Electric grill

Abstract

An electric grill (10) includes a heating platform (20), a side wall (22), and a grill bar (14) spaced above the heating platform (20) together defining a heating chamber (16). The heating platform (20) is electrically heated. A first air supply (34) delivers pressurized air uniformly across the heating platform (20) from a central location. A second air supply (48) directs airflow along the side wall (22) to create an air vortex that flows around the first air supply (34). The forced airflow causes more complete combustion of grease and oil in food being cooked so that a grease tray is not needed.

Description

[0001] The present invention relates to an electric grill, also known as a charcoal grill, in which food is cooked while resting on heated grill rods.

[0002] A typical commercial electric charcoal grill utilizes electric heating elements housed within the grill rods on which food items rest. Grease and oil produced during cooking is directed into a grease tray which can also contain water to reduce the risk of a grease fire. Over time, the grease tray will fill with grease residue and this must be safely disposed of. However, grease fires remain a major problem and there is a general problem of improper disposal of grease residue, such as into a drain.

[0003] The present invention provides an electric grill comprising a heating platform, a plurality of side walls, a plurality of grill rods spaced above the heating platform, and a heating chamber defined between the heating platform, the side walls, and the grill rods, wherein the heating platform is electrically heated, the grill further comprising: a first air supply centrally positioned in the heating platform for delivering pressurized air into the heating chamber and configured to direct airflow across the heating platform, and a secondary air supply positioned in the side walls and configured to direct airflow along the side walls to create an air vortex that flows around the centrally positioned first air supply.

[0004] Preferably, the heating platform comprises two conductive plates with an electric heating element sandwiched between the two conductive plates. For example, a first plate can comprise an upper surface and a lower surface, and a plurality of grooves formed on the lower surface, and a second plate can comprise an upper surface and a lower surface, and a plurality of grooves formed on the upper surface, wherein the grooves in the first plate and the grooves in the second plate cooperate to form channels for receiving the heating element when the first plate and the second plate are sandwiched together.

[0005] The grill rods do not contain heating elements and are heated by radiation from the heating platform. Preferably, the heating platform is configured to reach temperatures of up to 500°C in order to heat the grill rods to temperatures of up to 350°C. For example, the heating platform can be formed of a metal or ceramic material.

[0006] The first air supply can comprise at least one opening in the heating platform connected to a source of pressurized air and an airflow diverter configured to divert the airflow uniformly across the surface of the heating platform. The airflow diverter can comprise an elongated post extending through the opening in the heating platform and a cap mounted on the upper end of the post. In particular, the airflow diverter can comprise a post having a plurality of radially projecting ribs.

[0007] The second air supply can comprise at least one opening in each side wall, the opening being positioned adjacent to the end of the side wall and connected to a source of pressurized air.

[0008] Preferably, the heating platform and the side walls are located within a housing having an inner wall and an outer wall and an air chamber located between the inner wall and the outer wall, wherein the air chamber is connected to a source of pressurized air and is in communication with the openings in the heating platform and the openings in the side walls. Typically, the source of pressurized air includes at least one fan.

[0009] In another embodiment, the heating platform and the side walls are located within a housing having an inner wall and an outer wall and a first air chamber located between the inner wall and the outer wall, wherein the air chamber is connected to a source of pressurized air and is in communication with the openings in the side walls of the heating chamber, and the electric grill further includes a second air chamber defined between the heating platform and the inner wall of the housing, wherein the source of pressurized air includes a fan configured to draw air from the second air chamber and supply the air to the first air chamber.

[0010] The application will now be described by way of example only, with reference to the accompanying drawings in which:

[0011] Figure 1 is a perspective view of an electric grill according to an embodiment of the application;

[0012] Figure 2a shows Figure 1 the grill with the grill bars removed to show the underlying heating chamber and heating platform;

[0013] Figure 2b is similar to Figure 2a but shows that the upper plate of the heating platform is also removed;

[0014] Figure 3 is a perspective cross-sectional view of the grill of Figure 1 from below, with some parts removed to show the underside of the heating platform;

[0015] Figure 4 is a perspective cross-sectional view of the device of Figure 2b from above, showing the air chamber;

[0016] Figure 5 shows a cross-section of the air guiding device;

[0017] Figure 6 is a top view of the air guiding device with the upper cap removed;

[0018] Figure 7 is a schematic plan view of the heating platform, illustrating the airflow;

[0019] Figure 8 is a partial cross-sectional side view of a second embodiment of the application.

