Check valve selection, cannot not know selection criteria

1, in order to prevent medium counter-current, shall be installed in equipment, devices and pipeline check valve; 2, the check valve generally applies to clean medium, should not be used in medium containing solid particles and viscosity is bigger; 3, generally on the level of nominal menstruation 50 mm pipe should be choose vertical lift check valve; 4, cut-through lift check valve can be installed in horizontal and vertical pipe. 5, for import pipeline pumps, appropriate chooses bottom valve, bottom valve installed in the pump only commonly imported vertical pipe runs, and the medium flows from bottom to top; 6, elevating the swing sealing good, fluid resistance is big, horizontal should be installed in horizontal pipe runs with vertical installed in vertical pipe runs; 7, swing check valve installation position is not restricted, and it can be installed in a horizontal, vertical or inclined line, such as in a vertical pipe runs, the medium flows from bottom up; 8, swing check valves should not be made into a small-bore valves, can make high working pressure, the PN can be up to 42 mpa, and DN also can do a lot, the maximum can reach more than 2000 mm. According to the shell and packing material can be applied to any working medium and any working temperature range. Medium for water, steam, gas, corrosive medium, oil, medicine, etc. Medium in - working temperature range 196 - - Between 800 ℃; 9, applicable occasions are low pressure, large diameter and installations is restricted; 10, butterfly check valve installation position is not restricted, can be installed in a horizontal pipe road, also can be installed in vertical or inclined line; 11, the diaphragm type check valve is suitable for easy 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 working temperature in a normal medium - 12 - - Between 120 ℃ and job stress in 12, ball check valve is suitable for the low pressure pipe, 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 the pipeline corrosion medium can also be applied, in - operating temperature 101 - - Between 150 ℃, its nominal pressure & le; 4. 0 mpa, nominal drift diameter range in 200 & ndash; 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, the valve supplier must provide the size of the selected data, so you can find under a given flow when the valve is fully open valve size; 17, for high pressure check valves under DN50mm, appropriate chooses vertical lift check valve and straight-through lift check valve; 18, for low pressure under DN50mm check valve, appropriate chooses butterfly check valve, vertical lift check valves and diaphragm type check valve; 19, for the DN is greater than 50 mm, less than 600 mm high pressure check valves, appropriate chooses swing check valve; 20, for DN is greater than 200 mm, less than 1200 mm in the low pressure check valve, appropriate chooses no wear ball check valves; 21, the DN is greater than 50 mm, less than 2000 mm of low pressure check valve, butterfly check valve is used in the Iraq and diaphragm type check valve; 22, for closing water hammer impact is small or no water hammer pipe, appropriate chooses slow closed gently swing check valve closed butterfly check valve.