Accurate temperature measurement 1

[Harini Krishna]

Hi
We have an application where we need to measure temperature of the filling in the steel container.
We cannot have a direct temperature sensor placement in steel Container due to application constrains. SO we planned placing it as shown in figure.
Could you please suggest if this type of arrangement would give accurate measurement?
if not, can you suggest a way to place the temperature measurement sensor so that it can read the temperature accurately?

Thankyou

 

[IRstuff]

We cannot have a direct temperature sensor placement in steel Container due to application constrains.

Why not? Please explain. Is this for school?

Is the temperature sensor in contact with the steel container? You've again picked a measurement approach that requires calibration, which will probably cost your more time than if you did it the conventional way.

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[Harini Krishna]

Yes, the temperature sensor is in contact with steel container.
This is not for school.

 

[EdStainless]

What temp range?
What accuracy and precision is needed?
What kind of sensor will you use?
In general the sensor needs to be as light weight as possible without sacrificing durability, and fastened very well to the surface. If using a TC it should be spot welded to the surface, if a TRD it should be glued using a thin adhesive. Then the outer insulation needs to extend over the sensor to minimize local heat loss.

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[georgeverghese]

If you are limited to non contact devices, how about this

https://instrumentationforum.com/t/fluke-radiation-pyrometer/8793

 

[Harini Krishna]

Edstainless
temperature range : 15 to 85 degree C
Accuracy : +/- 1 degree
Precision : 0.5 degree C
as of not we planned to go with digital temperature sensor ( LM75B)

 

[IRstuff]

The part's datasheet say ±2°C over your specified temperature range although it meets the precision

https://www.nxp.com/docs/en/data-sheet/LM75B.pdf

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[EdStainless]

Radiation will never be accurate enough at your temp range. Too little energy to work with. Any little change in surfaces (color, shininess, reflectance, emmisivity) or even in ambient air will impact the reading.
I looked at some rated for -20 to 100C and they were still +/-1C on both accuracy and precision, and you have to figure out how to set the emissivity.

https://www.advancedenergy.com/globalassets/resources-root/data-sheets/en-op-in500-data-sheet.pdf

If you want that accuracy and precision then both values for the sensor will need be better than 0.2C, because you also have the meter to account for.
Use a contact RDT. Typically a 3wire one is used for high precision and stability. You can clamp them in place and use some heat conducting paste and get very good results.

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P.E. Metallurgy