Abstract:
A wood or other bio mass fueled appliance is disclosed for maximum efficiency and low cost construction for home, garage, workshop, and barn. Comprised of a vertical cylindrical outside shell ( 12 ) outside bottom ( 16 ) and outside top ( 14 ) enclosing an inside shell ( 24 ) inside bottom ( 28 ) and inside top ( 26 ). Inside shell ( 24 ) forming a vertical cylindrical chamber ( 36 ) accessed by load door ( 38 ) and ash door ( 40 ), through which disassembled baffles ( 32 ) may pass. A suitable means for igniting fuel in chamber ( 36 ) and controlling burn rate by draft regulators ( 42 ) and fan limit switches ( 52 ). Whereby circular baffles ( 32 ) elevated by 90° angle shaped supports ( 30 ) suppress the flow of flame and exhaust gases from entering flue ( 22 ). Exhaust gases and flame pass by gap ( 50 ), directing energy toward the inside surface of inside shell ( 24 ) inside bottom ( 28 ) and inside top ( 26 ). Thus maximizing the efficiency of heat transferred from chamber ( 36 ) to the air or fluid in space ( 18 ) circulated through ducts ( 20 ) by blowers/pumps ( 48 ) and directed by air deflectors ( 46 ) producing economizing results.

Description:
This application claims priority to U.S. Provisional Application No. 61/268,232, filed Jun. 10, 2009, which is hereby incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     This application relates generally to an appliance for burning solid fuels, such as wood, corn, pellets, etc., and more specifically for better combustion, more efficient heat distribution, and more economical construction. 
     With the increased price of energy, especially the fossil fuels, interest in alternative energy sources, mainly wood derived, to heat the interior space of any structure needing a rise in temperature has grown significantly over the past years, largely by moderate income families trying to reduce the bite of inflation, but also by a sizable segment of low income families who simply cannot afford fossil derived fuels. 
     Wood-burning devices have been well known for a long time, however, their popularity fluctuates. When petroleum fuel is readily available and reasonably priced, wood burning devices use declines. Recently we have seen a resurgence of interest in the use of wood and other bio-mass fuels as a heating fuel. Many of the reasons for the increase include rising petroleum fuel costs, the availability of wood and alternative fuels, and the staggering effects mining, drilling, processing, transporting and the burning of fossil fuels have on the environment. A problem with existing wood-based and other solid fuel burning appliances, however, is their lack of efficiency. That is, they are inefficient in many ways. First, known wood burning appliances must generate more heat than comparable petroleum fired furnaces, in order to adequately warm remote parts of the space in which it is situated. Moreover, existing wood-based and other solid fuel devices generally tend not to burn their fuel as completely as petroleum fueled furnaces and a significant amount of heat escapes directly out the flue. The, e.g., rectangular or square, shape of known appliances also have many design flaws. As a result, the cost advantages of burning wood or solid fuel over petroleum based fuels are diminished. 
     The resurgence of the interest in burning wood over fossil fuels may also be attributed to the many benefits of burning of wood over fossil fuels. One of the largest benefits of burning wood over fossil fuels is that a person can harvest, process and store wood with minimal harmful affects to the environment. For example, if a pile of wood is spilled, there is no harm to the environment. In contrast, if petroleum fuel is spilled, there is a very large pollution control cost associated therewith. The storing of fossil fuels also requires special containers, whereas wood fuel can simply be piled on the ground or placed inside a structure where it is going to be used. In addition, wood supply is easily accessed by most individuals who are independent and interested in not being dependent on large petroleum corporations who often fluctuate price for the benefit of the corporation and not the individual consumer. 
     There are many ways in which wood fired and petroleum fired furnaces are not directly comparable. For instance, a pound of wood is not directly comparable to a pound of oil. Oil will flow into a furnace while wood has to be physically loaded after the fire cools down. In this example labor required to deliver the fuel for combustion is not directly comparable from one type of furnace to the other. 
