Selection
selecting standard:
1.In order to prevent the media reflux, should install check valve on the equipment, devices and pipes.
2、Check valve is generally applicable to pure media, not for containing the solid particles and larger viscosity media
3、Generally in nominal diameter 50mm horizontal pipes, we should select vertical lift check valve
4、Straight-down check valve can be installed both in horizontal pipe and vertical pipe
5、For the pump inlet pipeline, should use the foot valve, foot valve, generally installed in the pump inlet vertical, and the media flows bottom-up
6、lift type sealing performance is better that swing type, fluid resistance is large, horizontal type should installed in the horizontal pipe and vertical type installed in the vertical pipe
7、Swing check valve installation position without restriction, it can be installed in horizontal, vertical or inclined pipelines, such as mounted in a vertical pipe, medium flow to the bottom up
8、Swing check valves are not small, can make the valve is made of high working pressure, can achieve 42MPa PN, but also can do big, DN 2000mm can reach above. According to the different shell and seal materials can be used in any medium and any working temperature range. Medium for water, steam, gas, oil, corrosive medium, pharmaceutical, etc. Medium working temperature range in - 196-800 ° c
9 and applicability is low, and the installation of heavy-calibre restrictions on occasion,
10 and butterfly check valve installation position of unrestricted, may be installed in a horizontal pipe road, can also be installed in vertical or inclined pipe,
11 and diaphragm check valves are used to easy generation water piping, diaphragm may very well to eliminate the medium upstream of the water, it is generally used in low temperature pipes, especially suitable for water pipe, the average temperature in medium - 120 degrees between December - 160 MPa pressure of work, ", but the diaphragm check valve can be larger diameter, DN 2000mm can reach above,
12 and spherical check valve suitable for medium voltage lines, can make big caliber,
13 and spherical shell material of check valve can be used stainless steel, sealers hollow spheres can package ptfe plastics in general corrosive medium, so the temperature can be applied, in - 101-150 ° c, the nominal pressure between than 4.0 MPa, nominal given.it range between 200-1200
14 for non-compressible fluid, with the first check valve selection to need closing speed, the second step is to evaluate choice may satisfy the need of closing speed check valve type,
15 for compressible fluid in check valve can choose not to use compressible fluid stop-check valves of similar method choice, if the media, for flow category compressible fluids can use the check valve, if a slow flow of medium for quick stop and start for the compressor, such as export, use the movements of check valve,
16 and stop-check valves should determine the size of the response, the valve supplier must provide selected data, this size can be found under the given velocity when the valve is fully open the valve size,
17, for DN50mm following high-medium pressure check valve, appropriate chooses vertical lift check valve and check valve and straight-through type,
18 for DN50mm below for low check valve, appropriate chooses butterfly check valve, vertical lift check valve and check valve diaphragm,
19, for more than 50, less DN 600mm high pressure check valve, appropriate chooses swing check valves,
20.For more than 20, and less than 200mm DN 1200mm in low-pressure check valve, appropriate chooses not wear ball check valves,
21, for more than 50, less than 2000mm DN low-pressure check valves, butterfly check valve selection and diaphragm check valve,
22 the water requirements for closes relatively small impact or water piping, appropriate chooses slow close-type swing check valves gently close family fabaceae check valves.
