WO2000057760A1 - Electronically controlled liquid-heating domestic electrical appliance - Google Patents
Electronically controlled liquid-heating domestic electrical appliance Download PDFInfo
- Publication number
- WO2000057760A1 WO2000057760A1 PCT/FR2000/000810 FR0000810W WO0057760A1 WO 2000057760 A1 WO2000057760 A1 WO 2000057760A1 FR 0000810 W FR0000810 W FR 0000810W WO 0057760 A1 WO0057760 A1 WO 0057760A1
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- WO
- WIPO (PCT)
- Prior art keywords
- electrical appliance
- household electrical
- insulating plate
- appliance according
- thermistor
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Classifications
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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
- H05B1/0227—Applications
- H05B1/0252—Domestic applications
- H05B1/0258—For cooking
- H05B1/0269—For heating of fluids
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- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
- A47J27/00—Cooking-vessels
- A47J27/21—Water-boiling vessels, e.g. kettles
- A47J27/21008—Water-boiling vessels, e.g. kettles electrically heated
- A47J27/21041—Water-boiling vessels, e.g. kettles electrically heated with heating elements arranged outside the water vessel
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- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
- A47J27/00—Cooking-vessels
- A47J27/21—Water-boiling vessels, e.g. kettles
- A47J27/21008—Water-boiling vessels, e.g. kettles electrically heated
- A47J27/21058—Control devices to avoid overheating, i.e. "dry" boiling, or to detect boiling of the water
- A47J27/21091—Control devices to avoid overheating, i.e. "dry" boiling, or to detect boiling of the water of electronic type
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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
- H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
- H05B2203/02—Heaters using heating elements having a positive temperature coefficient
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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
- H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
- H05B2203/021—Heaters specially adapted for heating liquids
Definitions
- the invention relates to an electrical household appliance with liquid heating comprising a reservoir intended to contain the liquid to be heated, a screen printing heating element having at least one resistive track formed on an electrically insulating plate secured to a metal support, and a system for control of the electrical supply to the heating element.
- the invention relates to household appliances of the electric kettle or fryer type.
- the devices known in this field are generally equipped with electrical supply cut-off systems, which react to the exceeding of a temperature threshold.
- the temperature detection and the shutdown of the heating element supply circuit are carried out by an element of the bimetallic thermostat type placed in contact with the insulating plate and the resistive track, or by a temperature detector arranged in a internal part of the device not Deigned with liquid, so as to react to the presence of steam generated in the device.
- abnormal operating situations include, for example, cases where the liquid reservoir is empty or contains a very small amount of liquid, or the device is tilted from its normal operating position and contains a small amount of liquid, so that
- CONFIRMED COPY the elemert cnaaffant is partially discovered, or in the case where the bottom of the apparatus is excessive ⁇ ment entartre.
- the power cut occurs late after the start of abnormal operation or a boiling pnase
- the boiling point is not detected if the device is used under an ambient pressure lower than that intended for the most common uses, for example in the case of uses at altitude;
- the main object of the invention is to remedy the above drawbacks, that is to say to produce an electrical device for the supply of liquid of the type described above which ensures very rapid cut-off of the electrical supply to the heating element from the appearance of an abnormal operating phase, or as soon as the boiling temperature of the liquid is reached.
- control system includes a thermistor, fixed on the insulating plate in the vicinity of the resistive track, the resistance of which varies as a function of temperature variations of the resistive track and the plate. - that insulating.
- the very slight thermal inertia to such a component gives almost real-time access to significant information on the temperature of the liquid, or on abnormal operation of the device.
- FIG. 1 is a schematic representation in elevation of an apparatus according to the invention
- FIG. 2 is a perspective view of a heating element used in an apparatus according to the invention.
- an electrical household appliance 1 for heating liquid more specifically a kettle, comprising a reservoir 2 intended to contain the liquid 3 to be heated, a heating element 4, and a control system 5 of the power supply to the heating element 4.
- the heating element 4 is a screen-printed type heating element having at least one resistive track 6 formed on an electrically insulating and good thermal conductor plate 7.
- the plate 7 may consist of a set of layers of enameled or vitrified materials.
- the insulating plate 7 is secured to a metal support 8, preferably made of stainless steel, which takes the shape of a cup and constitutes the bottom 9 of the tank 2, so that the insulating plate 7 and the cup 8 are in contact thermal and that the resistive track 6 is electrically isolated from said cup 8. ⁇
- control system 5 comprises a thermistor 10, fixed on the insulating plate 7 in the vicinity of the resistive track 6, tooth the resistance varies as a function of temperature variations of the resistive track 6 and of the insulating plate 7 .
