Common bimetallic thermometer is made according to the principle of what?

The thermometer, it is the floorboard of the temperature measuring instrument, can accurate judgment and measuring temperature. Today we say one of its main category - Bimetallic thermometer, it is mainly used for industrial equipment, petrochemical industry, hvac equipment, ventilation equipment, pipeline equipment, and home, etc. , so common bimetallic thermometer is made according to the principle of what? Commonly used double metal thermometer its principle is to round shape into threaded heat bimetallic strip as thermal devices, and put it in a protective sleeve tube, one end is fixed, known as the fixed end, the other end of the connection on a thin diameter, called the free end. On the free end line diameter is equipped with a pointer. When the temperature changes, the resulting thermal devices the free end of the rotation, drive the change from the Angle of the pointer to the fine diameter, corresponding temperature indicator on the dial. According to the need of the actual installation, bimetallic thermometer can make radial, axial and universal type.