WO2008110450A2

WO2008110450A2 - Cooking hob and method for detecting a cooking utensil

Info

Publication number: WO2008110450A2
Application number: PCT/EP2008/052268
Authority: WO
Inventors: Pablo Jesus Hernandez Blasco; Alfonso Lorente Perez; Luis Angel Barragan Perez; José Miguel Burdio Pinilla
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2007-03-13
Filing date: 2008-02-25
Publication date: 2008-09-18
Also published as: ES2321262B1; DE112008000414A5; WO2008110450A3; ES2321262A1

Abstract

The invention relates to a cooking hob with a cooking hob plane (10) for placing a cooking utensil (18) and a switch (16) arranged beneath the cooking hob plane (10) for activating at least one function of the cooking hob. According to the invention, the switch can be actuated by magnetic force. In order to make use of the magnetic force applied to or produced by the cooking utensil (18), it is proposed that the switch (16) is configured to magnetically interact with a cooking utensil (18) arranged on the cooking hob plane (10).

Description

Hob and method for detecting a cookware part

The invention relates to a hob according to the preamble of claim 1, a cookware part according to the preamble of claim 1 1 and a method for detecting a cookware part according to the preamble of claim 12.

From DE 199 23 148 A1 discloses a hob with a ceramic cooking surface and four heating zones for setting up each a cookware part is known. The hob also includes a switch disposed beneath the ceramic cooking surface for activating at least one function of the hob, the switch being actuatable by a magnetic force. The switch is a power disconnect switch that disconnects a control unit or a transformer located between the control unit and the power grid from the power grid. The mains disconnect switch is arranged in an edge region of the cooktop and designed as a reed switch. The switching of the reed switch takes place via a magnet arranged above the reed switch on the ceramic cooking surface.

The object of the invention is in particular to make available a magnetic interaction between a set up on a hob surface cookware part and actuated by the magnetic force switch.

The object is achieved by the features of claim 1 and claim 12, while advantageous embodiments and modifications of the invention can be taken from the dependent claims.

The invention relates to a hob with a hob surface, in particular a glass or ceramic cooking surface, with a arranged below the hob surface switch for activating at least one function of the hob, wherein the switch can be actuated by a magnetic force.

It is proposed that the switch is designed to interact magnetically with a cookware part arranged on the hob surface. The inventive arrangement, the switch with a ferromagnetic or permanent nentmagnetischen pot bottom of the cookware part interact and this interaction can be used to automatically trigger a switching process. In particular, when the switch is automatically closed when setting up the cookware part by the magnetic interaction, the switch for producing and disconnecting a network connection of a control unit of the hob can be used. Standby mode can be achieved without any energy consumption. In alternative embodiments of the invention, the switch when setting up the cookware part can also be opened and / or generate a current pulse that can trigger a switching process.

In particular, when the switch is disposed below a heating zone of the cooking surface, the hob can be activated without any further operator intervention by the mere placement of the cookware part.

In principle, the switch can be used to activate and / or deactivate any conceivable function of the hob or a control unit of the hob. In a particularly advantageous embodiment of the invention, the switch activates or deactivates a standby function. When the switch is closed, the standby function is activated, i. the operator can turn on or power a heating zone by operating suitable selector switches. On the other hand, when the switch is open, the control unit is completely turned off and can not receive signals from the selector switches. The selector switches can be designed, for example, as touch-sensitive switching elements.

In this context, the term "heating zone" encompasses all areas of the hob on which cooking utensil parts or their bottoms can be placed.The switch is in particular designed to interact with a cookware element arranged on the hob surface when it is connected to such a cookware element. which preferably has a ferromagnetic or permanent magnetic bottom, which is located on the heating zone, magnetically interacts such that sufficient to actuate or influence the switch sufficient magnetic force is generated.

When the switch is intended to be opened or closed by a magnetic interaction with a cookware part placed on the heating zone. den, can be dispensed with a separate element for generating the necessary magnetic force.

In particular, when the switch is arranged in the center of a heating zone, a short distance between the switch and the Kochgeschirteil can be ensured, resulting in a reliable activation even with inexpensive, relatively small permanent magnets.

