Bimetallic thermometer principle, structure and use of the instructions

Bimetallic thermometer, the English name for bimetal thermometer, its working principle is to two or more with different expansion coefficient of metal welded together, when the temperature changes, with different pieces of metal expansion degree of this bending of sheet metal. Such as the metal group one end fixed and the other end with a pointer displayed a thermometer because of deflection and instructions. The structure of the bimetallic thermometer is will have different physical properties ( Thermal expansion) The two alloy fuse together into a bimetallic strip. Then the formation of the spiral shape, one of the two alloys, is called for the nickel alloy steel, easily when heated almost devoid of inflation; Another is to use nickel alloy, there are a lot of expansion when heated. The two alloy welding together, run to the thickness of the need, is the bimetallic strip. Bimetallic temperature instructions: 1. Industrial common bimetallic thermometer, the expansion of metal multi-purpose invar steel, this is a kind of nickel 36% nickel and iron. High expansion of metal in relatively low temperature in bronze, nickel in high temperature. 2. To maintain its accuracy, the thermometer should not be in the long time continuous use, in order to prevent the sheet metal to produce elastic fatigue phenomenon. 3. To eliminate the influence of radiant energy, metal shell metal surface should be smooth. 4. Bimetallic thermometer is generally measured temperature in the range of - 50 - 500℃。 5. Bimetallic strip a fixed, the other end around the song, it is proportional to the square around the curvature and temperature is inversely proportional to its thickness.