ACOUSTIC COAT Russian patent published in 2001 - IPC

FIELD: underwater acoustics. SUBSTANCE: invention is related to aid used in measurement technology to control noise. It can be employed to equip underwater acoustic basins and deep-sea stands and can be installed on hull structures of underwater transportation craft, ships and vessels. Proposed acoustic coat is manufactured in the form of pressed plate of rubber-like material. It is composed of outer sealing layer, sound-absorbing layer with air spaces linked to it and sound- reflecting layer. Air spaces of sound-absorbing layer come in the form of truncated cones which cross-section grows as much as 5 times as minimum in direction opposite to sealing layer and entire area of bases of cones amounts to 0.2-0.6 of total area of layer. Sound-reflecting layer has cylindrical air spaces whose height amounts to 0.2- 1.5 height of cone of sound-absorbing layer. Layers can be laid with displacement of holes in them and outer edges of holes in sound-reflecting layer can be flared in accord with one version. In this case outer side of this layer can be covered by layer of rubber-like material to enhance efficiency of sound absorption. EFFECT: increased level of absorption of sound energy by coat, diminished sound reflection from it in wide range of frequencies. 3 cl, 5 dwg