WO2013164964A1

WO2013164964A1 - Sound wave levitation device, sound wave levitation method, plate glass manufacturing apparatus, and plate glass manufacturing method

Info

Publication number: WO2013164964A1
Application number: PCT/JP2013/061925
Authority: WO
Inventors: 修下宮; 博史安藤
Original assignee: 旭硝子株式会社
Priority date: 2012-05-02
Filing date: 2013-04-23
Publication date: 2013-11-07
Also published as: JP2015131731A; CN104271520A; TW201350447A; CN104271520B; KR20150016223A

Abstract

A sound wave levitation device levitates a glass ribbon that is continuously drawn out from a plate glass forming device by radiation pressure of sound waves when the glass ribbon is conveyed, and is provided with: a diaphragm having an upper surface for radiating sound waves to a portion with a temperature of 300-800°C of the glass ribbon with a width of 1-8 m and a plate thickness of a central portion thereof in a width direction of 0.05-3 mm; and a reflector having an upper surface for reflecting sound waves radiated from the lower surface of the diaphragm. The longitudinal direction of the diaphragm is parallel to the width direction of the glass ribbon, and the cross-sectional shape of the upper surface of the diaphragm is an upward protruding shape.

Description

Sonic levitation device, sonic levitation method, plate glass manufacturing device, and plate glass manufacturing method

The present invention relates to a sonic levitation apparatus, a sonic levitation method, a sheet glass manufacturing apparatus, and a sheet glass manufacturing method.

Conventionally, a plurality of conveyance rolls have been used as an apparatus for horizontally conveying a glass ribbon drawn continuously from a sheet glass forming apparatus (see, for example, Patent Document 1).

On the other hand, in recent years, as a technique for supporting an object in a non-contact manner, a technique has been proposed in which a diaphragm is excited and the object is floated above the diaphragm by radiation pressure of sound waves from the diaphragm (for example, Patent Documents). 2).

Japanese Unexamined Patent Publication No. 2009-155164 Japanese Unexamined Patent Publication No. 7-24415

However, if there is a foreign object or scratch on the outer peripheral surface of the transport roll, there is a problem that the lower surface of the glass ribbon is scratched each time the transport roll makes one revolution.

On the other hand, the technique described in Patent Document 2 is based on the premise that a room temperature object is supported in a non-contact manner, and there is no mention of supporting an object having a temperature higher than room temperature in a non-contact manner.

This invention was made in view of the said subject, Comprising: It aims at provision of the sonic levitation apparatus and the sonic levitation method which can suppress the damage of a glass ribbon.

In order to solve the above problems, one embodiment of the present invention provides:
When conveying a glass ribbon continuously drawn out from a sheet glass forming device, a sonic levitation device that levitates the glass ribbon with a radiant pressure of sound waves,
Among the glass ribbons having a width of 1 to 8 m and a thickness of 0.05 mm to 3 mm in the center in the width direction, a diaphragm having an upper surface that emits sound waves to a portion having a temperature of 300 ° C. to 800 ° C .;
A reflector having an upper surface that reflects sound waves emitted from the lower surface of the diaphragm,
The longitudinal direction of the diaphragm is parallel to the width direction of the glass ribbon,
The cross-sectional shape of the upper surface of the diaphragm is convex upward.

Another embodiment of the present invention is as follows.
When conveying a glass ribbon continuously drawn out from a sheet glass forming apparatus, a sonic levitation method of levitation of the glass ribbon with sonic radiation pressure,
Of the glass ribbon having a width of 1 to 8 m and a thickness of 0.05 mm to 3 mm in the central portion in the width direction, radiation of sound waves radiated from the upper surface of the diaphragm at a temperature of 300 ° C. to 800 ° C. And the sound wave from the lower surface of the diaphragm is reflected on the upper surface of the reflector,
The longitudinal direction of the diaphragm is parallel to the width direction of the glass ribbon,
The cross-sectional shape of the upper surface of the diaphragm is convex upward.

According to the present invention, there is provided a sonic levitation device and a sonic levitation method that can suppress damage to a glass ribbon.

Side surface sectional drawing at the time of the steady state of the plate glass manufacturing apparatus provided with the sonic levitation apparatus by one Embodiment of this invention It is side surface sectional drawing at the time of start-up of the plate glass manufacturing apparatus 100. FIG. FIG. 3 is a sectional view taken along line III-III in FIG. It is a top view which shows the arrangement | sequence of a diaphragm and a support roll. It is an enlarged view which shows the principal part of FIG. It is sectional drawing which shows the modification 1 of FIG. It is sectional drawing which shows the modification 2 of FIG. It is sectional drawing which shows the modification 3 of FIG. It is sectional drawing which shows the modification 4 of FIG. It is sectional drawing which shows the modification 5 of FIG. It is a figure which shows the modification of the shape of a diaphragm.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and description thereof is omitted.

FIG. 1 is a side cross-sectional view of a flat glass manufacturing apparatus provided with a sonic levitation apparatus according to an embodiment of the present invention at a steady state. FIG. 2 is a side cross-sectional view of the plate glass manufacturing apparatus 100 at the time of startup. FIG. 3 is a sectional view taken along line III-III in FIG. FIG. 4 is a top view showing the arrangement of the diaphragm and the support roll. FIG. 5 is an enlarged view showing a main part of FIG. In FIG. 5, the bending of the glass ribbon, the curvature of the diaphragm, and the like are exaggerated from the actual one.

