This valve is installed in the down stream of sampling systems/heat exchanger. The valve responds only to temperature. Under the normal operation the valve is fully open. If the sample temperature increases within the operating temperature (120ºF), The thermal actuator modulates the valve to close the inlet orifice. The valve automatically opens as the thermal actuator cools.
The heart of this valve is a solid to liquid phase change thermal actuator. The actuator contains Thermoloid® compound which changes phase from solid to a liquid as the temperature increases. As phase change occurs the volumes of Thermoloid® material changes significantly with the liquid volume greater than the solid volume. Since Thermoloid® is essentially incompressible under normal operating loads & it is sealed into a rigid actuator housing, only piston can move and extend as the volume increases. This motion is used to open or close the valve.