Metal on the surface of the working principle of the thermometer and matters needing attention

Metal surface thermometer is a member of the bimetallic thermometer, its working principle is based on the principle of solid heat expansion, the two pieces of expansion coefficient difference is very big pieces of metal welded together. When the temperature changes, the difference is very big, caused the different expansion coefficient of expansion and contraction, the deformation of sheet metal bending. According to different deformation and produce different momentum, momentum to drive the connection shaft and the other end of the indicating needle, indicate the temperature. Due to the metal surface thermometer is mainly used to measure the surface temperature of the medium, so in order to accurately measure the temperature, we need to pay attention to the two small problems, 1. Is waiting for at least 15 minutes after the measured medium heat, we call the reaction time, usually when the temperature is stable, the measured temperature is accurate; As the temperature dial indicator on the surface temperature of the measured medium. 2. In order to prevent the loss of heat, be sure to keep the measured medium and metal surface thermometer temperature place is clean.