As shown in FIG. 1, the plate glass manufacturing apparatus 100 melts a glass raw material 10 to obtain a molten glass 12, and forms the molten glass 12 obtained by the melting apparatus 200 to obtain a strip-shaped glass ribbon 14. A molding apparatus 300 is provided. Further, the plate glass manufacturing apparatus 100 includes a slow cooling device 400 that gradually cools the glass ribbon 14 formed by the forming device 300, and a lift-out device 500 that transports the glass ribbon 14 from the forming device 300 to the slow cooling device 400. . The lift-out device 500 is provided between the molding device 300 and the slow cooling device 400.

The melting apparatus 200 melts the glass raw material 10 to obtain a molten glass 12. The melting apparatus 200 includes a melting tank 204 that accommodates the molten glass 12 and a burner 206 that forms a flame above the molten glass 12 accommodated in the melting tank 204. The glass raw material 10 thrown into the melting tank 204 is gradually melted into the molten glass 12 by the radiant heat from the flame formed by the burner 206. The molten glass 12 is continuously supplied from the melting tank 204 to the molding apparatus 300.

The forming apparatus 300 is an apparatus that forms the molten glass 12 obtained by the melting apparatus 200 to produce a strip-shaped glass ribbon 14. The molding apparatus 300 may be a float molding apparatus, for example. The float forming apparatus continuously supplies the molten glass 12 to the bath surface of the molten tin 304 in the bathtub 302 and forms it into a strip shape. The formed glass ribbon 14 is pulled up from the bath surface of the molten tin 304 by the lift-out device 500 and conveyed to the slow cooling device 400.

In addition, the shaping | molding apparatus 300 is not limited to a float shaping | molding apparatus, For example, a fusion molding apparatus may be sufficient. The fusion molding apparatus continuously supplies the molten glass 12 to the inside of the ridge, and the molten glass 12 overflowing from the ridge to the left and right sides is merged at the lower edge of the ridge and formed into a strip shape.

The lift-out device 500 includes a heat insulating structure 502 disposed between the molding device 300 and the slow cooling device 400 and a lift-out roll 504 disposed in the internal space of the heat insulating structure 502. The heat insulating structure 502 surrounds the conveyance path of the glass ribbon 14. A heater or a cooler may be provided inside the heat insulating structure 502 in order to adjust the temperature of the glass ribbon 14. The lift-out roll 504 is rotated by a rotary motor (not shown), pulls up the glass ribbon 14 from the bath surface of the molten tin 304 and conveys it to the slow cooling device 400.

The slow cooling device 400 gradually cools the glass ribbon 14 formed by the forming device 300. The slow cooling device 400 includes a slow cooling furnace 402 and a sonic levitation device 410. The sonic levitation device 410 may be provided in any of the slow cooling device 400 and the lift-out device 500, or may be provided across both.

The slow cooling furnace 402 has a plurality of heaters 402a therein. The heater 402a extends in parallel with the width direction of the glass ribbon 14 as shown in FIG. Note that the heater 402 a may be divided into a plurality of pieces in the width direction of the slow cooling furnace 402. The glass ribbon 14 is gradually cooled while being transported horizontally in the slow cooling furnace 402, and is carried out from the outlet of the slow cooling furnace 402. Thereafter, the glass ribbon 14 is cut into a desired size and shape to become a plate glass as a product.

The sonic levitation device 410 levitates the glass ribbon 14 conveyed horizontally in the slow cooling furnace 402 with the radiation pressure of the sonic wave, and supports the glass ribbon 14 in a non-contact manner.

The sonic levitation device 410 includes a vibration plate 411 that emits sound waves that float the glass ribbon 14 and a reflector 450 that reflects sound waves from the lower surface of the vibration plate 411. Among the glass ribbons 14 having a width W0 (see FIGS. 3 and 4) of 1 to 8 m and a thickness of 0.05 mm to 3 mm at the center in the width direction, the temperature is 300 ° C. to 800 ° C. (preferably 500 ° C. The portion of ˜800 ° C., more preferably 600 ° C. to 800 ° C. is levitated by the radiation pressure of the sound wave radiated from the diaphragm 411. Since the above-mentioned portion of the glass ribbon 14 is soft and easily damaged, it is preferable to support the glass ribbon 14 in a non-contact manner by the radiation pressure of sound waves from the diaphragm 411. Note that the diaphragm 411 may be used to float a portion of the glass ribbon 14 having a temperature lower than 300 ° C. with the radiation pressure of sound waves.

The width W0 of the glass ribbon 14 is preferably 2 to 6 m. The plate thickness at the center in the width direction of the glass ribbon 14 is preferably 0.1 mm or more. Moreover, the plate | board thickness of the center part of the width direction of the glass ribbon 14 becomes like this. Preferably it is 1 mm or less, More preferably, it is 0.7 mm or less.

(Diaphragm)
The vibration plate 411 is excited by the vibrator 412, bends and vibrates in the vertical direction, and emits sound waves in the vertical direction. The glass ribbon 14 floats above the diaphragm 411 by the radiation pressure of the sound wave radiated upward from the diaphragm 411.

