... Automatic Re-Circulating CCirculatin Nominal Pressure PN: 1.6-25MPa(150-1500Lb) Nominal Diameter DN: 50-700mm(2-28") CST42Y Automatic Re-Circulating Control ... , nickel, zirconium, Hastelloy, Monel, 316,310,304,WC6 and etc. Automatic Recirculation Control Valve (Return Valve)