WO2012169429A1 - Glass forming device, and glass forming method - Google Patents

Abstract

Provided are a glass forming device and a glass forming method whereby a plate glass in which the quality and size, such as plate width and plate thickness, are even and in which the occurrence of warping and cording are prevented is formed by subjecting a molten glass, especially a molten glass having low viscosity, to a roll out process. A glass forming device used for forming a molten glass, the glass forming device being characterized by having: a pair of forming rolls disposed such that the rotating axes are parallel to one another at a predetermined distance; a pair of molten glass blocking members which is disposed at an interval in the axial direction of the forming rolls in an upper-side space part formed by means of the forming surfaces of the pair of forming rolls and which form a reservoir for the molten glass in the upper-side space part; a temperature adjustment means disposed at least in the interiors of the pair of forming rolls; and a control means for controlling the temperature adjustment means so as to control the surface temperatures of the pair of forming rolls.

Description

Glass forming apparatus and glass forming method

The present invention relates to a glass forming apparatus and a glass forming method.

The casting method is a method for forming a glass having a steep temperature-viscosity relationship, such as fluorophosphate glass or phosphate glass, that is, a molten glass having a very low viscosity from a molten state to just before solidification into a plate shape. Conventionally, a melted glass substrate is poured onto a movable table such as a plate-like fixed table or a conveyor or a mold, and extruded into a slow cooling zone while the glass is solidified by cooling with the table or mold. In this method, a rolling roll is widely used for the purpose of cooling and film thickness adjustment when extruding.

However, in the above casting method, it is difficult to control the molding conditions such as the amount of molten glass supplied, the molding temperature, and the time, and the molding is performed while the glass substrate surface is exposed to the atmosphere over a wide range. In the case of a glass composition composed of high components, the active component volatilizes from the surface of the glass substrate during the molding, resulting in non-uniform components, and the occurrence of striae and distortion due to these has been a problem.

Therefore, technology development has been carried out in order to solve these problems. For example, Patent Document 1 describes a technology for controlling the molding temperature of molten glass by the surface temperature of a rolling roll. Patent Document 2 discloses a technique for controlling the speed of a conveyor in accordance with a change in the amount of molten glass supplied. Patent Document 3 discloses a technique for controlling a supplied amount of molten glass. Techniques relating to temperature control of a mold to which molten glass is supplied are described. However, none of these methods is capable of sufficiently suppressing the occurrence of the striae and distortion.

Furthermore, in the above casting method, since the plate thickness is uniquely determined by the surface tension, it is difficult to reduce the thickness, and even if attempts are made to reduce the thickness using a member such as a squeegee or a rolling roll, Further, since the thickness is returned, it is difficult to form a thin plate having a uniform thickness. Therefore, it is necessary to remove the non-uniform thickness portion and the defective portion of the obtained plate glass by mechanical polishing, and improvement in terms of product yield is also required.

On the other hand, as one of the methods for forming a high-viscosity molten glass made of soda lime glass or the like into a plate with good productivity, conventionally, the molten glass is supplied between two rolls arranged in close proximity to each other, A rollout method (see, for example, Patent Document 5, Patent Document 6, and Patent Document 7) in which a glass substrate flows down from a slit-shaped outlet between rolls is applied.

It is conceivable to use this rollout method in order to improve the above-mentioned problem in the plate-like molding of the low-viscosity molten glass. Even if it is applied, uniform supply to the roll of molten glass and proper temperature control of the roll cannot be performed sufficiently, and the obtained plate glass is uneven in size, quality, etc. Yes, not.

JP 2003-171127 A JP 2003-192361 A Japanese Patent Laid-Open No. 2006-143569 JP 2007-269500 A JP 2000-203853 A JP-A-10-297828 Japanese Patent Laid-Open No. 11-139837

The present invention has been made in order to solve the above-mentioned problems. Molten glass, in particular, low-viscosity molten glass is suppressed by the roll-out method, and the occurrence of striae and distortion is suppressed, and the plate width, thickness, etc. An object of the present invention is to provide a glass forming apparatus and a glass forming method that can be formed into a plate glass having a uniform size and quality.

The glass forming apparatus of the present invention is a glass forming apparatus used for forming molten glass, and a pair of forming rolls whose rotation axes are arranged in parallel with each other at a predetermined interval, and the pair of forming rolls A pair of molten glass damming members which are disposed in the upper space defined by the molding surface at an interval in the axial direction of the molding roll and form the molten glass reservoir in the upper space. And a temperature adjusting means arranged at least inside the pair of forming rolls, and a control means for controlling the temperature adjusting means so as to control the surface temperature of the pair of forming rolls. Hereinafter, the “molten glass weir member” is simply expressed as “weir”.

The glass molding method of the present invention is a glass molding method in which molten glass is introduced between a pair of molding rolls whose rotation axes are arranged in parallel with each other at a predetermined interval. Controls the surface temperature of the pair of forming rolls, and forms a pair of weirs in the upper space defined by the forming surfaces of the pair of forming rolls with an interval in the axial direction of the forming rolls. It arrange | positions and it is made to store the said molten glass between the said weirs, It is characterized by the above-mentioned.

According to the present invention, molten glass, in particular, low-viscosity molten glass can be formed into a sheet glass with uniform size and quality such as sheet width and sheet thickness by suppressing the occurrence of striae and distortion by roll-out method. Glass forming apparatus and glass forming method can be provided.

It is an external view which shows an example of embodiment of the glass forming apparatus of this invention. It is a top view which shows the shaping | molding roll and dam in the shaping | molding apparatus shown in FIG. It is a figure which shows typically the state which the molten glass of a storage part passes between a pair of shaping | molding rolls in the shaping | molding apparatus shown in FIG. It is an external view of a forming roll portion when a plurality of nozzles are provided in the forming apparatus of the embodiment of the present invention. It is sectional drawing of the longitudinal direction which shows an example of the forming roll used for the glass forming apparatus of this invention. It is sectional drawing in the surface orthogonal to the longitudinal direction which follows the YY line of the forming roll shown to FIG. 5A. It is sectional drawing of an example of the drawing roll used for the glass forming apparatus of this invention. It is an external view of the forming roll part of another example of embodiment of the glass forming apparatus of this invention. It is the top view which looked at the storage part of the molten glass of the shaping | molding apparatus shown in FIG. 7 from the top. It is sectional drawing of the longitudinal direction which shows an example of the shaping | molding roll used for the shaping | molding apparatus shown in FIG. FIG. 9B is a cross-sectional view taken along a plane orthogonal to the longitudinal direction along the YY line of the forming roll shown in FIG. 9A. It is a schematic diagram which shows the example of the cartridge heater which has an output deviation in the length direction used for the shaping | molding apparatus of this invention. It is a schematic diagram which shows the example of the cartridge heater whose output is uniform in the length direction used for the shaping | molding apparatus of this invention. It is a figure which shows arrangement | positioning of the internal heater in the forming roll shown to FIG. 9A. It is an external view of the forming roll part of another example of embodiment of the glass forming apparatus of this invention. It is sectional drawing of the longitudinal direction which shows an example of the shaping | molding roll used for the shaping | molding apparatus shown in FIG. It is sectional drawing in the surface orthogonal to the longitudinal direction which follows the YY line of the forming roll shown to FIG. 13A. It is sectional drawing of the longitudinal direction which shows another example of the forming roll used for the shaping | molding apparatus shown in FIG. FIG. 14B is a cross-sectional view taken along a plane orthogonal to the longitudinal direction along the YY line of the forming roll shown in FIG. 14A.

Embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following embodiments.
[Glass forming equipment]
The glass molding apparatus of the present invention (hereinafter referred to as “molding apparatus”) is suitably used for molding molten glass having a viscosity of 0.01 to 100 dPa · s during molding. The molding apparatus includes a pair of molding rolls whose rotation axes are arranged in parallel with each other at a predetermined interval, and an axis of the molding roll in an upper space defined by a molding surface of the pair of molding rolls. A pair of weirs arranged at intervals in the direction and forming the molten glass reservoir in the upper space, temperature adjusting means disposed at least inside the pair of forming rolls, and And control means for controlling the temperature adjusting means so as to control the surface temperature of the pair of forming rolls. Hereinafter, the axial direction of the forming roll may be simply referred to as “axial direction”.

As described above, the molding apparatus of the present invention is suitably used for molding a low-viscosity molten glass having a viscosity of 0.01 to 100 dPa · s, and further for molding a molten glass having a viscosity of 0.1 to 100 dPa · s. A higher effect is exhibited. In particular, it is suitably used in the case of glass having a steep relationship between temperature and viscosity in molten glass and extremely low viscosity from the molten state to just before solidification. Examples of such molten glass include phosphate glass, borate glass, and fluorophosphate glass.

In order to form such low-viscosity molten glass so that the size and quality such as plate width and plate thickness are uniform while suppressing the occurrence of striae and distortion by the roll-out method, a forming roll It is necessary to uniformly supply a predetermined amount of molten glass according to the amount of heat removal in the axial direction of the forming roll. However, for example, for a low-viscosity molten glass having a viscosity of 0.01 to 100 dPa · s, when the predetermined amount is discharged by a slit-shaped supply nozzle having a length close to the width of the glass plate to be formed, the surface tension is reduced. Due to the influence, the liquid droplets are ejected in the form of discontinuous droplets, so-called waterfall stripes, and the boundary portion of each droplet becomes a source of striae. Further, when the discharge amount of the molten glass is increased to such an amount that the molten glass is discharged continuously and uniformly in such a slit-shaped supply nozzle, the molten glass is supplied to the forming roll exceeding the upper limit of the heat removal amount. As a result, solidification cannot be performed sufficiently, causing striae and distortion. Furthermore, the roll-out method has a steep relationship between temperature and viscosity, especially in molten glass, in order to achieve uniform size and quality such as plate width and thickness while suppressing the occurrence of striae and distortion. In such a molten glass, it is required to appropriately control the surface temperature of the forming roll in order to appropriately manage the viscosity of the molten glass.

According to the forming apparatus of the present invention, by providing a pair of weirs that form a storage portion for molten glass in the upper space portion of the pair of forming rolls, the molten glass is stored in the entire area between the weirs. A predetermined amount of molten glass passing through the pair of forming rolls can be supplied uniformly in the axial direction of the forming roll. Moreover, the viscosity of a molten glass can be made high by lengthening the contact time of a molten glass and a forming roll by the said storage. Furthermore, by providing a temperature adjusting means at least inside the forming roll and a control means for controlling it, the surface temperature of the forming roll can be appropriately controlled to be a desired temperature, and the viscosity of the molten glass is appropriately managed. it can. Thus, the molten glass can be molded by a roll whose surface temperature is controlled to the optimum molding temperature from the start of molding. Therefore, immediately after the start of molding, a solidified glass having excellent surface properties and a desired width and continuous in the width direction can be obtained.

In the molding apparatus of the present invention, the method for supplying the molten glass to the reservoir is not limited, but in order to continuously supply the molten glass, for example, a tubular tube provided in the center in the roll width direction, rather than a slit-shaped supply nozzle. It is desirable to adopt a supply method in which molten glass is supplied from the supply nozzle and is uniformly rolled out as the glass flows through the storage portion. In that case, the temperature of the molten glass in the reservoir may have a distribution in the axial direction of the forming roll, which may reduce the thickness and quality uniformity in the width direction of the plate glass obtained by forming.

Therefore, in order to further improve the thickness and quality uniformity in the width direction of the obtained plate glass, the molding apparatus of the present invention further includes a molten glass temperature measuring means for measuring the temperature distribution of the molten glass in the storage section. Preferably, the control means controls the temperature adjusting means based on the temperature distribution data of the molten glass measured by the measuring means. In this case, the temperature adjusting means includes a refrigerant flow path and an internal heater whose output distribution is variable in the axial direction, which is built in the axial direction of the forming roll, or a refrigerant which is built in the axial direction of the forming roll. The structure provided with the ring-shaped heater arrange | positioned on the outer peripheral surface of the flow path and the edge part vicinity of the said forming roll is preferable. In addition to the refrigerant flow path and the ring heater, the temperature adjusting means may include an internal heater that is built in the axial direction of the forming roll. Hereinafter, “molten glass temperature measuring means” is simply expressed as “thermometer”.

In the molding apparatus of the present invention, the above configuration enables molding with uniform size and quality such as sheet width and sheet thickness while suppressing striae and distortion of the low-viscosity molten glass by the roll-out method. did. In the roll-out method, when the molten glass to be used has a glass composition composed of highly volatile components, the exposure time to the atmosphere is shortened, and the unevenness of components due to the loss of volatile components can be suppressed. it can.
Hereinafter, the molding apparatus of the present invention will be specifically described. FIG. 1 is an external view showing an example of an embodiment of a glass forming apparatus of the present invention.

The forming apparatus 1 includes a pair of forming rolls 2 and a pair of weirs 3 that are disposed in an upper space defined by the forming surfaces of the pair of forming rolls 2 to form a storage portion P for molten glass Gm. And a temperature adjusting means 4 built in the pair of forming rolls, and a control means (not shown) for controlling the surface temperature of the pair of forming rolls 2 by controlling the temperature adjusting means 4. Between the pair of weirs 3, for example, a nozzle 5 is provided through which a molten glass Gm having a viscosity of 0.01 to 100 dPa · s flows down. Further, on the lower side of the pair of forming rolls 2, for example, a slow cooling means 6, a drawing roll 7, a cutting means 8 and the like are provided in this order.

FIG. 2 is a plan view showing the forming roll 2 and the weir 3 in the forming apparatus shown in FIG. FIG. 3 is a diagram schematically illustrating a state in which the molten glass stored in the storage portion P in the molding apparatus illustrated in FIG. 1 passes between a pair of molding rolls and is molded.

In the molding apparatus 1 according to the embodiment of the present invention shown in FIGS. 1 to 3, a pair of molding rolls 2 having the same outer diameter are disposed horizontally so that their rotational axes X are parallel to each other, and the desired In order to obtain a glass plate having a thickness of 5 mm, a gap S having a predetermined width is provided between the forming rolls 2. The gap S refers to the distance between the forming points Z when the point at which the pair of forming rolls 2 are closest to each other is the forming point Z. That is, the gap S is the minimum distance between the pair of forming rolls 2. The pair of weirs 3 are arranged in the upper space portion of the space section defined by the molding surfaces of the pair of molding rolls 2 as shown in FIGS. Arranged at intervals. The distance L between the opposing surfaces of the weir can be appropriately changed according to the desired width of the glass plate Gs.

The weir 3 has, for example, a substantially inverted triangular shape, and is provided with curved portions recessed inward at portions corresponding to the two sides on the lower side. The curved surface portion is formed so as to have a slight gap, such as a gap of 0.5 mm or less, in which the molten glass Gm does not flow out between each molding roll 2 or between the respective molding rolls. The curvature radius is approximately equal to the curvature radius of 2. Here, the abbreviation refers to a state that looks like that when observed with the naked eye or a state close to such a concept.

Usually, the retaining member (not shown) is connected to the upper portion of the weir 3 and the position of the weir 3 is fixed with respect to the forming roll 2 so as to be in sliding contact with the forming roll 2 or to have a predetermined gap. . In addition, the shape of the weir 3 should just be what can store the molten glass Gm effectively, for example, may have a connection part with a holding member, etc., and has the above-mentioned substantially inverted triangle shape at least partially If it is. Here, the substantially inverted triangular shape is a shape having an acute angle on the lower side, and indicates a shape having two arc-shaped sides along the curvature of the forming rolls on both sides.

