Check valve, also known as counter-flow valve, check valve, back pressure valve, check valve. This kind of valve is automatically opened and closed by the force generated by the flow of the medium itself in the pipeline, which belongs to an automatic valve. Check valve for piping systems, its main role is to prevent media backflow, to prevent the pump and its drive motor reversal, as well as the container media release. Check valves can also be used on lines where the pressure may rise to a level above the pressure of the main system auxiliary system. Ball check valves are made of rubber bag for the valve flap, their principle is the role of the medium, the valve body can slide back and forth within the slide, which play to open or close the valve. HQ44X single ball micro-ball check valve, HQ45X double ball micro-ball check valve is characterized by large flow, flow resistance pressure loss, good sealing performance, muffler off, reducing the water shock wave. Horizontal or vertical installation can be. Miniature ball check valve can be used for cold water, hot water, industrial and domestic sewage pipe network such as the pump outlet to prevent the media back. To prevent backflow of media, check valves should be installed on equipment, fittings, and piping.