AU2014202988A1 - Automatic Ignition Wood Heater and Method - Google Patents

Abstract

The present invention relates to an automatic ignition wood heater and method where ignition is achieved in a preferred embodiment by an electrically operated rod element which is protected from damage during loading of the heater and/or combustion of fuel.

Description

Regulation 3.2A AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Automatic Ignition Wood Heater and Method The following statement is a full description of this invention, including the best method of performing it known to us: 1 Title: Automatic Ignition Wood Heater and Method Technical Field [01] The present invention relates to the field of solid fuel heaters, particularly those suitable for burning bulky fuel such as domestic firewood. Background Art [02] Wood heaters are enjoyed as a mode of heating by many people particularly where they live in regions with easy access to firewood. A major disadvantage of having a wood heater as a primary means of heating a home is that it requires some skill and the presence of a person to physically light the fire. [03] When a person returns home in the evening they must locate matches or a lighter, bend over or kneel down, open the door and physically light the fire. In addition, a person has to wait some time for the room to warm up. [04] There have been a number of proposals in the prior art for automatically lighting solid fuel. These include US patent 4649260 in the name of Melis which principally discloses a portable lighting device in the form of an electric hoop element which may be used in a fire grate. [05] US patent 3366102 in the name of Mathis discloses a removably mounted electric log lighter and grate. [06] International patent application WO 2008104012 by inventors GutI and Resch discloses a removable ignition device for lighting solid fuel stoves. [07] US patent 8602020 in the name of Marple discloses an improved fire grate of complex construction which appears to use gas fuelled lighters for ignition. [08] While some of the above proposals may have merit they do not offer a neat and convenient fixed means for automatically igniting a wood heater. 2 [09] The above references to and descriptions of prior proposals or products are not intended to be, and are not to be construed as, statements or admissions of common general knowledge in the art. Disclosure of the Invention [10] In aspect the invention provides a solid fuel heater suitable for burning bulky fuel such as domestic firewood said heater comprising: a) a combustion chamber for burning fuel and associated flue for venting gases; b) a fuel retaining means onto which fuel may be set, for supporting and retaining fuel during initial stages of combustion, at least; and c) an electrically operated ignition means powerable by mains power for igniting fuel said ignition means comprising a heating element and associated wiring; wherein said ignition means is fixed in said heater and the heating element is available for contact with the fuel but protected from damage by fuel during loading of the heater and/or combustion fuel. [11] The term "solid fuel heater" means a heater for solid fuel as distinct from liquid or gas fuel. [12] The term "bulky fuel" refers to ordinary firewood or billets cut by hand or chainsaw and does not include pellet fuel. [13] The term "a fuel retaining means" refers to a surface, platform, grate or the like on which fuel may be placed, cradled or set. In its simplest form this may be the floor of the combustion chamber. In most embodiments however this will be a grate. [14] The term "for supporting and retaining fuel during the initial stages of combustion, at least" refers to the ability of the fuel retaining means to hold the fuel at least at the start of combustion. Where the fuel retaining means is a grate it will be understood that once combustion progresses coals and ashes will fall through. [15] The term "electrically operated ignition means" refers to equipment capable of transforming electricity into heat which ignites the fuel. This feature provides automatic ignition (as distinct from manual ignition) by using mains power to create the heat for ignition. 3 [16] The term "powerable by mains power" refers to the electrically operated ignition means being connectable to, and powered by mains power. [17] The term "heating element" refers to an appliance which converts electricity into heat by passing electric current through a resistive material. [18] The term "associated wiring" refers to the wiring required to supply power to the heating element. [19] The term "fixed" refers to the ignition means not being removable during normal use of the heater. Clearly the ignition means may be removed when maintenance or replacement is required. [20] The invention also relates to a method of remotely igniting fuel in a solid fuel heater suitable for burning bulky fuel such as domestic firewood, said method comprising: providing i) a solid fuel heater with a combustion chamber and associated flue for venting gases, a fuel retaining means for supporting and retaining fuel, an electrically operated ignition means powered by mains power for igniting fuel and comprising a heating element and associated wiring, wherein the ignition means is fixed in said heater and the heating element is available for contact with fuel set on the fuel retaining means but is protected from damage during fuel loading and/or combustion; and providing ii) a switching means for operating the ignition means connected to the mains power; said method comprising the steps of: a) setting fuel on the fuel retaining means in the heater, b) connecting the heater to the mains power via the switching means for operating the ignition means; and c) operating the switching means which results in the fuel ignition means igniting the fuel. [21] Preferably the heating element is sequestered such that only a portion of the element is available for contact with the fuel. [22] Preferably the fuel retaining means comprises a grate having bars with spaces therebetween and the heating element is disposed in one of the spaces. 4 [23] Preferably the heating element is a rod element even more preferably a stainless steel rod element. [24] Preferably the heater includes a ducting means which deflects heat away from at least part of the associated wiring. Even more preferably the ducting means comprise air wash duct plates. [25] Preferably the switching means is an electric plug socket timer connected to the mains power. [26] Even more preferably the switching means is a Wi-Fi enabled switch connected to the mains power controllable by a smart phone, tablet or similar electronic device and method comprising the additional step of sending a message via the electronic device to the Wi-Fi enabled switch which results in operation of the fuel ignition means thereby igniting fuel. [27] Preferably the switching means has an associated safety timer for turning off the flow of mains power when the mains connected switch fails to operate correctly. Brief Description of the Drawings [28] The invention will now be described with reference to the following non limiting illustrative drawings. [29] Figure 1 is a front elevation view of the solid fuel heater according to one embodiment of the present invention. [30] Figure 2 is that back elevation view of the heater in figure 1. [31] Figure 3 is a vertical sectional side elevation view of the heater of figure 1. [32] Figure 4 is a top horizontal sectional view of the heater of figure 1. [33] Figure 5 is an underneath partial perspective view with some features exploded of the front of the heater of figure 1. 5 [34] Figure 6 is an underneath partial perspective view with some of the features exploded off the back of the heater of figure 1. Modes of Carrying out the Invention [35] Wood heater 10 is of basic standard construction fabricated principally of sheet metal with base 20, body 40 and flue 100 as will be known by a person skilled in the art. [36] Where the present invention departs from standard wood heaters is by the provision of electrically operated ignition means 80 and associated features described in more detail below. [37] Base 20 comprises foot 22, pedestal 24, ash chamber 25 and slidable ash pan 26. Ash pan 26 opens at front of wood heater 10. [38] Body 40 is larger than base 20 and comprises bottom wall 41, front wall 42, side walls 43, back wall 44 and stepped top wall 45 which has an opening for adjacent flue 100. Front wall 42 has hinged door 48 opening into combustion chamber 60. Front panel 42a forms part of front wall 42 below door 48. [39] The different dimensions of foot 22, pedestal 24 and body 40 create a recess at the back of heater 10 which provides a convenient location for controls 90 which are mounted on back panel 24a of pedestal 24. [40] Combustion chamber 60 in the form of firebox 61 comprises fuel retaining means 70 in the form of floor 72 made up of fire bricks 74 and grate 76. Firebox 61 also has fire bricks 64 on sidewalls and air wash duct plates 68 adjacent door 48. [41] Room air intake chamber 50 is disposed between back wall 44 and firebox 61 and has an opening at the back of heater 10 which allows air to be taken in from the surrounding environment, heated and expelled from air outlet 55 at the top. [42] Grate 76 comprises a series of parallel bars 76a and adjacent spaces 76b which open into ash pan 26 in ash chamber 25 below. 6 [43] Electrically operated ignition means 80 comprises a heating element 81 and associated wiring 84. The potentially heat sensitive parts of ignition means 80 are protected by element housing 85 which comprises a hollow rectangular sheet metal tube with mounting face plate 85a at one end. Element housing 85 is disposed within an aperture on front panel 42a and screw mounted via mounting face plate 85a. Ceramic wiring block 86 is also screw mounted on front panel 42a. Associated wiring 84 runs from heating element 81 to mounting block 86 into wiring aperture 87 on front panel 42a. [44] Element housing 85 extends into pedestal 24 underneath grate 76. Housing 85 is covered by air wash duct plates 68 inside heater 10. Fascia plate 49 is essentially L-shaped in cross section with a solid upwardly facing wall and a perpendicular perforated leg which bolts to the bottom wall 41 taking it up and out of the way of the ash pan drawer 26. [45] Heating element 81 comprises a rod element 83 which is mounted midway along grate 76 in one of spaces 76b between and level with bars 76a: it is flush with the bars. This sequestering of rod element 83 by the bars results in the element being protected from logs when they are being loaded into heater 10. [46] Rod element 83 is a stainless steel sheathed igniter rod made by WatlowTM or IEC rod elements. For example WatlowTM part J4A90-L12 which is a 240V, 250W or WatlowTM part J4A-15209 which is a 200V, 200W fire rod may be used. Whitfield LennoxTM igniter rods may also be used. [47] Ducting means in the form of air wash duct plates 68 function as baffles to deflect hot air away from wiring 84 and to draw in cool air. Duct plates 68 are made of 5 and 6mm mild steel plate. They create a consistent flow of fresh air that helps keep the igniter element housing 85 cool as well as keeps the wood heater door glass clean by creating a curtain of fresh air past the window. [48] Thus the arrangement provides a neat and convenient way to protect and support the igniter rod inside the firebox. 7 [49] Wires 84 run across front panel 42a as seen on figure 5 inside a conduit in pedestal 24. A steel conduit pipe is welded onto the back of front panel 42a on a downward angle to create a safe passage for the wires to pass from the front of heater 10, through pedestal 24, and then out to back panel 24a where electrical box 92 is mounted. Wires 84 connect to controls 90. Wires 84 are heat resistant and may be silicon, fiberglass or Teflon insulated. Ceramic beads may be used to further protect wires. [50] Controls 90 comprise safety timer 95 housed in heat shielded electrical box 92. Safety timer 95 is a solid-state timer having a one amp electrical load for 10 to 15 minutes and is model THL21200A made by AirotronicsTM. When the 10 to 15 minutes have elapsed, the load de-energizes and the timer re-sets when the power is cut off and the timing cycle restarts when the power is reapplied. [51] Male C16 IEC connector 96 is mounted on heat shielded electrical box 92 and available for connection with mains female C1 6 IEC plug 97 on cable 91. [52] Heat shielded electrical box 92 is screw mounted over composite insulator strips at opening 24b in back panel 24a of pedestal 24. Heat shielding is partly provided by a combination of features including a thin sheet metal plate as seen on figure 6 sandwiched between the safety timer and 5mm thick Bakelite composite strips. The 5mm thick upright Bakelite heat resistant composite strips sandwiched between the thin heat shielding plate and pedestal 24 create a space for a curtain of air that can naturally rise between the heat shielding plate and pedestal. These Bakelite strips also insulate the electrical box from the pedestal to prevent metal contact between the electrical box and the pedestal, also aiding in keeping the electrical box cool. These features allow the safety timer and IEC connector to stay cooler. [53] Cable 91 may be plugged into a standard mains outlet and heater ignition operated from there. Alternatively a commercially available outlet power timer such as IntermaticTM or ArlecTM brands may be used where it is desired to light the heater without being physically present. This allows heater 10 to be ignited at a preset time. 8 [54] As another alternative a Wi-Fi enabled power outlet plug such as the BelkinTM WeMoTM may be used so that heater 10 can be operated remotely by sending a message form an electronic device with the appropriate app. [55] When a piece wood is laid directly on top of rod element 83 in grate 76 and electrical power is applied, rod element 83 becomes red hot and efficiently ignites the wood. The sequestered nature of rod element 83 means that heavy logs which are often mercilessly thrown into a firebox do not damage this element. 9 [57] Table 1 below is a legend for the drawings. Table 1 Reference Feature number 10 Wood heater 20 Base 22 Foot 24 Pedestal 24a Back panel of pedestal 25 Ash chamber 26 Ash pan 40 Body 41 bottom wall 42 Front wall 42a Front panel 43 Sidewalls 44 Back wall 45 Top wall 48 Door 49 fascia 50 Room Air intake 55 Air outlet 60 Combustion chamber 61 Firebox 64 Fire bricks on sidewalls 68 Air wash duct plates 70 Fuel retaining means 72 Floor 74 Fire bricks on floor 76 Grate 76a Bars 76b Spaces 80 Electrically operated ignition means 81 Heating element 83 Rod element 84 Associated wiring 85 Element housing 85a Mounting face plate on housing 86 Ceramic wiring block 87 Aperture for wiring in front panel 90 Controls 91 mains power connection cable 92 Heat shielded electrical box 95 Safety timer 96 male IEC connector 97 Female connector 100 Flue 10 [58] Throughout this specification and the claims that follow, unless the context requires otherwise the words "comprise", "comprises", "comprising" will be understood to mean the inclusion of the stated integer, step or group of integers or steps but not the exclusion of any of other integer, step or group of integers or steps. 11

