Use of a surface-acoustic-wave (SAW) device to measure gas flow

The use of a surface-acoustic-wave (SAW) device to measure the rate of gas flow is described. The device is a delay-line stabilized SAW oscillator heated to a suitable temperature above the ambient. Flow of gas carries heat away by convection. This lowers the substrate temperature, thereby causing change in oscillator frequency. The frequency of a 68-MHz oscillator fabricated on Y-Z LiNbO/sub 3/ substrate increases by more than 160 kHz for variation in flow rate from 0 to 1000 cm/sup 3//min.<
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