Pyro Optical Pyrometer by The Pyrometer Instrument Co. - Model/Type?

[Shane]

A friend has just given me a beautiful 1960-ish optical pyrometer. It is a Pyro Optical Pyrometer, made by The Pyrometer Instrument Co. with serial number 14081. Cannot find model or type.

Now. To the questions.

Does anyone know how this thing works? The physics I understand slightly, as in matching the intensity of a filament inside the pyrometer and comparing it with the intensity of the source to be measured. But what do these crazy knobs do?

- There is a switch knob with one position marked N and the other marked 3. Does anyone know what this does?

- Another switch marks High, Mid, or 0. This I know changes the intensity of a red filter. Why? Simply for looking at brighter sources?

- Is the intensity of the filament variable?

Does anyone know anything about these very antiquated (yet amazing) devices or know anywhere I can find out more about them? Of course I have googled them as well as checking out the Pyro brand website but can't seem to find enough definitive information about them. I was hoping one of you fine scholars and archivers of knowledge had come across this particular pyrometer and may have had the chance to work with one.

Any info helps.
Shane

Also if pictures are needed this is exactly what mine looks like:
http://hivaceq-amci.com/opticalpyro.jpg

This might also be informative (not very informative to me however)
http://www.pyrometer.com/PDF_files/Optical.PDF

 

[Redbelly98]

There is a brief description of operation at the bottom of page 1 here:
http://www.pyrometer.com/PDF_files/Optical.PDF
It looks pretty much like the same model you have. You could always try calling the company (phone # is in .pdf document above), and ask for tech support or if they can provide a full user's manual.

From the limited times I used a pyrometer in the 1980's, here is what I remember:

You should be able to look through the pyrometer so that both the internal filament and external object (that you want the temperature of) are visible.

One knob will adjust the brightness of the internal filament; you adjust it until the filament "disappears", i.e. is just as bright as the external object. If the filament is too low, it appears darker than the object; if too high, then it will appears too bright.

There should be a way to get a temperature readout based on how bright you have adjusted the filament to be.

There might be a way to adjust the reading to compensate for the emissivity of the external object, if known.