Help identifying unknown mystery device

[PeterFW]

Hello everybody!
In another forum someone asked if anybody knows what this is, it is the only picture he posted:

https://i.reddituploads.com/ce1170fa0ba143d493b1f8913e71eefe?fit=max&h=1536&w=1536&s=589725836e4ac90f155c2e066b63fb1d

My best guess so far, thermocouple meter with calibration function/output.
Maybe someone here knows what it really is.

Greeting,
Peter

[PedroDaGr8]

According to the internet Foster Cambridge PP332 is a portable potentiometer 20/60mV. It looks more or less identical to this one. In this case, potentiometer I think is the British meaning which is a device which measures electrical potential (ie voltage). It looks to be a null voltage model. I guess the temperature aspect is to account for temperature driift.

[DTJ]

Pedro beat me to it!

https://www.google.com.au/search?q=thermocouple+bridge&safe=off&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjqq62_7pDMAhUlhqYKHdswCJ8Q_AUIBygB&biw=1920&bih=939#safe=off&tbs=ic:color%2Citp:photo&tbm=isch&q=thermocouple+potentiometer+instrument


Edit - the note on the lid appears to suggest it was used in a plant that heat treated metals.

[SeanB]

You use this to calibrate thermocouple indicators, giving an accurate voltage that corresponds to a set temperature less the cold junction voltage. Dual use as you can also use it to set the loop resistance for use with said meter, adjusting a variable resistor to set the resistance to a predetermined value with a cold thermocouple. While you could also use it to read the thermocouple using the null meter that was really just used as a test of the thermocouple. Only time you really used that was in the calibration or verification of the unit against a more precision reference voltage source.

[uncle_bob]

Hi

Back in the days that factories were full of temperature controls based on thermocouples, these boxes were *very* common. At least a couple of dozen companies made them. Keeping a machine so it ran at the right temperature might have involved multiple calibration passes each year. If shutting down the machine meant $$$ wasted ... you bought multiple calibrators and a crew of people did the calibration in a day rather than one guy doing in in a couple weeks.

There are a lot quicker / better / easier / cheaper ways to do it today. You see a *lot* of those gizmos on the auction sites. Generally they are dirt cheap compared to what they once sold for.

Bob

[PeterFW]

Hello and thank you everybody,
now i can sleep peacefully without beeing bothered not knowing what it is!

Greetings,
Peter