Our eXacal precision thermocouples are the result of two years‘ development of maximum accuracy temperature standards for Klasmeier’s DAkkS-accredited calibration laboratory.
eXacal thermocouples at a glance:
- Precision thermocouples made from precious metals
- Optimised for calibration to temperature fixed points
- DAkkS-compliant calibration with minimum uncertainties
- Minimum inhomogenity due to heat treated thermowires
eXacal – Klasmeier’s precision thermocouples
Klasmeier is a medium-sized family-run business based in Fulda, Germany. It has been family-owned for more than 25 years and is currently run by qualified engineers Peter and Thomas Klasmeier. The firm specialises in temperature measurement and temperature calibration and also runs Klasmeier Calibration Service.
With its eXacal thermometers, Klasmeier has become a manufacturer that can now offer complete in-house production of thermocouples.
In addition to construction of the thermocouples themselves, the firm also focuses on developing unique tools and production processes. Klasmeier is able to offer end-to-end production of a precision thermocouple in-house. From construction, through production, right up to final DAkkS-compliant calibration, no external suppliers are required other than for the raw materials. This independence guarantees the high quality of our thermometers.
The components required, such as hand grips and prototypes for fine-tuning, are produced by milling, turning and drilling.
Precious metal soldering
Thermowires are soldered by hand to ensure a high level of accuracy. The fuel gases required, namely hydrogen and oxygen, are not stored in bottles, but are generated at the perfect ratio of 2:1 from water using electrolysis. This guarantees the absolute purity of the fuel gases.
Heat treatment of thermomaterials
One of Klasmeier’s core competencies is the targeted heat treatment of thermowires. The three-stage annealing process, which was developed in-house, guarantees that the eXacal thermometers are metallurgically stable and thermoelectrically homogenous.
The eXacal precision thermocouples are used as transfer standards, for precise temperature measurement or as calibration standards. The thermocouples are noble-metal precision thermocouples which can be manufactured in two lengths, with or without a stainless-steel reference junction. eXacal thermocouples can, however, also be used for all other temperature measurements.
Features of eXacal precision thermocouples:
- Heat-treated thermowires
- Measurement junction in ultrapure and gas-tight ceramic shaft
- Copper wire extension cables with low EMF properties
- Maximum possible purity of thermowires
The standard measuring junction of the eXacal precision thermocouple is 600 mm in length, and is thus suitable for temperature fixed points. We also offer an alternative, shorter sheath of 300 mm for industrial use.
Thermocouple reference junction
The reference junction is manufactured from stainless steel as standard, in order to ensure that it can be positioned in a water triple point or 0°C ice/water bath. As alternatives, we also offer models featuring a thermal cable or extension cables with mini connectors.
Our eXacal precision thermocouples are calibrated in Klasmeier’s DAkkS-accredited calibration laboratory (D-K-15224-01-00, accredited in line with DIN EN ISO/IEC 17025:2005). This ensures full, international traceability of the thermometers in terms of the measurement technology. The temperature fixed points used guarantee minimum uncertainties in measurement. A comparison calibration is performed using Pt/Pd and Au/Pt calibration standards:
- Minimum measurement uncertainties with DAkkS calibration certificate
- Temperature fixed points of water at 0.01°C up to silver at 961.78°C
- Pt/Pd and Au/Pt standards for comparison calibration
DAkkS-permitted uncertainties in respect of eXacal precision thermocouples
The eXacal precision thermocouples have been designed for fixed-point calibration up to the silver point (961.78 °C). They can, however, also be calibrated using the comparison method.
Comparison-calibrated eXacal precision thermocouples are calibrated on the basis of platinum/palladium or gold/platinum thermocouples. The maximum calibration temperature is 1200°C. The calibration furnace is a high-temperature furnace with several heating zones and a customised equalising block.