EP2438796B1 - Hob comprising a temperature sensor - Google Patents

Hob comprising a temperature sensor Download PDF

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Publication number
EP2438796B1
EP2438796B1 EP10721505.5A EP10721505A EP2438796B1 EP 2438796 B1 EP2438796 B1 EP 2438796B1 EP 10721505 A EP10721505 A EP 10721505A EP 2438796 B1 EP2438796 B1 EP 2438796B1
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EP
European Patent Office
Prior art keywords
temperature
heating
phase
control unit
cookware element
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EP10721505.5A
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German (de)
French (fr)
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EP2438796A1 (en
Inventor
Oscar Luis Aldana Arjol
Sergio Llorente Gil
David Paesa García
Carlos Sagües Blázquiz
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BSH Hausgeraete GmbH
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BSH Hausgeraete GmbH
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B1/00—Details of electric heating devices
    • H05B1/02—Automatic switching arrangements specially adapted to apparatus ; Control of heating devices
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B1/00—Details of electric heating devices
    • H05B1/02—Automatic switching arrangements specially adapted to apparatus ; Control of heating devices
    • H05B1/0227—Applications
    • H05B1/0252—Domestic applications
    • H05B1/0258—For cooking
    • H05B1/0269—For heating of fluids
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/06—Control, e.g. of temperature, of power
    • H05B6/062—Control, e.g. of temperature, of power for cooking plates or the like
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2213/00—Aspects relating both to resistive heating and to induction heating, covered by H05B3/00 and H05B6/00
    • H05B2213/07—Heating plates with temperature control means

