What are the common faults of cryogenic valves?

Cryogenic valves operate under low temperature conditions. Common faults mainly include:

1. Seal failure

(1) Leakage at the packing

Cause: packing aging, corrosion, uneven filling, and valve stem wear.

Performance: Leakage between the valve stem and the stuffing box.

(2) Seat seal leakage

Cause: Sealing surface damage, sealing material hardening and loss of elasticity at low temperature, and the valve is not closed tightly.

Performance: The medium still leaks after the valve is closed.

2. Failure of operation

(1) Valve core stuck or frozen

Cause: Water in the medium freezes at low temperature, impurities are deposited, and lubrication is poor.

Performance: The valve cannot be opened or closed normally.

(2) Transmission component failure

Cause: Low temperature causes changes in material properties, deformation and damage of transmission components.

Performance: Handwheels, gear boxes, etc. are not flexible or fail to operate.

3. Structural damage

(1) Cracks in valve body and valve cover

Cause: Increased low temperature brittleness of materials and cracking caused by thermal stress.

Symptoms: Cracks in the valve body or valve cover lead to leakage.

(2) Leakage at the connection

Cause: Damage to the flange sealing surface, loose bolts, and failure of the sealing gasket.

Symptoms: Leakage at the flange connection or threaded connection.

4. Blockage

Blockage of the internal channel

Cause: Deposition of impurities and crystals in the medium, and complex internal structure of the valve.

Symptoms: Reduced or inability to pass the fluid flow.

5. Noise and vibration

Cause: Changes in material properties at low temperatures, loose valve internal structure, and unstable fluid flow.

Symptoms: Abnormal noise and vibration during valve operation.

Preventive measures

1. Select suitable materials and structures

Select low-temperature and corrosion-resistant materials such as austenitic stainless steel. Use specially designed low-temperature valve structures to prevent cold bridge effects.

2. Regular maintenance and care

Regularly check the sealing performance, transmission components, and connection parts of the valve. Replace aging or damaged seals and packings in a timely manner.

3. Strengthen lubrication and antifreeze measures

Use low-temperature grease to keep the valve flexible. Take insulation or heating measures to prevent ice from forming inside the valve.

4. Correct installation and operation

Install strictly in accordance with the specifications to ensure reliable sealing of the connection parts. Avoid frequent switching and excessive force on the valve.

By understanding the common failures of low-temperature valves and their causes, and taking effective preventive and maintenance measures, you can ensure the reliable operation of the valve under low-temperature conditions, and ensure production safety and system stability.