Improvements in or relating to subaqueous sound receivers and transmitters

Abstract

Abstract 352,040. Subaqueous sound signals; plate vibrators ; mounting piezo-electric units. SOC. DE CONDENSATION ET D'APPLICATION MECANIQUES, 42, Rue de Clichy, Paris, and TOULY, M., 9, Chaussee du Pont, Boulogne-sur-Seine, both in France. Jan. 28, 1930, No. 2948. Convention date,. Feb. 25, 1929. [Classes 13 and 118 (ii).] A metal plate is interposed between a subaqueous sound transmitter or receiver and the sea, the thickness of the plate or of the combined plate and transmitter being K#/2, where # is the wavelength of an oscillation in the plate and K is any integer, the plate being secured along one of its nodal lines or in a position corresponding to a nodal line of the combined plate and transmitter. The distance, Fig. 1, of a nodal line from the outer face of the plate is stated to be given by the formula- #/4 + K1#/2, where K<1> is any integer or is zero. The invention is shown in Fig. 2 as applied to a piezoelectric transmitter-receiver. The piezo unit 6 is placed in a holder 1 screwed into a flange 3 attached to the skin 5 of the ship. The holder 1 also carries the plate 2 dimensioned according to the present invention, acoustic contact between the unit and the plate being provided by a layer 8 of mercury or other liquid. In a modification, the combined thickness of the unit and the plate is #/2 and the distance from the surface of the plate to its point of attachment is #/4.

Inventors

No inventors recorded.

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