Do you know how common thermometer is classified?

Thermometer is mainly used to measure the temperature of the measured medium, according to the installation environment and the working principle, we classify the thermometer. Common laboratory thermometers, bimetal thermometer, pressure type thermometer, today we are both about the working principle of the thermometer. Laboratory thermometer, general laboratory use thermometer are glass rod thermometer, its principle is very simple, because mercury heat to cold, as to why not water, because water in 4 degrees, thermal expansion, cold and mercury expansion coefficient is larger, there are obvious changes in the inside of alcohol, is red, alcohol thermometer is suitable for measuring low temperature ( - 78 ~ + 110 degrees) Lateral, mercury thermometer is suitable for high temperature ( About 15 ~ 300 degrees) 。 Inflation pressure type thermometer is based on the principle of the liquid law, namely the quality of a certain liquid, under the condition of constant volume, pressure and temperature of the liquid is linear. Gas, steam pressure and temperature is also a certain functional relation, so the uniform pressure type thermometer scale should be equal. Pressure type thermometer consists of temperature inductive medium temperature filling bag, the pressure element ( Capillary) And pressure sensitive components ( Spring tube) Composition. Bimetallic thermometer working principle is to round shape into threaded heat bimetallic strip as thermal devices, and put it in a protective sleeve tube, one end is fixed, known as the fixed end, the other end of the connection on a thin shaft, called the free end. Spool at the free end is equipped with a pointer. When the temperature changes, the resulting thermal devices the free end of the rotation, drive the thin axis from the Angle of the pointer changes, corresponding temperature indicator on the dial.