Valve Disc-Related Failures
A common issue with check valves is damage to the valve disc, especially when there is a large flow of medium or when the pressure on both sides is nearly balanced. In such cases, the valve disc frequently collides with the valve seat, causing damage. If the valve disc material is inappropriate, such as using brittle materials (like cast iron or brass), the likelihood of such failures increases.
Solution:
Choose high-strength, wear-resistant materials (such as stainless steel or alloys). Regularly inspect the valve disc, avoid using media with high viscosity or containing particulate matter, and ensure proper installation and adjustment to prevent excessive gaps between the valve disc and valve seat.
Another common failure is the inability of the valve disc to move smoothly, often due to the gap between the valve disc and guide sleeve being too small, or excessive friction between the valve stem and guide sleeve. When used for long periods with fluids containing impurities or high viscosity, the valve disc may become worn or blocked, causing difficulty in movement.
Solution:
Keep the valve body clean, avoid excessive impurities in the medium, perform regular cleaning and maintenance, and ensure the flexibility of the valve disc. Especially during installation, ensure that the gaps between components comply with specifications.
Backflow Failure
Backflow is one of the most common failure types in non return valves, usually caused by damage, aging, or blockage of the sealing surface. When the sealing surface is worn or fails to form a tight seal, it cannot effectively prevent reverse flow of the medium, resulting in backflow.
Solutions:
• For media containing high levels of impurities, it is recommended to install a filter before the valve and regularly clean the valve to prevent debris from entering the valve interior.
Rocker Mechanism Failure
In swing check valves, failure of the rocker mechanism is a relatively common issue. When the upstream and downstream pressures are nearly balanced, the valve disc may frequently strike the valve seat, causing damage to the rocker and other components. Additionally, looseness or wear at the connections between the rocker, valve disc, and spindle, as well as deformation or breakage of the rocker, can also lead to such failures.
Solutions:
• Ensure correct assembly of the rocker to prevent frequent collisions between the valve disc and valve seat caused by unstable pressure.
• Regularly inspect the rocker mechanism, making sure all connections are tight; repair or replace any loose or worn parts promptly.
• Under operating conditions with significant pressure fluctuations, it is recommended to use cast steel valve discs and steel rockers to enhance durability.
Regular Inspection and Maintenance RecommendationsTo minimize check valve failures, it is recommended to perform regular maintenance and inspections:
• Inspect sealing surfaces: Regularly check the wear condition of the sealing surfaces and valve seats to ensure they remain intact and undamaged.
• Clean debris: When handling media containing particulates or viscous fluids, clean the valve interior periodically to prevent debris from clogging the valve disc and rocker.
• Adjust the valve disc: Ensure smooth movement of the valve disc to avoid failures caused by sticking or jamming.
• Select appropriate materials: Choose valve materials suited to specific operating conditions to enhance durability and corrosion resistance.
Conclusion
Check valves are critical components in piping systems. Proper installation, correct selection, and regular maintenance can significantly extend their service life and prevent common failures. By understanding and addressing typical check valve issues, you can ensure efficient and stable system operation. If you have any questions regarding selection or maintenance, feel free to contact our professional team for support.
