EP3115698A1 - Hotplate - Google Patents

Abstract

A cooktop (11) has a cooktop panel (13) and a plurality of heaters disposed thereunder, wherein the cooktop panel (13) is adapted to transmit light in the wavelength range visible to the human eye. The heating device has an electrical resistance heater (21), which is arranged on a carrier (17) with thermal insulation. IR-stimulatable material (23, 23a, 23b, 23c, 23d, 23e), in particular material with quantum dots, is provided as a light indicator (24) or illumination on the resistance heater (21) and / or on the thermal insulation and / or on the cooktop panel ( 13) arranged. The IR-stimulatable material (23,23a, 23b, 23c, 23d, 23e) is designed such that it can be excited by light in the IR wavelength range for emitting light for the illuminated display (24).

Description

The invention relates to a hob with a hob plate and at least one heating device arranged thereunder.

For example, from the DE 102011085112 A1 or the DE 102012204546 A1 are displays or lights on hobs known that do not work with just a light source such as a visible LED. Here, materials with exceptional properties are used.

TASK and SOLUTION

The invention has for its object to provide an aforementioned cooktop, can be solved with the problems of the prior art and it is particularly possible to provide an advantageous light indicator on a hob.

This object is achieved by a hob with the features of claim 1. Advantageous and preferred embodiments of the invention are the subject of further claims and are explained in more detail below. The wording of the claims is made the subject of the present application by express reference.

It is envisaged that the hob has a hob plate and at least one heating device arranged thereunder. The hob plate can advantageously consist of hard glass or glass ceramic, as is known per se. It can be colored largely transparent or reddish-brown. The cooktop panel is advantageously designed so that it transmits light in a visible to the human eye wavelength range, even if this is only a small permeability. This wavelength range is from about 380nm to 780nm. The permeability does not necessarily apply to the entire visible to the human eye wavelength range, but may also apply to narrow areas or substantially individual colors. In the IR wavelength range, the cooktop panel can be translucent or have a transmission of more than 50%, advantageously more than 80% or even 90%. This is particularly advantageous when using radiant heaters or generally electrical resistance heaters, which have very high temperatures and thus a very high proportion of IR radiation.

The heater operates electrically and preferably has an electrical resistance heater, which is arranged on a support with thermal insulation. On the one hand, this can be a so-called band-shaped resistance heater as radiant heater, as it is known, for example, from the EP 585831 A1 is known. Here, the electrical resistance heater with its band is exposed to the atmosphere, wherein it is partially disposed on a support with a thermal insulation. The thermal insulation may advantageously be formed flat or plate-like or plate-like, wherein the resistance heater or the resistance heating rests on it under possible Teileinbettung.

Alternatively, the heater may have an electrical resistance heater in the form of a so-called tubular heater, as he, for example, from the DE 102009048495 A1 is known. In this case, the actual resistance heating element is surrounded by insulating material in a metal tube, which can ultimately be heated by the resistance heating element or even made to glow and then also works as a radiant heater. In a further alternative, an electrical resistance heater may be a so-called halogen lamp, also known as a light radiator, as can also be used for hobs. Also, the alternative resistance heaters are arranged on carriers with thermal insulation to increase the heat radiation upwards to a mounted on the cooktop plate above cooking vessel or to improve energy efficiency. Furthermore, a heating of the hob downwards in a built-in furniture or the like. not too big.

An IR-stimulable material which forms a light display or a lighting, is designed so that it can be excited by light in the IR wavelength range and then emits light. So it can serve as the aforementioned indicator or lighting. This effect is a fluorescence or these materials are also called anti-Stokes materials. Light in the IR wavelength range is indeed present by the aforementioned resistance heater during heating operation in any case and usually a short time afterwards, while just the resistance heater, for example, after switching off is still hot enough or as long as it is not too cold , By using the IR-stimulatable material, which may be in particular material with quantum dots, a light display or lighting can be generated with other colors than with red to orange or orange-yellow, as it emit conventional glowing resistance heaters. Such IR-stimulable materials are also from the US 4806772 A The content of these materials is made explicit reference to the content of the present application.

