Abstract:
The present invention relates to an induction hob with a number of induction coils ( 12 ) on a cooking surface ( 10 ) and an apparatus for determining the temperatures on the induction coils ( 12 ). The induction coils ( 12 ) are arranged on the cooking surface ( 10 ) according to a predetermined scheme. At least one temperature sensor ( 14, 16, 18, 20; 24, 26 ) is arranged within an intermediate space between two or more induction coils ( 12 ). The at least one temperature sensor ( 14, 16, 18, 20; 24, 26 ) and the central portions of at least two adjacent induction coils ( 12 ) are thermally connected by heat conductor elements ( 22 ). The temperature sensors ( 14, 16, 18, 20; 24, 26 ) are electrically connected to at least one evaluation circuit for determining the temperatures of the adjacent induction coils ( 12 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     THE NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT 
     Not Applicable 
     INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
     Not Applicable 
     BACKGROUND 
     Field of the Disclosure 
     The present invention relates to an induction hob with induction coils within a cooking surface and an apparatus for determining the temperatures on the induction coils. In particular, the induction hob is provided for household appliances. 
     Description of Related Art Including Information Disclosed Under 37 DFR 1.97 and 1.98 
     Induction hobs become an increasing meaning for cooking purposes, in particular for household appliances. The induction hobs comprise a number of induction coils arranged on a cooking surface. Each heating zone corresponds with one induction coil. In order to allow a control of the induction hob, several temperature sensors are provided on the cooking surface. Typically, a temperature sensor is arranged in the center of each induction coil. 
     Additionally, a piece of aluminum may be associated with the temperature sensor. Said piece of aluminum extends from the temperature sensor in the center of the induction coil to an outer position of the induction coil. The piece of aluminum acts as a heat conductor, so that the temperature at said outer position of the induction coil can be detected by the temperature sensor in the center of the induction coil. 
     A typical induction hob of the prior art requires a relative high number of temperature sensors, i.e. as the number of induction coils. 
     It is an object of the present invention to provide an induction hob with induction coils and an apparatus for determining the temperatures on the induction coils, which apparatus allows a reduced number of temperature sensors on said induction hob. 
     The object of the present invention is achieved by the induction hob according to claim  1 . 
     BRIEF SUMMARY 
     According to the present invention the induction hob is provided with a number of induction coils on a cooking surface and an apparatus for determining the temperatures on the induction coils, wherein: the induction coils are arranged on the cooking surface according to predetermined scheme, at least one temperature sensor is arranged within an intermediate space between two or more induction coils, the at least one temperature sensor and the central portions of at least two adjacent induction coils are thermally connected by heat conductor elements, and the temperature sensors are, in particular electrically or by remote, connected to at least one evaluation circuit for determining the temperatures of the adjacent induction coils. 
     The main idea of the present invention is the arrangement of the temperature sensors within the intermediate space between the induction coils on the one hand and the connection of the temperature sensors with the induction coils by the heat conductor elements on the other hand, wherein the one evaluation circuit is provided for determining the temperatures of the adjacent induction coils of said temperature sensors. This structure allows a reduction of the number of the temperature sensors. The number of the corresponding electronic detection circuits and wires is also reduced. 
     According to a preferred embodiment of the present invention at least a part of the induction coils is arranged as a matrix on the cooking surface or at least on a section of the cooking surface. 
     Alternatively or additionally, at least a part of the induction coils may be arranged as a honeycomb on the cooking surface or at least on a section of the cooking surface. 
     In particular, the at least one evaluation circuit may take into account the adjacent temperature sensors of the induction coil in order to determine the temperature of said induction coil. 
     For example, at least one temperature sensor is arranged within at least one intermediate space between three induction coils, wherein said induction coils form a triangle on the cooking surface. 
     Alternatively or additionally, at least one temperature sensor may be arranged within at least one intermediate space between four induction coils, wherein said induction coils form a rectangle or a square on the cooking surface. 
