What kind of thermometer to detect the surface temperature?

Temperature is a familiar term, especially in the summer, all eyes are on the change of temperature, but some work area whether spring, summer, autumn and winter, all the time to focus on the change of temperature, people according to the needs of different areas and to detect temperature, the thermometer is required to help this time, so what kind of thermometer can satisfy most needs? The most commonly used is the bimetallic thermometer, you can use the every field, very easy to use! But recently, in areas such as pipe using met a big problem, is how to measure the temperature of the surface? Below for everyone to say a recent the most commonly used thermometer, the thermometer can solve a lot of a problem, it is the spring surface thermometer! It 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. 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.