EP0339739A2 - Appareil pour la cuisson des aliments - Google Patents

Appareil pour la cuisson des aliments Download PDF

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Publication number
EP0339739A2
EP0339739A2 EP89201055A EP89201055A EP0339739A2 EP 0339739 A2 EP0339739 A2 EP 0339739A2 EP 89201055 A EP89201055 A EP 89201055A EP 89201055 A EP89201055 A EP 89201055A EP 0339739 A2 EP0339739 A2 EP 0339739A2
Authority
EP
European Patent Office
Prior art keywords
approximately
light source
cooking appliance
appliance according
lamp bulb
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP89201055A
Other languages
German (de)
English (en)
Other versions
EP0339739A3 (en
EP0339739B1 (fr
Inventor
Horst Dr. Hörster
Reinhard Dr. Kersten
Erwin Dr. Schnedler
Bruno Dr. Vitt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koninklijke Philips NV
Original Assignee
Philips Patentverwaltung GmbH
Philips Gloeilampenfabrieken NV
Koninklijke Philips Electronics NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=6353090&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0339739(A2) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Philips Patentverwaltung GmbH, Philips Gloeilampenfabrieken NV, Koninklijke Philips Electronics NV filed Critical Philips Patentverwaltung GmbH
Publication of EP0339739A2 publication Critical patent/EP0339739A2/fr
Publication of EP0339739A3 publication Critical patent/EP0339739A3/de
Application granted granted Critical
Publication of EP0339739B1 publication Critical patent/EP0339739B1/fr
Anticipated expiration legal-status Critical
Revoked legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/68—Heating arrangements specially adapted for cooking plates or analogous hot-plates
    • H05B3/74—Non-metallic plates, e.g. vitroceramic, ceramic or glassceramic hobs, also including power or control circuits
    • H05B3/744—Lamps as heat source, i.e. heating elements with protective gas envelope, e.g. halogen lamps

