Automatic steam-trap freeze-protection drain

The automatic drain releases retained liquid from a steam trap after steam shutdown to reduce freezing risk. Its duty is distinct from a check valve or vacuum breaker. The section shows a spring and drain member within a small threaded body. The listed construction is stainless steel, with maximum allowable pressure of 41 bar, maximum temperature of 177 °C and a 1/2-inch NPT connection. Match the installation and drainage route to the trap arrangement and shutdown conditions.