     There are many ways in which wood fired and petroleum fired furnaces are comparable. Since wood is a simple compound, made up of less elements, less waste is generated. Unburned oil puts hydrocarbons into the air and wood does not. Hydrocarbons from fossil fuels are suggested to be the cause of global warming and not the burning of wood. Trees grow by taking all that is needed out of the air and soil to grow. Thus, when burned, other growing trees will absorb what was put into the air. Oil is nonrenewable. 
     In comparing wood furnaces with one another. The current obstacle with wood is efficiently burning the wood and distributing the wood&#39;s heat in a structure. A problem with existing wood furnaces is their lack of efficiency. Rectangular wood stoves need more fuel to overcome the flaw of their shape. Because square or rectangle wood furnaces have cold spots and hot spots they tend to be operated very hot when re-fueled and a comfortable temperature is trying to be reached. They are inefficient in two other ways. A wood furnace must generate more heat, than petroleum fired furnaces, in order to adequately warm remote parts of the space in which it is situated. Existing wood burning devices generally do not burn their fuel as completely as petroleum fueled furnaces. A significant amount of heat escapes directly out the flue. Rectangular in nature wood burning furnaces have hot spots in the back primarily due to the existence of their corners. As a result, the cost advantages of burning wood or solid fuel over petroleum based fuels are diminished. 
     From the above, it can be seen what is a need for a device that is easy-to-use, more economical to produce, and efficient to use. 
     SUMMARY OF THE INVENTION 
     The present invention is a device for burning wood or other solid fuels with more efficient heat distribution and a more economical construction. 
     There are many objects of the present invention in its various embodiments that may be addressed individually or in combinations and permutations. Each embodiment may address one or several of the following objectives. 
     An object of this invention in one embodiment or variant of the invention is to provide an appliance for efficiently distributing heat from wood-based fuel or other solid fuel. 
     Another object of this invention in one embodiment or variant of the invention is to provide a device for a more economical construction. 
     Another object of this invention in one embodiment or variant of the invention is to provide a device that limits or eliminate smoke that comes out the loading door due to the position of the baffle. 
     Another object of this invention in one embodiment or variant of the invention is to provide a device without a hot spot in the back due to the shape, position, and use of baffles. 
     Another object of this invention in one embodiment or variant of the invention is to provide a device without hot or cold spots. 
     Another object of this invention in one embodiment or variant of the invention is to provide a device with more longevity from operational burnout deterioration. 
     Another object of this invention in one embodiment or variant of the invention is to provide a device with heat baffles that can be serviced through the appliance&#39;s load door. 
     Another object of this invention in one embodiment or variant of the invention is to provide a device with self centering heat baffles. 
     Another object of this invention in one embodiment or variant of the invention is to provide a device that ensures against eventual operational warping of the fire chamber. 
     Another object of this invention in one embodiment or variant of the invention is to provide an appliance that can have a three piece fire grate that has a two piece constructed exterior circumference design with a ship lap construction that would accept a circular center piece that was constructed with a ship lap exterior edge, to allow once all assembled a twisting or shaking action of the center grate that will travel by the support of the outside grates. 
     Another object of this invention in one embodiment or variant is to provide an appliance that can have a friction/compression closure system for the sealing of the load door and ash door. The closure system will be comprised of a lever that rotates on a axis with a tensioning devise (possibly springs) on each side to provide compression and a door that has a surface that the latch will mate with and that surface can have a raised angled step to help with said compression. 
     Another object of this invention in one embodiment or variant is to provide an appliance that can have a two speed blower that can switch from low speed to high speed or from high speed to low speed automatically. 
     Another object of this invention in one embodiment or variant is to provide an appliance that can have an outside shell that encases the entire inside shell except the loading door area, ash door area and flue exhaust pipe. 
     Another object of this invention in one embodiment or variant is to provide an appliance that can use different fuels in the fire box such as solid firewood, wood pellets, wood chips, manufactured or pressed logs, corn, corn cobs or any other solid fuel. 
     Another object of this invention in one embodiment or variant is to provide an appliance that can have a different fuel delivery system such as feed door for hand placement of firewood, feed augur for corn or wood pellet, conveyor, or other means. 
