Abstract:
A cookware article for use on an electronically controllable heat source, such as an induction stovetop, has a tight fitting lid that include a whistle that is activated by the steam pressure when water boils. The electronically controllable heat source is operative to reduce the power in response to the whistle so that the water temperature is lowered to a power setting for simmering or the appropriate cooking method after the water boils.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of priority to the PCT application No. PCT/2013/027372, which was filed on 22 Feb. 2013, and which in turn claims the benefit of priority to the US patent application of the same title that was filed on 24 Feb. 2012, having application Ser. No. 61/602,961, and are both incorporated herein by reference. 
     
    
     BACKGROUND OF INVENTION 
       [0002]    The present invention relates to an improved method of cooking, and in particular to cookware heating source that are responsive to the cookware. 
         [0003]    Prior methods of cooking deploy thermocouples or thermometers to measure either the temperature of the vessel, or the foodstuff therein to cook at a fixed temperature. 
         [0004]    In some types of food preparation, it is desirable that the water be heated to a boil before the temperature is lowered. The detection of boiling, from a cooking perspective, is not simply the issue of water reaching the boiling temperature, but that the pot or vessel has received sufficient energy such that the quantity of steam bubbles produced in the water provides violent agitation, which is generally referred to as a rolling boil. 
         [0005]    In addition, it is frequently desirable to reduce the heat applied after a rolling boil is obtained to simmer the foodstuffs in the pot, or after subsequent cooling from the addition of cool ingredients, to then return the contents to a boil. 
         [0006]    Whistles are traditionally used to determine when water in a teapot has boiled. Whistles have also been deployed in the lids of cookware. Pressure cookers in fact produce an audible sound, not unlike a whistle, when steam escapes to control pressure. 
         [0007]    Cook&#39;s frequently waste time waiting for water to boil in open vessel or pots, when they could be more productive using there time on other tasks, and are frequently need to interrupt these other tasks to check and see if indeed the water has boiled. This is fairly important in cooking rice and some noodles and pasta for example; as the temperature should be lowered after a boil is reached with the ingredients in the vessel. 
         [0008]    It is therefore a first object of the present invention to provide a cooking device that provides the above benefits to the user. 
         [0009]    Having a means for automated detection of water boiling in a cooking vessel, and the subsequent automated control of the cooking temperature would provide several advantages to cooks, such as the faster and improved preparation of pasta, rice as well as making it easier for a cook to multi-task in the kitchen. 
       SUMMARY OF INVENTION 
       [0010]    In the present invention, the first object is achieved by a cooking system comprising a heat source powered via a controller, a cookware vessel having a tight fitting lid and a steam activated whistle in the lid, wherein the controller is operative to modulate the power to the heat source in response to the noise generated by the steam activated whistle. 
         [0011]    A second aspect of the invention is characterized by an induction cooking system comprising an induction burner base having at least one coil powered via a controller, a cookware vessel having a tight fitting lid and a steam activated whistle in the lid wherein the controller is operative to modulate the power to the induction burner in response to the noise generated by the steam activated whistle. 
         [0012]    The above and other objects, effects, features, and advantages of the present invention will become more apparent from the following description of the embodiments thereof taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0013]      FIG. 1  is a cross-sectional elevation of a preferred cookware vessel for use with the heater shown in  FIG. 2 . 
           [0014]      FIG. 2  is a block functional diagram of a heater that is operative in response to the direct input of the user as well as feedback from the cookware vessel. 
           [0015]      FIGS. 3A and 3B  are cross-sectional elevation of the whistle in  FIG. 1 , in which  FIG. 3B  is enlarged to show detail of the whistle construction. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Referring to  FIGS. 1 through 3 , wherein like reference numerals refer to like components in the various views, there is illustrated therein a new and improved Cookware with heat source with audible feedback control, the heat source being generally denominated  100  herein. 
