Glass ceramic panel

Very soon, i.e., just at the very beginning of the development of glass ceramic cooktops, it became evident to Schott that delivery and optimization of only the glass ceramic panel itself - without any assistance to our customers - would not be sufficient to achieve success in the market for this success all compoments/parts of the cooktop - as presented in Fig. 3.2 (and in even more detailed with its surroundings in Fig. 3.3 ) - had to be developed and optimized in perfect harmony with each other. This labourious task was performed in cooperation with our customers, the heating element manufacturers, as well as with cookware and cleaning material manufacturers. 

In Fig. 3.3 a set of these components is shown the heating elements with the temperature limiter, the spring support of the heaters, the steel frame for the Ceran glass ceramic panel, the decoration, the energy regulators, and, last but not least, the cookware and cleaning materials. 

To consolidate and extend the market success it was important that Schott as the producer of the glass ceramic panel did not only pursue the optimization of the glass ceramic panel itself but also of the whole cooking system in order to achieve a cooking system of utmost quality. 

Today, flat glass ceramic panels are available in practically all sizes to be used for ovens and fireplaces. Moreover, curved and formed Robax panels... 

The physical behavior of glass-ceramic panels under impact varies depending on the contact situation. Accordingly, standards distinguish between flat impact (pot impact) and sharp>-edged impact (steel ball impact and Norwegian hammer). 

In order to meet all safety standards, glass ceramic cooktops have to be built into the appliance according to specific instructions. A minimum distance of 10 mm between the heating wires and the glass ceramic panel must be kept to avoid current leakage and breakdown. 

Fig. 5. Relative change in length with temperature of P-quartz glass-ceramics designed for A, precision optics and B, cooktop panels. Curves for C, fused...

Homemade vehicle armor and "bulletproof glass" using clear lex-an plastic sheets,kevlar fabric and fiberglass reinforced ceramic panels that are fired in a standard pottery kiln. 

Laminated composites containing glass or glass-ceramic layers have received relatively limited attention, apart from standard laminate polymer/glass security panels for building, automotive and other glazing applications [49, 50]. 

The Ceran glass-ceramic is colored and is designed for applications in cooker surface panels. 

This technique has been used to produce glass-ceramic components that are particularly useful in equipment manufacturing, micro-mechanics, and in the electrical industry. The material can be used for the following applications gas discharge panels, ink-jet printer plates, fluid devices, and magnetic recording head pads. Examples of these applications are shown in Fig. 4-2. 

Furthermore, this glass-ceramic is easy to shape. The panels made of this material acquire their curved shape directly in the sintering process. As a result, they do not require mechanical post processing as is the case for panels made of natural stone. 

Since the beginning of the development of cooking systems with glass ceramic hobs in the late 1960s, several millions of cooktop panels have been sold worldwide. 

The combination of these advantages in design/appearance and in function was made possible by the special properties of the Ceran cooktop panel, (incorporated in the Ceran-Top-System ) based on the Li20-Al203-Si02 glass ceramic exclusively developed for this application by Schott Glaswerke. 

Low-expansion glass ceramics are widely used as precision parts (see Chap. 4), cooktop panels, stove windows, and cookware. In this section we will focus on the development of transparent glass ceramics used as stove windows (colourless) and cooktop panels (tinted) glass ceramics for cookware are also briefly discussed within this section. 

Depending on the application of low-expansion glass ceramics - we are now focussing on tinted cooktop panels and colourless stove windows - further physical and chemical properties are required from both the production and the user side. To lower production costs, fast and effective processing is required, for example, tank melting, on-line hot forming of panels, as well as fast nucleation rates and crystal growing are absolutely necessary. Moreover, the application of decoration, which, for example, indicates the hot zones of a final cooktop panel, should be performed at the same time as ceramization takes place, without any influence on the production quality. 

Furthermore, the glass ceramic used as a cooktop panel has to meet transmission specifications it has to be nearly opaque in the visible spectrum to avoid a direct view to the electric heating elements of the cooktop assembly. On the other hand, the glass ceramic should have a high transmission for infrared radiation to support the overall heating performance. 

As mentioned before, glass ceramics used as cooktop panels have, furthermore, to meet specific transmission specifications in the visible (nearly opaque) and in the near IR (transparent) spectral regions. Different well-... 

The physical and chemical properties of a typical glass ceramic produced in that way and used as a cooktop panel are summarized in Table 3.3 [3.22]. 

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