Control device for a cooking appliance

Abstract

 Control device for a cooking appliance, the cooking appliance comprising a glass-ceramic hob, at least one radiant heater that is disposed beneath the glass-ceramic hob and which defines a respective cooking area on said glass-ceramic hob and a support that is disposed on the glass-ceramic hob at a certain distance in relation to said glass-ceramic hob, and the control device comprising absence detection means for detecting the absence of a cooking vessel supported on the corresponding cooking area. Absence detection means are disposed on the support and comprise at least one optical receiver that receives an optical radiation emitted by the radiant heater when said radiant heater is switched on and in the absence of the cooking vessel on the cooking area associated to said switched-on radiant heater, said optical receiver being connected to a first control unit of the control device disposed on the support.

Description

TECHNICAL FIELD

[0001] The present invention relates to a control device adapted to a cooking appliance, said control device comprising means for detecting the absence of a cooking vessel on a switched-on radiant heater on said cooking appliance.

PRIOR ART

[0002] There are known cooking appliances, especially glass-ceramic ones, which include radiant heaters, a glass-ceramic hob disposed on said radiant heaters, and devices for detecting the presence of a cooking vessel on said glass-ceramic hob in order to automatically switching off the cooking appliance in the event that they do not detect the cooking vessel on the switched-on radiant heater. This thus reduces the energy consumed by the cooking appliance, enables the power of the heater to be regulated in accordance with the area of the heater covered by the cooking vessel and also prevents the risk of accidents.

[0003] The presence detector devices are essentially based on mechanical, capacitive, resistive, optical or inductive sensors, among others, which are disposed on the glass-ceramic hob.

[0004] EP 1137323 A describes an electronic circuit that includes an inductive-type sensor for the presence detection of a metallic vessel on a cooking area on the glass-ceramic hob. The sensor includes a single conductor loop that is superimposed to the heating resistances of the cooking heaters, a magnetic field being generated by the sensor loop itself, while the high-frequency electric current for the generation of said magnetic field originates from a micro-processor that extracts trains of pulses from the generator circuit to prevent electromagnetic disturbances. The proximity of the metallic vessel is measured through the variation of the voltage at the ends of the loop, this being due to the Eddy currents induced in the metallic vessel, which cause a reduction in the inductance of the sensor loop.

[0005] US 4319109 B describes detection devices that include a plurality of inductive sensors disposed radially on a radiant-type cooking heater. Said sensors react when they are covered, with the result that they also detect the sizes of the cooking vessels that are disposed on them. As a result, if the cooking vessel is small, it will be detected by the sensors closest to the centre of the radiant heater, whereas if the vessel is large, it will be detected by the sensors around the outside.

[0006] Finally, DE 10242099 A discloses a cooking appliance that comprises a glass-ceramic hob with at least one lower surface upon which the cooking vessel is supported, an upper surface disposed at a certain height in relation to the lower surface, and a substantially vertical transition surface that links the lower surface to the upper one, with the result that the detection device includes an infrared emitter and an infrared detector, both inserted on the transition surface. The emitter and the receiver may be disposed facing each other, in which case the presence of the cooking vessel on the corresponding lower surface is detected when the receiver is not able to receive the radiation emitted by the emitter. In other cases, the emitter and the receiver may be disposed adjacent to each other so that the presence of the cooking vessel is detected when the receiver receives the radiation emitted by the emitter, given that in this case said radiation is reflected by the cooking vessel towards the receiver, as a result of which it is necessary that said cooking vessel is coated with a material that enables the reflection of the infrared radiation.

DISCLOSURE OF THE INVENTION

[0007] The object of this invention is to provide a control device for a cooking appliance according to the claims.

[0008] The cooking appliance comprises a glass-ceramic hob, at least one radiant heater that is disposed beneath said glass-ceramic hob and which defines a respective cooking area on said glass-ceramic hob, and a support that is disposed at a certain distance on the glass-ceramic hob. In addition, the control device comprises a first control unit disposed on the support, and absence detection means that detect the absence of a cooking vessel supported on the cooking area corresponding to the radiant heater that is switched on.

[0009] The absence-detection means comprise at least one optical receiver that is disposed on the support and not on the glass-ceramic hob, with the result that as it is not necessary to adapt said glass-ceramic hob, as is the case in other known solutions, the absence-detection means may easily be adapted to any existing glass-ceramic hob arrangement.

[0010] In addition, the absence-detection means included in the control device do not include a specific additional optical emitter inserted on or beneath the glass-ceramic hob or in auxiliary members disposed supported on said glass-ceramic hob. Rather, it is the radiant heater that acts as an optical emitter, with the result that the optical receiver receives the optical radiation emitted by said radiant heater when it is switched on and in the absence of the cooking vesselon the cooking area associated with said switched-on radiant heater.

[0011] These and other advantages and characteristics of the invention will be made evident in the light of the drawings and the detailed description thereof.

DESCRIPTION OF THE DRAWINGS

[0012] 

Figure 1 is a schematic view in perspective of a cooking appliance that comprises a first embodiment of a control device according to the invention that includes means for detecting the absence of a cooking vessel on a switched-on radiant heater.

Figure 2 is a schematic cross-section of the cooking appliance of Figure 1.

Figure 3 is a schematic view in perspective of the cooking appliance of Figure 1 wherein the control device comprises safety means for switching off the switched-on radiant heater.

Figure 4 is a schematic view in perspective of the cooking appliance of Figure 1 wherein the control device comprises means for controlling the absence-detection means of the cooking vessel.

Figure 5 is a schematic view in perspective of the cooking appliance that comprises a second embodiment of the control device according to the invention.

Figure 6 is a schematic cross-section of the cooking appliance of Figure 5.

DETAILED DISCLOSURE OF THE INVENTION

[0013] With reference to figures 1 to 6, a control device for a cooking appliance 1 according to the invention comprises a first control unit 11, absence detection means 2 for detecting the absence of a cooking vessel 4, said cooking vessel being any type of cooking vessel. The cooking appliance comprises radiant heaters 5 that are disposed beneath said glass-ceramic hob 3 and which define respective cooking areas 5b on said glass-ceramic hob 3, and a support 7b that is disposed at a certain distance on the glass-ceramic hob 3, with the result that the absence-detection means 2 detect the absence of the cooking vessel 4 on the cooking area 5b corresponding to the radiant heater 5 that is switched on.

[0014] The absence detection means 2 comprise at least one optical receiver 6 that is disposed on the support 7b and detects an optical radiation emitted by the corresponding radiant heater 5 when said radiant heater 5 is switched on and in the absence of the cooking vessel 4 on the cooking area 5b associated with said radiant heater 5, said optical receiver 6 being connected to the first control unit 11 that is disposed on the support 7b. Said optical receiver 6 is a photodetector capable of detecting optical radiations originating from the various cooking areas 5b, said radiations being those corresponding to spectral bands that are situated in visible and/or infrared spectrums.

[0015] In the first embodiment of the invention, shown in figures 1 to 4, the absence-detection means 2 comprise a single optical receiver 6 that has a broad viewing angle, preferably of +/- 65°, and which is disposed inserted into the support 7b, with said support 7b being disposed substantially parallel to and opposite the glass-ceramic hob 3. The optical receiver 6 is disposed focused in relation to the cooking areas 5b of the glass-ceramic hob 3, with the result that said cooking areas 5b are inside the field of vision of the optical receiver 6. As it is not necessary to adapt the glass-ceramic hob 3, said absence detection means 2 may be used in any existing glass-ceramic hob 3 arrangements.

[0016] When at least one of the radiant heaters 5 is switched on and the cooking vessel 4 is not positioned on the cooking area 5b associated with said radiant heater 5, the optical receiver 6 receives the optical radiations originating from said cooking area 5b, detecting the absence of the cooking vessel 4 in this way. If, on the other hand, the cooking vessel 4 is supported on the cooking area 5b associated with the radiant heater 5, said cooking vessel 4 prevents the optical radiations from reaching the optical receiver 6.

