Abstract:
A pellet stove is disclosed comprising a reverse flow heated air pathway defined by stove sections. In an illustrated embodiment, the space between upper and lower stove sections is open to provide a heating or oven area. The stove can be readily disassembled in part for easy portability.

Description:
TECHNICAL FIELD  
       [0001]    The technology disclosed herein relates to stoves that burn pellet fuel. 
       BACKGROUND  
       [0002]    Stoves that burn pellet fuel are known. These stoves typically burn a pelletized fuel which can be comprised of compressed wood products such as sawdust. Although variable, an example of pelletized fuel are pellets that are about one-quarter inch in diameter and from about one-half to one and one-half inches long. Thus, pellet stoves burn pellets of compressed combustible particulate materials with or without other ingredients. 
         [0003]    Some known pellet stoves use an auger or other powered feed mechanism for delivery of pellets to the stove for combustion. These delivery mechanisms can be complex and require a power source, which makes such stoves impractical for use in remote locations. 
         [0004]    Some other known pellet stoves can burn inefficiently. 
         [0005]    Therefore, a need exists for an improved pellet burning stove. 
       SUMMARY  
       [0006]    In accordance with one embodiment, a pelletized stove is disclosed which is compact and relatively light weight so as to be portable for use in remote locations, such as in a hunter&#39;s tent or an ice fish house. 
         [0007]    In accordance with an embodiment, a pellet stove can provide an air flow path from a combustion chamber that reverses direction as air travels along the flow path. A specific example is a generally J-shaped combustion chamber and flow path with one leg of the J being generally horizontal when the pellet stove is in use. 
         [0008]    In accordance with another aspect of an embodiment, pellets can be delivered to combustion chamber from a hopper by gravity. 
         [0009]    As yet another aspect of an embodiment, pellets reaching the combustion chamber portion of the stove can be guided, such as by a feed tube, onto an apertured grate with a flow of combustion air passing at least partially upwardly through the grate and pellets thereon to facilitate burning of the pellets. 
         [0010]    As a still further aspect of an embodiment, an ash receiving drawer can be positioned beneath the combustion chamber with the ash receiving drawer being partially opened to provide enhanced combustion air flow through the ash receiving drawer and to the underside of an apertured grate supporting pellets thereon. 
         [0011]    As yet another aspect of an embodiment, detachable legs can be used to support the pellet stove with the legs being adjustable in elevation to facilitate leveling of the stove. 
         [0012]    As a still further aspect of an embodiment, the combustion chamber and air flow path can be tubular comprising a first tubular section having a combustion chamber at one end portion thereof and having a longitudinal axis that is oriented approximately horizontally when the stove is leveled, a second upright tubular section and a third elongated tubular section having a longitudinal axis that also can be approximately horizontal when the stove is leveled for use. In an exemplary feature of a desirable embodiment, the first and third sections can be spaced apart by the second section and with the third section can at least partially, and desirably entirely, overlie the first section with a space provided therebetween. The space can be an open cooking zone which can function as an oven. 
         [0013]    In accordance with yet another more specific aspect of an embodiment, the sections can be of rectangular cross-section. 
         [0014]    As yet another aspect of an embodiment, upwardly projecting handles can be provided along respective sides of the first section with the handle portions being spaced apart, for example, by the first section. The handles can comprise elongated rails which provide a cookware supporting surface upon which cookware may be placed between the first and second sections to cook food therebetween. 
         [0015]    As yet another aspect of an embodiment, the first section can comprise an end with an end cap coupled thereto for movement between open and closed positions. When the end cap is open, access can be provided to a pellet supporting grate within the combustion chamber to permit removal and cleaning of the grate. 
         [0016]    These and other aspects and features of various embodiments are explained more fully in the disclosure below by way of examples. The invention is not limited to these specific examples but instead is defined by the claims set forth in this application. It should be noted that the invention is directed toward all novel and non-obvious aspects of a pellet stove in accordance with this disclosure, and methods of operating and assembling such a stove, both alone in various combinations and sub-combinations with one another. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0017]      FIG. 1  is a perspective view of one embodiment of a pellet stove shown supported by a plurality of legs. 
           [0018]      FIG. 2  is an exploded view of the stove of  FIG. 1  with selected detachable components of the stove shown detached from the assembled stove. 
           [0019]      FIG. 3  is a vertical sectional view through a portion of the pellet stove of  FIG. 1 . 
           [0020]      FIG. 4  is a side elevational view of the pellet stove of  FIG. 1 , with two of the legs removed for purposes of showing the rest of the stove more clearly. 
