The disclosure relates generally to pellet-fired heating systems, and associated appliances such as cooking grills.
Wood pellet grills are used as outdoor cooking grills in which fuel pellets and air are fed to a fire pot in which combustion of the pellets occurs. The heat generated from the combustion of the pellets is used to heat a cooking area of the pellet grill. Pellet grill temperatures are typically controlled by controlling the amount of fuel being consumed and by regulating of airflow to the fire pot. While pellet grills have advantageous features and are often preferred over other types of grills, some existing pellet grills have drawbacks such as non-uniform heating across larger cooking surfaces and the inability to generate temperatures that are high enough for searing food. Improvement is desirable.
In one aspect, the disclosure describes a cooking grill comprising:
The radiator may be a first radiator. The internal passage may be a first internal passage and the discharge outlet may be a first discharge outlet. The system may comprise:
The valve may be disposed inside the combustion chamber.
A straight portion of the first internal passage of the first radiator may be substantially parallel to a straight portion of the second internal passage of the second radiator.
The cooking grill may comprise a conveyor in communication with the fuel inlet of the combustion chamber and operable to deliver the fuel pellets to the combustion chamber.
The conveyor may be disposed inside a conduit establishing fluid communication between the blower and the air inlet.
The radiator may have an elongated shape. The discharge outlet may be one of a plurality of discharge outlets distributed along the radiator.
The cooking grill may comprise a heat deflector adjacent the radiator. The heat deflector may intersect an axis defining orientation of the discharge outlet.
The fuel pellets may be a first fuel of a first fuel type and the cooking grill may include a burner for heating the cooking chamber. The burner may be configured to facilitate combustion of a second fuel of a second fuel type different from the first fuel type.
The burner may be a gas burner.
The burner and the radiator may be disposed inside the cooking chamber.
The burner and the radiator may be elongated. The burner and the radiator may be oriented transversely to each other.
Embodiments may include combinations of the above features.
In another aspect, the disclosure describes an outdoor space heater comprising:
The outdoor space heater may comprise an air-permeable cover enclosing the heating volume.
The cover may include one or more walls made of a metallic mesh.
The outdoor space heater may comprise a base and the heating volume may be disposed vertically above the base.
The radiator may include a straight tubular portion extending vertically.
The radiator may be a first radiator. The straight tubular portion may be a first straight tubular portion. The outdoor space heater may include a second radiator extending into the heating volume. The second radiator may include a second straight tubular portion substantially parallel to the first straight tubular portion.
The outdoor space heater may comprise a heat deflector adjacent the radiator. The heat deflector may intersect an axis defining orientation of the discharge outlet.
The radiator may have a helical tubular portion.
The radiator may be a first radiator. The helical tubular portion may be a first helical tubular portion. The outdoor space heater may include a second radiator extending into the heating volume. The second radiator may include a second helical tubular portion intertwined with the first helical tubular portion.
The outdoor space heater may comprise an ash receptacle for receiving ash from the combustion chamber.
The outdoor space heater may comprise:
Embodiments may include combinations of the above features.
The radiator may be a first radiator. The internal passage may be a first internal passage and the discharge outlet may be a first discharge outlet. The system may comprise:
The valve may be disposed inside the combustion chamber.
A straight portion of the first internal passage of the first radiator may be substantially parallel to a straight portion of the second internal passage of the second radiator.
The pellet-fired heating system may comprise a conveyor in communication with the fuel inlet of the combustion chamber and operable to deliver the fuel pellets to the combustion chamber.
The conveyor may be disposed inside a conduit establishing fluid communication between the blower and the air inlet.
The radiator may have an elongated shape. The discharge outlet may be one of a plurality of discharge outlets distributed along the radiator.
The radiator may have a proximal end proximal to the combustion chamber and a distal end distal of the combustion chamber. The distal end of the radiator may be capped.
The internal passage may include a first straight portion, a bend and a second straight portion disposed series.
The first and second straight portions may be substantially perpendicular.
The first and second straight portions may be substantially parallel.
The pellet-fired heating system may comprise a heat deflector associated with the radiator. The heat deflector may intersect an axis defining orientation of the discharge outlet.
The fuel pellets may be a first fuel of a first fuel type and the pellet-fired heating system may include a burner for heating the space. The burner may be configured to facilitate combustion of a second fuel of a second fuel type different from the first fuel type.
The burner may be a gas burner.
The burner and the radiator may be elongated. The burner and the radiator may be oriented transversely to each other.
Embodiments may include combinations of the above features.
