Abstract:
An assembly for creating a fire display from a liquid fuel comprises a fuel receiving reservoir connected to a burner by a conduit, the conduit providing a flow channel for a liquid fuel from the reservoir to the burner. When a container of liquid fuel is placed in a bottle receiving tray the fuel is dispensed into the reservoir and in turn flows into the burner. Flammable vapors over the liquid fuel in the burner can then be ignited. The arrangement provides a continuous feed of fuel to the burner and allows safe replacement of the fuel container and replenishment of the fuel in the burner while the flame is present.

Description:
BACKGROUND 
     The invention relates to liquid fuel indoor and outdoor fire displays, particularly burner assemblies configured to burn a liquid fuel, such as an alcohol, paraffinic oils, plant oils, and flammable petroleum products, either in a liquid or gel form. 
     Historically, alcohol burning hearth products (fireplaces, stoves, log sets, vessels for containing open flames, etc) comprise a burner that is filled with alcohol, usually a denatured ethanol, or in the alternative, cans of flammable gelled alcohol, that are then lit to create the flame. Depending on the configuration of the burner and the size of the fuel reservoir, once ignited the fuel will burn until consumed, generally for 1-4 hours. Some burner configurations include a damper that will allow the flame to be extinguished prior to full consumption by covering the flame and restricting access to air. To extend the burning time the user typically has to wait until the fuel has burned completely, or the flame is extinguished, and the burner has cooled down before adding more flammable liquid or replacement can of gelled fuel into the burner and lighting it again. This procedure presents a number of problems which include:
         a) The possibility of spilling a highly volatile and flammable fluid on the fireplace or stove assembly and log set, which presents the possibility of unintended combustion thus creating an unsafe situation;   b) Spilling the fuel on a person&#39;s arm, clothing or on the floor which can also create a fire hazard;   c) Because the fuels are highly volatile, and it is the vapors off the fuel and not the liquid fuel itself that is burning, these vapors present a very serious risk of accidental ignition. This hazard requires the user to wait for the flame to extinguish and the burner to cool down before refueling to prevent vaporized fuel from spontaneously igniting during the filling process;   d) Additionally, ethanol, unless specifically blended with additives to provide a visible flame, tends to burn with a nearly invisible color, especially in well-lit areas, causing spills to be very dangerous since it is sometimes impossible to notice that the fuel has ignited. Certain burner assemblies are designed to create yellower flames that are more visible, especially after the fuel has been ignited for some time; the conditions that make the flame visible in the burner assembly do not exist to allow visualization of burning fuel spills;   e) The fuel level inside the burner of an ethanol burning assembly is constantly changing as the fuel is consumed and thus is not always at an optimum level for aesthetics or for clean combustion of the fuel.       

     These liquid fuel burners in many instances are used as unvented appliances in unvented spaces. As a result, the emissions from combustion end up in the room. Thus clean and complete combustion is very important. An improperly designed or operated liquid fuel burner, or the use of the wrong liquid fuel, can release fuel vapors and carbon monoxide into the room. As a result, consumers have been reluctant to use the currently available ethanol burners. 
     One product provides for pouring fuel into a reservoir that is then slid into the fireplace assembly from outside the burner assembly. However, this design still requires pouring the fuel from an open bottle, allows for the release of flammable vapors and does not safely allow additional fuel to be added while the fuel is burning. 
     SUMMARY 
     A particular advantage of the disclosed design is that it allows the user to replenish the fuel while the flame is burning without any hazard of fuel spill or vapor release. The device disclosed herein provides a fuel tray and fuel feed arrangement designed to keep the burning vapors above the fuel surface within a preferred range within in the burner for proper and complete combustion for a substantial portion of the time that a flame is being provided. Additionally, in one embodiment the burner has a sloping bottom (to the right and/or left of the unit) which allows the fuel to accumulate to the right and/or left of the center of the burner so that when the fuel in the burner is nearly consumed the user can see that the flame is no longer burning across the entire burner surface, thus providing a visible signal that the unit needs to be refilled. Alternatively, if more than one burner is used, one or more burners may be positioned lower than the other burners so that fuel in that burner continues to burn while other burners run out of fuel. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a front perspective schematic view of a first embodiment of a liquid fuel burner assembly incorporating features of the invention. 