Definitions

  • the invention relates to a cooking appliance with a hotplate, in particular in the form of a glass ceramic plate, and at least one heating device having a light source and an optical filter.
  • the invention has for its object to provide a generic cooking device so that it is easy to manufacture and assemble, and that heat losses during operation are largely avoided.
  • the light source is surrounded by an essentially non-absorbing optical filter which has a high reflectivity range for wavelengths below about 0.73 ⁇ m and above this wavelength high transmittance.
  • the filter can be designed as an interference filter in a known manner be.
  • optical filters can be inserted into the cooking device without additional effort, together with the light source.
  • the optical filters can be applied, for example, on the outside or inside of a light source and thus form a structural unit with the latter. However, they can also be applied, for example, to the outside or inside of a transparent tube surrounding the light source. In both cases, retrofitting of existing cooking appliances with a filter according to the invention is easily possible.
  • the filter surrounds the light source, radiation emanating from it is reflected back into the light source itself.
  • the temperature of a heating coil of the light source can be increased.
  • the energy required for heating the coil can also be reduced while the coil temperature remains essentially the same.
  • An increase in the temperature of the heating coil has the result that the part of the radiation emanating from the coil, which falls in the long-wave range above 2.7 ⁇ m, is reduced. Since, for example, hot plates designed as glass ceramic plates absorb radiation in this area, the amount of heat absorbed and stored by hot plates is also reduced. Cooking processes are therefore better and can be controlled essentially without inertia. Post-cooking after switching off the light source due to heat stored in the hotplate is largely avoided.
  • the filter according to the invention reflects radiation with a wavelength below about 0.7 ⁇ m prevents visible light from being radiated outwards through the hotplate.
  • the filters according to the invention are designed so that their reflectance below approximately 0.7 ⁇ m is approximately 100%, but at least above approximately 95%.
  • a generic filter can be used, for example.
  • hotplates can also be provided which are essentially opaque to radiation in the visible light range. Such an impermeability in the visible radiation range is essentially loss-free, since hot plates are not exposed to radiation in this wave range due to the use of the filter according to the invention.
  • the light source can be operated at an operating temperature of approximately 3,300 K.
  • the proportion of the radiation lying above 2.7 ⁇ m and thus partially absorbed by hot plates is reduced to approximately 11.5%; at an operating temperature of 2,700 K, this proportion is still significantly higher at a comparatively approximately 17.7%.
  • the proportion of radiation that can be absorbed by hot plates is further reduced. Tests carried out at this temperature have determined sufficient values for the lifespan of light sources of 2,000 hours and more.
  • the hotplate is essentially transparent in a wavelength range from approximately 0.7 ⁇ m to approximately 2.7 ⁇ m.
  • the transparency of the hotplate in the wave range in which the optical filter has a very high degree of transmission of over 90% means that the thermal energy can be transferred predominantly in the form of radiant heat to vessels containing cookware. Absorption of the radiation from the light source in the hotplate is largely avoided. As a result, the controllability of the cooking appliance with regard to parboiling or searing processes as well as an abrupt reduction or a complete shutdown of the light source is further improved. At the same time, the possibility of boiling after the light source is switched off is further reduced.
  • the hotplate remains essentially cold due to its permeability to the incident radiation and its low absorption capacity with regard to radiation above 2.7 ⁇ m during operation of the cooking device. Due to the reduced transmittance of hotplates in the wavelength range below about 0.7 ⁇ m, it is largely prevents heating devices from being visible through hot plates.
  • an optical filter with an alternating sequence of a total of 43 high and low refractive index layers, which are applied to the outside or inside of a lamp bulb or a transparent tube essentially enveloping the lamp bulb, with which of the Lamp bulb or tube starting order and layer thickness distribution HO, 13 (L1, H1), 15 (L2, H2), 13 (L3, H3), H4 with each TiO2 layers H0 to H4 with a refractive index of at least about 2.25 and the geometric thickness of about 23.8 nm, 47.7 nm, 61.1 nm, 74.5 nm and 37.3 nm and SiO2 layers L1 to L3 with a refractive index of approximately 1.45 and a geometric thickness of approximately 74.0 nm, 94.8 nm and 115.7 nm.
  • Such a construction of the filter leads to particularly high degrees of reflection for wavelengths below about 0.73 ⁇ m and at the same time to high transmittance in the range above 0.73 ⁇ m. This essentially rules out that visible light is emitted from the light source during operation of the cooking appliance and can penetrate through the hotplate to the outside.
  • the light source has a lamp bulb made of quartz with an inner diameter of approximately 2 to 8 mm, a wall thickness of approximately 1 to 2 mm and a length of approximately 10 to 35 cm.
  • a lamp bulb made of quartz with an inner diameter of approximately 2 to 8 mm, a wall thickness of approximately 1 to 2 mm and a length of approximately 10 to 35 cm.
  • the light source has a single filament, preferably made of tungsten, with a pitch parameter of approximately 1.2 to 1.6 and / or a filament diameter of at least 1 mm.
  • a pitch parameter of approximately 1.2 to 1.6 and / or a filament diameter of at least 1 mm.
  • Such a helix is well suited for refocusing of rays reflected by the filter.
  • the side of the hotplate facing the light source has a light-scattering structure and / or the side of the hotplate facing away from the light source has a structuring which reduces contact with cooking appliances, such as saucepans or the like.
  • a light-scattering structuring on the side of the hotplate facing the light source helps to ensure that rend or outside of the operation of the cooking device can not be seen through the hot plate on the light source or the heating device. This contributes to the improvement of the visual impression of the cooking appliance, because devices lying under the hotplate reduce the aesthetic impression.
  • the structuring on the side facing away from the light source reduces the contact area with cooking vessels. As a result, the heat transfer between the hotplate and the cooking appliance is reduced, so that the influence of any heat portion absorbed by the hotplate on the control behavior of the cooking appliance is reduced. Despite any heat energy stored in the hotplate, the risk of re-cooking after switching off the light source is largely eliminated.
  • a base plate 5 is held opposite the base plate 1 and at a distance from the heating device 3 in a manner not shown.
  • the hotplate 5 serves to hold cooking vessels 7, such as pots or pans.
  • Two light sources 9 are arranged in the heating device 3 at a distance and essentially parallel to one another.
  • both light sources 9 are of identical design as halogen incandescent lamps; however, it is also possible to arrange several light sources of different designs.
  • a reflector 11 is arranged at a distance from the light sources 9.
  • the reflector 11 has two regions 13, 15 which are essentially in the form of parabolic cylinder sections and which run axially parallel to the light sources 9.
  • the reflector 11, which can be designed in accordance with an unpublished patent application by Bauknecht Haustechnik GmbH (application no. 37 23 077.8), achieves an essentially homogeneous radiation intensity on the hotplate 5.
