GB2352025A

GB2352025A - Flue system

Info

Publication number: GB2352025A
Application number: GB9916268A
Authority: GB
Inventors: Michael Langton
Original assignee: BAXI HEATING Ltd; POTTERTON MYSON Ltd
Current assignee: BAXI HEATING Ltd; POTTERTON MYSON Ltd
Priority date: 1999-07-13
Filing date: 1999-07-13
Publication date: 2001-01-17
Also published as: GB9916268D0

Abstract

A flue system for use with a combustion driven appliance 201 comprises connection means for connecting the flue to the appliance 201, passage means 206 for enabling passage of combustion products from the appliance 201 to the outer environment and means 304, located substantially within said passage means 206, for forcing said combustion products through said passage means 206. The combustion product forcing means may comprise an electro-mechanical fan 304 configured to draw the combustion products through the flue duct. The connection means may comprise an end of the flue member. The flue enables a power assisted flue arrangement or a fanned balanced flue arrangement to be fitted from the inside of a given room.

Description

2352025 IMPROVEMENTS TO FLUE ARRANGEMENTS

Field of the Invention

The present invention relates to the field of flue arrangements and 5 particularly, although not exclusively to flue arrangements used in conjunction with heating appliances.

Background to the Invention

Combustion driven appliances such as heating appliances are known for lo heating domestic or commercial premises for a variety of heating requirements.

Thus, for example a domestic household may comprise a boiler for heating a domestic water supply so as to provide central heating throughout the building and hot water for use in cleaning and washing. Similarly, a domestic building may also comprise a gas fire for heating a given room of the building. Domestic heating appliances such as gas fires and gas boilers generally are required to bum gaseous fuel such as methane whereafter combustion products are required to be directed to the outer environment away from the domestic premises. Typically combustion products are passed from a domestic heating or cooking appliance to the outer environment via a flue arrangement which is typically configured to pass through a wall of the building in which the heating or cooking appliance is located.

Various types of flue arrangements are known such as balanced flue arrangements and power assisted flue arrangements. Balanced flue arrangements have various advantages over power assisted flue arrangements, but in general, power assisted flue arrangements have the advantage of being able to utilise a narrower aperture flue. Powered flues are configured to exhaust the waste products of combustion through a single duct, the combustion air being supplied from the room in which the combustion appliance is located. A narrower flue aperture usually means that less damage to the building structure is involved P335-sper- during installation of such a flue. Also balanced flue arrangements may not be suitable for certain applications such as, for example, location of a flue arrangement near a corner (within 600 mm is usually specified) of a building since then the flow of air circulating the outer aperture of the flue arrangement is disturbed. For many applications it is found that a power assisted flue arrangement is more suitable, such an arrangement comprising a fan located towards the outer aperture of the flue arrangement so as to effectively draw the waste combustion products from the given heating appliance to the outer environment. A power assisted flue arrangement of this kind is typically driven by lo an electro-mechanical fan located as far away as possible from the given heating appliance. Figure 1 schematically illustrates, in cross section a gas fire 101 located on a substantially combustion resistant base 102 and connected to the outer environment by a flue coupling means 103 and prior art flue 104. Flue 104 may comprise a substantially cylindrical steel tube configured to pass through wall 105. Wall 105 may comprise an inner portion 106 and an outer portion 107, the two portions forming a cavity 108 in between. Fire 101 is located substantially in front of a heat resistant shield 109. Flue 104 is connected to and shielded from the outer environment via an outer covering 110 which may comprise a box like structure. Box 110 comprises an electro-mechanical fan 111 configured to draw combustion products from domestic heating appliance 101 through flue arrangement 103, 104. Upon reaching box 110 the combustion products are directed through appropriately configured orifices 112. Electromechanical fan 111 is powered by a domestic mains lead 113 which due to the temperature of the combustion products in flue 104 is generally fed into the building via an electric cable located externally to flue system 104 and casing 110. Casing 110 is affixed to wall 105 via attachment means 114 which may comprise bolts drilled into wall 105.

