Patent Document

This non-provisional patent application hereby claims priority to U.S. Provisional Patent Application No. 61/527,962, titled Fireplace Assembly With Biomass Fuel Delivery System, filed Aug. 26, 2011, which is incorporated herein in its entirety by reference thereto. 
    
    
     TECHNICAL FIELD 
     The present invention is directed to biomass burning fireplace assemblies, and more particularly to such fireplace assemblies with a biomass fuel delivery system and related methods. 
     BACKGROUND 
     Conventional pellet-burning stoves and fireplace assemblies direct the wood pellets from a hopper  14  to a burn pot for combustion. There is a need for improvements in, for example, better fuel delivery, burn rate control, fuel selection, efficiency, and/or other operational functions. 
     SUMMARY 
     The present invention provides a biomass-burning fireplace assembly (including fireplaces, stoves, and inserts) and related methods that overcome drawbacks experienced in the prior art and that provide additional benefits. The present invention is also directed to a fuel delivery system for a biomass-burning fireplace assembly. At least one aspect of the disclosure is directed to a biomass-burning fireplace assembly comprising a firebox having a fuel inlet opening, and a hopper configured to contain a biomass fuel. The hopper has a hopper inlet and a hopper outlet. A barrier member is adjacent to the hopper outlet, and a fuel metering assembly is adjacent to the hopper outlet. The fuel metering assembly has a fuel metering receptacle that receives the biomass fuel from the hopper, and the fuel metering receptacle is moveable relative to the hopper outlet between first and second positions. The fuel metering receptacle in the first position is on a first side of the barrier member and arranged to receive the biomass fuel from the hopper outlet. The fuel metering receptacle in the second position is on second side of the barrier member and out of alignment with the hopper outlet. The barrier member is a physical barrier between the fuel metering receptacle and the hopper outlet. A fuel feed assembly having a feed inlet positioned is in alignment with the fuel metering receptacle when the fuel metering receptacle is in the second position to receive the biomass fuel from the fuel metering assembly, wherein the feed inlet is blocked from the hopper outlet by at least a portion of the barrier member to avoid a fire path to the hopper. The fuel feed assembly has a fuel feed outlet in communication with the fuel inlet opening in the fire box and having a fuel advancing member disposed between the fuel feed inlet and fuel feed outlet and is configured to move the biomass fuel out the fuel feed outlet and through the fuel feed inlet of the firebox. A burn platform assembly is coupled to the firebox and positioned adjacent to the fuel inlet opening. The burn platform has a support surface that receives the biomass fuel received from the fuel feed assembly. 
     The fuel metering assembly can include a metering disk rotatably disposed relative to the hopper outlet, wherein the fuel metering disk has the fuel metering receptacle disposed therein, and wherein rotation of the metering disk moves the fuel metering receptacle between the first and second positions. The fuel metering assembly can include a drive motor operatively coupled to the metering disk and configured to rotate the fuel metering disk. The fuel metering receptacle can include first and second metering receptacles each being moveable between the first and second positions. The first fuel metering receptacle can be in the first position when the second fuel metering receptacle is in the second position. The fuel metering assembly can include a drive motor coupled to the metering member that has the fuel metering receptacle therein, and the drive motor can be configured to move the metering member relative to the hopper outlet. The barrier member can engage the metering member when the metering member moves the fuel metering receptacle between the first and second positions. The barrier member can rotate about a central axis when the metering member moves the fuel metering receptacle between the first and second positions. The fuel feed assembly can include a housing, and the fuel advancing member can be an auger member rotatable disposed in the housing, wherein rotation of the auger member advances the biomass fuel from the fuel feed inlet to the fuel feed outlet. 
     In at least another aspect of the present disclosure, a fireplace assembly has a housing, a firebox having a fuel inlet opening, and a fuel hopper configured to contain a solid fuel therein. The hopper has a hopper outlet adjacent to the fuel inlet opening. A fuel metering assembly is adjacent to the hopper outlet, and the fuel metering assembly has a fuel metering receptacle configured to receive the solid fuel from the hopper. The fuel metering receptacle is moveable relative to the hopper outlet between first and second positions. The fuel metering receptacle in the first position is arranged to receive the solid fuel from the hopper outlet. The fuel metering receptacle in the second position is out of alignment with the hopper outlet and out of communication with the hopper outlet to prevent a potential fire path to the hopper. A fuel feed assembly has a feed inlet positioned in direct communication with the fuel metering receptacle in the second position. The fuel feed assembly has a fuel feed outlet in communication with the fuel inlet opening in the fire box and has a fuel advancing member configured to move the solid fuel out the fuel feed outlet and through the fuel feed inlet of the firebox. A burn platform assembly is coupled to the firebox and positioned adjacent to the fuel inlet opening. The burn platform has a support surface that receives the solid fuel received from the fuel feed assembly for burning of the solid fuel in the fire box while on the support portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view of a fireplace assembly with a fuel delivery system in accordance with an embodiment of the present invention. 
