Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24B—DOMESTIC STOVES OR RANGES FOR SOLID FUELS; IMPLEMENTS FOR USE IN CONNECTION WITH STOVES OR RANGES
  • F24B13/00—Details solely applicable to stoves or ranges burning solid fuels 
  • F24B13/04—Arrangements for feeding solid fuel, e.g. hoppers 
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23B—METHODS OR APPARATUS FOR COMBUSTION USING ONLY SOLID FUEL
  • F23B50/00—Combustion apparatus in which the fuel is fed into or through the combustion zone by gravity, e.g. from a fuel storage situated above the combustion zone
  • F23B50/12—Combustion apparatus in which the fuel is fed into or through the combustion zone by gravity, e.g. from a fuel storage situated above the combustion zone the fuel being fed to the combustion zone by free fall or by sliding along inclined surfaces, e.g. from a conveyor terminating above the fuel bed

Definitions

• the present invention is a fuel feed system for use in pellet fires.
• Pellet fires are becoming more popular; they burn compressed pellets of combustible material, normally wood, but corn, grain and other materials are used.
• the pellets are a uniform size range and composition so their combustion is more predictable than natural wood or coal.
• Pellet fires automatically feed the fuel into the fire box from a storage hopper. Pellet fires are classified by their method of feeding fuel into the burn pot, top feed or bottom feed.
• a horizontal auger that normally lies in the base of the burn pot, for at least part of its length, feeds the pellets from the hopper through the burn pot and discharges the ash out the other end. It can be difficult to prevent the fire burning back into the hopper full of fuel if a power failure occurs.
• the auger is exposed to the full heat of the fire and the abrasive and/or corrosive ash and combustion products.
• a top feed pellet fire an inclined auger lifts the pellets from the base of the hopper and discharges them above the burn pot. The pellets then gravity feed into the burn pot, often falling onto an inclined plate first.
• This feed is from a single tube or chute which forms a single pile of pellets in the burn pot, which some find creates a less aesthetically appealing flame than the bottom feed.
• the gravity feed section minimises the chance of any burn back into the hopper. It is preferably an object of the present invention to provide a fuel feed system for a pellet fire that ameliorates one or more of the limitations of existing systems, or provides the consumer with a useful choice.
• the present invention provides a fuel feed system for a pellet fire which includes conveying means within a casing, said casing including a plurality of inlet means distributed lengthwise along the casing and a plurality of outlet means distributed lengthwise along the casing, such that each inlet means is horizontally offset from the adjacent outlet means and wherein said conveying means is configured to move compressed fuel pellets from an inlet means to an adjacent outlet means; such that in use said fuel feed system is configured to form a plurality of overlapping piles of compressed fuel pellets in a burn pot of the pellet fire.
• the longitudinal axis of the casing and the burn pot are approximately parallel.
• said inlet means and/or outlet means are apertures in the casing.
• the conveying means is one or more concentrically aligned augers.
• the conveying means is a single auger.
• the casing is not a single piece of material.
• the casing is formed by parts of the pellet fire or fuel feed system alone or in combination with additional separate components.
• the fuel feed system includes a plurality of delivery ducts and/or channels such that each outlet means forms one end of an associated delivery duct or channel, such that at an opposite end of each said delivery duct or channel there is a delivery outlet that is configured to deliver the compressed fuel pellets, directly or indirectly, into the burn pot.
• the fuel feed system includes a distribution section which lies between the delivery outlets and the burn pot.
• the distribution section is an angled plate that vertically and/or horizontally separates the delivery outlets and the burn pot.
• the fuel feed system does not include delivery ducts and/or channels it includes a primary distribution section which lies between the outlet means and the burn pot.
• the primary distribution section is an angled plate that vertically and/or horizontally separates the outlet means and the burn pot.
• the invention also includes a pellet fire incorporating the fuel feed system.
• the pellet fire includes a hopper configured to store compressed fuel pellets such that an outlet of the hopper is coterminous with the fuel feed system.
• the casing lies essentially horizontally across the outlet of the hopper.
• the fuel feed system includes a plurality of casings, either separated or coterminous, each with at least one conveying means.
• Figure 1 is a cutaway pictorial view of a pellet fire showing the fuel feed system
• Figure 2 is a pictorial view of a hopper with a fuel feed system and fire box removed from the pellet fire;
• Figure 3 is a plan view of the hopper with feed system and fire box removed from the pellet fire, with no fuel in the hopper or burn pot;
• Figure 4 is a cross sectional plan view through the hopper and fuel feed system in the direction of arrows A-A., with no fuel in the burn pot;
• Figure 5 is a is a plan view of the hopper with feed system and fire box removed from the pellet fire, with fuel pellets in the hopper and interlinking piles of pellets in the burn pot
• FIG. 1 a cutaway view of a pellet fire (1 ) including a first sub-assembly (2) is shown.
• Said first sub assembly (2) includes a hopper (3), fuel feed system (4) and burn pot (5), such that the hopper (3) is a storage container for compressed fuel pellets of a known type.
• the hopper (3) is connected to the fuel feed system (4), which in turn is connected to the burn pot (5).
• the burn pot (5) is of a known type that includes a channel (6) with a perforated base (7) which, when the pellet fire (1 ) is in use, acts as a grate. Other surfaces of the channel (6) or burn pot (5) may also be perforated but this is optional and not shown in the drawings.
• Figures 2 to 5 the first sub-assembly (2) is shown removed from the pellet fire (1 ) for clarity.
• Figures 2 to 4 show the first sub-assembly (2) without compressed fuel pellets.
• FIG. 10 where figure 4 is a cross sectional view in the direction of arrows A-A shown in figure 2, the fuel feed system (4) including a second subassembly (10) is shown.
• the second sub-assembly (10) includes a conveying means (1 1 ), a plurality of inlet means (12) and a plurality of outlet means (13).
• Each inlet means (12) is separated from the adjacent inlet means (12) by first shield means (14), and each outlet means (13) is separated from the adjacent outlet means (13) by second shield means (15).
• the conveying means (1 1 ) is an auger of known type which lies essentially horizontally (though in some embodiments may be angled) across the base of the hopper (3).
• the first and second shield means (14, 15) form a casing (16) in which the conveying means (1 1 ) is located, the inlet and outlet means (12, 13) are apertures in this casing (16).
• Each inlet means (12) is horizontally offset from the nearest outlet means (13) along the length of the casing (16).
• the first sub-assembly (2) further includes a plurality of delivery means (20) and delivery outlets (21 ), and a distribution section (22).
• Each delivery means (20) is a duct which has an outlet means (13) as one end and a delivery outlet (21 ) as the opposite end.
• Each delivery means (20) is angled such that the delivery outlet (21 ) is vertically separated from the associated outlet means (13).
• the term 'duct' is intended to include hollow prisms with any cross sectional shape, even if the cross sectional shape changes from one end to the other.
• Each delivery outlet (21 ) lies above the distribution section (22) which is connected to the burn pot (5).
• the distribution section (22) is an angled plate extending the length of the channel (6). Referring to figure 5, the first sub-assembly (2) containing compressed fuel pellets is shown.
• the fuel feed system (4) in use, creates a plurality of overlapping pellet piles (30), such that in use these overlapping piles form a wide flame front in the burn pot (5).
• the compressed fuel pellets in the hopper (3) fall, or are pulled through, an inlet means (12).
• the conveying means (1 1 ) then moves these compressed fuel pellets to a horizontally offset adjacent outlet means (13).
• the compressed fuel pellets then move through the delivery means (20) associated with that outlet means (13) and out of the associated delivery outlet (21 ).
• the compressed fuel pellets then fall onto the distribution section (22) and are gravity fed into the channel (6).
• Each delivery outlet (21 ) directs compressed fuel pellets onto a separated, but overlapping pellet pile (30) for combustion.
• each inlet means (12) is horizontally offset from each adjacent outlet means (13), the mass/volume of compressed fuel pellets through the fuel feed system (4) can be controlled.
• the compressed fuel pellets cannot fall directly from an inlet means (12) into an outlet means (13), they must be physically moved from one to the other by the conveying means (1 1 ).
• This horizontal separation of adjacent inlet and outlet means (12,13) prevents the compressed fuel pellets from directly feeding from the hopper (3) to the burn pot (5). If the conveying means (1 1 ) is stopped then the compressed fuel pellet flow is essentially stopped at the same time.
• the fuel feed system (4) is not directly connected to the burn pot (5).
• the fuel pellets fall from the fuel feed system (4) into the burn pot (5).
• the distribution section (22) is not present, so that in use the compressed fuel pellets fall directly from each delivery outlet (21 ) into the burn pot (5).
• the second sub-assembly (10) is not at the base of the hopper (3).
• the conveying means (1 1 ) is a plurality of augers each able to be separately driven.
• augers which may or may not be concentrically aligned. For example (not shown) they may be parallel with horizontal or vertical separation.
• each of these additional casings is similar to the casing (16) in that they include additional inlet and/or outlet means that are horizontally separated, and house one or more additional conveying means.
• additional conveying means there may be two parallel augers within a single casing, two additional conveying means in two separated casings each configured to, either separately or in combination, create a plurality of overlapping pellet piles (30).
• the conveying means (1 1 ) is not located in the casing (16) and the casing (16) is hollow.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Filling Or Emptying Of Bunkers, Hoppers, And Tanks (AREA)
• Solid-Fuel Combustion (AREA)
• Fluidized-Bed Combustion And Resonant Combustion (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

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Citations (3)

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• 2010
  • 2010-02-10 NZ NZ578968A patent/NZ578968A/en unknown
• 2011
  • 2011-01-31 EP EP11741961.4A patent/EP2534423B1/de not_active Not-in-force
  • 2011-01-31 WO PCT/IB2011/050405 patent/WO2011098932A1/en active Application Filing
  • 2011-01-31 AU AU2011213993A patent/AU2011213993B2/en not_active Ceased
  • 2011-01-31 JP JP2012552495A patent/JP5780436B2/ja not_active Expired - Fee Related
  • 2011-01-31 HU HUE11741961A patent/HUE046137T2/hu unknown

Patent Citations (3)

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