Device for reducing end deflection of a glass sheet

专利摘要:
The invention relates to a device for reducing the end deflection of a glass sheet (G) in a glass curing process, wherein the device comprises a roller roll (5) arranged on a roller track for moving glass sheets after the glass curing oven (1), the roller roller (5) being arranged in the roller track between two drive rollers (4), which roller (5) comprises a plurality of separately freely rotating rollers (10), which rollers (10) support the glass plate (G) as it moves from the curing oven (1) to the curing cooling device (2). The invention also relates to a method for reducing the end deflection of a glass sheet (G) in a glass curing process, and to a system comprising the device according to the invention.
公开号:FI20205292A1
申请号:FI20205292
申请日:2020-03-24
公开日:2021-04-30
发明作者:Pekka Lyytikäinen；Pete Harjunen
申请人:Glaston Finland Oy；
IPC主号:

专利说明:

The invention relates to a method for thermally reinforcing or tempering glass sheets, in which the glass sheet is heated to a tempering temperature and the actual cooling of the glass sheets is carried out. a roller consisting of freely rotating rollers to be mounted in the oven.
—Glass plate tempering furnaces in which the glass plates move in one direction or back and forth on rotating ceramic rollers and from which they pass at tempering temperature along a roller path to a tempering cooling unit at the rear of the furnace where tempering is performed by air jets and is commonly used. A furnace with a roller track is referred to in the art as a roller oven, for example. The typical temperature of the oven is 700 ° C and the temperature of the air typically used for cooling is about the same as the temperature of the air outside or in the factory hall. Cooling air is supplied by a fan or compressor. In furnaces and tempering cooling units based on air support technology, the glass sheet floats supported by a thin air mattress and only touches the rollers or other conveying members of the conveyor track at one of its side edges. An oven based on air support technology is referred to in the art as, for example, an air support oven. The typical tempering temperature of a 4 mm thick glass sheet, i.e. the temperature at which the glass passes from the furnace to the tempering cooler unit, is 640 ° C. The tempering temperature of the glass can be slightly reduced as the thickness of the glass increases. Increasing the tempering temperature allows the glass to be tempered thinner and thinner and reduces the cooling power required for tempering cooling. On the other hand, a mere increase in the tempering temperature, for example from N 640 ° C to 670 ° C, brings a much higher degree of reinforcement, i.e. 3 tempering, to the 4 mm thick glass, i.e. the compressive stress of the glass surface increases. For example, with thin 2 mm N thick glass, the tempering temperature must be raised to at least 660 ° C for tempering E to be successful. The reduction in the thickness of the glass and the increase in the tempering temperature both add to the end deflection problem which the invention solves.
2 The glass entering the tempering process has excellent straightness and optical properties. In it, the compressive stress of the glass surface is typically 1-4 MPa. In the tempering process, a sufficient increase in strength is sought for the glass sheet while minimizing its straightness and optical properties. In addition to strength, another desired property of tempered glass is its safety in the event of breakage. Untempered glass breaks into large pieces that can cut. Tempered glass breaks into almost harmless crumbs.
- The compressive stress (degree of hardening) produced on the surface of the glass during tempering depends on the temperature profile in the thickness direction of the glass as the glass cools through the glass-specific transition temperature zone (approximately 600-500 * C). Thinner glass requires more cooling power to achieve the same temperature difference. For example, for a 4 mm thick glass sheet, a surface compression of about 100 MPa is desired in tempering, in which case there is a tensile stress of about 46 MPa in the middle of the glass thickness. Such a glass sheet breaks into crumbs that meet the requirements of safety glass standards. In so-called FRG (fire resistant glass) tempering, a clearly higher surface compressive stress (at least 150 MPa) is desired. FRG hardening is successful when the cooling capacity of the air jets in the hardening cooling unit is clearly increased in proportion to the hardening. The so-called.