Definitions

  • the invention relates to a hob with at least one heating zone and a temperature sensor according to the preamble of claim 1 and a method for operating a hob according to the preamble of claim 7.
  • a system for detecting the temperature of a cooking appliance over a radiant hob is already known.
  • the system has an upper surface and a lower surface and a radiant heating element for heating.
  • a temperature sensor adjacently disposed on the lower surface of the cooktop is arranged to detect a temperature of the lower surface of the cooktop.
  • the system further includes a thermal isolation barrier disposed between the temperature sensor and the radiant heater.
  • the US document U.S. 4,493,980A discloses a power control assembly for an automatic surface unit in a cooking appliance that allows a user to select cooking modes of "heat,”"simmer,””boil,” and “fry” and select from a variety of heating temperature settings for each mode.
  • the heating-temperature settings of each mode are associated with a minimum equilibrium temperature and an equilibrium performance level.
  • the control system compares the output of a cooker temperature sensor with various reference values selected based on mode and heating setting. Depending on the result of the comparison, the surface unit is operated at the respective equilibrium power level or at a non-steady state power level to bring the temperature of the cooking appliance to the desired temperature for the selected mode and temperature setting, with minimal temperature overrun.
  • the international patent application WO 2005/028963 A1 discloses a method for controlling a cooking level in an electric cooking arrangement.
  • the arrangement comprises an electric heating unit having an electric heating element and a temperature-sensitive device adapted to monitor the temperature of a cooking appliance and which in turn comprises a temperature sensor element.
  • the arrangement further comprises a manual selection input means by means of which a plurality of predetermined cooking levels can be selected by the user.
  • Each predetermined cooking level corresponds to a predetermined temperature, which is detected by the temperature sensor element, wherein the predetermined temperature is offset relative to an actual, the respective cooking level corresponding temperature.
  • the cooking level is controlled by energizing the heating unit at a corresponding power level.
  • a hob with a heating zone and a temperature sensor arranged in the center of the heating zone.
  • a method is described in which a point in time at which the liquid arranged in the cookware element reaches a boiling point is predicted with the highest possible accuracy.
  • the cooking content of the cookware is avoided by reducing the heating energy supply before reaching the boiling point or boiling point.
  • the prediction is based on the evaluation of characteristic temperature curves recorded in the past.
  • the boiling points of different liquids can vary greatly.
  • precise prediction of the boiling point is important. Simmering can save a lot of energy compared to bubbly cooking because the evaporation energy released by cooking can be very high.
  • the temperature of the food is too low and the difference in temperature of the food to the boiling point is too large, the cooking process is prolonged and / or leads to undesirable results.
  • the invention is therefore in particular the object of enabling an energy-saving Simmer compassion with a precisely matched to the boiling temperature of the cookware contents target temperature.
  • the object is achieved in particular by the features of the independent claims.
  • Advantageous embodiments and modifications of the invention will become apparent from the dependent claims.
  • the invention is based on a hob with at least one heating zone, a temperature sensor for detecting the temperature of a cooking utensil element placed on the heating zone and a control unit for operating the heating zone.
  • the control unit is designed to heat the cookware element in a heating phase in at least one operating mode and to regulate the temperature of the cooking utensil element in a holding phase to a desired temperature.
  • control unit is designed to detect a boiling temperature of the liquid contained in the cookware element during the heating phase and to determine the setpoint temperature depending on the boiling temperature.
  • the boiling temperature should therefore be measured in the heating phase itself and not in complex experimental runs with other cookware contents.
  • error-prone predictions and estimates of the boiling temperature can be dispensed with.
  • the heating phase therefore lasts at least until the boiling temperature is reached. Because by the direct Measuring the boiling temperature Errors in the forecast or estimation of the boiling temperature can be avoided, the boiling temperature is determined with high precision.
  • the setpoint temperature of the heating phase which may in particular be a simmering temperature, can thus be precisely determined depending on the boiling temperature.
  • the setpoint temperature can be selected smaller by a predetermined temperature difference than the boiling temperature.
  • the temperature difference may in particular be between 2 ° and 7 ° C.
  • the control unit For detecting the boiling temperature, the control unit records a temperature profile of the cooking utensil element during the heating phase and detects a substantially constant section in the temperature profile. When the boiling temperature is reached, the temperature of the cookware contents does not increase any further, resulting in a constant temperature of the cookware outside.
  • the measured value for the boiling temperature is a temperature averaged in the constant section.
  • the signal of the temperature sensor can generally be filtered and / or averaged in a manner which appears to be suitable to a person skilled in the art or subjected to suitable scale transformation.
  • control unit For detecting the constant portion of the temperature profile, the control unit can in particular form a gradient of the temperature profile.
  • the temperature profile can be classified as "substantially constant” if the gradient is below a certain threshold.
  • a safety shutdown can be ensured if the control unit is designed to switch off the operating mode and to generate a warning signal if the temperature detected by the temperature sensor exceeds a maximum value.
  • this maximum value may be around 150 ° C. Exceeding the maximum value indicates that the cookware element is empty so that boiling can not occur.
  • a further aspect of the invention relates to a method for operating a hob with at least one heating zone, a temperature sensor for detecting the temperature a cookware element placed on the heating zone and a control unit. It is heated in at least one operating mode, the cookware element in a heating phase and the temperature of the cooking utensil element is controlled in a holding phase to a desired temperature.
  • a boiling temperature of the liquid contained in the cookware element is detected during the heating phase and the setpoint temperature is determined as a function of the boiling temperature.
  • Fig. 1 shows a hob with a heating zone 10, a temperature sensor 12 for detecting the wall temperature of a set up on the heating zone cooking utensil 14 and a control unit 16.
  • the heating zone 10 is a marked on a cover plate 18 of the hob, its position and size of the position and size an arranged below the cover 18 inductor 20 corresponds.
  • the hob is an induction hob and the inductor 20 receives a high frequency heating current from an inverter 22. Between a household power grid connection 34 and the inverter 22, a rectifier, not shown here is arranged.
  • the control unit 16 determines the frequency and / or the amplitude of the heating current generated by the inverter 22 so that a certain heating power is generated in the time average.
  • the heating current generated via the inductor 20, a high-frequency alternating magnetic field, which in turn generates high-frequency eddy currents in the bottom of the cooking utensil element 14.
  • the cookware element 14 is heated by the dissipation of these eddy currents.
  • the temperature sensor 12 is a tower-like above the top of the cover 18 also protruding infrared temperature sensor which detects infrared radiation emitted from a side wall of the cooking utensil element 14.
  • the signal detected by the sensor 12 is processed by a sensor readout unit 24 and forwarded to the control unit 16.
  • the sensor readout unit 24 may, for example, perform a low-pass filtering and / or a scale transformation.
  • the temperature sensor is formed as arranged under the cover plate 18 NTC element or arranged as the cover plate infrared sensor. Furthermore, it is conceivable to attach the temperature sensor 12 directly to the wall of the cookware element 14.
  • the control unit 16 is a universally programmable arithmetic unit that executes a software implemented method for operating the cooktop. There are different modes of operation in the method. In a particular operating mode, which could also be referred to as a simmer mode, the cookware element 14 is heated in a heating phase 26 until a liquid 28 in the cookware element 14 reaches its boiling temperature TB.
  • the control unit 16 holds the cookware element 14 only at the boiling temperature TB until it has been determined with sufficient accuracy. Subsequently, the control unit 16 switches from the heating phase 26 into a holding phase 32 in which the temperature of the cookware element 14 or of the liquid 28 is regulated to a desired temperature TS. To form a closed loop feedback from the temperature sensor 12 is used.
  • the relationship between the temperature of the liquid 28 and the temperature of the cooking utensil element 14 and the temperature of the radial outer wall of the cooking utensil element 14 can be determined via an empirically determined function.
  • the radiation losses of the outer wall result in a proportionality between the wall temperature of the cookware element 14 and the temperature of the liquid 28, which can be expressed by a constant factor.
  • it is of secondary importance which value the boiling temperature TB of the liquid 28 itself has. What is essential is the precise determination of the outside temperature of the cooking utensil element 14, which occurs when the boiling temperature TB is reached. Because of the proportionality of the two temperatures TB, TS both can be used equivalently.
  • Fig. 2 shows the time course of a heating power (solid line), the temperature of the liquid 28 (dashed line) and the temperature of the wall of the cookware element 14 (dotted line).
  • the liquid 28 reaches the boiling temperature TB at a time t1 and the temperature of the liquid 28 of the cooking utensil element 14 is substantially constant in a section 30 of the temperature profile.
  • the control unit 16 averages the temperature measured in this section 30 by the temperature sensor 12 and stores this temperature as the boiling temperature TB or the boiling temperature associated wall temperature of the cookware element 14.
  • the control unit 16 switches to the holding phase 32, in which the liquid 28 is kept as constant as possible at a desired temperature TS. This is done in a closed loop.
  • the temperature of the liquid decreases briefly, but is increased again to the setpoint temperature TS. If the drop in temperature is too great, in one embodiment of the invention, a re-detection of the boiling temperature may take place to possibly accommodate a changed composition of the liquid.
  • the control unit 16 determines the target temperature by subtracting a predetermined stored value from the previously detected boiling temperature TB. This subtracted temperature difference can be, for example, 5 ° C., so that a target temperature of 95 ° C. results for pure water under standard atmospheric pressure. Be at 95 ° C Food is cooked substantially in the same way as in bubbly boiling water at 100 ° C, so that evaporation energy can be saved without significantly affecting the cooking process.
  • Fig. 3 shows a flowchart for carrying out the method according to the invention.
  • the retractable in the cover plate temperature sensor 12 is activated and moved from its retracted position upwards into an activation position.
  • the heating phase 26 is started.
  • the temperature of the outer wall of the cooking utensil element 14 is measured and, in a step S4, an estimated value for the temperature of the liquid 28 is determined from this temperature by multiplying it by a constant.
  • the control unit 16 judges whether the liquid 28 is boiling or not. For this purpose, the control unit 16 evaluates the temperature recorded after the last measurements and checks whether this is constant except for unavoidable fluctuations. If this is the case, the boiling temperature TB is reached. If not, the process jumps to step S3 and re-measures. If a temperature is detected in step S5 which is above a maximum temperature, an emergency shutdown occurs (not shown).
  • step S5 the control unit 16 calculates the set temperature TS for the liquid 28 in a step S6 and goes to the holding phase 32 in a step S7.
  • the temperature of the cooking utensil element is determined in a step S8 14 measured, calculated in a step S9 from the temperature of the cooking utensil element 14, the temperature of the liquid 28 and regulated in step S10 depending on the result, the heating power. If the temperature of the liquid 28 is above the target temperature, the heating power of the inductor 20 is reduced by a variation of the frequency of the inverter 22. If the temperature is below the target temperature TS, the heating energy of the inductor 20 is increased. After adjusting the heating energy, the process returns to step S8.

