AU2007281757A1 - Backpacking stove - Google Patents

Description

WO2008/019273 PCT/US2007/074987 BACKPACKING STOVE REFERENCE TO RELATED APPLICATION (0001) This patent application claims the benefit of U.S. Provisional Patent Application No. 60/821,522, filed August 4, 2006, and incorporated herein in its entirety. TECHNICAL FIELD OF THE INVENTION (0002) The present invention relates to fuel burning appliances, and more specifically to backpacking and camping stoves. BACKGROUND OF THE INVENTION (0003) Fuel burning camp stoves and lanterns for camping and outdoor use are well known and are described, for example, in U.S. Pat. No. 3,876,364, which is owned by The Coleman Company, Inc., assignee of the present invention. Liquid fuel, which is often used in such camp stoves and lanterns, may be, for example, COLEMAN branded fuel, white gas, unleaded gasoline, or other liquid fuels. (0004) In some conventional liquid fuel camp stoves such as the ones which The Coleman Company, Inc. has offered for many years, fuel is contained in a pressure vessel or - 1 - WO2008/019273 PCT/US2007/074987 fuel tank into which air is pumped under pressure. As described in U.S. Pat. No. 3,876,364, the fuel tank is equipped with a dip tube which extends to nearly the bottom of the tank. The dip tube is closed at the bottom with the exception of a small diameter orifice through which fuel is allowed to enter. The dip tube has an internal conduit which is open at the bottom and which communicates with the upper part of the pressure vessel above the maximum intended fuel level. The dip tube orifice can be partly blocked by insertion of a needle, which is suitably connected to the fuel control system. The needle partly blocks the orifice during the lighting cycle and is removed to leave the orifice unblocked during the normal burn cycle. This partial blockage during the lighting cycle causes air to be drawn down the space between the internal and outer conduits of the dip tube from an opening at the upper part of the pressure vessel. As this air accompanies fuel up the internal conduit, a fuel-lean mixture of fuel and air is created to enhance lighting. A fuel-lean mixture is needed at initial lighting, because the fuel in the mixture is not vaporized and thus must be mixed with a lot of air for combustion. The air-fuel mixture then passes to a generator which is connected to the dip tube by the fuel control system. The generator is a metal tube which passes above - 2 - WO2008/019273 PCT/US2007/074987 the burner of the stove into a venturi assembly which is connected to the burner. The generator is heated by the flame of the burner when the burner is operating. Fuel is discharged at high velocity from an orifice or jet at the end of the generator into the venturi where air is aspirated and mixed and fed to the burner with the air/fuel mixture as a combustible mixture for burning. (0005) After the burner has been operating for an initial period and the generator is sufficiently heated, the fuel that travels through the generator is vaporized. As such, after the generator is heated, the fuel expands and may be supplied in a less lean mixture. At this point, the needle may be removed from blocking of the passage. (0006) In U.S. Pat. No. 3,876,364, the restricting needle is operated by rotating a fuel control knob. In other appliances, a lever is used to adjust the appliance for starting and running. The lever is moved up to start and then down to run. (0007) The foregoing structure for allowing liquid fuel appliances to be lighted when the generator is cold is referred to as an "instant lighting system." Liquid fuel appliances, which do not include an instant lighting system require some other means for heating the generator during start-up, for example, liquid priming fuel, heating paste, - 3 - WO2008/019273 PCT/US2007/074987 or a priming pad typically made of a high temperature ceramic material. In any event, the lighting process requires some form of preheating. (0008) This is true for fuel burning camping and backpack stoves having what is known in the art as an impingement burner. Some such stoves having impingement burners are capable of operating using a number of different fuel sources in addition to the liquid fuels discussed above. In general, such stoves are considered "multi-fuel" camping and/or backpacking stoves. Generally speaking, these multi-fuel stoves can burn liquid fuel, propane, butane, kerosene, and various propane/butane mixtures, among others. (0009) An advantage of the multi-fuel camping and/or backpacking stoves over the above-described liquid fuel stoves centers around the available fuel sources in the region of the world in which the stove will be used. For the adventure camping market, hikers, climbers, and other adventurers typically travel to various remote locations to undertake their next climbing, hiking or other challenge. Unfortunately, the available fuel supply will depend upon what is available in the given locality. Accordingly, a multi-fuel stove is the ideal tool for such enthusiasts. - 4 - WO2008/019273 PCT/US2007/074987 (0010) Existing multi-fuel stoves do, however, have limitations. Because of, among other things, their design and ability to run on multiple fuel sources, the ability to have precise control of the flame and thus the heat output of the stove is limited. In addition, complex fuel tip cleaning systems are generally employed with such multi-fuel stoves. Because of the nature and design of the cleaning systems, adequate cleaning of the fuel tip cannot be achieved unless the stove is turned off, and depending upon the situation, allowed to cool. (0011) What is needed therefore, but presently unavailable in the art is a multi-fuel fuel burning appliance, such as, but not limited to, a camping and backpacking stove, lantern, torch or other device having a fuel tip that can be cleaned while the device is still running. More preferably, such a stove should be designed so that the user can perform this function while the stove is operating and with a bare hand, i.e., without any special protective gear, such as gloves. The control for such functionality should be a component of the stove and not a feature of the fuel tank or fuel supply line or fuel supply valves, but should not significantly increase the size or complexity of the stove. It is to the provision of such a - 5 - WO2008/019273 PCT/US2007/074987 multi-fuel stove that the present invention is primarily directed. -6- WO2008/019273 PCT/US2007/074987 SUMMARY OF THE INVENTION (0012) The following presents a simplified summary of some embodiments of the invention in order to provide a basic understanding of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some embodiments of the invention in a simplified form as a prelude to the more detailed description that is presented later. (0013) In accordance with an embodiment, a burning appliance is provided having a burner assembly including a burner for providing combustion and a fuel tip for supplying fuel to the burner. A fuel control and cleaning assembly may cooperate with the fuel tip to permit control of fuel supplied to the burner and cleaning of the fuel tip while the stove is in operation. (0014) In accordance with another embodiment, a multi-fuel burning appliance capable of running on any one of a number of fuels is provided. The multi-fuel burning appliance includes a burner assembly having a burner for providing combustion and a fuel tip for supplying fuel to the burner. A cleaning assembly is constructed and arranged on the burning appliance to control the amount of fuel - 7 - WO2008/019273 PCT/US2007/074987 supplied to the burner while at least partially cleaning the fuel tip during stove operation. (0015) In accordance with yet another embodiment, a cleaning assembly for a burning appliance is provided. The cleaning assembly is preferably affixed to the burning appliance and may include a cleaning element, a cleaning element control mechanism and a heat dissipating interface positioned with respect to the cleaning element and the cleaning element control mechanism such that a user may control the cleaning element with the cleaning element control mechanism without the use of gloves or other protective gear while the appliance is in operation. (0016) In yet another embodiment, a method is provided for controlling fuel supply through the fuel tip of a multi-fuel burning appliance while facilitating at least partial cleaning of the fuel tip while the burning appliance is in operation. (0017) Other features of the invention will become apparent from the following detailed description when taken in conjunction with the drawings, in which: - 8 - WO2008/019273 PCT/US2007/074987 BRIEF DESCRIPTION OF THE DRAWINGS (0018) FIGURE 1 is a top perspective view of a stove together with a fuel tank in accordance with an embodiment; (0019) FIG. 2 is an exploded, top perspective view of some of the components of the stove depicted in FIG. 1; (0020) FIG. 3A is an exploded side perspective view of the stove depicted in FIG. 1; (0021) FIG. 3B is a side perspective view of the stove depicted FIG. 3A in an assembled expanded configuration; (0022) FIG. 3C is a side perspective view of the stove depicted in FIG. 3A in an assembled collapsed configuration; (0023) FIG. 4A is a side perspective view of the cleaning valve assembly of the stove depicted in FIG. 1; (0024) FIG 4B is an end view of the cleaning valve assembly depicted in FIG 4A; (0025) FIG. 4C is a cross-sectional view of the cleaning valve assembly of FIG. 4B taken along the section lines A - A of FIG. 4A; (0026) FIG. 4D is a partial cross-sectional view of the cleaning valve assembly of FIG. 4C, showing the cleaning - 9 - WO2008/019273 PCT/US2007/074987 element and fuel tip cooperating to provide a low fuel flow state; and (0027) FIG. 4E is a partial cross-sectional view of the cleaning valve assembly of FIG. 4C showing the cleaning element and fuel tip cooperating to provide a high fuel flow state. - 10 - WO2008/019273 PCT/US2007/074987 DETAILED DESCRIPTION (0028) In the following description, various embodiments of the present invention will be described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the embodiments. However, it will also be apparent to one skilled in the art that the present invention may be practiced without the specific details. Furthermore, well known features may be omitted or simplified in order not to obscure the embodiment being described. (0029) Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. An exemplary burning appliance of the present invention is shown in FIG. 1 as a backpacking stove and is designated generally throughout by reference numeral 20. (0030) In the embodiment shown, the stove 20 includes a burner assembly 22 connected by a fuel feed line 24 to a liquid fuel tank 26. The liquid fuel feed line 24 connects to a generator 27, which in turn is connected to a valve assembly, preferably a cleaning valve assembly 28. The generator 27, in a manner known in the art, winds around and over the burner assembly 22 so that it may be heated by a flame produced at the burner, preferably an impingement - 11 - WO 2008/019273 PCT/US2007/074987 burner 30. The generator 27 then extends downward to a bottom of the stove 20 and into one side of the cleaning valve assembly 28. (0031) As configured in accordance with this embodiment of the invention, the generator 27 and/or portion of the cleaning valve assembly 28 must be pre-heated so that fuel supplied through the generator 27 to the cleaning valve assembly 28 will become hot enough to vaporize so that ignition and combustion can occur. As can be seen in FIG. 2, a burner support assembly 32 is positioned below the burner assembly 22, and supports the cleaning valve assembly 28 and a preheating pad 34 located beneath and around the cleaning valve assembly 28. An exit orifice 36 of a fuel tip 38 is located at a top portion of the cleaning valve assembly 28 beneath burner 30 of burner assembly 22. As used herein, a "fuel tip" is the location where fuel leaves the fuel conduit and is released for combustion. In this embodiment, at the exit orifice 36. (0032) The preheating pad 34 is preferably made of a high temperature ceramic material. Prior to lighting of the stove 20, the preheating pad 34 may be saturated with liquid fuel, alcohol or some other fuel source. This fuel source may be ignited and burned to create sufficient heat over several minutes in order to cause at least partial - 12 - WO2008/019273 PCT/US2007/074987 vaporization of the fuel in a portion of the cleaning valve assembly 28 and the generator 27. This vaporization aids in providing the proper fuel and air mixture, which may be discharged through the exit orifice 36, providing fuel for a flame in the burner assembly 22. (0033) Turning now to FIG. 3A, an exploded perspective view of the stove 20 is depicted. The burner assembly 22 including the burner 30 is affixed to the burner support assembly 32, preferably via a treaded connection on the top of the cleaning valve assembly 28 adjacent the fuel tip 38. The burner support assembly 32 is preferably connected to a stove housing 40, to which a plurality of legs 42 are pivotally attached. As shown in FIG. 3C, the legs 42 are thus permitted to be rotated in and out of engagement with the housing 40 so that the stove may be compacted for ease of packing and or transport. FIG. 3B depicts the stove 20 shown in FIG. 3A in an assembled configuration with the legs 42 extended, while FIG. 3C depicts the stove 20 of FIG. 3A in a collapsed configuration with the legs 42 adjacent the housing 40. (0034) The details of the novel cleaning valve assembly 28 are depicted in FIGS. 4A through FIGS. 4E. As depicted in FIG. 4A, the cleaning valve assembly 28 preferably includes a valve housing 44 to which the fuel - 13 - WO2008/019273 PCT/US2007/074987 tip 38 is attached. Positioned within the orifice 36 of the fuel tip 38 is a cleaning element, preferably a cleaning needle 46 (FIG. 4C). The needle 46 may be controlled by rotation of a control lever 48 (FIG. 2), which extends from the valve housing 44 to and out a remote lever housing 50. As shown in FIG. 4B, the lever 48 extends centrally through lever housing 50. (0035) In conventional stoves, all components of the valve assembly are generally made of brass, which is known for its high heat conduction properties. When conventional stoves incorporate cleaning needles in these brass valve assemblies, the valve assembly becomes to hot to handle during stove operation, and thus the cleaning needle cannot be used while the stove is combusting fuel. Because the cleaning needle cannot be used during operation of conventional multi-fuel stoves, it has not been used to control fuel output from the fuel tips of such stoves. Instead, fuel flow and/or pressure has generally been controlled at the fuel tank or fuel cylinder by valves upstream of the fuel supply line. As a result, for these prior art stoves, limited flame and burner control can be achieved, and the stoves are not expected to have significant flame and heat adjustability. (0036) In accordance with an embodiment of the - 14 - WO2008/019273 PCT/US2007/074987 present invention, fine-tuning of flame adjustability is achieved with the use of a novel heat dissipating element, in the embodiment shown in the drawings, a heat dissipating interface 52 positioned between the valve housing 44 and lever housing 50. In an embodiment, the heat dissipating interface 52 is a tubular member made of a low heat conducting material such as, but not limited to, a ceramic material, titanium or preferably stainless steel. As shown in FIG. 4C, lever 48 passes through lever housing 50 through heat dissipating interface 52 and into valve housing 44. (0037) As seen in FIG. 4C, lever 48 preferably has a bent end 54 that cooperates with a cleaning needle housing 56 that houses the cleaning needle 46. The cleaning needle preferably measures between .02 (two-hundredths) and .005 (five-thousandths) of an inch in diameter, and most preferably .009 (nine-thousandths) of an inch in diameter. As shown in FIGS. 4D and 4E, when the lever 48 is rotated, the bent end 54 of the lever 48 takes an eccentric path. During this path, the bent end 54 remains engaged with a notch in the cleaning needle housing 56, and the eccentric path works as a cam in connection with the cleaning needle housing 56 to elevate and lower the cleaning needle 46 within the orifice 36 of fuel tip 38. (0038) By having the bent end 54 engage the notch in - 15 - WO2008/019273 PCT/US2007/074987 the cleaning needle housing 56 instead of the two being a single piece of metal, thermal conduction is limited between the cleaning needle and the lever 48. Thus, heat transfer to the end of the control lever 48 is decreased. (0039) The movement of the cleaning needle 46 within the orifice 36 has at least two functions. First, it cleans deposits from the walls of fuel tip 38 in orifice 36 that are left behind as a result of fuel passage and products of combustion. Second, and as shown clearly in FIGS. 4D and 4E, the cleaning needle 46 changes the amount of fuel flow (as well as other attributes) through orifice 36 as it moves into and out of orifice 36 depending upon the position of the lever 48. (0040) The inside of the fuel tip 38 is preferably necked down and may incorporate one or more gaskets in order to reduce the volume of fuel that may pass through the orifice 36 as the cleaning needle 46 moves up into the fuel tip 38. Generally speaking, the optimum clearance between the cleaning needle and the walls of the fuel tip 38 should be at least about .002 (two-thousandths) of an inch. (0041) The heat dissipating aspects of the present invention are preferably provided by the heat dissipating interface 52. In an embodiment, the entire length of the lever 48 is made from a low heat conducting material such as - 16 - WO2008/019273 PCT/US2007/074987 a ceramic material, titanium, stainless steel, or some combination thereof. The same may also be true for the cleaning needle 46. As a result of the heat from the burner assembly 22, the body of the stove 20 generally runs about 500 to 600 degrees F. If all of the above-mentioned components were made of high heat conducting materials such as brass, the temperature of the end of the lever would be very close to the temperature of the body of the stove 20. In accordance with an embodiment, when the lever 48, the cleaning needle 46, and the heat dissipating interface 52 are all stainless steel and the length of heat dissipating interface 52 is approximately one and one-quarter inches long, the lever housing 50 is approximately two-hundred (200) degrees F and the end of the lever is approximately room temperature when the body of the stove 20 is between five-hundred (500) and six-hundred (600) degrees F and the stove is running. The longer the length of the heat dissipating member 52, the less heat that is transferred to the end of lever 48. One of ordinary skill in the art will recognize that not all of the above-mentioned elements need to be made of low heat conductive material in order to reduce the heat transfer to the end of lever 48. Other combinations or constructions may be equally effective and are intended to be covered by this disclosure. Generally - 17 - WO2008/019273 PCT/US2007/074987 speaking, the length of heat dissipating interface 52 should be at least one (1) cm in length, preferably one (1) inch in length, and most preferably, greater than one and one quarter (1 1/4)inches in length. The increased length itself assists with dissipation as does the additional surface area exposed to ambient air around that surface area. (0042) Other variations are within the spirit of the present invention. Thus, while the invention is susceptible to various modifications and alternative constructions, a certain illustrated embodiment thereof is shown in the drawings and has been described above in detail. It should be understood, however, that there is no intention to limit the invention to the specific form or forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention, as defined in the appended claims. - 18 - WO2008/019273 PCT/US2007/074987 (0043) All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. (0044) The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. The term "connected" is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise - 19 - WO2008/019273 PCT/US2007/074987 indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate embodiments of the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. (0045) Preferred embodiments of this invention are described herein, including the best mode known to the inventor for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. - 20 -

