Patent Publication Number: US-2006013933-A1

Title: Method for conducting a cooking process using a cooking process sensor

Description:
BACKGROUND  
      The disclosure relates to a method for conducting a cooking process in a cooking chamber of a cooking appliance using a cooking process probe which is to be inserted at least partly into an item being cooked in the cooking chamber for detecting at least one variable of the item being cooked and it relates to a cooking appliance in particular for carrying out said method.  
      An increasing number of cooking process probes are being used for conducting a cooking process. A cooking process probe is known for example from DE 299 23 215.8. To allow the possibilities of conducting a cooking process that are mentioned there to be fully exploited, it is a pre-requisite that the cooking process probe is actually inserted in the item being cooked. This is so because, if the cooking process probe is outside the item being cooked, the cooking result may be made considerably worse, since the cooking process probe does not pick up any actual information on the item being cooked. The problems of detecting non-insertion are already discussed in DE  100 61 821.9-34,  which is not a prepublished publication. In that case, temperature profiles detected by the sensors of the cooking process probe are evaluated, which does lead to satisfactory results but requires complicated software.  
      Further methods for detecting improper use of a cooking process probe are known from the prior art. For instance, a control device for cooking, roasting or baking processes with a food thermometer is known from DE 31 04 926 C2. This food thermometer comprises not only a sensor part having a temperature sensor but also an indicating device, by means of which the resistance of an item being cooked is measured and compared with a predefined reference value. If in this case the difference between the measured resistance value and the reference value exceeds a predefined threshold value, the conclusion is drawn that the cooking process probe is not in the item being cooked, and the cooking process is aborted. However, a disadvantage of the method used in this device is that false indications may occur. For instance, soiling of the indicating device may have the effect that the difference between the measured resistance value and the reference value lies below the predefined threshold value although the temperature sensor is not inside an item being cooked. This can lead to an undesired cooking result.  
      Furthermore, there are known cooking appliances in which mis-insertion of a cooking process probe is detected by a temperature measured by means of the cooking process probe being compared with a temperature prevailing in a cooking chamber. If the difference between these two measured temperatures lies below a predefined value, it is assumed that the cooking process probe has not been inserted correctly into the item being cooked. However, a disadvantage of the method used in these cooking appliances is that, in the case of a delta measurement, i.e. correction of the cooking chamber temperature on the basis of the temperature recorded by means of the cooking process probe, mis-insertion of the cooking process probe is possibly not detected.  
      In the not prepublished document WO 02/47 522 A2 of the applicant according to which temperature patterns of a surface temperature of an item being cooked, a core temperature of the item being cooked and/or a temperature of the cooking chamber are determined by means of a cooking process probe, to detect a non-insertion of the cooking process probe via the determined temperature pattern. Because of the necessity of the determination of temperature patterns a time offset in the detection of a non-insertion can occur which can influence the result of the cooking process negatively.  
      Also the not prepublished EP 1 271 061 A2 is based on the perception that by using temperature related information of a cooking process probe a non-insertion of the cooking process probe can be detected, which is associated with the same disadvantages known from the method of the WO 02/47 522 A2.  
      Finally, on the market there are also appliances for treating items being cooked which use a cooking process probe with its socket for connecting the cable to the cooking appliance arranged outside the cooking appliance. If the cooking process probe is not being used, the connector is closed by a cover. A cooking process with a cooking process probe line can only be started when the cooking process probe is connected to the cooking appliance via the connection. However, a disadvantage of these cooking appliances is that, in spite of the connection of the cooking process probe to a cooking appliance, a user can start the cooking process even if the cooking process probe has not been inserted into an item being cooked.  
     SUMMARY  
      It is an object to develop the method of the generic type further in such a way that the disadvantages of the prior art are overcome. It is also intended to provide a cooking appliance which is improved in comparison with the prior art for carrying out such a method.  
