How to Install and Select Check Valves?

A brief guid to the installation and selection of check valves.

About how to install and select check valves, you can refer to the following contents, which can give you a quick understanding and a concise operation reference for the installation and selection of check valves:

1. In order to prevent the reverse flow of the medium, check valves should be installed on equipment, devices and pipelines.
2. Check valves are generally suitable for clean media and are not suitable for media containing solid particles and those with high viscosity.
3. Vertical lift check valves should generally be selected for horizontal pipelines with a nominal diameter of 50mm.
4. Straight-through lift check valves can be installed on both horizontal and vertical pipelines.
5. For the inlet pipeline of the water pump, a foot valve is advisable. The foot valve is generally only installed on the vertical pipeline at the pump inlet, and the medium flows from bottom to top.
6. The lift swing check valve has good sealing performance and high fluid resistance. The horizontal type should be installed on the horizontal pipeline, and the vertical type should be installed on the vertical pipeline.
7. The installation position of the swing check valve is not limited. It can be installed on horizontal, vertical or inclined pipelines. If it is installed on a vertical pipeline, the medium should flow from bottom to top.
8. Swing check valves are not suitable for making small-diameter valves, but can be made into valves with very high working pressure. The PN can reach 42MPa, and the DN can also be very large, up to more than 2000mm. Depending on the material of the housing and seals, they can be used for any working medium and any working temperature range. The media include water, steam, gas, corrosive media, oil products, drugs, etc. The working temperature range of the medium is between -196°C and 800°C.
9. The applicable occasion is low pressure and large diameter, and the installation site is limited.
10. The installation position of the butterfly check valve is not limited. It can be installed on horizontal pipelines or vertical or inclined pipelines.
11. The diaphragm check valve is suitable for pipelines where water hammer is likely to occur. The diaphragm can well eliminate the water hammer generated when the medium flows backward. It is generally used on low-pressure and normal-temperature pipelines, especially suitable for tap water pipelines. The general working temperature of the medium is between -12°C and 120°C, and the working pressure is <1.6MPa. However, the diaphragm check valve can be made into a relatively large diameter, and the DN can be up to more than 2000mm.
12. The ball check valve is suitable for medium and low pressure pipelines and can be made into a large diameter.
13. The housing material of the ball check valve can be made of stainless steel, and the hollow sphere of the seal can be wrapped with PTFE engineering plastic, so it can also be applied to pipelines with general corrosive media. The working temperature is between -101°C and 150°C, its nominal pressure is ≤4.0MPa, and the nominal diameter range is between 200 and 1200.
14. For the selection of check valves for incompressible fluids, first evaluate the required closing speed, and then select the type of check valve that may meet the required closing speed.
15. For the selection of check valves for compressible fluids, a similar method to that for incompressible fluids can be used. If the medium flow range is large, a deceleration device can be used for the check valves for compressible fluids. If the medium flow continuously stops and starts quickly, such as at the outlet of a compressor, a lift check valve should be used.
16. The corresponding size of the check valve should be determined, and the valve supplier must provide the data of the selected size, so that the valve size when the valve is fully open at a given flow rate can be found.
17. For high and medium pressure check valves with DN less than 50mm, vertical lift check valves and straight-through lift check valves are advisable.
18. For low-pressure check valves with DN less than 50mm, butterfly check valves, vertical lift check valves and diaphragm check valves are advisable.
19. For high and medium pressure check valves with DN greater than 50mm and less than 600mm, swing check valves are advisable.
20. For medium and low pressure check valves with DN greater than 200mm and less than 1200mm, non-wearing ball check valves are advisable.
21. For low-pressure check valves with DN greater than 50mm and less than 2000mm, butterfly check valves and diaphragm check valves are advisable.
22. For pipelines where the water hammer impact during closing is required to be small or there is no water hammer, slow-closing swing check valves and slow-closing butterfly check valves are advisable.