Classifications

• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
  • A47J37/00—Baking; Roasting; Grilling; Frying
  • A47J37/06—Roasters; Grills; Sandwich grills
  • A47J37/07—Roasting devices for outdoor use; Barbecues
  • A47J37/0781—Barbecue tables, e.g. central grilling areas surrounded by an eating table
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
  • A47J37/00—Baking; Roasting; Grilling; Frying
  • A47J37/06—Roasters; Grills; Sandwich grills
  • A47J37/07—Roasting devices for outdoor use; Barbecues
  • A47J37/0704—Roasting devices for outdoor use; Barbecues with horizontal fire box
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
  • A47J37/00—Baking; Roasting; Grilling; Frying
  • A47J37/06—Roasters; Grills; Sandwich grills
  • A47J37/07—Roasting devices for outdoor use; Barbecues
  • A47J37/0786—Accessories
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23B—METHODS OR APPARATUS FOR COMBUSTION USING ONLY SOLID FUEL
  • F23B40/00—Combustion apparatus with driven means for feeding fuel into the combustion chamber
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23B—METHODS OR APPARATUS FOR COMBUSTION USING ONLY SOLID FUEL
  • F23B60/00—Combustion apparatus in which the fuel burns essentially without moving
  • F23B60/02—Combustion apparatus in which the fuel burns essentially without moving with combustion air supplied through a grate

Definitions

• the present invention relates to cookers. 2. Description of Related Art
• earthen includes: pottery, earthenware, stoneware, porcelain, clay, refractory, and fired wares in general, which are more broadly classified as traditional or industrial ceramics (as opposed to advanced ceramics).
• the cooking chamber is typically elongated along its vertical axis, having a base portion and a lid portion. Fuel is placed deep at the bottom of the base portion and food is placed on a grate mounted toward the top of the base portion. As the fuel is combusted, it transfers its heat to the earthen cooking chamber, which in combination with the combusting fuel, transfers heat to the food from below and from all around the food.
• the high heat capacity of the earthen cooking chamber helps the kamado to maintain a steady temperature with a modest amount of fuel when the lid portion remains generally closed.
• the temperature is controlled by incrementally opening or closing vents or dampers located at the top and/or bottom of the cooking chamber, to create a chimney effect.
• the kamado does however have a number of disadvantages. If fuel must be replenished during cooking, typically the lid portion must be opened, the hot grate with the food moved or removed, and then fresh fuel placed deep at the bottom of the chamber. Not only is this process cumbersome, but also it presents an opportunity for a person to be burned while reaching deep into the cooking chamber, which remains hot because of its high heat capacity.
• a comparatively new type of cooker is the pellet grill / barbeque / smoker, perhaps pioneered by Traeger Industries, Inc. as shown in Figure 2 and United States patent 4,823,684 granted April 25, 1989 for a Pellet-fired Barbecue. As shown in Figure 2 this pellet barbeque closely resembles a conventional propane or natural gas grill. An alternative configuration is shown in Figure 3, which more closely resembles a conventional horizontal smoker. Generally these cookers are made from metal, typically stainless steel.
• Pellet cookers combust pellets as fuel.
• Pellets are produced by compressing combustible material, most commonly wood, which has typically first passed through a hammer mill to provide a uniform dough-like mass. Pellets are often made from compacted sawdust or other wastes from sawmilling and other wood products manufacture, or from sources such as whole-tree removal or tree tops and branches leftover after logging. This mass is fed to a press where it is squeezed through a die having holes of the size required (typically 1 ⁇ 4 inch diameter, but sometimes larger). The high pressure of the press causes the temperature of the wood to increase greatly, and the lignin plasticizes slightly forming a natural "glue" that holds the pellet together as it cools.
• Pellets have a regular geometry and small size, allowing automatic feeding with very fine calibration. Pellets are extremely dense and can be produced with a low moisture content (generally below 10%) that allows them to be burned with very high combustion efficiency. They have a uniform density, typically higher than 1 ton per cubic meter and bulk density of about 0.6-0.7 ton per cubic meter. They have good structural strength, and low dust and ash content. It has been estimated that the energy required to manufacture and transport pellets is less than 2% of the energy content of the pellets, so some see them as an environmentally responsible fuel.
