AU2001270480A1 - A Suction Apparatus with Noise Reduction Means - Google Patents
A Suction Apparatus with Noise Reduction MeansInfo
- Publication number
- AU2001270480A1 AU2001270480A1 AU2001270480A AU2001270480A AU2001270480A1 AU 2001270480 A1 AU2001270480 A1 AU 2001270480A1 AU 2001270480 A AU2001270480 A AU 2001270480A AU 2001270480 A AU2001270480 A AU 2001270480A AU 2001270480 A1 AU2001270480 A1 AU 2001270480A1
- Authority
- AU
- Australia
- Prior art keywords
- noise
- airflow
- suction apparatus
- indentations
- passage
- 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.)
- Granted
Links
Description
A SUCTION APPARATUS WITH NOISE . REDUCT ION MEANS ,
The present invention relates to a suction apparatus with noise reduction means in one or more airflow passages for reducing noise emission from an.airfldw generator or the like.
WO-A-97/13443 discloses a suction apparatus of the above-mentioned kind where the airflow generator is enclosed in a housing with an air inlet and an air outlet. The housing and the outlet are provided with sound-absorbing foamed plastic materials. This means that a significant noise reduction and a compact silencer may be obtained by providing the housing volume and at the outlet flow passages with a sound insulation material. Although this solution offers good dampening of the noise emission, this noise reduction solution comprises many different components and is therefore somewhat troublesome to assemble and consequently relatively expensive to manufacture.
Another solution to the noise reduction problem is known from EP-A-0 099 466, in which a vacuum cleaner is disclosed. This vacuum cleaner is provided with a sound- absorbing foam material around the motor housing and around the inlet and outlet passages lined with a sound-absorbing material. The outlet passages in this_ vacuum cleaner are designed with several changes in cross-section areas and with bends in order to provide changes in the acoustical properties that lead to reflections of the noise. The vacuum cleaner is moreover provided with a dampener in. front of the air inlet. Although this solution can provide an additional silencing effect, it is relatively extensive in dimensions and complex in design, making it cumbersome and relatively expensive to manufacture.
Another kind of noise reduction solution for a vacuum cleaner is known from DE-A-
40 37 442, in which an insert unit is inserted in the air outlet that directs the airflow through a serpentine- like flow-pattern. This noise reduction solution takes up a considerable amount of space and has a somewhat limited noise-reducing effect.
Also, as the air is repeatedly diverted in this manner, it may cause an undesired loss in pressure.
Another solution to noise reduction in a vacuum cleaner is known from EP-A-0 289 987, in which the exhaust passage is provided with a silencing passage consisting of a number of concentric air-tight tubular ribs defining a number of concentric exhaust airflow passages. A noise absorption material is provided along the upper walls of the passages. However, this solution is bulky in design and does not provide a satisfactory noise reduction.
Normally, the airflow generator is made up by an electric motor connected to a blower, i.e. a radial ventilator. When the vacuum cleaner is only used for dry suction cleaning, the primary airflow through the blower is also used for cooling the electric motor. However, when the vacuum cleaner is designed for use in a wet environment, the motor must be cooled by a separate cooling ventilator. Both the blower and the cooling ventilator cause emission of noise. The noise extends to the surroundings through the exhaust passage of the primary airflow and from the inlet and the exhaust air passages of the cooling air. The sound-absorbing material may be provided in the airflow passages or around the motor. However, the cooling ventilator is particularly difficult to silence in this manner due to the relatively short airflow passages. Furthermore, noise from the cooling ventilator is of a narrow band nature which makes it suitable for reduction by means of the described technique.
From JP 06 035478 A and JP 06 030860 A some other solutions concerning noise reduction of vacuum cleaners are known where a resonance type acoustic filter is provided. However, although this has a silencing effect their design is somewhat space consuming just as the production of these acoustic filters as an integral part of the vacuum cleaner housing is difficult and expensive.
On this basis, it is an object of the invention to provide a suction apparatus with noise reduction means which is simple to manufacture and with a compact structure so as
to allow for a compact design of the device in which the airflow generator is installed.