     Another object of this invention in one embodiment or variant is to provide an appliance that can have different systems of evacuating convection heat off from the fire box, such as air forced by a blower or fan through space between the fire box and outer shell or use of a liquid pumped or not pumped between the fire box and outer shell. 
     Another object of this invention in one embodiment or variant is to provide an appliance that can have an air wash system for the cleaning of glass in the load door. 
     These and other objects and advantages of the invention will be clear in view of the following description of the invention including the associated drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described hereafter in detail with particular reference to the drawings. Throughout this description, like elements, in whatever embodiment described, refer to common elements wherever referred to and referenced by the same reference number. The characteristics, attributes, functions, interrelations ascribed to a particular element in one location apply to that element when referred to by the same reference number in another location unless specifically stated otherwise. All Figures are drawn for ease of explanation of the basic teachings of the present invention only; the extensions of the figures with respect to number, position, relationship, and dimensions of the parts to form the preferred embodiment will be explained or will be within the skill of the art after the following description has been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength and similar requirements will likewise be within the skill of the art after the following description has been read and understood. 
         FIG. 1  is a perspective view of an appliance for burning solid fuels. 
         FIG. 2  is a center section view taken from  FIG. 1 . 
         FIG. 3  is a section view taken from  FIG. 2 . 
         FIG. 4  is another section view taken from  FIG. 2 . 
         FIG. 5  is a perspective partial cut away view of the solid fuel burning appliance in use. 
         FIG. 6  is a top view of a fire grate for the solid fuel burning appliance. 
     
    
    
     DRAWINGS REFERENCE NUMERALS 
     
         
         
           
               12  outside shell 
               14  outside top 
               16  outside bottom 
               18  space 
               20  duct 
               22  flue 
               24  inside shell 
               26  inside top 
               28  inside bottom 
               30  baffle support 
               32  baffle 
               34  notch 
               36  chamber 
               38  load door 
               40  ash door 
               42  draft regulator 
               44  support 
               46  deflector 
               48  blower/pump 
               50  gap 
               52  switch 
               54  fire grate 
               56  first grate section 
               58  second fire grate section 
               60  center fire grate 
               62  window 
               64  air wash system 
           
         
       
    
     DETAILED DESCRIPTION 
     Preferred embodiments of the invention will now be described, by way of example only and not to limit the invention, with reference to the accompanying drawings. 
       FIG. 1  is a perspective view of an appliance for burning solid fuels according to at least one embodiment of the appliances disclosed herein. The appliance, e.g., a furnace, boiler, etc., is comprised of an outer shell  12 , an outside bottom  16  and outside top  14 . The outer shell  12  is a vertical cylinder in the preferred embodiment. General construction of the appliance is from A36 mild sheet steel or any other material suitable for this means. The material may be joined by welding or by any other method suitable for joining the construction material. Protruding from the outside top  14  of the appliance is a flue  22  and one or more ducts  20 . Protruding from the back of the outside shell  12  is a housing containing one or more blowers/pump  48 , controlled by one or more fan limit switches  52 . Protruding from the front of the outside shell  12  is a load door  38  and ash door  40 . Load door  38  may or may not contain one or more draft regulator&#39;s  42 . In the preferred embodiment load door  38  contains two draft regulator&#39;s  42  and may contain a glass window  62  to view combustion. The glass window  62  may be serviced by an air wash system  64  for keeping the glass clean. By means of redirecting airflow from one or more draft regulators  42 . Ash door  40  may or may not contain one or more draft regulator&#39;s  42 . In the preferred embodiment, ash door  40  contains one draft regulator  42 . 
     Load door  38  can have a friction/compression closure system for the sealing of the load door and ash door. The closure system may be comprised of a lever that rotates on an axis with a tensioning device, such as a cam or springs, on one or each side to provide compression and a door that has a surface that the latch will mate with and that surface can have a raised angled step to help with said compression. An automatic auger or other delivery system may be installed in conjunction with load door  38  to deliver any kind of solid fuel into chamber  36 . 
