Graphitization Furnace Temperature Measurement System: Infrared vs. The"&"rmocouple, How to Choose at High Temperatures? Generally, dual-color infrared thermocouples have a maximum temperature measurement range of over 3000 degrees Celsius, while thermocouples have a long-term stable operating range of at least 1500 degrees Cel"&"sius. Does this mean that thermocouples are completely useless when the high-temperature graphitization furnace operates at 3000 degrees Celsius or higher? No, our high-temperature graphitization furnace is designed with cascade temperature control, conne"&"cting these two completely different components with different temperature ranges in series, making temperature control more precise.
During the graphitization process, if the temperature measurement is inaccurate, or if the temperature measureme"&"nt is inaccurate due to the influence of smoke, all subsequent parameter settings, automatic adjustments, and quality judgments will lose their basis.
Therefore, the selection and maintenance of temperature measurement systems are matters that every u"&"ser must take seriously. Thermocouples: A classic choice. Thermocouples are selected based on their model. After a period of exploration, once the insulation gradient is accurately determined, they can be used in conjunction with infrared thermometers to"&" achieve higher accuracy in temperature measurement and control. Type B thermocouples (platinum-rhodium 30-platinum-rhodium 6) and Type C thermocouples (tungsten-rhenium 5-tungsten-rhenium 26) are commonly used contact temperature sensing elements in gra"&"phitization furnaces. Their advantages are high accuracy, fast response, and stable reliability. However, their lifespan is drastically shortened above 2500℃. The precious metal wire will evaporate and become brittle at high temperatures, failing after on"&"ly a few cycles. They are suitable for precise temperature measurement below 2500℃ or as a calibration reference.
Infrared Thermometer: Non-Contact High-Temperature Measurement
Infrared thermometers calculate tem"&"perature by receiving infrared radiation emitted by objects. They do not require contact with the object being measured, thus preventing damage from high temperatures. Suitable for ultra-high temperature measurements above 2500℃. Among them, the dual-colo"&"r infrared thermometer is the preferred choice for high-temperature graphitization furnaces—it simultaneously measures the ratio of radiation intensity in two bands, automatically compensates for signal attenuation caused by dust, steam, etc., and has str"&"ong anti-interference capabilities.
Regular Calibration is Essential
Infrared thermometers are precision optical instruments and will drift after a period of use. It is recommended to send them to the manufacturer"&" or a nationally authorized metrology institution for professional calibration using a blackbody furnace every 1 to 2 years.
Between two formal calibrations, a calibrated type B or C thermocouple can be placed inside the furnace and compared on-site w"&"ith the infrared thermometer at approximately 1500℃ to promptly identify potential problems. **Lesson Learned:** A factory's graphitization degree was consistently unstable. After investigation, it was discovered that the infrared thermometer reading was"&" nearly 300℃ lower than the actual temperature. This single deviation caused all automatic controls to malfunction. Inaccurate temperature measurement is like the small nail that spoils the whole barrel. **Article**")
