Patent Publication Number: US-7717104-B2

Title: Handheld device for fast electrical ignition of a charcoal grill

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to the use of an improved electrical hot-air gun for fast ignition of the charcoal-bed of a barbeque charcoal grill for home use. 
   2. Description of the Related Art 
   Hot-air guns, which produce a flow of hot air can effectively be used to perform various tasks including removal of paint, shrinking of tubes and wraps, soldering etc. They are available in models for the handy homeowner as well as semi- and full professional ones. What differentiates the simpler from the more expensive hot-air guns is the sturdiness and increased outlet temperature and volume of heated air in the more expensive versions. There are no handheld electrical ones available that are specifically designed to have a sufficient temperature outlet to effectively ignite a charcoal bed of an open BBQ grill. 
   One common way of igniting a charcoal grill is using lighter-fluid made out of a variety of petrochemical products. Among the many disadvantages associated with this method is that it is dangerous to handle petrochemical products close to an open fire. Another disadvantage is the large amount of hydrocarbons that the lighter fluid produces when burning. In Sweden alone the annual use of lighter-fluid is 2000 metric tons. Another disadvantage associated with this method is that the lighter-fluid occasionally gives the cooked food an off-flavor. 
   The problem with using a regular handheld hot-air gun to ignite fixed fuel such a charcoal on an open bed is that it has too low an outlet temperature given the loss of energy in an open bed such as in a open charcoal grill. This means that the ignition will at best take quite long time or will not work at all. Further, repeated such use of a regular hot-air gun will dramatically shorten its expected lifespan as it is not intended for long periods of use at the temperatures used during ignition. 
   There are, however, some other hot-air solutions than the present invention for igniting charcoal and other burnable materials on an open bed. One is described in U.S. Pat. No. 6,053,61 which is a specially-shaped dome to be fitted on a traditional hot-air gun to increase the effectiveness of the hot-air currents for accelerated ignition and burning of solid fuels, especially charcoal. Others such as the one described in WO9202765 A1 are driven by gas and require a propane tank or similar supply of fuel to operate and are therefore not as simple to use as the “LooftLighter” of the present invention, which requires only an electrical connection. Also, the lighter described in U.S. patent application Ser. No. 4,422,435 is gas driven. 
   Examples of previous electrical fire lighters for solid fuel such as charcoal include UK patent 959,765, UK patent 862,063 and UK patent 384,387. These lighters are all of larger construction making them less suitable for handheld ignition of a BBQ grill, but the largest difference compared to the present invention is their outlet temperature which is indicated in all three of these patents to be between 650-800° C. 
   Industrial hot-air blowers for various fixed installations, for example, in sealing bottles in a filling machine, such as LEISTER High Temperature Heater 10000 HT (from Leister Ltd, Sarnen, Switzerland) are available for outlet temperatures up to 900° C., however such heaters are not for handheld use. Regular multi-purpose hot-air guns normally give an outlet temperature of 300-600° C., such as model KX2000K by Black and Decker, (Towson, Md., U.S.A.). Some of the more professional handheld models typically have an outlet temperature going up to 600-650° C. (1100-1200° F.), for example Steinel HG3002LCD (Herzebrock-Clarholz, Germany). Due to its design with a high-effect heating element very close to the air-outlet, however, the handheld electrical igniter of the present invention is able to give a higher outlet temperature, making it significantly better in fast ignition of a charcoal-bed of an open BBQ grill. 
   It is therefore an object of the invention to provide a device comprising a handheld hot-air gun, which is constructed to deliver high outlet temperature, to be able to quickly ignite a charcoal bed or other solid fuel on an open grill or other surfaces. It is a further object of the invention to provide a design of such an igniter that will well withstand such high temperatures and also protect the user. 
   It is a further object of the invention to provide a scraper mounted on the igniter/heater front to be able to aid in cleaning the grating of an BBQ grill. 
   Other objects and advantages will be more fully apparent from the following disclosure and appended claims. 
   SUMMARY OF THE INVENTION 
   This invention relates to the use of an improved electrical hot-air gun for fast ignition of the charcoal-bed of a barbeque charcoal grill for home use. The invention also provides a scraper mounted on the igniter/heater front to be able to aid in cleaning the grating of an BBQ grill 
   Other objects and features of the inventions will be more fully apparent from the following disclosure and appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a top perspective exploded view of the complete assembly of the invention. 
       FIG. 2  is a cross-sectional view of the heating element position of the invention. 
       FIG. 3  is a perspective view of the grid scraper assembly of the invention mounted thereon. 
       FIG. 4  is a side view of the grid scraper attached to the front portion of the invention herein, which is shown as a cross-section. 
       FIG. 5  is a side view of the resistance wire with a portion of the wire shown with the ceramic coating. 
   

   DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS THEREOF 
   In the following detailed description of the preferred embodiments of the present invention, reference is made to the accompanying drawings which, in conjunction with this detailed description, illustrate and describe a specific preferred hot-air gun assembly. The invention may also be embodied in many different forms and should not be construed as limited to only the disclosed embodiments. The provided embodiments are included so the disclosure will be thorough, complete and will fully convey the scope of the invention to persons of ordinary skill in the art. 
   The hot-air gun of the present invention, named “LooftLighter”, has an improved position of the heating element in combination with high effect of the same, in order to increase the immediate temperature at the air outlet from the hot-air gun, compared to existing models. The location of the heating element at the very front position of the hot-air gun, close to the end used for ignition which is close to the air outlet, makes it possible to transfer maximum amount of energy into igniting the solid fuel. If a longer distance is used, such as in a regular hot-air gun, the energy losses becomes too large for efficient ignition and even if ignition is at all possible, it will take too long a time to be practical. The higher temperature of the output air is needed for a fast ignition of the charcoal bed of an grill. The “LooftLighter” is also specifically designed to withstand such increased temperatures and has also a scraping feature for cleaning of the grill grating. The hot-air gun of the invention ignites the charcoal BBQ in a much faster, safer and more convenient way than any other product on the market. In addition, the invention herein also saves the environment compared to petroleum based igniters. 
   The charcoal grill has a fast ignition and can be lit in less than 90 seconds with the invention. It is fast, fun and simple. The invention just needs to be plugged in and placed at the surface of the charcoal, and the button pressed. In 15 seconds, the coal starts to glow, and in 30 seconds the coal is burning. Depending on the size of the grill it takes about 90 seconds to have it fully ignited, and this performance is define herein as “fast ignition”. The output air directly in front of the “LooftLighter” should be between 700-1100° C., and preferably not lower than 850-950° C. 
   The preferred embodiment of the product of the invention also has another component: after re-using the grill there are many times parts of old food sticking to the grating which is hard to get rid of. By using the scraping assembly on the “LooftLighter” and with the combination of high heat and scraping, the old food is burnt away in a quick and hygienic way. 
   Another preferred feature of the invention is that it preferably has a ceramic heating element, which is resistance wire covered in ceramics for better heat characteristics. The ceramic heating element self-regulates the heat output in case the air inlet is blocked. In the preferred embodiment, cool touch covers, handle and perforated outer tubing outside the heating element provide additional safety. Thus, in the preferred embodiment of the invention, the heating elements themselves are fully encapsulated in ceramic and are unsurpassed in terms of even heating, durability and longevity. Another preferred feature of the invention is that it preferably has a stand to place the still warm hot-air gun on without possibly damaging the surface underneath, such a stand may be combined with a bottle-opener as illustrated in  FIG. 3 . 
   The invention herein also contains highly efficient DC brushless motors, such as a typical standard motor for such applications, which adds to the product high level of performance and reliability. Electronically monitored temperature and air flow as is known in the art are also preferred features of the invention herein. The hot-air gun is preferably turned on and off using a power-button connected to a power-switch or with a similar means. 
   Turning now to the drawings,  FIG. 1  shows a typical design of the hot-air gun  20  of the present invention may be comprised of a handle  22  formed by the covers  3 ,  4 ,  11  and  13 , although other configurations are within the scope of this invention. The outer shell portion comprising these covers of the hot-air gun  20  may be fabricated of a substantially non heat-conducting, and/or electrically insulated material such as plastic. An alternative one-piece design for the handle cover is shown in  FIG. 3 . 
   As in a typical hot-air gun, a motor  8  rotates a fan  6  to achieve air flow through the hot-air gun. Power may be supplied to the motor  8  by line voltage or the like as is known in the art. For instance, the handle of the hot-air gun may be configured to receive a conventional electric power supply cord  12 . 
   When power is supplied and the power-button  9  is pressed so that the power-switch  10  is activated to bring power to the motor  8  and the fan  6  so it rotates and to the heating element  1 , air is drawn into the hot-air gun  20  through air inlets  24  ( FIG. 1 , where one air inlet  24  is shown; a second air inlet would behind the motor/fan, but cannot be seen in this view). Any number of alternate placements of air inlets are contemplated by the present invention. The air drawn into the hot-air gun  20  through air inlets  24  passes through a heating assembly  7 . 
   The heating element in the assembly  7  is preferably made by a ceramic covered  38  ( FIG. 5 ) resistance wire  37  that is powered by the same energy source as the fan  6  and motor  8 . The resistance wire  37  as is known in the art is made of a single metal, such as an alloy with proper resistance to give the desired effect of the hot-air gun. The ceramic cover  38  as is also known in the art is essentially baked on to the resistance wire to increase life expectancy of the wire. In  FIG. 5 , only a portion of wire  37  is shown coated to illustrate the wire  37  itself; however, the cover  38  is on the whole wire and the wire does not show in the invention. The vertical lines in  FIG. 5  illustrate how the outer surface of the cover  38  might appear. 
   The heating assembly  7  warms the air as it passes over the heating element before it is expelled from the hot-air gun  20  through an outlet  26  in the end of the heating assembly  7 . The heating assembly  7  is covered by a perforated metal tube  2  to reduce the outside temperature of the heated parts of the hot-air gun  20  and to provide safety. 
     FIG. 2  illustrates a heating element  1  for use in a hot-air gun  20  in accordance with the present invention. In a preferred embodiment, the outside of the heating assembly  1  is protected and cooled by a perforated metal tube  2 . The distance, distance “x” in  FIG. 2 , between the front of the tube  2  and the ceramic covered heating wire  38  of the heating assembly  1  is 1 to 25 mm but preferably 8 mm or below. 
   In one embodiment, shown in  FIGS. 3-4 , the hot-air gun has a scraper assembly  27  attached for scraping off old burnt in food on the grating of a grill. Scraper assembly  27  comprises a housing  30 , having a round shape or what is needed to fit at the front of the hot-air gun (e.g., on heating assembly  7  in  FIG. 1 , so that scraper assembly  27  is inside outlet  26  when the device is assembled). It should be understood that various shapes and materials for both the scraper  28  and housing  30  may be employed and still be within the scope of the present invention. The first end  34  of the scraper housing  30 , which attaches to the hot-air gun  20 , is configured to be removably attached to the air outlet  26  of the hot-air gun  20 . The first end  34  of the scraper housing  30  may have a diameter that is slightly smaller than the diameter of the air outlet of the hot-air gun  20 , so that the first end  34  of the scraper housing  30  fits into the air outlet  26  of the barrel  36  of the hot-air gun  20 . In another embodiment, the first end  34  of the scraper housing  30  may have a diameter that is slightly larger than the diameter of the air outlet of the hot-air gun so that the first end of the scraper housing may be positioned around the hot air outlet end of the barrel of the hot-air gun. In either of these embodiments, the scraper housing  30  may be held in place on the end of the barrel  36  of the hot-air gun  20  by a variety of means including but not limited to frictional engagement with the end of the hot-air gun or by a fastening mechanism  32  being a combination of corresponding slots and projections or ridges and grooves on the hot-air gun barrel and/or the first end of the scraper assembly, as is known in the art. The length of the scraper  28  may be varied depending on its specific design. The stand  5  for the hot-air gun can in one embodiment be designed as is  FIG. 3 . 
   The foregoing disclosure is illustrative of the present invention and is not to be construed as limiting thereof. Although one or more embodiments of the invention have been described, persons of ordinary skill in the art will readily appreciate that numerous modifications could be made without departing from the scope and spirit of the disclosed invention. As such, it should be understood that all such modifications are intended to be included within the scope of this invention as described. The written description and drawings illustrate the present invention and are not to be construed as limited to the specific embodiments disclosed. Modifications to the disclosed embodiments, as well as other embodiments, are included within the scope of the invention.