Abstract:
A log stove and fire stand are disclosed wherein the fire stand has a grill with three adjustable legs positioned over the log stove to complement the structural integrity of the burning log stove. The log stove may include a variable cross-section static air flow design and a ventilator gate that provide a method to inject excessive air (oxygen) flow into the combustion chamber throughout the burn cycle for complete fuel consumption. An excessive air volume to fuel ratio insures complete combustion of the billet thus reducing pollution.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a stove for heating and/or cooking. In particular, the present invention relates to a stove formed from a single log billet. 
       BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to cooking and/or warming. The invention can be used for any outdoor activities, in an emergency when the power grid goes down or other natural or manmade disasters. The invention is easily stored with an exceptional long shelf life. 
         [0003]    The burning of an individual stump or billet as a stove is known in the art. In such prior stoves, the stove is created by using a saw to make multiple, constant width slots that extend across a diameter of and longitudinally into one end of the log billet. The intersection of these slots creates a combustion chamber where combustion of the log primarily takes place. Intake and exhaust of air occurs through the end of the billet or through the slots created in the side of the billet. 
         [0004]    Existing log stoves exhibit poor burning characteristics. The uncontrolled burning creates a large amount of smoke, soot, and airborne particulates. Temperature control is non-existent during the entire burn cycle. The log may be unstable and unable to support a cooking utensil during approximately ¾th of the burn cycle. Existing stoves may become a hazard to persons or property when the stump burns down past the ¾th height and collapses. 
         [0005]    In addition, ignition of existing log stoves is made by stuffing grass, leaves or other solid flammable material into the combustion chamber and setting it on fire, creating copious amount of smoke. 
         [0006]    The present invention addresses these and other deficiencies in existing stoves by providing various advantages, including an ability to control airflow into the combustion chamber. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0007]    Advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings. 
           [0008]      FIG. 1  is a top view showing a fire stand and log billet in accordance with embodiments of the present invention. 
           [0009]      FIG. 2  is a front view of the embodiment of  FIG. 1 . 
           [0010]      FIG. 3  is a side view of a log billet in accordance with embodiments of the present invention. 
           [0011]      FIG. 4  is a top view of the embodiment of  FIG. 3 . 
           [0012]      FIG. 5  is a cross-section view of the embodiment of  FIG. 3 . 
           [0013]      FIG. 5A  is a cross-section view of an alternative embodiment of the ventilator gate. 
           [0014]      FIG. 6  a perspective view of the log billet in accordance with further embodiments of the invention. 
           [0015]      FIG. 7  shows the configuration of the slots cut into the log billet in accordance with an embodiment of the invention. 
           [0016]      FIG. 8  shows a top view of a fire stand in accordance with embodiments of the invention. 
           [0017]      FIG. 9  is a side view of the embodiment of  FIG. 8 . 
           [0018]      FIG. 10  is a partially cut-away side view of a leg of the fire stand illustrated in  FIG. 8 . 
           [0019]      FIGS. 11-12  are cross-sectional views of an embodiment of the leg shown in  FIG. 10 . 
           [0020]      FIG. 13  shows a combustion diagram. 
           [0021]      FIG. 14  shows a side view of a fire stand in accordance with embodiments of the invention. 
           [0022]      FIG. 15  shows a top view of a base assembly of the fire stand of  FIG. 14 . 
           [0023]      FIG. 16  shows a cross sectional view of a support tube and base tube of the fire stand of  FIG. 14 . 
           [0024]      FIG. 17  shows a top view of a grill assembly of the fire stand of  FIG. 14 . 
           [0025]      FIG. 18  shows a side view of a diffuser for use with embodiments of the grill assembly. 
           [0026]      FIG. 19  is a perspective view a grill lock for use with embodiments of the grill assembly. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Throughout this application, the directional references, such as forward, rearward, left, right, bottom and top, will be used. These and other such references are relative to the firing direction of the firearm, which fires in a forward direction. Such references are used for ease in describing the present invention and should not be construed as limiting the scope of the invention. As used in the description herein and throughout the claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise: the meaning of “a,” “an,” and “the” includes plural reference, the meaning of “in” includes “in” and “on.” Also, reference designators shown herein in parenthesis indicate components shown in a figure other than the one being discussed. 
