DE102006059358B4 - Flat glass, process for its preparation and device for tempering a Floatbadgehäuses - Google Patents

Abstract

contraption (40) for tempering a Floatbadgehäuses (11) with a ceiling wall (15), a bottom wall (12), two end walls (13, 14) and two side walls (16, 17), characterized in that at least below each side wall (16, 17) at least one lower air distribution channel (43, 44) and at least above each side wall (16, 17) at least one air collecting channel (47, 48) is arranged, and that the air distribution channel (43, 44) is connected to the outlet of at least one ventilation device (41).

Description

The The invention relates to a device for tempering a Floatbadgehäuses.

The production of flat glass by the float process, known as float glass, has been known since the last century and is essentially based on the fundamental intellectual property rights of Pilkington ( US 3,083,551 . DE 147 19 50 ).

At the Float method leaves one liquid glass, which is brought about by means of a gutter from the working trough, on a bath of molten metal, generally tin flow. Of the Volume flow of the glass is over a movable slider regulated, with its setting under other things, the glass thickness is set. In the flow direction of Glases seen behind the slider 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 stiffens. Subsequently, will the solidified glass ribbon removed from the metal bath.

The Float glasses made in this way, usually a thickness of less than 1.5 mm are used as thin glass substrates, among others used for the production of flat screens, z. B. of plasma screens (PDP = Plasma Display Panel), field emission screens (FED = Field Emission Display), TFT Liquid Crystal Displays (TFT = Thin Film Transistor), STN liquid crystal screens (STN = Super Twisted Nematic), Plasma Assisted Liquid Crystal Displays (PALC = Plasma assisted liquid crystal), electro-luminescence displays (EL) and the like or for the production of thin-film solar cells.

at The flat screens will vary depending on the type of display two glass panes either a thin layer of a liquid crystal compound introduced or it will be on the front and back of the back or front disc each applied dielectric layers, from which cells are formed in which phosphors are housed.

It Here it is important that the layer thickness of the liquid crystal layer or the thickness of the dielectric layer is strictly adhered to, especially with large ones Dimensions of a screen no annoying color distortions or similarity deviations occur. As the layer thicknesses, currently about 30 microns, getting smaller and the screens always grow, This condition is becoming increasingly important.

Even though Float glass is ideally suited for display applications due to its fire-polished surface is, it is in today's required large substrate formats with edge lengths from above 1800 mm not yet possible Display glass to produce the float process, the differences in thickness below 50 μm lie.

A statement for the Emergence of thickness variations in float glass is the presence of currents in the float bath. These very complex currents are the result of interacting mechanically and thermally induced Currents. Inso far comes the temperature control Significant importance within the Floatbadvorrichtung.

The Floatbadvorrichtung essentially comprises the Floatbadwanne with Bottom wall and tub side walls, in which the molten metal is located, the float bath roof (Roof) as well as the side walls (Side ceilings), which are attached to the roof. Between the side walls of the Badger and the tub side walls Sidewall boxes are provided, the z. B. openings to carry out Have top scooters.

The Floatbadvorrichtung thus has a box-shaped Floatbadgehäuse, which is in a production hall. Before the float bath device are other facilities for the production of molten glass and behind the Floatbadvorrichtung are facilities for processing arranged the produced glass ribbon.

by virtue of the high temperatures of molten glass, metal bath and atmosphere above the Metal bath and over the glass ribbon is heated the Floatbadgehäuse accordingly, so that the outer walls of the Floatbadgehäuses also have a high temperature. Through the radiated from the housing Heat is a considerable heat load generated in the production hall.

There the temperature inside the building, in the Floatbad device is located, both from the daily changing ones Temperatures (daily cycle) as well as the temperatures of the different Seasons (annual cycle) is also affected, the temperature inside the float bath device through the various cycles affected. this leads to to that the narrow temperature ranges within the Floatbadvorrichtung can not be met, which has a negative effect on the glass quality.

