Thermometers

Analog thermometers come in a wide variety of measuring technologies. Each has it’s advantages and disadvantages. For HVAC and Commercial applications the Industrial Glass Thermometer is the most popular choice. This type of thermometer utilizes a vertical glass column typically filled with a colored organic fluid that that has a linear coefficient of expansion. The fluid in the column rises or falls depending on the temperature and is correlated with a graduated temperature scale. The enclosures on these thermometers are typically not a weather proof case and are best suited for dry indoor applications.

For more rugged applications a bimetal thermometer is a better choice. This would include process, chemical, biopharm, and other demanding applications where a stainless steel weather proof enclosure would be a must have. The sensing element is a “bimetallic” strip of two dissimilar metals bonded together and wound in a helix. Each metal expands or contracts differently when temperature changes. This has the effect of the coil unwinding (as heated) or compressing (as cooled). The pinion shaft of the thermometer is directly coupled to the bimetallic element and turns as the coils is actuated. This moves the pointer clockwise or counter clockwise across the dial face of the thermometer. Each temperature scale is correlated with the precision movement of the bimetallic elements change to process conditions. The minimization of moving parts in this type of thermometer makes it long lasting. Case filling is also available for high vibration applications.

The above are just two of the wide range of thermometer types available. Others include, Vapor Tension thermometers, Gas Actuated thermometers (Great for high temperature applications exceeding 700°F continuous operating conditions up to 1200°F), and Liquid Tension Actuated Thermometers. There are also a variety of Digital Type Thermometers. Solar Digital Thermometers, Battery Operated Digital Thermometers, etc. These are all based on either a 2 wire NTC thermistor, a 2 or 3 wire RTD, or Thermocouple, but packaged in a “thermometer” style presentation. You can find out more about RTD and Thermocouple products here.

We stock both Bimetal thermometers in 3″ and 5″ dials, in both back mount and adjustable angle configurations and Industrial Glass Thermometers in 3.5″ and 6″ stems in a wide array of temperature ranges. We also stock thermowells for both types of thermometers