         FIG. 2  is a front perspective schematic view of the liquid fuel burner assembly of  FIG. 1  including a fuel delivery bottle. 
         FIG. 3  is a front perspective schematic view of the burner and fuel reservoir portions of  FIG. 1 . 
         FIG. 4  is a top schematic view of the liquid fuel burner assembly of  FIG. 1  with artificial logs placed on top of the burner and fuel reservoir assembly. 
         FIG. 5  is a left end schematic sectional view taken along line  5 - 5  of  FIG. 4  showing the liquid fuel burner assembly of  FIG. 1  in operation. 
         FIG. 6  is a left end schematic sectional view taken along line  6 - 6  of  FIG. 1  showing the liquid fuel burner and fuel reservoir assembly of  FIG. 1  prior to installation of a fuel bottle. 
         FIG. 7  is a left end schematic sectional view taken along line  6 - 6  of  FIG. 1  showing the liquid fuel burner and fuel reservoir assembly of  FIG. 1  after installation of a fuel bottle but prior to ignition. 
         FIG. 8  is a left end schematic sectional view taken along line  6 - 6  of  FIG. 1  showing the liquid fuel and fuel reservoir assembly of  FIG. 1  after burning for a period of time. 
         FIG. 9  is a left end schematic sectional view taken along line  6 - 6  of  FIG. 1  showing the liquid fuel burner and fuel reservoir assembly of  FIG. 1  after burning for an additional period of time. 
         FIG. 10  is a front schematic perspective view of the burner without the burner top. 
         FIGS. 11 and 12  are schematic drawing of second and third embodiments of the liquid fuel burner assembly including multiple burners. 
         FIG. 13  is a top schematic view of a bottle containing a liquid fuel for placement in the burner assemblies of  FIGS. 1-12 . 
         FIG. 14  is a front schematic view of a bottle containing a liquid fuel for placement in the burner assemblies of  FIGS. 1-12 . 
         FIG. 15  is end schematic view of a bottle containing a liquid fuel for placement in the burner assemblies of  FIGS. 1-12 . 
     
    
    
     DETAILED DESCRIPTION 
     Disclosed herein are arrangements for feeding liquid fuel in indoor and outdoor fire displays. The arrangements are particularly suited to the delivery of alcohol based liquid fuels, particularly methanol, ethanol, butanol, etc. but are not so limited. Other liquid fuels can be used such as ester oils, plant oils, paraffinic compositions, and flammable petroleum products, either in a liquid or gel form. The fire displays may be in a fireplace or stove or free standing such as a fire pit or decorative flame display with or without artificial firelogs. As alternatives, the fire displays may include, in place of the artificial logs various media to enhance the decorative appearance of the fire display, such as glass beads, chunks or shards, stones, metal sculptures, water features, etc and various combinations thereof. The disclosure herein is directed to an arrangement for continuously feeding the liquid fuel and is not dependent on the decorative materials surrounding the burner and the burning vapors emanating from the fuel. 
     Referring to  FIGS. 1-4  and as best shown in  FIG. 3 , a liquid fuel burner assembly  10  includes a fuel receiving reservoir  12 , a burner  14  connected to the fuel receiving reservoir  12  by a conduit, preferably a tube  16  or trough, and a bottle receiving tray  20 . While a structure referred to as a “tray” is shown, the tray merely identifies a location for placement of the bottle and a physical structure such as a tray is not necessary. A bottle  22  containing the liquid fuel  24 , such as shown in  FIGS. 13-15 , is designed to be placed on the bottle receiving tray  20  with an access port or pouring spout  26  in the bottle  22  downwardly positioned over the fuel receiving reservoir  12 . The term “bottle” is used to indicate any container for the liquid fuel and it is not intended to limit the disclosure to a glass or plastic container. The assembly may include a piercing implement  28  as shown in  FIGS. 2 ,  5 ,  7 ,  8  and  9  or other suitable bottle openers so that when a sealed bottle  22  is placed on the tray  20  the pouring spout  26  is opened allowing the liquid fuel to pour out of the bottle  22  and into the fuel receiving reservoir  12 . Alternatives include but are not limited to valves, removable plates, or other devices intended to prevent premature delivery of the fluid from the bottle. 
       FIG. 4  is a top view of the liquid fuel burner assembly  10  of  FIGS. 1-3  with artificial logs  38 ,  39 , preferably constructed of a ceramic material or other non-flammable material, formed to resemble real wooden logs. As best shown in  FIG. 4 , the burner  14 , which may comprise one or more compartments, is positioned to provide a burning area between the rear log  38  and the front log  39 . When the vapor  32  over the liquid fuel  24  is ignited to produce a flame, as described below, the appearance of the assembly appears to an observer as a natural log fire. 
       FIG. 5  is a cross sectional view taken along line  5 - 5  of  FIG. 4 , providing a schematic representation of the liquid fuel burner assembly  10  in operation. A flame  48  is shown emanating from vapors above the fuel  24  residing in the burner  14  at a location between the front and rear artificial logs  38 ,  39 . One skilled in the art will recognize that while the disclosed embodiment shows two artificial logs, it is contemplated that more than two logs and/or more than two burners  30  can be used to provide a larger appearing fire. 
       FIG. 6  shows one particular embodiment of a liquid fuel burner assembly  10  prior to placement of the bottle  22 . On placing the filled fuel bottle  22  on the bottle receiving tray  20  the sealed bottle access port  26  is pierced by the piercing element  28 . Fuel  24  then flows from the bottle  22  into the fuel receiving reservoir  14  and then through tube  16  and into a burner  14 . Flow into the reservoir  12  stops as a result of the creation of a lesser pressure space (a vacuum) that forms in the bottle  22  in the air space over the fuel as the fuel flows out of the bottle and the fuel level in the reservoir  12  is above the lip of the pouring spout/access port  26 . This arrangement allows the burner  14  to fill only to a preset level slightly above the bottom edge of the access port  26 , which in turn provides a fuel level in the burner  14  approximating the height of the fuel  24  in the fuel receiving reservoir  12  as shown in  FIG. 7 . 
     Flammable vapor  32  accumulates above the surface of the liquid fuel in the burner  14 ; once ignited the flame then emanates from the vapor  32  at a distance above the fuel surface  34  as shown in  FIG. 5 . The vapor can be lit using any flame source, such as a match, propane or butane lighter, spark igniter, heated surface such as an electrically heated coil, etc.  FIG. 4  shows an optional access port  50  for insertion of the ignition means into the vaporized fuel. In the alternative, the access port  50  may instead be a built-in igniter such as a spark generator or an electrically heatable coil. As the fuel  24  in the burner is consumed by burning of the vapors, the fuel level in the burner  14  begins to drop. This in turn causes the fuel level in the fuel receiving reservoir  12  to likewise drop slightly, such as shown in  FIG. 8 , allowing air  36  (as represented by the arrows in  FIG. 8 ) to flow into the bottle  22 , thus allowing more fuel  24  to flow from the bottle to replenish the fuel levels in the reservoir  12  and burner  14  until the fuel in the reservoir  12  once more covers the bottle opening ( FIG. 9 ), thus stopping fuel flow. The fuel levels shown in the drawings are exaggerated for clarity; in actual operation the fuel level stays in a narrow range just below to just above the lip of the access port opening. This cycle continues until the bottle  22  is empty, at which point another bottle  22  can be placed into the bottle receiving tray  20 , thus refilling the burner  14 . Changing bottles does not require waiting until the flame is extinguished. Prior art devices usually required complete consumption of the fuel in the burner, and the liquid fuel burner assembly  10  to have cooled down. As taught herein, a bottle of fuel typically containing 0.5 to 2 liters of fuel can be installed in the burner assembly to support a burn for at least about 1-4 hours. However, larger containers can be used and the assembly described herein is not limited by the size of the containers. A new bottle can be installed once the previously installed bottle is empty, so that the flame can burn continuously. The fire time is not limited in time to a burn from a single bottle of fuel; it is limited only by the quantity of fuel bottles available. This design also allows the burner to be much smaller than most prior burners as the size of the burner does not depend on the size of the fuel reservoir necessary to hold enough fuel for a sustained burn. Having a smaller burner results in a smaller mass, thus allowing the burner to heat up faster so that the flame reaches its full effect much faster than prior designs. 