Claims (17)

1. A solid fuel heater suitable for burning bulky fuel such as domestic firewood said heater comprising: a) a combustion chamber for burning fuel and associated flue for venting gases; b) a fuel retaining means onto which fuel may be set, for supporting and retaining fuel during initial stages of combustion, at least; and c) an electrically operated ignition means powerable by mains power for igniting fuel said ignition means comprising a heating element and associated wiring; and wherein said ignition means is fixed in said heater and the heating element is available for contact with the fuel but protected from damage during loading of the heater and/or combustion fuel.

2. The heater of claim 1 wherein said heating element is sequestered such that only a portion of the element is available for contact with the fuel.

3. The heater of claim 2 wherein said fuel retaining means comprises a grate having bars and spaces therebetween and said heating element is disposed in one of the spaces.

4. The heater of claim 3 wherein said heating element is a rod element.

5. The heater of any one of claims 1 to 4 comprising a ducting means which deflects heat away from at least part of the associated wiring.

6. The heater of claim 5 wherein the ducting means comprises air wash duct plates.

7. The heater of any one of claims 1 to 5 comprising a safety timer for turning off the flow of mains power.

8. A method of remotely igniting fuel in a solid fuel heater suitable for burning bulky fuel such as domestic firewood, said method comprising: 12 FP107CLAIMSAsFiled.docx providing i) a solid fuel heater with a combustion chamber and associated flue for venting gases, a fuel retaining means for supporting and retaining fuel, an electrically operated ignition means powered by mains power for igniting fuel and comprising a heating element and associated wiring, wherein the ignition means is fixed in said heater and the heating element is available for contact with fuel set on the fuel retaining means but is protected from damage during fuel loading and/or combustion; and providing ii) a switching means for operating the ignition means connected to the mains power; said method comprising the steps of: a) setting fuel on the fuel retaining means in the heater, b) connecting the heater to the mains power via the switching means for operating the ignition means; and c) operating the switching means which results in the fuel ignition means igniting the fuel.

10. The method of claim 9 wherein the switching means is an electric plug socket timer connected to the mains power.

11. The method of claim 9 wherein said switching means is a Wi-Fi enabled switch connected to the mains power controllable by a smart phone, tablet or similar electronic device; said method comprising the additional step of c) sending a message via the electronic device to the Wi-Fi enabled switch which results in operation of the fuel ignition means thereby igniting fuel.

12. The method of claim 8 wherein said heater comprises a heating element that is sequestered such that only a portion of the element is available for contact with the fuel.

13. The method of claim 8 wherein said fuel retaining means is a grate comprising bars and spaces therebetween and said heating element is disposed in one of the spaces.

14. The method of claim 13 wherein said heating element is a rod element. 13 FP107CLAIMSAsFiled.docx

15. The method of any one of claims 8 to 14 wherein the heater comprises a ducting means which deflects heat away from at least part of the associated wiring.

16. The method of claim 15 wherein the ducting means comprises air wash duct plates.

17. The method of any one of claims 8 to 16 wherein the heater comprises a switching means with an associated safety timer for turning off the flow of mains power when the switching means fails to operate correctly.

18. The wood heater of claim 1 or the method of claim 8 wherein the heating element is a rod heating element made of stainless steel. Dated this 3rd day of June 2014 Elmendorf Hutterian Brethren Inc By their Patent Attorneys: Tasmanian Patent Services 14