Check valve refers to the flow of the media itself and automatically open, closed disc, used to prevent the backflow of media valves, also known as reverse valve, one-way valve, countercurrent valves and back pressure valves. Check valves are an automatic valve, which is mainly to prevent the backflow of media, to prevent the pump and drive motor reversal, and the leakage of the container media. The check valves can also be used to provide the piping for the pressure that may ascend to the auxiliary system that exceeds the system pressure. Check valves are mainly divided into rotary type check valve (according to the center of gravity rotation) and lifting type check valve (along the axis movement).
Check valves This type of valve is the function of only allowing the medium to flow in one direction, and prevents the reverse direction flowing. Usually this valve is automatically operated, in a direction flowing under the pressure of the fluid, the disc open, fluid flow in reverse direction, by the fluid pressure and the disc's self-fitting disc function in the valve seat, thereby cutting off the flow.
The check valve belongs to this type of valve, which includes the swing check valve and the lifting type check valve. The Swing check valve has a hinged mechanism, and a door-like disc is freely leaned on the inclined seat surface. To ensure that the disc can reach the proper position of the seat surface each time, the disc is designed in the hinge mechanism so that the disc has sufficient swing space and the disc is genuine and comprehensive with the valve seat contact. The disc can be made of metal and can be inlaid with leather, rubber, or synthetic coverage, depending on the performance requirements. The Swing check valve is completely open in the condition that the fluid pressure is hardly hindered, so the pressure drop through the valve is relatively small. The disc of the lifting check valve is located on the seat sealing surface of the body. This valve in addition to the disc can freely move away, the rest of the same as the cut-off valve, fluid pressure to lift the disc from the seat sealing surface, the media back to the valve disc to the seat, and cut off the flow. Depending on the conditions of use, the disc can be a full-metal structure or a rubber pad or a rubber ring mounted on the disc holder. Like the cut-off valve, the fluid passes through the lifting type check valve The passage is also narrow, so through the lifting type check valve pressure drop than the swing type check valve is bigger, and the swing check valve flow receives the restriction very few.