 degrees Celsius. However, like any other valves, cryogenic valves are prone to various malfunctions. Here, we will explore common types of failures associated with cryogenic valves and precautions to be taken during their usage.
 
Common Failures of Cryogenic Valves
 
As critical equipment operated in extremely low-temperature environments, cryogenic valves may encounter various malfunctions during usage. Below are common types of failures associated with cryogenic valves:
 

• Packing Failure: Valve stem packing is usually located in the packing groove adjacent to the valve stem against the cold box wall. If the packing is uneven, loose, not circular, or if the valve stem is not straight, cryogenic liquids or gases may leak outside through the gaps in the packing. In such cases, the packing may freeze, and the valve stem may be frozen, requiring steam or hot water heating of the packing to operate the cryogenic valve.
• Flange Leakage: Flange leakage is mainly caused by uneven sealing surfaces, inadequate pipeline compensation, uneven tightening of bolts, or improper bolt material.

Precautions for Using Cryogenic Valves
 
When using cryogenic valves, special attention must be paid to the following points to ensure their normal operation, prolong their lifespan, and ensure the safety of operators and equipment:
 

• Friction Damage Reduction: Since the working environment temperature is extremely low, lubricating oil cannot be applied to the valve components, so measures must be taken to reduce friction damage.

• Heat Dissipation Prevention: Cryogenic valves should not become heat sources, as this could cause cryogenic media vaporization, resulting in abnormal pressure and potential hazards. Adequate preparation must be made during operation.

• Choosing Fire-resistant Materials: Due to the flammable and explosive nature of cryogenic media, fire-resistant materials must be used in parts that come into contact with cryogenic valves.

• Ensuring Quality: When selecting cryogenic valves, ensure their quality, as they operate in cryogenic environments for extended periods and need to have long-life characteristics.

 
In conclusion, understanding the common failures and precautions for using cryogenic valves is crucial to ensure their proper functioning. Only by following the correct operating procedures and precautions can cryogenic valves perform effectively.