• the cooking chamber of a pellet cooker is elongated along its horizontal axis, having a base portion and a lid portion. Fuel is placed in a hopper at one edge of the base portion and conveyed by an auger to a firepot located in the middle of the base portion of the cooking chamber.
• an igniter and a combustion fan are located with respect to the firepot such that the igniter can ignite the pellets in the firepot and the combustion fan can direct air across the ignited pellets.
• Both the igniter and the combustion fan are typically thermostatically-controlled electrical devices, the igniter being for example a high-resistance material connectable to a source of electric power and having an exposed surface that exceeds the fuel's ignition temperature when the igniter is powered.
• Conventional pellet cookers suffer from a number of disadvantages.
• pellet cookers typically must combust a high amount of fuel to maintain a reasonable cooking temperature in the cooking chamber - typically in the neighborhood of four pounds per hour. Even then, pellet cookers have a reputation for a low maximum temperature (typically no more than 500 degrees Fahrenheit) that is insufficient to sear food well.
• the fuel delivery system and the firepot are typically located in the cooking chamber, subject to flame flare-ups and unintended (and perhaps dangerous) combustion.
• the opening between the hopper and the cooking chamber can steal heat from the cooking chamber and compromise the structural integrity of the cooking chamber. Accordingly, what is needed is a cooker that provides at least some of the benefits of kamado and pellet cookers without at least some of their disadvantages.
• the present invention is directed to this need.
• a apparatus for cooking having a cooking chamber having a high heat capacity, and a heating assembly that generates heat energy by combusting pellets, wherein the heating assembly is adapted to connect to the cooking chamber such that the heat energy generated by the heating assembly transfers from the heating assembly to the cooking chamber.
• the cooking chamber may be made from a material having a specific heat capacity at constant pressure that is greater than that of steel, for example greater than 0.7, for example a ceramic material.
• the cooking chamber may be a kamado.
• the heating assembly may be outside the cooking chamber and may be clad to protect users from contacting heat sources.
• the heating assembly may include a fire tube adapted to connect to the cooking chamber such that the heat energy generated by the heating assembly transfers from the heating assembly to the cooking chamber via the fire tube.
• the cooking chamber may include a reinforcement collar adapted to receive the fire tube and a flame diffuser proximate the reinforcement collar.
• the fire tube may include a burn grate at one end, for example a removable burn grate.
• the fire tube may have sides that are perforated with air holes.
• the heating assembly may include a combustion fan connected to the fire tube to urge ambient air into the fire tube.
• the combustion fan may be connected to the fire tube to urge ambient air into the fire tube through the burn grate or through the air holes in the perforated sides.
• the heating assembly may further include a thermostatic switch adapted to detect a temperature and connected to the combustion fan so as to switch off the combustion fan when the detected temperature is less than a threshold temperature.
• the heating assembly may also include a pellet drop tube connected to the fire tube to deliver a plurality of pellets into the fire tube for combustion therein and an ash pan connected to the fire tube to collect ash resulting from the combustion of the plurality of pellets in the fire tube.
• the fire tube may be adapted to urge the delivered plurality of pellets to mound.
• the fire tube and the cooking chamber may form a chimney.
• the cooking chamber may include at least one of a vent and a chimney stack.
• the heating assembly may include a feed auger connected to the pellet drop tube to receive the plurality of pellets and deliver the plurality of pellets to the pellet drop tube.
• the apparatus may further include a hopper connected to the feed auger to store and deliver the plurality of pellets to the feed auger.
• the feed auger may include a motor connected to drive the auger.
• the heating assembly may include an igniter connected to the fire tube to ignite pellets within the fire tube.
• the heating assembly may include an igniter tube that houses the igniter.
• the heating assembly may include an air pump connected to pump air toward the igniter, for example through the igniter tube.
• the heating assembly may further include a user-operable control for activating at least one of: the auger motor, the igniter, the air pump and the combustion fan, for example switching from an off-state to an on-state or varying output magnitude, including varying output magnitude over a user-selectable range.
• Figure 1 Is a front sectional view of a prior art kamado cooker.
• Figure 2 Is a top front left oblique outline view of a first prior art pellet cooker.
• Figure 3 Is a top front left oblique sectional view of a second prior art pellet cooker.
• Figure 4 Is a top front right oblique sectional view of an embodiment of a pellet kamado cooker according to aspects of the present invention, the cooker having a cooking chamber with a base portion and a lid portion and having a hopper and a heating assembly located outside the cooking chamber.