This object is achieved by a suction apparatus of the initially mentioned kind, wherein at least one airflow passage is provided with a plurality of indentations is arranged successively in the direction of the airflow, said indentations having a predetermined depth extending substantially perpendicularly to the general direction of the noise in the passage, and that the indentations are formed by providing protruding wall members on at least one side of the flow passage.
By the invention, a suction apparatus with noise reduction means is provided which is simple and efficient at reducing the noise and also inexpensive to manufacture. The noise is dampened as it extends in an airflow passage. A suction apparatus according to the invention is suitable for use in a vacuum cleaner with a separately cooled airflow generator by providing the airflow passages leading to the airflow generator and/or the ventilator with noise reduction means.
The principle at work by noise reduction according to the invention is that part of the noise that extends in the passage will extend into the indentations. At the bottom of the indentation, the noise will be reflected back into the passage. When the indentations have a depth corresponding to a 1/4 of the wave length of the noise, the noise wave reflected by the bottom of the indentation may interfere destructively with the noise in the passage. Hereby, the noise will be reduced at particular frequencies as the reflected noise will cancel out the noise in the passage, resulting in a considerable reduction in the noise level.
the wall members are provided perpendicular to the direction of the airflow. The effect of the noise reduction is optimised when the height or heights of the wall members or indentations is/are VΛ + n x > of the wave length of the noise to be reduced, where n is an integer number, including n=0. Hereby, the indentations may be particularly suitable for silencing noise at one or more predetermined frequencies by choosing an appropriate depth of the indentations. However, noise reduction not
only occurs at the predetermined frequencies but also at frequencies in close proximity thereto.
A plurality of indentations is arranged successively in the direction of the airflow, whereby an improved effect of the noise reduction is obtained in a simple manner and by a compact structure. Hereby, a noise filter may be integrally moulded in the parts making up the housing of the suction apparatus.
Preferably, the indentations are sub-diverted into sub-indentations in the traverse direction of the general direction of the airflow. The width of the indentations generally corresponds, to the length and is shorter than the depth. Hereby, it is ensured that the noise cannot travel "sideways" and fail to interfere with the remaining noise in the passage.
In a preferred embodiment, the indentations are formed by providing protruding wall members on at least one side of the flow passage. Hereby, the noise reduction means may be integrally formed in the housing members defining the airflow passages. When a plurality of indentations is required, a plurality of wall members is provided. In a particular embodiment, a grid of protruding wall members is provided in the airflow passage.
In a first embodiment, the airflow generator is separately cooled and provided with noise reduction means in one or more of the airflow passages. Alternatively, the airflow generator may be cooled by the primary airflow generated.
The invention will be described in detail below with reference to the accompanying drawings, in which
Fig. 1 is a schematic side view of a suction apparatus, fig. 2 is a principle illustration explaining the noise reduction principle according to the invention,
fig. 3 is a cross-section view of a suction apparatus according to a first embodiment of the invention, fig. 4 is a perspective view of a lid part of a suction apparatus with a noise reduction means according to a second embodiment of the invention, fig. 5 is a detailed schematic view incorporating a third embodiment of the noise reduction principle according to the invention, and fig. 6 is a detailed schematic view incorporating a fourth embodiment of the invention.
Figure 1 is a schematic view of a vacuum cleaner with a separately cooled airflow generator 1. The airflow generator 1 comprises an electric motor 5 connected to a blower 6 for generation of the primary suction airflow in the suction hose 10. On top, the electric motor 5 is equipped with a cooling fan 12 for cooling the motor 5.
Airflow passages 2, 3, 4 and 10 are provided in association with the blower 6 and the fan 12. The vacuum generated by the blower causes a primary airflow through the air hose 13. This air is exhausted through the primary air outlet passage 4.
Air for cooling of the electric motor 5 is drawn in through an inlet passage 2 by the fan 12. The utilised cooling air is exhausted through the cooling air outlet passage 3.
