Temperature

Unlike most dial indicating instruments, the Bi-Metal thermometer has no pinion and segment movement and the pointer is directly driven by the coiled bimetallic strip. This simple, yet rugged construction ensures long, trouble free service with enduring accuracy.
Nitrogen Gas thermometers are designed for the accurate measurement of temperature in a wide variety of industries: Heating, ventilation, and air conditioning (HVAC), nuclear, chemical, and petrochemical plants, pulp and paper, food industries, refrigeration industries, diesel, exhausts and turbines, refineries, and compressors. Ideally suited to the nuclear and food industries (where the use of mercury is prohibited)....
The operation of the glass thermometer is like that of other thermometers using the liquid or gas expansion principle. The sealed glass capillary contains a small bulb filled with a liquid. This fluid will expand with the application of temperature and will rise into the capillary. A scale is fixed in a corresponding position next to the capillary. The divisions are etched on to the glass itself and the scale is printed on to the corresponding “V” formed aluminium housing. The assembly of the thermometer is practical and resistant to breakage if correctly installed.