(19)
(11)EP 1 216 360 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
25.01.2006 Bulletin 2006/04

(21)Application number: 99948016.3

(22)Date of filing:  30.09.1999
(51)International Patent Classification (IPC): 
F04D 29/42(2006.01)
F04D 29/66(2006.01)
B01D 46/10(2006.01)
F24F 7/007(2006.01)
F24F 3/16(2006.01)
(86)International application number:
PCT/SG1999/000097
(87)International publication number:
WO 2001/023764 (05.04.2001 Gazette  2001/14)

(54)

APPARATUS FOR MINIMISING NOISE IN A FAN UNIT

VORRICHTUNG ZUR GERÄUSCHVERMINDERUNG EINES GEBLÄSES

APPAREIL DE REDUCTION DE BRUIT DANS UNE UNITE DE VENTILATEUR


(84)Designated Contracting States:
DE FR IT

(43)Date of publication of application:
26.06.2002 Bulletin 2002/26

(73)Proprietor: Kyodo-Allied Industries Ltd
Singapore 628771 (SG)

(72)Inventor:
  • LEE, Zong, Tang
    Singapore 628771 (SG)

(74)Representative: Lamb, Martin John Carstairs et al
Marks & Clerk 90 Long Acre
London WC2E 9RA
London WC2E 9RA (GB)


(56)References cited: : 
WO-A1-99/11984
US-A- 4 768 424
  
  • PARKER S.P.: 'Dictionary of scientific and technical terms', MCGRAW-HILL BOOK COMPANY * page 803 *
  
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description


[0001] The present invention relates to an apparatus for minimising noise from air moving devices, such as fans, air blowers etc. In particular, the present invention relates to a fan unit which may be used with a filter.

[0002] It is common to control the number of particles in the air in a modern production and/or testing facility in order to ensure the quality of its output. Whether be it for wafer dies, compact discs or memory disk drives, effective fan filter units are needed to not only keep the particles contents within the clean room at acceptable levels but also to circulate the air to maintain a pleasant working environment for the clean room workers.

[0003] However, such powerful fan filter units create excessive noise. It is known to use insulation materials to line along a conduit to or within the fan filter units to reduce noise. However, over time, the particles or fiber from the insulation material are dislodged from the surface and contaminate the clean room facility.

[0004] The problem associated with fan filter noise is particularly exacerbated in confined spaces or enclosures such as a multi-story water fabrication plant. By confined space, the present invention envisages the height of the ceiling to be less than three meters. Low ceilings cause noise from fan filter unit to be particularly pronounced.

[0005] Previously, an apparatus which minimises noise from a fan filter unit has been suggested by the current applicant in WO 99/11984. However, the S-shaped baffles of this earlier design only allow the design to be used with fans which rotate with a predetermined orientation, i.e. either only clockwise or anti-clockwise.

[0006] The present invention attempts to address the above problem of reducing noise associated with a fan unit, without increasing contamination caused by the unit. The present invention also attempts to increase the power efficiency of such a fan unit. The invention also can be used regardless of whether the fan rotates in an anti-clockwise or clockwise direction.

[0007] US4768424 discloses a fan unit for withdrawing air from a room and discharging it over a roof. There is an impeller located between centrosymmetric wall sections which may be of various design.

[0008] The present invention provides a fan unit comprising;
a fan blower configured to emit air in a plurality of directions in an air flow plane;
a pair of guides disposed on opposite sides of said fan blower in the said air flow plane to guide the flow of air between the two guides each guide having an indent opposite said fan to accommodate said fan ;
each guide being symmetric about a symmetry plane perpendicular to the air flow plane formed through the centre of the fan and at least one of the indents; characterized in that the fan unit further comprises;
baffles at each end of the guides to direct air out of the unit, the baffles being inclined with respect to the airflow plane.

[0009] The symmetric shape of each guide with respect to the fan allows the guides to be used in the same positions regardless of the direction of orientation of the fan.

[0010] In addition to the indent, the guides are preferably provided with protrusions on either side of the indent wherein the protrusions extend towards the opposite guide. Thus, each guide has a substantially "W"- type shape. Preferably, the guide has a smoothly varying profile at the indent and, more preferably at the protrusions. However, the noise-reduction properties may be partially achieved, using a guide with straight sections.

