JP2016030714A - Apparatus and method for molding sheet glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase productivity of a sheet glass.SOLUTION: An apparatus for molding a sheet glass according to the present invention comprises a conveyance mechanism, a first detection part, a first speed control part, a second detection part, and a second speed control part. The conveyance mechanism conveys a molten glass which flows out of a melting furnace. The first detection part detects the condition of flowing-out molten glass staying on the conveyance mechanism. The first speed control part controls a conveyance speed of the molten glass conveyed by the conveyance mechanism based upon a detection result of the first detection part. The second detection part detects information corresponding to time change in conveyance speed controlled by the first speed control part. The second speed control part corrects the conveyance speed controlled by the first speed control part based upon a detection result of the second detection part.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a sheet glass forming apparatus and a method for forming sheet glass for forming molten glass into a plate shape.

  The plate-like glass forming apparatus adjusts the thickness and width of the molten glass through a rolling roller and a conveyance guide for width regulation, for example, while conveying the molten glass continuously flowing out from the melting furnace onto the conveyor. A plate-shaped glass having a desired shape is obtained (see Patent Document 1).

  The plate-like glass forming apparatus described above has a function of measuring the shape of the molten glass pool on the conveyor and controlling the conveying speed of the conveyor based on the measurement result for the following reason. That is, if the conveyor transport speed is slow and the molten glass pool becomes large, striae or distortion occurs in the plate-shaped glass after work forming, leading to a decrease in yield. On the other hand, if the conveyor transport speed is high and the pool of molten glass is small, the plate-shaped glass after work forming becomes insufficient in thickness, making it difficult to obtain the desired thickness and width.

  However, in general, such speed control for molten glass with low fluidity has a large time lag from the start of changing the conveying speed until the shape of the molten glass pool actually changes. It is easy to occur and has a problem about responsiveness.

  In addition, the operator artificially controls the conveying speed of the conveyor by turning, for example, a dedicated adjusting knob for adjusting the speed while visually checking the shape of the molten glass pool through a monitor camera or the like. It is also possible to configure a plate-like glass forming apparatus. However, in this case, it is necessary to always ensure the number of man-hours by the worker, and there remains a problem in terms of manufacturing cost.

JP 2003-192361 A

  This invention is made | formed in order to solve the said subject, and it aims at provision of the shaping | molding method of a plate glass forming apparatus and plate glass which can improve productivity of plate glass.

  The sheet glass forming apparatus of the present invention includes a transport mechanism, a first detection unit, a first speed control unit, a second detection unit, and a second speed control unit. A conveyance mechanism conveys the molten glass which flows out from a melting furnace. A 1st detection part detects the condition where the said molten glass which flows out accumulates on a conveyance mechanism. A 1st speed control part controls the conveyance speed of the molten glass by a conveyance mechanism based on the detection result by a 1st detection part. The second detection unit detects information corresponding to a temporal change in the transport speed controlled by the first speed control unit. The second speed control unit corrects the transport speed controlled by the first speed control unit based on the detection result by the second detection unit.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the sheet glass shaping | molding apparatus which can improve the productivity of sheet glass, and the shaping | molding method of sheet glass.

The perspective view which shows roughly the plate-shaped glass forming apparatus which concerns on embodiment of this invention. The block diagram which shows notionally the speed control system about the conveyance mechanism with which the plate-shaped glass forming apparatus of FIG. 1 was equipped. The block diagram which shows the speed control system about the conveyance mechanism with which the plate-shaped glass forming apparatus of FIG. 1 was equipped functionally. The top view for demonstrating the judgment of the condition of the accumulation of the molten glass by the plate-shaped glass forming apparatus of FIG. The figure which shows the fluctuation | variation of the drive frequency of an inverter motor at the time of applying the plate-shaped glass forming apparatus of the comparative example 1. FIG. The figure which shows the fluctuation | variation of the drive frequency of an inverter motor at the time of applying the plate-shaped glass forming apparatus of the comparative example 2. FIG. The figure which shows the fluctuation | variation of the drive frequency of an inverter motor at the time of applying the plate-shaped glass forming apparatus of FIG. The flowchart which shows the shaping | molding method by the plate-shaped glass shaping | molding apparatus of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the sheet glass forming apparatus 10 of this embodiment mainly includes a transport mechanism 7, a rolling roller 14, a pair of guide members 9a and 9b, a cutting unit 15, and the like. The conveyance mechanism 7 conveys the molten glass 5a that continuously flows out from the outlet 8a of the melting furnace (crucible kiln) 8 in a molten state. The melting furnace 8 is a pot furnace in which a new glass material needs to be charged again every time the glass material in the melting furnace runs out.

