WO2008110573A1 - Float bath apparatus and method for the production of flat glass - Google Patents

Abstract

The invention describes a float bath apparatus (10) which is divided into float bath sections or bays (1-8) in a longitudinal direction. The float bath apparatus (10) has a float bath housing (11) which has a float bath tub (12), a float bath roof, and side walls (24, 20). Located in said float bath tub (12) is a float bath (16) of molten metal for the production of a glass strip (19) floating on the float bath (16). A suction device (30) is provided for the aspiration of a forming gas atmosphere contained in the float bath housing (11), wherein the suction device (30) comprises at least one suction conduit (32) with at least one suction opening in at least one side wall (14, 20). The suction opening is a slit opening (34) extending in a horizontal direction. A method for the production of flat glass is also described.

Description

 Float bath apparatus and method for producing flat glass

The invention also relates to a method for producing flat glass, in particular TFT glass, according to the preamble of claim 25.

The production of flat glass by the float process, so-called float glass, has been known since the last century and is essentially based on the fundamental industrial property rights of Pilkington (US Pat. No. 3,083,551, DE 147 19 50).

In the float process, liquid glass, which is produced by means of a trough from the working trough, is allowed to flow onto a bath of molten metal, generally tin. The flow rate of the glass is controlled by a movable slide, with its setting, among other things, the glass thickness is set. As seen in the direction of flow of the glass behind the slide is the pouring lip, from which the molten glass flows continuously to the metal bath, where the glass melt is formed into a dimensionally stable glass ribbon and solidifies. Subsequently, the solidified glass ribbon is removed from the metal bath.

The float bath is located in a float bath enclosure, which is usually divided into 7 or 8 float bath sections, known as bays.

The float glasses produced in this way, which generally have a thickness of less than 1, 5 mm, are used as thin glass substrates, inter alia, for the production of flat screens, z. B. of plasma screens (PDP = plasma Display Panel), Field Emission Display (FED), TFT Thin Film Transistor (TFT), STN (Super Twisted Nematic) Liquid Crystal Display (LCD), Plasma Assisted Liquid Crystal Display ( PALC = Plasma Assisted Liquid Crystal), electro-luminescence displays (EL) and the like or for the production of thin-film solar cells.

In the flat panel displays, depending on the type of display, either a thin layer of liquid crystal compound is placed between two sheets of glass or dielectric layers are respectively formed on the front and back surfaces of the back and front sheets, respectively, from which cells are formed containing phosphors ,

It is important in this case that the layer thickness of the liquid-crystal layer or the thickness of the dielectric layer is exactly adhered to, so that no disturbing color distortions or similarity deviations occur, in particular for large dimensions of a screen. Since the layer thicknesses, currently about 30 microns, smaller and smaller and the screens are getting bigger, this condition is becoming increasingly important.

The surface quality of the float glass is affected by surface defects called top bacons, which are caused by deposits of Sn and SnO ₂ particles on the glass ribbon when using a tin bath. Despite the flooding of the interior with forming gas (typical composition 12% H ₂ , 88% N ₂ ), the atmosphere above the float bath contains residual amounts of oxygen which penetrate into the tin bath and form SnO ₂ particles there. With increasing bath temperature, both tin and tin oxide evaporate and enriches the atmosphere, with the result that the tin and tin oxide particles can precipitate on the glass ribbon.

From WO 2005-097692 it is known to suck the atmosphere and thus the tin oxide particles by means of suction pipes, which are arranged in the side wall.

From JP 11-302024, JP 50-3414 and JP 11-021137 Floatbadvorrichtungen are known which have ventilation systems. About the float bath roof forming gas from N ₂ and H _{2 is introduced} into the interior of the Floatbadgehäuses, being set by suspended partitions a certain flow within the Floatbadgehäuses. The introduced forming gas sets an overpressure in the interior. Through vent pipes in the side walls, the gas atmosphere is discharged to the outside. Active suction devices are not described.

From GB 1 217 047 a float bath is known, in which above the edge of the glass band are arranged horizontally extending tubes which have slot-shaped openings. By means of this pipe system, the forming gas is sucked off and introduced via the ceiling of the Floatbadvorrichtung in the interior of the float bath. By means of this device, the glass ribbon is stretched and the edge of the glass band stabilized.

