CN116710410A - Device and method for heating, in particular for bending vitreous glass sheets - Google Patents

Abstract

The invention relates to a device for heating a vitreous glass plate (I), comprising: -a support (1) adapted to horizontally house a glass sheet (I) such that a first main face (O) of the glass sheet (I) faces upwards and a second main face (U) of the glass sheet (I) faces downwards, -a nozzle assembly (2) above the support (1) comprising a plurality of nozzles (3), said nozzles (3) being directed towards the first main face (O) of the glass sheet (I) and being adapted to apply a heated air flow to the first main face (O), wherein-the temperature of the air flow of each nozzle (3) and/or-the pressure of the air flow of each nozzle (3) and/or-the vertical position of each nozzle (3) are adjustable independently of the other nozzles (3).

Description

Device and method for heating, in particular for bending vitreous glass sheets

The present invention relates to an apparatus and method for heating a vitreous glass sheet, in particular for bending a vitreous glass sheet.

Vehicle glazing panels, particularly passenger vehicle glazing panels, are typically curved. Various methods for bending vitreous glass sheets are known. Bending moulds are often used which have a curved active surface and act like a press mould on a softened glass sheet in order to match the shape of the active surface. This can be done under the action of gravity (gravity bending), by suction on a bending die (suction bending) or by pressing between two complementary bending dies (press bending). Combinations of these methods also often occur in multi-stage bending processes. In particular, spherically curved vitreous glass sheets can be produced with high optical quality by this method. For example only, reference may be made to EP1836136B1, US2004107729A1, EP0531152A2, EP1371616A1, EP255422A1, US5906668A, EP1550639A1 and EP1836136B1. Particularly for windshields with high demands on optical quality, a complicated multi-stage bending method is required.

Bending methods are known from WO2017042037A1 and WO2017089070A1, wherein a glass sheet is placed horizontally on a bending mould and an air flow is applied thereto from above.

In conventional bending methods, a glass sheet is heated to a bending temperature in a heating chamber or along a heating section to make it plastically deformable. Here, the heating may be performed by convection or heat radiation. When heated by convection (contact with heated air), the vitreous glass sheet is heated uniformly throughout. When heated by thermal radiation, a temperature profile can be produced, although by appropriate arrangement and design of the heat radiator. However, this temperature profile cannot be formed arbitrarily finely, due to the heat radiator which is usually of considerable scale. The heat transfer efficiency is also limited due to the relatively large distance between the heat sink and the vitreous glass plate. If the vitreous glass plate has an infrared reflective coating, as is commonly used, for example, as a sun protection coating or a heatable coating, heat transfer can also be disturbed.

Conventional bending processes have thus reached a limit, especially when complex glass sheet geometries are to be produced. Such complex glass sheet geometries have localized regions with, for example, strong curvatures (small radii of curvature) and/or strong curvature changes (high gradients of curvature). It is desirable to be able to heat these localized areas very specifically and effectively to higher temperatures to produce complex curvatures with high optical quality.

A bending method is known from WO2020239304A1, in which an additional heating effect is locally achieved on the vitreous glass plate by means of laser radiation.

EP2505563A2 discloses a device for bending a vitreous glass sheet, wherein the vitreous glass sheet is placed horizontally and an air flow is applied from above through two nozzles, wherein the pressure of the air flow of the two nozzles and the vertical position of the two nozzles are independently adjustable.

It is an object of the present invention to provide an improved apparatus and an improved method for heating a vitreous glass sheet. In particular, it should be possible to provide the glass pane with a complex temperature profile and the heating should not be disturbed by the IR reflecting coating which may be present.

According to the invention, the object is achieved by means of a device and a method according to the independent claims. Preferred embodiments are known from the dependent claims.

The apparatus for heating a vitreous glass plate according to the invention comprises a support suitable for horizontally seating the vitreous glass plate. The vitreous glass sheet has first and second major faces and side edge faces extending therebetween. The major faces provide a perspective for passing through the vitreous glass plate and are typically arranged substantially parallel to each other. If the vitreous glass plate is placed horizontally, the first major face faces upward and the second major face downward. This means that the first main face is facing away from the ground and the second main face is facing towards the ground.

The device according to the invention also comprises a nozzle assembly ("upper nozzle assembly") arranged above the support. The nozzle assembly includes a plurality of nozzles. The nozzles are directed downwards, i.e. their outlet openings face the ground. The nozzle is directed towards the support or towards the first main face of the glass sheet if the glass sheet is placed horizontally on the support. The nozzle is adapted to apply a heated air flow to the first main face (more precisely: at least one region of the first main face). A heated gas stream is understood here to mean a gas stream having a temperature higher than the ambient temperature.

In the method according to the invention for heating a vitreous glass sheet, the vitreous glass sheet is placed horizontally on a support such that a first main face of the vitreous glass sheet faces upwards and a second main face faces downwards. The heated gas flow is applied to the first major face of the sheet of vitreous glass by means of a nozzle assembly disposed above the support and comprising a plurality of nozzles directed toward the first major face.

The apparatus and method are described together hereinafter, with the description and preferred embodiments equally directed to the apparatus and method. If the preferred features are described in connection with a method, the resulting device is also preferably designed and adapted accordingly. Conversely, if the preferred features are described in connection with a device, the resulting method is preferably performed accordingly.

In accordance with the present invention,

the temperature and/or the air flow of each nozzle

The pressure and/or the air flow of each nozzle

Vertical position of each nozzle

Is adjustable independently of the other nozzles (and independently as it travels).

Typically and preferably, the initial state of the vitreous glass plate is planar when it is arranged on the support. The two main faces thereof are then arranged substantially plane-parallel. The device and the method according to the invention can be used in a variety of applications. For example, they may be used within the scope of a bending process, thereby providing bending to a vitreous glass sheet. When the glass sheet reaches its bending temperature, it is thereby softened and becomes plastically deformable, and the glass sheet begins to deform. After and/or after the application of the heated gas flow, it is preferable to provide the glass sheet with a bending during this time, since then the gas flow is not only used for heating, but its mechanical force can also be used for deforming the glass sheet. The glass pane can be heated very precisely by the nozzle assembly, wherein the bending temperature can be adjusted in particular locally differently, in each case to the local curvature, in order to ensure high optical quality. In particular, the smaller the local radius of curvature and/or the larger the local curvature gradient, the higher the local bending temperature is selected. The bending temperature is above the so-called transition point of the vitreous glass sheet. The transformation point (transformation point) refers to the temperature at which the viscosity of the vitreous glass sheet allows plastic deformation of the vitreous glass sheet. Suitable bending temperatures are generally from 500 ℃ to 700 ℃, preferably from 550 ℃ to 650 ℃, especially when the vitreous glass sheet is made of soda lime glass.

