EP3503672A1

EP3503672A1 - Induction cooktop

Info

Publication number: EP3503672A1
Application number: EP17208843.7A
Authority: EP
Inventors: Çaglar Islek
Original assignee: Vestel Elektronik Sanayi ve Ticaret AS
Current assignee: Vestel Elektronik Sanayi ve Ticaret AS
Priority date: 2017-12-20
Filing date: 2017-12-20
Publication date: 2019-06-26
Anticipated expiration: 2037-12-20
Also published as: TR201722204A2; EP3503672B1

Abstract

An induction cooker comprising a cooking surface, one or more movable induction coils movable under said cooking surface, and a sensor for detecting a cooking vessel on said cooking surface, wherein said sensor is operable to determine (i) the location and/or (ii) the size of said cooking vessel, and wherein said cooker is operable to select a coil and move that coil to selected location based on information from said sensor.

Description

FIELD

The invention relates to induction cooktops. The invention further relates to a method for operating an induction cooktop.

BACKGROUND

Induction cooktops (also known as "induction hobs" or "induction stoves") typically use fixed induction coils in combination with complex circuit arrangements including, for example, current measuring elements, in order to detect the position and/or size of cooking vessels on a cooking surface. Alternative sensor systems are based on multiple LED or light sensors, but such systems are very high cost.
See, for example, US 8,791,398 in which a current measuring element is used to detect the occupancy of a cooking sub-zone by a food-preparation vessel. The induction cooktop described includes a cooking zone, and a circuit arrangement for operating the cooking zone. The circuit arrangement has a parallel circuit, in which two inductors are connected in a parallel manner. Apparatus is configured to detect occupancy of at least one cooking sub-zone of the cooking zone by a food preparation vessel and includes a current measuring element which is connected in series to the parallel circuit.
US 4,334,135 discloses a utensil detection arrangement for an induction heating apparatus which provides a signal indicative of an off-centre position of a cooking utensil supported on a cooking surface which overlies an induction heating coil. The detection arrangement comprises a conductive loop configuration located intermediate the heating coil and the cooking utensil in a plane parallel to the plane of the cooking surface and concentric with respect to the axis of the coil. The conductive loop is linked with the magnetic flux generated by the induction heating coil, which flux changes as a result of the position of a cooking utensil with respect to the axis of the coil and thereby generates a signal which changes in amplitude as a result of utensil position.
US 5,714,739 discloses a control device particularly for induction cooking ranges with multiple heating units which comprise a plurality of induction coils. The induction coils can be electrically parallel connectable to each other. The device also comprises elements for engaging the induction coils connecting individual induction coils or pairs of induction coils to a single electric power converter, and elements for sensing the presence or the absence of a pot or the presence of an unadapted pot on a particular induction coil; the sensor elements are electrically connected to control means that select, on user's command, the induction coils to be activated and the power to be carried to each individual induction coil, and control the sending of shares of the power generated by the electronic converter to each active induction coil, at the same time limiting the periodic variations in the current absorbed from the mains, within the limits allowed by statutory provisions regarding so-called "flicker".
There is an on-going need for cooktops which are simpler, cheaper and/or more efficient.

SUMMARY OF INVENTION

In a first aspect, the invention provides an induction cooktop comprising:

a cooking surface;
one or more movable induction coils movable under said cooking surface;
a sensor for detecting a cooking vessel on said cooking surface;

Preferably, the sensor is a movable sensor.
In a second aspect, the invention provides an induction cooktop comprising:

a cooking surface;
one or more induction coils, optionally movable under said cooking surface;
a movable sensor for detecting a cooking vessel on said cooking surface; wherein said sensor is operable to determine (i) the location and/or (ii) the size of said cooking vessel;

Both aspects may contain any of the following preferred features, alone or in combination.
The sensor is preferably a movable ultrasound sensor. It is further preferred that said movable ultrasound sensor may be mounted on a rail system.
Preferably the one or more movable induction coils include coils of different sizes. It is further preferred that said cooktop is operable to select a size of coil and move that coil to a selected location based on information from said sensor.
In the cooktop of the invention preferably a plurality of induction coils may be controlled by a single control or by a single slider.
Preferably the cooktop of the invention contains only one sensor, being a movable ultrasound sensor.
The cooktop of the invention preferably includes a display unit, more preferably a touchscreen display unit. Said display unit may preferably display (i) the location and/or (ii) the size of said cooking vessel based on information from said sensor.
In a third aspect, the invention provides a method for operating an induction cooktop comprising:

detecting a cooking vessel on a cooking surface by lateral movement of an ultrasound sensor;
based on detection of location of said cooking vessel and/or detection of size of said cooking vessel, selecting at least one movable induction coil; and
moving said at least one movable induction coil to location of said cooking vessel.

