Accurate Verification of Short Temperature Probes
The Challenge
An American manufacturer of animal health care products needed to verify probes in
ultra-low temperature freezers. They had a selection of different temperature calibrators
available for this and for other applications that required temperature calibration and
verification.
However, the manufacturer had problems verifying short probes, 6 to 8 cm (2.5 to 3
inch) in the 0 to 90°C (32 to 200°F) range. The temperature indicated on the temperature calibrator did not match the probes.
The Solution
The manufacturer started using the
JOFRA RTC-156B temperature calibrator, featuring a dual-zone heating feature. This feature allows them to calibrate short sensors that cannot be
fully immersed in the calibration zone. By using the RTC-156B calibrator together with the sanitary sensor calibration kit containing the
JOFRA short reference sensor
STS102A, the manufacturer could now perform calibration of short sensors.
We demonstrated the
RTC-156B and explained the dual-zone heating feature of the
unit. By using the dual-zone heating feature in combination with the short reference
sensor, the manufacturer obtained the high accuracy that they desired even when
calibrating difficult short sensors.
The manufacturer could insert the
STS102A probe at the
same depth as the tip of the device under test and get an exact reading of the two
probes. Having them at the same depth eliminated the temperature error that they were seeing using their old method.
The Benefit
After testing and trying out the JOFRA solution, the difference between the original
verification and the calibration with the RTC-156B was a deviation of 3°C (5°F)
at 54°C (130°F). So when the original device said it was 54°C (130°F) it was actually
51°C (125°F). The JOFRA solution eliminated this error.
You can download the
application note here.