The gas tiny flow measurement instrumentation

摘要

The paper presents the design and experimental experience with the gas flow measurement instrument for the range of (5-25) ml/hr. The aimed application area is in a biochemical laboratory for the study of reaction kinetic of sediments decomposition in waste water. The time-of-flight type of sensor with one upstream and one downstream temperature sensor has been chosen for the study. We explain the basic operation principles of the tiny flow measurement and the sensor structure. In the numerical model paragraph, we are describing the basic configuration model and the modelling results. As the three-dimensional simulation would be very time consuming process, we have simplified the simulation for only two-dimensional task. The presented diagrams are derived for different gases (air, nitrogen, carbon oxide and chlorine) and sensor tube materials, namely steel, copper, and plexi-glass. We present also the experimental set-up including the design and sensor parameters. The paragraph with experimental results and discussion on them illustrates the good correspondence with expected values. The paper concludes with the employment of designed gas flowmeter in the biochemical laboratory. © ECMS Valeri M. Mladenov, Petia Georgieva, Grisha Spasov, Galidiya Petrova (Editors).