Abstract:
A self-extinguishing candle having at least one layer of dry fire-suppressant material is disposed adjacent to the candle wick. The fire-suppressant material extinguishes a flame burning down the wick on contact. Providing the candle with layers of the fire-suppressant material between layers of the candle body allows the candle to self-extinguish then be relighted after removal of excess fire-suppressant material.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to self-extinguishing candles and methods for their manufacture. 
       BACKGROUND OF THE INVENTION 
       [0002]    Recent trends in home decor have seen an upswing in candle sales. In the U.S. alone, annual sales of candles for decorative, lighting and religious purposes topped 2 billion dollars in 2007. At the same time, however, residential fires stemming from candle use have increased drastically, with more than twice as many incidents being reported in 2005 than in 1990. According to the National Fire Protection Association, falling asleep was a factor in 12% of home candle fires and 26% of the associated deaths in 2005. Overall, candle-related fires now account for about 4% of all residential fires in the U.S. 
         [0003]    Despite the pressing need for enhanced candle safety, the art has yet to develop simple, cost-effective means to provide candles with means to self-extinguish after periods of use or inattention. Many approaches to the problem include structures adjacent to the candle wick that deprive the flame of oxygen when the candle has burned to a predetermined level. For example, U.S. Pat. No. 7,293,984 employs a series of wicks separated by a “bare core.” When each wick burns down to the bare core portion of the candle, the flame no longer has material to burn and goes out. The next wick in line can then be lighted. 
         [0004]    U.S. Pat. No. 7,040,888 utilizes a single wick surrounded at points along its length by tubular members. When the wick burns down to the level of each tubular member, it purportedly becomes deprived of fuel and the flame is extinguished. Removing the tubular member exposes the wick for relighting. 
         [0005]    U.S. Pat. No. 4,496,307 also utilizes a tubular member, but as a repository for a combustible fuel. The candle wick extends through the tubular member, which can be adjusted to increase or decrease the wick&#39;s access to fuel. Denying the wick access to fuel causes the flame to go out. 
         [0006]    Another commercial design snuffs the candle wick at its base by providing a sleeve therearound of polyethersulfone and polyvinylchloride. When heated, the polymer sleeve (disposed within a tubular member) expands and exerts pressure on the wick, cutting off capillary flow until the flame extinguishes. 
         [0007]    Despite such innovations, the risk of fires from candle use has remained high, making flameless candles (electric or battery-powered products) increasingly popular. However, no such product exactly duplicates the appearance, warmth and appeal of conventional wick candles. 
         [0008]    In contrast to the prior art, the invention provides a simple, user-modifiable self-extinguishing candle and method for its manufacture. 
       SUMMARY OF THE INVENTION 
       [0009]    A candle consisting of a meltable solid wax body and a wick disposed therethrough is provided with at least one layer of a dry fire suppressant material adjacent to the wick. When the wick burns down to the layer of dry fire suppressant material, contact therewith causes the flame to be extinguished. 
         [0010]    In one embodiment of the invention, the fire-suppressant material is a known chemical fire-suppressant powder of silica, alumina or titania. 
         [0011]    In a preferred embodiment of the invention, the fire-suppressant material is a bicarbonate composition of sodium, calcium, potassium, aluminum or halide (e.g., borate). An especially convenient fire-suppressant material is baking soda. 
         [0012]    The self-extinguishing candle of the invention may be manufactured by forming the candle body in layers with a bore for insertion of a wick therethrough, or by forming the candle over a layer of the fire-suppressant material in a container, such as a jar. The dry fire suppressant material is applied around the bore or, where the wick is placed into a candle form before formation of the candle body (e.g., with melted wax), around the wick. In this embodiment, the fire-suppressant material is preferably applied as a ring all around the wick, and may extend diametrically outward toward the candle body&#39;s outer edge. 
         [0013]    Being heat-resistant, the fire-suppressant material will not dissolve or melt in contact with melted candle wax, and so the wax may be applied directly over the fire-suppressant material. If multiple layers of fire-suppressant material are desired (so the candle may be extinguished and relighted repeatedly), the manufacturing process may be repeated until the candle is of the desired size and shape. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a cutaway view of a candle having a layer of fire-suppressant material disposed between layers of wax. 
           [0015]      FIG. 2  is a cutaway view of a container candle having a layer of fire-suppressant material disposed at the bottom of the container beneath the candle body. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    Turning to  FIG. 1 , an exemplary candle of the invention is illustrated. The candle has a body  1  formed of a meltable solid, such as a paraffin wax or wax/polymer mixture. Body  1  is defined by a cylindrical wall  2  and vertical layers  3  and  3 ′ of solid candle wax. A conventional wick  4  is disposed vertically therethrough. Sandwiched in between layers  3  and  3 ′ is a layer of a dry fire-suppressant material  5 . Dry fire-suppressant material is disposed on wax layer  3 ′ to form a ring  5  around wick  4 . 
         [0017]    In this embodiment of the invention, the fire-suppressant material ring  5  extends around wick  4  and outwardly to cover wax layer  3 ′, ending at the outer diameter of the ring in contact with the inner surface of cylindrical wall  2 . It will be apparent to those in the art, however, that the circumference of ring  5  need not extend all the way outwardly to cylindrical wall  2 , but may be of lesser diameter, rendering cylindrical wall  2  thicker; e.g., for molding of a decorative design onto the outer surface of body  1 , or for co-molding of ornamental items, such as leaves, thereinto. 
         [0018]    For use in pillar and taper candles, a relatively thinner wall  2  will allow the user to slice through the candle at the joinder of the ring of fire-suppressant material and the wax layer beneath (e.g., between ring  5  and layer  3 ′), to allow the candle to be relighted after the flame is extinguished on contact with the fire-suppressant material. If desired, the user may shake or rinse off any fire-suppressant material remaining on the surface of the wax layer beneath. 
         [0019]    For jar or votive candles with multiple layers, the fire-suppressant material can be scooped or shaken out to expose a layer of wax beneath for reuse of the candle. Alternatively, as shown in  FIG. 2 , a jar, votive or other container candle can simply have a layer of fire-suppressant material  6  disposed on the bottom of container  7  beneath candle body  1  (and in contact with wick  4 ), which will extinguish the flame once the wick has burned down to its base. 
         [0020]    Ring  5  need only have a circumference of sufficient diameter to ensure that sufficient material is in contact with the wick to extinguish a flame burning therethrough on contact. At a minimum, it is preferable for the ring to have a diameter equivalent to the thickness of the wick. The diameter of the ring will therefore be larger for larger wicks, and for wicks with enhanced burn characteristics, such as metal core wicks, or smaller for thinner wicks, such as a 15-18 ply flat braid wick. 
         [0021]    The thickness of ring  5  is shown in  FIG. 1  as being substantially equal to the thickness of wax layers  3  and  3 ′; however, it may (and in multiple layered candles, preferably will) be thinner than layers  3  and  3 ′. At a minimum, the ring of fire-suppressant material will be thick enough to prevent the wax layer above from seeping substantially through to the wax layer below while the former is added to the candle form in melted form. To that end, the ring will be applied over the wax layer above so that none of the latter is visible therethrough. 
         [0022]    Chemical dry fire-suppressant materials are known in the art, and are suitable for use in the invention, including powders of silica or metals (e.g., alumina or titania). Surprisingly, more commonly available materials may also be used as fire-suppressant materials in candles of the invention, in particular sodium, aluminum, calcium, potassium or halide bicarbonate compositions. Conveniently, ring  5  may be formed of aluminum bicarbonate, known commonly as baking soda, such as ARM &amp; HAMMER® Baking Soda. 
         [0023]    Layers  3  and  3 ′ as well as ring  5  may be alternately provided into a candle form in a fashion similar to the method used to craft candles of layered colors. The base layer of the candle (formed on the bottom of the candle form) is of a wax or wax composite (e.g., paraffin/polymer), preferably of at least the thickness of wall  2 . A layer of fire-suppressant material provided over a base having the thickness of wall  2  will allow the candle to extinguish before reaching the metal tab typically provided at the base of a wick (not shown). Being heat-resistant, the fire-suppressant material will not dissolve or melt in contact with melted candle wax, and so the melted wax may be applied directly over the fire-suppressant material and allowed to cool thereon. 
         [0024]    If multiple layers of fire-suppressant material are desired (so the candle may be extinguished and relighted repeatedly), the manufacturing process may be repeated until the candle is of the desired size and shape. The layers of fire-suppressant material can be spaced apart so the candle burns for a pre-determined period of time before the flame is extinguished. The topmost layer of the candle will be formed of wax. 
         [0025]    The invention having been fully described, its practice is illustrated by the examples below, in which standard abbreviations for measurement values are used. The examples shall not be read to limit the scope of the invention, which is defined by the appended claims. 
       EXAMPLE 1 
     Method of Manufacturing a Self-Extinguishing Candle 
       [0026]    A 4 inch long 18 ply flat braided wick with a distal metal tab was centered in a 2.5 h×2.5 w tin candle form. A 0.25 inch layer of ARM &amp; HAMMER® Baking Soda was applied around the wick to cover the bottom of the candle form. Commercially available candle wax (paraffin) was melted and poured into a to a thickness of 2 inches. The wick was trimmed to a length of 0.25 inches above the top layer of cooled wax. 
       EXAMPLE 2 
     Flame Extinguishment in Candles with Single and Multiple Rings of Fire-Suppressant Material 
       [0027]    The wick of the candle described in Example 1 was lit and allowed to burn normally. In approximately 11 minutes, the wick had burned through the wax. On contact with the baking soda, the flame went out, and remained extinguished.