Combustible fuel combustion furnace with particle adapter

Abstract

A furnace includes a combustion chamber, a fuel grate positioned within the combustion chamber, and a particle adapter removably positionable on the fuel grate. The fuel grate includes a plurality of first vent holes. The particle adapter includes a plurality of second vents sized and shaped to prevent passage of fuel particles. The particle adapter also includes a raised outer edge and a central bump having a height greater than that of the raised outer edge.

Description

Technical Field

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

[0002] Portable wood-burning stoves (e.g., fire pits) are used for camping, utilizing branches and sticks as fuel for heating and cooking. Likewise, large portable fire pits can be used for entertaining, providing outdoor heat, and supporting limited cooking, such as roasting marshmallows, in places such as residential backyards.

[0003] However, portable wood-burning stoves (including portable fire pits) are typically fueled by a pile of sticks or logs (e.g., firewood) supported by a fuel grate. The fuel grate has structural features sufficient to support the fuel load, which in some cases can be quite heavy, at operating temperatures between about 700°F (371°C) and about 1350°F (732°C). In addition, the fuel grate is typically designed not to flex or deform when thermally cycled between these high operating temperatures and much lower ambient temperatures between about 100°F (38°C) and -40°F (-40°C). However, in order to provide adequate airflow for combustion, the fuel grate will typically have large and / or numerous vents.

[0004] In some cases, wood pellets may be considered advantageous over firewood. Pellets are easy to store in bags or barrels, have a high energy density, and burn more slowly than firewood, providing more even heat, light, and ambiance from the stove over a longer period of time. However, the design features of fuel grates may cause problems for users who want to burn smaller fuel sources, such as wood pellets, because wood pellets may fall through the vents of the fuel grate. In addition, because wood pellets are packed more densely than sticks and logs, there is less space between the pellets for airflow, and a pile of wood pellets may tend to burn from the top down rather than from the bottom up. Therefore, the shape of flat or domed fuel grates may not be conducive to even, smokeless burning of wood pellets, as well as other small fuel items such as paper pellets, wood chips, etc.

[0005] It will therefore be appreciated that such conventional fuel grates suffer from a number of disadvantages including one or more large vent holes, smoke generation, etc. Thus, there remains a long felt need for a fire pit and portable wood burning stove structure that addresses the above-referenced problems and others.

[0006] The information contained in the background section of this specification (including any references cited herein and any description or discussion thereof) is for technical reference purposes only and should not be regarded as subject matter by which the scope of the present disclosure is limited. Summary of the invention

[0007] A pellet adapter for a wood-burning fire pit stove is disclosed. The pellet adapter includes novel structural features to allow the pellet adapter to be mounted on top of a fuel grate within a stove body. The pellet adapter has the function of preventing wood pellets from falling through the vents of the fuel grate and also ensures that the pellets are evenly distributed and burned. The pellet adapter has a particular, but not exclusive, use in allowing wood-burning fire pits and camping stoves to burn pellet fuel.

[0008] A general aspect includes a combustion fire pit stove. The stove includes: a combustion chamber; a fuel grate located within the combustion chamber, the fuel grate including a plurality of first vents; a pellet adapter removably positionable on the fuel grate within the combustion chamber, the pellet adapter including: a pellet tray including a plurality of second vents sized and shaped to prevent passage of fuel pellets; a raised outer edge; and a central ridge having a height greater than a height of the raised outer edge.

[0009] Implementations may include one or more of the following features. In some embodiments, the pellet adapter further includes a plurality of dimples. In some embodiments, the pellet tray includes a handle that a user can grasp. In some embodiments, the dimples include feet that contact the fuel grate when the pellet adapter is located on the fuel grate within the combustion chamber. In some embodiments, a bottom edge of the raised outer edge contacts the fuel grate when the pellet adapter is located on the fuel grate within the combustion chamber. In some embodiments, the central raised portion 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 raised portion includes a plurality of third vents sized and shaped to prevent passage of fuel particles. In some embodiments, the central raised portion includes a truncated cone. In some embodiments, the pellet tray includes a truncated cone. In some embodiments, the raised outer edge includes a plurality of fourth vents sized and shaped to prevent passage of fuel particles. In some embodiments, when the pellet adapter is located on the fuel grate within the combustion chamber, an air gap exists between the raised outer edge and an inner wall of the combustion chamber.

[0010] One general aspect includes a pellet adapter for adapting a wood burning stove to a pellet burning stove. The pellet adapter includes a pellet tray including a plurality of ventilation holes sized and shaped to prevent the passage of fuel pellets; a raised outer edge; and a central ridge having a height greater than the height of the raised outer edge, wherein the pellet adapter is removably placed on a fuel grate of the stove within a combustion chamber of the stove.

[0011] Implementations may include one or more of the following features. In some embodiments, the particle adapter further comprises a plurality of dimples formed in the particle tray. In some embodiments, the dimples comprise feet that contact the fuel grate when the particle adapter is positioned on the fuel grate within the combustion chamber. In some embodiments, the central raised portion comprises a lower portion fixedly attached to the particle tray and an upper portion removably attached to the lower portion. In some embodiments, at least one of the central raised portion or the raised outer edge comprises a plurality of third vents sized and shaped to prevent passage of fuel particles. In some embodiments, the central raised portion comprises a truncated cone. In some embodiments, the particle tray comprises a truncated cone. In some embodiments, when the particle adapter is positioned on the fuel grate within the combustion chamber, an air gap exists between the raised outer edge and an inner wall of the combustion chamber, and a bottom edge of the raised outer edge contacts the fuel grate.

