CA2857972A1 - An air diffuser and an air circulation system - Google Patents

Abstract

An air diffuser comprises a plurality of discharge elements (4a to 4d). The discharge elements are configured such that they are able to be arranged in the diffuser so as to abut to form a tessellation of discharge elements in a plane. At least one of the discharge elements may be displaceable out of the plane for adjustment of its orientation.

Description

Received 19/06/2013 AN AIR DIFFUSER AND AN AIR CIRCULATION SYSTEM
Technical Field An air diffuser and an air circulation system including the air diffuser are disclosed.
Background Art Many buildings with large volume spaces contain air delivery systems in which the air is delivered to and mixed into the occupancy space via one or more side blow diffusers, which may be located in a sidewall or bulkhead.
Such systems can deliver supply air through grilles, each of which delivers the supply air largely as a single jet of air into the space. Discharge direction adjustahility of the jet of air is via horizontal and/or vertical vanes that may be manually. swivelled about vertical ancVor horizontal axes. Hence, the discharge direction may be manually . adjusted in up to two planes¨tip and down, and left and right¨and horizontal throw may be increased or decreased by arranging vane direction to converge or diverge, thereby concentrating or dispersing the discharged airflow pattern, respectively.
In order for an isothermal air stream to achieve a given axial throw at a fixed terminal velocity, the requisite velocity of the air stream, as it is discharged axially from a grille, Is largely inversely proportional to the volume flow rate of the discharged air stream. Consequently, in order to achieve a given throw from a grille, the effective discharge diameter of the grille needs to be increased largely in proportion to the increase in volume flow rate to realise the requisite inverse discharge velocity relationship. This results in an increased grille opening discharge size (and hence a "thicker" supply air stream) and in reduced discharge velocity (causing a more "limp"
supply air stream), the larger the airflow rate to be discharged from the grille.
These factors can, in turn, reduce the stability of the discharged air stream (such as by increasing uncontrolled air stream trajectory deviations in non-isothermal AMENDED SHEET
IPEA/All Received 19/06/2013 applications, or due to air motion from other sources in the space). These factors can also increase temperature and velocity deviations from the average in the space (such as a tendency towards hot and stuffy, and cold and draughty spots). In other words, the suitability of side blow grilles to spaces requiring uniform temperature and velocity distribution decreases, the greater Is the volume flow rata to be discharged by each especially if draught-free comfort is required. To overcome this limitation, when each side blow grille is to discharge a large volume flow rate of air, or when high levels of comfort are required, high induction side blow diffusers, such as multi-nozzle diffusers, can be used as an alternative to grilles. This is because multi-nozzle diffusers induce large quantities of room air into the supply air stream. This can bring about rapid discharge velocity decay, thereby allowing relatively high discharge velocities to be used that stabilise the discharged air stream, whilst reducing draught-risk through rapid air stream deceleration.
Additionally, multi-nozzle diffusers can break down the temperature differential between supply and room air, thereby reducing air stream trajectory deviation in non-isothermal applications to further stabilise the air stream trajectory, whilst simultaneously minimising temperature deviations in the space. Such highly inductive discharge, even of large airflow rates, can produce MOM stable horizontal throws with low terminal velocities, whilst rapidly equalising supply air stream temperature with room air temperature, achieving more uniform temperature and velocity distribution and less draught risk than would generally be possible if the same airflow rate were To be discharged from a grille of similar throw.
High induction multi-nozzle diflbsers can supply air streams to a space that largely have high mass flow rates (primary air plus large quantities of induced secondary air) travelling at low velocities (duo to rapid discharge velocity decay brought about by high induction). These air streams can be suitable both for throws that are relatively short, as the low velocity air-streams prevent draughts, and relatively long, as the high momentum of the high mass flow rate air streams ensures relatively high maximum throw. This is in contrast to air streams from grilles, which have a relatively narrow allowable throw band for each alzflow rate and diffuser vane setting, thereby AMENDED SHEET

Received 19/06/2013 further compromising comfort, as well as increasing HVAC conunissioning costs and occupant complaints.
The high induction characteristics of multi-nozzle diffusers can also improve system heating performance, by virtue of strongly diluting the warm supply air with large quantities of cooler room air, thereby reducing the degree of buoyant supply air stream stratification to a high level.
The discharge direction of prior art multi-nozzle diffusers may be manually adjustable, such as by swivelling the individual nozzles in a ball-in-socket arrangement, or by integrating nozzles with a fixed incline into rotatable discs that are parallel to and that protrude from or are recessed into the diffuser discharge face. in prior art multi-nozzle diffusers, the diffuser discharge face of ball-In-socket and rotatable disc designs is neither flush nor uniform in discharge pattern. This often leads to such multi-nozzle diffusers being rejected due to unsightliness.
Further, as the discharge nozzles are usually made of plastic, colour choice tends to be limited, especially where small quantities of difflisers arc involved, which is in contrast to the large range of colours usually available for grilles (e.g.
when made from powder coated metal vanes), The vanes of grilles can suffer from dirt deposits, called "smudging", that settle onto the visible grille surfaces, including the recessed surfaces of the vanes. Not only is 2 o this unsightly, but these surfaces are also difficult to clean, and cleaning generally results in the inadvertent re-adjustment of vanes, thereby compromising airflow to the space, hence causing discomfort and poor performance.
Similarly, wiping clean prior art multi-nozzle diffusers can result in inadvertent discharge direction adjustment due to the vulnerability of the protruding nozzles or nozzle discs to accidental re-adjustment.
Grilles may also suffer from condensation when used in high humidity environments, such as lobbies in. the tropics, or in restaurants. The high induction of multi-nozzle diffusers can reduce the condensation risk, by ensuring strong air motion AMENDED SHEET
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Received 19/06/2013 at the diffuser face, thereby raising the diffuser face temperature, and also by raising the supply air stream temperature through dilution with warmer room air.
A reference to prior rut herein is not to be taken as an admission that the prior art is common general knowledge of a person of ordinary skill in the art Summary of the Disclosure Disclosed herein is a high induction air diffuser assembly. The air diffusor assembly can find use in combination with a sidewall, bulkhead, window sill, parapet, floor or ceiling air delivery system.
The air diffuser comprises a plurality of discharge elements. The discharge elements arc configured such that they are able to be arranged in the diftbser to form a tessellation of discharge elements in a plane. The discharge elements ere also able to be adjusted into a new orientation in the tessellation plane. This configuration enables a number of possible orientations of at least one of the discharge elements to be achieved, as will become apparent hereafter.
The perimeters of the discharge elements may largely abut to largely form a single plane tessellation of the discharge elements.
In an embodiment, at least one discharge element may discharge a primary air stream largely inclined to the perpendicular axis of the tessellation plane.
In an embodiment, the primary air stream may be discharged by at least one discharge canal integrated into the at least one discharge element.
In an embodiment, the at least one discharge canal may be inclined substantially to an axis that extends perpendicularly of the tessellation plane of discharge elements, The discharge direction of the primary air stream may largely be 2S determined by the discharge canal orientation (e.g. angle of inclination of its central axis).
AMENDED SHEET
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Received 19/06/2013 In an embodiment, the perimeter of at least one discharge element, when viewed in the tessellation plan; may substantially take the form of a polygon.
In an embodiment, the polygon may be mathematically regular (e.g. the sides and angles of the polygon are all equivalent).

5 In an embodiment, the perimeters of the discharge elements may largely form an Archirnedean tessellation (e.g, the perimeters of the discharge elements may largely have disposed thereat a variety of regular polygons, the arrangements of which can be identical at every vertex).
In an embodiment, the perimeters of the discharge elements may largely form a 1.0 regular tessellation (e.g. the perimeters of the discharge elements may largely fomi congruent regular polygons, in which "congruent" can indicate that the polygons are all the same size and shape).
In an embodiment, the at least one discharge element with the at least one discharge canal may be engaged into the tessellation of discharge elements in any one 3.5 of at least two unique orientations when rotated about an axis perpendicular to the tessellation plane.
In an embodiment, the number of sides, which the discharge element has, that largely abut other discharge elements can correspond to (equal) or be a multiple of the number of unique orientations, about the perpendicular axis.
20 In an embodiment, the orientation, about the perpendicular axis, of at least one of the primary discharge elements may be manipulable to vary the airflow direction of the primary air stream.
In an embodiment, the primary air stream may be discharged through at least one of a plurality of discharge perforations located in a discharge plate of the diffusor, 25 The discharge plate may generally lie in a plane that Ls parallel to the tessellation plane of discharge elements.
In an embodiment, the downstream discharge edge of the at least one discharge AMENDED SHEET
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Received 19/06/2013 canal largely may abut or closely face the discharge plate (i.e. at its inside face), In an embodiment, the centre points of the discharge perforations may largely be coincident with the vertices of a largely Archimedean tessellation (i.e. a tessellation formed largely of a variety of regular polygons, the arrangements of which are identical 5 at every vertex).
In an embodiment, the centre points of the discharge perforations may largely be coincident with the vertices of a largely regular tessellation (i.e. a tessellation comprising largely congruent regular polygons, in which "congruent" means that the polygons are all the same size and shape).
In an embodiment, the number of sides that at lout one discharge element has, which largely abut other discharge elements, may be a multiple of the number of unique orientations, about the perpendicular axis, in which the centre points of all discharge canal discharge openings of that discharge element may largely be coincident with the, centre points of discharge perforations.
In an embodiment, the number of sides, which at least one discharge element has, which largely abut other discharge elements, may be equal to the number of unique orientations, about the perpendicular axis, in which the centre points of all discharge canal discharge openings of that discharge element are largely coincident with the centre points of discharge perforations.
In an embodiment, the centre point of at least one discharge canal discharge opening may largely be coincident with the centre point of a discharge perforation (though not necessarily the seine discharge perforation) for at teak that number of unique orientations of the discharge clement, about the perpendicular axis, in which the discharge element may be engaged into the tessellation of discharge elements.
In an embodimen.t, the discharge edge of at least onc discharge canal may either be largely coincident with, or may largely be contained within the perimeter of one of the discharge perforations.
In an embodiment, the diffhser may discharge at least one secondary air stream AMENDED SHEET

Received 19/06/2013 In close proximity to a primary air stream.
In an embodiment, the secondary air stream may be of substantially lower momentum than the primary air stream to which it is in close proximity.
In an embodiment, the secondary air stream may be Induced by the primary air stream to which it is in close proximity to form one combined air stream.
In an embodiment, the discharge direction of the combined air stream may largely be determined by the discharge direction of the primary air stream to which the secondary air stream is in close proximity. In an embodiment, the throw of the combined air stream may largely be determined by the throw of the primary air stream to which the secondary air stream is in close proximity. For example, the discharge direction and throw of the combined air stream may largely be determined by the discharge direction and throw of the primary air stream to which the secondary air stream is in close proximity.
In an embodiment, the secondary air stream may be discharged by at least one opening integrated into at least one discharge element.
In an embodiment, the secondary air stream may be discharged by at least one opening between largely abutting discharge elements.
In an embodiment, the secondary air stream may be discharged through at least one of the discharge perforations.
In an embodiment, an Inlet plate may be located upstream of the tessellation of primary air supply discharge elements.
In an embodiment, at least one discharge element may be attached to the inlet plate.
In an embodiment, the inlet plate may be located clear of the tessellation of primary discharge elements.
In an embodiment, the plane of the inlet plate may largely be parallel to the AMENDED SHEET
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Received 19/06/2013 tessellation plane of the discharge elements.
In an embodiment, the inlet plate may largely be perforated.
In an embodiment, at least one biasing mechanism may be provided. This mechanism can communicate with (e.g. bias against) a given discharge element so as to S exert an engaging force directed towards the inlet plate, pushing that discharge element, when engaged in the tessellation of discharge elements, towards e.g. the discharge plate (when present). The biasing mechanism may e.g. take the form of a coil or leaf spring.
In an embodiment, a disengaging force that is greater than the engaging force and that is directed from e.g. the discharge plate towards the inlet plate can disengage that discharge element from the tessellation of discharge elements.
In an embodiment, the disengaging force may be applied to the discharge element via an adjustment tool inserted through a discharge perforation.
In an embodiment, rotation of the adjustment tool about the axis generally perpendicular to the tessellation plane of discharge elements (e.g. whilst maintaining a disengaging force against the discharge element) can rotate the discharge element about the same axis.
In an embodiment, the discharge element may be re-engaged back into the tessellation plane of discharge elements, but now in a new orientation, when the disengaging force is removed.
Also disclosed herein is an air diffUser comprising a plurality of discharge elements. The discharge elements are configured such that they are able to be arranged in a plane. At least one discharge element is able to be displaced from the plane, rotated about an axis that is generally perpendicular to the plane and, once a given rotational position has been reached, re-displaced back into the plane. The discharge elements are able to be adjusted into a new orientation in the plane. This air diffuser may otherwise be configured as set forth above.
Also disclosed herein is a ducting system and/or an air supply system AMENDED SHEET

