DE1496016B2 - Device for hardening flat glass - Google Patents

Description

The invention relates to a device for hardening flat glass, with mutually opposite Thermally conductive elements and a device to bring them into thermal conductive contact with the opposite Areas of the flat glass at a temperature above the deformation point to bring, and with a cooling device connected to the heat conducting elements in order to connect to the glass-remote sides of the heat conducting elements a desired reference temperature to control the Maintain heat conduction speed from the flat glass through the heat conducting elements.

According to a known method for tempering glass, the glass is heated to a temperature above the deformation point or pour point of the glass is heated, after which the surfaces of the heated Glass can be subjected to the action of a quenchant, usually cold air, to produce a To generate temperature difference between the surfaces and the interior of the glass, while the Glass is cooled above a deformation point.

These known methods have the disadvantage that the increase in the degree of hardening of the glass by increasing the pressure with which the gaseous quenchant is directed against the glass can lead to the fact that an embossing or marking of the glass surface is produced, and it exists also an effective upper limit on the degree of hardness which can be produced in a glass article can, due to the difficulty of the detergent used from the range of to to effectively remove hardening glass articles. The gaseous quenchant is a poor conductor of heat and shields the hot glass surfaces against subsequent quenching agent, which is directed against the glass. These difficulties lead to the fact that it is extremely difficult to produce thin glass, i.e. H. Glass with a thickness of 3.17 mm (Vs inch) and less, to harden by known methods, and it is nearly impossible in thin To achieve a high degree of hardening of glass with this process.

It is also known to use the glass plates instead of by direct. Feeding a gas stream in thermal Bringing contact with cooling plates (German patent specification 1333), whereby between glass and plate metal mesh or paper inlays have also already been used.

In a known arrangement, water cooling is provided for the cooling plates (German Patent 714 303). It is also known to place glass plates in a horizontal position between two plates to cool, whereby the transfer of the glass plates to the lower cooling plate takes place via an air cushion (French patent specification 1,271,096).

The known cooling elements either easily lead to an impairment of the glass surface or are - as in the case of the interposition of paper between the mold and the glass surface (German patent specification 1333) of paper - not permanent pder when using a gas intermediate layer a reduction in the cooling effect result.

The present invention is based on these disadvantages of known heat-conducting elements to avoid. This is achieved according to the invention in that the aforementioned opposite one another Have substantially smooth contact surfaces and are made of graphite-containing, consist of thermally conductive material, so that the heat conducting elements in surface contact with the opposite glass surfaces can be brought without affecting the surface quality of the Affect the glass.

By using a graphite-containing thermally conductive material, it is possible that the Heat conducting elements with the glass surface at the

ίο named temperature without affecting the Quality of the glass surface.

The amount of heat dissipation from the glass pane through the thermally conductive material depends on a number of factors including the pressure at which the surfaces of the thermally conductive Press the material onto the surface of the glass pane. However, it is desirable that the pressure, with which the thermally conductive material is pressed onto the glass pane, kept relatively small is used to reduce the possibility of marking or embossing the surfaces of the glass pane, for example, the contacting surfaces on the glass are preferably applied with a pressure of 0.1 to 0.3 at (2 to 4 psi).

According to a preferred embodiment of the invention, there are those opposite one another Heat conducting elements made of opposing graphite plates, which conduct heat with metal blocks are arranged, the metal blocks in each case on the one facing away from the graphite plates Side have a cooling circuit system through which a cooling medium can be circulated to maintain a desired reference temperature and the rate of thermal conduction through the graphite sheets and to regulate metal blocks.

The plate made of thermally conductive material has a thickness of preferably about 1 cm in this case and the preferred material for the block is aluminum, although other metals, for example Copper, silver or steel can be used instead.

In a further embodiment of the device according to the invention, each graphite plate has on its The side closest to the flat glass to be hardened is a layer of glass fiber fabric for contact with the adjacent side Glass surface, and the surface of the fiberglass fabric which is in contact with the Flat glass is impregnated with a graphite dispersion.

