Bulk acoustic absorber panels for use in high speed gas flow environments

• US 4,313,524 A
• Filed: 12/17/1980
• Issued: 02/02/1982
• Est. Priority Date: 12/17/1980
• Status: Expired due to Fees

• Current Assignee: Rohr Industries, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Rohr Industries, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Rose, Philip M.
• Primary Examiner(s): Hix, L. T.
• Assistant Examiner(s): Fuller, Benjamin R.
• Application Number:
  US06/217,209
• Time in Patent Office: 412 Days
• Field of Search: 181/213, 181/214, 181/222, 181/224, 181/286, 181/290, 181/291-293, 55/276, 428/116-118
• US Class Current: 181/291
• CPC Class Codes: B32B 2250/40 Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
• CPC Class Codes: B32B 2262/101 Glass fibres
• CPC Class Codes: B32B 2266/06 Open cell foam
• CPC Class Codes: B32B 2307/10 having particular acoustical properties
• CPC Class Codes: B32B 2605/18 Aircraft blades, propellers B32B2603/00
• CPC Class Codes: B32B 3/26 characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids foam layer B32B5/18; layer of synthetic resin characterised by fillers that create voids or cavities B32B27/205; characterised by an apertured layer
• CPC Class Codes: B32B 3/266 characterised by an apertured layer, the apertures going through the whole thickness of the layer, e.g. expanded metal, perforated layer, slit layer regular cells B32B3/12
• CPC Class Codes: B32B 5/18 characterised by features of a layer of foamed material
• CPC Class Codes: E04B 1/84 Sound-absorbing elements
• CPC Class Codes: E04B 2001/8428 containing specially shaped acoustical bodies, e.g. funnels, egg-crates, fanfolds
• CPC Class Codes: E04B 2001/8442 Tray type elements
• CPC Class Codes: E04B 2001/8452 with peripheral frame members
• CPC Class Codes: F02C 7/24 Heat or noise insulation air intakes having provisions for noise suppression F02C7/045; turbine exhaust heads, chambers, or the like F01D25/30; silencing nozzles of jet-propulsion plants F02K1/00

Abstract

A sandwich type acoustical absorbing panel for use adjacent high speed gas flow areas in and around the engines of high speed aircraft. The panel comprises a pan type base having an imperforate base member and upstanding sides and end walls, an acoustic absorbing medium is disposed within the pan type base, a rigid perforated plate is secured to the distal surfaces of the upstanding sides and end walls for enclosing the acoustic absorbing medium and a sheet of fine woven mesh is secured to the outer surface of the rigid perforated plate. The outer positioned fine woven mesh enhances acoustic properties of the panel and substantially prevents entry of water, dust, chemicals and similar foreign matter from penetrating into the panel structure and reduces the aerodynamic drag loss normally encountered by high speed gas flows across perforated material, such as, that normally used for the outer surface of acoustic panels.

Claims

1. A structurally efficient acoustic absorber panels comprising:

a rigid open base member which comprises a back plate, end and side walls;

acoustic absorber means disposed within the opening of said rigid base member;

a rigid perforated plate is attached to said end and side walls for forming a cover for said opening of said rigid base member for enclosing said acoustic absorber means, the perforations of said perforated sheet are sufficient in number and cross-section to provide a large actual open area therethrough; and

a layer of fine woven wire cloth material is adhered by adhesive means to the outer surface of said perforated sheet, the pores through said sheet of said wire cloth material provide a pre-determined flow through resistance through the combined perforated sheet and layer of wire cloth material,

whereby a high speed gas flow across said layer of fine woven wire cloth material encounters a minimum of surface resistance, and provides a high degree of sound absorbtion while substantially impervious to water, dust, chemical and various other contaminants.

2. The invention as defined in claim 1, wherein said acoustic absorber means is open celled plastic foam.

3. The invention as defined in claim 1, wherein said acoustic absorber means is batts of fiberglass material.

4. The invention as defined in claim 1, wherein said acoustic absorber means is felt material.

5. The invention as defined in claim 4, wherein said felt material is constructed of Kevlar®

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