• Figure 5 Is a top front right oblique view the cooker of Figure 4, the lid portion and the hopper being in a closed position.
• Figure 6 Is a top front right oblique view the cooker of Figure 4, the lid portion and the hopper being in an open position.
• Figure 7 Is a front elevation view of the cooker of Figure 4.
• Figure 8 Is a rear elevation view of the cooker of Figure 4.
• Figure 9 Is a top plan view of the cooker of Figure 4.
• Figure 10 Is a left elevation view of the cooker of Figure 4.
• Figure 11 Is a right elevation view of the cooker of Figure 4.
• Figure 12 Is a front elevation sectional view of the cooker of Figure 4.
• Figure 13 Is a right elevation sectional view of the cooker of Figure 4.
• Figure 14 Is a front elevation sectional view of the heating assembly of
• Figure 15 Is a top front right oblique detail sectional view of the heating assembly of Figure 4.
• Figure 16 Is a top plan sectional view detailing the heating assembly of
• FIG. 4 showing an igniter in an igniter tube, and further including an auger timing module, an igniter air pump and a combustion fan.
• Figure 17 Is a schematic view of the electrical interconnection of the igniter the auger timing module with the auger motor, the igniter, the air pump, and the combustion fan in the heating assembly.
• FIGS 4-17 show a cooking apparatus (hereinafter a "cooker") 100 according to embodiments of the present invention.
• the cooker 100 is suitable for barbequing, smoking (hot, cold or otherwise), grilling, searing, roasting, baking and the like, among other uses, and terms such as “cook' and “cooking” will be used herein to have any and all such meanings unless otherwise specified, and a cooker 100 will be such an apparatus for cooking.
• the cooker 100 includes a kamado-style cooking chamber 102, in this embodiment formed from an earthen material, for example a ceramic shell bottom (hereinafter base portion 104) and a mating ceramic shell top (hereinafter lid portion 106) connected together by a hinge 108, the lid portion 106 having a handle 110 to assist a user to move the lid portion 106 between a closed position ( Figure 5) and an open position ( Figure 6).
• a kamado-style cooking chamber 102 formed from an earthen material, for example a ceramic shell bottom (hereinafter base portion 104) and a mating ceramic shell top (hereinafter lid portion 106) connected together by a hinge 108, the lid portion 106 having a handle 110 to assist a user to move the lid portion 106 between a closed position ( Figure 5) and an open position (Figure 6).
• kamado-style connotes a cooking chamber 102 with a high heat capacity; those skilled in the art will recognize that such a cooking chamber 102 might be constructed with other than earthen material.
• high heat capacity denotes a specific heat capacity at
• c p constant pressure
• a suitable material for the cooking chamber 102 must also have a melting temperature, a sublimation temperature and a combustion temperature greater than the operating temperature inside the cooking chamber 102.
• a suitable material will not have a high thermal conductivity; for example, although aluminum has a specific heat capacity greater than 0.7 (0.9), its low melting temperature (660 °C) and its high
• the cooking chamber 102 is elongated along its vertical axis, with a chimney stack 112 in its lid portion 106, in this embodiment shown protected with a rain cap 114, and a vent 116, in this embodiment having a damper 118, in its base portion 104, in this embodiment in a sidewall proximate the bottom.
• This orientation and arrangement of venting encourages chimney effect airflow, to encourage fuel combustion and heat transfer from the combusting fuel to the cooking chamber 102.
• the cooking chamber 102 conveniently supports opposing side shelves 120 and is supported itself by a wheeled cart 122.
• the cooker 100 may include a thermometer having a display mounted on the outside of the cooking chamber 102 and a probe that extends into the cooking chamber 102 for measuring the temperature therewithin.
• the base portion 104 supports within it a cooking grill 124, a heat diffuser 126 below the cooking grill 124, and a flame diffuser 128 below the heat diffuser 126.
• the cooking grill 124 and the heat diffuser 126 are proximate the top of the base portion 104 and the flame diffuser 128 is proximate the bottom of the base portion 104.
• the cooker 100 also includes a fuel hopper 130 and a heating assembly 132 that includes a feed auger 134, a pellet drop tube 136, a fire tube 138 and an ash pan 140.