The sound wave formed by the flexural vibration of the diaphragm 411 is preferably a standing wave. If it is a traveling wave, the glass ribbon 14 may be conveyed in an unintended direction by the radiation pressure of the sound wave from the diaphragm 411. In addition, by optimizing the shape and arrangement of the vibration plate 411, the glass ribbon 14 can be conveyed in a desired direction using the radiation pressure of sound waves from the vibration plate 411.

The frequency of flexural vibration of the diaphragm 411 is preferably 15 kHz to 50 kHz. When the frequency falls below 15 kHz, the frequency becomes human audible range, and the sound becomes an obstacle to work. Generation of vibration exceeding 50 kHz is difficult due to the properties of the power source and the vibrator 412. The frequency is more preferably 18 kHz to 30 kHz, further preferably 19 kHz to 25 kHz, and particularly preferably 19 kHz to 21 kHz.

The amplitude of the flexural vibration of the diaphragm 411 is preferably 0.25 μm to 50 μm. Here, “amplitude” means the maximum displacement from the center of vibration. When the amplitude is 0.25 μm or more, the glass ribbon 14 is sufficiently floated, and when the amplitude is 50 μm or less, damage to the diaphragm 411 and the like can be suppressed.

The longitudinal direction of the vibration plate 411 is parallel to the width direction of the glass ribbon 14. The width direction of the vibration plate 411 is perpendicular to the width direction of the glass ribbon 14 and the vertical direction.

One end in the longitudinal direction of the diaphragm 411 is connected to the vibrator 412 via a vibration transmitting member such as a horn 414 or a booster 416. The vibration of the vibrator 412 is transmitted to one end portion in the longitudinal direction of the diaphragm 411 by a vibration transmitting member. Note that the vibration transmitting member may be omitted, and in this case, the diaphragm 411 and the vibrator 412 are directly connected.

On the other hand, the other end in the longitudinal direction of the diaphragm 411 is a free end. The other end in the longitudinal direction of the diaphragm 411 may be a fixed end, or may be connected to the vibrator 412 via a vibration transmitting member, like the one end in the longitudinal direction of the diaphragm 411. .

For example, as shown in FIG. 5, a plurality of diaphragms 411 are installed at intervals in the conveyance direction of the glass ribbon 14. The pitch P (see FIG. 5) of the diaphragm 411 is preferably 200 mm to 700 mm. If the pitch P is 200 mm or less, a support roll 490 described later cannot be installed on the equipment layout. On the other hand, when the pitch P is 700 mm or more, it is difficult to float without contact. The pitch P of the diaphragm 411 is more preferably 300 mm to 500 mm.

Incidentally, since the plurality of diaphragms 411 are arranged at intervals, the glass ribbon 14 is slightly bent and deformed by gravity. As the glass ribbon 14 is further away from the diaphragm 411, it tends to hang down due to gravity.

Therefore, the cross-sectional shape of the upper surface of the diaphragm 411 is convex upward as shown in FIG. Here, “convex upward” means that a portion between both ends is above a line segment connecting both ends. Thereby, the following effect is acquired. (1) Out of the upper surface of the vibration plate 411, both end portions in the width direction in which almost no sound waves are emitted are positioned below the center portion in the width direction, and the glass ribbon 14 is bent by gravity, and both end portions in the width direction of the vibration plate 411 Can be prevented. (2) Since the sound wave traveling from the upper surface of the vibration plate 411 toward the glass ribbon 14 spreads outward in the width direction of the vibration plate 411, it is possible to prevent contact between the glass ribbon 14 deflected by gravity and both ends of the vibration plate 411 in the width direction. .

The upper surface of the diaphragm 411 has a horizontal linear portion and curved portions extending from both ends of the linear portion in a cross-sectional view as shown in FIG. The curved portion has an upwardly convex shape so as to go downward as it goes outward in the width direction (left-right direction in the figure). The curvature radius r11 of the curved portion is, for example, 150 mm to 1000 mm. The width of the curved portion (the horizontal dimension in the figure) W12 is 5% to 30% of the width W11 of the diaphragm 411.

The cross-sectional shape of the lower surface of the diaphragm 411 may be a horizontal linear shape.

The diaphragm 411 can be easily obtained by grinding the upper surface of a flat plate.

The width of the diaphragm 411 (when the diaphragm 411 is square when viewed from above, the short side length of the diaphragm 411) W11 is preferably 50 mm to 200 mm. When the width W11 is smaller than 50 mm, the area of the sound wave emission surface of the diaphragm 411 is too small, and it is difficult to float the glass ribbon 14 from the diaphragm 411. When the width W11 exceeds 200 mm, the vibration mode of the vibration plate 411 is less likely to be a fringe mode, and the radiation pressure of sound waves is reduced. The width W11 of the diaphragm 411 is more preferably 70 mm to 150 mm, and still more preferably 80 mm to 120 mm.

The width W11 of the diaphragm 411 is preferably 50% to 150% of the width W21 of the reflector 450. When W11 is less than 50% of W21, the reflector 450 and the glass ribbon 14 are likely to contact each other. On the other hand, when W11 exceeds 150% of W21, the diaphragm 411 hardly floats from the reflector 450.

