DE102018219740A1 - Cooking appliance with a radiant heater and a sensor module with at least one temperature sensor and a separate occupancy detection sensor - Google Patents

Abstract

One aspect relates to a cooking appliance (1) with a cooking appliance plate (2) on which a preparation vessel for preparing food to be cooked can be set up, with at least one radiant heater (8, 9, 10, 11) which is arranged under the cooking appliance plate (2) and is arranged for delivering thermal energy to the cooking appliance plate (2) and with a sensor device (17) which has a temperature sensor (19, 21), the sensor device (17) having a sensor module (18) which has at least one temperature sensor (19 , 21) and a separate occupancy detection sensor (22) for detecting a state of the preparation vessel set up on the cooking appliance plate (2).

Description

One aspect of the invention relates to a cooking appliance with a cooking appliance plate on which a preparation vessel for preparing food to be cooked can be set up. The cooking appliance also has at least one radiant heater which is arranged under the cooking appliance plate and which is arranged to emit thermal energy to the cooking appliance plate. The cooking appliance also has a sensor device which has a temperature sensor.

Such a design of a cooking device is for example from the DE 10 2006 010 107 A1 known.

Furthermore, from the WO 2008/117910 A1 an embodiment of the cooking device is known, in which a temperature sensor and a radiant heater are present and the temperature sensor is designed for temperature detection of the heating coil of the radiant heater, and can also recognize via temperature information whether a saucepan is placed on the cooking device or not. Such a multifunctional sensor is of compact design, but is limited in terms of measurement accuracy. This means that neither the occupancy can be exactly recognized, nor the temperature can be recorded exactly. Among other things, this can lead to the fact that a cooking appliance plate, on which the thermal energy of the radiant heater acts, can overheat and be damaged as a result.

It is an object of the present invention to provide a cooking device in which both temperature detection and occupancy detection of a cooking device plate with a preparation vessel are improved.

This object is achieved by a cooking appliance which has the features of claim 1.

One aspect of the invention relates to a with a cooking appliance plate. A preparation vessel for cooking food can be placed on the cooking plate. The preparation vessel can be, for example, a saucepan or a pan or the like. The cooking appliance has at least one radiant heater. The radiant heater is arranged under the cooking appliance plate and arranged to give off heat energy to the cooking appliance plate. The cooking appliance also has a sensor device which has a temperature sensor. The sensor device has a sensor module which has at least one temperature sensor and an occupancy detection sensor which is arranged at a spacing and is separate from the temperature sensor for detecting a state of the preparation vessel set up on the cooking appliance plate. Such a configuration with a temperature sensor and an occupancy detection sensor separate therefrom, which is thus a further sensor independent of the temperature sensor, on the one hand enables the temperature to be detected independently of the occupancy detection and also to be more precise. On the other hand, this configuration also enables the occupancy detection to be made independent of the temperature detection and also enables this occupancy detection to be made more precise. In addition, however, it is provided that these two functional and separate different sensors are nevertheless arranged in one sensor module and can therefore also be arranged as required by positioning this module accordingly.

In particular, it is provided that the sensor module is designed as one part. This is a further advantageous embodiment, since the sensor device can then also be made compact and these different sensors, namely the temperature sensor and the occupancy detection sensor, are present in this one sensor module. They are therefore not considered in their own module or basically only as their own sensors, but are installed in this sensor module.

Since this one-piece sensor module is then already manufactured and provided as a prefabricated structural unit, it can be easily installed on the cooking appliance, in particular on the radiant heater. This also maintains the positional arrangement between the temperature sensor and the occupancy detection sensor, which are each arranged in a fixed manner in the sensor module relative to one another and in particular at a distance from one another. Individual assemblies, on the one hand of the temperature sensor and on the other hand of the occupancy detection sensor on the radiant heater are then no longer necessary. This sensor module also saves assembly effort and even after the sensor module has been installed, the previously desired and defined positioning of the temperature sensor and the occupancy detection sensor relative to one another is maintained.

It is preferably provided that the sensor module is rod-shaped or rod-like. This creates an elongated construction, which on the one hand is then relatively narrow, and on the other hand enables the aforementioned sensors to be positioned individually along this longitudinal axis of this rod. This also allows a defined position specification of the individual sensors relative to individual components of the Radiant heater, such as a heating coil, are defined. Due to this specific geometry of the sensor module, for example, a heating coil of the radiant heater is not covered from the top by the sensor module and is therefore only slightly covered due to the relatively narrow rod shape. The thermal energy generated by the heating coil can thus reach the cooking appliance plate practically without restriction, since the sensor module, viewed in the vertical direction, is arranged between this heating coil and the cooking device plate.

