EP1806537A2 - Protective screen of glass or glass ceramic for open or closed fireplace - Google Patents

Abstract

The disk has an edge area whose thickness is partially smaller than the thickness in an inner area, where the disk is made of glass or glass ceramic material. The disk is designed in a flat and round-shaped manner, and is attached in a door frame by isolated heat-resistant outer and inner seals (2, 4). The door frame is designed as a metallic door frame, where the width of the door frame is adapted to the width of a facet.

Description

The invention relates to a window glass of glass ceramic for fireplaces or stoves. In principle, the window can also consist of a glass with low thermal expansion, in particular borosilicate glass, if the temperature in the furnace is not too high.

Fireplaces or stoves, which are becoming increasingly popular in the home, typically have a privacy screen coupled to the door to the combustion chamber. The screen is in a known manner predominantly of a colorless glass ceramic. A glass ceramic material suitable for this purpose is commercially available, for example, under the brand ROBAX®. But even a borosilicate glass, which is under the brand BOROFLOAT® commercially, is suitable.

There is the possibility of either the screen in a door frame, e.g. to install in a metallic door frame, or to use the window without frame directly as a door to close the combustion chamber.

• Flach
• Rund
• Winklig
• Mehrfach winklig
• Mehrfach winklig und rund
• Mehrdimensional verformt.

Glass or glass-ceramic privacy glass panels, which are usually made in one piece, may have a different configuration. The following geometrical one-part embodiments of glass or glass ceramic chimney panes are known:

• Flat
• round
• angularly
• Multiple angled
• Multiple angled and round
• Multidimensional deformed.

The starting material in a glass-ceramic privacy screen is in each case a flat glass pane in various thicknesses of 2 to 10 mm, which is deformed by known processes and then ceramized.

Decorations can be applied to the inside and outside of the screen. Furthermore, the screen may be provided with functional and designerischen coatings (one-sided or two-sided). For the mounting of the disc in frameless form and for screw or shaft passages (e.g., door handle, ...), corresponding holes are provided in the glass or glass-ceramic privacy screen.

Lenses, which are installed in a preferably made of steel door frame are prevented by contact with the steel by heat-resistant sealing material. Fig. 4 shows such a construction according to the prior art. The viewing window 1 is held in a door frame, which consists of an outer metal frame 3 and an inner metal frame 5, which are connected to each other via a screw 6. In this case, the viewing window rests against the outer metal frame 3 via an outer seal 2 and an inner seal 4 against the inner metal frame 5.

The different temperature / time loads due to the fire in the combustion chamber affect the different materials such as steel or glass ceramic. Due to the different coefficients of expansion of the different materials it comes thereby twisting and / or to a delay of the door frame, which leads to an increased risk of breakage of the lens.

The invention has for its object to reduce the risk of breakage of the glass-ceramic pane by reducing torsional forces of the door frame on the glass ceramic pane in an existing door frame construction of the glass or glass-ceramic window of a fireplace or stove. It should be possible that the door frame construction can be maintained and possibly only the heat-resistant sealing material must be replaced. In the case of a frameless glass-ceramic viewing window, in particular its weight should be reduced.

The solution to this problem is achieved in a glass of low-expansion glass or glass-ceramic for chimneys or stoves according to the invention in that its thickness in the edge region is at least partially smaller than the thickness of the pane in the interior.

In an existing door frame construction, e.g. 4, it is therefore by the measure according to the invention, as shown in FIG. 3, to a change in geometry of the lens 1 in the contact region of the door frame 3, 5 of the stove. By reducing the thickness of the window in the edge region more space for more sealing material 2, 4 is created in the installation situation of an existing door frame, whereby an increased clearance between the window and the door frame, which defuses the problem of different expansion coefficients.

Appropriately, this measure is achieved by a circumferential facet grinding of the layer disc on the edge of the lens.

Furthermore, by reducing the edge thickness of the lens, the heat conduction in the edge region is reduced transversely to the lens, since the disc is thinner in this area and thus the cross section of the lens is reduced. This effect reduces the temperature of the door frame.

$${\mathrm{t}}_{\mathrm{F}}\mathrm{=}\mathrm{1}\mathrm{mm\; bis\; max}\mathrm{.}\mathrm{Dicke\; des\; Glases}\mathrm{-}\mathrm{1}\mathrm{mm}\mathrm{.}$$

In order to achieve this effect, a certain facet width W _F and residual edge thickness t _{F is} necessary for the facet grinding. These values are in the following areas: $${\mathrm{W}}_{\mathrm{F}}\mathrm{=}\mathrm{2}\mathrm{to}\mathrm{50}\mathrm{mm}$$

$${\mathrm{t}}_{\mathrm{F}}\mathrm{=}\mathrm{1}\mathrm{mm\; to\; max}\mathrm{,}\mathrm{Thickness\; of\; the\; glass}\mathrm{-}\mathrm{1}\mathrm{mm}\mathrm{,}$$

The standard thicknesses for glass-ceramic privacy screens are 3, 4 and 5 mm.

Glass ceramic plates with a circumferential facet cut are known per se ( DE 196 49 767 A1 ). In the known case, however, are glass ceramic cooktops whose aesthetic design is to be improved by the facet cut alone, and do not have the thermal edge loads such as chimney windows, their mitigation is in the case of the invention. It's also through the DE 103 44 439 B3 have become known as such faceted glass ceramic cooking surfaces are prepared appropriately.

By the EP 0 496 243 B1 is an oven door with a protective screen for a microwave oven known, which has a plastic frame with flush inserted transparent polycarbonate disc, which is tapered towards the edge, has. The critical, in particular thermal edge loads as in the case of glass or glass ceramic panes of chimney or stove doors in the case of the invention do not occur in the known oven door.

By reducing the thickness of the window in the edge region, it is also possible with advantage to make the door frame construction much filigree / thin. This can contribute to weight reduction.
The surface of the facet can be used in polished and polished condition.
Glass ceramic plates with a circumferential facet cut are in themselves. The surface of the facet can be used in polished and polished condition.

In principle, a facet can be attached to each of the privacy screens with the geometrical embodiments mentioned at the outset and on every imaginable edge (flat and deformed). The invention is particularly noticeable when the facet is mounted on a flat disc. FIG. 1 shows such an embodiment with a flat glass or glass ceramic pane 1, which, according to FIG. 3, is enclosed in a frame 3 and has a peripheral facet 1 '.

The screen can also be deformed. Various processes can be used for forming, such as bending or gravity sinking. Curved lenses can be easily, ie once 90 ° or more times, for example, be bent by 90 ° twice, ie they have flat surfaces that are angled over a small radius, for example, about 5 mm.
In Fig. 2 is such on both sides by 90 ° angled screen, which is faceted in the angled surfaces 1 a, 1 b, is shown.

Also several bends with different bending angles are adjustable.

Circular shaped lenses (e.g., cylindrical or conical cutouts) may also be provided in different radii with edge faceting, as well as multi-dimensionally deformed discs (e.g., a spherical cap portion) and discs that are circularly and angularly deformed in combination.

The faceting is preferably carried out already in the precursor glass, also called green glass. In the case of deformed window panes, the pane is then reshaped and then ceramized. The ceramization can be carried out by appropriate temperature / time programs until the formation of high quartz mixed crystals or until the formation of Keatitmischkristallen which give the screen a translucent (milky) appearance.

The lens can be decorated or undecorated in the area of the facet. Further facets in the lens are conceivable as a design element at every point.

The multiple refraction of the light by means of the facet edge enhances the brilliance of the flames in the combustion chamber and is reminiscent of the light effects of a diamond in the light.

It is also a frameless design of the lens conceivable. This means that the lens is completely visible. By attaching the facet, the lens gives a fine visual impression through the edge itself. In addition to the designeric effect, the thickness reduction on the edge has the advantage that the side impact risk and thus the risk of breakage is reduced due to reduced attack surface.

Brief Description:

Fig. 1

eine facettierte, in einem Rahmen gehalterte ebene Sichtschutzscheibe,

Fig. 2

eine Sichtschutzscheibe nach Fig. 1, die beidseitig um 90° abgewinkelt ist,

Fig. 3

in einer querschnittlichen Ansicht die abgedichtete Halterung der Sichtschutzscheibe im Rahmen und,

Fig. 4

in einer Darstellung entsprechend Fig. 3 die Halterung einer bekannten, nicht facettierten Sichtschutzscheibe in dem Rahmen.

Show it:

Fig. 1

a faceted, frame-mounted flat screen,

Fig. 2

a screen according to FIG. 1, which is angled on both sides by 90 °,

Fig. 3

in a cross-sectional view, the sealed support of the window in the frame and,

Fig. 4

in a representation corresponding to FIG. 3, the holder of a known, non-faceted screen in the frame.

Claims (10)

Sight glass pane with low thermal expansion or glass ceramic for fireplaces or stoves, characterized in that their thickness in the edge region is at least partially smaller than the pane thickness in the interior. Screen according to claim 1, characterized in that the thickness in the edge region circumferentially over the entire edge is smaller than the pane thickness in the inner region. Screen according to claim 1 or 2, characterized in that it has a facet-like tapering in the thickness edge region. Screening window according to one of claims 1 to 3, characterized in that it is installed in a door frame. Screen according to claim 4, characterized in that the door frame is formed as a metallic door frame. Screen according to one of claims 3 to 5, characterized in that the width of the door frame is adapted to the width of the facet. Screen according to one of claims 1 to 3, characterized in that it is frameless formed as a door. Screen according to one of claims 1 to 7, characterized in that it is flat. Screen according to claim 8, characterized in that it is angled on at least one side. Screening screen according to one of claims 1 to 7, characterized in that it is formed round or deformed multidimensional.

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