Check valve refers to a kind of valve whose opening and closing parts are circular flaps and rely on its own weight and medium pressure to block the backflow of medium. It is an automatic valve, also known as check valve, check valve, return valve or isolation valve. The movement mode of valve disc is divided into lifting type and swing type. The lift check valve is similar to the cut-off valve in structure, only lacking the stem that drives the flap. 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 weight of the flap and the flow resistance, the valve is opened. On the contrary, the valve is closed when the medium flows backward. The swing check valve has an oblique flap that can rotate around the axis. The working principle is similar to that of the lift check valve. Check valves are often used as bottom valves of pumping devices to prevent the backflow of water. The combined use of check valve and globe valve can play a role of safety isolation. The disadvantage is that the resistance is large, and the sealing is poor when closed.
With the acceleration of the reorganization of the valve industry, the future industry will be the competition between the quality and safety of valve products and product brands. New products and technical transformations can gradually improve the technical level of products, meet the domestic equipment, and fully realize the localization of valves. Under the huge demand environment, China's valve manufacturing industry will surely show better development prospects.
