EP2872831A1 - A device and a method for reducing the temperature of a cooking device - Google Patents
A device and a method for reducing the temperature of a cooking deviceInfo
- Publication number
- EP2872831A1 EP2872831A1 EP20130817618 EP13817618A EP2872831A1 EP 2872831 A1 EP2872831 A1 EP 2872831A1 EP 20130817618 EP20130817618 EP 20130817618 EP 13817618 A EP13817618 A EP 13817618A EP 2872831 A1 EP2872831 A1 EP 2872831A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- temperature
- hot plate
- cooking
- reducing device
- control system
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24C—DOMESTIC STOVES OR RANGES ; DETAILS OF DOMESTIC STOVES OR RANGES, OF GENERAL APPLICATION
- F24C7/00—Stoves or ranges heated by electric energy
- F24C7/08—Arrangement or mounting of control or safety devices
- F24C7/087—Arrangement or mounting of control or safety devices of electric circuits regulating heat
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24C—DOMESTIC STOVES OR RANGES ; DETAILS OF DOMESTIC STOVES OR RANGES, OF GENERAL APPLICATION
- F24C7/00—Stoves or ranges heated by electric energy
- F24C7/08—Arrangement or mounting of control or safety devices
- F24C7/082—Arrangement or mounting of control or safety devices on ranges, e.g. control panels, illumination
- F24C7/083—Arrangement or mounting of control or safety devices on ranges, e.g. control panels, illumination on tops, hot plates
-
- 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
- H05B1/0261—For cooking of food
- H05B1/0266—Cooktops
-
- 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
- H05B3/00—Ohmic-resistance heating
- H05B3/68—Heating arrangements specially adapted for cooking plates or analogous hot-plates
- H05B3/74—Non-metallic plates, e.g. vitroceramic, ceramic or glassceramic hobs, also including power or control circuits
- H05B3/746—Protection, e.g. overheat cutoff, hot plate indicator
-
- 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 present invention relates to a temperature reducing device for reducing the temperature of at least one hot plate of a cooking device in the form of a cooking stove or a cooking top.
- the present invention also relates to a method for reducing the temperature of at least one hot plate of a cooking device.
- the invention is especially directed to such a device and method used in conjunction with the kind of cooking device comprising hot plates with heating elements mounted under a glass ceramic surface.
- a cooking device can heat a cooking utensil with e.g . oil or other fatty substances to such a temperature that the contents catch fire, which may resu lt in a domestic fire .
- the autoignition temperature for ordinary cooking oil is typically between 350°C and 400°C and a normal cooking temperature is typically around or under 200°C .
- There are a number of techniques to prevent domestic fires in conjunction with cooking e.g . so called stove guards which turn the cooking device off based on measurements of outer criteria. It may be for example that the temperature of the cooking utensils exceeds a certain value, that smoke is detected in the vicinity of the cooking device or that no person is detected in the vicin ity of the cooking device.
- a temperature reducing device for reducing the temperature of a cooking stove is disclosed in JP2008300182.
- the temperature reducing device comprises a sensor for sensing the presence of a person in the vicinity of the stove, a control system and a temperature sensor for sensing the temperature of a hot plate of the stove. If no person is detected near the stove during a predetermined time and if the temperature of the hot plate exceeds a threshold value, the power supplied to the stove is adjusted so that the temperature of the hot plate is reduced .
- the temperature reducing device accord ing to claim 1 .
- at least some of these objects are achieved by a method for reducing the temperature of at least one hot plate of a cooking device in the form of a cooking stove or a cooking top according to the independent claim 13.
- the temperature reducing device according to the invention has the advantage that it does not rely on internal or external temperature sensors in order to adjust the temperature of a hot plate of a cooking device.
- the temperature reducing device accord ing to the invention is instead configured to determine whether a threshold temperature is exceeded and , if no person is present in the vicin ity of the cooking device, to adjust the temperature of the hot plate based on pulse characteristics of a pulsed voltage supplied to the hot plate. This makes the temperature reducing device easier to mount onto a cooking device after installation of the cooking device than devices comprising internal or external temperature sensors for sensing the temperature of a hot plate.
- the control system is configured to continuously calcu late the temperature of said at least one hot plate over time using said pulse characteristics and a temperature curve for said at least one hot plate, and to adjust the power supplied to said at least one hot plate based on said calculation only if the threshold temperature To is exceeded .
- the temperature reducing device accord ing to this embod iment has a control system configured to determine the temperature of the at least one hot plate by using a temperature curve for the hot plate and measuring the pulse duration during which the hot plate is supplied with voltage and from these data continuously calculate the temperature of the hot plate over time.