In a further aspect, the disclosure describes a method of heating with fuel pellets. The method comprises:
The radiator may be a first radiator and the method may comprise:
The method may comprise adjusting the proportions of the combustion gas respectively received into the first radiator and the second radiator.
The method may comprise using a common blower to push the air to the combustion chamber and to push the combustion gas into the radiator.
The method may comprise pushing a flame generated in the combustion chamber into the radiator.
The method may comprise discharging the flame into the space from a discharge outlet formed in the radiator.
The method may comprise deflecting heat released from the discharge outlet.
The space may be a cooking chamber of a cooking grill.
The fuel pellets may be a first fuel of a first fuel type and the method may include heating the space using a second fuel of a second fuel type different from the first fuel type.
The second fuel type may be a fluid.
The method may comprise combusting the second fuel inside the space.
The method may comprise discharging the combustion gas from the radiator into the space.
Embodiments may include combinations of the above features.
Further details of these and other aspects of the subject matter of this application will be apparent from the detailed description included below and the drawings.
Reference is now made to the accompanying drawings, in which:
The following disclosure describes pellet-fired heating systems, methods and associated appliances such as cooking grills. In various embodiments, the systems and methods described herein make use of one or more radiators for heating a space such as a cooking chamber. In some embodiments, the systems and methods described herein may promote relatively uniform heating over larger cooking surfaces and may also facilitate higher temperatures that may be suitable for searing food. In some embodiments, the systems and methods described herein may facilitate selective heating of different zones within a space to be heated. Some embodiments of the heating systems described herein may also be used in other appliances such as outdoor space heaters and fireplaces for example.
Hereinafter, the term “connected” or “coupled to” may include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements). The term “substantially” as used herein may be applied to modify any quantitative representation which could permissibly vary without resulting in a change in the basic function to which it is related.
Aspects of various embodiments are described below through reference to the drawings.
Radiators 14A, 14B may each have an elongated shape and a plurality of discharge outlets 18A, 18B distributed along the elongated shape. In various embodiments, discharge outlet 18A, 18B may be through holes of circular or other shape defined in radiators 14A, 14B. In some embodiments, discharge outlets 18A, 18B may include one or more through slits defined in radiators 14A, 14B.
Radiators 14A, 14B may be tubes that have a substantially circular cross-sectional profile. Alternatively, radiators 14A, 14B may have a non-circular (e.g., oval, rectangular) cross-sectional profile. Radiators 14A, 14B may have substantially identical or different cross-sectional profiles. Radiators 14A, 14B may be made from a metallic material such as (e.g., stainless) steel, other alloy(s) or other material suitable for the operating conditions. Radiators 14A, 14B may be formed by cutting, bending and/or welding tubular pieces together to achieve the desired configuration of radiators 14A, 14B. Discharge outlets 18A, 18B may be drilled into the tubular pieces.
Radiators 14A, 14B may be shaped and configured (e.g., routed) to have any layout that accommodates the size and configuration of the space to be heated. Radiators 14A, 14B may have straight and/or curved portions. In some embodiments, radiators 14A, 14B may have respective proximal ends 20A proximal to combustion chamber 12 and respective distal ends 22A distal of combustion chamber 12. Radiators 14A, 14B and their associated internal passages 16 may have respective first straight portions 24A, 24B, bends 26A, 26B and second straight portions 28A, 28B disposed series. In some embodiments, second straight portion 28A of first radiator 14A may be substantially parallel to second straight portion 28B of second radiator 14B.
Radiators 14A, 14B may be attached to combustion chamber 12 or other structure of system 10 by any suitable means such as welding or fastening. In some embodiments, radiators 14A, 14B may be removably fastened to combustion chamber 12 or other structure.
In some embodiments, radiators 14A, 14B could be connected together so that respective internal passages 16 are combined to form a loop instead of separate branches. Alternatively, distal ends 22A, 22B of respective radiators 14A, 14B may be capped so that the combustion gas and flames may be forced to exit radiators 14A, 14B via discharge openings 18A, 18B. The number, size and location of discharge openings 18A, 18B may be selected based on an expected flow rate of combustion gas pushed into radiators 14A, 14B and desired heat distribution and performance. In some situations, it may be desirable that the configuration of discharge openings 18A, 18B be selected so that, in use, each internal passage 16 serves as a plenum in which the combustion gas is accumulated and discharged via discharge openings 18A, 18B at relatively similar flow rates. Such relatively even distribution of combustion gas among discharge openings 18A, 18B may promote a relatively uniform heating along radiators 14A, 14B and throughout the space to be heated. Desired configurations of discharge openings 18A, 18B for different applications and situations may be determined experimentally or using numerical modeling and simulation. As an example, the discharge openings 18A, 18B may be about 0.375″ (1 cm) in diameter, and the discharge openings 18A, 18B may be spaced about 2″ (5 cm) apart along the radiators 14A, 14B, from center to center. It is understood that other hole diameters, shapes and spacings could also be used.
Pellet system 10 may include blower 38 in fluid communication with one or more air inlets 40 (referred hereinafter in the singular) of combustion chamber 12 and configured to draw ambient air and push the air into combustion chamber 12 via air inlet 40. Blower 38 may be electrically driven. Blower 38 may include a fan and an electric motor. The operating speed of blower 38 may be adjustable in order to vary the flow rate of air provided to combustion chamber 12. For example, the operating speed of conveyor 30 and of blower 38 may be coordinated so that the flow rate of air delivered to combustion chamber 12 may be coordinated with the feed rate of pellets delivered to combustion chamber 12 to sustain the combustion process. The flow of air delivered to combustion chamber 12 is indicated by arrow A.
In some embodiments of pellet system 10, conveyor 30 may be disposed inside air conduit 44 establishing fluid communication between blower 38 and air inlet 40 if combustion chamber 12. For example, conveyor 30 and its outer casing may define a fuel passage that is separate from the air passage defined by air conduit 44 but that extends within air conduit 44. For example, the fuel passage may extend substantially coaxially with air conduit 44. In other words, conveyor 30 may define a smaller tube extending within and along a larger tube (i.e. air conduit 44) defining an annular air passage. Alternatively, conveyor 30 may be disposed outside of air conduit 44.
Combustion chamber 12 may include one or more combustion gas outlets 42 establishing fluid communication between combustion chamber 12 and internal passages 16 of radiators 14A, 14B. During operation of pellet system 10, blower 38 may push air into combustion chamber 12 and also cause the combustion gas to be pushed out of combustion chamber 12 via combustion gas outlet(s) 42 and into radiator(s) 14A, 14B. For example, the flow of combustion gas delivered to (e.g., pushed into) radiator 14A is indicated by arrow CG1.
Pellet system 10 may include a hot surface igniter also known as a “Hot Rod” igniter, or other type of igniter suitable for initiating and/or maintaining combustion inside combustion chamber 12.
In some embodiments, method 1000 may include receiving proportions of the combustion gas from combustion chamber 12 respectively into first radiator 14A and second radiator 14B extending into the space. The heat carried by the combustion gas may be radiated via both radiators 14A, 14B. Similarly, the combustion gas may be discharged from discharge outlets 18A, 18B of both radiators 14A, 14B. The combustion gas may be discharged from radiators 14A, 14B and into the space to be heated.
In some embodiments, a single common blower 38 may be used to perform both functions of pushing the air to combustion chamber 12 and also pushing the combustion gas into radiators 14A, 14B. For example, as shown in
Radiators 214A, 214B (and their associated internal passages) may have respective first straight portions 224A, 224B, bends 226A, 226B and second straight portions 228A, 228B disposed series. In some embodiments, first straight portions 224A, 224B may be substantially parallel to each other. In some embodiments, second straight portions 228A, 228B may be substantially parallel to each other. In some embodiments, first straight portion 224A may be substantially parallel to second straight portion 228A. Similarly, first straight portion 224B may be substantially parallel to second straight portion 228B. Radiators 214A, 214B and their associated internal passages may each define a zig-zag pattern extending substantially vertically. Radiators 214A, 214B may each have perforated straight portions that are connected in series and that are oriented about 180° apart. In some embodiments, radiators 214A, 214B may be laterally and vertically offset from each other to provide an increased laterally-facing frontal heating area.
Radiators 314A, 314B (and their associated internal passages) may have respective first straight portions 324A, 324B, bends 326A, 326B and second straight portions 328A, 328B disposed series. In some embodiments, first straight portions 324A, 324B may be substantially perpendicular to each other. In some embodiments, second straight portions 328A, 328B may be substantially perpendicular to each other. In some embodiments, first straight portion 324A may be substantially perpendicular to second straight portion 328A. Similarly, first straight portion 324B may be substantially perpendicular to second straight portion 328B. Radiators 314A, 314B and their associated internal passages may each define a zig-zag pattern extending substantially vertically from combustion chamber 12. Radiators 314A, 314B may each have perforated straight portions that are connected in series and that are oriented about 90° apart. In some embodiments, radiators 314A, 314B may be laterally offset from each other to provide an increased laterally-facing frontal heating area.