The layer of glass fiber fabric according to the invention also has a thickness between 0.025 mm and 0.127 mm, and the graphite plate has a thickness between 10.2 mm and 12.7 mm, and the metal block is made of aluminum or copper

of a thickness of about 25.4 mm.

According to a further embodiment of the device according to the invention, each graphite plate also has a shallow depression in its surface closest to the glass plate to be hardened which corresponds to an area of the flat glass which is to be hardened less than the rest of the flat glass.

The glass fiber fabric, which is impregnated and coated with graphite, can be used in the cases in which such conditions prevail that the risk of cracking the glass pane exists when it is brought into contact with surfaces made of graphite alone. The heat-

conductivity of the glass fiber fabric, which is marked with Gra- In Fig. 11 the device is in position

Phit is impregnated, is close to the thermal conductivity shown, in which a pane of glass 1, which on

ability of the glass and not suspended by that of the pliers 2 is quenched.

Graphite, so that the glass fiber fabric, which is made of graphite plates facing each other

Graphite is impregnated and coated, a lower 5 existing heat-conducting elements 3 essentially have

Has thermal conductivity than the graphite plate. borrowed smooth surfaces 4, which adhere to the

Furthermore, according to the invention, each graphite plate can create surfaces of the glass pane 1. In the grain Their phit plates 3 closest to the flat glass to be hardened are resistant to oxygen Surface have at least one depression, in binder, for example a clay binder, escapes to keep in contact with the adjacent surface ίο. The surfaces 4 are in contact with of the flat glass a layer of glass fiber fabric the surfaces of the glass pane 1, whereby the pressure is, with the surface of the fiberglass fabric, between the surfaces in the order of magnitude which is 0.2 at (3 psi) with the surface of the flat glass so that actually the contact stands, with a graphite dispersion impregnated between the surfaces of the glass pane 1 is gnawed. 15 and the essentially smooth contact surfaces 4

The areas with a lower degree of hardness can only partially touch the graphite plates 3

be extensive areas to in the same one for example an actual touch of about

Get zone of vision, or they can streak or 10 to 20%. -

be extensive areas, which of others, the graphite plates 3, which have a thickness of about

elongated areas with higher hardening 20 1 cm are on solid aluminum blocks 5

degrees are drawn through, so that the combination of those with a thickness of about 2.5 cm (1 inch) attached:

two degrees of hardness form a visual zone. At the back of each aluminum block 5 is a

In order to avoid impairment of the surfaces of the cooling circuit 6 provided through which cooling heat-conducting material, the water can be conducted to the rear surfaces of the aluminum heat-conducting material in a non-oxidizing 25 miniumblocks 5 at a constant reference temperature atmosphere in thermal contact with the glass temperature, for example 50 ° C. The cooling circuit disk can be brought to the hardening process run 6 can be placed directly in the aluminum block 5 or in to influence. . . be contained in a separate chamber, which at

When the desired product is a curved the back surfaces of the aluminum blocks 5 is attached. The entire cooling system, which bent the graphite, before the hardening plates 3 according to the invention, the aluminum blocks 5 and the cooling circuit process is subjected. However, if the elbow includes 6, it is arranged so that it is on one tion of the glass pane simultaneously with the hardening organ 7 by an actuator 8, which of the glass is issued, it is determined that the a motor can be moved back and forth Pressure contact between the surfaces of the glass 35 can. . disk and the smooth contact surfaces of the Expediently, the heat-conductive during operation Material must be larger, and hung glass plate 2 from an oven (not shown) * fro there is a greater risk that the surfaces in which the glass plate to a temperature in the pane of glass to be marked or embossed .. From the order of 700 ° C is heated, ab-. For this reason, it is preferred that if one is lifted and optionally passed through a bending station, in curved tempered glass sheet is desired, which of the glass sheet a desired curvature Glass sheet is pre-bent before hardening. can be granted in a position between the

The invention is illustrated with the aid of the figures - the plates 3, the blocks 5 and the cooling circuit 6

for example explained in more detail. It shows the quenching device raised.

