GB2152650A - Flues - Google Patents

Abstract

A flue has a first portion (5) in use extending from the vicinity of a source of unwanted gaseous products, e.g. a gas log fire 4, a second portion (8) connected to the first portion so as to be angled with respect thereto, and exhaust fan means (16) operable to draw the gaseous products successively through the first and second portions and to discharge them from the second portion generally in the same direction to that in which they pass through the second portion. The second portion (8) may be telescopic to accommodate walls (1) of varying thickness. The fan means (16) may have its motor displaced from the flue so as not to be exposed to the gaseous products and may incorporate a motor cooling fan. <IMAGE>

Description

SPECIFICATION Flues This invention relates to flues through which pass unwanted gases such as products of combustion and whilst the invention has been conceived primarily in connection with socalled gas log fires, it has other applications.

Gas log fires are fires in which a real gas flame plays on imitation logs and embers whereby the latter are heated and glow to resemble an authentic log fire. Gas coal fires based on the same principal are also known.

To date, the installation of gas log or coal fires, as well as other types of fires, has been dependant on there being an existing fireplace, and hence chimney, in the room concerned. Thus some properties cannot entertain the possibility of installing a gas log or coal fire and even those fitted with one or more fireplaces and chimneys are restricted as to the precise location of the installaion. This means that a room or workshop, for example, has to be designed around the existing fireplace or chimney, thereby cramping the style of the designer.

According to the present invention there is provided a flue have a first portion in use extending from the vicinity of a source of unwanted gaseous producs, a second portion connectible to the first portion and being angled with respect thereto when connected, and exhaust fan means operable to draw said gaseous products successively through the first and second portions and to discharge them from the second portion generally in the same direction to that in which they pass through the second portion.

In as much as the unwanted gaseous products are normally required to be discharged exteriorly of a room or building, the second flue portion may be adapted to pass through the appropriate wall, with the exhaust fan means located on the outer end of the second portion. Preferably, the second flue potion is dimensioned so as pass through the opening left by the removal of one building unit or brick from the wall (one from each skin in the case of a cavity wall) thus minimising the installation time and structural disturbance. In the case of a domestic installation involving a normal brick built house, .hue second flue portion is made rectangular and dimensioned the same as the front face of a standard building brick, i.e. 9" x 3" (230mm X 76mm). In order to accommodate varying thicknesses of wall, the second flue portion by the made telescopic.

When the unwanted gaseous products are products of combustion, the temperature thereof is relatively high and can be detrimental to a fan motor if the latter is located in the stream of the gaseous products being discharged by the fan means because the motor lubricants dry up and the motor is likely to sieze. Therefore, in accordance with a preferred feature of the present invention, the exhaust fan means comprises a fan rotor or fan wheel disposed substantially in alignment with the second flue portion, the rotor being driven by a motor displaced from the second flue portion so as not to be exposed to the gaseous products in use flowing through the second portion. The exhaust fan means may include a cooling fan disposed between the fan wheel and the motor.

Several flues constructed in accordance with the present invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: Figures 1 to 3 are diagrammatic crosssectional side views of three different embodiments of flue, Figure 4 is an enlarged view of a portion of Fig. 1 Figure 5 is a front view of a component of Fig. 1, and Figure 6 is a plane view, partly in section, of Fig. 5.

Referring first to Fig. 1, this illustrates a portion of a room bounded in part by a cavity wall 1 on one side and a ceiling 2. Adjacent the wall 1 there is installed a fireplace 3 comprising a fire basket or grate 4 which may be of the gas log or gas coal fire type, or a real open log, coal or other fueld fire. As already mentioned, a gas log or coal fire is one in which a gas flame plays on articifical ceramic iogs or coal to give a real log or coal fire effect without the attendant mess of ashes and soot.

A flue extends from above the grate 4 and comprises a first cylindrical portion 5 extending substantially vertical adjacent the inner skin of the wall 1 and having a flared lower end portion 6 which forms a gatherer for the products of combustion from the fire 3. The first portion 5 of the flue is of a double skin construction formed from sheet stainless steel with an insulating material 7 disposed between the skins. The flue further comprises a second portion 8 which is of rectangular cross section dimensioned approximately 9" x 3" (230mm x 76mm), i.e. the same size as a standard building brick as seen in front view.

The second flue portion 8 is made telescopic (as seen in Fig. 4) in order to accommodate varying thicknesses of the wall 1 and thus has a portion 9 which slides within a further portion 11. The portion 9 has a circular aperture 1 2 in the bottom thereof, which aperture is surrounded by a depending annular flange 1 3 dimensioned to fit closely over the upper end of the first flue portion 5, the two components normally being sealed together in a gas-tight manner on installation by a sealant. The portion 9 is also provided with an encircling flange 14 by which that portion is bolted or otherwise secured to the inner skin of the wall 1.

The further portion 11 of the second flue portion 9 is also provided with an encircling and terminal flange 1 5 by which that portion is attached to the outer skin of the wall 1. The seond flue portion 8 is fabricated from sheet steel. To the outer end of the further portion 11 there is fitted exhaust fan means 1 6 comprising a housing 1 7 which is closed at the top, bottom and sides but open, or at least apertured, at the rear so as to connect with the second flue portion 8, and open or louvred at the front. The housing has a flange 18 similar in size and shape to the flange 15, the two flanges being together bolted or otherwise secured to the outer skin of the wall 1 with an anti-vibration gasket 1 9 disposed therebetween.

