High efficiency bio-fuel pellet and grain furnace

Abstract

A high efficiency bio-fuel pellet and corn burning furnace. The furnace has a series of augers to load the fuel into the burn pot, move the fuel through the burn pot and finally remove the ash from the system. The burn pot or combustion area as two parallel augers with counter rotating flights so as to move the combustible material towards the area between the burn pot augers and from one side of the burn pot to the other during combustion so as to prevent clumping and aid in complete combustion.

Description

BACKGROUND OF THE INVENTION

The present invention relates to an improvement in the manner employed to burn bio-fuel pellets or grain in a furnace. More specifically, in the design of the burn pot employed in bio-fuel pellet or grain furnaces that both agitate the fuel and inhibit the formation of fuel clumps thereby encouraging the complete combustion of the fuel and increasing the overall efficiency.

With the ever increasing rise in energy costs the search for alternative fuel sources has accelerated in the past few years. While this search is showing promise in highly visible areas such as wind and solar power, it has also resulted in improved methods of exploiting existing yet underutilized fuels such as wood and its derivative products or other solid bio-fuels. These fuel sources are especially important in the heating of buildings such as homes or small businesses as their design and manner of operation lend themselves to these applications. However, it must also be noted that these heating systems are capable of being adapted for use with larger structures. In fact, it is becoming more common for relatively large public institutions such as prisons to use these systems.

The use of wood or other solid bio-fuel for heating is most commonly accomplished in one of two ways. The first of these is to burn it in a furnace or wood stove that is contained within the heated building. In this method of use, the burning fuel is used to warm the space simply through radiant heating, to heat up a volume of air which is then circulated by an additional means throughout the desired space, or to heat water that is then circulated to remote heat exchange units. While these methods do accomplish the desired effect, they are generally very inefficient and wasteful.

The second common way of heating with wood or other solid bio-fuel is the use of a self contained outdoor furnace in which the burning fuel is used to heat water. Once the water has reached the desired predetermined temperature, it is transferred to the building to be used as the needed heat source. The heated water is employed within the structure in conjunction with the building's existing heating system. In the case where the building employs an existing hot water heating system, the heated water from the external furnace is employed to heat the existing system's water through a water to water heat transfer unit. In the case of an existing forced air furnace, the heated water is pumped through a water to air heat exchanger which in turn heats the circulated air. Finally, the heated water of the external furnace can also be used to heat the water used within the building that is used for domestic purposes by the use of an additional water to water heat exchanger that is fitted to the existing hot water heater.

The use of the external self-contained heating units has several advantages over the internal styles. The first of these is that they are vastly more efficient then the majority of the stove or furnace counterparts. Secondly, positioning the furnace outside of the building removes the mess—most notably ash and other combustion residue associated with the burning of solid bio-fuels—from its interior. The outdoor furnaces also eliminate the dangers associated with the burning of any heating fuel within an inhabited building.

While in general terms most of the existing outdoor furnaces employ wood as a fuel source, there is an increasing trend in the use of bio-fuel pellets. Bio-fuel pellets are a good choice for use in these furnaces as they have similar BTU content as wood fuel but offer many advantages in comparison. In response to this, furnaces have been redesigned for use specifically with bio-fuel pellets. The primary differences in the two types of furnaces involve the design of the burn pot and the incorporation of fuel delivery systems in the furnaces. Also, the use of pelletized bio-fuels provides the additional advantage of allowing for the continuous feeding of the fuel into the burn chamber eliminating the need of manually adding fuel on a periodic basis.

Another advantage offered by the use of outdoor furnaces that burn bio-fuel pellets is that they can be made of a variety of differing base materials. The most common of these is the sawdust generated as a byproduct of sawmills that is compressed into pellets of the desired size and shape. This method of generating a bio-fuel has the added advantage of reducing pressure on landfills as prior to the development-of the wood-based fuel pellet, sawdust was commonly considered to be waste and was disposed of in the local landfill. Similarly, bio-fuel pellets can also be produced from paper waste offering the same advantages as sawdust.

