What's the difference between ordinary thermometer and bimetallic thermometer?

But we all know that the ordinary thermometer, bimetallic thermometer and we know how much? For bimetallic thermometer in our daily use is also very much, let's introduce it to the difference between ordinary thermometer: 1, the structure view: bimetallic thermometer is the use of two different metals in the expansion degree of temperature changes of different working principle; Glass is according to the mercury thermometer, alcohol, toluene, etc liquid has obvious physical properties of heat bilges cold shrink. 2, the work scope of use: bimetallic thermometer and the rod of glass liquid thermometer USES similar, but can be used under the condition of higher mechanical strength. L liquid thermometer USES similar, but can be used under the condition of higher mechanical strength. Glass thermometer is usually used for measuring water supply temperature, backwater temperature, economizer exit water temperature, import and export air temperature and air preheater. External standard mercury thermometer has a thick glass tube, rod frame directly on glass tube on the surface, suitable for measuring the temperature of the liquid and gas in the lab. 3, work to see: original bimetallic thermometer is mainly used in industry of element is one with two or more metal laminate composed of multilayer metal together. To improve the temperature measuring sensitivity, is usually made of metal spiral coil shape. Glass mercury thermometer consists of temperature measurement package, expansion tubes and parts such as scale, generally speaking, there are internal standard and external standard ( Also called type) Two kinds. Internal standard mercury thermometer scale divided on thin tube expansion behind milky glass. The plate sealed in the glass with bulb protection shell. In the expansion of the mercury thermometer thin tube inserted into the two wire, when the temperature reaches the rating, the mercury will lead on, due to the effect of current drive control system, or the device sends out sound and light alarm signal.