Stoves and furnaces – Stoves – Cooking
Reexamination Certificate
1999-09-27
2001-05-01
Price, Carl D. (Department: 3743)
Stoves and furnaces
Stoves
Cooking
C126S007000, C126S010000, C126S011000, C110S108000, C110S110000, C110S293000, C110S294000
Reexamination Certificate
active
06223737
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to pellet fuel heating units or burners, and more particularly to a grill that utilizes a solid pellet type fuel, and particularly corn kernels.
The use of solid pellets as a fuel source is known, particularly in the art of stoves and the like. For example, U.S. Pat. No. 5,351,633 describes a heating unit particularly suited for burning corn kernels. The corn kernels provide an inexpensive, clean, and readily available fuel source. Other types of solid pellet heating units are also available, for example wood pellet heating units are also known.
A substantial problem with conventional fuel heating units has been the ability to consistently sustain the combustion reaction. One typical problem is with the method of providing air to the fuel to sustain the combustion. Typical stoves or heating units are closed and vented systems and utilize either a positive or negative pressure system for supplying combustion air to the heating unit. The conventional systems utilize a blower to supply air to the burner portion of the heating unit. If the blower is located upstream of the heating unit, than the unit is said to be a positive pressure system since the fire box will have a pressure greater than atmospheric. If the blower is located beyond or downstream of the fuel burner, the system is a negative pressure system and combustion air is essentially sucked into the burner, which has a pressure slightly less than atmospheric.
However, the use of either positive or negative pressure systems present several problems. For example, with the positive pressure system, the fire box is under pressure so that when the door or other access to the fire box is opened, smoke and other matter is generally pushed into the room. With the negative pressure system, there is a tendency for the blower to clog from the particulate material and the exhaust gases. Neither of these systems would be particularly suitable for outdoor grill applications.
The use of charcoal, gas, and wood as a fuel source for outdoor barbeque grills is well known. The styles and configurations of outdoor grills are vast and varied in the industry. However, conventional grills have inherent disadvantages depending particularly on the type of fuel utilized by the grill. For example, creosote chemicals, hydrocarbons, gases, and other undesirable chemicals actually cook into the food, particularly if charcoal or wood is the fuel source.
Propane or natural gas grills pose the additional disadvantages of potential dangerous leaks, and explosion hazzards.
Accordingly, the industry is continuously seeking to improve the safety, economy, and overall reliability and effectiveness of outdoor grills.
The present invention seeks to provide an improved solid pellet heating unit that is particularly suited for, but not limited to, an outdoor grill while overcoming the problems encountered with conventional solid pellet fuel burning units.
OBJECTS AND SUMMARY OF THE INVENTION
A principal object of the present invention is to provide an improved pellet fuel burning device.
It is also a principal object of the present invention to provide an outdoor grill that utilizes a solid pellet fuel.
It is an additional object of the present invention to provide a corn kernel fuel grill that cooks food efficiently, safely, and without chemicals of any sort being introduced into the food.
Still a further object of the present invention is to provide a safe and reliable outdoor grill fueled by inexpensive and readily available corn kernels.
Additional objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In accordance with the objects and purposes of the invention, a pellet fuel burner or heating unit is provided. The inventive burner or heating unit will be described herein as an outdoor barbeque grill. However, it should be appreciated that the grill embodiment of the invention is being described for explanation purposes only and is in now meant to convey that the invention is limited to grills. The heating or burner unit in accordance with the invention may have a wide array of uses and embodiments, for example a portable heating unit, stove, etc. All such embodiments and uses are within the scope and spirit of the invention.
The grill embodiment according to the present invention is not limited by any particular housing or design configuration. For example, a vast array of designs and styles of grills are known in the industry and the present invention is applicable to all such grills.
The present grill includes a fire box having a generally open top plane. A cooking surface is defined across the top plane. The cooking surface may include an upper grill surface with a grate disposed therebelow. Heat distributing substances, such as ceramic briquettes, and the like, may also be utilized. For example, such ceramic devices may be placed on top of a grate below the grill surface. Heat distributing baffle plates may also be utilized, for example below the grate surface, to evenly distribute and deflect heat from the burner unit across the cooking surface.
The grill includes a pellet burner unit disposed within the fire box below the cooking surface. The burner unit may comprise a perforated pellet holding device and is generally surrounded by a combustion air chamber. The holding device and combustion air chamber may be formed by a box-like structure having outer walls and perforated inner walls. The combustion air chamber is defined between the outer and inner walls. The inner walls define the pellet holding space or device.
A pellet feeding device is provided with an opening into the fire box and is disposed so as to feed the solid pellets, for example corn kernels, into the burner unit. In a preferred embodiment, the pellet feeding device comprises an auger mechanism fed by a pellet storage device, such as a corn hopper. The auger is housed in an auger channel having an inlet in communication with the pellet storage device or hopper, and an outlet that is disposed in the fire box above the pellet burner unit. In this manner, the auger moves the pellets through the auger channel and causes the pellets to drop out of the auger channel outlet and into the pellet burner unit. A power supply and drive mechanism, such as a powered motor, is provided for driving the auger mechanism.
A pressure box is provided having an inlet supplied with combustion air at a positive pressure. In a preferred embodiment, the pressure box is supplied with the combustion air by way of a powered blower. The pressure box has a first outlet into the fire box that is disposed above the burner unit and is configured to direct combustion air down into the burning unit. A flow directing member, such as a flow channel, nozzle, or the like, may be utilized in this regard.
The pressure box further includes a second outlet into the fire box that is disposed generally below the pellet retaining device of the burner unit and is configured to direct combustion air up into the burner unit. By utilizing a combination of a first outlet disposed above the burner unit and a second outlet disposed below the burner unit, a turbulent combustion air flow is generated through the burner unit to sustain combustion of pellets, and particularly corn kernels, within the burner unit. For example, in the embodiment wherein the burner unit comprises a box-like structure having a combustion air chamber defined between outer walls and perforated inner walls, the second outlet of the pressure box lets out into the combustion air chamber such that the combustion air circulates within the combustion air chamber around and into the perforated holding device. The pellets or corn kernels are dropped into the perforated holding device and, thus, a turbulent air flow is created through the mass of pellets.
The components of the invention may all be housed in a housing structure that essentially defines the style and configura
Dority & Manning P.A.
Price Carl D.
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