Received 19/06/2013 incorporating at least one air diffuser as act forth above.
Also disclosed herein is an air diffuser comprising a frame, and a plurality of discharge elements positioned within or adjacent to the frame. Each discharge element abuts against or closely faces at least one other discharge element. The discharge elements have a plan shape of a polygon. The discharge elements are able to be adjusted Into a new orientation in the frame.
At least one of the discharge elements may be configured to discharge an air stream in a direction that is inclined with respect to an axis that extends generally perpendicularly from a downstream face of the discharge element, The air diffuser may be otherwise configured as set forth above.
Brief Description of the Drawings Notwithstanding any other forms which may fall within the scope of the air diffitser as set forth in the Summary, specific embodiments will now be described, by way of example only, with reference to the accompanying drawings in which:
Figures 1-I to are respective diagrams, each illustrating front, rear and side section views of diffuser element embodiments for an air diffuser to provide highly inductive discharge to an occupancy space;
Figures 2-I to as well as sections A-A and B-B, are diagrams illustrating the front, rear and side section views of a diffuser embodiment with a perforated discharge surface and hexagonal discharge elements as well as part-hexagonal discharge elements;
Figure 3 Illustrates mar, side section and front views of a two hexagonal discharge element embodiments, one embodiment with an upstream locating pin and one embodiment with a downstream locating ring, and each embodiment with an Integrated spring;
Figure 4 illustrates diffuser embodiments having discharge elements with a AMENDED SHEET
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Received 19/06/2013 number of different discharge angles, as well as diffbser embodiments with differing diffuser face dimensions achieved by altering the number, combination and arrangement of hexagonal and part-hexagonal discharge elements;
Figure 5 illustrates a front view of adjacent hexagonal discharge element embodiments, each with differing discharge angles;
Figure 6 illustrates front, rear and side section views of a diffuser embodiment with a perforated discharge surface and perforated inlet surface together with an adjustable slide damper;
Figure 7 illustrates front, side and end views of a diffuser embodiment with a 10 perforated discharge surface and a cut-away to reveal rows of hexagonal and part-hexagonal discharge elements, and indicating dimensions of the diffuser that can be varied;
Figure 8 illustrates a perspective view of a diffuser embodiment together with an Allan key in a number of positions, to illustrate how a user can adjust a given discharge element in use;
Figures 9A and 913 schematically Illustrate, each in a perspective view, the airflow patterns that may be achieved when different discharge elements have each been arranged in a number of differing positions, to thereby illustrate airflows into an occupancy space.
Detailed Description of Specific Embodiments General Diffuser Overview High induction sidewall diffusers are used to better mix a supply of air into a given space (e.g. a room). High induction diffusers can break up the supply air inrcem into a multitude of highly inductive air streams, each one of which strongly mixes and dilutes the supply air with large quantities of room air. This can cause rapid temperature equalisation of each supply air stream with that of the room air, along with intense AMENDED SHEET
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Received 19/06/2013 discharge velocity decay. The resultant low velocity air motion in the space can provide Largely draught-free and generally uniform temperature distribution, as each supply air stream is not only of almost equal temperature to the room air, but is also largely equal in density, preventing air "dumping".
Issues with air "under-throw" and "over-throw" may also be more easily overcome, as the air streams are low in velocity and are Largely at room air temperature, preventing draughts if nearby obstructions deflect them into the occupancy space, whilst their high mass flow rate, due to the large quantities of entrained room air, provides them with sufficient momentum, despite their low velocity, to travel over long distances. Hence, stable, draught-free operation with uniform temperature distribution and a high level of comfort can be achieved, regardless of changes in air supply fan speed or fluctuations in supply air temperature, even when used to deliver air from a low temperature supply air system. However, high induction sidewall diffusers of the prior art are expensive, tend to be aesthetically unappealing and, at the same operating pressure, discharge substantially less air than their low induction counterparts of a similar face size. These shortcomings have largely curtailed their widespread use.
The present disclosure rotates generally to an air diffuser assembly for placement in a wall, bulkhead, duct or window sill penetration. The assembly comprises an optional rectangular mounting frame to be secured in the penetration. The mounting frame may be thermally decoupled from other difltser components. A
perforated discharge plate forms the visible face of the diffuser. This plate may comprise a powder-coated metal for aesthetic and structural benefits.
Upstream of the discharge plate, regular and/or irregular polygonal discharge elements can be employed, which can be arranged in a tessellated pattern and in a planar configuration. For example, generally hexagonal or generally square discharge elements can be employed.
The discharge elements can be arranged in the diffuser to abut or closely face the discharge plate, and can abut one another in various tessellated patterns, such as regular tessellated patterns, semi-regular or Archimedean tessellated patterns, etc, AMENDED SHEET
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= CA 02857972 2014-06-03 Received 19/06/2013 When, in plan-shape, hexagonal or square discharge elements are employed, a staggered or square array, respectively, can be formed. Part-hexagonal or part-square discharge elements, respectively, can be located along the diffuser perimeter to provide rectangular bounding (perimeter) edges to the array, as well to enable separation of the array from the bounding edges of the discharge plate.
Each discharge element comprises one or, more generally, a plurality of discharge openings, hi one example these can take the form of individual canals which can generally be Arranged in e.g. a honeycomb, square, circular, etc pattern.
The element discharge openings can align with perforations formed in the discharge plate such that, when the discharge element array abuts or closely faces the upstream face of the discharge plate, air directed by the discharge openings passes In that direction straight through the perforations (i.e. its direction is not altered by the perforations/discharge plate). When an axis of each discharge opening is inclined to a perpendicular axis extending front the discharge plate, jets of air can be discharged generally in the direction of incline, The discharge opening angle of inclination can also be selected to differ between sets of the discharge elements.
Discharge element sets with a largest angle of inclination (relative to the perpendicular axis of the discharge plate) may in general be located closest to the diffuser outer edges that are furthest apart whilst those with the smallest angle of inclination (relative to the perpendicular axis of the discharge plate) may in general 'be located closest to the centre of the diffuser. This can help with air flow mixing and induction in the apace to be supplied with air.
Some of the discharge element can have larger (i.e. bore with larger effective diameter) discharge openings, for discharging a "primary" air stream (or an "inducing"
air stream). Discharge openings that are substantially smaller (i.e. bore with smaller effective diameter) can discharge a "secondary" air stream (or a "to-be-induced" or "inducted" air stream).
In a given discharge element, the smaller discharge openings may be less densely spaced than the larger discharge openings. The smaller discharge openings may AMENDED SHEET
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Received 19/06/2013 or may not be Inclined, and may be inclined differently to the larger discharge openings.
The smaller discharge openings may also be formed by notches in the perimeter edges of discharge elements, which can form an opening when discharge elements abut.
The smaller discharge openings may also be located "clear" of the upstream face of the perforated discharge plate, to thereby discharge air into a chamber bounded by the discharge element array, the perforated discharge plate and the diffuser rectangular edge or frame.
Springs can be integrated into the discharge elements which can be compressed and thus push against a perforated inlet plate. This can "lock" the discharge elements into the array, and urge the discharge element perimeters to abut one another in the array. The discharge elements may additionally be guided (e.g. by pins, rings, notches) into respective openings in the discharge plate, to thereby accurately align the discharge openings of each discharge element with perforations in the discharge plate, For example, some discharge elements may be provided with a locating ring formed by protrusions projecting downstream of its edges, the diameter of which is largely equal to the distance between e.g. parallel outer edges of a given regular discharge element.
Some discharge elements may be provided with a locating pin formed by a protrusion projecting upstream and generally centrally from the element.
A screwdriver slot, Hex socket or similar can be formed and located generally centrally in a given discharge element. This slot, socket, etc can align with a discharge face perforation such that a screwdriver head, 1-lax key or similar tool may be inserted by a user located in the space to be supplied with air. The discharge element can be displaced inwardly of the diffuser (i.e. out of its array, and out of its abutment with adjacent discharge element(s)) and, once so displaced, can be rotated via the screwdriver, Hex key or similar tool. When being displaced, thc discharge element can push (compress) against the force of a spring, which otherwise urges it into locking configuration in the array. After the discharge element is rotated (c.g, about a central axis that extends perpendicularly to the discharge face) to a desired new rotational orientation, it is re-engaged into the array, by releasing the force on the screwdriver head, Hex key or similar tool. It may then re-displace (e.g. under the action of the AMENDED SHEET
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= CA 02857972 2014-06-03 = = =