The lower end of the weir 3 is preferably provided at a position where the distance L1, which is the shortest distance from the forming point Z of the pair of forming rolls 2, is 0 to 5 mm, and more preferably the position where the distance is 0 to 0.5 mm. preferable. By providing the lower end part to such a position, the outflow of the molten glass Gm from the lower end part side to the outside can be suppressed, and the molding can be performed effectively. The lower end portion of the weir 3 may be provided up to a position lower than the above position, but is usually set to the forming point Z. For the same reason, it is preferable to provide the lower end portion of the curved surface portion up to the same position as the lower end portion of the weir 3 described above.

On the other hand, the upper portion of the weir 3 has a vertical distance L2 from the straight line H passing through the forming point Z of the pair of forming rolls 2 and the center of the pair of forming rolls 2 and is preferably the radius of the forming roll 2. It is preferable to provide in the position which becomes 9/10 or more. In addition, when the position of the uppermost part of a pair of forming rolls 2 is different, the upper part of the weir 3 is a position higher by 9/10 or more of the radius of the forming roll 2 from the center of the forming roll 2 having the lowermost position. It is preferable that it exists in.

By providing the upper portion of the weir 3 to the above position, the molten glass Gm necessary for forming can be sufficiently stored, and the forming can be performed effectively. For the same reason, it is preferable to provide the upper portion of the curved surface portion up to the above position. Note that there may be a height difference in the upper portion of the weir 3, and in this case, it is only necessary that the lowest portion is provided up to the above position. In addition, as already demonstrated, the connection part with a holding member, etc. may be provided in the upper part of the weir 3, and the upper part of the weir 3 is provided to a position higher than the said position for such a connection part. It may be done.

The thickness of the weir 3 is preferably 1 to 20 mm from the viewpoints of high-temperature strength, durability, workability, and economy. With such a thickness, the molten glass Gm can be effectively stored while ensuring high-temperature strength, durability, workability, and economy.

The constituent material of the weir 3 is not particularly limited as long as it is excellent in heat resistance, releasability and workability, and a known heat insulation board or the like can be used. For example, a composite material in which a reinforcing material made of heat resistant fiber such as glass fiber or aramid fiber is combined, and a ceramic sintered body are preferable. As the composite material, for example, an inorganic composite material made of a reinforcing material made of heat-resistant fiber such as glass fiber or aramid fiber and an inorganic binder such as cement or calcium silicate can be mentioned as a suitable material. A commercially available product can be used as the inorganic composite material, and Rosna board (trade name, manufactured by Nikko Kasei Co., Ltd.) is particularly preferably used from the viewpoint of releasability. As the ceramic sintered body, a boron nitride sintered body is preferably used particularly from the viewpoint of releasability.

Further, the constituent material of the weir 3 is preferably a material having low thermal conductivity at the molding temperature of the molten glass to be used from the viewpoint of suppressing partial solidification due to the rapid cooling of the molten glass Gm. For example, in the case of phosphate glass, borate glass, or fluorophosphate glass, the molding temperature is preferably 250 to 700 ° C., and the thermal conductivity is low at the molding temperature, specifically, the thermal conductivity is 10 W. / M · K or less is preferable, and 1 W / m · K or less is more preferable. Here, in the present specification, the molding temperature of the molten glass refers to a temperature region when the molten glass is molded. Specifically, the temperature from when the molten glass is supplied to the molding apparatus in a molten state until immediately before solidification. An area.

As shown in FIG. 1, when forming molten glass, molten glass Gm is continuously supplied and stored in the storage portion P from a melting kiln outside the forming apparatus 1 through a nozzle 5. The nozzle 5 is disposed between the weirs 3, and is preferably disposed on the central portion between the weirs 3 from the viewpoint of evenly spreading and storing the molten glass Gm in the axial direction of the forming roll 2. When forming a seamless glass plate Gs, it is preferable to provide only one nozzle 5 as in the forming apparatus 1 shown in FIG.

When the glass plate Gs may have a seam, such as when the glass plate Gs is cut into small pieces after forming, for example, as shown in FIG. 4, an equal interval is provided between the weirs 3 of the forming apparatus 1. A plurality of nozzles 5 may be provided. The shape of the opening of the nozzle 5 is not particularly limited, and for example, a circular shape, an elliptical shape, and a rectangular shape are preferable. For example, when the opening is circular, the diameter is preferably 1 to 12 mm.

For example, when the opening of the nozzle 5 has a slit-like shape and the molten glass Gm flowing down from the nozzle 5 has a waterfall stripe shape, the liquid droplets are combined and a storage portion is formed between the pair of forming rolls 2. When forming, optical defects called striae are likely to occur at the interface of each droplet. Therefore, in order to perform plate forming so that optical defects such as striae do not occur, it is preferable that the molten glass Gm flows continuously. Therefore, the shape of the opening of the nozzle 5 is preferably circular, elliptical, or rectangular. In addition, the nozzle 5 is preferably disposed at one position at the center or one end in the axial direction of the pair of forming rolls 2 or a plurality of positions when an optical defect formed by the interface does not remain in the product. . According to such a shape and arrangement, higher-quality plate forming can be performed by a forming method in which the molten glass Gm is expanded in the width direction using the storage portion.

The storage amount of the molten glass Gm stored in the storage part P is appropriately selected depending on the viscosity of the molten glass, the molding temperature, and other molding conditions. Usually, if the shaping | molding apparatus 1 is fixed, the storage amount of the molten glass Gm will be the storage width W shown by FIG. 3, ie, the width between the molding surfaces in the upper surface of the stored material which consists of molten glass Gm, in other words, storage. It can show by the space | interval of the line | wire which the interface with the air | atmosphere of the made molten glass Gm contact | connects a pair of forming rolls 2. FIG. The surface area at which the molten glass Gm is in contact with the atmosphere in the reservoir P is determined by the product of the width W and length of the reservoir P, that is, the distance L between the pair of weirs 3. Compared with the conventional casting method, the area in contact with the atmosphere is extremely small, and the loss of volatile components is suppressed.

The molten glass Gm supplied from the nozzle 5 and stored in the storage portion P is moved downwardly from the gap S between the forming rolls 2 with the rotation of the pair of forming rolls 2. That is, the glass plate Gs formed into a plate shape having the same width as the storage portion is continuously extruded. The flow rate of the molten glass Gm from the nozzle 5 to the storage part P is preferably set to a flow rate that is discontinuous in the width direction, for example, so as not to form a waterfall pattern. Specifically, the peripheral speed of the forming roll 2 The amount of glass to be formed and extruded is determined according to the setting of the gap S between the weirs 3 and the like. Thereby, the quantity of the molten glass Gm stored in the storage part P also becomes fixed. In order to keep the amount of the molten glass Gm stored in the storage portion P constant, for example, in FIG. 3, the melting is performed from a forming point Z of a pair of forming rolls and a straight line H passing through the center of the pair of forming rolls. The distance K to the upper surface of the storage made of glass Gm may be kept constant. The molten glass Gm supplied to the storage part P reaches the gap S by the rotation of the molding roll 2 while decreasing the temperature by contacting the molding roll 2 whose surface temperature is controlled, and between the molding rolls 2 at an appropriate molding temperature. Is pushed out of the forming roll 2.

For example, the outer diameter of the pair of forming rolls 2 is 100 mm, the gap S between the forming rolls 2 is 1 mm, the distance L between the pair of weirs 3 is 200 mm, and the amount of molten glass Gm stored is stored. When W is 10 mm when indicated by the width W, the contact time of the molten glass Gm with the forming roll 2 is calculated as 1.6 seconds if the peripheral speed of the forming roll 2 is 800 mm / min. Similarly, when W is 30 mm under the above conditions, if the peripheral speed of the forming roll 2 is 800 mm / min, the contact time of the molten glass Gm with the forming roll 2 is calculated as 2.9 seconds. When the molten glass Gm is cooled and extruded from the forming roll 2 during the contact time, the molten glass Gm is solidified to become the glass plate Gs. In any of the above cases, the glass plate Gs is formed at 800 mm / min. Therefore, the supply amount of the molten glass Gm is calculated as 160 ml / min.

Thus, according to the shaping | molding apparatus 1 of embodiment of this invention, the amount of flowing-down of the molten glass Gm supplied to the storage part P from the nozzle 5, and the glass shaping speed of a rollout, in other words, the shaping | molding roll 2 out. It is possible to maintain a balance with the amount of the glass plate Gs to be pushed out, whereby the amount of the molten glass Gm stored in the storage portion P can be made constant. As a result, a plate glass having a desired plate width and continuous in the width direction can be formed. In particular, when the viscosity of the molten glass Gm is 0.01 to 100 dPa · s, it can be molded more effectively than before.

In the molding apparatus 1 shown in FIGS. 1 to 3, the pair of molding rolls 2 have the same size, but the outer diameter of the molding roll 2 in the molding apparatus according to the embodiment of the present invention is a pair of molding rolls. The two may be the same or different. Also, the vertical position of the rotating shaft at this time may be the same or different. Even if the outer diameters of the pair of forming rolls 2 are different, the peripheral speeds are made constant. In the present specification, the outer diameter of the forming roll 2 refers to the outer diameter of a portion of the forming roll 2 where the molten glass reservoir is formed.

The forming roll 2 can reduce the thickness T of the glass plate Gs as the outer diameter is reduced, but preferably has a certain outer diameter from the viewpoint of providing the temperature adjusting means 4 described below, for example, 30 Is preferably 200 to 200 mm, and more preferably 50 to 100 mm.

Also, the length of the pair of forming rolls 2 may be the same or different between the pair of forming rolls 2 as with the outer diameter. It is essential that the length of the pair of forming rolls 2 is longer than at least the width of the glass plate Gs obtained by forming and the width of the pair of weirs 3 described above. In order to efficiently control the temperature, the length of the pair of forming rolls 2 is preferably 1 to 20 mm longer than the width of the glass plate Gs to be formed. In the present specification, the length of the forming roll 2 refers to the length of the portion having the outer diameter in the forming roll 2. Here, when a forming roll has a flange, the length of the part except a flange is said. In the forming roll 2 used in the forming apparatus according to the embodiment of the present invention, the outer diameter and length of the pair of forming rolls 2 are preferably the same from the viewpoint of controlling the surface temperature.

The pair of weirs 3 are damming members for damming the molten glass Gm, and are arranged in the upper space portion of the space portion defined by the molding surface of the pair of molding rolls 2 as shown in FIG. And are arranged at intervals in the axial direction of the forming roll 2. This distance, that is, the distance between the inner surfaces of the pair of weirs 3 can be appropriately changed according to the desired width L of the glass plate Gs, but is preferably 50 to 300 mm, for example.

As a method of making the peripheral speeds of the pair of forming rolls 2 equal to each other, each of the forming rolls 2 can be controlled independently by connecting a driving device, and each gear roll can be adjusted by adjusting the gear ratio using only one driving device. A method for adjusting the peripheral speed of the forming roll 2 is exemplified. Examples of the driving device include those equipped with a continuously variable transmission mechanism and variable motors such as servo motors. The driving device is connected to the forming roll 2 so that the straight line passing through the center of the forming roll 2 in the axial direction becomes the rotation axis X and the entire forming roll rotates.

Note that the peripheral speed of the forming roll 2 when forming the glass sheet using the forming apparatus of the embodiment of the present invention is preferably 300 to 2000 mm / min. By setting the peripheral speed to 2000 mm / min or less, the contact time with the molten glass Gm can be lengthened and sufficiently cooled and solidified. Moreover, by making peripheral speed into 300 mm / min or more, while improving productivity, it can suppress that the plate | board thickness of the glass plate Gs becomes thick too much.

The forming roll 2 has a temperature adjusting means 4 at least inside the forming roll 2 and a control means for controlling the temperature adjusting means 4 although not shown. By controlling the temperature adjusting means 4 by the control means, the surface temperature of the forming roll 2 can be controlled to an appropriate temperature. The molding apparatus according to the embodiment of the present invention includes the temperature adjusting means 4 and the control means for controlling the temperature adjusting means 4 together with the pair of weirs 3, so that the molten glass Gm, particularly phosphate glass, borate A molten glass Gm having a viscosity of 0.01 to 100 dPa · s made of glass, fluorophosphate glass, or the like can be appropriately formed into a glass plate Gs.

The surface temperature of the forming roll 2 when forming the glass sheet using the forming apparatus according to the embodiment of the present invention is preferably 250 to 700 ° C, and more preferably 280 to 480 ° C. By setting the surface temperature of the forming roll 2 to 700 ° C. or less, the molten glass Gm can be cooled and solidified, and seizure of the molten glass Gm on the surface can be suppressed. Moreover, the surface temperature of the shaping | molding roll 2 shall be 250 degreeC or more, and the surface wrinkle and crack which generate | occur | produce by rapid cooling can be suppressed. The surface temperature of the forming roll 2 is an intermediate portion in the axial direction of the pair of forming rolls 2 and is opposite to the forming point Z at which the pair of forming rolls 2 are closest as shown in FIG. Measured at the surface portion.

Examples of the temperature adjusting means 4 include cooling means such as a coolant channel for circulating a coolant such as cooling water in the inside of the forming roll 2, particularly in the vicinity of the rotation axis X. When such a refrigerant flow path is used as the temperature adjusting means 4, the control means for controlling the cooling means for controlling the surface temperature of the forming roll 2 is usually a means for mainly adjusting the flow rate of the refrigerant. For example, a flow rate adjusting valve or the like is used.

Here, when the refrigerant flow path and the control means are used in combination, the flow rate dependence of the cooling capacity is low in the stable region, and the temperature adjustment range by the flow rate control is narrow. May not be able to cope with the need for precise control. Specifically, when the surface temperature of the forming roll 2 is excessively lowered, it takes time to return to an appropriate temperature. For this reason, in addition to the cooling means, it is preferable to provide a heating means including a heater having a wide adjustment range of the surface temperature in the vicinity of the surface of the forming roll 2 as the temperature adjusting means 4. When a heater is used as the heating means, examples of the control means for controlling the heater include a power source capable of adjusting output. For example, the surface temperature of the forming roll 2 can be controlled by controlling the heating means by changing the output from 0 to the maximum output value in this power source.

In the molding apparatus 1 according to the embodiment of the present invention, as an example of the molding roll 2A having the refrigerant flow path for circulating the cooling water and the heater as the temperature adjusting means 4, the molding roll 2A is shown in FIGS. 5A and 5B. . 5A is a cross-sectional view of the forming roll 2A in the longitudinal direction, and FIG. 5B is a cross-sectional view of the forming roll 2A shown in FIG. 5A on a plane orthogonal to the longitudinal direction along the YY line.

The forming roll 2A has a cylindrical roll body 20 having a refrigerant flow path 24 disposed in the center in the axial direction, and is concentrically inside the roll body 20 outside the refrigerant flow path 24. It has a plurality of internal heaters 25 arranged along the axial direction, and has a coating layer 23 whose peripheral surface formed concentrically on the roll body 20 is a glass molding surface. Further, the forming roll 2A includes a tubular member 29 that is integrally formed at both ends of the roll main body 20 so that the centers of the cross sections perpendicular to the roll main body 20 and the axial direction coincide with each other. The tubular member 29 is usually connected to a driving device (not shown), and a straight line passing through the center of the roll body 20 from the tubular member 29 in the axial direction becomes the rotation axis X, and the tubular member 29 rotates to form the forming roll 2A. This is a mechanism that rotates as a whole.

In the forming roll 2A, a cylindrical hole is formed in the center of the roll body 20 along the axial direction so that one end is connected to one tubular member 29 and the other end is closed. By further including an inner tube 27 having both ends opened on the inner side, a refrigerant flow channel 24 formed by the outer wall of the inner tube 27 and the inner wall of the roll body 20 and the inner wall of the inner tube 27 is formed. 24 is formed. Further, the inner tube 27 is continuously provided up to the inside of the tubular member 29.

