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WO2011061482A1 - Capteur d'ébullition - Google Patents

Capteur d'ébullition Download PDF

Info

Publication number
WO2011061482A1
WO2011061482A1 PCT/GB2010/002106 GB2010002106W WO2011061482A1 WO 2011061482 A1 WO2011061482 A1 WO 2011061482A1 GB 2010002106 W GB2010002106 W GB 2010002106W WO 2011061482 A1 WO2011061482 A1 WO 2011061482A1
Authority
WO
WIPO (PCT)
Prior art keywords
water
kettle
signals
boiling
appliance
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.)
Ceased
Application number
PCT/GB2010/002106
Other languages
English (en)
Inventor
David Robert Harvey
Shaun Derrick Morgan
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kenwood Ltd
Original Assignee
Kenwood Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kenwood Ltd filed Critical Kenwood Ltd
Publication of WO2011061482A1 publication Critical patent/WO2011061482A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • 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
    • 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
    • A47J27/21158—Devices to detect overheating or boiling with a single control element or unit
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/26—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
    • G01F23/263—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields by measuring variations in capacitance of capacitors

Definitions

  • This invention relates to a boiling sensor, and it relates more particularly to such a sensor usable in electric kettles, or other water-boiling appliances, to reliably detect when the water boils.
  • a detection element of the sensor is also usable to detect the level of water in the kettle or other appliance.
  • Electric kettles are widely used in domestic kitchens in preference to kettles that require an external source of heat. By and large, such appliances are reliable and speedy in operation, and, being electrically powered, can readily be provided with control circuitry to detect when the water boils and/or to detect the onset of potentially damaging boil-dry situations, and to disconnect the supply of electrical power to the heating element when appropriate.
  • Various arrangements are known for effecting such detection and control, and many of these are proven and highly reliable, though most require quite complex electro-mechanical arrangements; boiling detection, for example, typically requiring the provision of a duct to carry steam from the region above the water line down to an electrical circuit in or near the base of the kettle which responds to the ducted steam by throwing a switch that disconnects the kettle's heating element from the mains power supply.
  • One object of this invention is to provide an improved boiling sensor, for an electric kettle or other electrically powered water-boiling appliance, which is wholly electronic, making it reliable, and economic to incorporate into a kettle or other appliance.
  • a boiling sensor including a capacitive detection element connected to electronic circuitry arranged to provide, when the water boils, electrical signals having a particular characteristic and there is further provided recognition means for recognising signals having said characteristic and for responding to such recognition by developing a control signal, such as a switching signal usable to disconnect electrical power from a heating element of the kettle or other appliance.
  • Another object of the invention is to configure such a sensor to detect or monitor at least one other criterion or parameter associated with the kettle or other appliance, such as a level of water to which the kettle or other appliance is filled.
  • the electronic circuitry associated with the capacitive detection element is preferably configured to provide electrical output signals with one characteristic indicative of water level and with another characteristic indicative of boiling.
  • the recognition means is configured to differentiate between electrical signals having the two characteristics and to provide as outputs both appropriate control signals, such as switching signals, and parameter magnitude signals.
  • some embodiments of the invention further comprise means for utilising signals indicative of a detected water level and of the known power of a heating element of the kettle or other appliance, to predict the time it should take to boil the water, and for comparing the predicted time with the actual time taken to boil the water, and means for generating a warning if the compared times differ by more than a predetermined amount, indicative of a possible need for descaling the kettle or other appliance.
  • Said warning may conveniently comprise a visual warning provided by illumination of a light-emitting device.
  • the invention also encompasses an electric kettle or other water-heating appliance incorporating any of the aforesaid electronic boiling sensors.
  • Figure 1 shows a graph indicative of the operation of the detecting element of a sensor in accordance with one example of the invention
  • Figure 2 shows, in block diagrammatic form certain elements of the sensor
  • Figure 3 shows in more detail the circuitry utilised in a sensor comprising one embodiment of the invention.
  • Figure 1 shows a graph indicative of the measured characteristics of electrical signals derived from an electronic oscillator circuit connected to the capacitive detecting element used in a boiling sensor according to one example of the invention. It will be appreciated in this respect that the kettle element was switched off when boiling was detected, and then repeatedly re-energised once the water temperature had fallen by a predetermined amount.
  • capacitive detection means provided on or otherwise incorporated into an internal surface of a kettle in any convenient format, for example as plate-like or linear electrodes, are coupled to an electronic oscillator circuit.
  • the oscillator is set up, in this instance, to generate a square wave, the frequency of which is influenced by the capacitance between the electrodes of the detection means, and a microprocessor is provided to monitor the frequency, or a derivative of the frequency, such as its rate of change.
  • Figure 1 shows, as a solid line 1 , the actual temperature of the water in the kettle and, as a dashed line 2, the frequency of the oscillator.