     Preferably, at least one heat conductor element is formed as an elongated sheet. This guarantees a sufficient heat transfer from the induction coil to the temperature sensor. 
     According to the preferred embodiment of the present invention at least one heat conductor element is triangular, wherein the most acute angle of said triangular heat conductor element is thermally connected to the central portion of the induction coil. 
     Further, at least one temperature sensor may be arranged in central portion of the induction coil. In this case the at least one temperature sensor may be connected to an adjacent intermediate space between two or more induction coils by a further heat conductor element. Thereby, at least one further heat conductor element is an elongated triangular sheet, wherein the most acute angle of said triangular heat conductor element is thermally connected to the intermediate space between two or more induction coils. 
     Preferably, at least one heat conductor element is made of metal, in particular made of aluminum. 
     Novel and inventive features of the present invention are set forth in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The present invention will be described in further detail with reference to the drawings, in which 
         FIG. 1  illustrates a schematic top view of an arrangement of nine induction coils within a cooking surface of an induction hob according to a first embodiment of the present invention, 
         FIG. 2  illustrates a schematic top view of an arrangement of eight induction coils within the cooking surface of the induction hob according to a second embodiment of the present invention, 
         FIG. 3  illustrates a schematic top view of an arrangement of ten induction coils within the cooking surface of the induction hob according to a third embodiment of the present invention, and 
         FIG. 4  illustrates a schematic top view of an arrangement of seven induction coils within the cooking surface of the induction hob according to a fourth embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a schematic top view of an arrangement of nine induction coils  12  within a cooking surface  10  of an induction hob according to a first embodiment of the present invention. 
     The nine induction coils  12  are arranged as a matrix with three lines and three columns. The nine induction coils  12  are denoted as C 1 , C 2 , C 3 , D 1 , D 2 , D 3 , E 1 , E 2  and E 3 . The numbers  1 ,  2  and  3  represent the lines of said matrix. The columns of said matrix are represented by the letters C, D and E. 
     Temperature sensors  14 ,  16 ,  18  and  20  are arranged in central positions of intermediate spaces between four induction coils  12  in each case. A first temperature sensor  14  is in the central position of the intermediate space between the induction coils C 1 , D 1 , C 2  and D 2 . A second temperature sensor  16  is in the central position of the intermediate space between the induction coils D 1 , E 1 , D 2  and E 2 . A third temperature sensor  18  is in the central position of the intermediate space between the induction coils C 2 , D 2 , C 3  and D 3 . A fourth temperature sensor  20  is in the central position of the intermediate space between the induction coils D 2 , E 2 , D 3  and E 3 . 
     From the temperature sensors  14 ,  16 ,  18  and  20  four heat conductor elements  22  in each case extend to the centers of the neighboring induction coils  12 . Four heat conductor elements  22  extend from the temperature sensor  14  to the centers of the induction coils C 1 , D 1 , C 2  and D 2 . In a similar way, four heat conductor elements  22  extend from the temperature sensor  16  to the centers of the induction coils D 1 , E 1 , D 2  and E 2 . Further, four heat conductor elements  22  extend from the temperature sensor  18  to the centers of the induction coils C 2 , D 2 , C 3  and D 3 . At last, four heat conductor elements  22  extend from the temperature sensor  20  to the centers of the induction coils D 2 , E 2 , D 3  and E 3 . 
     The heat conductor elements  22  are made of metal and formed as stripes. In this example, the heat conductor elements  22  are formed as elongated triangles, wherein the most acute angle of said triangle is arranged in the central portion the induction coils  12 . For example, the heat conductor elements  22  are made of aluminum. 
     The four neighboring induction coils  12  of the temperature sensor  14 ,  16 ,  18  or  20  form a square or at least a rectangle. 
     The temperature sensors  14 ,  16 ,  18  and  20 , the heat conductor elements  22  and evaluation circuit, which is not shown, form an apparatus for determining the temperatures on the induction coils. 
     The four temperature sensors  14 ,  16 ,  18  and  20  allow an approximate determination of the temperatures on each induction coil  12 . The following table illustrates the relationship between the temperature sensors  14 ,  16 ,  18  and  20  and the induction coils C 1 , C 2 , C 3 , D 1 , D 2 , D 3 , E 1 , E 2  and E 3 . 
     
