What is the amazing temperature sensing ring for calibrating the temperature in high-temperature furnaces?
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At work, I often hear the experienced workers say that the temperature inside the furnace needs to be calibrated regularly, and for this purpose a special device called a temperature sensing ring is used; it’s said that this ring allows the temperature to be calibrated as soon as it goes in and out. I’ve always been curious about this, and it’s also confusing. I have not seen this miraculous artifact with my own eyes; I can only guess and understand it. It wasn’t until yesterday that I understood: the internal temperature control for a certain device requires around 1600°C. At such high temperatures, any precision instrument would be reduced to ashes. From this, it can be inferred that this circular device must be quite simple – just a round object. What remains is the issue of the material used; why choose this particular material? I then thought about whether the principle of thermal expansion and contraction might be at play. Since thermal expansion occurs, this component must be disposable, as it cannot be used again after once being used. Under normal conditions, common materials expand when exposed to high temperatures, resulting in an increase in volume. Therefore, it can be inferred that this device must have been precisely manufactured, as the degree of deformation at high temperatures is certainly very small. The materials can only be ceramic or metal; organic materials will definitely turn to ashes at high temperatures. Ceramics can withstand high temperatures. From what I know, ceramic materials are hard and brittle, with little change under high temperatures. It has to be metal. But what kind of metal? Which metal would exhibit such an exact linear or nonlinear relationship between temperature and rate of expansion? This is the first point of confusion. The second confusing point is regarding entry and exit from the furnace: is melting and deformation required, or is it just thermal expansion and contraction? How can thermal expansion and contraction be measured, since it might contract again after being taken out, making the measurements inaccurate?
Could the expert explain in detail what the specific requirements are, how to proceed with it, and of course, the principle behind it? Thank you
Thank you again; I look forward to the expertise of the Instrument Master to guide me.
Regarding #2, it refers to a zirconia analyzer; temperature measurement is a different concept. I don’t know how to use an analyzer to calibrate temperature instruments.
The name of the measuring instrument is a temperature measurement ring; I haven’t actually used it before, and I’d like to communicate with experienced technicians in order to improve together.
As the original poster said, ceramic temperature probes are those that are used most often. The working principle of the ceramic temperature sensing ring is based on its linear contraction within the operating temperature range; when heated in a furnace, it contracts, and continues to contract at the highest temperature as the holding time increases. Within the operating temperature range, the shrinkage rate is linear; the decrease in ring diameter can be measured using a digital micrometer, and the test temperature can be determined by referring to a conversion table.