- the resistive track 6 extends on one of the two faces 11, 12 of the insulating plate 7, the thermistor 10 being mounted on the surface on the same face 11 of the insulating plate 7; this type of mounting of components is known in the field of printed circuits under the name CMS.
- the thermistor 10 is of the resistance type with a negative temperature coefficient, called “CTN”.
- the control system 5 comprises a switching element, for example a t ⁇ ac, mounted on the surface on the insulating plate 7. Said switching element is controlled by a control signal dependent on the resistance value of the thermistor 10, and performs in response the opening or closing of the heating element supply circuit 4.
- a switching element for example a t ⁇ ac
- a component of the t ⁇ ac type is perfectly suited to the application, having regard in particular to the criteria of size, resistance to temperature and cost.
- the control system 5 also includes an electronic device, which can be analog or digital, for controlling the switching element, and which generates a signal for controlling the switching element from a first signal representative of the resistance value of the thermistor 10.
- an electronic device which can be analog or digital, for controlling the switching element, and which generates a signal for controlling the switching element from a first signal representative of the resistance value of the thermistor 10.
- the control system includes a t ⁇ ac corn- 0 controlled by a transistor or an operational amplifier, these components being surface mounted on the insulating plate 7.
- the control system also includes a controlled t ⁇ ac, this time, by a microcontroller, these components being mounted on the surface on the insulating plate 7.
- the CMS technology thus applied makes it possible to associate, in a very small footprint, the heating element 4 and the control and command electronics, the whole being defined as a single module requiring no additional wiring and connectors, which are a source of potential failure for this type of electrical appliance.
- FIG. 1 shows the assembly consisting of the cup 8 and the insulating plate 7 in a configuration seen from below, the cup 8 being mounted in the apparatus 1 so that its internal face is in contact with the liquid 3 placed in the tank 2.
- control system 5 also comprises means for adjusting, not shown, a set value, which can be simply of the switch type with two on / off states or, more advanced, either of the potentiometer type for setting a set temperature, or of the selector type for selecting an operating mode; these adjustment means deliver a second signal representative of the set value, and develop, from the first and second o signals, the control signal that the switching element.
- the apparatus comprises a selector whose position corresponds to a boiling mode with maintaining the temperature of the liquid.
- the invention also provides that the electronic control unit 13 generates a warning signal from the first and second signals, representing respectively the state of the thermistor or CTN 10, and the setpoint.
- This warning signal is intended to be used by audible means and / or display means.
- the apparatus 1 comprises sound generation members controlled by the warning signal, and / or light display members, such as a display or indicator lights, also controlled by the warning signal.
- the apparatus according to the invention is provided with a safety system acting on the resistance values of the thermistor 10, the variations of said values being significant of normal or abnormal operating states of the apparatus.
- a rapid change in the resistance value of the thermistor 10 indicates rapid heating of the insulating plate 7 and the resistive track 6, a phenomenon which can be explained by scaling. excessive heat exchange surface between the heating element 4 and the liquid 3; through the absence or insufficiency of liquid; or by an excessive inclination of the device doubled by an insufficient quantity of liquid, which has the effect of leaving a part of the heating element above the level of the liquid.
- the invention provides that the control signal of the switching element is a cut-off signal, since, over a predetermined time interval, the variation of the resistance value of thermistor 10 exceeds a predetermined threshold value.
- the microcontroller 13 emits for example a stop signal or a sequence of stop and restart signals to maintain the liquid at temperature.
- a thermistor in particular of the CTN type, as a detection means, makes it possible to obtain a very high speed in the interpretation of a case of abnormal functioning or boiling, this thanks to the low thermal inertia of the component as has already been mentioned, and to the short duration of the time interval necessary for the discrimination of such cases: typically, the safety cut-off intervening to put an end to abnormal operation of the device can be performed 3 to 4 seconds after the actual appearance of the phenomenon.
- the reaction time of the system thus defined is considerably reduced compared to known security systems, with the consequence of increased reliability of the device.
- the invention allows for such appliances kettles or fryers, which presen ⁇ tent not only improved reliability and security, but also a greater diversity of generating functions of a great facility and great flexibility of use.