Valve 450 may be operable (e.g., actuatable) to adjust the proportions of the combustion gas respectively received (e.g., pushed) into first radiator 414A and second radiator 414B. In some embodiments, valve 450 may include baffle 452 movably mounted inside of combustion chamber 412. For example, baffle 452 may be rotatable about pivot pin 454 that may be engaged with cover 415. Slide pin 456 may be attached to baffle 425 and movably received through slot 458 defined in cover 415. Slot 458 may have an arcuate shape having a center substantially coaxial with pivot pin 454 so that movement of slide pin 456 along slot 458 may cause rotational movement of baffle 452 as represented by arrow V.
In order to adjust the position of baffle 452, slide pin 456 may be moved manually along slot 458 by an operator of pellet system 410. In some embodiments, where pellet system 410 is integrated into a cooking chamber, baffle 452 may be manually actuatable by the operator from a safe location via a suitable linkage, rod, lever or knob operatively coupled to baffle 452. Alternatively, baffle 452 may be operatively coupled to an electric motor controllable by the operator via a suitable interface.
In some embodiments, valve 450 may be positioned at intermediate positions between those shown in
The use of valve 450 may allow for controlling the amount of heat being delivered to different zones within the space (e.g., cooking chamber 46). It is understood that pellet system 410 may include more than two radiators 414A, 414B and that different configurations of valve 450 may be implemented to vary proportions of combustion gas delivered to more than two radiators 414A, 414B.
In some embodiments, pellet system 10 may be electrically-powered and may include power cord 62 configured to connect into a household electrical outlet. Pellet system 10 may also include (e.g., digital) controller 64 operatively coupled to motor 36 and fan 38 (shown in
Gas system 60 may include one or more gas burners 66A-66C for heating the space to be heated. Gas burners 66A-66C may be fluidly connectable to a source of propane or natural gas via gas line 68 and respective valves controllable via knobs 70A-70C. In some embodiments, gas burners 66A-66C may be fluidly connectable to a fuel reservoir (e.g., propane tank) via pressure regulator 69 which serves to regulate (e.g., reduce) the pressure of the gas being supplied to gas burners 66A-66C from the fuel reservoir. Each knob 70A-70C may be associated with a respective gas burner 66A-66C so that gas flow to gas burners 66A-66C may be individually controlled. Alternatively, a single one of knobs 70A-70C may associated with a plurality of gas burners 66A-66C.
A exemplary cross-sectional schematic representation of heat deflector 72 together with first radiator 14A is shown in the inset of
During operation, cooking grill 148 may provide some versatility such that the same cooking grill 148 may be used either as a pellet grill or as a gas grill depending the type of cooking task at hand and the operator's preference. For example, pellet system 10 and gas system 60 may be operable independently from each other. Pellet system 10 and gas system 60 may be operated at different times. Alternatively, both pellet system 10 and gas system 60 may be operated simultaneously if desired. Such simultaneous operation of pellet system 10 and gas system 60 may be desired when it is desired to cook objects in the cooking grill 148 with the gas system 60, while also infusing smoke or smoke flavouring from the pellet system 10 operation.
Outdoor space heater 600 may include cover 616 enclosing heating volume 646 (chamber). Cover 616 may be air-permeable to allow combustion gas released from radiators 614A-614C out of heating volume 646 and also allow heat to be radiated out of heating volume 646. Cover 616 may serve as a safety screen that hinders direct physical contact of radiators 614A-614C by people or other objects outside of heating volume 646. Cover 616 may include one or more side walls with openings formed therethrough. For example, wall(s) of cover 616 may include a metallic wire mesh defining the openings or may otherwise be perforated. The openings may be of uniform size and shape or may be of different sizes and/or shape.
Cover 616 may include heat deflecting upper cap 620 which may be substantially air-impermeable. Cap 620 may include an unperforated metallic sheet or plate that hinders heat from escaping upwardly from heating volume 646. It is understood that the configuration of cover 616 may be selected based on the desired escape direction of radiant heat from heating volume 646 by selecting the size and location of perforated and unperforated walls of cover 616.
Cover 616 may have a generally cylindrical or other shape and may enclose radiators 614A-614C disposed within heating volume 646. Cover 616 and associated heating volume 646 may be disposed vertically above base 622 of outdoor space heater 600. For example, cover 616 may be adapted to interface (i.e., engage) with an upper side of housing 624.