  As shown in FIG. 1, the transport mechanism 7 includes a plate conveyor 7a, an inverter motor 7b, a plurality of conveyor transfer rollers 7c, and the like. The plate conveyor 7a is an endless (endless) chain conveyor (endless track) in which a plurality of strip-shaped plates 7d are connected. Each plate 7d is formed of a material having excellent heat resistance and corrosion resistance. In the plate conveyor 7a, the individual plates 7d are connected so that the molten glass 5a does not flow into the gap between adjacent plates 7d so that the gap is 1 mm or less.

  The inverter motor 7b is a drive source of the transport mechanism 7, and rotates at a rotation speed corresponding to the drive frequency of the motor drive signal output from the inverter circuit. The plurality of conveyor transfer rollers 7c guide the movement of the plate conveyor 7a while rotating by the driving force from the inverter motor 7b being applied via a speed reduction mechanism or the like.

  The rolling roller 14 rolls the molten glass 5a conveyed by the conveyance mechanism 7 and forms it in the thickness direction. The rolling roller 14 is formed of a metal material having excellent heat resistance and corrosion resistance. A plurality of rolling rollers 14 may be provided. It is also possible to arrange a single or a plurality of auxiliary rollers on the downstream side of the rolling roller 14 in the conveying direction by the conveying mechanism 7. The auxiliary roller is arranged for the purpose of adjusting the thickness of the molten glass 5a rolled by the rolling roller 14. The rolling roller 14 and the auxiliary roller are supplied with a coolant such as cooling water, for example, and cool the molten glass 5a in contact with the surfaces of these rollers.

  As shown in FIG. 1, the pair of guide members 9a and 9b regulate the conveyance width of the molten glass 5a. That is, the pair of guide members 9a and 9b regulates the movement of the molten glass 5a conveyed by the conveyance mechanism 7 in the width direction via the guide surfaces 9c and 9d provided in FIG. The guide members 9a and 9b are arranged in a state where pipes and the like are in contact with each other. This pipe is configured such that a coolant such as cooling water for cooling the guide members 9a and 9b heated by the molten glass flows.

  The guide surfaces 9c and 9d of the guide members 9a and 9b and the contact surface of the plate 7d with the molten glass 5a are finished smoothly. As a material of the plate 7d, for example, a metal such as stainless steel such as SUS304, SUS304L, SUS321, SUS316, SUS316L, and SUS310S, a stone material, ceramics, and the like are exemplified. The cutting unit 15 cuts a plate-like glass (molded glass) 5c processed and formed by the rolling roller 14 and the pair of guide members 9a and 9b into a predetermined length.

  Next, the speed control system of the transport mechanism 7 provided in the sheet glass forming apparatus 10 will be described in detail based on FIGS. 2 to 4 in addition to FIG. As shown in FIG. 2, the speed control system of the transport mechanism 7 conceptually includes a first feedback processing unit 11 and a second feedback control unit for performing two-stage feedback control on the drive frequency of the inverter motor 7b. A feedback processing unit 12 is provided.

  That is, as shown in FIG. 3, the first feedback processing unit 11 includes a first detection unit 17 and a first speed control unit 21. The 1st detection part 17 detects the condition where the molten glass 5a which flows out continuously from the melting furnace 8 accumulates on the conveyance mechanism 7 in conveyance. The first speed control unit 21 controls the conveyance speed of the molten glass 5 a by the conveyance mechanism 7 based on the detection result by the first detection unit 17.

