How to choose suitable for industrial use thermometer?

According to the installation and use of the environment is different, need to install the industrial use of the types of thermometer, model is different. So how do we choose suitable industrial thermometer? Distinguish between a lot of methods, today we just came up out of their working principle. 1. Pressure type thermometer is made with full of heat medium temperature bag, the pressure element ( Capillary) And pressure sensitive components ( Spring tube) Of all metal components. Wen bags pack heat medium such as gas, liquid or liquid evaporation. When the temperature measured medium, put the bulb temperature of work material pressure caused by the temperature increase volume expansion. The pressure change the capillary is passed to the spring tube and make it produce certain deformation, and then with the help of a gear or lever transmission mechanism, such as drive the pointer rotation, points out the corresponding temperature. Thus it can be seen that bulb, capillary and bourdon tube when the three important component. 2. Bimetallic thermometer bimetallic thermometer is a kind of measurement in the field of low temperature test instrument. Can be directly measured in the process of various production - 50℃- Liquid + 500 ℃ range steam and gas medium temperature. Bimetallic thermometer is made of round shape into threaded heat dual metallic piece as temperature sensing element, and put it in a protective sleeve, one end fixed ( Fixed end) And the other end, The free end) Connection on a thin shaft, shaft end is equipped with a pointer. When the temperature changes, temperature sensing element of the free end immediately rotation, thus fine axis pointer to produce angular displacement, on the dial indicates that temperature changes due to the heat element has a linear relation with temperature changes, so the location of the bimetallic thermometer pointer indicated is measured temperature value.