A single switch can be used to detect cookware parts on several heating zones when the switch is arranged between at least two heating zones.

A particularly power-saving off-state of the hob, which is also a standby state, can be achieved when a control unit of the hob is connected via the switch to a power supply. A periodic polling of the state of the switch can be avoided, thereby saving power costs. In particular, compared to hobs in which cookware parts are detected by arranged below the cooking surface induction coils, a lower power consumption can be achieved because such cooktops permanently magnetic fields in the coil must generate, which is associated with radiation losses.

In a particularly advantageous embodiment of the invention, the hob is designed as an induction hob, i. it includes at least one arranged below the heating zone induction heating. Although, in principle, an application of the invention in hobs with radiant heaters would be conceivable, in induction cooktops occur, however, especially below the cooking surface significantly lower temperatures. As a result, simple permanent magnets can be used to generate the magnetic force, which are never heated beyond their Curie temperature.

When the hob has a permanent magnet arranged on at least one switching tongue of the switch for generating the magnetic force by interacting with a ferromagnetic bottom of the cookware part, the switch can be safely triggered by any ferromagnetic element. If the switch is very sensitive, triggering the switch would also be kung of the permanent magnet with a paramagnetic element, such as a paramagnetic cookware, conceivable.

Reliable and cost-effective components can be used if the switch is designed as a reed contact. For actuating the switch, for example, a permanent magnet may be arranged in a cookware part.

Sparking and caking of the contacts can be avoided if the switch is arranged in an outer shell filled with shielding gas. The outer shell is best formed from a diamagnetic substance, such as glass.

For example, reed relays can be used. A reed relay is a relay for switching a circuit that works with a reed contact. Reed switching contacts are sealed under vacuum or inert gas in a glass envelope reeds, which also form the contact spring and the armature. The contact tongues are therefore made of noble metal-coated ferromagnetic material (e.g., soft iron). The contact operation is carried out by an externally applied magnetic field, which is generated by a nearby brought permanent magnet or in an associated magnetic coil electrically.

In a further conceivable embodiment of the invention, the switch is designed as a changeover switch.

The magnetic interaction between an element located above the hob surface and the switch is not shielded by the hob surface when the hob surface is made of diamagnetic glass ceramic.

It is also proposed that the switch comprises a resilient tongue with a arranged in the region of the free end of the switching tongue permanent magnet. This makes it possible to dispense with a permanent magnet in the cookware parts, which ultimately all cookware parts, ie in particular pots and pans, can be used for cooking on the hob according to the invention. The invention also relates to a cookware part, in particular a saucepan, a pan or a roasting pan, which has a bottom for placement on a hob.

In order to generate a magnetic force that can be used, for example, to actuate a reed contact, it is proposed that the base comprises a permanent magnet.

Furthermore, the invention relates to a method for detecting a cookware part on a hob.

It is proposed that a state of a magnetic force actuated switch below the hob is used as a parameter for the presence of the cookware part. The magnetic force is thus utilized for the detection of the cookware part and in a resting state, a significant energy saving can be realized in comparison to other methods for detecting a cookware part using induction coils.

Further advantages emerge from the following description of the drawing. In the drawings, embodiments of the invention are shown. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Show it:

Fig. 1 is a schematic representation of a section of a hob before setting up a cookware, Fig. 2 shows the detail of the hob of Figure 1 after setting up a

3 shows a hob with a cookware part according to an alternative embodiment of the invention,

4 is a cooking field with four each one arranged in the center of a heating zone switches in a plan view 5 shows a hob arranged with four each at the edge of a heating zone

Switches in a plan view and Fig. 6 shows a hob according to an alternative embodiment of the invention with a switch arranged between four heating zones in a plan view.

FIG. 1 schematically shows a section of a hob with a rectangular and flat hob surface 10 made of diamagnetic glass ceramic with a plurality of heating zones 12 for setting up a cookware part 18. The heating zones 12 are characterized by induction heating elements 14 arranged below the heating zones 12, which are shown only schematically here , In Figure 1 and below, only one of the heating zones 12 is shown and described to avoid repetition. The further heating zones 12 differ from the heating zone 12 shown in FIG. 1 only in their size and in the maximum output of the induction heating element 14 arranged below the heating zone 12.

