EP1094277B1 - Oven with glass plate for oven door - Google Patents

Abstract

The door glass is pre-curved, and size and direction of the shaping are adapted to the temperature-dependent expansion of the glass pane (10), so that the curvature is not transferred to the other side of the glass door pane. The convex side of the glass is on the inside (4) of the oven, an the concave side is on the outside. The glass is a single or laminated pane, esp. toughened glass. The glass layer facing the oven interior has a higher heat expansion coefficient than the outer layer.

Description

The invention relates to an oven with an oven door glass pane according to the preamble of claim 1.

The invention relates to the problem of thermal heat distortion of glass panes of oven doors. For oven doors with multiple glass panes, this affects Invention in particular the oven door inner pane. Glass panes bulge depending on the temperature, very strong in some cases. Depending on Glass tempering and depending on the uneven thermal load on the glass pane the glass may become unstable or in a stable state when hot are located. An unstable condition can lead to excessive noise to lead. By "unstable" condition is meant a condition in which Glass bulges can shift from one side of the glass to the other and vice versa, which is often associated with loud noise is.

The temperature of the oven acts on one side on the glass pane of the oven door Oven interior, which is between room temperature of about 10 ° C to 30 ° C can fluctuate to over 300 ° C, and on the other hand the temperature of the Oven outside in the kitchen, in which the oven is located, and which relative is constant between about 10 ° C and 30 ° C. The heat is distributed in the Glass pane mostly not evenly and leads especially with such uneven Thermal stresses to high stresses and deformations in the Glass pane. Because the glasses are designed as flat panes in the prior art there are different deformations and different Bulges. One or more different can be inside the glass pane Deformations and different curvatures arise. A curvature can be in different areas have different radii of curvature.

Known measures to reduce adverse heat effects on the Glass pane of the oven door consist of the glass pane with reflective To provide coatings and / or heat distribution through air ducts in the To improve the area of the glass pane.

The object of the invention is to solve breaks and noises Oven-glass pane, which are caused by strong temperature changes simple and reliable way and in a predictable manner for all types of ovens Way to avoid safely.

This object is achieved according to the invention in that the size and direction of the crowning the temperature-dependent expansion properties of the glass pane are adjusted in this way are that the crowning over the entire oven heating temperature range cannot turn in the opposite direction to the crown.

Advantages of the invention: the oven door glass pane, in particular the inner pane an oven door, is prebombed so that the crowning over the entire thermal oven heating process is controllable. So that are also thermal Dimensional changes of the glass pane and the metal structure of the Oven door can be predetermined. Furthermore, the risk of noise is minimized because the Bombing is chosen such that the one directed towards one side of the glass pane Bombing not on the other side of the glass pane during the oven heating process can handle. Furthermore, the crowning can also cause relative movements between the glass pane and the frame structure receiving it the oven door can be reduced.

The invention is based on the idea that the heat distribution in the Glass pane can only be improved insignificantly that the temperature-dependent Linear expansion of the glass pane must be accepted by targeted Pre-crowning in the hot surfaces of the glass pane is the direction for the temperature-dependent Linear expansion can be predetermined. The crowning of the Glass pane can be used in process engineering in the manufacture of the glass pane control and achieve through targeted cooling air distribution during the cooling process, with this targeted cooling air distribution a corresponding glass tempering results, through which the glass pane in the cooled state has predetermined curvature (crowning).

In the context of the invention, crowning means a curvature of the glass pane, which the pane of glass has when it is the same on both sides of the pane Is exposed to ambient temperature. Thus, the glass pane according to the Prebombed invention.

Fig. 1

schematisch einen vertikalen Querschnitt durch einen Backofen mit einer konvex in den Backofeninnenraum gewölbten Türglasscheibe,

Fig. 2

schematisch einen Vertikalschnitt eines Backofens mit einer konvex aus dem Backofeninnenraum herausgewölbten Türglasscheibe, d. h. sie ist auf ihrer dem Backofeninnenraum zugewandten Seite konkav gewölbt,

Fig. 3

eine Seitenansicht der Türglasscheibe von Fig. 1 in Form einer Einfachscheibe (einschichtige Glasscheibe),

Fig. 4

eine Seitenansicht der Türglasscheibe von Fig. 2 in Form einer Einfachscheibe (einschichtige Glasscheibe),

Fig. 5

eine Seitenansicht der Türglasscheibe von Fig. 1 in Form einer Verbundglasscheibe (2-oder mehrschichtige Glasscheibe);

Fig. 6

eine Seitenansicht der Türglasscheibe von Fig. 2 in Form einer Verbundglasscheibe (2-oder mehrschichtige Glasscheibe).

