Overcoming the spring resistance makes the valve open or close. When the medium pressure at the inlet end is lower than the inlet end, the vertical check valve: due to the pressure of the medium at the inlet end of the pipeline. The spring pushes the valve core to the valve seat to close the valve, preventing the medium from flowing back, so it has a non-return function. Vertical check valves are widely used in chemical, liquefied petroleum gas, fluid and other industries. According to the structure of the check valve, it can be divided into three types: lift check valve, lift check valve and butterfly check valve.
The valve used to prevent the medium from flowing back is also called check valve, one-way valve, reverse flow valve, and back pressure valve. The check valve is a kind of automatic valve, its main function is to prevent the back flow of the medium, prevent the pump and the drive motor from reversing, and the discharge of the container medium. Check valves can also be used to supply pipelines where the pressure may rise to an auxiliary system that exceeds the system pressure. Check valves can be divided into swing check valves (rotating according to the center of gravity) and lift check valves (moving along the axis). The function of this type of valve is to only allow the medium to flow in one direction and prevent the flow of the direction. Usually this kind of valve is automatically working under the action of the fluid pressure flowing in one direction, the valve flap opens; when the fluid flows in the opposite direction, the fluid pressure and the self-coincidence of the valve flap act on the valve seat, thereby cutting off the flow. Among them, the internal thread check valve and the vertical check valve refer to the automatic opening and closing of the valve clack depending on the flow of the medium itself. Connected check valves belong to this type of valve, including swing check valves and lift check valves. The swing check valve has an intermediary chain mechanism and a valve disc like a door that rests freely on the surface of the inclined valve seat. In order to ensure that the valve clack can reach the proper position of the valve seat surface every time, the valve clack is designed in a chain mechanism so that the valve clack has enough space for turning and makes the valve clack truly and fully contact the valve seat. The valve clack can be made of metal, leather, rubber, or synthetic covering can be inlaid on the metal, depending on the performance requirements. When the swing check valve is fully opened, the fluid pressure is almost unimpeded, so the pressure drop through the valve is relatively small. The valve disc of the lift check valve is seated on the sealing surface of the valve seat on the valve body. Except that the disc can be lifted and lowered freely, the rest of this valve is like a shut-off valve. The fluid pressure lifts the disc from the sealing surface of the valve seat, and the backflow of the medium causes the disc to fall back to the seat and cut off the flow. According to the conditions of use, the valve disc can be an all-metal structure, or it can be in the form of a rubber pad or rubber ring inlaid on the disc frame. Like a stop valve, the passage of fluid through the lift check valve is also narrow, so the pressure drop through the lift check valve is larger than that of the swing check valve, and the flow of the lift check valve is less restricted. 

Nortech is one of the leading industrial valve manufacturers in China with quality certification ISO9001.

Major products: Butterfly Valve, Ball Valve,Gate Valve, Check Valve, Globe Vavlve,Y-Strainers, Electric Acurator , Pneumatic Acurators .