In this arrangement, in the region immediately above the free Floatbadoberfläche a flow in the forming gas, which is directed towards the glass ribbon out. As a result, the forming gas with the highest concentrations of vaporized, metal-containing gases is sucked towards the glass ribbon. Thus, the danger of surface defects on the glass ribbon increases. In all known solutions it has been found that the extraction of the forming gas atmosphere is not effective enough to significantly reduce the number and / or size of the surface defects.

It is therefore an object of the invention to provide a Floatbadvorrichtung, with the number and / or size of the surface defects on the glass ribbon, which is produced by the float process, can be reduced. It is also an object of the invention to provide a corresponding method for the production of flat glass.

The object is achieved with a float bath device, which is characterized in that the suction opening is a slot opening extending in the horizontal direction.

The slot opening preferably extends in the float bath longitudinal direction, i. in the direction of the glass ribbon flow. Preferably, the slot opening extends parallel to the side wall and preferably parallel to the Floatbadoberfläche. The slot opening has a minimum distance from the glass band edge in the horizontal direction.

On the free surface of the molten float bath, ie in the region between the glass ribbon and the side wall, evaporate metal-containing gases, such as tin-containing gases. Without special measures, the metal-containing gases spread in the entire Formiergasatmosphäre. These gases or even reaction, condensation or sublimation of these gases reach in appreciable flow rates in particular in the Formiergasatmosphäre, which is located above the glass ribbon, and finally lead to the mentioned surface defects on the glass ribbon surface.

The advantage of the invention is that the Formiergasatmosphäre is preferably sucked from a large-scale, contiguous area immediately above the free surface of the molten metal. In this range, the concentration of vaporized metal-containing gases in the forming gas atmosphere is highest. By the suction described, the metal-containing gases and the harmful particles formed from these gases from the Formiergasatmosphäre be removed more effectively and completely than with round suction tubes, which are arranged distributed over greater distances along the side walls of the Floatbadgehäuses.

The horizontal distance A _{5 of} the slot opening from the glass band edge is at least 30%, preferably at least 50%, in particular at least 75% of the respective distance A _{4 of} the glass band edge to the side wall.

Preferably, the slot opening is arranged in the side wall.

Preferably, in each case at least one slot opening is arranged in at least two float bath sections, preferably in the two opposite side walls. This ensures that, starting from the center of the glass band immediately above the glass band, flows on both sides are used in each case to the nearest slot opening. Especially in the areas immediately above the glass band edges and the adjacent free metal surface, the flows are directed away from the glass ribbon and towards the slot opening. This will cause a transport of the vaporized, metal-containing gases and harmful particles from the Formiergasbereich with high concentrations of vaporized, metal-containing gases in the area above the glass ribbon task according largely prevented.

Preferably, the slot openings are arranged at least in the first two Floatbadabschnitten. In Floatbadabschnitten where the hot forming takes place, these are in particular the Floatbadabschnitte 1 and 2, optionally also Floatbadabschnitt 3, the temperature of the float bath is highest, so there is the enrichment of the atmosphere with harmful particles is greatest. By means of suction through slit openings in the float bath sections, the effectiveness of the decontamination of the atmosphere can be significantly increased.

Preferably, at least two slot openings are arranged in the horizontal direction next to one another.

The distance between two slit openings should be minimized as far as possible and should be less than 10 cm, in order not to allow any dead spaces in which harmful particles can not be detected by the extraction system.

Preferably, the slot openings extend a total of at least 50% of the length of a Floatbadabschnittes. Preferably, the slot openings extend over at least 70%, more preferably over at least 80% of the length of the float bath section.

Preferably, the slot openings extend for a total of at least 50% of the length of the entire float bath. Preferably, the slot openings extend over 70%, in particular over 80% of the length of the entire float bath. With this arrangement of the suction openings, the Formiergasatmosphäre is sucked over the entire surface of the metal bath, so that no dead spaces can arise in which accumulate the harmful particles and may possibly rise up inside the Floatbadgehäuses. From there, the particles generally return down the center of the housing and settle on the glass ribbon. A large-scale extraction over almost the entire length of the side wall, in particular over both side walls, prevents this adverse effect and leads to a significant decrease in the so-called top bacon.

Flat glass made in a float bath apparatus of the invention shows a significantly lower number of surface defects. The number of surface defects per m ² could be reduced on average from 30 - 50 top bacon / m ² to 0 - 20 top bacon / m ² . In addition, it has been shown that the size of the surface defects decreases to a diameter below 25 μm.