[0020] Figure 1 A perspective view of an electric grill 10 according to one embodiment of the application is shown. This is illustrated as a freestanding unit, but grills incorporating the application can also be constructed as built-in units.

[0021] The grill 10 includes a body 12 made primarily of sheet metal. A grill grate 14 is disposed above a heating chamber, which is described further below. The body 12 can include a vertical back panel 18. Although not shown, a hinged lid can also be provided that can close over the top of the grill grate 14 to provide an enclosed cooking chamber. The grill grate 14 is typically made of cast iron and can withstand temperatures of up to about 250°C to 350°C.

[0022] Figure 2a and Figure 2b A portion of the grill 10 is shown in Figure 1 with the grill grate 14 removed to show the underlying heating chamber 16. The heating chamber 16 is defined between a heating platform 20, side walls 22 and the grill grate 14 (when present).

[0023] The heating platform 20 is electrically heated. Electrically powered heating elements can be located within the heating platform 20. For example, the heating platform 20 can include two metal plates 20a, 20b each having an upper surface and a lower surface. The lower surface of the upper plate 20a and the upper surface of the lower plate 20b are both machined with a plurality of grooves 24. When the plates 20a and 20b are clamped together, the grooves 24 in each plate align to define a channel in which a heating element is fitted. For example, the grooves 24 can be semi-circular in cross-section, such that when the plates 20a and 20b are clamped together, the grooves 24 align to define a channel having a circular cross-section. Figure 2a The upper plate 20a is shown in place, and Figure 2b The lower plate 20b is shown with the grooves 24, the upper plate 20a having been removed for illustrative purposes.

[0024] As mentioned above, both plates 20a, 20b can be formed of metal, for example steel, or another conductive material, for example a ceramic material such as silicon carbide. In this case, thermal insulation can be provided beneath the heating platform 20. Alternatively, the lower plate 20b can itself be formed of an insulating material.

[0025] In use, the heating platform 20 is heated by the heating element and acts as the primary heat source for cooking. The grill bar 14, which is located a small distance, for example 20cm to 70cm, above the heating platform 20, is heated primarily by radiant heat and some convection from the heating platform 20. The grill bar 14 therefore forms an auxiliary heat source for cooking, but does not contain a heating element itself. The heating platform 20 is typically heated to a temperature of up to about 500°C at which point a pyrolysis process occurs and this causes the grill bar 14 to reach a temperature of 250°C to 350°C. This primary heat source, provided by the heating element set inside the heating platform 20, is kept at a constant temperature and so any required variation of the auxiliary heat source can be achieved by adjusting the depth between the grill bar 14 and the heating platform 20 for different cooking styles.

[0026] Food items resting on the grill bar 14 are thoroughly cooked by the heat from the primary heat source, i.e. the heating platform 20. Direct contact of the food items with the auxiliary heat source, i.e. the grill bar 14, imparts a seared mark to the food items without fully burning them. The temperature reached by the grill bar 14 provides a suitable environment for the occurrence of the Maillard reaction which gives food a unique brown appearance and desirable taste.

[0027] The grill 10 of the present invention does not include a grease tray to collect excess grease and oil. Instead, the grill 10 further includes a forced air supply system to assist in the oxidation process of any grease and oil produced by the food, which would otherwise drip into the heating chamber 16 during cooking.

[0028] When grease and oil burns, the large carbon chain molecules associated with it require more oxygen to achieve complete combustion. In the absence of sufficient airflow, a black, carbon-rich flame with excess carbon monoxide is produced. However, in the present invention, the forced air supply causes cleaner combustion of the grease and oil and reduces the black, pungent smoke associated with partially combusted oil and grease. Pyrolysis is known to begin at around 500°C and, combined with oxidation in the well-oxygenated environment provided by the forced air supply of the present invention, this can assist in the oxidation of organic material into inorganic dust or ash. The grill 10 of the present invention therefore ensures complete combustion of any oil and grease, leaving only light ash residue which can be easily vacuumed away during regular cleaning. The grill 10 does not produce grease residue which can cause fire risk as well as health and environmental issues.

[0029] To provide the forced air supply system in the present application, a heating chamber 16 is provided within a double layer support structure 26 which includes first and second air supply portions which supply pressurised air into the heating chamber 16. The support structure 26 comprises an inner shell 28 and an outer shell 30 nested together with an air chamber 32 between the inner shell 28 and the outer shell 30. This can be seen in Figure 4 . The inner shell 28 has a centrally located opening 36. Below the opening 36 there can be an air inlet assembly 34 which comprises a perforated wall extending between the inner shell 28 and the outer shell 30 which defines a central air chamber below the opening 36. The structure of the air inlet assembly 34 can be similar to that described in GB2511850. A tube 46 extends upwards from the opening 36 to the underside of the heating platform 20. The heating platform 20 is also provided with a central opening 38 which is coaxial with the tube 46 and the opening 36 but of smaller diameter than the tube 46 and the opening 36. These features are best seen in Figure 5 .

