Author :
Anisimkin, V.I. ; Penza, M. ; Maksimov, S.A. ; Vasanelli, L.
Abstract :
Uncoated SAW delay lines performing as thermal probes are applied for detection of gases and gas flows. Analysis of the forced convection is performed for 13 analytes in linear approximation by neglecting their chemical interaction with the ambient. Experimental detection is performed for H2, He, Ar, CH4, NH3, N 2, O2, dry air, using SAW delay lines on SiO2 , LiNbO3, Bi12GeO20, Bi12 SiO20, at operating temperatures T=25-165°C and frequencies f=21-263 MHz. SAW responses are measured as a function of concentration n, flow rate u, temperature coefficient of velocity (TCV) and temperature T. Efficient selectivity and monitoring of the responses are demonstrated by a proper selection of TCV and T. Detection of 0.35% CH4, 0.25% H2 and 0.1% NH3 in N2 is performed. Linear output for u=50-2000 ml/min is obtained
Keywords :
flow measurement; forced convection; gas sensors; probes; surface acoustic wave delay lines; surface acoustic wave sensors; temperature measurement; 21 to 263 MHz; 25 to 165 C; Ar; Bi12GeO20; Bi12SiO20; CH4; H2; He; LiNbO3; N2; NH3; O2; SAW delay lines; SAW responses; SiO2; dry air; flow rate; forced convection; gas concentration; gas detection; gas flows; linear approximation; temperature coefficient of velocity; thermal detection; thermal probes; uncoated delay lines; Bismuth; Chemical analysis; Delay lines; Fluid flow; Gases; Linear approximation; Performance analysis; Probes; Surface acoustic waves; Temperature;