It is preferably provided that the sensor module has a first temperature sensor and a separate and locally spaced second temperature sensor. For such a configuration with at least three separate sensors, namely two temperature sensors and one occupancy detection sensor, the temperature detection can be carried out more precisely, in particular also more locally. Irrespective of this, the occupancy detection can take place separately. With these at least two temperature sensors, the temperature can be recorded at different locations and used as a basis for further evaluations.

It is preferably provided that the two temperature sensors and the occupancy detection sensor are arranged in a row with respect to one another in the sensor module. As a result, individual information can be tapped or recorded at different points, namely, on the one hand, a temperature, on the other hand, a possible assignment of the cooking appliance plate to a preparation vessel.

In particular, it is provided that the occupancy detection sensor is arranged between the first temperature sensor and the second temperature sensor and is arranged at a distance from both temperature sensors. As a result, the spacing between the two temperature sensors is made relatively large, so that temperatures can be recorded at defined different points at which different temperatures also prevail during operation of the cooking device. Nevertheless, the area between the two temperature sensors is used, namely for the occupancy detection sensor to be arranged there. As a result, the length of the sensor module can be made compact, since a preferably provided distance between the two temperature sensors and thus a preferably desired distance in this respect is used, so that the occupancy detection sensor is installed in between.

It is preferably provided that the sensor module is arranged with its longitudinal axis in the radial direction of the radiant heater and the first temperature sensor is arranged radially further inside than the occupancy detection sensor, and the second temperature sensor is arranged radially further outside than the occupancy detection sensor. In addition or instead of this, it can be provided that the first temperature sensor is arranged radially further inwards than the second temperature sensor.

It is preferably provided that the radiant heater has a radiator pot and at least one heating coil arranged therein. When looking at a projection in the direction of a longitudinal axis of the radiant heater, the temperature sensor and the occupancy detection sensor are arranged within the area which is delimited by the heating coil. In particular, the first temperature sensor, the second temperature sensor and the occupancy detection sensor are arranged within this area when viewed in this way. It is preferably provided that when the projection is viewed in the direction of the longitudinal axis of the radiant heater, the first temperature sensor is arranged essentially at the center of this surface area, which is delimited by the heater body, and / or the second temperature sensor is arranged at an edge area of this surface area. In particular, it is possible that the temperature of the cooking appliance plate is detected with the first temperature sensor. In particular, the first temperature sensor is connected in such a way that it detects this temperature very precisely.

It is advantageously provided that a control unit, in particular power electronics, of the cooking appliance evaluates this temperature information and, when a temperature value that is detected by the first temperature sensor exceeds a temperature threshold value, the radiant heater is switched off. If this limit value is thus exceeded or reached, the radiant heater in particular is switched off or its output is reduced.

In contrast, the second temperature sensor, which is preferably present, is not arranged centrally but rather decentrally, so that it is little influenced by the thermal energy of the heating coil, in particular in comparison to the first temperature sensor. As a result, the second temperature sensor enables the temperature of a preparation vessel to be detected. In this context, it is also suitable as a sensor for setting the temperature of the food to be cooked or the food to be fried.

The occupancy detection sensor is advantageously designed as a capacitive sensor. In this connection, the capacitive sensor can be formed with two conductive metal plates, it can be recognized on the basis of this configuration whether a metallic preparation vessel is positioned on the cooking appliance plate or not. This occupancy detection can also be used to operate the radiant heater individually, for example to switch off the heating power when it is recognized that no preparation vessel is arranged on the cooking appliance plate. In addition, this information of the occupancy detection can also be used, for example, to issue a warning signal when the cooking plate in the area of a cooking zone that is heated by the radiant heater is still hot, but no preparation vessel has been placed on this cooking zone on the cooking plate.

In terms of circuitry, the capacitive sensor is preferably designed as a series resonance system. Capacities between the sensor module and a preparation vessel are very small and this results in malfunctions, tolerances and drifts etc. which also have a greater impact and could lead to errors in occupancy detection. This can be prevented by the design as a series resonance system. In connection with two capacitances, an inductance forms a series resonance circuit, the properties of which depend on whether or not a preparation vessel on the cooking appliance plate and in particular the cooking zone, which is monitored by the sensor module and is heated by the associated radiant heater. In addition to the series resonance system, the capacitive sensor preferably has a measuring unit with which the series resonance system is evaluated. This measuring unit determines the properties of the series resonance system or the series resonance circuit, for example the resonance frequency. A signal can be generated from this, which characterizes the occupancy detection.