The exhaust fan means 1 6 further comprises a motor 21, a centrifugal type cooling fan 22, and a cross flow type exhaust fan 23 as seen in Figs. 5 and 6, these components being mounted in the housing 1 7. The motor 21 drives both the cooling fan (to cool the motor) and the exhaust fan 23, the latter serving, in use. to draw air and the products of combustion of the fire in the fireplace 3 up through the flue 5, 8 and to discharge the same through the louvred front of the housing 1 7 in a direction generally the same as that in which the air and products of combustion flow through the second flue portion 8. Thus the products of combustion are discharged in a direction away from the outer skin of the wall 1, whereby the latter is not marked which otherwise would be the case.

It will be seen from Fig. 6 that the motor 21 is displaced with respect to the second flue portion 8, whereby it is not in the stream of air and products of combustion flowing through the latter. If it were, then the relatively high temperatues involved would tend to dry the motor lubricant with a likelihood of the motor seizing. Thus with this arrangement, the motor will have a long life and there will be an efficient extraction of the products of combustion through the flue 5, 9 as well as a good updraught for the fire in the fireplace 3 which is important.

Fig. 1 shows the flue 5, 8 hidden behind a false chimney breast or box 24, with the firepiace surrounded by a carved wooden surround of which only the mantlepiece 25 is shown. Thus it will be appreciated that with the use of a flue in accordance with the present invention a fireplace can be installed in a room which does not have the benefit of a chimney, there being no restriction as to the siting of the fireplace which can be in a corner, in the body of the room, or on any wall whether interior or exterior. If a comparatively long second flue portion 8 is required in order to connect the first portion 5 to an exterior wall, it can be boxed, disguised as a beam or otherwise hidden.Furthermore, the installation of the flue is made simple by dimensioning the second flue portion 8 the same as a standard building brick so that only a single brick needs to be removed from the or each skin of the exterior wall. When the bricks have been removed, the flue portion 11 is inserted in the resulting aperture, which aperture it snugly fits, and is then bolted to the outer skin of the wall 1, together with the fan means 16, using the flanges 1 5 and 1 8 with the gasket 1 9 disposed therebetween.

The flue portion 9 is then inserted into the wall aperture from within the room and outer end is slid into the flue portion 11. The flue portion 9 is then bolted to the inner skin of the wall 1 via the flange 14. Finally, the flue portion 5 is assembled on, and sealed to, the portion 9 using the flange 13. The structural disturbance to the property is thus very minimal and the installation can be effected relatively quickly.

Fig. 2 and 3 of the drawings show two different embodiments of flue, the difference concerning only the first flue portion 5 which in Fig. 2 has a single skin gatherer 6 since a metal canopy 26 is used to hide the flue 5, 8 instead of a false chimney breast. In Fig. 3 a laboratory, workshop or similar application is shown in which the first flue portion 5 is in the form of a single skin flared member 27 into which unwanted gases (be they products of combustion or otherwise) are drawn by the exhaust fan means 1 6. It will be appreciated that there are numerous other applications of a flue constructed in accorfdance with the present invention, which flue allows complete freedom as regards the installation of a fireplace, etc. with minimal structural alterations.

Claims (9)

1. A flue having a first portion in use extending from the vicinity of a source of unwanted gaseous products, a second portion connectible to the first portion and being angled with respect thereto when connected, and exhaust fan means operable to draw said gaseous products successively through the first and second portions and to discharge them from the second portion generally in the same direction to that in which they pass through the second portion.

2. A flue according to claim 1, wherein the second portion is telescopic so as to be adjustable to suit the thickness of a member through which it passes.

3. A flue according to claim 1 or 2, wherein the second portion in use passes through a wall constructed of building blocks, and wherein the second portion has a crosssectional shape and is dimensioned similar to one of the building blocks which on assembly it thus replaces.

4. A flue according to any of the preceding claims, wherein the exhaust fan means comprises a fan rotor or fan wheel disposed substantially in alignment with the second flue portion, and a motor operable to drive the rotor and displaced from the second flue portion so as not to be exposed to the gaseous products in use flowing through the second portion.

5. A flue according to claim 4, wherein the exhaust fan means includes a cooling fan disposed between the motor and the rotor.

6. A flue according to claim 4 or 5, wherein the exhaust fan means is of the crossflow type.

7. A flue according to claim 2 and any claim appended thereto, wherein each part of the telescopic second flue portion is provided with a first flange by which that part is in use attachable to adjacent structure.

8. A flue according to any of the preceding claims, wherein the second flue portion is provided with a second flange around an aperture, the second flange serving to locate the second portion relative to the first portion on assembly of these two components.

9. A flue according to any of the preceding claims, wherein the first flue portion is of double skin construction with an insulating material disposed between the skins.

1 0. A flue substantially as herein particularly described with reference to Fig. 1 or Fig.

2 or Fig. 3 taken with Figs. 4, 5 and 6 of the accompanying drawings.