AU728563B3 - Improvements in or relating to heating appliances - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990

ORIGINAL

COMPLETE SPECIFICATION PETTY PATENT Invention Title: Name of Applicant: IMPROVEMENTS IN OR RELATING TO HEATING

APPLIANCES

KENNETH JOHN EGAN The following statement is a full description of this invention, including the best method of performing it known to me: 2 IMPROVEMENTS IN OR RELATING TO HEATING APPLIANCES The present invention relates to improvements in or modifications to heating appliances and to methods of installing such heating appliances, particularly heating appliances used within structures such as buildings. More particularly, the present invention relates to improvements in solid fuel heaters, such as for example slow combustion heaters, and to methods of installing such heaters. The present invention is particularly directed to improvements in solid fuel slow combustion heaters of the type having an outer casing or cabinet for directing air flow around the periphery of the heater, and to a method of installing such improved heaters, particularly in domestic dwellings, such as, for example, when constructing a fireplace or similar enclosure for housing the heater where previously there had been no fireplace, heater or enclosure when installing the heater.

Although the present invention will be described with particular reference to one form of a domestic heater and one method of installing the heater in a domestic dwelling, it is to be noted that the scope of the present invention is not restricted to the described embodiment, but rather the scope of the present invention is more extensive so as to include other arrangements of the heater, other methods of installing the various arrangements of the heaters, and to other applications of the invention, including installations in other environments.

\\mclbjfiles\homeS\Sigrid\keep\patents\petty-PP7482-egan.doc 2/12/99 3 One problem associated with installing solid fuel heating appliances in buildings, such as domestic dwellings, is that the fireplaces for enclosing the solid fuel heaters, slow combustion heaters or the like require the construction of a brick or masonry structure, such as a fireplace, to provide sufficient insulation for the heating appliance to protect the surrounding environment from radiant heat, so that surrounding parts of the building do not become overheated with the attendant risk of smouldering, catching fire or combusting, resulting in injury to people and causing damage to property. In the past, building regulations of the local authorities, such as for example Australian Standard AS 2918 entitled "Domestic solid fuel burning appliances installation" (hereinafter referred to as "the Code"), which prescribe the requirements for installing solid fuel burning heaters, have required that a brick or masonry structure, such as a fireplace or other enclosure, be built to house or enclose the heating appliance when installing the heater. The building of the masonry or brick structure was particularly required when renovating or refurbishing houses where previously no fireplace or suitable enclosure existed.

Whilst the construction of fireplaces or similar from bricks and the like was desirable from a safety point of view, it caused a number of problems and disadvantages.

Some disadvantages of making the masonry or brick structure included the extra cost of materials and the extra time needed to build the fireplace, as well as having to strengthen the floor area upon which the brick or masonry fireplace was constructed. In addition, it was necessary to build a hearth or floor protector area upon which the heater could be located to protect the floor of the lb.f i es\home$\Sigrid\keep\patents\pet ty-PP7482 -eg.doc 2/12/99 4 dwelling from the effects of radiant heat emanating from the heater. All of these disadvantages added to the cost of providing the new fireplace. In many instances, the floor had to be reinforced only because of the need to take the weight of the masonry or brick structure, i.e. but for the masonry or brick structure, the floor would not have had to be reinforced, as it was inherently strong enough to take the weight of the heater. This added to the cost and time taken to construct the new fire place and heating arrangement.

Further, because of the weight of the masonry or brick structure and the brick hearth, it was often not possible to construct fireplaces in the upper storeys of two- or multi-storey houses. This reduced the flexibility of renovating or refurbishing such houses and reduced the number of locations at which the new heater could be installed.

Owing to the possibility that heat-sensitive material in the vicinity of the new fireplace could be affected by excessive radiant heat, there are stringent regulations governing the construction of new fireplaces and the installation of new heaters. The Code is one example of these regulations. The need for such regulations was in part brought about because of the construction and arrangement of the actual appliance which allowed excessive heat to be radiated to the close surroundings which in turn caused them to become hot, sometimes excessively hot.