Here, the cooling water usually passes through the inner flow path of the inner tube 27 in the tubular member 29 and is continuously installed from the tubular member 29 in the cylindrical hole of the forming roll 2A. Into the refrigerant flow path 24 formed by the inner wall of the inner wall of the cylindrical hole, folded back when reaching the closed end of the cylindrical hole, and enters the refrigerant flow path 24 composed of the outer wall of the inner tube 27 and the inner wall of the roll body 20, After passing through the refrigerant flow path 24, the refrigerant flows out from the same end as the inflow side into a flow path formed by the outer wall of the inner tube 27 and the inner wall of the tubular member 29. The cooling water repeats circulation in which heat is exchanged outside the forming roll 2A and is supplied again to the forming roll 2A. Further, the flow rate control of the cooling water may be performed by providing a flow rate adjusting valve or the like in the circulation channel after heat exchange.
In addition, the flow path 24 for refrigerant | coolants may be formed in the form which penetrates the roll main body 20 from one tubular member 29, and is connected to the other tubular member 29 as needed. Moreover, although water is preferable as a refrigerant | coolant, even if it is other than water, if it is a compound and composition which function as a refrigerant | coolant, it can be used without a restriction | limiting in particular.

The diameter of the cylindrical hole that the roll body 20 has for forming the refrigerant flow path 24 is about 1/10 to 6/10 of the outer diameter of the forming roll 2A, and preferably 20 mm or more. Further, the position of the closed end is preferably a position farther from the supply and discharge side than the arrangement position of the weir 3 near the end of the forming roll 2A opposite to the supply and discharge side of the cooling water. Further, as the size of the inner tube 27, the tube thickness indicated by (outer diameter−inner diameter) / 2 of the inner tube 27 is about 0.3 to 10 mm, and the outer diameter is 1/5 of the diameter of the cylindrical hole. It is preferably about 2/3. Hereinafter, the tube thickness and thickness of the tubular member refer to the thickness indicated by (outer diameter−inner diameter) / 2 unless otherwise specified.

Examples of the plurality of internal heaters 25 that are concentrically disposed along the axial direction inside the roll body 20 outside the refrigerant flow path 24 include a cartridge heater and an induction heater. The internal heater 25 is attached to, for example, the end of the roll body 20 opposite to the supply and discharge side of the cooling water so that the heater body is disposed in the roll body 20 as described above. The internal heater 25 is connected to a power source capable of adjusting the output outside the forming roll 2 </ b> A by a wiring 33 provided so as to pass through the tubular member 29 from the attachment portion. A more preferable aspect of the arrangement and number of the internal heaters 25 is as described later. Instead of the internal heater 25, for example, a small combustion burner or a heat medium may be used.

The constituent material of the roll body 20 is not necessarily limited as long as it has high rigidity and toughness and high surface hardness. For example, an iron-based material or a copper-based material is preferably used. As described above, the surface temperature of the forming roll when the glass is formed using the forming apparatus of the present invention is preferably 250 to 700 ° C. For example, this temperature region corresponds to the softening point temperature region of the glass when phosphate glass, borate glass or fluorophosphate glass is used as the molten glass. The material constituting the roll body 20 is preferably a material having a high thermal conductivity in this temperature range, specifically a material having a thermal conductivity of 10 to 400 W / m · K, preferably 40 to 380 W / m · K. A material that is

If a material having a thermal conductivity in the above range is used as the constituent material of the roll body 20, the latent heat brought in by the molten glass Gm supplied from the nozzle 5 to the central portion of the storage portion of the forming roll 2A is formed by the forming roll. 2A can be efficiently dispersed in the axial direction. When the thermal conductivity of the constituent material of the roll body 20 is lower than the lower limit, only the central portion may be heated to cause glass seizure due to local overheating of the central portion of the forming roll 2A.

High thermal conductivity materials having a thermal conductivity in the above range include iron (25 to 55 W / m · K) or low carbon steel (25 to 45 W / m · K) equivalent thereto, high carbon cast iron (20 to 55 W / m · K), copper (340 to 380 W / m · K) or a copper alloy reinforced with chromium, zirconia, alumina, etc. (alloy whose composition is adjusted to 280 to 320 W / m · K), Aluminum (220 to 240 W / m · K) or an aluminum alloy reinforced with copper, zinc, magnesium, beryllium or the like (alloy whose composition is adjusted to 100 to 200 W / m · K) or the like is preferable. Among these, copper or a copper alloy reinforced with chromium, zirconia, alumina or the like is more preferable. The thermal conductivity shown in parentheses after each material is the thermal conductivity in the softening point temperature range of 250 to 700 ° C. of phosphate glass, borate glass or fluorophosphate glass.

Further, the constituent material of the roll body 20 is not necessarily the same in the axial direction. For example, the temperature distribution of the molten glass Gm in the axial direction of the forming roll 2A is uniform, particularly the portion immediately below the nozzle 5, that is, the molten material. From the viewpoint of dispersing the heat of the portion where the glass Gm flows down, the portion is made of a material having a high thermal conductivity, for example, a material having a thermal conductivity in the above range, and the other portions are heated more than the material having the high thermal conductivity. A material with low conductivity may be used.

The thickness indicated by (outer diameter−inner diameter) / 2 of the roll body 20 is preferably 10 to 80 mm, more preferably 20 to 50 mm from the above viewpoint and from the point of incorporating the internal heater 25. .
In addition, the roll main body 20 may be formed by two layers of the center member 21 and the intermediate | middle layer 22, as needed, for example like the below-mentioned forming roll 2B. Moreover, the two layers of the roll main body 20 and the coating layer 23 may be formed by one layer without distinction. When the center member 21, the intermediate layer 22, and the covering layer 23 are configured, each layer may be configured by a plurality of layers. Moreover, you may have the flange 26 as needed.

The forming roll 2A has a coating layer 23 that is formed concentrically on the roll body 20 and whose peripheral surface is a glass forming surface. In the molding roll used in the molding apparatus of the present invention, such a coating layer is not an essential component, but is a preferably provided component.
The covering layer 23 has a good releasability from the molten glass Gm and is formed of a material that does not react with the components of the molten glass Gm. Moreover, since it contacts directly with the molten glass Gm, heat resistance is required.

The coating layer 23 is a layer provided on the roll body 20 by surface-treating the roll body 20 by a conventionally known method such as plating, thermal spraying, ion plating, or nitriding. Also good. Specific examples of the material constituting the coating layer 23 include various heat resistant plating layers, such as Ni—B—W alloy plating layers, hard chrome plating layers, thermal spray layers, such as Cr ₃ C ₂ thermal spray layers, and Y—Zr thermal sprays. Layer, chrome / copper alloy layer, SUS420J2 layer, pure iron layer, and the like. Among these, from the viewpoint of releasability, Ni—B—W alloy plating layer, hard chrome plating layer, SUS420J2 layer and the like are preferable, and further, properties such as releasability, heat resistance, and non-reaction with molten glass Gm are preferable. A good Ni—B—W alloy plating layer is more preferably used.

The surface of the coating layer 23 may be subjected to a process for adjusting the surface roughness by sandblasting, etching, or the like in order to obtain releasability. The thickness of the coating layer 23 is not particularly limited as long as the above function can be achieved, but is preferably 0.001 to 1.0 mm, and more preferably 0.01 to 0.05 mm.

As mentioned above, the structure of the forming roll 2A has been specifically described in one unit. However, the description of one of the one pair is applied to the other, and the same structure is preferable in one pair.

As shown in FIG. 1, in the molding apparatus 1 according to the embodiment of the present invention, the glass plate Gs extruded from the molding roll 2 passes through the drawing roll 7 through the slow cooling region by the slow cooling means 6, and then the cutting means 8. It is cut by.

The slow cooling means 6 is provided in order to suppress the occurrence of cracks due to rapid cooling of the glass plate Gs. For example, the slow cooling means 6 is provided along the traveling direction so as to cover both main surfaces of the glass plate Gs. The slow cooling means 6 is preferably provided in a range of about 200 to 20000 mm downward from a position of 0 to 300 mm in the vertical direction from the lower end of the forming roll 2. The temperature is preferably set so that the temperature gradually decreases. The temperature on the inlet side, that is, the molding roll 2 side, is preferably 200 to 500 ° C., and the temperature on the outlet side is preferably 25 to 400 ° C. By setting it as such a range and a temperature gradient, generation | occurrence | production of a crack etc. can be suppressed effectively.

The drawing roll 7 is disposed at the lower part of the slow cooling means 6 and rotates so as to be pulled downward while sandwiching the glass plates Gs discharged from the slow cooling means 6 from both main surface sides. By providing such a drawing roll 7, a glass plate Gs closer to a flat plate shape can be obtained. The drawing roll 7 is preferably one that can be securely clamped so that the glass plate Gs does not slip and is not damaged. For example, as shown in FIG. 6, the surface of the core 71 made of stainless steel or the like is heat resistant. Examples thereof include a case where the intermediate coating layer 72 made of a fiber felt is coated and the intermediate coating layer is coated with a surface protective layer 73 made of silica cloth.

As the intermediate coating layer 72, for example, a felt made of carbon fiber, polyparaphenylene benzoxazole (PBO) fiber, aramid fiber or the like is preferably used. As the surface protective layer 73, for example, a woven fabric made of silica fiber coated with a heat-resistant treatment agent or the like is preferably used. According to such a thing, while being able to hold | grip reliably by suppressing the slip of the glass plate Gs, it can be sufficient durability. The size of the drawing roll 7 is not necessarily limited. For example, the diameter of the core material 71 is 30 to 200 mm, the thickness of the intermediate coating layer 72 is 2 to 20 mm, and the thickness of the surface protective layer 73 is 1 to 10 mm.

The cutting means 8 is provided to cut the long glass plate Gs to make it short. Examples of the cutting means 8 include those that are cut using a diamond cutter, a cemented carbide cutter, or a laser cutter after cooling. Further, for example, the surface may be cut with a cutter at a temperature of about 400 ° C. during cooling, for example, and then may be cut by generating distortion by cooling with air blowing.

In the above, the shaping | molding apparatus 1 of embodiment of this invention shown in FIG. 1 was demonstrated. Here, as the temperature adjusting means that the forming roll used in the forming apparatus of the present invention has at least inside, the cooling means described above or a combination of the cooling means and the heating means, for example, in FIGS. 5A and 5B Instead of the combination of the cooling means and the heating means shown in the figure, a cooling heating means that circulates a heat medium made of molten metal, synthetic oil, particularly high-temperature synthetic oil, and performs both cooling and heating may be used. Good. According to the cooling and heating means using such a heat medium, the temperature can be controlled by cooling or heating the heat medium, so that the structure can be simplified compared to the case where the cooling means and the heating means are provided separately. Examples of the molten metal serving as the heat medium include sodium, gallium, and tin. Examples of the synthetic oil include Barrel Therm 400 (trade name, manufactured by Matsumura Oil Co., Ltd.).

Although the temperature adjusting means can be simplified by using synthetic oil, if the synthetic oil stays inside the forming roll for some reason, the synthetic oil may become hot and ignite. For this reason, it is preferable to provide a discharge valve that discharges the synthetic oil in a part of the circulation flow path and a forced discharge means that pushes the synthetic oil inside the molding roll toward the discharge valve by compressed air or the like. In addition to these, measuring means for measuring the flow rate and temperature in a part of the circulation flow path and generating an abnormal signal when the measured value becomes an abnormal value, and receiving the abnormal signal, the emergency discharge valve is It is preferable to provide an emergency discharge system that is opened and includes automatic means for driving the forced discharge means.

Here, although it depends on the method of supplying molten glass such as the shape and number of nozzles, the molten glass Gm in the storage part P is normally stored unless the supply of the molten glass is performed uniformly over the entire storage part P. A temperature difference occurs depending on the position of the part. For example, when the molten glass Gm is supplied from one nozzle 5 to the central portion of the storage portion P as shown in FIG. 1, a large temperature distribution is generated in the axial direction of the forming roll 2. Specifically, the temperature of the molten glass Gm in the storage part P is as high as the temperature at the time of supply in the central part, and tends to become gradually low toward the interface with the weir 3.

From the viewpoint of uniformizing the temperature distribution of the molten glass in the axial direction of such a forming roll, at least a temperature provided inside the forming roll in order to control the surface temperature of the forming roll corresponding to the temperature difference of the molten glass. The adjusting means is preferably one that effectively cools the portion immediately below the nozzle, that is, the portion where the molten glass Gm first flows down. As such a thing, for example, in the forming roll 2A shown in FIGS. 5A and 5B, the diameter of the flow passage 24 for the refrigerant in the part is increased to reduce the thickness of the roll body 20, and the cooling capacity of this part. And the like adjusted. Further, for example, the part may be cooled using a temperature adjusting means provided outside the forming roll as described later, or the part other than the part may be heated.

Thus, in the molding apparatus of the present invention, the temperature of the molten glass in the storage portion has a distribution in the axial direction of the molding roll in order to further improve the thickness and quality uniformity in the width direction of the obtained glass sheet. It is preferable to control the surface temperature of the forming roll so as to be distributed in the axial direction in accordance with the temperature of the molten glass in the reservoir. Specifically, the molding apparatus of the present invention has a thermometer that measures the temperature distribution of the molten glass in the reservoir in addition to the above-described configuration, and is based on the temperature distribution data of the molten glass measured by this thermometer. Thus, an embodiment in which the control means controls the temperature adjustment means is preferable.

In this case, the temperature adjusting means includes a refrigerant flow path that is built in the axial direction of the molding roll and an internal heater that has a variable output distribution in the axial direction, or a refrigerant flow path that is built in the axial direction of the molding roll. And the structure provided with the ring-shaped heater arrange | positioned on the outer peripheral surface of the edge part vicinity of a forming roll is preferable. Further, the temperature adjusting means may be configured to include an internal heater built in the axial direction of the forming roll in addition to the refrigerant flow path and the ring heater. In the molding apparatus of the present invention, the surface temperature of the molding roll can be controlled by the control means controlling the temperature adjusting means. The surface temperature of the forming roll is controlled, for example, so that the temperature distribution of the molten glass is averaged.

Hereinafter, the molding apparatus according to the present invention in which the control means controls the temperature adjusting means based on the temperature distribution data of the molten glass measured by the thermometer for measuring the temperature distribution of the molten glass in the storage portion according to FIGS. 7 to 14B. The embodiment will be described.
FIG. 7 to FIG. 11 show examples of embodiments of the molding apparatus of the present invention having a refrigerant flow path and an internal heater whose output distribution is variable in the axial direction, which is incorporated in the axial direction of the molding roll as temperature adjusting means. Show. FIG. 12 to FIG. 14B show a configuration including a flow path for refrigerant built in the axial direction of the forming roll and a ring heater disposed on the outer peripheral surface near the end of the forming roll, or in addition to these, The example of embodiment of the shaping | molding apparatus of this invention of a structure provided with the internal heater internally equipped by the axial direction is shown.

The molding apparatus 1 shown in FIG. 7 is arranged in an upper space defined by a pair of molding rolls 2 and molding surfaces of the pair of molding rolls 2 to form a storage portion P for molten glass Gm. It has a pair of weirs 3 and a thermometer 9 for measuring the temperature distribution of the molten glass in the reservoir P. In addition, the pair of forming rolls 2 includes a refrigerant flow path and an internal heater whose output distribution is variable in the axial direction, which is incorporated in the axial direction as temperature adjusting means. Further, the molding apparatus 1 shown in FIG. 7 has control means (not shown) for controlling the refrigerant flow path and the internal heater based on the temperature distribution data of the molten glass measured by the thermometer 9. A nozzle 5 through which the molten glass Gm flows is provided between the weirs 3. Although not shown in FIG. 7, on the lower side of the pair of forming rolls 2, for example, a slow cooling means, a drawing roll, and a cutting means are provided in this order in the same manner as shown in FIG. .