Housing 624 may house combustion chamber 612 and optionally other components of pellet system 610. Housing 624 may include a cut-out for accommodating (e.g., digital) controller 664 operatively coupled to pellet system 610 so that operating parameters such as heat output and run time of pellet system 610 may be controlled. Controller 664 may provide an operator interface for adjusting and/or monitoring one or more operating parameters of pellet system 610.
Base 622 may include ash receptacle 626 located beneath combustion chamber 612 for receiving ash (e.g., spent pellet fuel) from combustion chamber 612. In some embodiments, ash receptacle 626 may be defined by a drawer or tray which is movably received into base 622 and which extends under combustion chamber 612. In some embodiments, a floor of combustion chamber 612 may include one or more apertures establishing communication between the interior of combustion chamber 612 and ash receptacle 626. The ash formed inside of combustion chamber 612 may fall into ash receptacle 626 via the aperture(s) due to the influence of gravity as shown by arrow labeled as “ASH”. The aperture(s) in the floor of combustion chamber 612 may be sized to permit the passage of ash particles while preventing pellets from falling into ash receptacle 626. In some embodiments, the floor may include a screen or a perforated sheet.
Radiators 614A-614C may be elongated and may each include a straight tubular portion that extends substantially vertically within heating volume 646. The straight tubular portions of radiators 614A-614C may be substantially parallel to one another. In some embodiments, the straight tubular portions may each have a length that represents at least a majority of the total length of the respective radiator 614A-614C. In some embodiments, radiators 614A-6140 may have bends and additional straight tubular portions.
Outdoor space heater 600 may include heat deflectors 672A-672C that may be respectively disposed adjacent respective radiators 614A-6140. Heat deflectors 672A-672C may be attached to radiators 614A-6140 and positioned to intersect an axis defining orientation of discharge outlets 618 (shown in
During operation of outdoor space heater 600, combustion gas and flames generated inside combustion chamber 612 from the combustion of pellets may be pushed into radiators 614A-6140 using a blower. Radiators 614A-614C may become heated by the combustions gas and then radiate heat in the outdoor space via the perforated side walls of cover 616.
Cover 716 is shown as having a tapered rectangular shape (e.g., square-based pyramid) and may have one or more air-permeable (e.g., perforated, meshed) side walls. Cover 716 may enclose radiators 714A, 714B disposed within heating volume 746 (chamber). Cover 716 may include heat deflecting upper cap 720 which may be substantially air-impermeable. Cap 720 may include an unperforated metallic sheet or plate that hinders heat from escaping upwardly from heating volume 746.
Housing 724 may house combustion chamber 712 (shown in
Base 722 may include ash receptacle 726 located beneath combustion chamber 712 for receiving ash (e.g., spent pellet fuel) from combustion chamber 712. In some embodiments, ash receptacle 726 may be defined by a drawer or tray which is movably received into base 722 and which extends under combustion chamber 712. In some embodiments, a floor of combustion chamber 712 may include one or more apertures establishing communication between the interior of combustion chamber 712 and ash receptacle 726. The ash formed inside of combustion chamber 712 may fall into ash receptacle 726 via the aperture(s) due to the influence of gravity as shown by arrow labeled as “ASH”. The aperture(s) in the floor of combustion chamber 712 may be sized to permit the passage of ash particles while preventing pellets from falling into ash receptacle 726. In some embodiments, the floor may include a screen or a perforated sheet.
Radiators 714A, 714B may each include one or more straight tubular portions, bends and/or helical tubular portions. In some embodiments, outdoor space heater 700 may include one or more radiators 714A, 714B having respective helical tubular portions where each helical tubular portion may have a length that represents at least a majority of the total length of the respective radiator 714A, 714B. In some embodiments, the helical tubular portions of radiators 714A, 714B may be intertwined about a central axis that extends substantially vertically above base 722. Radiators 714A, 714B may each have one or more discharged outlets (not shown) disposed in their respective helical tubular portions.
The embodiments described in this document provide non-limiting examples of possible implementations of the present technology. Upon review of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made to the embodiments described herein without departing from the scope of the present technology. For example, the systems and methods are described in relation to cooking grills but it is understood the systems and methods described herein are also applicable to other pellet-fired appliances such as outdoor heaters and fireplaces. Yet further modifications could be implemented by a person of ordinary skill in the art in view of the present disclosure, which modifications would be within the scope of the present technology.
Filing Document | Filing Date | Country | Kind |
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PCT/CA2020/051045 | 7/30/2020 | WO |