         FIG. 2  is an enlarged isometric view of a front side of the fireplace assembly of  FIG. 1 . 
         FIG. 3  is an enlarged top isometric view of the fireplace assembly of  FIG. 1  with a top plate removed to show a hopper assembly. 
         FIG. 4  is an enlarged isometric view of the fireplace assembly of  FIG. 3  with the hopper assembly removed to show a fuel metering assembly. 
         FIG. 5  is an enlarged bottom view of the hopper assembly of  FIG. 4 . 
         FIG. 6  is an enlarged top view of the fuel metering system of  FIG. 4 . 
         FIG. 7  is an enlarged front view of the fireplace assembly of  FIG. 2  showing a portion of the fuel metering system in a fire box of the fireplace assembly. 
         FIG. 8  is an enlarged front isometric view of a portion of the fuel metering assembly in the fire box of the fireplace assembly of  FIG. 7 . 
         FIG. 9  is an enlarged front isometric view of the fireplace assembly with a fuel delivery assembly of  FIG. 1 , with a control system shown in a raised position. 
         FIG. 10  is an isometric view of the fuel metering assembly of  FIG. 6  shows removed from the fireplace assembly. 
         FIG. 11  is an enlarged isometric view of a fuel metering disc of the fuel metering assembly of  FIG. 10 . 
         FIG. 12  is an enlarged isometric view of a feed auger assembly of the fuel metering assembly of  FIG. 10 . 
         FIG. 13  is an enlarged front isometric view of a burning platform assembly shown removed from the fuel metering assembly of  FIG. 10  and shown with a deflector removed. 
         FIG. 14  is an enlarged rear isometric view of the burn platform assembly of  FIG. 13 . 
         FIG. 15  is an enlarged front isometric view of the burn platform assembly of  FIG. 13 . 
         FIG. 16  is an enlarged isometric view of the deflector shown removed from the burn platform assembly of  FIG. 13   
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure describes a biomass-burning fireplace assembly  10  (including fireplaces, stoves, and inserts), a fuel delivery system  12  for a biomass-burning fireplace assembly  10 , and related methods in accordance with certain embodiments of the present invention. Several specific details of the invention are set forth in the following description and the Figures to provide a thorough understanding of certain embodiments of the invention. One skilled in the art, however, will understand that the present invention may have additional embodiments, and that other embodiments of the invention may be practiced without several of the specific features described below. 
       FIGS. 1-3  are isometric views of a biomass-burning fireplace assembly  10  in accordance with at least one embodiment includes fuel hopper  14  with an inlet  16  and outlet  18 . The hopper  14  is configured to contain a biomass fuel, such as wood pellets, wood chips, fruit pits, corn, other burnable biomass fuels, and combinations thereof), which will be efficiently burned in the fireplace assembly  10 , as discussed in greater detail below. The hopper  14  has an openable cover  20  on the hopper  14  to cover the inlet  16  and to block material from inadvertently getting into the hopper  14 . 
     The outlet  18  of the hopper  14  is an aperture sized to allow the biomass fuel exit the hopper  14  under the force of gravity. A guide  22  is attached to the bottom of the hopper  14  around the outlet aperture. The guide  22  has a substantially cylindrical bottom portion  24  and the outlet aperture is positioned above approximately one-half of the guide&#39;s circular cross section. The guide  22  has a wiper blade  26  formed by a blade seal  26  extending across the diameter of the cylindrical portion, such that the blade extends away from the hopper  14  and is generally adjacent to the hopper outlet aperture. Accordingly, the blade seal  26  divides the guide&#39;s bottom portion  24  in half, and fuel exiting the hopper  14  through the outlet  18  will pass through the guide  22  on only one side of the blade seal  26 . 
     A fuel metering assembly  28  is positioned below the hopper outlet  18  and adjacent to the blade seal  26 . The fuel metering assembly  28  includes a housing  32  with a cylindrical opening  34  shaped and sized to receive the cylindrical portion of the guide  22  in a close tolerance male/female fit. The fuel metering assembly  28  has a stationary base structure  36  with a fuel receiving opening  38  therein in alignment with the cylindrical opening  34  of the housing  32 , but the fuel receiving opening  38  is axially off set from the hopper&#39;s outlet aperture. Accordingly, when the fuel exits the hopper outlet  18 , the fuel will not fall via gravity directly into the fuel receiving opening  38 . In the illustrated embodiment, the hopper&#39;s outlet aperture and the cylindrical opening  34  of the housing  32  are axially offset on opposite sides of the blade seal  26 . 
