Combustible fuel burning stove with pellet adapter

Abstract

A stove is provided that includes a combustion chamber, a fuel grate disposed within the combustion chamber, and a pellet adapter removably positionable on the fuel grate. The fuel grate includes a plurality of first vent holes. The pellet adapter includes a plurality of second vent holes sized and shaped to prevent the passage of fuel pellets. The pellet adapter also includes a raised outer rim and a central protrusion having a height greater than the height of the raised outer rim.

Description

[Technical Field]

[0001] The subject matter described herein relates to a combustible fuel burning stove, such as a fire pit, with an adapter for burning biomass pellets. [Background technology]

[0002] Portable wood stoves, such as fire pits, are used in camping situations to use twigs and sticks as fuel for heating and cooking. Similarly, larger portable fire pits are used in residential backyards for recreational purposes, to provide outdoor heating, and for limited cooking such as roasting marshmallows.

[0003] However, portable wood stoves, including portable fire pits, are typically fueled by a pile of twigs or logs (e.g., firewood), which are supported by a fuel grate. The fuel grate includes sufficient structural features to support the sometimes-heavy fuel load at operating temperatures of about 700°F (371°C) to about 1350°F (732°C). Furthermore, fuel grates are generally designed to resist distortion or deformation when thermally cycled between these high operating temperatures and much cooler ambient temperatures of about 100°F (38°C) to -40°F (-40°C). Meanwhile, fuel grates typically have large and / or numerous vents to provide sufficient airflow for combustion.

[0004] In some cases, wood pellets are considered to have advantages over firewood. Pellets can be easily stored in bags or barrels, have a high energy density, and burn slower than firewood, providing more uniform heat, light, and atmosphere from a stove over a longer period of time. However, the above-described design features of fuel grates can be problematic for users who want to burn smaller fuel sources, such as wood pellets, because such small fuel sources tend to fall through the fuel grate vents. Furthermore, wood pellets tend to be stacked more densely than twigs or logs, which can reduce the space for airflow between the pellets, causing the pile of wood pellets to burn from top to bottom rather than bottom to top. Therefore, flat or dome-shaped fuel grates may not promote uniform, smokeless combustion of wood pellets and other small fuels, such as paper pellets and wood chips.

[0005] It can therefore be appreciated that such commonly used fuel grates have many drawbacks, including one or more of large vents, smoke generation, and other issues. Accordingly, there exists a long-felt need for fire pit and portable wood stove constructions that address the above and other concerns.

[0006] The information contained in the Background section of this specification, including the references cited herein and their descriptions or discussion, is included for technical reference purposes only and should not be considered as subject matter limiting the scope of the present disclosure. Summary of the Invention [Means for solving the problem]

[0007] A pellet adapter for a wood-burning stove is disclosed. The pellet adapter includes novel structural features that allow the pellet adapter to be mounted on a fuel grate within the stove body. The pellet adapter includes features that prevent wood pellets from falling through the fuel grate vent and provide for uniform pellet distribution and combustion. The pellet adapter is particularly useful in wood-burning fire pits and camp stoves, but is not limited to such applications, allowing for the burning of pellet fuel instead.

[0008] One general embodiment may include a combustion fire pit stove including a combustion chamber, a fuel grate disposed within the combustion chamber, the fuel grate including a plurality of first vent holes, and a pellet adapter removably positionable within the combustion chamber on the fuel grate, the pellet adapter being a pellet tray including a plurality of second vent holes sized and shaped to prevent the passage of fuel pellets therethrough, the pellet adapter including a raised outer rim and a central protrusion having a height greater than the height of the raised outer rim.

[0009] Embodiments may include one or more of the following features. In some embodiments, the pellet adapter further includes a plurality of recesses. In some embodiments, the pellet tray includes a handle that can be gripped by a user. In some embodiments, the recesses include feet that contact the fuel grate when the pellet adapter is placed on the fuel grate in the combustion chamber. In some embodiments, a lower end of the raised outer rim contacts the fuel grate when the pellet adapter is placed on the fuel grate in the combustion chamber. In some embodiments, the central protrusion includes a lower portion fixedly attached to the pellet tray and an upper portion removably attached to the lower portion. In some embodiments, the central protrusion includes a plurality of third vent holes sized and shaped to prevent the passage of the fuel pellets. In some embodiments, the central protrusion includes a frustoconical shape. In some embodiments, the pellet tray includes a frustoconical shape. In some embodiments, the raised outer rim includes a plurality of fourth vent holes sized and shaped to prevent the passage of the fuel pellets. In some embodiments, when the pellet adapter is placed on the fuel grate in the combustion chamber, a gap exists between the raised outer rim and an inner wall of the combustion chamber.

[0010] One general embodiment includes a pellet adapter for adapting a wood-burning stove to a pellet-burning stove, the pellet adapter including a pellet tray including a plurality of vent holes sized and shaped to prevent the passage of fuel pellets, a raised outer rim, and a central protrusion having a height greater than the height of the raised outer rim, the pellet adapter being removably positionable on a stove's fuel grate within the stove's combustion chamber.

[0011] Embodiments may include one or more of the following features. In some embodiments, the pellet adapter further includes a plurality of recesses formed in the pellet tray. In some embodiments, the recesses include feet that contact the fuel grate when the pellet adapter is placed on the fuel grate in the combustion chamber. In some embodiments, the central protrusion includes a lower portion fixedly attached to the pellet tray and an upper portion removably attached to the lower portion. In some embodiments, at least one of the central protrusion or the raised outer rim includes a plurality of third vent holes sized and shaped to prevent passage of the fuel pellets. In some embodiments, the central protrusion includes a frustoconical shape. In some embodiments, the pellet tray includes a frustoconical shape. In some embodiments, when the pellet adapter is placed on the fuel grate in the combustion chamber, a gap exists between the raised outer rim and an inner wall of the combustion chamber, and a lower end of the raised outer rim contacts the fuel grate.

