How to Choose Check Valves Correctly
The function of a check valve is to only allow medium to flow in one direction and prevent flow in the opposite direction. Commonly used check valves are divided into two types: lift and swing. How to choose a check valve correctly?
On high-pressure and small diameter equipment pipelines, lift check valves are usually used.
For pipelines that require a small pressure drop, it is not advisable to choose a lift check valve because of its high flow resistance. Instead, butterfly check valves or swing check valves should be chosen.
In pipelines with high pressure fluctuations and special requirements, in order to prevent damage to the valve disc due to water hammer, a silent check valve or a swing check valve with a buffer device should be selected.
When the diameter is large, use a multi disc swing check valve.
At the outlet of the boiler feed pump, a dedicated air discharge check valve should be selected to prevent medium backflow and improve pump efficiency. It is used for the bottom valve of the water pump suction pipe.
Ordinary swing check valves or lift check valves should try to avoid having a larger diameter. In order to fully open or open the check valve to the appropriate position at the minimum flow rate, in some cases, the diameter of the installed check valve should be smaller than the corresponding pipe diameter.
In order to meet the needs of various applications, check valves are also diverse, such as spherical check valves, threaded lift stop check valves, swing check valves with no impact, swash plate check valves, conical diaphragm check valves, etc.
Depending on the medium, the valve disc can be made entirely of metal, or it can be embedded with leather, rubber, or other alloy materials such as synthetic covers or thermal spraying.