     The fuel metering assembly  28  includes a fuel metering disc  40  rotatably attached to the housing  32  immediately adjacent to the base structure  36 . The fuel metering disc  40  has a thickness and at least one through hole that defines a fuel metering receptacle  42  shape and sized to contain a predetermined volume of biomass fuel. In the illustrated embodiment, the fuel metering disc  40  has two through holes that define two fuel metering receptacles  42  on opposing sides of the fuel metering disc  40 . The blade seal  26  on the guide  22  is sized to engage the top surface  44  of the fuel metering disc  40  across its full diameter. 
     The metering disc  40  is connected to a drive motor  46 , which is coupled to the control system  48 . The control system  48  controls activation and operation of the drive motor  46  so as to control the timing and rate of rotation of the fuel metering disc  40 , thereby controlling the fuel feed rate from the hopper  14  through the fuel metering assembly  28  to the feed auger system (discussed below). 
     In operation, the control system  48  and the drive motor  46  activate rotation of the fuel metering disc  40  relative to the housing  32  and the hopper  14 . The fuel metering disc  40  is rotated in a selected direction, such as clockwise, to a filling position wherein one of the fuel measuring receptacles  42  is partially or fully aligned with the hopper&#39;s outlet aperture. As the fuel metering disc  40  rotates, the blade seal  26  on the guide  22  remains substantially stationary, such that top surface  44  of the metering disc  40  is effectively swept by the blade seal  26 . When the fuel measuring receptacle  42  is aligned below the hopper&#39;s outlet  18 , the fuel measuring receptacle  42  is positioned over a flat portion of the base structure  36  parallel with the metering disc  40  and spaced apart from the fuel receiving opening  38 . Accordingly, the flat portion of the base structure  36  defines a bottom of the metering receptacle  42 . In this position, a selected volume of the biomass fuel drops via gravity from the hopper outlet  18  into the metering receptacle  42 . 
     The drive motor  46 , upon activation, rotates the metering disc  40  relative to the base structure  36  and the hopper  14 , thereby causing the filled metering receptacle  42  to move out of axial alignment with the hopper outlet  18 . As the filled metering receptacle  42  is moved out of alignment with the hopper alignment, the metering disc  40  blocks additional biomass fuel from exiting the hopper  14  until the disc is rotated enough to bring the other metering receptacle  42  into alignment with the hopper outlet  18 . As the metering disc  40  rotates, the filled metering receptacle  42  passes under the blade seal  26 , and the blade seal  26  prevents additional biomass fuel (except for what is in the metering receptacle  42 ) from getting past the blade seal  26 . This insures that only a predetermined amount of fuel (at a predetermined rate) will move away from the hopper outlet  18 , under the blade seal  26  and toward the fuel receiving opening  38  in the base structure  36 . 
     As the drive motor  46  continues to rotate the metering disc  40 , the full metering receptacle  42  will move into an emptying position in alignment with the fuel receiving opening  38  in the base structure  36  (which is on the opposite side of the blade seal  26  relative to the hopper outlet  18 ). In this emptying position, the fuel drops via gravity from the metering receptacle  42  through the fuel receiving opening  38  until the metering receptacle  42  is fully emptied. In the illustrated embodiment, when one metering receptacle  42  is in the filling position, the other metering receptacle  42  is in the emptying position. While the illustrated embodiment has two metering receptacles  42 , other embodiments can have a greater or fewer number of metering receptacles. 
     The base structure  36  is connected to a feed auger assembly  50  positioned and configured to receive the fuel as the fuel empties from the metering receptacle  42  through the fuel receiving opening  38 . The feed auger assembly  50  includes a cylindrical housing  52  that contains a rotatable feed auger  54  coupled to an auger drive motor  56 . The auger drive motor  56  is operatively coupled to the control system  48 . In the illustrated embodiment, the top of the cylindrical housing  52  has an opening aligned with the fuel receiving opening  38  and positioned adjacent to a proximal portion of the feed auger  54 . Accordingly, when the biomass fuel falls from the fuel receiving opening  38 , through the opening and into the cylindrical housing  52 , the rotating auger engages the biomass fuel and pushes the fuel through the housing at the selected rate away from the proximal end  58  of the auger to the distal end  60  of the auger. 
     The feed auger assembly  50  is operatively connected to the fireplace portion so as to feed the fuel as the selected rate into the fireplace portion for combustion. The fireplace portion of the illustrated embodiment has a firebox  70  defined by a plurality of sidewalls  72 , top and bottom walls  74  and  76 , and an openable fireplace door  78 . The fireplace door  78  is movable between an open position, which provides access into the front of the firebox  70 , and a closed position that sealably closes the front of the fire box. In the illustrated embodiment, the fireplace assembly  10  is a direct vent fireplace assembly, although other embodiments can include other configurations. 
     In the illustrated embodiment, the feed auger assembly  50  is sealably connected to the rear wall  80  of the firebox  70  around a firebox fuel aperture  82 . The firebox fuel aperture  82  is in direct communication with the distal end  60  of the feed auger  54 , such that feed auger  54  carries the biomass fuel through the cylindrical housing  52  and pushes the fuel out the distal end  60 , through the firebox fuel aperture  82 , and into the firebox  70 . It is noted that the cylindrical housing  52  and the auger are in direct communication with the firebox  70  and fire that may be burning in the firebox  70 . The construction and arrangement of the fuel metering assembly  28  discussed above, however, is such that there is no direct path between firebox  70  and the hopper  14  because of the offset between the fuel receiving opening  38  and the hopper outlet  18  with the blade seal  26  between them. Even if some of the fuel inadvertently begins to burn in the feed auger assembly  50  adjacent to the fuel metering assembly  28 , the fuel metering assembly&#39;s base structure  36 , the metering disc  40  and the blade seal  26  completely block any fire from ever getting to the hopper-side of the fuel metering assembly  28 . Accordingly, fire can not get to the hopper  14  from the firebox  70 . 
     The firebox  70  contains a burn platform  84  mounted to the rear wall  80  adjacent to the firebox fuel aperture  82  and positioned to receive the biomass fuel from the feed auger assembly  50 . The burn platform  84  is configured so that the feed auger assembly  50  can push the fuel through the firebox feed aperture and onto a rear portion  86  of a support plate  88  of the burn platform  84 . As the auger feed system continues to turn and push more fuel onto the support plate  88 , the new fuel moving onto the rear portion  86  of the support plate  88  pushes the fuel that was already on the plate forwardly toward a forward portion  90  of the support plate  88 . For purposes of explanation, if there was no fire burning in the fire box and the fuel metering assembly  28  and feed auger assembly  50  were allowed to deliver fuel, the fuel on the support plate  88  would continue to be pushed via the entering fuel until the forward-most fuel on the plate would be pushed off a forward edge  92  of a forward portion  90  of the support plate  88  and drop into the ash pan  94 . It is noted that the control system  48  is configured so the fuel metering assembly  28  and the feed auger assembly  50  would not continue to operate when there is not a fire burning or being started in the firebox  70 . 
     The burn platform  84  includes an igniter  96  positioned adjacent to the rear portion  86  of the support plate  88 . The igniter  96  is configured to ignite the biomass fuel on the rear portion  86  of the support plate  88  to start the fire in the firebox  70 . Once the fire has been started, the new fuel entering the firebox  70  through the firebox fuel aperture  82  will be pushed into communication with burning fuel on the support plate  88 . In the illustrated embodiment, the rear portion  86  of the support plate  88  is arranged in an upward sloping angle (as the support plate  88  moves forwardly away from the rear wall  80  of the fire box). This upwardly sloped rear portion  86  of the support plate  88  causes, via gravity, the biomass fuel to stay bunched up on the rear portion  86  of the support plate  88  while some of the fuel is burning and as new fuel is being pushed onto the rear portion  86  of the support plate  88 . This bunching of the fuel help ignite the new fuel and it help the burning fuel to continue burning to be fully engulfed in flames. 
     The support plate  88  transitions from the sloped rear portion  86  to a substantially horizontal forward portion  90 . As the entering fuel continues to push the burning fuel forwardly up the sloped rear portion  86  of the support plate  88 , the burning fuel will be pushed on to the support plate&#39;s horizontal front portion, where the burning fuel can spread out a bit to make a wider burning bed of fuel. The feed rate and burn rate of the fuel can be configured such that, by the time the fuel on the support plate  88  would be pushed off the front edges of the plate, the fuel will have fully burned (i.e., be fully consumed) and transitioned into ash. Accordingly, the entering fuel and the burning fuel will eventually push the consumed fuel as ash off the front edge of the support plate  88 . This ash will drop into the ash pan  94  in the bottom of the firebox  70 . 
     In the illustrated embodiment, the support plate  88  has a plurality of holes  98  in the front and rear portions that allow combustion air to flow through the support plate  88  over and around the fuel to help burning of the fuel. The holes  98  are also sized so that the unburned biomass fuel will not fall through the holes  98  into the ash pan  94 . The holes  98 , however, are sized so that the ash from the consumed fuel can fall through holes  98  into the ash pan  94 , thereby avoiding an undesirable build up of ash along the front edge portion of the support plate  88 . 
     In the illustrated embodiment, the fireplace assembly  10  has a deflector  100  removably mounted in the fire box so as to surround the front and sides of the support plate  88 . The deflector  100  in the illustrated embodiment has a pair of hooks  102  or other engagement members adjacent to the rear portion of the deflector  100 , and the hooks  102  connect to a pair of mounting pins  104  or other mounting structure coupled to the firebox&#39;s rear wall  80 . In other embodiments, the deflector  100  can be mounted directly to the support plate  88  or other structure that holds the deflector  100  adjacent to the support plate  88 . One aspect of the deflector  100  provides a structure that forms a visual block so that a person looking through the door  78  into the firebox  70  can not see the actual burning pieces of fuel. The deflector  100 , however, is sized so that the flames from the burning fuel extend upwardly past the top edge of the deflector  100 , so the person would be able to clearly see the flames from the burning fuel, just not the fuel itself. Accordingly, the deflector  100  acts as a visual deflector. 
     The deflector  100  of the illustrated embodiment has a top edge portion  110  that slopes rearwardly toward the firebox&#39;s rear wall  80 . This rearwardly sloped top edge portion  110  is configured so combustion air passing through the front portion of the support plate  88  will be slightly deflected rearwardly over the burning fuel. The sloped top edge portion  110  is also configured to deflect some of the flames near the front of the support plate  88 , thereby causing the flames to spread out and to flicker/dance more, so as to simulate flames in a conventional wood burning fire. In the illustrated embodiment, the front side of the deflector  100  includes a decorative configuration that provides a very appealing decorative appearance to the user looking into the firebox  70  through the door  78 . 
     The fireplace assembly  10  of the illustrated embodiment has a plurality of safety sensors  112  coupled to the control system  48 . The sensors  112  and the control system  48  are configured to turn off or otherwise temporarily disable the fuel metering assembly  28  and/or the feed auger assembly  50  upon selected events, occurrences, or conditions. For example, the fireplace assembly  10  can includes a pressure sensor coupled to the control system  48 , such that pressure in the fireplace assembly  10 , such as in the firebox  70 , deviates from a selected pressure level or range, the fuel metering assembly  28  can be turn off so fuel delivery to the firebox  70  will stop. The fireplace assembly  10  can include a hopper sensor coupled to the hopper  14  and the control system  48 , such that when the hopper  14  is open otherwise not in its fully closed position, the fuel metering assembly  28  is turned off so fuel delivery to the firebox  70  will stop. Other sensors  112 , including proximity sensors, temperature-based sensors, and other sensors can be used to help control operation of the fireplace assembly  10 . 
     The control system  48  of at least one embodiment provides a plurality of operation configurations or programs that operatively control the fuel metering assembly  28  and/or the feed auger assembly  50 , such as to control the feed rate of the fuel from the hopper  14  into the burner area. For example, the control system  48  can have different operation programs based upon the type of biomass fuel to be burned in the fireplace assembly  10 . One program can be for wood pellets so as to provide the appropriate feed rate and burn rate for wood pellets. Another program can be for wood chips, another program can be for corn-based fuel, and another program can be for fruit pits, such as peach or nectarine pits. Other programs can be used for other selected solid fuels (including biomass or non-biomass fuels). The control system  48  can also have programs based upon the desired burn rate and the BTU output for the fireplace assembly  10 . The control system  48  can have programs that are based upon a combination of the types of fuel and the desired BTU output. Yet other programs can be provided that are based upon selected time durations for operation of the fireplace assembly  10 . Other embodiments can have control systems with other operation programs for a desired type of operation of the fireplace assembly  10 . 
     From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the invention. Additionally, aspects of the invention described in the context of particular embodiments or examples may be combined or eliminated in other embodiments. Although advantages associated with certain embodiments of the invention have been described in the context of those embodiments, other embodiments may also exhibit such advantages. Additionally, not all embodiments need necessarily exhibit such advantages to fall within the scope of the invention. Accordingly, the invention is not limited except as by the appended claims.

Technology Category: f