—The aim is not to achieve a safe method of breaking for thermally toughened glass, nor to have as high a strength (surface compression of about 50 MPa as is sufficient) as for toughened glass. Thermal reinforcement is successful when the cooling capacity of the air jets in the tempering cooling unit is clearly reduced relative to the tempering. The present invention solves the end deflection problem in glass tempering, which also includes thermal reinforcement. The above-mentioned tempering temperatures are also suitable as examples for thermal reinforcement, i.e. the tempering temperature also means thermal reinforcement temperature. The end deflection problem is largely independent of whether a surface compressive stress of 50, 100 MPa or even higher is desired if the tempering temperature remains the same.
The end deflection is generally referred to as the downwardly bent shape of the downwardly directed ends of the glass.
N g The formation of the end deflection begins when the end of the glass begins to flow downwards during heating. The end creeps because the glass is heated in a furnace to a temperature above 500 ° C, whereby the mechanical properties of the glass begin to change relatively sharply. Glass a begins to change from elastic to plastic at the same time. The deformation of the glass reverts & 30 - as the plasticity increases less and less. Bending and creeping of the end of the glass would not occur if the glass were evenly supported in the oven. However, in a roll furnace, there are glass support points (lines N) only at distances between the roll divisions (typically 7-14 cm). In an air support furnace, an overpressure (relative to the pressure in the furnace air) air mattress supports the edges of the glass less than the rest of the glass area, because the static overpressure supporting the glass in the air mattress is lower at the edges of the glass. The glass bent at the ends of the furnace does not automatically straighten under tempering cooling, which solidifies the glass to its final elastic shape in a few seconds. The end deflection typically begins at about 70-200 mm - from the ends of the glass, e.g. depending on the thickness of the glass and the type of tempering machine. Figure 1 illustrates a method for measuring the end deflection of glass according to EN12150-1. In it, the upper surface of the glass is the opposite surface with respect to the direction of the end deflection. The glass is placed on the measuring plane so that its end exceeds the plane by 50 mm. A straight ruler 300-400 mm long is placed on top of the glass so that the dial gauge at one end of the ruler is right at the end of the glass to be measured. The dial gauge reading is the end deflection of the glass. Em. according to the standard, for example, for 4 mm thick glass, the permissible end deflection is 0.4 mm. In practice, the requirements of tempered glass producers for end deflection are somewhat tighter than standard. The ever-improving quality values of glass are for the manufacturer of the tempering machine, and still for the producer of tempered glass, - a competitive advantage.
The end deflection problem arises in part during the transition from the tempering furnace to the tempering cooler, when the glass is at its hottest. During the transfer, the glass rests on the rollers moving it, which inevitably leave a gap of about 10 cm. It is not possible to bring the rollers closer together because the bearings at their ends and the gear and other parts required for roller operation are clearly larger in size than the diameter of the roller. On the other hand, the measuring scanner of a temperature scanner, for example, which measures the temperature of the glass, also requires its own space, which limits the short distance between the end of the furnace and the beginning of the tempering cooler. There should also be a distance between the start of the hot furnace and the tempering cooler for reasons related to the durability and energy consumption of the materials.
g In EN20175608, the end deflection problem in question is solved by S, at the beginning of tempering cooling, compressed air is blown onto the upper = front surface of the glass plate front and rear to reduce the front and rear end deflection α of the glass plate. The solution requires relatively complex blowing equipment and & 30 - accurate information on the location of the ends of the moving glass sheet in relation to the blowing equipment.
The object of the invention is a method and a device with which tempered glass sheets can be made straighter at their front and rear ends. The object of the invention is therefore to improve the quality of the glass by reducing it (e.g. measured according to standard EN12150-1)
end tendency. The object of the invention is to reduce the end deflection, in particular in glasses requiring a tempering temperature above 6509C and / or less than 3.5 mm thick. This object is achieved by a method of reducing the end deflection of a glass sheet in a glass tempering process in which the glass sheet (G) is heated to tempering temperature and - actual tempering cooling is performed by blowing cooling air at -a pulling roller, the support of which prevents the end deflection of the glass sheet, and a device for reducing the end deflection of the glass sheet in a glass tempering process, the apparatus comprising a roller roll arranged on a glass moving roll track after the glass tempering furnace, each roll roll comprises a plurality of separately freely rotating rollers which support the glass sheet as it moves from the tempering furnace to the tempering cooling device, thus preventing the end deflection of the glass sheet. The invention also relates to a system comprising a tempering furnace, a tempering - cooling unit and a device to be mounted therebetween to reduce the end deflection of a glass sheet. Preferred embodiments of the invention are set out in the dependent claims. In the requirements, tempering generally means significant reinforcement of glass based on heat treatment. Figure 1 shows a method of measuring the end deflection of glass in the EN12150-1 standard. Figure 2 shows a system according to the invention comprising an air support furnace, a tempering cooling unit and a device to be installed between them - Fig. 4 shows a device according to the invention between two driving rollers> 30 - Fig. 5 shows a device according to the invention
S NN The system according to the invention comprises a tempering furnace 1, which may be either a roll furnace or an air support furnace which heats the glass to a tempering temperature of about 620-700 ° C,
and a tempering cooling unit 2, which is generally roll-supported and a device mounted therebetween to reduce end deflection. The tempering furnace 1 and the tempering cooling unit 2 are sequentially in the direction of travel 5 - (direction x) of the glass sheet G in said order according to Fig. 2. The horizontal rollers 4 of the furnace (shown in Fig. 3) or the air support table 3 with their conveying means form a conveyor track of a glass sheet. The conveyor track generally has at least two drive rollers between the end of the furnace and the blow housing 6 of the first quench cooling unit. The heated glass sheet G is conveyed in the furnace 1 continuously at a constant speed in the same direction or back and forth for the heating time. The glass sheet G heated to the tempering temperature is transferred from the furnace at a transfer rate of TV to the tempering cooling unit 2. Typically, the transfer rate of the TV is 200 to 1000 mm / s depending on the thickness of the glass. When the end of the glass sheet comes out of the oven, it rests on a device for reducing the end deflection, i.e. the roller roll 5, this leads to a reduction in the end deflection. Between the tempering furnace 1 and the cooling unit 2 there is preferably a temperature scanner 9 for monitoring the temperature of the glass plate G. In the cooling unit, the glass sheet is cooled by blowing cold air from the blow housings 6 through the blow stockings 14 onto the surface of the glass sheet. The flow barriers 7 choke the air outlet path that hit the upper surface of the glass as the roller chokes the air that hit the lower surface so that the glass stays on the rollers.
The device for reducing end deflection comprises a so-called free-rotating roller 10. a roll roll 5, which roll supports the glass sheet G as it moves from the tempering furnace 1 to the tempering cooling device 2, thereby preventing the end deflection of the glass sheet G. Unlike the traction rollers 4, the roller roller 5 has no traction, i.e. it is a non-traction roller. The roller roll 5 comprises a row of adjacent freely rotating rollers 10, each of which may have its own bearing or a bearing-like structure implementing a free freewheel. For example, instead of the actual bearing, the shaft passing through the roller can rest at its ends on e.g. U-shaped N supports, where it rotates from its shaft, i.e. the end of the shaft lightly rubs the bottom of the U-shape. I In this way the rollers rotate freely independently of each other. The rollers 10 are light and> 30 - a roller-specific bearing or other arrangement ensures easy rotation of the roller 10. When the glass sheet 3 hits the roller 10, it rotates and supports the glass sheet, i.e. the end of the glass rests on it, and the end deflection decreases. Other deformations depending on the support of the hot flowing glass sheet, such as the roll wave, may also be reduced.
In systems comprising a tempering furnace 1 and a tempering cooling unit 2, the division of the drive rollers 4 cannot be made short enough to prevent end deflection, because the bearings 12 at the ends of the rollers 4 and the gears of the roller drives 13 are space consuming.
The roller drives 13 include a sprocket at the end of the roller, a chain and a motor, which together are large.
In many cases, a temperature scanner 9 is also installed in the systems between the furnace 1 and the cooling unit 2 for monitoring the process.
The scanner 9 provides information that can be used to control both the hardening process and the cooling process.
The scanner also required some space between the oven 1 and the cooling unit 2.
The third reason why space is required between the furnace 1 and the cooling unit 2 is to prevent hardening cooling air from entering the furnace.