Fig. 1 a heated pane of glass, which is through 45 At this point in time the quenching

the device according to the invention is held, device in a retracted position, each

F i g. 2 a front view of a plate of heat but as soon as the glass is between the opposing

conductive material with a machined surface, overlying quenching devices is fixed,

In order to create a recess in the hardened glass pane, these are actuated by a motor 8

To form a zone with a lower degree of hardening, 50 organ 7 in a precisely defined position

Fig. 3 shows schematically the device in which pushed, in which the essentially smooth

the glass sheet is heated while it is on a surface 4 of the plates 3 the surfaces of the

Air cushion is worn, whereupon the heated glass-glass plate with the desired pressure in the

touch the pane by thermal contact with heat-conducting values of the order of 0.2 at (3 psi),

the material is cured, 55 after a period of about 10 seconds

F i g. 4 schematically the device in which the opposing quenching devices Glass pane vertical with the edge on a lines through the organ 7 and the motor 8 back-conveyor is balanced while it is heated and pulled, in order to remove the hardened glass by frictional contact with the heat-conducting washer 1 and to replace it with another the material is hardened to allow 60 heated sheet of glass. ; ■ F i g. 5 shows a section through another embodiment. The essentially smooth contact surfaces 4 Approximate form of a quenching front according to the invention are the plates 3 made of thermally conductive material direction and be at a temperature of the order of magnitude

F i g. 6 shows a section through part of a pre of 300 ° C when the surfaces are heated direction to achieve different degrees of hardness 65 glass pane 2 with a thickness of 0.5 mm (Vs inch)

in different parts of the glass pane. to be brought. This temperature is determined by the

In the figures, the same or similar parts are surfaces 4 with continuous work of the pre

provided with the same reference numerals. direction of course maintained, but if the

5 6

Device is started, it is desirable to have a base height of the surface 14 and a

that the contact surfaces 4 of the graphite plates 3 different height in an approximately circular area

be heated before a hardening process of glass 15 has. The height of the area 15 is around

discs takes place. In this way, a split 0.05 mm ( ² / 1,000 inch) into the substantially smooth one can be made

tern of panes of glass during the initial state 5 base surface 14 retracted, and the retracted

of the procedure can be essentially avoided. Surface 15 also represents an essentially

The temperature of the pane of glass with its smooth surface.

tion with the substantially smooth surfaces 4 The opposite graphite plate 13 has a

the graphite plate 3 is generally in the size-corresponding recessed area 15, so that,

Order of 680 ° C. OK when the two plates 13 are in thermal contact

For different thicknesses of glass panes, the heated glass dies with opposing surfaces The device and the working conditions are brought to a disk, the areas 15 at one changes to different temperatures on the upper part of the heated glass sheet facing each other to achieve the thermally conductive material. superior.

For example, for glass with a thickness of 15, the graphite plates 13 press on the surfaces of 6.3 mm ( ¹ Å inch) the surfaces 4 on one of the heated glass sheets 1 with pressures in the temperature of the order of 200 ° C., and order of magnitude of 0.2 at (3 psi), and this represents the pressure for glass with a thickness of 3.2 mm (Vs inch) which is exerted between the surface 14 and the surfaces 4 at an even lower temperature The surface of the heated glass pane is maintained, the temperature is kept between about 50 and 100 ° C. There is 20 on the retraction in the area 15, which in turn is preferred, however, that the surfaces 4 also maintain a substantially smooth surface at temperatures higher than those mentioned, the pressure between this area 15 and are, both when the glass sheet is bent as of the heated glass pane and there can also be no pressure at all in this area due to contact with the surfaces 4, where hardening takes place. 25 The heat conduction from the glass through the area 15

It is found that the graphite plate 3 emerges due to the proximity of one to the other . must be cut so that they do not interfere with the others, even if there is no pressure contact. Pliers 2 collide, which is the glass pane 1. The amount of heat conduction from the glass stretcher, However, it has been found that a slice to the area 15 is less than that good hardening of the glass pane when using the amount of heat conduction from the rest of the glass pane described and in F i g. 1 shown device in the area 14 of the graphite plate 13, and in the tion is achieved. Glass compared to area 15 achieved hardening

