Temperature difference thermometer for measuring vertical temperature gradients and precise temperature measurement.
Temperature difference thermometer
Pt100 Model D
(-100 °C … 250 °C)
The thermometer for temperature differential measurement is a practical tool for daily laboratory work. The thermometer makes work easier for:
- Measuring of vertical temperature gradients
Vertical temperature gradients must be measured as part of the measurement uncertainty of a calibration (e.g. according to DKD-R 5-4 “Calibration of block calibrators”, DKD-R 5-3 “Calibration of thermocouples” or DKD-R 5-1 “Calibration of resistance thermometers”). - Optimising of calibration furnaces
When optimising heating zones on calibration furnaces, such as the 3-zone high-temperature calibration furnace or the Medusa calibration furnace, precise temperature differences must be measured. - Precise temperature standard
The main measuring point of the differential thermometer is identical to the design of the eXacal PT 100 M and can be calibrated with the same measurement uncertainties. This means that the differential thermometer can be used not only for measuring temperature differences but also as a temperature standard.
The differential thermometer has two Pt 100 temperature sensors positioned at the bottom of the thermometer and at a distance of 4 cm.

Schematic representation of the differential thermometer
Uncertainty of Measurement
eXacal thermometers can be calibrated in our own DAkkS calibration laboratory. The DAkkS accreditation ensures that all calibrations are traceable to national and international standards.
The calibration of the eXacal resistance thermometers is made at ITS-90 fixed points. It is also possible to make calibrations according to the comparison method in calibration baths and calibration furnaces. The measurement uncertainty is calculated from many components. The largest contributions are reproducibility, ITS-90 characteristic, self-heating and hysteresis.
With the differential thermometer, the main measuring point is calibrated at fixed temperature points. The second measuring point is measured by a differential measurement at maximum immersion depth in a heat pipe with an extremely good vertical profile.
- Small Measurement uncertainties with DAkkS calibration certificate
- Temperature fixed points from mercury -38,8344 °C to tin solidification point 231,928 °C
- Differential measurement in a heat pipe / heat pipe furnace
Bereich | Verfahren | Messunsicherheit |
---|---|---|
-38,8344 °C | Mercury triple point | 6 mK |
0,01 °C | Water triple point | 6 mK |
29,7646 °C | Gallium melting point | 6 mK |
156,5985 °C | Indium melting point | 10 mK |
231,928 °C | Tin solidification point | 11 mK |
The measurement uncertainties given are k=2, include an ITS-90 characteristic curve and are specified for the corresponding range.
Model | eXacal Pt100 D |
---|---|
Temperature range | -100 °C bis 250 °C |
Nominal resistance | Pt100 (100 Ohm) |
typical annual drift | 2,5 mk |
Connection type | four-wire |
Connection | Banana plugs or depending on configuration |
Sheath material | metal |
Dimensions | |
Handle | ∅ 20 mm x 100 mm |
Diameter | 6 mm |
Length | 400 mm |
Connection Cable | 2 m |
Measuring resistors / Temperature sensors | |
R0 | 100 Ohm ± 0,05 Ohm (High-Temperature Measuring resistors) |
Alpha | 0,003850 ± 0,000005 |
Norm | IEC 60751:2008 |
Length | 6 mm |
Recommended measuring current | 1 mA |
Self heating | 30 mK @ 1 mA at 29,7646 °C (Gallium-meltingpoint) |
Calibration (Main measuring point) | |
Fixed point calibration | 6 mK bis 11 mK |
Comparison calibration | 10 mK bis 25 mK |
Questions about Thermometers?