Abstract:
A controller provides adjustable power levels to heat a cooking device. A power flow controller can be used to adjust levels of power received from a power source.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     The present application is based on and claims the benefit of U.S. provisional patent application Ser. No. 60/733,028, filed Nov. 3, 2005, the content of which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND  
       [0002]     Current electric frying pans do not easily or satisfactorily allow one to slow cook food, such as meat, without having the heating element of the electric frying pan getting overly hot. A typical thermostat control of a frying pan merely switches the heating element from full on to off, with the control being an average temperature. For example, if one wants to cook meat in the electric frying pan, the user will typically sear the meat first. After searing the meat in the pan, if one wants to slow cook, the user adjusts the temperature of the electric frying pan to a lower temperature such as 200° F. However, in order to maintain the average temperature of 200° F., the heating element in the bottom of the electric frying pan will be turned fully on, thereby obtaining an extremely hot temperature until the overall temperature comes to 200° F. Nevertheless, the extremely hot temperatures will cause some burning off of the meat juices, gravy and similar liquids during the time when the heater is on.  
       SUMMARY  
       [0003]     A controller provides adjustable power levels to heat a cooking device. By providing adjustable power levels, the controller can maintain a temperature of the cooking device close to a desired temperature set by a user. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0004]      FIG. 1  is a schematic view of an environment for controlling temperature of an electric frying pan.  
         [0005]      FIG. 2  is a schematic view of an environment for controlling temperature of an electric frying pan.  
         [0006]      FIG. 3  is a flow diagram of operation of a controller for controlling temperature of an electric frying pan. 
     
    
     DETAILED DESCRIPTION  
       [0007]      FIG. 1  illustrates a controller  8  that provides uniform temperatures for electric frying pans for purpose of slow cooking. In particular, the temperature of the frying pan can be selected. In the embodiment illustrated, the controller  8  can comprise a power flow controller such as an AC speed controller, for example, used for AC power tools such as drills and routers. The controller  8  is connectable to a source of AC power such as 110 volts, which is represented at source  10 . The controller  8  includes a selection switch  14 , which can be set to a “constant” output setting, namely 110 volts output, or a “variable” output setting, which would allow power to flow through a power flow controller  16 . Any suitable device can be used to control the power, for example a rheostat, variable voltage transformer or triac circuit such as used in speed control of drills and routers. The power flow controller  16  controls the power to a heating element  18  of a frying pan  20 . With the adjustable (i.e., lower) voltage provided to the heating element  18 , the heating element can maintain a uniform temperature that is lower than the high temperature that would be obtained if it were otherwise connected directly to 110 volts AC.  
         [0008]     In the embodiment illustrated, frying pan  20  can be of a conventional design having a temperature controller shown as thermostat  22 , with an adjustable knob  24  correlated to desired temperatures. A light  28  typically is provided to indicate when power is being provided to the heating element  18 . A power cord  26  of the electric frying pan  20  is connected to the controller  8  typically via a female electrical receptacle. When a temperature of frying pan  20  is less than the temperature indicated by knob  24 , power is supplied to heating element  18 . If the temperature of frying pan  20  is above the temperature indicated by thermostat  22 , power is not drawn by heating element  18 . It should be noted that controller  8  could be integrated into a single element with thermostat  22 , if desired.  
         [0009]     Use of controller  8  with electrical frying pan  20  to cook meat can be as follows. Initially, switch  14  is adjusted to the “constant” setting so that full 110 volts is provided to heating element  18  of the electric frying pan  20 . Using the temperature adjustment capabilities of the electric frying pan  20 , one can set thermostat  22 , for example, at 400° F. to brown or sear the meat. Then, in order to provide slow cooking of the meat, the knob  24  is adjusted to a lower setting, such as 200° F., at the controller  22  and the pan is allowed to cool down to 200° F. Using the knob  24 , it can be determined in conjunction with the light  28  coming on as to operation of the heating element  18  with regard to the desired temperature of the electric frying pan  20 . When the lowered desired temperature has been obtained, the knob  24  is maintained at the desired, temperature and the switch  14  is operated to the “variable” setting. Power flow controller  16  is then adjusted so as to cause light  28  to flicker, which indicates that the heating element is receiving enough power at a reduced voltage in accordance with the controller  8 , but sufficient to maintain the electric frying pan  20  at the desired temperature  
         [0010]      FIG. 2  illustrates another embodiment of a controller  30 , similar in purpose to controller  8  described above. Like controller  8 , controller  30  includes a connector  26  suitable for obtaining power from the electrical source  10  and an output receptacle through which heating element  18  of electric frying pan  20  can be connected. Controller  30  allows for automatic adjustment of electrical power provided to the electric frying pan  20  in order to maintain the desired temperature. Thus, the need for a user controlled power flow controller described with respect to  FIG. 1  is obviated.  
         [0011]     Controller  30  includes a power flow controller  36  (such as a triac), a power flow sensor  38  (such as a current or voltage sensor) and a timer  40 . Processing circuitry  42  controls operation of the power flow controller  36 . Processing circuitry  42  can include a counter coupled to a decoder to select a particular relay or a combination of relays. Each relay can include a resistor to provide a desired control signal to power flow controller  36 . As in the previous embodiment, the user adjusts knob  24  to obtain a desired temperature. Additionally, it should be noted that controller  30  can be formed as a single unit with thermostat  22 .  
         [0012]      FIG. 3  is a flow diagram of operation of controller  30 . Generally, the flow diagram illustrates a controlled loop  50  for increasing power (i.e. voltage) to the frying pan and a second control loop  52  for decreasing the power to the electric frying pan. The sensor  38  and timer  40  are used to control operation between the control loops  50  and  52  in order to automatically obtain the necessary power to maintain the desired temperature of the pan  20 .  
         [0013]     Assuming initially a starting point of providing full power is capability to the electric frying pan, as indicated at step  54 , controller  30  then initiates the timer at step  56 . At step  58 , it is determined whether or not the electric frying pan is drawing any power as measured by the sensor  38  at step  58 . If the electric frying pan is not drawing any power it is apparent that full power is not needed in order to maintain a desired temperature and the temperature is reduced at step  60 . The power can be reduced by a suitable interval, for example by 5 or 10 percent. This new power setting is maintained until the electric frying pan actually draws power as indicated at step  62  where upon flow returns back to step  56  and the timer is again started.  
         [0014]     Assuming now that the electric frying pan is drawing power at step  58 , flow continues to step  64  where upon the timer is checked to see if it has timed out. If the timer has not timed out, flow continues back to step  58  in order to determine if this electric frying pan is still drawing power. This loop is continued until the timer has timed out indicating that the electric frying pan requires more power in order to obtain a desired temperature. Accordingly, flow continues to step  66  where the power is increased and the timer is again restarted at step  56 . By using control loops  50  and  52 , the necessary power to obtain the desired temperature can be ascertained within a range.  
         [0015]     Although the concepts provided herein have been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the claimed subject matter.