         [0028]    The present invention addresses deficiencies in existing log stoves with, among other advantages, consistent temperature control by controlling the burn rate, which is a function of controlling air flow (oxygen) into the combustion chamber. The airflow (oxygen) is introduced into the combustion chamber through a varied volume structure. 
         [0029]    A ventilator gate may also be incorporated at the mouth of a ventilator port to throttle airflow into the base of the combustion chamber. The initial ignition requires the greatest amount of air (oxygen) to initiate the burn cycle. After the ignition has started, the ventilator gate can be adjusted to give required maximum temperature. A mixture of alcohol or other flammable liquid may be mixed with a scented material and squirted or otherwise introduced into the combustion chamber and the ventilator port. This mixture, when ignited will initiate combustion. The scented material may be citronella, which provides an additional advantage of generating scent vapors that may serve to disperse mosquitoes and other insects. 
         [0030]    This throttle mechanism, as described more fully below, may be made of combustible material that is consumed in the last stage of the burn cycle. Leaving ash as the only residue remaining after the burn cycle. 
         [0031]    A fire stand may also be included as an integral reusable component of a log stove system in accordance with the present invention. The fire stand may fit over the log stove and hold cooking or other heated utensils directly over the log stove active flame front. The fire stand may support the weight of a pan or other utensil above the top surface of the log stove, thus preventing a premature collapse of the cooking surface. The fire stand may have a circular grill with three foldable legs that extend out to support the circular grill above the fire front. These legs may be adjustable and can be adjusted to various heights. In some embodiments, the legs may be adjusted from a height of one inch or more above the flame front to a height of approximately three inches above the fire spent log during the last stages of the burn cycle. 
         [0032]    As illustrated in  FIGS. 1 and 2 , a fire stand  1  straddles the log billet  2  of a log stove. The stand may function to support a load, such as a cooking utensil, set in position over the log stove flame. The fire stand  1  may also prevent the collapse of the log billet  2  as it is consumed. 
         [0033]    Referring to  FIGS. 1-2 and 9-12 , embodiments of the fire stand  1  comprise a wire formed circular grill  3 . The grill may include multiple decreasing diameter metal rings welded in a balanced concentric pattern to form the grill  3 . The grill  3  extends over at least a portion of the top surface of the log billet  2 . Embodiments of the grill include female brackets  4  that extend from a lateral edge or underside of the grill  3 . 
         [0034]    Multiple legs  6  extend from adjacent an edge of the grill. The illustrative embodiments show three legs, but more or fewer may be used. The legs  6  may be collapsible. Male hinge plates or brackets  6 A are attached to an upper end of the each leg. The hinge plates  6 A may be connected to the female brackets  4  by roll pins  7 , such that the legs  6  pivot relative to the grill  3 . 
         [0035]    Referring to  FIGS. 8-12 , embodiments of the fire stand may be set up initially by unfolding the three collapsible legs  6  and expanding the legs outward until the legs contact the grill leg stops  16  at approximately 20 degrees angle. The leg lock rings  17  are pushed to the unlock position. The extension leg interior tube  19  will be pulled out of the outer tube  20  to the full extend position and the lock rings  17  pulled outward setting the lock ring in the locking grooves  18 . A collapsible leg assembly  6  with the captured multi-position (neutral/lock position) lock ring  17  of embodiments of the invention provides a novel push-pull lock mechanism that can be manipulated when hot by taping the lock ring with any appropriate instrument. 
         [0036]    Referring to  FIGS. 1-2 , the assembled fire stand  1  be centered and positioned over the log stove combustion chamber exhaust port  14 . The fire stand  1  will be leveled using the three extended legs. A flammable ignition mixture may be squirted in to the combustion chamber  9  and a ventilator port  11 . This flammable mixture may be ignited with any open flame device. Alternatively, other methods of igniting the log billet may be used as would be understood by one of ordinary skill in the art. Burn temperatures can be adjusted by either opening or closing the ventilator gate  12  to achieve the desired temperature. 