  On the other hand, the second feedback processing unit 12 includes a second detection unit 25 and a second speed control unit 32. Furthermore, the speed control selection unit 31 and the drive frequency detection unit 34 are provided in the speed control system of the transport mechanism 7. The 2nd detection part 25 detects the information corresponding to the time change of the conveyance speed (conveyance speed of the molten glass 5a by the conveyance mechanism 7) controlled by the 1st speed control part 21. FIG.

  The second detection unit 25 has a rate of change corresponding to the passage of time of the drive frequency of the inverter motor 7b (drive frequency of the inverter motor 7b output from the inverter circuit) as information corresponding to the time change of the transport speed. And an average value of the drive frequency for each predetermined elapsed time. The second speed control unit 32 corrects the transport speed controlled by the first speed control unit 21 based on the detection result by the second detection unit 25.

  Specifically, the first detection unit 17 described above includes a camera 18, an image processing unit 19, and a pool region determination unit 20. As shown in FIGS. 1, 3 and 4, the camera 18 has a molten glass pool (glass pool) 5b on the transport mechanism 7 (plate conveyor 7a) on at least one side of the pair of guide members 9a and 9b. To capture the video. The image processor 19 binarizes the video captured by the camera 18 so that the plate surface of the plate conveyor 7a and the molten glass pool 5b can be distinguished.

  As shown in FIG. 4, the accumulation region determination unit 20 sets a accumulation target region 1, a deceleration region 3, and an acceleration region 2 in the video image processed by the image processing unit 19. The accumulation target region 1, the deceleration region 3, and the acceleration region 3 are positions of the guide surface (the guide surface 9c of the guide member 9a in this embodiment) of at least one of the pair of guide members 9a and 9b. Set to include.

  More specifically, as shown in FIG. 4, the accumulation region determination unit 20 of the first detection unit 17 has a position where the molten glass 5 a flows out of the melting furnace 8 and the installation of the rolling roller 14 in the conveyance direction by the conveyance mechanism 7. A reference pool target area 1 is set between the positions. Further, the accumulation area determination unit 20 sets a deceleration area 2 on the downstream side of the accumulation target area 1 and sets an acceleration area 3 on the upstream side of the accumulation target area 1 in the conveyance direction by the conveyance mechanism 7.

  Furthermore, the accumulation area determination unit 20 indicates that the molten glass accumulation 5b remains in the deceleration area 2 set downstream of the accumulation target area 1 or the molten glass accumulation 5b exceeds the accumulation target area 1. Is also detected to reach the acceleration region 3 set on the upstream side. When it is detected that the molten glass pool 5b remains in the deceleration area 2, the first speed control unit 21 decelerates the conveyance speed by the conveyance mechanism 7, and the molten glass pool 5b When it is detected that the position has reached, the transport speed by the transport mechanism 7 is accelerated. That is, the first speed control unit 21 decelerates the conveyance speed when the molten glass pool 5b is smaller than the specified value, and accelerates the conveyance speed when the molten glass pool 5b is larger than the defined value. .

  More specifically, as shown in FIG. 4, the accumulation area determination unit 20 includes a plurality of subdivided deceleration areas (which will be described later) by further subdividing the deceleration area 2 and the acceleration area 3 in the conveyance direction by the conveyance mechanism 7. An adjustment deceleration area 2a, a basic adjustment deceleration area 2b, an excessive accumulation avoidance deceleration area 2c) and a plurality of subdivision acceleration areas (a fine adjustment acceleration area 3a, a basic adjustment acceleration area 3b, and an excessive accumulation avoidance acceleration area 3c described later) are set. To do. Furthermore, the pool area determination unit 20 indicates that the molten glass pool 5b remains in any of the plurality of subdivision deceleration areas, or the molten glass pool 5b exists in any of the plurality of subdivision acceleration areas. Detect that it has arrived. The accumulation area determination unit 20 updates the determination result every 10 seconds (10 seconds), for example.