An alternative to these two fuel sources is the use of grains, most commonly corn, as a fuel source either in its natural state or processed into pellets. Again, grains have a similar BTU profile with respect to both the wood based bio-fuel pellets and wood. The use of grain, however, does provide important advantages. The ability of these furnaces to burn a variety of bio-fuels provides a degree of flexibility to their use. This flexibility allows the user to alter the fuel source thereby making it possible to take advantage of alterations of availability and cost of differing fuels. Also, the fact that the grain can be burned without any processing beyond drying can further decrease the overall costs of operating these outdoor bio-fuel furnaces.

While outdoor furnaces specifically designed to employ bio-fuel pellets or grains exist in the prior art, they all suffer from one glaring deficiency. They lack the ability to ensure that the bio-fuel pellets or grains are completely burned in a consistent manner. This problem stems from the design of the prior art's furnace burn pots and the bio-fuel pellet's tendency to clump or stick together during combustion. This characteristic leads to a situation in which the fuel contained within a burn pot does not completely burn resulting in inherent inefficiencies. Since the burn pots of the prior art are designed simply to hold the burning bio-fuel pellets until they are reduced to ash, there is no mechanism to counteract the tendency of the burning bio-fuel pellets or grains to form clumps.

Therefore, it can be seen that it would be desirable to provide an external heating furnace that is designed to operate with existing heating systems and is capable of using bio-fuel pellets or grains as a fuel source. Additionally, it can be seen that it would be desirable to incorporate a burn pot within such a furnace that is specifically designed to eliminate the clumping problem that commonly occurs during the combustion of the bio-fuel pellets or grains.

SUMMARY OF THE INVENTION

It is the primary objective of the present invention to provide an external heating furnace that is designed to burn bio-fuel pellets or grains as a fuel source and that is used to heat water that is then used in conjunction with a building's existing heating system to provide the necessary heat.

It is an additional objective of the present invention to provide such a furnace that is designed in such a manner so that the bio-fuel pellets or grains can be continuously and automatically fed into the furnace thereby eliminating the need for the user to constantly add fuel.

It is a further objective of the present invention to provide such a furnace that employs the use of a specially designed burn pot that eliminates the clumping normally associated with the combustion of bio-fuel pellets or grains thereby increasing the efficiency of the furnace as used with these fuel sources.

It is a still further objective of the present invention to provide such a furnace that is designed so that the ash created by the combustion of the bio-fuel pellets or grains are automatically and continuously removed from the interior of the furnace ensuring cleaner and more efficient operation.

These objectives are accomplished by the use of a bio-fuel pellet and grain furnace that is designed to provide the necessary heating needs to a building while being positioned outside of it. In the accomplishment of this, the present invention is constructed having an exterior furnace housing that protects its functional elements and improves its aesthetic characteristics. The latter is desirable due to its visibility being located outside of an existing structure.

The furnace housing of the present invention is generally a small shed-like structure that encloses the furnace unit and that contains front and rear access doors to provide the user with the necessary access to the operational components of the present invention. Additionally, the furnace housing also provides for the point of attachment for the fuel hopper. The fuel hopper is a relatively large storage bin into which the bio-fuel pellets or grains are placed and which allows for the continuous and automatic feeding of the fuel into the furnace. The positioning of the fuel hopper on the outer surface of the furnace housing provides for its easy access thereby allowing the user to fill it in a quick and efficient manner. Finally, the furnace housing also allows for the positioning of the control panel in a position that is easily accessible further enhancing the ease of operation of the present invention.

The primary component of the present invention is the furnace unit that is contained within the furnace housing. The furnace unit is made up of a horizontally oriented cylindrical drum which is capped at both ends by vertical end plates. The visible cylindrical portion is the outer surface of the furnace's jacket outer shell. The actual fire chamber of the furnace is located within the center of the furnace unit and its outer dimensions are defined by the jacket inner shell. The jacket outer and inner shells are then separated by a space that completely surrounds the jacket inner shell. This space is the water jacket through which water is circulated and heated through its contact with the outer surface of the jacket inner shell.

Additionally, the heating of the water is also facilitated by the incorporation of a plurality of heat exchange tubes which pass through the water jacket. The heat exchange tubes increase the amount of surface area through which the heat generated within the fire chamber can be transferred to the water being circulated through the water jacket.