The length L1 (see FIG. 3) of the diaphragm 411 is preferably 95% to 200% of the width W0 of the glass ribbon 14. If L1 is less than 95% of W0, the end of the diaphragm 411 comes into contact with the glass ribbon 14 and scratches are generated. On the other hand, if L1 exceeds 200% of W0, installation on the equipment layout becomes difficult. More preferably, L1 is 100% to 200% of W0.

The length L1 of the diaphragm 411 (see FIG. 3) is preferably 50% to 120% of the length L2 of the reflector 450. When L1 is less than 50% of L2, the diaphragm 411 is convexly bent downward, and the central portion in the longitudinal direction of the diaphragm 411 hangs downward. On the other hand, when L1 exceeds 120% of L2, installation on the facility layout becomes difficult.

The diaphragm 411 is made of, for example, stainless steel, carbon, aluminum, an aluminum alloy, titanium, a titanium alloy, nickel, a nickel alloy, or the like. Stainless steel and carbon are excellent in heat resistance, and aluminum and aluminum alloy are excellent in toughness. When carbon is used, the atmosphere in the slow cooling furnace 402 may be an inert atmosphere such as a nitrogen atmosphere. Moreover, the diaphragm 411 may be formed of ceramics, manganese steel, cast iron, or the like. As a material of the diaphragm 411, stainless steel, aluminum or aluminum alloy is preferable, and stainless steel is more preferable. When the material of the diaphragm 411 is stainless steel, aluminum, or aluminum alloy, the thickness of the diaphragm 411 is, for example, 0.5 mm to 5 mm, preferably 1 mm to 4 mm.

The diaphragm 411 may be surface-coated in order to improve corrosion resistance and oxidation resistance. Examples of the coding method include a thermal spraying method, a plating method, a vapor deposition method (including a PVD method and a CVD method), and the like. The coating layer formed by the thermal spraying method includes, for example, a super hard material such as tungsten carbide, ceramics, or a heat resistant alloy such as a Ni-based alloy or a Cr-based alloy. The coding layer formed by the plating method includes, for example, a Cr-based alloy or a Ni-based alloy. The coding layer formed by the vapor deposition method includes, for example, diamond-like carbon (DLC).

Part of the diaphragm 411 is outside the slow cooling furnace 402. For example, as shown in FIG. 3, the diaphragm 411 passes through the slow cooling furnace 402, and both end portions in the longitudinal direction of the diaphragm 411 are exposed to the outside of the slow cooling furnace 402. Outside the slow cooling furnace 402, the vibrator 412 and the first lifting device 460 that supports the vibrator 412 so as to be movable up and down can be disposed.

(Vibrator)
The vibrator 412 excites the diaphragm 411 and is provided for each diaphragm 411. The plurality of vibrators 412 may vibrate with the same phase or with different phases.

The vibrator 412 may be an ultrasonic vibrator, and is composed of, for example, a piezoelectric element or a magnetostrictive element. The vibrator 412 vibrates longitudinally under the control of a control device such as a computer. When this longitudinal vibration is transmitted to the vibration plate 411, the vibration plate 411 bends and vibrates in the vertical direction, and a sound wave is oscillated from the vibration plate 411 in the vertical direction.

The vibrator 412 is installed outside the slow cooling furnace 402 as shown in FIG. 3 in order to suppress deterioration due to heat. A heat insulating box 430 that houses the vibrator 412 and the like is provided outside the slow cooling furnace 402, and the temperature in the heat insulating box 430 is maintained in a desired temperature range by the cooler 440.

(Insulation box)
A plurality of heat insulation boxes 430 may be provided. In one heat insulation box 430, the vibrator | oscillator 412, the 1st raising / lowering apparatus 460, etc. are arrange | positioned. In the other heat insulating box 430, a second lifting device 470 and the like are arranged.

The heat insulation box 430 includes, for example, a housing 432 and a heat insulating material 434 attached to the inner wall surface of the housing 432. The housing 432 is made of, for example, heat resistant steel such as SS material, and functions as a sound insulating member that blocks noise generated by the vibrator 412 and the like. The heat insulating material 434 is made of, for example, glass wool, gypsum board, or the like, and also functions as a sound absorbing material that absorbs noise generated by the vibrator 412 or the like.

The heat insulating box 430 may be fixed so as to be in contact with the slow cooling furnace 402. However, in order to limit heat transfer from the slow cooling furnace 402, for example, as shown in FIG. Good.

(Cooler)
The cooler 440 is for keeping the temperature in the heat insulation box 430 in a desired temperature range. The cooler 440 is provided for each heat insulation box 430 and is fixed to the heat insulation box 430.

The cooler 440 keeps the inside of the heat insulation box 430 in a desired temperature range, for example, by blowing a cooling gas into the heat insulation box 430 or cooling the outer wall of the heat insulation box 430.

(Reflector)
The reflector 450 has an upper surface that reflects sound waves radiated from the lower surface of the diaphragm 411 toward the diaphragm 411. Due to the radiation pressure of the reflected wave, the diaphragm 411 floats above the reflector 450, and the deformation of the diaphragm 411 by its own weight is reduced. This effect is significant when the other longitudinal end of the diaphragm 411 is a free end.

