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"Thermometer" for a small object

PostPosted: Wed May 07, 2014 11:27 am
by cross
I am looking for an instrument that could measure the temperature of a small soft roundish object about 3 mm long and 2 mm wide (ovoid)? At this point, I am not sure if I want the whole temperature, the temperature at a certain depth, or the surface temperature, but that would not matter a lot as long as I could be consistent. It might not be possible to penetrate the object without damage, so a non-invasive method would be ideal.

Re: "Thermometer" for a small object

PostPosted: Wed May 07, 2014 1:30 pm
by rickj
In measuring the temperature of a tiny object, the entire difficulty lies in the probe. The probe must be small in relation to the object, otherwise it will influence the temperature too much.

The good news is that you may not need a custom design. Omega have a hypodermic thermocouple probe type HYP-0 just 0.2mm in diameter, which seems small enough to do what you need. Use a type K thermocouple for high accuracy at moderate temperatures.

They also have a good range of thermocouple measuring instruments, such as the handheld type HH12B at reasonable prices. The differential HH12B will allow you to conveniently measure the temperature difference from ambient.

If non-contact is a must, you can look at an infrared type such as the HHM290. The snag is that you need to know the emissivity of the target to get an accurate result. If the targets are all of the same type, you could measure the temperature of one with both the probe and the IR, and derive the emissivity from that.

It's cheaper and quicker to buy an off-the shelf instrument if it will do what you want. If this seems not to suit your needs, please get back to us.

Re: "Thermometer" for a small object

PostPosted: Wed May 07, 2014 1:46 pm
by cross
Wow - thanks for the very prompt and helpful reply. I will look into your suggestions - much appreciated. ~Cindy