In a fourth aspect, the invention provides a method for operating an induction cooktop comprising:

providing one or more movable induction coils movable under a cooking surface; and/or
providing a movable ultrasound sensor for detecting a cooking vessel on said cooking surface, and operating said sensor to determine (i) the location and/or (ii) the size of said cooking vessel;

Preferably said method further comprises operating said cooktop to select a coil and move that coil to selected location based on information from said sensor. Said method may preferably further comprise operating said cooktop to select a size of coil.
All features described in connection with any aspect of the invention can be used with any other aspect of the invention.

BRIEF DESCRIPTION OF FIGURES

The invention will be further described with reference to a preferred embodiment, as shown in the drawings in which:

Figure 1 shows a plan view (from above) of a cooktop according to the invention, in which a movable ultrasound sensor and movable induction coils are shown.
Figure 2 shows a side elevation of the cooktop according to the invention, showing a moveable ultrasound sensor.
Figure 3 shows a plan view of the cooktop of figure 1 in use.
Figure 4 shows a side elevation of the cooktop of figure 1 in use.

DETAILED DESCRIPTION

Figure 1 shows a plan view of a cooktop 10 according to an embodiment. The cooktop 10 comprises a substantially planar cooking surface 12 arranged to receive one or more cooking vessels (not shown in Figure 1). A plurality of movable coils 20, 22, 24, 26, 28 are arranged beneath the cooking surface 12 and configured, in use, to move to specific locations along a rail system 50. A movable ultrasound sensor 40 is also shown. Control units 30 are shown. A rail system 50 in a grid structure is illustrated, by which the induction coils may be moved and positioned where needed according to the position of the cooking vessels detected.
Figure 2 shows a side elevation of the cooktop 10 according to an embodiment. A movable ultrasound sensor 40 is shown, under the cooking surface 12.
Figure 3 shows a plan view of the cooktop of figure 1 in use. A cooking vessel 60 is shown on the substantially planar cooking surface 12. A selected movable induction coil 28 is shown being moved below the cooking surface 12 to the location of the cooking vessel 60.
Figure 4 shows a side elevation of the cooktop of figure 3, in use. The cooking vessel 60 is shown on the cooking surface 12 with the movable induction coil 28 moving into position beneath the cooking surface 12.
The invention relates to induction cooktops 10 having a movable coil system (e.g. including movable induction coils 20, 22, 24, 26, 28 and rail system 50) and/or a movable sensor 40.
In a preferred embodiment, the induction cooktop according to the invention includes one or more movable induction coils, and a sensor.
In another embodiment, equally preferred, the induction cooktop according to the invention includes one or more induction coils and a movable sensor.
In a more preferred embodiment, the induction cooktop according to the invention includes one or more movable induction coils and a movable sensor.
In all embodiments, the induction cooktop includes a sensor for detecting a cooking vessel on the cooking surface, the location of the cooking vessel on the cooking surface, and/or the size of the cooking vessel. Preferably the sensor detects at least the location of the cooking vessel.
In embodiments containing one or more movable induction coils, the induction cooktop then operates the movable coil system based on the sensor information. Thus, upon detecting the cooking vessel, the induction cooktop selects the coil and moves the selected coil to the location of the cooking vessel.
Preferably, the sensor may detect the size of the cooking vessel in addition to its location. In embodiments where the sensor detects the size of the cooking vessel, preferably the induction cooktop selects a size of coil based on the size of the cooking vessel. In embodiments having movable induction coils, the selected coil is then moved to the location of the cooking vessel.
The movable induction coils used in the induction cooktops of the invention differ from the fixed induction coils or fixed induction elements that are used in current induction cooktops in that they are not stationary. In particular the movable induction coils are mobile and are not limited to one particular position relative to the cooking surface.
Typically the induction cooktop of the invention comprises a number of movable induction coils. These are movable under the cooking surface during operation of the induction cooktop. For example, using rails in a grid structure as shown in figure 1.
The movable induction coils may be of essentially any shape, but are typically of a regular shape such as a shape that is approximately circular, oval or rectangular.
Typically the induction cooktop includes movable induction coils having a variety of different sizes. There may be two or more coils, or groups of coils, of essentially the same size. Equally possibly, the coils may all be of different sizes. The cooktop may include some coils of the same size as well as a number of coils of differing sizes.
The mobility of the movable induction coils provides for more efficient use of the cooking surface. In combination with the variety of sizes of movable induction coils, a higher proportion of the cooking surface may be used in comparison with conventional induction cooktops having fixed induction coils.
In embodiments in which the induction coils are not movable, i.e. are immobile or fixed, there are typically also included a number of induction coils. These may be of essentially any shape, but are typically of a regular shape such as a shape that is approximately circular, oval or rectangular. Typically the induction cooktop includes induction coils having a variety of different sizes. There may be two or more coils, or groups of coils, of essentially the same size. Equally possibly, the coils may all be of different sizes. The cooktop may include some coils of the same size as well as a number of coils of differing sizes.
In the cooktop according to the invention, the sensor is preferably a movable sensor. More preferably it is a movable ultrasound sensor. It is preferred, in all aspects and embodiments of the invention, that only one sensor is used, which is a movable ultrasound sensor.
The movable ultrasound sensor may preferably be mounted on a rail system.
The movement of suitable rail systems typically may be provided by a balancing wheel. The rotation of the wheel typically may be via a motor. The motor typically keeps a constant rotation speed to ensure a constant sensor velocity.
Preferably, the ultrasound sensor may have a maximum range that corresponds to the dimension of the cooktop. The sensor thus only detects cooking vessels as an obstacle.
The induction cooktop of the invention starts to operate when a control or slider is operated. Typically this may be a heating control or heating slider.
The operation of the control/slider starts movement of the ultrasound sensor. For example, it starts the motor which moves the rail system on which the sensor may be mounted.
The moving ultrasound sensor scans the heating surface of the cooktop in one dimension. The sensor detects the position of a cooking vessel via a distance measurement. This information is sent to a controller.
Thus in a preferred embodiment, applicable to all aspects of the invention, the cooktop further comprises a controller.
The controller extracts the position of the cooking vessel by mapping the cooking surface. The sensor also measures time and this is also recorded by the controller in order to extract the radius of the cooking vessel (if it is a circular vessel) or dimensions of base of the vessel (if another type of vessel). This can be achieved, in embodiments, by the contant speed of the sensor.
The distance measurement may be added to the radius or base dimension of the vessel in order to determine the surface area to be heated. The controller determines this area by mapping.
Typically, there may be a number of induction coils under the cooking surface, which may be of different sizes. Preferably, the controller will select the coil having dimensions that are most suitable to provide energy efficiently over the necessary surface area to heat the cooking vessel detected. In embodiments having movable induction coils, the selected coil can be moved into position, for example, by rails in a grid structure under the cooking surface, as shown in figure 1.
The cooktop according to the invention has a cooking surface that can be used efficiently. Further the cooktop of the invention may be used to heat more than four cooking vessels at the same time. Cooking vessels placed in empty areas are detected by the sensor and an appropriate coil will be designated and despatched by the controller.
The cooktop can be operated using only a single control/slider. For example, the heat level may be adjusted for a first cooking vessel. Pushing the control or slider (as a button) records this level. Subsequently a second push (as a button) returns to adjustment mode such that it is possible to use the control/slider to adjust the heat level for a second cooking vessel. This sequence can be repeated to adjust heat levels for each cooking vessel.
Alternatively, or in addition, the cooktop can include a display unit. For example a touchscreen display unit may be included.
Preferably said display unit visually depicts information determined by the sensor, for example location of a cooking vessel and/or its size.
It is preferred that said display unit is operable to provide user control of the induction cooktop. For example, a touchscreen display unit that allows for selection of the area of the induction cooktop to be heated. Control of the level of heat to be applied may be achieved, for example, by a further touchscreen function and/or use of a control dial, button, slider or similar unit in combination with the display unit and controller.
The invention further provides a method for operating an induction cooktop comprising: detecting a cooking vessel on a cooking surface by lateral movement of an ultrasound sensor; based on detection of location of said cooking vessel and/or detection of size of said cooking vessel, selecting at least one movable induction coil; and moving said at least one movable induction coil to location of said cooking vessel.
The invention further provides a method of operating an induction cooktop, which comprises: providing one or more movable induction coils movable under a cooking surface; and/or providing a movable sensor for detecting a cooking vessel on said cooking surface, and operating said sensor to determine (i) the location and/or (ii) the size of said cooking vessel.
The methods of the invention are applicable to all embodiments of the cooktop described hereinbefore.
Whilst the invention has been described with reference to a preferred embodiment, it will be appreciated that various modifications are possible within the scope of the invention.
In this specification, unless expressly otherwise indicated, the word 'or' is used in the sense of an operator that returns a true value when either or both of the stated conditions is met, as opposed to the operator 'exclusive or' which requires that only one of the conditions is met. The word 'comprising' is used in the sense of 'including' rather than to mean 'consisting of'. All prior teachings acknowledged above are hereby incorporated by reference. No acknowledgement of any prior published document herein should be taken to be an admission or representation that the teaching thereof was common general knowledge in Europe or elsewhere at the date hereof.

