US20170198916A1

US20170198916A1 - Log stove and fire stand

Info

Publication number: US20170198916A1
Application number: US15/401,582
Authority: US
Inventors: Ronald John Rohbock; Lloyd LeRoy Wall; Thomas Jonathon Jeffs
Original assignee: Rocky Mountain Log Stoves LLC
Current assignee: Rocky Mountain Log Stoves LLC
Priority date: 2016-01-08
Filing date: 2017-01-09
Publication date: 2017-07-13

Abstract

A log stove and fire stand are disclosed wherein the fire stand has a grill with three adjustable legs positioned over the log stove to complement the structural integrity of the burning log stove. The log stove may include a variable cross-section static air flow design and a ventilator gate that provide a method to inject excessive air (oxygen) flow into the combustion chamber throughout the burn cycle for complete fuel consumption. An excessive air volume to fuel ratio insures complete combustion of the billet thus reducing pollution.

Description

FIELD OF THE INVENTION

The present invention relates to a stove for heating and/or cooking. In particular, the present invention relates to a stove formed from a single log billet.

BACKGROUND OF THE INVENTION

The present invention relates to cooking and/or warming. The invention can be used for any outdoor activities, in an emergency when the power grid goes down or other natural or manmade disasters. The invention is easily stored with an exceptional long shelf life.
The burning of an individual stump or billet as a stove is known in the art. In such prior stoves, the stove is created by using a saw to make multiple, constant width slots that extend across a diameter of and longitudinally into one end of the log billet. The intersection of these slots creates a combustion chamber where combustion of the log primarily takes place. Intake and exhaust of air occurs through the end of the billet or through the slots created in the side of the billet.
Existing log stoves exhibit poor burning characteristics. The uncontrolled burning creates a large amount of smoke, soot, and airborne particulates. Temperature control is non-existent during the entire burn cycle. The log may be unstable and unable to support a cooking utensil during approximately ¾th of the burn cycle. Existing stoves may become a hazard to persons or property when the stump burns down past the ¾th height and collapses.
In addition, ignition of existing log stoves is made by stuffing grass, leaves or other solid flammable material into the combustion chamber and setting it on fire, creating copious amount of smoke.
The present invention addresses these and other deficiencies in existing stoves by providing various advantages, including an ability to control airflow into the combustion chamber.

BRIEF DESCRIPTION OF THE FIGURES

Advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings.

FIG. 1 is a top view showing a fire stand and log billet in accordance with embodiments of the present invention.

FIG. 2 is a front view of the embodiment of FIG. 1.

FIG. 3 is a side view of a log billet in accordance with embodiments of the present invention.

FIG. 4 is a top view of the embodiment of FIG. 3.

FIG. 5 is a cross-section view of the embodiment of FIG. 3.

FIG. 5A is a cross-section view of an alternative embodiment of the ventilator gate.

FIG. 6 a perspective view of the log billet in accordance with further embodiments of the invention.

FIG. 7 shows the configuration of the slots cut into the log billet in accordance with an embodiment of the invention.

FIG. 8 shows a top view of a fire stand in accordance with embodiments of the invention.

FIG. 9 is a side view of the embodiment of FIG. 8.

FIG. 10 is a partially cut-away side view of a leg of the fire stand illustrated in FIG. 8.

FIGS. 11-12 are cross-sectional views of an embodiment of the leg shown in FIG. 10.

FIG. 13 shows a combustion diagram.

FIG. 14 shows a side view of a fire stand in accordance with embodiments of the invention.

FIG. 15 shows a top view of a base assembly of the fire stand of FIG. 14.

FIG. 16 shows a cross sectional view of a support tube and base tube of the fire stand of FIG. 14.

FIG. 17 shows a top view of a grill assembly of the fire stand of FIG. 14.

FIG. 18 shows a side view of a diffuser for use with embodiments of the grill assembly.

FIG. 19 is a perspective view a grill lock for use with embodiments of the grill assembly.

DETAILED DESCRIPTION

Throughout this application, the directional references, such as forward, rearward, left, right, bottom and top, will be used. These and other such references are relative to the firing direction of the firearm, which fires in a forward direction. Such references are used for ease in describing the present invention and should not be construed as limiting the scope of the invention. As used in the description herein and throughout the claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise: the meaning of “a,” “an,” and “the” includes plural reference, the meaning of “in” includes “in” and “on.” Also, reference designators shown herein in parenthesis indicate components shown in a figure other than the one being discussed.
The present invention addresses deficiencies in existing log stoves with, among other advantages, consistent temperature control by controlling the burn rate, which is a function of controlling air flow (oxygen) into the combustion chamber. The airflow (oxygen) is introduced into the combustion chamber through a varied volume structure.
A ventilator gate may also be incorporated at the mouth of a ventilator port to throttle airflow into the base of the combustion chamber. The initial ignition requires the greatest amount of air (oxygen) to initiate the burn cycle. After the ignition has started, the ventilator gate can be adjusted to give required maximum temperature. A mixture of alcohol or other flammable liquid may be mixed with a scented material and squirted or otherwise introduced into the combustion chamber and the ventilator port. This mixture, when ignited will initiate combustion. The scented material may be citronella, which provides an additional advantage of generating scent vapors that may serve to disperse mosquitoes and other insects.
This throttle mechanism, as described more fully below, may be made of combustible material that is consumed in the last stage of the burn cycle. Leaving ash as the only residue remaining after the burn cycle.
A fire stand may also be included as an integral reusable component of a log stove system in accordance with the present invention. The fire stand may fit over the log stove and hold cooking or other heated utensils directly over the log stove active flame front. The fire stand may support the weight of a pan or other utensil above the top surface of the log stove, thus preventing a premature collapse of the cooking surface. The fire stand may have a circular grill with three foldable legs that extend out to support the circular grill above the fire front. These legs may be adjustable and can be adjusted to various heights. In some embodiments, the legs may be adjusted from a height of one inch or more above the flame front to a height of approximately three inches above the fire spent log during the last stages of the burn cycle.
As illustrated in FIGS. 1 and 2, a fire stand 1 straddles the log billet 2 of a log stove. The stand may function to support a load, such as a cooking utensil, set in position over the log stove flame. The fire stand 1 may also prevent the collapse of the log billet 2 as it is consumed.
Referring to FIGS. 1-2 and 9-12, embodiments of the fire stand 1 comprise a wire formed circular grill 3. The grill may include multiple decreasing diameter metal rings welded in a balanced concentric pattern to form the grill 3. The grill 3 extends over at least a portion of the top surface of the log billet 2. Embodiments of the grill include female brackets 4 that extend from a lateral edge or underside of the grill 3.
Multiple legs 6 extend from adjacent an edge of the grill. The illustrative embodiments show three legs, but more or fewer may be used. The legs 6 may be collapsible. Male hinge plates or brackets 6A are attached to an upper end of the each leg. The hinge plates 6A may be connected to the female brackets 4 by roll pins 7, such that the legs 6 pivot relative to the grill 3.
Referring to FIGS. 8-12, embodiments of the fire stand may be set up initially by unfolding the three collapsible legs 6 and expanding the legs outward until the legs contact the grill leg stops 16 at approximately 20 degrees angle. The leg lock rings 17 are pushed to the unlock position. The extension leg interior tube 19 will be pulled out of the outer tube 20 to the full extend position and the lock rings 17 pulled outward setting the lock ring in the locking grooves 18. A collapsible leg assembly 6 with the captured multi-position (neutral/lock position) lock ring 17 of embodiments of the invention provides a novel push-pull lock mechanism that can be manipulated when hot by taping the lock ring with any appropriate instrument.
Referring to FIGS. 1-2, the assembled fire stand 1 be centered and positioned over the log stove combustion chamber exhaust port 14. The fire stand 1 will be leveled using the three extended legs. A flammable ignition mixture may be squirted in to the combustion chamber 9 and a ventilator port 11. This flammable mixture may be ignited with any open flame device. Alternatively, other methods of igniting the log billet may be used as would be understood by one of ordinary skill in the art. Burn temperatures can be adjusted by either opening or closing the ventilator gate 12 to achieve the desired temperature.
The fire stand height can be adjusted to maintain a preferable distant from the burning log flame front by reducing the three legs 6 height by reversing the set up procedure. Referring to FIGS. 10-12, an internal groove or swage slot 21 is provided internally in the outer tube 8 to allow an internal guide pin 9, riding in the slot 21, which prevents the extension tube 19 from falling out of the outer tube 8.
Referring to FIGS. 3-7, the log stove comprises a log billet 2. Appropriate billets may have a variety of diameters. Preferably, the log billet has a minimum of six inches outside diameter, but smaller sizes are possible. The maximum diameter may be fifteen inches or more. The log billet 2 can be any combustible wood, including evergreen or deciduous. Appropriate billets may have a variety of lengths. In preferred embodiments, the billet is at least six inches in length and may extend to thirty-six inches or more.
The log stove billet 2 has a combustion chamber 9. The combustion chamber may be generally cylindrical and bored into the billet from a top surface. Preferably the combustion chamber has a diameter of at least one inch but not greater than six inches. The combustion chamber may be machined to a depth of one inch above the base 10 of the billet 2
A ventilator port 11 may be machine or otherwise cut in the billet to intersect the chamber 9 at or near the bottom of the combustion chamber bore hole. In preferred embodiments, the ventilator port 11 may have a diameter from one inch to three or more inches.
Alternatively, the ventilator port 11 may be machine with a tapered hole to form a venturi structure 22 as illustrated in FIG. 5A. The venture 22 tapers from a larger diameter into a smaller diameter to accelerate airflow velocity into the combustion chamber 9. The increased airflow will accelerate the ignition sequence within the combustion chamber 9.
The ventilator port may be formed at an angle to the combustion chamber. For example, illustrative embodiments show the ventilator port being formed perpendicular to the longitudinal axis of the combustion chamber and log billet. However, other angles may be used.
Embodiments of the ventilator port 11 comprise an adjustable gate 12 attached to an outer surface of the billet. The gate 12 may be attached with pin 13 formed from flammable or combustible material. The pin 13 attachment allows the gate 12 to swing over the ventilator port 11 in an adjustable manner to throttle airflow in to the combustion chamber 9. The adjustable ventilator gate 12 can be rotated across the mouth of the ventilator port to control air flow volume, thus reducing burn rate and temperature which will modulate burn time of the log stove. The adjustable ventilator gate 12 and attaching pins 13 may be constructed of material that will be consumed as the log billet 2 burns.
Embodiments of the log stove comprise intersecting, graduating slots 15 formed between the combustion chamber and an outside surface of the billet. In the illustrative embodiments, the slots are formed by two intersecting slots cut into the top surface of the billet. The slots preferably intersect at 90 degrees. However, other intersection angles may be used and more or fewer slots may be used. The slots are referred to herein as vari-vents. The slots may be formed by progressively narrower stepped cuts into the log billet from the top surface.
FIG. 13 shows an illustrative combustion diagram. Combustion is a chemical reaction of rapid oxidation started by the correct mixture of fuel, oxygen and an ignition source. The operating range and efficiency of a log stove may be established at an improved setting by maintaining controlled excess airflow. The airflow may be obtained by the use of a self-adjusting airflow to compensate with the biomass (wood) lost due to the burn rate.
The vari-vent described herein provides for an improved airflow. In one illustrative embodiment, the vari-vent consists of four slots cut on a quadrant layout extending into the combustion chamber 9, which is a vertical chamber, varying in diameter of one to two and one half inches and bored to a depth of approximately eleven inches. Each slot will have a top cavity 15A approximately one inch wide with the depth varying from one half inch to four inches, depending on log billet diameter. Extending down from the bottom of the one inch slot, a cut 15B varying in width between three eighths to one half inch will extend down the billet approximately four to seven inches. An advantage of this embodiment is that the flow of oxygen balances with the available remaining log mass as it burns.
The larger volume in the upper part of the vari-vent 15A cut out of this embodiment produces maximum airflow needed to produce ignition and fast prorogation of the flame front. The reduced volume in the lower section of the vari-vent 15B cut out will adjust the air flow as the burning expands the combustion chamber which maintains higher air flow that balances air flow (oxygen) to fuel ratios.
FIGS. 14-19 illustrate further embodiments of a fire stand. The fire stand may comprise a base assembly 30. Embodiments of the base assembly may include a base tube 32. The tube may extend around all or a portion of the base periphery. For example, as shown in FIG. 15, the base tube 32 extends around three sides of a generally square base. In other embodiments, the base may be round, triangular or some other shape.
The base assembly 30 may further comprise a base plate 34. The base plate may be welded to the base tube 32 or otherwise attached to fill an area within a periphery created by the base tube. The base plate 34 may include holes 58 or may be formed of expanded steel, mesh or other similar materials. Alternatively, the base plate may be steel or aluminum plate, including diamond plate. The base plate may serve a spark arresting function as well as providing a base for supporting the billet 2. The base assembly 30 may further comprise a base skirt 36 extending upwardly from the base plate 34. The base skirt may surround a lower portion of the billet 2 and may for a generally cylindrical cavity. The base skirt 36 may serve to contain and stabilize the billet as well as containing ashes generated as the billet burns.
A support tube 38 may extend upwardly from a portion of the base tube 32. A weld 40 may connect the support tube to the base tube. The support tube may comprise upper and lower parts connected by a slip joint 42 that comprises a tube having a larger diameter than the support tube. The slip joint may be positioned over a lower portion 38A of the support tube and attached thereto. An upper portion of the support tube 38B may then be removably inserted into the slip joint.
The support tube may provide support for a grill assembly. The grill assembly may comprise a grill skirt 46. The grill skirt may comprise a generally cylindrical side wall that may surround an upper end of billet 2. A grill plate 48 may be positioned to cover the top end of the grill skirt 46. The grill plate may include holes 60 or may be formed of expanded steel, mesh or other similar materials. Alternatively, the base plate may be steel or aluminum plate, including diamond plate. The grill plate 48 may be attached to the grill skirt 46 by a weld 50 or by other means including, but not limited to adhesive, fasteners or other means. Alternatively, the grill plate and grill skirt may be integrally formed. The grill plate 48 may further comprise a diffuser 52 positioned generally in the center of the grill plate so that the diffuser is positioned above the combustion chamber exhaust port 14. The diffuser may serve to deflect the exhaust gasses or to diffuse the heat generated by burning the billet across a larger area of the grill plate 48.
The grill assembly may be attached to the support tube 38 by a grill lock 44. The grill lock 44 may comprise a tube that fits over the support tube for slidable movement relative to the support tube. An extension arm 54 may connect the grill skirt 46 to the grill lock 44. The grill skirt, extension arm and grill lock may be connected by welds, fasteners or other attachment means. The grill lock may further comprise a locking mechanism 56. In the illustrated embodiments, the locking mechanism 56 is shown as a bolt that is inserted through a threaded hole in the grill lock 44 so that an end of the bolt can be tightened against an outside surface of the support tube. In this manner, the grill assembly can be positioned vertically and locked into place. In certain embodiments, the grill assembly is locked into place at a vertical distance from the base assembly such that the grill plate 48 is suspended some distance above a top surface of the billet 2 and the grill skirt 46 at least partially surrounds an upper end of the billet 2.

Claims

We claim:

1. A log stove compromising a log billet of combustible wood having a longitudinal axis, the log billet comprising:

a combustion chamber extending into a top surface of the log billet substantially parallel to the longitudinal axis of the log billet, the combustion chamber comprising a generally cylindrical sidewall, a closed lower end and an open upper end;

a ventilator port comprising a passageway extending into the log billet from an outside surface of the log billet such that the ventilator port intersects the combustion chamber; and

a slot cut into the log billet, the slot extending transversely through the log billet from the outside surface of the log billet to the combustion chamber side wall, the slot comprising a upper end adjacent the top surface of the log billet and a lower end spaced apart from the top surface of the log billet, wherein the slot upper end has a first width and the slot lower end has a second width less than the first width;

wherein the width of the slot upper end is less than a diameter of the combustion chamber.

2. The log stove of claim 1 wherein the open upper end of the combustion chamber forms an exhaust port.

3. The log stove of claim 1 wherein the ventilator port has an axis that is perpendicular to a central axis of the combustion chamber.

4. The log stove of claim 1 wherein the ventilator port has a substantially cylindrical shape.

5. The log stove of claim 4 wherein the ventilator port has a substantially constant diameter.

6. The log stove of claim 1 wherein the ventilator port comprises a tapered hole.

7. The log stove of claim 6 wherein the ventilator port has a first diameter adjacent to log billet outside surface and a second diameter adjacent to the combustion chamber sidewall.

8. The log stove of claim 7 wherein the first ventilator port diameter is larger than the second ventilator port diameter.

9. The log stove of claim 1 wherein the ventilator port further comprises a gate.

10. The log stove of claim 9 wherein the gate is attached to the outside surface of the log billet.

11. The log stove of claim 9 wherein the gate is adjustable to adjust an opening size of the ventilator port.

12. The log stove of claim 9 wherein the gate comprises a combustible material.

13. The log stove of claim 10 wherein the gate further comprises a pin attaching the gate to the outside surface of the log billet.

14. The log stove of claim 13 wherein the pin comprises a combustible material.

15. The log stove of claim 1 wherein the slot has a first portion having a first constant width extending from the log billet top surface to a distance between the slot upper end and the slot lower end, and the slot has a second portion having a second constant width smaller than the first constant width, the second portion extending a remaining distance to the slot lower end.

16. The log stove of claim 1 wherein the slot is substantially perpendicular to the combustion chamber sidewall.

17. The log stove of claim 1 further comprising a second slot extending from the combustion chamber sidewall substantially opposite the first slot.

18. The log stove of claim 17 wherein the second slot extends substantially parallel to the first slot.

19. The log stove of claim 18 further comprising third and fourth slots.

20. The log stove of claim 19 wherein the third and fourth slots extend substantially perpendicular to the first slot.