How to detect the temperature of the metal surface

Can say all areas can use thermometer, bimetallic thermometer is the most common, but with the development of the industry, the surface measurement is a major aspect of temperature measurement. In machinery, metallurgy, energy and defense departments, measurement of the temperature of metal surface are very common. For example: heat treatment of castings, forgings, gas pipes, steam pipes, wall, etc. Various kinds of metal surface temperature measurement of the furnace, the temperature is from dozens of degrees, a few baidu to 1000 degrees, for such a temperature, the most commonly used method is to use direct contact measurement method. It is used in a variety of thermocouple, with adhesives or welding method, thermocouple and direct contact with the metal surface to be tested, then put on the thermocouple received display instrument of temperature measurement system, according to the metal surface temperature. So, how to measure the surface temperature? This time need a thermometer on the surface of, generally speaking, measuring surface temperature of the test cost is higher, here introduce a thermometer produced by instrument surface, it is used in pipes, surface, industrial, petroleum, chemical industry, power plants, Marine and other fields, it is to rely on the double metal heat bilges cold shrink principle of sensors to work, by contact spring or magnet at the bottom of the thermometer to measure the metal surface and reading. This type of double metal thermometer can range from 30 to 500 c, c accuracy can be + / - 3%. For some of the requirements for accuracy is not high occasions, the use of thermometer of cheap is a money and beauty. In addition, the spring type surface thermometer again to pay attention to when using spring length and the diameter to be fixed, because, in order to meet the demands of the guest's measuring equipment, so the surface thermometer can according to need to customize, easy to use.