GB2172966A - Reduction of noise emission - Google Patents

Reduction of noise emission Download PDF

Info

Publication number
GB2172966A
GB2172966A GB08507935A GB8507935A GB2172966A GB 2172966 A GB2172966 A GB 2172966A GB 08507935 A GB08507935 A GB 08507935A GB 8507935 A GB8507935 A GB 8507935A GB 2172966 A GB2172966 A GB 2172966A
Authority
GB
United Kingdom
Prior art keywords
shield
evacuated
engine
noise
space
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.)
Withdrawn
Application number
GB08507935A
Other versions
GB8507935D0 (en
Inventor
Eric John Hoile
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ford Motor Co
Original Assignee
Ford Motor Co
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 Ford Motor Co filed Critical Ford Motor Co
Priority to GB08507935A priority Critical patent/GB2172966A/en
Publication of GB8507935D0 publication Critical patent/GB8507935D0/en
Publication of GB2172966A publication Critical patent/GB2172966A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general

Abstract

Noise emission from an object or machine which produces noise is reduced by surrounding the object with a double-walled shield 10, 12, 14, 16 which has a vacuum 22 between its walls. The presence of the vacuum substantially reduces noise transmission across the walls. In an alternative embodiment the object is surrounded by shields secured to the object via seals, and the space between the object and the shields is evacuated. <IMAGE>