The reflector 450 has, for example, a substantially quadrangular annular shape, an inverted U shape, an I shape, a T shape, an inverted L shape, or a Z shape (substantially square annular shape in the drawing) to increase the moment of inertia of the cross section. Have The reflector 450 may be plate-shaped. Considering the rigidity of the reflector 450, the cross-sectional shape of the reflector 450 is preferably a substantially quadrangular ring.

A plurality of reflectors 450 are installed at intervals in the conveyance direction of the glass ribbon 14. The reflector 450 is provided for each vibration plate 411, and the longitudinal direction of the reflector 450 is parallel to the width direction of the glass ribbon 14. The width direction of the reflector 450 is perpendicular to the width direction and the vertical direction of the glass ribbon 14.

The upper surface of the reflector 450 reflects sound waves radiated from the lower surface of the diaphragm 411 toward the diaphragm 411. The cross sectional shape of the upper surface of the reflector 450 may be a horizontal straight line. The reflector 450 can be easily manufactured (processed).

The average value of the gap between the reflector 450 and the diaphragm 411 is preferably 30 μm to 120 μm when the diaphragm 411 is vibrating. When the average value of the gap between the reflector 450 and the diaphragm 411 is less than 30 μm, the diaphragm 411 and the reflector 450 are likely to contact each other. On the other hand, that the average value of the gap between the reflector 450 and the diaphragm 411 exceeds 120 μm means that the amplitude of the diaphragm 411 is too large and the diaphragm 411 is easily damaged. The average value of the gap between the reflector 450 and the diaphragm 411 is more preferably 50 μm to 100 μm when the diaphragm 411 is vibrating.

The width W21 of the reflector 450 is preferably 50 mm to 200 mm. If the width W21 of the reflector 450 is smaller than 50 mm, the area of the reflecting surface of the reflector 450 is too small, and it is difficult to lift the diaphragm 411 from the reflector 450. On the other hand, when the width W21 of the reflector 450 exceeds 200 mm, it is difficult to alternately arrange the reflector 450 and a support roll 490 described later. The width W21 of the reflector 450 is more preferably 70 mm to 150 mm, and further preferably 80 mm to 120 mm.

The Young's modulus at room temperature (25 ° C.) of the reflector 450 is preferably 70 GPa or more. By setting it as 70 GPa or more, the weight change of the reflector 450 can fully be suppressed. A more preferable range is 190 GPa or more, and a further preferable range is 210 GPa or more.

The melting point of the reflector 450 is preferably 1300 ° C. or higher. By setting it as 1300 degreeC or more, softening of the reflector 450 can fully be suppressed. A more preferable range is 1500 ° C. or higher, and a further preferable range is 1700 ° C. or higher.

The reflector 450 is made of, for example, heat resistant steel such as stainless steel or ceramic such as silica. Examples of stainless steel include SUS310S.

A part of the reflector 450 comes out of the slow cooling furnace 402. For example, as shown in FIG. 3, the reflector 450 passes through the slow cooling furnace 402, and both longitudinal ends of the reflector 450 are exposed to the outside of the slow cooling furnace 402. Therefore, the 1st and 2nd raising / lowering

apparatuses

460 and 470 which support the reflector 450 so that raising / lowering is possible can be installed in the slow cooling furnace 402 outside.

(First lifting device)
The first elevating device 460 is configured by, for example, a hydraulic jack or the like, and supports one end portion of the diaphragm 411 through the vibrator 412 so as to be movable up and down. As the vibration plate 411 moves up and down with respect to the hearth of the slow cooling furnace 402, the positional relationship with the glass ribbon 14 can be optimized. The first lifting device 460 is provided for each diaphragm 411.

Also, the first lifting device 460 supports one end of the reflector 450 so as to be lifted and lowered. The diaphragm 411 and the reflector 450 can be moved up and down independently so that the positional relationship can be adjusted.

(Second lifting device)
The second lifting / lowering device 470 is composed of, for example, a hydraulic jack or the like, and supports the other end of the reflector 450 so as to be liftable. The second lifting device 470 moves the reflector 450 up and down relative to the hearth of the slow cooling furnace 402 in synchronization with the first lifting device 460. The second lifting device 470 is provided for each reflector 450.

One or more lifting devices that support the reflector 450 so as to be movable up and down may be provided between the first lifting device 460 and the second lifting device 470. The bending of the reflector 450 is reduced, and the floating of the diaphragm 411 can be stabilized.

(Transport roll)
A plurality of transport rolls 480 are provided at intervals in the transport direction of the glass ribbon 14. The transport roll 480 is driven by a rotary motor and transports the glass ribbon 14 horizontally.

The transport roll 480 is disposed in a low temperature region of the glass ribbon 14 so as not to damage the glass ribbon 14. For example, the transport roll 480 is preferably provided downstream of the slow cooling furnace 402 as shown in FIG.

Note that the transport roll 480 may be provided inside the slow cooling furnace 402. In this case, the transport roll 480 and the diaphragm 411 may be alternately arranged so that the contact pressure between the transport roll 480 and the glass ribbon 14 is lowered.

