When do I need to use a Thermowell?
A Thermowell is a device for physically, but not thermally, isolating a bulb or probe from the temperature media being sensed. Thermowells should be used to protect the bulb from otherwise intolerably corrosive media or excessive pressures. All electromechanical temperature switches may be used with a Thermowell when pressures exceed 300 psi, if high velocities are present and with corrosive or abrasive media. Thermowells also allow removal of the temperature switch or sensor without loss of contained media. When using a thermowell with a local mount temperature switch, two set screws are provided to secure the switch in the well allowing 360° rotation for easier electrical connection and readability. The use of a Thermowell may increase response time to temperature change. By using heat transfer material, the increase can be kept to a minimum.