If the furnace 1 and the tempering cooling unit 2 are too close to each other, the quenching cooling air enters the furnace, thus interfering with the quenching process.
The roller supports the glass from its point.
The distance between the rollers is the distance between the centers of the rollers in the direction of movement x of the glass, which is equal to the distance between the centers of the axes of rotation of the rollers in the same direction x.
According to a preferred embodiment, the freely rotating roller roll 5 reduces the roll gap by half.
Preferably from about 10 cm to about 5 cm, i.e. from 6 to 14 cm to 3 to 7 cm.
The roller roll 5 is located in the roll track on the section between the tempering furnace and the tempering cooling in the first blow box.
Figure 3 shows an embodiment of a system according to the invention, in which, in addition to the last or post-driving roller 4 of the tempering furnace 1, a driving upper roller 8, which together with the driving roller forms as if a roller nip.
The upper roll 8 does not necessarily have to hit the glass G, and at least it must not significantly press the glass onto the lower roll 4. The upper roll 8 o 25 - is arranged directly above the driving roller 4 outside the tempering furnace, preferably so that the axes of both rolls are vertically it is in the same line.
Due to the combined action of the upper roll 8 and the roll roll 5, the end deflection of the glass end N is further reduced and the upper roll 8 also effectively prevents the cooling air from entering the furnace.
Preferably, the upper roll 8 is at least partially covered with a heat-insulating nonwoven fabric or a nonwoven strip, such as a kevlar strip.
S Fig. 4 shows a top view of the part of the roller track between the tempering furnace and the tempering cooler.
The figure shows only a part of the length of the rollers and blow boxes.
A roller roller 5 mounted between the drive roller 4 after the tempering furnace and the first drive roller 4 of the tempering cooling unit 4. As shown in Fig. 4, the bearings 12 of the drive rollers 4 are bulky and thus cannot be brought close enough to each other achieve the necessary reduction in end deflection. Figure 4 also shows blower housings 6 with blow holes 14, from which the air blowing hitting the surface of the glass cools very rapidly under the glass at temperatures favorable for the growth of the end deflection. Fig. 5 shows a device according to the invention for reducing the end deflection of a glass sheet, i.e. in other words a freely rotating, i.e. non-traction, roller roller 5. The roller roller 5 comprises a plurality of spaced apart rollers 10 arranged separately to rotate freely. . Preferably, the distance S between the sides of the rollers is 1 to 50 mm and the width W of one roll is 5 to 50 mm. Preferably, the outer diameter of the roll is 10 to 40 mm. The rollers have a metal frame, preferably a light metal frame, and their surface is - provided with a heat-resistant, insulating and non-scratch glass fiber braid, i.e. a non-woven fabric, for example a kevlar strip or sock. Preferably the metal is aluminum. The nonwoven fabric is wrapped around the disc so as to substantially prevent contact of the metal body of the roll with the glass sheet. The individual rollers 10 are attached to the elongate body 11. The length of the body 11 is compatible with the width of the oven so that the rollers 10 attached thereto cover the width of the oven so that the glass is supported over its entire width regardless of the width of the glass sheet. According to a preferred embodiment, the distance S between the sides S of the two individual rollers 10 is about half the width W of the roll 10 to the width o 25 W of the three rollers 10.
