THICK-FILM THERMALLY EXCITED RESONATOR FOR MASS FLOW MEASUREMENT

D. Crescini, D. Marioli, A. Taroni

Abstract

This paper illustrates the design and the development of a thick-film mass flow sensor based on the frequency shift of a resonating ceramic structure. The mechanical oscillator realized uses a measurement principle of thermoanemometric type. The sensor can measure mass flows up to 15 × 10⁴ sccm (sccm: 10 sccm = 0.17 mg/s), with high sensitivity. Here we report on the first prototype consisting of a beam 0.254 mm thick , 4 mm large and 17 mm long, in which the temperature variations induced by flow, affect the resonance frequency. Predicted and measured values for the shift of the resonance frequency agree well. At the first flexural mode of vibration of 3.5 kHz and at an average temperature rise of the substrate of 100 ° C, a frequency change of 500 Hz in the mass flow range from zero to 15 × 10⁴ sccm can be measured. Indications are proposed for reducing the time response and increasing the sensitivity.

Keywords

thick-film sensors, mass flow measurement, PZT resonators

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IMEKO-WC-2000-TC9-P235.pdf

DOI

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IMEKO TC

TC9 - Flow Measurement

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