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Cookers (AREA)
  • Induction Heating Cooking Devices (AREA)
  • Electric Stoves And Ranges (AREA)

Description

Die Erfindung betrifft ein Kochfeld mit wenigstens einer Heizzone und einem Temperatursensor nach dem Oberbegriff des Anspruchs 1 und ein Verfahren zum Betreiben eines Kochfelds nach dem Oberbegriff des Anspruchs 7.The invention relates to a hob with at least one heating zone and a temperature sensor according to the preamble of claim 1 and a method for operating a hob according to the preamble of claim 7.

Aus der US-Druckschrift US 2005/286609 A1 ist bereits ein System zur Detektion der Temperatur eines Kochgeräts über einem Strahlungs-Kochfeld bekannt. Das System weist eine obere Oberfläche und eine untere Oberfläche sowie ein zur Erhitzung vorgesehenes Strahlungsheizelement auf. Ein der unteren Oberfläche des Kochfelds benachbart angeordneter Temperatursensor ist dazu vorgesehen, eine Temperatur der unteren Oberfläche des Kochfelds zu detektieren. Das System umfasst des Weiteren eine Wärmeisolationsbarriere, welche zwischen dem Temperatursensor und dem Strahlungsheizelement angeordnet ist.From the US publication US 2005/286609 A1 A system for detecting the temperature of a cooking appliance over a radiant hob is already known. The system has an upper surface and a lower surface and a radiant heating element for heating. A temperature sensor adjacently disposed on the lower surface of the cooktop is arranged to detect a temperature of the lower surface of the cooktop. The system further includes a thermal isolation barrier disposed between the temperature sensor and the radiant heater.

Die US-Druckschrift US 4 493 980 A offenbart eine Leistungssteuerungsanordnung für eine automatische Oberflächeneinheit in einem Kochhaushaltsgerät, welche es einem Nutzer ermöglicht, Kochmodi "Wärmen", "Köcheln", "Sieden" und "Braten" auszuwählen und für jeden Modus aus einer Vielzahl von Heiz-Temperatur-Einstellungen zu wählen. Den Heiz-Temperatur-Einstellungen eines jeweiligen Modus sind eine minimale Gleichgewichts-Temperatur und ein Gleichgewichts-Leistungsniveau zugeordnet. Das Steuerungssystem vergleicht die Ausgabe eines Kochgerät-Temperatursensors mit verschiedenen Referenzwerten, welche anhand von Modus und Heizeinstellung gewählt wurden. In Abhängigkeit von dem Ergebnis des Vergleichs wird die Oberflächeneinheit mit dem entsprechenden Gleichgewichts-Leistungsniveau oder mit einem nicht-stationären Leistungsniveau betrieben, um die Temperatur des Kochgeräts - bei minimaler Temperaturüberschreitung - auf die für den ausgewählten Modus und die ausgewählte Heizeinstellung gewünschte Temperatur zu bringen.The US document U.S. 4,493,980A discloses a power control assembly for an automatic surface unit in a cooking appliance that allows a user to select cooking modes of "heat,""simmer,""boil," and "fry" and select from a variety of heating temperature settings for each mode. The heating-temperature settings of each mode are associated with a minimum equilibrium temperature and an equilibrium performance level. The control system compares the output of a cooker temperature sensor with various reference values selected based on mode and heating setting. Depending on the result of the comparison, the surface unit is operated at the respective equilibrium power level or at a non-steady state power level to bring the temperature of the cooking appliance to the desired temperature for the selected mode and temperature setting, with minimal temperature overrun.

Aus der US-Druckschrift US 6 462 316 B1 ist bereits ein System zur automatischen Steuerung der Temperatur einer Kochfläche eines Festkörperoberflächen-Kochfelds sowie, anhand davon, der Temperatur eines Kochgeräts auf der Kochfläche, durch eine Detektion von Kochgerät-Eigenschaften durch das Festkörperoberflächen-Kochfeld bekannt. Die Kochgerät-Eigenschaften umfassen Vorhandensein/Nichtvorhandensein, Wegnehmen/Aufstellen und andere physische Eigenschaften wie Gerätetyp, Größe, Ausbeulung, Temperatur und Befüllungsgröße. Die automatische Steuerung erfolgt anhand einer Überwachung der Wärmeübertragungskennlinien von der Energiequelle zum Kochfeld und zum Gerät, um so auf die Eigenschaften des Geräts zu schließen. Dies wird erreicht, indem ein Parameter detektiert oder berechnet wird, der die Temperatur eines überwachten Bereichs, welcher zumindest einen Teil des Kochfelds oder des auf der oberen Oberfläche des Kochfelds aufgestellten Kochgeräts umfasst, angibt. Zudem wird dies erreicht, indem ein Parameter, welcher eine Leistung angibt, mit der eine steuerbare Wärmequelle beaufschlagt wird, und indem Signaleigenschaften mittels eines evolutionären Algorithmus detektiert werden.From the US publication US 6,462,316 B1 There is already known a system for automatically controlling the temperature of a cooking surface of a solid surface cooking hob and, based thereon, the temperature of a cooking utensil on the cooking surface by detecting cooking utensil characteristics through the solid surface cooking hob. The Cooking device features include presence / absence, removal / placement, and other physical characteristics such as device type, size, bulge, temperature, and fill size. The automatic control is based on monitoring the heat transfer characteristics from the power source to the hob and the appliance, to infer the characteristics of the appliance. This is accomplished by detecting or calculating a parameter indicative of the temperature of a monitored area comprising at least a portion of the cooktop or cooking appliance installed on the top surface of the cooktop. Moreover, this is achieved by providing a parameter indicative of a power applied to a controllable heat source and detecting signal characteristics by means of an evolutionary algorithm.

