Pvdf ultrasonic sensor (for application in gasses

This dissertation surveys theoretical and experimental work on Polyvinylidene Fluoride (PVDF) piezoelectric with special emphasis on its the ultrasonic sensor transducing element on investigation a polymer application in in the form of providing the domestic gas flow meter. For studies performed, the commercial polarized PVDF film based on 25 um and 40 µm thick were purchased from Yarsley Technical Centre ltd. These were the thickness of product available at that time.

The preliminary theory involving the propagation of ultrasonic wave in gases and piezoelectric A transducer are briefly reviewed. number of modification of the probe design involving a flat, focus and multilayers structures with a backing material, e.g. polystyrene, perspex and polyurethane foam were investigated. Method of construction, signal amplification and rf shielding are discussed, and data are presented on the sensitivity and frequency response of the sensors.