In the molding apparatus 1 shown in FIG. 7, it has the thermometer 9 which measures the temperature of the molten glass in the storage part P, and was equipped with the temperature adjustment means which has at least the inside of the molding roll 2 in the axial direction of the molding roll. 1 can be the same as the molding apparatus 1 shown in FIG. 1 except that the refrigerant flow path and the internal heater whose output distribution is variable in the axial direction are provided. In addition, the top view which looked at the storage part P of the molten glass Gm of the shaping | molding apparatus 1 shown in FIG. 7 from the top is shown in FIG.

As the thermometer 9 included in the molding apparatus 1 shown in FIG. 7, means used for measuring the temperature of the molten glass in the molding process can be used without particular limitation. Specifically, a means for measuring the molten glass temperature in a non-contact manner, such as a radiation thermometer, a thermography, or the like is preferable. If the non-contact type thermometer 9 is used, the surface temperature of the forming roll is actually controlled while averaging the temperature distribution obtained by measuring the temperature of the molten glass Gm in the reservoir P. Rolled-out molding of molten glass can be performed.

Also, as the thermometer 9, a contact-type temperature measuring means such as a thermocouple can be used. In this case, since the temperature measurement of the molten glass and the actual molten glass roll-out molding cannot be performed simultaneously, the temperature distribution of the molten glass Gm in the storage portion P is measured in advance under the same conditions as the actual molding conditions. Next, under the molding conditions, the molten glass is actually roll-out molded while controlling the surface temperature of the molding roll based on the obtained measurement result.

Note that, as described above, the temperature distribution of the molten glass Gm in the storage part P is generally generated in the axial direction of the forming roll, and has a great influence on the quality and the like. Therefore, the temperature distribution in the forming roll axial direction of the molten glass Gm in the storage portion P is measured using the thermometer 9, and the surface temperature of the pair of forming rolls 2 is melted based on the measured temperature distribution data. If the temperature distribution in the direction of the forming roll axis of the glass Gm is controlled so as to be averaged, it is possible to make uniform the size and quality such as the width and thickness of the glass plate to be obtained.

For example, when the molding apparatus 1 shown in FIG. 7 is used, the temperature distribution in the axial direction of the molten glass Gm in the storage part P is measured, as shown in FIG. 8, the substantially central part m2 of the storage part P and a pair of weirs. 3 in the vicinity of any one of them, specifically, the molten glass Gm stored at two points of the center position m1 in the width direction of the storage part 0 to 5 mm inside from the inner wall surface of one weir 3 Measure the surface temperature. Since the temperature distribution in the axial direction of the molten glass Gm in the reservoir P is normally a symmetrical mountain-shaped temperature distribution with the center position m2 at the top, the temperature distribution in the axial direction is measured by measuring the two points m2 and m1. Can be assumed.

On the other hand, the surface temperature of the forming roll 2 where the surface temperature is controlled so as to average the temperature distribution in the axial direction of the molten glass Gm in the storage portion P is an intermediate portion in the axial direction of the pair of forming rolls 2. Then, as shown in FIG. 2, the measurement is performed at the surface portion opposite to the forming point Z at which the pair of forming rolls 2 are closest. A specific method for measuring the surface temperature of the forming roll 2 will be described in the description of the entire forming roll 2 below.

Next, the forming roll 2 used in the forming apparatus 1 shown in FIG. The forming roll 2 included in the forming apparatus 1 shown in FIG. 7 includes, as temperature adjusting means, an internal heater that has a refrigerant flow path along the axial direction and whose output distribution is variable in the axial direction is provided along the axial direction. This is a forming roll capable of temperature control with a deviation in the axial direction. The refrigerant flow path and the internal heater whose output distribution is variable in the axial direction are controlled by control means provided outside the normal forming roll, based on the temperature distribution data of the molten glass measured by the thermometer. Specifically, the surface temperature of the forming roll is controlled so as to average the temperature distribution of the molten glass.

Specifically, as a molding roll capable of temperature control having a deviation in the axial direction, a cooling medium flow path is provided along the axial direction at the center of the forming roll, and concentric with the outside of the cooling medium flow path. There is a forming roll having a plurality of internal heaters arranged in a shape, and at least one of the internal heaters is an internal heater having a different output distribution in the axial direction. In this case, it is preferable that the same number of internal heaters having different output distributions in the axial direction and internal heaters having uniform output in the axial direction are prepared and arranged alternately.

9A and 9B are preferably used in the example of the molding apparatus 1 according to the embodiment of the present invention shown in FIG. 7, and have a refrigerant flow path at the center, and are concentrically formed axially in the outer side. It is sectional drawing which shows as an example the forming roll 2B which has arrange | positioned alternately the internal heater from which output distribution differs, and the internal heater whose output is uniform in an axial direction. 9A is a cross-sectional view in the longitudinal direction of the forming roll 2B, and FIG. 9B is a cross-sectional view in a plane perpendicular to the longitudinal direction along the YY line of the forming roll 2B shown in FIG. 9A. Hereinafter, internal heaters having different output distributions in the axial direction are referred to as “output deviation heaters”, and internal heaters having uniform output in the axial direction are referred to as “uniform output heaters”.

The forming roll 2B has a cylindrical center member 21 having a refrigerant flow path 24 in the axial direction at the center, and is formed concentrically on the center member 21, and is concentrically formed inside and along the axial direction. The intermediate layer 22 in which the heaters 25A and the output uniform heater 25B are alternately arranged, and the coating layer 23 in which the peripheral surface formed concentrically on the intermediate layer 22 is a glass molding surface. The forming roll 2 </ b> B further includes a pair of disk-shaped flanges 26 that cover the end portion of the intermediate layer 22 and contact the central member 21 at the center. In the forming roll 2B, the central member 21, the intermediate layer 22, and the portion to which the flange 26 is added correspond to the roll body 20 of the forming roll 2A shown in FIGS. 5A and 5B.

9A and 9B, in one embodiment of the forming roll used in the present invention, the forming roll 2B has a three-layer laminated structure of the central member 21, the intermediate layer 22, and the covering layer 23 in the circumferential direction. In the example of the molding apparatus 1 according to the embodiment of the present invention, as long as the molding roll 2 includes a refrigerant flow path along the axial direction and an internal heater whose output distribution is variable in the axial direction, There is no particular limitation. For example, if necessary, the central member 21 and the intermediate layer 22 may be formed as one layer without distinction, and the intermediate layer 22 and the covering layer 23 are formed as one layer without distinction. Further, three layers of the central member 21, the intermediate layer 22, and the covering layer 23 may be formed as one layer without distinction. Further, the forming roll 2 may be configured to have no flange 26 in particular. Moreover, each layer of the central member 21, the intermediate | middle layer 22, and the coating layer 23 may be comprised by the some layer, respectively.

Here, in the molding apparatus 1 shown in FIG. 7, the pair of molding rolls 2 have the same size, but the outer diameter of the molding roll 2 may be the same between the pair of molding rolls 2. There may be a difference in size. Even if the outer diameters of the pair of forming rolls 2 are different, the peripheral speeds are made constant. As a method of making the peripheral speed constant, a method using a driving device similar to the molding apparatus 1 shown in FIG. 1 can be applied.

In the forming roll 2B, the driving device is usually connected to the end of the center member 21, and a straight line penetrating the center of the center member 21 in the axial direction becomes the rotation axis X so that the center member 21 rotates, so that the entire forming roll is rotated. Rotate. In addition, regarding the outer diameter of the forming roll 2B, the thickness of the glass molded body can be reduced by setting the outer diameter to a short outer diameter. However, the internal heaters 25A and 25B and the refrigerant flow path 24 provided in the forming roll 2B are provided. The range of 30 to 200 mm is preferable so as not to narrow, and 50 to 100 mm is more preferable.

The length of the pair of forming rolls 2B may be the same as or different from each other, but at least the width of the pair of weirs 3 is added to the width of the glass plate Gs obtained by forming. It is essential to be longer than the length. In order to control the temperature efficiently, the length of the portion excluding the flange 26 is preferably 1 to 20 mm longer than the width of the sheet glass to be formed. In the forming roll 2B preferably used in the forming apparatus 1 shown in FIG. 7, the outer diameter and length of the pair of forming rolls 2B are preferably the same from the viewpoint of controlling the surface temperature.

The center member 21 is connected to an external driving device as described above. Since the central member 21 has a mechanism for rotating the entire forming roll, a material having high rigidity and toughness is preferably used as the material constituting the central member 21. Specifically, the Young's modulus of the constituent material is preferably 50 GPa or more, and more preferably 200 GPa or more.

Further, the thermal conductivity of the material of the central member 21 is equivalent to the thermal conductivity of the material constituting the intermediate layer 22 described below, and the materials constituting the central member 21 and the intermediate layer 22 are the same. However, preferably, in the softening point temperature region of the molten glass to be used, the thermal conductivity of the material of the central member 21 is higher than the thermal conductivity of the material constituting the intermediate layer 22 described below. Set low. Specifically, the material of the central member 21 is such that the thermal conductivity of the material constituting the intermediate layer 22 below is 1 of the thermal conductivity of the material constituting the central member 21 in the softening point temperature region of the molten glass used. It is preferable to select a value that is more than twice and not more than 18 times.

Note that the thermal conductivity of the material constituting the intermediate layer 22 can be equivalent to the thermal conductivity of the roll body 20 in the forming roll 2A shown in FIGS. 5A and 5B. Therefore, the central member 21 and the intermediate layer 22 are integrated. In this case, the thermal conductivity of the material can be equivalent to the thermal conductivity of the roll body 20 in the forming roll 2A.

In the forming roll 2B, the amount of heat removal can be suppressed by configuring the central portion (central member 21) with a material having lower thermal conductivity and higher thermal insulation than the outer peripheral portion (intermediate layer 22) as described above. Thereby, the diameter of the flow path 24 for refrigerant | coolants arrange | positioned inside the center member 21 can be made small, roll cross-sectional area can be enlarged, and the interior space of the internal heater as an improvement of roll rigidity and a temperature adjustment means can be ensured. In addition, since the amount of heat removal during the rollout of molten glass such as phosphate glass, borate glass, and fluorophosphate glass can be maintained near the optimum surface temperature, the energy burdened by the internal heater The applied amount can be minimized, and the temperature control performance of the surface temperature in the forming roll 2B can be enhanced.

For example, when phosphate glass, borate glass or fluorophosphate glass is used as the molten glass, the molding temperature of the glass is 250 to 700 ° C., and the material for constituting the central member 21 is: In this temperature range, a material having a thermal conductivity of 10 to 100 W / m · K is preferable, and a material having a temperature of 15 to 40 W / m · K is more preferable.

As a material having a thermal conductivity in the above range, an iron-based steel type such as stainless steel, an alloy mainly composed of nickel, specifically, iron, chromium, cobalt, niobium, tungsten, molybdenum, manganese, etc. A heat-resistant and corrosion-resistant metal such as an alloy of a metal selected from a refractory metal and nickel is suitable. Further, as stainless steel, specifically, SUS310S (15 to 25 W / m · K), SUS304 (15 to 25 W / m · K), etc., as an alloy mainly composed of nickel, specifically, Inconel 600 (15 to 25 W / m · K). The thermal conductivity shown in parentheses after each material is the thermal conductivity in the softening point temperature range of 250 to 700 ° C. of phosphate glass, borate glass or fluorophosphate glass.
When the central member 21 is made of a material having a lower thermal conductivity than the intermediate layer 22, a material having a lower thermal conductivity than the material constituting the intermediate layer 22 from the materials exemplified above is used as the material constituting the central member 21. What is necessary is just to select suitably.

The outer diameter of the central member 21 is preferably 1/10 to 6/10 of the outer diameter of the forming roll 2B, and more preferably 2/10 to 5/10. The center member 21 preferably has an outer diameter of 20 mm or more in order to provide the refrigerant flow path 24 described below.

The refrigerant flow path 24 may be formed so as to penetrate the center member 21, but as shown in FIG. 9A, the inside of the center member 21 formed in a cylindrical shape with one end opened and the other end closed. Further, the refrigerant may be circulated by forming the following refrigerant flow path 24 by further including an inner tube 27 having both ends opened.

That is, the refrigerant is supplied to the refrigerant flow path 24 formed by the inner wall of the inner tube 27 from the opening end of the inner tube 27 on the opening end side of the center member 21, and the opening end of the inner tube 27 on the closing end side of the center member 21 is The refrigerant that has reached the closed end of the central member 21 is folded back, passes through the refrigerant flow path 24 composed of the outer wall of the inner tube 27 and the inner wall of the central member 21, and is discharged to the outside from the same end as the supply side. Also good. The discharged refrigerant is repeatedly circulated by heat exchange outside the forming roll 2B and supplied to the forming roll 2B again. In this case, the position of the closed end of the center member 21 is preferably a position farther from the opening end than the disposition position of the weir 3 near the end of the forming roll 2B opposite to the opening end.

As the type of refrigerant, synthetic oil, water and the like can be mentioned, but water is preferable from the viewpoint of safety and environmental resistance. The flow rate of the refrigerant is adjusted by the size of the forming roll 2B, the set surface temperature, and the like. The refrigerant flow path 24 is preferably designed so that the variable range of the refrigerant flow rate can be widened. Here, in the forming roll 2B, the refrigerant flow path 24 controls the temperature, flow rate, and the like of the refrigerant according to the setting of the control means based on the temperature distribution data of the molten glass measured by the thermometer 9, It has a function of controlling the surface temperature of the forming roll 2B as a whole on average. The surface temperature of the forming roll 2B used in the present invention shown in FIGS. 9A and 9B is controlled by a combination of the refrigerant flow path 24 and an internal heater whose output distribution is variable in the axial direction. A mechanism for causing a deviation in temperature in the axial direction is based on the action of an internal heater described later. Depending on the design, the refrigerant flow path 24 can be configured to be capable of changing the temperature in the axial direction. However, since the internal heater is superior in terms of efficiency and variability, the temperature in the axial direction is generally normal. The mechanism for providing the deviation is mainly performed by designing the internal heater so that the output distribution is variable in the axial direction.

In addition, the central member 21 has a hollow configuration by having the refrigerant flow path 24, but from the viewpoint of maintaining strength, a design in which the wall thickness of the central member 21 is 2 mm or more is preferable.

The intermediate layer 22 formed concentrically on the central member 21 of the forming roll 2B is made of the same material as the central member 21 as described above, and may be integrated as necessary. The material of the layer 22 is set so that the thermal conductivity in the softening point temperature region of the molten glass to be used is higher than the thermal conductivity in the temperature region of the material of the central member 21. Specifically, in the softening point temperature region of the molten glass to be used, the thermal conductivity of the material constituting the intermediate layer 22 is more than 1 time and not more than 18 times the thermal conductivity of the material constituting the central member 21. It is preferable to select so as to be a value.

For example, when phosphate glass, borate glass or fluorophosphate glass is used as the molten glass, the softening temperature range of the glass corresponds to a roll surface temperature of 250 to 700 ° C. during glass molding, The material constituting the layer 22 is a material having a thermal conductivity of 10 to 400 W / m · K in this temperature range, as in the material of the roll body 20 of the forming roll 2A shown in FIGS. 5A and 5B. A material having a viscosity of 40 to 380 W / m · K is more preferable.

