US2942681A - Noise reduction device for submarines - Google Patents

Noise reduction device for submarines Download PDF

Info

Publication number
US2942681A
US2942681A US681147A US68114757A US2942681A US 2942681 A US2942681 A US 2942681A US 681147 A US681147 A US 681147A US 68114757 A US68114757 A US 68114757A US 2942681 A US2942681 A US 2942681A
Authority
US
United States
Prior art keywords
rings
noise
bars
sound
hull
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US681147A
Inventor
Morris W Lindman
Original Assignee
Morris W Lindman
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Morris W Lindman filed Critical Morris W Lindman
Priority to US681147A priority Critical patent/US2942681A/en
Application granted granted Critical
Publication of US2942681A publication Critical patent/US2942681A/en
Anticipated expiration legal-status Critical
Application status is Expired - Lifetime legal-status Critical

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B63SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63GOFFENSIVE OR DEFENSIVE ARRANGEMENTS ON VESSELS; MINE-LAYING; MINE-SWEEPING; SUBMARINES; AIRCRAFT CARRIERS
    • B63G8/00Underwater vessels, e.g. submarines; Equipment specially adapted therefor
    • B63G8/04Superstructure

Description

June 28, 1960 M. w. LINDMAN uoxsa REDUCTION .DEVICEFOR SUBMARINES Filed Aug. 29, 1957 3%?! was 395 INVENTOR v v1ZW'f/J Aka mew,

.BY /'6 A.

ATTORNEYS United States Patent 2,942,681 NOISE REDUCTION DEVICE FOR Morris w. Lindman, Adelphi, Md, assignor m the United States of America as represented by the Secretary of the Navy Filed Aug. 29, 1957, Ser. No. 681,147

7 Claims. (Cl. 181-33) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to sound absorbing systems and particularly to systems for absorbing structure-borne noise.

More particularly, this invention relates to the reduction of noise transmission from submarines, minesweepers and other vessels to ambient waters.

With submarines, for example, inherently noisy machinery hereinafter referred to as noise-producing machinery, is mounted on resilient mountings which in turn are supported on the structural rings that reinforce the pressure hull of the ship. With present submarines, a large part of the structure-borne noise of the machinery is transmitted through the mounting and hence to the reinforcing rings, the pressure hull, and to ambient waters. This transmission of noise to surrounding water is extremely dangerous in that the presence of the submarine may readily be detected from the noise by known detecting devices.

Therefore, a broad object of the present invention is to reduce the transmission of structure-borne noise to ambient media.

Another object of this invention is to absorb structureborne noise.

A further object of this invention is to provide a path of highly efficient acoustical power transmission for the transmission of absorbed noise from a source to a place of absorption.

A more specific object of this invention is to provide a plurality of structural sound-transmitting paths of highly efiicient acoustical power transmission from inherently noisy machinery, and of converging such paths in a sound absorbing material.

Briefly, in applying the instant invention to the hull of a submarine, for example, a plurality of metal, noisetransmitting rings, one for each of the structural reinforcing rings, is mounted between the reinforcing rings and the interior of the pressure hull. The noise-transmitting rings are interconnected by a plurality of spaced metal bars, all of which bars converge into a single bar or rod within and spaced from the stern of the ship. The single bar is embedded within a substantial volume of sound absorbing material and is equipped with a plurality of spaced disks of various natural frequencies, which disks are loosely embedded within the sound absorbing material.

The plurality of sound-transmitting rings and the plurality of bars make up a squirrel-cage, the material of which is of higher specific acoustic impedance than that of the rest of the ships structure, thereby forming a path, or rather a plurality of paths of least resistance that converge into a single path, which single path is surrounded by a relatively thick bedding of sound absorbing material. In other words, the sound-transmitting rings 2,942,681 Patented June 28, 1960 and bars that make up the squirrel cage should be of a material such that its impedance matches the output impedance of the driver better than the impedance of the hull or casing, thereby forming a plurality of paths of highly efiicient acoustical power transmission for transmitting noise from the machinery to a concentration region remote from the machinery; a structure which conducts more vibrational energy away from the machinery than does the hull or casing. The sound-transmitting rings are insulated from the metal of the pressure hull and the bars are preferably coated with a highly dissipative material, such as a suitable plastic, to minimize their vibration between the rings and radiation to the hull.

