... DN: 50-700mm(2-28") CST42Y Automatic Re-Circulating Control Valve (reflux valve) is installed at the outlet of centrifugal pump to provide ... and prevent backflow of medium through the pump outlet. The valve is widely used in industrial fields, such as the outlet ... , Hastelloy, Monel, 316,310,304,WC6 and etc. Automatic Recirculation Control Valve (Return Valve)