Since it is required to disperse the latent heat of the molten glass Gm supplied from the nozzle 5 to the central portion of the storage portion of the forming roll 2B in the axial direction of the forming roll 2B, the intermediate layer 22 includes Such a material having high thermal conductivity is preferably used. Examples of the material having high thermal conductivity as the constituent material of the intermediate layer 22 include the same materials as those of the roll body 20 of the forming roll 2A shown in FIGS. 5A and 5B described above.
When the intermediate layer 22 is made of a material having higher thermal conductivity than that of the central member 21, the material constituting the intermediate layer 22 is preferably made of a material having a higher thermal conductivity than that of the material constituting the central member 21. May be appropriately selected from a material that is more than 1 time and less than or equal to 18 times the thermal conductivity of the material constituting the central member 21.

The layer thickness of the intermediate layer 22, that is, (outer diameter−inner diameter) / 2 of the intermediate layer 22 is preferably 10 to 80 mm, and preferably 20 to 50 mm from the above viewpoint and from the point of incorporating the following internal heater. It is more preferable.

About the output deviation heater 25A and the output uniform heater 25B, which are used in the forming roll 2B shown in FIGS. 9A and 9B, are arranged concentrically around the center member 21 in the intermediate layer 22 and alternately along the axial direction. Examples thereof include a cartridge heater and an induction heater. Among these, a cartridge heater that is easy to design with an output deviation in the axial direction, excellent in electrical insulation, and easy to handle is preferable.

As the output deviation heater 25A, for example, as shown in the schematic diagram of FIG. 10A, there is a cartridge heater in which the output is varied in the axial direction so that the center portion has a low output and the both end portions have a high output. Further, as the uniform output heater 25B, for example, as shown in a schematic diagram in FIG.

As shown in FIG. 10B, the cartridge heater is generally a member in which a heating wire 32 is wound around a core 34 made of a rod-shaped insulating material at a constant interval, and is inserted into the outer cylinder 31. It has a configuration in which both ends are connected to a pair of conducting wires 33a and 33b that are built into the core and communicate with an external power source. The gap between the heating wire 32 and the outer cylinder 31 is filled with an insulating material. In the cartridge heater having such a configuration, the output distribution in the length direction of the cartridge heater, that is, in the axial direction of the forming roll, can be adjusted by the winding density of the heating wires 32.

For example, in the cartridge heater 25B shown in FIG. 10B, the winding density of the heating wires 32 is uniform throughout the entire length, and therefore the output in the length direction is also uniform. On the other hand, in the cartridge heater 25A shown in FIG. 10A, the winding density of the heating wire 32 is 1 at the center when the winding density of the heating wire 32 of the cartridge heater 25B shown in FIG. 10B is 100%. / 3 is adjusted so that the winding density is 100%, and 1/3 of both ends are high output with a winding density of 150%.
Note that the density pattern in the longitudinal direction of the winding density of the heating wires shown in the cartridge heater 25A shown in FIG. 10A is an example, and is not limited to this, and can be changed as appropriate.

Here, when the molten glass Gm is supplied from one nozzle 5 to the central portion of the reservoir P as in the molding apparatus 1 shown in FIG. 7, the temperature distribution in the axial direction of the molten glass Gm in the reservoir P is The temperature distribution is a symmetrical mountain shape with the central position at which the molten glass Gm is intensively supplied from the nozzle 5 as an apex. Therefore, in the forming roll 2B shown in FIG. 9A and FIG. 9B, in order to average this, as the output deviation heater built in the forming roll 2B, the central portion has a low output and both end portions have a high output. By using a cartridge heater in which the winding density of the heating wire is adjusted in the axial direction, the surface temperature of the forming roll 2B has a symmetrical valley-shaped temperature distribution with the central position at the bottom in the axial direction.

Further, for example, in the molding apparatus 1 shown in FIG. 7, even when the temperature distribution in the axial direction of the molten glass Gm is different from the above by changing the shape and number of nozzles, the installation position, etc., the temperature is different for each case. The length of the cartridge heater used in the same manner as described above so as to control the surface temperature of the forming roll in such a temperature distribution pattern that averages the temperature distribution of the molten glass in the reservoir P measured by the total 9 What is necessary is just to adjust the winding density of the heating wire of a direction.

In the forming roll 2B, the end portions of the output deviation cartridge heater 25A and the output uniform cartridge heater 25B are fixed to the flange 26 so as to be arranged concentrically and alternately along the axial direction in the intermediate layer 22. The lead wires 33a and 33b are connected to a power source capable of adjusting the output outside the forming roll 2B. The lengths of the output deviation cartridge heater 25A and the output uniform cartridge heater 25B are set on the side where the weirs 3 are attached, closer to the end opposite to the end of the forming roll 2B on the side where they are attached. A length reaching a position far from the end is preferable.

A preferred arrangement of concentric alternating arrangements of the output deviation cartridge heater 25A and the output uniform cartridge heater 25B is shown in FIG. As shown in FIG. 11, the arrangement of the internal heaters in the forming roll 2B is such that the other two vertices are virtual isosceles triangles with the central portions of the cartridge heaters 25A and 25B as apexes serving as apex angles in the intermediate layer 22. Is arranged so that there is no gap between the adjacent isosceles triangles, in other words, the vertices on the outer periphery of the adjacent isosceles triangles are all overlapped. It is preferable. With such an arrangement, the influence of local heating of the cartridge heaters 25A and 25B can prevent the temperature distribution on the surface of the forming roll 2B.
The shape of the isosceles triangle is preferably in the range where the apex angle is 40 to 80 degrees, more preferably 50 to 70 degrees. Furthermore, it is most preferable when the apex angle is 60 degrees, that is, when the isosceles triangle is an equilateral triangle.

5A and 5B, in the case of disposing the internal heater 25, a virtual isosceles triangle with the central portion of each internal heater 25 as the apex that is the apex angle is similarly formed as described above. When the other two vertices are drawn so as to be in contact with the outer periphery of the forming roll, it is preferable to arrange them so that there is no gap between the adjacent isosceles triangles. Further, as the internal heater 25 used for the forming roll 2A, the output deviation cartridge heater 25A or the output uniform cartridge heater 25B may be used, and these are used in combination and are arranged concentrically in the same manner as the forming roll 2B. It is good.

The power source connected to each of the cartridge heaters 25A and 25B outside the forming roll 2B is based on the temperature distribution data of the molten glass Gm in the storage portion P measured by the thermometer 9, and serves as the refrigerant flow path 24 and the internal heater. Control of the control means for controlling the cartridge heaters 25A and 25B is received. Specifically, the control means refers to each of the cartridge heaters 25A while referring to the axial surface temperature distribution data of the forming roll measured by the thermometer 9 and the axial temperature distribution data of the molten glass Gm in the reservoir P. By changing the output from 0 to the maximum output value in the power source connected to 25B, the temperature distribution of the surface temperature of the forming roll 2B is controlled so as to average the temperature distribution of the molten glass in the storage portion P. To do.

The surface temperature distribution in the axial direction of the forming roll 2B is measured, for example, as shown in FIG. 9A by placing a thermocouple 28a and a thermocouple 28b having different lengths near the surface of the forming roll 2B, specifically from the forming surface. At a distance of 0.5 to 10 mm along the axial direction, the surface temperature of the forming roll 2B in the central portion in the axial direction is measured by the thermocouple 28a, and from the inner wall surface of the weir 3 by the thermocouple 28b This is performed by measuring the surface temperature of the forming roll 2B on the inner side of 0 to 20 mm. The temperature measurement positions for the surface temperature distribution in the axial direction of the forming roll 2B are positions respectively corresponding to m2 and m1 selected for measuring the temperature distribution in the axial direction of the molten glass Gm in the storage part P. The temperature distribution in the axial direction can be measured by measuring the temperature at these two points.

The coating layer 23 formed concentrically on the intermediate layer 22 of the molding roll 2B shown in FIGS. 9A and 9B and having a peripheral surface serving as a glass molding surface is the coating layer 23 of the molding roll 2A shown in FIGS. 5A and 5B. It can be the same including a preferable aspect.

The pair of disk-shaped flanges 26 covering the end of the intermediate layer 22 of the forming roll 2B and in contact with the central member 21 at the center are preferably made of a heat conductive material having a Young's modulus of 50 GPa or more. Low material is used. Specifically, the characteristics required for the constituent material of the flange 26 are the same as the material of the central member 21. That is, a material having heat insulation and high rigidity and toughness is preferably used for the flange 26. When the flange 26 is made of such a material, the temperature control performance of the surface temperature of the forming roll 2 is enhanced, and the mechanical strength of the forming roll 2 is sufficient. In addition, as a constituent material of the flange 26, specifically, the materials exemplified as the constituent material of the central member 21 can be applied as they are, including a preferable aspect. Although the thickness of the flange 26 depends on the size of the forming roll 2, it is preferably 2 to 30 mm, more preferably 5 to 20 mm.

Thus, since the flange 26 and the central member 21 can be made of the same material, one or both of the pair of flanges 26 may be integrally formed with the central member 21 depending on the design. In the forming roll 2B shown in FIG. 9A, one in which one side of the flange 26 is integrally formed with the central member 21 is used. In the forming roll 2 </ b> B, the side of the central member 21 where the refrigerant flow path 24 is closed is formed integrally with the flange 26, and the cartridge heaters 25 </ b> A and 25 </ b> B are attached to the flange 26. By this integral molding, the mechanical strength of the molding roll 2B can be increased.

Here, the integrally formed center member 21 with the flange 26 can also be designed to be detachable from the forming roll 2B, whereby the combination of the center member 21 and the intermediate layer 22 can be easily changed. Furthermore, it becomes easy to change the output of the output deviation cartridge heater 25A and the output uniform cartridge heater 25B and change the type of the heater. Even if the flange 26 and the central member 21 are not integrally molded, the central member 21 can be designed to be detachable, and in this case, the same effect as described above can be obtained.
As mentioned above, although the structure of the forming roll 2B was specifically demonstrated in one unit, the description about one which comprises one pair is applied also to the other, and the same structure is preferable by one pair.

In the forming apparatus 1 shown in FIG. 7, the glass plate Gs extruded from the forming roll 2 passes through the drawing roll through the slow cooling region by the slow cooling means, and then the cutting means, similarly to the forming apparatus 1 shown in FIG. It is cut by. About a slow cooling means, a drawing roll, and a cutting | disconnection means, it can carry out similarly to the shaping | molding apparatus 1 shown in FIG.

In the molding apparatus of the present invention, the appropriate surface temperature range of the molding roll is appropriately set depending on the type of glass used, the size of the molding roll, the interval between the molding rolls, the amount of molten glass stored, the peripheral speed of the molding roll, and the like. The The molding apparatus of the present invention has a thermometer that measures the temperature distribution of the molten glass in the reservoir, as in the molding apparatus shown in FIG. 7, and is based on the temperature distribution data of the molten glass measured by this thermometer. The control means is configured to control the temperature adjustment means, specifically, the temperature adjustment means including the refrigerant flow passage built in the axial direction of the forming roll and the internal heater whose output distribution is variable in the axial direction. Thus, the surface temperature of the forming roll can be well controlled within the range of the set surface temperature so that the forming temperature of the molten glass does not have a temperature distribution in the axial direction.

Next, in the molding apparatus of the present invention, the control means controls the temperature adjusting means based on the temperature distribution data of the molten glass measured by a thermometer that measures the temperature distribution of the molten glass in the reservoir. In addition, the temperature control means includes a refrigerant flow passage installed in the axial direction of the molding roll and a ring heater disposed on the outer peripheral surface in the vicinity of the end of the molding roll, or in addition to these, the shaft of the molding roll An example of an embodiment of the molding apparatus according to the present invention having a configuration including an internal heater mounted in a direction will be described with reference to FIGS. 12 to 14B.

The molding apparatus 1 shown in FIG. 12 is arranged in an upper space defined by a pair of molding rolls 2 and molding surfaces of the pair of molding rolls 2 to form a storage portion P for molten glass Gm. It has a pair of weirs 3 and a thermometer 9 for measuring the temperature distribution of the molten glass in the reservoir P. In addition, the pair of forming rolls 2 includes, as temperature adjusting means, a flow path for the refrigerant built in the axial direction of the forming roll 2 and a ring heater 30 disposed on the outer peripheral surface near the end of the forming roll 2. Have. Further, the molding apparatus 1 shown in FIG. 12 has control means (not shown) for controlling the refrigerant flow path and the ring heater 30 based on the temperature distribution data of the molten glass measured by the thermometer 9. A nozzle 5 through which the molten glass Gm flows is provided between the weirs 3. Although not shown in FIG. 12, on the lower side of the pair of forming rolls 2, for example, a slow cooling means, a drawing roll, and a cutting means are provided in this order in the same manner as shown in FIG. .

The molding apparatus 1 shown in FIG. 12 has a thermometer 9 that measures the temperature of the molten glass in the storage portion P, and the refrigerant flow path and the molding roll 2 in which the temperature adjusting means is built in the axial direction of the molding roll 2. 1 can be the same as that of the molding apparatus 1 shown in FIG. 1 except that the ring-shaped heater 30 is provided on the outer peripheral surface in the vicinity of the end portion. Moreover, the thermometer 9 can be the same as the thermometer 9 which the shaping | molding apparatus 1 shown in FIG. 7 has, and the temperature measurement of the molten glass in the storage part P can also be the same as demonstrated above.

A molding roll 2 included in the molding apparatus 1 shown in FIG. 12 is disposed on the outer peripheral surface near the end portion of the coolant flow path and the molding roll 2 that are built in the axial direction of the molding roll 2 as temperature adjusting means. A forming roll having a ring-shaped heater 30 and capable of temperature control with a deviation in the axial direction. The refrigerant flow path and the ring-shaped heater are controlled by control means provided outside the normal forming roll, based on the temperature distribution data of the molten glass measured by the thermometer. Specifically, the surface temperature of the forming roll is controlled so as to average the temperature distribution of the molten glass.

Specifically, as a forming roll capable of temperature control having a deviation in the axial direction, a flow path for refrigerant is provided along the axial direction at the center of the forming roll, and the ring heater 30 includes a pair of A configuration in which both ends of the forming roll 2 are disposed on the outer peripheral surface near the end portion so as to be in contact with the outer peripheral surface is preferable. The ring-shaped heater 30 is controlled by a control means so as to control the surface temperature of the forming roll 2 from the outer peripheral surface including the outer peripheral surface of the forming roll 2 with which the ring-shaped heater 30 contacts to a predetermined position inside. In the molding apparatus 1 shown in FIG. 12, by having such a ring-shaped heater 30, the surface temperature of the molding roll 2 has a deviation in the axial direction, that is, the end of the molding roll 2 has a high temperature and goes toward the center. Therefore, temperature control with a low temperature gradient becomes possible.

Specifically, when the molten glass Gm is supplied from one nozzle 5 to the central portion of the reservoir P as in the molding apparatus 1 shown in FIG. 12, the temperature distribution in the axial direction of the molten glass Gm in the reservoir P Takes a symmetrical mountain-shaped temperature distribution with the central position at which the molten glass Gm is intensively supplied from the nozzle 5 as an apex. Therefore, in order to average this, if the ring heater 30 is disposed on the outer peripheral surface in the vicinity of the end at each end of the pair of forming rolls 2, both ends are heated to a high temperature, and the central portion is affected. As a result, the temperature of the forming roll 2 becomes a low temperature, and a temperature distribution in a symmetrical valley shape with the center position at the bottom in the axial direction can be obtained.

Here, in the molding apparatus 1 shown in FIG. 12, the ring-shaped heater 30 has the inner end surface of the ring-shaped heater 30 positioned between the inner surface and the outer surface of the weir 3, and the outer end surface is the molding roll 2. And the outer diameter of the arrangement position of the ring heater 30 in the forming roll 2 is shortened by the total thickness (thickness × 2) of the ring heater 30, The forming roll 2 has no step between the surface where the ring heater 30 is disposed and the surface of the portion where the ring heater 30 is not disposed, that is, the outer peripheral surface.

