GB2338289A

GB2338289A - A housing for an exhaust fan

Info

Publication number: GB2338289A
Application number: GB9918770A
Authority: GB
Inventors: Charles Nicholas Portway
Original assignee: Taylor & Portway Ltd
Current assignee: Taylor & Portway Ltd
Priority date: 1997-06-16
Filing date: 1997-06-16
Publication date: 1999-12-15
Anticipated expiration: 2017-06-16
Also published as: GB9918770D0; GB9712522D0; GB2326466A; GB2338289B

Abstract

A housing for a tangential exhaust fan for a fan flue gas fire, said housing being adapted so as to be mounted substantially within the width of an exterior wall of a building. An outlet for the fan extends downwardly away from the wall. An air pressure switch (41) senses operation of the fan and senses obstruction in the flue system and thereby switches off the fire. The switch is connected by sensing tubes (61, 63) to the fan outlet; the end of tube (61) extending upwardly (62) to detect operation of the fan.

Description

2338289 1 FAN FLUE GAS FIRE ASSEMBLY The present invention relates to a

fan flue gas fire assembly.

0 By fan flue gas fire we mean a gas fire, primarily for a domestic environment, in which the flue gases from the gas fire are drawn away from the gas fire to the outside of the building by means of a fan. Whilst such a fan may be used to assist a conventional vertical flue above the aas fire, in the arranaement which is described the aas fire is arranced in a situation in which there is no vertical flue. The flue aases 10 are either drawn by a fan from the rear of the fire directly through an outside wall on which the gas fire is mounted, or are passed along generally horizontal trunking from the gas fire through to an outside wall adjacent which is mounted a fan to draw the flue gases through the trunking and to disperse the flue gases outside the building. Such an arrangement is well known in which the trunking is disguised so as to appear 15 like a wide skirtina board. In both cases, the fan, which may electrically driven, is mounted on a box on the outside wall of the building.

Such an arrangement has become very popular as it enables a builder to build a house without a chimney (vertical flue) and yet to incorporate a gas fire. There are, however, a number of difficulties which the present invention seeks to reduce or overcome. The provision of a box including the fan on the outside of the building, typically on a front wall of the building adjacent the front door, is somewhat unattractive. Furthermore, simple arrangements need to be provided to mount the trunking in a safe manner within the building.

The present invention provides, according to a first aspect, a housing for a fan for a fan flue gas fire, said housing being adapted so as to be mounted substantially within C C - the width of an exterior wall of a building.

Mounting the extractor fan in a housing within the width of the wall reduces the visible impact of the housing, and thereby improves the appearance. 'Mere are, 2 however, a number of difficulties in providing such a housing. Firstly, the fan may overheat and so means are provided to cool the housing, said means comprising means to entrain cooling air with the flue gas being exhausted by the fan, said cooling air entering the housing through a suitably disposed opening. In a preferred arrangement, the housing incudes an opening adjacent its top edge and the fan exhausts flue gas throUah an outlet, the outlet having a sleeve spaced from and extending around the outlet of the exhaust fan, whereby air is entrained and drawn through the housing.

0 Mounting the exhaust fan with its rotational axis horizontal in the normal configuration would not provide a suitable outlet and accordingly the extractor fan is mounted with its rotational axis at an angle to the horizontal, in the range 20 - 7T; preferably 45 degrees.

0 is We will also describe a joint means for joining two sections of trunking which trunking interconnects the gas fire and the outlet, said joint means incorporating spacers which may connect the joint means to adjacent walls andlor floors, and to which suitable decorative panels may be attached, said spacers extending around at least three sides of the joint means and being spaced from the trunking, whereby the trunking is spaced from adjacent surfaces (such as the decorative panels or the wall) to provide a cooling space between the hot surfaces of the trunking and the adjacent surfaces.

A preferred embodiment of the invention will now be described by way of example only and with reference the accompanying drawings in which:Fiaure 1 is a diaarammatic view of a fan aas fire assembly comprising a fan flue gas 0 0 0 fire, flue gas trunking, and flue gas outlet means, 0 Figure 2 is a diagrammatic partly cut away front view and Figure 3 is a similar side view of the flue gas outlet means, 3 Figure 4 is a perspective view of apparatus mounted within the flue gas outlet means of Figures 2 and 3.

Figure 5 is a end view, and Figure 6 a side view of a first embodiment of trunk-ina joint, and Figure 7 is an end view corresponding to Figure 5 of an alternative trunking joint.

