The invention relates to fuel burners and more specifically systems for burning solid fuels.
Typically wax is used as a fuel in traditional candles. Traditional candles transfer heat to melt the wax around a wick via radiation. The process delivers heat slowly and inefficiently resulting in a slow rate of melting the wax around the wick and creating the melt pool. Performance candles, candles that are used to drive a volatile active ingredient into the air, rely on developing a melt pool since the rate of active delivery is dependent on the size or surface area of the pool. Traditional candles can take four or more hours to create a melt pool of sufficient size to fill a typical room or area with its volatile active ingredient.
At the same time, because the flame size is limited and the resulting heat flux generated by the flame so small, the operating temperature of a candle melt pool is barely above the melt temperature of the wax, which limits the rate and the completeness of the volatile chemical delivery and limits the pallet of active ingredients that can be functional to those that work at lower temperatures.
Because of the small flame, slow melt pool development, and low operating temperature of the melt pool, performance candles suffer from sluggish and incomplete delivery. Performance candle formulators (like perfumers) are restricted to a limited breadth of ingredients that can be effectively used.
Further, traditional candles have flame sizes that are greatly limited. Candles used indoors are limited in size and in heat of the flame due to the creation of soot as the candle/wick system increases in size. As such products move outdoors, where soot can be accommodated, larger flames become increasingly difficult to create because larger wicks become difficult to ignite. This is due to the overall mass and heat capacity of the wick and wax, which makes it difficult or impossible to vaporize the fuel for ignition.
Indoor or traditional candle type products are therefore limited in flame size and heat delivery. The indoor use of candles can be used for lighting as well as delivery of a volatile active ingredient like fragrance, medicinal ingredients, or insect repellent (if used outdoors). Unfortunately, the flame size and heat limitations of the traditional wick and wax systems result in products that create low light and take exceptionally long times for the melt pool to develop. Since the active delivery is a function of both the wax/fuel melt pool size and operating temperature, the volatile active ingredient is slow to release and to be delivered to the surroundings. Even the Glade™ Scented Oil Candle that uses metal fins within the flame takes almost an hour to create a melt pool. In the outdoor use environment, this melt pool issue is exacerbated because of cooler air temperatures or the cooling effects of breezes.
Outdoor products rely on more flammable fuels like mineral oils or alcohols. Alcohol fuels like ethanol, isopropyl alcohol, and other short chain alcohols have recently been recalled due to their extreme flammability and ability to carry the fire without a wick. Mineral oil type fuels, like those used in yard torches, are acutely toxic to the respiratory system upon even the slightest ingestion. In addition, the liquid fuels are prone to creating excessive soot and develop and deliver an oil refinery off odor.
The present inventor has recognized that waxes, including but not limited to paraffin, soy wax, palm wax, beeswax, and others, would make ideal fuels, especially for outdoor products that desire and require larger flames. Additionally, the present inventor has recognized that indoor applications could benefit from both light intensity improvements as well as faster wax pool development. The present inventor recognizes the need for a device that allows for faster wax pool melting and increased heat production.
Still Further, wicks or wick material often function as a filter and, like filters, are prone to fouling or clogging resulting from prolonged use or use with “dirty” filtrate (or fuel in the case of wicks). Most wicks are consumable and are not plagued by fouling or clogging; yet the phenomenon presents itself and can be dangerous as carbon pills form at the end of consumable wicks.
The present inventor has recognized that the benefits of a reusable or permanent wick are many and varied and include, but are not limited to, flame control, flame staging, and, in some applications, creating flames of unique geometry, hotter flames, larger stable flames, and less soot. However, reusable wicks are prone to clogging or fouling by the fuel used—especially fuels that contain higher levels of longer chain hydrocarbons (products like waxes or paraffin). These kinds of fuel with repeated use can lead to build-up of varnish, tar, carbon deposits, and other materials that can prevent the liquid fuel from flowing through the wick material, which results in diminished performance (smaller flames) and ultimately complete failure. In effect, the chemical nature of hydrocarbon fuels and their natural inclusion of longer chain components (even at very low levels) has heretofore made using permanent or reusable wicks difficult or practically impossible.
The present inventor has recognized the need for a device that allows reusable or permanent wicks while diminishing or eliminating the cumulative effects of fouling or clogging caused by hydrocarbon fuels.
Moreover, the present inventor has recognized that unlike traditional candles with a consumable wick, reusable and permanent wick candles offer the user the option to make larger and more stable flames, to create wax burners that shed more light, to create candles that produce larger and warmer melt pools that in turn more effectively deliver a volatile ingredient to the environment, and to repeatedly operate the system with no waste.
However, since the reusable or permanent wick remains with the burner apparatus, consideration is needed for preparing the wick for reuse. The present inventor has recognized that when the wick is barren of any fuel, it may require priming. The present inventor has recognized that priming must be enough to allow easy ignition without taking too long to ignite or without flooding the point of ignition. Then that first ignition point must provide enough heat to the surrounding wax to stoke the developing flame without melting so much wax that the melted wax restricts or even douses the developing flame. The present inventor has recognized that an imbalance of both the priming and stoking stages of the developing flame can result in starving the flame or in partially or completely flooding the first ignition.
The present inventor has recognized the need for a solid fuel, such as solid wax structure that repeatedly and reliably offers a natural priming location for wick ignition and then automatically manages the stoking stage to allow uninhibited and full development of the desired flame. Finally, the present inventor recognized the need for a device that provides a main wax portion that is to be melted by the flame and used through complete melt and combustion.
A burn chamber system, a fuel burning system, and a method are disclosed. In some embodiments, the burn chamber system comprises a wick and a wick sheath. The wick has an at least partially hollow core forming a burn chamber. The wick sheath surrounds the wick. The wick sheath has a side wall having one or more wick sheath apertures in communication with the wick.
In some embodiments, the one or more wick sheath apertures are located on the top half of the side wall.
In some embodiments, the one or more wick sheath apertures are located on the top quarter of the side wall.
In some embodiments, the one or more wick sheath apertures are adjacent to a top edge of the wick sheath.
In some embodiments, the one or more wick sheath apertures comprise a plurality of apertures spaced apart equally about the side wall.
In some embodiments, the wick sheath is cylindrical and the wick is cylindrical.
In some embodiments, the one or more wick sheath apertures are ⅛ of an inch in diameter.
In some embodiments, the one or more wick sheath apertures are 1/16 of an inch in diameter.
In some embodiments, the wick comprises at least one of aluminum, copper, steel, iron, nickel, ceramic, stone, refractory materials, glass, or ceramic fiber paper.
In some embodiments, the burn chamber system has a wick support located within the at least partially hollow core.
In some embodiments, the fuel burning system comprises a melted wax reservoir, a melting grate, a wick, and a wick sheath. The melting grate is configured to receive a solid wax. The melting grate located above at least a portion of the melted wax reservoir so that wax melted on the melting grate can be received into the melted wax reservoir. The wick has an at least partially hollow core forming a burn chamber extending above the melting grate. The wick sheath surrounds the wick. The wick sheath has a side wall having one or more wick sheath apertures in communication with the wick.
In some embodiments, the method is a method of increasing oxygen delivery to a fuel burning system having an at least partially hollow core forming a burn chamber. A flame is ignited on the wick. Oxygen is supplied into the burn chamber to combine with a fuel by drawing air through one or more holes in a wick sheath, the wick sheath being adjacent the wick.
In some embodiments, air is drawn through the one or more holes in the wick sheath, through a porous side wall of the wick, and into the burn chamber.
Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings.
While this invention is susceptible of embodiment in many different forms, there are shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated.
System Overview.
In general operation, a solid fuel, such as solid fuel 201, is placed on the melting grate. The wick is lit and the resulting flame begins to heat the solid fuel causing it to melt. The melted fuel flows through the melting grate and into the fuel reservoir. The melted fuel is drawn into the wick to continue fueling the flame at the wick. The flame transmits heat to the solid fuel in at least two ways. First, heat from the flame is transmitted through the ambient air to the solid fuel. Second, heat is thermally transferred through the wick sheath and the melting grate to the fuel which is in contact with the melting grate. In some arrangements, wax may fall directly on the wick to prime the wick during initial operation until fuel is drawn into a bottom portion of the wick for feeding the flame at the top of the wick.
The reservoir 150 comprises a curved shape having a bottom 152 with upwardly curving sides 154, 156. The width of the melting grate 140 is sized to contact the sides 154, 156 of the bowl to position the bottom 148 of the melting grate 140 a pre-defined distance from the bottom of the reservoir. The volume of space between the bottom 152 of the reservoir 150 and the bottom 148 of the melting grate 140 is the lower fuel reservoir area 158.
The melting grate is suspended above at least the lower most portion of the bottom 152 of the reservoir 150. The bowl or basin may comprise other shapes other than curved, for example the bottom may be flat with obliquely angled side walls for intersecting with the melting grate.
The top 146 of the melting grate establishes a support surface for the wick system 170 and for solid fuel 201. Melting grate comprises a plurality of holes 142, 144 that allow melted fuel, such as melted wax to travel from the top surface of the melting grate down into the reservoir. The holes may be different sizes as that there are larger holes 144 and smaller holes 142. The wick system 170 comprises a wick, such as wick 110 or 130, the wick sheath 120, and optionally the wick support ring 160. The wick system 170 creates a burn chamber 172 within the hollow-core wick 130 and bounded by the wick sheath.
The hollow-core wick 130 has an upper surface 132 and a lower surface 138. The upper surface 132 of the wick may comprise a plurality of peaks 135 and valleys 131. The wick sheath has an upper surface 122, and a lower surface 128. The wick support ring 160 has an upper surface 162 and a lower surface 168. The lower surfaces 168, 138, 128 of each of the wick support ring 160, the wick 130, and the wick sheath 120 are supported on the upper surface of the melting grate 140. The wick system 170 may be placed on the melting grate in any particular location. In some embodiments, the wick system is centered on the melting grate. In some embodiments, the melting grate is 4.25 inches in diameter, but many other sizes are also possible. Each of the wick sheath 120, the wick 130, and the wick support ring 160 comprises a cylindrical shape, however, in some embodiments, each may comprise other shapes such as such a shown and described in
In some embodiments, the inside surface 126 of the wick sheath 120 is in contact with the outside surface of the wick 130 and the inside surface 136 of the wick 130 is in contact with the outside surface of the wick support ring 160. In some embodiments, the inside surface 126 of the wick sheath 120 is in close proximity but not in surface-to-surface contact with the outside surface of the wick 130 and the inside surface 136 of the wick is in close proximity with the outside surface of the wick support ring 160. The close proximity may comprise distances in the range of about 0.001 of an millimeters to about 5 millimeters. In the embodiment shown in
In some embodiments, a melting plate replaces the melting grate. The melting plate does not have any holes and the wick 130 is fed through lower holes (not shown) in the wick sheath.
In some embodiments, the reservoir is arranged to be positioned relatively close to the wick system to promote fast melt pool creation. The shape of the reservoir allows for a falling of melted wax toward the flame. The wax systematically melts from heat conduction, typically from the melting grate or a plate supporting the wick system. This is done by creating a shape that shifts the center of gravity of the melted wax toward the wick system as the wax melts.
Wick Sheath Apertures.
The wick sheath comprises a plurality of air intake apertures or holes 124. The holes 124 are spaced apart about the circumference of the wick sheath. The holes are located adjacent to the upper surface 122 of the wick sheath 120. In some embodiments, the holes are located in the top half or top quarter of the height of the wick sheath. In some embodiments, the holes are 0.06 inches in diameter and allow air into the burn chamber. The holes 124 allow air to be pulled through the porous wick and into the burn chamber. The air intake holes allow an increased amount of oxygen to be introduced into the burn system thereby resulting in a higher burning/operating temperature.
The number and size of air intake holes 124 in the wick sheath affects the burn performance of the wick system 170. For example, the flame can be reduced by utilizing fewer holes or no holes, thereby reducing or starving the combustion of oxygen. On the other end of the spectrum, if the number and/or size of the holes are too great, too much oxygen will be allowed and the flame will be too large for its intended use. The number of holes will affect the stoichiometry of the combustion, generally by using oxygen as the limiting reactant to make larger, soot free, stable flames. Finally, if the holes are too large and expose too much of the porous wick material, the exposed side of the wick at the hole could ignite. In some embodiments, it is preferred that the holes be less than ⅛ of an inch in diameter. In some embodiments, it is further preferred that the holes be less 1/16 inch in diameter. In one embodiment, the wick sheath comprises at between 2 and 10 apertures spaced apart equally about the circumferential outer side wall of the wick sheath.
In some embodiments, the wick sheath may comprise non-porous material such as metal, such as aluminum, copper, steel, iron, nickel, or a combination thereof. In some embodiments, the wick sheath may a comprise material that has a lesser heat conductivity than metal but will survive a flame, such as ceramic, stone, refractory materials, glass, or a combination thereof. The inner wick support ring may comprise the same types of material just described for the wick sheath. The wick support ring is optional and is provided to maintain the shape of upstanding the wick adjacent or against the wick sheath. Some wick materials do not require a wick support ring for maintaining the wick's shape. The reservoir 150 may comprise wood, glass, ceramic, metal, and high melting resin. In some embodiments, the wick is comprised of ceramic fiber paper, such as Fiberfrax® Ceramic Paper 970A manufactured by Unifrax LLC of Niagara Falls, N.Y. In some embodiments, the wick is comprised of one or more of ceramic fiber paper, sintered glass, porous metals, porous ceramics, porous rock, metal weave, fiberglass, and carbon composite.
Starter Wick.
In some embodiments, the burner system 100, 200 includes a starter wick 180 as shown in
Wickless Solid Fuel.
The burner system 100, 200 utilizes a solid fuel 190, 201. The solid fuel may be of a configuration as disclosed in U.S. patent application Ser. No. 13/640,478. U.S. patent application Ser. No. 13/640,478 is herein incorporated by reference in its entirety to the extent not inconsistent with the present disclosure. The solid fuel can be in either a pellet form or a pre-formed solid element such as shown in
The solid fuel used by the system may be comprised of solid wax fuels, such as soy wax, palm wax, beeswax, paraffin, or other hydrocarbon fuels that are solid below 90 Fahrenheit(F) and liquid above 220 F. More particularly, the solid fuel waxes used by the system may comprise those that melt when heated to temperatures in the ranges of 125 F to 180 F. The fuels usable with the burner system include not only solid fuels but also liquid fuels. Therefore, the fuel used can be any meltable solid or liquid hydrocarbon or glycol whose flash point is in excess of 180 F. Such fuels may include soy wax, palm wax, solid paraffin, liquid paraffin, olive oil, diethylene glycol, monoethylene glycol, among others.
In one embodiment, the solid fuel 190 has a priming section 192, a stoking section 194, and a main section 196 as shown in
Another embodiment of a wickless solid fuel 201 is shown in
In
Instead or in addition to the ignition portions of the wick, a starter wick, such as starter wick 180 may be used adjacent to the main wick to transfer the flame to the main wick. The starter wick, similar to the ignition portions of the wick, will have a lower total mass designed for quick ignition. The starter wick can act as a pilot light for the main wick, which may have a much larger heat capacity and therefore require a much longer time to ignite as compared to the starter wick.
The priming section is positioned so as to allow a typical igniting flame from a match or lighter to be in contact with the wick and to be close enough to melt at least a portion of the priming section. The priming section, once melted, preferentially flows toward and into the wick. The priming section, when melted, may fall directly on top of the wick, and/or it may fall on to the side wall of the wick, and/or it may fall adjacent, but not directly on the wick, but then flow toward and make contact with the wick. The priming section has generally the smallest mass as compared to sections 204 and 206 because it, along with the wick, needs to be elevated to ignition temperature quickly by the flame. A larger mass will take longer to melt and provide fuel to the wick. Therefore the priming section enables an accelerated flame start time at the wick. The priming section is sized to balance, during ignition, between not enough fuel to ignite the wick and not too much melted fuel so as to avoid flooding the wick.
The priming section may be initially melted by the ignition source, such as a match, lighter, or other flame source, before the flame begins on the wick. Once the flame begins on the wick and the ignition source is removed the flame on the wick will continue to melt the priming section. In some embodiments, the priming section, when melted by the ignition source, will flow directly to the portion of the wick that will first be ignited which is generally at or adjacent the placement of the ignition source.
In some embodiments, the priming section has a mass in the range of 0.01 grams to 0.5 grams and hangs over the top of the wick in such a manner that when the fuel melts, the resulting flow creates one or more drops of fuel that prime the wick. In some embodiments, the priming section has a mass of 0.5 grams or less.
The stoking section 204 is close enough to be melted primarily from heat radiation by the newly ignited flame at the wick and is generally of larger size than the priming section 202 because it needs to supply the fuel to wet the totality of the wick so that the full flame may develop. Unlike the priming mass, however, the stoking section needs to flow primarily away from the flame and toward the bottom portion of the wick otherwise the wick or flame may become flooded. Therefore the stoking section is positioned close enough to the flame to melt the fuel via radiating heat but far enough away to make sure the melting wax does not flow into the flame and flood the wick. A flooded wick would result in very slow flame development or may extinguish the flame. Flow channels, such as flow paths B and C of
The melted stoking mass flows away from the ignited section of the wick and down toward the base of the wick system, entering the wick system 170 from the bottom, and wetting the wick from the bottom. This feeding of the wick from the bottom stokes the flame as it develops more fully. In this manner, the newly ignited flame is not at risk of flooding and will not starve itself of fuel since the melted fuel is delivered quickly to the wick system 170.
The function of the stoking section is to fully develop the flame and increase the system operating temperature above that of the melt point of the solid fuel. The stoking section must be of sufficient mass to allow the flame to burn until the system reaches the desired melting temperature. If not, the system will be starved of liquid fuel and the ignited flame will go out leaving a solid mass of wax fuel behind. The stoking section must also be designed in such a way as to avoid flooding the wick at or near the ignition area. This is done by creating a physical design of the stoking section and its placement relative to the wick system that allows the melted fuel of the stoking section to flow to the wick either beneath the ignited portion of the wick or to the side of the ignited portion of the wick.
In some embodiments, the stoking section has a mass in the range of 0.25 grams to 2.5 grams. In some embodiments, the stoking section has a mass greater than 0.24 grams and less than 3 grams. In some embodiments, the stoking section has a mass that is 5 times the mass of the priming section. In some embodiments, the stoking section has a mass that is 25 times the mass of the priming section. In some embodiments, the stoking section has a mass that is in the range of 5 to 2500 times the size of the priming section.
The main section 206 is the largest of the three sections 202, 204, 206. The main section provides the bulk of the fuel that is melted primarily from conductive heat. Conductive heat is transferred from the flame through the wick sheath to the melting grate to the main section 206 in contact with the melting grate and within a radiating distance there from. Main section may also be heated through radiant heat transferred through ambient air from the flame at the wick. The main section provides a continuous supply of melted fuel to the base of the wick system to be drawn in and combusted in the burn chamber of the wick system 170 until the fuel in the lower fuel reservoir area 158 is exhausted. The main section is generally the furthest section from the flame and wick.
The main section has a mass that is sized depending on the desired total burn time of the system without a refill as well as the size of the melting grate 140 and/or the reservoir 150. In some embodiments, the main section has a mass in the range of 3 grams to 25 grams. In some embodiments, the main section has a mass in excess of 25 grams.
In some embodiments, the main section has a mass that is 10 times the mass of the stoking section. In some embodiments, the stoking section has a mass that is 12 times the mass of the stoking section. In some embodiments, the stoking section has a mass that is greater or equal to 10 times the size of the stoking section.
The solid fuel 210 may be configured, when placed adjacent other solid fuel as shown in
When the solid fuel 201 is positioned adjacent the reusable wick, the nature of the geometry of the solid fuel will manage the igniting, forming, and maintaining the desired flame. Upon placing a match, lighter, or other igniting element close to the point where the solid fuel touches or is adjacent the wick, the heat from the ignition source melts the relatively small amount of wax that then flows toward and into the wick from the top of the wick system. Because the total mass of the priming section fuel combined with the wick is small relative to the mass of the full wick filled with fuel, the ignition flame then can elevate the collective mass of the of the full wick and melted fuel to its ignition temperature and the system is primed.
Once the wick is ignited, the flame then melts through the remainder of the priming section and into the stoking section 204 of the wickless refill through radiating heat from the flame though the ambient air. However, rather than drawing the newly melted fuel directly into the flame, this section of melting fuel runs away from the flame and toward the bottom end of the wick, seeking to fully replenish the wick with melted fuel without restricting or flooding the developing flame at the top. The spacing of the stoking section from the wick system 170 should be such as to allow space for the newly melted wax to flow so that it does not flow down onto the flame. The wax melting from the stoking section generally, during at least a portion of the melting of the stoking section, travels down the exterior of the wick sheath that itself is beginning to be heated by the flame above. As the melted wax begins to fill or saturate the bottom of the wick, it enables the full development of the desired flame.
As the larger and more fully developed flame grows fed by fuel from the stoking section, the main section 206 begins to melt via conductive heating. The main section 206 is larger and comprises more mass than the stoking section or the priming section. The main section continues to supply/replenish the fuel within the wick from the bottom portion of the wick until the total mass of all fuel is exhausted and the flame is extinguished. When the flame runs out of fuel and is extinguished it will leave behind a dry wick ready to be used by another wickless wax refill.
Numerous geometries might be utilized to prime the wick by moving a relatively small amount of fuel to the point of ignition, to stoke the flame by moving more fuel away from the flame and toward the bottom of the wick, and to supply and replenish the reservoir 150. Exemplary embodiments of solid fuel 210, 220, 230, 240, 250, 260 geometries are shown in
As shown in
As the front contact surface 256 is located closer to the wick system 170, it will tend to melt first causing the solid fuel to sink further forward as shown in
The main protruding 284 has an upper protruding section 284j comprising a first forwardly extending portion 284a and a second forwardly extending portion 284b joining the first forwardly extending portion 284a at a curved nose section 284i. The upper protruding section 284j has opposite inwardly converging sidewalls 284g, 284h. Below the upper protruding section 284j is a mid section having a first facing surface 284c. Below the mid section, is a lower section 284k having a first front wall 284d, and a first lower wall 284m. The first lower wall 284m extends from the body 281. The first front wall 284d meets the first lower wall 284m at a curved intersection 284l. The lower section 284k has opposite side walls 284e, 284f. The main protruding section may be located at the midpoint between the side walls 289, 290.
The lower front wall 287 curves inward to create an open pool space 291 between the body adjacent and between the arms 282, 283. This pool space allows melting wax to gather between the body and the wick sheath to continue fueling the wick without flooding the wick. If open pool space 291 forming a gap 219 between the bottom 287a of the lower front wall 287 did not exist, the wax may flood the wick and extinguish the flame.
The solid fuel 280 is formed so when the arms contact the wick sheath the upper protruding section 284j is properly positioned above the wick. Therefore, melted wax from the priming section, which includes the portion of curved nose section 284i that extends over the wick, can fall on the wick and initiate ignition of the wick. Further the arms ensure there this is sufficient space within the pool space 291 for wax from the stoking section to flow down the solid fuel and to the base of the wick sheath to fuel the wick from the bottom. In some embodiments, the gap 219 between bottom 287a of the lower front wall 287 and the wick sheath is 0.125 inches at the bisecting vertical midline 293.
Each of the arms are mirror image identical about the bisecting vertical midline 293. Therefore only arm 283 will be described. The arm has a rising bottom section 283a, which meets the upper portion 238b at a curved end 283c. As shown in
In some embodiments, the lower section 284k and/or the mid section having a first facing surface 284c are configured to contact the wick sheath, as shown in
In some embodiments, the wick sheath is not welded or sealed to the melting grate along its entire circumference and as the wax becomes more easily flowing through higher temperatures, some wax will flow between the melting grate and the bottom of the wick sheath and into the bottom of the wick without falling through the melting grate and into the reservoir. As the wax begins to melt, it may be slow flowing wax that will not immediately fall through the holes in the melting grate. Therefore wax will pool on the surface of the melting grate in the gap 219 during initial burning.
Clog Resistance.
A system of method of resisting or preventing clogging of a reusable wick is disclosed.
Certain advantages are achieved when the liquid fuel level 314 is not in direct contact with the wick. When the fuel level 314 is not in direct contact with the wick 130, air 316 is drawn through the melting grate and into the bottom of the burn chamber 172 of the wick system 170. The gap 318 can be macroscopic in scale or microscopic, as long as it creates a situation where the bottom most portion of the wick material is no longer in direct contact with the fuel housed in the fuel reservoir 150 and there is a path for air to be drawn into the burn chamber from the lower opening of the wick system 170.
The gap 318 provides for an arrangement that resists or eliminates wick fouling or clogging for at least two reasons. First, throughout the operation of the system 200, since the bottom most portion of the wick is not in contact with the lowest portion of the fuel reservoir, any solids or particles that are suspended in the fuel will precipitate or fall to the bottom of the fuel reservoir and will not enter the wick material.
Second, when the fuel level sits above the melting grate, covering the bottom portion of the burner assembly and delivering fuel to the flame directly through the wick material as shown in
As a gap is created or maintained between the bottom of the wick and the top of the fuel level 316, air begins to be drawn into the burn chamber through the bottom of the burn chamber 172. The drawn air picks up the vaporized or gas phase fuel as it proceeds into the burn chamber and/or onto the wick and the vaporized or the vapor phase paraffin is combusted. Generally wax fuels vaporize at temperatures between 390 F and 420 F depending on the type of wax. With the addition of more air into the burn chamber, the resulting fire/flame 310 burns hotter, creates more thermal energy that vaporizes more fuel, then the flame of the system operating as shown in
Therefore the gap allows vaporized fuel to be drawn into the burn chamber premixed with oxygen with creates a hotter flame 310, as shown in
Once the cleaning cycle temperature threshold is met and/or exceeded, any solids that might have clogged the wick are retained in the bottom of the fuel reservoir and any accumulated varnish, tar, carbon deposits, or other elements are consumed, volatilized, or otherwise released from the wick material as the burn chamber begins to operate at the elevated cleaning temperature. The result is an assembly resistant to the clogging or fouling than is generally seen and expected as longer chain hydrocarbon fuels like waxes or paraffin are burned.
The system provides less soot or unwanted byproducts of combustion delivered to the air because the chemical ingredients prone to incomplete combustion are either retained in the unused portion of the fuel or combusted at a higher temperature.
The gap between the bottom of the wick system and the bottom of the fuel reservoir 150 creates a thermal buffer that allows the reservoir basin or bowl to be made of materials that are otherwise prone to thermal shock or degradation.
In one embodiment, the reservoir 150 is concave in shape with a nine inch diameter and two inch height. The reservoir 150 is comprised of transparent or translucent etched glass that allows the light of the flame 310 to shine through the fuel and down to offer down lighting to the area under the reservoir. The melting grate is a flat perforated aluminum sheet of 4.25 inch diameter. This creates a distance between the melting grate and the bottom of the reservoir 150 of about 0.5 inches at the center 151 of the reservoir 150. The wick sheath has a diameter of 1.5 inch and a height of 1.1 inch and is formed by cutting aluminum tubing cut at 1.1 inch increments. The wick has a height of 1.3 and comprises Fiberfrax® 550 F ceramic paper with a wavy pattern cut at the top to facilitate ignition. The solid fuel may be IGI 1239 granulated paraffin. In this embodiment, when the system reaches its end of use, the remaining fuel in the reservoir is about 0.2 inches deep at the center 151 and the entire surface of the wick, including the upper portion of the wick supporting the flame, is relatively clean of carbon deposits and is one that can easily be relit and used repeatedly.
In some embodiments, the gap between the bottom of the wick and the lower most point of the fuel reservoir 150 at the center 151 can be as small as the thickness of the melting grate. In such an arrangement the melting grate is spaced closely to the bottom of the reservoir 150. In some embodiments, the wick may comprise any kind of non-consumable material or refractory product. In some embodiments, the wick system diameter can range from 0.25 inches to in excess of 3 inches in diameter, the wick and support ring being signed correspondingly. In some embodiments, burn devices using this method can use one or a plurality of wick systems placed upon the grate to create a customized flame effect. The customized flame effect can comprise a flame pattern that spells out a message in words or letters. The customized flame effect can comprise a flame pattern emulates a flame fountain with some parts of the flame being taller than others. The flame fountain effect can be achieved by forming some wick systems that burner taller than other wick systems on the melting grate.
Wicks and Wick Sheaths.
Each of the top edge configurations shown on wicks 380, 390, 400, 410, 420, 430, can be used any of wicks 330, 340, 350, 360, and 370. Further, a wick may use more than one top edge configuration on the same wick. For example, a wick may comprise a portion of the top edge having the jagged top edge 406 configuration and another portion of the top edge having the wave top edge 416 configuration.
The wick system uses the wick sheath to provide the boundary of the burn chamber. Within that burn chamber is wick material that only partially fills the space within the wick sheath. The wick material extends above the wick sheath to facilitate ignition and to create the top flame beneath which the vapor phase fuel is housed or staged.
The inside of the burn chamber comprises at least 10% open space. In some embodiments, the inside of the burn chamber comprises more than 50% open space. The wick material can line the inside of the wick sheath or stand apart from the wick sheath but generally has at least one surface open to the burn chamber through which surface vapor phase fuel can be delivered to the burn chamber.
A lower portion of the wick exposed to liquid or vapor fuel delivers vapor phase fuel to the burn chamber while the uppermost portion of the wick maintains the fire near the top of the burn chamber. In this way, there is always an excess of fuel ready to burn.
The combustion stoichiometry is moderated and manipulated by the access to oxygen. In the wick system, this is done generally at least in one of at least two ways. One method is to perforate the side walls, such as with the holes 124, of the wick sheath to allow air to enter into the burn chamber through the wick or directly into the burn chamber. Another method to allow oxygen into the burn chamber is around the wick surface at the top of the burn chamber. This is accomplished by creating an uneven surface upon the top of the wick, such as those shown in
The advantages of this invention are many and some of which are provided below. The low ignition mass, both fuel and wick material, allow for both ease of ignition and faster flame development. The open geometry of the burning surface creates a larger flame without the expected increase in soot production. This larger flame, then, can be used to create much faster heat delivery to the system to melt additional solid fuel, to deliver a volatile ingredient to the air more quickly, and to create a higher operating temperature that can deliver a volatile ingredient more completely to the environment. This system works especially well if coupled with a thermally conductive base (a melting plate) or a heat conductive grate. By staging the fuel in its vapor phase (ready to burn) and limiting the access to oxygen, this invention balances the combustion stoichiometry to reduce soot production and even eliminate it at the smaller scales. The staging of the vapor phase fuel within the burner assembly creates a wind resistance when the covering flame is disrupted by the wind or a breeze. The systems of the invention having a wick and or wick sheath with a diameter of 2 inches or greater have withstood 30-40 mile per hour winds without the flame being extinguished.
In some embodiments, the wick is non-consumable and has a thickness of about 1/16 inch. The wick sits against the inner wall of the wick sheath and thereby creates the burn chamber within the exposed center, lined by the wick. The wick sheath is perforated aluminum with 0.0625 inch holes near the top of the wick sheath. The wick top is patterned to offer a natural ignition point. The height of the wick sheath is about 50-66% of the wick sheath diameter. The wick may be composed of FiberFrax® ceramic paper. In this embodiment, the burner system scales well from indoor candle to table-top burner to yard torch to fire pit.
The burning system can be refined or modified to accommodate a large variety of usage applications. The overall vertical height of the system can be extended verticality to showcase the flame or create a more vertical system, such as disclosed in FIG. 2 of U.S. patent application Ser. No. 13/640,482. A system with an extended vertical height may be suitable for outdoor applications where previously yard torches, such as TIM torches, have been used. In some embodiments, the wick materials used can be of several natures and types including but not limited to ceramic, fiberglass, porous rock, porous metal, or any other kind of refractory product like papers, felts, blankets, tissues, and mats. The thickness of the wick may be of any thickness suitable to the desired application. The burner chamber geometries can be widely varied including but not limited to cylindrical, box, oval, spiral, paired linear, bracketed, among others as shown in
From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred.
This application is a continuation of U.S. patent application Ser. No. 13/868,966, filed Apr. 23, 2013, which claimed the benefit of U.S. Patent Application No. 61/687,368, filed on Apr. 25, 2012, and U.S. Patent Application No. 61/687,248, filed on Apr. 23, 2012, and U.S. Patent Application No. 61/687,352, filed on Apr. 24, 2012, and U.S. Patent Application No. 61/688,750, filed on May 22, 2012, each application above is incorporated herein by reference in its entirety.