Received 19/06/2013 spring) into one of a number of orientations (e,g, one of six in the case of hexagonal discharge elements, or one of four in the case of square discharge elements, etc). When so re-displaced, the perimeters of the discharge element re-abut and lock with its adjacent discharge elements, to now provide new and unique air discharge directions from its e.g. inclined discharge openings. The Locating pin or ring can also function to retain the discharge element in its array, and can support the element once disengaged, as it is being rotated.
When given discharge elements in the tessellated array have a mathematically regular polygon plan shape, the number of new orientations to which the element can be o rotated can corresponds to or is a fraction of its number of sides, Further, one or more given discharge elements can be configured such that the centre points of all discharge canal discharge openings of that discharge clement may Largely coincide with the centre points of discharge perforations (though not necessarily the same discharge perforation), regardless of the orientation to which the element has been rotated. Further, the discharge edge of at least one discharge canal may either coincide with or be contained within the perimeter of a given one of the discharge perforations.
A perforated slide damper may also be located against the perforated inlet plate. Both the perforated slide damper and the perforated inlet plate may largely be provided with the same perforation pattern and size, with openings of the former able to =
align with those of the perforated inlet plate when, for example, the perforated slide damper is set to open. Sliding the perforated inlet damper such that its holes are out of alignment with those of the perforated inlet plate can then close the perforated slide damper. The perforated slide damper may include out-outs that may be of similar size and shape to the discharge elements and that may be aligned with some of the discharge elements. This can prevent airflow to these select disoharge elements from, for example, being throttled when the slide damper is closed, so as to provide high momentum, highly Inductive and stable supply air discharge from these select discharge elements, even when the slide damper is closed. This can also maintain highly inductive supply air discharge into the space at low airflow rate settings. It can also induce supply air, AMENDED SHEET
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Received 19/06/2013 e.g. that leaks through a. remainder of the slide damper and that is then discharged at low momentum from the dltfliser, to be mixed into the stable, high momentum supply air streams discharged by selected discharge elements. The perforated slide damper may be accessible for adjustment through openings in the discharge elements and via aligned 5 openings in the perforated discharge plate.
Embodipents as Shown in the FigaeI
Reference numerals in the following description and throughout the Figures represent similar or like components or features.
Figure 1 shows three embodiments (Figures 1-I, 1-II and 1-III) of a sidewall 3.0 diffuser in accordance with the teachings herein. The sidewall diffuser is mounted in a wall, duct or bulkhead penetration (1), or similar, and discharges supply air from a duct or pressure plenum (2) into an occupancy space (3).
The sicievvall diffuser comprises a discharge element (4) having a plate-like form and configured for discharging both primary and secondary air streams.
The 15 discharge element (4) has at least one and, in this case, a plurality of discharge canals in the form of inclined discharge openings (5) formed therein. The openings (5) arc angled relative to an axis that extends perpendicularly from a discharge plate (8).
The discharge plate (8) is arranged to abut or closely face the discharge side of the discharge element (4).
The inclined discharge openings (5) are configured to discharge air at a high velocity to create high momentum air jets (6a) ¨ i.e. primary air streams. The high momentum air jets (6a) pass through perforations (7) in the discharge plate (8).
Air also passes from the duct or pressure plenum (2) through smaller openings (9) formed in the discharge element (4) and into a discharge chamber (10) of the discharge element (4) ¨ i.e. secondary air streams. From discharge chamber (10) the air Is discharged at a low velocity and hence as a low momentum airflow (6b) through perforations (11) the discharge plate (8), and thence into the occupancy space (3).
The high momentum air jets (6a) are configured so as to induce room air (12) AMENDED SHEET
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PCT/A1.12012/001474 Received 19/06/2013 as well as to induct the low momentum airflow (6b) discharged through perforations (11) from discharge plenum (10). This induction creates air streams of mixed air that travel away from the diffuser in the general direction of the discharge jets (6a). In the sidewall diffuser embodiments of Figures 1-1 and 1-III, the high velocity air jets (6a) can have an equal angle of discharge relative to one another, whereas in the sidewall diffuser embodiment of Figure 1-II the high velocity air jets (6a) can have unequal angles of discharge relative to one another. Further, in the sidewall diffuser embodiments of Figures 1-I and 1-II, the high velocity air jets (6a) can be well spaced from one another, whereas in the sidewall diffuser embodiment of Figure 1-111 the high velocity air jets (6a) are "bundled" together.
Figure 2 shows another embodiment (le. in Figures 2-1, 241 and 2-111, and in sections A-A and B-B) of a sidewall diffuser in accordance with the teachings herein.
The sections A-A and 13-B in Figure 2 indicate the tessellation plane ((.e. as viewed end-on) in which the discharge elements lie.
Figure 2-1 shows the diffuser discharge face (i.e. with a discharge plate (8) arranged thereat), Figure 2-11 shows the diffuser discharge chamber inlet face, illustrating one example of a tessellation of a number of diffuser elements (such as (4a) to (4d)). Figure 2411 shows various front and side sections of the diffuser, including those taken on the lines A-A and B-B, as well as illustrating adjustment of a given primary air diffuser element (4a).
Again, air passes from the duct or pressure plenum (2), but in this embodiment via e. perforated inlet plate (13) and into a pressure plenum (14) defined thereby. From pressure plenum (14) the air passes to the discharge elements (such as (4a) to (4d)). At least one of the discharge elements (e.g. 4b to 4d) can be attached to the inlet plate (13), However, usually the inlet plate (13) is located so as to be clear of the tessellation of primary air discharge elements (4a), so as not to interfere with their movement/adjustment.
Each discharge element has a generally plate-like profile. Further, each primary air discharge clement (4a) has at least one and, in this case, a plurality of AMENDED SHEET
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Received 19/06/2013 discharge canals in the form of a plurality of inclined discharge openings (5) located therein. In this embodiment, each primary air discharge element has a generally hexagonal form. The inclined discharge openings (5) disoharge air at high speed, as high momentum air jets (6a), and thence through the perforations (7) in the discharge S .. plate (8) ¨ i.e. primary air streams.
Air also passes from pressure plenum (14) through inlet openings (9) formed in the hexagonal (4a) and part-hexagonal discharge elements (4b, 4c and 4d) and into distribution chamber (10) to be discharged at low momentum into the occupancy space (3) via discharge plate perforations (II) ¨ i,e. secondary air streams.
An optional mounting frame (8a) may be attached to the discharge plate (8) which may be folded to form the bounding edges of discharge chamber (10) 30 as to abut the generally hexagonal (4a) and part-hexagonal (4b, 4e and 4d) discharge elements as shown in Figure 2-11, A-A and B.B. The mounting frame (8a) may, as shown in Figure 2-111, also be folded so as to define at least some of the part-hexagonal .. discharge elements (4b, 4c and 4d).
Insulating material (not shown for the sake of clarity) may additionally be sandwiched between mounting frame (8a) and discharge plate (8) to thermally &couple them from one another, thereby reducing the threat of condensation on the mounting frame.
A biasing mechanism in the form of a locking spring (15) may be provided for each of the primary air discharge elements (4a), The locking spring (15) may comprise a coil spring, or may comprise a leaf spring (e.g. that may be integrated with the discharge element, as shown in the embodiment of Figure 3). Each locking spring (15) is located between so as to push against both the perforated inlet plate (13) and the .. upstream face of its respective discharge element (4a). This urges and locks that discharge element (4a) into place in tessellated plane, in a sixty degree staggered array, of the hexagonal discharge elements (4a), whereby at lout two of its hexagonal edges each abut an adjacent respective edge of an adjacent respective hexagonal discharge element (4a). In addition, others of its edges abut one or more of the part-hexagonal AMENDED SHEET
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Received 19/06/2013 discharge elements (4b, 4c and 4d). Similar locking springs (not shown for the sake of clarity) may also be employed to lock the part-hexagonal discharge elements (4b, 4c and 4d) into place.
In accordance with the teachings herein, a force may be applied against the discharge element to further compress the locking spring (15). This force may be applied via a Ilex key, screwdriver or similar tool (16) respectively inserted into a Hex socket, screwdriver slot or similar interface (for example, interface (16a) as shown in Figures 3 and 4, although not shown in Figure 2 for the sake of clarity). The tool may be first inserted through an aligned perforation in the discharge plate (8).
The interface may be generally centrally located in the discharge element (4a) whereby, when it is engaged by the suitable tool, unlocks that discharge element (4a) from the tessellated plane (i.e. unlocks it from Its sixty degree stagger pattern), whereby the discharge element (4a) is moved towards the perforated inlet plate (13).
Having been released from engagement with adjacent discharge elements (i.e. displaced out of the tessellated plane formation), the hexagonal discharge element (4a) is now freed to be rotated by twisting (17) the Ilex key, screwdriver or similar tool (16) into any one of five additional possible orientations. Having selected a given one of those orientations, the Hex key, screwdriver or similar tool (16) can be progressively withdrawn, whereby the retained bias in the compressed locking spring (15) will urge the discharge element (4a) to be displaced back into the tessellated plane, whereby the discharge element relocks with adjacent respective edges of adjacent discharge elements (4a).
Figure 2-1 shows an array of primary air discharge elements (4a) having been positioned whereby those discharge elements (4a) located adjacent to a respective comer have been orientated so that the primary airstream discharges towards that respective corner. Three of the four centrally located discharge elements (4a) have been orientated so that the primary airstream discharges upwardly, whereas the lowermost one of the four centrally located discharge elements discharges downwardly. Of course a whole range of other combinations and permutations are possible.
Figure 3 shows two embodiments of a hexagonal discharge element (4a) in AMENDED SHEET
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Received 19/06/2013 which the locking spring (15) is integrated into the discharge element.
Additionally, the left-side discharge clement embodiment includes a locating pin (18), whereas the right-side discharge element embodiment includes a locating ring (19). Each of the locating pin (18) and locating ring (19) helps to fix its respective discharge element (4a) into the sixty degree staggered array of discharge elements (4a), and may even "tether"
it to the array when the discharge elements (4a) has been unlocked/displaced from the array and whilst it is being rotated by twisting (17) the tool (16). Each of the locating pin (18) and locating ring (19) can also help guide its respective element back into the array. A
discharge element embodiment may be provided that incorporates both a locating pin (18) and a locating ring (19).
Figure 4 shows examples of different tessellation configurations, and resulting diffuser rectangular face dimensions that can be realised by varying the combination and location of the discharge elements (4a) and part-hexagonal discharge elements (4b, 4c and 4d), Also shown are three different sets (A, R and C) of largely hexagonal discharge elements (4a), where each set has a different angle of inclination (a, p and 0, respectively) of its inclined discharge openings (5) (a <13 < 0). This of course changes the direction of the high momentum air jet (6a) relative to an axis that is perpendicular to the discharge plate (8).
Discharge elements (4a) with smaller angles of inclination are typically arranged and located closer towards a diffuser centreline than those with larger angles of inclination. This serves to reduce the likelihood of groups of high momentum air jets (6a) from "bundling" or colliding together, whereby Instead induction of room air (12) and low momentum airflow (6b) into the individual high momentum air jets (6a) is maximised. While three different sets of angle of inclination (cc, ri and 0) have been shown, many other angles of inclination are possible.
Referring now to Figure 5, a front view of two further configurations (I and II) of the discharge element (4a) are shown. Each of these embodiments is configured to reduce bundling of high momentum air Jets (6a), so as to maximise induction of both room air (12) and low momentum airflow (61,) into the individual high momentum air jets (6a).
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Received 19/06/2013 In this regard, Figure 5-1 shows inclined discharge openings (5) directed towards the hexagonal edge located at the 3 o'clock position, relative to the central axis of the discharge element (4a). Figure 5-11 shows inclined discharge openings (5) directed towards the hexagonal corner at the two o'clock position, relative to the central 5 axis of the discharge element (4a). The two angles of Inclination differ by 30 (or may differ by up to 30 in further embodiments). It has been observed that the combining of the discharge elements (4a) as shown in Figure 5-1 with those as shown in Figure 5-11 Into the same diffuser further minimises the risk of high momentum air jets (6a) from bundling/colliding together.
20 In further diffuser embodiments that include generally hexagonal discharge elements (4a), the side-view angles of inclination (as shown in Figure 4) may differ from one set of discharge elements (4a) to another. In addition, the front-view angles of Inclination (as shown in Figure 5) may differ between sets.
Figure 6 shows front (Figure 6-1), rear (Figures 6-11 and 6-III) and side section 15 views (Figures 6-IV, 6-V and 6-VI) of a fluffier embodiment of a ciiffUser. In this embodiment an adjustable slide damper plate (20) may be slid relative to the perforated inlet plate (13) to increase diffuser airflow, by maximising the relative open area of the two plates as shown in Figures 6-IL 6-IV and 6-V (i.e. "Open"). Alternatively, the slide damper plate (20) may be slid relative to the perforated inlet plate (13) to reduce 20 diffuser airflow, by minimising the relative open area of the two plates as shown in Figure 6-111 and Figure 6-VI (i.e. "Closed").
The access to the adjustable slide damper (20) can be from the front of the diffuser, such as via perforations (7) in the face of discharge plate (8).
Adjustable slide damper plate (20) may also include one or more pilot openings (21) that prevent slide damper plate (20) from restricting airflow to one or more of the hexagonal discharge elements (4a), which therefore remain active even when adjustable slide damper plate (20) is closed. This allows the discharge elements (4a) that remain active to continue to discharge high momentum air jets (6a), thereby providing stable diffuser operation and discharge direction control, such as by continuing to induce room air (12) and low momentum airflow (6b) (e.g. that escapes or leaks through slide damper plate (20), even AMENDED SHEET
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Received 19/06/2013 when damper (20) is closed).
Referring now to Figure 7, an air diftliser is illustrated to show which dimensions of the diffuser may typically be varied, depending on the given application, For example, each of the following dimensions may be varied:
LN ¨ the overall length of the diffuser (discharge plate (8));
LK ¨ the length of the diffuser perforated area (discharge perforations (7), length of the perforated inlet plate (13));
FIN ¨ the overall height of the diffuser (discharge plate (8));
HK ¨ the height of the diffuser perforated area (discharge perforations (7), length of the perforated inlet plate (13));
T ¨ the thickness of the diffuser, but which may also be fixed for any given length/height combination, As can also be seen in Figure 7, the centre points of some the discharge plate perforations (7) generally coincide with vertices of discharge elements (4a and 4b) arranged in the tessellation pattern as shown.
Referring now to Figure 8, a given discharge element (e.g. a primary air element (4a)) may be rotated for air discharge direction adjustment. In this case a suitable tool such as an Allen key A (or screwdriver, etc) is inserted through one of the perforations (7) in the face of the discharge plate (8). The Allen key A first pushes the element towards the rear of the diffuser so as to unlock it from a tessellated plane of discharge elements (e.g. by further compressing spring (15)). The Allen key A
Is then used to rotate the clement to one of a number of possible orientations (e.g.
five additional orientations in the case of a hexagonal element). The Allen key A
Is then released to allow the element to be moved (e.g. by the extension of spring (15)) and 2 5 lock back Into the tessellated plane.
The Allen key A may be configured such that it may only be inserted in one direction to engage the given discharge element. This can be such that the Allen key AMENDED SHEET
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Received 19/06/2013 lateral shaft L points in the direction of discharge of the particular element being moved, Thus, the shaft L provides visual feedback to a user of the current discharge direction and final discharge direction after adjustment.
As shown in Figures 9A and 9B, when different discharge elements in a diffuser have each been arranged in a number of differing positions, the airflow patterns P that may flow into an occupancy space S can be varied and altered. Figures 9A and 913 show one such configuration and, of course, many other airflow patterns are possible by filtering different ones of the discharge elements.
Whilst regular tessellated discharge element patterns have been shown and described, it should be understood that other tessellated patterns are possible, such as Arehimedean. In this regard, the part-hexagonal discharge elements may, for example, readily be replaced by triangular-shaped and/or diamond-shaped elements, etc, It will be appreciated by persons skilled in the art that numerous variations and/or modifications nuty be made to the air diffuser as shown in the specific embodiments without departing from the spirit or scope of the air diffuser 89 broadly described. The present embodiments arc, therefore, to be considered in all respects as Illustrative and not restrictive.
Advantageous Fsgiures of the Embodiments as Described Heroin The tessellated pattern of the discharge elements in the diffuser as described herein allows for easy locking in of elements in the plane, and ease of displacement, rotation, and realignment of a given element back into the plane. The tessellated pattern of the discharge elements can be in a plane having a regular or Archimedean pattern, etc.
Primary and/or secondary air jets, etc can be integrated into the discharge elements.
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Received 19/06/2013 The elements may take the form of e.g. polygonal disc-like elements, such as a regular polygon (e,g, hexagonal, square, eto) and an irregular polygon (e.g.
part-hexagonal, half-square, etc).
The discharge elements may be moulded of plastic, whereby the air jets can be more readily integrated into the elements.
The discharge elements can be located behind a powder-coated metal perforated discharge face, such. as can improve aesthetics, structural integrity, etc.
Each discharge element may be rotated (for air discharge direction adjustment) by inserting a suitable tool (e.g. Allen key) screwdriver, etc) through the perforated discharge face, to first push the element towards the rear of the diffuser so as to unlock It from the tessellated plane of discharge elements, and to then rotate it to a number of orientations (e.g. five additional orientations in the case of a hexagonal element; three additional orientations in the case of a square element, eto), before releasing it to lock back into the tessellated plane.
When e.g. an Allen key is employed, it may only be inserted such that its shaft points in the direction of discharge of the particular clement being moved, providing visual feedback of discharge direction during and after adjustment.
An air delivery system incorporating the diffirser 43 described herein can provide the potential for substantial energy savings and enhanced indoor air quality, as well as for improved thermal comfort.
The highly inductive discharge pattern of the diffuser can provide greater uniformity of temperature distribution in the occupied space than prior art standard grilles, thereby saving energy through improved temperature control, as well as improving thermal comfort, The highly inductive discharge pattern of the diffuser can improve mixing of the fresh air supplied by the diffuser with room air. thereby improving the removal of pollutants and contaminants by dilution, resulting in improved indoor air quality in comparison to prior art standard grilles.
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Received 19/06/2013 The highly inductive discharge pattern of the diffirser can reduce the vertical temperature gradient in the occupancy space In heating mode, thereby Improving heating performance, enhancing comfort, and reducing energy consumption in comparison to prior art standard grilles.
The highly inductive discharge pattern of the diffuser can provide stable, draught-free airflow patterns even when low temperature (less than 10 C) supply air Is discharged, thereby allowing fan energy savings to be achieved, due to the reduced airflow requirements of such systems in comparison to the performance of a prior art standard grilles.
The highly inductive discharge pattern and thermally decoupling design of discharge elements from the perforated face and mounting frame can reduce the risk of condensation in high humidity applications, such as the tropics, In comparison to both prior art standard grilles and prior art high induction diffusers.
The adjustability of the discharge pattern allows airflow patterns to be manually adjusted to suit the shape of the occupancy space, without a visible impact on the aesthetics of the diffuser, unlike both prior art standard grilles and prior art high Induction diffusers.
The shallow depth of the diffuser can allow for installation in restricted spaces.
The design of the diffuser can allow larger supply air quantities to be discharged with respect to the face area of the diffuser than is realised by prior art high induction side-wall diffusers.
The low operating pressure of the diffuser can reduce energy consumption and can make the diffuser suitable for low pressure HVAC systems, such as fan-coil units.
The low regenerated noise of the diffuser can make It suitable for noise sensitive applications, such as hotel rooms.
The suitability of the diffuser to both short throw and long throw applications, without creating draughts or stagnation in the occupancy space, can improve thermal AMENDED SHEET
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Received 19/06/2013 comfort and reduce commissioning costs, The suitability of the diffuser to HVAC systems with varying airflow tale, without creating draughts or stagnation in the occupancy space, can improve thermal comfort.
5 The flush and uniformly perforated face of the diffuser is both aesthetically appealing and easy to clean.
The diffuser discharge pattern can reduce the rate at which dirt accumulates on the flout face of the diffuser (known as "smudging") thereby further improving the aesthetics of the diffuser and reducing cleaning costs, 10 As the adjustable components of the diffuser are only accessible via a tool, unintended adjustment of the diffuser discharge pattern can be averted, such as may OCCUT for example by cleaners wiping the face of the diffuser.
The design of the diffuser can allow low cost fabrication to be achieved due to the simplicity of the components and the ability to achieve economies of scale from the 15 mass production of the discharge elements, thereby making the diffUser affordable for standard side-wall applications, such as hotel rooms.
The term "comprising" (and its grammatical variations) as used herein are used in the inclusive sense of "including" (i.e. not limited just to the listed features) and thus is not to be interpreted in the sense of "consisting only of'.
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Claims (47)

1. An air diffuser comprising a plurality of discharge elements, the discharge elements being configured such that they are able to be arranged to form a tessellation of discharge elements in a plane, and wherein at least one of the discharge elements is able to be adjusted into a new orientation in the tessellation plane.

2. An air diffuser in accordance with claim 1, wherein a plan shape of each discharge element is substantially in the form of a polygon.

3, An air diffuser in accordance with claim 2, wherein, for at least some of the discharge elements, the polygon is mathematically regular.

4. An air diffuser in accordance with claim 3, wherein said at least some discharge elements take the form of a hexagon.

5. An air diffuser in accordance with any one of the preceding claims, wherein the tessellation pattern of the discharge elements in the plane is Archimedean or regular.

6. An air diffuser in accordance with any one of the preceding claims, wherein each of the discharge elements is generally plate-like.

7. An air diffuser in accordance with any one of the preceding claims, wherein the discharge elements are arranged in the diffuser so as to abut.

8. An air diffuser in accordance with claim 7, wherein the at least one discharge element is able to be independently displaced out of the tessellation plane, generally along an axis that is perpendicular to the tessellation plane, and independently rotated about that axis into the new orientation, before being displaced back along the axis and back into the tessellation plane.

9. An air diffuser in accordance with claim 8, wherein the at least one discharge element is able to be rotated to more than one new orientation.

10. An air diffuser in accordance with claim 8 or 9, wherein, when the at least one discharge element has a mathematically regular polygon plan shape, the number of new orientations to which the element can be rotated corresponds to or is a fraction of Its number of aides,

11. An air diffuser in accordance with any one of the preceding claims, wherein at least one of the discharge elements is configured and is able to be arranged in the diffuser so as to discharge a primary air stream in a direction that is generally inclined to an axis that is perpendicular to the tessellation plane.

12. An air diffuser in accordance with claim 11, when dependent on any one of claims 8 to 10, wherein changing the orientation of the at least one primary air stream discharge element varies the airflow direction of the primary air stream.

13. An air diffuser in accordance with claim 12, wherein the at least one primary air stream discharge element comprises at least one discharge canal integrated therein, with the primary air stream being discharged by the at least one discharge canal.

14. An air diffuser in accordance with claim 13, wherein the at least one discharge canal is inclined to the perpendicular axis of the tessellation plane of discharge elements, whereby the primary air stream is generally discharged in a direction that is similarly inclined to the axis.

15. An air diffuser in accordance with any one of claims 11 to 14, further comprising a perforated discharge plate, wherein the primary air stream is discharged through at least one of a plurality of the perforations in the discharge plate,

16. An air diffuser in accordance with claim 15, wherein in use the discharge plate is arranged in a plane that is parallel to the tessellation plane of discharge elements.

17. An air diffuser in accordance with claim 16, wherein an inside face of the discharge plate closely faces or abuts a discharge face of the discharge elements,

18. An air diffuser in accordance with claim 16, wherein the centre points of some the discharge plate perforations are generally coincident with vertices of the given discharge elements arranged in the tessellation.

19. An air diffuser in accordance with any ono of the preceding claims, wherein the diffuser is configured to discharge at least one secondary air stream in close proximity to a primary air stream.

20, An air diffuser in accordance with claim 19, wherein the secondary air stream is of substantially lower momentum than the primary air stream to which it is in close proximity.

21. An air diffuser in accordance with claim 20, wherein the secondary air stream is induced by the primary air stream to which it is in close proximity to form one combined air stream.

22. An air diffuser in accordance with claim 21, wherein the discharge direction and/or throw of the combined air stream is largely determined by the discharge direction or throw respectively of the primary air steam to which the secondary air stream is in close proximity.

23. An air diffuser in accordance with any one of claims 19 to 22, wherein the secondary air stream is discharged by at least one opening integrated into at least one of the discharge elements.

24. An air diffuser in accordance with any one of claims 19 to 23, wherein the secondary air stream is discharged by at least one opening defined between discharge elements abutting in the tessellation.

25. An air diffuser in accordance with any one of claims 19 to 24, wherein the secondary air stream is discharged through at least one of discharge perforation of a discharge plate of the diffuser.

26. An air diffuser in accordance with any one of the preceding claims, further comprising an inlet plate that is located upstream of the tessellation of discharge elements.

27. An air diffuser in accordance with claim 26, wherein at least one discharge element is attached to the inlet plate.

28. An air diffuser in accordance with claim 26 or 27, wherein the inlet plate is located so as to be clear of the tessellation of primary air stream discharge elements.

29. An air diffuser in accordance with any one of claims 26 to 28, wherein a plane of the inlet plate is generally parallel to the tessellation plane of discharge elements.

30. An air diffuser in accordance with any one of claims 26 to 29, wherein the inlet plate is perforated.

31. An air diffuser in accordance with any one of claims 26 to 30, further comprising a biasing mechanism for at least one of the discharge elements, the biasing mechanism arranged between that discharge element and the inlet plate 30 as to exert a force directed against the inlet plate end to bias that discharge element into engagement in the tessellation plane and into engagement with adjacent discharge elements.

32. An air diffuser in accordance with claim 31, wherein the biasing mechanism is configured such that, upon application to that discharge element of a disengaging force in a direction towards the inlet plate and that is greater than the biasing force, that discharge element is able to disengage from the tessellation of discharge elements.

33. An air diffuser in accordance with claim 32, wherein the disengaging force is able to be applied to that discharge element via an adjustment tool, such as may be inserted through a given perforation of a discharge plate of the diffuser.

34. An air diffuser In accordance with claim 32 or 33, wherein, once that discharge element has been disengaged from the tessellation plane, rotation of the adjustment tool about an axis that is generally perpendicular to the tessellation plane, rotates the discharge element accordingly about the same axis.

35. An air diffuser in accordance with claim 34, wherein the discharge element is able to be re-engaged into the tessellation plane of discharge elements in one or more different orientations about the perpendicular axis.

36. An air diffuser in accordance with claim 35, wherein the discharge element is able to be re-engaged once the disengaging force is removed.

37. An air diffuser comprising a plurality of discharge elements, the discharge elements being configured such that they are able to be arranged in a plane, wherein at least one discharge element is able to be displaced from the plane, rotated about an axis that is generally perpendicular to the plane and, once a given rotational position has been reached, re-displaced back into the plane and wherein at least one of the discharge elements is able to be adjusted into a new orientation in the plane.

38. An air diffuser in accordance with claim 37, the air diffuser being otherwise as defined in any one of claims 1 to 36.

39. A ducting and/or air supply system incorporating at least one air diffuser In accordance with any one of the preceding claims.

40. An air diffuser comprising:
a frame; and a plurality of discharge elements positioned within or adjacent to the frame, each discharge element abutting against or closely facing at least one other discharge element, the discharge elements having a plan shape of a polygon, and wherein at least one of the discharge elements is able to be adjusted into a new orientation in the flame.

41. An air diffuser in accordance with claim 40, wherein at least one of the discharge elements is configured to discharge an air stream in a direction that is inclined with respect to an axis that extends generally perpendicularly from a downstream face of the discharge element.

42. An air diffuser in accordance with claim 40 or 41, wherein the discharge elements are arranged in a regular repeating pattern.

43. An air diffuser in accordance with claim 42, wherein the discharge elements are arranged in a tessellated pattern and in a manner as defined in any one of claims I to 37.

44. An air diffuser in accordance with any one of claims 40 to 42, wherein each discharge element comprises discharge passages, the discharge passages each arranged to expel an air stream, with at least one of the discharge elements comprising at least one discharge passage that is configured to discharge a high velocity air stream and at least one discharge passage that is configured to discharge a low velocity air stream.

45. An air diffuser in accordance with claim 43, wherein the at least one high velocity discharge passage is generally arranged in the centre of the discharge element and the at least low velocity discharge perforation is generally arranged adjacent to the at least one high velocity discharge passage but away from the centre of the discharge element.

46. An air diffuser in accordance with claim 43 or 44, wherein the at least one high velocity discharge passage is defined by a discharge canal extending through the discharge element.

47. An air diffuser in accordance with claim 45, wherein a central axis of the discharge canal is inclined to the perpendicular axis so as to direct at least one air stream in an angled direction from the diffuser.