The hob also includes, beneath each of the heating zones 12, a switch 16 disposed below the hob surface 10 for activating at least one function of the hob. The switch 16 is actuated by a magnetic force, which will be explained in more detail below. The switches 16 of the different heating zones 12 are connected in parallel and are connected so that a network connection of a control unit not explicitly shown here can be opened and closed by the switches 16, so that the control unit of the hob is connected via the switch 16 to a power supply.

The control unit automatically switches to a standby state when connected to the power supply. This happens as soon as one of the switches 16 is closed. The user recognizes the standby state in that when the standby state is switched on, a warning light is switched on which can be actuated directly via the switch 16. A transformer, which converts a mains voltage into a voltage that can be used by the control unit, can in principle be arranged before or after the switch 16. No-load losses can be avoided if the transformer is arranged after the switch 16, ie between the switch 16 and the control unit. The switch 16 is provided by its structure described below to be opened or closed by a magnetic interaction with a set up on the heating zone 12 cookware 18.

For this purpose, the switch 16 comprises a movable switching tongue 20, which may be suspended resiliently or, as shown in Figure 1, to a support point 28 against the force of a return spring can be rotatably or pivotally mounted. The return spring can be dispensed with if the weight force of the permanent magnet 26 returns the switching tongue 20 to the first position. The switching tongue 20 of the switch 16 comprises a contact region 22, which in a first position of the switching tongue 20 has a distance to a fixed contact 24 of the switch 16 and in a second position of the switching tongue 20 abuts against the fixed contact 24 (Figure 2). The contact area 22 and the fixed contact 24 are coated with precious metal to prevent corrosion. The return spring or gravity, not shown here, drives the switching tongue 20 from the first position to the second position.

At one of the contact region 22 relative to the support point 28 opposite end of the switching tongue 20, this is equipped with a permanent magnet 26. The permanent magnet 26 serves to generate the magnetic force through an interaction with a ferromagnetic bottom 30 of the cookware part 18th

Figure 2 shows the configuration of the switch 16 after setting up a cookware part 18, for example a saucepan or a pan. The cookware part 18 has a bottom 30 made of a ferromagnetic iron-containing material. The ferromagnetic material is magnetized by the magnetic field of the permanent magnet 26 arranged on the switching tongue 20, and a magnetic attraction force is generated between the bottom 30 of the cookware part 18 and the permanent magnet 26. The permanent magnet 26 is moved by the magnetic force in the direction of the bottom 30, ie in the direction of the underside of the hob surface 10, so that a torque is generated on the switching tongue 20. The switching tongue 20 moves driven by the magnetic force acting on the permanent magnet 26 in the second position. As a result, the contact region 22 of the switching tongue 20 and the fixed contact 24 of the switch 16 come to rest, so that the control unit is connected to the power supply and is au- automatically switches to a standby state in which an operator can set a desired heat output of the induction heating elements 14.

The switch 16 shown in Figures 1 and 2 is used by the control unit of a hob according to another embodiment of the invention in a method implemented in the control unit for detecting a cookware part 18 on a hob.

To detect the cookware part 18, the jam unit uses a state of a magnetic force actuatable switch 16 below the hob as a measure of the presence of the cookware part 18. When the switch 16 is closed, the control unit recognizes that a cookware part 18, i. a pot or pan, was placed on the relevant heating zone 12. On the other hand, the control unit recognizes at an interrupted power connection via the switch 16 that there is no pot on the relevant heating zone 12.

FIG. 3 shows a hob with a hob surface 10b and with a cooking utensil part 18b set up on the hob and designed as a saucepan. The cookware part 18b has a permanent magnet 26b incorporated in its bottom 30b. The following description is essentially limited to differences from the embodiment described above. Identical or analogous features are provided with the same reference numerals, wherein for distinguishing the exemplary embodiments, the reference numbers shown in FIG. 3 are provided with the letter b.

