AU674976B2

AU674976B2 - Fan air deflector

Info

Publication number: AU674976B2
Application number: AU70358/94A
Authority: AU
Inventors: Peter Sydney Wright
Original assignee: FF Seeley Nominees Pty Ltd
Current assignee: FF Seeley Nominees Pty Ltd
Priority date: 1993-08-20
Filing date: 1994-08-19
Publication date: 1997-01-16
Anticipated expiration: 2014-08-19
Also published as: AU7035894A

Description

Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

r Name of Applicant: Actual Inventor: Address for Service: F F SEELEY NOMINEES PTY LTD PETER SYDNEY WRIGHT KEN MADDERN PATENT ATTORNEY, Floor, 150 Grenfell Street, Adelaide, South Australia, 5000 Invention Title: "FAN AIR DEFLECTOR" Details of Associated Provisional Application No: PM 0753 dated 20th August 1993 The following statement is a full description of this invention, including the best method of performing it known to the applicant.

This invention relates to a fan air deflector of the type which may be used for example in an evaporative cooler which has four vertical side walls comprising evaporative pads, and a central shroud surrounding a fan, the shroud and fan assembly being contained within the space defined by the four side walls.

There are several problems which are encountered with the relatively large evaporative coolers which are sometimes mounted externally on buildings, the first being that the air flow requirements place dimensional limitations in the vertical direction which are sometimes most inconvenient, especially when a low profile is required, the second being that there can be uneven air flow into the fan blades at the mouthi of the deflector due to the increased space between the duct and the pads at the localities of the pad corners, and the third being that as a fan blade passes air straightener blades, there tends to be a pneumatic impact which results in excessive noise development.

With the object of overcoming at least some of these difficulties, an fan air deflector having a central axis, which, when vertical, extends centrally through a hollow rectangular base, a mouth, a wall joining said base and mouth having a circular intermediate wall portion located between said base and S 20 mouth, the base, mouth and wall portion all being symmetrical about said axis, said mouth being defined by an upwardly and outwardly curved flange which curves radially outwardly from said intermediate wall portion by a greater distance in diagonal planes of said base than between those planes. Thus when the deflector is located within an evaporative cooler which has four cooler pads extending upwardly, but spaced outwardly from the mouth, and the deflector is parallel to the cooler base, there is a more even flow of air into the mouth from the cooler pads. Traditionally the motor is mounted below the o cylindrical shroud and generally above the air straighteners which are usually carried independently on arms secured at their outer ends to a base.

30 In order to reduce the noise and also improve efficiency, there are provided air straighteners in an embodiment of this invention which have at least a tangential component of direction, so that the upstream edge of each air straightener is progressively traversed by each blade of a fan.

While the invention need not necessarily include the above mentioned details, an embodiment is described hereunder in some detail with reference to and is illustrated in the accompanying drawings, in which: Fig 1 is a top view of the air deflector; Fig 2 is an underside view; Fig 3 is a top perspective; p p *'00 e* Fig 4 is an underside perspective; Fig 5 is a section taken on line 5-5 of Fig 1; Fig 6 is a section taken on line 6-6 of Fig 1; and Fig 7 is a diagrammatic central section through an evaporative air cooler.

In this embodiment, an air deflector 10 has a central axis A-A (Fig 6), and comprises a square base 11 which is arranged to lie between the four pads which constitute the evaporative side walls of an evaporative cooler, the walls normally being spaced outwardly from the base 11. The base 11 has two diagonal planes D-D which intersect in axis A-A.

The base 11 is surmounted by short shroud 12 which has an intermediate cylindrical wall portion arranged to surround fan blades of a fan which is carried on the shaft of a motor, itself supported from the base 11. The fan and motor are shown only in Fig 7 and are in accordance with well known art.

The mouth 13 of the duct 12 is surrounded by an outwardly and downwardly curved flange 14, flange 14 being relatively narrow at the locations above the sides of the base 11, and relatively broad at the locations 16 above the corners of the base 11. In the embodiment shown the outwardly and downwardly curved shape is defined by circular arcs for the entire length of the flange 14, and the centres of curvature lie within a flat horizontal plane P-P (Fig l* This has the effect of providing an upward bulge at each of the locations 16, as best seen in Fig 6, and between the corner bulges 16 the flange 14 at its locations 15 does not extend either upwardly or radially outwardly to quite the 25 same degree, as also can be seen from Figs 5 6. This has an important effect in that the distribution of incoming air into the duct 12 is more evenly arranged, since the peripheral edge of flange 14 is spaced from the evaporative pad (not shown) by a more nearly constant distance, and this inturn reduces the tendency for incoming air to be turbulent, contributing to an improvement in efficiency and also an improvement in reduction of noise development.

