Accession Number : ADD002401

Title :   Acoustic Baffle for Deep Submergence.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON D C

Personal Author(s) : Johansen,Carl R

Report Date : 02 Dec 1975

Pagination or Media Count : 5

Abstract : This invention relates to a multi-layered acoustic baffle, particularly useful at great depths underwater, comprising at least two layers of fumeproduced silicon dioxide, the particle size being between 70 to 500 angstroms, the particles being sintered together in chain-like formations and having surface areas of 50 square meters/g to 400 square meters/g. Each of the layers is prestressed to a pressure greater than the pressure at which the baffle is to be used, and each of the layers has a thickness not greater than 1/4 wavelength of the highest frequency of interest in the material. At least one layer of high-density, viscoelastic, material, having a high acoustic loss coefficient shear, is sandwiched in between each layer of the silicon dioxide. Two layers of a compliant watertight coating bordering the two outer layers of silicon dioxide and the sides of the baffle completely enclose the layers.

Descriptors :   *Underwater equipment, *Baffles, *Patents, Deep submergence, Acoustic absorption, Silicon dioxide, Waterproofing

Subject Categories : Marine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE