Abstract:
A burning appliance having a burner assembly including a burner for providing combustion is disclosed. The appliance includes 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 appliance is in operation. The cleaning assembly may be formed on the appliance itself and may incorporate 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 equipment while the appliance is in operation.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The present invention relates to fuel burning appliances, and more specifically to backpacking and camping stoves. 
       BACKGROUND OF THE INVENTION 
       [0002]    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. 
         [0003]    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 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 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. 
         [0004]    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. 
         [0005]    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. 
         [0006]    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, or a priming pad typically made of a high temperature ceramic material. In any event, the lighting process requires some form of preheating. 
         [0007]    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 on a number of 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. 
         [0008]    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. 
         [0009]    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. 
         [0010]    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 specifically, what is needed is a multi-fuel device having a cleaning needle or other element that functions to both clean the fuel tip and control the fuel path, thus providing flame and heat control at the burner. More preferably, such a stove should be designed so that the user can perform both of these functions 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 multi-fuel stove that the present invention is primarily directed. 
       SUMMARY OF THE INVENTION 
       [0011]    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. 
         [0012]    In accordance with an aspect of the invention, 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 assembly. 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. 
         [0013]    In accordance with another aspect of the invention, 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 assembly. A cleaning assembly is constructed and arranged on the burning appliance to control the amount of fuel supplied to the burner while at least partially cleaning the fuel tip during stove operation. 
         [0014]    In accordance with yet another aspect, 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. 
         [0015]    In yet another aspect of the invention, the present invention is directed to a method of controlling the 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. 
         [0016]    Additional features and advantages of the invention will be set forth in the detailed description which follows and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein. 
         [0017]    It is to be understood that both the foregoing general description and the following detailed description are merely exemplary of the invention, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide further understanding of the invention, illustrate various embodiments of the invention, and together with the description serve to explain the principles and operation of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0018]      FIG. 1  is a top perspective view of a stove together with a fuel tank in accordance with an embodiment of the invention; 
           [0019]      FIG. 2  is a top 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 lines A-A; 
           [0026]      FIG. 4D  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 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. 
       
    
    
     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]    Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawing figures. 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 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 . Preheating pad  34 , is preferably made of a high temperature ceramic material and may be saturated with liquid fuel, alcohol or some other fuel source that can be ignited and burned to create sufficient heat over several minutes in order to cause at least partial vaporization of the fuel in the portion of cleaning valve assembly  28  and generator  27 , thereby allowing ignition of the fuel discharged through an exit orifice  36  of fuel tip  38  located at a top portion of the cleaning valve assembly  28  beneath burner  30  of burner assembly  22 . 
         [0032]    Turning now to  FIG. 3A , an exploded perspective view of stove  20  of the present invention is depicted. Burner assembly  22  including 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 . 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. 
         [0033]      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  FIG. 4A  through  FIG. 4E . As depicted in  FIG. 4A , cleaning valve assembly  28  preferably includes a valve housing  44  to which fuel tip  38  is attached. Positioned within orifice  36  of fuel tip  38  is a cleaning element, preferably a cleaning needle  46  ( FIG. 4C ). The needle  46  may be controlled by a control lever  48 , which extends from the valve housing  44  to and out a remote lever housing  50 . As shown in  FIG. 4B , lever  48  extends centrally through lever housing  50 . 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, limited flame and burner control can be achieved, and the stoves are not expected to have significant flame and heat adjustability. 
         [0035]    In accordance with a preferred embodiment of the present invention, fine-tuning flame adjustability is achieved with the use of a novel heat dissipating element, preferably a heat dissipating interface  52  positioned between the valve housing  44  and lever housing  50 . In a preferred embodiment, the heat dissipating interface 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 . 
         [0036]    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  that preferably measures between 0.02 (two-hundredths) and 0.005 (five-thousandths) of an inch in diameter, and most preferably 0.009 (nine-thousandths) of an inch in diameter. When lever  48  is rotated, bent end  54  of lever  48  takes an eccentric path that forms a cam in connection with the cleaning needle housing  56  that elevates and lowers cleaning needle  46  within the orifice  36  of fuel tip  38 . 
         [0037]    The movement 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 lever  48 . The inside of 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 orifice  36  as cleaning needle  46  moves up into 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 0.002 (two-thousandths) of an inch. 
         [0038]    The heat dissipating aspects of the present invention are preferably provided by heat dissipating interface  52 . More preferably, the entire length of lever  48  is also made from a low heat conducting material such as a ceramic material, titanium, stainless steel, or some combination thereof. The same is preferably also true for cleaning needle  46 . As a result of the heat from burner assembly  22 , the body of 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 the present invention, and in a preferred embodiment of the invention where lever  48 , cleaning needle  46  and heat dissipating interface  52  are all stainless steel and the length of heat dissipating interface  52  is approximately one and one-quarter inches long, lever housing  50  is approximately two-hundred (200) degrees F. and the end of the lever is approximately room temperature when the body of stove  20  is between five-hundred (500) and six-hundred (600) degrees F. and the stove is running. The longer the length of 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 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 that one and one-quarter (1¼) inches in length. The increased length itself assists with dissipation as does the additional surface area exposed to ambient air around that surface area. 
         [0039]    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. 
         [0040]    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. 
         [0041]    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 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. 
         [0042]    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.