However, applications are also conceivable in which the vitreous glass plate is heated without producing a change in shape of the vitreous glass plate. Examples of this are baking of printing inks or drying of wet-chemical coatings (e.g. sol-gel coatings). For example, in the case of conventional uniform heating (in particular by means of thermal radiation) for baking black screen-printed matter, as is usual in vehicle glass panes, in particular as a circumferential edge region, the problem frequently arises that optical and even geometrical defects are introduced due to the different heat absorption and heat capacity of the transparent and opaque regions with screen-printed matter, which can be avoided by locally matched heating by convection. Heating by local matching can furthermore influence the formation of mechanical stresses in the glass. The temperature suitable for baking the printing ink is generally from 500 ℃ to 700 ℃.

In a first embodiment, the temperature of the air flow of each nozzle is individually adjustable. Since the individual gas flows can be individually temperature-regulated, very complex and fine temperature profiles can be provided specifically for the glass panes. The nozzles assigned to the areas to be heated more strongly apply a higher temperature air flow to them-the nozzles assigned to the areas to be heated less strongly apply a lower temperature air flow to them.

In a second embodiment, the pressure of the air flow of each nozzle is individually adjustable. Heating the relevant area of the glass sheet with a higher gas pressure is more efficient than with a lower gas pressure (a larger volume of gas per unit time is generated by a higher gas pressure, thereby generating a higher heat input). A complex temperature profile can thus also be achieved by this embodiment, wherein a higher pressure gas flow is applied to the region to be heated more strongly. This embodiment is particularly advantageous if the glass sheet is heated in the range of the bending process, since the gas flow can then be used not only for heating but also for deforming the glass sheet. Complex glass sheet geometries can be achieved by individually adjustable nozzles, wherein a higher air pressure is applied to the region to be more strongly curved (radius of curvature smaller). Thus, not only a temperature curve but also a pressure curve can be generated. Thus, on the one hand, they are heated more strongly and, on the other hand, a higher air pressure results in a more intense deformation.

In the context of the present invention, a curve is understood to mean a local distribution of parameters on a vitreous glass plate. Thus, in the case of a temperature profile, the entire vitreous glass plate does not have a uniform temperature, but rather there are locally different temperatures, wherein the temperature profile describes the temperature distribution. In the case of a pressure curve, a uniform gas flow pressure is not applied to the entire first main surface, but the gas flow pressures are locally different and the pressure curve describes the pressure distribution.

In a third embodiment, the vertical position of each nozzle is individually adjustable. The vertical position may also be referred to as height or elevation and is for example quantitatively expressed as distance from the ground or support. For example, by adjusting the position, the distance of the nozzle from (the first major surface of) the glass-frit-glass plate can be influenced. With smaller distances, the heating of the relevant areas of the vitreous glass plate is more efficient than with larger distances. Thus, a complex temperature profile can also be achieved by this embodiment, wherein the distance from the relevant nozzle is set smaller in the region to be heated more strongly. This embodiment is particularly advantageous if the vitreous glass sheet is heated in the range of the bending process. In this case, the air flow is used not only for heating the vitreous glass plate but also for deforming it. Thus, a smaller distance from the associated nozzle may be selected in the region to be strongly deformed to make the mechanical force transmission more efficient. On the other hand, the position of the nozzle can also be tracked during the bending process so that the distance between the nozzle and the relevant area of the vitreous glass sheet remains substantially constant at all times. Thus, the position of the nozzle continuously matches the increasing deformation of the vitreous glass sheet to keep the mechanical force transmission constant. In this case, the air supply line is preferably formed as a flexible hose to be able to follow the movement of the nozzle.

In further embodiments, any combination of two of the above parameters may be adjusted alone. Thus (2)

The temperature and pressure of the air flow of each nozzle,

temperature of the air flow and vertical position or each nozzle

Pressure of the air flow and vertical position of each nozzle

May be individually adjustable to achieve a combination of the above advantages.

In a particularly advantageous embodiment, all of the abovementioned parameters can be set individually, i.e.

Temperature and air flow of each nozzle

Pressure and air flow of each nozzle

-the vertical position of each nozzle.

The device then has all the advantages described above and can achieve highly complex temperature profiles and, if the heating is carried out within the scope of the bending process, highly complex glass sheet geometries.

According to the invention, at least one, preferably at least two, particularly preferably all three, of the three possible individually adjustable parameters (pressure, temperature, vertical position) can be individually adjusted. The "resolution" of the temperature profile or the pressure profile depends in particular on the number and size of the nozzles, which can be selected according to the requirements in the application case.

Another advantage of the present invention is that the vitreous glass plate is heated by means of air flow through (forced) convection rather than by thermal radiation. Thus, the infrared reflective coating on the vitreous glass plate does not interfere with heating.

A nozzle is a technical device for influencing the gas flow when transferring from a pipe flow into free space. The nozzle is connected to a gas supply line through which a gas flow is supplied to the nozzle and the nozzle forms the end of the gas supply line. Preferably, each nozzle is connected to its own gas supply line independently of the other nozzles, so that each nozzle is assigned exactly one gas supply line and each gas supply line is assigned exactly one nozzle. This facilitates controlling the pressure and/or temperature of the respective gas flows independently of each other. The equipment (heating devices, pressure valves, etc.) required for this can be part of the gas supply line or the nozzle. The gas supply line is typically formed as a hose or conduit. All the gas supply lines are preferably connected to a common facility for generating a gas flow, such as a blower or a compressed air container. The individual nozzles or their respective gas supply lines are preferably provided with shut-off means in order to be able to selectively shut off and open the gas flow of each nozzle.

The gas flow is preferably an air flow, i.e. the gas used is air.

The nozzle has a nozzle wall with two openings (usually opposite each other), an inlet opening facing the gas supply line and an outlet opening facing away from the gas supply line and facing the glass sheet in use. The wall thickness of the nozzle wall is preferably from 0.1mm to 10mm, particularly preferably from 0.5mm to 5mm, in particular from 1mm to 3mm. The nozzle may be formed substantially in a hollow cylinder shape (e.g. as a vertical hollow cylinder) with the inlet opening and the outlet opening forming a bottom surface and the nozzle wall forming a cylinder housing. The length of the nozzle is preferably from 10mm to 1000mm, particularly preferably from 50mm to 500mm, very particularly preferably from 100mm to 250mm.