Description

SPECIFICATION Reduction of noise emission This invention relates to apparatus for reducing noise emission, for example from an internal combustion engine, by making use of the fact that sound transmission is substantially reduced in a vacuum.
According to a first aspect of the invention, there is provided apparatus for reducing noise emission from a noise-producing object, the apparatus comprising a double-walled shield adapted to surround the object, with an evacuated space enclosed between the shield walls.
The term "evacuated space" used in this specification refers to a space from which air has been evacuated to bring the pressure in the space to below atmospheric pressure. The effect of various different degrees of evacuation will be discussed below in this specification.
The shield may be made up of a number of different sections which can be assembled together around the object to produce a complete shield.
It is not essential to the invention that the object should be completely surrounded; however the effectiveness of the shielding will be improved the more completely the object is surrounded.
Where there are a number of shield sections, each section can be made of two parallel plates with a soft, air-tight seal between the plates to enclose the evacuated space. It is important that the seal should not of itself transmit noise producing vibrations.
If the shield sections are large, separators may be included in the evacuated space to keep the plates the required distance apart.
Again, these separators should not transmit vibrations across the shield sections.
According to a second aspect of the invention, there is provided apparatus for reducing noise emission from a noise-producing object, the apparatus comprising a plurality of shields, means for securing the shields to the object through seals which do not transmit vibration to any substantial extent, and means for evacuating the spaces between the shields and the object.
One particular application of the invention is in the noise insulation of internal combustion engines. The shield can be made with a first section to cover the top of the engine, a second section to cover the bottom of the engine, and a sleeve section to cover the central region of the engine between the top and the bottom. The sleeve section may be formed by a plurality of planar sections.
It is well known that sound transmission is reduced in a vacuum. Theoretical considerations lead to the conclusion that if the evacuated spaces in the shield are evacuated to about 270 millibars, then a reduction of the noise emitted engine of about 12dB could be achieved.
The invention will now be further described, by way of example, with reference to the accompanying drawing which shows a crosssection through a noise-reducing shield in accordance with the invention.
The shield shown is for use in reducing noise emission from an internal combustion engine. The shield includes a top cover 10, a bottom cover 12 and side wall covers 14 and 16. All the covers consist of inner and outer panels 18 and 20 which leave a space 22 between them and are sealed to each other at their edges by flexible, bonded, isolating seals 24. The space 22 is evacuated, for example to a pressure of 270 milibars. To prevent the panels 18 and 20 from being pressed against one another as a result of the internal/external pressure difference, flexible separators 26 bridge the panels.
In an alternative embodiment, which is not shown in the drawing, the object can be surrounded by shield sections which are attached directly to the object through soft seals which do not transmit vibration to any appreciable extent. In this way, the object itself can provide the structural support for the shield panels.
Power transmission from an enclosed engine could be via mechanical means or non-mechanical means such as hydraulic or hydrostatic devices.
1. Apparatus for reducing noise emission from a noise-producing object, the apparatus comprising a double-walled shield adapted to surround the object, with an evacuated space enclosed between the shield walls.
2. Apparatus as claimed in Claim 1, wherein the shield is made up of a number of different sections which can be assembled together around the object to produce a complete shield.
3. Apparatus as claimed in Claim 2, wherein each section is made of two parallel plates with a soft, air-tight seal between the plates to enclose the evacuated space.
4. Apparatus as claimed in Claim 3, wherein flexible separators are included in the evacuated space to keep the plates the required distance apart.
5. Apparatus as claimed in any one of the preceding claims for shielding an internal combustion engine and having a first section to cover the top of the engine, a second section to cover the bottom of the engine, and a sleeve section to cover the central region of the engine between the top and the bottom.
6. Apparatus as claimed in any preceding claim, wherein the evacuated spaces in the shield are evacuated to about 270 millibars.
7. Apparatus for reducing noise emission
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Reduction of noise emission This invention relates to apparatus for reducing noise emission, for example from an internal combustion engine, by making use of the fact that sound transmission is substantially reduced in a vacuum. According to a first aspect of the invention, there is provided apparatus for reducing noise emission from a noise-producing object, the apparatus comprising a double-walled shield adapted to surround the object, with an evacuated space enclosed between the shield walls. The term "evacuated space" used in this specification refers to a space from which air has been evacuated to bring the pressure in the space to below atmospheric pressure. The effect of various different degrees of evacuation will be discussed below in this specification. The shield may be made up of a number of different sections which can be assembled together around the object to produce a complete shield. It is not essential to the invention that the object should be completely surrounded; however the effectiveness of the shielding will be improved the more completely the object is surrounded. Where there are a number of shield sections, each section can be made of two parallel plates with a soft, air-tight seal between the plates to enclose the evacuated space. It is important that the seal should not of itself transmit noise producing vibrations. If the shield sections are large, separators may be included in the evacuated space to keep the plates the required distance apart. Again, these separators should not transmit vibrations across the shield sections. According to a second aspect of the invention, there is provided apparatus for reducing noise emission from a noise-producing object, the apparatus comprising a plurality of shields, means for securing the shields to the object through seals which do not transmit vibration to any substantial extent, and means for evacuating the spaces between the shields and the object. One particular application of the invention is in the noise insulation of internal combustion engines. The shield can be made with a first section to cover the top of the engine, a second section to cover the bottom of the engine, and a sleeve section to cover the central region of the engine between the top and the bottom. The sleeve section may be formed by a plurality of planar sections. It is well known that sound transmission is reduced in a vacuum. Theoretical considerations lead to the conclusion that if the evacuated spaces in the shield are evacuated to about 270 millibars, then a reduction of the noise emitted engine of about 12dB could be achieved. The invention will now be further described, by way of example, with reference to the accompanying drawing which shows a crosssection through a noise-reducing shield in accordance with the invention. The shield shown is for use in reducing noise emission from an internal combustion engine. The shield includes a top cover 10, a bottom cover 12 and side wall covers 14 and 16. All the covers consist of inner and outer panels 18 and 20 which leave a space 22 between them and are sealed to each other at their edges by flexible, bonded, isolating seals 24. The space 22 is evacuated, for example to a pressure of 270 milibars. To prevent the panels 18 and 20 from being pressed against one another as a result of the internal/external pressure difference, flexible separators 26 bridge the panels. In an alternative embodiment, which is not shown in the drawing, the object can be surrounded by shield sections which are attached directly to the object through soft seals which do not transmit vibration to any appreciable extent. In this way, the object itself can provide the structural support for the shield panels. Power transmission from an enclosed engine could be via mechanical means or non-mechanical means such as hydraulic or hydrostatic devices. CLAIMS
1. Apparatus for reducing noise emission from a noise-producing object, the apparatus comprising a double-walled shield adapted to surround the object, with an evacuated space enclosed between the shield walls.
2. Apparatus as claimed in Claim 1, wherein the shield is made up of a number of different sections which can be assembled together around the object to produce a complete shield.
3. Apparatus as claimed in Claim 2, wherein each section is made of two parallel plates with a soft, air-tight seal between the plates to enclose the evacuated space.
4. Apparatus as claimed in Claim 3, wherein flexible separators are included in the evacuated space to keep the plates the required distance apart.
5. Apparatus as claimed in any one of the preceding claims for shielding an internal combustion engine and having a first section to cover the top of the engine, a second section to cover the bottom of the engine, and a sleeve section to cover the central region of the engine between the top and the bottom.
6. Apparatus as claimed in any preceding claim, wherein the evacuated spaces in the shield are evacuated to about 270 millibars.
7. Apparatus for reducing noise emission from a noise-producing object, the apparatus comprising a plurality of shields, means for securing the shields to the object through seals which do not transmit vibration to any substantial extent, and means for evacuating the spaces between the shields and the object.
8. Apparatus for reducing noise emission from a noise producing object, substantially as herein described with reference to the accompanying drawing.
GB08507935A 1985-03-27 1985-03-27 Reduction of noise emission Withdrawn GB2172966A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08507935A GB2172966A (en) 1985-03-27 1985-03-27 Reduction of noise emission

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08507935A GB2172966A (en) 1985-03-27 1985-03-27 Reduction of noise emission

Publications (2)

Publication Number Publication Date
GB8507935D0 GB8507935D0 (en) 1985-05-01
GB2172966A true GB2172966A (en) 1986-10-01

Family

ID=10576714

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08507935A Withdrawn GB2172966A (en) 1985-03-27 1985-03-27 Reduction of noise emission

Country Status (1)