Landscapes
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Frying-Pans Or Fryers (AREA)
- Cookers (AREA)
- Apparatus For Making Beverages (AREA)
Abstract
Description
APPAREIL ELECTRIQUE MENAGER DE CHAUFFAGE DE LIQUIDE CONTROLE ELECTRONIQUEMENT ELECTRICALLY CONTROLLED LIQUID HEATING ELECTRIC HOUSEHOLD APPLIANCE
L'invention concerne un appareil électrique ménager αe cnauffage αe liquide comportant an réservoir destine a contenir le liquide a chauffer, un élément cnauffant sérigraphie présentant au moins αne piste résistive formée sur une plaque électriquement isolante solidaire d' un support métallique, et un système de contrôle de l'alimentation électrique de l' élément chauffant.The invention relates to an electrical household appliance with liquid heating comprising a reservoir intended to contain the liquid to be heated, a screen printing heating element having at least one resistive track formed on an electrically insulating plate secured to a metal support, and a system for control of the electrical supply to the heating element.
En particulier, l'invention se rapporte a des appareils ménagers du type bouilloires ou friteuses électriques .In particular, the invention relates to household appliances of the electric kettle or fryer type.
Les appareils connus dans ce domaine sont généralement équipes de systèmes de coupure d' alimentation électrique, qui réagissent au dépassement d'un seuil de température. La détection de la température et la coupure du circuit d'alimentation de l'élément chauffant sont réalisées par un élément du type thermostat bimétallique place au contact de la plaque isolante et de la piste résistive, ou encore par un détecteur de température dispose dans une partie interne de l'appareil non Daignée par le liquide, de manière a reagir a la présence de vapeur générée dans l'appareil.The devices known in this field are generally equipped with electrical supply cut-off systems, which react to the exceeding of a temperature threshold. The temperature detection and the shutdown of the heating element supply circuit are carried out by an element of the bimetallic thermostat type placed in contact with the insulating plate and the resistive track, or by a temperature detector arranged in a internal part of the device not Deigned with liquid, so as to react to the presence of steam generated in the device.
Ces systèmes de détection présentent une série d'inconvénients, qui tous, peuvent conduire a une dete- rioration prématurée de l'appareil en cas d'utilisations anormales répétées. Les situations de fonctionnement dites anormales, comprennent par exemple les cas ou le réservoir de liquide est vide ou contient une très faible quantité de liquide, ou l'appareil est incline par rap- port a sa position normale de fonctionnement et contient une faible quantité de liquide, de telle sorte queThese detection systems have a series of drawbacks, all of which can lead to premature deterioration of the device in the event of repeated abnormal use. So-called abnormal operating situations include, for example, cases where the liquid reservoir is empty or contains a very small amount of liquid, or the device is tilted from its normal operating position and contains a small amount of liquid, so that
COPIE DE CONFIRMAI l'elemert cnaaffant soit partiellement découvert , ou encore dans le cas ou le fond de l'appare_l est excessive¬ ment entartre.CONFIRMED COPY the elemert cnaaffant is partially discovered, or in the case where the bottom of the apparatus is excessive ¬ ment entartre.
On peut notamment citer les inconvénients suivants, comme insuffisances des techniques connues pour le type d'appareils vises par l'invention :Mention may in particular be made of the following drawbacks, as inadequacies of the techniques known for the type of apparatus covered by the invention:
- compte tenu de l'inertie tnermique relativement importante des thermostats bimetalliαues utilises couramment, la coupure d'alimentation intervient tardivement après le début d'un fonctionnement anormal ou d'une pnase d'ebullition ;- given the relatively large thermal inertia of bimetalliαues thermostats commonly used, the power cut occurs late after the start of abnormal operation or a boiling pnase;
- la pnase d' ebullition n'est pas détectée si l'appareil est utilise sous une pression ambiante inférieure a celle prévue pour les utilisations les plus cou- rantes, par exemple dans le cas d'utilisations en altitude ;- the boiling point is not detected if the device is used under an ambient pressure lower than that intended for the most common uses, for example in the case of uses at altitude;
- dans le cas de détecteurs de vapeur, le système de coupure fonctionne mal ou ne fonctionne pas des lors que le couvercle de l'appareil n'est pas en place.- in the case of steam detectors, the cut-off system malfunctions or does not work as soon as the appliance cover is not in place.