Within the scope of the invention, there are various possibilities for making the temperature of the air flow of the individual nozzles individually adjustable. In a preferred embodiment, each nozzle is provided with heating means. For this purpose, the nozzle wall itself may be heatable, or there may be heatable means in the nozzle (that is to say in the flow space of the nozzle enclosed by the nozzle wall) around which the air flow flows. Alternatively, however, the preheated gas stream may also have been introduced into the nozzle. For this purpose, the gas supply line of each nozzle is preferably equipped with a heating device, for example a heating coil in the wall of a hose or pipe. Of course, a combination of heating means in the nozzle and heating means in the feed line is also conceivable, wherein this is less preferred due to the increased technical complexity. It is also possible to introduce already preheated air into the air supply line and the final temperature is regulated by the nozzles or heating means in the supply line.

If the pressure of the gas flow of the individual nozzles is individually adjustable, the gas supply line or the nozzles themselves are preferably equipped with means for controlling the amount of gas flowing through, for example with a throttle valve or a throttle flap. Alternatively, each nozzle or a different set of nozzles may be connected to a respective means for generating an air flow, for example a respective hot air blower. Thus, the pressure can be adjusted by the number of revolutions of the blower, respectively.

Another possibility for individually adjusting the pressure of the air flow is that the spray angle of each nozzle is designed to be adjustable independently of the other nozzles. Thus, the concentration of the air flow can be adjusted individually for each nozzle. The pressure and the surface of the glass pane that is hit by the air flow can thus be locally adapted to the requirements of the application. The spray angle is influenced in particular by the cross section of the nozzle in the region of its outlet opening, wherein a narrowing cross section (in the flow direction) leads to a strongly concentrated air flow, while a widening cross section leads to a less concentrated, strongly divergent air flow. For example, a rotatable plate with different openings can be used, which can be moved by rotation between different positions, wherein in each position a nozzle is assigned to one of the openings in each case and serves as its outlet opening. Alternatively, different nozzles can also be arranged on the rotary disk feeder, wherein the respectively required nozzle can be transferred by rotation into the active position, where it is provided with an air flow. It is also possible to provide the nozzle with different accessories, which lead to different spray angles and which are fixed to the nozzle, for example by means of a screw connection or a bayonet connection. Thus, by rotating the plate, the outlet opening of the nozzle can be adjusted, thereby adjusting the spray angle (as long as the opening of the plate is formed such that it produces a different spray angle). However, as an extension of the invention, an adjustable injection angle can also be used in combination with the above-described pressure regulating means (throttle valve or nozzle or throttle flap in its gas supply line).

In order to be able to adjust the vertical position of the nozzles individually, the nozzles are preferably mounted vertically movably independently of each other. The nozzles can then be moved with a gradual curve to keep their distance from the glass surface constant to some extent. Typically, the vitreous glass sheet is curved in a concave shape, which is understood to mean a curvature in which the first main face is made (at least mainly) concave and the second main face is made (at least mainly) convex. In this case, the nozzle is generally moved downward during bending, wherein the more the nozzle is disposed closer to the center of the glass sheet (the greater the bending depth), the more pronounced the movement. The distance between some of the nozzles and the surface of the glass sheet can also be reduced to locally create a stronger air flow effect.

In an advantageous embodiment of the invention, the angle of attack of the nozzles can also be adjusted independently of one another. The angle of attack may be determined, for example, as the angle of the flow direction of the nozzle to the vertical. For this purpose, the nozzles are mounted in a deflectable manner independently of one another. The deflection of the nozzles affects their distance from the glass pane and, in addition, the angle at which the gas flow impinges on the main face of the glass pane. The nozzles can thus be deflected with a gradual bending such that their gas flows always impinge substantially perpendicularly on the glass pane. In the case of a glass pane which is planar in the initial state and provided with a typical concave curvature, the nozzles of the upper nozzle assembly are first aligned vertically and parallel to one another and, with progressive bending, fan out as if they were, that is to say they deflect in the direction of their respective nearest glass pane side edges. If a lower nozzle assembly is present as a support, its nozzles are deflected in the opposite direction towards the center of the glass sheet. While vertical impingement of the gas stream on the vitreous glass plate is generally the case and thus preferred, any other impingement angle may be achieved by the deflectable nozzle depending on the application. A combination is particularly preferred in which the nozzle is mounted so as to be both vertically movable and deflectable. In this way, the distance between the nozzle and the glass sheet and the angle of impingement air flow can be desirably controlled.

The nozzle may have the same cross-sectional area along its entire length, have a widened, tapered or any complex shape. The nozzle preferably tapers, i.e. has a cross-sectional area which is smaller in the outflow direction along the entire length or a part of the length, e.g. the end portion adjoining the outlet opening, so as to concentrate the gas flow as if it were on the first main face of the glass pane. The extent to which the exiting gas flow is concentrated can be quantified as the spray angle of the nozzle, for example, as the angle between the lateral boundary of the exiting gas flow and a central axis extending centrally through the nozzle in the flow direction. The small spray angle results in the gas flow being strongly concentrated and thus only striking a relatively small area of the first main face of the vitreous glass plate, but it has a relatively high pressure against this. The spray angle may also be referred to as the exit angle, or opening angle.

In the sense of the present invention, it is possible to apply an air flow to the entire surface of the vitreous glass plate to heat it, or to only a partial area of the surface. The latter occurs, for example, when, in the region of the glass sheet to be bent particularly strongly (particularly small radius of curvature or particularly high curvature gradient) is to be provided with an elevated temperature or an additional mechanical deformation force relative to the remaining glass sheet by means of an air flow in the region of the bending process. The latter may also occur, for example, when an air stream is used to bake the screen-printed matter into localized areas of the glass sheet surface.

The nozzles of the nozzle assembly are preferably arranged in one dimension (i.e. linearly) or in two dimensions (two-dimensional distribution, i.e. as if distributed in one plane).

The number of nozzles of the upper nozzle assembly is preferably more than two, particularly preferably more than three, very particularly preferably more than five, in particular more than ten.

In a particularly preferred embodiment, the nozzles of the nozzle assembly are arranged linearly in a single row (linear or one-dimensional nozzle assembly).