      The object relating to the method is achieved according to the invention by providing at at least one predetermined point in time a monitoring to detect non-insertion of the cooking process probe, at least one of 
          a parameter is detected for monitoring whether the cooking process probe is in a standby position in a retaining device provided by the cooking appliance or in a measuring position in a positioning device provided by an accessory part for receiving the item being cooked,     a parameter is detected for monitoring whether the cooking process probe is removed from the retaining device or the positioning device,     a parameter is detected for monitoring whether the cooking process probe is moved and/or where the cooking process probe is positioned inside the cooking appliance, and     a parameter is detected for monitoring whether the cooking process probe is being grasped; and        

      if non-insertion is detected, at least one of a first warning signal is emitted, a changeover is made to an emergency program and a cooking program is aborted. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  shows a cooking appliance;  
       FIG. 2  shows a first embodiment of a retaining device for a cooking process probe as part of the cooking appliance of  FIG. 1 ;  
       FIG. 3  shows a second embodiment of a retaining device;  
       FIG. 4  shows a third embodiment of a retaining device;  
       FIG. 5  shows a fourth embodiment of a retaining device;  
       FIG. 6  shows a fifth embodiment of a retaining device; and  
       FIG. 7  shows a cooking process probe for the cooking appliance of  FIG. 1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the preferred embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and/or method, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur now or in the future to one skilled in the art to which the invention relates.  
      To detect non-insertion of the cooking process probe, a monitoring is carried out to determine whether the cooking process probe is connected to the cooking appliance.  
      A particularly advantageous alternative embodiment of the method is characterized in that, the predetermined point in time is determined by the beginning of a cooking process, the end of a cooking process and/or an actuation, in particular opening or closing, of a cooking chamber door.  
      In the method, it may be provided in particular that, the detection is carried out over time and/or by forming time derivatives.  
      A further advantageous embodiment of the method provides that, to detect non-insertion of the cooking process probe, at least-one variable of the item being cooked is detected by means of the cooking process probe, a variation over time of the variable of the item being cooked and/or at least one derivative of the variation over time of the variable of the item being cooked is or are determined with respect to time, the determined variable of the item being cooked, and the determined variation over time and/or the determined derivative preferably being compared with at least one setpoint value.  
      Finally, it may be provided in the method that, dependent on the cooking process, a second warning signal is emitted if the cooking process probe is not placed in the retaining device, in order to call on an operator to place the cooking process probe in the retaining device, and/or a third warning signal is emitted if the cooking process probe is not placed in the positioning device, in order to call on an operator to place the cooking process probe in the positioning device.  
      The preferred embodiment also relates to a cooking appliance, in particular for carrying out a method with a cooking chamber, a cooking process probe which is to be inserted at least partly into an item being cooked in the cooking chamber for detecting at least one variable of the item being cooked. A non-insertion of the cooking process probe into the item being cooked is detectable by the use of 
          a sensor for monitoring whether the cooking process probe is in a standby position in a retaining device provided by the cooking appliance, or in a measuring position in a positioning device provided by an accessory part for receiving the item being cooked, and/or     a sensor for monitoring whether the cooking process probe has been removed form the retaining device or from the positioning device, and/or     a sensor for monitoring whether the cooking process probe is positioned inside the cooking appliance or whether the cooking process probe has been moved, and/or     a sensor for monitoring whether the cooking process probe has been grasped, and        

      If non-insertion is detected, at least a first warning signal can be emitted, a changeover can be made to an emergency program and/or the cooking program can be aborted for conducting a cooking process.  
      In this respect, it may be provided in particular that the sensor is comprised by the retaining device, the positioning device and/or the cooking process probe.  
      A cooking appliance may also be characterized by an input and/or output unit and/or an open-loop and/or closed-loop control unit in operative connection with the cooking process probe, a cooking chamber door, the sensor, the retaining device and/or the positioning device.  
      It is advantageously provided that the cooking process probe is captively connected to the cooking appliance.  
      Finally, a particularly advantageous embodiment of the cooking appliance is characterized by a cooling device, at least temporarily in operative connection with the cooking process probe and/or the retaining device, for cooling of at least one region of the cooking process probe.  