The jacket end plate located on the forward end of the furnace unit in relation to the furnace housing is equipped with a furnace door. The furnace door provides the user with access to the fire chamber to allow for the starting of a fire within the burn pot or other maintenance purpose.

The rear jacket end plate also provides for the positioning of a number of components that are critical to the operation of the present invention. The first of these is the exhaust chamber which collects the exhaust gases coming from the fire chamber through the heat exchange tubes and directs them into the connected chimney. The second component is the drive system that powers the plurality of augers that are incorporated into the design of the present invention. The drive system and its related components will be discussed in greater detail below.

The rear end plate also provides for the point of attachment for the ash removal system and its related components. The ash removal system automatically and effectively removes any combustion residues from their point of collection at the bottom of the fire chamber and deposits them in the ash box. This is accomplished by the use of the ash auger that is powered by the drive system and extends through the bottom of the present invention's fire chamber. As the ash auger is rotated, it draws any ash towards the ash tube that extends through the rear end plate. This allows the ash to be removed from the invention to the ash box thereby ensuring that the fire chamber will remain clean and free of ash enabling the present invention to operate in the manner it was designed.

Finally, the rear end plate also provides for the positioning of the components of the present invention that deliver the fuel to the fire chamber. The first of these is the feed tube that extends from the lower portion of the fuel hopper diagonally upward to the transfer tube. Again, the drive system of the present invention drives a feed auger positioned within the feed tube which in turn draws the fuel up to the transfer tube that then takes the fuel into the fire chamber. This system allows for the delivery of fuel to the fire chamber for the necessary combustion.

As previously stated, the drive system of the present invention provides the rotational power that is necessary for operation. The drive motor's connection to the remaining components of the drive system is accomplished through the burn pot auger chain. The burn pot auger chain runs from a gear located on the front of the drive motor to the burn pot auger gears and an idler gear. The burn pot auger gears are fixedly attached to the outer ends of the burn pot augers that extend into the burn pot, a configuration that will be described in greater detail below.

From the burn pot auger gears, the burn pot auger chain engages an idler gear before returning to the drive motor. This configuration not only supplies the rotational power necessary to drive the burn pot augers, but also to drive the idler gear and all the other components that are attached to it. The idler gear is mounted on the inner end of an idler shaft which in turn has two more idler gears attached to it, one near its center and one on its outer end. The idler gear located on the outer end of the idler shaft is aligned with and connected to a similar gear on the end of the ash auger by the use of the ash auger chain. This configuration rotationally powers the ash auger providing the means to remove ash from the interior of the present invention. Finally, the idler gear that is centrally positioned on the idler shaft is aligned with and connected to the feeder gear by the use of the feeder chain. These components operate to supply the rotational power necessary to draw the fuel from the fuel hopper to the transfer tube and then to move it into the burn pot of the present invention.

As previously stated, the design and manner of operation of the burn pot are the principal components of the present invention. As such, the burn pot is an elongated U-shaped pan through which extend in a longitudinal manner the burn pot augers. Additionally, the burn pot augers are positioned within the burn pot so that they can engage and agitate any fuel that is contained within the burn pot. Finally, the outer surface of the burn pot is configured with a plurality of ventilation holes the purpose of which is to allow more air into the burn pot during the combustion of fuel thereby ensuring the highest possible efficiency.

The burn pot augers are actually made up of two separate augers, the clockwise and counterclockwise rotating augers. The clockwise and counterclockwise rotating augers are very similar in their manner of construction only differing in the direction of the twist of their screw-like components. This manner of construction means that even though they are rotating in the same general direction, they will impart opposite forces upon any material that comes into contact with them—notably, the bio-fuel pellets or grains.

The point of this is that the rotation of the burn pot augers will act mechanically on the fuel in the burn pot in two ways. The first of these is to move the fuel towards the center of the burn pot. This process will cause the individual bio-fuel pellets to come into contact with each other resulting in the agitation of the burning fuel. The agitation not only serves to increase the efficiency of the burning process by increasing the surface area of the fuel pellets that are directly exposed to the actual burning process, but also eliminates any clumping as the agitation breaks up any forming or existing clumps. Therefore, the design and positioning of the burn pot augers greatly enhances the burning characteristics of pellet burning furnaces making them one of the most efficient ways of producing the heat necessary for life.