In another particularly preferred embodiment, the nozzles of the nozzle assembly are arranged in a matrix in a plurality of adjacent rows (two-dimensional nozzle assembly). In this case, the nozzles may be arranged as if they were in rows and columns-but it is also possible to stagger the nozzles of the nozzle rows immediately adjacent to each other.

However, other two-dimensional arrangements are also conceivable. Thus, for example, the nozzles may be arranged in concentric circles. In principle, the nozzles may also be irregularly two-dimensionally arranged. The person skilled in the art can freely choose the arrangement of the nozzles according to the requirements in the particular application.

The terms "one-dimensional" and "two-dimensional" in relation to the nozzle arrangement relate to a top view of the nozzle opening. It is not necessary that all nozzles be arranged in one plane. Furthermore, in embodiments of the invention, the vertical position of the nozzles may be adjusted independently of each other and changed during the process. If the nozzles are not arranged in one plane, a two-dimensional arrangement is derived from the one-dimensional arrangement, and a three-dimensional arrangement is derived from the two-dimensional arrangement. One-dimensional nozzle assemblies may also be referred to as linear nozzle assemblies, while two-dimensional nozzle assemblies may also be referred to as planar nozzle assemblies (or planar distributed nozzle assemblies). In other words, in the one-dimensional nozzle assembly, the orthogonal projection of the nozzles is arranged in one dimension on a horizontal plane, and in the two-dimensional nozzle assembly, the orthogonal projection of the nozzles is arranged in two dimensions on the horizontal plane.

In one embodiment, the (two-dimensional) nozzle assembly is generally at least as large as the vitreous glass plate (more precisely, the major face of the vitreous glass plate). This means that the gas flow can be applied simultaneously to the entire first main face of the glass sheet. In another embodiment, the (one-dimensional or two-dimensional) nozzle assembly is generally smaller than a vitreous glass plate. This means that only a partial region of the first surface is simultaneously subjected to the air flow.

If a gas flow is applied to the entire first major face of the vitreous glass plate, then various embodiments and implementations are possible:

the nozzle assembly is a two-dimensional nozzle assembly at least as large as the vitreous glass plate. The nozzle assembly simultaneously applies an air flow to the entire first surface. In this case, the relative arrangement of the nozzle assembly and the vitreous glass plate may remain constant. However, the nozzle assembly and the glass sheet may also be moved relative to each other to more evenly distribute the gas flow. This relative movement may be achieved by movement of the nozzle assembly or by movement of a (movably mounted) vitreous glass sheet.

The nozzle assembly is a one-dimensional nozzle assembly or a two-dimensional nozzle assembly smaller than a glass sheet. Because it is not possible in this case to apply to the first major face simultaneously, the nozzle assembly and the glass sheet must be moved relative to each other in order to continuously apply the gas flow to the first major face of the glass sheet. To this end, the nozzle assembly may be moved (one or more times) over the fixed-position vitreous glass sheet or the vitreous glass sheet may be moved (one or more times) under the fixed-position nozzle assembly. Of course, the nozzle assembly and the glass sheet may also be movable, but this is technically more complex and therefore less preferred.

If the gas flow is applied only to a partial region of the vitreous glass plate, different embodiments and implementations are equally possible:

the nozzle assembly is a two-dimensional nozzle assembly at least as large as the vitreous glass plate. However, only a part of the nozzles, i.e. those assigned to said part-area of the vitreous glass sheet, are operated. The gas flow is applied simultaneously to the entire partial region.

The nozzle assembly is a one-or two-dimensional nozzle assembly smaller than the vitreous glass plate but as large as said partial area of the vitreous glass plate. In this case, the air flow is also applied simultaneously to the entire partial region.

The nozzle assembly is a one-or two-dimensional nozzle assembly smaller than said partial area of the vitreous glass plate. In order to continuously apply the gas flow to the entire partial region, the vitreous glass plate and the nozzle assembly are moved relative to each other.

In order to flexibly provide a device for different application purposes and different types of vitreous glass sheets, it is interesting to provide a two-dimensional nozzle assembly at least as large as all common glass sheet types. In particular applications, the nozzle assembly is then typically larger than the vitreous glass plate. In order to apply an air flow to the entire first main face at the same time, all nozzles or nozzle portions covering the first main face may be operated. In order to apply an air flow to only a partial region of the first main surface, a nozzle section is operated which covers this partial region.

According to the invention, the vitreous glass plate is placed horizontally on a support. The support may be formed in different ways. In a first preferred embodiment, the support is formed as a curved support mold. The support mold has a curved support surface (contact surface) to which the vitreous glass plate should be matched in shape after heating. Thus, this embodiment can be used in a bending process and the support die is simultaneously a bending die. The support surface is in contact with the second major surface of the vitreous glass plate. In the initial state, the planar glass pane is initially not located over the entire support surface, but only over a portion. After heating to the bending temperature and thus softening, the shape of the glass pane matches the support surface under the influence of gravity on the one hand and the mechanical pressure of the air flow on the other hand, so that the bending of the glass pane is determined by the bent support surface. The support surface preferably has a concave curvature, whereby the vitreous glass plate has a concave curvature (the first major face is concave and the second major face is convex). The support surface may be formed in a frame-like or overall shape.

A support die with a full support surface is also referred to as a full or solid support die. Such a support surface provides for direct contact with most or even the entire glass sheet surface. For a support mold having a frame-like support surface, only the peripheral region of the glass sheet surface is in direct contact with the support surface at or near its side edges, while a majority of the glass sheet is not in direct contact with the tool. Such tools may also be referred to as rings (retaining rings, bending rings) or frames (frame molds). The term "frame-like support surface" within the meaning of the present invention is only used to delimit it from the complete mould. The support surface need not form a complete frame, but may be discontinuous.

In another preferred embodiment, the support is formed as a planar support mold. The support mold has a planar support surface upon which a planar vitreous glass plate is placed. Such a flat support mold can be used in processes where a vitreous glass sheet is to be heated but not bent, such as for baking printing inks. However, if the flat support mold is used only to heat the glass sheet and then the glass sheet is removed from the support mold and fed into the bending tool, it may also be used within the scope of the bending process. Here, the support surface may also be formed in a frame-like shape or entirely.