      The system and method is consequently based on the surprising finding that a method for detecting improper use of a cooking process probe, in particular non-insertion of the same into an item being cooked, can be carried out by being able to detect improper use at the beginning of a cooking process without a time delay, avoidance of detection by a user being at least made more difficult. In particular, use of the retaining device makes such detection possible for the cooking process probe in such a way that the application of a voltage or measurement of a conductivity value allows the determination of whether or not the cooking process probe is in the retainer, or has or has not been removed from it. In particular, comparison of the time of day of the removal and the start of the process at a time before or after it makes it possible for placement of the cooking process probe or omission of the same to be reliably assumed, and consequently improper use of the cooking process probe to be detected. In particular, the combination of various actions for handling the cooking process probe, not only detecting whether the cooking process probe has been removed from its holder, that is to say has been grasped, has been moved, has been positioned at any particular location and/or has been inserted into a cooking process probe holder of an accessory part, makes it possible for improper use of the cooking process probe to be detected essentially reliably.  
      Represented in  FIG. 1  is a cooking appliance  1  according to the invention with a cooking chamber  3 , which can be closed by means of a cooking chamber door  5 . Furthermore, the cooking appliance  1  comprises an input unit  7 , by means of which a user can operate the cooking appliance  1 . In particular, by means of the input unit  7 , a user can program, start or end a cooking process or alter individual cooking parameters during a cooking process. By means of an output unit  9 , information on the cooking appliance  1 , an item being cooked and/or a cooking process can be given to a user. For this purpose, the output unit  9  comprises a display for indicating cooking parameters and/or an acoustic output unit for producing warning and/or information signals. The cooking appliance  1  also comprises a cooking process probe  11 , which is captively connected by means of a cable  19  to the cooking appliance  1  in the cooking chamber  3 . This connection prevents the cooking process probe  11  from being removed from the cooking appliance  1  during normal operation. To carry out a cooking process, the cooking process probe  11  is inserted into an item  13  being cooked, such as a roast joint, in particular to pick up at least a core temperature and, if appropriate, a surface temperature of the item  13  being cooked, these temperature values being used for controlling the subsequent cooking process. If needed, positioning of the cooking process probe  11  may take place by means of a positioning device  15 , which can for example be fixedly connected to an accessory part  16  in the form of a metal sheet for carrying the item  13  being cooked. If the cooking process probe  11  is not used, in particular if no cooking process is being carried out, it can be deposited by a user in a standby position in a retaining device  17  fixedly connected to the cooking chamber  3 . The position of the cooking process probe  11  in the retaining device  17  is presented by dashed lines in  FIG. 1 .  
      Although in  FIG. 1  the retaining device  17  is represented inside the cooking chamber  3 , and the cooking process probe is connected to the cooking appliance  1  by means of a cable  19 , the retaining device may be arranged at any desired position of the cooking appliance and the cooking process probe may be wirelessly connected to the cooking appliance for the transmission of data on the item being cooked. The captivity of the cooking process probe is achieved by a warning sound being emitted from the output unit when the cooking process probe is removed from the cooking appliance.  
      The cooking appliance  1  also comprises a closed-loop control unit (not represented), by means of which it is possible, inter alia, to control a cooking process carried out in the cooking appliance  1 . This control of the cooking process also comprises the method, by which improper use of the cooking process probe can be detected. In this respect, it is taken into account that, when carrying out a cooking process with the cooking process probe  11 , a user should perform essentially predetermined actions on the cooking appliance  1 , in particular on the cooking process probe  11 . This is so because, before the beginning of a cooking process, a user should first open the cooking chamber door  5  and position the item  13  being cooked inside the cooking chamber  3 . Subsequently, the user should remove the cooking process probe  11  from the retaining device  17  and insert it in the item  13  being cooked, in particular by means of the positioning device  15 . Subsequently, the user should close the cooking chamber  3  by means of the cooking chamber door  5  and start the cooking process by means of the input  7 , if appropriate after a time delay. During the subsequent cooking process, the cooking process probe  11  should remain essentially stationary in the item  13  being cooked and only once the cooking process has ended and the cooking chamber door  5  is opened should it be grasped by the user, and if appropriate removed from the positioning device  15  and inserted into the retaining device  17 . If these desired actions for handling the cooking process probe do not take place during a cooking process, poor or even harmful cooking results may occur.  
      The method now offers the possibility of detecting when at least one desired action for handling the cooking process probe that is necessary for its proper use does not take place or it is mishandled, and of reacting to this, such as by emitting warning signals, changing over to an emergency program or aborting a cooking process.  
      A first desired action for handling the cooking process probe  11  is for example to remove the cooking process probe  11  from the retaining device  17 , which of course presupposes that the cooking process probe  11  is in the retaining device  17  in the first place. If, however, the cooking process probe  11  is still in the retaining device  17  at the beginning of a cooking process, improper use of the cooking process probe  11  can always be directly concluded. Furthermore, improper use of the cooking process probe  11  can also be concluded for example if removal of the cooking process probe  11  from the retaining device  17  has taken place outside a specific time period before the beginning of the cooking process or the programming of the cooking process or the closing of the cooking chamber door  5 . In such a case, it must be assumed that the cooking process probe  11  has not been inserted into the item  13  being cooked.  
      Represented in  FIG. 2  is a first embodiment according to the invention of a retaining device  17 ′. The retaining device  17 ′ is fixedly attached to a cooking appliance wall  20  and comprises two fork-shaped holders  21 ,  23 , which are designed as clips for receiving the cooking process probe  11 . At least the surface regions of the holders  21 ,  23  which come into contact with the cooking process probe  11  (not shown) when it is inserted are comprised of a conductive material and consequently form contacts  25  and  27 , respectively. The remaining regions of the holders  21  and  23  are preferably electrically insulated on the outside. The contacts  25  and  27  are connected to the closed-loop control unit via lines  29  and  31  in such a way that the contact  25  is at a potential of, for example, 12 volts, while the contact  27  is at a potential of, for example, 5 volts or ground. If the cooking process probe  11  is not in the retaining device  17 , as represented, no current flow occurs between the contacts  25  and  27 . Consequently, it can be concluded from the absence of a current flow between the contacts  25  and  27  that the cooking process probe  11  is not located inside the retaining device  17 . If, on the other hand, the cooking process probe  11  is introduced into the holders  21  and  23  of the retaining device  17 , a current flow between the contacts  25  and  27  occurs via the conductive surface of the cooking process probe  11 .  
      Represented in  FIG. 3  is a second retaining device  32 . By contrast with the first retaining device  17 ′, represented in  FIG. 2 , the second retaining device  32  comprises two annular holders  21 ′ and  23 ′, respectively. These in turn comprise contacts  25 ′ and  27 ′, respectively, which are connected to the closed-loop control unit via the lines  29  and  31 . By contrast with the first retaining device  17 ′ represented in  FIG. 2 , the cooking process probe  11  cannot be clipped into the second retaining device  32 , but must first be passed from above through the holder  21 ′ and with the tip through the holder  23 ′. The contacts  25 ′ and  27 ′ are at different potentials, so that presence of the cooking process probe  11  in the retaining device  32  can be concluded from a current flow between the contacts  25 ′ and  27 ′ via the surface of the cooking process probe  11 .  
      Represented in  FIG. 4  is a third retaining device  33 . In this case, a fork-shaped holder, comprising two fork prongs  34  and  35 , is fastened to the cooking appliance wall  20 . The fork prongs  34 ,  35  have contacts  25 ″ and  27 ″, which are connected to the closed-loop control unit via the lines  29 ,  31 . The contacts  25 ″ and  27 ″ are likewise at different potentials, so that no current flow can occur between the contacts  27 ″ and  25 ″ if the cooking process probe  11  is not located inside the holder. On the other hand, when the cooking process probe  11  is inserted into the retaining device  33 , a current flow occurs between the contacts  25 ″ and  27 ″ via the surface of the cooking process probe  11 .  