Previously, such heaters and heating appliances radiated or convected excessive heat, particularly from their top surface, due to the presence of heated air and flue gases exiting the firebox of the heater being in direct contact \\me bf i es\homeS\Sigrid\eep\patent\ptty-PP74 82 -eg .doc 2/12/99 5 with the outer surfaces of the heater. Owing to this, there needed to be a relatively large clearance or air gap between the hot surfaces of the heater and the heatsensitive material from which the remainder of the fireplace was constructed, such as for example the timber framework or surround. The presence of the brick or masonry structure shielded any heat-sensitive material from the excessive heat.

It is to be noted that heat-sensitive material includes within its scope materials which can be affected by heat with the potential to combust when heated by radiant or convected heat. Non-limiting examples of such materials include timber, boards, panels, sheets or the like. Heatresistant materials are materials which are not primarily at risk of combusting when exposed to radiant or convected heat. Such materials include metals, particularly iron and steel, bricks, concrete, mortar and the like. However, it is to be noted that heat-sensitive material includes substitutes for such materials, such as for example steel studs, lintels, cross-members and the like being used in place of conventional timber framing. The steel framing members can include box sections, channel sections or the like. Another example includes the substitution of cement sheet, villaboard or the like for plasterboard.

Furthermore, the Code required that it was necessary to line or cover the heat-sensitive material with heatresistant material, such as for example cement sheet or AC sheeting or similar, on the side facing towards the heater, to protect the heat-sensitive material from becoming too hot. Including layers or covering of heat-resistant material added to the cost of constructing the fireplaces.

\\melbfileas\home$\Sigrid\keep\patents\petty-PP7482-egan. doc 2/12/99 6 Therefore, there is a need for a heater or heating appliance which does not radiate or convect excessive heat to its immediate surroundings, so that the immediate surroundings, particularly the heat-sensitive materials, are not subjected to excessiveheat, and so that insulation material is not required around the heat-sensitive materials, thereby permitting reduced clearance between the heater and the remainder of the fireplace and/or fireplace structure. It is to be noted that the present invention also includes the use of a fireplace insert or other heater insert to overcome the problems of excessive radiant heat.

Furthermore, because of the weight of the masonry structure it was necessary to reinforce the floor area, and because of radiant or convected heat emanating from the base of the heater it was necessary to provide a fire-resistant hearth or floor protector, typically of bricks or masonry, to protect the floor. Providing the brick or masonry hearth or floor protector added further to the weight of the installation, to the cost of building the fireplace, and to the length of time taken to construct the fireplace, particularly as it required at least an overnight period for the masonry or brick structure to dry or set before further work could be commenced. Therefore, there is a need to provide a heater or heating appliance which has better heat-insulating characteristics and a method of installing the heater or heating appliance which does not require the construction of a masonry or brick structure around the heater and/or does not require the construction of a thick or heavy hearth, particularly a hearth of brick or masonry, underneath the heater.

Therefore, it is an aim of the present invention to provide \\mlb.files\homS\Sigrid\keep\patents\petty-PP7482-egn.doc 2/12/99 7 an improved heater or heating appliance and to provide an improved method of installing the heater or heating appliance, which obviate the need to construct a heavy masonry or brick structure and/or to provide a heatresistant hearth from brick or heavy masonry materials underneath the heater.

According to one aspect of the present invention there is provided an improved heater or heating appliance including a firebox and an outer housing or casing generally spaced apart from the firebox at least over a portion of the perimeter of the firebox to form an insulating layer or space between the firebox and the casing or housing for reducing the amount of radiant and/or convected heat emanating from the firebox to the outside of the outer housing or casing, thereby allowing a reduced clearance between the heater and heat-sensitive material located in the vicinity of the heater, particularly heat-sensitive material used in the construction of a fireplace or similar enclosure for the heater.

