Check valves rely on the media itself refers to flow automatically open and close the valve, the valve is used to prevent the media back. It relies on the flow of fluid to open, when the flow is interrupted by the return mechanism of weight or back only to close. Its structure can be divided according to a check valve, lift check valve: valve body along the vertical centerline of the valve slide, features: its fluid drag coefficient greater than the swing good seal, horizontal or vertical flap can not be wrong (horizontal and vertical lines) two, swing check valve: valve seat around the outside of the valve pin rotating valve silencer, features: poor sealing, low flow resistance should not be made of small caliber ball-type check valve, mounting position wide, but when the vertical line, under the media should be first. Third, the disc check valve: valve rotation about the pins inside the valve seat. Simple disc check valve structure, can only be installed in horizontal pipelines, poor sealing. Fourth, pipeline valve, the valve body along the center line of the slide valve. Pipeline valve is a check valve emerging steel, its small size, light weight, good processing valve, check valve is one of the development direction. But the fluid drag coefficient is slightly larger than the swing check valve, also known as backflow valves, check valves, back-pressure valve, check valve. Such valves are in the pipeline by the force generated by the flow of the medium itself automatically turned on and off, is an automatic valve. Check for the pipeline system, its main role is to prevent the media back, to prevent the pump and its drive motor reverses, and discharge the container media. Pressure valve can also be used for more than one of the primary system pressure may rise to an auxiliary system supplies the pipeline. Ball check valve direct _ England electromechanical (certified) _ check provided by the Dongguan City Electrical Equipment Co., Ltd. of England. England City Electrical Equipment Co., Ltd. (www.gdyinglun.com) is a leader in Dongguan, Guangdong, hydraulic machinery and parts, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. In England electromechanical leadership with the staff warmly welcome all inquiries negotiations to create a better future for the British electrical and mechanical.