Patent Publication Number: US-10772465-B2

Title: Continuous cooking surface with individually controllable heating zones

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. application Ser. No. 15/365,487, filed Nov. 30, 2016, the entirety of which is hereby incorporated herein by reference. 
    
    
     BACKGROUND 
     A grill may include a continuous cooking surface heated by one or more heating elements positioned beneath the cooking surface. 
     SUMMARY 
     Examples are disclosed herein that relate to a grill with a continuous cooking surface having individually controllable heating zones. One example provides a grill, comprising a grill plate defining a continuous cooking surface comprising a plurality of individually controllable heating zones separated by one or more isolation zones, each heating zone comprising one or more heating elements positioned beneath the grill plate and each isolation zone comprising a cooling fluid channel, and the grill also comprising a cooling fluid circulation system configured to control a flow of a cooling fluid through the cooling fluid channel for each isolation zone. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a top view of an example grill comprising a continuous cooking surface with individually controllable heating zones separated by isolation zones. 
         FIG. 2  shows a perspective view of the continuous cooking surface of the grill of  FIG. 1 . 
         FIG. 3  shows a side view of the continuous cooking surface of the grill of  FIG. 1 . 
         FIG. 4  shows a bottom perspective view of the continuous cooking surface of the grill of  FIG. 1 . 
         FIG. 5  shows a sectional view of the continuous cooking surface of the grill of  FIG. 1 . 
         FIG. 6  shows a schematic diagram of an example cooling system for cooling an isolation bar. 
         FIG. 7  shows an example edge configuration for a continuous cooking surface. 
         FIG. 8  shows an example heater compression plate assembly. 
         FIG. 9-10  schematically show an example continuous cooking surface having isolation zones comprising channels formed in a grill plate. 
         FIGS. 11-14  schematically show views of a grill plate having a cooling channel and cover. 
         FIGS. 15-17  schematically show a continuous cooking surface having a cooling channel bored into a grill plate. 
         FIG. 18  shows a schematic diagram of an example cooling fluid circulation system configured to form two isolation zones on a grill plate. 
         FIG. 19  shows a top view of the grill plate of  FIG. 18  and schematically illustrates example locations for cooling fluid channels. 
     
    
    
     DETAILED DESCRIPTION 
     As mentioned above, a grill may include a continuous cooking surface with one or more heating elements positioned beneath the cooking surface to heat the cooking surface. In some situations, it may be desirable to cook foods at different temperatures on the same cooking surface. For example, a person may wish to reduce a sauce or soup in a pot or pan at a higher temperature, then simmer the sauce or soup at a lower temperature. When using a grill with a single temperature control, the person may first place the pot or pan closer to an outside edge of the grill, and then move the pot or pan to the middle, as heating element positioning and heat transfer characteristics may cause the cooking surface temperature to decrease toward the outside edge. As another example, a person may wish to simultaneously cook meats and vegetables on the same grill at different temperatures, and thus the person may cook vegetables closer to the outside edge of the grill while cooking meats closer to the middle. However, the temperature in the cooler region may not be easily controllable or measurable in such an arrangement. 
     Some grills may include individually controllable heating elements for different heating zones of the continuous cooking surface, which may provide more control over the temperatures of different regions of the continuous cooking surface. However, as the materials from which the cooking surfaces are made are good thermal conductors, it may be difficult to maintain the temperatures of different heating zones at desired levels, particularly with large temperature differentials, due to the transfer of heat between regions. 
     Accordingly, examples are disclosed herein that relate to a cooking system having a continuous cooking surface comprising heating zones that may be more easily maintained at different temperatures. The individual heating zones of the continuous cooking surface are separated by one or more isolation zones incorporated into the continuous cooking surface. Such isolation zones may include cooling features to facilitate air or fluid-assisted cooling, thereby helping to lessen the conduction of heat between adjacent heating zones. Further, as the cooking surface is continuous, food may be easily moved between cooking surface by sliding the food from one heating zone to another. 