Under the hob, a switch 16b is arranged, which is designed as a reed contact. A movable switching tongue 20b of the switch 16b has a noble metal-coated, otherwise formed of ferromagnetic soft iron contact. The switch 16b is arranged in an outer shell 32 filled with shielding gas.

When the cookware part 18b is placed on the hob with the permanent magnet 26b, a magnetic force, an attractive force, acts between the ferromagnetic contact 24b and the permanent magnet 26b, causing the cooker Switch 16b is immediately closed after setting up the cookware part 18b.

FIG. 4 shows a cooking hob according to the invention in a plan view. The hob comprises a flat hob surface 10 with four circular heating zones 12a-12d, under each of which an induction heating element is arranged. In the center of each of the heating zones, a switch 16a - 16d is arranged, which corresponds in terms of operation and structure of the switch 16 of Figure 1. When an operator places a cookware part 18 on one of the heating zones 12a-12d, the corresponding switch 16a-16d is closed by a magnetic interaction with the bottom 30 (FIG. 1) of the cookware part 18. The switches 16a-16d are connected in parallel, so that the hob is always activated when at least one cookware part 18 is on at least one of the heating zones 12a-12d.

FIG. 5 shows an alternative embodiment of the invention in which four switches 16a-16d of the type described in connection with FIG. 1 are each arranged in an edge region of one of four heating zones 12a-12d of a hob. By arranging the switches on the edge of the heating zones 12a-12d, installation space in the center of the heating zones 12a-12d can be saved.

Finally, FIG. 6 shows a further alternative embodiment of the invention, in which a single switch 16 is arranged in the center of the entire hob surface 10, ie between four circular heating zones 12a-12d of the hob. In further embodiments of the invention, the switch 16 can also be arranged between two or three heating zones. Further, it would be conceivable to enhance the magnetic interaction between the cookware part 18 and the switch 16 by a metal element with high magnetic conductivity. reference numeral

10 hob area

12 heating zone

14 induction heating element

16 switches

18 cookware part

20 tongue

22 contact area

24 contact

26 permanent magnet

28 point of support

30 floor

32 outer shell

Claims

claims

A hob with a hob surface (10) for mounting a cookware part (18) and a switch (16) disposed below the hob surface (10) for activating at least one function of the hob, the switch (16) being actuable by a magnetic force , characterized in that the switch (16) is adapted to interact magnetically with a cookware part (18) arranged on the cooking surface (10).

2. Hob according to claim 1, characterized in that the switch (16) is provided to be opened or closed by a magnetic interaction with a on the cooking surface (10) set up cookware part (18).

3. Hob according to one of the preceding claims, characterized in that the switch (16) in the center of a heating zone (12) of the hob surface (10) is arranged.

4. Hob according to one of claims 1 and 2, characterized in that the switch (16) between at least two heating zones of the hob surface (10) is arranged.

5. Hob according to one of the preceding claims, characterized marked, that a control unit of the hob via the switch (16) with a

Power is connected.

6. Hob according to one of the preceding claims, characterized by at least one below a heating zone (12) of the cooking surface (18) arranged ted induction heating element (14).

7. Hob according to one of the preceding claims, characterized by a on at least one switching tongue (20) of the switch (16) arranged permanent magnet (26) for generating the magnetic force by an interaction with a ferromagnetic bottom (30) of the cookware part (18).

8. Hob according to one of the preceding claims, characterized in that the switch (16) is designed as a reed contact.

9. Hob according to one of the preceding claims, characterized marked, that the switch (16) is arranged in an outer shell (32) filled with protective gas.

10. Hob according to one of the preceding claims, characterized in that the hob surface (10) is made of diamagnetic glass ceramic.

1 1. Cookware part having a bottom (30b) for placement on a hob, characterized by a in the bottom (30b) incorporated permanent magnet (26b).

12. A method for detecting a cookware part (18) on a hob, characterized in that a state of a switch actuatable by a magnetic force (16) below the hob as a parameter for the presence of the cookware part (18) is used.