Claims

An induction cooktop comprising:
a cooking surface;

one or more movable induction coils movable under said cooking surface;

a sensor for detecting a cooking vessel on said cooking surface;
wherein said sensor is operable to determine (i) the location and/or (ii) the size of said cooking vessel;
and wherein said cooktop is operable to select a coil and move that coil to a selected location based on information from said sensor.
The cooktop as claimed in claim 1 wherein said sensor is a movable sensor.
An induction cooktop comprising:
a cooking surface;

one or more induction coils optionally movable under said cooking surface;

a movable sensor for detecting a cooking vessel on said cooking surface;
wherein said sensor is operable to determine (i) the location and/or (ii) the size of said cooking vessel;
and wherein said cooktop is operable to select and optionally move a coil based on information from said sensor.
The cooktop as claimed in claim 2 or claim 3, wherein said movable sensor is a movable ultrasound sensor.
The cooktop as claimed in any of claims 2 to 4 wherein said sensor is mounted on a rail system.
The cooktop as claimed in any preceding claim wherein said one or more induction coils include coils of different sizes.
The cooktop as claimed in any preceding claim wherein said cooktop is operable to select a size of coil based on information from said sensor.
The cooktop as claimed in any preceding claim wherein a plurality of said one or more induction coils are controlled by a single control or by a single slider.
The cooktop as claimed in any preceding claim containing only one sensor, said sensor being a movable ultrasound sensor.
The cooktop as claimed in any preceding claim further comprising a display unit, preferably a touchscreen display unit.
The cooktop as claimed in claim 10 wherein said display unit is operable to display (i) the location and/or (ii) the size of said cooking vessel based on information from said sensor.
A method for operating an induction cooktop comprising:
detecting a cooking vessel on a cooking surface by lateral movement of an ultrasound sensor;

based on detection of location of said cooking vessel and/or detection of size of said cooking vessel, selecting at least one movable induction coil; and

moving said at least one movable induction coil to location of said cooking vessel.
A method for operating an induction cooktop comprising:
providing one or more movable induction coils movable under a cooking surface;
and/or

providing a movable sensor for detecting a cooking vessel on said cooking surface, and operating said sensor to determine (i) the location and/or (ii) the size of said cooking vessel.
The method of claim 12 or claim 13 wherein said sensor is a movable ultrasound sensor.
The method of claim 13 or claim 14 further comprising operating said cooktop to select a coil and move that coil to a selected location based on information from said sensor; and/or further comprising operating said cooktop to select a size of coil and move that coil to a selected location based on information from said sensor.