         [0037]    The fire stand height can be adjusted to maintain a preferable distant from the burning log flame front by reducing the three legs  6  height by reversing the set up procedure. Referring to  FIGS. 10-12 , an internal groove or swage slot  21  is provided internally in the outer tube  8  to allow an internal guide pin  9 , riding in the slot  21 , which prevents the extension tube  19  from falling out of the outer tube  8 . 
         [0038]    Referring to  FIGS. 3-7 , the log stove comprises a log billet  2 . Appropriate billets may have a variety of diameters. Preferably, the log billet has a minimum of six inches outside diameter, but smaller sizes are possible. The maximum diameter may be fifteen inches or more. The log billet  2  can be any combustible wood, including evergreen or deciduous. Appropriate billets may have a variety of lengths. In preferred embodiments, the billet is at least six inches in length and may extend to thirty-six inches or more. 
         [0039]    The log stove billet  2  has a combustion chamber  9 . The combustion chamber may be generally cylindrical and bored into the billet from a top surface. Preferably the combustion chamber has a diameter of at least one inch but not greater than six inches. The combustion chamber may be machined to a depth of one inch above the base  10  of the billet  2   
         [0040]    A ventilator port  11  may be machine or otherwise cut in the billet to intersect the chamber  9  at or near the bottom of the combustion chamber bore hole. In preferred embodiments, the ventilator port  11  may have a diameter from one inch to three or more inches. 
         [0041]    Alternatively, the ventilator port  11  may be machine with a tapered hole to form a venturi structure  22  as illustrated in  FIG. 5A . The venture  22  tapers from a larger diameter into a smaller diameter to accelerate airflow velocity into the combustion chamber  9 . The increased airflow will accelerate the ignition sequence within the combustion chamber  9 . 
         [0042]    The ventilator port may be formed at an angle to the combustion chamber. For example, illustrative embodiments show the ventilator port being formed perpendicular to the longitudinal axis of the combustion chamber and log billet. However, other angles may be used. 
         [0043]    Embodiments of the ventilator port  11  comprise an adjustable gate  12  attached to an outer surface of the billet. The gate  12  may be attached with pin  13  formed from flammable or combustible material. The pin  13  attachment allows the gate  12  to swing over the ventilator port  11  in an adjustable manner to throttle airflow in to the combustion chamber  9 . The adjustable ventilator gate  12  can be rotated across the mouth of the ventilator port to control air flow volume, thus reducing burn rate and temperature which will modulate burn time of the log stove. The adjustable ventilator gate  12  and attaching pins  13  may be constructed of material that will be consumed as the log billet  2  burns. 
         [0044]    Embodiments of the log stove comprise intersecting, graduating slots  15  formed between the combustion chamber and an outside surface of the billet. In the illustrative embodiments, the slots are formed by two intersecting slots cut into the top surface of the billet. The slots preferably intersect at 90 degrees. However, other intersection angles may be used and more or fewer slots may be used. The slots are referred to herein as vari-vents. The slots may be formed by progressively narrower stepped cuts into the log billet from the top surface. 
         [0045]      FIG. 13  shows an illustrative combustion diagram. Combustion is a chemical reaction of rapid oxidation started by the correct mixture of fuel, oxygen and an ignition source. The operating range and efficiency of a log stove may be established at an improved setting by maintaining controlled excess airflow. The airflow may be obtained by the use of a self-adjusting airflow to compensate with the biomass (wood) lost due to the burn rate. 