0 0 10 1= Referring to Figure 1, there is shown a fan flue gas fire system 10 in diagrammatic form which comprises a fan flue gas fire 11, the flue gas from which passes from the fire 11 into horizontal trunking 12 arranged adjacent to the floor and wall of a room 0 C in which the cas fire is mounted, the sections of trunking 12 being joined by a joint 0 0 13, the trunking 12 passing out through an outside wall 18 of the building into a flue gas outlet means 14 which is mounted substantially within the thickness of the outside 0 wall 18, the flue gas outlet means 14 comprising a flue gas outlet housing 16 in which 0 0 is mounted an electric motor driven tangential fan 17.

0 The system 10 as shown in Figure 1 allows a house builder to incorporate in a house a aas fire 11 into a room which does not have a vertical flue leadina to a chimney, the flue gas being collected and passed from the fire 11 into the trunking 12. The flue gas is sucked aloncr the trunking 12 and exhausted to the outside of the outside c wall 18 by means of the fan 17.

nere is provided an electrical interconnection between the electric fan 17 and the gas fire 11, and there is also provided pressure detectors as will be described later, so that if the electric fan 17 ceases operation or there is an obstruction so that the fumes from the gas fire 11 are not passing out through the fan 17, then the gas fire 11 is automatically switched off.

In prior arrangements, the housing 16 is mounted on the outside of the outside wall 18 but as is clear from Figure 1, in the present invention, the housing 16 is mounted 4 substantially within the depth of the outside wall 18. As a result it is necessary to keep the housing 16 cool and where a tangential fan 17 is used, in which air enters 0 the fan along its axis and passes out tangentially during rotation of the fan, it is necessary to tilt the fan so that the flue gas outlet is at an angle and projects away from the outside wall 18.

We will now describe in further detail the arrangement of the flue gas outlet means 14 with reference to Figures 2, 3 and 4. Referring to Figure 2 and 3, it will be seen that the housing 16 comprises a box 19 which may be of galvanised steel and comprising a rear wall 22, lower wall 27 and side walls 28, 29 with an open front face to which is attached a front cover 21. The rear wall 22 of the box 19 incorporates a hole 23 surrounded by a collar 24 adapted to engage with the trunking 12. The hole 23 communicates with a generally closed section 26 of the box formed by the rear wall 22, lower wall 27 and side walls 28, 29 of the box 19 and an angled internal wall 31. As is clear from Figure 3 the internal wall 31 is angled at 45 dearees to the horizontal and mounts the tanaential fan 17. A hole is provided in the centre of the internal wall 31 so that air may be drawn out of the closed section 1-6 by the tangential fan 17. The outlet 32 for the tangential fan 17 is then arranged to be directed at 45 dearees downwards to the horizontal. The outlet 32 is surrounded by a sleeve 33 the sleeve 33 being larger than the outlet 32 and extending from a position 34 inward of the outlet 32 to a grille 36.

The front cover 21 incorporates adjacent to its upper most edge a slot 37 which allows air to pass from the outside into the interior of the box 19.

Referring to Figure 4, it will be seen that the box 19 mounts various control means, including a fan controller 38, resistors 39, an air pressure switch 41 which is connected by means of tubes, not shown, to two positions within the outlet 32 as will be described hereafter, a fan speed regulator switch 42, and a heat deflector 43.

0 The air pressure switch 41 comprises a diaphragm mounted between two closed 1 chambers, the movement of the diaphragm operating the switch, one closed chamber being connected by a pipe 61 (see Figure 2) to an open ended pitot tube 62 which points upwardly at the fan outlet, and the other closed chamber being connected by a pipe 63 to a second open tube 64 mounted in the fan outlet, which has its open end pointing across the fan outlet. The first pitot tube 62 thus detects operation of the fan and pressure providing by operation of the fan, and the second tube 64 detects flow of air through the outlet of the fan. In this manner, both failure of the fan to rotate and provide pressure, and blockage of the outlet, will be detected.

0 We now refer to Figures 5 and 6 which show details of a joint 13 for mounting together two lengths of trunking 12. The joint is made of folded galvanised steel. As can be seen, the joint 13 comprises a main body 44 of rectangular cross section into which the two ends of adjacent lengths of trunking 12 may be inserted and screws may be inserted through suitable holes such as holes 46 to connect the ends of the two lenaths of trunkina 12 to the joint 13. Self-tapping screws 40 may be used to connect the trunking 12 to the joint 13 and a sleeve 45 of sealing material may be provided on the inner surfaces of the body 44 so as to provide an air tight seal between the inner surfaces of the body 44 and the outer surface of the trunking. Above the body 44 is mounted a spacer fitting 47 which includes a horizontal mounting plate 48 and two vertical mounting plates, 53, 54, and below the body 44 is mounted a lower fitting 49 the ends of which are upturned to provide spaced mounting plates 51 and 52. It is noted that the mounting plates 48, 51, 52, 53, 54 are spaced by at least 25 mm from the body 44.

