Allerød, Denmark – Some of the most challenging sensors to calibrate are the sanitary sensors found in the pharmaceutical and food industries. To accurately calibrate these sensors, the technician must place the sensing element in the uniform zone of the temperature calibrator. However, this is often difficult due to the small size of the sanitary sensor.
Image Credit: Ametek STC
AMETEK STC has a solution with the launch of their JOFRA RTC-168 Reference Temperature Calibrator. "We have extensive experience with producing the highest quality temperature calibrators. This knowledge helped us design the new RTC-168, which includes an industry-first innovation and other performance improvements," said Haakon Harslund, Director of Engineering for AMETEK STC in Allerød Denmark.
The RTC-168 features a new well design allowing sanitary sensors with large flanges to get closer to the temperature uniformity zone than before for improved accuracy and faster calibration time. A redesigned sensor basket combined with a temperature equalizer and a faster magnetic stirrer help create an extended temperature uniformity zone for liquid calibrations. With the uniformity zone extended vertically, the sensing element in shorter sensors can now reach it, resulting in improved calibrations.
One difficulty in calibrating sanitary sensors is that traditional bath methods result in inconsistent heat transfer to the flange of the sensor due to liquid flow and level changes. The new RTC-168 temperature calibrator includes a patent-pending calibration technique for liquid calibration of sanitary sensors, allowing operators to replicate in-field use during their liquid calibration – resulting in a sensor calibration that closely matches its day-to-day use.
JOFRA's new design isolates the liquid in the main block from the excess liquid around the flange. This isolation removes the liquid flow effect and the need for a precise liquid level, making it easier to calibrate under multiple conditions. The heat transfer to the flange is handled through the aluminum of the heat conveyor rather than through the liquid, creating a much more consistent transfer. In addition, the heat conveyor optimizes the liquid circulation in the block for the calibration of sanitary sensors.
In addition, the RTC-168 calibrator also features an industry-first reverse flow cooling technique. This technique pushes the hot air out of the bottom of the calibrator rather than the top. This innovation protects the customer's sensor under test from continuous heat increases and provides a safer working environment for the technician.
Image Credit: Ametek STC
The RTC-168 calibrator also includes a new removable liquid container. "The two greatest challenges to using a dry/wet combination calibrator are the cleanliness and time needed to switch from wet to dry and back. We have solved this issue with a removable liquid container. When the customer wants to switch from wet to dry, they now only need to remove a small container, and it's ready to go," said Harslund. The container also includes a screw-on lid with a pressure relief valve, making transporting the calibrator clean and safe.
The RTC-168 is a combination wet bath and dry block temperature calibrator. It features a range from -30°C to 165°C in both liquid and dry. Accuracy of the internal reference is ±0.18°C in dry mode, and up to ±0.14°C in liquid mode. Using the associated external reference sensor, these accuracies improve to ±0.09°C and ±0.06°C respectively. With an excellent stability of ±0.01°C, the RTC-168 is the ideal calibrator for the high demands of the pharmaceutical and food industries.
Haakon Harslund added, “We are very proud of our team’s ability to design and produce this innovative calibrator during such a difficult time. Our team was able to continue to collaborate and creatively design while working from home. The result is a calibrator that we know our customers will appreciate and that we are proud of.”
About AMETEK STC and JOFRA
AMETEK STC manufactures and supplies calibration instruments for temperature, pressure, and process signals under JOFRA and Crystal brands. JOFRA temperature calibrators are known worldwide for their accuracy, reliability, and ease-of-use. For more information, visit www.ametekcalibration.com.