  Further, when it is detected that the molten glass pool 5b remains in one of the plurality of subdivision acceleration regions, the first speed control unit 21 remains in the further subdivision deceleration region. When the rate at which the conveyance speed is reduced is increased, and it is detected that the molten glass pool 5b has reached one of the plurality of subdivision acceleration regions, it reaches the further subdivision acceleration region. Increasing the rate at which the transport speed is accelerated is increased.

  That is, as shown in FIG. 3, the first speed control unit 21 includes a frequency increase / decrease unit 22, a first reference frequency storage update unit 23, and an adder 24. Here, the drive frequency detector 34 described above detects and outputs a drive frequency of a motor drive signal for driving the inverter motor 7b. The first reference frequency storage update unit 23 stores (overwrites) the drive frequency of the inverter motor 7b detected by the drive frequency detection unit 34 while updating the drive frequency as the first reference frequency, for example, every 10 seconds. In addition, before the start of the inverter motor 7b, the first reference frequency storage update unit 23 stores a predetermined drive frequency such as 60 Hz in advance.

  As shown in FIGS. 3 and 4, the frequency increasing / decreasing unit 22 is such that the molten glass pool 5b remains in the fine adjustment deceleration area 2a, the basic adjustment deceleration area 2b, or the accumulation under-avoidance deceleration area 2c. When detected by the accumulation area determination unit 20, the frequency of a predetermined interval, for example, −0.5 Hz, −3.5 Hz, and −4.5 Hz, respectively, is output. Further, the frequency increase / decrease unit 22 detects that the molten glass pool 5b has reached the fine adjustment acceleration region 3a, the basic adjustment acceleration region 3b, or the excessive accumulation avoidance acceleration region 3c. For example, +0.4 Hz, +2.5 Hz, and +4.5 Hz are output, respectively.

  The frequency increase / decrease unit 22 updates the frequency value to be output every 10 seconds, for example, so as to be linked with the determination result by the accumulation region determination unit 20. The adder 24 adds the first reference frequency updated by the first reference frequency storage update unit 23 and the frequency from the frequency increase / decrease unit 22 and outputs the result to the speed control selection unit 31.

  On the other hand, as described above, the second detection unit 25 uses the change rate according to the passage of time of the drive frequency of the inverter motor 7b and the change rate of the inverter motor 7b as information corresponding to the time change of the transport speed by the transport mechanism 7. An average value of the driving frequency at every constant elapsed time is detected. That is, the second detection unit 25 includes a second reference frequency calculation unit 26 and a time change rate calculation unit 30, as shown in FIG. The second reference frequency calculation unit 26 includes an integration unit 27, an average value calculation unit 28, and a reference frequency setting unit 29.

  The integrating unit 27 integrates the driving frequency of the motor driving signal for driving the inverter motor 7b detected by the driving frequency detecting unit 34, for example, every 1 sec. The average value calculation unit 28 averages the accumulated frequencies, for example, every 1 min (minutes). The reference frequency setting unit 29 sets the averaged frequency as a second reference frequency (intercept), and outputs the second reference frequency to the speed control selection unit 31.

  The time change rate calculation unit 30 calculates a deviation between the second reference frequency set by the reference frequency setting unit 29 and the drive frequency of the inverter motor 7b detected by the drive frequency detection unit 34, for example, every 1 sec. Then, the amount of change in frequency per unit time (sec slope) is output to the adder 33 of the second speed control unit 32 every 1 sec. The second speed control unit 32 includes the adder 33 described above. The adder 33 adds the output of the speed control selection unit 31 and the above-described deviation.

Here, when the amount of change (slope) of the frequency is Δf _FB2 [Hz], the second reference frequency (intercept) is f _nor [Hz], and the time [sec] is t, the second feedback processing unit 12 obtains it. The frequency f (t) to be obtained is defined by the following Equation 1 as a linear function.

f (t) = Δf _FB2 · t + f _nor .