An additional jacket of Floatbadgehäuses, with the aim to be independent of the temperature fluctuations of the environment, can not be attached, since the outside skin of the housing must be accessible for maintenance and repair work.

It is therefore an object of the invention, a device for temperature control to indicate a Floatbadgehäuses.

The Task is with a device for tempering a Floatbadgehäuses with a ceiling wall, a bottom wall, two end walls and two side walls solved, the characterized in that at least below each side wall at least a lower air distribution channel and at least above each side wall at least one air collecting channel is arranged, wherein the air distribution channel connected to the output of at least one ventilation unit.

The Ventilation device is preferred with a fan and according to one particular embodiment equipped with a device for tempering the air.

The Tempering device, for example, a cooling device for cooling the over the air collection channel recirculated air recirculation or a mixing chamber for mixing colder outside air with the circulating air.

Of the Air collection channel may preferably be connected to the input of the ventilation unit and / or to an exhaust air device, that the heated air outward emits.

The fan is preferably designed controllable, so that the flow velocity or the amount of air per unit of time can be adjusted.

Above the Ceiling wall is preferably additional at least one upper air distribution channel arranged to the Ventilation unit connected is. The upper air distribution channel is preferably in a middle Area of the ceiling wall arranged. The air flows from the upper air distribution duct preferably down to the ceiling wall. The advantage exists in that only one upper distribution channel for the entire Ceiling wall is sufficient.

A advantageous arrangement of air distribution channels and air collection channels consists in this, in the longitudinal direction the Floatbadgehäuses to arrange.

Around a differentiated cooling the Floatbadgehäuses carry out to be able to It is advantageous if each air distribution channel in at least two Air distribution channel sections is divided, which are different with air Temperatures and / or different amounts of air per unit time can be acted upon. The air channel distribution channels are fluid, z. B. by partitions from each other separated.

at this embodiment it is advantageous in the respective air supply pipes to control valves to provide the amount of air. Also, according to the number of Air distribution channel sections provided a corresponding number of ventilation equipment become. It makes it possible for the Temperature and / or the amounts of air per unit of time in the individual Individually set sections. According to the number of Air distribution channel sections may also have a corresponding number provided by ventilation circuits become.

The Ventilation unit points preferably a control unit on, to the temperature sensor are connected. The temperature sensors can be on or in the side walls and / or be arranged on or in the ceiling wall.

Around the air targeted to the outside of the housing to be able to judge are preferably adjustable at least at the lower air distribution channels Provided means for flow guidance.

The lower air distribution channels are preferably covered with a walk-in grid so that they can be entered by the operating and maintenance personnel to Carry out the necessary work on the outer skin of the Floatbadgehäuses can.

The Process for the production of flat glass provides that at least Parts of the outside the Floatbadgehäuses by means of at least one air flow be overflowed with at least one predetermined temperature to form an air jacket.

This Air jacket has the advantage that its temperature and / or its Amount of air per unit of time can be controlled so that the daily and annual cycles can be counteracted accordingly. By these cycles caused uncontrolled temperature fluctuations inside the Floatbadgehäuses with the result of thickness variations of the glass ribbon can be effective be avoided.

One Another advantage of the air jacket is that the outer skin the Floatbadgehäuses after as before accessible is to carry out the required work.

The temperature of the supplied air is adjusted such that the air flow forming the air jacket has a maximum temperature of 30 ° C to 40 ° C, so that the operating personnel in can work within the air jacket without special protective clothing. Due to the heating of the air flow when sweeping the outside of the Floatbadgehäuses the temperature of the supplied air is set correspondingly lower.

The Temperature of the air flow is set to a temperature that is at the annual minimum the temperatures of the environment of Floatbadgehäuses oriented. Since the Floatbadvorrichtung in a building is housed, is preferably the lowest temperature of the Year inside the building as a guideline for the setting of the temperature of the air flow based. Where the temperature within the building must be measured, hangs down Other from the structural conditions. Orientation on the Annual minimum has the advantage that the device for tempering the Floatbadgehäuses only one cooling device and not one too Heating device got to.

The cooling capacity the air flow not only over the temperature but also or alternatively via the flow velocity and / or over the Air quantity / time unit can be set. Preferably, the airflow a speed of 2 to 3 m per second. At this flow rate can easily on the outer skin the Floatbadgehäuses to be worked.

at the usual Dimensions of Floatbadgehäusen, at about 30 m in length and 15 m height are, is the thickness of the air jacket preferably 30 to 70 cm, in particular 40 to 60 cm, to tear off the air flow to prevent. A tearing off the air flow would have to Result that the insulation effect of the air jacket is interrupted.

The Air is flowing on the housing side walls of bottom up. Since the air heats up when the housing side walls overflow and therefore with the thermal ascends, this effect is due to the predetermined flow direction supported.

Also The Floatbaddach is provided with an air jacket. According to one particular embodiment is provided that the air in a middle area from above on the roof of the Floatbadgehäuses is passed and flows from there on both sides to the outside.

The Air is extracted in the area above the side walls. The suction in this area has the advantage that both the on the side wall of the housing flowing upwards as well over the roof laterally outwards flowing Air can be sucked out together. The suction devices can therefore be used optimally.

The airflow gets into flow sections divided, wherein at least two flow sections with different air Temperatures and / or flow rates and / or Air quantity / time unit are applied.

It is provided, the air flow perpendicular to the flow direction, this means longitudinal the side walls and the roof to divide into at least two flow sections, wherein at least two flow sections be acted upon with different amounts of air per unit time. The different amounts of air per unit of time, for example by a change the thickness of the air jacket at unchanged flow velocity or at unchanged Thickness of the air jacket by change the flow velocity will be realized.

It is advantageous if the width of the flow sections to the width the Floatbadabschnitte be adjusted within the housing. The float bath sections, of which usually seven or eight are provided and the as bays are usually called with different Temperatures driven so that it is advantageous, the Floatbadgehäuse not uniform temperature in all sections. The subdivision in flow sections with different temperatures or different air volumes opened per unit of time also the possibility to specifically influence the temperatures in the bays from the outside, to z. B. on currents to act in the metal bath and to improve in this way the glass ribbon quality.

The process is particularly suitable for the production of borosilicate glasses, alkali-free glasses, aluminosilicate glasses, aluminolithium silicate glasses and precursor glasses for glass-ceramic,
Particularly suitable is the method for producing borosilicate glass, z. For fire protection applications, having a composition of (all of the following in terms of weight percent based on oxide):
SiO ₂ 70-85, B ₂ O ₃ 7-13, Na ₂ O + K ₂ O + Li ₂ O 3-8, MgO + CaO + SrO 0-3, Al ₂ O ₃ 2-7,
for the preparation of alkali-free alumino (boro) silicate glass with a composition of
SiO ₂ 50-70, B ₂ O ₃ ≤15, Al ₂ O ₃ 10-25, MgO 0-10, CaO 0-12, SrO 0-12, BaO 0-15, with MgO + CaO + SiO + BaO 8 -26, ZnO 0-10, ZrO ₂ 0-5, TiO ₂ 0-5, SnO ₂ 0-2,
z. B. for the production of display glass, in particular with a composition of
SiO ₂ > 55-65, B ₂ O ₃ 5-11, Al ₂ O ₃ > 14-25, MgO 0-8, CaO 0-8, SrO 0-8, BaO ≤ 10 with MgO + CaO + SrO + BaO 8-21, ZnO 0-5, ZrO ₂ 0-2, TiO ₂ 0-3, SnO ₂ 0-2,
in particular SiO ₂ > 58-65, B ₂ O ₃ > 6-10.5, Al ₂ O ₃ > 14-25, MgO 0 - <3, CaO 0-9, BaO> 3-8 with MgO + CaO + BaO 8-18, ZnO 0 - <2, As ₂ O ₃ -free, Sb ₂ O ₃ -free,
preferably Zn oxide, Ce oxide, Zr oxide, Ti oxide free.

It is also particularly suitable for the production of various green glasses for glass-ceramic, such. B. with
SiO ₂ 55-69, Al ₂ O ₃ 19-25, Li ₂ O 3-5, Na ₂ O 0-1.5, K ₂ O 0-1.5, Σ Na ₂ O + K ₂ O 0.2 -2, MgO 0.1-2.2, CaO 0-15, SrO 0-1.5, BaO 0-2.5, Σ MgO + CaO + SrO + BaO below 6, ZnO 0-1.5, TiO ₂ 1-5, ZrO ₂ 1-2.5, SnO ₂ 0 to less than 1, Σ TiO ₂ + SrO + SnO _{2 2} 2.5-5, P ₂ O ₅ 0-3
or a glass-ceramic precursor glass having a composition of
SiO ₂ 55-75, Al ₂ O ₃ 15-30, Li ₂ O 2.5-6, Σ Na ₂ O + K ₂ O less than 6, Σ MgO + CaO + SrO + BaO less than 6, B ₂ O ₃ 0 to less than 4, ΣTiO ₂ + ZrO ₂ less than 2
or a glass-ceramic precursor glass having a composition of
SiO ₂ 60-72, Al ₂ O ₃ 18-28, Li ₂ O 3-6, Σ Na ₂ O + K ₂ O 0.2-2, Σ MgO + CaO + SrO + BaO less than 6, ZnO 0-1 , 5, B ₂ O ₃ 0 to less than 4, SnO 0.1-1.5, ΣTiO ₂ + ZrO ₂ less than 2, P ₂ O ₅ 0-3, F 0-2.

The Flat glass made in a float bath made by a Floatbadgehäuse is surrounded, wherein at least parts of the outside of the Floatbadgehäuses means at least one air flow at least one predetermined temperature is overflowed to form an air jacket, shows significantly lower thickness variations than flat glass, which in float baths is produced, the Floatbadgehäuse no air jacket for isolation having. The thickness variations are less than 50 microns.

exemplary embodiments The invention will be explained in more detail with reference to the drawings.

It demonstrate:

1 a perspective view of a float glass plant,

2 . 3 Vertical sections through the Floatbadvorrichtung along the line II-II according to two embodiments and

4 an enlarged detail of a lower air distribution channel.

In the 1 is a float bath facility 1 schematically illustrated, which is a Floatbadvorrichtung 10 which has a device 2 upstream of the melt and a device 3 downstream of the glass band processing.

The float bath device 10 has a Floatbadgehäuse 11 on, that's a bottom wall 12 , two end walls 13 and 14 , a ceiling wall 15 and on the long sides sidewalls 16 and 17 having. The side walls 16 and 17 can in sidewall sections 16a , b, c, which are the Floatbadabschnitten inside the Floatbadgehäuses 11 which are known as bays. A typical float bath tub is usually divided into seven or eight bays. For simplicity, the illustrated sidewall 16 by way of example only in three side wall sections 16a , b, c divided.

Around the Floatbadgehäuse 11 with a cloak 60 to provide at least the ceiling wall 15 and the side walls 16 and 17 Wrapped is a device 40 for tempering the Floatbadgehäuses 11 intended. This device 40 includes lower air distribution channels 43 and 44 that are below the side walls 16 . 17 are arranged, of which in the 1 due to the selected perspective view, only the air distribution channel 43 you can see. The corresponding air distribution channel 44 is located below the rear side wall 17 ,

The lower air distribution duct 43 , which may for example consist of a tube with a round cross-section, at its upper side air outlet openings 72 are arranged in the representation shown here according to the division of the side wall into side wall sections 16a to c in correspondingly long air distribution channel sections 43a . 43b . 43c divided, which are fluidly separated from each other. Every section 43a . 43b . 43c is at its own air supply pipe 46 connected, wherein in the air supply pipe 46 for controlling the amount of air / time unit valves 146 are arranged. The from the air distribution channel 43 flowing upwards and on the side wall 16 for cooling the same passing air is indicated by the corresponding arrows.