- the temperature reducing device can keep track of the temperature of the hot plate without need for a temperature sensor to sense the temperature of the hot plate . Since the temperature reducing device keeps track of the actual temperature of the hot plate, it only needs to interfere when the threshold temperature is actually exceeded .
- the temperature reducing device is configured to individually adjust the power supplied to the at least two hot plates.
- Fig . 1 a shows schematically a control knob and a hot plate
- Fig . 1 b shows schematically a hot plate, shows schematically a temperature reducing device according to an embodiment of the invention , shows schematically a temperature curve of a hot plate in the absence of temperature reduction accord ing to the invention , Fig . 4 shows schematically a temperature curve of a hot plate for which the temperature is reduced according to the invention ,
- 5a-c show schematically how a temperature reducing device accord ing to the invention reduces the pulse duration during which a hot plate is supplied with voltage
- Fig . 6a-b show examples of the temperature of a hot plate during cooling (a) and heating (b), respectively.
- DETAI LED DESCRI PTI ON OF EMBODI MENTS OF TH E I NVENTION A hot plate 1 and a control knob 3 of a cooking device (not shown) in the form of a cooking stove or a cooking top are schematically shown in Fig . 1 a.
- Fig . 1 b shows the hot plate in more detail.
- the hot plate 1 comprises a built-in heating element 1 a mounted under a glass ceramic surface 1 b, and a protective housing 1 c.
- a cooking device in the form of a cooking stove or a cooking top may comprise several hot plates 1 mounted under the glass ceramic surface 1 b.
- the heating element 1 a is supplied with power adjusted by the control knob 3.
- the control knob 3 comprises an adjustable bimetallic switch 3a which switches the voltage supply to the hot plate 1 on and off in pulses accord ing to a time schedule depending on the setting of a rotatable pointer 3b comprised in the control knob. The period may vary between 10 s to several minutes depending on the setting of the pointer 3b.
- the hot plate 1 is continuously supplied with power via the switch 3a.
- a thermostat (not shown) is however provided in the heating element 1 a for protection against overheating that may resu lt in damages to the glass ceramic surface 1 b.
- the thermostat normally switches the current to the hot plate off at a temperature of around 500- 550°C, i.e. well above the autoignition temperature of ord inary cooking oil .
- the thermostat is normally regularly activated as can be seen from Fig . 3, which schematically shows a temperature curve of a hot plate which is not affected by a temperature reducing device accord ing to the invention .
- a temperature reducing device 10 accord ing to an embodiment of the invention is schematically shown in Fig . 2 together with a hot plate 1 and a control knob 3.
- the temperature reducing device 10 comprises a control system 6 with a logic circuit or a microprocessor, a switch ing device 8 for switching the current to the hot plate 1 , and an in put terminal 4 for measuring the pulsed voltage su pply to the hot plate 1 .
- the temperature reducing device further comprises a sensor 2 for detecting the presence of a person and an in put terminal 9 for receiving a signal from the sensor 2.
- the temperature reducing device 10 is connected to the cooking device so that it via the input terminals 4 can measure the pulsed voltage from the control knob 3 to the hot plate 1 and so that it via the switching device 8 can switch the current to the hot plate 1 .
- the sensor 2 for detecting the presence of a person is mounted on or in the immediate vicin ity of the cooking device.
- the temperature of the hot plate 1 is determined by calculation . For the calculation , it is necessary to know how the temperature of the hot plate 1 develops over time during heating and cooling of the hot plate. Here, this is termed the temperature curve of the hot plate.
- the temperature curve is determined prior to usage of the temperature reducing device 10 , e.g . by measurement using a heat camera or similar, and is stored in the control system 6 as a mathematical expression or as a table.
- the temperature curve for a hot plate during cooling with no power supplied to the hot plate and during heating with power continuously supplied to the hot plate are shown in Fig . 6a (cooling) and Fig . 6b (heating).
- the temperature of the hot plate 1 over time can be described as a function of said temperature curve and the current su pplied to the hot plate.
- the temperature reducing device 10 measures pulse characteristics such as the pulse duration during which the control knob 3 supplies the hot plate 1 with current and the frequency of these pulses. From the measured pu lse characteristics and from the temperature curve of the hot plate 1 , the control system 6 calculates how the temperature of the hot plate 1 changes over time. The temperature is calculated by using the measured temperature curve , stored either in the form of a mathematical expression or as a table, of a hot plate.
- the control system 6 uses the present temperature of the hot plate and the duration of the pulse ATime as well as the frequency of the pulses to add a temperature value ATemp+ or subtracts a temperature value ATemp- from the present temperature and can thus follow the actual temperature of the hot plate.
- the calculation of the temperature of the hot plate shou ld be carried out continuously, i.e. also when the hot plate 1 is turned off by means of the control knob 3. In th is way, the control system 6 always keeps track of the present temperature of the hot plate 1 .