(Support roll)
The support roll 490 is provided inside the slow cooling furnace 402 and can support the glass ribbon 14 from below. A plurality of support rolls 490 are provided at intervals in the conveyance direction of the glass ribbon 14.

Between the adjacent support rolls 490, one diaphragm 411 is disposed, and the support roll 490 and the diaphragm 411 are alternately and repeatedly arranged. The arrangement order of the support roll 490 and the diaphragm 411 may be various.

The support roll 490 and the diaphragm 411 can be moved up and down relatively. For example, the support roll 490 can be moved up and down with respect to the hearth of the slow cooling furnace 402, as will be described in detail later, depending on the situation, a position for supporting the glass ribbon 14 from below (see FIG. 2), and a glass ribbon 14 and moved to a retracted position (see FIG. 1) that is separated from 14.

In addition, in this embodiment, although the support roll 490 raises / lowers, the diaphragm 411 may raise / lower. As the vibration plate 411 moves up and down, the support roll 490 can support the glass ribbon 14 from below or be separated from the glass ribbon 14.

(How to use support roll)
For example, when the plate glass manufacturing apparatus 100 is started up, the thickness and shape of the glass ribbon 14 become uneven. Therefore, it may be difficult to float the glass ribbon 14 above the diaphragm 411 only with the radiation pressure of the sound wave from the diaphragm 411.

Therefore, when the plate glass manufacturing apparatus 100 is started up, as shown in FIG. 2, the support roll 490 supports the glass ribbon 14 from below and prevents the glass ribbon 14 and the diaphragm 411 from contacting each other. The support roll 490 is rotated by a rotary motor and conveys the glass ribbon 14 in a predetermined direction.

On the other hand, when the plate glass manufacturing apparatus 100 is in a steady state (at the time of plate glass manufacture), as shown in FIG. 1, the support roll 490 is separated from the glass ribbon 14, and the radiating pressure of sound waves from the vibration plate 411 The glass ribbon 14 is levitated above. Since the support roll 490 and the glass ribbon 14 do not contact, damage to the glass ribbon 14 can be prevented. After the support roll 490 is separated from the glass ribbon 14, the rotation motor that rotates the support roll 490 is stopped.

Note that the support roll 490 can be omitted by arranging the plurality of diaphragms 411 closely.

Although one embodiment of the present invention and modifications thereof have been described above, the present invention is not limited to the above-described embodiment and the like, and various modifications are possible within the scope of the gist of the present invention described in the claims. Can be modified and changed.

For example, as shown in FIG. 6, the diaphragm 411 may have a plurality of through holes 411a. A rectangular tube-shaped reflector 450 is disposed below the diaphragm 411, and a plurality of ejection holes 450 a for ejecting the gas supplied to the inner space of the reflector 450 to the outside are formed on the reflector 450. Yes. The gas ejected from the ejection hole 450a passes through the through-hole 411a of the vibration plate 411 and is blown to the lower surface of the glass ribbon 14 to float the glass ribbon 14. Moreover, since gas is supplied into the slow cooling furnace 402, the temperature in the slow cooling furnace 402 can be adjusted. The gas ejected from the ejection hole 450a may be SO ₂ gas. The SO ₂ gas can form a scratch-proof film on the lower surface of the glass ribbon 14.

Further, the sonic levitation device 410A of FIG. 7 includes a diaphragm 411A and a reflector 450. The upper surface of the diaphragm 411A has a horizontal linear portion and an inclined portion extending obliquely downward from both ends of the linear portion in a cross-sectional view. The inclined portion is formed so as to go downward as it goes outward in the width direction (left-right direction in the figure). An angle θ formed by the inclined portion and the horizontal direction is, for example, 15 ° to 60 °. The width of the inclined portion (the horizontal dimension in the drawing) W12 is, for example, 5% to 30% of the width W11 of the diaphragm 411A. Thus, the cross-sectional shape of the upper surface of the vibration plate 411A is convex upward. Therefore, also in this modification, the effects (1) and (2) can be obtained as in the above embodiment. The cross-sectional shape of the lower surface of the diaphragm 411A is a horizontal straight line.

Further, the sonic levitation device 410B of FIG. 8 includes a diaphragm 411B and a reflector 450. The cross-sectional shape of the upper surface of the diaphragm 411B is an upwardly convex curve. Therefore, also in this modification, the effects (1) and (2) can be obtained as in the above embodiment. In addition, in the present modification, (3) a uniform gap is formed between the glass ribbon 14 deflected by gravity and the vibration plate 411B, and sound waves radiated from most of the upper surface of the vibration plate 411B are emitted from the glass ribbon 14. This contributes to the ascent of the buoyant and provides sufficient levitation force. If the gap is too wide, sufficient levitation force cannot be obtained, and if the gap is too narrow, the glass ribbon 14 and the diaphragm 411B come into contact with each other.

The curvature radii R11 of the upper surface of the diaphragm 411B are 150 mm to 10000 mm, respectively. If the curvature radius R11 of the upper surface of the vibration plate 411B is less than 150 mm, the gap formed between the glass ribbon 14 bent by gravity and the vibration plate 411B becomes non-uniform, and radiation is performed from most of the upper surface of the vibration plate 411B. The glass ribbon 14 is less likely to be lifted by the generated sound wave, and the lift force is weakened. On the other hand, when the curvature radius R11 of the upper surface of the diaphragm 411B exceeds 10,000 mm, the glass ribbon 14 bent by gravity and the both ends in the width direction of the diaphragm 411B are likely to come into contact with each other. The curvature radius R11 of the upper surface of the diaphragm 411B is preferably 300 mm to 8000 mm, more preferably 500 mm to 7000 mm. Note that the cross-sectional shape of the lower surface of the diaphragm 411B is a horizontal straight line.

