If the reason you don’t use fixed-point cells is because they’re too expensive or too difficult to use, you haven’t heard of Hart’s mini fixed-point apparatus.
The triple point of water (0.01 °C) is one of the most important temperatures on the ITS-90. Unfortunately, realizing and maintaining triple point of water cells hasn’t always been convenient or cost-effective.
Because ITS-90 calibrations require frequent measurements at the triple point of water, and because the triple point of water is often used as a statistical check against the drift of a temperature standard, it is important to be able to realize and maintain well-constructed triple point of water cells easily.
Hart’s 9210 TPW Maintenance Apparatus provides built-in programming for the simple supercool-and-shake realization and maintenance of our 5901B Mini TPW Cell. Simply insert the cell, enter the “freeze” mode through the front-panel buttons, have your morning cup of coffee, and when the 9210 audibly alerts you, remove the Mini TPW Cell and give it a shake to initiate freezing a portion of the water. Re-insert the cell, change the program mode to “maintain,” and you’ve got 0.01 °C for the rest of the day with uncertainty of only ±0.0005 °C.
Precision-machined thermal blocks can also be used to take advantage of the excellent stability and uniformity of the 9210 for performing comparison calibrations. Multi-hole and custom blocks are available with 178 mm (7 in) depths.
–10 °C to 125 °C
Ambient Operating Range
5 °C to 45 °C
±0.05 °C over 100 mm at 0 °C
6–10 hours, typical
0.01 ° (0.001 ° in program mode)
°C or °F, switchable
171 mm (6.75 in) in optional comparison block
15 minutes nominal
3 wells (for 3.18, 6.35, or 7.01 mm probes [0.125, 0.25, 0.276 in])
Adjustable software cutout using control probe; separate circuit thermocouple cutout for maximum instrument temperature
Three multi-hole blocks, blanks, and custom blocks available
Well-to-Well Gradient (in comparison block)
Ambient to 100 °C: 45 min.
Ambient to –5 °C: 25 min.
115 VAC (±10 %), 60 Hz, 1.5 A, or
489 x 222 x 260 mm (19.25 x 8.75 x 10.25 in)
7 kg (15.5 lb.) with block