Claims (20)

1. A burning appliance, comprising: a burner assembly having a burner for providing combustion; a fuel tip for supplying fuel to the burner assembly; and a fuel control and cleaning assembly cooperating with the fuel tip to permit control of fuel supplied to the burner, and cleaning of the fuel tip while the stove is in operation.

2. The burning appliance of claim 1, wherein the appliance comprises a stove.

3. The burning appliance of claim 1, wherein the appliance comprises a lantern.

4. The burning appliance of claim 1, wherein the fuel tip comprises an orifice through which fuel is supplied to the burner assembly, and wherein the fuel control and cleaning assembly comprises an object that is movable to vary an amount of blockage of the orifice. - 21 - WO2008/019273 PCT/US2007/074987

5. The burning appliance of claim 4, wherein moving the object cleans an inner bore of the orifice.

6. The burning appliance of claim 5, wherein the object is a cleaning needle.

7. The burning appliance of claim 6, wherein the fuel control and cleaning assembly further comprises a control lever constructed and arranged to cooperate with the cleaning needle such that actuation of the control lever causes the cleaning needle to move to vary the amount of blockage.

8. The burning appliance of claim 7, wherein the fuel control and cleaning assembly further comprises a heat dissipating interface positioned between the control lever and the cleaning needle.

9. The burning appliance of claim 8, wherein the heat dissipating interface comprises a structure between the control lever and the needle, the structure having sufficient heat dissipating qualities to dissipate heat from the burner assembly a sufficient amount so that a user may - 22 - WO2008/019273 PCT/US2007/074987 operate the control lever by direct contact with the control lever.

10. The burning appliance of claim 9, wherein the sufficient heat dissipating qualities comprises the heat dissipating interface comprising at least one of stainless steel, a ceramic material, and titanium.

11. The burning appliance of claim 5, wherein the fuel control and cleaning assembly further comprises a control lever constructed and arranged to cooperate with the object such that actuation of the control lever causes the object to move to vary the amount of blockage.

12. The burning appliance of claim 11, wherein the fuel control and cleaning assembly further comprises a heat dissipating interface positioned between the control lever and the object.

13. The burning appliance of claim 12, wherein the heat dissipating interface comprises a structure between the control lever and the object, the structure having sufficient heat dissipating qualities to dissipate heat from the burner assembly a sufficient amount so that a user may - 23 - WO2008/019273 PCT/US2007/074987 operate the control lever by direct contact with the control lever.

14. The burning appliance of claim 13, wherein the sufficient heat dissipating qualities comprises the heat dissipating interface comprising at least one of stainless steel, a ceramic material, and titanium.

15. The burning appliance of claim 14, wherein the heat dissipating interface comprises a structure that extends around at least a portion of the control lever.

16. A burning appliance, comprising: a burner assembly having a burner for providing combustion; a fuel tip for supplying fuel to the burner assembly, the fuel tip comprising comprises an orifice through which fuel is supplied to the burner assembly; and a fuel control assembly comprising an object that is movable to vary an amount of blockage of the orifice.

17. The burning appliance of claim 16, wherein the fuel control and cleaning assembly further comprises a control lever constructed and arranged to cooperate with the - 24 - WO2008/019273 PCT/US2007/074987 object such that actuation of the control lever causes the object to move to vary the amount of blockage.

18. The burning appliance of claim 17, wherein the fuel control and cleaning assembly further comprises a heat dissipating interface positioned between the control lever and the object.

19. The burning appliance of claim 18, wherein the heat dissipating interface comprises a structure between the control lever and the object, the structure having sufficient heat dissipating qualities to dissipate heat from the burner assembly a sufficient amount so that a user may operate the control lever by direct contact with the control lever.

20. The burning appliance of claim 19, wherein the sufficient heat dissipating qualities comprises the heat dissipating interface comprising at least one of stainless steel, a ceramic material, and titanium. - 25 -