Application selection of check valves in different fluid media

Selection of check valves in clean fluids
For clean fluids, the selection of check valves is relatively broad, because such fluids usually do not cause clogging or excessive wear of the valves. Swing check valves and lift check valves are the two most common types, which are widely used in various clean fluid systems.

Swing check valves are known for their unique valve disc design, which can rotate freely around the hinge. When the fluid flows forward, the valve disc is pushed open, allowing the fluid to pass smoothly; once the fluid stops flowing or flows in the reverse direction, the valve disc quickly closes due to gravity or fluid pressure difference, effectively preventing the medium from flowing back. The advantages of this valve are small fluid resistance and flexible opening and closing movements, which are suitable for large-diameter, high-flow clean fluid pipelines.

Lift check valves control the flow of fluid by moving the valve disc up and down. When the fluid pressure is sufficient to overcome the weight of the valve disc and the resistance of the spring, the valve disc rises and the fluid passes; conversely, the valve disc drops to close the channel. The lift check valve has a relatively simple structure and good sealing performance. It is especially suitable for clean fluid systems with high sealing requirements, such as liquid transmission lines in the food processing and pharmaceutical industries.

Check valve selection in media containing solid particles or high viscosity
When facing media containing solid particles or high viscosity, the selection of check valves needs to be more cautious to avoid problems such as clogging, wear and sealing failure. Ball check valves and diaphragm check valves are the first choice for such media due to their special design.

The ball check valve performs well in fluids containing solid particles with its unique ball valve disc design. The ball valve disc can rotate freely and close to the valve seat under the action of fluid power to achieve effective sealing. At the same time, due to the smooth surface of the ball, it is not easy to accumulate particles, reducing the risk of clogging. In addition, the ball check valve usually has a large flow area, which reduces the resistance when the fluid passes through, and is suitable for the transmission of high-viscosity media, such as paint, resin, etc.

The diaphragm check valve, with its diaphragm flexibility, shows unique advantages in handling pipelines containing solid particles, especially those prone to water hammer. As a valve disc, the diaphragm can completely isolate the fluid from mechanical parts such as the valve stem, effectively preventing particles from wearing the valve. When the fluid flows forward, the diaphragm is compressed and deformed to open; when the fluid stops or flows in the reverse direction, the diaphragm quickly resets and closes by its own elasticity or spring force. This design not only improves the durability of the valve, but also greatly reduces the system damage caused by water hammer. It is widely used in industries such as sewage treatment and chemical processes.

The selection of check valves needs to be considered comprehensively according to the characteristics of the fluid medium. For clean fluids, swing and lift check valves are preferred due to their low resistance and good sealing performance; when dealing with media containing solid particles or high viscosity, ball check valves and diaphragm check valves rely on their unique structure and adaptability to ensure the stable operation of the system. Correct selection and application of check valves can not only improve fluid transmission efficiency, but also effectively extend the life of the equipment and ensure the safety and reliability of the entire production process. Therefore, in practical applications, reasonable selection should be made according to the specific working conditions and the characteristics of various check valves to achieve the best fluid control effect.