       FIG. 1  schematically shows a top view of an example cooking system  100  having a continuous cooking surface  102  segmented into three heating zones  102 ,  104 , and  106  by isolation zones  108  and  110 . Heating zones  102 ,  104  and  106  have individually controllable heating elements, such that each heating zone can be set at a different temperature relative to adjacent heating zones, whether higher or lower. While heating zones and two isolation zones are shown, a cooking system may have any other suitable number of heating zones and cooling zones.  FIG. 1  also illustrates a flange  112  surrounding the cooking surface, e.g. to help contain food from spilling over an edge of the cooking surface  102 . 
       FIG. 2  shows a perspective view of the cooking surface  102 . The isolation zones  108  and  110  take the form of isolation bars joined to adjacent heating plates of adjacent heating zones, such that upper surfaces of the isolation bars and heating plates form the continuous cooking surface. 
       FIG. 3  shows a side view of the cooking surface  102 . As depicted, the upper surfaces of isolation bars  110  and  112  are level with the upper surfaces of heating zones  104 ,  106 , and  108  to form a level, continuous surface across which food and/or cookware can be easily moved. The heating zones  104 ,  106  and  108  and the isolation bars  110 ,  112  may be formed from any suitable material(s). In some examples, the heating zones  104 ,  106 , and  108  comprise thermally conductive plates formed from steel. The thermally conductive plates may have any suitable thickness, including but not limited to thicknesses between 0.5 and 1 inch. The isolation bars  110 ,  112  may be formed from a same material as the heating zone plates, or from a different material than adjacent heating zone plates, such as a material having a lower thermal conductivity than the heating zone plates. 
       FIG. 4  shows a bottom view of the cooking surface  102 , and illustrates an example arrangement of heating elements  400  for each heating zone. In the depicted example, the cooking system comprises three heating elements for each heating zone, for a total of nine heating elements  400   a - i . The heating elements may utilize any suitable heating mechanism. For example, the depicted heating elements may comprise resistive heating elements formed from an etched resistive foil located between insulating layers. In other examples, any other suitable number, size, and arrangement of heating elements of any suitable shape/size/heating mechanism may be used. 
     In the depicted example, each heating element  400  includes a hole  401  to accommodate a temperature sensor (e.g. a thermocouple) for monitoring temperature of the heating plate above the heating element. In other examples, any other suitable arrangement of temperature sensors may be used such as fewer temperature sensors than heating elements per heating zone, or more than one temperature sensor per heating element. In the depicted example, each heating element further includes six holes to accommodate fasteners for fastening the heating element to a cooking surface. In other examples, any other arrangement of and/or type of attachment points for fasteners may be used. Another example arrangement in which only a single attachment point is utilized to fasten each heating element to the cooking surface is described below with regard to  FIG. 8 . 
     Signals from each of the temperature sensors may be sent to a temperature controller to allow independent control of each heating element based on the sensed temperatures. For example, the controller may be configured to automatically provide more or less power to one or more heating elements underneath a heating zone to maintain the temperature of that heating zone at a set temperature. 
     Each isolation bar  110 ,  112  may be secured to adjacent conductive plates in any suitable manner.  FIGS. 4 and 5  show one example in the form of bolts, two of which are indicated at  402  and  404 . In other examples, other suitable fasteners may be used. Referring to  FIG. 5 , each bolt is angled with respect to a plane of the cooking surface  102 . This arrangement may help to provide for a suitably tight connection of each isolation bar to adjacent conductive plates. In other examples, any other suitable fasteners may be utilized to join each isolation bar to adjacent conductive plates. 
     Each isolation bar may have any suitable structure that helps lessen heat transfer between heating zones. In the depicted embodiment, each isolation bar includes a cooling channel that takes the form of a recess in an underside of the isolation bar that extends at least partially along a length of the isolation bar. In other examples, the cooling channel may take the form of a bore formed at least partially through a length of the isolation bar, as opposed to a recess in an underside of the isolation bar. In the depicted example, each cooling channel accommodates a cooling fluid conduit, such as a tube  406  and  408  for each of isolation bars  110  and  112 , respectively.  FIG. 5  shows a closer, detailed cutaway view of the isolation bar  110  including cooling channel  500  in which conduit  406  is positioned. Though shown herein as a U-shaped channel, a cooling channel may take any other suitable shape and may be formed along any suitable length of each isolation bar. Further, in other examples, the cooling channel may facilitate air cooling by increasing a surface area of the cooling channel in contact with ambient air or a flow of air from a fan or other blower, as opposed to accommodating a cooling fluid conduit. In other examples, cooling channels may be formed along the top sides or lateral sides of the isolation bars, rather than in the undersides or as a borehole through an interior region. In yet other examples, one or more isolation bars may not include cooling channels, and may instead rely on different thermal conductivities of each heating zone plate to provide suitable thermal isolation. 
