What are Bimetal Gauges/Thermometers and how do they work?

The bimetal thermometer measures by thermal expansion.

A bimetal thermometer uses a bi metal spring as temperature sensing element. This technology uses a coil spring made of two different types of metals that are welded or fastened together. These metals could include copper, steel, or brass. One must have low heat sensitivity while the other metal has high heat sensitivity. Whenever the welded strip is heated, the two metals change length based on their individual rates of thermal expansion. Since the two metals expand to different lengths, the bimetallic strip is forced to bend or curl towards the side with a lower coefficient of thermal expansion. The movement of the strip is used to deflect a pointer over a calibrated scale which then indicates temperature to the user. Their construction is simple, yet rugged. They are suitable for most applications and measure a range from -50°C to 600°C. They come with multiple entry combinations and provide high repeatability with an accuracy ± 1% FSD.

  • The advantage of bimetal temperature gauges is its relatively low cost and robust design.
  • The disadvantage of bimetal temperature gauges compared to electrical temperature devices is that you must be physically present at the point of measurement to take the reading.

Bimetal gauges/thermometers are used in a variety of industries in their process control such as chemical, oil and gas, refining, pulp and paper, power, and energy and water-wastewater industries and machine building.

What are the Features of a Bimetal Gauge:

  • Rugged construction
  • Bottom/Back entry, every single angle construction
  • Fast response
  • Protection class IP-67
  • Accuracy ± 1% FSD
  • High repeatability, low hysteresis
  • Hermetically seal case

What are the Specifications of a Bimetal Gauge:

Bi metal gauge specifications

Note: 1) For minimum insertion length essential for proper sensing, contact our design department.
2) Three-point calibration certificate accompanies each thermometer.

To make it easier for you to order a Bimetal gauge please click on the how to order link and this will assist you having all the information you require before contacting us. If you are having difficulty contact at the office and we will assist you.


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