Check Valve selection criteria, should be in accordance with the following: General in the nominal channel 50mm horizontal pipe should be selected vertical lift check valve; The straight-through type lift check valve can be installed on both the horizontal pipe and the vertical pipe;
In order to prevent the medium countercurrent, the check valve should be installed on the equipment, the device and the piping; Check valve is generally applied to clean media, Not suitable for the medium containing solid particles and large viscosity; for the pump inlet pipe, it is advisable to choose the bottom valve, the bottom valve is generally only installed in the pump inlet vertical pipe, and the medium flow from bottom to top.
Diaphragm type check valve is suitable for easy to produce water hammer on the road, the diaphragm can be very good to eliminate the medium countercurrent when the water hammer, it is generally used in low pressure normal temperature pipe, especially applicable to the water pipe, the general medium working temperature between -12--120℃, working pressure <1.6MPa, But the diaphragm type check valve can achieve larger caliber, the DN can reach above 2000mm maximum.
Swing check valve should not be made into small-caliber valves, can be made very high working pressure, PN can reach 42MPa, and DN can also be very large, the maximum can reach more than 2000mm. Any working medium and any operating temperature range can be applied according to the different material of the shell and the sealing part. The medium is water, steam, gas, corrosive medium, oil, medicine, etc. The medium working temperature range is between -196--800℃ and 9, the application is low pressure large caliber, and installation situation is limited.
Spherical check valve is suitable for medium and low pressure pipe, can be made into large caliber; spherical check valve shell material can be made of stainless steel, sealed parts of the hollow sphere can be wrapped PTFE Engineering plastics, so in the general corrosive medium of the tube can also be applied, operating temperature between -101--150℃, Its nominal pressure is ≤4.0MPa, the nominal flow range is between 200-1200; for incompressible fluids to select the check valve to evaluate the required closing speed, the second step is to select the type of check valve that may meet the required closing speed.