The system may only be susceptible to unknown parasitic (interference) capacitances at the connection between the inductance and the capacitance connected in series. There, a parasitic capacitance could also have a greater impact on the resonance properties. On the connecting line between the inductance and the measuring unit, however, the series resonance system is insensitive to parasitic capacitances if the measuring frequency is close to the resonance frequency. This is particularly the case because the series resonance system has a low resistance in this regard.

In the advantageous circuit of this capacitive sensor, the measuring electrodes, which are each formed by a capacitor plate of the two capacitors, are arranged on the sensor module and the inductance is also part of the sensor module. As a result, the sensitive connection between the inductance and the capacitance connected in series can be kept very short and therefore insensitive to interference. A high temperature is to be expected in the sensor module due to the proximity to the heating coil, as a result of which the configuration and positioning at this point in the form of a semiconductor component could be disadvantageous. In contrast, the inductance is passive and can be designed to be resistant to high temperatures.

The measuring unit is less suitable for high temperatures due to the semiconductor elements installed therein and is therefore preferably not installed in the sensor module itself or not integrated there. It is preferably provided that this measuring unit is arranged externally to the sensor module and is connected to the sensor module via electrical connections, in particular connecting cables. Since such cables also bring a relatively large and also not exactly predictable parasitic capacitance into the system of the capacitive sensor, the above-mentioned configuration of the series resonance system also has significant advantages in this regard.

Since it can also be provided in one embodiment that the sensor module is arranged close to the heating coil of the radiant heater, adequate insulation of the measuring unit from the heating coil is also advantageous. It is particularly advantageous if the measurement signals are processed, for example, in a SELV circuit. In the case of the capacitive sensor, as can advantageously be designed according to the above explanation, this is possible through additional capacitances. One of these additional capacitances can be connected in series with the inductance and the other capacitance already connected in series. The additional additional capacity can be provided in series with the existing other capacity. These two further capacitances enable adequate protection to be provided in the event of a fault, particularly in the event of a connection between the measuring unit and the heating coil, and the voltage that occurs is not transmitted to the measuring unit. In particular, if these two further capacities are larger, in particular significantly larger than the capacities of the series resonance system that are basically present, the influence of the two further capacities on the resonance properties of the series resonance system has no effect or at most so that they are negligible.

In particular, provision can be made for the sensor module to provide recorded temperature information which can also serve as an input variable for regulating the temperature of the food. In particular, by specifically switching off the sensors towards the heating coil of the radiant heater, they can also do better be protected and an improved structure of the sensor module is possible. In addition, it is possible that this additional information about the thermal conditions of the system comprising the radiant heater, the cooking appliance plate and a preparation vessel can improve a heating profile and thus a time course of heating. In this way, for example, the parboiling times can also be carried out more appropriately.

The cooking appliance is preferably a hob and the cooking appliance plate is a hob plate. With this hob, one or more cooking zones can be formed, on which a preparation vessel for preparing food can be placed. A radiant heater is arranged underneath such a cooking zone, so that thermal energy can be transferred to the cooking appliance plate in the region of the cooking zone by the operation of the radiation heating element and the surface area of the cooking zone of this cooking appliance plate is thereby heated.

With information such as "top", "bottom", "front", "rear," horizontal "," vertical "," depth direction "," width direction "," height direction "and the like, those are given for the intended use and arrangement of the cooking appliance Positions and orientations given.

The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the combination indicated in each case, but also in other combinations or on their own, without the scope of Leaving invention. Embodiments are thus also to be regarded and encompassed by the invention, which are not explicitly shown or explained in the figures, but which emerge and can be generated from the explained embodiments by separate combinations of features. Designs and combinations of features that do not have all the features of an originally formulated independent claim are therefore also to be regarded as disclosed. In addition, versions and combinations of features, in particular those explained above, are to be regarded as disclosed which go beyond or differ from the combinations of features set out in the references of the claims.

• 1 eine schematische Schnittdarstellung eines Ausführungsbeispiels eines Gargeräts;
• 2 eine vereinfachte Draufsichtdarstellung auf einen Strahlungsheizkörper und ein Sensormodul mit Temperatursensoren und einem Belegungserkennungssensor;
• 3 das Sensormodul in 2 in einer Seitenansicht; und
• 4 eine Darstellung eines Ausführungsbeispiels einer Schaltung eines als kapazitiven Sensor ausgebildeten Belegungserkennungssensor des Sensormoduls gemäß 3

Exemplary embodiments of the invention are explained in more detail below with the aid of schematic drawings. Show:

• 1 is a schematic sectional view of an embodiment of a cooking device;
• 2nd a simplified top view of a radiant heater and a sensor module with temperature sensors and an occupancy detection sensor;
• 3rd the sensor module in 2nd in a side view; and
• 4th a representation of an embodiment of a circuit of a configured as a capacitive sensor detection sensor of the sensor module according to 3rd

In the figures, identical or functionally identical elements are provided with the same reference symbols.

