Description:
Check valve refers to a valve whose opening and closing parts are circular discs and rely on its own weight and medium pressure to generate actions to block the back flow of the medium. It is an automatic valve, also called check valve, one-way valve, return valve or isolation valve. The movement of the disc is divided into lift type and swing type. The lift check valve is similar in structure to the shut-off valve, but lacks the valve stem that drives the disc. The medium flows in from the inlet end (lower side) and flows out from the outlet end (upper side). When the inlet pressure is greater than the sum of the weight of the disc and its flow resistance, the valve is opened. On the contrary, the valve is closed when the medium flows back. The swing check valve has a disc that is inclined and can rotate around the axis, and the working principle is similar to that of the lift check valve. The check valve is often used as the bottom valve of the pumping device to prevent the backflow of water. The combination of check valve and globe valve can play a role of safety isolation. The disadvantage is that the resistance is large and the sealing performance is poor when closed.