L'invention a pour principal obi et de remédier aux inconvénients ci-dessus, c'est-à-dire de réaliser un appareil électrique de cnauffage de liquide du type décrit précédemment qui assure une coupure très rapide de l'alimentation électrique de l'élément chauffant des l'apparition d'une phase de fonctionnement anormal, ou des que la température d' ebullition du liquide est atteinte .The main object of the invention is to remedy the above drawbacks, that is to say to produce an electrical device for the supply of liquid of the type described above which ensures very rapid cut-off of the electrical supply to the heating element from the appearance of an abnormal operating phase, or as soon as the boiling temperature of the liquid is reached.
Ces buts sont atteints par l'invention, qui dispose que le système de contrôle comporte une thermistance, fixée sur la plaque isolante au voisinage de la piste résistive, dont la résistance varie en fonction des variations de température de la piste résistive et de la pla- que isolante. La très faiole inertie thermique α' un tel composant donne un accès quasiment en temps réel a une information significative de la température du liquide, ou d'un fonctionnement anormal de l'appareil.These objects are achieved by the invention, which provides that the control system includes a thermistor, fixed on the insulating plate in the vicinity of the resistive track, the resistance of which varies as a function of temperature variations of the resistive track and the plate. - that insulating. The very slight thermal inertia to such a component gives almost real-time access to significant information on the temperature of the liquid, or on abnormal operation of the device.
D'autres caractéristiques et avantages de l'invention ressortiront de la description qui va suivre, donnée a titre d'exemple non limitatif, en référence aux dessins annexes dans lesquels:Other characteristics and advantages of the invention will emerge from the description which follows, given by way of nonlimiting example, with reference to the accompanying drawings in which:
- la figure 1 est une représentation scnématique en élévation d'un appareil suivant l'invention ;- Figure 1 is a schematic representation in elevation of an apparatus according to the invention;
- la figure 2 est une vue en perspective d'un élément chauffant utilise dans un appareil suivant l' invention .- Figure 2 is a perspective view of a heating element used in an apparatus according to the invention.
A la figure 1, on a représenté un appareil électrique ménager 1 de chauffage de liquide, plus précisément une bouilloire, comportant un réservoir 2 destiné à con- tenir le liquide 3 à chauffer, un élément chauffant 4, et un système de contrôle 5 de l'alimentation électrique de l'élément chauffant 4.In Figure 1, there is shown an electrical household appliance 1 for heating liquid, more specifically a kettle, comprising a reservoir 2 intended to contain the liquid 3 to be heated, a heating element 4, and a control system 5 of the power supply to the heating element 4.
Comme représenté a la figure 2, l'élément chauffant 4 est un élément chauffant de type sérigraphié présentant au moins une piste résistive 6 formée sur une plaque 7 électriquement isolante et bonne conductrice thermique. Par exemple, la plaque 7 peut être constituée d'un ensemble de couches de matières émaillées ou vitrifiées. La plaque isolante 7 est solidaire d' un support métallique 8, de préférence en acier inoxydable, qui affecte la forme d'une coupelle et constitue le fond 9 du réservoir 2, de façon que la plaque isolante 7 et la coupelle 8 soient en contact thermique et que la piste résistive 6 soit électriquement isolée de ladite coupelle 8. ΔAs shown in FIG. 2, the heating element 4 is a screen-printed type heating element having at least one resistive track 6 formed on an electrically insulating and good thermal conductor plate 7. For example, the plate 7 may consist of a set of layers of enameled or vitrified materials. The insulating plate 7 is secured to a metal support 8, preferably made of stainless steel, which takes the shape of a cup and constitutes the bottom 9 of the tank 2, so that the insulating plate 7 and the cup 8 are in contact thermal and that the resistive track 6 is electrically isolated from said cup 8. Δ
Suivant l'invention, le système de contrôle 5 comporte une thermistance 10, fixée sur la p_aque isolante 7 au voisinage de la piste résistive 6, dent la résistance varie en fonction des variations de température de la piste résistive 6 et de la plaque isolante 7.According to the invention, the control system 5 comprises a thermistor 10, fixed on the insulating plate 7 in the vicinity of the resistive track 6, tooth the resistance varies as a function of temperature variations of the resistive track 6 and of the insulating plate 7 .
