Noise attenuating apparatus

• US 5,760,348 A
• Filed: 08/15/1996
• Issued: 06/02/1998
• Est. Priority Date: 04/28/1994
• Status: Expired due to Term

• Current Assignee: Tech.51, L.L.C.
• Original Assignee: Stephen Glen Heuser
• Inventors: Heuser, Stephen Glen
• Primary Examiner(s): Dang, Khanh
• Application Number:
  US08/689,840
• Time in Patent Office: 656 Days
• Field of Search: 181/229, 181/230, 181/232, 181/239, 181/238, 181/255, 181/267, 181/268, 181/269, 181/272, 181/282, 181/275
• US Class Current: 181/272
• CPC Class Codes: F01N 1/06 by using interference effect
• CPC Class Codes: F01N 1/08 by reducing exhaust energy by throttling or whirling
• CPC Class Codes: F01N 13/002 Apparatus adapted for particular uses, e.g. for portable devices driven by machines or engines
• CPC Class Codes: F01N 13/18 Construction facilitating manufacture, assembly, or disassembly
• CPC Class Codes: F01N 2490/16 Chambers with particular shapes, e.g. spherical
• CPC Class Codes: F01N 2590/06 for hand-held tools or portables devices

Abstract

Noise attenuator apparatus for use on a noise source including an exhaust inlet assembly using sound attenuators being equal to the exhaust pressure needs of the noise source whereby the sum total area of all smaller openings of the attenuators is equal to the exhaust volume needs of the noise source. Surrounding the inner or primary assembly, a sealed partition of any dimension containing an inner chamber which allows for the release of exhaust gas through any number of attenuators of which the smallest exit openings are equal to the exhaust volume needs of a noise source divided by the actual number of sound attenuators. The preceding assembly contained within this secondary chamber being contained or shrouded by an outer casing made from any number of plates or curved pieces whereby the primary and secondary chambers being contained by an outer casing through which the exhaust gas exits by way of measured openings or attenuators.

Claims

1. A noise attenuating apparatus comprising:

(a) a shroud;

(b) a first chamber formed in said shroud at least by a first chamber wall mounted within said shroud and having inlet means in communication therewith for receiving a fluid flow into said first chamber;

(c) a second chamber formed by said shroud and at least a portion of said first chamber wall of the first chamber, said noise attenuating apparatus having outlet means defining a passage in communication with said second chamber for communicating said second chamber with the ambient environment; and

(d) communicating means extending through said first chamber wall for providing communication between said first chamber and said second chamber for passage of the fluid flow from said inlet means to said second chamber, wherein said communicating means comprise a plurality of sound attenuators connected to said first chamber wall so as to project therefrom, wherein each said sound attenuator has a longitudinal passage therethrough that is defined by an interior surface and extends between a first orifice nearest said inlet means which receives the fluid flow from said inlet means and a second orifice farthest away from said inlet means from which the fluid flow passes into said second chamber, each said sound attenuator being tapered so as to narrow from said first orifice to said second orifice wherein the size of said first orifice in each said sound attenuator is greater than the size of said second orifice in each said sound attenuators said interior surface being substantially imperforate and elongate so that sound waves are reflected by said interior surface to effect destructive resistance of said sound waves during passage therethrough from said first chamber to said second chamber.

2. The noise attenuating apparatus of claim 1, wherein said shroud is defined by a plurality of flat sheets of a material which have cooperating U-shapes, said flat sheets being joined together to define at least said shroud of the noise attenuating apparatus.

3. A noise attenuating apparatus according to claim 1, wherein each said sound attenuator is conical shaped.

4. A noise attenuating apparatus according to claim 1 wherein the first chamber additionally has an outlet port defining a passage through said first chamber wall between said first and second chambers.

5. A noise attenuating apparatus according to claim 1, wherein said sound attenuators taper without flare.

6. A noise attenuating apparatus according to claim 1, wherein an end of said sound attenuator which defines said first orifice is mounted to said first chamber wall, said sound attenuator projecting in a downstream direction away from said first chamber wall.

7. A noise attenuating apparatus according to claim 1, wherein said passage of said outlet means comprises a plurality of spaced apart apertures formed in said shroud, said apertures being in communication with said second chamber and said ambient environment.

