This invention concerns an air transfer arrangement. Air transfer arrangements are often required to allow air flow between two areas. For instance such arrangements may be required to permit an air flow into an area beyond a room or otherwise which itself has natural ventilation. In such an instance an air transfer arrangement may be provided on an opposite wall of the room to for instance openable windows or other ventilation arrangements to allow air transfer to or from the area from the ventilation arrangements.

A problem with existing air transfer arrangements is that as well as transferring air, they can often transfer sounds or noise which is often undesirable.

According to the present invention there is provided an air transfer arrangement, the arrangement including an enclosure defining a passage with an inlet and an outlet, and a plurality of discrete sound absorbing structures extending across the passage.

At least three sound absorbing structures may be provided extending across the passage. The sound absorbing structures may be offset in the passage relative to each other. The sound absorbing structures may be offset longitudinally in the passage between the inlet and outlet, and may also be offset transversely.

Each sound absorbing structure may include first and second sound absorbing materials, with the materials having different sound absorbing properties to each other. The first sound absorbing material may be granular. The first sound absorbing material may be rubber which may be in chip form, or may be wood. The first sound absorbing material may be located centrally in the sound absorbing structures.

The second sound absorbing material may be fibrous, and may be any of mineral wool, wool, or cotton wool.

The sound absorbing structures may be shaped to reduce air resistance through the passage. The sound absorbing structures may have an oval cross section in plan profile, with the longest diameter of the oval aligned longitudinally in the passage.

The enclosure may be made of sound absorbing material, and may be made of acoustic board.

The enclosure may be made of a first part with a shallow substantially n shape cross section, and a second part mountable to the first part to extend between the free ends of the side limbs of the n.

At least part of the interior of the enclosure may be lined with a sound absorbing material, and may be lined with perforated metal sheet.

The arrangement may include a grille at the inlet and/or outlet, which grille may include a plurality of bars extending across the passage.

The arrangement may include a modulating damper, which damper may include a plurality of damper members extending across the passage.

The arrangement may include a fan for urging air through the passage, and the fan may include a housing mountable to one end of the enclosure. The arrangement may include an intumescent damper, which may be in the form of a grille of intumescent material mountable to one end of the enclosure Ducting may be provided, which ducting may permit the enclosure to be located above a ceiling.

Embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:-

Fig. 1 is a diagrammatic perspective view of a first air transfer arrangement according to the invention;

Fig. 2 is a diagrammatic exploded perspective view of the arrangement of Fig. 1 ;

Fig. 3 is a diagrammatic end view of the arrangement of Fig. 1 ;

Fig. 4 is a diagrammatic sectional plan view of the arrangement of Fig. 1 ;

Fig. 5 is a diagrammatic perspective view of a component of the arrangement of Fig. 1 ; Fig. 6 is a diagrammatic perspective exploded view of the component of Fig. 5;

Fig. 7 is a diagrammatic exploded perspective view of a second arrangement according to the invention;

Fig. 8 is a diagrammatic perspective view of components usable with arrangements according to the invention; Fig. 9 is a diagrammatic sectional plan view of a third arrangement according to the invention; Fig. 10 is a diagrammatic front view of the arrangement of Fig. 9;

Figs. 1 1 and 12 are similar views respectively to Figs. 9 and 10 but of a fourth arrangement according to the invention; Figs. 13 and 14 are similar views respectively to Figs. 9 and 10 but of a fifth arrangement according to the invention;

Figs. 15 and 16 are similar views respectively to Figs. 9 and 10 but of a sixth arrangement according to the invention; and

Figs. 17 and 18 are similar views respectively to Figs. 9 and 10 but of a seventh arrangement according to the invention.

Figs. 1 to 6 show a first air transfer arrangement 10 suitable for use for transferring air for instance between one room and another. Such an arrangement 10 could be provided on a wall on an opposite side of a room to an openable window, for providing air transfer into an adjacent room.

The arrangement 10 includes an enclosure 12 made up of a first part 14 of shallow n shape, and a second planar part 16 locatable between the free ends of the n of the first part 14 to provide an enclosure with a rectangular cross section. A sheet 18 of perforated galvanised steel is provided on the inside of the cross part of the second part 16, and on the other side of the first part 14.

Five sound absorbing structures 20 are provided extending between the first and second parts, and appropriate shaped and located openings 22 are provided in the second part 16 and sheets 18 to receive ends of the structures 20. The structures 20 are provided in a configuration as best shown in Fig. 4, with two rows of two, and a single central structure 20. As shown in Fig . 4, an upper pair of structures 20 are provided engaging against sides of the first part 14. A central structure 20 is provided whose centre is substantially aligned with the lowermost end of the two upper structures 20 shown in Fig. 4. The two lowermost structures 20 shown in Fig. 4 are transversely spaced between the two uppermost structures 20 and the central structure 20. The uppermost ends of the lowermost structures 20 are aligned substantially with the lowermost end of the central structure 20. This provides for different sized gaps between the respective structures 20, but even relatively small gaps when viewed from an end of the arrangement 10. Each of the structures 20 has a substantially oval shape in plan view, with the longest diameter parallel to the flow direction through the enclosure 12. The make up of the structures 20 is best illustrated in Fig. 6. Upper and lower end caps 24, 26 are provided, with a rod 28 extending therebetween with a lower nut 30 engageable on the end of the rod 28 to hold the structure 20 together.

Mounted around the rod 28 is an inner core 32 made up of recycled shredded rubber chip. The inner core 32 is located within a perforated metal housing 34. An outer core 36 is provided around the inner housing 34, and the outer core 36 is made up of a fibrous material such as mineral wool, wool or cotton wool. An outer housing 38 made of perforated galvanised steel is provided around the outer core 36.

As can be seen from Fig. 3, there is only a small amount of line of sight through the enclosure 12. In use the differing sound absorbing materials absorb different sounds. For instance, the inner core tends to absorb the lower frequency sounds. Whilst providing significant sound absorbing, the arrangement 10 permits a good air flow around the structures 20, and this is accentuated by the oval cross sectional shape of the structures 20.

Fig. 7 shows a second air transfer arrangement 40 with a number of additional components relative to the arrangement 10. To the left hand side as shown in fig. 7 of an enclosure 42 a fan 44 located within a housing 46 is provided, for drawing air through or pushing air through the enclosure 42. A modulating damper 48 is provided outside of the fan 44. The damper 48 comprises a plurality of damper members 50 extending across a frame 52. Outside of the damper 48 a grille 54 is provided with a plurality of horizontal linear bars. On the opposite side of the enclosure 42 an intumescent fire damper

56 is provided. The damper 56 is in the form of a grid 58 of intumescent material. Outside of the grid 58 a frame 60 is provided which mounts a further grille 62. Fig. 8 shows a duct 64 with a lower mesh grid 66. The duct 64 could be used if for instance it is required to locate the enclosure above the ceiling.

Figs. 9 and 10 show a third air transfer arrangement 68 which is similar to the arrangement 10, except that the enclosure 70 is narrower so that the sound absorbing structures 72 are transversely closer together and hence there is no line of sight therethrough, as can be seen from Fig. 10.

Figs. 1 1 and 12 show a fourth air transfer arrangement 74, which is again similar to the arrangement 10, except that the enclosure 76 is significantly broader and hence the sound absorbing structures 78 are spaced further apart. Figs. 13 and 14 show a basic air transfer arrangement 80 which comprises just three sound absorbing structures 82 with an aligned pair of structures 82, and a single structure 82 above the pair, as shown in fig. 13. Figs. 15 and 16 show an air transfer arrangement 84 for use for instance in a deep wall. In this instance seven sound absorbing structures 86 are used set out in a pattern of rows of 2-3-2.

Figs. 17 and 18 show a seventh further arrangement 88 with nine sound absorbing structures 90. These are set out in a 3-2-4 formation.

There is thus described a number of air transfer arrangements which permit a good air flow therethrough, but provide for a significant reduction of noise passing therethrough, with the structure of the arrangement helping to absorb sound across a wide range of frequencies. Such arrangements can be modified as required for particular instances. Such arrangements should be able to be readily and inexpensively produced. The range of materials used helps to provide sound absorption across a wide range of sounds. It is to be realised that a number of other modifications may be made without departing from the scope of the invention. For instance a different number or pattern of sound absorbing structures can be used as required. Different materials than those indicated may be used. The sound absorbing structures may take a different form. Some or all of the components shown for instance in Fig. 7 may be included or dispensed with, dependent on circumstances.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.