The invention is described below with reference to the drawings using preferred embodiments as examples. Show in the drawings

Fig. 1

schematically a vertical cross section through an oven with a convexly curved door glass pane in the interior of the oven,

Fig. 2

schematically shows a vertical section of an oven with a door glass pane convexly curved out of the interior of the oven, ie it is concavely curved on its side facing the interior of the oven,

Fig. 3

1 in the form of a single pane (single-layer glass pane),

Fig. 4

2 in the form of a single pane (single-layer glass pane),

Fig. 5

a side view of the door glass pane of Figure 1 in the form of a laminated glass pane (2 or multilayer glass pane);

Fig. 6

a side view of the door glass pane of FIG. 2 in the form of a laminated glass pane (2 or multilayer glass pane).

In Figures 3-6, the door glass panes are disproportionate and one larger crowning (curvature) than shown in reality to the To make invention clearer. In all embodiments, the glass is preferred a so-called tempered glass.

The term oven used here refers not only to ovens for baking, but any kind of heatable equipment room with an equipment room door that with a glass pane as a viewing window for observing the cooking process from Food is provided in the equipment room, e.g. also grills or combined baking and grilling devices. The equipment room is therefore described below referred to as oven interior 4.

The ovens 2 of FIGS. 1 and 2 have an electrically or gas heated Interior 4 (baking room), which on the front through an oven door 6 is lockable. The oven door 6 is about a horizontal hinge 8 and too pivotable.

The oven door 6 of FIG. 1 contains a viewing window 14 with a glass pane 10, which is arched into the interior 4. The glass pane 10 thus has a convexity extending into the interior 4, in the following called "convex crowning".

The oven door 6 of FIG. 2 has a viewing window 14 with one from the interior 4 convexly curved glass pane 12. This glass pane 12 thus has a convex curvature from inside 4, being concave on its side facing the interior 4, in the following called "concave crowning".

Various embodiments of the glass pane 10 of FIG Fig. 1 and the glass sheet 12 of Fig. 2 compared with each other.

3 shows a side view of a glass pane 10 from FIG. 1 in the form of a single glass pane, that is, a single-layer pane of glass that prebombs is so that they are at the same temperature on both sides of the glass in the interior 4 inside, that is convex, is arched. With increasing temperature in the interior 4 and approximately constant temperature on the outside of the oven the curvature becomes larger, ie the radius of curvature becomes smaller. This has the advantage that the crowning (curvature) is not used in practice occurring temperature difference between interior 4 and oven exterior can turn to the other side. That is the crowning cannot become concave.

Fig. 4 shows the glass sheet 12 of Fig. 2 in the form of a "single glass sheet", i. H. a single-layer glass pane, which is prebombed, so that it is in the Interior has 4 concave curvature or crowning, if on both sides of the glass the temperature is approximately the same. This has increased with increasing Temperature in the interior 4 and approximately constant temperature on the Oven outside the disadvantage that the crowning on the other side with can strike through a loud bang or that to avoid such Penetration or tipping over the crown must be very large.

FIG. 5 shows the glass pane 10 from FIG. 1 in the form of at least two Glass layers 10-1 and 10-2 existing laminated glass pane, which is prebombed is so that it is convex into the interior 4 when on both sides of the glass pane have approximately the same temperature.

First embodiment of FIG. 5, in which all glass layers 10-1 and 10-2 have the same coefficient of thermal expansion, i. H. is temperature dependent expand or contract in the same way. The glass pane 10 bulges into the interior 4, the higher the heating temperature inside, while the outside oven temperature remains approximately constant. This has the advantage that the crowning does not change over to the other side can, i.e. not from the interior to the oven exterior.