The noise generated by the airflow generator and/or by the velocity of the airflow travels through the passages 2, 3, 4, 10 from the noise-emitting source and into the surroundings irrespective of the general flow direction of the air (see arrow indications) in the passages.
In order to reduce this noise emission, one or more of the passages 2, 3, 4 may be provided with noise reduction means 7, 8. A noise reduction means according to the invention comprises a repeated structure such as shown in fig. 2. According to the invention, the noise reduction means involves a number of indentations 7 extending from one of the passage walls substantially perpendicularly to the direction of the noise in the particular passage 2, 3, 4. The indentations 7 are successively arranged in
the direction of the airflow and are separated by wall members 8. The indentations 7 are provided with a predetermined depth D that generally corresponds to the frequency of the noise in the passage to be silenced.
The depths of the indentations 7 may not necessarily be the same but may vary in order to reduce noise over a broader range of frequencies. This, however, is achieved at the expense of a less efficient noise reduction.
Part of the noise-travelling through the passage 2, 3, 4 will extend into the indentations 7. At the bottom of the indentations 7, the noise is reflected back into the passage 2, 3, 4. The reflected noise is delayed and is thus out of phase with the noise in the passage. This results in a destructive interference of the reflected noise and noise in the passage, generating a significant noise reduction. The noise-reducing effect is optimised when the noise has a frequency that corresponds to a indentation depth D of ! , 3A, 5/4, etc. of the wave length. Moreover, the effect is also improved if the indentations extend across the entire width of the passage and/or if several indentations are provided successively.
In a vacuum cleaner, the noise from the airflow generator is at its most intense level within the frequency range 1 kHz to 5 kHz. The cooling ventilator in a separately cooled motor scatters noise at a somewhat higher frequency within in the range of 2 kHz to 7 kHz.
In table 1, the preferred depths D of the indentations 7 are indicated for dampening noise within a relevant frequency range:
Table 1: Indentation depths and their corresponding frequencies of maximum dampening corresponding to lA, % or 5/4 of the wave length.
As it appears from table 1, the indentation depth D - or height of the wall members 8 - should preferably be between 17 mm and 86 mm. Increased depth is particularly advantageous, as it provides a dampening effect at more frequencies within the relevant frequency range.
A noise reduction means according to the invention is advantageous as the noise reduction may be integrated in passage defining parts of the vacuum cleaner and produced in a mouldable plastic material by an injection moulding process. This means that no extra sound-absorbing elements need to be placed in the vacuum cleaner.
A first embodiment of the invention is shown in figure 3, where a number of thin wall members 8 extend downwards from the top passage wall and into the airflow passages 2, 3. Hereby, a number of indentations 7 are formed between the thin wall members 8. The length of the thin wall members 8 (i.e. the depth D of the indentations 7) may vary, such as indicated in the figure, in order to adapt the noise reduction means to different frequencies.
In a second preferred embodiment, the top lid 9 of a vacuum cleaner is provided with a grid 11 of thin wall members 8 forming a number of cells acting as noise-reducing indentations 7, see fig. 4. The grid 11 may be integrally formed on the inside of the lid part 9. By using a grid, the indentations 7 are sub-divided so that noise is prevented from travelling "sideways" down into the grooves or indentations. The grid 11 is advantageous as it may be provided across the entire width of a passage wall, causing a significant noise reduction.
Other embodiments of the invention are shown in figures 5 and 6. In fig. 5, the noise reduction may be performed in a relative short air exhaust passage 4. In fig. 6, the
lower passage wall is provided with noise indentations separated by thin wall elements 14.
As it can be appreciated from the various embodiments, the principle of noise reduction according to the invention has a wide range of use and may be used to dampen noise in a vacuum cleaner which travels through a passage irrespective of its origin.
Claims (9)
1. A suction apparatus with noise reduction means in one or more airflow passages for reducing noise emission from an airflow generator or the like, c h a r a c t e r i s e d i n t h a t at least one airflow passage is provided with a plurality of indentations is arranged successively in the direction of the airflow, said indentations having a predetermined depth extending substantially perpendicularly to the general direction of the noise in the passage, and that the indentations are formed by providing protruding wall members on at least one side of the flow passage.