       FIG. 2  is a center section view taken from  FIG. 1 . Disclosed in this view is an inside shell  24  with an inside bottom  28  and an inside top  26 . The inside shell  24  is a vertical cylinder in the preferred embodiment and forms a chamber  36  therein where the fire is maintained. Protruding from the inside top  26  is a flue  22  that extends though the outside top  14 . A space  18  is created between inside shell  24 , inside bottom  28 , inside top  26  and outside shell  12 , outside bottom  16 , outside top  14 . A load door  38  and an ash door  40  protrude the front side of inside shell  24  to the outside through the outer shell  12 . Their relative position is shown in phantom, in this view. Load door  38  and ash door  40  serve as a means to access chamber  36 , for example, to add solid fuel and remove ash, respectively. Supports  44  serve as a means to elevate inside shell  24 , inside bottom  28  and inside top  26  within space  18 . Baffle supports  30  are fixed to the chamber  36  side of the inside shell  24  by welding or any other suitable means. Baffle  32  is comprised of two equal semi circle sections joined in the center by a ship lap connection. In this view the front of blowers/pumps  48  are visible. 
       FIG. 3  is a section view taken from  FIG. 2 . This view more clearly shows the circular configuration of the entire assembly. In particular are shown the baffles  32  having a diameter smaller than the diameter of the inside shell  24  so that a gap  50  is created along the perimeter of the baffles  32 . The baffles  33  may also include notches  34  that are taken from the edges of the baffle  32 . Positions of flue  22  and ducts  20  are shown in phantom in relation to the entire appliance. 
       FIG. 4  is another section view taken from  FIG. 2 . This view more clearly shows the position of the blowers/pumps  48 , positioned in their housing at the lower end of the outer shell  12 . Supports  44  are shown in their relative positions supporting inside bottom  28 . Deflectors  46  are positioned to direct air or fluid from blower/pump  48  to the front of the space  18 . 
       FIG. 5  shows the solid fuel burning appliance in operation. One uses the appliance in the normal manner by loading wood or other fuel through load door  38  into chamber  36 . Fuel is ignited and burns in the chamber  35 . For efficiency burn is controlled by draft regulators  42 . Exhaust gases do not have a direct route out the flue  22 . Exhaust gases are inhibited from traveling in an upward direction by baffles  32  and must continue their upward path around the baffles  32  through the gap between the baffles and the inner shell to escape through flue  22 . Flue  22  is set 1 to 2 inches below inside top  26 . The heat is dispersed better and the combustion flame is further inhibited from going up the flue  22  by the inset of flue  22 . 
     The vertical nature of flue  22  allows creosote to fall directly back into the furnace, not collecting in flue  22 . The baffle  32  will force the flame and exhaust to pass by the gap  50  between the Baffle  32  and the inside, of inside shell  24  causing the inside shell  24  to heat up. In turn the air or fluid in space  18  is heated and forced through ducts  20  by one or more blowers/pumps  48 , or induction and delivered to the area being heated. Blowers/pumps  48  are controlled by fan limit switches  52 . In the preferred embodiment, when the furnace first heats up one blower/pump  48  will turn on. Once the appliance is hot it will turn on the other blower/pump  48 , produce more air or fluid flow and deliver more heat. As the appliance cools down one blower/pump  48  will shut off, with less air or fluid flow. You get the same air or fluid temperature from the appliance but less volume of air or fluid. The exact on and off temperatures may be selected to achieve the desired temperature in the space being heated and/or preferably for controlling the fire in the furnace. In one embodiment there can be a two speed blower/pump  48  that can switch from low speed to high speed or from high speed to low speed automatically. 
     Operating in this way keeps the appliance at a steady temperature and makes the actual fire in the furnace last longer because the chamber  36  will maintain a constant temperature and thus allow the rest of the heat to transfer to the heat exchanger and space  18 . In the preferred embodiment, fan limit switches  52  are instrumental to the movement of cold air or fluid over the chamber  36 . If you move too much cold air or fluid over the chamber  36  the heat from the fire will heat inside shell  24 , inside bottom  28 , and inside top  26 , not transferring any heat into the heat exchanger and space  18 . 