- control knob 3 When the control knob 3 has been turned to the maximum setting for a predetermined time, it can be assumed that the temperature of the hot plate 1 has reached its maximum temperature, and the maximum temperature is assumed to be the present temperature regardless of what the calculation says.
- control knob 3 When the control knob 3 has been turned to zero, i.e. turned off, for a predetermined time, it can be assumed that the temperature of the hot plate 1 is at approximately room temperature, about 20°C, and a corresponding temperature value is used regardless of what the calculation says.
- the hot plate 1 will assume a predictable temperature which can be determined by calibration , stored in the control system 6 and used instead of the calculated value.
- the temperature reducing device 10 As long as the sensor 2 detects the presence of a person in the vicin ity of the cooking device, the temperature reducing device 10 accord ing to the invention on ly calculates the temperature of the hot plate 1 and lets the person , via the control knob 3 of the cooking device, control the power supplied to the hot plate 1 . As long as a person is present near the cooking device, the hot plate may therefore reach any temperature which is below the temperature at wh ich the thermostat switches the current supply to the hot plate 1 off in order to protect the glass ceramic surface 1 b. However, when a person is not detected or has not been detected near the cooking device during a predetermined time, the temperature reducing device checks whether the hot plate 1 exceeds a predetermined threshold temperature To , above which e.g .
- the threshold temperature To shou ld be chosen such that the temperature in the cooking utensil is maintained in a range of normal cooking temperatures.
- a normal cooking temperature is here defined as a temperature below or around 200°C.
- the predetermined threshold temperature To shou ld therefore be maximum 350°C, preferably maximum 300°C, since the temperature within the cooking utensil will be lower than the temperature of the hot plate. If the threshold temperature To is not exceeded , the power supplied to the hot plate 1 is not affected by the temperature reducing device.
- the power supplied to the hot plate 1 is broken by means of the switch ing device 8 until the calculated temperature of the hot plate 1 is below the threshold temperature To.
- the control system 6 measures the frequency and duration of the pulses during which voltage is supplied to the hot plate and thereafter only adjusts the power supplied so that the temperature of the hot plate is just below the threshold temperature To as illustrated in Fig . 4.
- the temperature reducing device stops interfering with the power supplied to the hot plate 1 .
- the temperature reducing device shou ld know the frequency and duration of the voltage pulses that should be used over a longer period of time in order to reach a temperature just under the threshold temperature.
- Fig . 5a shows the voltage supplied to a hot plate 1 when the temperature is above the threshold temperature
- Fig . 5b shows the voltage supplied when the hot plate 1 is at a temperature below the threshold temperature.
- the control system 6 measures the duration and frequency of the pulse by means of which the hot plate is supplied with voltage and thereafter adjusts the pulse duration by switch ing off the current to the hot plate 1 when or just before the control knob 3 switches on the voltage supplied to the hot plate 1 or a short time before the control knob switches off the voltage supplied as shown in Fig . 5c, wherein the dashed line represents the voltage pulse at a temperature above the threshold temperature and the solid line represents an adjusted pulse duration .
- the duration of the voltage pulses is shortened .
- the temperature reducing device cannot supply the hot plate 1 with current but can only be used to switch off the current supply to the hot plate. Therefore, the temperature reducing device can never give the hot plate 1 a temperature which is higher than the setting of the control knob 3 allows, which is important for security reasons.
- the temperature reducing device may comprise a signalling device in the form of a signal lamp 7 and/or a buzzer 5, which signals to a user of the cooking device that a tem perature adjustment is being or has been performed .
- the temperature reducing device may also be equipped with a manual override device, here shown in the form of a button 1 1 , configured to allow the hot plate 1 to reach a temperature above the threshold temperature during a predetermined time. When the button 1 1 is momentarily pressed in , the hot plate is allowed to reach the temperature it is given by the control knob 3 during a predetermined time.
- the temperature reducing device may comprise a switch ing device for each hot plate respectively as well as input terminals for measuring pulsed the voltage supplied to each hot plate respectively, or other means for determining the pulse characteristics of each hot plate respectively.
- the temperature curve of each of the hot plates is stored in the control system.
- the temperature reducing device may also in this embodiment comprise a sing le control system and a sing le sensor for detecting the presence of a person .
- Such a temperature reducing device can reduce the temperature of several hot plates individually. Thus, it may reduce the temperature of only one hot plate and leave the other hot plates unaffected .
- Th is means that cooking at normal cooking temperatures, e.g .
- the temperature reducing device may in this embodiment comprise one or several manual override devices. If a sing le manual override device is used , it may be adapted so as to allow only a specific hot plate, e.g . the hot plate last turned on , to exceed the threshold temperature and only during a set time.