Further, the sonic levitation device 410C of FIG. 9 includes a diaphragm 411C and a reflector 450C. The cross-sectional shape of the upper surface of the vibration plate 411C is an upward convex curve. Therefore, also in this modified example, the effects (1) to (3) can be obtained as in the modified example of FIG. In addition, in this modification, the cross-sectional shape of the lower surface of the vibration plate 411C is a curved shape that is convex upward (concave downward). The curvature radius R12 of the lower surface of the diaphragm 411C may be smaller than the curvature radius R11 of the upper surface of the diaphragm 411C by the thickness of the diaphragm 411C. The diaphragm 411C can be easily obtained by bending a flat plate. The vibration plate 411C may be manufactured by grinding a flat plate.

When the cross-sectional shape of the lower surface of the diaphragm 411C is an upwardly convex curved shape, if the cross-sectional shape of the upper surface of the reflector 450C is an upwardly convex curved shape, the diaphragm 411C and the reflector 450C A uniform gap is formed, and sound waves reflected from most of the upper surface of the reflector 450C contribute to the floating of the vibration plate 411C, and a sufficient floating force is obtained.

The curvature radius R21 of the upper surface of the reflector 450C is 90% to 110% (preferably, the curvature radius R12 of the lower surface of the diaphragm 411C so that a uniform gap is formed between the reflector 450C and the diaphragm 411C. 90% to 100%). More preferably, the radius of curvature R21 of the upper surface of the reflector 450C is smaller than the radius of curvature R12 of the lower surface of the diaphragm 411C by the gap between the reflector 450C and the diaphragm 411C.

10 includes the vibration plate 411C in FIG. 9 and the reflector 450 in FIG. Therefore, also in this modified example, the effects (1) to (3) can be obtained as in the modified example of FIG. In addition, in this modified example, the vibration plate 411C can be easily manufactured (processed) as in the example of FIG. 9, and the processing cost and processing accuracy of the vibration plate 411C are good. Further, in this modification, the reflector 450 can be easily manufactured (processed) as in the examples of FIGS. 5 to 8, and the processing cost and processing accuracy of the reflector 450 are good. Here, when the curvature radius R11 of the upper surface of the vibration plate 411C and the curvature radius R12 of the lower surface of the vibration plate 411C are 500 mm or more, the gap between the vibration plate 411C and the reflector 450 approaches uniformly, and the reflector 450 The sound wave reflected from most of the upper surface of the plate contributes to the levitation of the diaphragm 411C, and an effective levitation force is obtained.

FIG. 11 is a diagram showing a modification of the shape of the diaphragm. In FIG. 11, the bending of the diaphragm and the bending of the glass ribbon are illustrated exaggerated than actual.

Rolls such as the lift-out roll 504 and the transport roll 480 shown in FIG. 1 and the like are supported at both axial ends, and are not supported at the central portion in the axial direction. Therefore, the axial center part of a roll may fall rather than the axial direction both ends of a roll by dead weight. As a result, the width direction center part of the glass ribbon 14 may fall rather than the width direction both ends of the glass ribbon 14. FIG. Moreover, the center part of the width direction of the glass ribbon 14 may fall rather than the both ends of the width direction of the glass ribbon 14 irrespective of the bending of a roll.

Therefore, when the vibration is stopped, the upper end of the first portion 411D-1 corresponding to the glass ribbon width direction center portion of the vibration plate 411D has the second portion 411D-2 corresponding to both ends of the vibration plate 411D in the glass ribbon width direction, and It may be below the upper end of each of the third portions 411D-3. Here, the part corresponding to both ends of the glass ribbon width direction means a part located immediately below both ends of the glass ribbon width direction. If the length of the vibration plate 411D is 95% or more of the width of the glass ribbon 14, the second portion 411D-2 and the third portion 411D-3 corresponding to both ends of the vibration plate 411D in the glass ribbon width direction exist. When the diaphragm length is slightly shorter than the glass ribbon width (95% or more and less than 100%), both end portions in the length direction of the diaphragm correspond to the above-described 411D-2 and 411D-3.

As described above, if the upper end of the first portion 411D-1 is below the respective upper ends of the second portion 411D-2 and the third portion 411D-3, the glass ribbon 14 is bent convexly downward. The glass ribbon 14 is less likely to come into contact with the diaphragm 411D, and the glass ribbon 14 is less likely to be damaged.

In the present embodiment, the upper end of the first portion 411D-1 is lower than the upper ends of the second portion 411D-2 and the third portion 411D-3, but they may be at the same height. The height means a position in the vertical direction. If the upper end of the first portion 411D-1 is not higher than the upper ends of the second portion 411D-2 and the third portion 411D-3, contact between the glass ribbon 14 and the diaphragm 411D can be limited to some extent.

The height difference H2 between the upper end of the first portion 411D-1 and the upper end of the second portion 411D-2, and the height difference H3 between the upper end of the first portion 411D-1 and the upper end of the third portion 411D-3, respectively. It is 0% to 0.1% (preferably 0.01% to 0.1%, more preferably 0.02% to 0.1%) of the width W0 of the glass ribbon 14.

In the present embodiment, the lower end of the first portion 411D-1 is above the lower ends of the second portion 411D-2 and the third portion 411D-3, but they may be at the same height. May be below.

This application claims priority based on Japanese Patent Application No. 2012-105514 filed with the Japan Patent Office on May 2, 2012. The entire contents of Japanese Patent Application No. 2012-105514 are incorporated herein by reference. Incorporate.

DESCRIPTION OF SYMBOLS 10 Glass raw material 12 Molten glass 14 Glass ribbon 100 Sheet glass manufacturing apparatus 200 Melting apparatus 300 Molding apparatus 400 Slow cooling apparatus 402 Slow cooling furnace 410 Sonic levitation apparatus 411 Vibration plate 412 Vibrator 430 Heat insulation box 440 Cooler 450 Reflector 460 First lifting apparatus 470 Second lifting device 480 Conveying roll (conveying means)
490 Support roll 500 Lift-out device

Claims

When conveying a glass ribbon continuously drawn out from a sheet glass forming device, a sonic levitation device that levitates the glass ribbon with a radiant pressure of sound waves,
Among the glass ribbons having a width of 1 to 8 m and a thickness of 0.05 mm to 3 mm in the center in the width direction, a diaphragm having an upper surface that emits sound waves to a portion having a temperature of 300 ° C. to 800 ° C .;
A reflector having an upper surface that reflects sound waves emitted from the lower surface of the diaphragm,
The longitudinal direction of the diaphragm is parallel to the width direction of the glass ribbon,
The sonic levitation device, wherein the cross-sectional shape of the upper surface of the diaphragm is convex upward.
In the vibration stopped state, the upper ends of the first portions corresponding to the glass ribbon width direction central portion of the diaphragm are the upper ends of the second portion and the third portion corresponding to the glass ribbon width direction both ends of the vibration plate, respectively. Below or at the same height,
The height difference between the upper end of the first portion and the upper end of the second portion, and the height difference between the upper end of the first portion and the upper end of the third portion are 0% to 0% of the width of the glass ribbon, respectively. The sonic levitation device of claim 1, which is 1%.
The acoustic levitation device according to claim 1 or 2, wherein the reflector has a Young's modulus at room temperature of 70 GPa or more.
The sonic levitation apparatus according to any one of claims 1 to 3, wherein the reflector has a melting point of 1300 ° C or higher.
The sonic levitation apparatus according to any one of claims 1 to 4, wherein the diaphragm is made of stainless steel.
The sonic levitation apparatus according to any one of claims 1 to 4, wherein the diaphragm is formed of aluminum or an aluminum alloy.
6. The sonic levitating apparatus according to claim 1, wherein the vibration plate has a frequency of 15 kHz to 50 kHz when the portion of the glass ribbon is levitated by a radiation pressure of sound waves.
The acoustic wave according to any one of claims 1 to 7, wherein the vibration plate has an amplitude of 0.25 to 50 µm when a portion of the glass ribbon having a temperature of 300 ° C to 800 ° C is levitated by the radiation pressure of the acoustic wave. Levitation device.
The sonic levitation apparatus according to any one of claims 1 to 8, further comprising conveying means for conveying the glass ribbon in a predetermined direction.
Further comprising a support roll capable of supporting the glass ribbon from below;
The sonic levitation apparatus according to claim 9, wherein the support roll is movable up and down relatively with respect to the diaphragm.
A plate glass manufacturing apparatus having the sonic levitation apparatus according to any one of claims 1 to 10.
When conveying a glass ribbon continuously drawn out from a sheet glass forming apparatus, a sonic levitation method of levitation of the glass ribbon with sonic radiation pressure,
Of the glass ribbon having a width of 1 to 8 m and a thickness of 0.05 mm to 3 mm in the central portion in the width direction, radiation of sound waves radiated from the upper surface of the diaphragm at a temperature of 300 ° C. to 800 ° C. And the sound wave from the lower surface of the diaphragm is reflected on the upper surface of the reflector,
The longitudinal direction of the diaphragm is parallel to the width direction of the glass ribbon,
The sonic levitation method, wherein the cross-sectional shape of the upper surface of the diaphragm is convex upward.
In the vibration stopped state, the upper ends of the first portions corresponding to the glass ribbon width direction central portion of the diaphragm are the upper ends of the second portion and the third portion corresponding to the glass ribbon width direction both ends of the vibration plate, respectively. Below or at the same height,
The height difference between the upper end of the first portion and the upper end of the second portion, and the height difference between the upper end of the first portion and the upper end of the third portion are 0% to 0% of the width of the glass ribbon, respectively. The sonic levitation method according to claim 11, which is 1%.
A plate glass manufacturing method comprising a step of levitation of the glass ribbon with a sonic radiation pressure by the sonic levitation method according to claim 12 or 13 when transporting a glass ribbon continuously drawn from a plate glass forming apparatus.