Selection criteria for check valves

The selection criteria of the check valve are as follows:

1. In order to prevent the medium from flowing back, check valves should be installed on the equipment, devices and pipelines;

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

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

4. The straight-through lift check valve can only be installed in horizontal pipelines;

5. For the inlet pipeline of the water pump, a bottom valve should be selected. The bottom valve is generally only installed on the vertical pipeline at the inlet of the pump, and the medium flows from bottom to top;

6. Compared with the swing type, the lifting type has better sealing performance and greater fluid resistance. The horizontal type should be installed on a horizontal pipeline, and the vertical type should be installed on a vertical pipeline;

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

8. The swing check valve should not be made into a small-diameter valve, it can be made into a very high working pressure, the nominal pressure can reach 42MPa, and the nominal diameter can also be very large, which can reach more than 2000mm. According to the material of the shell and the seal, it can be applied to any working medium and any working temperature range. The medium is water, steam, gas, corrosive medium, oil, medicine, etc. The working temperature range of the medium is between -196--800℃;

9. The applicable occasion for swing check valve is low pressure and large diameter, and the installation occasion is restricted;

10. The installation position of the butterfly check valve is not restricted. It can be installed on a horizontal pipeline, or on a vertical or inclined pipeline;

11. Diaphragm check valve is suitable for pipelines that are prone to water hammer. The diaphragm can well remove the water hammer generated when the medium flows back. It is generally used on low-pressure and normal temperature pipelines, and is especially suitable for tap water pipelines and works with general media. The temperature is between -12-120℃, and the working pressure is less than 1.6MPa, but the diaphragm check valve can achieve a larger diameter, and the DN can reach more than 2000mm;

12. The spherical check valve is suitable for medium and low pressure pipelines and can be made into a large diameter.