EP0839287A1 - Silencer for the discharge from a centrifugal blower - Google Patents
Silencer for the discharge from a centrifugal blowerInfo
- Publication number
- EP0839287A1 EP0839287A1 EP96915242A EP96915242A EP0839287A1 EP 0839287 A1 EP0839287 A1 EP 0839287A1 EP 96915242 A EP96915242 A EP 96915242A EP 96915242 A EP96915242 A EP 96915242A EP 0839287 A1 EP0839287 A1 EP 0839287A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- silencer
- slots
- blower
- outlet
- section
- 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- Withdrawn
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
- F04D29/661—Combating cavitation, whirls, noise, vibration or the like; Balancing especially adapted for elastic fluid pumps
- F04D29/663—Sound attenuation
- F04D29/664—Sound attenuation by means of sound absorbing material
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
- F24F13/24—Means for preventing or suppressing noise
Definitions
- the present invention is related to a silencer for the s discharge of a centrifugal blower, according to the preamble of the claims.
- Centrifugal blowers of the known type comprise a discharge having a constriction in the shape of a tongue formed in such a way that the effective discharge opening only covers o 60-70 % of the total cross section.
- This constriction provides the medium from the blower with a velocity profile having an oblique distribution across the cross section of the discharge, as can be seen from figure 1 which schematically discloses the discharge velocity along the cross section in four different s distances from the discharge. As can be seen from figure 1 in the drawing, the highest velocity exists approximately near the circumference of the blower wheel.
- Known silencers for centrifugal blowers lead the air flow from the blower into a box which normally is constructed o with a forechamber, sound absorbing plates at a distance from each other in such a way that channels are established between them, as well as a second chamber before the discharge.
- the purpose of the forechamber is to distribute the air evenly to all slots between the plates, before the air enters the slots.
- Such 5 structures necessarily are voluminous and the costs increases correspondingly for production as well as installation.
- the flow medium will experience a pressure loss in the chamber due to loss of velocity pressure.
- the flow medium also will experience further losses due to friction and 0 impacts on the different parts of the structure.
- figure 1 schematically the distribution of the velocity across the cross section of the centrifugal blower at four different distances from the discharge in a traditional blower
- figure 2 discloses schematically the silencer according to the present invention secured to a centrifugal blower, seen in a vertical section
- figure 3 discloses the blower in figure 2 in perspective
- figure 4 discloses a front view of the blower in figure 3
- figure 5 discloses a vertical section V in a slot in the silencer in figure 3
- figure 6 discloses a horizontal section VI through the silencer in figure 3.
- the medium gains the pressure drop which the medium has accumulated on its way through the silencer, as the velocity pressure is transformed to static pressure, corresponding to the friction pressure through the silencer.
- the conditions for the outlet of the silencer are optimized and additionally the velocity profile is completely equalized through the silencer. Also the silencing effect is improved.
- Figures 2-6 disclose one embodiment of the silencer according to the present invention, having vertically arranged sound dampening slots 5 for thoroughgoing flow of the medium. Depending of the local arrangement and other parameters, these slots may be arranged vertically or horizontally.
- the silencer preferably may have a shape as disclosed in figure 5 where the connecting funnel 6 ensures that the inlet of the silencer completely corresponds with the outlet 2 of the centrifugal blower. In this way negative effects from the tongue 7 of the centrifugal blower are avoided.
- the silencer has a shape according the diffusor principle where two slots 5 extend from the outlet 2 of the blower 1 to the outlet of the silencer.
- a thin partition wall 4 is arranged between the slots 5 and a surrounding isolating material 3 covers the vertical slots 5 above and below and at the sides.
- the air velocity is set to approximately 20 m/s and to establish a transition between the outlet 2 of the centrifugal blower and the dampening portion of the silencer thereby establishing a diffusor effect.
- the transition is made in such a way that a constant total cross section is maintained from the inlet of the silencer, by a s tapered portion 8, whereby an increased sound dampening effect is achieved.
- Constant cross section in the transition area is achieved by increasing the width of the transition wall 4 and thereby make the width of the slots 5 smaller along the tapered o portion 8 and at the same time increase the height of the slots 5.
- the entire partition wall 4 may as such be tapered along its length from silencer inlet to its outlet, or the partition wall may be a parallel prolongation of the tapered s portion 8.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
Silencer for connection to the outlet of a centrifugal blower, comprising slots for the thoroughgoing flow from the blower, surrounded by sound absorbing material, the silencer thereby being arranged in such a way that the flow from the blower enters the silencer slots being arranged at the smallest cross section opening of the centrifugal blower, e.g. at the cross section of the tongue (7) of the blower, and that a partition wall (4) being arranged in the silencer between two slots, the partition wall (4) having increasing thickness from the inlet to the outlet thereby ensuring that the total flow cross section is substantially constant from the inlet to the outlet of the silencer.
Description
Silencer for the Discharge from a Centrifugal Blower
The present invention is related to a silencer for the s discharge of a centrifugal blower, according to the preamble of the claims.
Centrifugal blowers of the known type comprise a discharge having a constriction in the shape of a tongue formed in such a way that the effective discharge opening only covers o 60-70 % of the total cross section. This constriction provides the medium from the blower with a velocity profile having an oblique distribution across the cross section of the discharge, as can be seen from figure 1 which schematically discloses the discharge velocity along the cross section in four different s distances from the discharge. As can be seen from figure 1 in the drawing, the highest velocity exists approximately near the circumference of the blower wheel.
Known silencers for centrifugal blowers lead the air flow from the blower into a box which normally is constructed o with a forechamber, sound absorbing plates at a distance from each other in such a way that channels are established between them, as well as a second chamber before the discharge. The purpose of the forechamber is to distribute the air evenly to all slots between the plates, before the air enters the slots. Such 5 structures necessarily are voluminous and the costs increases correspondingly for production as well as installation.
Furthermore, the flow medium will experience a pressure loss in the chamber due to loss of velocity pressure. The flow medium also will experience further losses due to friction and 0 impacts on the different parts of the structure.
Based on the above, it is an object for the present invention to provide a silencer for a centrifugal blower having the same properties for the sound dampening as known embodiments, but with a substantially smaller need for space, a strongly cost 5 reduction in the construction and which also gives substantially smaller pressure loss for the medium, as friction loss as well as impact loss.
The above is achieved with the silencer according to the present invention as defined with the features stated in the
claims.
The drawing discloses in figure 1 schematically the distribution of the velocity across the cross section of the centrifugal blower at four different distances from the discharge in a traditional blower, figure 2 discloses schematically the silencer according to the present invention secured to a centrifugal blower, seen in a vertical section, figure 3 discloses the blower in figure 2 in perspective, figure 4 discloses a front view of the blower in figure 3, figure 5 discloses a vertical section V in a slot in the silencer in figure 3 and figure 6 discloses a horizontal section VI through the silencer in figure 3.
With the silencer according to the present invention is achieved that the medium gains the pressure drop which the medium has accumulated on its way through the silencer, as the velocity pressure is transformed to static pressure, corresponding to the friction pressure through the silencer. The conditions for the outlet of the silencer are optimized and additionally the velocity profile is completely equalized through the silencer. Also the silencing effect is improved.
Figures 2-6 disclose one embodiment of the silencer according to the present invention, having vertically arranged sound dampening slots 5 for thoroughgoing flow of the medium. Depending of the local arrangement and other parameters, these slots may be arranged vertically or horizontally.
The silencer preferably may have a shape as disclosed in figure 5 where the connecting funnel 6 ensures that the inlet of the silencer completely corresponds with the outlet 2 of the centrifugal blower. In this way negative effects from the tongue 7 of the centrifugal blower are avoided.
The silencer has a shape according the diffusor principle where two slots 5 extend from the outlet 2 of the blower 1 to the outlet of the silencer. A thin partition wall 4 is arranged between the slots 5 and a surrounding isolating material 3 covers the vertical slots 5 above and below and at the sides.
To achieve as little losses as possible for the connection between the blower and the silencer, the air velocity is set to approximately 20 m/s and to establish a transition
between the outlet 2 of the centrifugal blower and the dampening portion of the silencer thereby establishing a diffusor effect. The transition is made in such a way that a constant total cross section is maintained from the inlet of the silencer, by a s tapered portion 8, whereby an increased sound dampening effect is achieved.
Constant cross section in the transition area is achieved by increasing the width of the transition wall 4 and thereby make the width of the slots 5 smaller along the tapered o portion 8 and at the same time increase the height of the slots 5.
The entire partition wall 4 may as such be tapered along its length from silencer inlet to its outlet, or the partition wall may be a parallel prolongation of the tapered s portion 8.
0
5
0
5
Claims
Patent claims
5 1. Silencer for connection to the outlet of a centri¬ fugal blower, comprising slots for the thoroughgoing flow from the blower, surrounded by sound absorbing material, CHARACTERIZED IN the silencer being arranged in such a way that the flow from the blower enters the silencer slots being arranged at the o smallest cross section opening of the centrifugal blower, e.g. at the cross section of the tongue (7) of the blower, and that a partition wall (4) being arranged in the silencer between two slots, the partition wall (4) having increasing thickness from the inlet to the outlet thereby ensuring that the total flow s cross section is substantially constant from the inlet to the outlet of the silencer.
2. Silencer according to preceding claims, CHARAC¬ TERIZED IN the transition comprising an tapered portion (8) at the outlet (2) increasing its thickness to the thickness of the o transition wall (4) between the two slots (5) in such a way that the width of the slot opening decreases due to the angle of the tapered portion substantially corresponding to the increase of the height of the slot opening, due to the vertical opening angle of the slots only along a first portion (8) of the wall length. 5 3. Silencer according to preceding claims, CHARAC¬
TERIZED IN the slots (5) being arranged vertically.
0
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Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO951826A NO301787B1 (en) | 1995-05-09 | 1995-05-09 | Muffler for centrifugal fan |
| NO951826 | 1995-05-09 | ||
| PCT/NO1996/000111 WO1996035879A1 (en) | 1995-05-09 | 1996-05-08 | Silencer for the discharge from a centrifugal blower |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP0839287A1 true EP0839287A1 (en) | 1998-05-06 |
Family
ID=19898190
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP96915242A Withdrawn EP0839287A1 (en) | 1995-05-09 | 1996-05-08 | Silencer for the discharge from a centrifugal blower |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0839287A1 (en) |
| AU (1) | AU5706296A (en) |
| NO (1) | NO301787B1 (en) |
| WO (1) | WO1996035879A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL1008137C2 (en) * | 1998-01-27 | 1999-08-02 | Zwaan Adrianus J | Wall-mounted ventilation unit with internal electric fan |
| FR2881191B1 (en) * | 2005-01-25 | 2010-10-15 | Renault Sas | DEVICE FOR SUPPLYING AN INTERNAL COMBUSTION ENGINE COMPRISING A PULSATION DAMPING CHAMBER |
| CN109026843A (en) * | 2018-09-14 | 2018-12-18 | 珠海格力电器股份有限公司 | Centrifugal compressor and its exhaust volute |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB783055A (en) * | 1955-03-01 | 1957-09-18 | Werner Genest Ges Fuer Isolier | Improvements in or relating to sound absorbers for induction and exhaust ducts of power unit and compressor testing stations |
| DE2406458A1 (en) * | 1974-02-12 | 1975-08-14 | Wilhelm Gebhardt | Roof fan for outlet end of vent - with silencer on pressure side forming part of housing |
| DE3401209A1 (en) * | 1984-01-14 | 1985-07-25 | ASEA AB, Västerås | Cooling configuration for cooling a medium |
-
1995
- 1995-05-09 NO NO951826A patent/NO301787B1/en unknown
-
1996
- 1996-05-08 AU AU57062/96A patent/AU5706296A/en not_active Abandoned
- 1996-05-08 WO PCT/NO1996/000111 patent/WO1996035879A1/en not_active Application Discontinuation
- 1996-05-08 EP EP96915242A patent/EP0839287A1/en not_active Withdrawn
Non-Patent Citations (1)
| Title |
|---|
| See references of WO9635879A1 * |
Also Published As
| Publication number | Publication date |
|---|---|
| WO1996035879A1 (en) | 1996-11-14 |
| NO951826D0 (en) | 1995-05-09 |
| AU5706296A (en) | 1996-11-29 |
| NO301787B1 (en) | 1997-12-08 |
| NO951826L (en) | 1996-11-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
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| 17P | Request for examination filed |
Effective date: 19971120 |
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| AK | Designated contracting states |
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| AX | Request for extension of the european patent |
Free format text: AL PAYMENT 971118;LT PAYMENT 971118;LV PAYMENT 971118;SI PAYMENT 971118 |
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| 17Q | First examination report despatched |
Effective date: 20011218 |
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| GRAG | Despatch of communication of intention to grant |
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| GRAG | Despatch of communication of intention to grant |
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| GRAH | Despatch of communication of intention to grant a patent |
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| STAA | Information on the status of an ep patent application or granted ep patent |
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| 18D | Application deemed to be withdrawn |
Effective date: 20021217 |