• the cooking chamber 102 and the fire tube 138 are adapted so that the narrow fire tube 138 passes into the cooking chamber 102 through a mating small passage in its base portion 104, proximate the flame diffuser 128.
• the passage is soundly located at the centre of the bottom of the base portion 104 and is reinforced, in this embodiment with a reinforcement collar 142.
• the flame diffuser 128 provides further reinforcement to the base portion 104.
• this external arrangement of the hopper 130 and the heating assembly 132 provides a convenient way to transfer the heat energy generated from pellet combustion into the cooking chamber 102 without having to fit either the hopper 130 or the heating assembly 132 (or a significant portion thereof) into the cooking chamber 102, which would take up space within the cooking chamber 102 and raise safety concerns about grease fires, among other issues.
• Locating only the hopper 130 outside the cooking chamber 102 is more safe and convenient for the user than locating it inside; however, that arrangement is still less desirable than externally locating both the hopper 130 and the heating assembly 132, because for pellet combustion to occur within the cooking chamber 102, the pellets would have to be conveyed from the hopper 130 into the cooking chamber 102 to the heating assembly 132 through a wall in the cooking chamber 102, which arrangement would require a sufficiently significant hole in the wall as to steal heat from the cooking chamber 102 and undermine the structural integrity of the fragile earthen material.
• the hopper 130 extends steeply downward from one of the side shelves 120 to a location below the base portion 104 of the cooking chamber 102.
• the hopper 130 includes a hopper lid 144 in the one of the side shelves 120, openable to allow a user to load pellets into the hopper 130 and closeable to protect the pellets in the hopper 130 from contamination and to provide a work surface on the one of the side shelves 120.
• the hopper 130 includes a dump gate 146 for unloading unused pellets, for example for winterizing the cooker 100.
• the feed auger 134 inclines upward from the bottom of the hopper 130 toward the base portion 104 of the cooking chamber 102.
• the bottom of the auger 134 is connected to receive pellets from the hopper 130 and the top of the auger 134 is connected to a drive motor 148.
• the drive parameters of the motor 148 (for example speed or duty cycle) - and hence the pellet feed rate of the driven auger 134 - are set by a user-operable control, for example a knob 150 conveniently mounted on one of the side shelves 120 ( Figure 5-7, 9).
• the knob 150 has an "off' position and a range of "on" positions corresponding to a range of auger 134 feed rates, and as a consequence corresponding to a range of cooking chamber 102 temperatures.
• a scale of the corresponding temperatures can be located adjacent the knob 150.
• the user-operable control also includes a range switch 152, for selecting among predetermined ranges for the knob, for example a range of low values and a range of high values.
• a range switch 152 for selecting among predetermined ranges for the knob, for example a range of low values and a range of high values.
• the low range might cover values that correspond to smoking temperatures and the high range might cover values that correspond to grilling temperatures.
• the knob 150 could be implemented in a number of ways, for example as a combination of an on/off switch and a potentiometer for supplying varying amounts of electricity to drive the motor 148.
• one implementation of the user- operable control includes an auger timing module 154 that is connected to receive an input signal from the knob 150 and range switch 152 and to generate an output signal to the motor 148 to set a duty cycle for the pellet feed.
• the timer module includes a model TRS51 A1 1 S2 digital encapsulated repeat cycle time delay module by Infitec Inc., having a place of business at 6500 Badgley Road, East Syracuse, NY 13057 USA. Attached as Appendix A to this specification is a manufacturer's data sheet for the Infitec TRS51A1 1 S2 digital encapsulated repeat cycle time delay module.
• the pellet drop tube 136 is connected between the top of the feed auger 134 and the fire tube 138, to supply pellets from the auger 134 to the fire tube 138.
• the bottom of the fire tube 138 is formed as a removable burn grate 156 that provides primary air holes 158 to aid combustion.
• the sides of the fire tube 138 are perforated with secondary air holes 160 to further aid combustion.
• the ash pan 140 is located beneath the fire tube 138 to catch uncombusted ash that falls through the burn grate 156.
• the heating assembly 132 can further include an igniter 162, shown located near the burn grate 156 in the fire tube 138 and housed within an igniter tube 164.
• an air pump 166 is connected to pump ambient air toward the igniter 162, for example through the igniter tube 164, to improve the combustion environment proximate the igniter 162 to encourage faster pellet ignition.
• a combustion fan 168 may be located proximate the fire tube 138 to urge ambient air through the primary air holes 158 and/or secondary air holes 160 to improve the combustion environment in the fire tube 138 and/or to pressurize the fire tube 138 to encourage convection and to pressurize the ash pan 140 to trap ash.
• the igniter 162, the air pump 166 and the combustion fan 168 may be connected to an electricity source by a user-operable control, in this embodiment the control knob 150, such that the three devices are powered on whenever the knob 150 is in a position other than its off position.
• the combustion fan 168 may additionally include a thermostatic switch 170 that prevents the combustion fan 168 from operating below a threshold temperature; for example, the thermostatic switch 170 might detect the temperature on, near or in the fire tube 138 or the igniter tube 164 and the threshold temperature might be 160 degrees Fahrenheit.
• a thermostatic switch 170 that prevents the combustion fan 168 from operating below a threshold temperature; for example, the thermostatic switch 170 might detect the temperature on, near or in the fire tube 138 or the igniter tube 164 and the threshold temperature might be 160 degrees Fahrenheit.
• the igniter 162, the air pump 166 and the combustion fan 168 are controlled in a simple "on” or “off' manner; however, those skilled in the art will recognize that they could be controlled to have variable output magnitude depending on system parameters, for example temperature, air flow or concentration of combustion chemicals, for example as measured in the fire tube 138 or the cooking chamber 102.
• Figure 17 illustrates one suitable electrical interconnection of the auger timing module 154 with its inputs and its outputs in the heating assembly 132, namely the knob 150 and range the range switch 152 (the user-operable controls) and the thermostatic switch 170 as inputs and the auger motor 148, the igniter 162, the air pump 166, and the combustion fan 168 as outputs.
• airflow for combustion can be encouraged by (a) configuring the fire tube 138 and in particular the burn grate 156 to urge the pellets to mound in a formation that permits good airflow between pellets and (b) configuring the cooking chamber 702 (and its chimney stack 112, vent 116, heat diffuser 726 and flame diffusers 728) and the fire tube 738 (and its primary air holes 758 and secondary air holes 760) for strong chimney effect.
• the heating assembly 732 is clad for protection and to protect the user from contacting heat sources.
• a user To operate the cooker 700, a user lifts the hopper lid 744 and fills the hopper 730 with fuel pellets, closing the hopper lid 744 when he is finished.
• a user might wish to fill the hopper 730 with at least the amount of fuel he expects to use for the current cooking tasks. Nevertheless, if additional pellets were to be needed, it is simple and safe to add more fuel pellets to the hopper 730, even in the middle of cooking. Gravity draws the pellets to the bottom of the hopper 730, thus supplying pellets to the auger 734 at its lower end.
• the user would then turn the control knob 750 from the "off' position to an "on" position that corresponds to the desired temperature for the cooking chamber 702 - and more directly, that corresponds to the auger 734 feed rate that delivers sufficient pellet fuel for combustion to produce that temperature.
• electricity would be supplied to the auger motor 748 (in this embodiment via the auger timing 754 module) such that the auger 734 would be engaged to feed substantially uniform pellets at that predetermined feed rate.
• Operation of the knob 150 would also cause electricity to be supplied to the igniter 162, causing the igniter 162 to heat to a temperature sufficient to ignite proximate pellets dropped by the auger 134 into the fire tube 138 via the pellet drop tube 136.
• electricity would also be supplied to the air pump 166, causing it to supply air to the region around the igniter 162 to encourage combustion of proximate pellets.
• operation of the knob 150 would also cause electricity to be supplied to the combustion fan 168, such that the combustion fan 168 would supply still more air to the fire tube 138 via the primary air holes 158 and/or secondary air holes 160.
• the combustion fan 168 would only supply air when a threshold temperature (for example 160 degrees Fahrenheit) in a region (for example inside the igniter tube 164 adjacent the igniter 162) had been exceeded, such that the combustion fan 168 was activated when most useful.
• a threshold temperature for example 160 degrees Fahrenheit
• there might be a designated ignition position for the control knob 150 that corresponds to operating parameters for the auger 134 (motor 148), the igniter 162, the air pump 166, the combustion fan 168 that particularly encourage initial ignition of the pellets.