The IR-stimulatable material is arranged on the resistance heater and / or on the thermal insulation and / or on the hob plate and / or on an additional carrier. Advantageously, the IR-stimulable material is in the immediate area of high irradiation with heat radiation by the heater or the resistance heater. The arrangement of the IR-stimulable material on an additional carrier or the like, which may be arranged on the heater or especially on the thermal insulation, although the cost of an additional part, which eliminates the use of already existing parts of the hob or the heater but is possible.

This IR-stimulable material should be selected accordingly temperature stable, so that a long-term temperature stability is given for temperatures above 1000 ° C. These should be even higher, especially with exposed electrical resistance heaters, which glow visibly bright in heating mode, for example up to 1300 ° C. The aforementioned tubular heaters are usually not hotter than 1000 ° C, even if they are already beginning to glow.

An advantage of the high temperature stability or temperature stability of the materials, in addition to the use at high heat conductor temperatures, is also that this temperature resistance can be achieved at high temperatures, e.g. Enamelling, casting, sintering, baking or the like only possible.

The IR-stimulable material may generally be rare-earth doped. Advantageously, it may contain erbium or be doped with erbium. This can be particularly advantageous Er ³⁺ . The IR-stimulable material is preferably material with so-called quantum dots or quantum wires. Such materials, also called anti-Stokes materials, just radiate visible light when excited by IR radiation or heat. Due to the size of the constituents of the material, in particular the quantum dots, the wavelength of the emitted light can be influenced within certain limits. Thus, for example, by quantum dots from the company CAN from Hamburg under the product name CANdots Series X Green, a peak of the light emitted by the material with the quantum dots in the wavelength range between 510nm and 560nm can be achieved. In another wavelength range between 640nm and 690nm, another emission peak may be present.

The IR-stimulatable material can be provided as a light indicator recognizable from above through the hob plate, advantageously in the area or heating area of the at least one heating device. In one embodiment of the invention, it is possible that the IR-stimulatable material at least partially disposed directly above the heater on the hob plate is, preferably at the bottom of the hob plate. Although an attachment to the top of the hob plate would also be possible, but here is the mechanical stress in daily use when cooking in the long term too large for the resistance of these IR-stimulable materials or quantum dots. Therefore, it is considered advantageous if the IR-stimulatable material is arranged on the underside of the hob plate or is applied to the underside of the hob plate. It is advantageous applied as a coating on the hob plate. At the same time, however, it should still be largely or even completely permeable to the IR heat radiation of the resistance heating element to the outside.

In an alternative embodiment of the invention, the IR-stimulatable material may be an integral part of the cooktop panel or mixed with the material of the cooktop panel. In this case, the IR-stimulable material does not form a coating, but is incorporated in the material of the hob plate. Furthermore, it is possible to mix the IR-stimulatable material into the material of the hob plate in such a way that certain shapes or symbols are formed, in particular matched to the later arrangement of the heater on the hob. Thus, complex coating processes can be omitted.

In a further alternative embodiment of the invention, the IR-stimulatable material may be provided on the heating device, advantageously directly thereto. It may, for example, be provided directly to the aforementioned thermal insulation or to the aforementioned carrier, since thereby the properties with respect to the heat generation and heat radiation at the resistance heater are lower. The temperature at an exposed resistance heater is very high even with the aforementioned 1000 ° C to 1100 ° C and thus thermally very demanding both for the IR-stimulable material and for the operation of the heater. On the thermal insulation, the IR-stimulatable material may be applied on the one hand as a coating, for example on the surfaces or regions of the thermal insulation which are easily recognizable from the outside or from above. Such thermal insulation may be formed according to the example EP 750444A as commonly used for radiant heaters. For flat and not too fine or detailed coatings, this surface is suitable for this thermal insulation.

On the other hand, the IR-stimulable material can also be mixed into the material of the thermal insulation, for example the quantum dots directly, and thus an integral production can take place, for example as pressing. Then, however, the need for such IR stimulatory is Material very high for the relatively low proportion, which is later provided on surfaces visible from above.

