Automatic Condensate Drain Valves

Automatic drainage valves are used on steam distribution networks and condensate lines to discharge liquid during start-up, shutdown, and pressure decay conditions. Their function is to prevent condensate from remaining in low points of piping, reduce the risk of water hammer, and limit vacuum formation or unwanted moisture accumulation before the next start-up. This category includes ARI BR665, ARI condensate discharge temperature limiter, ARI liquid return temperature limiter, and Gestra AK.

Selection is based on operating pressure, closing pressure, fluid temperature, installation position, end connection, and whether manual or automatic draining is required. ARI automatic drain valves are intended for condensate discharge during start-up and shutdown, with adjustable closing pressure and a factory setting of 1.5 bar. Versions with temperature limiter are applied where control of discharge temperature or liquid return temperature is required, with adjustable closing temperature from 60 °C to 130 °C in return-line applications.

Available designs include DIN and ANSI execution, with pressure classes PN16, PN40, Class 150, and Class 300. Connection options include BSP, NPT, flanged, socket weld, butt weld, and union-weld ends. Body materials include EN-JL1040, EN-JS1049, and 1.0460, depending on valve type and design pressure. For ARI units, nominal sizes DN15 to DN25 are specified, with allowable operating pressures up to 12.8 barg for PN16 and 32 barg for PN40, and temperature limits up to 300 °C or 385 °C respectively. The Gestra AK opens by spring force at zero pressure, closes when system pressure reaches the set value, and reopens when pressure falls below that threshold.