Preferably, the horizontal length of the slot opening is 30 cm to 150 cm.

The cross-sectional area of the slot opening is advantageously 20 to 40 cm ² . This means that in the claimed lengths of the slot openings, the vertical width of the slot opening may be in the range of 2 to 10 mm. By maintaining these values, a uniform flow over the entire length of the slot opening is maintained within the slot opening.

The slot opening should be arranged as close as possible to the metal bath surface in order to be able to extract as much of the particles as possible. Preferably, the lower edge of the slot opening is between 5 cm and 10 cm above the mirror of the float bath arranged (vertical distance A ₃ ).

Preferably, the suction line in the side wall on a slope from the inside out. This has the advantage that in the suction condensed particles drain to the outside and thus not contaminate the metal bath.

Preferably, the suction line has a slot nozzle. Slot nozzles essentially have a triangular shape in plan view. Towards the outside, the cross section tapers and merges into the cross section of the connected suction line. In the side view, the cross-section expands starting from the slot opening at the transition to the cross-section of the connected suction line. The slot nozzle may be a separate component or may be integrally formed on the suction tube forming the suction line.

A slot-shaped nozzle can be arranged at a small distance above the Floatbadspiegel, so that opens the possibility to suck the gas atmosphere immediately above the float.

Preferably, in the slot nozzle for the taper an opening angle a of 14 ° to 40 °, preferably 18 ° to 35 °, more preferably 20 ° to 30 ° and for the expansion of an opening angle ß of 2 ° to 10 °, preferably 3 ° to 8 °, particularly preferably 5 ° to 7 °, to ensure a uniform over the length of the slot flow within the slot nozzle, so that the pressure losses kept as low as possible and dead spaces with the risk of deposition of condensates are avoided. The angle a is the angle between the tapered side walls the slot nozzle in plan view and the angle ß of the angle between the side walls of the slot nozzle in the side view.

Preferably, the slot nozzle is arranged in a side wall box.

The side wall box preferably has two shaped blocks, in particular of refractory material, which delimit at least the slot nozzle. The slit nozzle is formed in this case in the mold bricks, wherein preferably the dividing line between the two shaped bricks passes through the slit nozzle.

Preferably, a plurality of suction tubes are arranged distributed along the two side walls. The suction power through the suction tubes is preferably individually adjustable via the corresponding suction means. This embodiment offers the advantage that the different temperature conditions inside the float bath housing can be easily taken into account. Thus, in the hotter areas, a larger volume of gas per unit time can be extracted than is necessary in the colder sections.

Advantageously, at least one suction tube is arranged in at least two sections (bays) of the float bath tub in the two opposite side walls.

Preferably, the suction line has a suction pipe extending in the direction of the float bath mirror. This embodiment is used in particular where the suction line is arranged in a side wall box, the type must be arranged conditionally at a greater distance to the metal bath surface. The arrangement of a suction or multiple suction lines in the sidewall boxes allows quick replacement of the suction lines, for example, if smaller or larger cross-sections or a larger or smaller number of suction lines in the respective side wall area are needed. Such an adaptation may become necessary if, under certain circumstances, the temperature conditions within the float bath housing and thus the concentration of the particles should change.

Preferably, the suction means is an injector pump. The injector pump generates a vacuum at the outlet of the suction tube.

Injector pumps have two inputs and one output and consist in principle of two nested tubes, which are referred to as inner tube and outer tube. The inner tube ends in the outer tube and has an outlet nozzle. The suction fluid exits under the full line pressure from the outlet nozzle in the outer tube and thereby tears the fluid to be sucked, d. H. the Formiergasatmosphäre from the second input with. This happens due to the generated negative pressure. For example, a water jet pump works according to this principle.

Since the suction power of the injector pump can be easily adjusted with high accuracy via the pressure of the suction fluid, the desired adaptation to the different concentrations of the particles in the interior of the floating bath housing is possible. The accuracy is ± 5 m ³ (i.N) / h. The term m ³ (i.N) is understood to mean a standard cubic meter which is defined in DIN 1343. A standard cubic meter is the amount that one cubic meter of gas at a pressure from 1, 01325, a humidity of 0% (dry gas) and a temperature of 0 ⁰ C corresponds. Preferably, the injector pump is operated with compressed air as a suction fluid.