[0017] In addition, the control device of the invention includes warning means 10, disposed on the support 7b, which are connected to the first control unit 11 and include light and/or sound devices. As a result, when the optical receiver 6 provides an electrical signal as a response to the radiation originating from the switched-on radiant heater 5, the first control unit 11 activates the warning means 10 which warn the user, by means of a light and/or sound signal, that there is a switched-on radiant heater 5 without the cooking vessel 4 being supported on the cooking area 5b associated with said switched-on radiant heater 5.

[0018] In the event that there is bidirectional communication between the extractor hood 7 and the glass-ceramic hob 3, the warning means 10 may be disposed on said glass-ceramic hob 3.

[0019] Furthermore, the control device may include, as shown in Figure 3, safety means 18 for switching off the switched-on radiant heater 5 in the absence of the cooking vessel 4, which include a first emitter 13 inserted into the support 7b of the extractor hood 7 and connected to the first control unit 11, and a first receiver 14 disposed on or beneath the glass-ceramic hob 3, outside the cooking areas 5b, and connected at the same time to a second control unit 12 of said control device, disposed on or beneath the glass-ceramic hob 3, which controls the radiant heaters 5. As a result, when the optical receiver 6 provides an electrical signal, as a response to the incidental optical radiation originating from the switched-on radiant heater 5, the first control unit 11 sends a control command to the first emitter 13 for it to switch off, after a preset safety time, the corresponding radiant heater 5, said control command being transmitted to the first receiver 14 by means of a short-range communication. Said first receiver 14 sends the control command to the second control unit 12, which executes the command to switch off the corresponding radiant heater 5, emitted from the extractor hood 7.

[0020] The control device of the invention may combine the warning means 10 with the safety means 18, with the result that if the optical receiver 6 detects the absence of the cooking vessel 4 on the corresponding cooking area 5b, it sends the electrical signal to the first control unit 11, with the warning means 10 being activated first of all. If after a preset safety time, the user does not change the situation, either by placing the cooking vessel 4 on the cooking area 5b associated with the switched-on radiant heater 5, or by switching off said radiant heater 5 manually, the first control unit 11 sends the first emitter 13 a control command to switch it off, the control command being transmitted to the second control unit 12 by means of the short-range communication.

[0021] The first control unit 11 may store information about the characteristics of the optical radiations emitted by the radiant heaters 5, with the result that it may detect false alarms corresponding to another type of radiation that the optical receiver 6 may pick up, and not act on said false alarms.

[0022] In addition, the control device may include, as shown in Figure 4, means 15 for supervising that the absence detection means 2 operate correctly, said supervision means 15 comprising a second receiver 16 inserted into the support 7b of the extractor hood 7 and connected to the first control unit 11, and a second emitter 17 disposed on or beneath the glass-ceramic hob 3, outside the cooking areas 5b, and connected at the same time to the second control unit 12. As a result, the radiant heater 5 that is switched on sends to the first control unit 11, by means of a short-range communication and through the second emitter 17, an information referring to the condition and the power level of said radiant heater 5. The first control unit 11 stores the values of the theoretical optical radiation corresponding to each power level of the switched-on radiant heater 5, with the result that if the level of optical radiation picked up by the optical receiver 6 does not correspond with the theoretical level of radiation corresponding to the power level of the switched-on radiant heater 5, the first control unit 11 sends a signal to the warning means 10, which warn the user of a malfunction of the absence detection means 2.

[0023] In the event that the cooking appliance includes supervision means 15 and safety means 18, the first emitter 13 and the second receiver 16 may be replaced by a first emitter/receiver device, and the second emitter 17 and the first receiver 14 may be replaced by a second emitter/receiver device, with the result that it uses a single short-range communication channel.

[0024] In a second embodiment of the invention shown in figures 5 and 6, the extractor hood 7 includes a number of optical receivers 6 on the support 7b, one for each cooking area 5b, with the result that each optical receiver 6 is disposed focused in relation to the corresponding cooking area 5b, thus picking up the optical radiation originating from the corresponding radiant heater 5. In this second embodiment, the optical receiver 6 has a smaller viewing angle than in the previous embodiment, preferably of +/-10°. In the second embodiment, the control device includes the warning means 10, which are connected to the first control unit 11 and include light and/or sound devices. As a result, when the corresponding optical receiver 6 provides an electrical signal as a response to the radiation originating from the switched-on radiant heater 5, the first control unit 11 activates the warning means 10, which warn the user, by means of a light and/or sound signal, that there is a switched-on radiant heater 5 without a cooking vessel 4 supported on the cooking area 5b associated with said radiant heater 5. Finally, the control device may include safety means and/or the supervision means, not shown in the figures.