The essentially smooth contact surfaces 4 degrees is significantly less than that in the rest, the graphite plates 3 can each have a corresponding degree of hardness achieved in contact with the area 14 glass end curvature, for example the curvature 35 disc,
An arc of a circle with a radius of 2.54 m. Advantageously, the process will have in a nitrogen (100 inches), and if this curved atmosphere, which is a non-oxy-surface4 in contact with the planar glazing atmosphere, so that the top pane 1 is brought, the glass pane in surfaces of the graphite plates 3 and 13 is again bent into a similar curved shape as the surfaces 4 40 carried out the method not adversely at the same time in which the graphite is done.

plates 3 harden the glass. As already mentioned, in FIG. 3 is schematically a device with the curved surfaces 4 shown during operation on a heating zone 21, in which a glass temperatures held, which are much higher disc is heated while the glass plate 22 is on than the temperatures at which even upper 45 a gas cushion is supported, which by the surfaces 4 are held. . Passing through to a temperature in the size

In another mode of operation of the one shown in FIG. 1 order of 700 ° C heated air through a porous

The device provided is the actuating device 8 sen brick or a clay molding 23 is produced,

arranged so that the entire cooling system is in calm- The air which the the glass sheet 22 during

tion with the heated glass sheet 1 advanced 50 of the heating-supporting gas cushion forms is through

and on the surfaces of the glass sheet, pressing a conical inlet tube 24 through a plurality of

of about 0.2 at (3 psi) is applied, and these heating elements 25 are introduced which heat the air

Pressure is maintained for about 5 seconds. respectively.

At the end of the 5 second period, the porous clay molding 23 itself will act on a

Actuating device 8 with the total cooling 55 temperature of the order of 650 ° C

system on the surfaces of the glass pane 1 under heat, and the porous molding (by radiation)

an elevated pressure of 38 at (15 psi) and that forming the gas cushion or pad

this increased pressure will deliver heat to the hot air (by conduction) over another 5 seconds

maintained, after which the whole cooling system is a lower surface of the glass pane 22.

finally the graphite plates 3, the aluminum 60 ments 26 within a cover 27 provide

block 5 and the cooling circuit 6 by means of the heat on the surface of the glass pane 22.

actuating device 8 through the organ 7 back- The glass pane 22 is in the heating zone 21 through

is drawn: an inlet 28 is given and is in the heating zone

In Fig. 2, the front view of another is only through one above the porous ceramic-graphite plate 13 shown, which in the same way 65 plate 23 held existing gas cushion. The porous on an aluminum block 5 with a cooling circuit clay or ceramic plate 23 is at an angle barrel 6 is attached. The surface 14 of the graphite inclined to the horizontal, the inclination However, plate 13 is a thermally conductive surface, the plate 23, viewed according to FIG. 3, from the left

7 8

to the right is about half a degree. Which moves, of which for the sake of clarity of representation Movement of the glass sheet 22 through the heating zone only lengthways the boxes on the remote side of the glass the inclination of the ceramic plate downward disk in F i g. 4 are shown. The one another under the action of gravity is through an opposing blow box 48 are so angeord-stop 29 controlled which in the path of the glass 5 net, that it gas flows against the opposite pane 22 through a side wall of the cover direct the surfaces of the glass pane in order to is brought over the heating zone 21 in order to avoid pressure and contact with the surfaces the fact that the glass sheet 22 leaves the heating zone 21 in front of the glass sheet and gas layers, before it's properly heated. touch with the surfaces of the glass pane

When the glass sheet 22 is sufficiently heated to form standing gas cushions. The glass panel will

d. that is, to a temperature of about 680 ° C., is therefore in a vertical position on the support member 46

the stop 29 is withdrawn, and the heated one is balanced while it is between the opposite

Glass plate 2 can now be conveyed along the incline of the lying gas box 48.

Gas cushion over the porous ceramic plate 23 after during the passage of the glass plate 47

move down and through an outlet 30 from the 15 between the opposite blow boxes 48 is

Exit heating zone in order to heat the glass through electrical heating elements 49 over a porous graphite

plate or a graphite brick 31 through one of the, which is behind the narrow gas boxes 48

Underside of the porous brick 31 are arranged by a tube 32 so that they heat through the gap

supplied air cushion to be held. The first between the gas lockers on the pane of glass

Heated sheet of glass will similarly conduct on the 20 as it progresses through the heating zone.