Accordingly, the injector pump is preferably connected to at least one compressed air generator.

Furthermore, the compressed air generator may be connected to a control device for controlling the pressure of the compressed air or the compressed air generator has such a control device.

It is also possible that a control device for controlling the pressure of the compressed air is arranged between the injector pump and the compressed air generator. Such a control device may be for example a compressed air valve. Preferably, such a compressed air valve is arranged in front of each injector pump so that each injector pump can be adjusted individually.

One or more suction lines can be connected to an injector pump. The group-wise arrangement of suction lines lends itself to when the suction power of each Floatbadabschnittes should be set individually. If a plurality of suction lines are provided within a Floatbadabschnittes to be sucked through the individually set gas quantities per unit time, preferably each suction is connected to a separate injector.

The control device is preferably connected to at least one temperature sensor, which is arranged in the interior of the float bath. The corresponding temperature changes can thus directly via the control device in the relevant Absaugleistung be implemented, which is necessary to ensure optimal extraction of the particles.

The method for producing flat glass, in particular TFT glass, provides that the Formiergasatmosphäre is sucked through slot openings.

Preferably, the Formiergasatmosphäre is sucked in a horizontal distance A ₅ from the edge of the glass ribbon, which is at least 30%, preferably at least 50%, in particular at least 75% of the horizontal distance between the edge of the glass ribbon and the side wall.

The Formiergasatmosphäre is preferably sucked at a distance A ₃ between 5 cm and 10 cm above the free Floatbadoberfläche.

Preferably, the Formiergasatmosphäre is sucked through at least one slot opening.

It is preferable to perform the extraction at several points along the Floatbadvorrichtung, wherein in at least two Floatbadabschnitten (Bays) of the Floatbadwanne the Formiergasatmosphäre is sucked.

Preferably, the Formiergasatmosphäre, preferably at both sidewalls of the Floatbadgehäuses, over at least 50%, in particular at least 70%, particularly preferably sucked off over at least 80% of the Floatbadlänge.

It is also advantageous that the amount of gas extracted in each Floatbadabschnitt per unit time is set in dependence of the temperature of the Floatbadabschnittes. Exemplary embodiments of the invention are explained below with reference to the drawings.

Show it

Fig. 1 is a plan view of a float bath with glass ribbon;

FIG. 2 shows a side view of a section of a side wall of a float bath housing according to a further embodiment; FIG.

3 shows a section along the line III-III in Figure 2;

4 shows a cross section corresponding to FIG. 3 according to a further embodiment;

4a shows a cross section corresponding to Figure 3 and Figure 4 according to another embodiment;

Fig. 5 is a perspective view of a

Sidewall box;

Fig. 6 is a horizontal section through that shown in Fig. 5

slot;

7 is a side view of a section of a side wall according to another embodiment;

8 is a side view of a section of a side wall according to a further embodiment; 9 shows a cross section through that shown in FIG

Side wall along the line IX-IX according to another embodiment;

9a shows a cross section through that shown in FIG

Side wall along the line IX-IX according to another embodiment;

10 is a partial vertical section through the edge of a float bath with an injector pump.

FIG. 11 shows a further sectional view similar to FIG. 10 according to a further embodiment; FIG.

Fig. 12 is a side view of a section of a

Side wall with a slot nozzle according to another embodiment;

13 shows a vertical section through a side wall according to a further embodiment; and

Fig. 14 is a vertical section through a side wall according to another embodiment.

FIG. 1 shows the plan view of a float bath tub 12 of a float bath apparatus 10 located in a float bath housing 11, which is subdivided into float bath sections which are provided with the so-called bay numbers 1 to 8. The float bath tub 12 is filled with a bath 16 of liquid metal, in particular tin. On the bath 16 floats a glass ribbon 18, which is pulled off in the direction of the arrow. The area between the edge 19 of the glass ribbon 18 and the side walls 14 of the Floatbadwanne 12 forms the free Float bath surface from which tin and tin oxide can evaporate. The vaporized metal and metal oxide form particles. These particles then deposit on the surface of the glass ribbon 18 and cause the previously described top bacon.

In the side walls of the Floatbadvorrichtung 10 suction lines 32 of a suction device 30 are arranged in the form of suction tubes, with only a portion of the suction lines 32 is shown for clarity. In Bay number 2, a suction line 32 is shown in the right side wall, representative of further suction lines, which is connected to an injector pump 40, which is supplied by a compressed air generator 60 via a compressed air line 49. To control the compressed air is before the injector 40 as

Control device, a control valve 64 is provided. The control of the valve 64 may be manual or electrical.