Preferably, certain surfaces of the thermal insulation which are directed upwards or are particularly easily recognizable from above can be provided with the IR-stimulable material. This may be, for example, an edge region of the carrier or thermal insulation surrounding the resistance heater, alternatively a free center region.

In yet another alternative embodiment of the invention, the IR-stimulatable material can also be provided directly on the heater, directly to the resistance heater. This is particularly useful when the resistance heater is an aforementioned tubular heater whose surface or outer shell, usually a metal tube, reaches temperatures of less than 1000 ° C, that is less hot than an aforementioned exposed resistance heater of a radiant heater.

In general, it is considered advantageous if such areas are provided or coated with IR-stimulatable material, which are clearly visible from above. Thus, for example, in the case of a resistance heater in the manner of a tubular heater, no full coating of the tubular heater needs to be provided, a coating on the top with IR-stimulable material suffices.

Alternatively, the IR-stimulable material may be attached to a support attached to the heater according to the aforementioned additional support, which may advantageously be made of metal, glass or glass-ceramic. The carrier may be disposed between the heater and the cooktop panel. In a further embodiment of the invention, the carrier between the heater and the hob plate may be formed as a light guide or light channel.

In an advantageous embodiment of the invention, a material with two different quantum dots or two different types of quantum dots can be provided, which are designed for the representation of two different colors in operation as a light indicator. The two different colors are then created by different exposure to different temperatures. Thus, not only in general a triggered by IR or heat radiation light indicator or lighting on a hob is possible, but also a different depending on the temperature color indicator. This is for example for residual heat heating displays on a hob advantageous.

In an embodiment of the invention, thermochromic material may be provided over the IR-stimulable material in a layered construction. Here, a layer structure can be selected, which should be provided on the hob plate or on its underside or under the hob plate. It is considered advantageous if the extent of the thermochromic material is about the same size as that of the IR-stimulable material below, at least it should have the same areal coverage. Alternatively, certain areas may be covered and certain areas may be left blank so that when a certain temperature for that thermochromic material is exceeded, an underlying IR-stimulable material will be visible only when the thermochromic material has its color change.

For producing a coating with the IR-stimulable material or with quantum dots, a starting material, often a powder, can be processed in a dispersion. This in turn may be admixed with a dispersion material such as a paint or other carrier material. This can then be mixed or applied again in the desired manner.

These and other features will become apparent from the claims and from the description and drawings, wherein the individual features in each case alone or more in the form of sub-combinations in an embodiment of the invention and in other fields be realized and advantageous and protectable Represent embodiments for which protection is claimed here. The subdivision of the application into individual sections and intermediate headings does not limit the statements made thereunder in their generality.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

einen Schnitt durch ein erfindungsgemäßes Kochfeld mit Strahlungsheizkörper, an dem auf unterschiedliche Arten IR-stimulierbare bzw. Quantendot-Beschichtungen aufgebracht sind,

Fig. 2

einen Schnitt durch einen Rohrheizkörper als alternative Heizeinrichtung,

Fig. 3

eine Schemadarstellung einer mehrschichtigen Beschichtung mit einer thermochromen Beschichtung über einer Quantendot-Beschichtung,

Fig. 4

eine Draufsicht auf das Kochfeld entsprechend Fig. 1 mit strichliertem Strahlungsheizkörper und punktiertem Leuchtring einer leuchtenden Quantendot-Beschichtung und

Fig. 5

ein Strahlungsspektrum von Quantendots mit zwei hauptsächlichen Wellenlängenbe-reichen der Abstrahlung.

Embodiments of the invention are shown schematically in the drawings and are explained in more detail below. In the drawings show:

Fig. 1

a section through a cooking hob according to the invention with radiant heater, on which IR-stimulable or quantum-red coatings are applied in different ways,

Fig. 2

a section through a tubular heater as an alternative heating device,

Fig. 3

a schematic representation of a multilayer coating with a thermochromic coating over a quantum dot coating,

Fig. 4

a plan view of the hob accordingly Fig. 1 with dashed radiant heater and dotted luminous ring of a luminous quantum dot coating and

Fig. 5

a radiation spectrum of quantum dots with two major wavelengths of radiation.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the Fig. 1 On average, an inventive hob 11 is shown, which is formed largely in the usual way. It has a hob plate 13, advantageously made of glass ceramic such as KeraVision from EuroKera or Hightrans from SCHOTT. On a bottom 14 of the hob plate 13, a radiant heater 16 is pressed, as is usual. The hob can have several such radiant heaters.