- the temperature reducing device 10 has a control system 6 which is configured to adjust the power supplied to the hot plate 1 without calculating the actual temperature of the hot plate 1 .
- the control system 6 via the input terminal 9 receives a signal from the sensor 2 that no person is present in the vicinity of the stove , it checks the pulse characteristics of the pulsed voltage supplied to the hot plate and by means of the switch ing device 8 adjusts the power supplied to the hot plate 1 such that the pulse length results in a temperature below a predetermined threshold temperature To.
- the control system may be configured such that adjustment is on ly carried out when no person has been detected in the vicinity of the cooking device for a predetermined time.
- the control knob may be replaced by e.g . a touch control panel.
- the control system is configured to receive a signal transmitted by the touch control panel and thereby determine the pulse characteristics of the pulse during which the hot plate is supplied with voltage.
- the switch ing device may be one or more relays, triacs or similar, e.g . coupled in series with the current to each hot plate.
- the temperature reducing device accord ing to the invention may for example be built into the cooking device or mounted on or next to the cooking device.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Food Science & Technology (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Electric Stoves And Ranges (AREA)
- Cookers (AREA)
- Baking, Grill, Roasting (AREA)
- Control Of Resistance Heating (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE1200441A SE536689C2 (en) | 2012-07-13 | 2012-07-13 | Device that prevents stove fire and allows normal cooking to continue |
PCT/SE2013/050825 WO2014011101A1 (en) | 2012-07-13 | 2013-06-28 | A device and a method for reducing the temperature of a cooking device |
Publications (2)
Publication Number | Publication Date |
---|---|
EP2872831A1 true EP2872831A1 (en) | 2015-05-20 |
EP2872831A4 EP2872831A4 (en) | 2016-03-23 |
Family
ID=49916393
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP13817618.5A Withdrawn EP2872831A4 (en) | 2012-07-13 | 2013-06-28 | A device and a method for reducing the temperature of a cooking device |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP2872831A4 (en) |
SE (1) | SE536689C2 (en) |
WO (1) | WO2014011101A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2019218086A1 (en) * | 2018-05-18 | 2019-11-21 | Pioneering Technology Corp. | Temperature modulation in a cooking apparatus |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3781506A (en) * | 1972-07-28 | 1973-12-25 | Gen Electric | Non-contacting temperature measurement of inductively heated utensil and other objects |
DE3118399C2 (en) * | 1981-05-09 | 1986-03-27 | Diehl Gmbh & Co, 8500 Nuernberg | Arrangement for sensorless temperature determination on a stove |
US4604518A (en) * | 1984-11-16 | 1986-08-05 | General Electric Company | Display arrangement for cooking appliance with power control using heater energy counter |
US5717188A (en) * | 1995-06-12 | 1998-02-10 | Vaillancourt; Alain | Safety device for a heating appliance |
CA2193533A1 (en) * | 1996-12-20 | 1998-06-20 | Jozef Rak | Fire prevention device for electric cooking stove |
JP4443366B2 (en) * | 2004-10-01 | 2010-03-31 | 三洋電機株式会社 | Cooker |
JP4992553B2 (en) * | 2007-05-31 | 2012-08-08 | パナソニック株式会社 | Heating device |
ES2648812T3 (en) * | 2010-06-10 | 2018-01-08 | Panasonic Corporation | Induction heating cooker |
-
2012
- 2012-07-13 SE SE1200441A patent/SE536689C2/en not_active IP Right Cessation
-
2013
- 2013-06-28 WO PCT/SE2013/050825 patent/WO2014011101A1/en active Application Filing
- 2013-06-28 EP EP13817618.5A patent/EP2872831A4/en not_active Withdrawn
Also Published As
Publication number | Publication date |
---|---|
WO2014011101A1 (en) | 2014-01-16 |
SE536689C2 (en) | 2014-05-27 |
SE1200441A1 (en) | 2014-01-14 |
EP2872831A4 (en) | 2016-03-23 |
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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
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17P | Request for examination filed |
Effective date: 20150112 |
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AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
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AX | Request for extension of the european patent |
Extension state: BA ME |
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DAX | Request for extension of the european patent (deleted) | ||
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: BECKIUS, JAN Inventor name: KJELLANDER, DAN |
|
RA4 | Supplementary search report drawn up and despatched (corrected) |
Effective date: 20160222 |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: G05D 23/19 20060101ALI20160216BHEP Ipc: H05B 1/02 20060101ALI20160216BHEP Ipc: F24C 7/08 20060101AFI20160216BHEP |
|
17Q | First examination report despatched |
Effective date: 20190613 |
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STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN |
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18W | Application withdrawn |
Effective date: 20190923 |
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RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: N'CARE AB |