[0011] The configuration of the guides reduces the noise from the fan unit. Also, the configuration of the guides enhances the velocity of air circulating in the unit. Hence, a more efficient fan unit can be produced as a lower power can be used to drive the fan to achieve the same circulating air velocity.

[0012] The air in the fan filter unit moves between the two guides. Baffles are preferably located at either end of the guides. The baffles are provided to direct the air away from the fan and out of the fan unit.

[0013] There are a pair of baffles at each end of the guides. There is an upper baffle and a lower baffle with the lower baffle beneath the upper baffle. The vertical direction is taken to be the direction which is perpendicular to the plane of air emitted from the fan. The baffles are preferably inclined with respect to one another, such that the distance between the baffles decreases in a direction away from the fan. Preferably, the upper baffles are disposed at an angle of at least 40° and at most 60° to the direction of the plane of air. More preferably, they are arranged at an angle of about 45° to the air flow plane.

[0014] The lower baffles are preferably arranged at an angle of at least 5° and at most 15° to the direction of the plane of air more preferably at about 10° to the plane of air.

[0015] The baffles are located such that as the air leaves the guides, the air is reflected by the upper baffle onto the lower baffle, the lower baffle is positioned to direct the air out of an outlet.

[0016] Preferably, the fan unit comprises a housing which has a base plate and an upper housing located above the base plate, the fan and guides being located between the upper housing and lower base plate, the unit having side sections which may be integral with the upper housing. The side sections being locate at opposite ends of the guides, such that the baffles lie between the side sections and the ends of the guides.

[0017] In the above configuration, the base plate will preferably be located relative to the housing such that the separation between the base palate and the upper surface of the upper housing is smaller that the distance which the side sections protrude from the upper surface of the housing. There is also a gap between the side sections and the base plate to form the outlet of the fan unit. The gap between the side section of the housing and the base plate should, ideally be large enough to accommodate at least a part of the lower baffle in this gap.

[0018] The fan unit of the present invention is primarily intended for use in a clean room. Therefore, the unit preferably comprises a filter. Generally, this filter will be located below the base plate of the unit.

[0019] The guides and/or the baffles of the present invention will preferably be made from a solid material, more preferably a metal. The guides and/or baffles may also be perforated.

[0020] The present invention will now be described with reference to the following nonlimiting embodiments which:

Figure. I is a exploded, right side, perspective elevational view of an embodiment of the present invention;

Figure. 2 is a front, cross sectional elevational view of the embodiment of Figure 1;

Figure. 3 is a top, plan elevational view of section A-A in Figure 2;

Figure. 4 shows the locations in the fan filter unit where the airflow velocities were measured for Figure 5;

Figure. 5 is a chart comparing the average velocity of airflow and noise level of a fan filter unit with and without the present invention over a range external static pressures (measured in mmAq) for different airflow condition.



[0021] Figure 1 shows an exploded view of the fan filler unit. For clarity, the filter is not shown. A rotatable fan blower 12 is located on a base plate 14. A mounting plate 20 for the fan blower 12 is located on an opposing side of the base plate 14 to the fan blower 12.

[0022] The fan blower 12 is located within a housing which is formed from the base plate 14, an upper housing 16 and end sections 22. The upper housing 16 has an air inlet 18 located in its centre. Such that in use, the air inlet is located above fan blower 12. Fan blower 12 is a conventional type blower. It is configured to be rotated by a motor (not shown) which will be located on opposing side of base plate 14 to the fan blower 12. As the fan blower rotates, it air is drawn through inlet 18 and expelled air in direction tangential to the rotation direction of the fan blower 12.

[0023] The fan blower is also provided with guides 24A and 24B which are located on either side of the fan blower 12 and are disposed within the stream of emitted air from fan blower 12. Each guide is provided with an indent 25A and 25B which, when the guide is in position, accommodate the shape of the fan blower 12. On either side of the indent are protrusions 27A and 27B. Each of the protrusions extends towards the opposite guide 24.

[0024] Upper baffles 26A and 26B and lower baffles 28A and 28B are provided at either end of the unit, such that the baffles are disposed between fan blower 12 / guides 24A and 24B and the end section 22.