      Represented in  FIG. 5  is a fourth retaining device  36 . This retaining device  36  comprises annular holders  37  and  39 . By contrast with the holders represented in FIGS.  2  to  4 , the holders  37  and  39  have no contacts, but sensors  41  and  43 , which are connected to the closed-loop control unit of the cooking appliance  1  via a line  45 , are arranged on one holder  39 . The sensors  41  and  43  comprise reed contacts, which are closed when the cooking process probe  11  is inserted with its tip through the holder  37  into the holder  39 . The closing of the reed contacts has the effect for the method according to the invention of detecting that the cooking process probe  11  is located in the retaining device  36 .  
      Represented in  FIG. 6  is a fifth retaining device  47  according to the invention. This retaining device  47  comprises two fork-shaped holders  49 ,  51 , into which the cooking process probe  11  can be clipped. Arranged between the holders  49  and  51  is a sensor  53 . When the cooking process probe  11  is inserted into the holder  49  or  51 , this closes the contact of the sensor  53 , which is connected to the closed-loop control unit of the cooking appliance via a line  55 . Closing of the contact means that the cooking process probe  11  is located in the holder  47 .  
      The insertion of the cooking process probe  11  into the positioning device  15  represents a second desired action for handling the cooking process probe  11 . This is so because, if when the positioning device  15  is being used the cooking process probe  11  is not inserted into it, improper use of the cooking process probe  11  can likewise be concluded.  
      Furthermore, improper use of the cooking process probe  11  can be concluded if the cooking process probe  11  is not moved in the time period in which the cooking chamber door  5  is open, the item  13  being cooked is introduced into the cooking chamber  3  and the cooking chamber door  5  is closed, since a corresponding movement represents a third desired handling action. It is then to be assumed that, although the cooking process probe  11  is inside the cooking chamber  3 , it is outside the item  13  being cooked. Monitoring of the movement of the cooking process probe  11  may take place either by means of a movement sensor (not shown) arranged in the cooking process probe  11  or an electronic locating system for the cooking process probe  11  (not shown) arranged in the cooking appliance  1 . Such a locating system also makes it possible in principle to establish whether the cooking process probe  11  is located inside or outside the cooking chamber  3 .  
      A fourth desired handling action is that of grasping the cooking process probe  11 , which likewise allows conclusions to be drawn concerning improper use of the cooking process probe  11 . To detect this desired handling action, the cooking process probe  11  may comprise, for example, a conductivity sensor (not shown), which makes it possible to establish grasping of the cooking process probe  11  by a user. If such grasping does not occur, for example during the time period in which the cooking chamber door  5  is open, it can likewise be assumed that the cooking process probe  11  has not been inserted into the item  13  being cooked.  
      Also represented in  FIG. 7  is a cooking process probe  11 ′ which comprises a number of temperature sensors (not represented) in its needle-shaped tip  57  and has a conductivity sensor  61  arranged on its recessed grip  59 . If a user grasps the cooking process probe  11 ′ at the recessed grip  59 , he touches the conductivity sensor  61 , which then detects a change in conductivity. This leads to a detection of grasping of the cooking process probe  11 ′, which can be processed in the method.  
      The cooking process probe can advantageously be cooled by means of a cooling device (not represented), in order to make grasping of the recessed grip  59  more comfortable and/or to avoid an item being cooked from being damaged by insertion of a hot needle-shaped tip  57 .  
      It may also be provided that the positioning device  15  has at least one of the design features represented in the exemplary embodiments of the retaining device.  
      Consequently, by monitoring various desired handling actions or mishandling actions, in particular of the cooking process probe  11 , the method makes it possible to detect improper use, in particular non-insertion, of the same.  
      While a preferred embodiment has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention both now or in the future are desired to be protected.