In another preferred embodiment, the support is formed as a roller conveyor system. The vitreous glass sheet is placed directly on the roller with its second major face in contact with the roller. The vitreous glass sheet moves with the roller conveyor system under the nozzle assembly and is subjected to a gas stream there. Here, the vitreous glass plate may remain stationary disposed below the nozzle assembly during heating. However, the method may also be practiced as a continuous process wherein the glass sheet is continuously moving and the gas flow is continuously applied to the first major face thereof as it passes under the nozzle assembly. This embodiment can also be used in processes where the vitreous glass sheet is to be heated but not bent, such as in baking printing inks. However, it may also be used within the scope of a bending process wherein a roller conveyor system is used only to heat the glass sheet and then remove the glass sheet from the roller conveyor system and send it to a bending tool. Alternatively, a belt conveyor system may be used instead of a roller conveyor system. It is also possible to heat the glass sheet below the nozzle assembly within the scope of the passing system and then run the roller conveyor in a curved shape to bend the softened glass sheet. In this case, rolls may be provided opposite to each other such that the vitreous glass sheet contacts the rolls on both sides in a calender manner.

In another embodiment, the support is formed as another nozzle assembly ("lower nozzle assembly") having a plurality of nozzles directed toward the second major face of the vitreous glass sheet. The lower nozzle assembly is disposed below the vitreous glass plate and the upper nozzle assembly. The nozzles are directed upwards, i.e. their outlet openings face away from the ground, and in use point from below towards the second main face of the glass pane. Nozzles are suitable and are used to apply a gas flow to the second major face whereby the glass sheet appears to be carried in suspension. Thus, the vitreous glass sheet is not directly on the nozzle, but is carried by the gas stream. For this purpose, the gas flow must be appropriately selected to counteract the weight of the glass sheet and the forces exerted on the glass sheet by the upper nozzle assembly. The upper and lower nozzle assemblies are arranged opposite each other with the outlet openings of the nozzles facing each other, in use directed towards the glass sheet located therebetween. Also as in the case of the upper nozzle assembly according to the invention, for the optional lower nozzle assembly, in an advantageous embodiment, for each nozzle at least one parameter, preferably at least two parameters, particularly preferably all three parameters, selected from the temperature of the gas flow, the pressure of the gas flow and the vertical position can be adjusted independently of the other nozzles.

This embodiment as a support for the lower nozzle assembly may be advantageously used in a bending process, wherein it is arranged in suspension between the nozzle assemblies. On the one hand, it is heated by the air flow of the upper and lower nozzle assemblies and, on the other hand, it deforms when it reaches the bending temperature. In addition, it is carried by the air flow of the lower nozzle assembly. In this bending process, the vitreous glass sheet is free of any contact with the bending tool, i.e., it is a contact-free bend. A vitreous glass plate with high optical quality can thus be produced, since no tool embossing or similar surface quality disturbances occur in any way. Furthermore, the heating of the vitreous glass plate is optimally uniform, since the vitreous glass plate is not hidden from below by the supporting mold, the transport rollers, etc. A complex temperature profile may be created by individually adjustable temperatures of the air flows of the individual nozzles of the upper and/or lower nozzle assemblies, wherein the region of the vitreous glass plate to be more strongly curved preferably has a higher bending temperature than the region to be less strongly curved. The individually adjustable pressures of the air flows through the individual nozzles of the upper and/or lower nozzle assembly can likewise influence the temperature profile on the one hand and the mechanical forces for bending can be adapted locally to the respective degrees of curvature on the other hand. Advantageously, a higher pressure is applied to the region of the vitreous glass plate to be bent more strongly than to the region to be bent less strongly. The individually adjustable vertical position of the individual nozzles of the upper and/or lower nozzle assembly can on the one hand also influence the temperature profile and on the other hand can track the nozzles as they are gradually bent (in particular continuously) so that their distance from the glass sheet remains constant. In this way, the forces exerted on the vitreous glass plates by the respective air flows remain constant and the vitreous glass plates can be bent in a very controlled manner. However, the distance between the nozzles of the upper and/or lower nozzle assemblies may also be selected to be smaller in one region of the vitreous glass sheet than in other regions in order to locally produce a stronger heating or bending effect.

In accordance with the present invention, the nozzles of the upper nozzle assembly are adapted to apply a gas flow to the vitreous glass sheet. The gas flow is directed towards the glass sheet, i.e. the direction of the gas flow from the nozzle towards the glass sheet. In an advantageous embodiment, the nozzle is also suitable for applying a suction to the first main face of the vitreous glass plate. Then the air flow may be reversed so that the nozzle draws in air instead of ejecting the air flow. In this way, a negative pressure may be locally generated on the first surface of the vitreous glass plate or an air flow directed from the vitreous glass plate to the nozzle may be generated. The device may then advantageously be operated or the method may be performed such that a part of the nozzles (the first group of nozzles, in particular the majority of the nozzles) apply a gas flow to the first main face of the glass sheet, which is in particular required for heating the glass sheet, in addition for deformation. The suction effect is locally created on the first surface by another part of the nozzles (the second group of nozzles, in particular a few nozzles). In this way, very complex glass sheet geometries can be produced, wherein the suction action locally counteracts the curvature or even can locally produce an opposite curvature.

If the device has a lower nozzle assembly, the nozzles thereof are preferably adapted to apply suction to the second major face of the vitreous glass sheet. The method may then be performed such that a part of the nozzles, in particular the majority of the nozzles, apply an air flow to the second main face of the glass sheet, which is in particular required for carrying and heating the glass sheet, in addition to being used for deformation. By locally generating a suction effect on the second surface by means of a further part of the nozzles, in particular a few nozzles, complex glass sheet geometries can be achieved.

In order to be able to produce the suction effect, the gas supply lines of the individual nozzles (in this case more reasonably gas lines) are connected not only to the (preferably common) means for producing the overpressure, but also to the (preferably common) means for producing the suction effect, for example a blower, a vacuum pump or a venturi nozzle. The gas line also has means to switch between the gas flow and the suction, for example a shut-off device, or a suitable valve, in each of the lines to the gas flow means and the suction means.

The upper nozzle assembly and optionally the lower nozzle assembly may be the only means to heat the vitreous glass sheet. However, the apparatus may also be equipped with conventional heating means, with which the vitreous glass sheet is first preheated in order to subsequently bring it to the target temperature with the nozzle assembly, and optionally to form a temperature profile. In this case, the air flow of the nozzle assembly may additionally heat only a localized region of the glass sheet (e.g., a region where particularly strong bending occurs) or provide its final temperature to the entire glass sheet. The heating means are for example formed as heating sections or heating chambers which are equipped with radiant heaters, convection heating or other heating means. The heating means are preferably arranged above and below the glass pane. For preheating, the glass panes are either arranged stationary in the heating chamber or are continuously moved through the heating chamber or along the heating section during the passing process.

With the device according to the invention, it is possible to heat and optionally bend a single glass pane or a plurality of glass panes simultaneously. In the latter case, two or more vitreous glass plates are stacked one above the other so that their main faces are arranged substantially parallel, in particular plane-parallel, and the stack is placed horizontally on a support. The first major face of the uppermost vitreous glass sheet appears to be the first major face of the stack to which the air flow of the upper nozzle assembly is applied. The second major face of the lowermost vitreous glass sheet appears to be the second major face of the stack, to which the air flow of the lower nozzle assembly is optionally applied.

The vitreous glass plate is preferably made of soda lime glass, but may alternatively be made of other types of glass, such as borosilicate glass or quartz glass. The thickness of the vitreous glass plate is generally 0.1mm to 10mm, preferably 1mm to 5mm.

The vitreous glass sheet is preferably used as a vehicle glass sheet or as a component of a vehicle glass sheet, wherein the heating by means of the nozzle assembly according to the invention is used for bending the vitreous glass sheet, for baking printing ink or for targeted introduction of mechanical stresses. The vitreous glass plate may be an integral part of a composite glass plate in which it is joined to another vitreous glass plate by a thermoplastic interlayer. The intermediate layer is preferably formed from at least one thermoplastic film, in particular based on polyvinyl butyral (PVB), ethylene Vinyl Acetate (EVA) or Polyurethane (PU). Optically clear adhesives (OCA: optically clear adhesive; LOCA: liquid optically clear adhesive) may also be used as an intermediate layer. Composite glass panes are used in particular as windshields or sunroofs, but also increasingly as rear or side panes. However, it may also be used as a monolithic vitreous glass plate, where it is preferably thermally tempered. Monolithic vitreous glass panes are used in particular as roof panes, side panes or rear panes.

Alternatively, however, the vitreous glass sheets can also be used in the field of construction and architecture, for example as glazing for buildings, in building interiors or as parts of furniture, electrical or electronic equipment.

The invention is explained in more detail below with reference to the drawings and the exemplary embodiments. The figures are schematic representations and are not drawn to scale. The drawings are not intended to limit the invention in any way.

Wherein:

figure 1 shows a cross section through one embodiment of the device according to the invention,

figure 2 shows a perspective view of a different nozzle assembly according to the invention,

figure 3 shows a plan view of the nozzle assembly of figure 2,

figure 4 shows a cross-section through two embodiments of a nozzle according to the invention,

figure 5 shows a schematic diagram of the temperature and pressure curves when bending a glass sheet with the method according to the invention,

figure 6 shows a cross section through another embodiment of the device according to the invention in one embodiment of the method according to the invention,

figure 7 shows another cross section of the device from figure 6 in another embodiment of the method according to the invention,

figure 8 shows a cross section of another embodiment of the device according to the invention in another embodiment of the method according to the invention,

Fig. 9 shows a cross section through three embodiments of a nozzle according to the invention.

Fig. 1 shows an exemplary embodiment of the device according to the invention at two points in time when the method according to the invention is carried out. The device comprises a support 1, which support 1 is formed as a curved support mould with an overall support surface. The support surface is curved and faces upwards. The vitreous glass plate I is arranged on a support 1, which in the initial state is planar (fig. 1 a). The vitreous glass plate 1 is, for example, a glass plate of 3.5mm thickness, soda lime glass, which is provided as a side window glass of a motor vehicle. The vitreous glass plate I has a first major face O facing upwards and a second major face U facing downwards.

The vitreous glass plate I should be heated to a bending temperature to plastically deform it. The vitreous glass plate I should then be bent by placing it on a curved support surface of the support 1.

The apparatus further comprises a nozzle assembly 2 formed by a plurality of nozzles 3. The nozzle assembly 2 is positioned above the support 1 and the vitreous glass plate I disposed thereon. Their nozzles are directed downwards so that they can apply an air flow to the first main face O. Each nozzle 3 is connected to a gas supply line 7, such as a hose. The gas supply lines 7 are in turn connected to a common supply line 8, for example a pipe. The air flow can be generated by a ventilator 9, which is branched off via a supply line 8 onto the air supply line 7 and led to the nozzle 3. The gas flow is directed from the nozzle towards the first main face O of the vitreous glass plate I.

The gas flow impinging on the vitreous glass plate I is heated. The vitreous glass plate I is heated to a bending temperature (e.g., 650 ℃) so that it is softened and becomes plastically deformable. The glass pane then begins to rest against the curved support surface of the support 1 under the influence of gravity and is thus curved. The process is also supported by the air flow which exerts a mechanical force on the vitreous glass plate I from above and presses it as if it were pressed into the support surface (fig. 1 b). As a result, on the one hand, the deformation of the vitreous glass plate I is faster and, on the other hand, more complex bends (for example with small radii of curvature that occur locally) can be produced, which cannot be achieved by pure gravity bending.

According to the invention, at least one of the following parameters can be adjusted for each nozzle 3 independently of the other nozzles 3:

the temperature T of the air flow of the nozzle 3,

the pressure p of the air flow of the nozzle 3,

the vertical position of the nozzle 3.

On the one hand, complex temperature profiles can thus be produced in order to adapt the bending temperature locally to the requirements, wherein, for example, the region of the glass pane I to be bent more strongly is heated to a higher temperature. On the other hand, the forces acting on the glass pane can be locally adapted, wherein, for example, a stronger air flow is applied to the region of the glass pane I that is to be bent more strongly. Thus, a vitreous glass plate with high optical quality and complex geometry can be obtained by means of the device according to the invention and the method according to the invention implemented therewith.

Fig. 2 (perspective view) and fig. 3 (top view) show respective details of different embodiments of the nozzle assembly 2 of the device according to the invention. In fig. 2 a/3 a, the nozzles are arranged linearly along a single row. Such a nozzle assembly 2 may be used to heat a localized area of the glass sheet I or to heat the entire glass sheet I by moving the glass sheet I under the nozzle assembly 2 such that the first major face is continuously coated with a gas stream.

Fig. 2 b/3 b show a two-dimensional nozzle assembly 2. The nozzles 3 are arranged in a plurality of rows positioned adjacent to each other. The arrangement of nozzles 3 is matrix-like and as if it were made up of rows and columns.

Fig. 2 c/3 c also show a two-dimensional nozzle assembly 2 having a plurality of rows positioned adjacent to each other. However, unlike the embodiment of fig. 2b, adjacent rows of nozzles 3 are arranged offset to achieve a denser arrangement of nozzles 3 and to apply a more uniform air flow to the first major face O.