When the ring heater is provided on the outer peripheral surface in the vicinity of the end of the forming roll 2, the position where the ring heater is disposed is preferably the above position, but is not limited to the above position. Depending on the size and surface condition of the ring-shaped heater, if the surface temperature of the forming roll 2 can be adjusted with deviation in the axial direction, the end face on the inner side of the ring-shaped heater is the weir 3 if necessary. The inner surface may be located on the inner side, or the outer surface of the weir 3 may be located on the outer side. Similarly, the outer end face may be located inside or outside the end face of the forming roll 2. In the present specification, the vicinity of the end of the forming roll 2 refers to the position from the end of the forming roll to 1/4 of the length of the forming roll. Furthermore, providing near the end does not necessarily mean providing the end. If necessary, it is provided so that the entire width can be accommodated in the region from the end of the forming roll to the inner side of the length of the forming roll.

Further, when the forming roll 2 has a ring heater on the outer periphery in the vicinity of its end, there may be a step between the portion where the ring heater is disposed and the portion where the ring heater is not disposed. And a range that does not hinder the holding of a predetermined distance between the pair of forming rolls 2.

The thickness of the ring-shaped heater 30 is designed within an appropriate range depending on the outer diameter of the molding roll 2, the size and arrangement of the refrigerant flow path 24 built in the molding roll 2, or the configuration of the ring-shaped heater 30 itself. Is done. Further, the width of the ring-shaped heater 30 indicated by the distance from the inner end surface to the outer end surface of the ring-shaped heater 30 is an appropriate range in consideration of the length of the forming roll 2 and the position where the weir 3 is disposed. Designed to.

Here, in the molding apparatus 1 shown in FIG. 12, the pair of molding rolls 2 have the same size, but the outer diameter of the molding roll 2 may be the same between the pair of molding rolls 2. There may be a difference in size. Even if the outer diameters of the pair of forming rolls 2 are different, the peripheral speeds are made constant. As a method of making the peripheral speed constant, a method using a driving device similar to the molding apparatus 1 shown in FIG. 1 can be applied. The outer diameter of the forming roll 2 can be reduced by reducing the thickness of the glass molded body by setting the outer diameter to a short outer diameter, but the refrigerant flow path 24 built in the forming roll 2 is not narrowed 30. The range of ˜200 mm is preferred, and 50˜100 mm is more preferred.

The length of the pair of forming rolls 2 may be the same as or different from each other, but at least the width of the pair of weirs 3 is added to the width of the glass plate Gs obtained by molding. It is essential to be longer than the length. In order to efficiently control the temperature, the length of the pair of forming rolls 2 is preferably 1 to 20 mm longer than the width of the sheet glass to be formed. The outer diameter and length of the pair of forming rolls 2 are preferably the same from the viewpoint of controlling the surface temperature.

Among the molding rolls 2 included in the molding apparatus 1 shown in FIG. 12, the molding roll 2 having a refrigerant flow path along the axial direction at the center of the molding roll 2 and having the ring-shaped heater 30 at the preferred position. A cross-sectional view of the forming roll 2C is shown in FIGS. 13A and 13B. 13A is a cross-sectional view of the forming roll 2C in the longitudinal direction, and FIG. 13B is a cross-sectional view of the forming roll 2C shown in FIG. 13A along a line YY along a plane orthogonal to the longitudinal direction.

The forming roll 2 </ b> C has a refrigerant flow path 24 disposed in the center in the axial direction, and has a substantially cylindrical roll body 20 having an outer diameter near both ends shorter than that of the center. The forming roll 2 </ b> C has a ring-shaped heater 30 on the outer peripheral surface of a portion where the outer diameter in the vicinity of both end portions of the roll body 20 is shorter than that of the central portion so as to contact the outer peripheral surface. The roll main body 20 has a coating layer 23 in which a peripheral surface formed concentrically on the outer peripheral surface of a portion not having the ring-shaped heater 30 is a glass molding surface. The ring-shaped heater 30 includes a heater main body 30a and a heater coating layer 30b formed concentrically on the outer peripheral surface of the heater main body 30a, and the outer peripheral surfaces of the roll main body 20 and the heater main body 30a that do not have the ring-shaped heater 30 are The covering layer 23 and the heater covering layer 30b are positioned so as not to be uneven. The outer peripheral surfaces of the roll main body 20 and the heater main body 30a preferably have no step in the diameter direction, but it can be said that there is practically no step within a range of ± 0.1 mm.

Further, the forming roll 2C has a tubular member 29 integrally formed at both ends of the roll body 20 so that the centers of the cross sections perpendicular to the roll body 20 and the axial direction coincide with each other. The tubular member 29 is normally connected to a drive device (not shown), and a straight line passing through the center of the roll body 20 from the tubular member 29 in the axial direction becomes the rotation axis X, and the tubular member 29 rotates to form the forming roll 2C. This is a mechanism that rotates as a whole.

In the forming roll 2C, a cylindrical hole is formed in the center of the roll body 20 along the axial direction so that one end is connected to the one tubular member 29 and the other end is closed. By further including an inner tube 27 having both ends opened on the inner side, a refrigerant flow channel 24 formed by the outer wall of the inner tube 27 and the inner wall of the roll body 20 and the inner wall of the inner tube 27 is formed. 24 is formed. Further, the inner tube 27 is continuously provided up to the inside of the tubular member 29. The diameter and length of the cylindrical hole that the roll body 20 has for forming the coolant flow path 24, the thickness of the inner tube 27, and the like can be the same as those of the forming roll 2A.

Here, the flow of the refrigerant flowing through the refrigerant flow path 24 is the same as the flow of the cooling water in the forming roll 2A shown in FIG. 5A. The refrigerant is repeatedly circulated by heat exchange outside the forming roll 2C and supplied again to the forming roll 2C. Further, the flow rate control of the refrigerant may be performed by providing a flow rate adjusting valve or the like in the circulation channel after heat exchange. In addition, the flow path 24 for refrigerant | coolants may be formed in the form which penetrates the roll main body 20 from one tubular member 29, and is connected to the other tubular member 29 as needed.

As the type of refrigerant, synthetic oil, water and the like can be mentioned, but water is preferable from the viewpoint of safety and environmental resistance. The flow rate of the refrigerant is adjusted by the size of the forming roll 2C, the set surface temperature, and the like. The refrigerant flow path 24 is preferably designed so that the variable range of the refrigerant flow rate can be widened. Here, in the forming roll 2C, the refrigerant flow path 24 controls the temperature, flow rate, and the like of the refrigerant according to the setting of the control means based on the temperature distribution data of the molten glass measured by the thermometer 9, It has the function of controlling the surface temperature of the forming roll 2C as a whole on average.

The surface temperature of the forming roll 2C used in the present invention shown in FIGS. 13A and 13B is controlled by a combination of the refrigerant flow path 24 and the ring heater 30 disposed on the outer peripheral surface near the end of the forming roll 2C. As a result, the mechanism for causing a deviation in the axial direction of the surface temperature of the forming roll 2 </ b> C is based on the action of the ring-shaped heater 30. Although the refrigerant flow path 24 can be configured to be capable of changing the temperature in the axial direction depending on the design, the ring heater 30 is usually superior in terms of efficiency and variability. The mechanism for causing the temperature deviation to be mainly performed by adjusting the output and arrangement position of the ring heater 30.

In the forming roll 2C, the ring-shaped heater 30 is connected to a power source capable of adjusting the output outside the forming roll 2C by a conducting wire 33A. The power source connected to each ring-shaped heater 30 outside the forming roll 2 </ b> C uses the refrigerant flow path 24 and the ring-shaped heater 30 based on the temperature distribution data of the molten glass Gm in the storage portion P measured by the thermometer 9. Controlled by control means for controlling. Specifically, the control means refers to each of the ring heaters while referring to the axial surface temperature distribution data of the forming roll measured by the thermometer 9 and the axial temperature distribution data of the molten glass Gm in the reservoir P. By changing the output from 0 to the maximum output value at the power source connected to 30, the temperature distribution of the surface temperature of the forming roll 2C is controlled so as to average the temperature distribution of the molten glass in the reservoir P. .
The method for measuring the surface temperature distribution in the axial direction of the forming roll 2C can be the same as in the case of the forming roll 2B shown in FIG. 9A.

In the forming roll 2C, the ring-shaped heater 30 is formed of a heater body 30a and a heater coating layer 30b. The heater covering layer 30b can be the same as the covering layer 23 in the forming roll 2A shown in FIG. The heater body 30a includes, for example, an inner ring member in which a heating wire is wound along the outer peripheral surface, and an outer ring member that is concentrically disposed so as to cover the entire outer peripheral surface of the inner ring member with the heating wire. Is done. In this configuration, both ends of the heating wire are connected to a conducting wire 33A that leads to an external power source. The output of the ring heater 30 can be adjusted by the winding density of the heating wire in the heater body 30a. When the output distribution is to be provided in the width direction of the ring heater 30, that is, the axial direction of the forming roll, the heating wire winding is performed. The linear density may be adjusted in the width direction.

The inner diameter of the inner ring member matches the inner diameter of the heater body 30a, and the outer diameter of the outer ring member matches the outer diameter of the heater body 30a. In addition, the thicknesses of the outer ring member and the inner ring member are appropriately adjusted in the range of the thickness of the heater body 30a, for example, according to the thickness of the heating wire, the winding density, and the like. In such a heater main body 30a, it is preferable that the inner ring member and the outer ring member are made of the same material as that of the roll main body 20 from the viewpoint of reducing distortion generated due to a difference in coefficient of thermal expansion, for example.

About the roll main body 20 in the forming roll 2C and the coating layer 23 covering the surface (outer peripheral surface), the roll main body 20 and the coating layer 23 in the forming roll 2A shown in FIG. 5A are preferable except that the shape is as described above. The same can be done including the embodiment. The thickness indicated by (outer diameter−inner diameter) / 2 of the roll body 20 is preferably 10 to 80 mm, more preferably 20 to 50 mm from the above viewpoint.

In the forming roll 2C, the roll body 20 may be formed of, for example, two layers of the center member 21 and the intermediate layer 22 as required, like the forming roll 2B shown in FIG. 9A. Moreover, the two layers of the roll main body 20 and the coating layer 23 may be formed by one layer without distinction. When the center member 21, the intermediate layer 22, and the covering layer 23 are configured, each layer may be configured by a plurality of layers. Moreover, you may have the flange 26 as needed.
Although the structure of the forming roll 2C has been specifically described in one unit, the description of one of the one pair is applied to the other, and the same structure is preferable in one pair.

Next, among the forming rolls 2 included in the forming apparatus 1 shown in FIG. 12, a refrigerant flow path is provided along the axial direction at the center of the forming roll 2, and the ring heater 30 is provided at the preferred position. 14A and 14B are sectional views of the forming roll 2 provided with an internal heater provided in the axial direction of the forming roll 2 as a forming roll 2D. 14A is a cross-sectional view of the forming roll 2D in the longitudinal direction, and FIG. 14B is a cross-sectional view of the forming roll 2D shown in FIG. 14A along a line YY along a plane orthogonal to the longitudinal direction.

The forming roll 2D has a configuration in which ring-shaped heaters 30 similar to the forming roll 2C shown in FIGS. 13A and 13B are provided in the vicinity of both ends of the forming roll 2A shown in FIGS. 5A and 5B. About each component, it can carry out similarly including what was demonstrated with 2 A of forming rolls, or 2 C of forming rolls. Thus, it becomes easier to control the surface temperature of the molding roll 2D to a desired temperature by combining a plurality of temperature adjusting means.

Here, in the molding apparatus 1 shown in FIG. 12, the glass plate Gs extruded from the molding roll 2 passes through the drawing roll through the slow cooling region by the slow cooling means, as in the molding apparatus 1 shown in FIG. It is cut by the cutting means. About a slow cooling means, a drawing roll, and a cutting | disconnection means, it can carry out similarly to the shaping | molding apparatus 1 shown in FIG.

In the molding apparatus of the present invention, the appropriate surface temperature range of the molding roll is appropriately set depending on the type of glass used, the size of the molding roll, the interval between the molding rolls, the amount of molten glass stored, the peripheral speed of the molding roll, and the like. The In the shaping | molding apparatus of this invention, it has a thermometer which measures the temperature distribution of the molten glass in a storage part like the shaping | molding apparatus shown in FIG. 12, Based on the temperature distribution data of the molten glass measured by this thermometer The control means includes a temperature adjusting means, specifically, a refrigerant flow passage installed in the axial direction of the forming roll and a ring heater disposed on the outer peripheral surface near the end of the forming roll, or In addition to these, by controlling the temperature adjusting means provided with an internal heater built in the axial direction of the forming roll, the surface temperature of the forming roll is adjusted within the range of the set surface temperature, and the molten glass is formed. The temperature can be well controlled so as not to have a temperature distribution in the axial direction.

In the molding apparatus of the present invention, in addition to the temperature adjusting means described above, temperature adjusting means acting from the outside of the forming roll may be additionally provided. As such a thing, the ventilation means which blows cold air or warm air to the surface from the exterior of a forming roll, or the heat medium contact means which contacts a heat medium directly or indirectly is mentioned, for example. Moreover, heating means, such as an infrared heating means, a gas combustion heating means, and an induction heating means, may be used. By additionally controlling the surface temperature by such an external temperature adjusting means, the surface temperature of the forming roll can be controlled more appropriately.

As an example of a molding apparatus having a temperature adjusting means for cooling or heating the surface of the molding roll from the outside, specifically, near both ends of the molding roll such as the molding roll 2A shown in FIG. 5A or the molding roll 2B shown in FIG. 9A. And a gas combustion heating means such as a Bunsen burner or a line burner provided as a temperature adjusting means at a position where the outer peripheral surface of the steel can be heated. In this case, the arrangement position of the gas combustion heating means is, for example, the surface portion in the vicinity of the end of the forming roll 2 on the opposite side to the forming point Z where the pair of forming rolls 2 shown in FIG. A position where heating is possible is preferred. Here, as the vicinity of the end of the forming roll, a region similar to the region where the ring heater is provided in the above is preferable. When the gas combustion heating means is used as the temperature adjusting means, the gas combustion heating means is controlled by a gas supply amount adjusting valve or the like, or by adjusting the distance between the gas combustion heating means and the forming roll.
Further, finer temperature control can be expected by arranging a gas combustion heating means with a large output near the end and a gas combustion heating means with a small output near the center as required.

[Glass forming method]
The glass molding method of the present invention comprises a molten glass, preferably a molten glass having a viscosity of 0.01 to 100 dPa · s, between a pair of molding rolls whose rotational axes are arranged in parallel with each other at a predetermined interval. And forming the glass by controlling the surface temperature of the pair of forming rolls and forming the upper side space section defined by the forming surfaces of the pair of forming rolls. A pair of molten glass damming members are arranged at intervals in the axial direction of the forming roll, and the molten glass is stored between the molten glass damming members.

In the glass molding method of the present invention, the control of the surface temperature of the pair of molding rolls is to measure the temperature distribution of the stored molten glass, and to obtain the temperature distribution data of the molten glass obtained by the measurement. Based on this, the temperature distribution is preferably averaged.

