Flextensional transducers

Abstract

A high power, low frequency flextensional transducer (50) for underwater use comprises a number of spaced piezo-electric element stacks (53) between opposed inserts (51, 52). A Kevlar (registered trademark) compression band (54) is wound around the stacks and inserts and then partly elliptical plaster formers (56) are attached. A filament wound elliptical GRP flexural shell (57) is then wound around the assembly while controlling the tension so as to provide the required pre-stress on the piezo-electric stacks (53) when cured. After curing the plaster formers (56) are removed. End-plates (16) are attached to the elliptical shell (57) to complete the transducer; the shell (11) having a compression bonded layer (61) of neoprene applied, including a peripheral serrated lip seal (62) to seal against the end-plate (16) while permitting flexing of the shell. A device to provide wide bandwidth performance is also disclosed. To extend the range of operational depths the cavity within the transducer is filled with a gas whose vapour pressure can be temperature-controlled.

Dependencies are inferred from the claim text.