         [0017]    In accordance with the present invention, as illustrated in  FIG. 1 , there is a heat source  100  that support and provides energy to cookware vessel  10 . The cookware vessel  10  is covered by a tight fitting lid  11 , which forms a substantially vapor tight seal with the rim  12  of vessel  10  at its&#39; own rim  13 . The lid  11  has a handle  15  and a whistle  16  that is steam activated. The steam  2  is generated by the boiling of water  1  in vessel  10 , caused by heating element  150  of heat source  100 . As further described below, the heat source  100  has a sound detection means that is operative to reduce power in response to “hearing” a whistle. Heat source  100  also preferably has an external control panel  150 . 
         [0018]    The whistle  16  has a constricted exit orifice through which steam  2  escapes to the volume external to the vessel  10  and lid  11  (shown as  2 ′) wherein this flow of steam produces detectable sound. The sound quality is partly determined by deploying a cavity before the exit orifice, where the entrance of steam to this cavity is a first or entrance orifice. 
         [0019]      FIGS. 3A and 3B  are cross-sectional elevations of such a whistle  316 . Cavity  301  and cavity  302  are defined by concentric threaded fitting  310 ,  320  and  330 , with the outer orifice  340   a  from outer cavity  302  direct to point sideways by a cap  340  that engages the upper concentric fitting  330 . The upper  330  and mid  320  concentric fittings engage to seal the penetration in the lid wall, whereas the lower concentric fitting provides the first or inner orifice  310   a  for steam to enter cavities  301  and  302 . Optionally, a spring  350  can be used to support cap  340  upward to open orifice  340   a,  or the cap  340  can be rotated and locked into a lower portion of the mid concentric fitting  330  to close the outer orifice  340   a.  A mid orifice  320   b  is disposed above the lower cavity  301 , being provided within the center of the mid concentric fitting. The mid orifice  320   b  is narrow than the outer orifice  340   a,  which hence along with orifice  310   a  and lower cavity  301  primarily defines the whistle sound characteristic. 
         [0020]    Ideally the sound is also at a frequency and volume to be audible, but more significantly is readily discerned from kitchen background noises, such as speech, noise form fans and the motors of other electronic appliances, and the like. 
         [0021]    Among the various benefits of the invention that particularly accrue when the heating source is an induction burner is the faster preparation of pasta, as water in the vessel will come to a boil very quickly at full power, due to the high efficiency of induction heating of the cookware, even before pasta is added. Traditionally, the pasta is only added after the water in the pot comes to a rolling boil. However, as the cool pasta usually causes the water to cease boiling, depending on the quantity of pasta to cease, a cook waits for the water to return to a second boil, before turning the power down so that the water simmers. Salt and oil are added by some cooks either before or after adding the pasta. 
         [0022]    The quality and consistency of the cooked pasta can be improved, if the temperature can be reduced as soon as the water returns to a boil, and the total heating time can be tracked to avoid overcooked. This is particularly critical for ravioli or other stuffed or filled pasta, which can explode if the water is boiling to vigorously for an excessive amount of time. Hence, automated detective of a first and second boil can provide a more productive use of the cook&#39;s time than watching or waiting for water to boil or return to a boil and then having to reduce the heat to the cookware so the pasta or other food only simmers. Further, the automated control of power to the cooking vessel as described herein also makes it easier for a cook to multi-task in the kitchen. 
         [0023]    More specifically, the means for electronically controlling the heat source  100  via whistle sound detection and subsequent power reduction first require the detection of the whistling sound based on an audible sensor detecting a noise meeting a threshold criterion of at least one of volume and frequency. Therefore a sound transducer  110 , which can be a microphone, is deployed to pick up the sound to transform it into electrical signals for further processing, such as by a microprocessor device, or general purpose computing device that is programming or the specific purposes disclosed herein. A preamplifier and/or amplifier stage  120  with automatic gain control (AGC) is preferably deployed to pre-condition the signal to suitable level for recognition purposes. 