[0012] One general aspect includes a stove that burns pelletized fuel to produce heat, the stove including: an inner wall having a lower portion and an upper portion; an outer wall having a lower portion and an upper portion; an air-filled space between the inner and outer walls; a chimney formed by the inner wall; a combustion region located within the chimney; at least one vent hole in the upper portion of the inner wall; at least one vent hole in the lower portion of the outer wall; a fuel grate located within the combustion region and including a plurality of first vent holes; and a pellet adapter removably positionable on the fuel grate within the combustion region, the pellet adapter including a pellet tray including a plurality of second vent holes sized and shaped to block passage of the pelletized fuel; a raised outer rim; and a central protrusion having a height greater than the height of the raised outer rim.

[0013] In yet another embodiment, the present disclosure relates to a pellet adapter for adapting a log or stick burning stove to a pellet-burning stove. The log or stick burning stove may include a combustion chamber with a fuel grate therein. The fuel grate may have holes configured to allow air or ash to pass therethrough, and the holes may have a first width that does not inhibit or prevent the passage of fuel pellets. The pellet adapter may include a pellet tray having a plurality of vent holes with a second width smaller than the first width, the second width sized to inhibit or prevent the passage of the fuel pellets; and a handle on the pellet tray that can be grasped by a user to introduce or remove the pellet tray from the combustion chamber to adapt the stove to a pellet-burning stove.

[0014] In some embodiments, the pellet adapter may include a raised outer rim having a first height around the pellet tray. In some embodiments, the pellet adapter may include a central protrusion extending from the pellet tray at a second height greater than the first height. In some embodiments, the handle may be formed as at least one of an opening in the central protrusion or a graspable handle extending above the pellet tray. In some embodiments, the pellet adapter further includes a plurality of recesses formed in the pellet tray, the recesses forming legs that offset the pellet tray from the fuel grid.

[0015] In yet another embodiment, the present disclosure relates to a method of adapting a log or branch burning stove to a pellet-burning stove, the log or branch burning stove including a combustion chamber with the fuel grate therein. The fuel grate may have holes configured to allow air or ash to pass therethrough, and the holes may have a first width that does not inhibit or prevent the passage of fuel pellets. The method may include gripping a pellet adapter with a handle, the pellet adapter having a pellet tray with a plurality of vent holes having a second width smaller than the first width, the second width sized to inhibit or prevent the passage of the fuel pellets; introducing the pellet adapter into an upper opening of the combustion chamber of the log or branch burning stove; and loading fuel pellets onto the pellet tray for combustion.

[0016] In some aspects of the method, the step of introducing the pellet adapter into the upper opening of the combustion chamber includes positioning the pellet adapter on the fuel grate, and the pellet adapter may be offset from the fuel grate to allow air to flow between the fuel grate and the pellet adapter.

[0017] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter. A more extensive presentation of the features, details, utilities, and advantages of the fuel grid defined in the claims is provided below in the description of various embodiments of the present disclosure and illustrated in the accompanying drawings. [Brief explanation of the drawings]

[0018] Exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. [Figure 1]FIG. 1 is a perspective exploded view of an exemplary combustion stove, such as a wood fire pit, in accordance with at least one embodiment of the present disclosure. [Figure 2] FIG. 2 is a perspective cross-sectional view of an exemplary combustion stove, such as a wood fire pit, including a pellet adapter on a fuel grate in accordance with at least one embodiment of the present disclosure. [Figure 3] FIG. 3 is a top perspective view of a pellet adapter removably mounted within a wood stove in accordance with at least one embodiment of the present disclosure. [Figure 4] FIG. 4 is an exemplary diagram of a pellet adapter and fuel grate for a wood stove according to at least one embodiment of the present disclosure. [Figure 5] FIG. 5 is a front perspective exploded view of an exemplary pellet adapter for a wood stove according to at least one embodiment of the present disclosure. [Figure 6] FIG. 6 is a perspective exploded view of an exemplary pellet adapter according to at least one embodiment of the present disclosure. [Figure 7] FIG. 7 is a front perspective view of an exemplary pellet adapter for a wood stove according to at least one embodiment of the present disclosure. [Figure 8] FIG. 8 is a perspective exploded view of an exemplary tabletop combustion stove, such as a wood fire pit, in accordance with at least one embodiment of the present disclosure. [Figure 9] FIG. 9 is a perspective cross-sectional view of an exemplary tabletop combustion stove, such as a wood stove, including a pellet adapter on a fuel grate in accordance with at least one embodiment of the present disclosure. [Figure 10] FIG. 10 is a front perspective view of the exemplary pellet adapter of FIG. 7 in accordance with at least one embodiment of the present disclosure. [Figure 11] FIG. 11 is a front perspective view of an exemplary pellet adapter for a wood stove according to at least one embodiment of the present disclosure. [Figure 12] FIG. 12 is a front perspective view of an exemplary pellet adapter for a wood stove according to at least one embodiment of the present disclosure. [Figure 13] FIG. 13 is a front perspective view of an exemplary pellet adapter for a wood stove according to at least one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0019] A pellet adapter for a wood-burning stove is provided. The pellet adapter includes novel structural features that allow it to be mounted on a fuel grate permanently or removably attached within the stove body. The pellet adapter includes features that prevent pelletized biomass fuel (e.g., wood pellets, paper pellets, wood chips, etc.) from falling through the fuel grate vent and features that provide even distribution of fuel pellets and top-to-bottom combustion. The pellet adapter of the present disclosure also includes airflow features that lead to complete combustion of the fuel, thereby generating more heat and substantially reducing smoke. This design can be easily manufactured as a single piece (e.g., stamped from a metal sheet blank) or may be assembled from two stamped pieces (allowing the pellet adapter to be shipped in a compact container). These configurations allow the pellet adapter to be placed on the fuel grate without significantly increasing weight or compromising the wood-burning stove's airflow, while maintaining the stove's portability and / or storage capacity.