In 1 is shown in a schematic representation of an embodiment of a cooking device, which here is a hob 1 is. However, the cooking device can also be, for example, an oven, in particular with a hob.

The stove top 1 has a cooktop 2nd on, which represents a cooking appliance plate in the exemplary embodiment. On a top 3rd the cooktop 2nd In the exemplary embodiment, the number, size and position of the cooking zones are only examples 4th , 5 , 6 and 7 trained or identified. On these cooking zones 4th to 7 For example, a preparation vessel, such as a pan or a pot, can be set up in order to be heated and to be able to prepare items to be cooked which have been introduced into the preparation vessel.

The stove top 1 has a heating unit, in particular a radiant heater 8th , a radiant heater 9 , a radiant heater 10th and a radiant heater 11 on that zonal in the area of the cooking zones 4th to 7 below the hob 2nd are arranged.

The stove top 1 also has an operating and display device 12 on.

In 3rd is a top view of a radiant heater 8th shown. This radiant heater 8th has a radiator pot 13 on. This radiator pot 13 has a pot bottom 14 and a peripheral web or a boundary wall 15 on. In the bottom of the pot 14 is at least a heating coil 16 of the radiant heater 8th relocated. In addition, in 2nd a sensor device 17th the hob 1 shown. The sensor device 17th is as a sensor module 18th educated. The sensor module 18th has a first temperature sensor 19th on. This first temperature sensor 19th is here in a front area, especially a front tip 20th this sensor module 18th arranged. The sensor module 18th is formed as a part. The sensor module 18th is preferably designed as a pin-like component or rod-shaped. The sensor module 18th also points to the first temperature sensor 19th separate second temperature sensor 21st on. The second temperature sensor 21st is spaced from the first temperature sensor 19th arranged. In addition, the sensor module 18th an occupancy detection sensor 22 on. This occupancy detection sensor 22 is to the temperature sensors 19th and 21st separately and also at a distance from these two temperature sensors 19th , 21st arranged. In particular, these are at least three sensors 19th , 21st , 22 in the direction of a longitudinal axis A of the sensor module 18th considered arranged in a row to each other. The occupancy detection sensor 22 is viewed in this row between the first temperature sensor 19th and the second temperature sensor 21st arranged. As can be seen, is the radiant heater 8th formed with a round geometry in plan view. The sensor module 18th is in the radial direction to a center point M oriented to this round geometry. The sensor module 18th viewed in this radial direction, extends over the entire radius length, the radius extending from the center M up to the outer edge of the boundary wall 15 measured. When looking at a projection in the direction of a longitudinal axis B of the radiant heater 8th is the first temperature sensor 19th , the occupancy detection sensor 22 and in particular the second temperature sensor 21st arranged within the area by the heating coil 16 is limited. This longitudinal axis of the radiant heater 8th is in the representation in 2nd oriented perpendicular to the plane of the figure and through the center M fading.

When looking at the projection in the direction of this longitudinal axis B of the radiant heater 8th is the first temperature sensor 19th in an advantageous embodiment essentially at the center M of the area covered by the radiator pot 13 is limited. In addition or instead of this is the second temperature sensor 21st at an edge area viewed in the radial direction 23 this area 24th arranged.

The sensor module 18th is via at least one connection line 25th with a control unit of the cooking device or the hob 1 connected.

As in the illustration in 3rd the sensor module shows 18th a carrier 26 on top of it 27th the first temperature sensor 19th , the occupancy detection sensor 22 and the second temperature sensor 21st are arranged. This arrangement also provides some protection against the heating coil 16 enables.

In particular, the occupancy detection sensor 22 a capacitive sensor. With the first temperature sensor 19th in particular the temperature of the hob plate 2nd detected. With the second temperature sensor 21st the temperature of a preparation vessel is recorded.