[0025] The guides 24A, 24B are inclined with respect to one another such that the distance between the guides 24A, 24B decreases away from the fan blower. Essentially, the guides from a substantially V-shaped structure where the apex of the V is pointing towards the end sections 22.

[0026] Figure 2 shows the direction of air flow within the fan filter of Figure 1. As previously described, air is drawn in through inlet 18 by the rotation of fan blower 12. Fan blower 12 is located on base plate 14. The rotation of the fan blower forces air away from the fan blower and into the baffles 26A and 26B and 28A and 28B. The direction of the baffles turns the air from traveling away from the blower which is located on the base plate to traveling out of the outlet 19 which is located beneath the base plate 14. The air then travels through filter 32 which is located underneath opening 19.

[0027] Figure 3 shows a plan view of the constructed fan filter unit of Figures 1 and 2. It can be clearly seen that the fan blower 12 is located between guides 24A and 24B and is accommodated within indents 25A and 25B of the guides 24A and 24B. The shape of the protrusions 27A and 27B which extend towards the complementary protrusions in the opposite guide should also be noted.

[0028] The guides 24A, 24B are contoured to receive the discharged air from the fan blower 12 (shown in dotted circle) and guide the flow of air with minimum amount of turbulence towards the baffles 26 and 28. As this is a top View, the lower baffle 28 is not clearly shown.

[0029] The upper baffles 26 are disposed at angles of about 45° to the plane of air which is emitted from blower 12, to diffuse air from the guides 24. The lower baffles 28 are disposed at an angle of about 10° to the airflow plane to redirect the flow of air below the base plate 14.

[0030] The plan view of Figure 3 is symmetric about both an axis which traverses the centre of the indents and the centre of the fan and an axis which runs through the centre of the fan and the centre of baffles 26 and 28. This symmetric arrangement allows a fan to be accommodated which can rotate in either direction.

[0031] Figures 4 and 5 shows results from the fan unit. Figure 5 shows a plot of the average air velocity taken at 15 different points in the fan unit. The 15 locations within the fan unit are shown in Figure 4.

[0032] It can be seen that far superior results arc provided when the air guide and baffle are present. Thus, the present invention allows a higher air velocity which provides enhanced air circling action with the same amount of driving power to the fan. Hence, the present invention provides considerable energy advantages to that of the prior art.

[0033] Figure 5 also shows the noise level measured I metre away from the fan in decibels for a fan filter unit with the air guide and baffle and without the air guide and baffle. It can be seen that the noise is greatly reduced for the case where the air guide and baffle are present.


Claims

1. A fan unit comprising:

a. a fan blower (12) configured to emit air in a plurality of directions in an air flow plane;

b. a pair of guides (24A, 24B) disposed on opposite sides of said fan blower (12) in the said air flow plane to guide the flow of air between the two guides (24A, 24B) each guide (24A, 24B) having an indent (25A, 25B) opposite said fan (12) to accommodate said fan (12);

c. each guide (24A, 24B) being symmetric about a symmetry plane perpendicular to the air flow plane formed through the centre of the fan (12) and at least one of the indents (25A, 25B);

d. baffles (26A, 26B, 28A, 28B) at each end of the guides (24A, 24B) to direct air out of the unit, the baffles (26A, 26B, 28A, 28B), characterised in that the baffles (26A, 26B, 28A, 28B) are inclined with respect to the airflow plane, and each guide (24A, 24B) is formed such that there is a protrusion (27A, 27B), on either side of the indent (25A, 25B), on each guide (24A, 24B), each protrusion (27A, 27B), extending towards the opposite guide (24A, 24B), so that each guide (24A, 24B) has a shape substantially similar to a "W".


 
2. A fan unit as claimed in claim 1, wherein the baffles comprise upper baffles (26A, 26B, 28A, 28B) and lower baffles at each end of the guides (25A, 25B), the lower baffles (28A, 28B) being below the upper baffles (26A, 26B) with reference to a direction perpendicular to the air flow plane, the lower baffles (28A, 28B) being inclined such that the distance between the upper and lower baffles decreases in a direction away from the fan (12).
 
3. A fan unit according to claim 1, wherein the guides (24A, 24B) have a smoothly varying profile at the protrusions (27A, 27B).
 