  Here, as shown in FIG. 3 and FIG. 4, the first detection unit 17 having the pool region determination unit 20 can also detect that the molten glass pool 5 b has accumulated in the target region 1. is there. Further, when the first detection unit 17 detects that the molten glass pool 5b remains in the pool target area 1, the speed control selection unit 31 invalidates the speed control by the first speed control unit 21. And the time rate of change (time rate of change of the drive frequency of the inverter motor 7b) by the second speed control unit 32 and the average value (second reference frequency) of the drive frequency of the inverter motor 7b per unit time The control of the conveyance speed in the conveyance mechanism 7 based on the above is selected.

  Specifically, the speed control selection unit 31 adds the first speed control unit 21 when the pool region determination unit 20 determines that the molten glass pool 5b does not remain in the pool target region 1. The output of the vessel 24 is selected, and when the pool region determination unit 20 determines that the molten glass pool 5b remains in the pool target region 1, the reference frequency setting unit of the second reference frequency calculation unit 26 The switch is switched to select 29 outputs.

  That is, since the speed control selection unit 31 performs the switching control to achieve precise speed control at the transport speed of the transport mechanism 7, the state of the molten glass pool 5b is continuously maintained in an appropriate state. It becomes possible.

  Here, control of the conveyance speed with respect to the molten glass by the comparative examples 1 and 2 and control of the conveyance speed of the molten glass by the sheet glass forming apparatus 10 of this embodiment are compared based on FIGS. FIG. 5 applies the plate-like glass forming apparatus of Comparative Example 1 that does not have the speed control system shown in FIG. 3, and the operator visually observes the shape of the molten glass pool through a monitor camera. This shows the fluctuation of the drive frequency of the inverter motor when the speed control is artificially performed by turning a dedicated adjustment knob for speed adjustment.

  6 drives the output of the adder 24 of the first speed control unit 21 without providing the second feedback processing unit 12 and the speed control selection unit 31 in the speed control system shown in FIG. The fluctuation | variation of the drive frequency of an inverter motor at the time of applying the plate-shaped glass forming apparatus of the comparative example 2 made to output directly to the frequency detection part 34 is shown. Moreover, FIG. 7 shows the fluctuation | variation of the drive frequency of the inverter motor 7b at the time of applying the sheet glass forming apparatus 10 of this embodiment provided with the speed control system shown in FIG.

  As shown in FIG. 6, the plate-like glass forming apparatus of Comparative Example 2 that does not have the second feedback processing unit 12 has a large fluctuation in the drive frequency of the inverter motor, and there is a concern about the occurrence of a hunting phenomenon or the like. On the other hand, as shown in FIG. 7, the sheet glass forming apparatus 10 of the present embodiment having the first and second feedback processing units 11 and 12 is artificially controlled with the comparative example 1 shown in FIG. Similarly, it is possible to reduce fluctuations in the drive frequency of the inverter motor 7b. Thereby, since the plate-shaped glass forming apparatus 10 of this embodiment can suppress the man-hour by an operator, it can reduce manufacturing cost.

  Next, operation | movement of the speed control system of the conveyance mechanism 7 with which the plate-shaped glass forming apparatus 10 is provided is demonstrated based on the flowchart shown in FIG. As shown in FIG. 8, when the drive frequency of the inverter motor 7b (motor drive frequency) is detected by the drive frequency detector 34 (S1), the camera 18 and the image processor 19 of the first detector 17 are melted. The accumulation state of the glass 5a is detected (S2). The first reference frequency storage update unit 23 updates the drive frequency of the inverter motor 7b output from the drive frequency detection unit 34 as a first reference frequency at predetermined time intervals (S3).

  On the other hand, the second reference frequency calculation unit 26 of the second detection unit 25 integrates and averages the drive frequency (motor drive frequency) of the inverter motor 7b detected by the drive frequency detection unit 34 to obtain the second reference frequency. A frequency (intercept) is calculated (S4). Furthermore, the time change rate calculation unit 30 of the second detection unit 25 includes a second reference frequency calculated by the second reference frequency calculation unit 26, a motor drive frequency detected by the drive frequency detection unit 34, and Is calculated at predetermined time intervals (S5), and the change amount (slope) of the frequency per unit time is output to the adder 33 of the second speed control unit 32.

  Here, the accumulation area determination unit 20 of the first detection unit 17 determines whether or not the molten glass accumulation 5b remains in the accumulation target area 1 (S6). When it is determined that the molten glass pool 5b does not remain in the pool target region 1 (NO in S6), the speed control selection unit 31 increases or decreases the frequency of the frequency increase / decrease unit 22 in the first speed control unit 21. And a connection with the adder 24 that adds and outputs the first reference frequency (S7).

  On the other hand, when it is determined that the molten glass pool 5b remains in the pool target region 1 (YES in S6), the speed control selection unit 31 outputs a second reference frequency. The connection to the 26 reference frequency setting units 29 is selected (S8). Next, the adder 33 of the second speed control unit 32 adds the time change rate of the frequency calculated by the time change rate calculation unit 30 to the output of the speed control selection unit 31 (S9). Further, the adder 33 of the second speed control unit 32 outputs the addition result to the drive frequency detection unit 34 as a motor drive frequency for driving the inverter motor 7b (S10).

  As described above, in the sheet glass forming apparatus 10 according to the present embodiment, the conveyance speed by the conveyance mechanism 7 controlled according to the state of the molten glass pool 5b is converted into the detection result of information corresponding to the time change. Since the correction is made based on this, it becomes possible to improve the responsiveness to fluctuations in the conveyance speed and to suppress the occurrence of a hunting phenomenon.

  Moreover, in the plate-like glass forming apparatus 10, although the amount of molten glass flowing out (the state of the molten glass pool 5b) varies depending on whether the glass material in the melting furnace (pot furnace) 8 is large or small, it has been described above. Thus, since the said conveyance speed can be adjusted substantially based on the information corresponding to the time change of the conveyance speed by the conveyance mechanism 7, even when the outflow amount of a molten glass changes gradually, the molten glass pool 5b It is possible to maintain an appropriate situation continuously. As a result, striations and distortions can be prevented from occurring in the plate-shaped glass after processing, and further, the quality of the desired thickness and width can be suppressed, such as lack of meat in the plate-shaped glass after processing. High plate-like glass can be obtained.

  Although the present invention has been specifically described above with reference to the embodiment, the present invention is not limited to the embodiment as it is, and various modifications can be made without departing from the scope of the invention at the implementation stage. For example, some constituent elements may be deleted from all the constituent elements shown in the embodiment, or a plurality of constituent elements disclosed in the above embodiments may be combined as appropriate.

  In the embodiment described above, the type of glass to be molded is not particularly illustrated, but the present invention is, for example, when molding sodium silicate glass, borate glass, fluorophosphate glass, phosphate glass, and the like. It is possible to apply. Moreover, although the pot furnace was illustrated as a melting furnace, the continuous furnace etc. which can be continuously flowed out with respect to the conveyance mechanism 7 may be applied instead of a pot furnace. Further, although an endless plate conveyor (chain conveyor) has been exemplified as a main component of the transport mechanism, the present invention is also applied to so-called slip cast molding in which glass formed into a plate shape is pulled out from the downstream side in the transport direction. It is possible to apply.

  DESCRIPTION OF SYMBOLS 1 ... Accumulation target area | region, 2 ... Deceleration area | region, 2a ... Fine adjustment deceleration area | region, 2b ... Basic adjustment deceleration area | region, 2c ... Accumulation under avoidance deceleration area | region, 3 ... Acceleration area | region, 3a ... Fine adjustment acceleration area | region, 3b ... Basic adjustment acceleration Area, 3c ... Accumulation avoidance acceleration area, 5a ... Molten glass, 5b ... Molten glass accumulation (glass accumulation), 7 ... Conveying mechanism, 7b ... Inverter motor, 7c ... Conveyor transfer roller, 8 ... Melting furnace, 9a, 9b ... guide member, 9c, 9d ... guide surface, 10 ... sheet glass forming apparatus, 11 ... first feedback processing unit, 12 ... second feedback processing unit, 14 ... rolling roller, 17 ... first detection unit, DESCRIPTION OF SYMBOLS 18 ... Camera, 19 ... Image processing part, 20 ... Accumulation area | region determination part, 21 ... 1st speed control part, 22 ... Frequency increase / decrease part, 23 ... 1st reference frequency memory | storage update part, 24 ... Adder, 25 2nd detection part, 26 ... 2nd reference frequency calculation part, 27 ... Integration part, 28 ... Average value calculation part, 29 ... Reference frequency setting part, 30 ... Time change rate calculation part, 31 ... Speed control selection part, 32 ... 2nd speed control part, 33 ... Adder, 34 ... Drive frequency detection part.

Claims (12)

A transport mechanism for transporting molten glass flowing out of the melting furnace;
A first detection unit for detecting a situation in which the molten glass flowing out accumulates on the transport mechanism;
A first speed control unit that controls a transport speed of the molten glass by the transport mechanism based on a detection result by the first detection unit;
A second detection unit for detecting information corresponding to a temporal change in the transport speed controlled by the first speed control unit;
A second speed control unit that corrects the transport speed controlled by the first speed control unit based on a detection result by the second detection unit;
A plate-shaped glass forming apparatus comprising:   The sheet glass forming apparatus according to claim 1, wherein the melting furnace is a pot furnace. The transport mechanism includes a motor serving as a drive source for the transport mechanism by rotating at a rotational speed corresponding to the drive frequency of the motor drive signal.
The second detection unit detects, as information corresponding to the time change of the transport speed, a change rate according to the passage of time of the driving frequency and an average value of the driving frequency for every constant elapsed time,
The plate-like glass forming apparatus according to claim 1 or 2. A rolling roller for rolling the molten glass conveyed by the conveying mechanism;
The first detection unit uses the molten glass as a reference in a transport direction by the transport mechanism based on a pool target area set between a position where the molten glass flows out of the melting furnace and an installation position of the rolling roller. The pool remains in the deceleration region set downstream from the pool target region, or the molten glass pool reaches the acceleration region set upstream from the pool target region. Detect that
The first speed control unit decelerates the transport speed when it is detected that the molten glass pool remains in the deceleration area, and the molten glass pool reaches the acceleration area. Accelerating the transport speed when it is detected that
The plate-shaped glass forming apparatus according to any one of claims 1 to 3. A pair of guide members each having a guide surface for restricting movement in the width direction of the molten glass conveyed by the conveyance mechanism;
The accumulation target area, the deceleration area, and the acceleration area include a position of the guide surface in at least one of the guide members,
The deceleration region and the acceleration region each have a plurality of subdivided deceleration regions and a plurality of subdivided acceleration regions further subdivided in the transport direction by the transport mechanism,
In the first detection unit, the molten glass pool remains in any of the plurality of subdivision deceleration areas, or the molten glass pool includes any of the plurality of subdivision acceleration areas. Detects that it has reached
When it is detected that the pool of molten glass remains in one of the plurality of subdivision deceleration regions, the first speed control unit remains in the subdivision deceleration region on the further downstream side. When the ratio of decelerating the conveyance speed is increased, and it is detected that the pool of molten glass has reached one of the plurality of subdivision acceleration regions, the subdivision acceleration region on the more upstream side Increase the rate of acceleration of the transport speed as it reaches
The plate-like glass forming apparatus according to claim 4. The transport mechanism includes a motor serving as a drive source for the transport mechanism by rotating at a rotational speed corresponding to the drive frequency of the motor drive signal.
In the transport direction by the transport mechanism, the first detection unit is configured to store the molten glass in a pool target region set between a position where the molten glass flows out of the melting furnace and an installation position of the rolling roller. Detect if it stays,
The second detection unit detects, as information corresponding to the time change of the transport speed, a change rate according to the passage of time of the drive frequency and an average value of the drive frequency for every constant elapsed time,
When the first detection unit detects that the molten glass pool remains in the pool target area, the first speed control unit invalidates the speed control and the second speed A speed control selection unit that selects control of the conveyance speed based on the change rate and the average value by the control unit;
The plate-shaped glass forming apparatus according to any one of claims 1, 2, 4, and 5. A transport step in which the transport mechanism transports molten glass flowing out from the melting furnace onto the transport mechanism;
A first detection step of detecting a situation in which the molten glass flowing out accumulates on the transport mechanism;
A first speed control step of controlling a transport speed of the molten glass by the transport mechanism based on a detection result of the first detection step;
A second detection step of detecting information corresponding to a temporal change in the transport speed controlled in the first speed control step;
A second speed control step for correcting the transport speed controlled in the first speed control step based on a detection result in the second detection step;
A method for forming a sheet glass, comprising:   The method for forming sheet glass according to claim 7, wherein the melting furnace is a pot furnace. The transport mechanism includes a motor serving as a drive source for the transport mechanism by rotating at a rotational speed corresponding to the drive frequency of the motor drive signal.
In the second detection step, as the information corresponding to the time change of the transport speed, a change rate according to the passage of time of the drive frequency and an average value of the drive frequency for every constant elapsed time are detected.
The method for forming a sheet glass according to claim 7 or 8. In the first detection step, in a transport direction by the transport mechanism, a pool target region set between a position where the molten glass flows out of the melting furnace and a position where a rolling roller for rolling the molten glass is installed is used as a reference. The molten glass pool remains in a deceleration region set downstream of the pool target region, or the molten glass pool is accelerated region set upstream of the pool target region Detects that it has reached
In the first speed control step, when it is detected that the molten glass pool remains in the deceleration area, the conveyance speed is reduced, and the molten glass pool reaches the acceleration area. Accelerating the transport speed when it is detected that
The method for forming a sheet glass according to any one of claims 7 to 9. The accumulation target area, the deceleration area, and the acceleration area are at least one of a pair of guide members each provided with a guide surface that regulates movement in the width direction of the molten glass conveyed by the conveyance mechanism. Including the position of the guide surface in the guide member,
The deceleration region and the acceleration region each have a plurality of subdivided deceleration regions and a plurality of subdivided acceleration regions further subdivided in the transport direction by the transport mechanism,
In the first detection step, the molten glass pool remains in one of the plurality of subdivided deceleration areas, or the molten glass pool is one of the plurality of subdivided acceleration areas. Detects that it has reached
In the first speed control step, when it is detected that the pool of molten glass remains in any one of the plurality of subdivision deceleration areas, the molten glass remains in the subdivision deceleration area on the further downstream side. When the ratio of decelerating the conveyance speed is increased, and it is detected that the pool of molten glass has reached one of the plurality of subdivision acceleration regions, the subdivision acceleration region on the more upstream side Increase the rate of acceleration of the transport speed as it reaches
The method for forming a sheet glass according to claim 10. The transport mechanism includes a motor serving as a drive source for the transport mechanism by rotating at a rotational speed corresponding to the drive frequency of the motor drive signal.
In the first detection step, in the transport direction by the transport mechanism, the molten glass pools in a pool target area set between the position where the molten glass flows out of the melting furnace and the installation position of the rolling roller. Detect if it stays,
In the second detection step, as the information corresponding to the time change of the transport speed, a change rate according to the passage of time of the drive frequency and an average value of the drive frequency for every constant elapsed time are detected,
When it is detected in the first detection step that the molten glass pool remains in the pool target area, the speed control in the first speed control step is invalidated, and the second A speed control selection step of selecting control of the transport speed based on the change rate and the average value in the speed control step;
The method for forming a sheet glass according to any one of claims 7, 8, 10 and 11.

Images