Maximum Accuracy for Your Calibrations
with Temperature Fixed Points according to ITS-90*
Instead of comparing a thermometer to be calibrated with another calibrated thermometer (comparison calibration), fixed-point calibration directly calibrates the test thermometer with a temperature fixed-point cell.
Temperature fixed-point cells are used to calibrate thermometers with the highest precision. They are based on the phase change of a pure substance. At higher temperatures, pure metal temperature fixed points are installed in the apparatus of a calibration furnace, into which a thermometer is inserted. While the fixed-point material in the temperature fixed point melts or solidifies, the temperature remains constant, allowing thermometers to be calibrated on this so-called “plateau.”
These temperature fixed points are defined in ITS-90*.
They provide a reliable reference to in various applications and industries accurately calibrate thermometers.
Whether in calibration laboratories, research environments, or quality control processes – these specialized temperature fixed points play a crucial role in ensuring the precision of your measurements.
*The International Temperature Scale of 1990 (ITS-90) is the globally recognized temperature scale introduced by the International Committee for Weights and Measures (CIPM). It serves as a global standard for precise temperature measurements and is based on the concept of thermodynamic temperature. The ITS-90 uses various precisely defined temperature fixed points and interpolation methods to determine temperatures. Temperature fixed points are the temperatures of phase transitions of certain substances, such as freezing or triple points.
Large and Slim Temperature Fixed Points
from ISOTECH
ISOTECH temperature fixed points are available in two different designs: large and slim temperature fixed points.
The large temperature fixed points are highly accurate and offer the smallest measurement uncertainties. They are the ideal choice for precise applications.
A more cost-effective alternative is slim temperature fixed points. They are more compact and faster. This makes them a more economical solution for fixed-point calibration of thermometers.
Temperaturfixpunkt Wasser-Tripelpunkt-Zelle
Temperatur-Fixpunkt Gallium-Schmelzpunkt
Temperatur-Fixpunkt Quecksilber-Tripelpunkt
Temperatur-Fixpunkt Kupfer Erstarrungspunkt
Temperatur-Fixpunkt Silber-Erstarrungspunkt
Temperatur-Fixpunkt
Indium-Erstarrungspunkt
Temperatur-Fixpunkt
Zinn-Erstarrungspunkt
Temperatur-Fixpunkt
Zink-Erstarrungspunkt
Temperatur-Fixpunkt
Aluminium-Erstarrungspunkt
See our calibration furnaces for commissioning ITS-90 temperature fixed points here:
Safety and Efficiency in
Temperature Fixed-Point Calibration with ISOTowers
ISOTowers are very robust and easy to operate. As they are a combined device with the temperature fixed-point cell permanently installed, it is no longer necessary to handle a delicate temperature fixed-point cell.
In the patented ISOTowers, the temperature fixed points and the heat pipe have been combined into a simple solution for the fixed-point calibration of thermometers. ISOTowers are a more cost-effective and space-saving alternative to using large heat pipe furnaces with temperature fixed-point cells.
Calibrated System in a Single Device
Temperature Fixed Points Do Not Need to Be Installed and Removed
Operation is straightforward
Maintenance Furnaces for Temperature Fixed-Point Cells
ITS-90 Fixed Points Available 24 Hours with ISOTowers
The maintenance bath was specifically designed to commission and maintain up to four water triple point cells over extended periods. It has been in use in the world’s leading national laboratories for over 35 years.
Advantages of the Maintenance Bath:
Safe operating range – 0.3 °C to +0.3 °C
Very low temperature change rate
Minimal power consumption/low operating costs
Quiet and vibration-free operation
Electrical safety circuits ensure safety (e.g., undertemperature protection)
Fully automatic operation
The fixed-point furnace was specifically designed to realize and display the melting plateau of the gallium cell (ITS-90 fixed point) to be able to.
The controller with timer function automatically controls the melting plateau.
Advantages of the Gallium Maintenance Furnace:
Gallium melting point available for 16 hours
Measurement uncertainty of 0.00025 °C at the melting plateau
Fully automatic operation
Easy handling
The maintenance furnace has a main bore for the mercury cell and two auxiliary bores for pre-cooling thermometers.
The cryostat temperature is adjustable from -36 °C to -42 °C.
Advantages of the Mercury Maintenance Furnace:
Safe melting and freezing of the mercury cell.
The mercury cell reaches operating temperature in only about one hour.
Cooling rate approximately 1 Kelvin/minute at operating temperature.
Heating rate approximately 2 Kelvin/minute at operating temperature.
Liquid-free
The entire temperature control is managed via the refrigerant flow. This guarantees trouble-free operation.
Advantages of Temperature Fixed-Point Cells
Precision: The high purity of 6N (99.9999%) enables long melting and freezing plateaus, where calibrations can be performed with very small measurement uncertainties.
Traceability: Calibrated temperature fixed points are traceable to international standards and internationally recognized.
Reproducibility: Thanks to their stability and reproducibility, temperature fixed points provide consistent results over long periods. This is crucial for repeatable measurements and ensuring quality standards in your operations.
Flexibility: The various temperature fixed points cover the broad temperature range of ITS-90. They are available as both large and slim temperature fixed points, making them versatile for use in both large tube furnaces and compact block calibrators.