En particulier, la piste résistive 6 s'étend sur l'une des deux faces il, 12 de la plaque isolante 7, la thermistance 10 étant montée en surface sur la même face 11 de la plaque isolante 7 ; ce type de montage de composants est connu dans le domaine des circuits imprimes sous l'appellation CMS.In particular, the resistive track 6 extends on one of the two faces 11, 12 of the insulating plate 7, the thermistor 10 being mounted on the surface on the same face 11 of the insulating plate 7; this type of mounting of components is known in the field of printed circuits under the name CMS.
Selon une caractéristique intéressante de l'invention, la thermistance 10 est de type résistance à coefficient de température négatif, appelée « CTN ».According to an advantageous characteristic of the invention, the thermistor 10 is of the resistance type with a negative temperature coefficient, called “CTN”.
Le système de contrôle 5 comporte un élément de commutation, par exemple un tπac, monte en surface sur la plaque isolante 7. Ledit élément de commutation est commandé par un signal de commande dépendant de la valeur de résistance de la thermistance 10, et réalise en réponse l'ouverture ou la fermeture du circuit d'alimentation de l'élément chauffant 4. Un composant du type tπac est parfaitement adapte à l'application, eu égard notamment aux critères d'encombrement, de tenue à la température et de coût.The control system 5 comprises a switching element, for example a tπac, mounted on the surface on the insulating plate 7. Said switching element is controlled by a control signal dependent on the resistance value of the thermistor 10, and performs in response the opening or closing of the heating element supply circuit 4. A component of the tπac type is perfectly suited to the application, having regard in particular to the criteria of size, resistance to temperature and cost.
Le système de contrôle 5 comporte également un or- gane électronique, qui peut être a fonctionnement analogique ou numérique, de commande de l'élément de commutation, et qui élabore un signal de commande de l'élément de commutation à partir d'un premier signal représentatif de la valeur de résistance de la thermistance 10. Dans le cas d'une électronique analogique, on peut prévoir par exemple que le système de contrôle comporte un tπac corn- 0 mande par un transistor ou un amplificateur opérationnel, ces composants étant montes en surface sur la plaque isolante 7. Alternativement, dans le cas d'une électronique numérique, on peut prévoir que le système de contrôle comporte également un tπac commandé, cette fois, par un microcontrôleur, ces composants étant montés en surface sur la plaque isolante 7.The control system 5 also includes an electronic device, which can be analog or digital, for controlling the switching element, and which generates a signal for controlling the switching element from a first signal representative of the resistance value of the thermistor 10. In the case of analog electronics, provision may be made for example that the control system includes a tπac corn- 0 controlled by a transistor or an operational amplifier, these components being surface mounted on the insulating plate 7. Alternatively, in the case of digital electronics, it can be provided that the control system also includes a controlled tπac, this time, by a microcontroller, these components being mounted on the surface on the insulating plate 7.
La technologie CMS ainsi appliquée, permet d'associer dans un encombrement très réduit l'élément chauffant 4 et l'électronique de contrôle et de commande, l'ensemble se définissant comme un module unique ne nécessitant pas de câblage et de connectique supplémentaires, qui sont une source de défaillance potentielle de ce type d'appareils électriques.The CMS technology thus applied makes it possible to associate, in a very small footprint, the heating element 4 and the control and command electronics, the whole being defined as a single module requiring no additional wiring and connectors, which are a source of potential failure for this type of electrical appliance.
La face 12 de la plaque isolante 7 qui coïncide avec la face externe du support métallique 8 en forme de coupelle est opposée à celle sur laquelle sont disposés la piste résistive 6 et les composants électroniques. La figure 2 présente l'ensemble constitué de la coupelle 8 et de la plaque isolante 7 dans une configuration vue de dessous, la coupelle 8 étant montée dans l'appareil 1 de façon que sa face interne soit au contact du liquide 3 placé dans le réservoir 2.The face 12 of the insulating plate 7 which coincides with the external face of the metal support 8 in the form of a cup is opposite to that on which the resistive track 6 and the electronic components are arranged. Figure 2 shows the assembly consisting of the cup 8 and the insulating plate 7 in a configuration seen from below, the cup 8 being mounted in the apparatus 1 so that its internal face is in contact with the liquid 3 placed in the tank 2.
Suivant une réalisation privilégiée de l'invention, le système de contrôle 5 comporte en outre des moyens de réglage, non représentés, d'une valeur de consigne, qui peuvent être simplement du type interrupteur a deux états marcne / arrêt ou, de manière plus évoluée, soit du type potentiomètre permettant de régler une température de consigne, soit de type sélecteur permettant de sélectionner un mode de fonctionnement ; ces moyens de réglage dé- livrent un deuxième signal représentatif de la valeur de consigne, et élaborent, à partir des premier et deuxième o signaux, le signal de commande ce l'élément de commutation.According to a preferred embodiment of the invention, the control system 5 also comprises means for adjusting, not shown, a set value, which can be simply of the switch type with two on / off states or, more advanced, either of the potentiometer type for setting a set temperature, or of the selector type for selecting an operating mode; these adjustment means deliver a second signal representative of the set value, and develop, from the first and second o signals, the control signal that the switching element.
On peut ainsi prévoir, par exemple, que l'appareil comporte un sélecteur dont une position corresponde a un mode d'ébullition avec maintien en température du liquideWe can thus provide, for example, that the apparatus comprises a selector whose position corresponds to a boiling mode with maintaining the temperature of the liquid.
3, par réactivation cyclique de l'élément chauffant à jusqu'au passage a une position d'arrêt.3, by cyclic reactivation of the heating element until passing to a stop position.
L'invention prévoit également que l'organe électronique de commande 13 élabore un signal d'avertissement à partir des premier et deuxième signaux, représentant respectivement l'état de la thermistance ou CTN 10, et la consigne .The invention also provides that the electronic control unit 13 generates a warning signal from the first and second signals, representing respectively the state of the thermistor or CTN 10, and the setpoint.
Ce signal d'avertissement est destiné a être exploité par des moyens sonores et/ou des moyens de visualisation.This warning signal is intended to be used by audible means and / or display means.
A cette fin, l'appareil 1 comporte des organes de génération sonore commandés par le signal d'avertissement, et/ou des organes lumineux de visualisation, comme un afficheur ou des témoins lumineux, également commandés par le signal d'avertissement.To this end, the apparatus 1 comprises sound generation members controlled by the warning signal, and / or light display members, such as a display or indicator lights, also controlled by the warning signal.
L'appareil suivant l'invention est pourvu d'un système de sécurité agissant à partir des valeurs de résistance de la thermistance 10, les variations desdites valeurs étant significatives d' états de fonctionnement nor- maux ou anormaux de l'appareil. En effet, après la mise en marche de l'appareil, une variation rapide de la valeur de résistance de la thermistance 10 traduit un échauffement rapide de la plaque isolante 7 et de la piste résistive 6, phénomène qui peut s'expliquer par un entartrage excessif de la surface d'échange de chaleur entre l'élément chauffant 4 et le liquide 3 ; par l'absence ou l'insuffisance de liquide ; ou encore par une inclinaison excessive de l'appareil doublée d'une quantité de liquide insuffisante, ce qui a pour effet de laisser une partie αe l'élément chauffant à au-dessus du niveau du liquide.The apparatus according to the invention is provided with a safety system acting on the resistance values of the thermistor 10, the variations of said values being significant of normal or abnormal operating states of the apparatus. In fact, after switching on the device, a rapid change in the resistance value of the thermistor 10 indicates rapid heating of the insulating plate 7 and the resistive track 6, a phenomenon which can be explained by scaling. excessive heat exchange surface between the heating element 4 and the liquid 3; through the absence or insufficiency of liquid; or by an excessive inclination of the device doubled by an insufficient quantity of liquid, which has the effect of leaving a part of the heating element above the level of the liquid.
Pour mettre fin a un fonctionnement anormal du type précité, l'invention dispose que le signal de commande de l'élément de commutation est un signal de coupure, dès lors que, sur un intervalle de temps prédétermine, la variation de la valeur de résistance de la thermistance 10 dépasse une valeur de seuil prédéterminée.To end an abnormal operation of the aforementioned type, the invention provides that the control signal of the switching element is a cut-off signal, since, over a predetermined time interval, the variation of the resistance value of thermistor 10 exceeds a predetermined threshold value.
L'arrivée de la valeur de résistance de la thermis- tance 10 à un pallier est, elle, significative de l'ébullition du liquide. Dans ce cas, suivant le mode sélectionné par l'utilisateur, le microcontrôleur 13 émet par exemple un signal d'arrêt ou une séquence de signaux d'arrêt et de remise en marche pour maintien du liquide à température.The arrival of the resistance value of the thermistor 10 at a level is itself significant of the boiling of the liquid. In this case, according to the mode selected by the user, the microcontroller 13 emits for example a stop signal or a sequence of stop and restart signals to maintain the liquid at temperature.
