Selection standard of check valve

The selection standard of check valve is as follows:

1. In order to prevent reverse flow of medium, check valve shall be installed on equipment, device and pipeline;

2. Check valve is generally suitable for cleaning medium, not suitable for medium with solid particles and high viscosity;

3. Generally, horizontal lift check valve shall be selected for horizontal pipeline with nominal diameter of 50mm;

4. Straight up and down check valve can only be installed in horizontal pipeline;

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

6. The lift type is better than the swing type in terms of sealing performance and large fluid resistance. The horizontal type should be installed on the horizontal pipe and the vertical type on the vertical pipe.

7. The installation position of 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 medium shall be from bottom to top.

8. The swing check valve should not be made into a small diameter valve, which 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 at most. It can be applied to any working medium and any working temperature range according to different materials of shell and seal. The medium is water, steam, gas, corrosive medium, oil, medicine, etc. The working temperature range of medium is - 196-800 ℃.

9. The application of swing check valve is low pressure and large diameter, and the installation is limited;

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

11. The diaphragm check valve is suitable for the pipeline prone to water hammer. The diaphragm can well eliminate the water hammer produced by the medium countercurrent. It is generally used in the low-pressure and normal temperature pipeline, especially for the water pipeline. The working temperature of the medium is generally between - 12-120 ℃, and the working pressure is less than 1.6Mpa, but the diaphragm check valve can be made of large caliber, and the maximum DN can be more than 2000mm.

12. The ball check valve is suitable for medium and low pressure pipelines and can be made into large caliber;

13. The shell material of the ball check valve can be made of stainless steel, and the hollow sphere of the seal can be wrapped with polytetrafluoroethylene engineering plastic, so it can also be applied in the pipeline of general corrosive medium. The working temperature is between - 101-150 ℃, the nominal pressure is ≤ 4.0Mpa, and the nominal diameter range is between dn200-dn1200.