[DIN Lift check valve]-also known as one-way valve or check valve, it is automatically opened and closed by the flow of the medium itself in the pipeline and the force generated by the spring, which belongs to an automatic valve. Check valves are used in pipeline systems. Their main functions are to prevent backflow of the medium, to prevent the pump and its drive motor from reversing, and to release the medium in the container. The check valve can also be used to replenish the auxiliary system where the pressure may rise above the pressure of the main system.
The function of the check valve is to only allow the medium to flow in one direction, and to prevent reverse flow. Usually this kind of valve works automatically. Under the action of the fluid pressure flowing in one direction, the valve flap opens; when the fluid flows in the opposite direction, the self-coincidence of the fluid pressure and the valve flap acts on the valve seat, thereby cutting off the flow. Among them, the internal thread check valve and the butterfly check valve belong to this type of valve, which includes a swing check valve and a lift check valve.
The swing check valve has a hinge mechanism, and a flap like a door freely rests on the inclined seat surface. In order to ensure that the valve flap can reach the proper position of the valve seat surface every time, the valve flap is designed in the hinge mechanism, so that the valve flap has enough unscrewed space, and the valve flap is truly and fully contacted with the valve seat. The valve flap can be made entirely of metal, or it can be inlaid with leather, rubber, or a synthetic cover, depending on the performance requirements. When the swing check valve is fully open, the fluid pressure is almost unimpeded, so the pressure drop through the valve is relatively small.