As described above, the glass molding method of the present invention is suitably used for molding a low-viscosity molten glass having a viscosity of 0.01 to 100 dPa · s. In particular, the relationship between temperature and viscosity in the molten glass is steep, It is preferably used in the case of glass having a very low viscosity from the molten state to just before solidification. In the glass molding method of the present invention, for example, the molten glass is supplied using the molding device 1 so that the molten glass is uniform in the axial direction of the molding roll when passing between the molding rolls. Corresponding to the temperature of the molten glass, preferably the surface temperature of the molding roll is controlled appropriately based on the temperature distribution of the molten glass measured by a thermometer, specifically, the temperature distribution of the molten glass By controlling to average, in the rollout method, it is possible to form the low-viscosity molten glass with uniform size and quality such as plate width and plate thickness while suppressing striae and distortion. It was.

Hereinafter, an embodiment using the molding apparatus 1 shown in FIG. 1 will be described for the glass molding method of the present invention. The glass forming method of the present invention is not limited to the following embodiment.
As the glass, phosphate glass, borate glass, or fluorophosphate glass is preferably used, and these are heated to about 900 ° C. to obtain molten glass Gm. The viscosity of the molten glass Gm is preferably 0.01 to 100 dPa · s, and more preferably 0.1 to 100 dPa · s. This molten glass Gm flows down from the nozzle 5 to the weir 3. Hereinafter, a specific shaping | molding method is demonstrated to the case where the phosphate glass, borate glass, or fluorophosphate glass is used as glass.

In the molten glass Gm, as shown in FIG. 3, the width between the surfaces of the forming rolls 2 on the upper surface of the storage made of molten glass Gm, that is, the storage width W of the upper surface of the molten glass Gm in the storage portion P is 2 to 40 mm. It is preferable to store up to. The storage width W is more preferably 5 to 15 mm. By storing the molten glass Gm up to such a position, the contact time with the forming roll 2 can be lengthened, and it can be sufficiently cooled and solidified. Although the molten glass Gm may be stored up to a position higher than the above position, the molten glass Gm is usually set up to the position of the upper end of one of the pair of forming rolls 2. In addition, although the storage amount of the molten glass Gm may fluctuate during shaping | molding, it is preferable to hold | maintain the said position at least. The storage amount of the molten glass Gm can be adjusted by changing the flow rate of the molten glass Gm from the nozzle 5 and the molding speed, but it is preferable that the molten glass Gm does not vary at least during continuous molding. Further, the distance L between the pair of weirs 3, that is, the storage length of the molten glass Gm in the storage part P is preferably 100 to 300 mm.

The molten glass Gm supplied between the weirs 3 spreads in the axial direction of the forming roll 2 and is stored in the entire area between the weirs 3, and is gradually cooled on the surface of the forming roll 2. It passes through the forming roll 2 and is formed into a glass plate Gs.

The forming roll 2 can reduce the thickness of the glass plate Gs as the outer diameter is reduced. However, it is preferable that the forming roll 2 has a certain outer diameter from the viewpoint of interior of the refrigerant flow path and the internal heater, for example, 30 to 200 mm. preferable. The gap S between the forming rolls 2 is preferably 0 to 2 mm, although it depends on the required thickness T of the glass plate Gs.

In addition, since the adjustment of the gap S between the forming rolls 2 is performed by an air cylinder or the like, the thickness T of the glass plate Gs is not necessarily the same thickness as the gap S between the forming rolls 2. If the rotation speed of the forming roll 2 is slow, the plate thickness T of the glass plate Gs is thicker than the gap S, and if the rotation speed is high, the plate thickness T of the glass plate Gs is the same thickness as the gap S. A preferable rotation speed is a rotation speed at which the thickness T and the gap S of the glass plate Gs are the same. From such a viewpoint, the peripheral speed of the pair of forming rolls 2 is preferably 300 to 2000 mm / min, and more preferably 800 to 1500 mm / min. The surface temperature of the forming roll is controlled in the range of 250 to 700 ° C., preferably in the range of 280 to 480 ° C.

The glass sheet Gs discharged from the pair of forming rolls 2 moves to the lower side so as to be pulled by the pair of drawing rolls 7 through the slow cooling means 6. In this way, by passing the slow cooling means 6 while pulling by the draw roll 7, it is possible to gradually cool and suppress the generation of cracks, and to obtain a plate-like shape. The peripheral speed of the drawing roll 7 is preferably 3 to 20% higher than the forming roll speed. The glass plate Gs that has passed through the drawing roll 7 is cut by the cutting means 8 to be a short glass plate Gs. Thereafter, surface polishing or the like is performed as necessary to obtain a final product.

In the glass molding method of the present invention, the surface temperature of a pair of molding rolls is measured, the temperature distribution of the stored molten glass is measured, and this temperature is determined based on the temperature distribution data of the molten glass obtained by the measurement. A case where the distribution is averaged will be described with an embodiment using the molding apparatus 1 shown in FIG. 7 or 12 as an example.

When the molding apparatus 1 shown in FIG. 7 or FIG. 12 is used, the temperature distribution of the molten glass stored in the storage unit is measured by the thermometer 9, and this temperature is determined based on the measured temperature distribution data of the molten glass. The surface temperature of the pair of forming rolls is controlled so as to average the distribution.

Specifically, the control of the surface temperature of the forming roll 2 is performed by the refrigerant flow path 24 provided in the forming roll 2 provided as temperature adjusting means along the axial direction and the internal heater whose output distribution is variable in the axial direction. 25 is performed by a control means provided for controlling.
Further, instead of the refrigerant flow path 24 and the internal heater 25 whose output distribution is variable in the axial direction, as the temperature adjusting means, the refrigerant flow path 24 built in the axial direction of the forming roll and the vicinity of the end of the forming roll. The surface temperature of the forming roll 2 is controlled even when the ring-shaped heater 30 disposed on the outer peripheral surface of the forming roll 2 is provided or when the internal heater 25 is provided in the axial direction of the forming roll. This is performed by control means provided for controlling the temperature adjusting means.

Further, as the temperature adjusting means, in addition to the temperature adjusting means, a temperature adjusting means acting from the outside of the forming roll, for example, a blowing means for blowing cool air or hot air from the outside of the forming roll to the surface thereof, or heat A heating medium contact means for directly or indirectly contacting the medium, a heating means such as an infrared heating means, a gas combustion heating means, an induction heating means or the like may be used. By additionally controlling the surface temperature by such temperature adjusting means from the outside of the forming roll, the surface temperature of the forming roll can be controlled more appropriately.

In a preferable molding method of the present invention, the control means controls the temperature adjusting means based on the temperature distribution data of the molten glass measured as described above, so that the temperature distribution of the molten glass is averaged. Thus, the surface temperature of the forming roll 2 is controlled.

The present invention is not limited to the description of the embodiment described above, and it goes without saying that changes and modifications can be made as appropriate without departing from the gist of the present invention.

Hereinafter, specific description will be given with reference to examples.
Example 1
As the molding apparatus 1, the one shown in FIG. 1 was prepared. Each of the pair of forming rolls 2 is made of chromium copper, has an outer diameter of 100 mm, a width of 200 mm, and is provided with temperature adjusting means 4 including a coolant channel 24 and an internal heater 25 for circulating cooling water therein, and has a surface temperature of 280. Adjusted to ° C. The refrigerant flow path 24 and the internal heater 25 were designed and arranged in the same manner as in Example 5 below. The pair of forming rolls 2 were arranged in parallel to each other so that the interval between the forming surfaces was 1 mm, and the peripheral speed was 1000 mm / min.

The pair of weirs 3 were arranged with an interval of 180 mm in the axial direction of the forming roll 2. Each weir 3 was manufactured by processing a heat insulating board (manufactured by NICHIAS Corporation, trade name MD16) into a substantially inverted triangular shape as shown in FIG. Here, each weir 3 has a thickness of 10 mm, a lower end position (distance L1) of 5 mm, and an upper position (distance L2) of 45 mm. In addition, the curved surface portion was formed from the position of the lower end portion of the weir 3 to the upper position so that it was at least 0.5 mm from the surface of the forming roll 2.

The slow cooling device 6 was provided from the lower end of the forming roll 2 in the vertical direction from a position of 100 mm to a position of 500 mm, the inlet side temperature was 400 ° C., and the outlet side temperature was 250 ° C. In the drawing roll 7, the surface of a core material 71 made of stainless steel or the like was coated with a 10 mm thick intermediate covering layer 72 made of PBO fiber felt and a 1 mm thick surface protective layer 73 made of silica cloth.

Then, a fluorophosphate glass heated to about 900 ° C. as a molten glass Gm having a viscosity of 0.01 to 100 dPa · s was caused to flow from a circular nozzle 5 having an inner diameter of 5 mm at a rate of 30 kg / hour. As a result, the molten glass Gm spreads in the axial direction of the forming roll 2 and was stored in the entire area between the weirs 3 and passed through the pair of forming rolls 2 and formed into a glass plate Gs. It was recognized that the molded glass plate Gs was continuous in the width direction and also suppressed the occurrence of striae and distortion due to volatilization loss. In addition, the width W of the upper surface of the molten glass Gm in the storage part at the time of shaping | molding was about 10 mm, the width | variety of the obtained glass plate Gs was 180 mm, plate | board thickness was 1 mm, and plate | board thickness deviation was 0.1 mm.

(Example 2)
Except for changing the constituent material of the weir 3, molding was performed using the same molding apparatus 1 as in Example 1, and the releasability and cracking of the weir 3 were evaluated. Here, since the constituent material of the weir 3 needs to have the same concave shape as the roll radius curvature, machinable ceramics and inorganic compacts that can be machined were selected. Specifically, ceramics (sintered body) of aluminum nitride, boron nitride, and aluminum titanate, glass fiber laminated board Rosna board (trade name, manufactured by Nikko Kasei Co., Ltd.), inorganic powder molded body Nicoseram, Thermobarrier 800, Thermobarrier 1000 (manufactured by Nikko Kasei Co., Ltd., trade name) and inorganic fiber molded product MD16 (trade name, manufactured by NICHIAS Corporation).

The results are shown in Table 1. The releasability is determined by visually observing the surface of the weir 3 after molding. “◎” indicates that there is almost no adhesion on the contact surface with the molten glass Gm, and “◯” indicates that the adhesion is slightly. The case where the adhesion was about half of the contact surface was indicated by “Δ”, and the case where the adhesion was substantially on the entire contact surface was indicated by “x”. In addition, the damage due to strength deterioration is defined as cracking, and the weir 3 after molding is visually observed. “O” indicates that there is no large crack, and “B” indicates that there is a large crack that can be divided in half. X.

Although any component material could be molded, it has good releasability and is less susceptible to cracking. As a component material, especially inorganic powder molded product Rosna board (Nikko Kasei Co., Ltd.) It is understood that a ceramic sintered body made by company, trade name) or boron nitride is preferable.

(Examples 3 and 4)
A molding apparatus 1 similar to that of Example 1 is prepared except that the temperature adjusting unit 4 is changed to a cooling heating unit that circulates a heat medium made of high-temperature synthetic oil and performs both cooling and heating (Example 3). ). In addition to the cooling and heating means, a discharge valve and forced discharge means (by compressed air) are provided in the circulation path, and the discharge is performed by a measuring means for measuring the temperature of the heat medium and an abnormal signal from the measuring means. A molding apparatus 1 similar to that in Example 3 is prepared except that an emergency discharge system including an automatic unit that automatically drives the valve and the forced discharge unit is provided (Example 4). As synthetic oil, Barrel Therm 400 (manufactured by Matsumura Oil Co., Ltd., trade name) is used.

Using these molding apparatuses 1, molding is performed under the same conditions as in Example 1, and the circulation of the heat medium is stopped for 30 seconds during the process, and the state is observed. As a result, in the molding apparatus 1 of Example 3, the heat medium in the molding roll 2 becomes a high temperature, and a large amount of white smoke is generated due to the decomposition of the heat medium. On the other hand, in the molding apparatus 1 according to the fourth embodiment, the automation unit functions in response to the abnormal signal from the measurement unit, and the heat medium in the molding roll 2 is discharged from the discharge valve by the forced discharge unit. Generation of white smoke can be suppressed.

(Comparative Example 1)
In the molding apparatus 1 shown in FIG. 1, molding was performed under the same conditions as in Example 1 except that the internal heater 25 in the molding roll was not used. As a result, the surface temperature was normal at the start of molding, and the molded glass plate GS had irregularities of several millimeters called chill ripples on the surface. Thereafter, the surface temperature was raised to 200 ° C., and fine cracks parallel to the roll width direction called cold cracks were generated on the surface. Furthermore, when the surface temperature reached 280 ° C., the surface of the glass plate GS was flattened and a good sample could be obtained, but by that time a large number of defective products had occurred. . As the molding continued, the surface temperature continued to rise and the product acquisition time continued. However, the molding roll and the glass plate GS started to partially adhere around the surface temperature exceeding 480 ° C, and finally the molding was continued due to the entire adhesion. Became impossible. During this time, even if the amount of roll cooling water was adjusted, the amount of heat exchange could not be varied greatly, so the surface temperature could not be optimized.

(Comparative Example 2)
In the molding apparatus 1 shown in FIG. 1, molding was performed under the same conditions as in Example 1 except that no weir 3 was provided in the axial direction of the molding roll. As a result, the fluorophosphate glass that flowed down from the single tubular nozzle spread in the axial direction of the forming roll, but the spreading method becomes unstable due to the wettability of the glass substrate to the surface of the forming roll and the time fluctuation of the flowing substrate, As a result, the plate width of the formed glass plate was 200 mm or more, and not only the plate thickness could not be uniformly stabilized but also changed periodically, so that it was not possible to obtain a product with a constant plate width.

(Comparative Example 3)
In Examples 3 and 4, when the cooling and heating circuit that circulates the heat medium and performs both cooling and heating is temporarily stopped, the roll temperature rises due to heat input from the glass GS and stays in the roll. It was confirmed that the temperature of the heat medium was raised to the vicinity of the thermal decomposition temperature, which was not preferable for safety.

(Example 5)
As the molding apparatus 1, the one shown in FIG. 7 was prepared. In addition, the shaping | molding roll was comprised by what is shown to FIG. 9A and 9B. Further, the cartridge heaters incorporated in the forming rolls were the two types of cartridge heaters shown in FIGS. 10A and 10B.
The pair of forming rolls 2 are made of SUS304 having an outer diameter of 100 mm and a length of 200 mm, and a Young's modulus of 210 GPa (the following thermal conductivity at a forming roll surface temperature of 280 ° C. is 18 W / m · K). Is 18 mm, outer diameter is 40 mm, Young's modulus is 80 GPa, and the intermediate layer 22 made of chromium copper (the following thermal conductivity at a forming roll surface temperature of 280 ° C. is 280 W / m · K) is 30 mm, The layer thickness of the Ni—B—W alloy plating layer was 0.015 mm.

One end of the central member 21 is closed and the other end is open, and the inner end of the central member 21 from the opened end has an inner diameter of 6 mm, an outer diameter of 10 mm, and a length of 600 mm (200 mm of which includes a flange) Part) is formed, and a refrigerant flow path 24 through which water flows as a refrigerant is formed. In addition, a pair of disk-shaped flanges 26 having a thickness of 20 mm are disposed so as to cover the end portion of the intermediate layer 22 and contact the central member 21 at the central portion. The center member 21 is integrally formed. The material of the flange 26 was the same as that of the central member 21.

In the following glass molding, water for cooling was circulated at a flow rate of 8 L / min at an inlet water temperature of 20 ° C. The intermediate layer 22 has a cartridge heater 25B that is concentrically centered about the central member 21 and has an output uniform power of 700 W / 200 mm along the axial direction, and a cartridge having an output deviation of 700 W / 200 mm to 1400 W / 200 mm. A total of 12 cartridge heaters were arranged by alternately attaching 6 heaters 25A to the flange 26.

