GB1465932A - Sound reflective elements - Google Patents

Abstract

1465932 Sound reflectors; subaqueous transducers FRANCE ARMED FORCES MINISTER OF 31 July 1974 [16 Aug 1973] 33890/74 Headings H4X and H4J A sound reflector for underwater use comprises a fluid-tight, elastically deformable envelope containing a lattice of crossed filaments disposed between two substantially rigid panels. The lattice has punctiform points of contact and is preferably formed of wires. It is preferably formed of plaited or braided wires. Several superimposed layers (e.g. 3 or 5) may be used. The crossed wires may be connected together at the intersection points by ties or binders or by spot soldering but this reduces the reflecting power at high pressures. Several layers of wire lattices 2a, 2b, 2c (Fig. 1) are sandwiched between metal sheets 3a, 3b approximately 1 mm. thick or sheets of laminated synthetic resin, e.g. polyester laminate. An envelope 4 is of natural or synthetic resin. The lattice may be of steel wires of diameter 0À5 to 2À00 mm., the meshes being from 0À5 mm. to 5 cm. An acoustic antenna (Fig. 2) is composed of transmitter or receiver electro-acoustic transducers mounted on a rigid support 7. A flat reflective surface 8 is formed of identical juxtaposed sound reflectors 8a disposed between the various transducers 6 and the support. Each sound reflector 8a is composed of a fluidtight envelope containing one or more layers of crossed wire lattices disposed between two rigid plates. The surface 8 may be cylindrical, polygonal or spherical. The reflectors 8a may be flat or curved.