     The vertical cylindrical shape of inside shell  24  and outside shell  12  equalizes the heat, pressure and their transference from the inside walls of inside shell  24  and outside shell  12 . Corners are eliminated in the preferred embodiment thus eliminating dead spaces created by corners. A more economical and efficient heat distribution is achieved. 
     In the preferred embodiment, the baffle  32 , being circular, can be mounted with a plurality of supports  30 . The baffle  32  being constructed in two sections can easily be inserted or removed, a section at a time, in and out of load door  38 . As each section of baffle  32  is inserted into chamber  36  they are mutually joined in a ship lap fashion, raised into position with notches  34  clearing supports  30  and rotated until baffle  32  rests on supports  30 . Supports  30  as shown in  FIG. 2  are configured in a right angle shape. The material thickness in the vertical leg of the angle of support  30  serves to self center the baffle  32 . Thus inhibiting the baffle  32  from touching inside shell  24  and preventing hotspots and eventual warping of the inside shell  24 . A gap  50  range of 0.25 inch to 2 inches is maintained. 
       FIG. 6  shows a fire grate  54  for use in the fire chamber. The fire grate  54  is generally located a certain height above the bottom of the inner shell. Holes in the grate allow ash to fall through the grate and settle to the bottom of the inner shell where the ash can be removed from the ash door. In one embodiment, the grate  54  is made up of two outer fire grate halves  56 ,  58  that allow the grate  54  to be placed into the fire chamber through at least one of the doors. The fire grate  54  may include a center fire grate  60  section that can be rotated and mounted in the middle of the outer fire grate halves  56 ,  58 . This allows the inner fire grate  60  to be rotated in the fire chamber to cause ash to fall to the bottom of the inner shell. In at least one embodiment, the three piece fire grate  54  that has a two piece constructed exterior circumference design with a ship lap construction that would accept a circular center piece section  60  that is constructed with a ship lap exterior edge to allow, once all assembled, a twisting or shaking action of the center section  60  that will travel by the support of the outside grate sections  56  and  58   
     ADVANTAGES 
     An advantage of this invention in one embodiment or variant of the invention is to provide a device for efficiently distributing heat from wood or other fuel. 
     Another advantage of this invention in one embodiment or variant of the invention is to provide a device of a more economical construction. 
     Another advantage of this invention in one embodiment or variant of the invention is to provide a device that does not accumulate deposits from flue gases. 
     Another advantage of this invention in one embodiment or variant of the invention is to provide a device without a hot spot in the back. 
     Another advantage of this invention in one embodiment or variant of the invention is to provide a device without hot or cold spots. 
     Another advantage of this invention in one embodiment or variant of the invention is to provide a device with more longevity from operational burnout deterioration. 
     Another advantage of this invention in one embodiment or variant of the invention is to provide a device with heat baffles that can be serviced through the furnace&#39;s load door. 
     Another advantage of this invention in one embodiment or variant of the invention is to provide a device with self centering heat baffles. 
     Another advantage of this invention in one embodiment or variant of the invention is to provide a device that ensures against eventual operational warping of the fire chamber. 
     Another advantage of this invention in one embodiment or variant of the invention is to provide a furnace with a smaller size than a rectangular furnace while having the same BTU rating. 
     Another advantage of this invention in one embodiment or variant of the invention is to provide a furnace that requires less steel to construct and less solid fuel to heat the chamber to adequate delivery temperature. 
     From the description above, a number of advantages of some embodiments of my wood burning furnace become evident: 
     There are many materials and configurations that can be used in constructing the invention by those skilled in the art including various materials, methods and dimensions. In addition, it is clear that an almost infinite number of minor variations to the form and function of the disclosed invention could be made and also still be within the scope of the invention. Consequently, it is not intended that the invention be limited to the specific embodiments and variants of the invention disclosed. It is to be further understood that changes and modifications to the descriptions given herein will occur to those skilled in the art. Therefore, the scope of the invention should be limited only by the scope of the claims.