Regulation 3.2 Revised 2198 AUSTRALIA Patents Act, 1990 COMPLETE INNOVATION SPECIFICATION NAME OF APPLICANT CROFTS, Charles William ACTUAL INVENTOR CROFTS, Charles William ADDRESS FOR SERVICE Peter Maxwell and Associates Level 6 60 Pitt Street SYDNEY NSW 2000 INVENTION TITLE: A HEATING SYSTEM FOR A BUILDING DETAILS OF ASSOCIATED PROVISIONAL APPLICATION NO: 2010 903 241 -21 July 2010 -Australia The following statement is a full description of this invention including the best method of performing it known to me: mSNdocs\201E01041\198574.doc 2 A HEATING SYSTEM FOR A BUILDING FIELD OF THE INVENTION The present invention relates to heating systems and more particularly, to a heating system which does not result in the accumulation of negative 5 pressure within the building being heated. BACKGROUND TO THE INVENTION A prior art heating system for a building 10 is shown in Fig. 1. The heating system comprises a fireplace 12 having an adjustable air inlet 14, a flue pipe 16 adapted to channel smoke from the fireplace 12 to outside the building 10 10, and a casing 18 surrounding a portion of the flue pipe 16 which passes through a roof 20 of the building 10. The flue pipe casing 18 is required by Australian Standard No. 2918 and prevents the flue pipe 16 from igniting combustible materials in the roof 20. Heated air inside the building 10 travels up through a bottom opening 22 of the 15 flue pipe casing 18 and out at the top opening 24 of the flue pipe casing 18. The exhaust of heated air from the building 10 via the fireplace 12, adjustable air inlet 14 and the flue pipe casing 18, causes negative pressure inside the building 10 which is equalised through the drawing of air from outside the building 10, via cracks and gaps around windows 24 and doors 26. 20 There are various problems with the prior art heating system of Fig. 1. Firstly, the heated air is prematurely exhausted from the building 10, which increases heating costs. Secondly, the rapid exhaust of heated air creates cold drafts in the building 10, which are uncomfortable for occupants of the building 10. Thirdly, the cold drafts create an uneven distribution of temperature within 25 the building 10, which leads to condensation in cold spots and the formation of mildew and mould. Fourthly, the cold drafts drawn from outside the building 10 contain smoke particles, which reduces the air quality within the building 10. fl7/flnl1 f 3 Accordingly, it is an object of the invention to substantially ameliorate at least some of the problems of the prior art. SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided a 5 duct for retrofitting a heating system of a building, the heating system including a fireplace having an adjustable air inlet, and a flue pipe adapted to channel smoke from the fireplace to outside the building, the duct comprising a (a) an inner casing which surrounds the flue pipe and which defines a first cavity, 10 (b) an outer casing which surrounds the inner casing which defines a second cavity, (c) an inlet channel adapted to channel air from the second cavity to the first cavity and the adjustable air inlet of the fireplace, so that when the duct is installed, the fireplace draws air from outside the 15 building rather than inside the building. According to a second aspect of the present invention, there is provided a method of retrofitting a heating system of a building, the heating system including a fireplace having an adjustable air inlet, and a flue pipe adapted to channel smoke from the fireplace to outside the building, the method 20 comprising, (a) installing an inner casing around the flue pipe to define a first cavity, (b) installing an outer casing around the inner casing to define a second cavity, and (c) installing an inlet duct which connects the second cavity to the first cavity 25 and the adjustable air inlet of the fireplace, so that the fireplace may draw air from outside the building rather than inside the building. n%7Jnnr14 n- 4 In one embodiment of the invention, the method includes the additional step of removing any pre-existing casing which extends over a portion of the flue pipe which extends through a roof of the building. In another embodiment of the invention, the method includes the 5 additional step of extending a pre-existing inner casing which extends over a portion of the flue pipe which extends through a roof of the building, so that the pre-existing inner casing extends to the inlet duct. According to a third aspect of the present invention, there is provided a heating system for a building, the heating system comprising 10 (a) a fireplace having an adjustable air inlet, and (b) a flue pipe adapted to channel smoke from the fireplace to outside the building, (c) an inner casing which surrounds the flue pipe and defines a first cavity, (d) an outer casing which surrounds the inner casing and defines a second 15 cavity, and (e) an inlet duct adapted to channel air from the second cavity to the first cavity and the adjustable air inlet of the fireplace, so that the fireplace may draw air from outside the building rather than inside the building. In a preferred embodiment of the invention, the heating system further 20 comprises (a) an outer casing which surrounds the inner casing, wherein the outer casing has one or more inlet holes; and (b) an air funnel placed over the flue pipe, wherein the air funnel blocks the top of the outer casing and funnels heated air emerging from the first 25 cavity back into the building. It is also preferred that the entrance of the inner casing and the outer casing are protected by weather shields. n 7 I^^f 1A4 A 5 In a preferred form of the invention, the inlet duct channels air around the top plate of the fireplace to the adjustable air inlet of the fireplace, rather than across the top plate of the fireplace. Preferably, the outer casing of the flue pipe is connected via a duct to a 5 range hood of a cook top, wherein air is drawn from outside the building through a vent so that when the cook top and the range hood are in use, air from outside the building is able to pass through the vent to enclose the fumes from the cook top in an air envelope, then to the outer casing and into the fireplace. 10 BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may be readily understood and put into practical effect, reference will now be made to the accompanying drawings, in which: Fig. 1 is a schematic side section view of a building with a prior art 15 heating system installed therein; Fig. 2 is a schematic side section view of a heating system for a building according to a first embodiment of the present invention; Fig. 3 is a perspective partially sectioned view of the heating system of Fig. 2; 20 Fig. 4 is a perspective partially sectioned view of the top of the heating system of Fig. 3; Fig. 5 is a perspective partially sectioned view of the middle of the heating system of Fig. 3; Fig. 6 is a perspective view of a shield for preventing rain from entering 25 the inner casing of the heating system of Fig. 3; Fig. 7 is a ring which supports the shield of Fig. 6 on the flue of a heating system of Fig. 2; 6 Fig. 8 is a spacer which separates the top of the flue from the inner casing of the heating system of Fig. 2; Fig. 9 is a spacer which separates the middle of the flue from the inner casing of the heating system of Fig. 2; 5 Fig. 10 is a perspective view of the shield of Fig. 3, for preventing rain from entering the outer casing of the heating system of Fig. 3; Fig. 11 is a ring which supports the shield of Fig. 10 on the inner casing of a heating system of Fig. 3; Fig. 12 is a spacer which separates the top of the inner casing from the 10 outer casing of the heating system of Fig. 3; Fig. 13 is a spacer which separates the middle of the inner casing from the outer casing of the heating system of Fig. 3; Fig. 14 is a schematic side section view of the heating system of Fig. 2, passing through a roof of a building; 15 Fig. 15 is a perspective partially section view of the bottom of the heating system of Fig. 3; Fig. 16 is a schematic side section view of the fireplace and inlet channel of the heating system of Fig. 2; Fig. 17 is a perspective view of the top plate of the inlet channel of the 20 heating system of Fig. 3; Fig. 18 is a perspective view of the side plate of the inlet channel of the heating system of Fig. 3; Fig. 19 is a perspective view of the base plate of the inlet channel of the heating system of Fig. 3; 25 Fig. 20 is a perspective view of the inlet adaptor of the inlet channel of the heating system of Fig. 3; Fig. 21 is a front view of the inlet adaptor of Fig. 20; nl7n-In 7 Fig. 22 is a rear view of the inlet adaptor of Fig. 20; Fig. 23 is a side view of the inlet adaptor of Fig. 20; Fig. 24 is a perspective view of a heating system for a building according to a second embodiment of the present invention; 5 Fig. 25 is a perspective view of a heating system for a building, according to a third embodiment of the present invention; Fig. 26 is a perspective view of a heating system for a building, according to a fourth embodiment of the present invention; Fig. 27 is a perspective view of a heating system for a building, 10 according to a fifth embodiment of the present invention; Fig. 28 is a perspective view of flue pipe of the fireplace of Fig. 25; and Fig. 29 is a perspective view of a heating system for a building, according to a seventh embodiment of the present invention; Fig. 30 is a top view of the cook top with air outlets of Fig. 29; 15 Fig. 31 is a perspective view of a heating system for a building, according to an eighth embodiment of the present invention; Fig.32 is a perspective view of a heating system for a building, according to a ninth embodiment of the present invention; Fig.33 is a perspective view of a heating system for a building, according 20 to a tenth embodiment of the present invention; Fig.34 is a perspective partial cut-away view of the air funnel of the heating system of Fig. 31; Fig.35 is a perspective view of the air funnel of Fig. 34; Fig.36 is a side view of the air funnel of Fig. 35; 25 Fig. 37 is a perspective partial cut-away view of air inlet holes in the outer casing of the heating system of Fig. 31; 8 Fig. 38 is a perspective partial cut-away view of the inlet channel of the heating system of Fig. 31. MODES FOR CARRYING OUT THE INVENTION Fig. 2 shows a duct 28, according to a first embodiment of the present 5 invention, for retrofitting a heating system of a building 38. The heating system includes a fireplace 30 having an adjustable air inlet 34 (see Fig. 3), and a flue pipe 36 adapted to channel smoke from the fireplace 30 to outside the building 38. The duct 28 channels air from outside the building 38 to the adjustable 10 air inlet 34 of the fireplace 30, so that the fireplace 30 may draw air from outside the building 38 rather than inside the building 38. The duct 40 includes an inner casing 44 which surrounds the flue pipe 36 and defines a first cavity 37, an outer casing 46 which surrounds the inner casing 44 and defines a second cavity 47 and an inlet channel 48 15 adapted to channel air from the second cavity 47 to first cavity 37 and the adjustable air inlet 34 of the fireplace 30. Referring to Fig. 4, the exit of the inner casing 44 is covered by a shield 50 (see Fig. 6), which prevents rain from entering the first cavity 37. The shield 50 is supported by a ring 52 (see Fig. 7) which surrounds the flue 20 pipe 36. The ring 52 is supported by a spacer 54 (see Fig. 8) which separates the flue pipe 36 from the inner casing 44. The spacer 54 has tabs 56 which can be bent over the rim of the inner casing 44 so as to support the spacer 54. Another spacer 58 (see Figs. 3 and 9) rests on a bulge 59 at the slip joint between the upper and lower sections of the flue pipe 36 (see Fig. 5 and 14). 25 Another spacer 54 (see Figs. 8 and 15) has tabs 56 which can be bent over the rim of the inner casing 44 so as to support the bottom of the inner casing 44. nnrkh4 f% 9 The spacer 54 has holes in it, which provide a channel for air to flow up the first cavity 37. The entrance to the outer casing 46 is also covered by a shield 62 (see Fig. 4 and 10), which prevents rain from entering the second cavity 47. The 5 shield 62 is supported by a ring 64 (see Fig. 4 and 11) which surrounds the inner casing 44. The ring 64 is supported by a spacer 66 (see Fig. 4 and 12) which separates the outer casing 46 from the inner casing 44. The spacer 66 has tabs 68 which can be bent over the rim of the outer casing 46 so as to support the spacer 66. Another spacer 70 (see Figs. 5 and 13) rests on a bulge 10 72 at the slip joint between the upper and lower sections of the inner casing 44 (see Fig. 5 and 14). Referring to Fig. 14, the outer casing 46 is attached to a roof 74 of the building 38 using brackets 76 located at the juncture of the roof 74 and the outer casing 46 and stays 78 which extend from the surface of the roof 74 to 15 the outer casing 46. The inlet channel 48 is shown in Fig. 16 and comprises a top plate 80 (see Fig. 17), a side plate 82 (see Fig. 18), a base plate 84 (see Fig. 19) and an inlet adaptor 86 (see Fig. 20) for the adjustable air inlet 34. A front view of the inlet adaptor 86 is shown in Fig.21, a rear view is shown in Fig. 22 and a side 20 section view is shown in Fig. 23. The inlet channel 48 has tabs 88 with screw holes so as to enable the inlet channel 48 to be attached to the opening 90 of the adjustable air inlet 34 (see Fig. 3). Referring to Fig. 3, the adjustable air inlet 34 (as made by the manufacturer of the fireplace 30) comprises a slide 92 located in front of the 25 opening 90. The slide 92 has a series of holes and bars located along it. When the slide 92 is moved in one direction, the series of holes are aligned with the holes in the opening 90, so that the adjustable air inlet 34 is opened. When the /%i7fi fel4k 10 slide 92 is moved in the other direction, the series of bars are aligned with the holes in the opening 90, so that the adjustable air inlet 34 is closed. The adjustable air inlet 34 may be adjusted by gradual movements of the slide 92 to the right or to the left. 5 The method of retrofitting a heating system of Fig. 1 with an duct according to the present invention comprises firstly installing an inner casing 44 (see Fig. 2) around the flue pipe 16 (see Fig. 1). If a casing 18 (see Fig. 1) is already installed, then the casing 18 may be removed altogether and replaced with an inner casing 44 (see Fig. 2). Alternatively, the casing 18 (see Fig. 1) 10 may be extended so that it is the length of the inner casing 44 (see Fig. 2). Secondly, the method comprises installing an outer casing 46 around the inner casing 44. Thirdly, the method comprises installing an inlet duct 48 (see Fig. 2) which connects the outer casing 46 to the adjustable air inlet 14 of the fireplace 12 (see Fig. 1), so that the fireplace 12 may draw air from outside the 15 building 10 rather than inside the building 10. The present invention may comprise a heating system per se, rather than a duct for retrofitting an existing heating system. In such a case, the heating system of the present invention may comprise a fireplace 30 having an adjustable air inlet 34 (see Fig. 3), a flue pipe 36 adapted to channel smoke 20 from the fireplace 30 to outside the building 38, an inner casing 44 which surrounds the flue pipe 36 and defines a first cavity 37, an outer casing 46 which surrounds the inner casing 44 and defines a second cavity 37 and an inlet channel 48 adapted to channel air from second cavity 37 to first cavity 37 and the adjustable air inlet 34 of the fireplace 30. 25 Fig. 24 shows another embodiment of the invention, duct 29, wherein the inlet channel 49 travels around the top of the fireplace 30 to the adjustable air inlet 34 (rather than across the top of the fireplace 30) so that a top surface 93 nt I^ A. a 11 of the fireplace 30 may be used to heat cooking implements, such as a fry pan (not shown). Fig. 25 shows an duct 94, according to another embodiment of the present invention, for retrofitting a heating system of a building 96. The heating 5 system includes a fireplace 98 having an adjustable air inlet 100, a flue pipe 101 adapted to channel smoke from the fireplace 98 to outside the building 96. The duct 94 includes an inner casing 102 surrounding a portion of the flue pipe 101 which passes through a roof 103 of the building 96 (see Fig. 28) and defines a first cavity 105 and an outer casing 104 which surrounds the 10 inner casing 102 and defines a second cavity 106. Referring to Fig. 27, air 108 enters the outer casing 104 then is drawn down the second cavity 106 between the outer casing 104 and the inner casing 102 to the blocking plate 110. The spacer 54 (see Fig.8 and 28) has tabs 56 which can be bent over the rim of the inner casing 102 so as to support 15 the bottom of the inner casing 102. The spacer 54 has holes in it, which provide a channel for air to flow up the first cavity 105. The flue pipe 101 heats the air in the first cavity 105, so that the air travels upwards within the first cavity 105 drawing further air into the second cavity 106. The duct 94 channels air from outside the building 96 to the adjustable 20 air inlet 100 of the fireplace 98, so that the fireplace 98 may draw air from outside the building 96 rather than inside the building 96. The duct 112 may comprise a plurality of discrete duct sections, including