[0030] Pressurised air is supplied into the chamber 32, for example by a fan 44 (which is shown only schematically in Figure 4 , but in practice this can be located within the body 12 of the grill 10, below the support structure 26).

[0031] The first (primary) air supply portion delivers pressurised air into the central region of the heating chamber 16. Pressurised air from the air chamber 32 enters the tube 46 via the air inlet assembly 34 and the opening 36 and then through the opening 38 in the heating platform 20 into the heating chamber 16.

[0032] An air directing device 40 is located in the opening 38 and projects upwards into the heating chamber 16 and downwards into the tube 46 towards the opening 36. The air directing device 40 comprises a central column with a plurality of radially projecting ribs. For example, there can be four projecting ribs so that its cross section is cruciform, as seen in Figure 3 and Figure 5 . As seen in Figure 4 , a circular cap 42 is located at the top end of the air directing device 40. The lower part of the air directing device 40 can be seen in Figure 3 , while the upper end portion without the cap is illustrated in Figure 6 . The air directing device 40 divides the opening 38 in the heating platform 20 into four quadrants. The cap 42 deflects the air flow upwards through the four quadrants and turns it laterally to flow out across the heating platform 20 into the heating chamber 16. This arrangement causes the air flow to be distributed quite evenly around the heating chamber 16.

[0033] The auxiliary air supply comprises a plurality of openings 48 in the side walls 22 of the heating chamber 16. Preferably, there is one or more openings 48 in each side wall, located at an end proximate to the corner where one side wall 22 meets the next. The openings 48 communicate with the air chamber 32 formed in the support structure 26, and so jets of pressurised air exit the openings 48 into the heating chamber 16. As the openings 48 are located towards the corners, this tends to create a vortex airflow that rotates around the heating chamber 16. This helps to pull the airflow outwards from the central primary air source to ensure good airflow throughout the heating chamber 16. Additionally, if any fat or oil droplets are combusting, the airflow will push these flames laterally rather than upwards. This can minimise the flames, and also prevents the food being cooked from burning.

[0034] Figure 7 is a schematic plan view of the heating platform 20, illustrating the airflow. The arrows P emanating from the central opening 38 represent the airflow extending in all directions from the first air supply. The arrows S, emanating proximate to the corners and extending along the edges, represent the airflow from the second air supply, which tends to rotate around the heating chamber 16, in this case in an anti-clockwise direction. The airflow from the central opening 38 initially spreads radially in all directions across the heating platform 22, but is gradually diverted by the airflow from the openings 48 so as to create an air vortex that flows around the opening 38.

[0035] The forced airflow provided by the first and second air supplies allows any fat and oil from the food items to combust more fully. Any flames that occur will burn cleaner and more quickly, and the production of smoke is reduced or eliminated. Any residue will form ash or dust, which can be removed from the heating chamber 16 by vacuuming. There is no fat residue or stagnant oil to deal with.

[0036] As mentioned above, the grill 10 of the present application does not comprise a fat tray to collect fat and oil that drips from the food being cooked. Instead, the heating chamber 16 beneath the grill bars 14 is an enclosed, controlled environment, in which the airflow is provided in a controlled manner via the first and second air supplies. Air can only exit the heating chamber 16 from the top, through the grill bars 14. This is in contrast to conventional grills, which require a fat tray to be placed beneath the grill bars, and so have a more open structure and are subject to external, uncontrolled air movement beneath the grill bars. In the present application, the enclosed heating chamber with controlled airflow provides the improved performance of the present application.

[0037] In this way, an improved electric grill is provided. The grill can quickly and efficiently cook food to preserve flavor and texture and minimize shrinkage. It can also achieve the desired searing characteristics without burning the food or creating unnecessary smoke and grease residue. The entire heating chamber is heated to a very high temperature, which causes animal fat and oil to vaporize, thereby minimizing residue and keeping food items moist.

[0038] Figure 8 An alternative embodiment of the electric grill 10 of the present application is shown. This differs from the above embodiment in certain features of the auxiliary air supply to the heating chamber 16, but other features of the grill 10 are the same as previously described.

