The temperature as physical unity cannot be measured directly but only upon a phenomenon related to temperature change, like the volume or length expansion of gases, liquids or solid materials. When a metallic element is submitted to temperature changes, its length varies. This physical property has been used and developed to build temperature measuring devices. The bimetallic sensor is made of two coils, twisted together and welded at their end. Being selected on purpose with very different thermal expansion coefficients, the two materials will generate a torque at their free end when submitted to temperature changes. Thanks to its double helicoid technology, RÜEGER offers the shortest bimetal systems of the world, which guarantees accuracy and short time temperature measurements.


The great success of the bimetal thermometer is due to it outstanding characteristics, such as

– simple and sturdy design

– linear dial scaling with very good legibility

– good precision and nearly no indication hysteresis

– no aging behavior –> very long mean time between calibrations

– indication not influenced by ambient temperature or air pressure

– no need of electrical energy

– short sensitive length for spot measurement


All these features make the bimetal thermometer to the best solution for reliable, cost effective, precise and safe temperature measurement. With RÜEGER’S over 60 year’s experience as one of the world’s leaders in industrial temperature measurement a wide range of thermometers are available covering the highest demands in precision, reliability and ruggedness for applications from laboratory use to marine engine equipment, chemicals, food, pharma.





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