A check valve is a valve that automatically prevents the backflow of fluid. It can be opened under the pressure of the fluid, and it can also be automatically closed under its own gravity and other factors, so as to prevent the fluid from flowing backward. It is only allowed to open in one direction, which prevents unexpected accidents. When you use a check valve, you need to understand its installation method, so what is the working principle of the check valve? What is the installation method of the check valve? WSV, a check valve manufacturer, will give you a detailed introduction.
Check valves may also be used on lines supplying auxiliary systems where the pressure may rise above system pressure. Check valves can be mainly divided into swing check valves (rotating according to the center of gravity) and lift non return check valves (moving along the axis). A check valve only allows opening in one direction and blocks the opposite direction. Usually, this kind of check valve works automatically. Under the action of fluid pressure in one direction, the stainless steel check valve opens, and when the fluid is in the opposite direction, the fluid pressure and the self-coincident valve of the valve act on the valve seat, thereby cutting off.
(1) Swing check valve
The valve of the swing check valve is disc-shaped and can rotate around the axis of the valve seat passage. Because the channel in the valve is streamlined, the resistance is smaller than that of the lift non return check valve, and it is suitable for low flow rate and large-diameter occasions with infrequent changes. However, it is not suitable for pulsating flow, and its sealing performance is not as good as that of lift check valves. There are three types of swing check valves: single type, double type and multi-half type. These three forms are mainly divided according to the diameter of the valve, and the purpose is to prevent the hydraulic shock from being stopped or reversed.
(2) Lift check valve
The valve of the lift non return check valve slides along the vertical centerline of the valve body, so it can only be installed on horizontal pipes. Balls can be used on high-pressure small-diameter check valves. The shape of the valve body of the lift check valve is the same as that of the globe valve (it can be used in common with the globe valve), so its fluid resistance coefficient is larger. Its structure is similar to the globe valve, and the valve body and valve are also the same as the valve globe type. The upper part of the valve and the lower part of the bonnet are machined with guide sleeves, and the valve disc guide can be freely raised and lowered in the valve guide guide. When the flow is downstream, the valve is opened by thrust, and when the flow is stopped, the valve will naturally land on the valve seat to prevent reverse flow. The direction of the inlet and outlet passages of the general lift check valve is perpendicular to the direction of the valve seat passage. Vertical lift check valve, its inlet and outlet channels are in the same direction as the valve seat channel, and its resistance is smaller than that of the straight-through type.
(3) Disc check valve
The disc non return check valve has a simple structure, and the valve rotates around the pin in the valve seat. It can only be installed on horizontal pipes and has poor sealing.
(4) Pipeline check valve
In-line check valve is a new type of valve that slides along the centerline of the valve body. It is small in size, light in weight and good in processing technology. But its fluid resistance coefficient is slightly larger than that of swing check valve.
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