         [0024]    Tone decoders  130  (such as an array of band pass filters) can then be used to categorize the sound detected into narrow frequency bands for comparison against known whistle sound pattern. Then a controller/microprocessor  140  is deployed to analyze the duration and/or frequency purity to discriminate the whistle sound against human speech, music, as well as other background noise that may be present in the environment, and may optionally determine and adjust for sampling errors and the like. The controller/microprocessor  140  may then optionally adjust the output power of the burner downward to confirm the whistle sound characteristics detected if required. 
         [0025]    Another aspect of the invention is that the heater  100 , such as an induction burner, has operating modes accessed by the same or a different controller/microprocessor  140  for cooking specific foods or cooking modes, in which operating/cooking modes can selected by the control panel  150 . 
         [0026]    An induction burner is a preferred heat element  100 , that more preferably also includes at least one of IR sensors or thermocouples to also monitor the temperature of the cooking vessel  10  or the contents therein, and causes rather rapid and immediate change to the heat delivered to the cooking vessel  10 . 
         [0027]    It should be appreciated that the controller/microprocessor  140  is preferably programmed to differentiate the sound of the whistle sound from background noise, and that such programming may include also considering as background noise, all sounds that occur before the water could possibly reach the boiling point, such as when the temperature as measured by IR or other means is well below the boiling point, as well as a conditioning time between activating the heat sources  100  and powering the heating element  150 . 
         [0028]    Hence, it is also desirable that the controller/microprocessor is operative to develop a background noise profile used to discriminate the whistle sound from the background during a predetermined time period prior to the potential boiling of the fluid in the vessel. The time period may be predetermined from experience of prior heating cycles, or when the detected vessel temperature is approaching, but not close enough to the boiling point. By developing the background noise profile immediately before boiling is likely to be detected, it is also or the controller/microprocessor to determine that the current background noise is to large to accurately detect boiling by distinguishing the whistling characteristics, in which case it would be desirable if the system is operative to alert a user that the detected background noise is too large to be distinguished from a whistle sound, and that the system will not operate in the desired automated boil detection and control mode. In determining the duration of this background noise detection period, the temperature measurement can be made by a sensor immersed in the fluid/water contained in the vessel, or a thermal sensor built into the inner wall of the vessel. Such temperature measurements can also be used in any of the cooking modes described below, such as when the vessel is maintained at a lower predetermined temperature after boiling. 
         [0029]    The heat source  100  can be any burner with its output power controlled electronically. An induction burner has an advantage that its power output can be switched on/off instantly for optimal control but gas burner (with electronically controlled valve and ignition system) offers similar performance. 
         [0030]    It should be appreciated that the above aspects and features enable the following modes of cooking: 
         [0031]    A. Pasta cooking, in which the water is brought to a boil, and the user is alerted so they can then add the pasta. Then after water cools from the pasta and comes to a 2nd boil, the temperature or power is reduced or the user is alerted to observe the effects of the power reduction, or to manually reduce the power as desired. The user optionally indicates when pasta is added so the power returns to high to reheat the water to boiling, as well as for signaling when the pasta is completed, such as by the user setting a timer or pasta type via the control panel. The independent temperature sensors can also be used to monitor the subsequent cooling from adding pasta, and the reheating. 
         [0032]    B. Rice Cooking, in which the temperature is lowered after a simmer or boil is reached, and may optionally progress according to a predetermined time-temperature profile, such as to lower temperature keep the rice warm after cooking without drying, as well as provide an audible or/and or visual signal after cooking is complete 
         [0033]    C. Boil, and then immediately turn off, (Auto Off); 
         [0034]    D. Boil and then automatically simmer until manually shut off, or for a predetermined time programmed by the user. 
         [0035]    E. Simmer until manually shut off, or for a predetermined time programmed by the user. 
         [0036]    F. Any of the above modes A-E under either temperature monitored control, wherein the temperature is used to control the power level, such as under proportion-derivative-integral (PID) control to heat the contents to the predetermined or predetermined time temperature profile, or power mode, where the power is either constant or varies with time per a predetermined profile. 
         [0037]    While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be within the spirit and scope of the invention as defined by the appended claims.