     Where a cooling fluid is used as a part of a cooling system for the isolation bars of a cooling surface, the cooling system further may include a pump configured to move a cooling fluid through the cooling fluid conduit in each isolation bar.  FIG. 6  schematically shows an example pump  600  that moves a cooling fluid through the conduit  602  of an isolation bar  604 . Any suitable cooling fluid may be pumped through the isolation bars, including but not limited to water and glycol-based coolants, a compressed refrigerant, or air. An air-cooled radiator  606  may help to cool the coolant after the coolant travels through the isolation bar  604 . In other examples, any other suitable cooling techniques may be utilized. 
     In some examples, the cooking surface may be suspended above a supporting base structure, e.g. a body  712  or other structure, where a portion of the cooking surface perimeter extends beyond the base structure. Further, the perimeter of the cooking surface extending beyond this base structure may include elements that help to prevent oil and other liquids from dripping down an edge of the cooking surface and migrating to an underside of the cooking surface. FIG.  7  shows a side view of an example configuration of an edge  700  of the cooking surface  102 , illustrating the top surface at  702 , the underside  704 , and an outside edge  706 . The outside edge  706  may be straight or may be angled to any suitable degree, either outward as shown, or inward in other examples. The edge  700  also includes a drip edge  708  that extends between the bottom of the outside edge  706  and a drip channel  710 . The drip channel  710  may be formed in the underside  704  in an angled shape, as shown, or in any other suitable shape (e.g. circular), nearby the outside edge  706 . Such a drip channel may be formed along each outside edge of the cooking surface  102 . Oils and liquids from the top surface  702  that fall down the outside edge  706  may follow the drip edge  708  to the drip channel  710 . The drip channel  710  may cause such oils and liquids to pool and fall down vertically from the channel, and thus help to prevent further movement of oils and liquids along the underside  704  toward a body of the grill, represented by dashed line  712 , which may be damaging to electrical heating elements and other components that may be attached to the underside  704  of the cooking surface  102 , or electrical components  714  on or within the body  712 . 
     In additional examples, the grill may include a control panel  716  to allow control of various functions of the grill, such as the control of the temperature of the cooking surface, either as a whole or separately for each heating zone. User input may control the power supplied by a solid state relay for each heating element of a heating zone. The control panel  716  may further be configured to provide visual feedback, for example, to show a current temperature of each heating zone, as measured by the installed thermocouples. As an example, dynamic offsets may be utilized between each heating zone to calculate the actual surface temperature from the temperature as measured by the thermocouples, as the thermocouple measurements of the underside of the cooking surface may differ from actual surface temperatures. The control panel  716  may utilize any suitable user input devices, including but not limited to buttons, knobs, and one or more touch sensitive displays. Likewise, the control panel  716  may include any suitable display devices, including but not limited to light-emitting diodes, liquid crystal displays, and organic light emitting devices. 
       FIG. 8  shows an example heater compression plate assembly  800  having a cassette  802  for securing a heating element  804  and an insulating refractory brick  806  against the underside of the cooking surface  102 . In this example, the heating element  804  may be attached to the cooking surface  102  at a single location. Such a compression method may allow for the more convenient attachment of the heating element  804  to the underside of the cooking surface  102  than other methods (e.g. welding) and may help to increase the watt density and efficiency of the heating element  804 . The cassette  802  may be reinforced with longitudinal support structures  808  extending from a middle portion of the cassette  802  to the outer corners. Other distributed compression support structures also may be used, such as a suitably shaped washer  810 . The cassette  802  may be secured and compressed to an underside of the cooking surface  102  by a threaded collar  812 , washer  814 , and nut  816 , or by any other suitable attachment mechanism. A thermocouple may be inserted through the threaded collar  812 , and into the underside of the cooking surface  102  to sense a temperature of the cooking surface  102  at that location, as mentioned above. 
