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Non-Contact Infrared Thermometer Calibration

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Skye

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Posted 06 September 2012 - 03:35 PM

Can anyone tell me if there is a standard method for calibrating non-contact infrared thermometers, as with probe thermometer checks in iced and boiling water?

Many thanks :thumbup:
Skye


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shea quay

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Posted 07 September 2012 - 09:28 AM

There is a standard method, but unfortunately not involving steam and ice.

I took a sample of one of these years back for taking the temperature of cooked sliced meats. I couldn't justify them from a food safety perspective (they were used for a critical control point, as the sliced meat was too thin to take an internal temperature). The in-house calibration suggested by the supplier involved a specialised hotplate for reasons that now escape me (something to do with the interaction between heat and different metals?). I would advise you to avoid using these type of thermometers at all costs, as they do tend to drift also. We ended up threading a thermocouple through a syringe needle. Created a bit of extra paperwork, wasn't perfect I agree, but at least we could carry out regular internal calibrations.


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KTD

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Posted 07 September 2012 - 02:18 PM

Some lab supply companies (VWR Scientific) offer a 'black body' magnetic sheet. The sheet is placed on a large metal surface away from strong environmental tepmerature fluctuations (file cabinet in the office corner) and allowed to equilibrate. You then 'shoot' the sheet to get a temperature. Some sheets have strip thermometers attached - otherwise, check calibration with a calibration verified thermocouple utilizing a flat surface probe and use it to determine the sheet temperature. Obvious potential for increased measurement errors, but best I have seen so far.


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Charles.C

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Posted 08 September 2012 - 06:53 AM

Can anyone tell me if there is a standard method for calibrating non-contact infrared thermometers, as with probe thermometer checks in iced and boiling water?

Many thanks :thumbup:
Skye


Dear Skye,

There is also a longish thread (this year) here which contains considerable detail on the application / limitations of ir units submitted by an (apparent) expert on the subject. Maybe try a little searching.

Rgds / Charles.C

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Kind Regards,

 

Charles.C


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GMO

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Posted 10 September 2012 - 02:29 PM

I have seen a calibration machine where the reference probe is placed into a hole and the test probe placed into another hole to compare but to calibrate the IR probe, the cover is removed to reveal a hotplate which is meant to be at the same temperature as the probe in the hole. I'm not sure I believe it and I don't believe IR thermometers are ever that accurate but it seemed as good a method as any.


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QLD

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Posted 13 September 2012 - 09:06 PM

I have seen a calibration machine where the reference probe is placed into a hole and the test probe placed into another hole to compare but to calibrate the IR probe, the cover is removed to reveal a hotplate which is meant to be at the same temperature as the probe in the hole. I'm not sure I believe it and I don't believe IR thermometers are ever that accurate but it seemed as good a method as any.


Sounds like the same method but we used one of these and compared against a reference probe : http://www.comarkins...?product_id=214

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Dr Vu

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Posted 13 September 2012 - 09:31 PM

My take
IR thermometer... Throw out old one and buy a new one once the calibration certificate expires; for verification (daily usage) you can use any surface by comparing with a standard calibrated thermometer( usually the IR i gave a plus/mnus 3 deg C)

No auditor questioned my simple methodology..


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A vu in time , saves nine

Charles.C

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Posted 14 September 2012 - 01:24 AM

Dear vulindlela,

No auditor questioned my simple methodology.


They were probably overwhelmed by yr budgetary tolerance. :biggrin:

Rgds / Charles.C

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Kind Regards,

 

Charles.C




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