Hitco, Inc.

Donald M Hatch

George D Lee

Richard J Larsen

A carbon-organic resin composite which has been initially shaped as by molding and in which the resin binder has been at least partially precured is transformed into an all-carbon composite and substantially densified by a continuous process in which the composite is continuously heated at different temperatures and subjected to increased pressure. Initially, the composite is heated at a first rate to a temperature on the order of 1000.degree. F., the first rate and the increased pressure applied to the composite being selected to substantially decompose the resin rapidly but without delamination or other damage to the composite. Heating is then continued at a second rate until the composite undergoes substantial softening and becomes plastic, typically at a temperature in excess of 3500.degree. F. Thereafter the composite is maintained at a high temperature, typically in excess of 5000.degree. F., for a selected period of time while at the same time continuing the application of high pressure to provide substantial densification of the composite. The continuous process is carried out in 6-12 hours for composites within a given size range.

High temperature consolidation process

High temperature consolidation process for the production of a

An underwater panel comprises a three-dimensional structure for housing sound absorbing material therein, the structure being waterproof and extremely rigid in construction to prevent compression of the sound absorbing material in an environment of relatively high water pressure while at the same time being relatively highly sound transmissive so as to readily pass energy waves from the surrounding water into the sound absorbing material. The panel comprises an integrally woven and resin impregnated fabric which is relatively highly sound transmissive and which has a pair of waterproof opposite faces joined by a pair of intermediate ribs. A plurality of generally planar stiffening elements which are highly sound transmissive and which may be made from resin impregnated fabrics are inserted into the fabric so as to extend between the opposite faces and provide substantial resistance to compression of the panel due to the pressure of the surrounding water. These stiffening elements which are either disposed adjacent single ribs or within pockets formed by parallel pairs of ribs combine with the ribs to define spaces between the opposite faces in which highly sound absorbent material resides.

Structural sound absorbing panel for underwater use and methods of

Acoustical panels are comprised of woven fabrics which have at least one face ply portion woven of warp and fill yarns comprising yarns of non-fugitive and fugitive material. The fabric is woven relatively densely to facilitate handling and use thereof in fabrication of the acoustical panel. The substantial disintegration of the fugitive strands of yarn at the completion of the fabrication process provides a selected porosity in the face portion of the woven fabric for controlled transmission of sound waves into the interior of the panel. In a preferred method of making an acoustical panel, the fabric is woven of yarns comprising a mixture of non-fugitive and fugitive material. After installation of porous acoustical elements into pockets formed in the face portion and insertion of mandrels into flutes formed within the fabric, the fabric is impregnated with resin, cured, and the mandrels removed. The formed panel is then heated to a temperature sufficient to burn out the fugitive yarns without affecting the non-fugitive yarns to provide the face portion with a desired porosity to sound waves.

Method of making woven acoustical panel

A multi-ply woven article has elements positioned within pockets formed by double plies of the article to provide the article with desirable acoustical properties as well as considerable strength and rigidity. The double plies may comprise a generally parallel pair of rib plies which extend between the opposite faces of the article in generally zig zag fashion to form a plurality of intermediate rib portions, or a pair of generally parallel, spaced apart face plies forming each of the opposite faces of the article, or both. Some of the pockets formed by the double plies are filled with acoustical elements having a selected number of holes of appropriate size so as to pass sound waves therethrough at a controlled rate, while still other pockets are filled with non-acoustical elements which are generally impervious to sound waves. By appropriate location of the acoustical and non-acoustical elements the article is effectively provided with a plurality of chambers which trap and dissipate sound wave energy entering from outside the article.

Multi-ply woven article having acoustical elements between double plies

A multi-ply woven article has stiffening elements positioned within pockets formed by double plies of the article to provide the article with substantial strength and rigidity. The double plies may comprise a generally parallel pair of rib plies which extend between the opposite faces of the article in generally zig zag fashion to form a plurality of intermediate rib portions, or a pair of generally parallel, spaced apart face plies forming each of the opposite faces of the article, or both. The various stiffening elements may comprise one or more layers of relatively stiff material. The various layers comprising each stiffening element may comprise unidirectional fibers or materials oriented relative to the woven article so as to impart maximum strength in selected directions. In a preferred method of making woven articles in accordance with the invention the multi-ply fabric is woven and the individual stiffening elements are made, after which the woven fabric is resin impregnated, the pockets thereof filled with the stiffening elements and open spaces in the fabric filled with mandrels. Thereafter the fabric is cured and the mandrels subsequently removed to form the finished article.

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Huntington Beach, CA, United States of America

Donald M Hatch