S Roll 10 is preferably cylindrical in shape. The shaft of the roller is integral with the axis of the cylinder. In this case, the surface of the cylinder is provided with a nonwoven fabric, with the exception of the end surfaces. * 30 3 The advantage of the roll roll 5 over a single roll is the lighter rotation N of a single roll. A single roll on its own rotates substantially lighter relative to the longer N roll. Since the function of the non-pulling roll is to transport the glass by supporting it, it is essential that the roll rotates as smoothly as possible so that the front end of the moving glass does not collide with it and does not slow down the movement of the glass. Slowing or stopping or jerking the movement of the glass would adversely affect the outcome of the tempering process, such as the quality of the glass. Another advantage of the roller is its good adjustability due to the individual rollers. It is possible to adjust each roller individually in the vertical direction (y direction), ie the height position of the roll's point is set to be adjusted for each roller. Preferably, the vertical adjustment of the rollers is at least 5 mm. The adjustment allows you to adjust the support base of the roller. The adjustment is necessary because there are differences in the diameters of the rollers due to the tolerances of its parts and the body 11 is not completely straight. The adjustment allows the support line to be straightened despite the deviation of the roll roller dimensions. When the glass comes out of the tempering furnace, it may typically be slightly bent in the width direction (horizontal direction transverse to the movement of the glass, i.e. direction z), and not completely straight. Especially in the case of the air support furnace, the glass plate is shaped at the end after the tempering heating so that the angles are lower than the central area. In this case, the rollers can be adjusted - higher in the middle area than on the sides and thus guarantee the support of the rollers on the glass plate over the entire width of the glass plate. The position of the rollers can also be adjusted individually in the z-direction within a distance S of about a distance, i.e. in other words the position of the rollers can be adjusted for each movement of the glass - in the transverse horizontal direction. With an adjustment in this direction, for example, the roller can be moved to support exactly the side edge of the glass. Preferably, the adjustment margin of the rollers in the z-direction is the distance between the sides of the rollers minus 10 mm. The invention described above is not limited to the embodiment shown, but can be modified in many different ways within the scope of the claims. OF O OF
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权利要求:
Claims (13)
[1]
An apparatus for reducing the end deflection of a glass sheet in a glass tempering process, the apparatus comprising a roller roll arranged on a glass moving roller track after a glass tempering furnace, characterized in that the roller roller is in a roller track between two driving rollers. as it moves from the tempering furnace to the tempering chiller.
[2]
Device according to Claim 1, characterized in that the freely rotating roller roller 5 reduces the roller gap by half.
[3]
Device according to Claim 2, characterized in that the freely rotating roller roll 5 reduces the roll gap from 6 to 14 cm to 3 to 7 cm.
[4]
Device according to one of Claims 1 to 3, characterized in that the height position of the legal point of the rollers is set to be adjustable for each roll.
[5]
Device according to one of Claims 1 to 4, characterized in that the position of the rollers can be adjusted on a roll-by-roll basis for the movement of the glass in the transverse horizontal direction.
[6]
Device according to one of Claims 1 to 5, characterized in that the roller is made of light metal.
[7]
Device according to one of Claims 1 to 6, characterized in that in the roll, its contact surface with glass is at least partially coated with a fibrous braid.
S
N se
[8]
Device according to one of Claims 1 to 7, characterized in that the distance S between the sides of the rollers of the roll roll s is 1 to 50 mm and the width W of one roll is 5 to 50 mm. =
N 2
[9]
Device according to one of Claims 1 to 8, characterized in that the
The distance S between the LO S is 0.5 to 3 times the width W of the roll.
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OF
[10]
Device according to one of Claims 1 to 9, characterized in that the outer diameter of the roll is 10 to 40 mm.
[11]
11. A system for reducing the end deflection of a glass sheet in a glass tempering process, the system comprising a glass tempering furnace and a tempering cooling device and a post-tempering glass moving roller track, characterized in that the roller track has a roller which support the glass sheet as it moves from the tempering furnace to the tempering cooling device.
[12]
The system of claim 11, further comprising, in addition to the last drive roll of the tempering furnace, an upper roll which, together with the drive roll, forms a nip roll.
[13]
A method for reducing the end deflection of a glass sheet in a glass tempering process, wherein the glass sheet (G) is heated to a tempering temperature and the actual tempering cooling is performed by blowing cooling air on both surfaces of the glass sheet. rollers, which - the support of the roll prevents the end deflection of the glass sheet.
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同族专利:

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CN113501662A|2021-10-15|

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FI20205292A|FI129004B|2020-03-24|2020-03-24|Device for reducing end deflection of a glass sheet|FI20205292A| FI129004B|2020-03-24|2020-03-24|Device for reducing end deflection of a glass sheet|

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CN202110143282.0A| CN113501662A|2020-03-24|2021-02-02|Device for reducing end edge distortion of glass sheets|