AU2007283461B2

AU2007283461B2 - Duct adaptor

Info

Publication number: AU2007283461B2
Application number: AU2007283461A
Authority: AU
Inventors: Michael William Sterling
Original assignee: Westaflex Australia Pty Ltd
Current assignee: Westaflex Australia Pty Ltd
Priority date: 2006-08-11
Filing date: 2007-08-10
Publication date: 2011-09-01
Anticipated expiration: 2027-08-10
Also published as: WO2008017124A1; AU2007283461A1

Abstract

A duct adaptor for coupling between a diffuser frame assembly and an air conditioning/heating duct, the duct adaptor having a first wall portion which, in use, is coupled to the diffuser frame and a second wall portion which, in use, is located within an end of the duct; and a plurality of baffles mounted within the wall portion, the baffles being biased into a closed position in which flow of air through the duct adaptor is substantially prevented, the baffles being arranged, in use, to move into an open position when a predetermined flow rate of air flows from the duct to be discharged through the diffuser frame.

Description

C:\NRPorblDCC\DERU685499_.DOC-2E2DlI DUCT ADAPTOR This invention relates to a duct adaptor and frame assembly incorporating the adaptor. 5 In air conditioning systems, it is customary to have diffusers mounted in ceiling panels to which air conditioning ducts are connected. Chilled air flows from an air conditioning unit through ducts and is discharged into the room through the diffusers. Typically, the diffusers are in the form of a frame which may have a number of adjustable 10 baffles therein to direct flows of air to required parts of the space to be air conditioned. In many domestic systems, heating is independently provided to the room, i.e. not through the air conditioning ducts. If the ducts are open, heated air, which tends to rise by convection to the ceiling, can be lost through the air conditioning ducts. 15 It is an object of the present invention to provide a duct adaptor and diffuser frame assembly which prevent backflow of air therethrough to thereby avoid heat losses. According to the present invention there is provided a duct adaptor for coupling 20 between a diffuser frame and an air conditioning/heating duct, the duct adaptor including a wall portion which, in use, is mounted within an end of the duct and permits air flowing in the duct to pass therethrough to the diffuser frame, the duct adaptor further including a plurality of baffles each mounted for rotation about an axis between a closed position and an open position and wherein, when the baffles are in their respective closed positions, 25 they span said wall portion and substantially prevent flow of air through the duct adaptor, each of the baffles being biased into its closed position, and wherein, when the pressure of air within the duct exceeds a predetermined level, the baffles will be rotated in a first sense under the influence of pressure of air in the duct to their respective open positions and stop means to limit rotation of the baffles in a second sense, opposite to the first sense, to their 30 respective closed positions when the pressure of air within the duct falls below said predetermined level to thereby prevent backflow of air through the duct adaptor into the duct.

C:WRPortbMDCCDER\685499_I.DOC2 72II -2 The invention also provides a diffuser assembly including: a diffuser frame having a flange which in use overlies a ceiling or wall panel having an opening therein, the diffuser frame including upstanding walls which in use project through the opening; and 5 a duct adaptor as defined above. Preferably the baffles are mounted for pivotal rotation relative to the second wall portion of the duct adaptor. 10 Preferably further, the baffles are biased by gravity to closed positions. Preferably the assembly includes mounting brackets which are interlocked onto the wall portion of the duct adaptor, the brackets including hinge formations which cooperate with complementary formations on the baffles to thereby enable the pivotal rotation of the 15 baffles relative to the wall portion of the duct adaptor. Preferably the hinge formations include recesses and the complementary formations of the baffles include pins. 20 Preferably further, there are four of said baffles each having perpendicular inner edges and wherein in the closed position thereof said inner edges lie on lines which are perpendicular to one another to thereby effectively prevent, in use, air flowing through the duct. 25 Preferably further, each baffle has an outer edge which is shaped to be complementary to an adjacent edge of the wall portion of the duct adaptor when in their closed positions. Preferably further, the wall portion of the duct adaptor is cylindrical and the outer 30 edges of the baffles are arcuate.

WO 2008/017124 PCT/AU2007/001125 -3 Preferably the baffles are pivotal about respective axes which lie on a square. Preferably further, the brackets include stop formations which engage the baffles in their closed positions to thereby define the closed positions thereof. 5 Preferably further, the baffles include weights which bias the baffles to their closed positions. Preferably the weights are formed by integral projecting fins which also serve, in 10 use, to direct air flow through the diffuser frame. Preferably further, the baffles include deflecting surfaces which, in use, in the open positions of the baffles, deflect part of the air flowing through the diffuser frame laterally relative to the duct adaptor. 15 Preferably further, the ridges project, from the deflecting surfaces. Preferably further, the diffuser frame, duct adaptor, baffles and brackets are injection moulded from plastics materials. Preferably further, the plastic material is high 20 impact polystyrene or A.B.S. The invention will now be further described with reference to the accompanying drawings, in which: Figure 1 is a schematic view of an air conditioning system incorporating a duct 25 adaptor of the invention; Figure 2 shows the system when the air conditioning unit is operating; Figure 3 is a schematic cross-sectional view showing more details of the diffuser frame assembly; Figure 4 is a perspective view from above of a duct adaptor in a closed position 30 constructed in accordance with the invention; Figure 5 is a side view of the assembly; WO 2008/017124 PCT/AU2007/001125 -4 Figure 6 is a plan view of the assembly in a closed position; Figure 7 is a schematic cross-sectional view along the line 7-7; Figure 8 is a more detailed fragmentary view of part of the assembly; Figure 9 is another more detailed view of part of the assembly; 5 Figure 10 is a fragmentary underside view of the assembly in its closed position; Figure 11 is a perspective view from above of the assembly in an open position; Figure 12 is a side view of the assembly in an open position; Figure 13 is a plan view of the assembly in the open position; Figure 14 is a cross-sectional view along the line 14-14; 10 Figure 15 is a more detailed fragmentary view of part of the assembly; Figure 16 is a fragmentary view of part of the assembly viewed from below in an open position; Figures 17 and 18 are exploded views of the assembly; and Figure 19 is a simplified view of the diffuser frame; 15 Figure 20 is an underside view of one of the baffles of the duct adaptor; Figure 21 is a plan view of the baffle; Figure 22 is a perspective underside view of the baffle; Figure 23 is a perspective view from the top side of the baffle; Figure 24 is a rear view of the baffle; 20 Figure 25 is a side view of the baffle; Figure 26 is a different side view of the baffle; Figure 27 is a cross-sectional view along the line 27-27; Figure 28 is a top perspective view of the bracket; Figure 29 is a bottom perspective view of the bracket; 25 Figure 30 is a side view of the bracket; Figure 31 is a cross-sectional view along the line 31-31; Figure 32 is a rear view of the bracket; Figure 33 is a plan view of the bracket; Figure 34 is a frontal view of the bracket; 30 Figure 35 is a view of the bracket axially from one of its hinge socket; and Figure 36 is a more detailed fragmentary side view.

C:\NRPortbl\DCCDERU685499_.DOC.2807/2011 -5 Figure 1 schematically shows an evaporative air conditioning system 1 utilising a diffuser frame assembly 3. The air conditioning system 1 includes an evaporative air conditioning unit 5 which is normally mounted on a support structure (not shown) on the exterior of a roof 7 of a building such as a domestic house. A duct 9 extends from the unit 5 5 and is coupled to a duct adaptor 6 constructed in accordance with the invention. The duct adaptor 6 includes a baffle assembly 8 which is closed as shown schematically in Figure 1 when the air conditioning unit 5 is not operating. When, however, the air conditioning unit is operating, the flow of air in the duct 9 causes the baffle assembly 8 to open, thereby permitting flow of chilled air through the diffuser frame assembly 3 into the 10 room to be air conditioned, as indicated by arrow 11, which is parallel to the axial direction of the duct, as shown in Figure 2. The diffuser frame assembly is similar to that disclosed in Australian Patent Application No. 2006200657 and the content of that specification is incorporated herein by cross-reference. The diffuser frame assembly includes a reverse flow passageway 13 which permits a reverse flow of air through the diffuser frame 15 assembly into the ceiling space, as indicated by arrows 15 in Figure 2. This enables the evaporative air conditioning system I to be used when all of the doors and windows of the rooms to be air conditioned are closed. When the air conditioning unit 5 is not operating, and the baffle assembly 8 is closed, as shown in Figure 1, the diffuser frame assembly 3 includes baffles 17 which also close, as diagrammatically shown in Figure 3. This 20 prevents reverse flows of air through the duct adaptor and reverse passageway 13 thereby avoiding heat losses. Some components have been omitted in Figures 1 and 2 for clarity of illustration. Figure 3 schematically shows the diffuser frame assembly 3 in more detail. The 25 assembly 3 includes a first frame 19 and second frame 21. The first frame 19 and the second frame 21 can be injection moulded from plastics material, in the usual way. The first frame 19 can be of known type having upstanding sidewalls 23 and laterally projecting flanges 25. The second frame 21 interlocks with the flanges 25 of the first frame and defines the reverse flow passageway 13 between the two frames. The second 30 frame 21 overlies the ceiling 27, as shown in Figure 3, so as to provide a neat finish.

WO 2008/017124 PCT/AU2007/001125 -6 Figures 4 to 9 illustrate in more detail the duct adaptor of the invention in a closed position coupled to the diffuser frame assembly 3. The diffuser frame assembly 3 is shown in more detail in Figure 19. As schematically shown in Figure 3, a square opening is cut into the ceiling 27, the opening being somewhat larger than the sidewalls 23 of the diffuser 5 frame assembly 3 but smaller than the second frame 21. In this way the second frame 21 of the diffuser frame assembly overlies the adjacent part of the ceiling so as to provide a neat finish. Clips (not shown) can be used to fix the diffuser frame assembly to the ceiling in the usual way. The first frame 19 includes an opening 14 which is spanned by cross bars 16. A set of baffles (which are sometimes referred to as biscuits) can then be located 10 in the diffuser frame assembly 3 and supported by flanges formed on the cross bars 16 and the inner edges of a flange portion 10 of the frame. The orientation of the baffles can be changed so as to direct airflows from the diffuser frame into different parts of the room to which cooled air is supplied. Normally the first frame 19 is square and is sized to accommodate ducts 9 with which it is used. Typically the ducts 9 are 250, 300, 350, 400 15 and 450mm in diameter. Sometimes, however, rectangular diffuser frames can be provided. The frame 19 is generally of a shape which is known in the art and full details of it therefore need not be described. It does, however, include projections 18 on the upper part of the wall portion 12, the projections 18 being for interlocking with slots provided on the duct adaptor 6, as shown in Figure 19. 20 The duct adaptor 6 includes a square plate portion 20, upstanding frustoconical sidewall 22 and a central circular opening 24. The plate portion 20 includes downwardly extending flanges 26, 28, 30 and 32 along its side edges. The plate portion 20 also includes slots 34 adjacent to the side edges of the plate portion 20 for interlocking with the 25 projections 18 moulded on the top of the sidewall 23. The outer surface of the sidewall 22 is moulded with diametrically opposed pairs of ridges 36 which are for the purpose of supporting the baffle assembly 8, as will be described in more detail below. The sidewall 22 is frustoconical so that after injection moulding of the duct adaptors 6, they can be stacked with their sidewall portions nested for compact storage and transport. 30 WO 2008/017124 PCT/AU2007/001125 -7 As shown in Figures 4 to 7, duct adaptor 6 is in use interlocked onto the first frame 19. More particularly, the side edges of the plate portion 20 of the duct adaptor overlie the top edge of the sidewall 23 of the first frame 19 as shown in Figure 3. The projections 18 of the diffuser frame are received within the slots 34 of the duct adaptor. The flanges 26, 5 28, 30 and 32 overlie the upper parts of the sidewalls 23 so as to interlock the components together and form a seal (or near seal) between the plate portion 20 and the sidewalls 23. In use a duct 9 is connected to the sidewall 22 so that air flowing through the duct can pass through the opening 24 and then through the opening 14 in the first frame 19 into the room to be air conditioned. 10 The baffle assembly 8 includes four baffles 40, 42, 44 and 46, as best seen in Figure 10. The baffles 40, 42, 44 and 46 are mounted for pivotal movement about axes 48, 50, 52 and 54 respectively, the axes 48, 50, 52 and 54 lying on sides of a square. The baffle assembly 8 further includes four mounting brackets 56, 58, 60 and 62 which mount 15 the baffles to the duct adaptor 6 and form the pivotal connections for rotation thereof. The mounting brackets are all the same shape and the structure of the mounting bracket 58 will be described in more detail with reference to Figures 28 to 36. The mounting bracket 58 includes a central body portion 64 from which extend lateral wings 20 66 and 68. The central body portion 64 includes a recess 70 which includes a sawtooth formation 72, the sawtooth formation 72 being complementary in shape to the ridges 36 of the duct adaptor so as to interlock therewith. The inner edges 71 and 73 of the wing portions 66 and 68 are circular so as to snugly engage the inner surface of the sidewalls 23 of the duct adaptor 6. In this way the mounting bracket 56 (and the other mounting 25 brackets) can be snap fitted onto the sidewalls 23 so as to be securely mounted on the duct adaptor 6. As best seen in Figure 8, the upper edge 67 of the sidewall 22 includes slots 69 which receive the central body portion 64 of the bracket so that the bracket does not project above the level of the upper edge 67 of the sidewall of the duct adaptor. 30 The mounting bracket 58 includes a first pair of hinge formations 74, 75 which are opposed to one another and axially spaced so as to define an open socket 77 for receipt of a WO 2008/017124 PCT/AU2007/001125 hinge pin 78 integrally formed on the baffle 42 as shown in Figure 9. The socket 77 has an axis 79 as shown in Figures 33 and 35 which in use is concentric with the axis 50. Figure 35 is an axial view looking into the socket 77. The mounting bracket 58 includes a second pair of hinge formations 80, 81 which define an open socket 83, the axis 124 of which is 5 concentric with the axis 52. The socket 83 receives, in use, a hinge pin 82 integrally formed on the baffle 44. Each of the baffles is also provided with a hinge pin on the other side thereof so that the two hinge pins of each baffle can be received within the hinge formations of the mounting brackets to thereby enable the baffles to pivot about the axes 48, 50, 52 and 54, as described in more detail below. 10 The wings 66 and 68 of the mounting brackets include stop formations 92 and 94 which in use engage the upper surfaces of the edges of the baffles so as to limit rotation thereof and thereby define the closed positions of the baffles as described below. 15 Figures 20 to 27 show the baffle 42 in more detail. The other baffles 40, 44 and 46 are of similar shape and need not be separately described. It will be seen that the baffle 42 is generally of a segment shape having a planar portion 85 and two inner edges 87 and 89 which are perpendicular to one another. The baffle includes an outer edge 98 which is of circular shape and is of complementary shape to the inner surface of the sidewalls 23 of the 20 duct adaptor 6. The baffle 42 includes the hinge pin 78 on one side thereof and a second hinge pin 91 on the opposite side, these pins being concentric with the axis 50, as indicated on Figure 20. The baffle 42 includes a downwardly curved peripheral portion 93, as best shown in Figures 22 and 25. The baffle 42 is moulded with five fins 90 which project downwardly from the peripheral portion 93. The planes of the fins 90 are perpendicular to 25 the axis 50, as shown in Figures 20 and 24. The fins 90 provide additional weight so that when the air conditioning unit 5 is not operating, the weight of the fins 90 biases the baffle 42 in an anti-clockwise direction (as seen in Figure 27) against the stop formations 92 and 94 which form part of each of the mounting brackets. More particularly the baffle 42 is formed with lateral tabs 120 and 122 located between the ends of the curved peripheral 30 portion 93 and the hinge pins 78 and 91, as shown in Figure 20. The tabs 120 and 122 engage the formations 92 and 94 when the air conditioning unit 5 is not operating. This WO 2008/017124 PCT/AU2007/001125 -9 ensures that all of the baffles 40, 42, 44 and 46 of the baffle assembly are held in closed positions when the unit 5 is not operating. Figures 3 to 10 show the baffles in their closed positions in which their respective 5 inner edges engage or substantially engage each other so as to effectively close the airflow path through the duct adaptor 6. More particularly, each of the baffles 40, 42, 44 and 46 include a circular outer edge 96, 98, 100 and 102 of complementary shape to the inner surface of the sidewalls 23 of the duct adaptor. In this way the outer edges of the baffles engage or lie closely adjacent to the inner surface of the sidewalls 23 so as to effectively 10 prevent airflow between the edges of the baffles and the sidewalls 23. It is preferred that all of the baffles are in a balanced position or a near balanced position so that, when there is a positive airflow through the duct (i.e. in the direction of arrow 11) to which the assembly is connected, the pressure of the air will cause pivotal 15 rotation of the baffles 40, 42, 44 and 46 so that they will move to their open positions, as diagrammatically illustrated in Figures 8 to 13. In the fully open position of the baffle assembly 8, the baffles 40, 42, 44 and 46 are located in generally vertical orientations so as to minimise obstruction to airflow through the diffuser frame assembly. Also, the fins 90 serve to direct the flow of air axially through the assembly. 20 It has been found that the provision of the curved peripheral portions 93 on the baffles reduces noise generated by air flowing over the baffles. The curved peripheral portion 93 also tends to minimise vibration of the baffles caused by the air flowing over them. 25 When the air conditioning system turns off and/or the positive air pressure within the duct falls below a predetermined level, the baffles 40, 42, 44 and 46 will return to their closed positions. It will be appreciated that in the closed positions, reverse airflow through the diffuser assembly is prevented. This prevents heat losses through the ducting which 30 might otherwise be caused if the ducts were not closed. Nonnally, warm air rising by convection towards the diffuser frame assembly 3 would not exert sufficient pressure on C:\NRPonbhDCCDER\68549I_.DOC.2L/07/2011 -10 the baffles to open them. In any event, any rising air would tend to move the baffles towards their closed positions so as to thereby prevent heat losses by reverse airflow through the diffuser frame assembly 3. 5 In the preferred form of the invention, the diffuser frame assembly 3, duct adaptor 6, baffles 40, 42, 44 and 46, and mounting brackets 56, 58, 60 and 62 are injection moulded from plastics material. A variety of plastics materials could be used but it is preferred that the material is high impact polystyrene. 10 Many modifications will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an 15 acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Claims

1. A duct adaptor for coupling between a diffuser frame and an air conditioning/heating duct, the duct adaptor including a wall portion which, in use, is 5 mounted within an end of the duct and permits air flowing in the duct to pass therethrough to the diffuser frame, the duct adaptor further including a plurality of baffles each mounted for rotation about an axis between a closed position and an open position and wherein, when the baffles are in their respective closed positions, they span said wall portion and substantially prevent flow of air through the duct adaptor, each of the baffles being biased 10 into its closed position, and wherein, when the pressure of air within the duct exceeds a predetermined level, the baffles will be rotated in a first sense under the influence of pressure of air in the duct to their respective open positions and stop means to limit rotation of the baffles in a second sense, opposite to the first sense, to their respective closed positions when the pressure of air within the duct falls below said predetermined 15 level to thereby prevent backflow of air through the duct adaptor into the duct.

2. An adaptor as claimed in claim I wherein each of the baffles is biased into its closed position by gravity. 20

3. An adaptor as claimed in claim I or 2 including mounting brackets which are interlocked onto the wall portion of the duct adaptor, the brackets including hinge formations which cooperate with complementary formations on the baffles to thereby enable the pivotal rotation of the baffles relative to the wall portion of the duct adaptor. 25

4. An adaptor as claimed in claim 3 wherein the stop means include stop formations on said mounting brackets said stop formations being engagable with the baffles.

5. An adaptor as claimed in claim 3 or 4 wherein the hinge formations include recesses and the complementary formations of the baffles include pins. 30 C:\NRortbNDCC\DER685499_-.DOC.207/2011 -12

6. An adaptor as claimed in any one of claims 1 to 5 wherein there are four of said baffles each having perpendicular inner edges and wherein in the closed position thereof said inner edges lie on lines which are perpendicular to one another to thereby effectively prevent, in use, air flowing through the duct. 5

7. An adaptor as claimed in any preceding claim wherein each baffle has an outer edge which is shaped to be complementary to an adjacent edge of the wall portion of the duct adaptor when in their closed positions. 10

8. An adaptor as claimed in any preceding claim wherein the wall portion of the duct adaptor is cylindrical and the outer edges of the baffles are arcuate.

9. An adaptor as claimed in any preceding claim wherein the respective axes of the baffles lie on a square. 15

10. An adaptor as claimed in any preceding claim wherein the stop means are located on the brackets.

11. An adaptor as claimed in any preceding claim wherein the baffles are weighted 20 such that they are biased towards their closed positions.

12. An adaptor as claimed in claim 11 wherein the baffles include integral projecting fins which also serve, in use, to direct air flow through the diffuser frame. 25

13. An adaptor as claimed in any preceding claim wherein the baffles include deflecting surfaces which, in use, in the open positions of the baffles, deflect part of the air flowing through the diffuser frame laterally relative to the duct adaptor.

14. An adaptor as claimed in claim 13 wherein the deflecting surfaces are curved. 30 C:\V4RortbDCC\DERU63499_.DOC-2D7/2011 - 13

15. An adaptor as claimed in claim 14 wherein the deflecting surfaces include convex sides and concave sides and wherein the convex sides are disposed towards said second wall portion when the baffles are in their open positions. 5

16. An adaptor as claimed in any preceding claim wherein the baffles include fins.

17. An adaptor as claimed in claim 16 wherein the fins lie in planes which are generally parallel to the flow of air through the wall portion when the baffles are in their open positions. 10

18. A diffuser assembly including: a diffuser frame having a flange which in use overlies a ceiling or wall panel having an opening therein, the diffuser frame including upstanding walls which in use project through the opening; and 15 a duct adaptor as claimed in any one of claims 1 to 17.

19. A duct adaptor substantially as hereinbefore described with reference to the accompanying drawings.