Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C3/00—Glass compositions
  • C03C3/04—Glass compositions containing silica
  • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
  • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
  • C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C10/00—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition
  • C03C10/0036—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition containing SiO2, Al2O3 and a divalent metal oxide as main constituents
  • C03C10/0045—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition containing SiO2, Al2O3 and a divalent metal oxide as main constituents containing SiO2, Al2O3 and MgO as main constituents
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24C—DOMESTIC STOVES OR RANGES ; DETAILS OF DOMESTIC STOVES OR RANGES, OF GENERAL APPLICATION
  • F24C15/00—Details
  • F24C15/10—Tops, e.g. hot plates; Rings

Definitions

• the present invention relates to a cover plate from easy to clean, easy to process glass ceramic with integrated pot carrier.
• the present invention further relates to a gas hob and a gas hob, which cover plate according to the manner set forth above.
• Gas stoves or electric / gas stoves with cover plates (also called “top sheets") made of glass ceramic have been known for some years and are commercially available. Similar to the conventional stainless steel or steel enamel bowls, these cooking appliances are operated with atmospheric gas burners and are characterized by a comparatively aesthetic appearance and a high degree of ease of cleaning.
• glass ceramics of lithium aluminosilicates such as disclosed in WO 97/00407
• this material is generally characterized by very low thermal expansion coefficients, whereby a high resistance to temperature changes of several hundred Degree is reached.
• pot or pan supports which often have complex, three-dimensional shapes, such as support frame with inwardly projecting fingers, the production of tempered glass or conventional glass-ceramics with low thermal expansion coefficients designed as difficult.
• glass-ceramics are in principle suitable for simple geometries (such as flat plates), but a more complex three-dimensional shaping can only be achieved with great effort.
• glass ceramic material is produced starting from so-called precursor glass.
• precursor glass The specific chemical composition of the precursor glass in this case allows a controlled crystallization, which is initiated and controlled by a suitable thermal treatment (ceramization).
• Another method provides - as is common in the case of conventional glasses - the local heating of the glass ceramic to the deformation before. This process has the disadvantage that its appearance is greatly impaired by disordered crystallization and heterogeneity at the heated site and, in addition, tensions and cracking are favored.
• the object of the present invention is therefore to provide a cover plate with integrated pot support structure made of glass ceramic, which offers both an advantageous appearance, is easy to clean, can be produced in a simple manner in complex design form and an integrated heat indication features.
• This object is achieved by the cover plate according to claims 1 to 5, the gas hob according to claim 6, and the gas hob according to claim 7.
• the glass-ceramic material used for the present invention is characterized by excellent thermal shock resistance, chemical resistance and mechanical resistance.
• glass-ceramic material used for the present invention is the ease of processing. Since this can be vacuum-pressed or hot-formed in a particularly advantageous manner with the aid of molds during the production of the cover plate, numerous three-dimensional design forms are possible even with relatively small radii of curvature.
• Suitable methods for shaping the glass ceramic are not limited to the hot press molding. Rather, the shaping by any method known in the art, such. B. vacuum deformation, sintering or by means of forming rollers.
• Another advantage of the present invention over conventional cast iron or aluminum pan support structures is that no additional protective coating is needed to maintain a pleasing appearance and cleaning comfort.
• the glass-ceramic composition disclosed herein allows integrated heat indication by allowing the glass-ceramic to change color when exposed to heat.
• the consumer receives visually appealing manner immediate visual information about the temperature of the heated components. Best way to carry out the invention
• the present invention relates to a cover plate from easy to clean, easy to process glass ceramic with integrated pan support and heat indication, and a gas hob, which has at least one gas hob according to the above-mentioned type.
• composition of the glass-ceramic material preferably comprises the following constituents in the proportions by weight stated below:
• composition of the glass-ceramic essentially comprises the following constituents in the proportions by weight stated below:
• composition of the glass-ceramic essentially comprises the following constituents in the proportions by weight stated below:
• the glass-ceramic composition contains no components except Si0 2 , Al 2 0 3 , MgO, Ti0 2 , ZnO, Zr0 2 in the abovementioned proportions by weight.
• the determination of the glass-ceramic composition can be carried out, for example, by energy-dispersive X-ray spectroscopy (EDX).
• the glass ceramic according to the invention may contain one or more oxides of monovalent metals (such as Li 2 O, Na 2 O, Cs 2 O or K 2 O), preferably in each case in an amount of 15 wt. % Or less.
• the respective amount of the monovalent metal oxides is 5% by weight or less, further preferably 2% by weight or less.
• the glass-ceramic according to the invention may additionally contain additives which are selected in particular from further oxides of trivalent elements (eg Bi 2 O 3 ), further oxides of tetravalent elements (eg SnO 2 and GeO 2 ), oxides five-valent elements (eg P 2 0 5 or Bi 2 0 5 ), melt accelerators, colorants and fluorescers.
• additives which are selected in particular from further oxides of trivalent elements (eg Bi 2 O 3 ), further oxides of tetravalent elements (eg SnO 2 and GeO 2 ), oxides five-valent elements (eg P 2 0 5 or Bi 2 0 5 ), melt accelerators, colorants and fluorescers.
• colorants and fluorescers are coloring or fluorescent oxides of d and f elements, e.g. the oxides of Sc, Ti, Mn, Fe, Ag, Ce, Pr, Tb, Er and Yb, especially Ti, Mn, Fe, Ag, Ce, Pr, Tb and Er.
• the glass ceramic provided for use according to the invention does not contain any polybrominated biphenyl derivatives, polybrominated diethyl ether derivatives, decabromodiphenyl ethers and compounds of the elements lead, mercury, cadmium and chromium. Therefore, the risk of release of potential toxic and hazardous substances during use of the glass-ceramic is eliminated.
• the crystalline phase of the glass-ceramic is composed of aluminum-magnesium-silicate particles of 5 to 200 nm in size. In a particularly preferred embodiment, the crystalline phase of the glass ceramic is composed of aluminum-magnesium silicate particles of 10 to 100 nm in size.
• the glass-ceramic preferably has a flexural strength of 60 to 120 N / mm 2 , in particular from 60 to 90 N / mm 2 (or MPa). In a particularly preferred Embodiment, the glass-ceramic has a flexural strength of 70 to 80 N / mm 2 (or MPa).
• the determination of the flexural strength can be carried out by numerous methods known in the art. Examples include methods that involve a 3 or 4 point bend, with the test specimen on two blades at a defined distance, and through one via one (3-point bend assembly) or two rolls (4-point bend assembly) of above continuously increasing force is loaded.
• the glass-ceramic has a density of 2.4 to 2.7 g / cm 3 .
• a density of 2.5 to 2.6 g / cm 3 is particularly preferred.
• the glass-ceramic has a Vickers hardness VHN (Vickers Hardness Number) of 4-10 3 to 7-10 3 N / mm 2 (or 4 to 7 GPa). Particularly preferred is a Vickers hardness of 5-10 3 to 6-10 3 N / mm 2 (or 5 to 6 GPa).
• VHN Vickers Hardness Number
• the hardness of Vickers can be determined by known static penetration method for hardness testing, in which an equilateral diamond pyramid is pressed with an opening angle of 136 ° under a specified test force in the workpiece.
• the impression surface is determined from the length of the diagonal of the lasting impression determined by means of a measuring microscope.
• the Vickers hardness VHN is calculated from the ratio of test force to impression surface.
• the glass ceramic is preferably characterized in that it has a linear thermal expansion coefficient a of less than 3-10 "7 K " 1 .
• the glass ceramic up to a temperature of 1200 ° C, no transformation in the glass phase.
• the determination of a and the transformation temperature of the glass-ceramic can be carried out by known analysis methods. Examples are static or called dynamic dilatometric method, in which using a dilatometer, the thermal expansion of the material can be determined as a function of temperature
• the hard glass or the glass ceramic has a refractive index determined by means of refractometry of 1.4 to 1.5, whereby an advantageous appearance is achieved.
• the material has a pleasing appearance and advantageous

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Crystallography & Structural Chemistry (AREA)
• Dispersion Chemistry (AREA)
• Ceramic Engineering (AREA)
• Cookers (AREA)
• Baking, Grill, Roasting (AREA)
• Glass Compositions (AREA)

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Citations (1)

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• 2012
  • 2012-08-14 ES ES201231303A patent/ES2442969A1/es not_active Withdrawn
• 2013
  • 2013-08-05 WO PCT/IB2013/056406 patent/WO2014027274A2/de active Application Filing

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