US20240377067A1

US20240377067A1 - Fire pit with lift off ash handling mechanism

Info

Publication number: US20240377067A1
Application number: US18/658,108
Authority: US
Inventors: Lucas Henry Zeitler
Original assignee: Lamplight Farms Inc
Current assignee: Lamplight Farms Inc
Priority date: 2023-05-08
Filing date: 2024-05-08
Publication date: 2024-11-14

Abstract

A fire pit includes an upper portion having an inner chamber wall defining a combustion chamber with a fuel grate retained therein, and a lower portion having a base member defining an ash receptacle. The upper and lower portions separably mate together such that ash falling through the fuel grate is received in the ash receptacle when the upper and lower portions are fitted together.

Description

CROSS-REFERENCE TO RELATED CASES

This application claims the benefit of U.S. provisional patent application Ser. No. 63/464,759, filed on May 8, 2024, and incorporates such provisional application by reference into this disclosure as if fully set out at this point.

FIELD OF THE INVENTION

This disclosure relates to fire pits in general and, more specifically, to non-gas-burning fire pits.

BACKGROUND OF THE INVENTION

Outdoor fire pits have, in the past, been permanent fixtures built from rock, concrete, metals, or other resilient and heavy materials. Often the fire pit is built directly on the ground and is not readily portable. Other fire pits have been developed that may be somewhat portable. However, in an effort to contain fire and ash combustion properties are less than desirable. Smoky fires, possibly with little light or radiated heat, have been the result. Additionally, fire pits produce combustion byproducts, such as ash, that must be removed from the firepit and disposed.
What is needed is a system, device, and method for addressing the above, and related, concerns.

SUMMARY OF THE INVENTION

The invention of the present disclosure, in one aspect thereof, comprises a fire pit including an upper portion having an inner chamber wall defining a combustion chamber with a fuel grate retained therein, and a lower portion having a base member defining an ash receptacle. The upper and lower portions separably mate together such that ash falling through the fuel grate is received in the ash receptacle when the upper and lower portions are fitted together.
In some embodiments, the fuel grate comprises a central conic portion. The central conic portion may be surrounded by a flat surround. The central conic portion may comprise a perforated panel. The lower portion may comprise a floor inside a funnel section defining the ash receptacle.
In some cases, the inner wall is frustoconical and a circumference of an upper end of the funnel section is equal to a circumference of a lower end of the inner wall. The lower portion may comprise a support surface affixed to the upper end of the funnel section, the support surface supporting the inner wall when the upper portion is mated to the lower portion. The lower portion may comprises a base wall affixed to the support surface and circumscribing the lower end of the inner wall when the upper portion is mated to the lower portion. In some cases, a spacer interposes the lower end of the inner wall and the base wall when the upper portion is mated to the lower portion.
Some embodiments include an outer chamber wall spaced apart from and circumscribing the inner chamber wall to define an airflow space. The inner chamber wall may define a first plurality of apertures below a level of the fuel grate and a second plurality of apertures proximate an upper end of the inner chamber wall. A top ring may interpose the inner chamber wall and the outer chamber wall above the first plurality of apertures. Some embodiments further comprise a rim at a top of the inner chamber wall above the top ring. The fire pit may include a plurality of handles on the outer chamber wall. In some cases, the outer chamber wall defines the plurality of handles.
The invention of the present disclosure, in another aspect thereof, comprises a fire pit having an upper portion including an inner chamber wall defining a combustion chamber and an outer chamber wall spaced apart from the inner chamber wall to define an air flow space between the inner chamber wall and outer chamber wall, a first plurality of apertures defined in the inner chamber wall proximate a top thereof, a second plurality of apertures defined in the inner chamber wall below a fuel grate contained therein, a lower portion having a lower base member that supports the upper portion when the upper portion is fitted to the lower portion, and an ash receptacle defined by the lower base member that receives ashes that fall through the fuel grate.
In some embodiments, the lower base member comprises a floor surrounded by a funnel section directing ashes toward the floor. A support surface may surround the funnel section with the support surface supporting the upper portion when the upper portion is fitted to the lower portion.
The invention of the present disclosure, in another aspect thereof, comprises a fire pit having an inner chamber wall defining a combustion chamber, the inner chamber wall defining a first plurality of air apertures proximate an upper end thereof and a second plurality of air apertures proximate a lower end thereof, a fuel grate supported in the inner chamber wall at a level between the first plurality of apertures and the second plurality of apertures, and a base member having a supporting surface that supports the inner chamber wall and defining an ash receptacle below the fuel grate. The fuel grate defines a conic portion that is elevated toward a center thereof.
The fire pit may also include an outer chamber wall spaced apart from the inner chamber wall by a plurality of wall supports interposing the outer chamber wall and inner chamber wall, wherein the outer chamber wall defines a plurality of handle openings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side perspective view of a fire pit according to aspects of the present disclosure.

FIG. 2 is a side view of the fire pit of FIG. 1 .

FIG. 3 is a top view of the fire pit of FIG. 1 .

FIG. 4 is an exploded perspective view of the fire pit of FIG. 1 .

FIG. 5 is a side perspective cutaway view of the fire pit of FIG. 1 .

FIG. 6 is a side cutaway view of the fire pit of FIG. 1 illustrating exemplary air flow through the device in operation.

FIG. 7 is a side cutaway view of another fire pit according to aspects of the present disclosure.

FIG. 8 is an elevation view of the fire pit of FIG. 7 .

FIG. 9 is a perspective view of the fire pit of FIG. 7 in an open configuration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIGS. 1-6 , a fire pit 500 can be seen. FIG. 1 is a perspective view of the fire pit 500, while FIG. 2 is a side elevation view, FIG. 3 is a top view, and FIG. 4 is an exploded view, FIG. 5 is a cut-away perspective view, and FIG. 6 is a cut-away elevation view.
The fire pit 500 may be configured to burn wood pellets, whole sticks of wood, charcoal, or another suitable solid fuel. The fire pit 500 provides an inner chamber 102 bound by an inner chamber wall 104. In various embodiments, the inner chamber 102 is frustoconical in shape and may taper from a relatively wider base to a relatively narrower upper end. Various structures and components of the fire pit 500, including the inner chamber wall 104, may comprise stainless steel or another suitably heat resistant material. The inner chamber wall 104 may be uninsulated and/or of a single layer or thickness. The inner chamber wall 104 is intended to radiate heat from an internal fire outward and away from the fire pit 500 to be enjoyed by a user of the fire pit 500. In some embodiments, the inner chamber wall 104 may form what is considered an engine of the fire pit 500.
The inner chamber 102 may have a fuel support grate 106 at or near a bottom end thereof. The grate 106 supports burning fuel and may allow ash to fall therethrough. Combustion air may be provided upwardly through the grate 106. The inner chamber 102 may rest upon or attach to a base 108, that may be pan-shaped to retain ash from the fuel support grate 106. The base 108 may have a pan 110 with a perimeter affixed to an upright, possibly cylindrical portion 112 supporting the inner chamber wall 104. Air intake openings 114 may be provided in the upright portion 112 for feeding combustion air to the fuel support grate 106. In some embodiments, the inner chamber wall 104 is separable from the base 108 to facilitate emptying of ashes and other cleaning tasks.
In operation, as fuel is combusted on the fuel support grate 106, heated gases rise through the inner chamber 102 and out through a top opening 116 in the upper narrower portion of the inner chamber 102. Gases rising from the fuel on the fuel support grate 106 may not be completely combusted and performance of the fire pit 500 may be altered by providing additional air into the inner chamber 102. In various embodiments, a number of outer chambers 118 may be configured to provide additional air that may be drawn along the outside of the inner chamber wall 104. The inner chamber wall 104 may provide heating of air drawn into the outer chambers 118 thereby promoting rapid combustion inside the inner chamber 102 when the air drawn in through the secondary chambers 118 reaches incompletely combusted gases within the inner chamber 102.
In the present embodiment, there are eight secondary chambers 118 spaced roughly equidistantly around the inner chamber wall 104. However, more or fewer secondary chambers 118 may be utilized. In various embodiments, the secondary chambers 118 may cover less than half of the total outer surface area of the inner chamber wall 104. In this way, a user may experience an adequate level of radiated or infrared heat from the inner chamber wall 104, while a sufficient amount of heat is also transferred to the air inside the secondary chambers 118 to promote rapid combustion upon entering the inner chamber 102.
An upper manifold 120 may be provided at or near the top of the inner chamber 102. The manifold accepts incoming heated air from the secondary chambers 118 that may be expelled via a plurality of inward facing apertures 122. The apertures 122 provide “jets” of heated combustion-promoting air to the hot and incompletely combusted gases rising from the fuel on the fuel support grate 106. This additional air promotes further combustion of the gases resulting in an increase in visible flames and heat, and a decrease in smoke resulting from otherwise incomplete combustion.
Various embodiments of the present disclosure discuss and describe apertures, slots, spaces, and/or discrete openings defined in various surfaces or walls to allow or promote the flow of combustion air (primary or secondary). It should be understood that in other embodiments, grids, meshes, screens, or other air permeable materials or structures may also be used to admit necessary or desirable air flow. Unless otherwise defined more specifically, an air flow region through a structure should be taken to mean apertures, slots, spaces, and other discrete openings, or grids, meshes, screens, or other air permeable materials providing adequate air flow, passage, or permeability for the stated structure or function.
Referring now to FIG. 1 , a side perspective view of an embodiment of a fire pit 500 according to aspects of the present disclosure is shown. FIG. 2 is a side view of the fire pit 500, while 3 is a top view, FIG. 4 is an exploded perspective view, and FIG. 5 is a side perspective cutaway view of the fire pit 500. FIGS. 1-5 , taken together, may best illustrate the structure features of the fire pit 500.
The fire pit 500 comprises an inner chamber wall 104 defining an inner chamber 102. A fuel grate 502 is supported within the inner chamber 102 that is located medially between a top and bottom of the inner chamber wall 104, though in some embodiments it is nearer the bottom, as shown. The fuel grate 502 provides support for solid fuels to be burned in the fire pit 500. Being located or attached nearer the bottom of the inner chamber wall 104 means combustion takes place mostly within the inner chamber 102 and provides ample opportunity for radiative heating from the fire pit 500 without direct exposure to flame.
As best seen in FIG. 5 , the fuel grate 502 is perforated to allow combustion air to flow therethrough, and as well as allowing ashes or spent fuel to fall through the fuel grate 502. The fuel grate 502 may be planar, generally planar, or flat with openings or perforations spread substantially evenly thereacross such that the entire fuel bed may be supplied with air as well as drained of ash or other debris. The fuel grate 502 may be round or generally round to mate with or affix to the circular inner chamber wall 104.
In some embodiments, the fuel grate 502 may be divided into an outer area 524 surrounding an inner area 526. The inner area 526 may be circular and the outer area 524 may be annular. In other embodiments the inner area 526 and outer area 524 have other cooperating shapes. Between the inner area 526 and outer area 524 may be a support ring 528. In the present embodiment, the support ring 528 is a short, sloped wall interposing the inner area 526 and outer area 524. It should be understood that the support ring 528, inner area 526, and outer area 524 may be separate regions of a contiguous fuel grate 502. The fuel grate 502 components may be formed as a monolithic whole (e.g., by machining or stamping) or may be fitted together after separate manufacture (e.g., by welding).
The support ring 528, in the present embodiment, locates a center deflector 504 that sits over the inner area 526 of the fuel support. The deflector 504 may be in configured as a cone that provides an outwardly sloping wall that tends to cause fuel placed into the inner chamber 102 to move toward the outer portion of the inner chamber 102, near the inner chamber wall 104. Thus, more combustion may take place near the inner chamber wall 104 to improve radiant heat transfer as well as the performance of the air flow mechanisms of the fire pit 500 discussed below.
The fire pit 500 may also be operated without the deflector 504, though the burn characteristics may change. A loop 506 may be provided for ease of removal of the deflector 504 by hand (if cool) or using a poker or other fire tool. The inner area 526 of the fuel grate 502 may be perforated similarly to the outer area 524. This may serve to aid in combustion if the fire pit 500 is operated without the deflector 504 and/or to facilitate ash removal or cleaning. It should be understood that the deflector 504, operating to urge fuel away from the center area 526 could comprise shapes different from that of a cone (although, in various embodiments, it would be advantageous to retain sloping walls or a similar feature). However, a cone-shaped deflector 504 in cooperation with a circular support ring 528 may be concentric to the outer area 524 of the fuel grate 502 as well as the inner chamber wall 104, thus promoting even burning and radiant heating all the way around the fire pit 500.
The inner chamber wall 104 may be frustoconical in shape, and narrower at the top than the bottom. It may define a plurality of primary air intakes or apertures 508 near the bottom thereof. The fuel grate 502 may be situated superior to, or above, these primary air intakes 508. Air entering these intakes 508 may ultimately provide initial combustion air to fuel on the fuel grate 502 as explained further below. Nearer the top of the inner chamber wall (in some embodiments, just below a top edge) are the apertures 122, which serve here as secondary air intakes. Air entering through these holes or apertures 122 may be heated by passing near an outside of the inner chamber wall 104 and provide additional oxygen for combusting unburned and possibly already heated combustibles (mostly in gaseous form) rising near the top of the inner chamber 102 from the fire below on the fuel grate 502.
Immediately outside the inner chamber wall 104 (where heating of secondary air occurs) may be a surrounding intake chamber 514. The intake chamber 514 serves as a manifold for air coming from outside the fire pit 500 and into the inner chamber 102 via apertures 508 and apertures 122. The intake chamber 514 may also be considered a heating chamber since this is where combustion air is primarily heated during operation of the fire pit 500.
The intake chamber 514 may be bounded on the outside by an outer wall 510. The outer wall 510 may be frustoconical but larger at a bottom thereof than a top. Thus, the outer wall 510 may be relatively close to, and possibly touching or connected to, the inner chamber wall 104 at or near the bottom of both of these. Toward the top of both the inner chamber wall 104 and the outer wall 510 these two components may be spaced apart. A top panel may close or cover the space between the inner chamber wall 104 and the outer wall 510 near or on the top of these. As can be seen in FIG. 5 , for example, this may lend a triangular cross section to the intake chamber 514. The intake chamber 514 may generally define an anulus concentric with the inner chamber 102, which may provide even heating all around the fire pit 500.
In order to admit air from outside the fire pit 500, the outer wall 510 may have a slatted configuration. The outer wall 510 may comprise a number of spaced apart slats 516. Spacing between the slats 516 may vary but in some embodiments spacing between each set of adjacent slats 516 is the same or substantially the same. Little spacing may be needed to admit sufficient air and it may be advantageous to space the slats fairly close together to improve heating of air in the intake chamber 102. As with other components of the fire pit 500 the slats may comprise a metal to promote even and adequate radiant heating outside the fire pit. In some embodiments, rather than discrete slats 516, the wall 510 may comprise one or more sections with openings cut or defined therein replicating the functionality of the slatted configuration.
As may be best seen in FIG. 4 , each slat 516 may not define a complete circle around the inner chamber wall 104, but may represent only a portion of a circle arc. In some embodiment, each slat (e.g., at each level) may be broken into three arcs. A wall frame 518 may provide a top ring 520 from which descends one or more support members 522. The slats 516 may affix to these support members 522, which may be equidistantly spaced from one another around the top ring 520. In the illustrated configuration, the slats 516 run horizontally or generally horizontally. Thus, air is supplied into the intake chamber 514 in a substantially concentric manner to the inner chamber wall 104. The support members 522, at least where their number is limited (e.g., here to three) do not substantially interfere with even air flow or heating. In other embodiments, a series of vertical slats may be used. In further embodiments, the outer wall 510 may be a solid component that has had openings (vertical or horizontal) cast into it (or milled, cut, or punched therefrom).
The intake chamber 514, the inner chamber 102, and the components defining those parts, may sit atop or affix to a base 530. The base 530 may support the intake chamber 514 and inner chamber 102 above the ground and provide ash handling capabilities. The base 530 may comprise a floor 532 affixed to a surrounding outer wall 534. Over the floor 532 and below the fuel support grate 502 a funnel 536 may be provided with a central opening 538. The funnel 536 urges ash and debris from combustion toward the center of the floor 532.
An opening 540 (FIG. 4 ) may be defined in the wall 534 for accepting a removable ash pan 542 situated below the opening 538 of the funnel 536. A heat resistant handle 544 (comprising, e.g., wood or plastic) may affix to the ash pan 542 for removal and insertion of the ash pan 542.
The base 530 may also be fitted with a stand 546 (FIG. 5 ). The stand 546 may comprise a support ring 548 which may receive the base 530 as well as locate legs 550. Three legs 550 are shown but more or fewer (depending on their shape) could be utilized. As can be seen in FIG. 9 , the support ring 548 of the stand 546 may fit into a lip 560 on the wall 534 of the base 530. The outer wall 510 and the inner chamber wall 104 may each also affix to this lip 560 or another nearby location.
As discussed above, the outer wall 510 may provide a wall frame 518 having a top ring 520. This may serve as a point to which the top panel 512 affixes to span the space between the outer wall 510 and the inner chamber wall 104 (in other embodiments the top panel 512 may attach elsewhere, e.g., to a top slat 516). A chamber top ring 515 may join the top panel 512 to the top of the inner chamber wall 104, or these components may join without a fastener (e.g., by folding together) or by welding. In any event, the top panel 512 is securely fixed to retain the outer wall 510 in a spaced apart relationship from the inner chamber wall 104. The top panel 512 also, therefore, partially defines the intake chamber 514 and prevents air from escaping.
Referring now to FIG. 6 , a side cutaway view of the fire pit 500 of FIG. 1 illustrating exemplary air flow through the device in operation is shown. Air can be seen to enter into the intake chamber 514 from outside the fire pit 500 via spaces 552 between adjacent slats 516 and space 554 between the top of the slats 516 and the top panel 512. Some air from the intake chamber 514 (particularly from spaces between some of the lower of the slats 516) is drawn through primary air intake apertures 508 and to and through the fuel grate 502. As shown, this air will particularly flow to and through the outer area 524 of the fuel grate 502 if the deflector 504 is in place. If the deflector 504 is not in place, air flows to and through the inner area 526 more readily as well. Air entering the inner chamber 102 via primary air intakes 508 may not be particularly heated.
Air entering the intake chamber 514 may also flow up along the inner chamber wall 104, which may have a relatively high temperature owing to the fire operating inside the inner chamber 102 (and particularly on or near the outer area 524 of the fuel grate 502). Such air will become heated via radiant and convective heating. The heated air rises to the apertures 508 where it enters the inner chamber 102 near the top thereof. As discussed above, gases coming from the combusting fuel on the fuel grate 502 generally include unburned flammables. Limited oxygenation from the primary combustion air (even where primary combustion air flow is not restricted) is one cause of the unburned flammables. In some cases, injection of secondary air does little to promote further consumption of these unburned flammables because of the relatively low temperature of the ambient air. Here, however, the secondary combustion air is heated within the intake chamber 514 and is more useful for further burning of the unspent fuel. This secondary burning provides additional heating as well as a reduction in smoke.
From the view of FIG. 6 , it can also be seen that the floor 532 of the base 530 may provide a support 556 for receiving the ash pan 542 and supporting it in the best location below the funnel 536 (e.g., under the opening 538 shown in FIG. 5 ).
Dimensions of the fire pit 500 may vary. However, in one embodiment the height of the fire pit, including the legs 550, is about 19.3 inches. Exclusive of the legs 550, the height may be about 14.9 inches. A total diameter of the fire pit 500 may be about 24.6 inches. Thus, the fire pit 500 may be conveniently sized to provide a usable fire, yet small enough to be moved.
Referring now to FIG. 7 a side cutaway view of another fire pit 600 according to aspects of the present disclosure is shown. The fire pit 600 comprises an upper portion 610 having an inner chamber wall 620 defining an inner chamber 621. The inner chamber 621 serves as a combustion chamber for solid fuels.
The inner chamber wall 620 has an upper end 622 and lower end 624. The inner chamber 620 wall may define a frustoconical combustion chamber or inner chamber 621. The upper end 622 and lower end 624 may terminate in circular openings, with the upper end 622 having a smaller diameter than the lower end 624. In other embodiments, the inner chamber wall 621 may be cylindrical or have another geometry. The upper end 622 may provide for filling the chamber 621 with solid fuel. The lower end 624 may interface with an ash handling system as further described below.
The inner chamber wall 620 may define a plurality of upper apertures 626 that are proximate to upper end 622. Similar to previous embodiments, the apertures 626 provide “jets” of heated combustion-promoting air to the hot and incompletely combusted gases rising from the solid fuel. This additional air promotes further combustion of the gases resulting in an increase in visible flames and heat, and a decrease in smoke resulting from otherwise incomplete combustion.
The inner chamber wall 620 may define a plurality of lower apertures 628 that are proximate to lower end 624. The inner chamber wall 620 may support a fuel grate 629 near to, but at least slightly above, the lower apertures 628. The fuel grate may define a plurality of fuel grate apertures 632. Primary combustion air may enter the combustion chamber 621 through the apertures 628 and then through apertures 632 to fuel combusting or burning on the fuel grate 629.
The fuel grate apertures 632 of fuel grate 629 may be sized to permit ash to pass through and into a base member 670 for handling and disposal. The grate 629 may comprise a flat, possibly annular, surround 631 connected to and circumscribing a central conic portion 630. Apertures 632 may be defined in the conic portion 630 and/or the surround 631. In some embodiments, the grate 629 is substantially completely flat (e.g., no conic portion is present).
When present, the conic portion 630 tends to cause fuel placed into the inner chamber 621 to move toward an outer portion of the inner chamber 621 (e.g., toward the surround 631), near the inner chamber wall 620. Thus, more combustion may take place near the inner chamber wall 620 to improve radiant heat transfer as well as the performance of the air flow mechanisms of the fire pit 600.
While the fuel grate 629 is illustrated as being formed of a perforated wall (or a shaped sheet or panel), the fuel grate 629 could be formed of a wire mesh material of suitable strength and resiliency. The fuel grate 629 could also be formed of cast iron or similar grate. However, the illustrated embodiment, where the fuel grate 629 is formed of a shaped panel of material with defined apertures may allow for greater fine tuning of air flow and ash management through the fuel grate 629. The apertures 632 are not necessary equidistantly spaced from one another, nor do they necessarily have the same density (or create the same amount of open space for air and/or ash) although such an embodiment is contemplated as well. Similarly, the apertures 632 may or may not all be of the same size or diameter. Apertures 632 may be circular (e.g., an efficient shape) or have other shapes.
The fuel grate 629 may be affixed to the interior wall 620. The surround 631 or another horizontal portion may provide a connection or fixation point(s) for the fuel grate 629. Some embodiments provide a skirt 633 descending downwardly from the periphery of the fuel grate 629 (e.g., from the surround 631) that may be fastened or otherwise affixed to the interior wall 620. The skirt 633 may or may not be fixed to the fuel grate 629 (e.g., it may act as a supporting member for the fuel grate that may wedge it into position against the interior wall 620).
The base member 670 provides for an ash collection location. The base member 670 may define an ash receptacle 702. The base member 670 may comprise a floor 672 surrounded by a sloped wall or funnel section 676. The funnel section 676 may have a lower end that joins to a perimeter of the floor 672. In the illustrated embodiment, the floor 672 and the funnel section 676 comprise the ash receptacle. The floor 672 may be flat or may be concave or dished for additional ash capacity. In other embodiments, the base member 670 may combine the floor 672 and funnel section 676 into a single concave or dished ash receptacle. One or more legs 690 may be attached to the base member 670 to elevate the base member 670.
Upper portion 610 may additionally comprise an outer chamber wall 640 that surrounds inner chamber wall 620. The outer chamber wall 640 may be frustoconical with a similar angle or inward slope as the inner chamber wall 620, but with a larger circumference at each corresponding elevation. The outer chamber wall 640 may comprise an upper portion 641 and a lower portion 642, with the upper portion having a smaller circumference than the lower portion 642.
A plurality of chamber wall supports 650 may separate the outer chamber wall 640 from inner the chamber wall 620, while also joining the outer chamber wall 640 to the inner chamber wall 620. Thus an airflow space 651 is defined between the outer chamber wall 640 and the inner chamber wall 620. The wall supports 650 (only one is in frame) may each comprise an inner portion 650′ and an outer portion 650″ joined to the inner chamber wall 620 and outer chamber wall 640, respectively. The inner portion 650′ and outer portion 650″ may extend toward one another and be joined or fastened together
Combustion air may enter the airflow space 651 adjacent lower end 642 of outer chamber wall 640 and also adjacent to lower end 624 of inner chamber wall 620. Airflow passes through lower apertures 628 through fuel grate apertures 632. Airflow also through upper apertures 626 of inner chamber wall 620 providing secondary air. Additionally, the secondary air flowing into upper apertures 626 from the airflow space 651 may be warmed by passing adjacent the chamber inner wall 620 for increased performance (e.g., it will tend to provide oxygen with less lowering of the flame temperature near the top of the combustion chamber 621).
Space between the inner chamber wall 620 and the outer chamber wall 640 may be capped or covered by a top ring 643 at or near the upper end 641 of the outer chamber wall 640 and the upper end 622 of the inner chamber wall 620. Upper end 622 of inner chamber wall 620 may be slightly above the upper end 641 of the outer chamber wall 640 and the top ring 643. The upper end 641 may be rolled or folded inward to form a rim 627 or otherwise have a rim attached thereto. The rim 627 may be useful for locating or stabilizing covers or other accessories on or at the top of the fire pit 600.
Referring now to FIG. 8 an elevation view of the fire pit 600 of FIG. 7 is shown. Handles 644 may be provided on outer chamber wall 640 of upper portion 610 to facilitate easy separation and removal of upper portion 610 from base member 670 for ash disposal. In some embodiments, handles 644 comprise openings 646 formed in outer wall 640. Two or more openings 646 or handles 644 may provided (e.g., on opposite sides of the fire pit 600). Openings 646 may be rounded or radiused for comfort. In other embodiments, handles 644 comprise hand holds affixed to the outer surface of the outer chamber wall 640.
Legs 690 may be formed of bent tubular members attached at two locations to support surface 678 surrounding and affixed to the funnel section 676. Ascending from an attached to support surface 678 is an outer base wall 680 that may be partially or completely overlapped by the outer chamber wall 640 when the upper portion 610 is fitted to the lower portion 660.
Referring now to FIG. 9 a perspective view of the fire pit 600 of FIG. 7 in an open or separated configuration is shown. In FIG. 9 the upper portion 610 has been lifted free of the lower section 660 such as would occur when the fire pit is not in use and ashes are to be disposed of that have collected in the base member 670. Here it can also be seen how the support surface 678 adjoins and circumscribes the funnel section 676 (or the combined funnel section 676 and floor 672). In some embodiments, the support surface 678 is generally flat and may be level or approximately level with the ground or other support surface below when supported by legs 690.
The support surface 678 may be circumscribed by the outer base wall 680 having an upper rim 681. When the upper portion 610 is fitted to the lower portion 660 (e.g., when the fire pit 600 is operational) the support surface 678 may support the lower end 624 of the inner chamber wall 620. The outer base wall 680 then circumscribes the lower end 624 of the inner chamber wall 620.
In some embodiments, the lower end 624 of the inner chamber wall 620 is affixed to and circumscribed by a spacer 701 (FIG. 7 ) that then interposes the lower end 624 of the inner chamber wall and the base wall 680. The spacer 701 may then be supported directly or indirectly by the support surface 678. The spacer 701 may have a horizontal width matching or approximately matching a width of the support surface 678 such that the lower end 624 of the inner chamber wall 620 is centered over the funnel section 676 and floor 672. The lower end 624 may have a circumference matching or approximately matching an upper circumference of the funnel section 676 such that all or substantially all ash falling from the fuel grate 629 is captured into the funnel section 676 and/or floor 672.
The circumference of the outer chamber wall 640 at the lower end 642 may exceed the circumference of the outer base wall sufficiently such that air may flow into the air flow space 651 when the upper portion 610 is fitted to the lower portion 660 as described.
In the present disclosure, fire pits having a generally circular and generally horizontal cross section are shown and described. For example, fire pits, 500, 600 may be considered generally circular while other embodiments of fire pits may be generally rectilinear. Some advantages may be observed with both circular and rectilinear embodiments. However, further embodiments having additional internal or external geometries are contemplated within the present disclosure. For example, a fire pit may have an arbitrary number of sides and the sides may be of equal or unequal length. Additionally, various non-linearities and curvatures may be presented. Unless the language of an appended claim requires a specific geometry, shape, number of sides, etc., functionally equivalent variations are intended to be within the scope of the claimed invention.
It is to be understood that the terms “including”, “comprising”, “consisting” and grammatical variants thereof do not preclude the addition of one or more components, features, steps, or integers or groups thereof and that the terms are to be construed as specifying components, features, steps or integers.
If the specification or claims refer to “an additional” element, that does not preclude there being more than one of the additional element.
It is to be understood that where the claims or specification refer to “a” or “an” element, such reference is not be construed that there is only one of that element.
It is to be understood that where the specification states that a component, feature, structure, or characteristic “may”, “might”, “can” or “could” be included, that particular component, feature, structure, or characteristic is not required to be included.
Where applicable, although state diagrams, flow diagrams or both may be used to describe embodiments, the invention is not limited to those diagrams or to the corresponding descriptions. For example, flow need not move through each illustrated box or state, or in exactly the same order as illustrated and described.
Methods of the present invention may be implemented by performing or completing manually, automatically, or a combination thereof, selected steps or tasks.
The term “method” may refer to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the art to which the invention belongs.
The term “at least” followed by a number is used herein to denote the start of a range beginning with that number (which may be a range having an upper limit or no upper limit, depending on the variable being defined). For example, “at least 1” means 1 or more than 1. The term “at most” followed by a number is used herein to denote the end of a range ending with that number (which may be a range having 1 or 0 as its lower limit, or a range having no lower limit, depending upon the variable being defined). For example, “at most 4” means 4 or less than 4, and “at most 40%” means 40% or less than 40%.
When, in this document, a range is given as “(a first number) to (a second number)” or “(a first number)-(a second number)”, this means a range whose lower limit is the first number and whose upper limit is the second number. For example, 25 to 100 should be interpreted to mean a range whose lower limit is 25 and whose upper limit is 100. Additionally, it should be noted that where a range is given, every possible subrange or interval within that range is also specifically intended unless the context indicates to the contrary. For example, if the specification indicates a range of 25 to 100 such range is also intended to include subranges such as 26-100, 27-100, etc., 25-99, 25-98, etc., as well as any other possible combination of lower and upper values within the stated range, e.g., 33-47, 60-97, 41-45, 28-96, etc. Note that integer range values have been used in this paragraph for purposes of illustration only and decimal and fractional values (e.g., 46.7-91.3) should also be understood to be intended as possible subrange endpoints unless specifically excluded.
It should be noted that where reference is made herein to a method comprising two or more defined steps, the defined steps can be carried out in any order or simultaneously (except where context excludes that possibility), and the method can also include one or more other steps which are carried out before any of the defined steps, between two of the defined steps, or after all of the defined steps (except where context excludes that possibility).
Further, it should be noted that terms of approximation (e.g., “about”, “substantially”, “approximately”, etc.) are to be interpreted according to their ordinary and customary meanings as used in the associated art unless indicated otherwise herein. Absent a specific definition within this disclosure, and absent ordinary and customary usage in the associated art, such terms should be interpreted to be plus or minus 10% of the base value.
Thus, the present invention is well adapted to carry out the objects and attain the ends and advantages mentioned above as well as those inherent therein. While the inventive device has been described and illustrated herein by reference to certain preferred embodiments in relation to the drawings attached thereto, various changes and further modifications, apart from those shown or suggested herein, may be made therein by those of ordinary skill in the art, without departing from the spirit of the inventive concept the scope of which is to be determined by the following claims.

Claims

What is claimed is:

1. A fire pit comprising:

an upper portion having an inner chamber wall defining a combustion chamber with a fuel grate retained therein; and

a lower portion having a base member defining an ash receptacle;

wherein the upper and lower portions separably mate together such that ash falling through the fuel grate is received in the ash receptacle when the upper and lower portions are fitted together.

2. The fire pit of claim 1, wherein the fuel grate comprises a central conic portion.

3. The fire pit of claim 2, wherein the central conic portion is surrounded by a flat surround.

4. Th fire pit of claim 2, wherein the central conic portion comprises a perforated panel.

5. The fire pit of claim 1, wherein the lower portion comprises a floor inside a funnel section defining the ash receptacle.

6. The fire pit of claim 5, wherein:

the inner wall is frustoconical; and

a circumference of an upper end of the funnel section is equal to a circumference of a lower end of the inner wall.

7. The fire pit of claim 6, wherein the lower portion comprises a support surface affixed to the upper end of the funnel section, the support surface supporting the inner wall when the upper portion is mated to the lower portion.

8. The fire pit of claim 7, wherein the lower portion comprises a base wall affixed to the support surface and circumscribing the lower end of the inner wall when the upper portion is mated to the lower portion.

9. The fire pit of claim 8, further comprising a spacer interposing the lower end of the inner wall and the base wall when the upper portion is mated to the lower portion.

10. The fire pit of claim 1, further comprising an outer chamber wall spaced apart from and circumscribing the inner chamber wall to define an airflow space.

11. The fire pit of claim 10, wherein the inner chamber wall defines a first plurality of apertures below a level of the fuel grate and a second plurality of apertures proximate an upper end of the inner chamber wall.

12. The fire pit of claim 11, further comprising a top ring interposing the inner chamber wall and the outer chamber wall above the first plurality of apertures.

13. The fire pit of claim 12, further comprising a rim at a top of the inner chamber wall above the top ring.

14. The fire pit of claim 12, further comprising a plurality of handles on the outer chamber wall.

15. The fire pit of claim 14 wherein openings in the outer chamber wall defines the plurality of handles.

16. A fire pit comprising:

an upper portion including an inner chamber wall defining a combustion chamber and an outer chamber wall spaced apart from the inner chamber wall to define an air flow space between the inner chamber wall and outer chamber wall;

a first plurality of apertures defined in the inner chamber wall proximate a top thereof;

a second plurality of apertures defined in the inner chamber wall below a fuel grate contained therein;

a lower portion having a lower base member that supports the upper portion when the upper portion is fitted to the lower portion; and

an ash receptacle defined by the lower base member that receives ashes that fall through the fuel grate.

17. The fire pit of claim 16, wherein the lower base member comprises a floor surrounded by a funnel section directing ashes toward the floor.

18. The fire pit of claim 17, further comprising a support surface surrounding the funnel section, the support surface supporting the upper portion when the upper portion is fitted to the lower portion.

19. A fire pit comprising:

an inner chamber wall defining a combustion chamber, the inner chamber wall defining a first plurality of air apertures proximate an upper end thereof and a second plurality of air apertures proximate a lower end thereof;

a fuel grate supported in the inner chamber wall at a level between the first plurality of apertures and the second plurality of apertures; and

a base member having a supporting surface that supports the inner chamber wall and defining an ash receptacle below the fuel grate;

wherein the fuel grate defines a conic portion that is elevated toward a center thereof.

20. The fire pit of claim 19, further comprising:

an outer chamber wall spaced apart from the inner chamber wall by a plurality of wall supports interposing the outer chamber wall and inner chamber wall;

wherein the outer chamber wall defines a plurality of handle openings.