           [0021]      FIGS. 5A and 5B  illustrate an exemplary pellet fuel supply gate coupled to a hopper of a pellet stove for use in controlling the delivery of pellet fuel to the combustion chamber of the stove. 
           [0022]      FIG. 6  illustrates an exemplary hopper which can be used in the pellet stove of  FIG. 1 , together with an exemplary gate, such as shown in  FIGS. 5A and 5B , shown detached from the hopper. 
           [0023]      FIG. 7  is an exemplary ash receiving drawer which can be included in the pellet stove of  FIG. 1 . 
           [0024]      FIG. 8  is an exemplary pellet supporting grate having apertures therethrough for permitting the access of combustion air upwardly through the grate to pellet fuel supported thereon. 
       
    
    
     DETAILED DESCRIPTION  
       [0025]    With reference to  FIGS. 1-4 , an exemplary pellet stove in accordance with one embodiment of the disclosure comprises a stove body  10  comprising a first body section  12 , a second body section  14 , a third body section  16  and a vent coupling portion  18 . The first body section  12  can be elongated with a longitudinal axis and can comprise a first end portion  20  and a second end portion  22 . As can be best seen in  FIG. 3 , end portion  20  has an end  24  that can be selectively closed by an end cap  26 . End cap  26  can be shifted from a first closed position shown in  FIG. 3  to an open position (a partially open position being shown in  FIG. 2 ) so as to permit the removal of a fuel support such as an apertured pellet supporting grate  30  through the end  24  of the first section  12 . Access to the pellets for initially lighting the pellets can be achieved through the open end cap. In the embodiment shown in  FIG. 3 , end cap  26  is hinged along a lower edge thereof, such as indicated by hinge  40  to permit pivoting of the end cap in the directions indicated by arrow  42  between open and closed positions. A portion  50  of end portion  20  of the first section  12  can comprise a combustion chamber or combustion zone. The grate  30  supports pellets, some being indicated at  60  in  FIG. 3 , in a combustion zone of the combustion chamber  50  wherein the pellets can burn. 
         [0026]    The sections  12 ,  14 ,  16  and  18  comprise conduit sections in this example. The conduit section  12  defines an outlet  62  through which heated air such as indicated by arrows, some of which are numbered in  FIG. 3  with the number  70 , pass from the combustion chamber portion  50 . A combustion air flow passageway is provided to deliver combustion air to the combustion chamber. This combustion air is represented by arrows in  FIG. 3 , with some of the arrows being indicated by the number  74 . At least some of the combustion air, and desirably all of the combustion air, flows upwardly through the pellet supporting grate  30  and through pellets supported thereon. An elongated opening  80  is provided in section  12  below the grate  30  through which the combustion air can pass. An ash drawer receiving housing  82  can be coupled to the first section  12  for receiving an ash drawer  84  which can be slidable, such as indicated by arrows  86 , into the drawer receiving housing  82 . An ash drawer handle  88  can be used to facilitate movement of the ash receiving drawer into and out of the housing  82 . The ash receiving drawer can be open at the top so that ashes from consumed pellets can pass downwardly through apertures in the grate, one of such apertures being indicated by the number  90  in  FIG. 3 . 
         [0027]    The ash receiving drawer  84  can be shifted to partially open positions, such as to one such position shown in  FIG. 3 , to increase the combustion air flow (see arrow  96 ) into the ash receiving drawer and upwardly through the apertures  90 . In a typical example, although variable, the drawer is open approximately one and one-half inches to provide a draft for the burning fuel. The ash drawer  84  in the illustrated embodiment can be entirely removed to facilitate dumping of the ash. 
         [0028]    The grate  30  in one exemplary form is shown more clearly in  FIGS. 2 and 8 . The illustrated grate comprises a base, such as a plate-like body portion  120  having the apertures  90  therethrough. Exemplary apertures are approximately one-half inch in diameter, although this size can be varied. Any durable material can be used for the grate with one-eighth inch stainless steel being a specific exemplary material. The illustrated grate also comprises an upwardly angled stop portion  130  having a downturned lip or handle  132  at a distal end thereof spaced from the location where the plate  130  is coupled to plate  120 . A rear portion  134  of the plate  120  is positioned generally beneath the upright portion  130  with the upright portion extending at an acute angle B relative to the base in this example. 