Second embodiment of Fig. 5, in which the glass layer 10-1, which facing the oven interior 4, a larger coefficient of thermal expansion has than that on the outside of the oven facing away arranged glass layer 10-2 so that the inner glass layer 10-1 per degree Temperature change expands or contracts much more than that outer glass layer 10-2. Again, this has the advantage that the crowning is not can turn to the other side. This also creates the risk of glass breakage reduced because the one with the greater coefficient of thermal expansion inner glass layer 10-1 on the convex and therefore larger in area Side of the laminated glass pane 10 is arranged.

Third embodiment of Fig. 5, in which the on the outside of the oven arranged glass layer 10-2 a larger coefficient of thermal expansion has as the glass layer 10-1 arranged on the inside of the oven. Here there is a risk that the crowning of the Turns the inside of the oven to the outside of the oven and the layers of glass break provided the different thermal expansion coefficient for this is large enough with reference to the fact that the temperature in the interior 4 can rise from about 20 ° C to 300 ° C and higher while on the The outside of the oven remains at around 20 ° C.

FIG. 6 shows the glass pane 12 from FIG. 2 in the form of at least two Glass layers 12-1 and 12-2 existing laminated glass, which is prebombed is so that it is convex out of the interior 4 when the temperature on both sides of the glass is approximately the same. This means, that the laminated glass pane 12 facing the inner space 4 Side is concave.

First embodiment of FIG. 6, in which both glass layers 12-1 and 12-2 have the same coefficient of thermal expansion. In this case itself when the interior 4 heats up from room temperature of about 20 ° C to baking temperature or grill temperature of up to or above 300 ° C, while on the outside of the oven the room temperature is around 20 ° C remains, the inner glass layer 12-1 expand much more than the outer Glass layer 12-2. There is a risk that the crowning from the outside turns over on the inside, which can produce a strong bang, and the risk that the laminated glass pane breaks. Due to the temperature strong expansions and contractions also create strong relative movements between the laminated glass pane and the parts holding it the oven door 6.

Second embodiment of FIG. 6, in which the interior 4 facing inner glass layer 12-1 has a larger coefficient of thermal expansion has as the glass layer 12-2 arranged on the outside of the oven. This will cause the curvature or crowning to change from the outside of the oven in the direction of the interior 4 can not be avoided a temperature increase in the interior 4 from room temperature to baking temperature or grill temperature while the temperature is on the outside of the oven remains essentially constant.

Third embodiment of Fig. 6, in which the on the outside of the oven lying glass layer 12-2 has a larger coefficient of thermal expansion than the inner glass layer 12-1 facing the interior 4. Here would be the Bulge or crown remain on the same side when on both A uniform temperature change would take place on the glass pane sides. However, since in the interior 4 the temperature at baking temperature or grill temperature can rise to over 300 ° C, while on the outside in remains essentially at 20 ° C, such a change in the crowning takes place from one side to the other side only if the different Thermal expansion coefficients come into effect more than that Temperature differences between the inside and outside.

The glass pane 10 or 12 can not only with a crown, but also be provided with several crowns, i.e. with one or more arches each in the same or in different directions. This one or several curvatures or curvatures can have a uniform radius of curvature or a radius of curvature that changes across the crown to have. In areas with less temperature change during operation a smaller prebombing is usually more appropriate than in other areas where there are major temperature changes occur when baking or grilling.

Claims (6)

1. Baking oven with baking oven door glass pane, wherein this is pre-bowed, characterised in that the size and direction of the bowing is so matched to the temperature-dependent expansion characteristics of the glass pane (10; 12) that the bowing over the entire baking oven heating temperature range cannot change over to the opposite direction of the bowing.
2. Baking oven with baking oven glass pane according to claim 1, characterised in that the convex side of the bowing is on the baking oven inner side (4) and the concave side of the bowing is on the baking oven outer side.
3. Baking oven with baking oven door glass pane according to claim 1 or 2, characterised in that it is a single layer pane.
4. Baking oven with baking oven door glass pane according to claim 1 or 2, characterised in that it is a laminated glass pane.
5. Baking oven with baking oven door glass pane according to claim 4, characterised in that the pane lamination (10-1; 12-1) disposed closer to the baking oven interior space (4) has a greater coefficient of thermal expansion than the pane lamination (10-2; 12-2) disposed further away.
6. Baking oven with baking oven door glass pane according to one of the preceding claims, characterised in that its glass is hard glass.

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