Emissivity makes a temperature difference for infrared thermometers.
In the YouTube video below, Frank Liebman, an engineer with Fluke Corporation's Hart Scientific Division demonstrates the impact that surface emissivity has on temperature measurement and temperature calibration using a modified Fluke blackbody calibrator and Fluke Thermal Imager.
We were surprised to see that no one commented on this video, despite an ending that leaves one hanging, at least us, with the obvious question: How do you do a radiometric calibration of a surface of unknown emissivity using a Fluke Blackbody Calibrator?
Do you have any ideas?
1 comment:
I hope I haven't misinterpreted your question but am not quite sure.
I assume this Fluke device has an emissivity very near 1.000 and an accurate T reading. Set your IR thermometer's emissivity to 1.0 and make the instrument calibration with the Fluke. Then measure the temperature of some strong emitter, say flat black paint or graphite with a regular (good) thermometer. Adjust the emissivity on your IR thermometer until the IR temperature reading matches that of the regular thermometer--this is the approx. emissivity of the black material. Then coat part of the surface to be measured with the black stuff, allow it some time to come to same temp as material underneath, and take an IRT reading. Then take another reading on a non-coated part of the surface. The temp ratio (in K, uncoated/coated) X (emissivity of the black stuff) should then represent the emissivity of the surface in question.
I think!
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