Hi, Randall, Arvid & others,
Thanks for the links. I've seen & read Omega's ads (including their
Dilbert comics) for years. Just never looked at their detailed info on
infrared thermometers. In fact, their "low-cost" meter ($85) specifically
lists the emissivity as 0.95.
Your statement "it's my belief that most casual users are unaware of the
problem" would have applied to me until this discussion. So my thanks to
you and everyone else who chipped into the discussion for the enlightenment.
And Arvid - yes you hit it right on the head with "Therefore it would be
reasonable to conclude that if you are using a
non-tunable meter and are measuring items with emissivity values that
deviate far from .95 then the reading that you get are suspect."
Now if I can ever stretch the tool budget to include one of these I
should be able to use it correctly.
Mark
----- Original Message -----
From: "Randall" <tr3driver@ca.rr.com>
>> NOTE: Randall, I'm not doubting on your statement - I
>> have no basis to know either way!
>
> No need to take my word for it, Mark. For example, here is a white paper
> from Omega Engineering (a well-known vendor of industrial process
> measuring
> equipment) that talks about it:
> http://www.omega.com/prodinfo/infraredthermometer.html
> "Some polished, shiny metallic surfaces, such as aluminum, are so
> reflective
> in the infrared that accurate temperature measurements are not always
> possible."
>
> Here's another:
> http://tinyurl.com/yv9hsz
> "Infrared thermometers will have difficulty taking accurate temperature
> measurements of shiny metal surfaces unless they can adjust for
> emissivity."
> Logically, it's like trying to determine the color of a mirror.
>
> And while Tony apparently knows his IR thermometer "won't work" on shiny
> metal, it's my belief that most casual users are unaware of the problem.
>
> Randall
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