       
         
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                   
               
               
                   
                 Temperature 
                   
               
               
                   
                 sensor 
               
             
          
           
               
                   
                 Induction coil 
                 14 
                 16 
                 18 
                 20 
               
               
                   
                   
               
               
                   
                 C1 
                 X 
                   
                   
                   
               
               
                   
                 C2 
                 X 
                 X 
               
               
                   
                 C3 
                   
                 X 
               
               
                   
                 D1 
                 X 
                   
                 X 
               
               
                   
                 D2 
                 X 
                 X 
                 X 
                 X 
               
               
                   
                 D3 
                   
                 X 
                   
                 X 
               
               
                   
                 E1 
                   
                   
                 X 
               
               
                   
                 E2 
                   
                   
                 X 
                 X 
               
               
                   
                 E3 
                   
                   
                   
                 X 
               
               
                   
                   
               
             
          
         
       
     
     If the temperature of the induction coil D 1  has to be determined, then the temperature sensors  14  and  16  are taken into account. However, the temperature sensors  14  and  16  will be affected by the temperatures of the adjacent induction coils  12 . The temperature sensor  14  will additionally be affected by the induction coils C 1 , C 2  and D 2 . In a similar way, the temperature sensor  16  will additionally be affected by the induction coils D 2 , E 1  and E 2 . However, the evaluation circuit always takes the worst case into account. 
       FIG. 2  illustrates a schematic top view of an arrangement of eight induction coils  12  within the cooking surface  10  of the induction hob according to a second embodiment of the present invention. 
     A first line and a third line include three induction coils  12  in each case. A second line includes two induction coils  12  arranged between intermediate spaces of the induction coils  12  of the first and third lines. Thus, the eight induction coils  12  of the second embodiment are arranged like a honeycomb. 
     The induction coils  12  of the first line are denoted as C 1 , D 1  and E 1 . The induction coils  12  of the second line are denoted as C 2  and D 2 . The induction coils  12  of the third line are denoted as C 3 , D 3  and E 3 . Thus, the numbers represent the lines and the letters represent substantially the columns. 
     In central positions of the intermediate spaces between three induction coils  12  in each case the temperature sensors  14 ,  16 ,  18  and  20  are arranged. A first temperature sensor  14  is in the central position of the intermediate space between the induction coils C 1 , D 1  and C 2 . A second temperature sensor  16  is in the central position of the intermediate space between the induction coils D 1 , E 1  and D 2 . A third temperature sensor  18  is in the central position of the intermediate space between the induction coils C 2 , C 3  and D 3 . A fourth temperature sensor  20  is in the central position of the intermediate space between the induction coils D 2 , D 3  and E 3 . 
     The three neighboring induction coils  12  of the temperature sensor  14 ,  16 ,  18  or  20  form a triangle. 
     From the temperature sensors  14 ,  16 ,  18  and  20  three heat conductor elements  22  in each case extend to the centers of the neighboring induction coils  12 . Three heat conductor elements  22  extend from the temperature sensor  14  to the centers of the induction coils C 1 , D 1 , C 2  and D 2 . In a similar way, three heat conductor elements  22  extend from the temperature sensor  16  to the centers of the induction coils D 1 , E 1  and D 2 . Further, three heat conductor elements  22  extend from the temperature sensor  18  to the centers of the induction coils C 2 , C 3  and D 3 . At last, three heat conductor elements  22  extend from the temperature sensor  20  to the centers of the induction coils D 2 , D 3  and E 3 . 
     The heat conductor elements  22  are of the same kind as in the first embodiment. The temperature sensors  14 ,  16 ,  18  and  20 , the heat conductor elements  22  and the evaluation circuit, which is not shown, form the apparatus for determining the temperatures on the induction coils. 
     In this embodiment four temperature sensors  14 ,  16 ,  18  and  20  are sufficient for determining the temperatures on the eight induction coils  12 . For example, in order to estimate the temperature on the induction coil D 1 , the evaluation circuit will take into account the temperature sensors  14  and  16 . 
       FIG. 3  illustrates a schematic top view of an arrangement of ten induction coils  12  within the cooking surface  10  of the induction hob according to a third embodiment of the present invention. 