     In the above examples, the isolation zones take the form of isolation bars joined to adjacent heating plates. In other examples, an isolation zone may comprise a cooling channel formed in a grill plate to accommodate a flow of cooling fluid to remove heat from the isolation zone, thereby helping to reduce heat transfer between adjacent heating zones. In some such examples, the cooling fluid channels comprise conduits located within the channels to conduct the cooling fluid, while in other examples the cooling fluid flows directly in the channels, without a separate conduit. 
       FIGS. 9-10  schematically show an example grill plate  900  having a continuous cooking surface and including isolation zones  902 ,  904  each comprising cooling fluid channels  906 ,  908  formed in an underside of the grill plate. The channels of  FIG. 9  have a curved path which define a 2×2 grid of heating zones  910 , thereby providing for four heating zones via the use of two channels.  FIG. 10  shows a cross-sectional view of the grill plate  900 . Cooling fluid may flow directly through the channels  906 ,  908  (e.g. by covering the channels with an appropriate sealing structure), or conduits may be placed in the channels for conducting a cooling fluid through the channels  906 ,  908 . 
     In the example of  FIGS. 9-10 , the channels have a curved configuration to define the 2×2 layout of heating zones.  FIGS. 11-14  show another example in which a grill plate  1100  has a channel  1102  with a straight configuration. Further, a cover  1104  is attached to the grill plate  1100  to cover the cooling fluid channel  1102 , thereby defining a path for coolant flow without the use of a separate conduit within the channel  1102 . The cover  1104  may be fastened to the grill plate  1100  in any suitable manner, such as via bolts  1106  or other suitable fasteners, and seals  1108  may be disposed in between the cover  1104  and the grill plate  1100 .  FIG. 13  shows a horizontal cross-sectional view of  FIG. 11 , and  FIG. 14  shows a vertical cross-sectional view of  FIG. 11 , illustrating the resulting flow pathway and connection of the grill plate  1100  to the cover  1004 . 
       FIG. 15  schematically shows a grill plate  1500  having a cooling channel  1502  directly bored into the grill plate  1500 , instead of being formed (e.g. by casting or milling) into an underside of the grill plate.  FIG. 16  shows a horizontal cross-sectional view of  FIG. 15 , while  FIG. 17  shows a vertical cross-sectional view of  FIG. 15 . The configuration of  FIGS. 15-17  also eliminates the need to insert a separate coolant conduit. 
     In any of the above examples, a grill may include a cooling fluid circulation system to control a flow of a cooling fluid throughout the cooling fluid channel of each isolation zone. The cooling fluid circulation system may include one or more pumps and one or more radiators to remove heat transferred from the grill plate by the cooling fluid. In various examples, each of the one or more radiators may be passively cooled via exposure to ambient air, or may be actively cooled, e.g. by a fan configured to direct a flow of air onto the radiator. In some examples, each isolation zone may have its own cooling fluid circulation system, while in other examples a common pump may deliver cooling fluid to multiple isolation zones via a common manifold.  FIG. 18  shows a schematic diagram of an example cooling fluid circulation system  1800  having a dual conduit configuration, showing a manifold  1805  leading to conduits  1802 ,  1804  positioned in the grill plate  1206 . The outflow of conduits  1802 ,  1804  connect to a return manifold  1807 , which leads to a radiator  1808  cooled by a fan  1809  attached to the back of the radiator  1808 . The cooling fluid circulation system further comprises a pump  1810  configured to circulate the cooling fluid.  FIG. 19  shows a top view of the example grill plate  1806 , and illustrates channels  1902  and  1904  formed in an underside of the grill plate  1806  in such a configuration as to define two isolation zones and three heating zones. 
     It will be understood that the configurations and/or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be considered in a limiting sense, because numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. As such, various acts illustrated and/or described may be performed in the sequence illustrated and/or described, in other sequences, in parallel, or omitted. Likewise, the order of the above-described processes may be changed. 
     The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various processes, systems and configurations, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof.