The filled system thermometers are manufactured using Inert gas which is environmental friendly and works on the principle of volumetric gas expansion. These gauges are also manufactured with longer capillaries to meet the specific requirements of the user. The case compensation is provided for rigid stem type thermometers and full capillary compensation is provided for gauges with longer capillaries. The ranges are available from -200 °C to 800°C.
The bimetal thermometers are manufactured using the two dissimilar metals having different thermal expansion coefficient. The bimetal strip is formulated into the helix which acts as a sensor and when subjected to heating zone. The expansion difference (due to thermal expansion coefficient) between these two elements leads to an indication on the dial. The ranges are available from -80 °C to 600°C.