Length of the thermocouple in the combustion furnace
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There is a horizontal combustion furnace, and due to the extremely high temperature in the furnace, the thermocouples often get damaged. After discussion, it was decided to use shorter thermocouples; previously, these thermocouples were 7–9 centimeters away from the furnace wall, but now shorter thermocouples will be used, with a distance of 3–4 centimeters from the furnace wall. Will the temperature change as a result of using shorter thermocouples? Will the measured temperature be lower than before? Please share your thoughts, thank you, extra points!
It is 3-4 centimeters away from the furnace wall, so it should have no impact.
The transmission speed is slow, which means it’s low. What’s the temperature? Is it 1500?
Reducing the depth of penetration of the thermocouple by half will lead to inaccurate measurements and lower temperatures; please do not attempt this. Thermocouples often get damaged; in principle, their insertion length should not be shortened. It is advisable to consult several different manufacturers, taking into account the temperature resistance and strength of the protective tubes. Currently, there are protective tubes for high-temperature and wear-resistant thermocouples, but few manufacturers produce them, and their prices are also relatively high.
Hello, could you please explain in detail what kind of fuel is used in your furnace? What type of thermocouple is being used currently? Also, what does it mean when they burn out frequently – is it the protective tube that’s damaged, or the thermocouple element inside? Our company specializes in the production of thermocouples, thermal resistors, and bimetallic thermometers.
If, under the original design conditions, the flame touches the casing, it can be shortened; otherwise, it is not recommended to do so, as it is just deceiving oneself.
This post was last edited by Pandora on 2017-11-11 09:32. We have had cases of modifications. It has no impact. The furnace temperature is around 900°C, with an insertion depth of 1200 mm. It also often warps from heating. Later, we made a cartridge-type one. Not all are locked tight. Telescope thermometer for use while driving. Temperature measurement has no impact. Then it was locked at an insertion depth of 500 mm, and it has been in use ever since! Other devices are ready to directly change the length of the thermometer.
Temperature-induced damage is mostly due to selection and installation issues, rather than fundamental problems
Reducing the length from 7-9 cm to 3-4 cm will have little impact on the measurement results under the same temperature conditions; on the contrary, it will extend the lifespan of the thermocouple protection sleeve. If possible, it is better to install the thermocouple vertically.
I’m not sure whether \"burned out\" refers to the casing losing sufficient strength due to high temperatures, or to it being damaged by erosion near the furnace wall Or other situations. In the first case, when the temperature difference inside the furnace is not significant, reducing the insertion depth doesn’t have much significance, unless it is in a critical state; in that case, reducing it slightly will bring it within the range where the strength can still be maintained ； In the second case, it also has little effect unless it is retracted into the furnace wall. Therefore, it can only be analyzed based on the specific circumstances.