Pozo de metrología Fluke 9171-D-156

Measure, graph and record three sensor types with one tool

Every once in a while, a new product comes around that changes the rules. It happened when we introduced handheld dry-wells. It happened when we introduced Micro-Baths. Now we’ve combined bath-level performance with dry-well functionality and legitimate reference thermometry to create Metrology Wells.

With groundbreaking new proprietary electronics from Fluke Calibration’s (patents pending), Metrology Wells let you bring lab-quality performance into whatever field environment you might work in. New analog and digital control techniques provide stability as good as ±0.005 °C. And with dual-zone control, axial (or “vertical») uniformity is as good as ±0.02 °C over a 60 mm (2.36 in) zone. (That’s 60 mm!) Such performance doesn’t exist anywhere else outside of fluid baths.

In short, there are six critical components of performance in an industrial heat source (which the European metrology community explains, for example, in the document EA-10/13): calibrated display accuracy, stability, axial (vertical) uniformity, radial (well-to-well) uniformity, impact from loading, and hysteresis. We added a seventh in the form of a legitimate reference thermometer input and created an entirely new product category: Metrology Wells.

(By the way, Metrology Wells are the only products on the market supported by published specifications addressing every performance category in the EA-10/13. Our specs aren’t just hopes or guidelines. They apply to every Metrology Well we sell.)

Metrology Wells are different. Temperature gradients, loading effects, and hysteresis have been minimized to make the calibration of the display much more meaningful. We use only traceable, accredited PRTs to calibrate Metrology Wells and our proprietary electronics consistently demonstrate repeatable accuracy more than ten times better than our specs, which range from ±0.1 °C at the most commonly used temperatures to ±0.25 °C at 661 °C.

An application note is available to help better understand the uncertainties mentioned above. «Understanding the uncertainties associated with the use of Metrology Wells» is available from the Knowledge & Information tab on this page.

For even better accuracy, Metrology Wells may be ordered with built-in electronics for reading external PRTs with ITS-90 characterizations.

What’s more, Metrology Wells actually have these specifications published for each unit, and we stand by them.

For Metrology Wells, loading effects are minimized for the same reasons that axial gradients are minimized. We use deeper wells than found in dry-wells. And we utilize proprietary dual-zone controls. Loading effects are as minimal as ±0.005 °C in the cold units.

Immersion depth
Immersion depth matters. Not only does it help minimize axial gradient and loading effects, it helps address the unique immersion characteristics of each thermometer tested in the heat source. Those characteristics include the location and size of the actual sensor within the probe, the width and thermal mass of the probe, and the lead wires used to connect the sensor to the outside world. Metrology Wells feature well depths of 203 mm (8 in) in the Models 9171, 9172, and 9173. The Model 9170 is 160 mm (6.3 in) deep to facilitate temperature of –45 °C.

All four models come with an RS-232 serial interface and the Model 9930, Interface-it software. All are also compatible with Model 9938 MET/TEMP II software for completely automated calibrations of RTDs, thermocouples, and thermistors.

Even without a PC, Metrology Wells have four different preprogrammed calibration tasks that allow up to eight temperature set points with “ramp and soak» times between each. There is an automated “switch test» protocol that zeros in on the “dead-band» for thermal switches. And a dedicated °C/°F button allows for easy switching of temperature units.

Any of six standard inserts may be ordered with each unit, accommodating a variety of metric- and imperial-sized probe diameters. And Metrology Wells are small enough and light enough to go anywhere.

9171
If you need more depth, the Model 9171 provides 203 mm (8 in) of immersion over temperatures from –30 °C all the way to 155 °C with full-range stability of ±0.005 °C. Just like the 9170, this dry-well has exceptional axial and radial uniformity. The display of the 9171 is calibrated to an accuracy of ±0.1 °C over its full range.

9172
The Model 9172 provides temperatures from 35 °C to 425 °C with a calibrated display accurate to ±0.2 °C at 425 °C. In addition to exceptional accuracy, the 9172 is stable from ±0.005 °C to ±0.01 °C, depending on temperature. With 203 mm (8 in) of immersion, the 9172 significantly reduces stem conduction errors at high temperatures.

9173
For work between 50 °C and 700 °C, the Model 9173 provides unmatched performance. The 9173 has a display accuracy of ±0.25 °C at 700 °C and an immersion depth of 203 mm (8 in). Stability and uniformity performance of this unit are enough to dramatically reduce uncertainty budgets for calibrations of thermometers at high temperatures.

Of course, there’s still a place in the world for dry-wells or “dry block» calibrators. In fact, Fluke Calibration makes and will continue to make some of the best performing, portable, fast dry-wells in the world. There’s still nothing better for a quick test of industrial temperature sensor performance.