Patent DE-102009056757-A1 (DE)
Title: Grilling device useful in gas grill and as a cooking plate, comprises a heating element and heat source-protective shield arranged between grill good and the heating element for shielding the heating elements from food residues
Inventor: HENN CHRISTIAN
IPC: C03C3/083
Filed: 2009-12-04
Abstract: The grilling device comprises a heating element and a heat source-protective shield arranged between grill good and the heating element for shielding the heating elements from food residues, which emerge during grilling. The heat source-protective shield has a glass or glass ceramic substrate with a coating at grill good side, which prevents or reduces the diffusion of substance from surfaces that emerges through the burning of food residues on the sources of heat source-protective-shield, in the glass or glass ceramic substrate. The grilling device comprises a heating element and a heat source-protective shield arranged between grill good and the heating element for shielding the heating elements from food residues, which emerge during grilling. The heat source-protective shield has a glass or glass ceramic substrate with a coating at grill good side, which prevents or reduces the diffusion of substance from surfaces that emerges through the burning of food residues on the sources of heat source-protective-shield, in the glass or glass ceramic substrate so that the heat source-protective-shield has a long-term stability by two months of continuous operation at 500[deg] C. No morphological change of substrate or coating occurs when the heat source protective shield is exposed over an hour at 700[deg] C. The coating of the heat source protective-shield prevents or reduces the diffusion of alkali ions such as potassium and sodium ion, and/or phosphorus ions into the glass or glass ceramic substrate. The potassium content is measured as an oxide that is higher than 10 mu m below the surface of the glass or glass ceramic substrate of maximum 1.5 times, and the sodium content is measured as an oxide that is higher than the 2500 mu m below the surface. The glass or glass ceramic is doubled so that it is higher than 10mu m below the surface and is measured after two months in continuous operation at 500[deg] C that is 2500 mu m below the surface. The coating has an oxygen permeation rate of less than 1cm 3>/m 2>on the coating surface, per bar pressure differential, per nm thickness and per a day. The coating is applied by means of a chemical or physical vapor deposition process or liquid phase deposition on the glass or glass ceramic substrate. The coating has layers, which are generated by oscillating the substrate from a target in a device for sputtering. The heat source-protective shield is formed as less than 1 mu g/dm 2>of sodium oxide when the heat source-protective shield is treated in 0.1 mol/l hydrochloric acid at 98[deg] C over an hour in an autoclave and the alkali diffusion is measured by means of an atomic absorption spectroscopy. The glass or glass ceramic substrate has further chromium trioxide impurities of 0.013-0.04 m/m. An independent claim is included for a heat source-protective shield for screening heating elements from food residues.