S.As said above, one of difficulties is the development of noise occurs as fan blades pass over the air straightening deflectors which are normally radial deflectors and are traversed by the fan blades for very short periods of time, 35 causing impulses which will develop noise. To reduce noise it is necessary to have a wide spacing between the upper edges of the straightening deflectors and the fan blades, and this imparts dimensional restraints, which are inconvenient in many instances.

However in this embodiment the air straightening deflectors 19 have a tangential component of direction, and are unitary with the remainder of the air deflector 10. As in prior art, they are carried on, or constitute, motor mounting arms 20 which terminate at their outer ends in base 11, and at their inner ends in a motor mounting ring 21 which surrounds and supports the fan motor. They are curved in cross sectional shapes as seen in Figs 5 6, and extend tangentially outwardly from each side of the motor when the motor is supported from the base 11 of the air deflector 10 In this way the time taken for a fan blade to traverse an upper edge of an air deflector 19 is very much increased, thereby reducing the development of noise producing impulses. Owing to this advantage, it is possible to have the spacing between the deflectors and fan blades reduced (that is the upper edges of the deflectors closer to the fan blades), and further the deflectors can have smooth cross sectional shapes which reduce the development of turbulence, again contributing to an improvement in efficiency as well as the improvement in noise reduction.

Desirably the entire air deflector 10 is a unitary moulding, but it can constitute a subassembly of components which are arranged in the configuration similar to that shown in the drawings.

Fig 7 illustrates how the air deflector 10 is utilised in an evaporative cooler 25 which has four vertical sides 26 each comprising evaporative pads.

The motor 27 of a fan and motor assembly 28 is mounted on the motor mounting ring 21, the fan blades 29 co-operating with the intermediate 25 cylindrical wall portion of shroud 12 for high efficiency impulsion of air, and air flow is streamlined by the curved flange 14.

As can be seen by comparing Figs 1, 5 and 6, flange 14 extends radially outwardly from axis A-A further at the corner than between the side walls of base 11. Thus there is less resistance to air flow over the flange 14, where it is closest to sides 26 than if the flange were of constant cross-sectional shape, and at the corners where there is usually more space, the larger radius of curvature also offers less air flow resistance. Air flow restriction is therefore less than with a generally circular flange.

Claims

1. A fan air deflector having a central axis, which, when vertical, extends centrally through a hollow rectangular base, a mouth, a wall joining said base and mouth having a circular intermediate wall portion located between said base and mouth, the base, mouth and wall portion all being symmetrical about said axis, said mouth being defined by an upwardly and outwardly curved flange which curves radially outwardly from said intermediate wall portion by a greater distance in diagonal planes of said base than between those planes.

2. A fan air deflector according to claim 1 wherein the radially outermost part of said curved flange incorporates a return portion.

3. A fan air deflector according to any preceding claim wherein said rectangular base is square.

4. A fan air deflector according to any preceding claim wherein the curvature of said flange is substantially arcuate in all cross- sections which includes said axis, and centres of curvature lie in one plane which is normal to said central axis. A fan air deflector according to any preceding claim further comprising a motor mounting ring co-axial with said central axis, and air 20 straightening deflectors joining the motor mounting ring to said base. S6. A fan air aeflector according to claim 5 wherein said air straightening deflectors are curved in cross-sectional shape.

7. A fan air deflector according to claim 5 or claim 6 wherein said air straightening deflectors each have a non-radial component of direction. S 25 8. Improvements in an evaporative cooler having four vertical sides comprising evaporative pads, and a fan and motor assembly within space surrounded by said four vertical sides, said improvements comprising an air deflector according to any one of claims 1 to 7, and mounting means on the air deflector mounting said fan and 30 motor assembly. o. A fan air deflector substantially as hereinbefore described with referenc3 to and as illustrated in the accompanying representations. °i i 1 I An evaporative cooler substantially as hereinbefore described with reference to and as illustrated in the accompanying representations, Dated this 21 st day of August, 1996. F F SEELEY NOMINEES PTY LTD By its Patent Attorney KEN MADDERN A6 4 f ABSTRACT A fan air deflector (10) has a square base an intermediate cylindrical wall portion which surrounds fan blades (29) of a fan and motor assembly and a mouth at its upper end, the mouth (13) being surrounded by an upwardly and outwardly curved flange (14) which extends upwardly and outwardly at (16) more in diagonal planes of the four corners of the base (11) than between them. a**o oe P