Message Board Thread - "Thermography in fired heaters"

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Thermography in fired heaters PKS 1/12/2004
When we are doing thermography in fired heaters, we are setting the back ground temperature by taking the wall temperature at e=1 & the box temperature in average mode and we are putting it as Tamb or Tref as per recent news. But reflection also may come from the flame itself besides refractory wall, which we are not taking into consideration. So what will happen to the accuracy of the reading?

In my opinion, why we cannot set the maximum temperature (which is due to flame) observed in the radiation zone as Tamb, because that is also going to be reflected to your camera when you are taking the reading of tube skin temperature.

If any body can help in this regrad,Please...
Many many thanks for the same.

PK
 
re:Thermography in fired heaters Gary Orlove 1/14/2004
You are correct that the flame itself does radiate thermal energy; and it can interfere with the inspection due to its radiant emission as well as its transmission. The best way to minimize both of these effects is to use a camera with a 3.9µm filter. This positions the camera’s sensitivity into a region where the hot gases have excellent transmission and very little emission so you don’t see the effects of the flame transmission or reflection.

Please see the May 2001 InfraMation newsletter at http://www.infraredtraining.com/community/newsletters.asp for more information and specific procedures to use.

Gary Orlove
Infrared Training Center
 
re:Thermography in fired heaters PIOTR 1/14/2004
The way proposed by Gary is of course proper but... often, depending on type of installation and particularly composition of fuel... metrological conditions are much more complex and potential errors of such measurements rather great.
Using technological news of hardware and software together with a new- unfortunately more complex procedure of measurements it is possible to decrease these errors significantly.
Details and examples will be published soon in SPIE Thermosense XXVI-APRIL 04- Proc. paper No 5405-33 and the next on my web page www.pirs.pl.
 
re:Thermography in fired heaters PIOTR 1/14/2004
The way proposed by Gary is of course proper but... often, depending on type of installation and particularly composition of fuel... metrological conditions are much more complex and potential errors of such measurements rather great.
Using technological news of hardware and software together with a new- unfortunately more complex procedure of measurements it is possible to decrease these errors significantly.
Details and examples will be published soon in SPIE Thermosense XXVI-APRIL 04- Proc. paper No 5405-33 and the next on my web page www.pirs.pl.

Piotr Pregowski/PIRS, Pl/
 


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