How many kinds of thermometer, work principle, respectively is what?

Common with double metal thermometer thermometer, pressure type thermometer, electronic thermometer, temperature and pressure, the surface and the glass rod thermometer, etc. 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 - 80℃- 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, indicates that the change in temperature on the dial. Due to the temperature sensing element has a linear relation with temperature changes, so the location of the bimetallic thermometer pointer indicated is measured temperature value. Pressure type thermometer thermometer is based on closed system internal work material volume or pressure change with the temperature change and the principle of work. Instrument closed system composed of bulb, capillary and elastic element, wen bags as working medium, when measuring temperature, insert the bulb of the measured medium, affected by the medium temperature, temperature package internal working medium volume or pressure changes, the capillary pass this change to the elastic element ( Such as spring tube) , components elastic deformation, displacement of the free end, with the aid of transmission mechanism, drive the pointer indicates the temperature value on the dial. Electronic thermometer thermometer compared with traditional thermometer, digital tube display output temperature, has reading convenient, accurate temperature stability, high precision, wide measurement range, and the advantages of low energy consumption, very suitable for daily temperature measurement. Most of the digital thermometer is the temperature sensor using temperature sensitive element ( Such as platinum resistance, thermocouple, semiconductor, thermistor, etc. ) , will change with the temperature change and physical parameters, such as inflation, resistor, capacitor, thermoelectric emfs and magnetic, frequency, optical properties, such as through the change of temperature sensors into electrical signals, such as the change of the voltage and current, the temperature change and the change of the electrical signal has A certain relationship, such as linear, curve relationship, such as electrical signals are amplified circuit is enlarged to produce suitable for AD converter convert electrical signals, after analog-to-digital conversion circuit which USES A/D converter converts analog signals to digital signals, digital signals to drive circuit output, and then through the display unit, such as digital tube or LCD display, this completes the basic function of measuring temperature digital thermometer. High water meter high water meter is also called a body surface temperature and pressure, can measure pressure, and temperature can be measured, a table is multi-purpose. Is suitable for various kinds of heating system, which can be read out at the same time, pressure and temperature. On the choice of thermal material, which has two kinds of copper and stainless steel. If need products have good thermal conductivity, it is recommended that the choice of copper; For corrosion resistance and alkali resistance, choose stainless steel is recommended. Choose the Psi pressure measurement unit, Kg/cm2, Kpa, Bar, FeetH2o, mmHg, other units need to be customized; Select temperature measuring unit, ℃, ℉, ℃ & amp; ℉. Glass rod thermometer thermometer glass rod by a liquid glass bulb, heat, capillary and scale and safety package of five parts. When the measured medium, put a thermometer in heat in thermal fluid volume expansion in heated, thermal fluid in capillary height will vary with different temperature being measured, which can be read on the scale of measured temperature value.