2. A suction apparatus according to claim 1, wherein the heights of each of the wall members are V-. + n x lA of the wave length of the noise to be reduced, where n is an integer number, including n=0.
3. A suction apparatus according to claim 2, wherein the height of all the wall members provided in an airflow passage is the same.
4. A suction apparatus according to claim 3, wherein the heights of the wall members provided in an air flow passage are different in order to reduce noise at different frequencies.
5. A suction apparatus according to any of the preceding claims, wherein the indentations are sub-diverted into sub-indentations in the traverse direction of the direction of the noise.
6. A suction apparatus according to any of the preceding claims, wherein a plurality of wall members of different thickness are provided.
7. A suction apparatus according to any of the preceding claims, wherein the wall members are provided perpendicular to the direction of the airflow.
8. A suction apparatus according to any of preceding claims, wherein a grid of protruding wall members is provided in the airflow passage.
9. A suction apparatus according to any of the preceding claims, wherein the airflow generator is separately cooled.
1/3
Figl
Fig 2 2/3
Fig 3
Fig 4 3/3
Fig 5
Fig 6
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP00202505.4 | 2000-07-14 | ||
EP00202505A EP1172059A1 (en) | 2000-07-14 | 2000-07-14 | A suction apparatus with noise reduction means |
PCT/DK2001/000465 WO2002005697A1 (en) | 2000-07-14 | 2001-07-03 | A suction apparatus with noise reducion means |
Publications (2)
Publication Number | Publication Date |
---|---|
AU2001270480A1 true AU2001270480A1 (en) | 2002-05-02 |
AU2001270480B2 AU2001270480B2 (en) | 2005-01-13 |
Family
ID=8171803
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
AU7048001A Pending AU7048001A (en) | 2000-07-14 | 2001-07-03 | A suction apparatus with noise reducion means |
AU2001270480A Ceased AU2001270480B2 (en) | 2000-07-14 | 2001-07-03 | A Suction Apparatus with Noise Reduction Means |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
AU7048001A Pending AU7048001A (en) | 2000-07-14 | 2001-07-03 | A suction apparatus with noise reducion means |
Country Status (8)
Country | Link |
---|---|
US (1) | US7337876B2 (en) |
EP (2) | EP1172059A1 (en) |
AT (1) | ATE348561T1 (en) |
AU (2) | AU7048001A (en) |
DE (1) | DE60125367T2 (en) |
DK (1) | DK1303209T3 (en) |
ES (1) | ES2278759T3 (en) |
WO (1) | WO2002005697A1 (en) |
Families Citing this family (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA2545977A1 (en) * | 2005-05-09 | 2006-11-09 | Emerson Electric Co. | Noise-reduced vacuum appliance |
DE102006022833A1 (en) * | 2006-05-16 | 2007-11-22 | BSH Bosch und Siemens Hausgeräte GmbH | Vacuum cleaner with at least one centrifugal separator |
US7631725B2 (en) * | 2006-10-06 | 2009-12-15 | Ingersoll Rand Company | Exhaust system |
SE533268C2 (en) | 2008-12-17 | 2010-08-03 | Electrolux Ab | Vacuum cleaner |
US20100246880A1 (en) * | 2009-03-30 | 2010-09-30 | Oxford J Craig | Method and apparatus for enhanced stimulation of the limbic auditory response |
CN102727134A (en) * | 2011-04-06 | 2012-10-17 | 乐金电子(天津)电器有限公司 | Noise reduction structure of casing cover of dust-absorbing motor |