         [0029]    With reference to  FIG. 1 , the illustrated first housing section  12  comprises an upper surface  136 , a lower surface  138 , and first and second side surfaces  140 , 142  (it being understood that these side surfaces would be curved if section  12  were, for example, of right cylindrical construction). With this construction, referring again to  FIG. 3 , the opening  80  can be an elongated opening, that is elongated in the lengthwise direction, and, for example, can be rectangular with the opening  80  extending through the lower surface  138 . 
         [0030]    The illustrated exemplary embodiment of FIGS. I and  2  comprises an upwardly extending hopper-neck receiving sleeve  160  that can, for example, be of a right cylindrical construction. A pellet fuel inlet opening  162 , which can be of circular cross-section, is provided through upper surface  136  at the base of the sleeve  160  through which pellets can be delivered to the combustion chamber  50 . A pellet guiding or feed tube  170  can have an open upper end portion  174  communicating with the opening  162  through which pellet fuel can be delivered. The tube  170  can also comprise a lower end portion  176  with an outlet opening  176  through which pellets can pass onto the grate  34 . The tube  170  can be angled away from end  24  and toward the combustion chamber zone  50 . Although variable, this angle can also be at the angle B. An exemplary angle β is 45°, although variable. The angled feed tube assists in moving pellets away from the hopper opening toward the combustion zone. In this case, as can be seen in  FIG. 3 , the grate  30  can be inserted into the end section  20  through end  24  until plate  130  engages the outer surface of feed tube  170 , thereby limiting the depth of insertion of the grate  30 . Thus, plate  130  and feed tube cooperate to stop the insertion of the grate at the appropriate location. Other forms of stops can be used if desired. 
         [0031]    A hopper  200  is shown ( FIGS. 1 and 3 ) for receiving pellets  60  therein. The illustrated hopper comprises a neck portion  202  which also can be cylindrical in cross-section or otherwise shaped to mate with sleeve  160 . The hopper thus can be loosely positioned within sleeve  160 , although set screws and other types of fasteners could be used if desired. Disassembly of the hopper from the remaining portions of the stove is facilitated by such a loose connection. The hopper comprises side walls  204  which can be angled, such as at the angle a from horizontal as shown in  FIG. 3 . Although variable, a specific example of a is  62  degrees. The hopper can be of other sizes and shapes. When a gate  230  (explained in greater detail below) is operated to open the base of the hopper, pellets travel under the influence of gravity, in the direction indicated for example by arrows  240 , downwardly through the hopper neck  202 , the sleeve  160 , the pellet fuel inlet opening  162 , the feed tube  170 , and through the end  176  of the feed tube  170  to the combustion zone  50  and on to the grate  30 . The distance between the bottom edge of the feed tube  170  and the upper surface of the grate  130  can be varied by varying the length of the feed tube and/or the size of the combustion chamber to assist in controlling the size of the pellet pile in the combustion zone. In general, the more pellets and larger the pile permitted in the combustion zone, the hotter the resulting fire. Exemplary distances between the bottom edge of the tube and the grate are from about one-half inch to one and one-half inches with one inch being a specific example for a stove having a first section made out of six inch square steel tubing. Another specific example would be one-half inch spacing for a stove having a first section of 6 inch wide by 3 inch high rectangular steel tubing. 
         [0032]    As can be seen in  FIG. 1 , a plurality of legs  280 , such as two front legs and two rear legs, can be used to support the stove. Since these legs can be identical and can be identically coupled to the stove, such as to the first section  12  and more specifically to side walls thereof in one example, only one of such legs  280  and associated coupling components will be described in detail. In particular, leg  280  can be of a tubular construction, such as of a square cross-section. The leg can comprise a lower end portion  282  and an upper end portion  284 . The leg can be bent, for example, at  288  ( FIG. 1 ) so that a lower portion of the leg  290  flares outwardly while an upper portion of the leg  292  can be oriented in an upright, for example vertical, orientation when the stove is assembled. A sleeve  300  can be coupled to the first stove section  12 , such as by welding or otherwise securing the sleeve  300  to wall  140  thereof. In this disclosure, the term “coupled to” includes both direct connection of two components together and indirect connection of two components through one or more other components. The sleeve can be closed at its upper end and open at its lower end so as to slidably receive the end portion  292  of leg  280  therein. By sliding leg end portion  292  into and out of the sleeve, the elevation of the stove can be adjusted. A level holding mechanism, such as a set screw  302 , threadedly received by sleeve  300  and engageable with leg section  292 , can be provided to hold the leg at its desired elevational adjustment. 