The second mechanical action imparted on the burning fuel by the rotation of the burn pot augers is to move the burning fuel from the input end of the burn pot to the out end. While this lateral movement of the fuel acts on it in a manner that helps facilitate its complete combustion, it also serves to move the end products of the combustion process to the output end of the burn pot where they are removed to the lower portion of the fire chamber by the means of the ash exit hole in the burn pot end plate.

As previously stated, the present invention is controlled through the use of the control panel. The control panel contains a plurality of switches and two sets of timers. The switches control the exterior light and an internal fan. The timers are the components that control the operational aspects of the present invention and comprise a pair of primary timers and a pair of secondary timers. In the heating mode, the first primary timer, T1, controls the amount of time that the fuel feed and transfer augers run which in turn supply fuel to the burn pot. Additionally, the burn pot augers and ash auger also run during this period of time. The longer the time period dictated by the setting of T1, the longer the fuel will be supplied and the hotter the present invention will operate. The second primary timer, T2, then controls amount of time that T1 is turned off thereby also affecting the amount of heat produced by the present invention The secondary timers, T3 and T4, allow the present invention to operate in idle mode when heat is not needed but it is desirable to keep the present invention operating such as the warmer portion of the day. In the completion of this function, T3 and T4 operate in the same manner as T1 and T2 but supply only enough fuel to keep the present invention lit. The use of the T3 and T4 system eliminates the need for the operator to manually relight the present invention in weather conditions where heat is not needed in all parts of the day.

An additional embodiment of the present invention has been contemplated in which an automated fuel ignition system is incorporated into the burn pot. The use of the automated fuel ignition system would eliminate the need for the T3 and T4 system and thereby simplify the operation of the present invention.

For a better understanding of the present invention reference should be made to the drawings and the description in which there are illustrated and described preferred embodiments of the present invention.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the present invention illustrating the manner of construction of the furnace housing component and the position of the fuel hopper relative to other exterior feature.

FIG. 2 is a side elevation view of the present invention of FIG. 1 further defining the positioning of its fuel hopper component.

FIG. 3 is a front elevation view of the present invention of FIG. 1 illustrating the positioning of the furnace door.

FIG. 4 is an additional side elevation view of the present invention of FIG. 1 illustrating one possible location of the control panel.

FIG. 5 is a rear elevation view of the present invention of FIG. 1 illustrating the location and manner of construction of the rear access door.

FIG. 6 is a side elevation cut-away view of the present invention taken along LINE 3 of FIG. 5 and illustrating the general manner of construction of the interior components of the furnace unit and the orientation with respect to each other.

FIG. 7 is a rear elevation view of the furnace unit component of the present invention illustrating the manner of construction of its exhaust, drive, and ash removal systems.

FIG. 8 is a closeup front elevation view of the drive system of the present invention illustrating the manner of construction of its major components.

FIG. 9 is a closeup side elevation view of the drive system component of the present invention of FIG. 8.

FIG. 10 is a side elevation cut-away view of the burn pot component of the present invention illustrating the general manner of its construction.

FIG. 11 is a top elevation view of the burn pot component of the present invention of FIG. 10.

FIG. 12 is a rear elevation view of the burn pot component of the present invention of FIG. 10.

FIG. 13 is a front elevation view of the control panel component of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, and more specifically to FIGS. 1, 2, 3, 4, 5 and 6, the bio-fuel pellet and grain furnace 10 is made up of an external furnace housing 38 that encloses the functional element of the present invention. There are two reasons for the use of the furnace housing 38. The first of these is that it provides a degree of protection for the moving components of the present invention. This is important because it is positioned outside of the structure to which it supplies heat and is therefore exposed to the elements. The second is that the furnace housing 38 improves the aesthetic characteristics of the present invention, an important consideration to many due to its positioning in an area that is often visible to the general public.

The furnace housing 38 component of the present invention is generally a small rectangular box shed-like structure that encloses the furnace unit 36. This rectangular box comprising the furnace housing 38 is made up of a roof 12 that encloses the upper area of the box and is vented by an upwardly extending chimney 14. The two side walls 16 comprise the long side of the rectangular box and serve as the mounting points for the fuel hopper 24 and the control panel 32, both of which may be positioned on one or the other of the side walls 16. The fuel hopper 24 is the component of the present invention that holds a supply of fuel for combustion within the furnace unit 36 and is connected to it by means of the feed tube 30 extending from its lowest point up into the interior of the furnace housing 38 in a diagonal manner. The positioning of the fuel hopper 24 on a side wall 16 of the furnace housing 38 provides for its easy access thereby allowing the user to fill it with fuel in a quick and efficient manner.

The side walls 16 of the furnace housing 38 also provide for the positioning of the control panel 32 in a position that is easily accessible further enhancing the ease of operation of the present invention. The control panel 32 is the component of the present invention that the operator employs to affect the operational parameters of the present invention and will be described in greater detail below with reference to an additional FIGURE.

The front wall 18 of the furnace housing 38 contains a centrally located furnace door 22 providing the user with access to the interior of the furnace unit 36. The furnace door 22 allows the user to perform critical functions pertaining to the operation of the present invention such as igniting the fuel, cleaning, and any other maintenance needs. The front wall is also commonly equipped with an exterior light 28 that is controlled from the control panel 32 and provides needed light to the exterior of the present invention. Finally, the rear wall 20 of the furnace housing 38 is equipped with a rear access door 34. The rear access door 34 provides the user with the necessary access to the operational components of the present invention contained within the furnace housing 38.

The primary component of the present invention is the furnace unit 36 that is contained within the furnace housing 38 and which is further illustrated in FIGS. 6 and 7. The furnace unit 36 is made up of a horizontally oriented cylindrical drum which is capped at both ends by vertical jacket end plates 43. The jacket end plates 43 operate both to enclose the ends of the furnace unit 36 and to provide for the attachment of a plurality of the present invention's components. Among these are the furnace legs 26 that are attached to the outer surfaces of the jacket end plates 43 and which extend downward in an outwardly oriented diagonal manner beyond the lower surface of the furnace housing 38. The furnace legs 26 function to support the present invention and to position it in a desirable position relative to the surface that it rests on.

The visible cylindrical portion of the furnace unit 36 disregarding the furnace housing 38 is the outer surface of the furnace's jacket outer shell 42. The jacket outer shell operates to contain all of the furnace unit's internal components. The actual fire chamber 46 of the furnace is located within the center of the furnace unit 36 and its outer dimensions are defined by the jacket inner shell 44. The jacket outer and inner shells, 42 and 44, are then separated by an open space that completely surrounds the jacket inner shell 44. This space is the water jacket 40 through which water is circulated and heated through its contact with the outer surface of the jacket inner shell 44.

Additionally, the heating of the water is also facilitated by the incorporation of a plurality of heat exchange tubes 54 which pass through the water jacket 40. The heat exchange tubes 54 are effectively modifications of the upper portion of the furnace's fire chamber 46 through which the exhaust gases are directed prior to exiting the furnace unit 36. The heat exchange tubes 54 operate to increase the amount of surface area through which the heat generated within the fire chamber can be transferred to the water being circulated through the water jacket. Additionally, the heat exchange tubes 54 are each equipped with flow disruptors 65 that impart a swirling motion to the exhaust gases as they pass through the heat exchange tubes 54. This swirling motion ensures that the hottest portions of the exhaust gas are in contact with the outer walls of the heat exchange tubes 54 thereby increasing the heat transfer to the water in the water jacket 40.

The jacket end plate 43 located on the forward end of the furnace unit 36 in relation to the furnace housing 38 is equipped with a furnace door opening 47. The furnace door opening 47 operates in conjunction with the furnace door 22 and provides the user with access to the furnace fire chamber 46 to allow for the starting of a fire within the burn pot 48 or other maintenance purposes.

The rear jacket end plate 43 also provides for the positioning of a number of components that are critical to the operation of the present invention. The first of these is the exhaust chamber 64 which collects the exhaust gases coming from the furnace fire chamber 46 through the heat exchange tubes 54 and directs them into the connected chimney 14. The most rearward portion of the exhaust chamber 64 is equipped with a chamber door 66 that allows access to its interior for maintenance purposes such as cleaning.

The second component positioned on the rear jacket end plate 43 is the drive system 55 that powers the plurality of augers that are incorporated into the design of the present invention and that are pivotal to its operation. The drive system 55 and its related components will be discussed in greater detail below with reference to additional FIGURES.

The rear jacket end plate 43 also provides for the point of attachment for the ash removal system 57 and its related components. The ash removal system 57 automatically and effectively removes any combustion residues from their point of collection at the bottom of the furnace fire chamber 46 and deposits them in the ash box 56. The ash box 56 provides a collection point for the removed ash and can be easily cleaned by opening it and removing the contained ash. The removal of the ash from the ash box 56 is accomplished by the use of the ash auger 52 that is powered by the drive system 55 and extends through the bottom of the furnace's fire chamber 46. As the ash auger 52 is rotated, it draws any ash towards the ash tube 58 that extends through the rear jacket end plate 43. Once the ash exits the furnace fire chamber 46 it is dumped into the ash box 56 for removal at a later time. This allows the ash to be automatically removed from the invention thereby ensuring that the furnace fire chamber 46 will remain clean and free of ash enabling the present invention to operate in the manner it was designed.

Finally, the rear jacket end plate 43 also provides for the positioning of the components of the present invention that delivers the fuel to the furnace fire chamber 46. The first of these is the feed tube 30 that extends from the lower portion of the fuel hopper 24 diagonally upward to the transfer tube 62. Again, the drive system 55 of the present invention drives a feed auger 86 positioned within the feed tube 30 which in turn draws the fuel up to the transfer tube 62 that then takes the fuel into the furnace fire chamber 46. This system allows for the delivery of fuel to the furnace fire chamber 46 for the necessary combustion.

As previously stated, the drive system 55 of the present invention provides the rotational power that is necessary for operation and is further illustrated in FIGS. 8 and 9. The primary component of the drive system 55 is the drive motor 60. The dive motor 60 is attached to the rear jacket end plate 43 by the use of the drive motor bracket 90 which positions it in the proper position relative to the remaining components of the drive system 55.

The drive motor's 60 connection to the remaining components of the drive system 55 is accomplished through the burn pot auger chain 74. The burn pot auger chain 74 runs from a gear (not shown) located on the front of the drive motor 60 to the burn pot auger gears 72 and an idler gear 76. The burn pot auger gears 72 are fixedly attached to the outer ends of the burn pot augers 50 that extend into the burn pot 48, a configuration that will be described in greater detail below.

From the burn pot auger gears 72, the burn pot auger chain 74 engages an idler gear 76 before returning to the drive motor 60. This configuration not only supplies the rotational power necessary to drive the burn pot augers 50, but also to drive the idler gear 76 and everything attached to it. The idler gear 76 is mounted on the inner end of an idler shaft 82 which in turn has two more idler gears 76 attached to it, one near its center and one on its outer end. The idler shaft 82 is mounted to the upper surface of the ash tube housing 59 that anchors the outer end of the ash auger 52. This mounting is accomplished by a pair of shaft housings 84 that rotationally attach the idler shaft 82 in the desired position relative to the remaining components of the drive system 55.

The idler gear 76 located on the outer end of the idler shaft 82 is aligned with and connected to a similar ash auger gear 78 on the end of the ash auger 52 by the use of the ash auger chain 80. This configuration rotationally powers the ash auger 52 providing the means to remove ash from the interior of the present invention through the ash tube 58 passing through the rear jacket end plate 43.

The idler gear 76 that is centrally positioned on the idler shaft 82 is aligned with and connected to the feeder gear 68 by the use of the feeder chain 70. These components operate to supply the rotational power necessary to draw the fuel from the fuel hopper 24 to the transfer tube 62 and then to move it into the burn pot 48 of the present invention by means of the rotation of the transfer auger 88 positioned within the transfer tube 62. This system of interconnected gears and chains transfers the rotational power of the drive motor 60 to all of the relevant components of the drive system 55 while also ensuring that they all operate in conjunction with one another and for the same amount of time.

As previously stated, the design and manner of operation of the burn pot 48 are the key elements of the present invention and are further detailed in FIGS. 10, 11, and 12. As such, the burn pot 48 is an elongated U-shaped pan through which extend in a longitudinal manner the burn pot augers 50. Additionally, the burn pot augers 50 are positioned within the burn pot 48 so that they can engage and agitate any fuel that is contained within the burn pot 48. Finally, the outer surface of the burn pot is configured with a plurality of ventilation holes 94, the purpose of which is to allow more air into the burn pot 48 during the combustion of fuel thereby ensuring the highest possible efficiency.

The burn pot augers 50 are actually made up of two separate augers units, the clockwise and counterclockwise rotating augers, 96 and 98. The clockwise and counterclockwise rotating augers, 96 and 98, are very similar to each other in their manner of construction only differing in the direction of the twist of their screw-like components. This manner of construction means that even though they are rotating in the same general direction, they will impart opposite forces upon any material that comes into contact with them—notably, the bio-fuel pellets.

The point of this is that the rotation of the burn pot augers 50 will act mechanically on the fuel in the burn pot 48 in two ways. The first of these is to move the fuel towards the center of the burn pot 48. This process will cause the individual bio-fuel pellets to come into contact with each other resulting in the agitation of the burning fuel. The agitation not only serves to increase the efficiency of the burning process by increasing the surface area of the fuel pellets that are directly exposed to the actual burning process, but also eliminates any clumping as the agitation breaks up any forming or existing clumps. Therefore, the design and positioning of the burn pot augers 50 greatly enhances the burning characteristics of pellet burning furnaces making them one of the most efficient ways of producing the heat necessary for life.

The second mechanical action imparted on the burning fuel by the rotation of the burn pot augers 50 is to move the burning fuel from the input end 63 of the burn pot to the output end 93. While this lateral movement of the fuel acts on it in a manner that helps facilitate its complete combustion, it also serves to move the end products of the combustion process to the output end 93 of the burn pot 48 where they are removed to the lower portion of the furnace fire chamber 46 by the means of the ash exit hole 104 in the burn pot end plate 92.

As briefly described above, the present invention is controlled through the use of the control panel 32 which is further detailed in FIG. 13. The control panel 32 contains a plurality of switches and two sets of timers. The light switch 108 controls the exterior light 28 and the fan switch 106 operates an internal fan. The control panel 32 also contains a water level light 110 that will warn the operator if the water level in the present invention drops to a dangerously low level. This is an important safety feature as it will provide a warning of an unsafe water level that could result in the present invention over heating.

More importantly to the operation of the present invention, the timers control the operational aspects of the present invention and comprise a pair of primary timers 112, T1 114 and T2 116, and a pair of secondary timers 118, T3 120 and T4 122. In the heating mode, T1 114 controls the amount of time that the fuel feed auger 86 and transfer auger 88 run which in turn supply fuel to the burn pot 48. Additionally, the burn pot augers 50 and ash auger 52 also run during this period of time. The longer the time period dictated by the setting of T1 114, the longer the fuel will be supplied and the hotter the present invention will operate. The second primary timer, T2 116, then controls amount of time that T1 114 is turned off thereby also affecting the amount of heat produced by the present invention.

The secondary timers 118, T3 120 and T4 122, allow the present invention to operate in idle mode when heat is not needed but it is desirable to keep the present invention operating such as the warmer portion of the day. In the completion of this function, T3 120 and T4 122 operate in the same manner as T1 114 and T2 116 but supply only enough fuel to keep the present invention lit. The use of the secondary timer 118 system eliminates the need for the operator to manually relight the present invention in weather conditions where heat is not constantly needed. Finally, a digital display 124 is positioned between the primary and secondary timers, 112 and 118. The digital display 124 allows the operator to monitor the functions of the present invention.

An additional embodiment of the present invention has been contemplated in which an automated fuel ignition system (not illustrated) is incorporated into the burn pot 48. The use of the automated fuel ignition system would eliminate the need for the secondary timer 118 system and thereby simplify the operation of the present invention.

Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.

Claims

1. A solid bio-fuel burning furnace that uses bio-fuel pellets, corn, or other similarly shaped combustible material for fuel said furnace comprising:

an elongate burn pot for containing said fuel during combustion said burn pot having a first and second end;

a feed auger for moving said fuel into said first end of said burn pot from outside of said burn pot; and

a first elongate auger in said burn pot for moving fuel placed in said burn pot by said feed auger from said burn pots first end to said burn pots second end during combustion.

2. A solid bio-fuel burning furnace as in claim 1 wherein said elongate burn pot is substantially U-shaped in its cross section.

3. A solid bio-fuel burning furnace as in claim 2 wherein said burn pot further defines a plurality of ventilation holes for aiding the combustion of said fuel.

4. A solid bio-fuel burning furnace as in claim 3 further comprising a second elongate auger parallel to said first elongate auger in said burn pot for moving fuel placed in said burn pot by said feed auger from said burn pots first end to said burn pots second end during combustion.

5. A solid bio-fuel burning furnace as in claim 4 wherein said first elongate auger has a counterclockwise screw component and said second elongate auger has a clockwise screw component.

6. A solid bio-fuel burning furnace as in claim 5 wherein said second end of said burn pot defines an ash exit hole.

7. A solid bio-fuel burning furnace as in claim 6 further comprising an ash auger for moving ash that passes through said ash exit hole to an ash collection box.

8. A solid bio-fuel burning furnace as in claim 7 wherein said feed auger and said first and second elongate augers and said ash auger are connected via a chain drive system.

9. A solid bio-fuel burning furnace as in claim 8 further comprising a motor for driving said chain drive system.

10. A solid bio-fuel pellet and solid grain fuel burning furnace comprising:

an elongate burn pot for containing said fuel during combustion said burn pot having a first and second end;

a first elongate auger in said burn pot for moving fuel placed in said burn pot by said feed auger from said burn pots first end to said burn pots second end during combustion said first elongate auger having a counterclockwise screw component; and

a second elongate auger parallel to said first elongate auger in said burn pot for moving fuel placed in said burn pot by said feed auger from said burn pots first end to said burn pots second end during combustion said second elongate auger having a clockwise screw component so that said first and second auger work to move said fuel to the center of said burn pot from said burn pots first end to said burn pots second end.

11. A solid bio-fuel burning furnace as in claim 10 wherein said elongate burn pot is substantially U-shaped in its cross section.

12. A solid bio-fuel burning furnace as in claim 11 wherein said burn pot further defines a plurality of ventilation holes for aiding the combustion of said fuel and second end of said burn pot defines an ash exit hole.

13. A solid bio-fuel burning furnace as in claim 12 further comprising an ash auger for moving ash that passes through said ash exit hole to an ash collection box.

14. A solid bio-fuel burning furnace as in claim 13 further comprising a chain drive system connecting said first and second elongate augers and said ash auger.

15. A solid bio-fuel burning furnace as in claim 14 further comprising a motor for driving said chain drive system.

16. A solid bio-fuel pellet and solid grain fuel burning furnace comprising:

an elongate burn pot for containing said fuel during combustion said burn pot having a first and second end;

a feed auger for moving said fuel into said first end of said burn pot from outside of said burn pot;

a first elongate auger in said burn pot for moving fuel placed in said burn pot by said feed auger from said burn pots first end to said burn pots second end during combustion said first elongate auger having a counterclockwise screw component; and

a second elongate auger parallel to said first elongate auger in said burn pot for moving fuel placed in said burn pot by said feed auger from said burn pots first end to said burn pots second end during combustion said second elongate auger having a clockwise screw component so that said first and second auger work to move said fuel to the center of said burn pot from said burn pots first end to said burn pots second end.

17. A solid bio-fuel burning furnace as in claim 16 wherein said elongate burn pot is substantially U-shaped in its cross section.

18. A solid bio-fuel burning furnace as in claim 17 wherein said burn pot further defines a plurality of ventilation holes for aiding the combustion of said fuel and second end of said burn pot defines an ash exit hole.

19. A solid bio-fuel burning furnace as in claim 18 further comprising an ash auger for moving ash that passes through said ash exit hole to an ash collection box.

20. A solid bio-fuel burning furnace as in claim 19 further comprising a chain drive system connecting said feed auger and said first and second elongate augers and said ash auger and a motor from driving said chain drive system.