Check valve selection criteria

Check valve selection criteria:

1. Check valve should be installed in equipment, equipment and pipelines to prevent the flow of the medium.

2. Check valves are generally applicable to clear and clean media, and are not suitable for medium containing solid particles and viscosity.

3. Vertical lifting and check valves should be used in the horizontal pipe with the common name of 50mm.

4. Direct lift check valves can be installed on horizontal and vertical pipes;

For the pump inlet line, the check valve shall be chosen, and the bottom valve shall be installed only in the vertical pipe which is imported by the pump, and the medium shall flow from the bottom up.

6. The lifting type is better than swing type sealing, the fluid resistance is large, and the horizontal check valve should be installed on the horizontal pipe, vertical in the vertical pipe;

7. The installation position of swing check valve is not restricted. It can be installed in horizontal, vertical or inclined pipelines, such as in vertical pipe, where the flow of medium is to be up;

8. Swing check valves are not suitable for small diameter valve, can be put into high work pressure, PN can reach 42MPa, and DN can be large enough to reach more than 2000mm. Any working medium and any working temperature range can be applied according to the material of the shell and seal. The medium is water, steam, gas, corrosive medium, oil, medicine, etc. Medium temperature range between 196-800 ℃;

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

10. The installation location of the butterfly check valve is not limited, it can be installed on the horizontal pipe road or installed in a vertical or inclined line;

11, the diaphragm type check valve applies to produce water hammer on the pipeline, the diaphragm is a good way to eliminate water hammer produced by a dielectric upstream, it is generally used in low pressure pipe at room temperature, especially suitable for the water pipe, the general work of medium temperature between - 12-120 ℃, pressure < 1.6 MPa, but the diaphragm type check valve can achieve large caliber, DN biggest can reach more than 2000 mm;

Ball check valves are suitable for medium and low voltage lines, which can be made into large diameter.

13, the shell material of spherical check valve can be made of stainless steel, the seals of the hollow spheres can package ptfe engineering plastics, so in general corrosive medium in the pipe can also be applied on the road, between the working temperature at 101-150 ℃, its nominal pressure 4.0 MPa, or less nominal drift diameter range between 200-1200;

But with a check valve, for non-compressible fluid when the choice must first to evaluate need closing speed, the second step is to choose the closing speed could meet the need of the type of check valve;

15, for compressible fluid with check valve when the choice according to non-compressible fluid using similar methods to choose the check valve, if the medium flow field is very big, the check valve can be used for compressible fluid, a speed reducer, if the medium flow continuous period of not to stop and start quickly, as the export of compressor, use the lift check valve;

16. The check valve shall determine the size of the response, and the valve supplier shall provide the data data of the selected dimensions so that the valve size of the valve at a given velocity can be found at full opening;