  • Both light sources 9 are surrounded by an essentially non-absorbing optical filter, which is designed as an interference filter and which has a high reflectivity range for wavelengths below about 0.73 ⁇ m. In order to prevent the emission of visible light, the degree of reflection lies for wavelengths below about 0.7 ⁇ m at almost 100%, but at least above 95%.
  • the light sources 9 themselves can be operated at an operating temperature of approximately 3,300 K. At this operating temperature, the service life of the light sources 9 was determined to be approximately 2,000 hours or longer.
  • Lamp bulbs for the light sources 9 can be produced, for example, from quartz with an inner diameter of approximately 2 to 8 mm, a wall thickness of approximately 1 to 2 mm and a length of approximately 10 to 35 cm.
  • the lamp bulbs are filled, for example, with xenon at an operating pressure of approximately 20 to 80 bar, preferably approximately 60 bar, with an inner diameter of 8 mm.
  • Lamp bulbs can furthermore advantageously be filled with krypton, with an operating pressure of approximately 20 to 80 bar, and with methylene bromide CH2Br2 with an operating pressure of approximately 0.1 to 10 mbar, preferably 1 mbar.
  • the filter surrounding the light sources 9 can be applied, for example, to the outer jacket of the lamp bulb; Light sources 9 and filters are then combined in a unit that is easy to manufacture and install. However, filters can also be applied to the inside of lamp bulbs or the transparent tubes surrounding the outside or inside of light sources 9.
  • the properties of an optical filter have a changing sequence of overall 43 high and low refractive index layers, which are applied to the inside of the lamp bulbs, were found to be particularly favorable.
  • Starting from the lamp bulb is the order and layer thickness distribution H0, 13 (L1, H1), 15 (L2, H2), 13 (L3, H3), H4 with each TiO2 layers H0 to H4 with a refractive index of at least about 2.25 and the geometric thickness of about 23.8 nm, 47.7 nm, 61.1 nm, 74.5 nm and 37.3 nm and SiO2 layers L1 to L3 with a refractive index of approximately 1.45 and a geometric thickness of approximately 74.0 nm, 94.8 nm and 115.7 nm.
  • Filters according to the invention can be applied to the lamp bulb or a tube as a carrier substance using known methods, such as physical vapor deposition, chemical vapor deposition, cathode sputtering or immersion.
  • hotplates 5 are advantageously made essentially transparent in a wavelength range from approximately 0.7 ⁇ m to approximately 2.7 ⁇ m.
  • This property is, for example, commercially available from the Nippon Elektric Glass Company under the name “Neoceram-Black”, the company Corning under the name “Corning Material 9632”, the company Schott under the name “Robax” and the Nippon Electric Company under the hot plates made of glass ceramic sold under the name "Neoceram-O".
  • the heating device 3 is not visible through the hotplate 5, in addition to the possibly reduced transmission factor for this wavelength range, it can have a light-scattering structuring on its side facing the heating device 3. As a result, the visual impression of the cooking device cannot pass through below the cook plates 5 lying heaters are reduced.
  • the cooking vessel 7 can be cooled by heat transfer from the cooking vessel 7 to the hotplate 5. This cooling effect results in good controllability of the cooking process.
  • Cooking plates 5 can also have a structure on the sides facing away from heating devices 3 in order to reduce the contact area with cooking vessels 7. Thus, even if heat is absorbed by the hotplate 5, its transition to a cooking vessel 7 is made more difficult. The influence of any radiation absorbed by the hotplate 5 on the controllability of the cooking appliance is thus reduced.
  • known hot plates 5 made of glass ceramic or hardenable, low-iron soft glass it has been found that absorption takes place essentially only in a long-wave range above 2.7 ⁇ m.
  • the radiation component emitted by light sources 9 in this wave range above 2.7 ⁇ m can be reduced to approximately 11.5% by increasing the operating temperature to approximately 3,300 K. In contrast, this share is around 17.7% at a lower operating temperature of approximately 2,700 K. The reduction of this proportion of long-wave radiation thus leads to a reduction in the proportion of radiation that can be absorbed by the hotplate 5.
  • the inventive filter surrounding it contributes to increasing the operating temperature of the light source 9.
  • This essentially absorption-free interference filter in fact essentially reflects the radiation with a wavelength below 0.73 ⁇ m back into the light source 9 with a reflectance of approximately 100%.
  • the filament of a light source 9 for example made of tungsten and not shown in the drawing, can have a pitch parameter of 1.2 to 1.6 and a filament cross section of at least 1 mm.
  • the filter according to the invention acts in the manner of a cold light mirror on the lamp.
  • the filter according to the invention must also reflect the entire visible spectrum with a very high degree of reflection - if possible more than 99% - even when the light is passed through obliquely, since otherwise too much visible light during operation as a result of internal multiple reflections in the light sources 9 by the Hotplate can penetrate to the outside.
  • the filter prevents glare from visible light without loss.
  • the proportion of the radiation energy that can be absorbed by the hotplate 5 is reduced to approximately 10% of the total energy, and on the other hand, the structuring described is sufficient on the side of the hotplate 5 facing away from the heating device 3, the solid-state contact between the hotplate 5 and the cooking vessel 7 and thus also the heat transfer is reduced.
  • the dashed line 20 shows the transmission characteristic of the light source 9 with an optical filter according to the invention. This results in a transmittance of approximately 90% for a wavelength range of approximately 0.73 ⁇ m to 2.7 ⁇ m. For the subsequent wavelength ranges, reflectivities of almost 100% are desirable. From Fig. 2 it can be seen that in the region of the spectral sensitivity of the human eye according to the solid curve 22, radiation from the light source 9 is not emitted. Rather, radiation components in this wavelength range are reflected back into the light source 9 with a degree of reflection of almost 100% without loss and, as explained, contribute to a saving in electrical energy or to an increase in the coil temperature.
  • the specific radiation of a black radiator at a temperature of approximately 3,300 K is shown in FIG. 2 by the curve 24 drawn in with a solid line.
  • Curve 26 shows the transmittance of a visually transparent glass ceramic, as is available, for example, under the name "Robax” from Schott with a thickness of approximately 4 mm.
  • Curve 28 shows the transmittance of a hardenable, low-iron soft glass which, for example, is polished and is available from Vegla under the name "Albarino" with a thickness of approximately 4 mm.
  • Curve 30 shows closing Lich the transmittance of a conventional ceramic glass ceramic plate, such as is available from Schott, for example, with a thickness of approximately 5 mm.
  • FIG. 3 shows the spectral transmittance of a light source 9 which has a quartz lamp bulb and which is coated with the interference filter according to the invention.
  • the curve 32 drawn in throughout shows the spectral transmittance in the case of a perpendicular light path and the curve 34 drawn in broken lines shows the spectral transmittance in the case of an oblique light passage of approximately 45 °.
  • a comparison of the spectral transmittance 32, 34 with the spectral sensitivity of the human eye shown as curve 22 in FIG. 2 shows that the filter according to the invention reflects the entire visible spectrum with a very high degree of reflection even in the case of oblique light passage. It is thus largely prevented that visible light can reach the outside through the hotplate 5 during operation of the cooking appliance.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Electric Stoves And Ranges (AREA)
  • Baking, Grill, Roasting (AREA)
  • Cookers (AREA)
EP89201055A 1988-04-28 1989-04-24 Appareil pour la cuisson des aliments Revoked EP0339739B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3814354A DE3814354A1 (de) 1988-04-28 1988-04-28 Kochgeraet
DE3814354 1988-04-28

Publications (3)

Publication Number Publication Date
EP0339739A2 true EP0339739A2 (fr) 1989-11-02
EP0339739A3 EP0339739A3 (en) 1990-10-24
EP0339739B1 EP0339739B1 (fr) 1993-11-10

Family

ID=6353090

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89201055A Revoked EP0339739B1 (fr) 1988-04-28 1989-04-24 Appareil pour la cuisson des aliments

Country Status (2)

Country Link
EP (1) EP0339739B1 (fr)
DE (2) DE3814354A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1990011671A1 (fr) * 1989-03-21 1990-10-04 Leybold Aktiengesellschaft Dispositif chauffant pour la cuisson d'aliments, notamment plaque de cuisson

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10123601C2 (de) * 2001-05-15 2003-11-20 Schott Glas Kochsystem
DE102004033454A1 (de) * 2004-07-07 2006-01-26 E.G.O. Elektro-Gerätebau GmbH Kochgerät mit Temperaturerfassung und Verfahren zur Temperaturerfassung an einem Kochgerät
DE202011052226U1 (de) 2010-12-08 2012-01-16 Schott Ag Anzeigevorrichtung, insbesondere für Kochflächen
DE202011110029U1 (de) 2011-06-06 2012-10-08 Schott Ag Anzeigevorrichtung

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2137060A (en) * 1983-03-25 1984-09-26 Gen Electric Radiant-Energy Heating and/or Cooking Apparatus
GB2154110A (en) * 1984-01-05 1985-08-29 Ti Domestic Appliances Ltd Improvements in or relating to cooking apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1990011671A1 (fr) * 1989-03-21 1990-10-04 Leybold Aktiengesellschaft Dispositif chauffant pour la cuisson d'aliments, notamment plaque de cuisson

Also Published As

Publication number Publication date
DE58906134D1 (de) 1993-12-16
EP0339739A3 (en) 1990-10-24
EP0339739B1 (fr) 1993-11-10
DE3814354A1 (de) 1989-11-09

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