In Bay number 3 is also a suction line 32 and in Bay number 4, two suction lines 32 are shown. The two suction lines 32 from Bay 4 are connected to a common Injektorpumpe 40. Both injector pumps 40 for Bay 3 and Bay 4 are connected via a common compressed air line 49 to the compressed air generator 60, which is electrically connected to a control device 62. This control device 62 is connected via an electrical connection line 52 with temperature sensors 50, which are arranged on the inside of the side walls 14 of the Floatbadgehäuses 11. The embodiments shown in FIG. 1 merely represent examples of applications of suction lines 32 and injector pumps 40 as well as of control valves 64 and control devices 62. FIG. 2 shows a detail of a side wall 20 of the float bath housing 11. It is the side view on the inner surface of the side wall, which in the area shown consists of side wall boxes 22 which are arranged on the side wall 14 of the float bath tub. Each side wall boxes 22 has a slot-shaped suction opening 34. The slot-shaped suction openings 34 are arranged close to each other with a distance of less than 10 cm and close above the mirror 17 of the metal bath 16 at a distance of about 5 cm. The suction openings 34 are located in the lower region of the side wall boxes. The dense arrangement of the slot-shaped suction openings 34 has the advantage that the Formiergasatmosphäre can be sucked almost over the entire region of the side wall without dead spaces arise in which the harmful particles can accumulate.

FIG. 3 shows a section along the line III-III through the side wall 20 shown in FIG. The slot-shaped suction opening 34 belongs to the suction line 32, which tapers with respect to the cross section to the cross section of the outer suction tube 33.

FIG. 4 shows a further embodiment in which the suction line 32 within the side wall box 22 has a downward gradient. Sucked particles can condense within the sidewall box 22 and thus within the suction line 32 to droplets. Due to the gradient, these condensed particles can not get back into the Floatbadgehäuse and thus into the metal bath 16, but these condensed droplets flow out into the outer suction pipe 33 from.

In Figure 4a, yet another embodiment is shown in which the suction line 32 within the side wall box 22 with the Angle ß widened between the lower and the upper side wall of the suction. In addition, the distance A ₃ between the lower edge of the suction opening 34 and the surface of the metal bath 16 is shown.

In the figure 5 is a perspective view of a side wall box 22 is shown, which is formed in the embodiment shown here of two refractory bricks 23 and 24. In these stones 23, 24 a slot nozzle 31 is formed. The dividing line 25 between the two shaped bricks 23, 24 extends through the slot nozzle 31, which brings with it corresponding manufacturing advantages. A horizontal section through the slot nozzle 31 is shown in FIG. It can be seen that the opening angle a of the slot nozzle 31 is defined by the two boundary walls of the slot nozzle 31. This angle is in the representation shown here at σ = 20 °.

In the figure 7, another embodiment of a side wall 20 with side wall boxes 22 is shown. The side wall boxes 22 may for example be formed as in the figure 5 and each having a slot nozzle 31. The arrangement of such side wall boxes 22 with slot nozzles 31 is not consistently over the entire Floatbadlänge possible because at certain points within the float bath from outside to inside so-called top rollers must be introduced, which must have a corresponding mobility. In the middle side wall boxes 22, such a top roller 70 is exemplified and indicated schematically. In order to be able to extract the area under the top rollers so that no dead spaces can occur there, in the embodiment shown here, a cover element 80 is provided which has a horizontal middle part 82 and downwardly inclined sections 83. The inclined portions 83 extend to just above the mirror 17 of the Float bath. The cover elements may extend to the edge of the glass ribbon. Due to the inclined arrangement so contaminated forming gas from the area under the top roller 70 can also be sucked.

FIG. 8 shows a further embodiment. The suction tubes 32 have a downwardly curved suction nozzle 38, on which in the horizontal direction a tube 36 is arranged, which has a slot-shaped opening 34.

FIG. 9 shows a section along the line IX-IX. In a modification to Figure 8, the slot-shaped suction opening 34 is provided on the underside of the tube 36.