     Two induction coils  12  are arranged in a first line, three induction coils  12  are arranged in a second line, also three induction coils  12  are arranged in a third line and again two induction coils  12  are arranged in a fourth line. The induction coils  12  of the second and the third line are arranged side-by-side. The induction coils  12  of the first line are arranged beside the intermediate spaces between the induction coils  12  of the second line. The induction coils  12  of the fourth line are arranged beside the intermediate spaces between the induction coils  12  of the third line. 
     Six temperature sensors  14 ,  16 ,  18 ,  20 ,  24  and  26  are arranged in the central positions of the intermediate spaces between three or four induction coils  12 , respectively. The first temperature sensor  14  is in the central position of the intermediate space between three induction coils  12  forming a triangle. In a similar way, the second temperature sensor  16  is in the central position of the intermediate space between three induction coils  12  forming a triangle. The third temperature sensor  18  and the fourth temperature sensor  20  are in the central positions of the intermediate spaces between four induction coils  12  in each case, wherein said four induction coils  12  form a square. A fifth temperature sensor  24  and a sixth temperature sensor  26  are in the central positions of the intermediate spaces between three induction coils in each case, wherein said three induction coils  12  form a triangle. 
     From the temperature sensors  14 ,  16 ,  24  and  26  three heat conductor elements  22  in each case extend to the centers of the three neighboring induction coils  12 , respectively. From the temperature sensors  18  and  20  four heat conductor elements  22  in each case extend to the centers of the four neighboring induction coils  12 , respectively. 
     The heat conductor elements  22  are of the same kind as in the first and second embodiments. The temperature sensors  14 ,  16 ,  18 ,  20 ,  24  and  26 , the heat conductor elements  22  and the evaluation circuit, which is not shown, form the apparatus for determining the temperatures on the induction coils. In this embodiment the six temperature sensors  14 ,  16 ,  18 ,  20 ,  24  and  26  are sufficient for determining the temperatures on the ten induction coils  12 . 
       FIG. 4  illustrates a schematic top view of an arrangement of seven induction coils  12  within the cooking surface  10  of the induction hob according to a fourth embodiment of the present invention. 
     Two induction coils  12  are arranged in a first line, three induction coils  12  are arranged in a second line and two induction coils  12  again are arranged in a third line. The induction coils  12  of the first line are arranged beside the intermediate spaces between the induction coils of the second line. In a similar way, the induction coils  12  of the third line are arranged beside the intermediate spaces between the induction coils  12  of the second line. Thus, there are six outer induction coils  12  and one central induction coil  12  on the cooking surface  10 . 
     The four temperature sensors  14 ,  16 ,  18  and  20  are arranged in the central positions of the intermediate spaces between three induction coils  12  in each case. A central temperature sensor  28  is arranged in the center of the central induction coil  12  of the cooking surface  10 . 
     From the temperature sensors  14 ,  16 ,  18  and  20  two heat conductor elements  22  in each case extend to the centers of the two neighboring outer induction coils  12 . From the central temperature sensor  28  one heat conductor element  22  extends to the intermediate space between the induction coils  12  of the first line and the central induction coil  12 . In the last case the most acute angle of the heat conductor element  22  is arranged within the intermediate space between the induction coils  12  of the first line and the central induction coil  12 . 
     Also these heat conductor elements  22  are of the same kind as in the above embodiments. The temperature sensors  14 ,  16 ,  18 ,  20  and  28 , the heat conductor elements  22  and the evaluation circuit, which is not shown, form the apparatus for determining the temperatures on the induction coils. In this embodiment the five temperature sensors  14 ,  16 ,  18 ,  20  and  28  are sufficient for determining the temperatures on the seven induction coils  12 . 
     There are many further constellations for the arrangement of the induction coils  12  and the temperature sensors  14 ,  16 ,  18 ,  20 ,  24 ,  26  and/or  28  according to the schemes of the above embodiments and/or combinations of said embodiments. The number of the induction coils  12  on the cooking surface  10  is not limited at the numbers of induction coils  12  in the above embodiments. 
     Although illustrative embodiments of the present invention have been described herein with reference to the accompanied drawings, it is to be understood that the present invention is not limited to those precise embodiments, and that various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit of the invention. All such changes and modifications are intended to be included within the scope of the invention as defined by the appended claims. 
     LIST OF REFERENCE NUMERALS 
     
         
         
           
               10  cooking surface 
               12  induction coil 
               14  first temperature sensor 
               16  second temperature sensor 
               18  third temperature sensor 
               20  fourth temperature sensor 
               22  heat conductor element 
               24  fifth temperature sensor 
               26  sixth temperature sensor 
               28  central temperature sensor 
             C 1  number of an induction coil 
             C 2  number of an induction coil 
             C 3  number of an induction coil 
             D 1  number of an induction coil 
             D 2  number of an induction coil 
             D 3  number of an induction coil 
             E 1  number of an induction coil 
             E 2  number of an induction coil 
             E 3  number of an induction coil