With a two-dimensional nozzle assembly, the air flow can be applied simultaneously to the entire first main face O, or only in a localized area. The number of nozzles in the figures is exemplary only and is intended to illustrate the principles. If a real vehicle glazing is to be heated simultaneously, there will typically be a significantly greater number of nozzles.

Fig. 4 shows a cross section through two embodiments of the nozzle 3, wherein the temperature of the gas streams directed from them towards the glass pane I can be adjusted individually. For this purpose, the nozzle 3 is equipped with a heating device 6.

The nozzle 3 has a nozzle wall 3a with two openings opposite each other: an inlet opening (upper part in the figure) through which the gas flow from the gas supply line 7 enters the nozzle 3 and an outlet opening (lower part in the figure) facing the glass sheet. The nozzle 3 has a narrowing end portion adjoining the outlet opening to concentrate the air flow.

The nozzle wall 3a itself may be used to heat the air flow. Thus, in the embodiment according to fig. 4a, a heating conductor is embedded as heating means 6 in the nozzle wall 3a, so that the nozzle wall 3a can be heated to heat the air flow. However, as shown in fig. 4b, the heating device 6 may also be arranged in the interior of the cavity of the nozzle 3. The air flow flows around the heating means 6, whereby it can be heated. The heating device 6 is a rod-like member including, for example, a heating coil. The electrical connections required for the power supply of the heating means 6 are not shown in the figures. Instead of embedded heating conductors or coils, external heating cartridges may also be used to adjust the temperature of the nozzle wall 3a or the rod-shaped heating means 6. The air supply line 7 can additionally be designed to be heatable, so that air which has been pre-conditioned is led to the nozzle 3.

Fig. 5 shows an exemplary application of the method according to the invention. The glass pane I should be heated and bent, which has a very strong curvature in the edge region (fig. 5 a). If the nozzles 3 of the device according to the invention are designed such that the gas flows through them can be heated individually, the vitreous glass plate I can have a temperature profile in which the region to be strongly bent has a higher temperature than the region to be strongly bent (fig. 5 b). In principle, a low bending temperature is advantageous for the optical quality of the vitreous glass plate I. The temperature profile may be selected such that each region of the vitreous glass plate I has exactly the bending temperature required to give it the desired bending. In this way, an optimal optical quality is achieved.

If the nozzles 3 of the device according to the invention are designed such that the pressure of the gas flow through them can be adjusted individually, a pressure curve can be applied to the vitreous glass plate I. The pressure applied to the areas to be more strongly curved is higher than the areas to be less strongly curved (fig. 5 c), because their bending requires more force.

Fig. 6 shows a further exemplary embodiment of the device according to the invention at two points in time when the method according to the invention is carried out. The support 1 is formed as a further nozzle assembly 4, which is referred to as a lower nozzle assembly. The lower nozzle assembly 4 likewise comprises a plurality of nozzles 5 which are directed from below towards the second main face U of the glass pane I and which apply an air flow to the second main face U, through which the glass pane I is carried. The gas flow is applied to the first major face O of the vitreous glass plate I by the upper nozzle assembly 2. The vitreous glass plate I is thus placed as if suspended between the nozzle assemblies 2, 4. It is heated by the heated air flow to a bending temperature (fig. 6 a) and can then be deformed by the mechanical force of the air flow (fig. 6 b). The high optical quality of the vitreous glass plate I is ensured by such bending without contact with the bending tool.

The nozzles 3, 5 of the two nozzle assemblies 2, 4 can be moved vertically independently of the other nozzles 3, 5 of the respective nozzle assemblies 2, 4. As the vitreous glass plate I is gradually bent, the position of the nozzles 3, 5 is changed in such a way that their distance from the vitreous glass plate I remains substantially constant. Thus, the force exerted by each nozzle on the vitreous glass sheet I remains substantially constant during the bending process.

In addition to the vertical position, the temperature of the air flow of each nozzle 3, 5 can preferably be adjusted individually, and particularly preferably the pressure of the air flow of each nozzle 3, 5 can also be adjusted individually. A flexible temperature and pressure profile can thus be produced on the glass pane I.

Fig. 7 shows a cross section through the device according to fig. 6 in a further embodiment of the method according to the invention. Here, the distance between all the nozzles 3, 5 and the vitreous glass plate I is not kept constant. Instead, a part of the nozzles 3 of the upper nozzle assembly 2 (the second and third nozzles 3 on the left in the drawing) are very close to the vitreous glass plate I in order to make their action on the vitreous glass plate I more efficient, i.e. to apply a greater mechanical force. In this way, the bending force can be locally increased, for example, in order to deform the region of the glass pane I to be bent more strongly or to correct bending errors.

Of course, multiple sub-groups of nozzles 3 may also be located more strongly adjacent to the vitreous glass plate I. One or more sub-groups of nozzles 5 of the lower nozzle assembly 4 may also be more strongly adjacent to the vitreous glass plate I.

Fig. 8 shows a further exemplary embodiment of the device according to the invention at two points in time when the method according to the invention is carried out. The planar vitreous glass plate I is arranged on a support 1 (fig. 8 a), which support 1 is formed as a support mould with a curved support surface. Heated to a bending temperature, against which the vitreous glass plate I rests and is bent by the influence of gravity on the one hand and of the air flow of the nozzle assembly 2 on the other hand (fig. 8 b). The nozzles 3 of the nozzle assembly 2 can be moved vertically independently of each other so that their positions can match the gradual bending of the vitreous glass sheet I. Furthermore, the nozzles 3 can deflect independently of each other. As the vitreous glass sheets I are progressively bent, they appear to fan out so that the angle of impact of their air flow on the first main face O remains substantially constant, in particular substantially vertical. The force exerted by each nozzle 3 on the vitreous glass plate I is thus kept substantially constant during the bending process.

In addition to the relative position, the temperature of the air flow of each nozzle 3 is preferably also individually adjustable, and particularly preferably the pressure of the air flow of each nozzle 3 is also individually adjustable.

