Adjustable Temperature Type Devices
Capillary and Bulb and Capillary Type Controls
How They Work:
These larger and more costly devices are used when remote temperature sensing and control capabilities are required. The switching function of the device is not located at the same place where the temperature sensing is taking place. For these devices to function, the capillary tube of the "bulb," or oil filled reservoir is placed where the temperature sensing is to be preformed. As heat increases or decreases at the capillary end or the bulb end of the tube, high temperature oil expands or contracts and moves through a "capillary tube." This tube is attached to a pressure switch that opens and closes a set of electrical contacts to control the temperature of the application. These devices normally utilize an additional bimetal element to compensate for changes in ambient room temperatures.