     The embodiment of  FIGS. 1-9  includes a large burner  14  which is divided into two compartments. However, single compartment burners are also suitable.  FIGS. 11 and 12  are schematic drawings of a second and third embodiment including multiple smaller burners  14  connected to a fuel receiving reservoir  12 . In  FIG. 11  three burners  14  are spaced from the fuel reservoir  12 , each burner receiving the liquid fuel through a dedicated tube  16 . The arrangement in  FIG. 12  has a single tube  16  attached to the reservoir  14  that tube then being connected to the auxiliary tubes  17  for feeding the individual burners. However, the invention set forth herein is not limited to the embodiments shown and one skilled in the art, based on the teachings herein will recognize that numerous variations with multiple burners, feed tubes and fuel reservoirs can be utilized to move the flammable liquid from the storage bottle to the burner and all of these embodiments will allow the use of multiple bottles of liquid fuel, all of which can be readily replaced without interrupting the flame in the one or more burners. While not shown, it is contemplated that multiple fuel bottles and multiple fuel reservoirs can likewise be used to fuel one or more burners. Further, the multiple burners can be positioned so that one or more burners will contain fuel after the fuel in the other burners is depleted, to provide the visible indication that it is time to replenish the fuel supply. 
     The embodiment shown in the Figures allows for placement of the fuel bottle and fuel receiving reservoir in the liquid fuel burner assembly  10  but at a location where it is also protected from the heat of the flame. To further protect the fuel bottle  22  and liquid fuel burner assembly  10  from the open flame in the embodiment of  FIGS. 1-9 , they are covered by a hollow artificial log  38  made from ceramic fiber with an openable cover such as shown in  FIGS. 4 and 5 . The embodiment shown has an opening in the top of the log that is covered by a hinged door  40 . A log  42  with a similar outward appearance also sits adjacent and behind the burner top  18 . When the door  40  is closed the log  38  looks like a conventional log in front of the fire. When a fuel bottle  22  needs to be placed in the burner assembly  10  the door  40  is opened by swinging upward or rearward so that it also creates a protective barrier from the flames. The used, substantially empty bottle  22  is removed and the new bottle  22  is inserted in its place and pushed down so that the piercing implement  28  punctures the sealed access port  26 , thus allowing fuel to flow into and replenish the reservoirs  12 ,  14 . 
       FIG. 10  illustrates a further optional feature of the liquid fuel burner assembly  10  wherein the burner  14  has a sloped bottom  42  such that when the fuel is almost totally consumed the remaining fuel resides in the lowest end  44  of the tray, said lowest end constituting a fuel well. As a result the flame, which emanates from the vapor over the remaining fuel in the well, is concentrated at the lowest end  44  of the tray  42 , there being no fuel at the opposite, higher end  46 . An observer of the flame is then alerted by the flame burning at only one end of the burner  14  above the fuel well that almost all of the fuel  24  has been consumed and it is time to replace the empty fuel bottle  22  with a full bottle, thus replenishing the fuel supply in the burner  14 . 
     While one embodiments disclosed herein describes a device and method for providing a continuously burning flame in a fireplace enclosure, including artificial logs, one skilled in the art will recognize that the assembly of various components and their method of use is not restricted to placement within an enclosure and can be readily adapted to use in fire pits and decorative flame display arrangements both indoors and outdoors. For example,  FIGS. 11 and 12  illustrate alternative embodiments including multiple burners. Based on the teachings herein multiple alternative arrangements can be assembled to receive one or more bottles of liquid fuel in one or more locations, and then distribute that liquid fuel to one or more burners in a manner that provides for replacing the fuel source while the flame is burning without a need to first extinguish the flame or causing a fire hazard from fuel vapors during the refilling procedure.