The new ThermoHybrid by Rüeger SA

13 December 2017

High-Accuracy Process Temperature Sensor

Rüeger SA is introducing its new ThermoHybrid, a high-precision temperature sensor for process applications. This modern version of a constant-volume gas thermometer uses a high-precision pressure gauge to measure the pressure in a cartridge filled with noble gas, to which it is connected via a stainless steel capillary. This combination yields an accuracy which is significantly better than the accuracy of thermocouples, and even better than the accuracy of most Pt100’s.

The measurement range may cover any range between -260°C and +750°C (with special ranges up to 1050°C) and is easily adapted to the customer needs by adjusting the initial filling pressure. The size of the gas cartridge and the length of the capillary are both customized to the customer application.

In the high-temperature range around 750°C, the ThermoHybrid achieves an accuracy of +/- 1°C at a temperature of 750°C which makes it about four times more accurate than a thermocouple. For a measurement range of up to 150°C, accuracy increases to +/- 0.1°C which puts it into competition with a Pt100 class 1/10 DIN. Moreover, the ThermoHybrid does not show any drift over time.

The ThermoHybrid is the ideal device for a measurement of average temperatures (over a cross section or along a defined length), as the indicated temperature always corresponds to the average temperature of the gas cartridge. The length of the gas cartridge can easily be adapted to the application and may range from several cm to several meters.

For critical applications in terms of safety (SIL), the ThermoHybrid provides an alternative measurement principle to PT100 or thermocouple, without having to compromise accuracy.

Temperature readings are transmitted via a 4-20 mA interface and CAN-Bus. Sensor heads are standardized industrial versions or customized designs.