Constant temp. drain valve

The utility model discloses a constant temperature drain valve, which is an automatic valve which can automatically stop the leakage of steam and can also automatically discharge condensed water. The utility model is characterized in that the casing of a valve body and the inner core of the valve body form a whole, a thermal sensitive element is positioned at the point of a steam inlet, a valve seat opening on a valve seat is an inward concave semi-round sphere shape which can be assuringly fit with the semi-round sphere-shaped head of the front part of the valve core. The valve can be reliably closed, the utility model overcomes the defects of the various existing drain valve that the steam leakage phenomenon can occur, the use is safe, and large amount of energy can be saved.