The power assisted flue arrangement identified in figure 1 is particularly 30 suitable for domestic appliances located on the ground floor of a given building, but is found to be difficult to install and maintain in a variety of locations such as, for example, on higher floors of multi-storey buildings. In particular, it is found that casing 110 housing electro-mechanical fan I 11 has to be affixed to wall 105 from the outside of the building. Thus, although gas fire 101 can be installed from within a high rise building for example, casing 110 holding fan 111 must be installed from the outside of the building. Furthermore, fan 111 is positioned external to wall 105 so that noise generated by fan 111 is substantially attenuated on reaching the room located behind internal wall portion 106. Various methods of reducing noise of this kind are known, such as placing fan 111 on rubber lo bosses so as to reduce vibration and noise.

From the above it is clear that there is a need for an improved power assisted flue arrangement which maintains acceptable levels of noise to the owner of a given combustion driven appliance, but which is able to be installed and maintained from the inside of a given building.

Balanced flues' provide a means of both extracting the exhaust products of combustion and supplying the air required for combustion. This usually takes the form of a central duct for exhaust and an outer annulus for air supply. These ducts are mechanically separated. The movement of the air/waste products can be fan driven and these are known as fanned flues, but they are balanced flues.

Fanned flues offer advantages in certain circumstances over power assisted flues and/or conventional balanced flues. In common with the problems identified above in respect of power assisted flues, in circumstances where a fanned flue is the preferred option then there is a need for an improved fanned flue arrangement which maintains acceptable levels of noise to the owner of a given heating appliance, but which is able to be installed and maintained from the inside of a given building.

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Preferably said waste product forcing means comprises an electro mechanical fan configured to draw said waste products through said passage means, Preferably said waste product forcing means is electdcally powered via mains electricity transmission means configured to pass substantially within said waste product passage means.

Preferably said electricity transmission means comprises materials configured to withstand temperatures in the range NOT to 300T.

Preferably said electricity transmission means is contained within a substantially heat resistant structure located within said passage means, said heat resistance being effective in the range 200T to 300T.

Suitably the heat resistant said structure comprises an elongate hollow member configured to cover said electricity transmission means throughout the length of said passage means.

Preferably said passage means compdses an elongate hollow member having a substantially circular cross section.

Preferably said passage means comprises an elongate hollow member having a substantially square cross section.

Preferably said waste product forcing means is substantially permanently fixed to said passage means.

Preferably said passage means comprises a grid like member positioned transversely to a main length of said passage means, said waste product forcing means being fixed to said grid.

Preferably said waste product forcing means is operated in response to flow detection means configured to monitor flow of said waste products.

Preferably said appliance is a heating appliance configured to heat a portion of a building.

Preferably said heating appliance is a gas fire or a gas boiler.

Preferably said passage means is configured for fitment in an orifice bored through an outside wall of a building.

Preferably said passage means is additionally configured to position said forcing means substantially on the outside of an outside wall of a building, Preferably said arrangement comprises a fanned balanced flue.

According to a second aspect of the present invention there is provided a method of installing a flue arrangement in a building, said flue being configurable for use in extracting substantially gaseous waste products from an appliance generating said products through combustion, said method comprising the steps Of -.

entering a room in which said appliance is to be located and selecting a suitable outside structure for fitment of said flue; from the inside of said room boring a passage through said outside structure; and from said inside of said room, inserting an elongate hollow flue member within said passage, said member comprising means, fitted within said member, for forcing said waste products along said member.

Preferably said room is a room located on the first floor or a higher floor of a multi-storey building.

Preferably said appliance is a gas fire.

Preferably said appliance is a boiler configurable to heat a building or a portion of a building.

Preferably said step of boring said passage further comprises the step of:

smoothing the walls of said passage so as to facilitate said subsequent insertion of said flue member via sliding said flue member into position.

Preferably said smoothing step comprises insertion of a flue passage liner 25 structure.

Preferably said waste product forcing means comprises an electromechanical fan.

Preferably said forcing means is electrically powered via a mains lead passed through the inside of said elongate hollow flue member.

Preferably said flue arrangement comprises a fanned balanced flue.

Suitably said outside structure comprises a wall of a building.

Preferably said member is fitted, following said insertion step, such that said forcing means is positioned substantially outside said outer structure.

Brief Description of the Drawino

For a better understanding of the invention and to show how the same may be carried into effect, there will now be described by way of example only, specific embodiments, methods and processes according to the present 15 invention with reference to the accompanying drawings in which:

Fig. 1 schematically illustrates a prior art flue arrangement as used in conjunction with conventional gas fire;

Fig. 2 schematically illustrates a prior art flue arrangement as used in conjunction with a conventional gas fire; Fig. 2 schematically illustrates a domestic gas fire of a kind suitable for use with the present invention; Fig. 3 schematically illustrates, in cross-section, a preferred embodiment of the present invention wherein an electro-mechanical fan is located within a horizontal flue member; and Fig. 4 schematically illustrates the steps involved in installing a flue arrangement which has been configured in accordance with the present invention.

Detailed Description of the Best Mode for -Garrying Out the Invention

There will now be described by way of example the best mode contemplated by the inventors for carrying out the invention. In the following description numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent however, to one lo skilled in the art, that the present invention may be practiced without limitation to these specific details. In other instances, well known methods and structures have not been described in detail so as not to unnecessarily obscure the present invention.

Figure 2 schematically illustrates a domestic gas fire of a type typically found in many domestic households. Gas fire 201 is configured to bum a mixture of methane gas and air wherein the methane is supplied via a conventional domestic gas supply and the air is drawn in through a front grill of gas fire 201.

Gas fire 201 has a decorative canopy 202, the whole assembly being surrounded by a hearth structure 203. The gas fire assembly 201, 202 is located against wall 204 in, for example, a domestic living room. However, the arrangement identified in Figure 2 is meant to be an example of a typical application of the present invention and may comprise a domestic gas fire, a domestic boiler or a gas fire or boiler located in commercial or industrial premises. Gas fire 201 further comprises a flue arrangement located behind canopy 202. The flue arrangement associated with gas fire 201 is located substantially behind canopy 202 and therefore in Figure 2 is shown as broken lines, the flue arrangement comprising vertical outlet 205 which connects with horizontal outlet 206. Horizontal flue member 206 is located substantially within wall 204 forming a passage from the inside of the room to the outer environment located on the outside of wall 204.

Member 206 may typically- comprise a portion of cylindrical steel tube which has means for facilitating connection of the member to a suitable appliance. The connection means may be considered to be simply an 'end' of the member or may comprise a specifically configured connection arrangement. The arrangement identified in Figure 2 is suitable for incorporating the present invention and maybe located in any domestic or commercial premises including rooms located on floors other than the ground floor of multi-storey buildings. The gas fire 201 is an example of a combustion driven heating appliance - that is an appliance, domestic or industrial, which generates heat and waste products lo through the process of combustion. Thus, gas fires and boilers, oil fires and coal fires and boilers are all examples of such devices.

Flue arrangement 205, 206 is further schematically illustrated in cross section in Figure 3. Many of the components identified in Figure I in the background to the invention are similarly present in the arrangement identified in

Figure 3 and therefore will not be further described. Outside wall 204 is seen to comprise a cavity arrangement comprising a first structure forming an internal wall and a second structure forming an external layer of the wall. By outside wall it is meant herein a wall which has at least a portion of one of its faces exposed to the outer environment. The flue arrangement configured in accordance with the present invention may be suitable for placing in a variety of "outside" structures including structures such as walls and roofs of buildings. The horizontal portion of the flue arrangement, portion 206, comprises an elongate hollow member which may suitably be formed from a steel cylinder or a hollow steel elongate rectangular structure. The exact shape of member 206 may vary depending on the particular application or on a given builders preferences. Flue arrangement 205, 206 is further illustrated in terms of its external appearance in section at 301. Thus, flue arrangement 301 comprises an outer edge 302 which overhangs a cavity formed within member 206. In accordance with the present invention member 206 further comprises a power unit 303 which in the best mode herein comprises an electro-mechanical fan having a propeller 304. Fan 303 is configured to draw the combustion gases, resulting from the appliance, to the outside environment. Fan 303 may be suitably attached to member 206 via attachment to vertically held grid member 305. Gdd member 305 may be firmly attached to the inner walls of member 206 such that above and below fan 303 there is provided space for combustion product gases to escape through member 305. In the preferred embodiment the grid member is positioned transversely to a main length of the member 206, and it is further preferred that the grid is positioned both perpendicular to said main length and substantially parallel to a lo plane comprising an opening at one or both of its ends. In other words for a horizontally mounted flue, in the preferred embodiment, the grid is mounted vertically in a plane perpendicular to the central axis running along the centre of a main length of the flue structure. Fan 303 may be powered by a domestic mains supply via domestic mains lead 306 which, as illustrated, runs along the inside of member 206 from behind domestic gas fire 201. Thus, the power unit 303 and power lead 306 are preferably both located within flue member 206 and thus upon Installation of gas fire 201, member 206 may be passed through wall 204 from the inside of the room in which the gas fire is to be located. The walls of member 206 suitably extend beyond grid member 305 so as to further protect fan 303 from weather such as rain.

Figure 3 identifies a first preferred embodiment of the present invention and it is to be understood by those skilled in the art that other configurations may also provide the advantages of the invention described herein. Thus, for example, fan 303 located within member 206 may be located substantially within the confines of the outer surface of wall 204, in this case member 206 terminating substantially at the outer surface of wall 205. Similarly, mains lead 306 may be further protected by incorporation in a substantially heat resistant covered channel located within member 206 so as to further protect lead 306 from the heated combustion gases passing along member 206 from gas fire appliance 201. In the preferred embodiment mains lead 306 is of a type designed for operation in temperature conditions of between 200"C and 3000C since typical temperatures found within gas fire appliance flue arrangements are of the order of 200'C - 300'C. The preferred embodiment, identified in Figure 3, comprises an extended duct 206 extending beyond the outer surface of wall 205, this being preferred so as to further distance fan 303 from gas fire appliance 201. In this way any noise generated by fan 303 is further reduced from the point of view of the owner of gas fire appliance 201. Noise may be further limited by attachment of fan 303 to vibration damping means which in turn is connected to grid lo arrangement 305. Suitable vibration damping means may comprise a substantially heat resistant rubber like material placed between fan 303 and grid arrangement 305. Finally, as is known with powered flue system in general, in the best mode herein, the invention also comprises use of a flow detection means 307 which may suitably be fixed to fan 303. Fluid flow detection means 307 may be powered via domestic mains power lead 306 with fan 303 being powered in response to the amount of flow detected. Thus, the power delivered to fan 303 may be adjusted in response to the amount of flow detected by flow detection means 307. As is known in the art, flow detection means 307 may be precalibrated prior to installation of fan 303 in flue passage member 206.

Unlike with prior art powered flue arrangements a flue arrangement configured in accordance with the present invention may be fitted through a building wall from the inside of the building. The steps involved in installing a flue arranged in accordance with the present invention are detailed in Figure 4. In step 401 an appropriately qualified heating engineer enters the room in which the gas appliance is to be fitted. In the preferred embodiment the gas appliance is a gas fire to be fitted in a first or higher floor of a multi-storey building. Having entered the room designated for fitment of the gas appliance, the heating engineer is required to read the flue specification in step 402 so as to check the flue requirements for the gas appliance to be fitted in the room entered in step 401. Having ascertained the details of the flue arrangement to be configured in the room the heating engineer is required to assemble a core drill in accordance with the specification ascertained in step 402. Thus, in step 403 the heating engineer assembles the core drill with the appropriate sized bit which in the preferred embodiment of the present invention may suitably have a diameter of 100 mm or 120 mm or 150 mm; these core bit drill sizes are readily bought or hired from tool suppliers. When used in conjunction with a conventional power hammer drill, these core drill bits are able to cut through brick work slowly giving a fairly uniform and tidy cylindrical passage, into which a conventional steel flue can lo be slid. Thus, following step 403 the heating engineer, having assembled the core drill appropriately, places the core drill at the appropriate place on a specified wall of the room and bores through the wall carefully so as to create a cylindrical shaped aperture comprising a hole. Step 404 requires the heating engineer to additionally implement certain safety measures. Thus, for example the heating engineer may be required to attach the core drill to a mechanism configured to prevent the core drill detaching itself from the operator when in use. In this way the drill or parts thereof are prevented from falling out of the outside end of the completed hole. Following step 404 the heating engineer seals and waterproofs the flue aperture created in step 404. This may suitably be achieved via sliding a plastics adhesive liner into the wall or simply sealing the surface of the passage created using a suitable material such as bitumen.

Following step 405 in step 406 the heating engineer is required to insert a flue liner which may suitably be made of steel or a plastics based material. A flue liner is preferred so that a smooth passage-way is created through the wall, through both the internal and external portions of a conventional cavity wall arrangement. Following step 406 in step 407 the heating engineer then inserts a steel cylindrical flue member, which in accordance with the present invention, houses an electro-mechanical fan. The cylindrical flue member with fan inside may be readily pushed into the substantially smooth passageway lined in step 406. The cylindrical flue member may be pushed and slid through the passage so that the fan sits towards the end of the flue member and is located just outside the external surface of the wall. The horizontal flue member 206 may suitably be extended outside the wall by a distance of approximately 100 mm in length so that the fan is effectively located in a position away from the wall. A small distance from the outside edge of the wall is preferred in terms of the positioning of the fan so that any noise generated through vibration of the fan is minimised with resultant low nuisance to the owner of the gas appliance.

Following step 407 the heating engineer may perform a variety of other steps such as fitment of the flue member fitted in step 407 to a connection flue member of the type identified in Figure 3 (member 205). Thereafter, the gas appliance to be fitted can be fitted to the inserted flue arrangement detailed above. Following fitment of a gas fire or another suitable appliance to the flue arrangement, the electric power supplies may be plugged in. As identified in Figure 3 the electric power supply lead 306 configured to deliver electric power to fan 303 may be simply passed along the internal surface of flue member 206 so as to enter the room behind a heat resistant shield located behind gas appliance 201. In the preferred embodiment the domestic mains lead 306 is placed within an internal heat resistant cavity located within member 206, such as a covered channel formed of ceramics based heat resistant material.

The preferred embodiment of the invention as identified above utilises a flue aperture comprising a circular cross section. However, other embodiments may be configured in accordance with the present invention including a flue arrangement comprising a square cross section or some other suitable shape. The fan itself should be able to withstand temperatures of exhaust gases passing from a gas fire and thus in the preferred embodiment is configured to operate at or above temperatures of 2000C. Preferably, the fan is of a type and construction which is able to withstand an environment of exhaust gases passing from a gas fire having a heat output in a range of 10,000 - 30,000 British Thermal Units (BTU's). The equivalent range in SI units is 1.055 x 10 ' J to 3. 165 x 10 'J.

As described above the invention is not to be considered as limited to installing gas fire appliances having power assisted flue arrangements. The invention may equally be used for purposes of installation of domestic or commercial boiler units, for example, and also for a variety of combustion driven appliances. The invention is found to provide many advantages over prior art flue mechanisms and methods of inserting flue arrangements, a further such lo advantage being the fact that the flue arrangement can be inserted through an external wall of a building from the inside of the building. This is in contrast to prior art flue arrangement of the type identified in Figure I wherein the fan and box arrangement must be fitted to the outside of a building wall from the outside. In applications wherein the flue arrangement is to be fitted to a building wall on the first or higher floor of a multi-storey building then fitment of a box and fan arrangement of this type is considered to present a health and safety hazard to the heating engineer fitting the device. The present invention, fitted from the inside of given building, is much safer in that the heating engineer is not required to work on the outside of the building in a position located substantially above ground level.

The embodiments of the invention described herein before are not to be considered as limited to use with heating appliances for buildings. Flue arrangements of the kinds described and envisaged within the spirit of the invention may comprise flue arrangements for use with a wide variety of other appliances and domestic or industrial situations. Thus, for example a flue arrangement configured in accordance with the invention may be suitable for use in extracting hot gases and steam and the like from a cooking appliances such as an oven. Similarly, various industrial situations may comprise extraction of substantially gaseous waste product material, the waste material possibly including a component of particulate matter. Thus, the invention is also considered to lend itself for advantageous use in a wide variety of industrial situations and environments such as chemical plants and factories.

Claims

Claims:

A flue arrangement configurable for use in extracting substantially gaseous waste products ffom a combustion _driven appliance, said flue arrangement comprising:

connection means for enabling connection of said flue to said appliance; passage means configurable for enabling passage of said gaseous waste products awc-o/ from said appliance; and means, located substantially within said passage means, for forcing said gaseous waste products through said passage means.
2. A flue arrangement according to Claim 1, wherein said waste product forcing means is located substantially towards the outside end of said passage means.
I A flue arrangement according to Claim 1 or Claim 2, wherein said waste product forcing means comprises an electro-mechanical fan configured to draw said waste products through said passage means.
4. A flue arrangement according to any preceding claim, wherein said waste product forcing means is electrically powered via mains electricity transmission means configured to pass substantially within said waste product passage means.
5. A flue arrangement as claimed in Claim 4, wherein said electricity transmission means comprises materials configured to withstand temperatures in the range 200'C to 3000C.
6. A flue arrangement according to Claim 4 or Claim 5, wherein said electricity transmission means is contained within a substantially heat resistant structure located within said passage means, said heat resistance being effective in the range 200'C to 3000C.
7. A flue arrangement according to Claim 6, wherein said structure comprises an elongate hollow member configured to cover said electricity transmission means throughout the length of said passage means.
8. A flue arrangement according to any of Claims 1, 2, 3, 4, 6 or 7, wherein said passage means comprises an elongate hollow member having a substantially circular cross section.
9. A flue arrangement as claimed in any of Claims 1, 2, 3, 4, 6, 7 or 8, is wherein said passage means comprises an elongate hollow member having a substantially square cross section.
10. A flue arrangement as claimed in Claim 1 or Claim 3, wherein said waste product forcing means is substantially permanently fixed to said passage 20 means.
11. A flue arrangement as claimed in Claim 1, 3 or 10, wherein said passage means comprises a grid like member positioned transversely to a main length of said passage means, said waste product forcing means being fixed to 25 said grid.
12. A flue arrangement as claimed in any of Claims 1, 3, 10 or 11, wherein said waste product forcing means is operated in response to flow detection means configured to monitor flow of said waste products.
13. A flue arrangement as claimed in Claim 1, wherein said-appliance is a heating appliance configured to heat a portion of a building.
14. A flue arrangement as claimed in Claim 1 or Claim 12, wherein said 5 heating appliance is a gas fire or a gas boiler.
15. A flue arrangement as claimed in Claim 1, wherein said passage means is configured for fitment in an orifice bored through an outside wall of a building.
16. A flue arrangement as claimed in any of Claims 1, 2, 3, 4, 6, 7, 8, 9, 10, 11 or 15, wherein said passage means is additionally configured to position said forcing means substantially on the outside of an outside wall of a building.
17. A flue arrangement as claimed in any preceding claim, wherein said arrangement comprises a fanned balanced flue.
18. A method of installing a flue arrangement in a building, said flue being configurable for use in extracting substantially gaseous waste products from an appliance generating said products through combustion, said method comprising the steps of:

entering a room in which said appliance is to be located and selecting a suitable outside structure for fitment of said flue; from the inside of said room boring a passage through said outside structure; and from said inside of said room, inserting an elongate hollow flue member within said passage, said member comprising means, fitted within said member, for forcing said waste products along said member.
19. A method according to Claim 18, wherein said room is a room located on the first floor or a higher floor of a multi-storey building.
20. A method according to Claim 18, wherein said appliance is a gas fire.
21. A method according to Claim 18, wherein said appliance is a boiler configurable to heat a building or a portion of a building.
22. A method according to Claim 18, wherein said step of boring said passage further comprises the step of:

smoothing the walls of said passage so as to facilitate said subsequent insertion of said flue member via sliding said flue member into position.
23. A method as claimed in Claim 22, wherein said smoothing step comprises insertion of a flue passage liner structure.
24. A method as claimed in Claim 18, wherein said waste product forcing means comprises an electro-mechanical fan.
25. A method as claimed in Claim 18 or 24, wherein said forcing means is electrically powered via a mains lead passed through the inside of said elongate hollow flue member.
26. A method as claimed in any preceding claim, wherein said flue arrangement comprises a fanned balanced flue.
27. A method as claimed in Claim 1, wherein said outside structure 5 comprises a wall of a building.
28. A method as claimed in Claim 18, wherein said member is fitted, following said insertion step, such that said forcing means is positioned substantially outside said outside structure.
29. A flue arrangement as substantially described herein with reference to the accompanying drawings.
30. A method of installing a flue arrangement as substantially described 15 herein with reference to the accompanying drawings.