• the knob 150 might have a setting that supplies electricity to the combustion fan 168 but not the auger 134, the igniter 162 and the air pump 166, this knob 150 setting would correspond to a cool down mode where no further pellets are being supplied to the fire tube 138 but the combustion fan 168 encourages the pellets currently in the fire tube 138 to combust as fully and efficiently as practical.
• the user might further adjust the operating parameters of the heating assembly 132 by toggling the thermostatic switch 170, thereby selecting a range for the knob 150.
• the ceramic cooking chamber 102 had silicate walls with a nominal thickness of 0.875 inches that contained a nominal volume of 3.9 cubic feet,
• the pellets used were food-grade wood pellets that are believed to have had an energy density in a range between 7500 British thermal units per pound and 9200 British thermal units per pound, and more particularly were Traeger ® brand hickory pellets from Traeger Pellet Grills, LLC, having a place of business at 9445 SW Ridder Rd, Wilsonville, OR 97070, United States of America, and
• the heating assembly 132 included both an air pump 166 and a combustion fan 168 with a thermostatic switch 170 having a threshold temperature of 160 degrees Fahrenheit, the following results were observed: Pel let Result in
• ceramic means a traditional or industrial ceramic material such as clay, earthenware, stoneware, porcelain, refractory, pottery, and fired wares in general, and includes functional equivalents that have traditional ceramic properties that support the present teaching (for example high specific heat capacity, high melting point, low thermal conductivity), including advanced ceramic materials and non-ceramic materials.
• this cooking chamber 702 has a high heat capacity in comparison to non-kamado-style cookers 100, such as kettle barbeques, bullet smokers, gas grills, and pellet cookers 100 fabricated from sheets of stainless steel and the like.
• the cooking chamber 102 had a
• the heat capacity of the cooking chamber 102 is nominally 44
• a closed-loop control system for example including a PID (Proportional/lntegral/Derivative) controller, could be added to control at least some of the auger motor 748, the igniter 762, the air pump 766, and the combustion fan 768 (perhaps as variable-output devices), if it were decided that tighter temperature tolerances warranted the additional cost and complexity.
• PID Proportional/lntegral/Derivative
• Pellets fed into the fire tube 738 and mounding on the burn grate 756 are ignited by the igniter 762 or adjacent ignited pellets, their combustion drawing outside air through the primary air holes 758 in the burn grate 756 and secondary air holes 760 in the walls of the fire tube 738 to encourage the combustion.
• Uncombusted waste product, such as ash falls through the burn grate 756 into the ash pan 740.
• Heat energy for example in the form of hot flue gases, flame, and the heated fire tube 738 itself, is transferred by the fire tube 738, for example by convection, radiation and conduction, from the heating assembly 732 into the base portion 704 of the cooking chamber 702 proximate the flame diffuser 728, where at least some of that heat energy is transferred to the walls of the cooking chamber 102 and to the heat diffuser 126 and ultimately to food on the cooking grill 124.
• the heat is distributed substantially evenly due to the round shape of the cooking chamber 102 and the elongated vertical distance between the fire tube 138 and the cooking grill 124.
• the elongated vertical distance also encourages a chimney effect to urge upward convection currents.
• the high heat capacity of the cooking chamber 102 walls encourages temperature stability within the cooking chamber 102.
• This arrangement of locating the heating assembly 132 outside of (but in communication with) the cooking chamber 102 produces a safer cooking environment within the cooking chamber 102, reducing the chance and severity of grease fires or flame flare-ups.
• the flame diffuser 128, the heat diffuser 126 and the extension of the top end of the fire tube 138 above the bottom inside surface of the cooking chamber 102, where grease might pool, provide further safety in this regard.
• this placement of the heating assembly 132 below the cooking chamber 102 and behind cladding keeps hot sources further away from human contact than a regular outdoor cooker, such as a charcoal grill.
• the user adjusts the control knob 150 and/or the range switch 152 to adjust the feed of pellets into the fire tube 138 and allows the cooking chamber 102 to settle at the corresponding temperature.
• the cooking chamber 102 may be made using non-earthen materials that have functional similarities.

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• Engineering & Computer Science (AREA)
• Food Science & Technology (AREA)
• Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Thermal Sciences (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Baking, Grill, Roasting (AREA)

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Cited By (35)

Citations (6)

• 2013
  • 2013-02-08 WO PCT/CA2013/050100 patent/WO2013116946A1/fr not_active Ceased

Patent Citations (6)

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