[0020] Thus, for friends gathered around a stove or fire pit (at a campsite, picnic table, tailgate party, backyard, or elsewhere), the stove or fire pit can be easily converted from burning wood to burning biomass pellets or other pelletized fuels with the addition of a pellet adapter. Pelleted fuels are easily storable and transportable (e.g., in bags or barrels) and have a high energy density. Furthermore, the stove and pellet adapter features provide favorable airflow for long-lasting heat, light, and atmosphere with very little smoke production, making for a repeatable and enjoyable outdoor experience. Stoves with pellet adapters are also convenient for emergency use in situations where other heat or light sources are unavailable.

[0021] The pellet adapter includes a breathable pellet tray, an outer retention rim, and a central protrusion. Together, these features enable optimal placement of biomass pellets for relatively smokeless top-down combustion. The pellet adapter also includes a plurality of embossed or indented features that function as handles and as feet that position the pellet adapter in contact with the fuel grid while maintaining an air gap between the pellet adapter and the fuel grid.

[0022] For the purposes of promoting an understanding of the principles of the present disclosure, reference will be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will be understood, however, that no limitation of the scope of the present disclosure is intended. All changes and further modifications to the described apparatus, systems, and methods, and further applications of the principles of the present disclosure, as would normally occur to one skilled in the art to which the present disclosure pertains, are fully contemplated and are within the scope of the present disclosure. In particular, it is fully contemplated that features, components, and / or steps described with respect to one embodiment may be combined with features, components, and / or steps described with respect to other embodiments of the present disclosure. However, for the sake of brevity, numerous iterations of these combinations have not been individually described.

[0023] These descriptions are provided for illustrative purposes only and should not be considered as limiting the scope of the pellet adapter. Certain features may be added, deleted, or modified without departing from the spirit of the claimed subject matter.

[0024] 1 is an exploded view showing, in a partially disassembled state, some major components of an exemplary combustion stove system 80, also referred to as a fire pit system. The combustion stove system 80 shown in this figure includes a combustion stove, shown as a fire pit 150, a pellet adapter 200 that removably fits within a combustion chamber 190 of the fire pit 150, and a flame ring 115 that may be positioned on top of the fire pit 150.

[0025] FIG. 2 is a perspective cross-sectional view of an exemplary combustion stove system 80, in this example a wood-burning fire pit system, shown with a pellet adapter 200 positioned within a combustion chamber 190. Referring to both FIGS. 1 and 2, a fire pit 150 may include a fire grate or fuel grate 100 positioned within the fire pit 150 to support the weight of fuel (e.g., wood logs, sticks, and other fuels) while allowing airflow through the fuel grate 100 and fire pit 150 to promote combustion of the fuel. In the embodiment shown in FIG. 1, the fuel grate is formed of a metal plate with openings for air and ash to pass through. The fuel grate 100 is strong and rigid to withstand the weight of firewood or other fuel at both ambient and operating temperatures and, due at least in part to its slightly domed shape, can withstand substantial distortion or other substantial deformation even under repeated exposure to the heat of combustion over long periods of time. The fuel grate 100 may also be lighter and have greater airflow than other fuel grates of comparable size.

[0026] 2, the fire pit 150 includes an upper portion 152, a lower portion 154, and a middle portion 156. The fire pit 150 further includes an inner wall or inner body 110, an outer wall or outer body 120, a connecting ring 125 located at the upper portion 152 of the fire pit 150 and attached to or integrally formed with the inner body 110 and / or the outer body 120, and a combustion chamber 190 defined by the inner body 110 and within which the fuel grate 100 is disposed. The fire pit 150 further includes a flame ring 115 that helps direct airflow toward the central axis 270 when the fire pit 150 is in use. The shape and size of the flame ring can promote cleaner combustion by directing air in the manner described herein. The fire pit 150 further includes a plurality of exterior vents 122 located at the bottom 154 of the outer body 120 and a plurality of interior vents 124 located at the top 152 of the inner body 110. At a middle portion 156 of the fire pit 150, the inner body 110 terminates in a radially inwardly protruding edge that may support an ash pan and fuel grate 100.

[0027] The fire pit 150 further includes a base plate 170 attached to the outer body 120, a reinforcing tray 175 supported by a stand projecting upwardly from the base plate or suspended from the inner body 110, and a catch tray or ash pan 180 which may be supported by a stand projecting upwardly from the reinforcing tray 175 or otherwise suspended from the inner body 110, such that the reinforcing tray 175 is separated from the outer body 120 by a gap 176, the ash pan 180 is separated from the outer body 120 by a gap 178, and the inner body is separated from the outer body by a gap 179. In one example, gaps 176 and 179 are both approximately 50 mm and gap 178 is approximately 100 mm, although other gaps may be used with the disclosed beneficial effects.

[0028] As shown in FIG. 2, the reinforcement tray 175 includes a vent 177, which in the illustrated example is centrally located directly below the ash pan 180.

[0029] Cavity 190 is in fluid communication with void 179 via internal vent 124. Cavity 190 is in fluid communication with voids 178 and 176 via fuel grate 100. Voids 176 and 178 are in fluid communication with ambient air via external vent 122, such that ambient air can be drawn in through external vent 122, heated by the combustion of the fuel, and exhausted through cavity 190 and internal vent 124 to favorably combust the fuel. In some examples, the fire pit may be similar in some or all respects to the fire pit described in U.S. Patent Application No. 17 / 169,269, filed February 5, 2021, and incorporated herein by reference in its entirety.

[0030] In one example, the fuel grate 100 and other components of the fire pit 150 are both made from stainless steel plate having a thickness ranging from about 0.5 mm to about 2.5 mm. Some examples of the fuel grate 100 and other components of the fire pit 150 are formed with a thickness of 1.0 mm to 2.0 mm, with one example being stainless steel having a thickness of about 1.5 mm. Both thicker and thinner materials are contemplated. In one example, the fuel grate 100 weighs about 48 pounds (21.8 kg), although weights between about 9 ounces and about 88 pounds can be provided. In one example, during normal operation, the fuel grate 100 supports a nominal weight of 100 pounds (45.4 kg) (although a nominal capacity of between about 5 pounds and about 190 pounds may be provided) while the fuel grate 100, or a portion thereof, is heated by burning fuel to between about 700°F (371°C) and about 1350°F (732°C) for a period of 1 to 12 hours and is at an ambient temperature of −40°F (−40°C). In one example, during several years of normal operation, cycling (e.g., 100 cycles) between ambient and operating temperatures, the fuel grate 100 exhibits little or no distortion that may adversely affect its aesthetic appearance, its performance, or its suitability within the fire pit 150.