Above the ceiling wall 15 is in the middle area another, upper air distribution channel 45 arranged, the air outlet openings are provided at the bottom, so that the air on top of the ceiling wall 15 is directed. Also the upper air distribution duct 45 is in sections 45a . 45b . 45c divided, each section 45a , b, c fluidly separated from the adjacent section and to an air supply pipe 46 connected. The air flows on the ceiling wall 15 on both sides in the direction of the side walls 16 and 17 ,

All air distribution channels 43 . 44 and 45 are in the longitudinal direction of the Floatbadgehäuses 11 arranged.

The during the Vorbefiströmens on the housing walls 16 . 17 and the ceiling wall 15 warming air is provided by air collection channels 47 . 48 sucked in the vertical direction above the side walls 16 . 17 are arranged, and also in the longitudinal direction of the Floatbadgehäuses 11 extend. Again, these are pipes with corresponding air inlet openings, which are arranged in the embodiment shown here on the underside and respectively on the side of the air flow on the ceiling wall 15 is facing. The air collection channels 47 . 48 are on air return pipes 49 connected.

The air mantle 60 envelops the Floatbadgehäuse 11 on the side walls 16 and 17 as well as on the ceiling wall 15 , It is thus formed a closed air wall, wherein in the flow sections 61 . 62 . 63 different temperatures and / or air quantities per unit time can be adjusted so that one of the side wall sections 16a , b, c adapted cooling of the outer skin of Floatbadgehäuses 11 is possible.

In the 2 is a section along the line II-II through the Floatbadgehäuse 11 shown. Inside the float bath enclosure 11 passing through the float bath tub 20 , the side walls 16 . 17 and the roof 24 is formed, is the liquid metal 28 on which the glass band 29 swims.

The float bath tub 20 has a tub bottom 21 and tub side walls 22 , The float bath roof 24 has a roof wall 25 as well as roof side walls 26 where between the roof side walls 26 and tub side walls 22 Sidewall boxes 27 are arranged.

The lower air distribution channels 43 . 44 are via air supply pipes 46 to a ventilation unit 41 connected, which is a facility 30 for tempering the air and a fan 31 has to circulate the cooling air. Also the upper air distribution duct 45 is via an air supply pipe 46 ' with the ventilation unit 41 connected. The air collection channels 47 . 48 are via air return pipes 49 with the ventilation unit 41 connected. The recirculated warm air is inside the ventilation unit 41 cooled and over the air supply pipes 46 the air distribution channels 43 . 44 and 45 fed again.

It is also possible to use the individual air distribution duct sections 43a . 43b . 43c such as 45a . 45b and 45c each to their own ventilation units 41 connect to set different air temperatures and / or different amounts of air per unit time can.

On the side walls 16 respectively. 17 the Floatbadgehäuses 11 are temperature sensors 50 attached to a control unit 42 , the component of the ventilation unit 41 can be electrically connected.

In the 3 a further embodiment is shown, which differs from the in 2 characterized in that the air return tubes 49 to an exhaust device 90 connected, that the recirculated, heated air through the exhaust pipe 91 to the outside air outside of the housing, in which the Floatbadgehäuse is located.

The outside air is taken from the ventilation unit 41 over the exit pipe 100 sucked. Between the output pipe 100 and the exhaust device 90 is a bypass line 101 with valve 102 arranged to mix warm air, especially in winter, with cold outside air.

All valves 102 . 146 are electrically connected to the control unit 42 connected. The electrical connection lines are not shown in the figures for reasons of clarity.

In the 4 is an enlarged view of a lower air distribution channel 43 shown. This air distribution channel 43 is below the float bath enclosure 11 arranged and has on its upper side air outlet openings 72 in which as a guide 70 adjustable slats 71 are arranged to direct the flow of air on the side wall 16 to be able to judge. Above the lower air distribution channel 43 is a grid 80 arranged, which is permeable to air and accessible by the operator. The thickness of the air jacket 60 is denoted by D and is usually about 50 cm.

