Good introduction to fixed-point calibration
User friendly and inexpensive
Hart’s 9260 Mini Fixed-Point Cell Furnace provides a fixed-point system that cuts in half the financial investment required to do fixed-point calibrations and virtually all the time and training required by traditional systems.
This furnace costs less than half of a large furnace and works with indium, tin, zinc, and aluminum cells to cover all ITS-90 fixed points from 156.5985 °C to 660.323 °C. The cells themselves, using a smaller volume of 99.9999 % pure metal, also cost much less. But cost is only a part of the issue.
The 9260 makes using fixed points easy. Simply insert the cell at the end of the day and let it sit overnight. The next morning, initialize the built-in software routine for your specific cell. Come back in an hour, verify the stability of the cell, and you can take measurements for the rest of the day from a near-perfect temperature source!
The built-in software lets you choose between using melting-point curves or freezing-point curves for each metal. The ITS-90 calls for freezing points, but melting points are easier to realize, and the difference in uncertainty (less than 2 mK for most applications) is generally insignificant. In fact, the difference between using traditional cells at their freezing points and Hart’s mini cells at their melting points is not significant for most labs in most applications.
Comparison blocks are also available for the 9260 for high-precision comparison calibrations at high temperatures. Two blocks are available with a variety of pre-drilled wells in addition to blank or custom blocks. Well depth is 229 mm (9 in).
50 °C to 680 °C
Ambient Operating Range
5 °C to 45 °C
±0.03 °C to 300 °C
±0.05 °C above 300 °C
Top and bottom zones adjustable by offset
6–10 hours typical
°C or °F, switchable
229 mm (9 in)
15 minutes nominal
Sensor burnout and short protection, over-temperature thermal cutout
±0.2 °C to 300 °C
Two multi-hole blocks, blanks, and custom blocks available
Well-to-Well Gradient (in comparison block)
1.25 hrs. from 25 °C to 680 °C
10.5 hrs. from 680 °C to 100 °C
115 VAC (±10 %), 60 Hz, 11 A, or
489 x 222 x 260 mm
20.5 kg (45 lb.) with block