CN102327878A (en) * | 2011-09-22 | 2012-01-25 | 上海亿力电器有限公司 | Low-noise high-pressure cleaning machine |
US9402517B2 (en) | 2012-10-09 | 2016-08-02 | Koninklijke Philips N.V. | Exhaust grille |
US9752494B2 (en) | 2013-03-15 | 2017-09-05 | Kohler Co. | Noise suppression systems |
US9388731B2 (en) * | 2013-03-15 | 2016-07-12 | Kohler Co. | Noise suppression system |
US9169750B2 (en) * | 2013-08-17 | 2015-10-27 | ESI Energy Solutions, LLC. | Fluid flow noise mitigation structure and method |
WO2016112996A1 (en) | 2015-01-13 | 2016-07-21 | Alfred Kärcher Gmbh & Co. Kg | Suction device and method for operating a suction device |
DE102015100426A1 (en) * | 2015-01-13 | 2016-07-14 | Alfred Kärcher Gmbh & Co. Kg | Cleaning device and method for reducing noise in a cleaning device |
EP3244784B1 (en) * | 2015-01-13 | 2021-10-06 | Alfred Kärcher SE & Co. KG | Suction device |
CN104863681A (en) * | 2015-04-13 | 2015-08-26 | 成都陵川特种工业有限责任公司 | Exhaust pipe silencing method |
DE102017111910A1 (en) | 2017-05-31 | 2018-12-06 | Alfred Kärcher SE & Co. KG | cleaner |
CN114046273B (en) * | 2021-11-26 | 2023-05-02 | 西安科技大学 | Noise control method of local ventilator for coal mine |
Family Cites Families (27)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2546707A (en) * | 1947-07-05 | 1951-03-27 | Wallingford John | Baffle type exhaust silencer |
US3773141A (en) * | 1972-09-22 | 1973-11-20 | G Thien | Sound-proofing wall-forming structural element |
JPS5170971A (en) * | 1974-12-17 | 1976-06-19 | Matsushita Electric Ind Co Ltd | SHINKUSOJIKI |
DK142710B (en) * | 1977-11-10 | 1980-12-29 | Elektronikcentralen | Sound absorbing structure. |
US4346781A (en) * | 1978-11-16 | 1982-08-31 | Massachusetts Institute Of Technology | Lined-duct acoustic filter |
GB2049887B (en) * | 1979-05-23 | 1982-12-01 | Coal Industry Patents Ltd | Acoustic liner for attenuating noise |
JPS6217675Y2 (en) * | 1980-12-05 | 1987-05-07 | ||
US4418443A (en) * | 1981-12-07 | 1983-12-06 | Breuer Electric Mfg. Co. | Noise suppressor for vacuum sweepers and the like |
DE3225258C2 (en) * | 1982-07-06 | 1985-11-28 | Guido Oberdorfer Wap-Maschinen, 7919 Bellenberg | Vacuum cleaner |
US4821839A (en) * | 1987-04-10 | 1989-04-18 | Rpg Diffusor Systems, Inc. | Sound absorbing diffusor |
JPH0665332B2 (en) * | 1987-05-06 | 1994-08-24 | 株式会社日立製作所 | Vacuum cleaner |
US4944362A (en) * | 1988-11-25 | 1990-07-31 | General Electric Company | Closed cavity noise suppressor |
US4970753A (en) * | 1990-02-23 | 1990-11-20 | Ryobi Motor Products Corp. | Vacuum cleaner noise reducing arrangement |
US5129793A (en) * | 1990-10-24 | 1992-07-14 | Copeland Corporation | Suction muffler |
JP2574573B2 (en) * | 1991-10-18 | 1997-01-22 | 松下精工株式会社 | Ventilation fan |
JPH05199955A (en) * | 1992-01-27 | 1993-08-10 | Tokyo Electric Co Ltd | Vacuum cleaner |
JP3154816B2 (en) * | 1992-06-26 | 2001-04-09 | 東芝テック株式会社 | Electric vacuum cleaner |
JPH0630860A (en) * | 1992-06-26 | 1994-02-08 | Tokyo Electric Co Ltd | Vacuum cleaner |
US5276291A (en) * | 1992-07-10 | 1994-01-04 | Norris Thomas R | Acoustic muffler for high volume fluid flow utilizing Heimholtz resonators with low flow resistance path |
