Why the insert depth of bimetallic thermometer so important?2

Bimetallic thermometer is a kind of measuring instrument in the field of low temperature detection, it can be directly measured various - in the process of production 40℃- + 500 ℃ within the scope of liquid, steam and gas medium temperature. So its wide application, industry, petroleum, chemical, heating system, pipeline, water heaters, heat preservation box, etc. We all know the bimetallic thermometer is mainly used to measure the temperature of the measured medium, so the accuracy is very important. Actually the bimetallic thermometer inserted depth and precision are equally important. Because even though its accuracy is very accurate, but the insertion depth is wrong ( Improper use) , is also unable to measure the accurate temperature. Usually inserted depth of influence factors of bimetallic temperature there are two. The first is the range of measuring temperature, because the measuring temperature range determines the double the length of the metal sensors ( Double metal sensors installed in the bottom of the heat pipe) 。 In general, from heat tube end, at least 40 mm, that is the length of more than 40 mm is ok. The second has to do with bimetallic thermometer installation, for example, the said pipe with WSS series bimetallic thermometer, or if the connection pipes installed base flange, etc. , to count the length of these parts are.