Fig. 9 shows a cross section through three embodiments of a nozzle 3 with a nozzle wall 3 a. The nozzle 3 differs in the type of outlet opening. In fig. 9 (a) the nozzle tapers in the end portion towards the outlet, in fig. 9 (b) the nozzle cross section is kept constant, in fig. 9 (c) the nozzle widens in the end portion towards the outlet opening. The spray angle α of the nozzle 3 can be influenced by the outlet opening, for example as an angular measurement between the lateral boundary of the outgoing gas flow and a central axis extending through the nozzle 3 in the flow direction, as indicated in the figure. The spray angle α is a measure of how much the exiting gas flow is concentrated or spread, which in turn affects the effect on the first major face O of the glass sheet (fig. 9 (a) small spray angle α, concentrated gas flow, high pressure, small applied face; fig. 9 (c) large spray angle α, spread gas flow, low pressure, large applied face; fig. 9 (b) located therebetween).

The nozzle 3 may have a fixed outlet opening. In an advantageous embodiment, each nozzle 3 is provided with an adjustable outlet opening, so that its spray angle α can be adjusted independently of the other nozzles 3. The flexibility of the device is thereby further increased, since the injection angle α can be locally adjusted.

The exemplary embodiments shown, in particular the combinations of features shown therein, are to be understood as illustrative only and should not be construed as limiting in any way. Thus, for example, it is also possible that not all nozzles 3, 5 of the upper nozzle assembly 2 and of the possibly lower nozzle assembly 4 direct a gas flow towards the vitreous glass plate I, but that a suction effect is locally created by a subgroup of the nozzles 3, 5. Hereby it is possible to achieve a still more complex glass sheet geometry and a still faster bending process. Likewise, for example, a vertically movable nozzle 2 as in fig. 6 may be combined with other supports 1, such as a curved support die, a flat support die or a roller conveyor system as in fig. 1.

List of reference numerals:

(1) Support for a vehicle

(2) (upper) nozzle assembly

(3) Nozzle of (upper) nozzle assembly 2

(3a) Nozzle wall of nozzle 3

(4) (lower) nozzle assembly

(5) Nozzle of (lower) nozzle assembly 4

(6) Nozzle 3 heating device

(7) Air supply line for nozzle 3

(8) Supply line for gas supply line 7

(9) Blower fan

(I) Vitreous glass plate

(O) first major surface of vitreous glass plate I

(U) second major surface of vitreous glass plate I

Spray angle of (α) nozzle 3.

Claims (16)

1. Apparatus for heating a vitreous glass plate (I), comprising:

A support (1) adapted to house the vitreous glass plate (I) horizontally, such that a first main face (O) of the vitreous glass plate (I) faces upwards and a second main face (U) of the vitreous glass plate (I) faces downwards,

a nozzle assembly (2) above the support (1) comprising a plurality of nozzles (3), said nozzles (3) being directed towards the first main face (O) of the vitreous glass plate (I) and being adapted to apply a heated air flow to the first main face (O),

wherein the method comprises the steps of

-temperature and/or air flow of each nozzle (3)

-pressure and/or flow of air per nozzle (3)

-vertical position of each nozzle (3)

Is adjustable independently of the other nozzles (3).

2. The device according to claim 1, wherein the nozzle assembly (2) comprises more than two nozzles (3), preferably more than three nozzles (3), particularly preferably more than five nozzles (3), arranged in a linear or planar distribution.

3. The device according to claim 1 or 2, wherein the nozzles (3) of the nozzle assembly (2) are arranged in a linear row or in a matrix in a plurality of adjacent rows.

4. A device according to any one of claims 1 to 3, wherein each nozzle (3) is provided with heating means (6) such that the temperature of the air flow of each nozzle (3) is adjustable independently of the other nozzles (3).

5. The apparatus according to any one of claims 1 to 4, wherein the nozzles (3) are vertically movable independently of each other to adjust their vertical positions independently of each other.

6. The apparatus of any one of claims 1 to 5, wherein

-each nozzle (3) or the gas supply line (7) connected thereto is provided with a throttle valve or a throttle flap or

The injection angle (alpha) of each nozzle (3) is independently adjustable,

to regulate the pressure of its air flow independently of the other nozzles (3).

7. A device according to any one of claims 1 to 6, wherein the nozzles (3) are deflectable independently of each other, such that their angles of attack are adjustable independently of each other.

8. The device according to any one of claims 1 to 7, wherein the bearing (1) is formed as a curved support mould with a frame-like or full support surface.

9. The device according to any one of claims 1 to 7, wherein the support (1) is formed as a planar support mould with a frame-like or full support surface or as a roller conveyor.

10. The device according to any one of claims 1 to 7, wherein the support (1) is formed as a further nozzle assembly (4) having a plurality of nozzles (5), the nozzles (5) being directed towards the second main face (U) of the glass sheet (I) and being adapted to apply an air flow to the second main face (U) and thereby carry the glass sheet (I),

Among them, preferred is

-temperature and/or air flow of each nozzle (5)

-pressure and/or flow of air per nozzle (5)

-vertical position of each nozzle (5)

Is adjustable independently of the other nozzles (5) of the further nozzle assembly (4).

11. The device according to any one of claims 1 to 10, wherein the nozzle (3) is further adapted to exert a suction effect on the first main face (O).

12. Method for heating a vitreous glass pane (I), wherein

Placing the glass pane (I) horizontally on the support (1) such that a first main face (O) of the glass pane (I) faces upwards and a second main face (U) of the glass pane (I) faces downwards,

-a first main face (O) of the vitreous glass plate (I) applying a heating air flow by means of a nozzle assembly (2), said nozzle assembly (2) being arranged above the support (1) and comprising a plurality of nozzles (3) directed towards the first main face (O),

wherein the method comprises the steps of

-temperature and/or air flow of each nozzle (3)

-pressure and/or flow of air per nozzle (3)

-vertical position of each nozzle (3)

Is adjustable independently of the other nozzles (3).

13. Method according to claim 12, wherein the vitreous glass plate (I) is planar in the initial state and has a curvature during and/or after the application of the heating gas flow.

14. Method according to claim 13, wherein a higher temperature and/or higher pressure gas flow is applied to the regions of the glass sheet (I) having a stronger curvature than to the regions of the glass sheet (I) having a smaller stronger curvature, and/or wherein the nozzles (3) assigned to them have a smaller distance from the first main face (O).

15. A method according to claim 13 or 14, wherein the vertical position of the nozzles (3) is changed during bending of the vitreous glass sheet (I) such that their distance from the first main face (O) remains substantially constant.

16. A method according to claims 12 to 15, wherein the air flow is applied to the first main face (O) of the vitreous glass plate (I) by means of a first set of nozzles (3) and the suction effect is applied by means of a second set of nozzles (3).