US20060236996A1

US20060236996A1 - Fire pit

Info

Publication number: US20060236996A1
Application number: US11/279,949
Authority: US
Inventors: Robert Mosher; Paul Grimes
Original assignee: Coleman Co Inc
Current assignee: Coleman Co Inc
Priority date: 2005-04-22
Filing date: 2006-04-17
Publication date: 2006-10-26
Also published as: CN1854605A; CA2544071A1

Abstract

A fire pit that is fueled by one or more small, disposable propane cylinders. In an embodiment, the small, disposable cylinder is directly connected to the fire pit without a hose. The fire pit includes a pilot light having a fuel feed and an air feed. The fuel feed is provided by a conduit that leads to an electrode for the pilot light. The air feed is provided by a perforated tube that extends around the electrode.

Description

REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional patent application Ser. No. 60/673,987, filed Apr. 22, 2005, and incorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention is related to fuel burning devices, and more particularly to a fuel-powered fire pit.

BACKGROUND OF THE INVENTION

There have been a number of backyard fireplaces known in the art, from large wood-burning units to small copper pots fueled by real wood or twenty (20) pound propane cylinders. It is also possible to fuel such devices with DURAFLAME logs or other synthetic self-contained fuel sources. Many of these fire pits are decorative in nature and feature copper bowls, stainless steel bowls, granite rings around such bowls, and other aesthetic enhancements.

SUMMARY OF THE INVENTION

The following presents a simplified summary of some embodiments of the invention in order to provide a basic understanding of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some embodiments of the invention in a simplified form as a prelude to the more detailed description that is presented later.
In accordance with an embodiment, a fire pit is provided that is fueled by a small, disposable propane cylinder. In an embodiment, the small, disposable cylinder is directly connected to the fire pit without a hose.
In accordance with an embodiment, the fire pit includes a pilot light extending through media and having a fuel feed and an air feed. The fuel feed is provided by a conduit that leads to an electrode for the pilot light. The air feed is provided by a perforated cover that extends around the electrode.
In an embodiment, a fire pit includes a manifold for permitting the attachment of multiple propane cylinders. The manifold may include, for example, multiple input attachments for multiple propane cylinders, allowing one or more propane cylinders to be attached to the manifold to provide fuel to the fire pit.
Other features of the invention will become apparent from the following detailed description when taken in conjunction with the drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top side perspective view of a fire pit in accordance with an embodiment of the invention;
FIG. 2 is a bottom side perspective view of an alternate embodiment of a fire pit;
FIG. 3 is a top view of a burner assembly for the fire pit of FIG. 2 in accordance with an embodiment;
FIG. 4 is a top view of a burner assembly for the fire pit of FIG. 1, with lower media in place;
FIG. 5 is a side perspective view of a portion of the burner assembly of FIG. 3;
FIG. 6 is a top, side perspective view of the fire pit of FIG. 2, with a cover positioned over a fire bowl of the fire pit;
FIG. 7 is a top, side perspective view of the fire pit of FIG. 2, with a removable shelf component positioned over a fire bowl of the fire pit to form a table;
FIG. 8 is a bottom side perspective view of an alternate embodiment of a fire pit in accordance with an embodiment;
FIG. 9 is a cutaway view of a manifold for the fire pit of FIG. 8;
FIG. 10 is a side perspective view of the manifold of FIG. 9; and
FIG. 11 is a cutaway view of a manifold in accordance with an alternate embodiment.

DETAILED DESCRIPTION

In the following description, various embodiments of the present invention will be described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the embodiments. However, it will also be apparent to one skilled in the art that the present invention may be practiced without the specific details. Furthermore, well-known features may be omitted or simplified in order not to obscure the embodiment being described.
Referring now to the drawings, in which like reference numerals represent like parts throughout the several views, FIG. 1 shows a fire pit 20 in accordance with an embodiment. An alternate embodiment of a fire pit 120 is shown in FIG. 2. Briefly described, the fire pits 20 and 120 are each configured to provide a flame utilizing gaseous fuel. In an embodiment, the gaseous fuel is provided by one or more small, disposable cylinders. These small, disposable cylinders may be, for example, 16.4 fluid ounce, or “one-pound,” propane cylinders, such as the cylinders 46 shown the in drawings. Such cylinders are well known in the propane industry, and are sold by a variety of manufacturers, including The Coleman Company, Inc., assignee of the present invention. Another example is a 14.1 fluid ounce propane cylinder. Both the 16.4 ounce and the 14.1 ounce propane cylinders utilize an industry standard (for small disposable propane cylinders) one inch threaded fitting.
The embodiment shown in FIG. 1 utilizes two small, disposable propane cylinders 46, and the embodiment shown in FIG. 2 uses one cylinder, but more than two may be used.
Each of the fire pits 20 and 120 includes a centrally located bowl 22. In the fire pit 120 shown in FIG. 2, a single burner 26 (FIG. 3) is mounted in a bottom 24 of the bowl 22. Preferably, the bottom 24 (e.g., FIG. 2) would be flat to minimize a volume of propane needed to fill the bowl. In the embodiment shown in FIG. 2, the single burner 26 includes multiple orifices 28 to control and spread the flow of propane. The bowl 22 includes a centrally located weep hole 30 to allow rainwater to escape, covered with a screen 32 to contain media 34 (e.g., FIGS. 1 and 4, described in more detail below) that is situated in the bowl 22.
The media 34 may be, for example, a generally porous media, in this configuration, of two different levels, a lower, base level 36 (FIG. 3) and a second, top level 38 (FIG. 1). The base level 36, shown for example in FIG. 4, is a very fine gravel-looking material, crushed rock or other material that is of sufficiently small size to be somewhat tightly packed so as to reduce the volume of space the gas has to travel through and of large enough size that it does not plug the orifices 28 of the burner 26.
In an embodiment, the base layer 36 of media 34 is arranged to fill from the bottom 24 to a level just above the burner 26 to allow propane to flow through the layer 36 to a surface for combustion. The size of each of the pieces in the media 34 in the base layer 36 is preferably larger than one millimeter to prevent plugging of the orifices 28, and preferably smaller than ten millimeters, more preferable below five millimeters, to keep the void space between the pieces of the base layer 36 of the media 34 small.
The shape of the material used in the base layer 36 of the media 34 may be, for example, something similar to crushed rock. The angularity of the shape also helps to reduce the void space, but round or other shaped media could be used as well. Overall, the goal is to have enough space for the propane to travel through to fill the base of the bowl and to fill the volume of the bowl as much as possible but yet constrict the movement of the propane so that it does not come up too fast. Also, the base layer 36 of the media 34 is preferably spaced tightly enough relative to one another so as to keep air from going down into the media. In this manner, combustion occurs mainly at the surface of the base layer 36, instead of within the base layer.
The second layer 38 (FIG. 1) of media 34 is used to further distribute the propane to give randomness to the combustion. This second layer 38 of the media 34 may be several materials, including, but not limited to, natural or synthetic rock or stone, synthetic glasses, or ceramics. The second layer 38 is preferably decorative in nature to match the rest of the fire pit 20 or 120.
In an embodiment, the fire pit 120 or 20 includes an electrode 40 (FIG. 5) extending out of a tube 42 that is mounted vertically to the burner 26. The electrode 40 extends up through the bottom 24 of the bowl 22 and into the tube 42. The tube 42 is in fluid communication with an end of the burner 26 via an orifice (not shown) that allows a metered amount of fuel to travel into the tube. The fuel passes within the tube 42 in close proximity to the electrode 40, traveling in a circular fashion.
In an embodiment, the electrode 40 passes through the base layer 36 of the media 34 and into the second layer 38. The end of the electrode 40 may slightly protrude through the second layer 38, or may only slightly extend into it, or may be located somewhere in between these two locations.
In the embodiment shown in FIG. 5, the upper end of the tube 42 is formed from a rolled piece of screen 44. There may be a top to the tube 42 to keep media out of the tube. The rolled piece of screen 44 spaces the media 34 away from the electrode 40 and allows air to pass to and around the electrode. Fuel flowing through the rolled piece of screen 44 generates turbulence, which allows air to be entrained into the fuel and provides a mixture that is readily lit with an electric spark from the electrode 40. In lieu of a solid tube, it is better to have a perforated tube or a tube with some kind of air openings, such as the rolled piece of screen 44, that allows air to reach the electrode 40 to provide the mixture of air and fuel at the electrode. If the tube were solid to the tip of the electrode, raw fuel would bathe the electrode, and there would be little to no oxygen for combustion.
The tube 42 feeds fuel directly to the electrode 40. The fuel feed to the electrode 40 via the tube 42 and the air feed via the rolled piece of screen 44 permits a form of pilot light that is lit almost immediately upon starting of the fire pit 20 or 120. In the absence of fuel flow directed to the electrode 40, fuel would have to completely fill the bowl up to the level of the electrode (or close to it) to be in close enough proximity to ignite. Propane fuel, being heavier than air and being introduced at the bottom of the bowl, fills the bowl from the bottom up through the media. The fuel cannot be ignited until that fuel can mix with some air above the media, so match lighting would be very difficult or dangerous, and electronic ignition would be difficult without the fuel and air being fed to the electrode 40.
Although described as a “tube,” the tube 42 may in fact be any structure that surrounds or partially surrounds the electrode 40, referred to generally herein as a “sleeve.” The openings in the sleeve preferably extend up the sleeve so as to provide an air feed along the length and to
The burner 26 in this application is a flat, coiled tube burner with a series of small orifices 28 drilled in different orientations to facilitate distribution of the gaseous fuel. The gaseous fuel is delivered to the burner 26 through the bottom 24 of the bowl 22 or through some other part of the bowl, and the burner tube extends to a regulator 43 (FIG. 2). As discussed above, in an embodiment, the gas fuel source for the fire pit 20 or 120 is one or more small, disposable propane cylinders 46. The pressure inside the propane cylinders 46 is taken down to a lower pressure by the regulator 43. In an embodiment, no primary air is introduced to the fuel to allow the raw fuel to enter the bowl 22 without combustion air.
The electrode 40 may be powered by a standard igniter, such as a standard electronic ignition system provided in many fuel burning appliances. It may be, for example, battery or high energy electric powered, a piezoelectric device, or another suitable device. In an alternate embodiment, the fire pit 24 is lit using a match or a lighter.
In another embodiment, multiple burner tubes, such as the burner 26, could be installed in a common bowl, such as the bowl 22. This feature would facilitate larger bowls and more flame in the bowl.
There is a finite amount of fuel that can be pulled from a small, disposable cylinder and fuel that is pulled too fast may cause frosting of the small, disposable propane cylinder 46, thereby diminishing flow. For a large bowl, multiple burners may be used within the bowl to avoid this problem. In an embodiment, the multiple burners may be tubular in nature and run concentrically in the bottom of the bowl. The multiple burners may also be fed by multiple cylinders and multiple regulators. For example, FIG. 1 shows a fire pit 20 having two small, disposable propane cylinders 46, and two concentric burners 126, 128 (FIG. 4). Other numbers may be used, and the number of burners does not have to match the number of propane cylinders.
Turning now to FIG. 8, an alternate embodiment of a fire pit 220 is shown in which a manifold 230 (best shown in FIG. 10) permits two propane cylinders 46 to be attached to a single regulator 302. The regulator is connected to a control 304 and an igniter assembly 306.
The manifold 230 includes a common conduit 231 that extends to two one- way check valves 232, 234. In accordance with an alternate embodiment, more than two canisters may be attached to a similar manifold. In such an alternate embodiment, additional one-way check valves, such as the one way check valves 232, 234, may be provided.
In the embodiment shown in the drawings, the one- way check valves 232 and 234 are similar, and thus, for ease of description, the structure of only one, the check valve 234, is described herein. As can be seen in FIG. 9, the one-way check valve 234 includes a gasket 236 on the underside of a shoulder 238 of a valve stem 240. The valve stem 240 is biased downward in FIG. 9 by a spring 242.
The one-way check valve 234 includes a standard probe 246 having a top 250 that engages the gasket 236 of the valve stem 240. The probe 246 inserts into an opening on a top of one of the propane cylinders 46 when a threaded top of the propane cylinder 46 is screwed into a threaded cylinder sleeve 252 on the one-way check valve 234. As is known, propane cylinders, such as the propane cylinders 46, include an internal valve (not shown) that is structured so that when a probe, such as the probe 246, is inserted into the top opening of the propane cylinder 46, gas is released from the propane cylinder 46.
When a propane cylinder 46 is threaded onto the cylinder sleeve 252, the cylinder sleeve 252 stabilizes and supports the propane cylinder 46. A gasket 253 seats the top of the propane cylinder 46 against the top of the cylinder sleeve 252. During attachment of the propane cylinder 46, the probe 246 is automatically inserted into an opening at the top of the propane cylinder 46. This insertion of the probe 246 into the opening opens the internal valve (previously described, but not shown) on the propane cylinder 46.
With the propane cylinder 46 in place, fuel in the propane cylinder 46 is free to escape out of the propane cylinder 46, creating gaseous fuel. This fuel flows up a conduit 254 that extends through the center of the probe. This conduit 254 extends to the valve stem 240. The pressure of the fuel flow out of the propane cylinder 46 drives the valve stem 240 away from the top 250 of the probe 246 against the bias of the spring 242, moving the gasket 236 away from the top 250 of the probe 246. Thus, the gaseous fuel is free to flow into the conduit 231 for the manifold 230. The spring 242 is a light duty spring and is chosen so that it is sufficient to drive the gasket 236 against the top 250 of the probe 246 only when a propane cylinder 46 attached to the one-way check valve 234 is empty or is substantially empty. Thus, under normal conditions, when the propane cylinder 46 is not empty, fuel within the propane cylinder 46 is free to flow out of the propane cylinder 46 and into the manifold 230 as soon as the propane cylinder 46 is attached to the one-way check valve 234. Likewise, when the propane cylinder 46 is disconnected from the one-way check valve 234, the spring 242 closes the opening in the one-way check valve 234 by driving the valve stem 240 and the gasket 236 into contact with the top 250 of the probe 246.
Any attempt of fuel or air to flow in the opposite direction (i.e., into the propane cylinder 46 from the manifold 230) is prevented because, for fuel to flow in that direction, the air and/or gas pressure in the manifold 230 must be greater than the pressure within the propane cylinder 46. However, when such a pressure differentiation is present, the spring 242 is free to drive the valve stem 240 and the gasket 236 to close the opening at the top 250 of the probe 246, preventing the flow of gas into the propane cylinder 46. This feature prevents the manifold 230 from being used to fill propane canisters.
The manifold 230 includes an outlet 310 that connects to the bottom of the regulator 302. In an embodiment, the outlet 310 is permanently connected to the regulator 302.
In accordance with an embodiment, a manifold 330 (FIGS. 10 and 11), similar to the manifold 230, may be provided for connecting two or more propane cylinders 46 to a female connector (not shown) for any burning appliance that is designed for direct connection with a small, disposable propane cylinder 46. To this end, the manifold 330 includes two or more one-way check valves 232, 234 (only two are shown in FIG. 10, but additional check valves may be provided if more than two propane cylinders 46 are to be attached to the manifold 330). In addition, the manifold 330 includes an outlet connector 340 in fluid communication with the interior of the manifold. The outlet connector 340 includes exterior threads 342 for connecting to a female connector of a burning appliance that is configured to receive the threaded top of a small, disposable propane cylinder, such as the propane cylinders 46. In addition, the outlet connector 340 includes an interior SCHRADER valve 344 or other sealing device.
In use, the exterior threads 343 are threaded into a female connector for a fuel burning appliance (not shown, but described above). The female connector is designed to receive a threaded top of a propane cylinder, such as the propane cylinders 46. The female connector includes a probe, similar to the probe 246 in FIG. 9, that engages the SCHRADER valve 344, opening access to the interior of the manifold 330. One or more propane cylinders 46 are connected to the one- way check valves 232, 234. These propane cylinders provide propane to the interior of the manifold 330 and out of the outlet connector 340. The one- way check valves 232, 234 permit one or more of the propane cylinders 46 to be removed during operation, with the remaining cylinders that are attached to the manifold 330 continuing to supply propane to the manifold 330 and the outlet connector 340.
By using the manifold 330, the flow of propane out of propane cylinders 46 that are attached to the manifold 330 is decreased. For example, if two propane cylinders 46 are attached to the manifold 330, then the flow rate is cut in half. If a manifold is provided to which three propane cylinders 46 may attach, then the flow rate is cut to approximately a third, and so forth. In this manner, fuel burning appliances that require a large amount of propane are less likely to freeze a propane cylinder 46 as a result of propane being drawn from the propane cylinder.
The bowl 22 is housed within a tubular frame 50. In this embodiment, the tubular frame 50 is painted steel, but another suitable material may be used. The frame 50 is segmented into multiple pieces that are bolted together. This includes decorative outer plates 52 that extend radially outward from the bowl 22 of the fire pit 20. These decorative outer plates 52 are toroidal in shape and are cut into segments to allow a smaller package for shipping, thus lowering shipping costs. In addition, the frame 50 may be a knock-down or collapsible type frame to facilitate shipping.
In an embodiment shown in FIG. 7, a shelf 160 is formed of a frame, such as a metal mesh bottom 170 with an outer steel ring 172. A separate cover piece 162 is provided that may be removably placed on top of the shelf 160, for example over the metal mesh bottom 170 and within the outer steel ring 172. In this position, the cover piece 162 is used as a top surface of the shelf 160, for example while a fire is burning in the bowl 22. The appearance of the cover piece 162 within the shelf 160 is shown in FIG. 6. In a stowed position, that same cover piece 162 may be moved to the top of the bowl 22 to cover the bowl (FIG. 7), creating with the decorative outer plates 52 a large, flat surface that may be used as a table rather than a fire pit.
In an alternate embodiment, the cover piece 162 may be permanently attached to the frame 50, thus forming a shelf. The cover piece 160 may be formed, for example, of the same decorative material as the decorative outer plates 52.
As can be seen in FIG. 6, when a fire is lit in the bowl 22, the bowl 22 may be covered with a screen 56 or some other protective device. The screen 56 aids in preventing individuals from getting too close to the flame and keeps the stone media from popping out of the bowl.
In operation, the small, disposable propane cylinder 46 is attached to the regulator 43 and a valve (not shown, but known) on the regulator is opened, for example by rotating a knob 58 on the regulator 43 to allow fuel to flow to the burner 26. The fuel is ignited by electronic ignition (e.g., using the electrode 40), or by match light or via a lighter. The preliminary stage of combustion keys a smaller flame with an equal amount of blue flame and orange flame. This flame pattern represents the oxygen in the media 34 being burned off. As that oxygen is burned off, then the fuel transitions into a much more yellow colored flame, which is the preferred look as it is much more visible, particularly at night, and gives the look of a wood fire. In an embodiment, the volume of fuel combusted/burned may be such that surface temperatures would stay below a threshold, which would allow the device to be used on a standard wooden deck without further precautions.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. The term “connected” is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate embodiments of the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

1. A decorative fire pit, comprising:

a fire bowl;

media in the fire bowl;

a burner in contact with the media and for supplying gaseous propane to the media; and

a connector for direct connection of at least one small, disposable propane cylinder, the connector being in fluid communication with the burner.

2. The fire pit of claim 1, wherein said at least one small disposable cylinder is directly connected to the fire pit without a hose.

3. The fire pit of claim 1, further comprising a manifold for direct connection of two or more small disposable propane cylinders, the manifold being in fluid communication with the burner.

4. The fire pit of claim 3, wherein the two or more small, disposable propane cylinders are each one-pound propane cylinders.

5. The fire pit of claim 3, wherein the manifold is configured for direct connection of two or more small disposable propane cylinders via one inch threaded fittings.

6. The fire pit of claim 1, wherein the small, disposable propane cylinder is a one-pound propane cylinder.

7. The fire pit of claim 1, wherein the connector is configured for direct connection of a small disposable propane cylinders via a one inch threaded fitting.

8. A fire pit, comprising:

a fire bowl;

media in the fire bowl;

a burner for supplying gaseous propane to the media; and

a pilot light, comprising:

an electrode;

a sleeve surrounding at least a portion of the electrode, the sleeve extending through at least a portion of the media, the sleeve including an opening along a length of the sleeve; and

a fuel feed for supplying gaseous propane from the burner to inside the sleeve.

9. The fire pit of claim 8, wherein the electrode extends through the burner.

10. The fire pit of claim 8, wherein the burner is covered by the media, and wherein the electrode and the sleeve extend out of the media or flush with the top of the media.

11. The fire pit of claim 10, wherein the sleeve comprises screen material.

12. The fire pit of claim 8, wherein the sleeve comprises screen material.

13. The fire pit of claim 8, wherein the media comprises a base media and an upper media, and wherein the sleeve and the electrode extend out of the base media.

14. The fire pit of claim 13, wherein the sleeve and the electrode extend out of the upper media.

15. The fire pit of claim 8, wherein the sleeve comprises a plurality of openings along a length of the sleeve.

16. A fire pit comprising:

a fire bowl; and

a decorative outer plate that extends radially outward from the fire bowl.

17. The fire pit of claim 16, wherein the decorative outer plate substantially surrounds the fire bowl and is provided in segments.