As a commonly used heating equipment in laboratories, accurate temperature control is the basis for ensuring accurate experimental results. However, during use, it is inevitable that the laboratory furnace will produce temperature errors due to operation or other reasons, resulting in inaccurate experimental results. So what are the reasons for temperature errors in laboratory furnaces?2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere Furnac
2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere Furnac
The laboratory furnace uses thermocouples for heating and temperature control instruments for temperature control. Generally speaking, the main components that produce temperature errors are thermocouples and temperature control instruments, and the reasons for their errors are different.2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere Furnac2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere Furnac1. Reasons for thermocouple errors2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere Furnac2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere Furnac(1) The instability of thermocouples refers to the changes in the graduation value of thermocouples due to different usage time and usage conditions. In most cases, it may be the main cause of inaccuracy, and the factors causing instability include: volatilization, oxidation, reduction, embrittlement, crystallization, and contamination of thermocouples at high temperatures.2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere Furnac
2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere Furnac
(2) If the thermocouple is made of a homogeneous conductor, its thermoelectric potential is only related to the temperature at both ends. If the thermocouple material is not uniform and the thermocouple is in a temperature gradient field, the thermocouple will generate an additional thermoelectric potential, the size of which depends on the temperature gradient distribution along the length of the thermocouple, the uneven form and degree of the material, and the position of the thermocouple in the temperature field.2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere Furnac
sliding tube furnace2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere Furnac
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2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere Furnac
2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere Furnac
(2) The thermoelectric potential generated by the thermocouple is not only related to the temperature of the measuring end, but also to the temperature of the cold end. Only when the temperature of the cold end is constant, the thermoelectric potential is only related to the temperature of the working end. Most instruments have cold-end temperature compensation. If the ambient temperature of the instrument does not change much, the error caused by cold-end temperature compensation can be ignored. However, when the ambient temperature changes greatly, the instrument cannot fully compensate for the cold-end temperature, so a certain error will also be introduced. For type B thermocouples, since the thermoelectric potential is less than 3μV in the range of 0~50℃, temperature compensation is not required.2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere Furnac
2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere Furnac
(3) It can be seen from the thermocouple graduation table that the thermoelectric potential output by the thermocouple is very small. In order to achieve more accurate measurement, in addition to improving the precision of the measuring instrument, an external amplifier circuit must be added, which will also introduce errors.2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere Furnac2WfMuffle Furnace,Tube Furnace,Vacuum Furnace,Atmosphere FurnacIn summary, the main reason for the error of the laboratory electric furnace is the accuracy of the heating and temperature control system. In order to solve this error, in addition to regular calibration, it is more effective to select high-precision and durable components.
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