Highly sensitive & accurate gas properties sensing with SCL’s self-sensing cantilevers

Measurement and evaluation of gas density and viscosity of pure gases and mixtures

In this application Mr. Badarlis (Aristotle University of Thessaloniki) and his colleagues developed a gas cell setup for measurement of gas density and viscosity by using a SCL micro-cantilever beam (PRSA-L300-F50). In parallel, the validity of a proposed modelling approach was evaluated.

The density and viscosity of gases are orders of magnitude lower than liquids. For this reason, the use of a very sensitive sensor is essential. Although the used cantilever was designed to work with thermal activation, it was activated with an electromagnetic force. Therefore, the heater structure on the cantilever was driven with an alternating current and the cantilever itself was placed in front of a permanent magnet. The deflection of the cantilever beam was detected by an integrated piezo-resistive sensor on the cantilever.

Six pure gases and sixteen mixtures of them in ambient conditions were investigated. The outcome of the investigation showed that the current cantilever beam had a sensitivity of 240 Hz/(kg/m3), while the accuracy of the determined gas density and viscosity in ambient conditions reached ±1.5% and ±2.0%, respectively.

 

Photo of the gas cell developed by Mr. Badarlis. The micro-cantilever beam and its silicon chip are mounted on a small 5x6mm PCB. In addition, the magnet as well as a pressure, a temperature and a humidity sensors are shown.

Schematic diagram of the experimental gas measuring setup based on a micro-cantilever.

Frequency spectrum for different gases.

 

Reference:

Anastasios Badarlis et al.: Measurement and Evaluation of the Gas Density and Viscosity of Pure Gases and Mixtures Using a Micro-Cantilever Beam. Sensors 2015, 15(9), 24318-24342; published: 2015 Sept. 22, doi:10.3390/s150924318.

Paper Link(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4610587/)