         [0046]    The vari-vent described herein provides for an improved airflow. In one illustrative embodiment, the vari-vent consists of four slots cut on a quadrant layout extending into the combustion chamber  9 , which is a vertical chamber, varying in diameter of one to two and one half inches and bored to a depth of approximately eleven inches. Each slot will have a top cavity  15 A approximately one inch wide with the depth varying from one half inch to four inches, depending on log billet diameter. Extending down from the bottom of the one inch slot, a cut  15 B varying in width between three eighths to one half inch will extend down the billet approximately four to seven inches. An advantage of this embodiment is that the flow of oxygen balances with the available remaining log mass as it burns. 
         [0047]    The larger volume in the upper part of the vari-vent  15 A cut out of this embodiment produces maximum airflow needed to produce ignition and fast prorogation of the flame front. The reduced volume in the lower section of the vari-vent  15 B cut out will adjust the air flow as the burning expands the combustion chamber which maintains higher air flow that balances air flow (oxygen) to fuel ratios. 
         [0048]      FIGS. 14-19  illustrate further embodiments of a fire stand. The fire stand may comprise a base assembly  30 . Embodiments of the base assembly may include a base tube  32 . The tube may extend around all or a portion of the base periphery. For example, as shown in  FIG. 15 , the base tube  32  extends around three sides of a generally square base. In other embodiments, the base may be round, triangular or some other shape. 
         [0049]    The base assembly  30  may further comprise a base plate  34 . The base plate may be welded to the base tube  32  or otherwise attached to fill an area within a periphery created by the base tube. The base plate  34  may include holes  58  or may be formed of expanded steel, mesh or other similar materials. Alternatively, the base plate may be steel or aluminum plate, including diamond plate. The base plate may serve a spark arresting function as well as providing a base for supporting the billet  2 . The base assembly  30  may further comprise a base skirt  36  extending upwardly from the base plate  34 . The base skirt may surround a lower portion of the billet  2  and may for a generally cylindrical cavity. The base skirt  36  may serve to contain and stabilize the billet as well as containing ashes generated as the billet burns. 
         [0050]    A support tube  38  may extend upwardly from a portion of the base tube  32 . A weld  40  may connect the support tube to the base tube. The support tube may comprise upper and lower parts connected by a slip joint  42  that comprises a tube having a larger diameter than the support tube. The slip joint may be positioned over a lower portion  38 A of the support tube and attached thereto. An upper portion of the support tube  38 B may then be removably inserted into the slip joint. 
         [0051]    The support tube may provide support for a grill assembly. The grill assembly may comprise a grill skirt  46 . The grill skirt may comprise a generally cylindrical side wall that may surround an upper end of billet  2 . A grill plate  48  may be positioned to cover the top end of the grill skirt  46 . The grill plate may include holes  60  or may be formed of expanded steel, mesh or other similar materials. Alternatively, the base plate may be steel or aluminum plate, including diamond plate. The grill plate  48  may be attached to the grill skirt  46  by a weld  50  or by other means including, but not limited to adhesive, fasteners or other means. Alternatively, the grill plate and grill skirt may be integrally formed. The grill plate  48  may further comprise a diffuser  52  positioned generally in the center of the grill plate so that the diffuser is positioned above the combustion chamber exhaust port  14 . The diffuser may serve to deflect the exhaust gasses or to diffuse the heat generated by burning the billet across a larger area of the grill plate  48 . 
         [0052]    The grill assembly may be attached to the support tube  38  by a grill lock  44 . The grill lock  44  may comprise a tube that fits over the support tube for slidable movement relative to the support tube. An extension arm  54  may connect the grill skirt  46  to the grill lock  44 . The grill skirt, extension arm and grill lock may be connected by welds, fasteners or other attachment means. The grill lock may further comprise a locking mechanism  56 . In the illustrated embodiments, the locking mechanism  56  is shown as a bolt that is inserted through a threaded hole in the grill lock  44  so that an end of the bolt can be tightened against an outside surface of the support tube. In this manner, the grill assembly can be positioned vertically and locked into place. In certain embodiments, the grill assembly is locked into place at a vertical distance from the base assembly such that the grill plate  48  is suspended some distance above a top surface of the billet  2  and the grill skirt  46  at least partially surrounds an upper end of the billet  2 .