Capillary Thermostat exTHERM-AT

The explosion-proof surface-mounted thermostats of the exTHERM series are built to monitor and control temperatures in potentially ex-hazardous areas. The use in environments with gas and steam (zones 1 and 2); as well with conductive dust (zones 21 and 22) is permitted.

The exTHERM-AT is available as safety temperature monitor (STW). The thermostats work according to the liquid expansion or gas expansion principle. The electrical switching element is a pressure-resistant encapsulated thermostat with a snap-action switch. Stable switching points when ambient temperatures fluctuate are made possible by the standard ambient temperature compensation. If the temperature on the temperature probe exceeds the setpoint value, the microswitch is activated by the transmission mechanics and the electrical circuit is opened or closed. If the temperature falls below the selected setpoint value (by the amount of the switching differential), the microswitch is reset to its initial position. If the measuring system is destroyed (i.e. if the expansion fluid escapes) the pressure in the membrane of the STW drops and permanently opens the electrical circuit. Unlocking is then no longer possible.