Thus, there is provided a plurality of paths for transmitting structure-borne noise from inherently noisy machinery to a concentration area wherein the noise is smothered and suppressed in a substantial volume of sound absorbing material. As used herein, noise is intended to refer to structure-borne noise" and is not intended to include noise that is transmitted or radiated through air. The squirrel-cage of the instant invention is not intended to be, and preferably is not, a strength member for the ship.

The invention, together with the above and other obljects and advantages, is set forth in more technical detail in the following description and accompanying drawing wherein the single figure is a schematic perspective view, partly in section, of the stern or aft portion of a submarine, illustrating a preferred embodiment of the invention.

Referring now to the drawing, reference numeral 10 designates the pressure hull of a submarine, to the interior of which is securely mounted a plurality of reinforcing rings 12, only two of which rings are shown in the drawing. As is customary, various noise-producing machinery (not shown) is mounted on the reinforcing rings.

In accordance with this invention, a plurality of metal, noise-transmitting rings 14, one for each of the reinforcing rings, are mounted between the reinforcing rings and the interior surface of the pressure hull. The rings 14 are in metal-to-metal contact with the reiifiorcing rings, but are insulated by suitable means, not shown, from the pressure hull. A plurality of metal bars or straps 16 are attached to the rings 14 and converge in a region A, from which extends a single metal bar or rod 18, on which rod is located a plurality of disks 20 of various natural frequencies. The region of convergence, A, of bars 16, the rod 18 and the disks 20 are located within and spaced from the stern of the ship, which space is filled with sound absorbing material, 21, which may be a mineral wool, or glass fiber batting or the like. The sound absorbing material is confined within the stern by a partition or bulkhead 22, which partition is provided with a plurality of openings 24 for passage of the bars 16 therethrough and out of contact with the partition.

The sound-transmitting rings 14 and bars 16 that make up the squirrel-cage, and the rod 20 are each formed of the same material, a material having a higher specific acoustic impedance than that of the rest of the ships structure. The material of the squirrel cage is such that its impedance matches the output impedance of the driver (machinery) better than the impedance of the hull or casing, thereby forming a structure which conducts more vibrational energy away from the machinery than does the hull or casing. For steel ships, this material may be nickel or steel with a high nickel content. In wooden ships, such as mine sweepers, almost any non-magnetic metal may be used. So as to minimize vibration of the bars or separate elongated, rodlike metal sound conducting members 16 between the rings 14, the bars are coated with a highly dissipative plastic material, such as polyethylene or polystyrene, the latter being preferred because I of its ability to withstand somewhat higher temperature without distortion.

-Thus it is seen, in accordance with the illustrated embodiment of the invention, structure-borne noise is transmitted from inherently noisy machinery, mounted on or supported by the reinforcing rings, by the members of the squirrel-cage, to a region within the stern of the ship, wherein the noise is smothered in the sound absorbing material.

The invention is herein illustrated as applied to noiseproducing machinery of a submarine or the like. The invention may, however, be applied with equal facility to other noise-producing machinery. It should therefore be understood that the foregoing disclosure relates to only a preferred embodiment of the invention and that numerous modifications or alterations may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

1. A submarine or the like comprising a metallic hull, a skeleton machinery supporting frame on the interior of said hull, sound insulating means between said frame and said hull, and sound attenuating means adjacent a terminal portion of said hull and acoustically insulated therefrom, said frame being operatively connected to said attenuating means.

2. The combination of claim 1 in which the sound attenuating means comprises a plurality of laterally spaced metal bars, each of which conducts more vibrational 4 energy away from said machinery supporting frame than does said hull.

3. The combination of claim 1 in which the sound attenuating means comprises a network of sound conducting bars and rings, and sound absorbing material encompasses the bars and rings.

4. The combination of claim 1, including a. network formed of sound conducting bars and rings, and sound absorbing material encompassing the bars and rings.