Air cushions over the porous brick or shaped piece.Furthermore, the pressurized gas

31 held by a stop 33. pillow showing the glass panel in the vertical

Immediately when the heated glass pane is above the porous position in the heating zone between the gas boxes 48

sen plate 31 comes to rest, this is done by balancing, by gas flows, for example air,

Glass fed to tube 32 is removed by means of valve 34 at a temperature in the range from 600 to 800.degree

switches so that the gas cushion collapses and is held and so help to keep the glass on a

the heated glass sheet in contact with the temperature above its deformation point

Graphite plate 31 falls down. At the same time one will bring.

second graphite plate 35 down on the top while the glass sheet along the conveyor in brought surface of the glass pane, so that both upper 30 is moved forward in the direction of arrow 50, erflächen of the glass pane 22 of graphite plates, it reaches a position in which the glass stirs and the pane of glass is no longer between the opposing panes Heat dissipation through the graphite plates gas boxes 48, but between opposite frightens. porous plates 51 is located.

The graphite plate 35 is on an aluminum 35 through each of the porous ceramic plates 51 is

block 36 attached, which on its back an air introduced to air cushions on the glass pane

Circuit 37, the same being maintained in each direction while this is in the room

sees the graphite plate 3, the aluminum block 5 between the opposing porous plates

and the water circuit 6 according to FIG. 1 similar to 51 occurs.

are. The whole quenching system with the graphite 40 Each of the porous plates 51 is on an aluminum plate 35, the aluminum block 36 and the water minium block 52 attached to the other side thereof circuit 37 is attached to an organ 38 by a water circuit 53. The air will Actuating device, such as a motor 39, moves. of the porous graphite plate 51 by piping

Controlling the amount of heat dissipation 54 supplied by the water circuit 53

from the lower surface of the glass pane through the porous 45 and the aluminum block 52 are passed.

Graphite plate 31 is also by the presence. Accordingly, the glass sheet 47 is through

of the aluminum block 40 and the water circuit, the gases passing through the porous plates, respectively

41 controlled behind the graphite plate 31. However, to enter 51, held in a vertical position while

To supply gas to the porous graphite plate 31, the glass sheet is in the space between the two

Pipe penetrations 42 through the water circuit 5 ° porous plates 51 enters.

41 and the aluminum block 40 are provided to air when the glass sheet 47 is completely between

from the pipe 32 to the porous graphite plate 31. the two porous plates 51 is located, the front

It is noted that the gas cushion is above the upward movement of the glass sheet on the conveyor porous graphite plate 31 is not stopped so completely, so that the glass sheet 47 to rest The gas cushion is like the one that comes over the porous ceramic, and at the same time the air supply mikplatte 23, it suffices, however, to enable the porous plates 51 switched off and the that the glass sheet 22 is advanced over the graphite plate 31, two of the porous plates 51, the aluminum without any upper blocks 52 and the water circuit 53 existing surface damage suffers before the pillow is moved forward over assemblies against each other, the graphite plate 31 collapses. 60 so that the opposing surfaces 55 of the

In Fig. 4, a conveyor for a sheet of glass porous plates 51 is in contact with the surfaces or glass plate, which a number of the glass pane are brought to the glass pane Has rollers 45 and an organ 46, which is used to harden according to the method according to the invention, Carrying a glass plate 47 is suitable, whereby only the amount of heat dissipation from the Oberlich the lower edge of the glass sheet in contact 65 surfaces of the glass sheet according to the thickness of each with the fixed support member 46 is. porous plate 51, each aluminum block 52 as well

The glass pane 47 is maintained by the conveyor between the water circuit 53

see opposite blow boxes 48 forward temperature is controlled.

In Fig. 5 shows a section through a device in which the surface which contacts the surface of the glass pane consists of a surface 56 of a layer 57 of glass fiber fabric which is impregnated and covered with graphite. Layer 57 is on the order of 0.08 mm ( ³ / 1,000 inch) thick and is thermally conductive to a graphite plate 58 approximately 10.2 mm (0.4 inch) thick, which in turn is thermally conductive to an aluminum block 59 is attached to a thickness of about 2.54 cm (1 inch).

At the back of the aluminum block 59, a water circuit 60 is arranged, which is related to the 1, 3 and 4 described is the same. ,

In Fig. Figure 6 shows a section through part of a quenching device so modified is that they have areas with relatively higher and lower in the tempered glass pane Degree of hardening generated. In Fig. 6 shows an aluminum block 61 with a water circuit 62, to maintain a reference temperature at the rear of the block 61, and the other or The front surface of the aluminum block 61 is attached to a graphite plate 63 in a thermally conductive manner. ;

The smoothly machined surface 64 of the graphite plate 63 is cut to a depth of about 0.08 mm ( ³ / 100o inch) in portions of the surface which correspond to the areas of the glass sheet in which a lower degree of hardening is to be produced, and these cut out portions in the surface 64 are filled with glass fiber fabric 65 which is impregnated with graphite, so that the glass fiber fabric 65 is a surface which is a continuation of the surface 64 of the graphite plate, and the glass pane to be hardened is presented with a substantially smooth surface.

Accordingly, there are areas with a higher degree of hardness in the parts of the glass sheet which are contacted by the surface 64 of graphite, and areas with a lower degree of hardening are produced in the parts of the glass pane, which are hardened by contact with the soaked glass fiber fabric 65.

Claims (6)

Claims: 45 1. Device for hardening flat glass, with opposing heat conducting elements and means for bringing them into conductive contact with the opposing ones Areas of the flat glass at a temperature above the deformation point to bring, and with a cooling device connected to the heat conducting elements in order to connect to the glass-remote sides of the heat conducting elements a desired reference temperature to control the Maintain the heat conduction speed from the flat glass through the heat conducting elements, characterized in that said opposing heat conducting elements (3; 13; 31, 35; 51, 55; 57, 58; 63, 65) essentially smooth contact surfaces (4; 14; 56; 64) and made of graphite-containing, thermally conductive material, so that the Heat conducting elements brought into surface contact with the opposing glass surfaces (1) without affecting the surface quality of the glass. 2. Apparatus according to claim 1, characterized in that the opposite Heat conducting elements (3; 13; 31, 35; 51, 55; 57, 58; 63, 65) from opposite Graphite plates (3; 13; 31, 35; 51, 55; 63) are made, which are in thermal conduction with metal blocks (5; 36, 40; 52; 59; 61) are arranged, the metal blocks each on the of the Graphite plates have a cooling circuit system (6; 37, 41; 53; 60; 62) on the opposite side, through which a cooling medium can be circulated to a desired reference temperature and maintain the conduction rate through the graphite plates and metal blocks to regulate. 3. Device according to claim 2, characterized in that that each graphite plate (58) is closest to the flat glass (1) to be hardened Side has a layer (57) of glass fiber fabric for contact with the adjacent glass surface and the surface (56) of the fiberglass fabric which is in contact with the flat glass, is impregnated with a graphite dispersion. 4. Apparatus according to claim 3, characterized in that the layer (57) made of glass fiber fabric has a thickness between 0.025 mm and 0.127 mm and that the graphite plate (58) has a thickness between 10.2 mm and 12.7 mm and also the metal block (59) made of aluminum or copper about 25.4 mm thick. 5. Apparatus according to claim 2, characterized in that each graphite plate (13) in their surface (14) closest to the glass plate (1) to be hardened has a shallow depression (15), which corresponds to a region of the flat glass which is less hardened should than the rest of the flat glass. 6. Apparatus according to claim 2, characterized in that each graphite plate (63) in its the surface (64) closest to the flat glass (1) to be hardened has at least one depression, in which a layer (65) for contact with the adjacent surface of the flat glass made of fiberglass fabric, the surface of the fiberglass fabric that connects to the surface of the flat glass is in contact, is impregnated with a graphite dispersion. 1 sheet of drawings