  • the rate of change of the oscillator frequency is also shown on the graph of Figure 1 , as a solid line 3. It will be observed that either or both characteristics (i.e. frequency 2 and rate of change of frequency 3) can be detected by the microprocessor and used to develop control signals that can be employed to reliably switch off the heater when boiling occurs.
  • an all-electronic boiling sensor of this kind provides important advantage over, for example conventional boiling cut-outs based on the use of steam tubes to duct steam down to circuitry located in the base of a kettle.
  • the steam ducts tend to become obstructed with lime deposits over extended use, thus rendering the cut-out (or so-called "steam-stat") less efficient over time and leading to over-long boiling times, which wastes energy and stresses the elements.
  • the capacitive detection means can, of course, still be used to sense the water level in the kettle, and this example of the invention thus provides useful duality of purpose, functioning as an efficient level sensor and boiling sensor.
  • this duality of purpose leads to further flexibility in operation of the kettle, as it is possible, based upon the detected water level and the known power of the heating element, to predict the time it should take to boil the water. If the predicted time does not correspond (within reasonable tolerance) to the time it actually takes the water to boil, as measured by the capacitive detection means and its associated circuitry, the microprocessor can be caused to generate a signal which illuminates an LED, or stimulates some other form of display (audible and/or visual) to warn the user that the kettle may require descaling.
  • electrodes 10 and 12 forming the detection elements of a boiling sensor in accordance with one example of the invention are applied to the internal wall of a kettle body 14.
  • the electrodes 10 and 12 may be attached or deposited in any convenient manner upon, or incorporated into, the body 14, with part of each disposed above the maximum water level.
  • the attachment or deposition technique used to apply the electrodes 10 and 12 to the internal wall of the body 14 is determined at least to a degree by the materials of which the kettle body is made.
  • the electrodes 10 and 12 may be provided directly upon the interior surface of the body 14.
  • the kettle is metal bodied, it is necessary either to pre-form one or more electrically insulating layers on at least the electrode-bearing regions of the internal surface of the kettle body 14 to support the electrodes 10 and 12, or to provide the electrodes 10 and 12 with respective backings of electrically insulating material prior to attaching them to the metal body.
  • the electrodes can be of any convenient shape, such as the rectangular plate format shown and, indeed, they may be "tuned” in shape and/or dimensions to achieve a desired electrical performance from any given body 14.
  • the electrodes need not be plate-like or widely separated, however, and can alternatively be configured, for example, into nested spirals, or elongated, sinuous forms.
  • the electrodes 10 and 12 are coupled to an oscillator circuit 16 and a microprocessor 18 is connected to monitor the performance of the oscillator 16, for example by monitoring its frequency, or a rate of change of its frequency, in order to sense when the water in the kettle boils.
  • microprocessor 18 provides, as an output, a control signal on line 20 which is usable to disconnect the heating element of the kettle from the electrical power supply.
  • the oscillator 16 comprises a group of three inverted Schmitt trigger circuits 24a, 24b and 24c (each of the type designated 40106N), interconnected in known manner in series with a pair of resistors 22a and 22b, to generate (with the variable capacitance of the electrodes 10 and 12, the leads from which are connected into the circuit at connection points 10a and 12a respectively as shown in Figure 3) a square wave, the frequency of which is influenced by the capacitance, i.e. the dielectric, between the electrodes 10 and 12.
  • the capacitance i.e. the dielectric
  • the oscillator 16 is connected to pin 7 of the microprocessor 18 which, in this example, is an integrated circuit of the type designated 16F676DIL, and the microprocessor 18 measures the period of the square wave, using a timer, or counts the number of rising or falling edges in a predetermined time to determine the oscillator frequency.
  • the frequency may be used as the measured parameter, as aforesaid, or the period of one sample may be compared with that of the previous sample to calculate any gradient of a frequency change.
  • the level sensing operation uses the same electrodes 10 and 12, and the same microprocessor 18, and can be implemented in any convenient manner, such as those disclosed in the aforementioned GB-A-2358789.
  • the level-sensing output can be used to inhibit the application of power to the heating element if the kettle does not contain sufficient water and/or if the kettle contains too much water.
  • level sensing is carried out only when the kettle is first connected to the power source; i.e. when the water is cold, simply to check that the kettle has not been under- or over-filled at the outset.
  • the water level is sensed throughout the operation of the kettle, or is switched in to operation again after boiling has been detected by the circuit of Figures 2 and 3, to ensure that the kettle is not allowed to boil dry.
  • This facility can avoid the need for a separate boil-dry protector of the kind usually employed.
  • battery power may be provided to ensure that the level can be sensed whilst filling the kettle.
  • the level can be indicated by means of a strategically placed display of any convenient kind, such as a liquid crystal display (LCD), a light-emitting diode (LED) display, an electroluminescent display or one or more neon lamps.
  • LCD liquid crystal display
  • LED light-emitting diode
  • electroluminescent display or one or more neon lamps.
  • the control signal used to switch off the kettle or other appliance can be used to illuminate (or extinguish) a visual indicator to show that the water has boiled.
  • the application of the electrodes to the kettle body 14 may be used to provide additional visual features, such as a volume capacity bar.