4. A fan unit according to any preceding claim, wherein the guides (24A, 24B), have a smoothly varying profile at the indents (25A, 25B).
 
5. A fan unit according to any preceding claim, wherein the guides (24A, 24B), are arranged symmetrically with respect to one another on either side of the fan (12).
 
6. A fan unit according to any preceding claim wherein the guides (24A, 24B) comprise a solid material.
 
7. A fan unit according to any proceeding claim, wherein the baffles (26A, 26B, 28A, 28B) comprise a perforated material.
 
8. A fan unit according to claim 2, wherein said upper baffles (26A, 26B) are disposed at an angle of from 40 degrees to 60 degrees to the plane of air flow.
 
9. A fan unit according to claim 9, wherein said upper baffles (26A, 26B) are disposed at an angle of 45 degrees to the plane of air flow.
 
10. A fan unit according to claim 2, wherein the lower baffles (28A, 28B) are disposed at an angle in the range of from 5 degrees to 15 degrees to the plane of air flow.
 
11. A fan unit according to claim 10, wherein the lower baffles (28A, 28B) are disposed at an angle of 10 degrees to the plane of air flow.
 
12. A fan unit according to any one of the preceding claims, wherein the fan (12) and guides (24A, 24B) are disposed on a base plate (14).
 
13. A fan unit according to claim 12, wherein the unit further comprises a top housing (16) coupled to said base plate (14) with an inlet (18) for drawing air into the fan (12) and side sections for enclosing the fan (12), an air outlet (19) being formed by a gap between the base plate (14) and the side sections.
 
14. A fan unit according to claim 13, wherein the lower baffles (28A, 28B) are at least partially located in the gap between the side sections and the base plate (14).
 
15. A fan unit according to any one of the preceding claim, comprising a filter (32).
 
16. A fan unit as claimed in claim 1, wherein the pair of guides (24A, 24B) enable the fan blower (12) to rotate either clockwise or anticlockwise.
 


Revendications

1. Unité de ventilateur, comprenant:

a. un souffleur de ventilateur (12) destiné à émettre de l'air dans plusieurs directions dans un plan d'écoulement de l'air;

b. une paire de guides (24A, 24B) agencée sur les côtés opposés dudit souffleur du ventilateur (12) dans ledit plan d'écoulement de l'air pour guider l'écoulement d'air entre les deux guides (24A, 24B), chaque guide (24A, 24B) comportant une entaille (25A, 25B) opposée audit ventilateur (12) pour recevoir ledit ventilateur (12);

c. chaque guide (24A, 24B) étant symétrique à un plan de symétrie perpendiculaire au plan d'écoulement de l'air formé à travers le centre du ventilateur (12) et au moins une des entailles (25A, 25B);

d. des chicanes (26A, 26B, 28A, 28B) au niveau de chaque extrémité des guides (24A, 24B) pour diriger l'air hors de l'unité, caractérisée en ce que les chicanes (26A, 26B, 28A, 28B) sont inclinées par rapport au plan d'écoulement de l'air, chaque guide (24A, 24B) étant formé de sorte qu'une protubérance (27A, 27B) soit formée de chaque côté de l'entaille (25A, 25B) sur chaque guide (24A, 24B), chaque protubérance (27A, 27B) s'étendant en direction du guide opposé (24A, 24B) de sorte que chaque guide (24A, 24B) ait pratiquement une forme en « W ».


 
2. Unité de ventilateur selon la revendication 1, dans laquelle les chicanes comprennent des chicanes supérieures (26A, 26B, 28A, 28B) et des chicanes inférieures au niveau de chaque extrémité des guides (25A, 25B), les chicanes inférieures (28A, 28B) étant agencées au-dessous des chicanes supérieures (26A, 26B) par rapport à une direction perpendiculaire, au plan d'écoulement de l'air, les chicanes inférieures (28A, 28B) étant inclinées de sorte que la distance entre les chicanes supérieures et inférieures est réduite dans une direction allant à l'écart du ventilateur.
 
3. Unité de ventilateur selon la revendication 1, dans laquelle les guides (24A, 24B) ont un profil à variation régulière au niveau des protubérances (27A, 27B).
 