[0039] In this case, the auxiliary air flow supplied to the openings 48 in the side walls 22 of the heating chamber 16 is drawn from a second air chamber 50, which is the space between the inner shell 28 and the underside of the heating platform 20. The air in this second air chamber 50 will be heated during use of the grill 10 and is drawn in via a duct 52 connecting the space 50 to the fan 54. The fan 54 then supplies this heated air into the air chamber 32 between the inner shell 28 and the outer shell 30 of the support structure 26. This heated air then flows into the heating chamber 16 via the openings 48 to create a vortex air flow that rotates around the heating chamber 16. Heated air can also be supplied to the air inlet assembly 34 and to the center of the heating platform 20 in the heating chamber 16. Alternatively, the primary air supply to the air inlet assembly 34 can be ambient air supplied by another fan.

[0040] Providing heated air from the second air chamber 50 as the auxiliary air flow further improves the efficiency of the grill 10. Using air from the second air chamber 50 avoids the creation of excessive heat buildup in this portion of the grill 10. In addition, supplying a flow of air that has already been heated into the heating chamber 16 maintains a higher temperature in the corners of the heating chamber 16. This in turn reduces the power requirements of the heating elements in the heating platform 20, such that lower wattage heating elements can be used to maintain equivalent temperatures in the heating chamber 16. As a result, the overall energy input required by the grill 10 is reduced, thereby maximizing the efficiency of the product.

Claims

1. An electric grill, comprising a heating platform, a plurality of side walls, a plurality of grill rods spaced apart above the heating platform, and a heating chamber defined between the heating platform, the side walls, and the grill rods, wherein, The heating platform is electrically heated, and the grill further includes a first air supply unit and an auxiliary air supply unit. The first air supply unit is centrally located in the heating platform for supplying pressurized air into the heating chamber and is configured to guide the airflow evenly across the heating platform. The auxiliary air supply unit is located in the side wall and is configured to guide the airflow along the side wall to generate an air vortex flowing around the centrally located first air supply unit.

2. The electric grill according to claim 1, wherein, The heating platform includes two conductive plates, with an electric heating element sandwiched between the two conductive plates.

3. The electric grill according to claim 2, wherein, The first plate includes an upper surface and a lower surface, and a plurality of grooves are formed on the lower surface. The second plate includes an upper surface and a lower surface, and a plurality of grooves are formed on the upper surface. The grooves in the first plate and the grooves in the second plate cooperate to form a channel for receiving a heating element when the first plate and the second plate are clamped together.

4. The electric grill according to any one of claims 1 to 3, wherein, The grill bar does not contain a heating element and is heated by radiation from the heating platform.

5. The electric grill according to claim 4, wherein, The heating platform is configured to reach temperatures up to 500°C in order to heat the grill bar to temperatures up to 350°C.

6. The electric grill according to any one of claims 1 to 3, wherein, The heating platform is formed of metal or ceramic materials.

7. The electric grill according to any one of claims 1 to 3, wherein, The first air supply unit includes at least one opening located in the heating platform connected to a pressurized air source and an airflow deflector configured to redirect airflow across the surface of the heating platform.

8. The electric grill according to claim 7, wherein, The airflow deflector includes an elongated column extending through an opening in the heating platform and a cap mounted on the upper end of the elongated column.

9. The electric grill according to claim 8, wherein, The airflow deflector includes a column with multiple radially projecting ribs.

10. The electric grill according to any one of claims 1 to 3, wherein, The auxiliary air supply unit includes at least one opening in each sidewall, the opening being located adjacent to an end of the sidewall and connected to a pressurized air source.

11. The electric grill according to any one of claims 1 to 3, wherein, The heating platform and the sidewall are located within a housing having an inner wall and an outer wall, and an air chamber located between the inner wall and the outer wall, wherein the air chamber is connected to a pressurized air source and communicates with an opening in the heating platform and an opening in the sidewall.

12. The electric grill according to claim 10, wherein, The pressurized air source includes at least one fan.

13. The electric grill according to claim 10, wherein, The heating platform and the sidewall are located within a housing having an inner wall and an outer wall, and a first air chamber located between the inner wall and the outer wall, wherein the air chamber is connected to a pressurized air source and communicates with an opening in the sidewall of the heating chamber, and the electric grill further includes a second air chamber defined between the heating platform and the inner wall of the housing, wherein the pressurized air source includes a fan configured to draw air from the second air chamber and supply air to the first air chamber.

14. The electric grill according to any one of claims 1 to 3, the electric grill further comprising a lid that can be closed over the grill bar to provide an enclosed cooking chamber.

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