The fitting 47 may be mounted to an adjacent wall 50 of the building and the floor 60 by screws 55, 61 through either the mounting plates 51 on one side of the body 44 or the corresponding upper mounting plate 53 and the lower surface of the body 44. This spaces the body 44 and hence the trunking from the wall of the building.

A finishing decorative panel 56 may be mounted (eg by screws) to the other vertical mounting plates 52, 54 and once again this finishing plate will be spaced from the 0 6 body 44 and hence from the trunking. An upper horizontal finishing panel 57 may be mounted (eg by screws) to the mounting plate 48 which is again spaced from the body 44 and hence from the trunking.

It will be understood that when the finishing panels 56, 57 have been mounted to the C joints 13, there is provided a space behind them of at least 25mm so that heat from the trunkina 12 is not transmitted to the finishing panels.

C 0 Thus the finishina panels may be made of a material such as wood which should not 0 come into contact with hot surfaces.

In the alternative arrangement of joint 13 shown in Figure 7, the lower fitting 49 incorporates a spacing part 58. The joint of Figures 5 and 6 may be only be used 0 where there is a non-flammable, for example, concrete floors, since the body 44 is directly amounted to the floor, whereas the joint of Figure 7 may be mounted to a wooden floor as the body 44 and hence the trunking 12 is spaced from the floor by spacing part 58.

Although not shown, there is an electrical connection between the gas fire 11 and the flue gas outlet housing 16.

0 C In use, when the user wishes to operate the gas fire 11, the gas fire 11 is switched on in the norTnal way. Before the gas fire 11 operates, a signal is passed to the fan 0 controller 38 which starts the fan 17. When the air pressure switch 41 senses that the fan 17 is in operation, by measuring the pressure differential, then the gas fire 11 ignition sequence may start the gas fire.

It will be understood that the fan 17 pulls the exhaust gas from the gas fire 11 along the trunking 12 to the hole 23, (as indicated by arrows in Figure 3), the air then passes through the axis of the fan 17 and is passed out of the fan 17 via the outlet 32 and out through the grille 36 outside the wall 18. The movement of the flue gas is 0 7 illustrated in Figures 2 and 3 by the wide arrows.

The movement of the flue aas out of the outlet 32 entrains, by means of the venturi effect air from the inside the housing 16 via the gap between the sleeve 33 and the outlet 32. This reduces the pressure within the housing 16 so that air flows in via the slot 37 at the top of the housing. In this way cool air (indicated in Figures 2 and 3 by the narrow arrows) passes from the slot 37 through the interior of the housing 16 and out through the grille 36 along with the flue gas. This keeps the components within the housing cool, in particular the motor driving the fan 17 and the resistors 39 and prevents the housing 16 becoming too hot. This enables the housing 16 to be mounted within the wall 18.

If for any reason the flow of flue gas through the system is obstructed, then the air 0 0 pressure switch will sense that and will switch off the gas fire 11.

Timer means may be provided to continue operation of the fan 17 for a period of time after the aas fire 11 has been switched off.

0 The invention is not restricted to the details of the foregoing example.

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Claims

CLAIMS is 1. A housing for an exhaust fan for a fan flue gas fire, said

housing being adapted so as to be mounted substantially within the width of an exterior wall of a building. said housing including means to mount a tangential exhaust fan, means to connect to a generally horizontal trunking connected to the flue of a fan flue gas fire, and an outlet through which the fan exhausts flue gas outside said exterior wall of the building, the outlet projecting away from the exterior wall of the building and downwardly.
2. A housing as claimed in claim 1 in which an air pressure switch is provided in said outlet to sense operation of the exhaust fan and to sense obstruction in the system and thereby switch og the gas fire.
A housing as claimed in claim 1 or 2 wherein means are provided to cool the g housing, said means comprising: means to pass cooling air through said housing from outside said housing and from outside said exterior wag of the building.
4. A housing as claimed in claim wherein said cooling means comprises means to entrain cooling air with the flue gas being exhausted by the fan, an opening in said housing to outside said exterior wall of the building allowing said cooling air to enter the housing.
5. A housine as claimed in claim 4 wherein said Outlet includes a sleeve spaced from and extending around an outlet of the exhaust fan, said sleeve communicating with the interior of the housing so that air is entrained and drawn through the housing from said opening.

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6. A housing as claimed in any of claims 1 to 5 wherein said trunking includes a plurality of sections of trunking joined by a joint means, said joint means incorporating spacers which may connect the joint means to adjacent walls and/or floors andlor to suitable decorative panels, said spacers extending around at least three sides of the joint means and being spaced from the trunking whereby the trunking is spaced from all 0 adjacent surfaces to provide a cooling space between the hot surfaces ofthe tunldng and the adjacent surfaces.