WO2011022788A1

WO2011022788A1 - An air diffuser and an air circulation system

Info

Publication number: WO2011022788A1
Application number: PCT/AU2010/001117
Authority: WO
Inventors: Sean Michael Johl Badenhorst
Original assignee: Kaip Pty Limited
Priority date: 2009-08-31
Filing date: 2010-08-31
Publication date: 2011-03-03
Also published as: AU2010286350A1; US20120190293A1; NZ599123A; CN102713452A

Abstract

An air diffuser comprising a body, at least one swirl pattern discharge element and at least one jet pattern discharge element, wherein the jet pattern discharge element is manipulable to vary the airflow direction angle of a discharged jet pattern of air relative to an axis perpendicular to a discharge face of the swirl pattern discharge element to thereby alter the angle of the air discharged from the swirl pattern discharge element.

Description

AN AIR DIFFUSER AND AN AIR CIRCULATION SYSTEM

Field of the Invention The present invention relates to an air diffuser. Embodiments of the invention find particular, but not exclusive, use as a long throw sidewall swirl diffuser or a ceiling swirl diffuser, as part of an installed air delivery system.

Background of the Invention

Many buildings with large occupancy spaces have air delivery systems in which the air is delivered to and mixed into the occupancy space via one or more side blow diffusers that provide long horizontal throws. These diffusers are typically located in a sidewall or bulkhead.

Such systems usually deliver supply air into the space through eyeball, single-cone or multi-cone nozzles that create high velocity jets with long horizontal throws. Discharge direction adjustability is usually achieved via nozzle cones that can be swivelled about horizontal and/or vertical axes or by means of a ball in a socket configuration in which the nozzle is incorporated in the ball. Each of these configurations allows the discharge direction to be manually adjusted in up to two planes - up and down and left and right - and in some instances the direction of the nozzle or cones may be reversed to increase or decrease diffuser throw by

concentrating or dispersing the discharged airflow

pattern. For each nozzle, discharge direction adjustment is typically manual, or an actuator (electric, pneumatic or thermally powered) may swivel the nozzle or the nozzle assembly upwards and downwards for cooling and heating applications, respectively.

In order for an isothermal air stream to achieve a given axial throw to a fixed terminal velocity, the requisite velocity of the air stream as it is discharged axially from a circular nozzle is inversely proportional to the volume flow rate of the discharged air stream.

Consequently, in order to achieve a given throw from a nozzle, the nozzle discharge diameter needs to be

increased in proportion to the increase in volume flow rate to realise the requisite inverse discharge velocity relationship, resulting in increased nozzle discharge size and reduced discharge velocity the larger the airflow rate to be discharged from the nozzle. These factors, in turn, reduce the stability of the discharged air stream and increase temperature and velocity deviations from the average in the space. In other words, the suitability of side blow nozzles to spaces requiring uniform temperature and velocity distribution, especially if draught-free comfort is required, decreases the greater the volume flow rate to be discharged by each nozzle.

To overcome this limitation, when each side blow diffuser is to discharge a large volume flow rate of air, high induction long throw side blow swirl diffusers are increasingly being used as an alternative to nozzles.

This is because swirl diffusers induce large quantities of room air into the supply air stream and rapidly break down the temperature differential between supply and room air. Such highly inductive discharge of large airflow rates is able to produce stable long throws with low terminal velocities whilst largely equalising supply air stream temperature with room air temperature, achieving more uniform temperature and velocity distribution and less draught risk.

In some instances the axial (i.e. horizontal) throw of such side blow swirl diffusers is manually adjustable. However, as throw is a function of the discharged air flow rate, side blow swirl diffusers of the prior art are required to always discharge a constant volume flow rate of air so as to avoid over-throw and under-throw from occurring, and hence they should not be used in

conjunction with variable speed drive fans or similar devices that result in variable airflow rates from each diffuser (e.g. a reduced airflow rate is not permitted to save fan energy during times of low cooling or low heating demand) . The discharge direction of side blow swirl diffusers is often adjustable, with adjustment generally being manual or by an electric or a pneumatic actuator for applications requiring the diffuser discharge angle to be automatically directed more strongly downwards the hotter the supply air relative to room air so as to prevent stratification of the warm supply air by compensating for supply air buoyancy. This is usually done, in the prior art, by swivelling the entire swirl diffuser about a horizontal axis to allow the discharged air stream

direction to be adjusted upwards or downwards, and as a result, the diffuser front face usually extends well proud of the surface to which the diffuser assembly is mounted, which makes it dominant and unsightly in the space.

Moreover, swivelling the entire diffuser makes it

especially noticeable if diffusers in a row have discharge angles that are out of alignment (which is extremely difficult to overcome due to tolerance limitations) and requires the mounting flange, within which the diffuser swivels, to be extremely bulky. Additionally, this prior art design causes the swivel axis to be located proud of the mounting surface, resulting in the optional swivel mechanism actuator being visible, which is unsightly.

These factors combined present aesthetic challenges that severely restrict the acceptance of side blow swirl diffusers of the prior art as an air distribution solution for large spaces. Moreover, swivelling the entire bulk of the diffuser restricts the realistically achievable swivel angle to an arc of approximately 40°, which allows a mere 20° downward swivel from the horizontal if the diffuser mounting flange is attached to a vertical surface such as a wall . This is less than the downward discharge angle of at least 30° from the horizontal that is usually required to achieve effective and efficient heating.

Thermal actuators that are powered and regulated by supply air temperature alone are usually not used for such prior art diffusers, as such thermal actuators suffer from excessive hysteresis when swivelling such large and heavy diffusers and struggle to overcome the inconsistent resistance and forces required to deform the canvas bellows used by the prior art to create an air tight seal . Moreover, the large swivel forces involved require

excessive thermal element bulk, making them unacceptably slow to respond to temperature changes and extremely expensive. This limitation further restricts the use of such side blow swirl diffusers of the prior art in

applications that require actuators for swivelling to those instances where the added expense of wiring and controls can be justified. Finally, due to the constant airflow rate requirements of such prior art swirl

diffusers, pre-occupancy warm up of the space cannot occur at reduced airflow rates, which is often desired, as return air ducts, especially of spaces for large

gatherings of people, such as exhibition halls, are generally not sized for 100% airflow rate. This is because such spaces require the delivery of a large amount of (conditioned) outdoor air to the space during occupancy to ensure appropriate indoor air quality. A similar amount of air has to be relieved from the space: this relief air is therefore usually not returned to the air handling unit and hence return air ducts and dampers are downsized accordingly. Pre-occupancy warming up or cooling down of the space, however, occurs without the need for outdoor air, which should ideally not be

introduced anyway during this phase so as not to waste energy heating or cooling this outdoor air. As a result, the supply airflow rate is usually reduced during the pre-occupancy warming-up or cooling-down phase of such spaces, both because the return air ducts and dampers are usually sized for less than 100% airflow and because introducing unneeded outdoor air during this phase would waste energy. However, the supply airflow rate to each side blow swirl diffuser of the prior art should ideally not be reduced during operation, as this would reduce diffuser throw, diminishing diffuser performance, which would be especially detrimental when the diffuser is angled downwards for heating, as this is when it, in fact, generally requires the highest airflow rate possible to maximise throw for effective penetration of the buoyant supply air stream down to floor level, so as to achieve efficient heating of the space. Consequently, either energy has to be wasted introducing and conditioning outdoor air when it is not required, or return air ducting and damper sizes need to be increased to handle 100% airflow, which is usually extremely costly even if the space is available, and in both cases substantial fan energy is wasted. The same pre-occupancy heating issues apply to ceiling swirl diffusers of the prior art, which, in high spaces, usually have adjustable discharge direction and are directed to discharge downwards (manually or by actuators) during heating mode so that the warm supply air stream penetrates down to floor level. Here, too, airflow rates to ceiling swirl diffusers of the prior art should not be reduced during heating mode, as this would

adversely impact heating efficiency and effectiveness in the space.

Summary of the Invention

In a first aspect, the present invention provides an air diffuser comprising a body, at least one swirl pattern discharge element and at least one jet pattern discharge element, wherein the jet pattern discharge element is manipulable to vary the airflow direction angle of a discharged jet pattern of air relative to an axis

perpendicular to a discharge face of the swirl pattern discharge element to thereby alter the angle of the air discharged from the swirl pattern discharge element .

In one embodiment, the body may be substantially cylindrical in shape. Moreover, the swirl pattern

discharge element may include a plurality of radial vanes arranged to discharge a swirl pattern of air and the jet pattern discharge element may include a nozzle arranged to discharge a jet pattern of air.

In turn, the nozzle discharge direction may be adjustable relative to an axis perpendicular to the discharge face of the diffuser. Moreover, the volume flow rate of the jet pattern discharge element may be adjusted by a damper located at least partly within the nozzle. On application of a largely constant pressure of air to the diffuser, the embodiment may be arranged such that adjustment of the nozzle damper may alters the diffuser axial throw of the combined jet pattern and swirl pattern of discharged air relative to the plane of the swirl diffuser discharge face.

In some embodiments, adjustment of at least one of the diffuser discharge direction, axial throw and volume flow rate may be performed by at least one actuator,

Moreover, the operation of the diffuser may be performed by actuator driven manipulation of at least one of the elements. In some embodiments, manipulation of at least one element may be performed by at least one

actuator that is powered and regulated by supply air temperature or pressure alone .

The volume flow rate of the swirl discharge pattern may be adjustable or preset by a damper upstream of, or integrated into, embodiments which include radial vanes.

On application of a largely constant volume flow rate of air to the diffuser, adjustment of the swirl discharge pattern volume flow rate brings about a change in supply air pressure to the diffuser thereby changing the

discharge velocity from the nozzle, which in turn alters the diffuser axial throw of the combined jet pattern and swirl pattern of discharged air relative to the plane of the swirl diffuser discharge face.

In a second aspect, the present invention provides an air diffuser assembly for use in combination with a wall, bulkhead, ceiling or floor air delivery system comprising an air diffuser in accordance with the first aspect of the invention and at least one mounting device arranged to connect the air diffuser to the wall, bulkhead, ceiling and/or floor. In a third aspect, the present invention provides an air diffuser including a body, at least one swirl

discharge pattern element and at least one jet discharge pattern element, wherein, on the application of a largely constant air supply pressure, the diffuser maintains a largely constant axial throw of the combined jet and swirl patterns of discharged air along an axis perpendicular to the plane of the swirl diffuser discharge face as the diffuser supply airflow rate is varied,

In one embodiment, the air diffuser in accordance with the third aspect of the invention may further include the features of the first aspect of the invention.

In another embodiment, the air diffuser assembly in accordance with the second aspect of the invention may further include the features of the third aspect of the invention.

In a fourth aspect, there is provided an air diffuser comprising a body, at least one swirl discharge pattern element and at least one jet discharge pattern element arranged to be manipulated to alter a diffuser axial throw discharge direction and volume flow rate.

Detailed Description of the Drawings Notwithstanding any other forms which may fall within the scope of the present invention, a preferred embodiment will now be described, by way of example only, with

reference to the accompanying drawings in which:

Figure 1 is a diagram illustrating three typical side blow swirl diffusers of the prior art with manually

adjustable axial throw and up/down discharge direction adjustment by means of an optional actuator;

Figure 2 is a diagram illustrating embodiments of the invention as side blow swirl diffusers with adjustable discharge direction;

Figure 3 is a diagram illustrating embodiments of the invention as side blow swirl diffusers with adjustable discharge direction and configurations for altering axial throw;

Figure 4 is a diagram illustrating an embodiment of the invention as a side blow swirl diffuser with

adjustable discharge direction and adjustable axial throw;

Figure 5 is a diagram illustrating an embodiment of the invention as a side blow swirl diffuser with

adjustable discharge direction and adjustable airflow rate;

Figure 6 is a diagram illustrating an embodiment of the invention as a side blow swirl diffuser with

adjustable discharge direction, adjustable axial throw and adjustable airflow rate;

Figure 7 is a diagram illustrating embodiments of the invention as side blow swirl diffusers with adjustable discharge direction, adjustable axial throw and adjustable airflow rate, in which discharge direction and airflow rate are adjustable by means of actuators;

Figure 8 is a diagram illustrating embodiments of the invention as ceiling swirl diffusers with adjustable axial throw and adjustable airflow rate, in which the axial throw and the airflow rate are adjustable by means of actuators; and

Figure 9 is a diagram illustrating embodiments of the annular damper assembly; and

Figure 10 is a diagram illustrating an embodiment of an air diffuser arranged to be manipulable to alter

diffuser axial throw, discharge direction and volume flow rate . Detailed Description of the Preferred Embodiment

General Overview

The embodiment, as described herein, relates

generally to an air diffuser assembly for side blow or ceiling discharge with an air supply supplied from a pressure plenum or duct. The assembly comprises an

optional mounting flange on the front face of the diffuser that may be used to secure the diffuser to a duct,

bulkhead or wall.

Reference numerals in the following description represent like components or features in the related

Figures .

Figure 1 is a diagram illustrating the front and side section views of typical side blow swirl diffusers of the prior art, in which:

Sub-Figures i-a, i-b and i-c show supply air (14) delivered to a side blow swirl diffuser with a largely cylindrical housing (1) mounted to a duct or pressure plenum (2) by means of a flange (3) with bellows (4) connecting flange (3) to the diffuser inlet neck (5) to allow air tight swivelling of the diffuser in a vertical plane through angle a about horizontal axis (6) connected to actuator "A" thereby altering the discharge angle of the supply air stream (8a or 8c) from swirl vanes (16) relative to an axis perpendicular to flange (3) and

including a central discharge hub (7) with adjustable distance from the diffuser discharge face (13) to vary the axial throw of the discharged swirl air stream from long (8c) to short (8a) ;

Sub-Figures ii-a, ii-b and ii-c supply air (14) delivered to a side blow swirl diffuser with a largely- cylindrical housing (1) mounted to a duct or pressure plenum (2) by means of a flange (3) with bellows (4) connecting flange (3) to the diffuser inlet neck (5) to allow air tight swivelling of the diffuser in a vertical plane through angle a about horizontal axis (6) connected to actuator "A" thereby altering the discharge angle of the supply air stream (8a or 8c) from swirl vanes (16) relative to an axis perpendicular to flange (3) and including a retractable discharge ring (9) with adjustable distance from diffuser discharge face (13) to vary the axial throw of the discharged swirl air stream from long (8c) to short (8a) ;

Sub-Figures iii-a, iii-b and iii-c show supply air (14) delivered to a side blow swirl diffuser with a largely cylindrical housing (1) mounted to a duct or pressure plenum (2) by means of a flange (3) with bellows (4) connecting flange (3) to the diffuser inlet neck (5) to allow air tight swivelling of the diffuser in a

vertical plane through angle a about horizontal axis (6) connected to actuator "A" thereby altering the discharge angle of the supply air stream (8a or 8c) from swirl vanes (16) relative to an axis perpendicular to flange (3) and including a plug damper (10) with adjustable distance from the inlet to a centrally located nozzle (11) to vary the axial throw of the discharged swirl air stream from long (8c) to short (8a) by means of an axial jet (12) of adjustable airflow rate.

In all of the above Figures, swivelling the diffuser through arc a in a vertical plane, by means of manual adjustment or actuator (A) , is generally required to adjust discharge direction downwards for heating and upwards for cooling. Figure 2 illustrates the front and side section views of embodiments of the invention, in which:

Sub-Figures i-a and i-b show supply air (14)

delivered to a side blow swirl diffuser with a largely cylindrical housing (1) mounted to a wall, duct or

pressure plenum (2) by means of a discharge face flange (3a) flush with discharge face (13) and including a

centrally located cylindrical pilot nozzle (lla) with adjustable angle of inclination (/?) about axis (6) to alter the discharge angle of pilot jet (12) in one plane relative to an axis perpendicular to the diffuser

discharge face (13) thereby similarly adjusting the

discharge direction of discharged swirl air stream (8) from swirl vanes (16) over arc β in one plane.

Sub-Figures ii-a and ii-b show supply air (14) delivered to a side blow swirl diffuser with a largely cylindrical housing (1) mounted to a wall, duct or

centrally located tapered pilot nozzle with rounded inlet (lib) in largely hemispherical housing (15a) with

adjustable angle of inclination (β) about axis (6) , which in turn is rotatable about the diffuser central axial axis by angle θ, to alter the discharge angle of pilot jet (12) in up to two planes relative to an axis perpendicular to the diffuser discharge face (13) thereby similarly

adjusting the discharge direction of discharged swirl air stream (8) from swirl vanes (16) over arc β in up to two planes .

Sub-Figures iii-a and iii-b show supply air (14) delivered to a side blow swirl diffuser with a largely cylindrical housing (1) mounted to a wall, duct or

pressure plenum (2) by means of a discharge face flange (3a) flush with discharge face (13) and including a centrally located conical pilot nozzle (lie) in largely- spherical housing (15b) within socket (15c) with

adjustable angle of inclination (β) about a central point (6a) to alter the discharge angle of pilot jet (12) in up to two planes relative to an axis perpendicular to the diffuser discharge face (13) thereby similarly adjusting the discharge direction of discharged swirl air stream (8) from swirl vanes (16) over arc β in up to two planes,

It will be apparent to the person skilled in the art that further embodiments of the invention may be created based on the principles presented, for example by

combining elements of the individual embodiments described above .

For example, there may be provided an embodiment of the invention in which the diffuser neck (5) is mounted to a duct, wall or plenum rather than such mounting being via a discharge face flange (3a) .

The above embodiments provide the following

advantages over the prior art:

(i) The diffuser assembly may be more compact than is possible with the prior art, as flange 3a may be smaller than flange 3 in Figure 1.

(ii) The diffuser discharge face (13) may be largely flush mounted with the wall, duct or plenum (2) to which the diffuser is attached, whereas the diffuser discharge face (13) in Figure 1 protrudes from the wall, duct or plenum (2) resulting in an obtrusive diffuser assembly. (iii) The diffuser discharge face (13) remains

stationary relative to the wall, duct or plenum (2) , whereas the angle of diffuser face (13) relative to the wall, duct or plenum (2) in Figure 1 changes as diffuser discharge angle changes, which generally causes an eyesore when diffusers in a row are out of angular

alignment, typically due to swivel tolerance limitations.

(iv) The swivel arc (β) , drawn at 60" (though the invention is not limited to this value) , may be greater than swivel arc (α) , drawn at 40° (typical of the prior art) in Figure 1, without increasing overall diffuser -size . The greater swivel arc in the invention improves cooling and heating performance and allows for a greater range of heights at which the diffuser may be installed.

Figure 3 illustrates the rear and side section views of embodiments of the invention, with additional

components to those shown in Figure 2 to alter diffuser axial throw, in which:

Sub-Figures i-a, ii-a and iii-a show retractable discharge ring (9) with adjustable distance from diffuser discharge face (13) to vary the axial throw of the

discharged swirl air stream from short (8a) to medium (8b) to long (8c) , respectively, for a largely constant airflow rate of supply air (14) to the diffuser by extending discharge ring (9) towards the plane of the diffuser discharge face (13) ;

Sub-Figures i-a, ii-a and iii-a show a pilot nozzle discharge opening reducer (18a) and a pilot nozzle of reduced diameter (18b) as additions to, or alternatives to, the standard pilot nozzles (11a, lib and lie)

illustrated with pilot nozzle discharge openings ranging from smallest to medium to largest, respectively, to discharge increasing pilot jet airflow rates for a largely constant diffuser operating pressure of the supply air (14) thereby providing increasing pilot jet throw (12a, 12b and 12c) to increase the throw of the discharged swirl air stream from short (8a) to medium (8b) to long (8c) , respectively;

Sub-Figures i-a and i-b, ii-a and ii-b, and iii-a and iii-b show fixed perforated plate dampers (17a, 17b and 17c) of high, medium and low open area, respectively, upstream of swirl vanes (16) to increase diffuser

operating pressure for a largely constant airflow rate of supply air (14) to the diffuser, thereby increasing the discharge velocity of the pilot nozzle so as to discharge a short pilot jet (12a) or a medium pilot jet (12b) or a long pilot jet (12c) that in each case increases the throw of the discharged swirl air stream from short (8a) to medium (8b) to long (8c) , respectively;

Sub-Figures i-a and i-b, ii-a and ii-b, and iii-a and iii-b show perforated nozzle dampers (10a, 10b and 10c) that are largely closed, partly open and fully open, respectively, thereby increasing pilot jet (11a, lib and lie) discharge velocity and volume flow rate at a largely constant operating pressure of the diffuser supply air (14) to increase pilot jet throw from short (12a) to medium (12b) to long (12c) so as to increase the throw of the discharged swirl air stream from short (8a) to medium (8b) to long (8c) , respectively.

The above four methods of altering diffuser throw may be used individually or in combination with one another, and may be applied to any of the invention embodiments presented in Figure 2.

Figure 4 illustrates the rear and side section views of an embodiment of the invention, in which:

Sub-Figures i-a, i-b, ii, iii-a and iii-b show an adjustable annular damper assembly upstream of swirl vanes (16) that provides an adjustable increase in the operating pressure of a largely constant airflow rate of supply air (14) to the diffuser as the annular damper assembly is adjusted from fully open (17d) through partially open (17e) to largely closed (17f) thereby increasing the discharge velocity and flow rate from the pilot nozzle (Ha) to effect a change from a short pilot jet (12a) through to a long pilot jet (12c) so as to increase the throw of the discharged swirl air stream from short (8a) to long (8c) .

Figure 5 illustrates the rear and side section views of an embodiment of the invention, in which:

Sub-Figures i-a, i-b, ii, iii-a and iii-b show an adjustable annular damper assembly upstream of swirl vanes (16) that maintains a largely constant pressure of a variable volume supply air stream (14) to the diffuser as the supply air flow rate (14) increases from low (i-a and i-b) , in which the annular damper is largely closed (17f) , through to medium (ii) , in which the annular damper is partially open (17e) , to high (iii-a and iii-b) , in which the annular damper is fully open (17d) , so that a largely constant throw of the pilot jet (12c) is maintained, thereby providing a largely constant throw of the

discharged swirl air stream as its airflow rate is

increased from low (8d) to high (8e) .

Figure 6 illustrates the rear and side section views of a further embodiment of the invention to that shown in Figure 5, in which:

Sub-Figures i-a, i-b, ii, iii-a and iii-b show, in addition to the components and functionality shown in Figure 5, an adjustable nozzle damper that, for a supply air stream (14) of largely constant pressure, progressively increases the discharge velocity and volume flow rate of pilot nozzle (lie) from minimum, when the nozzle damper is largely closed (10a) , through to medium, when the nozzle damper is partially open (10b) , to

maximum, when the nozzle damper is fully open (10c) , thereby increasing pilot jet throw from short (12a) through to long (12c) to allow the throw of the discharged swirl air stream to be set from short (8a) through to long (8c) .

Figure 7 illustrates the rear and side section views of a further embodiment of the invention to those shown in Figure 2, Figure 3, Figure 4, Figure 5 and Figure 6, in which:

Sub-Figures i-a, i-b, ii-a, ii-b, iii-a and iii-b show pilot nozzle discharge direction actuator (Al) that swivels the pilot nozzle (11a, lib and lie) about pivot axis (6), and annular damper actuator (A2) that opens and closes annular damper assembly (17e) . Pilot nozzle discharge direction actuator (Al) may be thermally powered and regulated by supply air stream (14) temperature, or electrically or pneumatically powered or regulated.

Annular damper actuator (A2) may be pressure powered and regulated by supply air stream (14) pressure, or

electrically or pneumatically powered or regulated.

Not shown in the illustrations above, for reasons of simplicity, are embodiments of the invention incorporating components and functionality described in Figure 3 and Figure 6.

Figure 8 illustrates the rear and side section views of embodiments of the invention as a ceiling diffuser, in which:

Sub-Figures i-a, i-c, i-d, i-e, ii-a, ii-b show a round and an annular pilot nozzle (Sub-Figures i-a and ii-a, respectively) that discharge a jet pattern (12) with round and annular cross sections, respectively.

Sub-Figures i-a, i-b, i-c, i-d, i-e, ii-a, ii-b and ii-c show pilot nozzle damper actuator (A3) that opens (10a) and closes (10c) the pilot nozzle damper, and annular damper actuator (A2) that opens and closes the annular damper assembly from largely closed (17f) to fully open (17d) . Pilot nozzle damper actuator (A3) may be thermally powered and regulated by supply air stream (14) temperature, or electrically or pneumatically powered or regulated. Annular damper actuator (A2) may be pressure powered and regulated by supply air stream (14) pressure, or electrically or pneumatically powered or regulated.

Sub-Figures i-b, i-c, i-d, i-e, ii-b and ii-c show, for a largely constant pressure of supply air (14) , horizontal flow of the discharged swirl air stream (8d and 8f) when the pilot nozzle damper to pilot jet (11a and lid) is closed (10a) , and downward discharge of pilot jet (11a and lid) when the pilot nozzle damper is open (10c) , in turn causing the discharged swirl air stream to be redirected downwards (8e and 8g) .

Sub-Figures i-a, i-b, i-c, i-d, i-e, ii-a, ii-b and ii-c show, for a largely constant pressure of supply air (14) , a low volume flow rate swirl discharge (8d and 8e) when the annular damper is largely closed (17f) and a high volume flow rate swirl discharge (8f and 8g) when the annular damper is fully open (17d) .

Sub-Figures i-c, i-e and ii-c show, for a largely constant pressure of supply air (14), that pilot jet (12) redirects a discharged air stream of both a low flow rate (8e) and a high flow rate (8g) downwards to a throw of largely equal axial distance from the plane of the

diffuser discharge face (13). Figure 9 illustrates the rear and side section views of embodiments of the invention, in which:

Sub-Figures i-a and i-b show the annular damper assembly comprising at least one fixed damper blade (17k) , a slide damper blade (17gl) and a damper opening (17h) .

The slide damper blade (17gl) may move from the fully open position behind the fixed damper blade (17k) , in which case each damper opening (17h) has a width approximately equal to the width of the fixed damper blade (17k) , to the fully closed position (17i) .

Sub-Figures ii-a and ii-b show the annular damper assembly comprising at least one fixed damper blade (17k) , two slide damper blades (17gl and 17g2) and a damper opening (17h) . The slide damper blades (17gl and 17g2) may move from the fully open position behind the fixed damper blade (17k) , in which case each damper opening (17h) has a width approximately equal to twice that of the fixed damper blade (17k) , to the fully closed position (17i) .

Sub-Figures iii-a and iii-b show the annular damper assembly comprising at least one swivel damper blade (17j) and a damper opening (17h) . Swivel damper blades (17j) may be mechanically linked to operate in opposed direction (as shown) or parallel (not shown for simplicity) to move from the fully open position to the fully closed position (17i) .

Figure 10 illustrates the rear and side section views of an embodiment of the invention arranged to be

manipulated to alter diffuser axial throw, discharge direction and volume flow rate, in which:

Sub-Figures i-a, ii-a and iii-a show retractable discharge ring (9) with adjustable distance from diffuser discharge face (13) to vary the axial throw of the discharged swirl air stream from short (8a) through medium (8b) to long (8c) , respectively, for a largely constant airflow pressure of supply air (14) to the diffuser by extending discharge ring (9) towards the diffuser

discharge face plane (13) ;

Sub-Figures i-a and i-b, ii-a and ii-b, and iii-a and iii-b show pilot nozzle (lla) largely closed, partly open and fully open, respectively, due to fixed perforated nozzle dampers (10c and 10b) , thereby increasing pilot jet discharge velocity and volume flow rate at a largely constant operating pressure of the diffuser supply air (14) to increase pilot jet throw from short (12a) through medium (12b) to long (12c) so as to increase the throw of the discharged swirl air stream from short (8a) through medium (8b) to long (8c) , respectively.

Sub-Figures i-a and i-b, ii-a and ii-b, and iii-a and iii-b show nozzle discharge direction actuator (Al) mechanically linked to nozzle guide vanes (He, Hf and Hg) angled largely up, horizontal and largely down, respectively, thereby directing the discharge angle of pilot jet (12a, 12b and 12c) largely up, horizontal and largely down to in turn direct the discharged swirl air stream (8a, 8b and 8c) largely up, horizontal and largely down.

Sub-Figures i-a and i-b, ii-a and ii-b, and iii-a and iii-b show annular damper actuator A2 mechanically linked to adjustable annular dampers shown largely closed, partly open and fully open (17k, 171 and 17m, respectively) providing low, medium and high open areas upstream of swirl vanes (16) to, at a largely constant operating pressure of variable volume supply air stream (14) , increase the discharged swirl airflow rate from low, through medium, to high. Not shown in the illustrations referred to above, for reasons of simplicity, are embodiments of the invention in which in addition to the horizontal nozzle guide vanes that may be angled up and down (lie and llg) , vertical guide vanes that may be angled left and right are

included, located either directly upstream or directly downstream of the horizontal guide vanes, to deflect the discharged pilot jet left and right.

Advantageous Features of the Embodiments Described Herein

An air delivery system incorporating the diffuser described herein provides the potential for substantial energy savings and more effective performance, as well as for improved thermal comfort, reduced capital cost and enhanced aesthetics.

HVAC systems that deliver supply air to spaces via side-blow swirl diffusers in accordance with side-blow embodiments of the invention may be designed to operate with variable speed drive fans or incorporate devices, such as variable air volume (VAV) boxes, to reduce air flow during periods of low thermal load, thereby saving fan energy, as a diffuser as described by these

embodiments of the invention maintains largely constant throw over a wide range of varying airflow rates supplied to the diffuser at largely constant pressure, unlike side-blow swirl diffusers of the prior art. Moreover, both for side-blow and for ceiling swirl diffusers as described by certain embodiments of the invention, HVAC system airflow may be reduced during periods of low

heating demand, saving fan energy, or during pre-occupancy heating, thereby allowing return air ducts and dampers to be sized for less than 100% airflow and allowing energy- savings to be achieved during the warm-up phase of the space.

In comparison to prior art diffusers of largely equal airflow duty and throw, side-blow swirl diffusers with adjustable discharge direction, as described herein, are more compact and have a larger swivel arc of discharge direction adjustment, providing a greater degree of

direction adjustability to improve both cooling and

heating performance from a smaller diffuser assembly.

Moreover, such diffusers can be flush mounted to the surface that they discharge from, such as a wall or duct. This is not possible with prior art diffusers, which are bulky and protrude from surfaces. Additionally, prior art side-blow swirl diffusers with swivel adjustment generally suffer from a visible lack of alignment between the

discharge angles of diffusers in a row, causing an eyesore that is often unavoidable due swivel actuator hysteresis.

Optional actuators, for altering discharge direction, are hidden from view in the embodiments described herein, whereas they are visible with the prior art diffusers.

Additionally, due to the low bulk and substantially

reduced frictional resistance of the components comprising the swivel mechanism in the invention, as well as the elimination of the bellows air seal used in the prior art, such actuators in the invention may be thermally powered and regulated by supply air temperature alone, without the need for an external power or control source .

In other words, the design of the diffuser is such that only the direction of the nozzle is changed rather than that of the entire (and substantially heavier)

diffuser. This results in reduced swivel axis friction. Moreover, the elimination of the bellows seal also contributes to the reduction in friction, as deformation of the bellows in the prior art (due to the need for a large seal between the swivelling diffuser and mounting flange) substantially increases resistance.

The ability, in certain embodiments of the invention, to set or adjust both the diffuser throw and the volume flow rate of the side-blow and ceiling swirl diffusers permits a constant diffuser size to be used for a variety of airflow rates and throws, thereby requiring a smaller variety of diffuser sizes to be manufactured, reducing manufacturing costs, and allowing constant diffuser face sizes to be used to provide a uniform aesthetic in

applications where diffuser airflow duties and throws vary. Such advantages are not possible with comparable swirl diffusers of the prior art.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. An air diffuser comprising a body, at least one swirl pattern discharge element and at least one jet pattern discharge element, wherein the jet pattern discharge element is manipulable to vary the airflow direction angle of a discharged jet pattern of air relative to an axis perpendicular to a discharge face of the swirl pattern discharge element to thereby alter the angle of the air discharged from the swirl pattern discharge element.

2. An air diffuser in accordance with Claim 1, wherein the body is substantially cylindrical in shape.

3. An air diffuser in accordance with any one of

Claims 1 or 2 , wherein the swirl pattern discharge element includes a plurality of radial vanes arranged to discharge a swirl pattern of air.

4. An air diffuser in accordance with any one of

Claims 1 to 3 , wherein the jet pattern discharge element includes a nozzle arranged to discharge a jet pattern of air.

5. An air diffuser in accordance with Claim 4, wherein the nozzle discharge direction is adjustable relative to an axis perpendicular to the discharge face of the

diffuser.

6. An air diffuser in accordance with Claim 4, wherein the volume flow rate of the jet pattern discharge element is adjusted by a damper located at least partly within the nozzle .

7. An air diffuser in accordance with any one of

Claims 4 to 6, wherein, on application of a largely- constant pressure of air to the diffuser, adjustment of the nozzle damper alters the diffuser axial throw of the combined jet pattern and swirl pattern of discharged air relative to the plane of the swirl diffuser discharge face .

8. An air diffuser in accordance with any one of the preceding claims, wherein adjustment of at least one of the diffuser discharge direction, axial throw and volume flow rate is performed by at least one actuator.

9. An air diffuser in accordance with Claim 8, wherein the operation of the diffuser is performed by actuator driven manipulation of at least one of the elements.

10. An air diffuser in accordance with Claim 9, wherein manipulation of at least one element is performed by at least one actuator that is powered and regulated by supply air temperature or pressure alone.

11. An air diffuser in accordance with any one of

Claims 7 to 10 when dependent on Claim 3, wherein the volume flow rate of the swirl discharge pattern is adjustable or may be preset by a damper upstream of, or integrated into, the radial vanes.

12. An air diffuser in accordance with Claim 11, wherein on the application of a largely constant volume flow rate of air to the diffuser, adjustment of the swirl discharge pattern volume flow rate changes the supply air pressure to the diffuser thereby changing the discharge velocity of the nozzle, in turn altering the diffuser axial throw of the combined jet pattern and swirl pattern of discharged air relative to the plane of the swirl diffuser discharge face .

13. An air diffuser assembly for use in combination with a wall, bulkhead, ceiling or floor air delivery system comprising an air diffuser in accordance with any one of Claims 1 to 12 and at least one mounting device arranged to connect the air diffuser to the wall, bulkhead, ceiling and/or floor.

14. An air diffuser including a body, at least one swirl discharge pattern element and at least one jet discharge pattern element, wherein, on the application of a largely constant air supply pressure, the diffuser maintains a largely constant axial throw of the combined jet and swirl patterns of discharged air along an axis perpendicular to the plane of the swirl diffuser discharge face as the diffuser supply airflow rate is varied.

15. An air diffuser in accordance with Claim 14, further including the features of any one of Claims 1 to 12.

16. An air diffuser assembly in accordance with Claim 13, further including the features of Claim 14.

17. An air diffuser comprising a body, at least one swirl discharge pattern element and at least one jet discharge pattern element arranged to be manipulated to alter a diffuser axial throw discharge direction and volume flow rate .

18. An air diffuser in accordance with Claim 17 further comprising at least one horizontal nozzle guide vane.

19. An air diffuser in accordance with Claims 17 or 18 further comprising a vertical nozzle guide vane.