1

Floatbadanlage

2

Facility for melt production

3

Facility for glass strip processing

10

Floatbadvorrichtung

11

Floatbadgehäuse

12

bottom wall

13

bulkhead

14

bulkhead

15

ceiling wall

16

Side wall

16a, 16b, 16c

Sidewall portion

17

Side wall

20

Floatbadwanne

21

Wannenboden

22

When sidewall

24

Floatbaddach

25

roof wall

26

Roof sidewall

27

Sidewall box

28

liquid metal

29

glass tape

30

Facility for tempering the air

31

fan

40

contraption for tempering the Floatbadgehäuses

41

Ventilation unit

42

control unit

43

lower Air distribution channel

43a, 43b, 43c

Air distribution duct section

44

lower Air distribution channel

45

upper Air distribution channel

45a, 45b, 45c

Air distribution duct section

46

air supply

46 '

air supply

47

Air collection channel

48

Air collection channel

49

Air recirculation pipe

50

temperature sensor

60

air jacket

61

flow sections

62

flow sections

63

flow sections

70

guide means

71

lamella

72

Air outlet opening

80

walkable grid

90

Exhaust fan

91

exhaust pipe

100

outlet pipe

101

Bypass pipe

102

Valve

146

Valve

Claims (12)

Contraption ( 40 ) for tempering a Floatbadgehäuses ( 11 ) with a ceiling wall ( 15 ), a bottom wall ( 12 ), two end walls ( 13 . 14 ) and two side walls ( 16 . 17 ), characterized in that at least below each side wall ( 16 . 17 ) at least one lower air distribution channel ( 43 . 44 ) and at least above each side wall ( 16 . 17 ) at least one air collection channel ( 47 . 48 ), and that the air distribution channel ( 43 . 44 ) to the outlet of at least one ventilation device ( 41 ) connected. Apparatus according to claim 1, characterized in that the ventilation device ( 41 ) a device for tempering the air ( 30 ) having. Apparatus according to claim 1 or 2, characterized in that the air collection channel ( 47 . 48 ) to the entrance of the ventilation unit ( 41 ) connected. Device according to one of claims 1 to 3, characterized in that the air collecting channel ( 47 . 48 ) to an exhaust air device ( 90 ) connected. Device according to one of claims 1 to 4, characterized in that above the ceiling wall ( 15 ) at least one upper air distribution channel ( 45 ) which is connected to the ventilation device ( 41 ) connected. Apparatus according to claim 5, characterized in that the upper air distribution channel ( 45 ) in a middle area above the ceiling wall ( 15 ) is arranged. Device according to one of claims 1 to 6, characterized in that the air distribution channels ( 43 . 44 . 45 ) and the air collection channels ( 47 . 48 ) in the longitudinal direction of the Floatbadgehäuses ( 11 ). Device according to one of claims 1 to 7, characterized in that each air distribution channel ( 43 . 44 . 45 ) into at least two air distribution channel sections ( 43a . 43b . 43c . 45a . 45b . 45c ), which can be acted upon with air of different temperature and / or different amounts of air per unit time. Device according to one of claims 1 to 8, characterized in that the ventilation device ( 41 ) a control device ( 42 ) or connected to a control unit, to the temperature sensor ( 50 ) are connected. Device according to one of claims 1 to 9, characterized in that the temperature sensors ( 50 ) on or in the side walls ( 16 . 17 ) and / or on or in the ceiling wall ( 15 ) are arranged. Device according to one of claims 1 to 10, characterized in that at least the lower air distribution channels ( 43 . 44 ) adjustable means ( 70 ) have flow guidance. Device according to one of claims 1 to 11, characterized in that the lower air distribution channels ( 43 . 44 ) with a walk-in grid ( 80 ) are covered.