[0031] The primary load carried by the fuel lattice 100 is exerted downward, parallel to the axis 270, by the weight of the fuel stacked on the fuel lattice 100, which is supported directly or indirectly by the stiffening tray 175.

[0032] When a fire is ignited, a vacuum is created at the bottom of the cavity or combustion chamber 190 due to the rising hot air and lack of oxygen caused by the combustion process. This vacuum draws oxygen through the vents 122 in the bottom of the outer wall or outer body 120 and directs it upward into the cavity or combustion chamber 190. More specifically, cooler outside air flows inward through the vents 122 and may then bifurcate into two paths: an upward flow toward the vents 124 and a laterally inward flow toward the cavity or combustion chamber 190. The laterally inward flowing air flows between the reinforcing tray 175 and the base plate 170, through one or more vents 177 in the reinforcing tray 175, around the bottom of the ash pan 180, and upward through the fuel grate 100, entering the cavity or combustion chamber 190 to support the direct (primary) combustion of the fuel. In the illustrated example in which the pellet adapter 200 is positioned for use, air flows not only through the fuel grate but also through the pellet adapter into the combustion chamber 190. The configuration of the pellet adapter 200, including the vent openings in the pellet adapter 200, is described further below. The configuration shown in FIGS. 1 and 2 allows for secondary combustion of unburned volatile organic compounds (VOCs) released from the fuel during combustion. This occurs because additional oxygen travels vertically upward from the vent holes 122 through the gap 179 between the outer wall or outer body 120 and the inner wall or inner body 110, where it is preheated by the temperature of the inner body 110. The oxygen then flows back into the cavity or combustion chamber 190 through the top vent holes 124, resulting in further combustion of the VOCs in a column of heat and flame that rises within the cavity or combustion chamber 190. The flame ring 115 helps direct oxygen into the column, thereby generating additional heat and combustion of the VOCs. Such secondary combustion not only increases the heat and light output of the fire pit 150, but also reduces smoke production by ensuring more complete combustion of the fuel.

[0033] FIG. 2 illustrates a pellet adapter 200 positioned in an operational position above a fuel grate 100, in accordance with at least one embodiment of the present disclosure. The pellet adapter 200 is removably positioned over the fuel grate 100 within the cavity or combustion chamber 190, such that a gap 220 is maintained between the fuel grate 100 and the pellet adapter 200, and such that a portion or feature of the pellet adapter 200 contacts and is supported by the fuel grate 100. The pellet adapter 200 is also shaped and sized such that a raised outer rim or retaining rim 230 of the pellet adapter 200 leaves a gap 210 between the outer rim or retaining rim 230 and the inner wall or inner body 110. In some embodiments, the pellet adapter 200 can be sized small enough so that the gap 210 inhibits or prevents pellets from falling between the retaining rim 230 and the inner wall or inner body 110. Thus, in some examples, the gap 210 is in the range of approximately 1-8 mm. However, other gap sizes are contemplated. The gap 210 may also allow for air flow between the pellet adapter 200 and the interior wall or inner body 110, and may be sized to accommodate a user's hand or gripping device to facilitate grasping the pellet adapter 200 as it is lowered into or raised from the cavity or combustion chamber 190. Thus, the gap 210 may also provide clearance to allow the pellet adapter 200 to be easily lifted, removed, and introduced into the combustion chamber 190.

[0034] The addition of the pellet adapter 200 to the fire pit 150 and fuel grate 100 allows the fire pit 150 to burn biomass pellets instead of firewood, providing the above-mentioned advantages of a storable, energy-dense fuel that burns more evenly over a longer period than firewood, thus allowing the fire pit 150 to provide the desired heat, light, and atmosphere for an extended period of time while maintaining the advantageous airflow described in Figure 2. Although described herein as wood pellets, it will be apparent that any biomass pellets may be used.

[0035] Figures 3-5 show the pellet adapter in more detail. Figure 3 shows the pellet adapter 200 removably mounted within the fire pit 150, Figure 4 shows the pellet adapter 200 positioned on a fuel grate onto which it may be placed during use, and Figure 5 shows an example of the pellet adapter 200 in an exploded state according to at least one embodiment of the present disclosure.

[0036] 3-5, the pellet adapter 200 includes a raised outer rim or pellet-retaining rim 230 and a pellet tray 320 including a plurality of ventilation holes 330. The outer rim or pellet-retaining rim 230 may, for example, be part of the pellet tray 320 or may be integrally formed with the pellet tray 320 and may advantageously serve to prevent wood pellets or other fuel from rolling off the sides of the pellet tray 320. The pellet tray 320 also includes a plurality of ventilation holes 330 sized and shaped to prevent biomass pellets or similar solid fuels from easily falling through the holes. These holes 330 may be smaller than the holes in the fuel grate 100, for example (see FIG. 1). In some examples, the ventilation holes 330 are sized to have a width in the range of approximately 1-5.5 mm, thereby preventing pellets 6 mm or wider from passing through. In some embodiments, the ventilation holes 330 are sized to have a width in the range of approximately 1-7.5 mm, thereby preventing pellets 8 mm or wider from passing through. Other sizes are contemplated to accommodate different sized pellets. In contrast, the fuel grid vents may be sized greater than 8 mm and allow the passage of pellets 8 mm wide or less.

[0037] In order for the pellet adapter 200 to provide airflow similar to that of the fuel grid 100, the vent holes 330 in the pellet tray 320 of the pellet adapter 200 may be more numerous than the vent holes in the fuel grid 100, such that the total area of ​​the holes 330 is comparable to the total area of ​​the holes in the fuel grid 100.

[0038] In the example shown in FIGS. 3-5 , the pellet adapter 200 also includes a plurality of recesses or legs 340 (also referred to as feet). In some embodiments, these recesses or legs 340 extend below the main surface of the pellet tray 320 and cooperate to offset the bottom surface of the pellet tray 320 from the fuel grate 100. This provides an air passage between the pellet adapter 200 and the fuel grate 100, allowing air to flow through all of the vent holes 330, not just the side edges of the pellet adapter 200, and through the fuel grate, enabling stable combustion. In this embodiment, the legs 340 are recesses formed in the pellet tray 320; however, in other embodiments, the legs 340 may be attached to the pellet tray or otherwise positioned to offset the pellet tray 320 from the fuel grate 100.

[0039] The exemplary pellet adapter 200 described herein also includes a handle 302 that can be grasped by a user (e.g., to place the pellet adapter 200 in the fire pit 150 or to remove the pellet adapter 200 from the fire pit 150). In this embodiment, the handle 302 is centrally located and formed with two openings into which an implement or a user's fingers can be inserted to grasp the pellet adapter. However, other handles are contemplated. The handle 302 is positioned at a height above the pellet tray 320, thereby allowing the handle to be grasped even when pellets are in the pellet tray 320.

[0040] In the illustrated example, the pellet adapter 200 also includes a central protrusion 345 (e.g., a truncated cone or the like) that prevents wood pellets from stacking in or near the center of the pellet tray 320. This facilitates stacking wood pellets in a ring shape around the periphery of the pellet tray 320, which is advantageous for slow, uniform, and relatively smokeless combustion. The central protrusion 345 may include, for example, a bottom portion 350 that may be part of or integrally formed with the pellet tray 320, and a top portion 360 that is removably attached to the bottom portion 350. However, in other embodiments, the central protrusion 345 may be a single piece that is removably attached to the pellet tray 320, or may be a single piece that is part of or integrally formed with the pellet tray 320. The height of the upper portion 360 is generally greater than the height of the raised outer rim 230, such that the overall height of the pellet adapter 200 is defined by the central protrusion 345 rather than the outer rim 230. In the illustrated example, the handle 302 is located at the apex of the protrusion 345.

[0041] 3-5, the central protrusion 345 generally has a frusto-conical shape, with a wider base and a narrower top. The upper portion 360 includes a central hub 440, which may be, for example, a part of the upper portion 360 or may be integrally formed with the upper portion 360. Additionally, the pellet tray 320 is sloped and generally frusto-conical in shape, though shorter, flatter, or shallower than the frusto-conical shape of the central protrusion 345. This configuration, for example, promotes desirable fuel pellet distribution; as pellets pour into the pellet tray 320 under the influence of gravity, the pile of pellets may naturally be deeper near the outer rim 230 of the pellet adapter 200 and shallower near the central protrusion 345, tending not to follow the slope of the central protrusion. The resulting distribution 450 may, for example, be generally wedge-shaped in cross section and generally toroidal when viewed from above, which may promote greater combustion near the outer retaining rim 230 and less combustion near the central protrusion 345. It is understood that other tapered shapes, including dome or pyramidal shapes, may alternatively or additionally be used for the pellet tray while still achieving the desired distribution as described above. In some examples, the pellet tray may generally match the profile of the fuel lattice 100.

[0042] In the example shown in FIG. 4 , the outer rim 230 includes an upper lip or rollover 410 and a lower edge 420. The upper lip or rollover 410 can provide a user-friendly edge, such as for easy gripping, lifting, and lowering. In some examples, the lower edge 420 can contact an outer portion 430 of the fuel lattice 100, for example, when the pellet adapter 200 is lowered onto the fuel lattice 100. Similarly, the recesses or legs 340 can be sized and shaped to contact a middle portion 435 and / or an outer portion 430 of the fuel lattice 100 when the pellet adapter 200 is lowered onto the fuel lattice 100. In some examples, the fuel lattice 100 includes a protrusion upon which the pellet adapter 200 can rest.

[0043] The outer retaining rim 230, recesses or legs 340, and bottom 350 of central protrusion 345 are features that can be stamped from a single sheet metal blank that comprises, for example, pellet tray 320. This allows the structure to be lightweight and inexpensive to manufacture and ship. These features also provide substantial rigidity to pellet adapter 200, allowing it to withstand distortion and deformation at high operating temperatures and rapid temperature cycling.

[0044] The pellet adapter 200 has an outer diameter D and an overall height H, as shown in FIG. 4. The diameter D can be selected so that the pellet adapter 200 fits over the top of the fuel grid 100 and fits within the inner wall or inner body 110 (see FIG. 2), while leaving a gap 210 between the outer retaining rim 230 and the inner body 110 (see FIG. 2). The ratio of D to H can be selected, for example, based on the diameter D, such that the height H is relatively similar between different stove sizes, while the diameter D increases in proportion to the inner diameter of the inner body 110. Thus, a pellet adapter for a large stove may have a relatively large ratio of D to H, while a pellet adapter for a small stove may have a relatively small ratio of D to H. This advantageous configuration promotes long, slow, even, and relatively smokeless combustion of biomass pellets and other similar fuels (e.g., wood or paper pellets, wood chips, construction waste, etc.), thereby maintaining consistent heat, light, and atmosphere from the stove over long periods of time, thereby enhancing user comfort and enjoyment in backyards, campsites, outdoor table settings, etc.

[0045] Depending on the embodiment, the outer diameter D of the pellet adapter 200 can be between 6 inches and 50 inches, although other larger or smaller diameters may alternatively or additionally be used. Depending on the embodiment, the overall height H can be between 4 inches and 12 inches, although other larger or smaller heights may alternatively or additionally be used. Exemplary D / H ratios may vary from 0.5 (e.g., for a small stove) to 15.0 (e.g., for a large fire pit), although other larger or smaller ratios may alternatively or additionally be used.

[0046] It should be noted that although the fuel grate and pellet adapter are both shown as circular in FIG. 4, in other embodiments the stove, fuel grate, and / or pellet adapter may be non-circular, including, but not limited to, shapes such as triangular, square, rectangular, polygonal, or oval.

[0047] 5 and 6 illustrate exploded views of a pellet adapter according to at least one embodiment of the present disclosure. In the illustrated example, the upper portion 360 is a separate component from the lower portion 350, but can be removably attached to the lower portion 350 via a retaining lip 510 and fastener 540 and secured via holes 530 in fold-over tabs 520 on both the lower portion 350 and the upper portion 360. By enabling the central protrusion to be separated into the bottom portion 350 and the upper portion 360, the exemplary pellet adapter of FIG. 5 advantageously allows the pellet adapter 200 to be disassembled. Additionally, the shape of the bottom portion 350 and the upper portion 360 allows the upper portion 360 to be inserted and stored within the bottom portion 350, as shown in FIG. 6. Nesting the upper portion 360 within the lower portion 350 reduces the overall height H (FIG. 4). This reduces the outer packaging diameter, requiring less storage and packaging space, and also reduces the outer shipping diameter and associated shipping costs. An end user, retailer, manufacturer, or other party can assemble the lower portion 350 and upper portion 360 using the fasteners described herein or alternative fasteners. In some embodiments, fasteners 540 are not required, and the upper portion 360 simply rests on the lower portion 350 or is held on the lower portion 350 by a friction fit, thread fit, locking fit, or other means. Note that in some embodiments, the pellet adapter 200 can be comprised of more or fewer than two parts. For example, excluding the fasteners, the pellet adapter 200 can have one, three, four, or more parts.

[0048] FIG. 7 shows the pellet adapter 200 with the upper 360 and lower 350 portions of the central protrusion 345 assembled together, and a plurality of fuel pellets 610 (e.g., wood pellets, paper pellets, wood chips, pelletized waste wood, etc.) dispersed on the pellet tray 320.

[0049] The advantageous configuration of the pellet tray 320, outer retaining edge 230, bottom 350, and top 360 facilitates the dispersion of fuel pellets 610 in a distribution that favorably influences combustion, thereby enabling an attractive, long-lasting flame 620 while minimizing smoke production. Additionally, in the example shown in FIG. 5 , the central hub 440 of the top 360 includes openings in the handle 302 (e.g., two openings, although more or fewer openings may alternatively or additionally be provided). These openings in the handle 302 advantageously provide airflow through the central portion of the fuel grid and upward through the bottom 350 and top 360. This additional airflow helps promote secondary combustion of unburned volatile organic compounds (VOCs) emitted by the fuel pellets 610 during combustion. As discussed above, such secondary combustion can advantageously increase heat and light output while reducing smoke production, thus maximizing the energy content of the fuel pellets 610 and creating an environment with both a warm temperature and a warm, flame-lit atmosphere for as long as possible for a given mass or volume of fuel. In some embodiments, as discussed above, the opening in the handle 302 also functions as a finger hole to facilitate gripping, lifting, and lowering the pellet adapter 200.

[0050] As the fuel pellets burn, the resulting ash and other combustion by-products can fall through the holes 330 (see FIG. 3) onto the fuel grate 100 (see FIG. 1) or through the fuel grate 100 onto the ash pan 180.

[0051] 8 is an exploded view showing, in a partially exploded arrangement, some major components of an exemplary combustion stove system 80', also referred to as a fire pit system. The combustion stove system 80' shown here includes a combustion stove, shown as a fire pit 150', a pellet adapter 200' that removably fits within a combustion chamber 190' of the fire pit 150', and a flame ring 115' that may be positioned on top of the fire pit 150'. This example also includes a stand 710 on which the fire pit 150' rests.

[0052] FIG. 9 illustrates a combustion stove system 80' with a wood-burning fire pit 150' including a pellet adapter 200' atop a fuel grate 100', according to at least one embodiment of the present disclosure. Similar to the fire pits 150 described herein, the fire pit 150' includes an inner body 110', an outer wall 120', an outer or lower vent 122', an inner or upper vent 124', a central axis 270, and a fuel grate 100'. In the example shown in FIG. 7, the fire pit 150' is a tabletop fire pit that rests on a stand 710. The stand 710 allows the fire pit 150' to be placed on a tabletop or other surface (e.g., a tablecloth, forest floor, etc.) without the surface heating up to a level that is hazardous, damaging, or concerning. In the illustrated embodiment, the fuel grate 100 may be a flat mesh of welded rod stock, for example, with openings much larger than those of typical biomass or other fuel pellets. For example, the holes have widths ranging from approximately 6 to 20 mm, although larger and smaller holes are also contemplated. Meanwhile, a pellet adapter 200' is mounted on top of the fuel grate 100' within the cavity or combustion chamber 190' and configured to support the fuel pellets as described above with reference to FIG. 7 while providing the same advantageous airflow and secondary combustion described above with reference to FIG. 2. In some examples, the fire pit 150' may be similar in some or all respects to the stove described in U.S. Patent Application No. 17 / 886,239, filed August 11, 2022, which is incorporated herein by reference in its entirety. Some previously described reference numerals are reappearing in FIG. 9, and the above descriptions apply equally to the embodiment of FIG. 9. For example, the description of the gap 210 may also apply to the gap 210', etc.

[0053] FIG. 10 is a front perspective view of the exemplary pellet adapter 200′ of FIG. 9 in accordance with at least one embodiment of the present disclosure. In the example shown in FIG. 10 , the pellet adapter 200′ includes a flat or substantially flat pellet tray 320′, which also includes an outer retaining rim 230′ having a vent hole 810 similar to the vent hole 330 of the pellet tray 320. Additionally, the pellet adapter 200′ also includes a bottom 350′ of a central protrusion 345′ having a vent hole 820, which may be similar to or different from the vent holes 330 and 810 described above, and in either case, sized and shaped to prevent the passage of unburned fuel pellets. Similarly, an upper portion 360′ of the central protrusion 345′ may include a vent hole 830, which may be similar to or different from the vent holes 330 and 810, and which may be sized and shaped to prevent the passage of unburned fuel pellets.

[0054] Depending on the embodiment, the lower portion 350' and upper portion 360' of the central projection 345' may be fixedly attached to each other and to the pellet tray 320'. Because this exemplary pellet adapter 200' is intended for use with a small tabletop stove, the ratio of its outer diameter D to its overall height H is relatively small.

[0055] FIG. 11 is a front perspective view of an exemplary pellet adapter 200″ for a wood-burning stove, according to at least one embodiment of the present disclosure. Shown are an outer rim 230″, an upper lip or turnup 410″, a bottom edge 420″, a pellet tray 320″, a recess (e.g., a foot or leg) 340″, a bottom 350″, an upper 360″, a vent 330″, and a vent formed as a handle 302″. In the example shown in FIG. 11, the pellet adapter 200″ has a medium ratio of outer diameter D to overall height H, making it suitable for use in, for example, a medium-sized wood-burning stove. The above description of the pellet adapter 200 described with reference to FIGS. 1-7 also applies to the pellet adapter 200″.

[0056] FIG. 12 is a front perspective view of an exemplary pellet adapter 200 for a wood-burning stove, according to at least one embodiment of the present disclosure. Shown are the outer rim 230'", the upper lip or turnup 410'", the bottom edge 420'", the pellet tray 320'", the recess (e.g., foot or leg) 340'", the bottom 350'", the top 360'", the vent 330'", and the vent 302'" formed as a handle. In the example shown in FIG. 12, the pellet adapter 200 has a large ratio of outer diameter D to overall height H, making it suitable for use with, for example, a large wood-burning stove or a small fire pit. The above description of the pellet adapter 200 described with reference to FIGS. 1-7 also applies to the pellet adapter 200".

[0057] FIG. 13 is a front perspective view of an exemplary pellet adapter 200'''' for a wood-burning stove, according to at least one embodiment of the present disclosure. Shown are the outer rim 230'''', the upper lip or turnup 410'', the bottom edge 420'', the pellet tray 320'', the recess (e.g., foot or leg) 340'', the bottom 350'', the top 360'', the vent 330'', and the vent 302'''' formed as a handle. In the example shown in FIG. 10, the pellet adapter 200 has a large ratio of outer diameter D to overall height H, making it suitable for use in, for example, a large fire pit. The above description of the pellet adapter 200 described with reference to FIGS. 1-7 also applies to the pellet adapter 200''.

[0058] In use, a user can adapt or convert a log or stick burning stove, such as a fire pit, into a pellet burning stove. The log or stick burning stove can include a combustion chamber with a fuel grate therein. The fuel grate can have holes configured to allow air or ash to pass therethrough, the holes having a first width that does not restrict or prevent the passage of fuel pellets. The method includes gripping a pellet adapter with a handle, the pellet adapter having a pellet tray with a plurality of vent holes having a second width smaller than the first width, the second width sized to restrict or prevent the passage of fuel pellets; introducing the pellet adapter into an upper opening of the combustion chamber of the log or stick burning stove; and depositing fuel pellets onto the pellet tray for combustion.

[0059] In some aspects of the method, the step of introducing the pellet adapter into the upper opening of the combustion chamber includes positioning the pellet adapter on the fuel grate, and the pellet adapter may be offset from the fuel grate to allow air to flow between the fuel grate and the pellet adapter.

[0060] A user can adapt or convert a pellet burning stove, such as a fire pit, back into a log or stick burning stove by reversing the above process, grasping the handle and lifting the pellet adapter vertically through the combustion chamber and its opening from a position inside the combustion chamber to a position outside the combustion chamber.

[0061] It can thus be seen that the pellet adapters described herein fulfill a long-standing need in the art by providing a low-cost, lightweight, punchable, high-strength, high-rigidity, high-airflow structure that enables a conventional wood-burning stove or fire pit to function as a pellet-burning stove without modification, thereby enabling the stove or fire pit to take advantage of the portability, storability, and high energy density of pelletized fuel, with resulting benefits in versatility, heat and light output, and ambiance.

[0062] Various variations on the above examples and embodiments are possible. For example, the pellet adapter can be made of a heavier gauge material to support more weight, or a lighter gauge material to make it lighter and more portable. The pellet adapter can be made in different sizes and / or with different degrees of curvature. The relative lengths, widths, and radii of different components can differ from those shown herein. The pellet adapter can be made by various processes, such as casting, forging, sintering, milling, and 3D printing. It can be made of different metals or non-metallic materials, such as ceramics. The outer rim can be non-circular, including shapes such as oval, rectangular, triangular, and diamond. The technology described herein can be used to burn firewood, wood chips or pellets, waste wood, paper, cardboard, coal, and other combustible materials. It can be used, for example, in lamps, stoves, fire pits, fireplaces, furnaces, forges, boilers, and other combustion heaters. In some embodiments, multiple pellet adapters may be used, or the pellet adapter may be comprised of multiple pieces that collectively form a structure as described herein.

[0063] The logical operations making up the embodiments of the technology described herein are referred to variously as operations, steps, objects, elements, components, modules, etc. Moreover, it should be understood that they may be performed in any order unless expressly stated otherwise or unless a particular order is inherently required by claim language.

[0064] All directional references, such as top, bottom, inner, outer, upward, downward, left, right, lateral, front, rear, top, bottom, upper, lower, vertical, horizontal, clockwise, counterclockwise, proximal, distal, etc., are used for identification purposes only to aid the reader in understanding the claimed subject matter and are not intended to imply any limitations, particularly with respect to the location, orientation, or use of a fuel grid. References to connections, such as attached, coupled, connected, and coupled, should be interpreted broadly and, unless otherwise indicated, may include intermediate members between sets of elements and relative movement between elements. Thus, references to connections do not necessarily imply that two elements are directly connected and in a fixed relationship to one another. The term "or" should be interpreted to mean "and / or" rather than "exclusive or." Unless otherwise stated in the claims, listed values ​​should be interpreted as exemplary only and not limiting.

[0065] The above specification, examples, and data provide a complete description of the structure and use of exemplary embodiments of the pellet adapter defined in the claims. While various embodiments of the claimed subject matter have been described above with some detail or with reference to one or more specific embodiments, those skilled in the art will be able to make numerous modifications to the disclosed embodiments without departing from the spirit or scope of the claimed subject matter. Still other embodiments are contemplated. All matter contained in the above description or shown in the accompanying drawings is intended to be interpreted only as illustrative of particular embodiments and not limiting. Changes in detail or arrangement may be made without departing from the basic elements of the subject matter defined in the following claims.

Claims

1. A stove, A combustion chamber; a fuel grid disposed within the combustion chamber, the fuel grid having a plurality of first vent holes sized to allow fuel pellets to pass therethrough; a pellet adapter removably positionable on the fuel grate within the combustion chamber, the pellet adapter comprising: a pellet tray having a plurality of second vent holes sized and shaped to prevent passage of the fuel pellets; With a raised outer rim, a central projection having a height greater than the height of the raised outer rim; the pellet adapter; Stove

2. 10. The stove of claim 1, wherein the pellet adapter further comprises a plurality of recesses.

3. 3. The stove of claim 2, wherein the pellet tray has a handle that can be gripped by a user.

4. 3. The stove of claim 2, wherein the recess has a foot that contacts the fuel grate when the pellet adapter is placed on the fuel grate in the combustion chamber.

5. 2. The stove of claim 1, wherein the central projection has a lower portion fixedly attached to the pellet tray and an upper portion removably attached to the lower portion.

6. 2. The stove of claim 1, wherein the central projection has a plurality of third vent holes sized and shaped to prevent the passage of the fuel pellets therethrough.

7. 2. The stove of claim 1, wherein said central projection has a frustoconical shape.

8. 2. The stove of claim 1, wherein said pellet tray has a frustoconical shape.

9. 2. The stove of claim 1, wherein the raised outer rim has a plurality of fourth vent holes sized and shaped to prevent the passage of the fuel pellets.

10. 2. The stove of claim 1, wherein when the pellet adapter is placed on the fuel grate in the combustion chamber, a gap exists between the raised outer rim and the inner wall of the combustion chamber.

11. 3. The stove of claim 2, wherein when the pellet adapter is placed on the fuel grate in the combustion chamber, the lower end of the raised outer rim contacts the fuel grate.

12. A pellet adapter for adapting a wood stove to a pellet-burning stove, comprising: a pellet tray having a plurality of vent holes sized and shaped to prevent the passage of fuel pellets therethrough; With a raised outer rim, a central projection having a height greater than the height of the raised outer rim; and the pellet adapter is removably positionable on a stove fuel grate within the stove combustion chamber; Pellet adapter.

13. 13. The pellet adapter of claim 12, further comprising a plurality of recesses formed in the pellet tray.

14. 14. The pellet adapter of claim 13, wherein the recess has feet that contact the fuel grate when the pellet adapter is placed on the fuel grate in the combustion chamber.

15. 13. The pellet adapter of claim 12, wherein the central protrusion has a lower portion fixedly attached to the pellet tray and an upper portion removably attached to the lower portion.

16. 13. The pellet adapter of claim 12, wherein at least one of the central projection or the raised outer rim has a plurality of third vent holes sized and shaped to prevent passage of the fuel pellets.

17. 13. The pellet adapter of claim 12, wherein the central projection has a frustoconical shape.

18. 13. The pellet adapter of claim 12, wherein the pellet tray has a frustoconical shape.

19. 13. The pellet adapter of claim 12, wherein when the pellet adapter is placed on the fuel grate in the combustion chamber, a gap exists between the raised outer rim and an inner wall of the combustion chamber, and a lower end of the raised outer rim contacts the fuel grate.

20. 1. A pellet adapter for adapting a log or stick burning stove to a pellet burning stove, the log or stick burning stove including a combustion chamber with a fuel grate therein, the fuel grate having holes configured to allow air or ash to pass therethrough, the holes having a first width that does not restrict or prevent the passage of fuel pellets, the pellet adapter comprising: a pellet tray sized to removably fit within the combustion chamber, the pellet tray having a plurality of vent holes having a second width less than the first width, the second width sized to inhibit or prevent passage of the fuel pellets; a handle on the pellet tray that can be grasped by a user to insert or remove the pellet tray from the combustion chamber to adapt the stove to a pellet-burning stove; and 1. A pellet adapter.

21. 21. The pellet adapter of claim 20, a raised outer rim having a first height around the periphery of the pellet tray; a central projection extending from the pellet tray at a second height greater than the first height; 1. A pellet adapter.

22. 22. The pellet adapter of claim 21, wherein the handle is formed as at least one of an opening in the central projection or a graspable handle extending above the pellet tray.

23. 21. The pellet adapter of claim 20, further comprising a plurality of recesses formed in the pellet tray, the recesses forming legs that offset the pellet tray from the fuel grid.

24. 1. A method of adapting a log or stick burning stove to a pellet burning stove, the log or stick burning stove including a combustion chamber with a fuel grate therein, the fuel grate having holes configured to allow air or ash to pass therethrough, the holes having a first width that does not inhibit or prevent the passage of fuel pellets, the method comprising: gripping a pellet adapter with a handle, the pellet adapter sized to fit within the combustion chamber and having a pellet tray, the pellet tray having a plurality of vent holes with a second width less than the first width, the second width sized to inhibit or prevent passage of the fuel pellets; introducing the pellet adapter into an upper opening of the combustion chamber of the log or stick burning stove; depositing fuel pellets onto the pellet tray for combustion; A method having the following.

25. 25. The method of claim 24, wherein the step of introducing the pellet adapter into the upper opening of the combustion chamber includes the step of positioning the pellet adapter on the fuel grate, the pellet adapter being offset from the fuel grate to allow air to flow between the fuel grate and the pellet adapter.

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