SE511890C2 (en) * | 1993-02-10 | 1999-12-13 | Dalloz Safety Ab | Ear protector with increased sound attenuation |
CH690143A5 (en) * | 1995-01-27 | 2000-05-15 | Rieter Automotive Int Ag | Lambda / 4 sound absorbers. |
AU707268B2 (en) * | 1995-10-10 | 1999-07-08 | Nilfisk A/S | A silencer for a suction cleaner |
US6116375A (en) * | 1995-11-16 | 2000-09-12 | Lorch; Frederick A. | Acoustic resonator |
US5817990A (en) * | 1996-07-25 | 1998-10-06 | Aaf International | Wall structure for sound attenuating apparatus |
AUPO873297A0 (en) * | 1997-08-22 | 1997-09-18 | University Of Sydney, The | A quarter-wave resonator system for the attenuation of noise entering buildings |
DE19804567C2 (en) * | 1998-02-05 | 2003-12-11 | Woco Franz Josef Wolf & Co Gmbh | Surface absorber for sound waves and use |
AUPP712998A0 (en) | 1998-11-16 | 1998-12-10 | Field, Christopher David | Noise attenuation device |
-
2000
- 2000-07-14 EP EP00202505A patent/EP1172059A1/en not_active Withdrawn
-
2001
- 2001-07-03 AT AT01949276T patent/ATE348561T1/en not_active IP Right Cessation
- 2001-07-03 EP EP01949276A patent/EP1303209B1/en not_active Expired - Lifetime
- 2001-07-03 AU AU7048001A patent/AU7048001A/en active Pending
- 2001-07-03 DK DK01949276T patent/DK1303209T3/en active
- 2001-07-03 ES ES01949276T patent/ES2278759T3/en not_active Expired - Lifetime
- 2001-07-03 DE DE60125367T patent/DE60125367T2/en not_active Expired - Lifetime
- 2001-07-03 WO PCT/DK2001/000465 patent/WO2002005697A1/en active IP Right Grant
- 2001-07-03 AU AU2001270480A patent/AU2001270480B2/en not_active Ceased
- 2001-07-03 US US10/333,041 patent/US7337876B2/en not_active Expired - Lifetime
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP1303209B1 (en) | A suction apparatus with noise reducion means | |
AU2001270480A1 (en) | A Suction Apparatus with Noise Reduction Means | |
US5720074A (en) | Vacuum cleaner having a noise reduction system | |
CA2200559C (en) | High volume, high performance, ultra quiet vacuum cleaner | |
JP2009100840A (en) | Electric blower and electric vacuum cleaner using it | |
US20060213022A1 (en) | Exhausting apparatus of motor assembly and vacuum cleaner having the same | |
US8943644B2 (en) | Vacuum cleaner | |
KR100809738B1 (en) | Vacuum cleaner | |
EP0798468B1 (en) | Electric fan | |
EP1723883A2 (en) | Exhausting apparatus of a motor assembly and a vacuum cleaner having the same | |
JPH10211128A (en) | Vacuum cleaner | |
JP3319646B2 (en) | Vacuum cleaner silencer | |
JP4862608B2 (en) | Electric blower and electric vacuum cleaner using the same | |
JPH0630860A (en) | Vacuum cleaner | |
CN115089047A (en) | Household dust collector equipped with silencing cavity | |
JP4839770B2 (en) | Electric blower and electric vacuum cleaner using the same | |
JP3154816B2 (en) | Electric vacuum cleaner | |
JP4911179B2 (en) | Vacuum cleaner | |
JPH0496721A (en) | Vacuum cleaner | |
EP0683639B1 (en) | Ultra quiet vacuum cleaner | |
KR100236012B1 (en) | Device for decreasing the noise of vacuum cleaner | |
JPS6240159Y2 (en) | ||
JP2009011615A (en) | Motor-driven blower and vacuum cleaner using the same | |
KR200143215Y1 (en) | Anti-noise reinforcement structure of muffler chamber system in a vacuum cleaner | |
JPH08164096A (en) | Vacuum cleaner |