ZhengFeng water & API check valves are widely used in water & oil pipelines all over the world. In our case, they are used at the entrance of hydropower station turbine, and they are installed at the water supply, oil pipeline and natural gas system. They are often used instead of cast and forged gate valves, carbon check valve, pressure seal check valve and so on. Although the check valve can shut off the backflow medium, its flow resistance coefficient also has a very important effect in performance, because the return valve is different from the gate valve and butterfly valve so that the gate or disc is fully open without any flow resistance. The check valve needs the medium to flush the disc before flowing through the valve body. ZhengFeng’s check valve is our own r & d team to travel around the world and well-known check valve manufacturers to communicate, understand and on this basis, our own unique innovation and development. ZhengFeng check valve has a very small resistance coefficient, automatic shut-down when backwater, and reliable performance, and why do we say that? As we have our own designed and developed valve testing system, we conduct performance and sealing test for each newly developed and finished production valve to ensure that the check valve can be normally used under operating conditions and meet the final requirements of customers. The spring and disc of the feed check valve play an important role in the whole valve. Therefore, for each spring, we will use the fatigue testing machine and the elastic testing machine to ensure that the spring can maintain its normal state for a long time; For each disc, we will use precision equipment, such as numerical control equipment, processing center.It is because of the previous process to the final inspection of the assurance that the check valve is safe.