Here, as for the winding density of the heating wire 32 of the cartridge heater 25A, when the winding density of the heating wire 32 of the cartridge heater 25B is 100%, 1/3 of the central portion is 100% winding density and both end portions Was adjusted so that the winding density was 150%.
At this time, the cartridge heaters 25A and 25B are arranged such that there is no gap between the adjacent isosceles triangles when a virtual isosceles triangle is drawn with the central portion as the apex of the apex angle. . The apex angle at this time was 60 degrees, and the isosceles triangle was a regular triangle. The distance of the cartridge heater 25 from the surface of the molding roll 2 was 10 mm.
Thereby, the surface temperature of the forming roll 2 was adjusted to 280 ° C. Further, the pair of forming rolls 2 were arranged in parallel with an interval of 1 mm, and the peripheral speed was 1000 mm / min.

The pair of weirs 3 were arranged with an interval of 180 mm in the width direction of the forming roll 2 and had a substantially inverted triangular shape as shown in FIG. Each weir 3 was manufactured by processing a fiber-based heat insulation board MD16 (manufactured by NICHIAS Corporation, trade name). More specifically, the shape of each weir 3 is 10 mm in thickness, 40 mm in height from the bottom to the top of the inverted triangle, and is in a shape in sliding contact with the pair of forming rolls 2.

The slow cooling means 6 was provided from the lower end of the forming roll 2 in the vertical direction from 100 mm to 800 mm, the inlet side temperature was 500 ° C., and the outlet side temperature was 200 ° C. In the drawing roll 7, the surface of a core material having a diameter of 80 mm made of stainless steel or the like was coated with a 10 mm thick intermediate coating layer made of PBO fiber felt and a 2 mm thick surface protective layer made of silica cloth. The peripheral speed of the drawing roll 7 was 1100 mm / min.

Then, fluorophosphate glass heated to about 900 ° C. as molten glass Gm having a viscosity of 10 dPa · s was caused to flow down at a rate of 30 kg / hour from a single tubular nozzle 5 having an inner diameter of 5 mm. As a result, the molten glass Gm spread in the width direction and was stored between the pair of weirs 3 and was formed by passing through the pair of forming rolls 2. It was recognized that the molded glass plate Gs was continuous in the width direction and also suppressed the occurrence of striae and distortion due to volatilization loss.

It should be noted that the cartridge heater 25A group and the cartridge heater 25B group are averaged so as to average the difference between the temperature m2 in the central portion in the axial direction of the molten glass Gm and the temperature m1 in the vicinity of the weir 3 in the storage portion P at the time of molding shown in FIG. When the surface temperature of the forming roll 2 was adjusted while changing the output from 0 to the maximum output value, the relationship of averaging the temperature distribution in the axial direction of the molten glass Gm was obtained, and the molding fluctuation in the axial direction as described above. Molding is possible in a situation where there is little.

(Example 6)
As the molding apparatus 1, the one shown in FIG. 12 was prepared. The forming rolls were configured as shown in FIGS. 14A and 4B. Further, the cartridge heater incorporated in the forming roll is the cartridge heater 25B shown in FIG. 10B, which is the same as the cartridge heater 25B used in Example 5.
The pair of forming rolls 2 has an outer diameter of 100 mm, a length of 200 mm, and a roll body 20 made of chromium copper having a Young's modulus of 80 GPa (the following heat conductivity at a forming roll surface temperature of 280 ° C. is 280 W / m · K). The layer thickness was 30 mm, and the thickness of the Ni—B—W alloy plating layer as the coating layer 23 was 0.015 mm.

In the pair of forming rolls 2, the roll body 20 has a ring-shaped heater 30 having a width of 30 mm and a thickness of 10 mm on the outer peripheral surface in the vicinity of both ends, and the pair of roll bodies 20 has a ring-shaped heater from both ends to the inside. The shape was smaller by 30 width and thickness. The ring-shaped heater 30 was disposed such that the outer end surface thereof coincided with the end surface of the roll body 20, and there was no step on the outer peripheral surface of the forming roll 2.

The ring-shaped heater 30 was composed of a heater coating layer 30b and a heater body 30a, and the heater coating layer 30b was a Ni—B—W alloy plating layer having a thickness of 0.015 mm. The heater main body 30a has a heating wire 32 wound around the outer peripheral surface thereof, and both ends of the heating wire 32 are connected to a power source capable of adjusting output through a conducting wire.

The roll body 20 is formed with a cylindrical hole (diameter 20 mm, length 190 mm) having one end closed in the central axis direction and the other end opened, and a tubular member 29 integrally formed at both ends of the roll body 20. An open end is connected to one of the inner ends of the cylindrical member 29 from the end opened through the inside of the tubular member 29. The inner diameter is 6 mm, the outer diameter is 10 mm, and the length is 600 mm (of which 180 mm is the roll body). A pipe 27 is provided to form a refrigerant flow path 24 through which water flows as a refrigerant.

In addition, twelve of the cartridge heaters 25B are arranged at the same positions as the cartridge heaters 25B and 25A arranged alternately in the fifth embodiment, and both ends of the heating wire 32 are connected via conductors like the ring heater. Connected to a power supply with adjustable output. In the following glass molding, cooling water was circulated at a flow rate of 8 L / min at an inlet water temperature of 20 ° C. The surface temperature of the molding roll 2 was adjusted to 280 ° C. by adjusting the outputs of the cartridge heater 25B and the ring heater 30. Further, the pair of forming rolls 2 were arranged in parallel with an interval of 1 mm, and the peripheral speed was 1000 mm / min.

The pair of weirs 3, the slow cooling means 6, and the drawing roll 7 were the same as in Example 5. A fluorophosphate glass heated to about 900 ° C. as a molten glass Gm having a viscosity of 10 dPa · s was caused to flow through the molding apparatus 1 at a rate of 30 kg / hour from a single tubular nozzle 5 having an inner diameter of 5 mm. As a result, the molten glass Gm spread in the width direction and was stored between the pair of weirs 3 and was formed by passing through the pair of forming rolls 2. It was recognized that the molded glass plate Gs was continuous in the width direction and also suppressed the occurrence of striae and distortion due to volatilization loss.

Note that the outputs of the cartridge heater 25B and the ring heater 30 are averaged so as to average the difference between the temperature m2 in the central portion in the axial direction of the molten glass Gm and the temperature m1 in the vicinity of the weir 3 in the storage portion P during molding shown in FIG. When the surface temperature of the forming roll 2 was adjusted while changing the value from 0 to the maximum output value, the relationship of averaging the temperature distribution in the axial direction of the molten glass Gm was obtained, and as described above, there was a change in the forming variation in the axial direction. Molding in fewer situations became possible.

(Example 7)
In the molding apparatus used in Example 6, a molding roll similar to that used in Example 1 was used as the molding roll, and a Bunsen burner was provided at a position where the outer peripheral surfaces near both ends of the molding roll could be heated. Then, the fluorophosphate glass was molded.
As the Bunsen burner, a 7.7 kW Bunsen burner manufactured by Takamitsu Industries was used. The Bunsen burner was disposed at a position where the surface portion near the end of the forming roll 2 on the opposite side to the forming point Z at which the pair of forming rolls 2 shown in FIG. In addition, the heating range by a Bunsen burner was the range from the edge part of a forming roll to the inner side 30mm. Two Bunsen burners were attached to one molding roll, and two were prepared near both ends.

In this molding apparatus, fluorophosphate glass heated to about 900 ° C. as molten glass Gm having a viscosity of 10 dPa · s was caused to flow from a single tubular nozzle 5 having an inner diameter of 5 mm at a rate of 30 kg / hour. As a result, the molten glass Gm spread in the width direction and was stored between the pair of weirs 3 and was formed by passing through the pair of forming rolls 2. It was recognized that the molded glass plate Gs was continuous in the width direction and also suppressed the occurrence of striae and distortion due to volatilization loss.

In addition, the outputs of the cartridge heater 25B and the Bunsen burner are set to 0 so that the difference between the temperature m2 in the central portion in the axial direction of the molten glass Gm and the temperature m1 in the vicinity of the weir 3 in the storage portion P at the time of molding shown in FIG. When the surface temperature of the forming roll 2 was adjusted while changing from the maximum output value to the maximum output value, the relationship of averaging the temperature distribution in the axial direction of the molten glass Gm was obtained, and there was little molding variation in the axial direction as described above It became possible to mold with. Further, when the surface temperature of the forming roll 2 was adjusted while appropriately moving the installation position of the Bunsen burner to an arbitrary position inside, a relationship for averaging the temperature distribution in the axial direction of the molten glass Gm was obtained, As described above, molding can be performed in a state where there is little molding variation in the axial direction.

The glass forming apparatus of the present invention is limited to high spatial frequency components of subject light in molten glass, particularly low-viscosity molten glass, for example, a solid-state imaging device such as a CCD or CMOS, and the light from the subject accompanying generation of a pseudo signal. It is suitably used for the production of a glass plate for an optical low-pass filter that removes different color light components. Moreover, it is suitably used for the production of substrate glass for bonding in color filters of video cameras and digital cameras, and MEMS (Micro Electro Mechanical Systems).

DESCRIPTION OF SYMBOLS 1 ... Molding apparatus 2, 2A, 2B, 2C, 2D ... Molding roll, 3 ... Molten glass weir member (weir), 4 ... Temperature adjustment means, 5 ... Nozzle, 6 ... Slow cooling means, 7 ... Draw roll, 8 ... Cutting means, 9 ... Molten glass temperature measuring means (thermometer)
DESCRIPTION OF SYMBOLS 20 ... Roll main body, 21 ... Center member, 22 ... Intermediate layer, 23 ... Cover layer, 24 ... Refrigerant flow path, 25 ... Internal heater, 25A ... Output deviation heater, 25B ... Output uniform heater, 26 ... Flange, 27 ... Inner tube, 29 ... tubular member, 30 ... ring-shaped heater, 30a ... heater body, 30b ... heater coating layer 31 ... outer cylinder, 32 ... heating wire, 33, 33A, 33a, 33b ... conductor, 34 ... core Gm ... melting Glass, Gs ... Glass plate, X ... Rotating shaft, Z ... Forming point, S ... Gap between forming rolls, T ... Glass plate thickness P ... Molten glass reservoir, L ... Interval of molten glass weir member (of reservoir) Length), L1 ... distance between the forming point and the lower end of the weir, L2 ... distance in the vertical direction between the forming point and the center of the forming roll and the upper part of the weir, W ... width of the upper surface of the reservoir.

Claims (22)

1. A glass forming apparatus used for forming molten glass,
   A pair of forming rolls whose rotational axes are arranged in parallel with each other at a predetermined interval;
   A pair of upper space portions defined by the molding surfaces of the pair of forming rolls are spaced apart from each other in the axial direction of the forming rolls, and the molten glass reservoir is formed in the upper space portion. A molten glass damming member;
   Temperature adjusting means disposed at least inside the pair of forming rolls;
   And a control unit that controls a temperature adjusting unit so as to control a surface temperature of the pair of forming rolls.
2. Furthermore, it has a molten glass temperature measuring means for measuring the temperature distribution of the molten glass in the storage section, and the temperature adjusting means is provided in the axial direction of the forming roll, and is provided with a refrigerant flow path and an axial output distribution. The glass forming apparatus according to claim 1, further comprising: a variable internal heater, wherein the control unit controls the temperature adjusting unit based on temperature distribution data of the molten glass measured by the measuring unit.
3. In the molding roll, the refrigerant flow path is disposed along the axial direction at the center of the molding roll, and a plurality of the internal heaters are disposed concentrically outside the refrigerant flow path, The glass forming apparatus according to claim 2, wherein at least one of the internal heaters is an internal heater having a different output distribution in the axial direction.
4. In the cross section perpendicular to the rotation axis of the forming roll, the other two vertices of an imaginary isosceles triangle whose apex is the vertex of the inner heater is in contact with and adjacent to the outer periphery of the forming roll. A forming roll in which internal heaters having different output distributions in the axial direction and internal heaters having uniform output in the axial direction are alternately arranged so that the vertices on the outer periphery of the forming roll of the isosceles triangle overlap. The glass forming apparatus according to claim 3, wherein the apex angle of the equilateral triangle is in the range of 40 to 80 degrees.
5. Furthermore, it has a molten glass temperature measuring means for measuring the temperature distribution of the molten glass in the storage section, and the temperature adjusting means is disposed in the axial direction of the forming roll and in the vicinity of the end of the forming roll. 2. The glass molding according to claim 1, further comprising a ring-shaped heater disposed on an outer peripheral surface of the glass, wherein the control unit controls the temperature adjusting unit based on temperature distribution data of the molten glass measured by the measuring unit. apparatus.
6. 6. The glass forming apparatus according to claim 5, wherein the temperature adjusting means further includes an internal heater built in the axial direction of the forming roll.
7. The glass forming apparatus according to any one of claims 1 to 6, wherein a viscosity of the molten glass is 0.01 to 100 dPa · s.
8. The molten glass damming member has a curved surface portion that is in sliding contact with the forming roll, or has a curved portion that is disposed with a gap that does not leak from the forming roll. The glass forming apparatus according to item.
9. The glass forming apparatus according to any one of claims 1 to 8, wherein a lower end portion of the molten glass damming member is provided up to a position where a distance L1 from a forming point of the pair of forming rolls is 0 to 5 mm. .
10. The upper part of the molten glass damming member is provided such that the uppermost position of the pair of forming rolls is at a position higher by 9/10 or more of the radius of the forming roll from the center of the lower forming roll. Item 10. The glass forming apparatus according to any one of Items 1 to 9.
11. The glass forming apparatus according to any one of claims 1 to 10, wherein the pair of molten glass damming members are made of a composite material in which heat resistant fibers are combined or a ceramic sintered body.
12. The glass forming apparatus according to any one of claims 1 to 11, wherein the molten glass is disposed so as to flow down from one or a plurality of nozzles to the storage section.
13. The glass forming apparatus according to any one of claims 1 to 12, wherein the molten glass is phosphate glass, borate glass, or fluorophosphate glass.
14. The glass forming apparatus according to any one of claims 1 to 13, wherein the pair of forming rolls has a peripheral speed of 300 to 2000 mm / min during forming.
15. The glass forming apparatus according to any one of claims 1 to 14, wherein the pair of forming rolls has a surface temperature of 250 to 700 ° C during forming.
16. A glass molding method in which molten glass is introduced between a pair of molding rolls whose rotational axes are arranged in parallel with each other at a predetermined interval, and molding is performed.
    In the molding, the surface temperature of the pair of molding rolls is controlled, and a pair of the pair of molding rolls is spaced apart in the axial direction of the molding roll in the upper space defined by the molding surfaces of the pair of molding rolls. A glass forming method, comprising: arranging a molten glass damming member and storing the molten glass between the molten glass damming members.
17. The control of the surface temperature of the pair of forming rolls measures the temperature distribution of the stored molten glass, and averages the temperature distribution based on the temperature distribution data of the molten glass obtained by the measurement. The glass forming method according to claim 16, wherein
18. The glass forming method according to claim 16 or 17, wherein the viscosity of the molten glass is 0.01 to 100 dPa · s.
19. The glass forming method according to any one of claims 16 to 18, wherein the storage is performed by setting a width W between the forming surfaces on the upper surface of the storage made of molten glass to be 2 to 40 mm.
20. The glass molding method according to any one of claims 16 to 19, wherein the molten glass is phosphate glass, borate glass, or fluorophosphate glass.
21. The glass forming method according to any one of claims 16 to 20, wherein the surface temperature of the pair of forming rolls is controlled within a range of 250 to 700 ° C.
22. The glass forming method according to any one of claims 16 to 21, wherein the peripheral speed of the pair of forming rolls is 300 to 2000 mm / min.

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