Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT (ORIGINAL) Name of Applicant: Westaflex (Australia) Pty. Ltd. of 140-152 Bamfield Road, Heidelberg West, Victoria, 3081, Australia Actual Inventor: STERLING, Michael William Address for Service: DAVIES COLLISON CAVE, Patent Attorneys, 1 Nicholson Street, Melbourne, 3000, Victoria, Australia Invention Title: "Improved diffuser" The following statement is a full description of this invention, including the best method of performing it known to us: Q\OPER\GCP\200PAI 272720 04.doc - 1/t06 P:OErGCl127272Gn pv.deC.7$A IMPROVED DIFFUSER This invention relates to a diffuser, 5 More particularly, the invention relates to a diffuser which can be used in an air conditioning or ventilation system for a room. Air conditioning or ventilation systems normally have a diffuser located in the ceiling or wall of a room to which an air conditioning or ventilation duct is connected. The 10 diffuser normally includes a diffuser frame which has a flange which overlies the ceiling or wall so as to cover the opening fonned therein for receipt of the frame. The flange is normally integrally formed with parts which form a connector to which a duct or duct adaptor can be connected so that air can flow to or from the room through the diffuser. 15 In air conditioning or ventilation systems where there is a high volume of air flow through the diffuser, some provision needs to be made for return air flows. Return air flow can be a particular problem with evaporative air conditioning systems which tend to have a very high flow rate of air therethrough. The flow rate is such that the evaporative air conditioners can nonnally only be operated when a window or door in the room is open 20 otherwise the lack of a suitable return or exhaust path for the air inhibits air flow through the evaporative air conditioner. In a domestic air conditioning system, this causes problems because the system cannot be operated unless a door or window is open. This represents a lack of security for the dwelling where the air conditioning system is installed. This has the consequence that in many situations the evaporative air conditioning system 25 cannot be activated unless the occupier of the dwelling is present. This has a substantial disadvantage because of the lead time required for cooling the dwelling to the desired temperatures. For analogous reasons, it is problematic to arrange for evaporative air conditioners to work on time cycles because of the need to ensure that windows or doors are open in order for correct air flows to be established. 30 P:WER\Cniz2772 prov.daea7POA4 -2 Australian Patent Application 2005203780 discloses a diffuser which provides for a return air flow path and the content of that specification is incorporated herein by cross reference. 5 The object of the present invention is to provide improvements in the diffuser disclosed in the aforementioned patent application. The object of the present invention is to provide a diffuser for an air conditioning or ventilation system which has provision for reverse air flows therethrough. 10 According to a first aspect of the present invention there is provided a diffuser assembly for an air conditioning or ventilation system, the assembly including: a first diffuser frame having first walls which define a connector to which a duct or duct adaptor can be connected and a first flange means which extends laterally relative to the first walls; 15 and.a second diffuser frame having an outer portion which in use overlies a ceiling or wall panel adjacent to an opening therein to accommodate the diffuser assembly and an inner portion which in use co-operates with the first flange means of the first diffuser frame to define a reverse flow passageway into the opening, and wherein the second diffuser frame includes a plurality of vanes pivotally connected to the inner portion, the vanes being 20 biased by gravity to a closed position in which flow is restricted through said reverse flow passageway and limiting means which serve to limit rotation of the vanes in directions away from said first walls. The provision of the limiting means prevents the vanes from moving to positions in 25 which they cannot return under gravity to their closed positions. The invention also provides a diffuser frame for use with a known diffuser frame to define a diffuser frame assembly, the known diffuser frame having first walls which define a connector to which a duct or duct adaptor can be connected and a first flange means 30 which extends laterally relative to the first walls, the diffuser frame having an outer portion which in use overlies a ceiling or wall panel adjacent to an opening therein to C:\NRPonbl\DCC\DER\3672289j..DOC-19/fl2U I -3 accommodate the diffuser frame assembly and an inner portion which in use co-operates with the first flange means of the diffuser frame to define a reverse flow passageway into the opening, and wherein the diffuser frame includes a plurality of vanes pivotally connected to the inner portion, the vanes being biased by gravity to a closed position in 5 which flow is restricted through said reverse flow passageway and limiting means which serve to limit rotation of the vanes in directions away from said first walls.
PADPsOCIn27272op6rc.dewI7sdU -4 Preferably, the locating projections comprise ribs. Normally two ribs would be provided on each flange which makes up the second diffuser frame and these locating ribs co-operate with the opening in the panel to accurately locate the diffuser assembly relative 5 to the opening. This facilitates installation of the assembly. Preferred embodiments of the present invention are hereinafter described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic view of an evaporative air conditioning system 10 incorporating a diffuser frame in accordance with a preferred embodiment of the present invention; Figure 2 is a schematic view of components of the diffuser frame; Figure 3 is a simplified perspective view of a reverse flow frame of the diffuser frame; 15 Figure 4 is a perspective view of a pressure relief frame of the diffuser frame; and Figure 5 is a schematic cross-sectional view showing the way in which the frame operates. Figure 1 schematically shows an evaporative air conditioning system 2 utilising a 20 diffuser frame assembly 4. The air conditioning system 2 includes an evaporative air conditioning unit 6 which is normally mounted on a support structure (not shown) on the exterior of a roof 8 of a building such as a domestic house. A duct 10 extends from the unit 6 and is coupled to a valve unit 12 which is arranged to open when the air conditioning unit is operating but to close when the unit 6 is not operating. The valve unit 25 12 can be of the type shown in US Patent Nos. 5,201,685, 5,277,658, 6,685,557 or Australian Patent Application No. 200157738. Briefly, the valve unit 12 includes vanes 14 which are normally biased to a closed position, as shown in broken lines, by gravity, springs or the like. When, however, the unit 6 is operating, the pressure of the air flow is such that the air flow causes the vanes to move to an open position, as shown in Figure 1. 30 Means (not shown) may be provided to control the extent to which the vanes 14 open to thereby regulate air flow to various diffusers which may be coupled to the unit 6. In use, C:\NRPotbl\DCC\DER\3672289_l.DOC-I909f/20f1 -5 chilled air from the unit 6 passes through the duct 10, and valve unit 12 and passes through the diffuser assembly 4 and into the room to be cooled. In the illustrated arrangement, the diffuser 4 is mounted in an opening 16 in a ceiling panel 18 of the room to be chilled. Normally the diffuser assembly 4 includes removable baffles (not shown) which can be 5 adjustably oriented so as to direct the flow of the chilled air in preferred directions. Such baffles are well known and need not be described. As the unit 6 has a high air flow, normally the space into which the chilled air flows needs to be ventilated. In accordance with a preferred embodiment of the invention 10 however the diffuser frame assembly provides for reverse flow, as will be explained in more detail below. The assembly for thus means that the evaporative air conditioning unit 6 can be operated even though all doors and windows in the space to which chilled air is supplied can be closed. Accordingly the assembly 4 provides for improved security of the building. 15 Figure 2 is an exploded view which schematically shows the diffuser assembly 4. The assembly includes a first frame 20 and second frame 22. The first frame 20 and the second frame 22 can be injection moulded from plastics material, in the usual way. The first frame 20 can be of known type having upstanding sidewalls 24 and a laterally 20 projecting flange 26. Normally this type of frame is fitted so that the sidewalls 24 extend through the opening 16 in the ceiling and the flanges 26 overlie the adjacent underside 19 of the ceiling 18 so as to form a neat finish. The sidewalls may include openings 28 through which mounting clips (not shown) can be passed so as to bear against the top surface 21 of the ceiling panel 18. This mounting arrangement is again well known and 25 need not be described in detail. In the diffuser assembly 4, the second frame 22 is located adjacent to the underside 19 of the ceiling surrounding the opening 16. The frame 22 includes laterally extending flanges 30, 32, 34 and 36 which are all of the same profile. Extending downwardly from 30 the flanges are spacing ribs 37. In use of the diffuser assembly 4, the sidewalls 24 of the first frame 20 pass through an opening 38 defined by the flanges 30, 32, 34 and 36 of the C:WRPonbr\DCC\DERu67228h9_.DOC- 9m9n II -6 second frame 22. The first frame 20 can be mounted to the ceiling 18 in the conventional way and this retains the second frame 22 clamped against the underside 19 of the ceiling. As shown in Figures 1 and 5, the ribs 37 hold the flanges 26 of the first frame 20 vertically spaced from the flanges of the second frame 22 thereby defining return air passageways 40 5 in the diffuser. In use of the diffuser assembly 4, when the air conditioning unit 6 is operating air flows into the room through the diffuser assembly 4, as indicated by arrow 42. Return air can pass through the passageways 40 into the roof space above the ceiling 18, as indicated by arrows 44. 10 Figure 3 is a simplified view of the second frame 22 which shows the preferred location of the ribs 37. In this drawing, vanes referred to below and mounting bosses therefore have been omitted for clarity of illustration. Figure 5 shows in more detail how the frames 20 and 22 cooperate. It will be seen 15 that in this embodiment, the flange 26 is curved and the lower edges 46 of the ribs 37 are curved so as to generally conform to the shape of the flange 26. The flange 32 is made up of a straight portion 48 from which the ribs 37 extend and an upwardly convex portion 50 which is shaped so as to define the passageway having a vertical height in the range from 6mm to 12mm. The passageway can extend the full length of the flanges of the frames. 20 Accordingly, the passageway may typically be 375mm long. The flange 32 terminates in a downwardly convex portion 54 having an outer edge 56. The outer edge 56 and the upwardly convex portion 50 would normally engage the underside 19 of the ceiling in use. The flanges 30, 34 and 36 are similar in profile to the flange 32 and the same reference numerals have been used to denote corresponding parts. 25 The second frame 22 (or the first frame 20) may be provided with valve elements or flaps which are normally closed but are opened when the unit 6 is operating. The valve elements or flaps are opened by the reverse flow through the passageways 40. 30 More particularly, the frame 22 includes two elongate vanes 82 and 83 which are mounted so as to be pivotally connected adjacent to the inner edge of the flange 36.
P 1PCI277120 paw.17AM6 -7 Similarly, the frame 22 includes two elongate vanes 84 and 85 which are mounted so as to be pivotally connected adjacent to the inner edge of the flange 34. The flanges 30 and 32 have similar vanes but these are segmented so as to define gaps 86, 88, 90 and 92 through which mounting clips (not shown) for the assembly can extend. More particularly, the 5 frame 22 includes two short end vanes 94 and 96 and a central vane 98. The vanes 94, 96 and 98 are pivotally connected adjacent to the inner edge of the flange 30. Similarly, the flange 32 includes short end vanes 100 and 102 and a central vane 104, the vanes 100, 102 and 104 being pivotally connected adjacent to the inner edge of the flange 32. Other vane configurations can be provided to suit diffusers having different numbers and/or locations 10 of mounting clips. As show in Figure 5, the frame 22 is formed with a plurality of upstanding mounting bosses 108 which are formed near the inner edges of the straight portions 48, as shown. The mounting bosses 108 include bores 110 which form pivotal connections with 15 hinge pins (not shown) formed on the ends of the vanes. In the diffuser frame assembly 4, the straight portions 48 of the flanges 32, 30, 34 and 36 include upstanding wall elements located adjacent to the vanes so as to limit the degree of rotation of the vanes away from the side walls 24 of the first diffuser frame 20. 20 In the illustrated arrangement, there are three wall elements, 121, 122 and 123 projecting upwardly from the flange 30. Similarly, the flange 32 is provided with a corresponding number of wall elements, but these are not visible in Figure 4. The flange 36 includes upstanding wall elements 123, 124, 125 and 126. Again the flange 34 is provided with a corresponding number of wall elements but these are not shown in Figure 4. The wall 25 elements 121, 122 and 123 are located outwardly adjacent to the vanes 94, 98 and 96 respectively. The pairs of vanes 123, 124, 125 and 126 are located outwardly adjacent to the vanes 82 and 83. Figure 5 shows in more detail the location of the wall element 122 relative to the 30 vane 98. It will be seen that the wall element 122 prevents the vane 98 from rotating to a position where it is generally parallel to the state portion 48 from where it would not be P: PERACiF 27272Od prno-d.1702thD able to return to its operative position, as will be described below. The other wall elements co-operate with the other vanes in a similar way. Vanes 82, 84, 94, 96, 98, 100, 102 and 104 are free to pivot about generally 5 horizontal axes. They are normally arranged so as to be biased under gravity so that the upper edges rest against the upstanding sidewalls 24 of the first frame 20, as shown in Figure 5. This corresponds to a position in which there is no air flow through the return air passages 40. At the corners of the frame 22, the side edges of the vanes are inclined so that they form mitre joints so as to minimise air flow through the corners when the air 10 conditioning unit 6 is not in operation. When, however, the unit 6 does operate, the internal pressure in the room will cause the vanes to disengage the sidewalls 24 of the first frame so as to permit return air to pass through the passageways 40 into the roof space above the ceiling 18, as required. The vanes also tend to prevent dust or foreign material from falling onto the flange 26 of the first frame from where they may inadvertently fall 15 into the room below. Typically all of the vanes are about 22mm wide (as measured in a generally vertical direction, in Figure 4). The diffuser assembly 4 also includes means for facilitating alignment of the diffuser frame assembly with the opening 16 in the sealing 18. In the illustrated 20 arrangement, this is achieved by having locating ribs 128 and 130 molded at respective ends of the flange 30. Similar ribs are formed on the flange 32, but these are not visible in Figure 4. Similarly, locating ribs 132 and 134 are molded at opposite ends of the flange 36. Again, the flange 34 is provided with similar ribs but these are not visible in Figure 4. 25 Figure 5 shows in more detail the rib 128 and the manner in which its co-operates with the hole 16 formed in the sealing panel 18. It will be seen that the rib 128 projects upwardly generally from the convex portion 50. The rib 128 includes a generally straight outer edge 136 which in use engages or lies adjacent to the opening 16 in the sealing panel 8. The rib 128 includes a convex curved edge 138 which tapers over the adjacent 30 part of the straight portion 48 of the flange, as shown.
PAtOERfi~CPUl720owdc..7n2b6 -9 Assuming that the installer cuts an opening 16 which is square or rectangular, it will be appreciated that the locating ribs will facilitate alignment of the diffuser frame assembly with the opening 16. 5 Many modifications will be apparent to those skilled in the art without departing frorn the spirit and scope of the invention. The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common 10 general knowledge in Australia.