FIG. 9a again shows a section along the line IX-IX. In a modification to Figure 8, the slot-shaped suction opening 34 is now arranged obliquely downward pointing to the metal bath 16. In addition, the distance A ₄ between the side wall 22 and the edge of the glass ribbon 18 is entered. The distance A ₅ denotes the distance between the suction opening 34 and the edge of the glass ribbon 18th

FIG. 10 shows a partial vertical section through a float bath tub 12 with bottom wall 13 and side wall 14. On the side wall 14 of the Floatbadwanne 12, a side wall boxes 22 is shown with suction 32.

The suction line 32 discharges above the float bath 16 into the interior of the float bath housing 11. Outwardly, the suction line 32 opens into the injector pump 40, which consists of an outer tube 42 and an inner tube 44, at the upper end of which a nozzle 46 is arranged. The inner tube 44 is connected to a compressed air generator 60, which in turn to a control device 62 electrically connected. Via the electrical connection line 52, the control device 62 is connected to the arranged on the inside of the wall 20 temperature sensor 50. The compressed air generated in the compressed air generator 60 flows into the inner tube 44 and then from the nozzle 46 into the interior of the outer tube 42 a. It is therefore in the outer tube 42 in the mouth region of the suction line 32 generates a negative pressure, due to which the Formiergasatmosphäre is sucked from the interior of the Floatbadgehäuses 11. Compressed air and gas atmosphere from the interior of the Floatbadgehäuses 11 are discharged upwards together through the discharge pipe 48.

FIG. 11 shows a further embodiment. At the suction pipe 32, a suction nozzle 38 is arranged, which allows to suck the Formiergasatmosphäre from the interior of the Floatbadgehäuses 11 immediately above the Floatbadoberfläche. In a modification to the illustration of FIG. 10, a compressed air valve 64 is arranged as a control device between the compressed air generator 60 and the injector pump 40 in order to control the compressed air and thus adjust the suction power of the injector pump 40.

FIG. 12 shows a further embodiment in which the suction tube 32 has a slit nozzle 31 with slot-shaped opening 34 extending into the interior. This makes it possible to bring the suction opening closer to the mirror 17 of the float bath 16.

In the figures 13 and 14 further embodiments are shown in which a proboscis 38 is provided, which extends in the figure 13 vertically downwards on the inner wall of the side wall box 22, so that the suction opening disposed directly above the mirror 17 of the float bath 16 is. In the figure 14, the trunk 34 executed kinked, so that the end portion is oriented horizontally and the suction opening 34 allows a horizontal suction.