According to another aspect of the present invention there is provided an improved method of installing a heater or heating appliance without the need to construct a fireresistant structure or enclosure for containing the heater comprising forming a base for supporting the heater, locating the heater upon the base and substantially enclosing the heater in a structure of substantially heatsensitive material, wherein the gap or space between the heater and the heat-sensitive material is reduced or eliminated, thereby eliminating the need for constructing a fire-resistant structure to enclose either wholly or partially the heating appliance.

\\mclb. files\home\Sigrid\keep\ptents\petty-PP7482-eg .doc 2/12/99 8 Typically, the fire-resistant materials include components made from metals, bricks, masonry and the like.

Typically, the heater or heating appliance of the present invention is a solid fuel heater. More typically, the solid fuel heater is a slow combustion heater in which wood, briquettes or like solid fuels are used. Typically, the heater is provided with primary air control, either fully controlled air flow or partially controlled air flow or similar, to control the rate of combustion, particularly to slow the rate of combustion.

Typically, the heater is provided with one, two, three, four or more housings or casings. More typically, the housing or housings in which the firebox of the heater is enclosed is/are made from heat-resistant material, such as for example sheet-metal material. More typically, the sheet-metal material is galvanised iron or similarly treated steel material, such as colorbond steel or the like. Even more typically, the upper surface of the housing is provided with a cut-out for receiving a flue or similar to allow combusted gases to exit from the firebox of the heater.

Typically, the housings are spaced apart from each other to define gaps, spaces, channels or the like therebetween, and from the firebox of the heater also to define spaces therebetween. More typically, the upper surface of the housing or casing is spaced apart from the top surface of the firebox the same or a greater distance than the side walls or back of the casing or housing are spaced from the corresponding side walls or back of the firebox. More \\melbfiles\home$\Sigrid\keep\patents\petty-PP7482-ega.doc 2/12/99 9 typically, the gap at the top of the firebox is greater than the side or rear gaps.

Typically, insulating material is located in the space or gap between the firebox walls or top and the corresponding walls or top of the casing or housing. More typically, the insulation is located between the walls of the intermediate casing(s) or housing(s) and the outer casing or housing.

Even more typically, the insulation is air or other suitable material, such as for example fibreglass, rock wool, glass wool or the like. Even more typically, insulation is provided between the walls or tops of intermediate housings or casings. Even more typically, different types of insulation, including air gaps or spaces, are used in combination with one another.

Typically, the firebox and intermediate housing or casing is the same as or similar to the heater described in Australian Patent Specification No. 74262/94 which is incorporated herein by reference.

Typically, the outer casing or housing encloses five sides of the firebox so that only the front of the firebox is not covered by the casing or housing. More typically, the firebox is located in spaced apart relationship from the outer housing or casing by suitable supports. Typically, the supports are located between the floor of the firebox and the floor of the outer casing or housing. More typically, the supports are feet or similar Typically, the temperature of combustion within the firebox of the heater of the present invention is greater than \\melb iles\home$\Sigrid\keep\patents \petty-PP482-eg doc 2/12/99 10 about 500 0 C, more typically greater than about 600 0 C, and even more typically greater than about 700 0 C, with temperatures being as high as from about 1000-1300 0

C.

Thus, the heat of combustion of the heater of the present invention is from about 500 0 C to 1300 0 C inclusive of all temperatures in between. It is to be noted that as the heater of the present invention is particularly adapted for use with solid fuel materials and more particularly a slow combustion heater, the heat of combustion of such materials is relatively higher than the heat of combustion of alternative fuels, such as oil, gas, or solid fuel such as firewood and the like when used in open fireplaces because combustion which takes place in open fireplaces is not slow combustion but rather is regarded as fast combustion, so that the temperatures in open fireplaces are typically below about 500 0 C or similar. It is to be noted that the temperatures of combustion of the heater of the present invention are higher than the normal temperatures of combustion of wood-burning or other solid-fuel burning open fires or the like. It is this increase in combustion temperature of slow combustion heaters that is the reason for needing a larger gap and heat-resistant materials in the enclosures for such heaters.

Typically, fireplaces made in accordance with the present invention are lighter in weight than conventional fireplaces or fireplaces having masonry or brick structures and/or heavy masonry or brick hearths, so that the fireplace structures of the present invention are relatively lightweight. More typically, because of the light weight of the structures, fireplaces may be constructed in the upper storey or storeys of buildings, \\le~bfi es\h.,c\ Sigrid\keep\patent\ptty- Pp7482 -eq .doc 2/12/99 11 which contributes significantly to the design flexibility when using the heaters and methods of installing the heaters in accordance with the present invention.

The present invention will now be described by way of example with particular reference to the accompanying drawings in which: Figure 1 is a schematic side sectional view of one embodiment of the improved heater of the present invention shown in situ within a fireplace or enclosure built from heat-sensitive material; Figure 2 is a schematic side sectional view of a heater in accordance with the present invention showing the support frame of heat-sensitive material upon which the heater is located in more detail.

One embodiment of the improved heater of the present invention is shown in Figure i. In essence, the firebox of the heater is at least substantially enclosed within a housing or cabinet so that there is an air gap or air clearance between the outer surface of the firebox and the inner surface of the walls of the outer housing or outer cabinet or of an intermediate housing. Optionally, there is also a gap between the outer walls of an intermediate housing or casing and the inner walls of the outer housing or casing, resulting in a dual air gap or space arrangement, in order to provide greater insulation and to reduce the amount of radiant and/or convected heat emanating from the outer wall surfaces of the outer housing or cabinet to the immediate vicinity of the heater. The air gaps or spaces may be filled optionally with suitable \\elb-f ie\home$\Sigrid\kep\patent \ptty-PP74 82eg.doc 2/12/99 12 insulating material, such as rock wool, fibreglass or similar.

Referring to Figure 1, a slow combustion solid fuel heater 2 is shown comprising a firebox 4 having a flue exit 6 located in the top surface of the firebox 4. A door 8 is located at the front of the firebox 4 to allow solid fuel such as wood, briquettes or the like to be inserted into the lower section of the firebox 4 and ignited for combustion within the firebox. The door 8 includes a window so that the fire can be viewed without opening the door. The slow combustion heater 2 further includes an intermediate casing 12 spaced from and around five sides of the firebox 4 to form air channels, gaps or spaces 14 therebetween. Walls of casing 12 correspond to the walls of the firebox. The air channels 14 have an entrance 16 located long the bottom edge of the front of heater 2 below the door 8 and an air channel exit 17 located at the top front of the heater 4 above the door 8. A fan 18 is provided within and at the entrance 16 of the air channel 14 to assist in forcing air along the air channels around the firebox and out of exit 17. This air flow results in hot or warm air flowing into the room in which the heater is located and aids considerably in the efficiency of the heat.

The firebox 4 further includes primary air inlets 20 in the form of a series of apertures extending transversely across the front of the heater 2 above the door 8. Directional plates 22 are located behind the primary air inlets 20 and within the firebox 4 to direct air entering through the primary air inlets 20 downwards along the inside of the door 8 to the lower section of firebox 4. A layer of \\melbf iles\homeS\Sigrid\keep\patents\petty-PP7482-egan.doc 2/12/99 13 refractory bricks or blocks 24 extends around a portion of the lower section of the firebox 4.

An outer housing 30 also comprising five sides encloses the heater 2 on all sides apart from the front surface of the heater having the door 8. The outer housing 30 may be made from any suitable material, such as for example sheet metal material. Heater 2 is supported on metal supports 32 in the form of feet located at spaced apart locations between the base of the firebox 4 and the base of housing 30. An air gap 34, which is formed between the outer walls of intermediate casing 12 and the inner walls of outer housing acts as an insulating layer to reduce the amount of heat being radiated from the heater 2. The air gap 34 may be filled optionally with insulating material such as rock wool 36 or similar.

A timber framework is constructed to form the fireplace or enclosure, including upright 40 made of timber extending substantially vertically and a transverse framework member 46 extending horizontally in line with the front surface of the heater 2. A sheet of fire-resistant material in the form of cement sheet 48 or similar is retained in place in a substantially vertical orientation by the top edge of housing 30 and transverse framework member 46.

This arrangement allows heat sensitive material or substitute material to be located closer to the outer walls of heater 2, without being exposed to excessive heat or without there being a risk of damage to this material from radiant or convected heat since there is less chance of this material being heated excessively. In fact, owing to the insulating properties of having the outer housing \\mlb.file\homeS\Sigrid\keep\patents\petty-PP1482-ega.doc 2/12/99 14 insulating air gap 34 and rock wool layer 36, it is possible for there to be reduced clearance between the outer surfaces of the outer housing 30 and other materials, such as heat-sensitive material, used in the construction of the fireplace, such as for example the framework members 46 in the form of wall studs, noggins, supports and the like. However, if required, a layer of heat-resistant material can be located adjacent the outer casing 30 to provide further insulating against the effects of radiant or convected heat and to reduce the chances of damage to the materials forming the fireplace construction.

At the base of heater 2, there is provided a steel frame which can take a variety of forms. The steel frame replaces the heavy masonry or brick hearth upon which previously available heaters were required to be located.

One form of the steel frame 50 includes a layer of cement sheet attached to the steel framework as shown in Figure 1.

Another form of the steel frame 50 as shown in Figure 2 comprises a sandwich-like construction in which there are two layers of cement sheet 52, 54 attached to a metal framework 56 which defines an air gap within the sandwichlike construction. The metal framework can take any suitable form, such as being made from box section tubing, or channel section tubing, such as C-shaped tubing, or the like.

One example of the lightweight hearth or floor protection that can be used with the improved heater of the present invention comprises two layers of cement sheet 62, 64 forming a base upon which a layer of tiles 66 can be laid to form the lightweight floor protector 60 or hearth in front of the heater 2.

\\melbf iles\home$\Sigrid\keep\patents\petty-PP74 2 -egf .doc 2/12/99 15 In use of the improved heater of the present invention, solid fuel in the form of wood, briquettes or the like is located in the lower section of the firebox 4 and once ignited the door 8 is closed. Primary air enters through the primary air inlets 20 and has been preheated along its path before it passes along the inside of the door 8 to the lower section of the firebox to allow combustion of the solid fuel to occur, thus producing heat. Air circulating in space 14 is thus heated and exits from the heater through outlet 17 to warm the room in which it is located.

Radiant and/or convected heat then passes from the firebox 4 through space 14 and through the walls of intermediate casing 12. The space 34 formed by outer housing 30 acts as a further barrier to radiant and/or convected heat so that the amount of heat emanating from casing 30 is reduced.

Insulation layer 36 further reduces heat transfer to the outside of the heater 2.

Installation of the improved heating appliance of the present invention will now be described. Firstly, where it is intended to construct a new fireplace or similar, modification is made to the room in which the heating appliance is to be installed, such as, for example, by removing the carpet covering the floor or similar. Once the general outline of the new fireplace has been decided upon and the room prepared, the base of the new heating appliance is manufactured. Typically, the base comprises a substantially rectilinear frame made out of a number of lengths of steel tubing interconnected together at their respective ends. However, it is to be noted that the frame can be made from any suitable material and in any suitable shape and can have any suitable configuration.

\\lelbfiles\homeSSigrid\keep\patents\petty-PP7482-eq.doc 2/12/99 16 Typically, the metal tubing is of substantially square or rectangular cross-section and is provided with internal cross-members for added strength, rigidity and support. A layer of suitable heat-resistant material 52, 54 is attached to either surface of the metal framework to form a sandwich-like construction, such as that disclosed in Figure 2. Typically, the heat-resistant material is AC sheeting, cement sheeting or the like. The sheeting may be adhered to the metal framework by the application of adhesive between the individual frame members and one side of the sheet, or may be attached by suitable fasteners.

