Title:
Alcohol gel fireplace burner
Kind Code:
A1


Abstract:
A self-regulating, fuel efficient, alcohol gel fireplace burner mechanism. The mechanism consists of: (1) a noncombustible logset that simulates the appearance of a series of logs and which has a cavity that accepts a cartridge of alcohol gel fuel, and (2) a specifically designed fireplace fuel cartridge containing such fuel. The interaction of the logset and the fuel cartridge produces a “fireplace-type fire” that is yellow-orange, flutters randomly at heights 3″-6″ above the logset logset, peaks at 8″-10″ or higher above the logset, and burns for 2 hours or more. The invention does not waste fuel by burning it in several round cans while attempting to create a rectangular fire, but instead uses a single fuel cartridge that produces a rectangular flame. The invention does not waste fuel by burning same to produce flames that are hidden, but instead allows all of the flames to be seen. The invention does not require rectangular holding boxes, damper lids or other manually operated fire control mechanisms because the invention self-regulates the flutter, peaking and size of the fire.



Inventors:
Weinberger, Michael (New York City, NY, US)
Application Number:
11/099937
Publication Date:
08/18/2005
Filing Date:
04/06/2005
Assignee:
WEINBERGER MICHAEL
Primary Class:
Other Classes:
126/512, 431/125, 126/43
International Classes:
F23C1/00; F24C3/00; F24C5/00; (IPC1-7): F24C5/00; F23C1/00; F24C3/00
View Patent Images:



Primary Examiner:
PRICE, CARL D
Attorney, Agent or Firm:
Michael Weinberger (827 Port Street, New Orleans, LA, 70117, US)
Claims:
1. A device for creating a fire display in a fireplace, comprising: a. a noncombustible logset having a substantially rectangular shape and having an internal cavity communicating with an opening on a top surface of said of said noncombustible logset, and b. a rectangular fuel cartridge located in said internal cavity of said noncombustible logset and a top opening of said fuel cartridge being aligned with said opening in said top surface of said noncombustible logset.

2. A device according to claim 1, wherein said fuel cartridge contains alcohol gel.

3. A device according to claim 1, wherein said internal cavity of said noncombustible logset has enough space to permit air movement around said fuel cartridge.

4. A device according to claim 2, wherein an aperture is formed in an outer wall of said noncombustible logset to permit a flow of air between said internal cavity of said noncombustible logset and the atmosphere.

5. A device according to claim 1, wherein said noncombustible logset has the appearance of a series of logs.

6. A device according to claim 1, wherein the depth and width of said internal cavity and said opening on a top surface of said noncombustible logset are slightly larger than the depth and width of said fuel cartridge.

7. A device according to claim 1, wherein said fuel cartridge includes tapered sidewalls and a bottom surface of said fuel cartridge has a smaller area than said top surface of said fuel cartridge.

8. A device according to claim 7, wherein the interior depth of said fuel cartridge is between substantially 1.8 and substantially 2.5 inches.

9. A device according to claim 1, wherein said fuel cartridge has an internal height between substantially 2.5 and substantially 3.5 inches, and an internal depth between substantially 1.8 and substantially 2.5 inches, and said top opening of said fuel cartridge has a depth between substantially 0.8 and substantially 1.3 inches and said top opening of said fuel cartridge is between 80% and 95% of the width of said fuel cartridge.

10. A device according to claim 2, wherein said fuel cartridge has an internal height between substantially 2.5 and substantially 3.5 inches, and an internal depth between substantially 1.8 and substantially 2.5 inches, and said top opening of said fuel cartridge has a depth between substantially 0.8 and 1.3 inches and said top opening of said fuel cartridge is between 80% and 95% of the width of said fuel cartridge.

11. A device according to claim 3, wherein said fuel cartridge has an internal height between substantially 2.5 and substantially 3.5 inches and an internal depth between substantially 1.8 and substantially 2.5 inches, and said top opening of said fuel cartridge has a depth between substantially 0.8 and substantially 1.3 inches and said top opening of said fuel cartridge is between 80% and 95% of the width of said fuel cartridge.

12. A device according to claim 4, wherein said fuel cartridge has an internal height between substantially 2.5 and substantially 3.5 inches, and an internal depth between substantially 1.8 and substantially 2.5 inches, and said top opening of said fuel cartridge has a depth between substantially 0.8 and substantially 1.3 inches and said top opening of said fuel cartridge is between 80% and 95% of the width of said fuel cartridge.

13. A device according to claim 5, wherein said fuel cartridge has an internal height between substantially 2.5 and substantially 3.5 inches, and an internal depth between substantially 1.8 and substantially 2.5 inches, and said top opening of said fuel cartridge has a depth between substantially 0.8 and substantially 1.3 inches and said top opening of said fuel cartridge is between 80% and 95% of the width of said fuel cartridge.

14. A device according to claim 6, wherein said fuel cartridge has an internal height between substantially 2.5 and substantially 3.5 inches, and an internal depth between substantially 1.8 and substantially 2.5 inches, and said top opening of said fuel cartridge has a depth between substantially 0.8 and substantially 1.3 inches and said top opening of said fuel cartridge is between 80% and 95% of the width of said fuel cartridge.

15. A device according to claim 7, wherein said fuel cartridge has an internal height between substantially 2.5 and substantially 3.5 inches, and an internal depth between substantially 1.8 and substantially 2.5 inches, and said top opening of said fuel cartridge has a depth between substantially 0.8 and substantially 1.3 inches and said top opening of said fuel cartridge is between 80% and 95% of the width of said fuel cartridge.

16. A device according to claim 1, further comprising an absorbent non-flammable liner positioned at the bottom of said fuel cartridge and saturated with between 1-2 ounces of water for every 19 ounces of fuel contained in said fuel cartridge.

17. A device according to claim 1, wherein said noncombustible logset includes a plurality of internal cavities, and each internal cavity containing a respective fuel cartridge.

18. A device according to claim 17, wherein said noncombustible logset includes a large internal cavity that contains two or more fuel cartridges.

19. A noncombustible logset that gives the appearance of a series of logs and which has a frontwall, backwall, and a topwall, where the said topwall has a rectangular topwall aperture slightly larger in depth and width than the depth and width, respectively, of a rectangular alcohol gel fireplace fuel cartridge that can pass through the said rectangular topwall aperture, and where the topwall sits over a cavity that is substantially larger in width and depth than the width and depth, respectively, of the rectangular alcohol gel fireplace fuel cartridge that may be inserted into the said cavity through the topwall aperture, and where the said cavity under the topwall is large enough to permit substantial air movement around the sidewalls of the rectangular alcohol gel fireplace fuel cartridge, and where the said cavity communicates with the atmosphere.

20. The logset described in claim 19, with a cavity and topwall aperture large enough to accommodate two or more rectangular alcohol gel fireplace fuel cartridges.

21. The logset described in claim 19, with two cavities and two topwall apertures, each holding their respective fuel cartridges.

22. A fuel cartridge made of light gauge metal, substantially rectangular in shape, containing alcohol gel fuel, and comprising of a bottom, four sidewalls, and a top wall with at least one rectangular aperture in the topwall, where the interior height of the said substantially rectangular fuel cartridge may ranges from substantially 2.5″ to substantially 3.5″, where the interior depth of the said substantially rectangular fuel cartridge ranges from substantially 1.8″ to substantially 2.5″, where the substantially rectangular aperture(s) in the topwall of the said substantially rectangular fuel have a depth that ranges from 0.8″-1.3″, and where the substantially rectangular aperture(s) in the topwall of the said substantially rectangular fuel has a width that is, or totals, 80% -95% of the width of the substantially rectangular fuel cartridge.

Description:

BACKGROUND

Many consumers cannot afford the expense of installing a wood or gas fireplace in their homes. Nevertheless, they find the visual appearance of a fireplace pleasing. As a result, inexpensive, portable fireplaces that do not require chimneys have become popular. These fireplaces burn alcohol gel fuel in round cans. U.S. Pat. No. 4,838,781, to Fischer, shows a burner mechanism for such a fireplace, as does U.S. Pat. No. 4,573,905, to Myers.

These systems produce “fireplace-type fires” that: (1) are substantially rectangular, i.e., wider than they are deep, (2) are predominantly yellow-orange, (3) flutter randomly, and (4) peak randomly at heights above the flutter range.

Mechanisms that use round cans of fuel to produce such fires present problems, however. First, it is inconvenient to use multiple cans of fuel, as opposed to a single fuel cartridge. Second, round cans of fuel, by themselves, cannot produce rectangular fires. Third, these systems require rectangular holding boxes to hold the round cans of fuel. Fourth, some of these systems require damper lids over the rectangular holding boxes. And fifth, such systems do not self-regulate the size of the fire. Instead, they require manual operation of the damper lid to regulate the size of the fire.

In addition, these systems waste fuel by burning it in round cans while attempting to create a rectangular fire. For example, if a rectangularly shaped fire that is eight inches wide is desired, the current invention can produce this by using a single fuel cartridge with an aperture that is eight inches wide and one inch deep. This exposes and burns eight square inches of alcohol gel fuel. Two round cans of alcohol gel fuel placed next to one another, where each can has a four inch round aperture, can also arguably create an eight inch wide fire, but this fire exposes and burns over 25 square inches of alcohol gel fuel. This is more than three times the amount of fuel used by the current invention.

To date, developing a fuel efficient alcohol gel fireplace burner that uses a single, self regulating fuel cartridge that produces a “fireplace type fire” when used in conjunction with a non-combustible logset has been problematic. This is partially because of the large number of variables involved. For example, there are many types of alcohol gel fuels, and each burns differently. Methanol, for instance, is perfectly suited for traditional “STERNO”™ cans, but it produces a blue flame as opposed to a yellow-orange “fireplace-type fire”. Although this problem can be solved by adding salts to the burning methanol gel, the salts can destroy the functionality of the thickening agents in the gel. This can turn the gel into a liquid and defeats the gel's advantages, such as resistance to spillage and a slower burn rate.

Ethanol and isopropanol gels produce yellow flames when they burn, but plentiful amounts of ambient oxygen can cause these fuels to burn too quickly and can also produce fires that are too large. Conversely, insufficient oxygen can result in fires that are too small or self extinguish before all the fuel has burned. The prior art solved this problem by placing manually adjusted “damper lids” over the rectangular boxes that hold the round cans of fuel. Although this controlled the fire's size and burn rate, it did not produce a self-regulated fire. A self-regulated fire is more convenient than a fire that requires manually operated control mechanisms.

As Messina discusses in U.S. Pat. No. 5,584,283 for a “STERNO”™ type cartridge that produces a toroidally shaped cooking fire, regulating a fire coming from a fuel cartridge requires control over both fuel flow and oxygen flow. The flow of fuel vapor coming out of the cartridge, and the flow of ambient oxygen coming into the cartridge, must both be regulated. This is especially critical when designing a cartridge to produce a “fireplace-type fire” because it is much larger than a “STERNO”™ type fire. Moreover, a fireplace fire should last about two hours or more. Consumers do not want fireplace fires that burn for short periods of time. Hence, a fuel cartridge for a “fireplace-type fire” has to control fuel flow and oxygen flow very carefully.

In addition, a thorough study of the interplay between the cartridge and the non-combustible logset that is used with the cartridge must be undertaken. Consumers expect to see logs in a fireplace, even if they are fake. The fuel cartridge must work with the logset. This is another difference between a fireplace fuel cartridge and a “STERNO”™ type container. “STERNO”™ type containers are sometimes used freestanding, underneath a warming pan, or they are sometimes placed in small metal holding cups, but they are rarely placed inside logsets of any sort.

Because the fuel cartridge in the present invention is placed inside the logset, the logset affects oxygen flow near and around the cartridge. This affects how the cartridge performs and the type of fire it produces. In this regard, a distinction should be made between the present logset and a noncombustible log that is merely placed in front of a container of burning fuel.

Some alcohol gel fireplaces, for example, those sold by Jensen Metal Products of Racine, Wis., and 2Burn Inc. of West Allis, Wis., merely place a fake log in front of several round containers of fuel. This fake log does not surround the fuel containers and it does not appear to affect how the fuel in the containers burns. Indeed, the containers themselves do not appear to have any special design features. They appear to be paint cans.

By way of contrast, the present logset surrounds the fuel cartridge, which is a specially designed component, not a paint can. The top of the logset and the cavity in the middle of the logset both affect airflow in numerous ways. Control of this airflow is critical.

For example, the logset must restrict oxygen flow that originates adjacent to the sidewalls of the fuel cartridge and then continues up and over the top of the cartridge. If this is not restricted an “upward draft effect”, as shown in FIG. 9, can result. This can prevent random fluttering of the fire and instead produce a static, triangularly shaped fire. See FIG. 9.

In addition, the logset must allow substantial air movement around the cartridge's sidewalls. Again, that is because this cartridge is entirely different from a “STERNO”™ type cartridge that can sit snugly in a metal cup and requires no substantial air flow around the sidewalls of the cartridge.

Because this cartridge produces a much larger fire than that produced by a “STERNO˜™ container it produces much more heat. If the sidewalls are made of light gauge metal, versus ⅛″ steel plate which acts as a heat sink, the light gauge metal in the sidewall which contacts the fuel can get very hot. As a result, it needs to be substantially ventilated. This can be done by designing the logset so that air circulates around the sidewalls of the cartridge, and by permitting communication between this air and ambient room air. If this is not accomplished the extremely hot sidewalls of the cartridge can transfer heat back to the fuel remaining in the cartridge. This can actually cause large amounts of fuel to boil. If this happens the remaining fuel will burn at a much faster rate, which, in turn, will produce yet more heat. In turn, this will cause yet more fuel to boil, causing more heat, and so on. This can cause a fire that flutters at 3″-6″, peaks at 8″-10″+, and burns for over two hours, for example, to flutter at 8″, peak at 14″+, and burn for less than 90 minutes.

Studies were conducted on various fuel cartridge and logset designs to solve these problems. Cartridges were studied that were made out of ⅛″ steel plate, 1/16″ steel plate, aluminum, and light gauge steel. A variety of cartridge shapes were studied, including rectangles that were 2″, 4″, 6″ and up to 10.5″ wide, as well as other widths. Various cartridge heights were studied, ranging from about 2″ to 5″. Different cartridge depths were tested that ranged from about 1.5″ to over 4″. Cartridge sidewalls were sometimes perpendicular to the cartridge's base and sometimes tapered outwardly from the base at about a 100 degree angle. Cartridges with square corners and rounded corners were examined. Cartridges containing various gel fuels were tested, including mixtures that used different thickening agents and mixtures that contained varying percentages of water. Cartridges that had hydrated absorbent liners on the bottom of the cartridge were studied in order to slow the burn rate of various fuels and to prevent the residue of various thickening agents from catching fire due to excessive heat. Cartridges held in heat sinks that absorbed part of the heat generated by the burning fuel were studied. Different heat sinks were tested, as were heat sinks that used a water jacket between the heat sink and the fuel cartridge. Cartridges with one, two, and up to five apertures on top were compared. Differently shaped apertures were tested, such as rectangular, circular, and square shaped apertures, and others. Cartridges that had fully open tops were studied and compared to cartridges that had metal topwalls with apertures that controlled vapor flow. Apertures of different widths and depths were studied, and sometimes differently shaped apertures were placed on top of a single cartridge.

Noncombustible logsets that were cast as a single piece were examined, as were multi-piece logsets. Logsets that partially sat over the burning fuel were studied, as were logsets that surrounded the fuel cartridge but did not sit directly over it. Logsets that held fuel cartridges snugly were studied, as were logsets that did not hold cartridges snugly. Logsets that permitted substantial air circulation around the sidewalls of the cartridge were examined, as were logsets that did not. Logsets that permitted substantial air movement that originated adjacent to the sidewalls of the cartridge and then continued up and over the top of the cartridge were studied, as were logsets that did not. Logsets that allowed air that circulated around the sidewalls of a fuel cartridge to communicate with ambient room air were studied, as were logsets that did not permit such communication. Many other logset designs were also examined.

The result of this work is the current invention, specifically, an alcohol gel fireplace burner system that uses a specifically designed single fuel cartridge, sitting in a specifically designed noncombustible logset, to produce a fuel efficient, self regulating, rectangularly shaped, “fireplace type fire” that appears to rise from a series of logs and twigs.

DISADVANTAGES OF THE PRIOR ART

The applicant is not aware of a fireplace burner mechanism that accomplishes the goals of the current invention.

U.S. Pat. No. 4,838,781, to Fischer, for example, shows a system that uses four round cans of alcohol gel fuel sitting in a rectangular metal holding box. The rectangular holding box has a manually operated lid that sits over the box and regulates the burn rate of the fuel and the size of the fire.

U.S. Pat. No. 4,573,905, to Meyers, also shows a system that uses multiple round cans of alcohol gel fuel in a metal holding box. Myers' next attempt, U.S. Pat. No. 4,890,600, also shows a rectangular box holding multiple cans of fuel.

Hilker, in U.S. Pat. No. 4,076,490, discloses a noncombustible log that holds three round cans of fuel and produces three round fires. Hiker's invention does not produce a rectangularly shaped fire. Nor does Hiker disclose a single, self regulating, fuel cartridge. Nor does Hiker's invention produce a fire that appears to rise from a series of logs and twigs, as opposed to a single log. Nor does Hiker ventilate the sidewalls of the three round cans of fuel.

Orlov, in U.S. Pat. No. 5,026,271, discloses a burner mechanism that can use alcohol gel, but Orlov does not disclose a noncombustible logset with a rectangular cavity that holds a fuel cartridge. Instead, Orlov shows a group of logs placed over a fuel source. This produces soot. Additionally, Orlov's invention does not self regulate the size and burn rate of the fire but instead requires a manually adjusted snuffer plate and aperture plate. Moreover, Orlov's invention is fuel inefficient. It wastes fuel by burning same to produce flames that are hidden underneath his logs.

U.S. Pat. No. 3,993,430 to Forker, U.S. Pat. No. 4,582,478 to Hiker, and U.S. Pat. No. 4,637,372 to Mogol reveal burner systems that employ liquid fuel, such as “fuel oil” (see Forker's Abstract), as opposed to alcohol gel fuel in a cartridge. A system that burns liquid fuel is different from a system that burns gelled alcohol in a cartridge. For example, liquid fuel systems may require pipes and tubes. See the pipe 22 in Hiker, and the tube 14 in Mogol. Other liquid fuel systems, like Forker's, require sand and vermiculite to absorb the liquid fuel. These systems do not disclose the present invention.

Nor does the prior art in fuel cartridges reveal the present invention. For example, U.S. Pat. No. 5,584,283, to Messina, discloses a “STERNO”™ type fuel cartridge that produces a static, toroidally shaped fire. Messina's fire is used for cooking. Messina does not disclose a self regulating, rectangular, “fireplace-type fire” that flutters and peaks within a predictable range of heights when used with a non-combustible logset. A “STERNO”™ cartridge that produces a small flame that is used for cooking, which is hidden underneath a pan, works very differently from a fireplace cartridge that creates a larger, visual effect.

Other fuel cartridge patents disclose different types of fuel cartridges used for a variety of purposes. For example, U.S. Pat. No. 5,062,222, to Billet, et al., describes a fuel cartridge that heats a ski boot. U.S. Pat. No. 4,084,086, to Bandel, describes a fuel cartridge containing solid fuel used to illuminate a lamp. U.S. Pat. No. 4,896,653, to Eke, et al., describes another round, “STERNO”™ type can used for cooking. None of these patents disclose the present invention.

OBJECTS AND ADVANTAGES

The objects and advantages of the present invention are to provide an alcohol gel fireplace burner mechanism that uses a single fuel cartridge and a noncombustible logset to produce a self-regulating, fuel efficient, rectangularly shaped, “fireplace type fire” that appears to rise from a series of logs and twigs.

SUMMARY

In accordance with the present invention, there is provided a noncombustible logset that simulates the appearance of a series of logs but which may be cast as a unitary item. The logset has a cavity that accepts a single cartridge of alcohol gel fuel. The logset is placed inside a fireplace.

The logset controls airflow around the fuel cartridge in three ways. First, it limits airflow that originates from the area immediately adjacent to the sidewalls of fuel cartridge and then continues over the top of the cartridge. This prevents the fire emanating from the fuel cartridge from becoming triangularly shaped. It also enhances the fire's ability to flutter.

Second, the logset permits substantial air movement around the sidewalls of the fuel cartridge. Third, it permits substantial communication of the air moving around the sidewalls of the cartridge with ambient room air. This ventilates the sidewalls of the fuel cartridge.

The fuel cartridge holds an alcohol gel mixture containing isopropanol and/or ethanol, as opposed to methanol, which is used in many “STERNO”™ type fuel cartridges. The fuel cartridge shapes the fire into a rectangular pattern, as opposed to a round “STERNO˜™ type pattern or a toroidal pattern.

The fuel cartridge contains a specifically designed top aperture which controls the flow of fuel vapor out of the cartridge, as well as the flow of ambient oxygen into the cartridge. When used in conjunction with the logset, the fuel cartridge self-regulates the flutter, peaking, and size of the fire without the use of manually operated fire control mechanisms. The fire will flutter approximately 3″ to 6″ in height. The fire will peak at heights of 8″ to 10″ or higher. The fire will burn for about two hours or more.

The fire will appear to rise from a group of logs and twigs because the cavity in the logset that accepts the fuel cartridge places the point of origin of the fire slightly lower than the logs that are immediately adjacent thereto. This creates the appearance of a fire that rises from underneath a pile of logs, which is preferred, but it does not produce the very small amount of soot that can result from placing logs immediately over the burning alcohol gel fuel.

DRAWING—FIGURES

FIG. 1 shows the fuel cartridge, the logset and the logset's cavity that accepts the fuel cartridge.

FIG. 2 is a side view of the logset.

FIG. 3 shows the rear wall of the logset and the rear wall aperture.

FIG. 4 shows the logset with the fuel cartridge sitting in the logset's cavity. Line 5 is a reference point for a cross sectional view.

FIG. 5 is a cross sectional view taken along Line 5 of FIG. 4, showing the fuel cartridge sitting in the logset's cavity.

FIG. 6 shows the logset with the fuel cartridge sitting in the logset's cavity, with Line 7 as a reference point for a cross sectional view.

FIG. 7 is a cross sectional view taken along Line 7 of FIG. 6, showing the fuel cartridge in the logset's cavity and the rear wall aperture.

FIG. 8 shows a fluttering fire emanating from the fuel cartridge sitting in the logset.

FIG. 9 does not show the present invention but is provided for illustrative purposes. It shows a triangularly shaped fire surrounded by upward air drafts that emanate from holes in the top of the logset that are adjacent to the fuel cartridge.

FIG. 10 shows one embodiment of a fuel cartridge, where H represents the cartridge's height, W represents its width, D represents its width, AD represents the depth of the rectangular aperture on the top of this cartridge and AW represents the width of the aperture on top of this cartridge.

DRAWINGS—REFERENCE NUMERALS

  • 1 Invention
  • 2 Logset
  • 5 Fuel cartridge
  • 5A Cartridge sidewall
  • 5B Cartridge topwall
  • 5C Cartridge aperture
  • 7 Fluttering fire
  • 8 Upward air draft
  • 9 Triangular fire
  • 10 Top of backwall
  • 11 Topwall
  • 12 Frontwall
  • 13 Opening
  • 14 Sidewall
  • 15 Rear of backwall
  • 16 Backwall aperture
  • 17 Cavity

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT

The presently preferred embodiment of the invention is illustrated in FIGS. 1-8 and 10. FIG. 9 does not show the invention but has been included for illustrative purposes.

FIG. 1 shows a logset 2 cast out of ceramic or other noncombustible material. The logset 2 gives the appearance of a series of logs and twigs but may be cast as a unitary piece. The logset 2 has an opening 13 in its topwall 11 which communicates with the atmosphere and accepts a fuel cartridge 5. Additional but smaller openings in the topwall are possible, as long as they do not create a large updraft next to the cartridge.

FIG. 2 is a side view of the logset 2 showing one sidewall 14. The purpose of the sidewall 14 is to help support the logset 2 and to hide the fuel cartridge 5. The sidewall 14 does not need to be a solid wall and it may have openings in it for air circulation. FIG. 3 shows the rear of the backwall 15 and the backwall aperture 16. The backwall aperture 16 permits ambient room air to move freely into the cavity 17 of the logset 2.

FIGS. 4-7 show the relative positions of the fuel cartridge 5 and different portions of the logset 2, such as the cavity 17. Note that the cavity 17 is substantially larger than the fuel cartridge 5. This ventilates the sidewalls 5A of the cartridge 5 to prevent overheating. Note also that the topwall 5B of the cartridge 5 is slightly lower than the topwall 11 of the logset 2. This is not essential to the invention, but it permits fire 7 from the fuel cartridge 5 to originate from a point slightly lower than the topwall 11 of the logset 2, thereby giving the appearance of a fire 7 that rises from underneath a group of logs.

FIG. 8 shows a fluttering fire 7 emanating from the fuel cartridge 5 sitting in the cavity 17 of the logset 2. This fluttering fire 7 may be contrasted with the triangularly shaped fire 9 shown for illustrative purposes in FIG. 9, which does not show the current invention because the topwall in this figure has large holes that allow an upward air draft 8 next to the cartridge. Since one purpose of the invention is to provide a fluttering fire, as opposed to a static triangularly shaped fire, holes in the topwall of the logset that result in air drafts which prevent the fire from fluttering should be avoided.

The fuel cartridge 5 used with the logset 2 is shown in FIG. 10 and may be made out of a light gauge metal. The closure for the fuel cartridge is not shown because it may take various forms, such as a plug lid or a “peel off” top, as is commonly known among those skilled in the art of making closures for containers. The cartridge 5 and its top aperture 5C should be generally rectangular, but do not have to be perfect rectangles. In addition, both the cartridge 5 and its aperture 5C may have slightly rounded corners.

Specific measurements and ratios are employed on the cartridge 5 and its aperture 5C for the cartridge to function properly. These measurements and ratios are required to: (1) Control the flow of fuel vapor out of the cartridge; (2) Control the flow of ambient oxygen into the cartridge; (3) Self-regulate the fire's flutter so that it ranges from about 3″ to 6″ above the logset; (4) Self regulate the fire's peaks so that they range from about 8″ to 10″, or higher, above the logset; (5) Self regulate the fire's burn time so that it lasts about two hours or longer.

The measurements are represented by the letters “H”, “W”, “D”, “AD”, and “AW” in FIG. 10. “H” refers to interior cartridge height. “W” refers to interior cartridge width. “D” refers to interior cartridge depth. “AD” refers to the depth of the cartridge aperture, and “AW” refers to the width of the cartridge aperture. In the presently preferred embodiment, the sizes and ratios that need to be employed are listed below:

TABLE OF MEASUREMENTS AND RATIOS
Hinterior cartridge height2.5″-3.5″
Winterior cartridge widthabout 30%-50% of logset's width
Dinterior cartridge depth1.8″-2.5″
ADaperture depth0.8″-1.3″
AWaperture width80%-95% of “W”

The cartridge is filled with an isopropanol and/or ethanol based gel, as opposed to a methanol based gel. As discussed by Browning, in U.S. Pat. No. 4,575,379, and by Messina, in U.S. Pat. No. 5,584,283, different gels can be made by using different thickening agents. Commercially available gels also exist and are sold under names like “REALFLAME”™ or “SUNJEL”™.

The cartridge should be substantially filled with gel, but not entirely filled so that gel touches the topwall 5B. It is better to have a small air gap between the top layer of gel and the topwall 5B. This air gap may be, for example 0.1″. The presence of this air gap allows more gel to contact ambient room air, so that more alcohol vapors are released.

If this air gap is not present less alcohol vapors will be released during the initial stages of the burn cycle. This may result in a much smaller fire. This condition will continue until enough gel is burned so that the top layer of gel is under the topwall 5B.

After ignition, the cartridge self-regulates the flutter, peaking and size of the fire through: (1) the interaction of the specified measurements of H, W, D, AD and AW, and (2) the interaction between the cartridge and the logset.

If substantial deviations are made from the measurements specified herein the cartridge will not function properly. For example, aperture depth, AD, should range from 0.8″-1.3″, depending on the thickness of the gel.

Thicker gels generally release alcohol vapors slower than thinner gels with the same percentage of alcohol content. Hence, thicker gels require greater aperture widths than thinner gels require to release enough alcohol vapors to produce a desirable fire. A thicker gel may require an aperture depth of 1.3″ to produce a fire that peaks at 8″ and burns for about 2 hours, whereas a thinner gel may only require an aperture depth of 0.8″.

Aperture depths have maximum ranges as well. As a general rule, they should not exceed 1.3″. If aperture depth is 1.6″, for example, more fuel vapors will leave the cartridge than are required to produce a visually appealing fire and the cartridge will burn too quickly. In other words, too much fuel will be burned, creating a fire that is larger than it needs to be, but which does not last as long as it should. This wastes fuel.

Interior cartridge height should be 2.5″-3.5″. This enables the cartridge to hold enough fuel to burn for about 2 hours or more. As cartridge height increases, however, it becomes more difficult for ambient oxygen to enter the cartridge and mix properly with fuel vapors. If cartridge height is too tall, for example, 5″ not enough oxygen will be able to enter the cartridge and reach the bottom layers of gel fuel. If this happens the cartridge may self extinguish or produce a very small flame.

Cartridge width, however, may vary. Cartridges of very different widths can still operate properly. Cartridge width needs to be large enough, however, to create a visually pleasing fire. This is largely a function of the width of the logset used in the fireplace.

As a general rule, a visually pleasing fire may rise from about the middle third or the middle half of the logset, although it can be larger. The width of the fuel cartridge, and the width of the aperture on top of the cartridge, therefore, needs to be large enough to produce such a fire.

For example, if the logset is 18 inches wide the fire may rise from about the middle six inches thereof. This would leave about six inches of logs that appear to be “not burning yet” to the left of the fire and another six inches of logs that are also “not burning yet” to the right of the fire.

To produce a fire that is about six inches wide, for example, the cartridge has to be wide enough to accommodate an aperture that is almost six inches wide. The aperture does not have to be exactly six inches wide because the fire will sometimes flare out, to the left and right of the aperture, as shown in FIG. 8. Hence, a cartridge aperture that is 5.5″ wide can produce a fire that flares to 6″ widths. A cartridge aperture that is 5.5″ wide may be placed on top of a cartridge that is about 6″-7″ wide, depending on the type of closure system used to seal the top of the cartridge.

If the measurements and ratios listed herein are followed, and the cartridge is used in conjunction with the specified logset, a visually appealing fire can be created that makes very efficient use of fuel. One reason fuel use is efficient is because the cartridge uses a rectangular aperture to create a rectangular fire. The invention does not use round “paint cans” of fuel in a rectangular holding box, as the prior art does.

Another reason why fuel use is efficient is because substantially all of the fire created by burning fuel is visible. It is wasteful to burn fuel to create a fire that cannot be seen, although that is what many existing systems do.

For example, the systems sold by Jensen Metal Products of Racine, Wis. and by 2Burn, Inc. of West Allis, Wis. employ two-three “paint cans” filled with fuel that are placed behind a fake log. The logs, which are similar to small walls, are about 7″-7.5″ high, with some points higher than others. The “paint cans” of fuel behind the log, however, are about 3.75″ high. Hence, the logs hide a substantial portion of the fire. During some stages of the burn cycle, when the fire coming out of the cans is 6″ high, the log can hide 40%-50% of the fire. During the latter stages of the burn cycle, when the fire coming from the cans can be 3″ high, the log can hide the entire flame.

Yet, the primary function of such an alcohol gel fireplace is to provide a visual effect. Each “paint can” of fuel only produces about 3,000 btu's of heat per hour, which is not enough to heat a house. This may be compared with a traditional wood or gas fired fireplace, which can produce 30,000 to 40,000 btu's of heat. Since the production of a visual effect is the primary function of an alcohol gel fireplace, burning fuel to create a fire that cannot be seen is wasteful. The present invention does not wate fuel like this.

Operation

To operate the invention the fuel cartridge is opened and placed in the cavity of the logset. The fuel is then ignited. The invention will self regulate the flutter, peaks and size of the fire. Manually operated adjustment mechanisms that regulate the size of the fire are not employed.

Alternative Embodiments

Although the use of one fuel cartridge is more convenient, cost or size considerations may sometimes make the use of two cartridges desirable. In that case the logset may contain two apertures and accept two fuel cartridges.

The sidewalls of the fuel cartridge may be tapered, so that the bottom of the cartridge has less depth than the top. In that case the top width of the cartridge may be up to 3″.

The fuel cartridge may have more than one generally rectangular aperture, as long as the depth of the apertures is within the range specified herein and if their total width is approximately 80%-95% of the width of the cartridge. Note, however, that fuel cartridges with more than one aperture can experience substantial amounts of “Crust Burn”, which refers to the burning of the crust residue left by some thickening agents in some alcohol gel fuels. Substantial amounts of “Crust Burn” can cause unpleasant odors, and hence, this requires a solution, as explained below.

Experience indicates that alcohol gel fuel burned in a rectangular fuel cartridge burns very differently from the same fuel burning in a round, “STERNO”™ container or in a “paint can”. For example, gel fuel in a rectangular cartridge rarely burns at a perfectly even rate on both the right and left sides of the cartridge. One side usually burns a bit faster than the other, even if the difference is only 1%. It is unclear why this happens, although it may be related to such mundane factors such as ambient air movement in the room, as people walk about.

If the fuel cartridge only has one aperture “Crust Burn”, if it is experienced at all, is usually minimal. Depending on the type of gel fuel used, sometimes a small amount of smoke may be produced when the cartridge goes out, but this may be similar to the amount of smoke created when one blows out, for example, three candles on a candelabra.

On the other hand, if the fuel cartridge has more than one aperture, there is a better chance that substantial amounts of “Crust Burn” may be experienced at the end of the burn cycle, depending on the amount and type of thickening agents in the fuel formula. This appears to be caused by what the inventor calls the “Bellows Effect.”

The “Bellows Effect” refers to the situation that takes place when one side of the aperture on top of the rectangular fireplace fuel cartridge turns into a 100% air intake, feeding large amounts of air to the opposite end of the fuel cartridge. In the experience of this inventor, this happens more frequently with fireplace fuel cartridges that have multiple apertures, versus fireplace cartridges that have only one aperture. One may note that this is yet another difference between the present invention and traditional “STERNO”™ cans. Although “Crust Burn” has been encountered while developing this invention, this inventor has never observed “Crust Burn” in a traditional, round, “STERNO”™ can with a traditional round aperture.

In a rectangular fireplace fuel cartridge with left and right side apertures, for example, the fuel may burn 1% faster on the right side than on the left side. In that case, at the end of the burn cycle the right side may be out of fuel, whereas the left side will still have fuel. At that point the “Bellows Effect” may feed an over-abundance of oxygen to the fuel remaining on the left side. This causes the remaining fuel to burn hotter than it ordinarily would have.

This extra heat may not be a problem if the cartridge is made out of a a heavy gauge metal, because the extra heat can be absorbed by the mass of heavy metal, which acts as a heat sink. Cartridges made out of ⅛″steel plate, for example, can act as heat sinks. Because they absorb the extra heat they usually do not transfer large amounts of heat to the crust residue that remains in the cartridge. Hence, cartridges made out of ⅛″ steel plate usually do not experience substantial amounts of “Crust Burn”.

If the cartridge is made out of a light gauge metal, however, as is specified here, the extra heat can be transferred to the crust. This appears to be the cause of “Crust Burn”.

One way to eliminate or minimize “Crust Burn” is to lower the amount of thickening agents in the gel. This lowers the amount of crust formation and lowers the possibility of “Crust Burn”. Another way to do this is to cool off the cartridge during the last stages of the burn cycle, which is when the “Bellows Effect” has been observed. This can be done by lining the bottom of the cartridge with a nonflammable liner soaked in water. A bottom liner holding 1-2 ounces of water for every 19 ounces of gel fuel in the cartridge may be used for this purpose.





 
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