Die internationale Patentanmeldung WO 2005/028963 A1 offenbart ein Verfahren zur Steuerung eines Kochniveaus in einem elektrischen Kocharrangement. Das Arrangement umfasst eine elektrische Heizeinheit, welche ein elektrisches Heizelement und eine temperatursensitive Vorrichtung aufweist, die dazu eingerichtet ist, die Temperatur eines Kochgeräts zu überwachen und die ihrerseits ein Temperatursensorelement aufweist. Das Arrangement umfasst ferner ein manuelles Auswahleingabemittel, mittels dessen eine Vielzahl von vorgegebenen Kochniveaus durch den Nutzer ausgewählt werden kann. Jedem vorgegebenen Kochniveau entspricht eine vorgegebene Temperatur, welche durch das Temperatursensorelement detektiert wird, wobei die vorgegebene Temperatur relativ zu einer tatsächlichen, dem jeweiligen Kochniveau entsprechenden Temperatur versetzt ist. Das Kochniveau wird gesteuert, indem die Heizeinheit auf einem entsprechenden Leistungsniveau mit Energie beaufschlagt wird.The international patent application WO 2005/028963 A1 discloses a method for controlling a cooking level in an electric cooking arrangement. The arrangement comprises an electric heating unit having an electric heating element and a temperature-sensitive device adapted to monitor the temperature of a cooking appliance and which in turn comprises a temperature sensor element. The arrangement further comprises a manual selection input means by means of which a plurality of predetermined cooking levels can be selected by the user. Each predetermined cooking level corresponds to a predetermined temperature, which is detected by the temperature sensor element, wherein the predetermined temperature is offset relative to an actual, the respective cooking level corresponding temperature. The cooking level is controlled by energizing the heating unit at a corresponding power level.

Aus der DE 10 2006 057 885 A1 ist ein Kochfeld mit einer Heizzone und einem im Zentrum der Heizzone angeordneten Temperatursensor bekannt. Es wird ein Verfahren beschrieben, in dem ein Zeitpunkt, in welchem die in dem Kochgeschirrelement angeordnete Flüssigkeit einen Siedepunkt erreicht, mit möglichst hoher Genauigkeit vorhergesagt wird. Das Kochen des Kochgeschirrinhalts wird dadurch vermieden, dass vor dem Erreichen des Kochpunkts bzw. Siedepunkts die Heizenergiezufuhr verringert wird. Die Vorhersage basiert auf der Auswertung von in der Vergangenheit aufgezeichneten charakteristischen Temperaturkurven.From the DE 10 2006 057 885 A1 is known a hob with a heating zone and a temperature sensor arranged in the center of the heating zone. A method is described in which a point in time at which the liquid arranged in the cookware element reaches a boiling point is predicted with the highest possible accuracy. The cooking content of the cookware is avoided by reducing the heating energy supply before reaching the boiling point or boiling point. The prediction is based on the evaluation of characteristic temperature curves recorded in the past.

In der Praxis können sich aber die Siedepunkte verschiedener Flüssigkeiten beispielsweise abhängig von deren Zusammensetzung und/oder abhängig vom aktuellen Atmosphärendruck stark unterscheiden. Gleiches gilt für den Verlauf von Temperaturkurven, der auch durch das Hinzufügen von Zutaten während des Aufheizens für die Steuereinheiten des Kochfelds unvorhersagbar ist. Zum Realisieren eines effektiven Simmerbetriebs des Kochfelds, in dem der Inhalt des Kochgeschirrelements auf einer Temperatur knapp unterhalb des Siedepunkts gehalten wird, ist aber eine präzise Vorhersage des Siedepunkts wichtig. Durch den Simmerbetrieb kann im Vergleich zu sprudelndem Kochen sehr viel Energie eingespart werden, da die durch das Kochen abgegebene Verdampfungsenergie sehr hoch sein kann. Wenn allerdings die Temperatur des Garguts zu niedrig ist und die Differenz der Temperatur des Garguts zum Siedepunkt zu groß ist, wird der Garvorgang in die Länge gezogen und/oder führt zu unerwünschten Ergebnissen.In practice, however, the boiling points of different liquids, for example, depending on their composition and / or depending on the current atmospheric pressure can vary greatly. The same applies to the course of temperature curves, which is unpredictable even by the addition of ingredients during heating for the control units of the hob. However, in order to realize an effective simmer operation of the cooktop, in which the contents of the cookware element are kept at a temperature just below the boiling point, precise prediction of the boiling point is important. Simmering can save a lot of energy compared to bubbly cooking because the evaporation energy released by cooking can be very high. However, if the temperature of the food is too low and the difference in temperature of the food to the boiling point is too large, the cooking process is prolonged and / or leads to undesirable results.

Der Erfindung liegt daher insbesondere die Aufgabe zugrunde, einen energiesparenden Simmerbetrieb mit einer präzise auf die Siedetemperatur des Kochgeschirrinhalts abgestimmten Solltemperatur zu ermöglichen. Die Aufgabe wird insbesondere durch die Merkmale der unabhängigen Ansprüche gelöst. Vorteilhafte Ausgestaltungen und Weiterbildungen der Erfindung ergeben sich aus den Unteransprüchen.The invention is therefore in particular the object of enabling an energy-saving Simmerbetrieb with a precisely matched to the boiling temperature of the cookware contents target temperature. The object is achieved in particular by the features of the independent claims. Advantageous embodiments and modifications of the invention will become apparent from the dependent claims.

Die Erfindung geht insbesondere aus von einem Kochfeld mit wenigstens einer Heizzone, einem Temperatursensor zum Detektieren der Temperatur eines auf die Heizzone aufgestellten Kochgeschirrelements und einer Steuereinheit zum Betreiben der Heizzone. Die Steuereinheit ist dazu ausgelegt, in zumindest einem Betriebsmodus das Kochgeschirrelement in einer Aufheizphase aufzuheizen und die Temperatur des Kochgeschirrelements in einer Haltephase auf eine Solltemperatur zu regeln.In particular, the invention is based on a hob with at least one heating zone, a temperature sensor for detecting the temperature of a cooking utensil element placed on the heating zone and a control unit for operating the heating zone. The control unit is designed to heat the cookware element in a heating phase in at least one operating mode and to regulate the temperature of the cooking utensil element in a holding phase to a desired temperature.

Es wird vorgeschlagen, dass die Steuereinheit dazu ausgelegt ist, während der Aufheizphase eine Siedetemperatur der in dem Kochgeschirrelement enthaltenen Flüssigkeit zu detektieren und die Solltemperatur abhängig von der Siedetemperatur zu bestimmen. Die Siedetemperatur soll demnach in der Aufheizphase selbst und nicht etwa in aufwändigen Versuchsdurchgängen mit anderem Kochgeschirrinhalt gemessen werden. Durch das direkte Detektieren der Siedetemperatur kann auf fehleranfällige Vorhersagen und Abschätzungen der Siedetemperatur verzichtet werden. Die Aufheizphase dauert demnach zumindest so lange an, bis die Siedetemperatur erreicht ist. Da durch die direkte Messung der Siedetemperatur Fehler in der Vorhersage bzw. Abschätzung der Siedetemperatur vermieden werden können, wird die Siedetemperatur mit einer hohen Präzision bestimmt. Die Solltemperatur der Heizphase, die insbesondere eine Simmertemperatur sein kann, kann so abhängig von der Siedetemperatur präzise bestimmt werden.It is proposed that the control unit is designed to detect a boiling temperature of the liquid contained in the cookware element during the heating phase and to determine the setpoint temperature depending on the boiling temperature. The boiling temperature should therefore be measured in the heating phase itself and not in complex experimental runs with other cookware contents. By directly detecting the boiling temperature, error-prone predictions and estimates of the boiling temperature can be dispensed with. The heating phase therefore lasts at least until the boiling temperature is reached. Because by the direct Measuring the boiling temperature Errors in the forecast or estimation of the boiling temperature can be avoided, the boiling temperature is determined with high precision. The setpoint temperature of the heating phase, which may in particular be a simmering temperature, can thus be precisely determined depending on the boiling temperature.

Insbesondere kann die Solltemperatur um eine vorgegebene Temperaturdifferenz kleiner gewählt werden als die Siedetemperatur. Dadurch kann der mit dem sprudelnden Kochen einhergehende Energieverbrauch vermieden und ein schneller Garvorgang gewährleistet werden. Die Temperaturdifferenz kann insbesondere zwischen 2° und 7° C liegen.In particular, the setpoint temperature can be selected smaller by a predetermined temperature difference than the boiling temperature. As a result, the energy consumption associated with the bubbly cooking can be avoided and a quick cooking process can be ensured. The temperature difference may in particular be between 2 ° and 7 ° C.

Zum Detektieren der Siedetemperatur zeichnet die Steuereinheit während der Aufheizphase einen Temperaturverlauf des Kochgeschirrelements auf und detektiert einen im Wesentlichen konstanten Abschnitt in dem Temperaturverlauf. Beim Erreichen der Siedetemperatur erhöht sich die Temperatur des Kochgeschirrinhalts nicht weiter, was zu einer konstanten Temperatur der Kochgeschirr-Außenseite führt. Als Messwert für die Siedetemperatur wird eine in dem konstanten Abschnitt gemittelte Temperatur verwendet. Das Signal des Temperatursensors kann generell in einer dem Fachmann als geeignet erscheinenden Weise gefiltert und/oder gemittelt werden bzw. geeigneten Skalentransformation unterworfen werden.For detecting the boiling temperature, the control unit records a temperature profile of the cooking utensil element during the heating phase and detects a substantially constant section in the temperature profile. When the boiling temperature is reached, the temperature of the cookware contents does not increase any further, resulting in a constant temperature of the cookware outside. The measured value for the boiling temperature is a temperature averaged in the constant section. The signal of the temperature sensor can generally be filtered and / or averaged in a manner which appears to be suitable to a person skilled in the art or subjected to suitable scale transformation.

Zum Detektieren des konstanten Abschnitts des Temperaturverlaufs kann die Steuereinheit insbesondere einen Gradienten des Temperaturverlaufs bilden. Der Temperaturverlauf kann als "im Wesentlichen konstant" klassifiziert werden, wenn der Gradient unterhalb eines bestimmten Schwellenwerts liegt.For detecting the constant portion of the temperature profile, the control unit can in particular form a gradient of the temperature profile. The temperature profile can be classified as "substantially constant" if the gradient is below a certain threshold.

Eine Sicherheitsabschaltung kann gewährleistet werden, wenn die Steuereinheit dazu ausgelegt ist, den Betriebsmodus abzuschalten und ein Warnsignal zu erzeugen, wenn die von dem Temperatursensor erfasste Temperatur einen Maximalwert überschreitet. Dieser Maximalwert kann beispielsweise bei ca. 150° C liegen. Das Überschreiten des Maximalwerts deutet darauf hin, dass das Kochgeschirrelement leer ist, so dass ein Sieden nicht erfolgen kann.A safety shutdown can be ensured if the control unit is designed to switch off the operating mode and to generate a warning signal if the temperature detected by the temperature sensor exceeds a maximum value. For example, this maximum value may be around 150 ° C. Exceeding the maximum value indicates that the cookware element is empty so that boiling can not occur.

Ein weiterer Aspekt der Erfindung betrifft ein Verfahren zum Betreiben eines Kochfelds mit wenigstens einer Heizzone, einem Temperatursensor zum Detektieren der Temperatur eines auf die Heizzone aufgestellten Kochgeschirrelements und einer Steuereinheit. Es wird in zumindest einem Betriebsmodus das Kochgeschirrelement in einer Aufheizphase aufgeheizt und die Temperatur des Kochgeschirrelements wird in einer Haltephase auf eine Solltemperatur geregelt.A further aspect of the invention relates to a method for operating a hob with at least one heating zone, a temperature sensor for detecting the temperature a cookware element placed on the heating zone and a control unit. It is heated in at least one operating mode, the cookware element in a heating phase and the temperature of the cooking utensil element is controlled in a holding phase to a desired temperature.

Erfindungsgemäß wird vorgeschlagen, dass während der Aufheizphase eine Siedetemperatur der in dem Kochgeschirrelement enthaltenen Flüssigkeit detektiert wird und die Solltemperatur abhängig von der Siedetemperatur bestimmt wird.According to the invention, it is proposed that a boiling temperature of the liquid contained in the cookware element is detected during the heating phase and the setpoint temperature is determined as a function of the boiling temperature.

Weitere Vorteile und charakteristische Merkmale der Erfindung ergeben sich aus der folgenden Figurenbeschreibung. In den Figuren ist ein Ausführungsbeispiel der Erfindung dargestellt.Further advantages and characteristic features of the invention will become apparent from the following description of the figures. In the figures, an embodiment of the invention is shown.

Es zeigen:

Fig. 1
eine schematische Darstellung eines Induktionskochfelds mit einem Temperatursensor und einem auf einer Heizzone aufgestellten Kochgeschirrelement,
Fig. 2
die zeitlichen Verläufe einer Heizleistung, einer Wandtemperatur des Kochgeschirrelements und einer Garguttemperatur nach einem Ausführungsbeispiel der Erfindung, und
Fig. 3
ein Ablaufdiagramm eines Verfahrens zum Betreiben eines erfindungsgemäßen Kochfelds.
Show it:
Fig. 1
a schematic representation of an induction hob with a temperature sensor and a set up on a heating zone cookware element,
Fig. 2
the time courses of a heating power, a wall temperature of the cooking utensil element and a cooking temperature according to an embodiment of the invention, and
Fig. 3
a flow diagram of a method for operating a hob according to the invention.

Fig. 1 zeigt ein Kochfeld mit einer Heizzone 10, einem Temperatursensor 12 zum Detektieren der Wandtemperatur eines auf die Heizzone aufgestellten Kochgeschirrelements 14 und mit einer Steuereinheit 16. Die Heizzone 10 ist ein auf einer Abdeckplatte 18 des Kochfelds markierter Bereich, dessen Position und Größe der Position und Größe eines unterhalb der Abdeckplatte 18 angeordneten Induktors 20 entspricht. Das Kochfeld ist ein Induktionskochfeld und der Induktor 20 empfängt einen hochfrequenten Heizstrom von einem Wechselrichter 22. Zwischen einem Haushaltsstromnetz-Anschluss 34 und dem Wechselrichter 22 ist ein hier nicht dargestellter Gleichrichter angeordnet. Die Steuereinheit 16 bestimmt die Frequenz und/oder die Amplitude des von dem Wechselrichter 22 erzeugten Heizstroms so, dass im zeitlichen Mittel eine bestimmte Heizleistung erzeugt wird. Der Heizstrom erzeugt über den Induktor 20 ein hochfrequentes Wechselmagnetfeld, das seinerseits hochfrequente Wirbelströme im Boden des Kochgeschirrelements 14 erzeugt. Das Kochgeschirrelement 14 wird durch die Dissipation dieser Wirbelströme erhitzt. Fig. 1 shows a hob with a heating zone 10, a temperature sensor 12 for detecting the wall temperature of a set up on the heating zone cooking utensil 14 and a control unit 16. The heating zone 10 is a marked on a cover plate 18 of the hob, its position and size of the position and size an arranged below the cover 18 inductor 20 corresponds. The hob is an induction hob and the inductor 20 receives a high frequency heating current from an inverter 22. Between a household power grid connection 34 and the inverter 22, a rectifier, not shown here is arranged. The control unit 16 determines the frequency and / or the amplitude of the heating current generated by the inverter 22 so that a certain heating power is generated in the time average. The heating current generated via the inductor 20, a high-frequency alternating magnetic field, which in turn generates high-frequency eddy currents in the bottom of the cooking utensil element 14. The cookware element 14 is heated by the dissipation of these eddy currents.

Der Temperatursensor 12 ist ein turmartig über die Oberseite der Abdeckplatte 18 hinaus ragender Infrarot-Temperatursensor, welcher von einer Seitenwand des Kochgeschirrelements 14 emittierte Infrarotstrahlung detektiert. Das von dem Sensor 12 detektierte Signal wird von einer Sensor-Ausleseeinheit 24 verarbeitet und an die Steuereinheit 16 weitergeleitet. Die Sensor-Ausleseeinheit 24 kann beispielsweise eine Tiefpassfilterung und/oder eine Skalentransformation durchführen.The temperature sensor 12 is a tower-like above the top of the cover 18 also protruding infrared temperature sensor which detects infrared radiation emitted from a side wall of the cooking utensil element 14. The signal detected by the sensor 12 is processed by a sensor readout unit 24 and forwarded to the control unit 16. The sensor readout unit 24 may, for example, perform a low-pass filtering and / or a scale transformation.

Gegenüber der Abdeckplatte 18 in einem turmartigen Temperatursensor sind weitere Ausführungsbeispiele der Erfindung denkbar, in denen der Temperatursensor als unter der Abdeckplatte 18 angeordnetes NTC-Element oder als unter der Abdeckplatte angeordneter Infrarotsensor ausgebildet ist. Ferner ist es denkbar, den Temperatursensor 12 direkt an der Wand des Kochgeschirrelements 14 zu befestigen.Opposite the cover plate 18 in a tower-like temperature sensor further embodiments of the invention are conceivable in which the temperature sensor is formed as arranged under the cover plate 18 NTC element or arranged as the cover plate infrared sensor. Furthermore, it is conceivable to attach the temperature sensor 12 directly to the wall of the cookware element 14.

Die Steuereinheit 16 ist eine universell programmierbare Recheneinheit, die ein als Software implementiertes Verfahren zum Betreiben des Kochfelds ausführt. In dem Verfahren gibt es unterschiedliche Betriebsmodi. In einem speziellen Betriebsmodus, der auch als Simmermodus bezeichnet werden könnte, wird das Kochgeschirrelement 14 in einer Aufheizphase 26 aufgeheizt, bis eine Flüssigkeit 28 in dem Kochgeschirrelement 14 ihre Siedetemperatur TB erreicht.The control unit 16 is a universally programmable arithmetic unit that executes a software implemented method for operating the cooktop. There are different modes of operation in the method. In a particular operating mode, which could also be referred to as a simmer mode, the cookware element 14 is heated in a heating phase 26 until a liquid 28 in the cookware element 14 reaches its boiling temperature TB.

Die Steuereinheit 16 hält das Kochgeschirrelement 14 nur so lange auf der Siedetemperatur TB, bis diese mit einer hinreichenden Genauigkeit bestimmt worden ist. Anschließend schaltet die Steuereinheit 16 von der Aufheizphase 26 in eine Haltephase 32, in welcher die Temperatur des Kochgeschirrelements 14 bzw. der Flüssigkeit 28 auf eine Solltemperatur TS geregelt wird. Zum Bilden eines geschlossenen Regelkreises wird die Rückmeldung des Temperatursensors 12 verwendet.The control unit 16 holds the cookware element 14 only at the boiling temperature TB until it has been determined with sufficient accuracy. Subsequently, the control unit 16 switches from the heating phase 26 into a holding phase 32 in which the temperature of the cookware element 14 or of the liquid 28 is regulated to a desired temperature TS. To form a closed loop feedback from the temperature sensor 12 is used.

Der Zusammenhang zwischen der Temperatur der Flüssigkeit 28 und der Temperatur des Kochgeschirrelements 14 bzw. der Temperatur der radialen Außenwand des Kochgeschirrelements 14 kann über eine empirisch bestimmte Funktion ermittelt werden. In der Regel führen die Strahlungsverluste der Außenwand dazu, dass eine Proportionalität zwischen der Wandtemperatur des Kochgeschirrelements 14 und der Temperatur der Flüssigkeit 28 besteht, die durch einen konstanten Faktor ausgedrückt werden kann. Für die Erfindung ist es von nachrangiger Bedeutung, welchen Wert die Siedetemperatur TB der Flüssigkeit 28 selbst hat. Wesentlich ist die präzise Bestimmung der Außentemperatur des Kochgeschirrelements 14, die sich beim Erreichen der Siedetemperatur TB einstellt. Wegen der Proportionalität der beiden Temperaturen TB, TS können beide äquivalent verwendet werden.The relationship between the temperature of the liquid 28 and the temperature of the cooking utensil element 14 and the temperature of the radial outer wall of the cooking utensil element 14 can be determined via an empirically determined function. As a rule, the radiation losses of the outer wall result in a proportionality between the wall temperature of the cookware element 14 and the temperature of the liquid 28, which can be expressed by a constant factor. For the invention, it is of secondary importance which value the boiling temperature TB of the liquid 28 itself has. What is essential is the precise determination of the outside temperature of the cooking utensil element 14, which occurs when the boiling temperature TB is reached. Because of the proportionality of the two temperatures TB, TS both can be used equivalently.

Fig. 2 zeigt den zeitlichen Verlauf einer Heizleistung (durchgezogene Linie), die Temperatur der Flüssigkeit 28 (gestrichelte Linie) und die Temperatur der Wand des Kochgeschirrelements 14 (gepunktete Linie). Während der Aufheizphase 26 erreicht die Flüssigkeit 28 in einem Zeitpunkt t1 die Siedetemperatur TB und die Temperatur der Flüssigkeit 28 des Kochgeschirrelements 14 verläuft in einem Abschnitt 30 des Temperaturverlaufs im Wesentlichen konstant. Die Steuereinheit 16 mittelt die in diesem Abschnitt 30 von dem Temperatursensor 12 gemessene Temperatur und speichert diese Temperatur als die Siedetemperatur TB bzw. als die der Siedetemperatur zugeordnete Wandtemperatur des Kochgeschirrelements 14. In einem Zeitpunkt t2 schaltet die Steuereinheit 16 in die Haltephase 32, in welcher die Flüssigkeit 28 möglichst konstant auf einer Solltemperatur TS gehalten wird. Dies erfolgt in einem geschlossenen Regelkreis. Wenn beispielsweise in einem Zeitpunkt t3 zusätzliches Gargut oder zusätzliche Flüssigkeit 28 in das Kochgeschirrelement 14 gegeben wird, sinkt die Temperatur der Flüssigkeit kurzfristig ab, wird aber wieder auf die Solltemperatur TS erhöht. Wenn der Abfall der Temperatur zu groß ist, kann in einem Ausführungsbeispiel der Erfindung eine erneute Detektion der Siedetemperatur erfolgen, um möglicherweise einer geänderten Zusammensetzung der Flüssigkeit Rechnung zu tragen. Fig. 2 shows the time course of a heating power (solid line), the temperature of the liquid 28 (dashed line) and the temperature of the wall of the cookware element 14 (dotted line). During the heating phase 26, the liquid 28 reaches the boiling temperature TB at a time t1 and the temperature of the liquid 28 of the cooking utensil element 14 is substantially constant in a section 30 of the temperature profile. The control unit 16 averages the temperature measured in this section 30 by the temperature sensor 12 and stores this temperature as the boiling temperature TB or the boiling temperature associated wall temperature of the cookware element 14. At a time t2, the control unit 16 switches to the holding phase 32, in which the liquid 28 is kept as constant as possible at a desired temperature TS. This is done in a closed loop. If, for example, at a time t3 additional food or additional liquid 28 is added to the cookware element 14, the temperature of the liquid decreases briefly, but is increased again to the setpoint temperature TS. If the drop in temperature is too great, in one embodiment of the invention, a re-detection of the boiling temperature may take place to possibly accommodate a changed composition of the liquid.

Die Steuereinheit 16 bestimmt die Solltemperatur durch Subtraktion eines vorgegebenen gespeicherten Werts von der zuvor detektierten Siedetemperatur TB. Diese subtrahierte Temperaturdifferenz kann beispielsweise 5° C betragen, so dass sich für reines Wasser unter Standard-Atmosphärendruck eine Solltemperatur von 95° C ergibt. Bei 95° C werden Lebensmittel im Wesentlichen in der gleichen Weise gegart wie in sprudelnd kochendem Wasser mit 100° C, so dass Verdampfungsenergie eingespart werden kann, ohne den Garvorgang wesentlich zu beeinträchtigen.The control unit 16 determines the target temperature by subtracting a predetermined stored value from the previously detected boiling temperature TB. This subtracted temperature difference can be, for example, 5 ° C., so that a target temperature of 95 ° C. results for pure water under standard atmospheric pressure. Be at 95 ° C Food is cooked substantially in the same way as in bubbly boiling water at 100 ° C, so that evaporation energy can be saved without significantly affecting the cooking process.

Fig. 3 zeigt ein Ablaufdiagramm zur Durchführung des erfindungsgemäßen Verfahrens. In einem Schritt S1 wird der in der Abdeckplatte versenkbare Temperatursensor 12 aktiviert und aus seiner versenkten Stellung nach oben in eine Aktivierungsstellung gefahren. In einem Schritt S2 wird die Aufheizphase 26 gestartet. In einem Schritt S3 wird die Temperatur der Außenwand des Kochgeschirrelements 14 gemessen und in einem Schritt S4 aus dieser Temperatur durch Multiplikation mit einer Konstanten ein Schätzwert für die Temperatur der Flüssigkeit 28 ermittelt. In einem Schritt S5 beurteilt die Steuereinheit 16, ob die Flüssigkeit 28 kocht oder nicht. Dazu wertet die Steuereinheit 16 die nach den letzten Messungen aufgezeichnete Temperatur aus und überprüft, ob diese bis auf unvermeidliche Fluktuationen konstant ist. Ist dies der Fall, ist die Siedetemperatur TB erreicht. Falls nicht, springt das Verfahren in den Schritt S3 und nimmt eine erneute Messung vor. Wird in Schritt S5 eine Temperatur detektiert, die oberhalb einer Maximaltemperatur liegt, erfolgt eine Notabschaltung (nicht dargestellt). Fig. 3 shows a flowchart for carrying out the method according to the invention. In a step S1, the retractable in the cover plate temperature sensor 12 is activated and moved from its retracted position upwards into an activation position. In a step S2, the heating phase 26 is started. In a step S3, the temperature of the outer wall of the cooking utensil element 14 is measured and, in a step S4, an estimated value for the temperature of the liquid 28 is determined from this temperature by multiplying it by a constant. In a step S5, the control unit 16 judges whether the liquid 28 is boiling or not. For this purpose, the control unit 16 evaluates the temperature recorded after the last measurements and checks whether this is constant except for unavoidable fluctuations. If this is the case, the boiling temperature TB is reached. If not, the process jumps to step S3 and re-measures. If a temperature is detected in step S5 which is above a maximum temperature, an emergency shutdown occurs (not shown).