In 4th is an exemplary circuit of a capacitive sensor 22 shown. In particular, this capacitive sensor 22 a series resonance system with inductance L1 and the capacities C1 and C2 on. The capacities C1 and C2 are not physical components, but the upper electrodes of the two capacitors C1 and C2 symbolize a preparation vessel here. The inductance L1 and the capacity C2 are connected in series. Through the additional capacities C3 and C4 can isolate the measurement signals from the heating coil 16 be made possible. In the context is the capacity C3 in line to the capacity C2 and inductance L1 switched. The further capacity C4 is in line with capacity C1 switched. If the other capacities C3 and C4 are larger than the capacities C1 and C2 affects the influence of C3 and C4 practically not based on the resonance properties of the system.

In addition, the circuit has a measuring unit 28 with which the series resonance system, comprising the inductance L1 and at least the capacities C1 and C2 , evaluates.

Reference symbol list

1

Cooking appliance

2nd

Cooking appliance plate

3rd

Top

4th

Cooking zones

5

Cooking zones

6

Cooking zones

7

Cooking zones

8th

Radiant heater

9

Radiant heater

10th

Radiant heater

11

Radiant heater

12

Operating and display device

13

Radiator pot

14

Pot bottom

15

Boundary wall

16

Heating coil

17th

Sensor device

18th

Sensor module

19th

Temperature sensor

20th

top

21st

Temperature sensor

22

Occupancy detection sensor

23

Edge area

24th

Area

25th

Measuring unit / connecting cable

26

carrier

27th

Top

28

Unit of measurement

A

Longitudinal axis

B

Longitudinal axis

C1 - C4

capacities

L1

Inductance

M

Focus

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102006010107 A1 [0002]
• WO 2008/117910 A1 [0003]

Claims (11)

Cooking appliance (1) with a cooking appliance plate (2) on which a preparation vessel for preparing food to be cooked can be set up, with at least one radiant heater (8, 9, 10, 11) which is arranged under the cooking appliance plate (2) and for emitting thermal energy is arranged on the cooking appliance plate (2) and with a sensor device (17) which has a temperature sensor (19, 21), characterized in that the sensor device (17) has a sensor module (18) which has at least one temperature sensor (19, 21) and a separate occupancy detection sensor (22) for detecting a state of the preparation vessel set up on the cooking appliance plate (2). Cooking appliance (1) after Claim 1 , characterized in that the sensor module (18) is formed as a part. Cooking appliance (1) after Claim 1 or 2nd , characterized in that the sensor module (18) is rod-shaped. Cooking appliance (1) according to one of the preceding claims, characterized in that the sensor module (18) has a first temperature sensor (19) and a separate and spatially spaced second temperature sensor (21). Cooking appliance (1) after Claim 4 , characterized in that the two temperature sensors (19, 21) and the occupancy detection sensor (22) are arranged in a row to one another in the sensor module (18). Cooking appliance (1) after Claim 4 or 5 , characterized in that the occupancy detection sensor (22) is arranged between the first temperature sensor (19) and the second temperature sensor (21). Cooking appliance (1) according to one of the preceding Claims 4 to 6 , characterized in that the sensor module (18) is arranged with its longitudinal axis (A) in the radial direction of the radiant heater (8, 9, 10, 11), and the first temperature sensor (19) is arranged radially further inward than the occupancy detection sensor ( 22) and the second temperature sensor (21) is arranged radially further outside than the occupancy detection sensor (22), and / or the first temperature sensor (19) is arranged radially further inside than the second temperature sensor (21). Cooking appliance (1) according to one of the preceding claims, characterized in that the radiant heater (8, 9, 10, 11) has a radiator pot (13) and at least one heating coil (16) arranged therein, with a projection in the direction of a longitudinal axis ( B) of the radiant heater (8, 9, 10, 11), the temperature sensor (19, 21) and the occupancy detection sensor (22) are arranged within the surface area (24) which is delimited by the heating coil (16), in particular the first temperature sensor ( 19), the second temperature sensor (21) and the occupancy detection sensor (22) are arranged within this surface area (24). Cooking appliance (1) according to one of the preceding Claims 4 to 7 and after Claim 8 , characterized in that when the projection is viewed in the direction of the longitudinal axis (B) of the radiant heater (8, 9, 10, 11), the first temperature sensor (19) essentially at the center (M) of the surface area (24) which is caused by the heating coil ( 16) is arranged, and / or the second temperature sensor (21) is arranged on an edge region (23) of this surface region (24). Cooking appliance (1) according to one of the preceding claims, characterized in that the occupancy detection sensor (22) is a capacitive sensor. Cooking appliance (1) after Claim 10 , characterized in that the capacitive sensor is designed in terms of circuitry as a series resonance system (L1, C1, C2), and the capacitive sensor has, in addition to the series resonance system (L1, C1, C2), a measuring unit (25) with which the series resonance system (L1, C1 , C2) is evaluated.

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