Landscapes

  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Electromagnetism (AREA)
  • Thermal Sciences (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Cookers (AREA)

Abstract

La présente invention concerne un capteur d'ébullition d'eau pouvant être utilisé dans des bouilloires électriques ou d'autres appareils électriques faisant bouillir de l'eau intégrant un élément chauffant alimenté à l'électricité, afin de détecter de façon fiable à quel moment l'eau bout. Le capteur est entièrement électronique et de préférence peut être également utilisé pour détecter le niveau de l'eau. Il utilise un élément de détection à capacité comprenant des électrodes (10, 12), disposé en contact avec de l'eau dans la bouilloire ou l'autre appareil électrique, et connecté à un oscillateur (16) ou un autre circuit générant des signaux électriques qui sont influencés par la capacité entre les électrodes (10, 12) et qui montrent une réponse caractéristique particulière et reproductible (2, 3) lorsque l'eau bout. Des circuits électriques (18) permettent de reconnaître des signaux électriques possédant la réponse caractéristique susmentionnée, puis de produire des signaux de commande pouvant servir à déconnecter l'alimentation de l'élément chauffant lorsque l'eau bout. L'invention concerne également une bouilloire électrique ou un autre appareil électrique faisant chauffer de l'eau intégrant un tel capteur.
PCT/GB2010/002106 2009-11-17 2010-11-16 Capteur d'ébullition Ceased WO2011061482A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0920033A GB2475324A (en) 2009-11-17 2009-11-17 Boiling sensor for water-boiling appliances
GB0920033.8 2009-11-17

Publications (1)

Publication Number Publication Date
WO2011061482A1 true WO2011061482A1 (fr) 2011-05-26

Family

ID=41509443

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2010/002106 Ceased WO2011061482A1 (fr) 2009-11-17 2010-11-16 Capteur d'ébullition

Country Status (2)

Country Link
GB (1) GB2475324A (fr)
WO (1) WO2011061482A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106289449A (zh) * 2015-06-11 2017-01-04 陈俊平 电容式水位水量检测装置及煮水壶、检测方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2498823B (en) * 2012-07-03 2013-12-11 Robert Hill A water heater
US10418723B1 (en) 2017-12-05 2019-09-17 Rockwell Collins, Inc. Dual polarized circular or cylindrical antenna array

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5756876A (en) 1995-09-28 1998-05-26 Endress + Hauser Gmbh + Co. Method of setting the switching point of a capacitive level limit switch
GB2358789A (en) 2000-02-07 2001-08-08 Otter Controls Ltd Liquid heating device with excessive or insufficient water level protection means.
GB2429124A (en) * 2005-08-11 2007-02-14 Otter Controls Ltd Scale detection on water heating elements
WO2009060192A2 (fr) * 2007-11-07 2009-05-14 Otter Controls Limited Récipient de chauffage de liquide et commande
CN101561307A (zh) * 2009-05-21 2009-10-21 晶辉电器（深圳）有限公司 电子液体位置检测和显示装置及其应用方法

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3784788A (en) * 1971-05-04 1974-01-08 Belling & Co Ltd Electric liquid boiling apparatus having an electronic temperature sensor control
GB8615279D0 (en) * 1986-06-23 1986-07-30 Procter Silex Canada Inc Electronic kettle
DE19744916B4 (de) * 1997-10-10 2004-10-28 BSH Bosch und Siemens Hausgeräte GmbH Wasserkocher mit Füllstandsdetektor
GB2358530B (en) * 2000-01-24 2003-10-01 Otter Controls Ltd Improvements relating to controls for liquid heating appliances
US6818867B2 (en) * 2001-06-09 2004-11-16 Braun Gmbh Method for heating liquid in an electric kettle
GB2407478B (en) * 2003-10-28 2005-09-28 Tarquin Andrew Richard Stehle Domestic electronic kettle
GB2432212B (en) * 2005-11-15 2007-12-05 Crastal Technology Boiling water estimation methods and apparatus
AU2007250521A1 (en) * 2006-05-12 2007-11-22 Sunbeam Corporation Limited Improved temperature sensor for an electric heating vessel
FR2901955B1 (fr) * 2006-06-05 2010-03-26 Seb Sa Appareil menager pour le chauffage de liquide
US8097834B2 (en) * 2007-06-28 2012-01-17 Strix Limited Liquid heating vessels

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5756876A (en) 1995-09-28 1998-05-26 Endress + Hauser Gmbh + Co. Method of setting the switching point of a capacitive level limit switch
GB2358789A (en) 2000-02-07 2001-08-08 Otter Controls Ltd Liquid heating device with excessive or insufficient water level protection means.
GB2429124A (en) * 2005-08-11 2007-02-14 Otter Controls Ltd Scale detection on water heating elements
WO2009060192A2 (fr) * 2007-11-07 2009-05-14 Otter Controls Limited Récipient de chauffage de liquide et commande
CN101561307A (zh) * 2009-05-21 2009-10-21 晶辉电器（深圳）有限公司 电子液体位置检测和显示装置及其应用方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106289449A (zh) * 2015-06-11 2017-01-04 陈俊平 电容式水位水量检测装置及煮水壶、检测方法

Also Published As

Publication number Publication date
GB2475324A (en) 2011-05-18
GB0920033D0 (en) 2009-12-30

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