What are the common failures of check valves and their solutions?

1. The valve is stuck or cannot be completely closed
cause of issue:
During use of the check valve, the valve may become stuck or fail to close completely. This is usually due to foreign matter or impurities inside the valve, such as rust, welding slag or other debris in the pipe. These foreign objects may hinder the free movement of the valve disc, causing the valve to fail to close properly. Wear or damage to the valve disc or seat can also cause this problem. During long-term use, the surfaces of the valve disc and valve seat may be eroded and corroded by the fluid, thereby losing their sealing function. Another situation is incorrect installation. If the valve is tilted during installation, the valve disc may not be aligned with the valve seat, thus affecting the closing effect.
Solution:
Disassemble the valve and check for foreign matter inside. Clean the impurities inside the valve and ensure that the valve disc can move freely. If the valve disc or valve seat is found to be worn or damaged, it is recommended to replace the corresponding parts to restore sealing performance. Recheck that the valve is installed correctly, making sure the valve is aligned with the pipe and avoid tilted installation. Proper installation ensures that the valve disc is accurately aligned with the valve seat for effective closing.

2. Valve leakage
cause of issue:
Check valve leakage is a common problem, usually caused by damage to the sealing surface. The sealing surface may be corroded, worn or scratched due to long-term use, thus losing its sealing ability. Another reason is the aging or damage of the sealing gasket. Especially in high temperature, high pressure or corrosive environments, the gasket material may gradually lose elasticity and sealing performance. In addition, if the seal is not tight during installation, the valve will also have leakage problems.
Solution:
To solve the problem of check valve leakage, you first need to inspect the sealing surface. If the sealing surface is found to be damaged, it should be repaired or replaced. For example, minor scratches on the valve disc or seat can be repaired by grinding, while severe damage will require replacement parts. Replace aging or damaged gaskets and choose gasket materials that are durable and suitable for the working environment. Make sure the valve is installed correctly and seals well. During the installation process, the bolts should be tightened with appropriate torque to ensure that the sealing gasket is evenly stressed and prevent leakage.

3. Valve vibration or noise
cause of issue:
Check valves that vibrate or make noise are usually due to water hammer caused by excessive flow rates. The water hammer effect is a pressure wave generated when the fluid suddenly stops or changes direction, which may impact the valve, causing vibration and noise. In addition, if the valve size is improperly selected, such as too large or too small, it may also lead to unstable fluid flow and vibration. The vibration of the valve disc during fluid flow is also a common cause, especially in high-speed fluids, the valve disc may open and close frequently, causing vibration and noise.
Solution:
In order to solve the vibration and noise problems of the check valve, the flow rate needs to be adjusted first to avoid the occurrence of water hammer. This can be achieved by adjusting the operating parameters of the pump or installing a buffer device. It is important to select an appropriately sized valve to ensure that the valve operates within the design flow rate range, thereby reducing vibration and noise. If the valve vibrates severely, you can consider installing anti-vibration measures, such as adding supports or using elastic gaskets, to reduce the impact of vibration on the piping system.

4. The valve moves slowly
cause of issue:
Sluggish check valve operation may be caused by poor lubrication of the valve shaft or valve stem. During the long-term operation of the valve, the lubricating oil may dry out or fail, causing increased friction on the valve shaft or valve stem, resulting in slow action. Another reason is spring fatigue or damage. The spring may lose elasticity or break during long-term use, affecting the rapid opening and closing of the valve. Insufficient system pressure will also cause the valve to act sluggishly, because the valve requires a certain amount of pressure to overcome the spring force for normal operation.
Solution:
To solve the problem of slow valve action, you can start from the following aspects. Lubricate the valve shaft and valve stem regularly to ensure that their moving parts remain well lubricated and reduce friction resistance. Secondly, check the condition of the spring. If the spring is found to be fatigued or damaged, it should be replaced in time. Check the system fluid pressure to make sure it is within design limits. If the pressure is insufficient, you may need to a

djust the pump's operating parameters or check the piping system for blockages.

5. The valve cannot be opened
cause of issue:
A check valve that won't open is usually caused by a stuck or broken spring. The main function of the spring is to help the valve disc close quickly. If the spring is stuck or broken, the valve disc may not open normally. In addition, it is also a common cause that the valve disc is stuck by foreign objects. Impurities in the pipeline may hinder the free movement of the valve disc. Another reason is that there is insufficient pressure in the system to provide enough force to push the valve open.
Solution:
To solve the problem of a valve that won't open, you need to check the condition of the spring. If the spring is found to be stuck, it can be solved by cleaning and lubricating it. If the spring is broken, it needs to be replaced with a new spring. Secondly, clean the foreign matter inside the valve to ensure that the valve disc can move freely. Check the system pressure to make sure it is high enough to push the valve open. If the system pressure is insufficient, it can be increased by adjusting the operating parameters of the pump or clearing blockages in the piping system.

6. Valve backflow
cause of issue:
Check valve backflow means that fluid can still flow backward after the valve is closed. This is usually caused by a valve that doesn't close tightly. Loose closing of the valve may be due to damage to the sealing surface, wear of the valve disc or valve seat, etc. In addition, backflow problems can also occur if the valve is improperly designed or selected, such as if the valve is selected so that it cannot fully close under operating conditions.
Solution:
Solving backflow problems requires checking the valve seal. Check the sealing surfaces of the valve disc and valve seat. If wear or damage is found, repair or replace it. Minor wear and tear on the sealing surface can be repaired by grinding, while severe damage will require component replacement. Make sure the valve you choose is suitable for the current operating conditions and that it can fully close within the design range. If the backflow problem is severe, consider installing dual check valves to improve the safety and reliability of the system.

7. Valve life is short
cause of issue:
The short service life of check valves is usually caused by harsh environmental conditions. For example, high temperature, high pressure or corrosive fluids will accelerate the aging and damage of valves. Valve materials that are not suitable for the current working conditions will also shorten its life. For example, valves made of ordinary materials may fail quickly when used in highly corrosive environments.
Solution:
In order to extend the service life of the check valve, valve materials should be selected that are suitable for the use environment. For example, in high-temperature environments, valves made of high-temperature-resistant materials should be selected; in corrosive fluids, valves made of corrosion-resistant materials should be selected. Regular maintenance is also an important means to extend the life of valves. Regularly checking the working status of the valve, promptly cleaning impurities, lubricating moving parts and replacing damaged parts can effectively extend the service life of the valve.