Country Link
GB (1) GB2172966A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010020268A1 (en) * 2008-08-19 2010-02-25 Siemens Aktiengesellschaft Noise-reducing device and method for reducing noise

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB372182A (en) * 1931-07-31 1932-05-05 Clifford Oakes Bower Improvements in heat and sound insulating materials
GB379389A (en) * 1931-06-01 1932-09-01 Albert Gerald Randle Buck Improvements in or relating to heat and sound insulating coverings
GB470835A (en) * 1934-11-17 1937-08-23 Genevieve Louise Dupuis Improvements in athermanous elements of construction, and applications thereof
GB730699A (en) * 1952-06-24 1955-05-25 Gen Electric Improvements in and relating to insulating panels
GB864709A (en) * 1956-11-15 1961-04-06 Sulzer Ag Deep cooling of gases
GB876163A (en) * 1959-02-10 1961-08-30 Yat Chuen Yuen Improvements in or relating to heat insulation panels
GB1447563A (en) * 1973-02-15 1976-08-25 Commissariat Energie Atomique Heat-insulating structures high voltage insulator a
GB1519216A (en) * 1974-09-30 1978-07-26 Siemens Ag Assembly comprising a member secured within a housing by means of a holding arrangement
GB2029546A (en) * 1978-09-06 1980-03-19 Messerschmitt Boelkow Blohm Vibration isolating element

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB379389A (en) * 1931-06-01 1932-09-01 Albert Gerald Randle Buck Improvements in or relating to heat and sound insulating coverings
GB372182A (en) * 1931-07-31 1932-05-05 Clifford Oakes Bower Improvements in heat and sound insulating materials
GB470835A (en) * 1934-11-17 1937-08-23 Genevieve Louise Dupuis Improvements in athermanous elements of construction, and applications thereof
GB730699A (en) * 1952-06-24 1955-05-25 Gen Electric Improvements in and relating to insulating panels
GB864709A (en) * 1956-11-15 1961-04-06 Sulzer Ag Deep cooling of gases
GB876163A (en) * 1959-02-10 1961-08-30 Yat Chuen Yuen Improvements in or relating to heat insulation panels
GB1447563A (en) * 1973-02-15 1976-08-25 Commissariat Energie Atomique Heat-insulating structures high voltage insulator a
GB1519216A (en) * 1974-09-30 1978-07-26 Siemens Ag Assembly comprising a member secured within a housing by means of a holding arrangement
GB2029546A (en) * 1978-09-06 1980-03-19 Messerschmitt Boelkow Blohm Vibration isolating element

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010020268A1 (en) * 2008-08-19 2010-02-25 Siemens Aktiengesellschaft Noise-reducing device and method for reducing noise
JP2012500416A (en) * 2008-08-19 2012-01-05 シーメンス アクチエンゲゼルシヤフト Noise reduced device and method for noise reduction
US8235169B2 (en) 2008-08-19 2012-08-07 Siemens Aktiengesellschaft Noise-reducing device and method for reducing noise
RU2479050C2 (en) * 2008-08-19 2013-04-10 Сименс Акциенгезелльшафт Device with decreased noise, and noise reduction method
KR101523808B1 (en) * 2008-08-19 2015-05-28 지멘스 악티엔게젤샤프트 Noise-reducing device and method for reducing noise

Also Published As

Publication number Publication date
GB8507935D0 (en) 1985-05-01

Similar Documents

Publication Publication Date Title
US20170179703A1 (en) Grommet and Method for Manufacturing Same
US3276539A (en) Sound isolating enclosure for internal combustion engine generator set
US20210164370A1 (en) Low noise enclosure
KR20080079994A (en) Rotary electric machine
MXPA06008429A (en) Compression unit, for pipe penetrations etc. adaptable to different frames.
GB2172966A (en) Reduction of noise emission
US6483778B1 (en) Systems and methods for passively compensating transducers
US3497638A (en) Explosion-proof acoustic device
GB2468778A (en) An enclosure for a fan
US3118125A (en) Underwater sound transducer with sealed liquid coupling chamber
JP3151483B2 (en) Vibration and sound insulation sleeve for air conditioning duct
JPH11330721A (en) Noise-proof cover
JP2002030942A (en) Vertical gas turbine device
JP2008301541A (en) Terminal box of motor
JP3508337B2 (en) Radiated sound reduction device
JPS6394033A (en) Drive constituted of reciprocating piston type internal combustion engine, transmission and output shaft
KR20090097628A (en) Soundroof device for compressor
RU1807290C (en) Pipe line with vacuum insulation
JPS6039920Y2 (en) sound insulation panel unit
JPH06213072A (en) Piston power machine or working machine
JPH0111946Y2 (en)
SU723653A1 (en) Aerodynamic noise silencer
JPS5855064Y2 (en) Sound insulation structure of engine vibration isolation support part
SU1404669A1 (en) Unit for fastening cylinder head cover shroud of internal combustion engine
SU1749404A1 (en) Acoustic panel

Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)