5. The combination of claim 1, which includes a central rod, a plurality of sound dissipating disks mounted in spaced relation on said rod and embedded within the sound absorbing material.

6. The combination of claim 1, which includes inherently noisy machinery disposed within said hull, a network formed of sound conducting bars and rings, and sound absorbing material encompassing said bars and rings.

7. The combination of claim 6 in which the sound absorbing material is mineral wool batting.

References Cited in the file of this patent UNITED STATES PATENTS Stewart et al Jan. 17, 1956

US681147A 1957-08-29 1957-08-29 Noise reduction device for submarines Expired - Lifetime US2942681A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US681147A US2942681A (en) 1957-08-29 1957-08-29 Noise reduction device for submarines

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US681147A US2942681A (en) 1957-08-29 1957-08-29 Noise reduction device for submarines

Publications (1)

Publication Number Publication Date
US2942681A true US2942681A (en) 1960-06-28

Family

ID=24734041

Family Applications (1)

Application Number Title Priority Date Filing Date
US681147A Expired - Lifetime US2942681A (en) 1957-08-29 1957-08-29 Noise reduction device for submarines

Country Status (1)

Country Link
US (1) US2942681A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3170435A (en) * 1962-05-01 1965-02-23 Outboard Marine Corp Engine soundproofing

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US989958A (en) * 1909-10-30 1911-04-18 Hermann Frahm Device for damping vibrations of bodies.
US1416950A (en) * 1918-08-26 1922-05-23 Submarine Signal Co Ship protection
US1658349A (en) * 1926-03-26 1928-02-07 Western Electric Co Loud-speaking receiver
US1678116A (en) * 1923-10-16 1928-07-24 Western Electric Co Device for the transmission of mechanical vibratory energy
US1972005A (en) * 1931-07-21 1934-08-28 Berbeck Trian Aircraft
US2731606A (en) * 1951-07-26 1956-01-17 Gen Electric Structure for reduction of audible sound

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US989958A (en) * 1909-10-30 1911-04-18 Hermann Frahm Device for damping vibrations of bodies.
US1416950A (en) * 1918-08-26 1922-05-23 Submarine Signal Co Ship protection
US1678116A (en) * 1923-10-16 1928-07-24 Western Electric Co Device for the transmission of mechanical vibratory energy
US1658349A (en) * 1926-03-26 1928-02-07 Western Electric Co Loud-speaking receiver
US1972005A (en) * 1931-07-21 1934-08-28 Berbeck Trian Aircraft
US2731606A (en) * 1951-07-26 1956-01-17 Gen Electric Structure for reduction of audible sound

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3170435A (en) * 1962-05-01 1965-02-23 Outboard Marine Corp Engine soundproofing

Similar Documents

Publication Publication Date Title
US3540547A (en) Acoustical systems for air moving devices
US4160229A (en) Concentric tube hydrophone streamer
CA1296649C (en) Active acoustic attenuation system for higher order mode non-uniform sound field in a duct
US3276539A (en) Sound isolating enclosure for internal combustion engine generator set
US4584232A (en) Foam material sound absorption
FR1321822A (en) membrane tanks
Warnaka Active attenuation of noise-the state of the art
US4809243A (en) Streamer cable
Fahy Foundations of engineering acoustics
Gardonio et al. Active control of structure-borne and airborne sound transmission through double panel
US20070006723A1 (en) Acoustic shock wave attenuating assembly
US2448352A (en) Piezoelectric crystal mounting means
GB1086776A (en) Transducer
Tokhi et al. Active sound and vibration control: theory and applications
Snyder et al. Mechanisms of active noise control by vibration sources
US4759000A (en) Acoustic energy absorbing material
US4955012A (en) Seismic streamer cable
US5394786A (en) Acoustic/shock wave attenuating assembly
FI79499C (en) Elastic mounted in propelleranordning.
US3271596A (en) Electromechanical transducers
US1380869A (en) Submarine signaling
JPH02212795A (en) Fluid level monitor
US5225622A (en) Acoustic/shock wave attenuating assembly
US20110139542A1 (en) Acoustic shield
GB1369345A (en) Sound absorption structure