The radiant heater 16 is largely constructed according to the aforementioned prior art and has a plate-like or plate-like carrier 17 made of a thermal insulation material. It has externally attached or molded on a circumferential support edge 18. Under certain circumstances, the carrier 17 may be held from the thermal insulation material in a kind of sheet metal plate, which plays no role for the invention. Between the support edge 18 and support 17, an oblique edge throat 19 may be provided. On the support 17, a resistance heater 21 is arranged standing. It has the shape of an upright ribbon and runs spirally or meandering on the carrier 17th

A coating with IR-stimulable material, here with material with quantum dots, can be arranged in different ways on the radiant heater 16 or the carrier 17 or the carrier edge 18. A first possibility is a quantum dot coating 23a on the upper side of the carrier edge 18. It can be completely circumferential or individual dots, areas, symbols or the like. form. Since this quantum dot coating 23a is pressed directly onto the underside 14 of the hob plate 13, its visibility from above is very good. At the same time, however, it may only be achieved to a limited extent by the IR radiation of the resistance heater 21 of the radiant heater 16. Such an IR-stimulable material can either initially have quantum dots with erbium doping or according to the aforementioned US 4806772 A be educated.

Another IR-stimulable quantum dot coating 23b is provided on the inwardly facing side of the carrier rim 18. It may also be formed completely or largely circumferentially as a kind of ring, alternatively as individual dots or the like, as has been previously carried out for the quantum dot coating 23a. Although the visibility of the quantum dot coating 23b on the sides of the carrier rim 18 from above is less good, it can be very well illuminated by the IR radiation of the resistance heater 21.

Another IR-stimulable quantum dot coating 23c is applied to the edge throat 19, which is specially provided for this purpose. This quantum dot coating 23 c can be seen quite well from above as well as being readily illuminable by the IR radiation of the resistance heater 21. Again, a coating can take place in different shapes, as a long or even continuous strip, alternatively as individual dots, symbols or the like.

According to a further possibility, an IR-stimulable quantum dot coating 23d can be applied to the carrier 17 or its upper side, for example centrally, but also at the edge region. Although not much space may be available here, both visibility and suitability are very good.

Yet another possibility of an IR-stimulable coating is a quantum dot coating 23e on the underside 14 of the hob plate 13. It has the advantage that it is both very visible from above and very well from the IR radiation of the resistance heater 21st can be illuminated. However, it has the disadvantage that it is not attached to the radiant heater 16 itself, but just on the hob plate 13. So it must be applied in completely different steps.

As an alternative to a coating, bonding with a film, a glass plate or any other suitable carrier is also possible in each case, on which a quantum dot coating 23 is applied.

In Fig. 2 an alternative heating device is shown, as it could be used for an oven or for a hob. A tubular heater 116 has a metallic tube in which a heating wire 121 extends. In addition, the tube is filled with powdery or granular insulating material. Such a tubular heater 116 may be formed in the manner mentioned above and form the aforementioned resistance heater.

On top of the tubular heater 116, an IR-stimulable quantum dot coating 123 is applied. It can essentially cover the upper half, for example, but only an upper third or upper quarter, which just as well as possible to see from above or can be seen. Although the resistance heaters 21 of the radiant heater 16 of the Fig. 1 be provided directly with a quantum dot coating. Their high temperatures in the heating mode of about 1100 ° C, however, make a coating difficult. In addition, the efficiency could be adversely affected.

In the Fig. 3 schematically a layer structure is shown with an IR-stimulable quantum dot coating 23, on which a thermochromic coating 25 is arranged. As previously described, the thermochromic coating 25 may change color or even become transparent at a certain temperature. Thus, at this temperature, the visibility of an underlying quantum dot coating 23 is given or no longer exists. Furthermore, the color may change due to the thermochromic coating 25. Based on Fig. 3 it is also easy to imagine how a layer structure with even more layers could be done, for example, several IR-stimulable quantum dot coatings on top of each other.

In the Fig. 4 is a plan view of the hob 11 from the Fig. 1 with lights of an IR-stimulable quantum dot coating 23c as a light indicator 24 in the form of a circumferential, dotted ring shown luminous. This indicator 24 is visible through the hob plate 13 through and can, for example, a power indicator or hot display for the radiant heater 16 and its heating operation represent.

In the Fig. 5 is shown a radiation spectrum of an IR-stimulable quantum dot coating or material with quantum dots. These are quantum dots from CAN in Hamburg called CANdots Series X Green. These quantum dots consist of so-called "core" particles of NaYF ₄ : Yb, Er. This is the lower curve with the very low rashes at around 540nm and 650nm. They can be excited by IR radiation to illuminate.

Furthermore, the upper curve for quantum dots is represented by so-called "core / shell" particles. These consist of NaYF ₄ : Yb, Er / NaYF ₄ . The maxima of this emission or radiation are much higher, but are in principle at about the same wavelength. The resulting color is then just green. Irradiation of the respective IR-stimulable materials with quantum dots takes place by means of near IR light with a wavelength of 980 nm, for example, as it is included in the spectrum of the radiant heater 16 and the resistance heater 21 in the heating mode.

Claims (12)

Hob with a cooktop panel and at least one heater arranged below, characterized by : the cooktop has a cooktop plate which is designed to transmit light in the wavelength range visible to the human eye, the heating device has an electrical resistance heater and a support with thermal insulation, wherein the electrical resistance heater is arranged on the support with thermal insulation, IR-stimulable material as a light display or illumination, which is designed such that it can be excited by light in the IR wavelength range for emitting light, - The IR-stimulatable material is disposed on the resistance heater and / or on the thermal insulation and / or on the cooktop plate and / or on an additional carrier. Hob according to claim 1, characterized in that the IR-stimulatable material has a long-term temperature stability at temperatures of about 1000 ° C to 1300 ° C. Cooking field according to claim 1 or 2, characterized in that the IR-stimulatable material contains Erbium or is doped with erbium, preferably Er ³⁺ . Cooking field according to one of the preceding claims, characterized in that the IR-stimulatable material are quantum dots or that it has quantum dots. Hob according to one of the preceding claims, characterized in that the IR-stimulatable material is provided as a light indicator in the region or heating region of the at least one heating device. Hob according to one of the preceding claims, characterized in that the IR-stimulatable material is at least partially disposed directly above the heater on the hob plate, preferably on the underside of the hob plate, wherein in particular the IR-stimulable material is applied as a coating insoluble on the hob plate , Hob according to one of the preceding claims, characterized in that the IR-stimulatable material is an integral part of the hob plate or the material of the hob plate is mixed. Cooking field according to one of claims 1 to 5, characterized in that the IR-stimulatable material is provided directly on the heating device, preferably on the thermal insulation, wherein in particular the IR-stimulatable material is applied as a coating to the thermal insulation. Cooking field according to one of claims 1 to 5, characterized in that the IR-stimulatable material is provided directly on the heating device, preferably directly to the resistance heater, wherein in particular the IR-stimulatable material is applied as a coating on the resistance heater. Hob according to one of claims 1 to 6, characterized in that the IR-stimulable material is attached to a mounted on the heater support metal, glass or glass ceramic between the heater and the hob plate, preferably the carrier between the heater and the hob plate is designed as a light guide. Hob according to one of the preceding claims, characterized in that IR-stimulable material for the representation of two different colors is formed in operation as a light display, wherein the two different colors are formed by different exposure to different temperatures. Cooking field according to one of the preceding claims, characterized in that thermochromic material is provided in a layer structure over the IR-stimulable material, in particular on the hob plate or under the hob plate, preferably with the same areal coverage.

Images