4. Unité de ventilateur selon l'une quelconque des revendications précédentes, dans laquelle les guides (24A, 24B) ont un profil à variation régulière au niveau des entailles (25A, 25B).
 
5. Unité de ventilateur selon l'une quelconque des revendications précédentes, dans laquelle les guides (24A, 24B) sont agencés de manière symétrique l'un par rapport à l'autre de chaque côté du ventilateur (12).
 
6. Unité de ventilateur selon l'une quelconque des revendications précédentes, dans laquelle les guides (24A, 24B) sont composés d'un matériau solide.
 
7. Unité de ventilateur selon l'une quelconque des revendications précédentes, dans laquelle les chicanes (26A, 26B, 28A, 28B) sont composées d'un matériau perforé.
 
8. Unité de ventilateur selon la revendication 2, dans laquelle lesdites chicanes supérieures (26A, 26B) sont agencées à un angle compris entre 40 degrés et 60 degrés par rapport au plan d'écoulement de l'air.
 
9. Unité de ventilateur selon la revendication 8, dans laquelle lesdites chicanes supérieures (26A, 26B) sont agencées à un angle de 45 degrés par rapport au plan d'écoulement de l'air.
 
10. Unité de ventilateur selon la revendication 2, dans laquelle les chicanes inférieures (28A, 28B) sont agencées à un angle compris entre 5 degrés et 15 degrés par rapport au plan d'écoulement de l'air.
 
11. Unité de ventilateur selon la revendication 10, dans laquelle les chicanes inférieures (28A, 28B) sont agencées à un angle de 10, degrés par rapport au plan d'écoulement de l'air.
 
12. Unité de ventilateur selon l'une quelconque des revendications précédentes, dans laquelle le ventilateur (12) et les guides (24A, 24B) sont agencés sur une plaque de base (14).
 
13. Unité de ventilateur selon la revendication 12, dans laquelle l'unité comprend en outre un boîtier supérieur (16) couplé à ladite plaque de base (14), avec une entrée (18) pour aspirer l'air dans le ventilateur (12), et des sections latérales pour renfermer le ventilateur (12), une sortie d'air (19) étant formée par un espace entre la plaque de base (14) et les sections latérales.
 
14. Unité de ventilateur selon la revendication 13, dans laquelle les chicanes inférieures (28A, 28B) sont au moins partiellement agencées dans l'espace entre les sections latérales et la plaque de base (14).
 
15. Unité de ventilateur selon l'une quelconque des revendications précédentes, comprenant un filtre (32).
 
16. Unité de ventilateur selon la revendication 1, dans laquelle la paire de guides (24A, 24B) permet la rotation du souffleur du ventilateur (12) dans le sens des aiguilles d'une montre et dans le sens contraire des aiguilles d'une montre.
 


Ansprüche

1. Gebläse-Einheit, die aufweist:

a. ein Ventilatorgebläse (12), das ausgebildet ist, um Luft in einer Vielzahl von Richtungen in einer Luftströmungsebene auszustoßen;

b. ein Paar Führungen (24A, 24B), die an entgegengesetzten Seiten des Ventilatorgebläses (12) in der Luftströmungsebene angeordnet sind, um den Luftstrom zwischen den zwei Führungen (24A, 24B) zu führen, wobei jede Führung (24A, 24B) eine Vertiefung (25A, 25B) entgegengesetzt dem Gebläse (12) aufweist, um das Gebläse (12) aufzunehmen;

c. wobei jede Führung (24A, 24B) symmetrisch um eine Symmetrieebene senkrecht zur Luftströmungsebene ist, die durch die Mitte des Gebläses (12) und mindestens eine der Vertiefungen (25A, 25B) gebildet wird;

d. Prallwände (26A, 26B, 28A, 28B) an jedem Ende der Führungen (24A, 24B), um Luft aus der Anlage zu lenken, wobei die Prallwände (26A, 26B, 28A, 28B) dadurch gekennzeichnet sind, dass die Prallwände (26A, 26B, 28A, 28B) mit Bezugnahme auf die Luftströmungsebene geneigt sind, und jede Führung (24A, 24B) so ausgebildet ist, dass ein Vorsprung (27A, 27B) auf beiden Seiten der Vertiefung (25A, 25B) bei jeder Führung (24A, 24B) vorhanden ist, wobei sich jeder Vorsprung (27A, 27B) in Richtung der entgegengesetzten Führung (24A, 24B) erstreckt, so dass jede Führung (24A, 24B) eine Form aufweist, die im Wesentlichen gleich einem "W" ist.


 
2. Gebläse-Einheit nach Anspruch 1, bei der die Prallwände obere Prallwände und untere Prallwände (26A, 26B, 28A, 28B) an jedem Ende der Führungen (25A, 25B) aufweisen, wobei die unteren Prallwände (28A, 28B) unterhalb der oberen Prallwände (26A, 26B) mit Bezugnahme auf eine Richtung senkrecht zur Luftströmungsebene sind, wobei die unteren Prallwände (28A, 28B) so geneigt sind, dass der Abstand zwischen den oberen und unteren Prallwänden in einer Richtung weg vom Gebläse (12) kleiner wird.
 
3. Gebläse-Einheit nach Anspruch 1, bei der die Führungen (24A, 24B) ein sich gleichmäßig veränderndes Profil an den Vorsprüngen (27A, 27B) aufweisen.
 
4. Gebläse-Einheit nach einem der vorhergehenden Ansprüche, bei der die Führungen (24A, 24B) ein sich gleichmäßig veränderndes Profil an den Vertiefungen (25A, 25B) aufweisen.
 
5. Gebläse-Einheit nach einem der vorhergehenden Ansprüche, bei der die Führungen (24A, 24B) symmetrisch mit Bezugnahme zueinander auf beiden Seiten des Gebläses (12) angeordnet sind.
 
6. Gebläse-Einheit nach einem der vorhergehenden Ansprüche, bei der die Führungen (24A, 24B) ein Vollmaterial aufweisen.
 
7. Gebläse-Einheit nach einem der vorhergehenden Ansprüche, bei der die Prallwände (26A, 26B, 28A, 28B) ein perforiertes Material aufweisen.
 
8. Gebläse-Einheit nach Anspruch 2, bei der die oberen Prallwände (26A, 26B) unter einem Winkel von 40 Grad bis 60 Grad zur Ebene der Luftströmung angeordnet sind.
 
9. Gebläse-Einheit nach Anspruch 8, bei der die oberen Prallwände (26A, 26B) unter einem Winkel von 45 Grad zur Ebene der Luftströmung angeordnet sind.
 
10. Gebläse-Einheit nach Anspruch 2, bei der die unteren Prallwände (28A, 28B) unter einem Winkel im Bereich von 5 Grad bis 15 Grad zur Ebene der Luftströmung angeordnet sind.
 
11. Gebläse-Einheit nach Anspruch 10, bei der die unteren Prallwände (28A, 28B) unter einem Winkel von 10 Grad zur Ebene der Luftströmung angeordnet sind.
 
12. Gebläse-Einheit nach einem der vorhergehenden Ansprüche, bei der das Gebläse (12) und die Führungen (24A, 24B) auf einer Grundplatte (14) angeordnet sind.
 
13. Gebläse-Einheit nach Anspruch 12, bei der die Anlage außerdem ein oberes Gehäuse (16), das mit der Grundplatte (14) gekoppelt ist, mit einem Eintritt (18) für das Ansaugen von Luft in das Gebläse (12) und Seitenabschnitte für das Einschließen des Gebläses (12) aufweist, wobei ein Luftaustritt (19) durch einen Spalt zwischen der Grundplatte (14) und den Seitenabschnitten gebildet wird.
 
14. Gebläse-Einheit nach Anspruch 13, bei der die unteren Prallwände (28A, 28B) mindestens teilweise in dem Spalt zwischen den Seitenabschnitten und der Grundplatte (14) angeordnet sind.
 
15. Gebläse-Einheit nach einem der vorhergehenden Ansprüche, das einen Filter (32) aufweist.
 
16. Gebläse-Einheit nach Anspruch 1, bei der das Paar Führungen (24A, 24B) ermöglicht, dass sich das Ventilatorgebläse (12) entweder im Uhrzeigersinn oder im Gegenuhrzeigersinn dreht.
 




Drawing