8. A noise attenuating apparatus comprising:

(a) a shroud;

(b) an innermost chamber formed in said shroud at least by a first chamber wall mounted within said shroud and having inlet means in communication therewith for receiving a fluid flow into said innermost chamber;

(c) at least one intermediate chamber formed within said shroud, at least a portion of said intermediate chamber being defined by said first chamber wall which is disposed between said intermediate chamber and said innermost chamber and a second chamber wall disposed within said shroud;

(d) an outermost chamber formed by said shroud and said second chamber wall which is disposed between said outermost chamber and said intermediate chamber;

said outermost chamber having outlet means in communication therewith for communicating said outermost chamber with the ambient environment;

(e) first communicating means for providing communication between said innermost chamber and said intermediate chamber for passage of the fluid flow from said inlet means to said intermediate chamber; and

(f) second communicating means for providing communication between said intermediate chamber and said outermost chamber for passage of the fluid flow from said intermediate chamber to said outermost chamber;

wherein said first and second communicating means each comprise one or more sound attenuators connected respectively to said first and second chamber walls wherein each said sound attenuator has a passage therethrough which extends between a first orifice closest to said inlet means and a corresponding second orifice farthest away from said inlet means, each said sound attenuator being tapered so as to narrow between said first orifice and said second orifice wherein the size of said first orifice is larger than the size of said second orifice so that noise generated by the fluid flow therethrough is attenuated, said first communicating means having said first orifice thereof in communication with said innermost chamber to receive the fluid flow from said inlet means and having said second orifice thereof in communication with said intermediate chamber, said second communicating means having said first orifice thereof in communication with said intermediate chamber and having said second orifice thereof in communication with said outermost chamber.

9. A noise attenuating apparatus according to claim 8, wherein the intermediate chamber consists of one chamber.

10. A noise attenuating apparatus according to claim 8, wherein each said sound attenuator is conical shaped.

11. A noise attenuating apparatus according to claim 8, wherein each of said first and second walls includes a plurality of said sound attenuators.

12. A noise attenuating apparatus according to claim 8, wherein each of said sound attenuators has an imperforate annular side wall which tapers from said first orifice to said second orifice to define said passage therethrough.

13. A noise attenuating apparatus comprising a chamber wall which defines an interior chamber therein and includes inlet and outlet means defining passages through said chamber wall respectively for a fluid flow into and out of said interior chamber, wherein said outlet means comprise a plurality of sound attenuators connected to said chamber wall wherein each said sound attenuator has a first orifice closest to said inlet means in communication with said interior chamber and a corresponding second orifice farthest away from said inlet means, each said sound attenuator having an annular side wall tapering without flare from said first orifice to said second orifice wherein the size of said first orifice closest to said inlet means is larger than the size of the second orifice farthest away from said inlet means, said annular side wall being elongate so that said side wall reflects sound waves during passage therethrough to effect destructive resistance of said sound waves, said sound attenuators protecting away from said chamber wall.

14. A noise attenuating chamber according to claim 13, wherein said outlet means include an outlet port defining a passage through said chamber wall for controlling a backpressure within said interior chamber from the fluid flow.

15. A noise attenuating apparatus comprising:

an enclosure which defines a hollow interior and includes an inlet for receiving a fluid flow into said hollow interior and an outlet for passage of said fluid flow out of said hollow interior; and

said hollow interior including a plurality of hollow expansion chambers wherein first and second ones of said chambers are in communication with said inlet and said outlet respectively, each one of said chambers being separated from an adjacent one of said chambers by a plate-like dividing wall therebetween which includes a plurality of elongate conical sound attenuators that project longitudinally away from said dividing wall, a fluid flow path being defined which extends from said inlet through said sound attenuators and to said outlet, each of said sound attenuators including a first orifice and a second orifice which is smaller than said first orifice wherein said fluid flow path passes through said sound attenuator and exits through said second orifice thereof, each of said sound attenuators further including an annular side wall which has an interior surface that tapers without flare so as to narrow in a downstream direction extending away from said first orifice, said side wall being substantially imperforate between said first and second orifices such that reflected sound waves are reflected by said interior surface to generate a destructive resistance pattern of sound waves and attenuate noise generated by a fluid flow during passage through said sound attenuator, each of said first and second orifices being smaller than said inlet opening and said outlet opening.

16. A noise attenuating apparatus according to claim 15, wherein at least a third chamber is defined between said first and second chambers, said first to third chambers being in communication with each other by said sound attenuators.