CA2211967C - Natural draft portable campfire pit - Google Patents

Abstract

In a campground fireplace, it is common to have a wood-burning device permanently set high on a post, which affords a poor means of warmth and cooking. In this invention, a portable tub fitted with handles presents a more practical and efficient means of generating heat. Perforations along the circumference of the tub provide combustion air by natural draft. A center column may provide a medium for leaning the firewood upright onto it, and can be used to rest the tub at an elevated level by sliding it vertically over a sunken post. An annulus may be fastened to the tub from which a chain may be secured to a tree, a sunken pin, or a post. A removable cooking grille may be placed on the top of the tub. Finally, this device may be fitted with an internal bladder to contain and transport ashes to a disposal site.

Description

DESCRIPTION
This invention relates generally to novel and advantageous improve-meats in campfire pits. It is common, in devices for generating warmth and providing cooking heat found at most campgrounds, to consist of an elevated metallic box mounted onto a post into which firewood is burnt. A tilting grille is normally provided for cooking purposes. Another type commonly found is an open earthen dug-out, surrounded with rocks which contains the campfire to prevent its spread. Sometimes, these rocks are substituted with a metallic ring, 10 such as a used farm tractor's or truck's rim. Yet another type is the classical open-faced fireplace constructed of rocks or bricks and mortar.
Installations of these types are, however, inefficient because:
1) Their permanent setting may interfere with the movements of the campsite user and the site's setting. This is owing to the diversity in the camping layout which is dependent on the mode of transportation and type of camper utilized, or type and number of tents pitched onto the site;
20 2) Most do not offer warmth at the foot level due to their elevation from the ground;
3) All are permanent fixtures which cannot be relocated with changing winds, yielding smoke discomfort especially why directed towards the camper/trailers, tents, or picnic tables;
4) Most do no oiler cleanliness, as ashes may be blown in and around the campsite by gusts of wind;
5) Most do not oiler an efficient and clean burn due to the lack of combustion air;
10 6) Most do not offer wind protection from any direction, which may create hazards with ambers and sparks being blown away;
7) All make it difficult and messy to clean out the ashes;
8) None are portable, capable of storing and transporting kindling, or be removed from the site without leaving a heap of unsightly ashes;
9) Nee may be used as an ulterior application out-of season.
20 We have found that these disadvantages may be overcome by providing a portable cylindrical metallic tub, open at the top, with perforations along its circumference. The purpose of these holes is to provide natural draft openings for combustion air. This tub may be fitted with either a lip at the top, or one or more handles securely fastened onto its side. This lip, or the handles, make it easier to grasp and transport the tub, especially if filled with kindling.
A vertical center post may be fastened at the bottom of the tub and provide a leaning medium for fire logs when arranged in a teepee fashion. This post, coupled with the combustion air holes, significantly improve the burning effici~cy, offer a hotter and cleaner burn, and minimize smoke. This open top circular tub, with its side perforations limiting the amount of combustion air, serves as an ideal shield against wind from any direction, and minimizes carry-over of sparks. There is no need for openings at the bottom of the tub, thus 10 ambers and ashes are contained within the tub. Ashes are conveniently disposed by inverting the tub into a respective container.
Because this tub rests on the ground, the radiant heat is generated at foot level, where it is sometimes most needed. Sitting or standing close-by is also comfortable, due to the cleaner and more efficient burn; thus less smoke.
This portable tub may be rendered semi-permanernt if an annulus is fastened onto the tub, with one end of a chain or steel cable hooked into said annulus, the other end fastened to a tree, or to a sunken post. This is for the 20 sole purpose of theft prevention. If the sunken post is the original support of the now decommissioned metallic box campground fireplace, this box may now be conveniently used to store firewood. A tarp wrapped around this box with bungee cords may assure readily available dry wood.

Even in a semi-permanent arrangement, the tub can be relocated within the radius of its restraints. If the wind does create a problem with some smoke, the tub can be relocated, eliminating downwind discomforts or hazards. The tub may also be moved to prevent occasional sparks from damaging camping gear.
This natural-draft portable campfire pit may also be moved about the site to accommodate versatility in the camping layouts.

A more permanent arrangement would consist of a sunken metal post, with the tub's hollow centre column inserted over said post. This would allow fastening the tub onto the sunken post, as well as elevating the fireplace if solely used for cooking purposes, such as in day-use campgrounds.
Additionally, a removable grille may be fitted onto the top of the tub for cooking purposes, such as boiling water in a kettle, cooking with a cast ire skillet, and other uses.
20 Further, when transporting this container to and from campsites, and for the purpose of storing dry kindling, a tarp may be draped over and fastened onto the tub, with one end of one or more bungee cords attached to the tarp, and the other end hooked into the combustion air holes.

Finally, and especially in northern climates, ice the camping seas comes to a close, this tub can still be used as an interior container for storing, and disposing of, ashes. Simply by inserting a bladder inside the tub, thus covering the combustion holes, this comainer may store, without seepage, ashes from wood burning facilities which provide heat and comfort inside the home.
The conveniently located handles, much the same as for campsite use, render the transporting of these ashes quite easy, and the disposing very clean, by means of inverting the said tub.

It is an overall aim of the present invention to provide a campfire pit having an improved design over existing facilities or devices.
It is also an aspect of this invention to provide a more efficient, and cleaner burning, device over present-day installations, using sound engineering practices and knowledge.
Yet another object of the present invention is to procure a portable campfire unit which may offer protection from blowing smoke and sparks, 20 without rearranging the campsite layout.
Still another aim of the present invention is to supply a container for storing the combustion by-products, mainly ash, and a safe and easy means of disposing same.
Another advantage of this invention is to offer a portable means of storing and transporting firewood, burning firewood, and storing, transporting and disposing of ashes, all within the same container.
Finally, one last objective of this invention is to offer a product which can be easily and inexpensively manufactured.
Other objects and advantages of the present invention may present themselves from the following description when considered with the accompanying drawings, in which:
Figure 1 is an elevation view of one embodiment;
Figure 2 is a top plan view partly in secti~ of another embodiment, having two carrying handles and a centre post;
Figure 3 is an elevation partly in section showing another embodiment, having two carrying handles and a tipping handle, as well as a centre post, illustrating how kindling can be stored inside the embodiment;
Figure 4 illustrates the natural draft principle of this embodiment;

Figure 5 shows an annulus fastened onto the side of the embodim~t, from which a chain or a steel cable may be attached, and strung to an adjacent sunken post, ~to which it is fastened as an anti theft measure;
Figure 6 demonstrates how the fire can be stoked with the fire pit in use, by means of a hinged grille, also fitted with handles, which may be swung open on either side, with cookware still in place;
10 Figure 7 depicts an elevati~ partly in secti~ of a typical site arrangement, with the embodiment mounted onto a long sunken post, and the tub's hollow centre column fastened rigidly onto said post, affording a higher elevation of the cooking surfaces;
Figure 8 shows yet another typical site arrangement with an existing elevated metallic box campground fireplace, with the embodiment fastened to the fireplace's upright post;
Figure 9 illustrates how ashes are removed from the embodiment;

Figure 10 is an elevation view of the embodiment, with a protective tarp draped over the tub, for the storage of dry kindling, and;

Figure 11 illustrates the embodimecit fitted with an internal bladder to contain ashes.
Referring now in more detail and by reference characters to the drawings which designate id~tical or corresponding practical embodim~ts of the invention throughout the several views, Fig. 1 illustrates a cylindrical metallic tub or container 10, open at the top, with perforations 11 arranged in random or selectively positioned along the tub's circumference. At or near the top of the tub 10, is formed a neck or constriction 12, which then extends 10 radially in an outwardly and upwardly fashion to the very top of the tub, thus forming a ridge, or a lip 13. This lip offers a grasping medium for which the tub may be manually carried. The bottom 25 of the tub is totally free of openings. The top of the tub is fitted with a removable grille 14, which purpose will be disclosed later in this description.
Referring now to Fig. 2, which shows a top view of the embodiment, the tub 10 is now fitted with two carrying handles 20 on each side. The handles 20 each comprise of a wooden dowel 21 or metallic spring 21-a fastened to two metallic side rails 22 by means of screws 23, rivets, or other 20 like fasteners. The purpose of the wooden or metallic spring handles 21 is not to store any radiant heat which may be damaging to the bare hands. The metallic side rails 22 are in turn radially and rigidly attached to either the side of the tub 10, near the top, or under the lip 13, i.e to the neck 12. Fasting of the rails 22 to the side of the tub 10 are also by fasteners 23, or by fusion welding. The removable metallic grille 14 is also partially shown resting on top of the tub 10. A m~allic centre post 24 may also be extending in an upright fashion from the bottom 25 of the tub, also rigidly fastened. Finally, Fig. 2 illustrates how the cylindrical side of the tub 10 assists in redirecting a wind pattern 28 around the tub, thus yielding an aerodynamic profile 29 to the tub.
Referring further to Fig. 3, which illustrates an elevation view partly in section of yet another embodiment, whereby kindling 30 is stored within the container 10. Said kindling 30 is neatly stacked against the centre post 24 for carrying purposes. This embodiment is also fitted with two carrying handles located at or near the top of the tub 10, and an additional tihing handle 26 comprising the same components as handles 20, i.e. a wooden or metallic spring handle 21, attached onto side rails 22 by means of fasteners 23. The side rails 22 are in turn attached to the side of the tub 10 with screws 23 or other like devices, or by means of fusion welding. The purpose of the tilting handle 26 is to invert the container to quickly remove the kindling 30, among other uses, which shall be disclosed later in this description.

Figure 4 illustrates the conceptual principle of the natural draft theory, as applicable to this embodiment. For illustrative proposes, a partial cut-away view is presented for clarity. The kindling 30, arranged in a teepee fashion against the central post 24, offers ample air movement between the individual pieces of kindling. Once the kindling 30 is ignited, the flame 31 heats up the surrounding air 32 inside the tub 10. This warm air 32, being less dense than the external or ambient air 33, thus rises due to buoyancy. The displaced air 32 rising from the combustion process needs to be replaced by the outside air 33, thus creating an air velocity, also known as an air current 34. This combustion process is regulated by the amount of external air 33 which may pass through the perforations, or combustion air holes 11, as the air velocity is dependealt on the size of the holes. Therefore, the wind velocity 28 as shown 10 in Fig. 2 is not only deflected from the curvature of the tub 10, but penetration through the combustion air holes 11 is also limited. The end results are that even with a wind velocity 28 higher than the displaced air velocity 34, the area of the combustion air holes 11 is negligible compared to the overall area of one side of the tub. Therefore, the velocity of the hot air 32 exiting the tub remains relatively constant, with ash and spark entrainment 35 being minimized. This results in a more controlled and cleaner combustion of the firewood 30, with relatively little smoke 36.
With fireuvood burning inside the tub, the grille 14 d~icted in Figures 20 1 and 2, when mounted onto the top of the tub 10, offers a means of reposing a kettle for boiling water, barbecuing meat or poultry, cooking with a cast iron skillet, or other purposes. Although Figures 1 and 2 illustrate a grille covering the whole of the top surface of the tub, a partial grille may also be utilized, enabling stoking of the fire while cooking.
Even if smoke, ashes, or sparks do create a hazard, or discomfort, the tub 10 can be moved to a safer locale by means of one of the handles 20 which, if they are wooden or fashioned from a metallic spring 21, may be safely touched if the person wears protective gloves.
Figure 5 illustrates an annulus 15 rigidly fastened to the side of the tub 10. A chain 16, or any other like device, having one end hooked into this annulus 15, and the other end of said chain 16 also hooked to a second annulus 15, serves as an anti-theft device for securing the tub 10 onto the campsite when attached to a sunken post 17.
Figure 6 demonstrates another embodiment with a split grille 14 fastened to the tub 10 by means of hinges 38. The purpose of the hinges is to permit a user to stoke the fire with wood 30 simply be swinging part of the grille 14. The grille 14 is fitted with like handles 37 as described previously, fastened by means of side rails 22. Stoking of the fuel can be done without disturbing the cookware 39, which makes no part of this embodiment.
Figure 7 depicts yet another view of a typical site arrangement, shown in a partly sectional elevation. The campfire pit 10 is now mourned in an elevated position by inserting the hollow centre column 24 over a longer sunken post 17 than shown in Figure 5. This affords a higher elevation of the cooking surfaces. This embodiment illustrates a single lifting handle 20, and a tilting handle 26. A chain 16 attached to the tub's annulus 15 and another ring 15 secures the tub to the post 17. Additionally, the tub 10 can be secured to the post by means of a faster 18 at the top of the center column 14. Removing the fastener 18 allows the caretakers to remove the tub from the post, and to tilt the ashes as subsequently shown in Figure 9. The length of the chain 16 is sui~cier~t for this purpose.
10 Figure 8 shows a typical campground setting and how the tub 10 may be attached to an existing post 17 by means of fasting one end of a chain 16 and the annulus 15. In this case, the post happens to be the support for a previous metallic-box campfire pit 41 on the campsite. This box 41, which makes no part of this invention, is now utilized to store kindling and firewood 30. Figure 8 also shows a variation in the embodiment's side perforations, these being shown as a wire meshing 19.
The superior burning efficiency of the firewood results in a cleaner burn, whereby all that remains in the tub are essentially ashes. Figure 9 20 illustrates how the ashes 45 may be effectively removed by inverting the tub 10 by means of grasping one of the top carrying handles 20, and the lower tipping handle 26 (as shown in Figures 7 and 8). These ashes 45 may the be confined to a proper disposal containment 4Z, which makes no part of the embodiment. The chain 16 which acts as a constraint in Figure 8 may be substituted with a wire rope 16-a, also double-ended with annuli 15. The kindling 30 stored in the metallic box 41 may be further protected from the elements if draped with a tarp 43.
Figure 10 shows how a tarp 43 may be draped over the tub 10 for storing dry kindling against the elements of nature. Bungee cords 48 which have one end fastened to grommets 44 in the tarp, are strung down along the side of the tub and attached to the tub by means of hooks 49 inserted into the tub's combustion air holes 11.
Figure 11 illustrates how an internal bladder 46 may be fitted into the tub 10 and held in place by means of a sewn elastic 47 str~ched around the constriction 12 of the tub. This bladder effectively seals the combustion air holes 11 such that ashes 45 may be cleanly stored inside the tub. This is most convenient for long term storage of ashes which are removed from conven-tional wood-fired furnaces nonrnally found in the colder climate homes.
Cleaning of these furnaces and/or fireplaces must be undertaken at regular intervals, and the storage capacity of the tub is su~cient for a number of successive clean-outs. Carrying and disposing of these ashes are done in a similar fashion as previously outlined in this disclosure.
Thus it has beg described and illustrated a novel and unique campfire pit burner which fulfills all of the associated objectives and advantages sought thereof.
It must be understood, although it is not shown, that other appendages may be incorporated to this embodiment with no deviations from the stated embodiment's intended purposes, these appurtenances serving either useful or cosmetic means:
a) Legs may be rigidly fastened to the bottom of the embodiment to 10 provide an air space serving as a heat shield to the ground;
b) The same purpose may be achieved if the embodiment is laid flat directly onto a heat-resistant surface, such as a concrete patio pad;
c) Yet another heat-shielding medium may be in the form of interlocking bricks stacked radially along the perimeter of the embodiment, with allowance for combustion air holes;
d) And the overlying grille may be substituted or overlaid with a wire mesh screen to further prevent spark carry-over.
It should also be understood that any changes, modifications, 20 variations, or other applications or uses will become apparent to those skilled in the art upon consideration of this disclosure and its associated drawings.
It should further be understood that all such changes, modifications, variations, or any other applications which do not depart from the scope and spirit of the

Claims (14)

1. A storage container for carrying and burning firewood, comprising a perforated-side tub, open at the top, the perforations forming combustion air holes in the side of the tub, and the top of which is fitted with a lip as a means of grasping and carrying said container.

2. A container as defined in claim 1, which comprises one or more handles extending outwardly from the side of the tub and rigidly secured thereto.

3. A container as defined in claim 1 or claim 2, which comprises a hollow center post extending upright from the bottom of the tub and rigidly secured thereto.

4. A container as defined in claim 1, claim 2, or claim 3, which comprises an annulus extending from the side of the tub and rigidly secured thereto, onto which a security link may be fastened.

5. A container as defined in claim 1, claim 2, or claim 3, which comprises a removable or hinged grill which may be set onto the top of the tub.

6. A storage container for carrying and burning firewood comprising: a perforated-side tub, open at the top, the perforations forming combustion air holes in the side of the tub; one or more handles extending outwardly from the side of the tub and rigidly secured thereto; a hollow center post extending upright from the bottom of the tub and rigidly secured thereto; an annulus extending from the side of the tub, also rigidly secured thereto; and a removable or hinged grill which may be set onto the top of the tub.

7. A container as defined in claim 1, claim 2, or claim 3, fitted with a tarp equipped with grommets, draped over and fastened to the tub by means of bungee cords with one end tied to the tarp grommets, and the other end hooked into any one of the combustion air holes.

8. A container as defined in claim 4, fitted with a tarp equipped with grommets, draped over and fastened to the tub by means of bungee cords with one end tied to the tarp grommets, and the other end hooked into any one of the combustion air holes.

9. A container as defined in claim 5, fitted with a tarp equipped with grommets, draped over and fastened to the tub by means of bungee cords with one end tied to the tarp grommets, and the other end hooked into any one of the combustion air holes.

10. A container as defined in claim 6, fitted with a tarp equipped with grommets, draped over and fastened to the tub by means of bungee cords with one end tied to the tarp grommets, and the other end hooked into any one of the combustion air holes.

11. A container as defined in claim 1, claim 2, or claim 3, fitted with an internal noncombustible bladder to block off all combustion holes in order to store, carry and dispose ashes.

12. A container as defined in claim 4, fitted with an internal noncombustible bladder to block oil all combustion holes in order to store, carry and dispose ashes.

13. A container as defined in claim 5, fitted with a tarp equipped with grommets, draped over and fastened to the tub by means of bungee cords with one end tied to the tarp grommets, the other end hooked of the bungee cord hooked into any one of the combustion air holes, and the tub's internal lined with a noncombustible bladder to block off all combustion holes in order to store, carry, and dispose ashes.

14. A container as defined in claim 10, fitted with an internal noncombustible bladder to block off all combustion holes in order to store, carry, and dispose ashes.