To understand the classification and principle of the thermometer - together Shanghai dragon instrument electric appliance co. , LTD

According to the using purpose of distinction, has been designed and manufactured by a multitude of thermometer. Its design according to: application of solid, liquid and gas is influenced by temperature and heat bilges cold shrink phenomenon; Under the condition of constant volume, gas ( Or steam) The pressure due to the difference between the temperature transformation; The role of thermoelectric effect; Resistance with temperature of transformation and transformation; The influence of thermal radiation, etc. Gas thermometer: multi-purpose hydrogen or helium temperature material, as a result of hydrogen and helium liquefaction temperature is very low and close to absolute zero, so its temperature range is very wide. The accuracy of the thermometer is very high, for more precise measurement. Resistance thermometer: divided into metal resistance thermometer and semiconductor resistance thermometer, is based on the change of resistance with temperature of the properties. Metal thermometer mainly useful platinum, gold, copper, nickel and other pure metal and rhodium iron, phosphor bronze alloy; Semiconductor thermometer mainly used carbon, germanium, etc. Resistance thermometer use lunch, has been widely used. Its measurement range for - Around 260 ℃ to 600 ℃. Thermocouple thermometer: it is an in general use in industrial temperature measurement instrument. Application of thermoelectric phenomena. Together to form two different kinds of metal wire welding work side, the other two ends connecting with measurement instruments, constitute a circuit. Work the end on the measured temperature, end and free end temperature is not at the same time, will present the electromotive force, so there is a current through the loop. After electrical signal measurement, application of temperature is known, will be able to measure the temperature of the other. It is suitable for large temperature difference between the two substances, used in high temperature and low turbidity measurement. Some thermocouple can measure up to 3000 ℃ high temperature, some can close to absolute zero temperature. Pointer thermometer: is like dashboard thermometer, also calls the thermometer, used to measure at room temperature, is made of metal principle of heat bilges cold shrink. It is a bimetallic strip as a temperature sensing element, is used to control a pointer.