What factors will affect the use of bimetallic thermometer?

Bimetallic thermometer is a kind of special measure - 50 - 500 cf field temperature instrument. Its working principle is to put 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. In the process of use, we will find that the same purchase thermometer, use life is very different. Today we speak of what factors will affect the use of bimetallic thermometer. 1. The influence of the installation position. When the normal installation position forward, backward, left, and 90 ℃, change the value of the thermometer should not be greater than the absolute value of a fundamental error. 2. The influence of environment temperature. Thermometer in the specified range of environment temperature, the temperature is 10 ℃ per change, change the value of the thermometer should not be greater than the absolute value of the basic error limits 1/2. 3. The influence of environmental relative humidity. Thermometer should be able to withstand the temperature of 40 ℃ & plusmn; 2 ℃, relative humidity of 91% to 95% ( Electric contact thermometer is 80% to 85%) The humidity test, after 48 h. After test, the value of the thermometer changes should not be greater than the absolute value of the basic error limits 1/2.