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A liquid-filled acoustic transducer for finishing an exposed surface of a work medium, such as plastic concrete, transmits acoustic energy generated within an enclosed liquid medium, through a transducer housing member, and into the exterior work medium. Acoustic waves are generated by electrically-

A liquid-filled acoustic transducer for finishing an exposed surface of a work medium, such as plastic concrete, transmits acoustic energy generated within an enclosed liquid medium, through a transducer housing member, and into the exterior work medium. Acoustic waves are generated by electrically-actuated liquid-immersed piezoelectric elements housed within the device. The efficiency with which acoustic waves are transmitted from the interior of the device to the adjacent work medium is enhanced by providing an intermediate transducer housing member, disposed between the liquid in which the piezoelectric elements are immersed and the work medium, having acoustic impedances at its two major surfaces matching the respective acoustic impedances of the respective interfacing media and a continuous acoustic impedance gradient between those two surfaces.

대표청구항 ▼

[ What is claimed is:] [1.] An acoustic transducer, comprising: ransducer housing surrounding a transducer housing interior;said transducer housing comprising a top portion and a bottom portion removably attached to said top portion;said bottom portion having a thickness measurable between an interi

[ What is claimed is:] [1.] An acoustic transducer, comprising: ransducer housing surrounding a transducer housing interior;said transducer housing comprising a top portion and a bottom portion removably attached to said top portion;said bottom portion having a thickness measurable between an interior surface and an exterior surface;said exterior surface being adapted to engage a work medium;said interior surface having a first acoustic impedance;said exterior surface having a second acoustic impedance;said top portion having a third acoustic impedance different from said first acoustic impedance; iquid disposed within said transducer housing interior;wherein said liquid has an acoustic impedance;a value of said acoustic impedance of said liquid substantially matching said first acoustic impedance of said interior surface; iezoelectric member immersed in said liquid; and, energizing means for electrically energizing said piezoelectric member;said energizing means comprising means for applying an alternating voltage to said piezoelectric member at a first frequency.