[0025] In other embodiments, not shown in the figures, the extractor hood 7 may include a number of optical receivers 6 with angles of view between those used in the first embodiment and the second embodiment, with the result that each optical receiver 6 may pick up the radiation of a number of radiant emitters 5. In addition, the support 7b is disposed opposite on the glass-ceramic hob at a certain distance, there being no need for it to be inserted into the extractor hood 7, as it may be built into the support 7b, for example, in a kitchen unit.

Claims

1. Control device for a cooking appliance, said cooking appliance (1) comprising a glass-ceramic hob (3), at least one radiant heater (5) that is disposed beneath said glass-ceramic hob (3) and which defines a respective cooking area (5b) on said glass-ceramic hob (3) and a support (7b) that is disposed on the glass-ceramic hob (3) at a certain distance in relation to said glass-ceramic hob (3), and said control device comprising absence detection means (2) for detecting the absence of a cooking vessel (4) supported on the corresponding cooking area (5b), characterised in that the absence detection means (2) are disposed on the support (7b) and comprise at least one optical receiver (6) that receives an optical radiation emitted by the radiant heater (5) when said radiant heater (5) is switched on and in the absence of the cooking vessel (4) on the cooking area (5b) associated to said switched-on radiant heater (5), said optical receiver (6) being connected to a first control unit (11) of the control device disposed on the support (7b).

2. Control device according to the preceding claim, wherein the support (7b) is built into an extractor hood (7) disposed on the glass-ceramic hob (3).

3. Control device according to any of the preceding claims, wherein the optical receiver (6) is a photodetector sensitive to optical radiation bands that are situated on the visible and/or infrared spectrums.

4. Control device according to any of the preceding claims, wherein the absence detection means (2) comprise an optical receiver (6) associated with each radiant heater (5) and focused in relation to said radiant heater (5).

5. Control device according to any of claims 1 to 3, wherein the absence detection means (2) comprise a single optical receiver (6) focused in relation to the radiant heaters (5) disposed beneath the glass-ceramic hob (3).

6. Control device according to any of the preceding claims, comprising warning means (10) controlled by the first control unit (11), said warning means (10) being light and/or sound devices that warn the user of the absence of the cooking vessel (4) detected by the absence detection means (2).

7. Control device according to any of the preceding claims, comprising safety means (18) for switching off the switched-on radiant heater (5) in the absence of the cooking vessel (4) on the corresponding cooking area (5b), which include a first emitter (13) inserted into the support (7b) and connected to the first control unit (11), and a first receiver (14) disposed on or beneath the glass-ceramic hob (3), which receives a command to switch off the switched-on radiant heater (5) sent from the first emitter (13), said first receiver (14) being connected to a second control unit (12) of the control device disposed on or beneath the glass-ceramic hob (3).

8. Control device according to any of the preceding claims, comprising supervision means (15) for the correct operation of the absence detection means (2) which include a second receiver (16) inserted into the support (7b) and connected to the first control unit (11), and a second emitter (17), disposed on or beneath the glass-ceramic hob (3) and connected to a second control unit (12), which emits a piece of information to the second receiver (16) on the power level of the switched-on radiant heater (5).

9. Control device according to any of claims 1 to 6, comprising safety means (18) that include a first emitter (13) inserted into the support (7b) and connected to the first control unit (11) and a first receiver (14) disposed on or beneath the glass-ceramic hob (3) and connected to a second control unit (12), and supervision means (15) that include a second receiver (16) inserted into the support (7b) and connected to the first control unit (11) and a second emitter (17) disposed over or beneath the glass-ceramic hob (3) and connected to a second control unit (12), the first emitter (13) and the second receiver (16) being built into a first emitter/receiver device, and the second emitter (17) and the first receiver (14) being built into a second emitter/receiver device.

Drawing