         [0033]    As also can be seen in  FIGS. 1 and 4 , the illustrated stove can comprise handles to facilitate lifting of the stove. An exemplary stove without the hopper weighs under  100  pounds. For example, for a stove comprising a first section  12  of 6 inches wide by 6 inches high by 39 inches long by 3/16 inch thick steel; a second section  14  of 6 inches wide by four inches deep by 11 inches long (at longest point) by ⅛ inch thick steel; a third section of 6 inches wide by four inches deep by 24 inches long (at longest point) by ⅛″ thick steel, with coupler section  18 , the hopper sleeve  160 , feed tube  170 , grate  30 , end cap  26 , ash drawer housing  82 , ash drawer  84 , and legs  280  and without the hopper  200  weighs about 96 pounds, making the stove readily portable. Of course, the stove can be made to any size larger or smaller than the specific dimensions described above. 
         [0034]    In a specifically illustrated example, the handles comprise respective first and second handles with elongated rails  340 , 342  being exemplary handles. These rails  340 , 342  are supported by respective upright supports  344 , 346 , 348  and  350  for rail  340  and  352 , 354 , 356  and  358  for rail  342 . The rails shown in this example extend upwardly above the upper surface  136  of first section  12 . As can be seen in  FIG. 4 , cookware, such as a baking pan or fry pan  360 , can be supported by the rails above the surface  136  and in the space between sections  12  and  16 . This space can be, for example, about 8 inches between surface  136  of section  12  and the lower surface of section  16 . This space can be at least partially open (unobstructed), door-free, and desirably is entirely unobstructed except by the handles, and can be entirely unobstructed at one side thereof except by the handles. The space can be open substantially as shown and in effect can be used as an oven. The temperature in this space can be varied and can, for example, be 450° F. between tube sections  12  and  16  in this heating zone. In addition, in the example wherein rails  340 , 342  extend upwardly above the surface  136 , when the legs are detached from the stove, the legs can be placed and stored on upper surface  136  with the rails  340 , 342  holding the legs in place, making them easier to transport with the stove. 
         [0035]    Referring again to  FIG. 3 , the illustrated stove or body section  14  comprises a lower portion  400  having an inlet communicating with the outlet  62  of first section  12 . Section  14  also comprises an upper end portion  402  having an outlet communicating with an inlet at a first end portion  404  of the section  16 . The opposite end portion  406  of housing section  16  comprises an outlet  408  communicating with an inlet of a vent coupler portion  410  having an outlet  412 . A vent, such as a stove pipe,  414  can be coupled to vent coupler  410  for exhausting the stove as desired. For example, stove pipe  414  can communicate through the roof or side wall of a hunter&#39;s tent. Thus, as can be seen from  FIG. 3 , combustion air  96  entering the ash drawer  84  flows upwardly through the grate  30 , as indicated by arrows  74 , and is heated in the combustion chamber zone  50 . The heated air  70  travels along the length of the first section  12 , upwardly into the second section  14 , and through the third section  16  in a direction reversed from the flow direction through the section  12 . The heated air exits through the coupler  18 . 
         [0036]    As can be seen from  FIGS. 2 ,  4 ,  5 A,  5 B and  6 , the hopper neck portion  202  can be provided with a gate receiving slit  480  extending, for example, halfway into the neck  202 . A commercially available manually actuated gate  230  can be used to control the flow of pellet fuel from the hopper and into the combustion chamber of the stove. The gate  230  can comprise a sliding member  482  movable in a direction of arrow  44  in  FIG. 5B  to open the gate and in a direction of arrow  486  in  FIG. 5  to close the gate. An end portion  487  of the slide member  482  can have a configuration shaped to close the neck  202  when the gate is in a closed position. For example, end portion  487  can have a semi-circular peripheral edge portion  488  which bears against the interior surface of the unslit portion of a circularly configured neck  202 . A locking mechanism, such as a set screw  490 , can be used to selectively lock the gate in the position to which it has been moved. 
         [0037]    In some embodiments of the pellet stove, the stove burns for about eight hours with one 40-lbs. bag of pellets as fuel, i.e., at an approximate average burn rate of about 5 lbs. per hour. In another embodiment of a smaller-sized pellet stove, the burn rate may approach approximately 2.5 lbs. per hour. 
         [0038]    Various components of the stove may be finished with baked on stove paint. The grates may be constructed of stainless steel. 
         [0039]    Having illustrated and described the principles of our invention with reference to a illustrated embodiments, it should be apparent to those of ordinary skill in the art that these embodiments may be varied in arrangement and detail without departing from the inventive principles set forth herein. We claim all such variations which fall within the scope of the following claims.