1. In order to prevent the medium from flowing backwards, a check valve should be installed on the equipment, equipment and pipelines; 2. The check valve is generally suitable for clean media, and should not be used for media containing solid particles and high viscosity; 3. Generally, vertical lift check valves should be used on horizontal pipes with a nominal 50mm pass; 4. The straight-through lifting check valve can be installed on both horizontal and vertical pipes; 5. For the inlet pipe of the water pump, the bottom valve should be selected. The bottom valve is generally installed only on the vertical pipe of the pump inlet, and the medium flows from bottom to top; 6. The lift type has better sealing performance than the swing type, and the fluid resistance is large. The horizontal type should be installed on the horizontal pipe and installed vertically on the vertical pipe; 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 vertical pipelines, the flow direction of the medium should be from bottom to top; 8. The swing-type check valve should not be made into a small-diameter valve, which can be made into a high working pressure. The PN can reach 42 MPa, and the DN can also be made very large, and the maximum can reach 2000 mm or more. Any working medium and any operating temperature range can be applied depending on the material of the housing and the seal. The medium is water, steam, gas, corrosive medium, oil, medicine, and the like. The working temperature of the medium ranges from -196 to -800 °C; 9. Applicable occasions are low pressure and large diameter, and the installation occasions are limited; 10. The installation position of the butterfly check valve is not limited. It can be installed on the horizontal pipeline or on the vertical or inclined pipeline. 11. Diaphragm check valve is suitable for pipelines that are prone to water hammer. The diaphragm can well eliminate the water hammer generated when the medium is reversed. It is generally used on low pressure normal temperature pipelines, especially for tap water pipelines. The temperature is between -12--120 °C, the working pressure is <1.6 MPa, but the diaphragm type check valve can achieve a larger diameter, and the DN can reach 2000 mm or more; 12, spherical check valve is suitable for medium and low pressure pipelines, can be made into large diameter; 13. The shell material of the spherical check valve can be made of stainless steel. The hollow sphere of the seal can be wrapped with PTFE engineering plastic, so it can also be applied on the pipeline of general corrosive medium. The working temperature is -101--150. Between °C, its nominal pressure is ≤4.0MPa, and the nominal passage range is between 200-1200; 14. For the selection of incompressible fluid check valves, the required closing speed must first be evaluated. The second step is to select the type of check valve that may meet the required closing speed; 15. For the selection of the check valve for the compressible fluid, it can be selected according to a similar method of the non-compressible fluid check valve. If the medium flow range is large, the check valve for the compressible fluid can be used. a deceleration device, if the medium flow is quickly stopped and started continuously, such as the outlet of the compressor, a lift check valve is used; 16, the check valve should determine the size of the response, the valve supplier must provide the data of the selected size, so that you can find the valve size when the valve is fully open at a given flow rate; 17. For high and medium pressure check valves below DN50mm, vertical lift check valves and straight lift check valves should be used; 18. For low-pressure check valves below DN50mm, butterfly check valves, vertical lift check valves and diaphragm check valves should be used; 19. For high and medium pressure check valves with DN greater than 50mm and less than 600mm, rotary check valves should be used; 20. For medium and low pressure check valves with DN greater than 200mm and less than 1200mm, wear-free ball check valves should be used; 21. For low-pressure check valves with DN greater than 50mm and less than 2000mm, Yi chooses butterfly check valve and diaphragm check valve; 22. For pipelines that require less water hammer impact or waterless blow when shutting down, a slow-closed swing-start check valve and a slow-closed butterfly check valve should be used. Linear Comparators,Ic Linear Comparators,Ics Linear Comparators,Integrated Circuits Linear Comparators Shenzhen Kaixuanye Technology Co., Ltd. , https://www.icoilne.com
The selection criteria for the check valve are as follows: