GB2290373A - Wall ducts for wall-mountable fan assemblies - Google Patents

Abstract

A fan assembly suitable for being fitted to a wall is supplied as a kit consisting of a motor-driven fan 1 and a duct 2 which extends through a passage which has been cut through a wall 3. Usually a grille 4 covers one end of the duct and a shuttered cowl 7 the other end of the duct. To overcome a packaging problem caused by the size of the tube needed for the duct 2, the tube is made up of a number of part tubular sections 12 which interlock together along edges parallel to the length of the duct. Each section may be made of two or more individual pieces to reduce the length of the tube parts, and hence the overall bulk still further. <IMAGE>

Description

WALL-MOUNTABLE FAN ASSEMBLIES AND WALL DUCTS This invention relates to fan assemblies suitable for wall mounting, and wall ducts for use in such assemblies.

Such fan assemblies consist of a duct which lines a passage through the wall, and a motordriven fan for setting up an air flow through the duct. Typically, the fan assembly also includes a grille on the air outflow side and a shutter on the air inflow side. The shutter can be closed to prevent back-draught, and is sometimes combined with the on/off switch of the fan motor, for example, both being operated by pulling a cord, so that switching on and off the fan is accompanied by opening and closing of the shutter, respectively. The fan assemblies may be for air intake or air extraction, and may be mounted on internal or external walls.

Typically the fan assembly is sold in kit form, and the parts are fitted together on site. One of the bulkiest items in the kit is the duct itself, since its minimum diameter is determined by the diameter of the fan, and its length by the maximum thickness of the wall likely to be encountered on site.

The invention provides a duct for lining the passage through a wall through which air can be driven by a wall-mountable fan assembly, wherein the duct is made up of two or more interlocking parts which each extend part way around the periphery of the duct.

By the simple expedient of fabricating the duct from a number of interlocking parts, the bulk of the overall kit is substantially reduced.

The interlocking parts may be secured together by means of co-operating interlocking formations e.g. snap-in formations, which extend along the length of each part in the direction of the length of the duct. Each of the interlocking parts may be identical in section, but each peripheral section of duct may be made up of two or more parts in the direction of the length of the duct.

A fan assembly suitable for wall mounting1 including a wall duct, constructed in accordance with the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of a first fan assembly having a duct of circular cross-section, fitted to an external wall; Figure 2 is an exploded perspective view of a second fan assembly having a duct of rectangular section, fitted to an external wall; Figure 3 is an axial section through one of four identical parts from which the duct of Figure 1 is made; Figure 4 is an axial section through four of the parts interlocked together to form the duct of Figure 1; Figure 5 is an exploded perspective view of part of the duct shown in Figure 2; Figure 6 is a schematic view of an alternative way of fabricating duct of Figure 1; and Figure 7 is a schematic view of an alternative way of fabricating the duct of Figure 2.

Like reference numerals have been given to like parts throughout all the figures.

Referring to Figure 1, a fan assembly comprises a motor-driven fan 1 and a cylindrical duct 2 which extends through an external cavity wall 3. A grille 4 is secured to the wall on its external face, and the fan is secured to the internal face of the wall by means of a flange 5 which is secured to a holder 6 which houses the fan motor. Cowl 7 is mounted on the body 6 to conceal it, and contains an integral shutter mechanism 8. In operation, a pull cord (not shown) is pulled to displace the shutters 8 to an open position and to switch the fan on, in order to extract air from the interior of the building. Another pull on the pull cord is responsible for closing the shutters 8 and switching the fan motor off. Back-draughts are then not able to blow into the building.

A fan of the kind shown in Figure 1 may be fitted to a wall after the wall has been constructed, or during construction. An adjustable length strap (not shown) extending through the duct 2 is used to hold the parts 4 and 5 together to secure the assembly in position. Duct 2 is cylindrical, and the fan motor projects outwardly from the wall, in order that the minimum amount of material has to be cut away to form the opening which the cylinder 2 lines.

Referring to Figure 2, the fan assembly illustrated may be fitted to a wall while the wall was being constructed, or after the wall had been constructed. (The duct 10 is set in mortar in the wall to secure it.) The motor is housed in the cavity in the wall, in order that the shutter mechanism does not project into the interior of the room.

Thus, fan 1 is mounted in a holder 6 which also houses the fan motor, and the holder 6 is mounted in a cowl 9 which extends into duct 10 which lines a passage through the wall, and through which air is driven by the fan 1. A fascia 11 housing shutters 8 is fitted flush to the interior of the wall, and a grille 4 is fitted to the duct 10 on the external face of the wall. The fan is operated by means of an on/off switch (not shown) which opens and closes the shutters 8 at the same time as the fan 1 is switched on and off, respectively.

Both the fan assemblies of Figure 1 and Figure 2 must be assembled on site, and one of the bulkiest items required is the duct 2 and the duct 10. These must be supplied long enough to extend through any wall which might reasonably be encountered, and, have hitherto, been made of metal or robust plastics material and have been cut to size on site.

In accordance with the invention the ducts 2, 10 are made up of two or more interlocking parts which each extend partway around the periphery of the duct. Preferably, the ducts are made of plastics material.

Thus, referring to Figure 4, the duct 2 is made up of four identical quarter cylindrical pieces 12 which have a tongue portion 13 on one end and a groove portion 14 on the other end which snap-engage with identical parts, an axial rib portion 1 3a on the end of the tongue 13 engaging in a corresponding recess in the groove 14. The tongue and groove formations run the entire length of the duct.

Now the bulk of the parts needed to fit the fan is significantly reduced, and it is only necessary to cut the quarter cylindrical parts 12 to length, to engage the four parts together and then to slide them into the passage in the wall.

If desired the duct 2 may be made of two, three or five or more identical parts.

Similarly, referring to Figure 5, the duct 10 of Figure 2 may be made of channel shaped extrusions 15 and 16 and a pair of plane extrusions 17.

The parts interlock by means of respective pairs of key-hole shaped channels 18 in one part and projecting ribs 19 with rounded heads on the other parts. Integrally formed grooves 20 enable the inner fascia 11 and the outer grille 4 to be secured to the extrusion 10.

Grooves may also be formed in similar manner extending from the internal wall of the duct, to assist in securing items such as the fascia 11 and grille 2 the ends of the duct.

If desired, the part 16 could be made identical with the part 15, and it would be readily possible to fabricate the tube from four identical parts by making each individual part include a corner and respective interlocking formations at each end.

The parts 12, 15, 16, 17 may very conveniently be extruded to manufacture them.

The fan assembly kits thus described are reduced in size compared to hitherto known kits, but the minimum packing size is still constrained by the maximum width of wall likely to be encountered.

According to a preferred feature of the invention, this is overcome by arranging that each peripheral section of the duct is made up of two or more parts in the direction of the length of the duct. Thus, referring to Figure 6, the duct is supplied as eight identical parts similar to the part 12 shown in Figure 3. It is merely necessary to cut four of the parts 21 so that the overall length of one part 12 and one part 21 is equal to the desired length of the duct.

Adjacent peripheral walls of the parts 12 and 21 are butted together, not interlocked, but so long as thejoint does not lie in line with the butted joint of the next quarter cylinder, the assembled duct has adequate structural integrity.

The same principle applies in relation to the duct 10 of Figure 2 and Figure 5. In this case the top and bottom channel sections 15 are identical, and the channel sections 22 are formed by cutting another pair of the channel sections 15 to length. The side panels 17a are made from identical side panels 17, suitably cut to length.. Again, the peripheral joints are butted and must not lie in line with butted joints in the next section of the duct. With the arrangement of Figure 7, a very wide range of wall thicknesses could be catered for by providing four channel section members 15 and four plane members 17.

While the fan assembly has been described as being suitable for wall mounting, it will be apparent that the illustrated fans would also be suitable for roof or floor mounting, or for mounting more generally on any surface with thickness e.g. a work-top.

Of course, variations may be made without departing from the scope of the invention.

Thus, the key-hole formations 19 and key-hole shaped channels 18, and the tongue and groove formations 13, 14 may be different, and other interlocking formations are possible.

Claims (3)

1. - A duct for lining the passage through a wall through which air can be driven by a wall-mountable fan assembly, wherein the duct is made up of two or more interlocking parts which each extend part way around the periphery of the duct.

2. A duct as claimed in claim 1, in which the interlocking parts are secured together by means of co-operating interlocking formations which extend along the length of each part in the direction of the length of the duct.

3. A fan assembly suitable for wall mounting substantially as hereinbefore described with reference to the accompanying drawings.

3. A duct as claimed in claim 2, in which the interlocking formations are arranged to snap-engage each other.

4. A duct as claimed in claim 2 or claim 3, in which each peripheral section of duct is made up of two or more parts in the direction of the length of the duct.

5. A duct suitable for wall mounting substantially as hereinbefore described with reference to the accompanying drawings.

6. A wall-mountable fan assembly, comprising a motor-driven fan, and a duct as claimed in any one of claims 1 to 5.

Amendments to the claims have been filed as follows 1. A wall-mountable fan assembly, comprising a motor-driven fan, and a duct for lining the passage through the wall through which air can be driven by the fan, wherein the duct is made up of two or more interlocking parts which each extend part way around the periphery of the duct, the interlocking parts being secured together by means of co-operating interlocking formations which extend along the length of each part in the direction of the length of the duct, the interlocking formations being arranged to snap-engage each other.

2. A fan assembly as claimed in claim 1, in which each peripheral section of duct is made up of two or more parts in the direction of the length of the duct.