Check valve

The selection criteria for check valves are as follows

1. To prevent backflow of the medium, check valves should be installed on equipment, devices, and pipelines;

2. Check valves are generally suitable for clean media and should not be used for media containing solid particles and high viscosity;

3. Generally, horizontal lift check valves should be used on horizontal pipelines with a nominal diameter of 50mm;

4. Direct lift check valves can only be installed in horizontal pipelines;

5. For the inlet pipeline of the water pump, it is advisable to use a bottom valve, which is generally only installed on the vertical pipeline of the pump inlet, and the medium flows from bottom to top;

6. The lifting type has better sealing performance and higher fluid resistance than the rotary opening type. It is suitable for horizontal installation on horizontal pipelines and vertical installation on vertical pipelines;

7. The installation position of the swing check valve is not limited. It can be installed on horizontal, vertical, or inclined pipelines. If installed on a vertical pipeline, the flow direction of the medium should be from bottom to top;

8. Swing check valves should not be made into small caliber valves. They can be made into high working pressures, with a nominal pressure of up to 42MPa and a nominal diameter of up to 2000mm or more. According to the different materials of the shell and seals, it can be applied to any working medium and any working temperature range. The medium includes water, steam, gas, corrosive medium, oil, medicine, etc. The working temperature range of the medium is between -196 and -800 ℃;

9. The rotary check valve is suitable for low-pressure large-diameter applications, and its installation is limited;

10. The installation position of butterfly check valve is not limited, it can be installed on horizontal pipelines, as well as on vertical or inclined pipelines;

11. Diaphragm check valves are suitable for pipelines that are prone to water hammer. Diaphragm can effectively eliminate water hammer caused by medium backflow. They are generally used in low-pressure and room temperature pipelines, especially suitable for tap water pipelines. The working temperature of the medium is generally between -12 and 120 ℃, and the working pressure is less than 1.6MPa. However, diaphragm check valves can achieve larger diameters, with a maximum DN of 2000mm or more;

12. Spherical check valves are suitable for medium and low pressure pipelines and can be made with large diameters;

13. The shell material of the spherical check valve can be made of stainless steel, and the hollow sphere of the sealing element can be wrapped in polytetrafluoroethylene engineering plastic, so it can also be applied in pipelines with general corrosive media. The working temperature is between -101 and -150 ℃, the nominal pressure is ≤ 4.0MPa, and the nominal diameter range is between DN200 and DN1200;

14. When selecting check valves for incompressible fluids, the first step is to evaluate the required closing speed, and the second step is to choose 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 can be used to select check valves for incompressible fluids. If the flow range of the medium is large, a deceleration device can be used for check valves for compressible fluids. If the medium flow stops and starts continuously and rapidly, such as at the outlet of a compressor, a lift check valve can be used;

16. The check valve should have its corresponding size determined, and the valve supplier must provide data on the selected size so that the valve size can be found when the valve is fully opened at a given flow rate;

17. For high and medium pressure check valves below DN50mm, vertical lift check valves and straight through lift check valves should be selected;

18. For low-pressure check valves below DN50mm, butterfly check valves, vertical lift check valves, and diaphragm check valves should be selected;

19. For high and medium pressure check valves with DN greater than 50mm and less than 600mm, rotary check valves should be selected;

20. For medium and low pressure check valves with DN greater than 200mm and less than 1200mm, it is recommended to use wear-resistant spherical check valves;

For low-pressure check valves with DN greater than 50mm and less than 2000mm, butterfly check valves and diaphragm check valves should be selected;

22. For pipelines that require minimal water hammer impact or no water hammer when closed, it is advisable to use slow closing rotary check valves and slow closing butterfly check valves.

        Shanghai Ocean Pump and Valve Manufacturing Co., Ltd. is a specialized water pump company that integrates research and development, manufacturing, testing, and sales. Located in Jinshan District, Shanghai, our products are sold well in more than 20 countries and regions. The factory covers an area of 36600 square meters, with a building area of 20000 square meters and more than 280 sets of production equipment. The registered capital of the company is 50.08 million yuan, making it one of the largest production and sales enterprises in China's similar water pump industry.

       The company's main products include clear water centrifugal pumps, multi-stage pumps, submersible pumps, sewage pumps, water supply equipment, sewage lifting equipment, oil separation equipment, integrated prefabricated pump stations, HYB type frequency conversion cabinets, and HYK type electric control cabinets. The company has introduced advanced production and testing equipment to ensure the quality of its products. All products have passed the inspection of the National Industrial Pump Product Quality Supervision and Inspection Center! Widely used in various industries such as petroleum, chemical, power plants, chemical fibers, urban construction, railways, military research, pharmaceuticals, environmental protection, metallurgy, building water supply and drainage engineering, fire protection systems, papermaking, mining, tap water, agricultural water conservancy, fertilizers, etc.