LIST OF REFERENCE NUMBERS

Bay number

Bay number

Bay number

Bay number

Bay number

Bay number

Bay number

Bay number

Floatbadvorrichtung

Floatbadgehäuse

Floatbadwanne

bottom wall

Side wall

bath

Floatbadspiegel

glass tape

Edge of the glass ribbon

Side wall Side wall box Form stone Form stone Dividing line

Suction device Slot nozzle Suction line outer suction tube suction

pipe

proboscis

injector pump

outer tube

inner tube

jet

drain pipe

Compressed air line

Temperature sensor electrical connection cable

Air compressor

control device

control valve

Toproller

cover

midsection

side panel

Claims

claims 1. Floatbadvorrichtung (10), in the longitudinal direction in Comprising a float bath housing (11) having a float bath tub (12), a float bath roof and side walls (24, 20), wherein a float bath (16) is provided in the float bath tub (12). made of liquid metal is for producing a floating on the float bath (16) glass ribbon (18), and with a suction device (30) for sucking off a forming gas atmosphere located in the float bath housing (11), the suction device (30) having at least one suction line (32) with at least one suction opening in at least one side wall (14, 20) and at least one suction means outside the float bath housing ( 11), characterized the suction opening is a slot opening (34) extending in the horizontal direction. 2. Device according to claim 1, characterized in that the slot opening (34) has a horizontal distance A ₅ from the edge of the glass band (18) which is at least 30% of the horizontal distance A ₄ between the edge of the glass band (18) and the Sidewall (22) is. 3. Apparatus according to claim 1 or 2, characterized in that the slot opening (34) in the side wall (14, 20) is arranged. 4. Device according to one of claims 1 to 3, characterized in that in at least two Floatbadabschnitten (1 to 8) in each case at least one slot opening (34) is arranged. 5. Apparatus according to claim 4, characterized in that the slot openings (34) at least in the first two Floatbadabschnitten (1, 2) are arranged. 6. Device according to one of claims 1 to 5, characterized in that at least two slot openings (34) are arranged side by side in the horizontal direction. 7. Device according to one of claims 1 to 6, characterized in that the slot openings (34) extend over a total of at least 50% of the length of a Floatbadabschnittes. 8. Device according to one of claims 1 to 7, characterized in that the slot openings (34) extend over a total of at least 50% of the length of the float bath (16). 9. Device according to one of claims 1 to 8, characterized in that the horizontal length of the slot opening (34) is 30 cm to 150 cm. 10. Device according to one of claims 1 to 9, characterized in that the cross-sectional area of the slot opening (34) is 20 to 40 cm ² . 11. Device according to one of claims 1 to 10, characterized in that the lower edge of the slot opening (34) between 5 cm and 10 cm above the mirror (17) of the float bath (16) is arranged. 12. Device according to one of claims 1 to 11, characterized in that the horizontal distance A ₅ between the slot opening (34) and the edge (28) of the glass band (18) at least 50% of the horizontal distance A ₄ between the side wall (22 ) and the edge (28) of the glass ribbon. 13. Device according to one of claims 1 to 12, characterized in that the horizontal distance A ₅ between the slot opening (34) and the edge (28) of the glass ribbon (18) at least 75% of the horizontal distance A ₄ between the side wall (22 ) and the edge (28) of the glass ribbon. 14. Device according to one of claims 1 to 13, characterized in that the suction line (32) in the side wall (20) has a gradient from the inside to the outside. 15. Device according to one of claims 1 to 14, characterized in that the suction line (32) has a slot opening (34) having slot nozzle (31). 16. The apparatus according to claim 15, characterized in that the slot nozzle between the tapered side walls of the slot nozzle an angle a of 14 ° to 40 ° in plan view and between the side walls of the slot nozzle in the side view an angle ß of 2 ° to 10 ° having. 17. The apparatus of claim 15 or 16, characterized in that the slot nozzle (31) in a side wall boxes (22) is arranged. 18. The apparatus according to claim 17, characterized in that the side wall boxes (22) has two shaped blocks (23, 24) which delimit at least the slot nozzle (31). 19. Device according to one of claims 1 to 18, characterized in that the suction means is an injector pump (40) which generates a negative pressure at the outlet of the suction tube (32). 20. The apparatus according to claim 19, characterized in that the Injektorpumpe (40) is connected to at least one compressed air generator (60). 21. Device according to claim 19 or 20, characterized in that the compressed air generator (60) has at least one control device (62) for controlling the pressure of the compressed air or is connected to at least one such control device (62). 22. Device according to one of claims 19 to 21, characterized in that between the injector pump (40) and compressed air generator (60) at least one control device (62) is arranged for controlling the pressure of the compressed air. 23. The device according to claim 22, characterized in that the control device (62) is a control valve (64). 24. Device according to one of claims 21 to 23, characterized in that the control device (62) to at least one temperature sensor (50) is connected, which is arranged in the interior of the Floatbadgehäuses (11). 25. A process for the production of flat glass, in particular of TFT glass, in which in a sidewalls Floatbadgehäuse under a Formiergasatmosphäre a molten glass poured onto a liquid metal bath, formed a glass ribbon and the glass ribbon is lifted from the metal bath, wherein the Formiergasatmosphäre over the metal over at least one side wall of the Floatbadgehäuses is sucked off, characterized in that the Formiergasatmosphäre is sucked in a slot shape in the horizontal direction. 26. The method according to claim 25, characterized in that the Formiergasatmosphäre is absorbed in a horizontal distance A ₅ from the edge of the glass ribbon, which is at least 30% of the horizontal distance A ₄ between the edge of the glass ribbon and the side wall. 27. The method according to claim 26, characterized in that the Formiergasatmosphäre is sucked at several points along the side wall. 28. The method according to any one of claims 26 or 27, characterized in that the Formiergasatmosphäre in at least two Floatbadabschnitten (Bays) of the Floatbadgehäuses is sucked like a slit. 29. The method according to any one of claims 26 to 28, characterized in that the Formiergasatmosphäre is sucked off over at least 50% of the Floatbadlänge. 0. The method according to any one of claims 26 to 29, characterized in that the extracted gas amount per unit time is set in each Floatbadabschnitt depending on the temperature of the Floatbadabschnittes.