Wird in Schritt S5 das Erreichen der Siedetemperatur TB festgestellt, berechnet die Steuereinheit 16 in einem Schritt S6 die Solltemperatur TS für die Flüssigkeit 28 und schreitet in einem Schritt S7 in die Haltephase 32. In einem geschlossenen Regelkreis wird in einem Schritt S8 die Temperatur des Kochgeschirrelements 14 gemessen, in einem Schritt S9 aus der Temperatur des Kochgeschirrelements 14 die Temperatur der Flüssigkeit 28 berechnet und in einem Schritt S10 abhängig von dem Ergebnis die Heizleistung geregelt. Liegt die Temperatur des Flüssigkeit 28 über der Solltemperatur, wird die Heizleistung des Induktors 20 durch eine Variation der Frequenz des Wechselrichters 22 reduziert. Liegt die Temperatur unter der Solltemperatur TS, wird die Heizenergie des Induktors 20 erhöht. Nach dem Anpassen der Heizenergie springt das Verfahren zurück in den Schritt S8.If the boiling temperature TB is reached in step S5, the control unit 16 calculates the set temperature TS for the liquid 28 in a step S6 and goes to the holding phase 32 in a step S7. In a closed loop, the temperature of the cooking utensil element is determined in a step S8 14 measured, calculated in a step S9 from the temperature of the cooking utensil element 14, the temperature of the liquid 28 and regulated in step S10 depending on the result, the heating power. If the temperature of the liquid 28 is above the target temperature, the heating power of the inductor 20 is reduced by a variation of the frequency of the inverter 22. If the temperature is below the target temperature TS, the heating energy of the inductor 20 is increased. After adjusting the heating energy, the process returns to step S8.

Bezugszeichenreference numeral

1010
Heizzoneheating zone
1212
Temperatursensortemperature sensor
1414
KochgeschirrelementCookware element
1616
Steuereinheitcontrol unit
1818
Abdeckplattecover
2020
Induktorinductor
2222
Wechselrichterinverter
2424
Sensor-AusleseeinheitSensor readout unit
2626
Aufheizphaseheating phase
2828
Flüssigkeitliquid
3030
Abschnittsection
3232
Haltephaseholding phase
3434
Haushaltsstromnetz-AnschlussHousehold mains connection
TSTS
Solltemperaturset temperature
TBTB
Siedetemperaturboiling

Claims (7)

  1. Hob having at least one heating zone (10), a temperature sensor (12) for detecting the temperature of a cookware element (14) placed on the heating zone (10), and a control unit (16) for operating the heating zone (10), wherein the control unit (16) is designed so that in at least one operating mode it will heat up the cookware element (14) during a heating-up phase (26) and regulate the temperature of the cookware element (14) to a target temperature (TS) during a holding phase (32), characterised in that the control unit (16) is designed to detect a boiling point (TB) of the liquid (28) in the cookware element (14) during the heating-up phase (26) and determine the target temperature (TS) as a function of the boiling point (TB), wherein the control unit (16) records a temperature curve of the cookware element (14) during the heating-up phase (26), detects a substantially constant section (30) along the temperature curve, and detects the boiling point (TB) as an averaged temperature within the constant section (30).
  2. Hob according to claim 1, characterised in that the heating-up phase (26) lasts until a changeover instant (t2) after the boiling point (TB) has been reached.
  3. Hob according to one of the preceding claims, characterised in that the target temperature (TS) is a predefined temperature difference lower than the boiling point (TB).
  4. Hob according to claim 3, characterised in that the temperature difference is between 2°C and 7°C.
  5. Hob according to claim 1, characterised in that the control unit (16) forms a gradient of the temperature curve for detecting the constant section (30).
  6. Hob according to one of the preceding claims, characterised in that the control unit (16) is designed to deactivate the operating mode and produce a warning signal if the temperature registered by the temperature sensor (12) exceeds a maximum value.
  7. Method for operating a hob having at least one heating zone (10) and a temperature sensor (12) for detecting the temperature of a cookware element (14) placed on the heating zone (10), wherein, in at least one operating mode, the cookware element (14) is heated up during a heating-up phase (26) and the temperature of the cookware element (14) is regulated to a target temperature (TS) during a holding phase (32), characterised in that a boiling point (TB) of the liquid (28) in the cookware element (14) is detected during the heating-up phase (26) and the target temperature (TS) is determined as a function of the boiling point (TB), wherein in a step (S3), a temperature of an external wall of the cookware element (14) is measured and in a further step (S4) an estimated value for the temperature of the liquid (28) is determined from this temperature by multiplication with a constant.
EP10721505.5A 2009-06-01 2010-05-27 Hob comprising a temperature sensor Active EP2438796B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ES200930236A ES2368643B1 (en) 2009-06-01 2009-06-01 COOKING FIELD WITH A TEMPERATURE SENSOR.
PCT/EP2010/057323 WO2010139598A1 (en) 2009-06-01 2010-05-27 Hob having a temperature sensor

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EP2438796A1 EP2438796A1 (en) 2012-04-11
EP2438796B1 true EP2438796B1 (en) 2019-11-06

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CN102450094A (en) 2012-05-09
US20120168425A1 (en) 2012-07-05
EP2438796A1 (en) 2012-04-11
WO2010139598A1 (en) 2010-12-09
US8530798B2 (en) 2013-09-10
ES2368643B1 (en) 2012-10-10
ES2368643A1 (en) 2011-11-21

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