[0012] A general aspect includes a furnace for burning pellet fuel to generate heat. The furnace includes: 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 wall and the outer wall; a chimney formed by the inner wall; a combustion zone within the chimney; at least one vent located within the upper portion of the inner wall; at least one vent located within the lower portion of the outer wall; a fuel grate located within the combustion zone, including a plurality of first vents; and a pellet adapter removably positioned on the fuel grate within the combustion zone, the pellet adapter including: a pellet tray including a plurality of second vents sized and shaped to prevent passage of pellet fuel; a raised outer edge; and a central ridge having a height greater than a height of the raised outer edge.

[0013] In yet other embodiments, 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 having a fuel grate. The fuel grate may have holes configured to allow air or embers to pass through, the holes having a first width that does not inhibit or prevent the passage of fuel particles. The pellet adapter may include: a pellet tray, the pellet tray including a plurality of ventilation holes, the ventilation holes having a second width less than the first width, the second width being sized to inhibit or prevent the passage of fuel particles; and a handle on the pellet tray that can be grasped by a user to introduce the pellet tray into or remove it from the combustion chamber, thereby adapting the stove to a pellet burning stove.

[0014] In some aspects, the pellet adapter can include a raised outer edge having a first height around the pellet tray. In some aspects, the pellet adapter can include a central ridge extending from the pellet tray, the central ridge having a second height greater than the first height. In some aspects, the handle can be formed as at least one of: an opening in the central ridge or a graspable handle extending above the pellet tray. In some aspects, the pellet adapter also includes a plurality of dimples formed in the pellet tray, the dimples forming legs that offset the pellet tray from the fuel grate.

[0015] In yet other embodiments, the present disclosure relates to 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 having a fuel grate. The fuel grate may have holes configured to allow air or embers to pass through, the holes having a first width that does not inhibit or prevent the passage of fuel particles. The method may include: grasping a pellet adapter by a handle, the pellet adapter having a pellet tray, the pellet tray including a plurality of ventilation holes having a second width less than the first width, the second width being sized to inhibit or prevent the passage of fuel particles; introducing the pellet adapter into a top opening of the combustion chamber of the log or stick burning stove; and adding fuel pellets to the pellet tray for combustion.

[0016] In certain aspects of the method, introducing the particle adapter into the top opening of the combustion chamber includes placing the particle adapter onto the fuel grate. The particle adapter may be offset from the fuel grate to allow air to flow between the fuel grate and the particle adapter.

[0017] This summary is intended to introduce a series of concepts in a simplified form that are further described in the detailed description below. 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. Below, the features, details, utilities, and advantages of the fuel grate as defined in the claims are more broadly described through the written description of various embodiments of the present disclosure and the illustration of the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings, in which:

[0019] Figure 1 is a perspective exploded view of an example combustion stove (eg, a wood-burning fire pit) in accordance with at least one embodiment of the present disclosure.

[0020] Figure 2 is a perspective cross-sectional view of an example combustion stove (eg, a wood-burning fire pit) including a pellet adapter located on top of a fuel grate in accordance with at least one embodiment of the present disclosure.

[0021] Figure 3 is a top perspective view of a pellet adapter removably placed within a wood burning stove in accordance with at least one embodiment of the present disclosure.

[0022] Figure 4 is an exemplary illustration of a pellet adapter and fuel grate for a wood burning stove in accordance with at least one embodiment of the present disclosure.

[0023] Figure 5 is a front perspective exploded view of an exemplary pellet adapter for a wood burning stove in accordance with at least one embodiment of the present disclosure.

[0024] Figure 6 is a perspective exploded view of an example particle adapter in accordance with at least one embodiment of the present disclosure.

[0025] Figure 7 is a front perspective view of an exemplary pellet adapter for a wood burning stove in accordance with at least one embodiment of the present disclosure.

[0026] Figure 8 is a perspective exploded view of an example tabletop combustion stove (eg, a wood-burning fire pit) in accordance with at least one embodiment of the present disclosure.

[0027] Fig. 9 is a perspective cross-sectional view of an exemplary tabletop combustion stove (eg, a wood burning stove) including a pellet adapter located on top of a fuel grate in accordance with at least one embodiment of the present disclosure.

[0028] Fig.10 According to at least one embodiment of the present disclosure Figure 7 A front perspective view of an exemplary particle adapter.

[0029] Fig.11 is a front perspective view of an exemplary pellet adapter for a wood burning stove in accordance with at least one embodiment of the present disclosure.

[0030] Fig.12 is a front perspective view of an exemplary pellet adapter for a wood burning stove in accordance with at least one embodiment of the present disclosure.

[0031] Fig.13 is a front perspective view of an exemplary pellet adapter for a wood burning stove in accordance with at least one embodiment of the present disclosure. DETAILED DESCRIPTION

[0032] A pellet adapter for a wood-burning stove is provided that includes novel structural features to allow the pellet adapter to be mounted on top of a fuel grate that can be permanently or removably mounted within the stove body. The pellet adapter includes features that prevent granular biomass fuel (e.g., wood pellets, paper pellets, wood chips, etc.) from falling through the vents of the fuel grate, and also ensures uniform distribution of the fuel pellets and top-down combustion. The disclosed pellet adapter also includes air flow features that facilitate a thorough combustion of the fuel, thereby generating more heat and significantly reducing smoke. The design can be easily manufactured as a single piece (e.g., stamped from a sheet metal blank), or assembled from two stampings (thereby allowing the pellet adapter to be shipped in a smaller container). These configurations allow the pellet adapter to be placed on top of the fuel grate without significantly adding weight or reducing the airflow of the wood-burning stove, while maintaining the portability and / or packability of the stove.

[0033] So for friends gathered around a stove or fire pit, whether at a campsite, picnic table, tailgate party, backyard, or other venue, the stove or fire pit can be easily converted from burning wood to burning biomass pellets or other pelletized fuels by adding a pellet adapter. Pellet fuels are easy to store and transport (e.g., in bags or barrels) and have a high energy density. In addition, the features of the stove and pellet adapter provide favorable airflow, allowing for long periods of heat, light, and ambiance with virtually no smoke, allowing for repeated enjoyment of the outdoor experience. A stove with a pellet adapter may also be beneficial for emergency use when other sources of heat and light are unavailable.

[0034] The pellet adapter includes a vented pellet tray, an outer retaining rim, and a central ridge. Together, these features allow the biomass pellets to be optimally aligned for a top-down, relatively smokeless burn. The pellet adapter also includes a plurality of relief or dimple features that can be used as handles and also as feet for contacting the pellet adapter with the fuel grate while maintaining an air gap between the pellet adapter and the fuel grate.

[0035] In order to promote the understanding of the principles of the present disclosure, reference will now be made to the embodiments shown in the accompanying drawings and specific language will be used to describe the present disclosure. However, it should be understood that this is not intended to limit the scope of the present disclosure. Any changes and further modifications to the devices, systems and methods and any further applications of the principles of the present disclosure, as would normally be expected by a technician in the field to which the present disclosure relates, are fully considered and included in the present disclosure. Specifically, it is entirely conceivable that the features, components and / or steps described for one embodiment can be combined with the features, components and / or steps described for other embodiments of the present disclosure. However, for the sake of brevity, multiple iterations of these combinations will not be described separately.

[0036] These descriptions are for illustrative purposes only and should not be considered to limit the scope of the particle adapter. Certain features may be added, deleted, or modified without departing from the spirit of the claimed subject matter.

[0037] Figure 1 1 is an exploded view showing several major components of an exemplary furnace system 80 (also referred to as a fire pit system) in a partially exploded manner. The furnace system 80 shown here includes: a furnace, shown here as a fire pit 150; a pellet adapter 200, which is removably mounted within a combustion chamber 190 of the fire pit 150; and a flame ring 115, which can be disposed on an upper edge of the fire pit 150.

[0038] Figure 2 is a perspective cross-sectional view of an example combustion furnace system 80, in this example shown as a wood-burning fire pit system, with a pellet adapter 200 disposed in the combustion chamber 190. Figure 1 and Figure 2 , the fire pit 150 may include a fire grate or fuel grate 100 disposed within the fire pit 150 and supporting the weight of fuel (e.g., firewood, sticks, and other fuels) while allowing air to flow through the fuel grate 100 and the fire pit 150 to promote combustion of the fuel. Figure 1 In the illustrated embodiment, the fuel grate is made of a sheet of metal having openings therein for the passage of air and embers. The fuel grate 100 is strong and rigid, capable of bearing the weight of wood and other fuels at both ambient and operating temperatures, and, due at least in part to its slightly domed shape, resists significant warping or other significant deformation despite repeated exposure to combustion heat over long periods of time. The fuel grate 100 may also be lighter and have a greater airflow capacity than other fuel grates of comparable size.

[0039] exist Figure 2In the exemplary embodiment of the present invention, the fire pit 150 includes a top 152, a bottom 154, and a middle portion 156. The fire pit 150 also includes an inner wall or inner body 110, an outer wall or outer body 120, a connecting ring 125 located in the top 152 of the fire pit 150 and attached to or formed as a single piece with the inner body 110 and / or the outer body 120, and a combustion chamber 190 defined by the inner body 110, and the fuel grate 100 is located in the combustion chamber 190. The fire pit 150 also includes a flame ring 115, which can help drive airflow toward the central axis 270 when the fire pit 150 is in use. The shape and size of the flame ring are designed to help a cleaner burn by directing air in the manner described herein. The fire pit 150 also includes a plurality of external vents 122 located at the bottom 154 of the outer body 120, and a plurality of internal vents 124 located at the top 152 of the inner body 110. In the middle portion 156 of the fire pit 150 , the inner body 110 terminates in a radially inwardly projecting rim that may support the ash pan and fuel grate 100 .

[0040] The fire pit 150 also includes a base plate 170 attached to the outer body 120, a support tray 175 supported or suspended from the inner body 110 by brackets protruding upward from the base plate, and a collection tray or ash tray 180 supported by brackets protruding upward from the support tray 175 and also otherwise suspended from the inner body 110, such that the support tray 175 is separated from the outer body 120 by an air gap 176, the ash tray 180 is separated from the outer body 120 by an air gap 178, and the inner body is separated from the outer body by an air gap 179. In one example, the air gaps 176 and 179 are both approximately 50 millimeters, and the air gap 178 is approximately 100 millimeters, although other air gaps may be used with the disclosed advantageous effects.

[0041] like Figure 2 As shown, the support tray 175 includes a vent 177 which, in the example shown, is centrally located directly below the ash pan 180 .

[0042] Cavity 190 is in fluid communication with air gap 179 via inner vent 124. Cavity 190 is in fluid communication with air gaps 178 and 176 through fuel grate 100. Air gaps 176 and 178 are in fluid communication with ambient air through outer vent 122, such that ambient air may be drawn in through outer vent 122, heated by the combustion of the fuel, and exhausted through cavity 190 and inner vent 124 to produce a favorable fuel combustion. In some examples, the fire pit may be similar in some or all respects to the fire pit described in U.S. Application No. 17 / 169,269, filed on February 5, 2021, which is incorporated herein by reference in its entirety.

[0043] In one example, the fuel grate 100 and other components of the fire pit 150 are each made of stainless steel sheet 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 of stainless steel having a thickness of 1.0 mm to 2.0 mm, with one example being stainless steel having a thickness of about 1.5 mm. Thicker and thinner materials are both 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 may also be provided. In one example, during normal operation, the fuel grate 100 supports a nominal weight of 100 pounds (45.4 kilograms) (although a nominal capacity between about 5 pounds and about 190 pounds may be provided) while the fuel grate 100 or portions thereof are heated by the combustion of fuel to between about 700°F (371°C) and about 1350°F (732°C) for a period of 1 to 12 hours, and with ambient temperatures as low as -40°F (-40°C). In one example, over many years of normal operation, through repeated cycling (e.g., one hundred cycles) between ambient and operating temperatures, the fuel grate 100 exhibits little or no apparent warping that adversely affects its aesthetics, performance, or fit within the fire pit 150.

[0044] The primary load borne by the fuel grate 100 is applied downwardly in a direction parallel to the axis 270 by the weight of the fuel piled on the fuel grate 100 , while the fuel grate 100 is supported directly or indirectly by the support tray 175 .

[0045] When a fire is lit, the rising hot air and lack of oxygen from the combustion process creates a vacuum at the bottom of the cavity or combustion chamber 190. This vacuum draws oxygen through the vents 122 at the bottom of the outer wall or outer body 120 and upward into the cavity or combustion chamber 190. More specifically, cool outside air may flow inward through the vents 122 and then separate to flow upward toward the vents 124 and laterally inward toward the cavity or combustion chamber 190. The laterally inwardly flowing air may flow between the support tray 175 and the bottom plate 170, through one or more vents 177 in the support tray 175, and around the bottom of the ash pan 180, upward through the fuel grate 100 into the cavity or combustion chamber 190 to support direct (primary) combustion of the fuel. In the illustrated example, the pellet adapter 200 is already in place and in use, and air flows not only through the fuel grate, but also through the pellet adapter into the combustion chamber 190. The structure of the pellet adapter 200, including the airflow openings in the pellet adapter 200, will be further described below. Figure 1 and Figure 2The configuration shown allows for secondary combustion of unburned volatile organic compounds (VOCs) emitted during the combustion of the fuel. This is because additional oxygen flows vertically upward from the vents 122 through the gap 179 between the outer wall or outer body 120 and the inner wall or inner body 110, where the oxygen is preheated by the temperature of the inner body 110. The oxygen then continues to flow back into the cavity or combustion chamber 190 through the upper vents 124 to further burn the VOCs within the hot column and the flames rising in the cavity or combustion chamber 190. The flame ring 115 can help introduce oxygen into the combustion column, thereby generating additional heat and burning the VOCs. This secondary combustion not only increases the heat and light output of the fire pit 150, but also reduces smoke generation by ensuring a more complete combustion of the fuel.

[0046] Figure 2 In accordance with at least one embodiment of the present disclosure, a pellet adapter 200 is shown disposed on top of a fuel grate 100 and in a use position. The pellet adapter 200 is removably positioned on top of the fuel grate 100 within the cavity or combustion chamber 190 such that an air gap 220 is maintained between the fuel grate 100 and the pellet adapter 200, and such that certain portions or features of the pellet adapter 200 are in contact with and supported by the fuel grate 100. In addition, the pellet adapter 200 is shaped and sized such that a raised outer edge or retaining edge 230 of the pellet adapter 200 leaves an air gap 210 between the outer edge or retaining edge 230 and the inner wall or inner body 110. In some embodiments, the pellet adapter 200 may be sized such that the air gap 210 is small enough to inhibit or prevent pellets from falling between the retaining edge 230 and the inner wall or inner body 110. Thus, in some examples, the air gap 210 is in the range of about 1 to 8 millimeters. However, other sizes of air gaps are also contemplated. The air gap 210 may also allow some air to flow between the pellet adapter 200 and the inner wall or body 110, and may also be sized to fit within a user's hand or gripping tool to facilitate gripping of the pellet adapter 200 when placing the pellet adapter 200 into or lifting it from the cavity or combustion chamber 190. Thus, the air gap 210 may also provide clearance so that the pellet adapter 200 can be easily lifted and removed and easily introduced into the combustion chamber 190.

[0047] Adding the pellet adapter 200 to the fire pit 150 and fuel grate 100 advantageously allows the fire pit 150 to burn biomass pellets rather than wood to obtain the above-mentioned advantages of a storable, energy-dense fuel that can burn more evenly over a longer period of time than wood, thereby providing extended desired heat, light, and ambiance from the fire pit 150 while retaining ... Figure 2 Although wood pellets are mentioned herein, it is apparent that any biomass pellets may be used.

[0048] Figure 3-5 The particle adapter is shown in more detail. According to at least one embodiment of the present disclosure, Figure 3 The pellet adapter 200 is shown removably placed within the fire pit 150. Figure 4 The pellet adapter 200 is shown to be disposed above the fuel grate. When in use, the pellet adapter 200 can be placed on the fuel grate. Figure 5 An example is shown in which the particle adapter 200 is in a disassembled state.

[0049] refer to Figures 3 to 5 , the pellet adapter 200 includes a raised outer edge or pellet retaining edge 230 and a pellet tray 320 including a plurality of ventilation holes 330. The outer edge or pellet retaining edge 230 can, for example, be part of or formed together with the pellet tray 320 and can be advantageously used to prevent wood pellets or other fuels from rolling off the sides of the pellet tray 320. The pellet tray 320 also includes a plurality of ventilation holes 330, the size and shape of which are selected so that biomass pellets or similar solid fuels are not easily dropped through the holes. The holes 330 can, for example, be smaller than the holes in the fuel grate 100 (see Figure 1 ). In some examples, the ventilation holes 330 are sized to have a width in the range of about 1 to 5.5 millimeters, thereby preventing particles with a width of 6 millimeters or more from passing through. In some embodiments, the ventilation holes 330 are sized to have a width in the range of about 1 to 7.5 millimeters, thereby preventing particles with a width of 8 millimeters or more from passing through. Other sizes are also contemplated to accommodate particles of different sizes. Conversely, the ventilation holes in the fuel grate may be sized to be larger than 8 millimeters, and may allow particles with a width of 8 millimeters or less to pass through.

[0050] In order for pellet adapter 200 to provide similar airflow as fuel grate 100 , there may be more ventilation holes 330 in pellet tray 320 of pellet adapter 200 than in fuel grate 100 , such that the total area of ​​holes 330 may be similar to the total area of ​​holes in fuel grate 100 .

[0051] exist Figure 3-5In the example shown, the pellet adapter 200 also includes a plurality of dimples or legs 340 (also referred to as feet) that, in some embodiments, may extend below the major surface of the pellet tray 320 and cooperate to offset the bottom surface of the pellet tray 320 from the fuel grate 100. This may provide an air passage between the pellet adapter 200 and the fuel grate 100 so that air can flow not only at the side edges of the pellet adapter 200, but also through the fuel grate to all vents 330 to achieve continuous combustion. Here, the legs 340 are dimples formed in the pellet tray 320, but in other embodiments, the legs 340 may be attached to the pellet tray or otherwise arranged to offset the pellet tray 320 from the fuel grate 100.

[0052] The example pellet adapter 200 described herein also includes a handle 302 that a user can grasp (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). Here, the handle 302 is centrally located and formed by two openings into which a tool or a user's fingers can be inserted to grasp the pellet adapter. However, other handles are also contemplated. The handle 302 is disposed at a height above the pellet tray 320 so that the handle can be grasped even when pellets are in the pellet tray 320.

[0053] In the example shown, the pellet adapter 200 also includes a central raised portion 345 (e.g., a truncated cone) that prevents wood pellets from stacking at or near the center of the pellet tray 320. This allows the wood pellets to be easily stacked in a ring around the circumference of the pellet tray 320, which may be an advantageous arrangement for a slow, even, relatively smokeless burn. The central raised portion 345 may, for example, include a bottom portion 350, which may be part of or formed with the pellet tray 320, and a top portion 360, which is removably attached to the bottom portion 350. However, in other embodiments, the central raised portion 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 formed with the pellet tray 320. The height of the top portion 360 is generally greater than the height of the raised outer edge 230, so that the overall height of the pellet adapter 200 is defined by the central raised portion 345 rather than the outer edge 230. In the example shown, the handle 302 is located at the apex of the raised portion 345.

[0054] Still refer to Figures 3 to 5, the central ridge 345 is generally shaped as a truncated cone that is wider at the bottom and narrower at the top. The top 360 includes a central hub 440, which can be, for example, a part of the top 360 or formed together with the top 360. In addition, the particle tray 320 is inclined so that it also takes the shape of a general truncated cone, although it is shorter, flatter or shallower than the truncated cone of the central ridge 345. This arrangement can, for example, promote an ideal distribution of fuel particles, where when the particles are poured onto the particle tray 320 under the influence of gravity, the particle pile may naturally tend to be deeper near the outer edge 230 of the particle adapter 200, shallower near the central ridge 345, and not exist on the slope of the central ridge. The resulting distribution 450 can, for example, be approximately wedge-shaped in cross section and approximately annular when viewed from above, which can promote more combustion near the outer retaining edge 230 and less combustion near the central ridge 345. It should be appreciated that other inclined shapes of the particle tray, including dome or pyramid shapes, may alternatively or additionally be used while still achieving the advantageous distribution described above. In some examples, the particle tray may generally match the contour of the fuel grate 100 .

[0055] exist Figure 4 In the example shown, the outer edge 230 includes a top lip or flip 410 and a bottom edge 420. The top lip or flip 410 can, for example, provide a user-friendly edge that is easy to grab, lift, put down, etc. In some examples, when the pellet adapter 200 is lowered onto the fuel grate 100, the bottom edge 420 can, for example, contact the outer portion 430 of the fuel grate 100. Similarly, the dimples or legs 340 can be sized and shaped to contact the middle portion 435 and / or the outer portion 430 of the fuel grate 100 when the pellet adapter 200 is lowered onto the fuel grate 100. In some examples, the fuel grate 100 includes a protrusion on which the pellet adapter 200 can be placed.

[0056] The outer retaining edge 230, the dimples or legs 340, and the bottom 350 of the central raised portion 345 can, for example, be features stamped from a single sheet metal blank that includes the particle tray 320. Thus, the structure is lightweight and can be manufactured and shipped at low cost. These features can also add considerable rigidity to the particle adapter 200, making it resistant to warping or deformation under high operating temperatures and rapid temperature cycling.

[0057] The particle adapter 200 has an outer diameter D and an overall height H, such as Figure 4 The diameter D can be selected so that the particle adapter 200 fits on top of the fuel grate 100 and is located within the inner wall or body 110 (see Figure 2 ), while leaving an air gap 210 between the outer retaining edge 230 and the inner body 110 (see Figure 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 proportionally with the inner diameter of the inner body 110. Thus, a pellet adapter for a larger stove can have a relatively larger ratio of D to H, while a pellet adapter for a smaller stove can have a relatively smaller ratio of D to H. This advantageous arrangement can promote long, slow, even, and relatively smokeless burning of biomass pellets and other similar fuels (e.g., wood or paper pellets, wood chips, construction waste, etc.), thereby facilitating the stove to continue to generate heat, light, and ambience for a long period of time, which can increase the comfort and enjoyment of users in backyards, campsites, outdoor dining tables, and the like.

[0058] Depending on the implementation, the outer diameter D of the pellet adapter 200 may be between 6 inches and 50 inches, although other diameters, larger or smaller, may be used instead or in addition. Depending on the implementation, the overall height H may be between 4 inches and 12 inches, although other heights, larger or smaller, may be used instead or in addition. For example, the D / H ratio may vary from 0.5 (e.g., for a small furnace) to 15.0 (e.g., for a large fire pit), although other ratios (larger or smaller) may be used instead or in addition.

[0059] It is worth noting that although Figure 4 The fuel grate and pellet adapter shown in FIG. 5 are both circular, but in other embodiments, the furnace, fuel grate and / or pellet adapter may be non-circular, including but not limited to triangular, square, rectangular, polygonal, or elliptical shapes.

[0060] Figure 5 and Figure 6 An exploded view of a pellet adapter according to at least one embodiment of the present disclosure is shown. In the example shown, the top portion 360 is a separate piece from the bottom portion 350, but can be removably connected to the bottom portion 350 by a retaining lip 510 and a fastener 540 that can be secured through holes 530 in the folded tabs 520 in the bottom portion 350 and the top portion 360. By making the central ridge separable into the bottom portion 350 and the top portion 360, Figure 5 The example particle adapter of the invention advantageously allows for the removal of the particle adapter 200. In addition, the shapes of the bottom 350 and the top 360 allow the top 360 to be introduced and stored within the bottom 350, such as Figure 6 As shown. Nesting the top 360 in the bottom 350 can reduce the overall height H ( Figure 4). This may result in a smaller packaging envelope, thereby requiring less storage space, less packaging space, and a smaller shipping envelope, thereby reducing shipping costs. An end user, retailer, manufacturer, or other party may assemble bottom 350 and top 360 using the fasteners described herein or using alternative fasteners. In some embodiments, fasteners 540 are not required, and top 360 simply rests on top of bottom 350 or is retained on bottom 350 by a friction fit, screw fit, locking fit, or other means. It is noteworthy that in some embodiments, particle adapter 200 may include more or less than two components. For example, without fasteners, particle adapter 200 may have one, three, four, or more components.

[0061] Figure 7 Pellet adapter 200 is shown with top 360 and bottom 350 of central raised portion 345 assembled together and a plurality of fuel pellets 610 (eg, wood pellets, paper pellets, wood chips, pelletized waste wood, etc.) distributed over pellet tray 320 .

[0062] Due to the advantageous configuration of the particle tray 320, the outer retaining edge 230, the bottom 350 and the top 360, the fuel particles 610 are easily dispersed in a distribution pattern that is conducive to combustion, thereby allowing the production of an attractive, long-lasting flame 620 while generating minimal smoke. Figure 5 In the example shown, the central hub 440 of the top 360 includes openings (e.g., two openings, although more or fewer openings may be provided instead or in addition) for the handle 302. These openings leading to the handle 302 can be advantageous in providing air flow through the central portion of the fuel grate and upward through the bottom 350 and the top 360. This additional airflow may help promote secondary combustion of unburned volatile organic compounds (VOCs) emitted by the fuel pellets 610 during the combustion process. As described above, such secondary combustion can be advantageous in increasing the output of heat and light while reducing the output of smoke, thereby maximizing the energy content of the fuel pellets 610 and creating an environment with a warm temperature and a warm firelight atmosphere for as long as possible for a given mass or volume of fuel. In some embodiments, as described above, the openings of the handle 302 can also be used as finger holes to facilitate grasping, lifting and lowering the pellet adapter 200.

[0063] Once the fuel particles have burned, the resulting ash or other combustion byproducts will pass through the holes 330 (see Figure 3 ) falls onto the fuel grate 100 (see Figure 1 ) or falls onto the ash pan 180 through the fuel grate 100.

[0064] Figure 8is an exploded view showing several major components of an example furnace system 80' (also referred to as a fire pit system) in a partially exploded manner. The furnace system 80' shown here includes a furnace shown as a fire pit 150', a pellet adapter 200' removably mounted within a combustion chamber 190' of the fire pit 150', and a flame ring 115' that can be disposed on an upper edge of the fire pit 150'. The example also includes a stand 710 on which the fire pit 150' can be placed.

[0065] Fig. 9 A combustion furnace system 80' having a wood-burning fire pit 150' is shown, including a pellet adapter 200' located on top of a fuel grate 100', in accordance with at least one embodiment of the present disclosure. Similar to the fire pit 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'. Figure 7 In the example shown, the fire pit 150' is a tabletop fire pit that is placed on a stand 710. The stand 710 enables the fire pit 150' to be placed on a tabletop or other surface (e.g., a tablecloth, forest floor, etc.) without heating the surface to a dangerous, damaging, or worrisome level. In the illustrated embodiment, the fuel grate 100 can, for example, be a flat grid of welded rods having mostly empty space with openings that are much larger than typical biomass pellets or other fuel pellets. For example, the width of the holes can be in the range of approximately 6-20 mm, although larger or smaller holes are also contemplated. However, the pellet adapter 200' is mounted on top of the fuel grate 100', located within the cavity or combustion chamber 190', and is configured as described above with reference to Figure 7 As shown, the fuel particles are supported while allowing similar Figure 2 The favorable airflow described, and the secondary combustion as described above. In some examples, the fire pit 150' may be similar in some or all respects to the stove described in U.S. Application No. 17 / 886,239 filed on August 11, 2022, which is incorporated herein by reference in its entirety. Fig. 9 Certain reference numerals previously described are reiterated in the text and the above description also applies to Fig. 9 For example, the description of air gap 210 may apply to air gap 210', and so on.

[0066] Fig.10 According to at least one embodiment of the present disclosure Fig. 9 A front perspective view of an exemplary particle adapter 200'. Fig.10In the example shown, the pellet adapter 200' includes a flat or nearly flat pellet tray 320', and the pellet adapter 200' also includes an outer retaining edge 230' having ventilation holes 810 similar to the ventilation holes 330 in the pellet tray 320. In addition, the pellet adapter 200' also includes a bottom 350' of a central raised portion 345' having ventilation holes 820, which may be similar or different than the ventilation holes 330 and 810 described above, but in any case may be sized and shaped so that unburned fuel particles cannot pass through them. Similarly, the top 360' of the central raised portion 345' may include ventilation holes 830, which may be similar or different than the ventilation holes 330 and 810, and which are sized and shaped to prevent the passage of unburned fuel particles.

[0067] Depending on implementation, bottom 350' and top 360' of central ridge 345' may be fixedly connected to each other and to pellet tray 320'. Because this example pellet adapter 200' is used in a small tabletop stove, the ratio of its outer diameter D to its overall height H is relatively small.

[0068] Fig.11 is a front perspective view of an exemplary pellet adapter 200" for a wood burning stove in accordance with at least one embodiment of the present disclosure. Visible are outer edge 230", top lip or flip 410", bottom edge 420", pellet tray 320", recess (e.g., foot or leg) 340", bottom 350", top 360", vent 330", and vent formed as handle 302". Fig.11 In the example shown, the pellet adapter 200" has a moderate ratio of outer diameter D to overall height H, which may make it suitable for use in a medium-sized wood-burning stove, for example. Figure 1-7 The description of the described particle adapter 200 also applies to the particle adapter 200 ″.

[0069] 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. Visible are outer edge 230'", top lip or flip 410'", bottom edge 420'", pellet tray 320'", recess (e.g., foot or leg) 340'", bottom 350'", top 360'", vent 330'", and vent opening formed as handle 302'". Fig.12 In the example shown, the pellet adapter 200 has a larger ratio of outer diameter D to overall height H, which may make it suitable for use with larger sized wood burning stoves or small fire pits, for example. Figure 1-7 The description of the described particle adapter 200 also applies to the particle adapter 200 ″.

[0070] Fig.13 is a front perspective view of an exemplary pellet adapter 200' for a wood burning stove in accordance with at least one embodiment of the present disclosure. Visible are outer edge 230"", top lip or flip 410"", bottom edge 420"", pellet tray 320"", recess (e.g., foot or leg) 340"", bottom 350"", top 360"", vent 330"", and vent formed as handle 302". Fig.10 In the example shown, the pellet adapter 200 has a large ratio of outer diameter D to overall height H, which may make it suitable for use in large fire pits, for example. Figure 1-7 The description of the described particle adapter 200 also applies to the particle adapter 200 ″.

[0071] In use, a user may adapt or convert a log or stick burning stove (e.g., a fire pit) to a pellet burning stove. The wood or stick burning stove may include a combustion chamber having a fuel grate. The fuel grate may have holes configured to allow air or embers to pass through, the holes having a first width that does not inhibit or prevent the passage of fuel particles. The method may include grasping a pellet adapter by a handle, the pellet adapter having a pellet tray, the pellet tray including a plurality of ventilation holes having a second width less than the first width, the second width being sized to inhibit or prevent the passage of fuel particles; introducing the pellet adapter into a top opening of the combustion chamber of the log or stick burning stove; and adding fuel pellets to the pellet tray for combustion.

[0072] In certain aspects of the method, introducing the particle adapter into the top opening of the combustion chamber includes placing the particle adapter onto the fuel grate. The particle adapter may be offset from the fuel grate to allow air to flow between the fuel grate and the particle adapter.

[0073] The user can adapt or convert a pellet burning stove (e.g., a fire pit) back to a log or stick burning stove by reversing the above process, grasping the handle and lifting or raising 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.

[0074] Thus, it can be seen that the pellet adapter described herein meets a long felt need in the art by providing a low cost, lightweight, stampable, high strength, high stiffness, high airflow structure that allows an ordinary wood burning stove or fire pit to be used as a pellet burning stove without modification. This allows the stove or fire pit to take advantage of the portability, storability and high energy density of pellet fuels, thereby providing the advantages of versatility, heat and light output, and ambience.

[0075] There may be many variations of the above examples and embodiments. For example, the particle adapter can be made of a thicker gauge material to support more weight, or made of a thinner gauge material to become lighter and more portable. The particle adapter can be made of different sizes and / or different curvatures. The relative lengths, widths, and radii of different components may be different from those shown herein. The particle adapter can be made by different processes (including casting, forging, sintering, milling, or 3D printing). It can be made of different metals or non-metallic materials such as ceramics. The outer edge can be non-circular, including possible shapes such as ovals, rectangles, triangles, and diamonds. The technology described herein can be used to burn firewood, wood chips or wood pellets, waste wood, paper, cardboard, coal, and other combustible materials. It can be used, for example, in lamps, furnaces, fire pits, fireplaces, furnaces, forges, boilers, and other combustion heaters. In some embodiments, more than one particle adapter can be used, or the particle adapter can include several components that together form a structure as described herein.

[0076] The logical operations that make up the embodiments of the technology described herein are referred to as operations, steps, objects, elements, components, or modules. In addition, it should be understood that these can be performed in any order unless otherwise explicitly required or a specific order is inherently required by the claim language.

[0077] All directional references, such as up, down, inside, outside, upward, downward, left, right, lateral, front, back, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise, proximal and distal, are used for identification purposes only to assist the reader in understanding the claimed subject matter and shall not constitute a limitation, particularly as to the location, orientation or use of the fuel grate. Connection references, such as attached, coupled, connected and joined, shall be interpreted broadly and may include intermediate members between a collection of elements and relative movement between elements, unless otherwise stated. Therefore, connection references do not necessarily mean that two elements are directly connected and have a fixed relationship to each other. The word "or" shall be interpreted as "and / or", not "exclusive or". "Unless otherwise stated in the claims, the values ​​stated shall be interpreted as illustrative only and shall not be considered limiting.

[0078] The foregoing specification, examples, and data provide a complete description of the structure and use of exemplary embodiments of the particle adapter defined in the claims. Although various embodiments of the claimed subject matter have been described above with a certain degree of particularity or with reference to one or more individual embodiments, many modifications may be made to the disclosed embodiments by those skilled in the art without departing from the spirit or scope of the claimed subject matter. Other embodiments are also contemplated. All matter contained in the foregoing description and shown in the accompanying drawings should be construed as illustrative only of particular embodiments and not as limiting. Changes may be made in detail or structure without departing from the basic elements of the subject matter as defined in the following claims.

Claims

1. A furnace comprising: Combustion chamber; a fuel grate located in the combustion chamber, the fuel grate comprising a plurality of first ventilation holes having a size allowing fuel particles to pass therethrough; A pellet adapter removably positionable on a fuel grate within a combustion chamber, the pellet adapter comprising: a particle tray including a plurality of second vents sized and shaped to prevent passage of fuel particles; Raised outer edges; and The height of the central raised portion is greater than the height of the raised outer edge.

2. The furnace of claim 1, wherein the particle adapter further comprises a plurality of dimples.

3. The fire of claim 2, wherein the pellet tray includes a handle that a user can grasp.

4. The fire of claim 2, wherein the recess includes feet that contact the fuel grate when the pellet adapter is positioned on the fuel grate within the combustion chamber.

5. The fire of claim 1 wherein the central raised portion comprises a lower portion fixedly attached to the particle tray and an upper portion removably attached to the lower portion.

6. The furnace of claim 1, wherein the central raised portion includes a plurality of third ventilation holes sized and shaped to prevent passage of fuel particles.

7. The furnace of claim 1 wherein the central raised portion comprises a truncated cone.

8. The fire of claim 1 wherein the particle tray comprises a truncated cone.

9. The fire of claim 1, wherein the raised outer edge includes a plurality of fourth ventilation holes sized and shaped to prevent passage of fuel particles.

10. The fire of claim 1 wherein when the particle adapter is positioned on the fuel grate within the combustion chamber, an air gap exists between the raised outer edge and the inner wall of the combustion chamber.

11. The fire of claim 2, wherein a bottom edge of the raised outer edge contacts the fuel grate when the pellet adapter is positioned on the fuel grate within the combustion chamber.

12. A pellet adapter for adapting a wood burning stove to a pellet burning stove, the pellet adapter comprising: a pellet tray including a plurality of vents sized and shaped to prevent passage of fuel pellets; Raised outer edge; as well as A central raised portion, the height of which is greater than the height of the raised outer edges, Wherein the pellet adapter is removably positionable on a fuel grate of a furnace within a combustion chamber of the furnace.

13. The pellet adapter of claim 12, wherein the pellet adapter further comprises a plurality of wells formed in the pellet tray.

14. The pellet adapter of claim 13, wherein the recess includes feet that contact the fuel grate when the pellet adapter is positioned on the fuel grate within the combustion chamber.

15. The particle adapter of claim 12, wherein the central raised portion includes a lower portion fixedly attached to the particle tray and an upper portion removably attached to the lower portion.

16. The particle adapter of claim 12, wherein at least one of the central ridge or the raised outer edge includes a plurality of third ventilation holes sized and shaped to prevent passage of fuel particles.

17. The particle adapter of claim 12, wherein the central raised portion comprises a truncated cone.

18. The particle adapter of claim 12, wherein the particle tray comprises a truncated cone.

19. The pellet adapter of claim 12, wherein when the pellet adapter is positioned on a fuel grate within a combustion chamber, an air gap exists between the raised outer edge and an inner wall of the combustion chamber, and a bottom edge of the raised outer edge contacts the fuel grate.

20. A pellet adapter for adapting a log or stick burning stove to a pellet burning stove, the log or stick burning stove comprising a combustion chamber having a fuel grate therein, the fuel grate having holes for passage of air or embers, the holes having a first width that does not inhibit or prevent passage of fuel pellets, the pellet adapter comprising: a particle tray sized to be removably mounted within the combustion chamber and including a plurality of vents having a second width less than the first width, the second width sized to inhibit or prevent passage of fuel particles; as well as A handle is provided on the pellet tray, the handle being graspable by a user to place or remove the pellet tray into or from the combustion chamber, thereby adapting the stove into a pellet burning stove.

21. The particle adapter of claim 20, comprising: a raised outer edge surrounding the particle tray and having a first height; as well as A central raised portion extends from the particle tray and has a second height greater than the first height.

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

23. The pellet adapter of claim 20, wherein the pellet adapter further comprises a plurality of dimples formed in the pellet tray, the dimples forming legs that offset the pellet tray from the fuel grate.

24. A method of adapting a log or stick burning stove to a pellet burning stove, the log or stick burning stove comprising a combustion chamber having a fuel grate therein, the fuel grate having apertures configured to allow air or embers to pass therethrough, the apertures having a first width that does not inhibit or prevent the passage of fuel particles, the method comprising: grasping a pellet adapter by a handle, the pellet adapter being sized to fit within a combustion chamber and having a pellet tray including a plurality of vents having a second width less than the first width, the second width being sized to inhibit or prevent passage of fuel pellets; Introducing a pellet adapter into the top opening of a combustion chamber of a log or stick burning stove; as well as Add fuel pellets to the pellet tray for burning.

25. The method of claim 24, wherein introducing the pellet adapter into the top opening of the combustion chamber comprises placing the pellet adapter onto the fuel grate, the pellet adapter offset from the fuel grate to allow air to flow between the fuel grate and the pellet adapter.

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