an outdoor channel 114 adapted to channel air from outside the building 96, and an indoor channel 116 adapted to channel air from the outdoor 25 channel 114 to the adjustable air inlet 100 of the fireplace 98. The outdoor channel 114 of the duct 112 may be connected to the wall 118 of the building 96 (see Fig. 25), or the floor 120 of the building 96 (see fl7AQ/ll n 12 Fig. 26). Alternatively, the duct 112 may comprise an outdoor channel 114 which connects directly to the adjustable air inlet 100 of the fireplace 98 (see Fig. 27). Fig. 29 shows another embodiment of the invention, heating system 128, 5 wherein an outer casing 130 of a flue pipe 132 is connected via a duct 134 with a flow control valve to an exhaust vent 136 of a range hood 137 for a cook top 138 (see Fig. 30). When an air control valve 141 is opened, air will be drawn into the outer casing cavity 130 from the range hood 137 instead of the outer casing inlet 139. This will draw air from a duct 140 from beneath a floor 142 of 10 a building 144. When the cook top 138 and the range hood 137 are in use, air from outside the building 144 is able to pass through the duct 140 to air outlets 145 around the cook top 138, then into the range hood 137. This will enclose the fumes from the cook top 138 in an air envelope to assist in the reduction of pollutants entering the building 144, thus improving indoor air quality. When the 15 air control valve 141 is closed, the air will be drawn from the outer casing inlet 139. Thereby, a fireplace 146 of heating system 128 is able to draw air from outside the building 144 rather than inside the building 144. Fig. 31 shows another embodiment of the invention, a heating system 148 for a building 150. The heating system 148 comprises a 20 fireplace 152 having an adjustable air inlet 154, and a flue pipe 156 adapted to channel smoke from the fireplace 152 to outside the building 150 (see Fig. 32), an inner casing 158 which surrounds the flue pipe 156 and defines a first cavity 157 and an outer casing 160 which surrounds the inner casing 158 and defines a second cavity 163. 25 The outer casing 160 of has six equidistant holes 164 (see Fig. 37) of approximately 65 mm in diameter. The holes 164 are covered by a shield 166 which prevents rain from entering the outer casing 160. The shield 166 may be nYfaah4 a 13 affixed to the outer casing 160. The holes 164 are positioned at a sufficient height from a roof 166 of the building 150 so as to avoid the ingress of rain bouncing back from the roof 166. Referring to Fig. 32, cool air from outside a building 150 passes through 5 the holes 164 and down the second cavity 163. As shown in Fig. 38, the inner casing 158 is supported by a spacer 168 which allows the passage of air therethrough. The flue pipe 156 heats the air in the first cavity 157, so that the air travels upwards drawing further air into the second cavity 163 via the holes 164 in the outer casing 160. 10 The heating system 148 further comprises an air funnel 170 (see Figs. 34, 35 and 36) placed over the flue pipe 156, wherein the air funnel 170 blocks the top of the outer casing 160 and funnels heated air emerging from the first cavity 157 back into the building 150. The air funnel 170 has a circular aperture 172 so that it may be placed around the flue pipe 156. A bottom panel 15 174 of the air funnel 170 blocks the top entrance to the outer casing 160. The air funnel 170 funnels the air emerging from the first cavity 157 through a nozzle 176. An insulated pipe 178 may be attached to the nozzle 176 to channel the air into a living space 180 of the building 150 (as shown in Fig. 32) or to be ducted through the roof space 182 to other parts of the building 20 150 (as shown in Fig. 33). The heating system 148 may have an inlet channel 184 which channels air around the top of a fireplace 152 (see Figs. 31 and 38) or an inlet channel 186 which channels air across the top of the fireplace 152 (as shown in Fig. 32 and 33) to the adjustable air inlet 154 of the fireplace 152, so that the 25 fireplace 152 may draw air from outside the building 150 rather than inside the building 150.
14 Various modifications can be made in the present invention without departing from the scope of the present invention. The person skilled in the art will appreciate that the invention has application outside that of heating devices. f71fl0n r%