The base 50 of heat-resistant material acts as the hearth of the conventional fireplace as well as the base for the appliance and also as protection for the floor underneath and immediately in front of the heater, and therefore no additional construction of a heavy masonry or brick hearth beneath the heater 2 is required, thereby providing a saving in time, materials and cost.

A heating appliance 2 in accordance with the present invention as described previously is placed on the base of heat-resistant material. The heating appliance of the present invention has an external cabinet arrangement enclosing the firebox of the heater as described previously. The external cabinet is spaced apart from the firebox to assist in providing a layer of insulation around the firebox. A frame or similar of fire-sensitive material, such as for example comprising framework members 46, is constructed around the heating appliance at predetermined distance from the heating appliance, such as for example at a reduced clearance, particularly at a reduced clearance as compared to that required under the Code. In this manner, no brick or masonry structure is \\melb-files\home$\Sigrid\keep\patents\petty-PP7482-ega .doC 2/12/99 17 required, yet a safe and well-presented fireplace and enclosure can be built in a minimum of time and at a saving of materials, since it is not necessary to wait for the mortar, grout or similar adhesive to dry or cure, which usually occurs overnight or during the next day, which delays completion of the job.

After framing is complete, a suitable covering such as villaboard, plasterboard, or the like is attached to the framework members to fully enclose the heater and to form the fireplace. The covering and framework are made in accordance with the Code in order to satisfy all of the building regulations. Finally, a tiled floor protection comprising cement sheet layers 62, 64 and tiles 66 is formed in front of heater 2 in accordance with requirements of the Code and to provide a lightweight and pleasing finish to the fireplace and enclosure.

The heating appliance of the present invention can include a fireplace insert or similar which can simplify installation as the heating appliance is provided as a unit for direct installation in situ, including having an integral floor protector.

Another embodiment of the present invention includes a heating appliance which is raised off the floor or is provided with a clearance gap or similar underneath the heating appliance.

Advantages of the present invention include the following: There is no need to build a fire-resistant structure such as a brick or masonry enclosure; \\melbfiles\homeS\Sigrid\keep\patents\petty-PP7482-egan.doc 2/12/99 18 The heating installation is relative lightweight; The heating installation is capable of withstanding combustion temperatures in excess of 1000'C; There is no need for a fire-resistant base or hearth made from heavy masonry or brick; Designs for renovating houses or installing new fireplaces are more flexible.

The complete installation of the heater can occur in a minimum of time, such as for example within a single day, as there is no need to wait for the brickwork or masonry to set.

The described arrangement has been advanced by explanation and many modifications may be made without departing from the spirit and scope of the invention which includes every novel feature and novel combination of features hereindisclosed.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is understood that the invention includes all such variations and modifications which fall within the spirit and scope.

\\melb_files\home$\Sigrid\keep\patents\petty-PP7482-egan.doc 2/12/99

Claims (2)

1. 2. A method according to claim 1 in which the heating appliance is provided with an intermediate housing \\melb-files\home\PClarke\Keep\Retypes\63065-99 Kenneth Egan.doc 15/11/00 20 defining a dual gap arrangement between the wall of the firebox and the outer casing and a air flow control means for controlling the flow of air in the space formed between the intermediate housing and the firebox wall, such that the air flow assists in reducing the amount of radiant heat emanating from the outer casing thereby further eliminating the need for a brick or masonry enclosure for the heating appliance.
2. 3. A method according to claim 1 or 2 in which the base includes a metal frame work arrangement and a sheet material attached to the metal frame work defining an air gap between the sheet material and the floor of the building in which the heating appliance is being installed to further reduce the need to construct a brick or masonry enclosure for the heating appliance. Dated this 15th day of November 2000 KENNETH JOHN EGAN By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia \\melb_files\homeS\PClarke\Keep\Retypes\63065-99 Kenneth Egan.doc 15/11/00