Bimetallic thermometer inserted into the depth of what are the requirements?

Bimetallic thermometer can be directly measured All kinds of medium temperature between 50 ℃ to 500 ℃, under normal circumstances, to measure the temperature of the medium, requires the bimetallic thermometer heat tube inserted in the measured medium, after being dashboard pointer stable readings, this value is the temperature of the measured medium. So, when we measure the temperature, the bimetallic thermometer inserted depth what are the requirements? Insert depth of bimetallic thermometer needs to pay attention to the two problems: 1. Can't less than 50 mm, longer than 2 meters, the reason is too short will insert depth due to the heat element cannot be fully inserted into the tested medium temperature measurement inaccurate; And if insert depth greater than 2 m, can cause heat loss, resulting in temperature measurement inaccurate; 2. When we consider the length of the insert depth is sure to have to consider whether or not the insertion depth contains the length of the teeth, if it is contains the length of the teeth, the insert depth = the length of the screw tooth + length of the heat pipe; And if the insertion depth does not contain the length of the teeth, the insert depth = the length of the teeth.