Il est important de noter que l'emploi d'une thermistance, en particulier de type CTN, comme moyen de détection, permet d'obtenir une très grande rapidité dans l'interprétation d'un cas de fonctionnement anormal ou d' ébullition, ce grâce à la faible inertie thermique du composant comme cela a dé] à été mentionné, et à la faible durée de l'intervalle de temps nécessaire à la discrimination de tels cas : typiquement, la coupure de sécurité intervenant pour mettre fin à un fonctionnement anormal de l'appareil peut être réalisée de 3 à 4 secondes après l'apparition réelle du phénomène. Le temps de réaction du système ainsi défini est considérablement réduit par rapport aux systèmes de sécurité connus, avec pour consé- quence une fiabilité accrue de l'appareil. L'invention permet de réaliser des appareils électroménagers de type bouilloires ou friteuses, qui présen¬ tent non seulement une fiabilité et une sécurité accrues, mais également une plus grande diversité de fonctions génératrice d'une grande facilite et d'une grande souplesse d' utilisation. It is important to note that the use of a thermistor, in particular of the CTN type, as a detection means, makes it possible to obtain a very high speed in the interpretation of a case of abnormal functioning or boiling, this thanks to the low thermal inertia of the component as has already been mentioned, and to the short duration of the time interval necessary for the discrimination of such cases: typically, the safety cut-off intervening to put an end to abnormal operation of the device can be performed 3 to 4 seconds after the actual appearance of the phenomenon. The reaction time of the system thus defined is considerably reduced compared to known security systems, with the consequence of increased reliability of the device. The invention allows for such appliances kettles or fryers, which presen ¬ tent not only improved reliability and security, but also a greater diversity of generating functions of a great facility and great flexibility of use.
Claims
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR99/03999 | 1999-03-30 | ||
| FR9903999A FR2791857B1 (en) | 1999-03-30 | 1999-03-30 | ELECTRICALLY CONTROLLED LIQUID HEATING ELECTRIC HOUSEHOLD APPLIANCE |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2000057760A1 true WO2000057760A1 (en) | 2000-10-05 |
Family
ID=9543837
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/FR2000/000810 Ceased WO2000057760A1 (en) | 1999-03-30 | 2000-03-30 | Electronically controlled liquid-heating domestic electrical appliance |
Country Status (2)
| Country | Link |
|---|---|
| FR (1) | FR2791857B1 (en) |
| WO (1) | WO2000057760A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2901955B1 (en) * | 2006-06-05 | 2010-03-26 | Seb Sa | HOUSEHOLD APPLIANCE FOR LIQUID HEATING |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0380369A1 (en) * | 1989-01-26 | 1990-08-01 | Otter Controls Limited | Controls for electrically powered heating elements |
| EP0585015A1 (en) * | 1992-08-13 | 1994-03-02 | Pifco Limited | Apparatus for heating liquid |
| WO1996025869A1 (en) * | 1995-02-20 | 1996-08-29 | Pifco Limited | Improvements to liquid boiling apparatus |
| WO1998054931A1 (en) * | 1997-05-29 | 1998-12-03 | Koninklijke Philips Electronics N.V. | Heating element |
| FR2774186A1 (en) * | 1998-01-28 | 1999-07-30 | Seb Sa | Thermostat with thermistor and relay switch for electric heating elements in domestic appliances |
-
1999
- 1999-03-30 FR FR9903999A patent/FR2791857B1/en not_active Expired - Fee Related
-
2000
- 2000-03-30 WO PCT/FR2000/000810 patent/WO2000057760A1/en not_active Ceased
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0380369A1 (en) * | 1989-01-26 | 1990-08-01 | Otter Controls Limited | Controls for electrically powered heating elements |
| EP0585015A1 (en) * | 1992-08-13 | 1994-03-02 | Pifco Limited | Apparatus for heating liquid |
| WO1996025869A1 (en) * | 1995-02-20 | 1996-08-29 | Pifco Limited | Improvements to liquid boiling apparatus |
| WO1998054931A1 (en) * | 1997-05-29 | 1998-12-03 | Koninklijke Philips Electronics N.V. | Heating element |
| FR2774186A1 (en) * | 1998-01-28 | 1999-07-30 | Seb Sa | Thermostat with thermistor and relay switch for electric heating elements in domestic appliances |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2791857B1 (en) | 2002-04-19 |
| FR2791857A1 (en) | 2000-10-06 |
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