TW202010715A - Method for manufacturing glass article - Google Patents

Abstract

A method for manufacturing a glass article which comprises: a continuous formation process for, while continuously feeding a glass starting material 4 onto a molten glass 2 pooled in a furnace 1, melting the starting material 4 to thereby continuously form fresh molten glass 2 and, at the same time, flowing out the molten glass 2 from the furnace 1 through a pipe 5 having an inner peripheral surface 5a configured of platinum or a platinum alloy; and a set-up process for setting up the furnace 1 until the continuous formation process becomes executable, wherein the set-up process involves a temperature rising step for rising the temperature in the furnace 1 from room temperature using combustion burners 7 and 8 and, in the temperature rising step, heating with the combustion burners 7 and 8 is performed while reducing contact between the atmosphere in the furnace 1 and the inner peripheral surface 5a of the pipe 5.

Description

Glass article manufacturing method

The present invention relates to a method of manufacturing a glass article. The method of manufacturing a glass article includes: a step of continuously generating molten glass as a raw material of the glass article using a glass melting furnace; and a step of starting the furnace to a state where the step can be performed .

As is well known, glass articles represented by glass plates, glass tubes, glass fibers, and the like are manufactured by forming molten glass produced by melting glass raw materials into a predetermined shape. Here, Patent Document 1 discloses an example of a method of continuously generating molten glass using a glass melting furnace.

In the method disclosed in this document, while the glass raw material is continuously supplied to the molten glass stored in the glass melting furnace, the glass raw material is melted to continuously generate new molten glass, and the molten glass is passed through the outflow path (in this The furnace throat in the literature) flows out of the furnace. Furthermore, the inner peripheral surface of the outflow passage is usually made of platinum or platinum alloy. [Prior Art Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2003-183031

[Problems to be solved by the invention] In addition, when the glass melting furnace is operated, it is necessary to start the furnace to a state where molten glass can be continuously produced. When the furnace is started, in order to raise the temperature in the furnace from normal temperature, an air burner that mixes and burns a gas fuel such as natural gas with air or an oxygen burner that mixes and burns a gas fuel with oxygen is often used. By heating with these burners, when the temperature in the furnace rises to a temperature at which the glass raw material can be melted, the glass raw material is started to be supplied into the furnace. Along with this, the glass raw material melts, and the molten glass is gradually stored in the furnace.

However, when the glass melting furnace of the above aspect is started, the following problems may occur.

That is, when an air burner or an oxygen burner is used in order to increase the temperature in the glass melting furnace, the air or oxygen is continuously fed into the furnace, and accompanying this, the environment in the furnace containing oxygen Gas inevitably flows into the outflow path. As a result, there arises a problem that the platinum or platinum alloy constituting the inner peripheral surface of the outflow path is oxidized or volatilized.

In view of the above circumstances, the technical problem of the present invention is that, when manufacturing a glass article, when the temperature in the glass melting furnace is increased by the heating of the burner and the furnace is started, the flow path constituting the molten glass is suppressed as much as possible Oxidation or volatilization of platinum or platinum alloy on the inner peripheral surface. [Means to solve the problem]

The present invention for solving the above-mentioned problems is a method of manufacturing a glass article, including a continuous generation step of continuously supplying glass raw materials to molten glass stored in a glass melting furnace while melting the glass raw materials to continuously generate new Molten glass, and causing the molten glass to flow out of the glass melting furnace through an outflow passage having an inner peripheral surface composed of platinum or a platinum alloy; and a start-up step to start the glass melting furnace to a state where a continuous generation step can be performed, and The manufacturing method of the glass article is characterized in that the starting step includes: a temperature rising step of raising the temperature in the glass melting furnace from normal temperature by using a burner; and a raw material supply starting step of starting to supply the glass raw material into the glass melting furnace. In the step, the burner is used for heating while reducing the contact between the ambient gas in the glass melting furnace and the inner peripheral surface of the outflow passage.

According to this method, in the temperature raising step, with the contact between the ambient gas in the glass melting furnace and the inner peripheral surface of the outflow passage reduced, the burner is used for heating, and the temperature in the furnace rises from normal temperature. With this, even in the case where the ambient air flow into the furnace containing oxygen fed into the furnace with the use of the burner enters or exits the outflow path, the inner peripheral surface constituting the outflow path can be suppressed as much as possible Oxidation or volatilization of platinum or platinum alloys.

In the above method, it is preferable to use a shielding material to prevent the ambient gas in the glass melting furnace from contacting the inner peripheral surface of the outflow passage.

By using the shielding material to prevent the ambient gas in the glass melting furnace from contacting the inner peripheral surface of the outflow passage, it is possible to stably reduce the contact between the ambient gas in the glass melting furnace and the inner peripheral surface of the outflow passage.

In the above method, as the shielding material, glass material is preferably used.

By using the glass material to prevent the ambient air in the furnace from contacting the inner peripheral surface of the outflow passage, the following effects can also be obtained. That is, a member other than glass (for example, a metal member, a refractory, etc.) may be used as the shielding material, but in this case, an operation of removing the shielding material occurs. In addition, the shielding material may be mixed into the molten glass to cause defects. If a glass material is used, as the temperature in the furnace rises, the glass material soon melts to become molten glass, and the molten glass obtained by melting the glass raw material is sent to the downstream step. Therefore, if a glass material is used as the shielding material, there is no need to remove the shielding material, and the possibility that the shielding material is mixed into the molten glass to cause a defect may be excluded.

In the above method, as the glass material, it is preferable to use a glass plate covering the opening on the upstream end of the outflow path.

In this way, by the glass plate covering the opening at the upstream end of the outflow path, it is possible to reliably prevent the ambient air flow in the furnace containing oxygen from entering the outflow path. This is more advantageous in suppressing oxidation or volatilization of platinum or a platinum alloy constituting the inner peripheral surface of the outflow channel as much as possible.

In the above method, it is preferable that the composition of the glass material is the same as the composition of the molten glass.

In this way, the composition of the molten glass can be prevented from changing due to the glass material, so it is advantageous in using molten glass.

In the method described above, it is preferable that the glass melting furnace includes an electrode movable between an entrance position into the furnace and a retreat position retreating from the furnace, and in the continuous generation step, the electrode located at the entrance position is energized and heated In the temperature rising step, the cover member covers the tip of the electrode located at the retreat position to prevent the ambient gas in the glass melting furnace from contacting the electrode, and the heater is used for heating.

In this way, by covering the electrode with the cover member, the contact between the electrode and the ambient gas in the furnace can be reduced, and the electrode can be protected from oxidation.

In the method, the glass melting furnace may be used as the first glass melting furnace, and the outflow path may be used as the first outflow path, and the first glass melting furnace and the first glass may be removed through the first outflow path. The second glass melting furnace into which the molten glass flowing out of the melting furnace flows in is connected, and in the second glass melting furnace, a temperature increasing step in which the temperature in the second glass melting furnace is raised from normal temperature by a burner is performed. In the second glass melting furnace In the temperature raising step, the shielding material is used to prevent the ambient gas in the second glass melting furnace from contacting the inner peripheral surface of the first outflow path, and the ambient gas in the second glass melting furnace and the flow of molten glass to the second In the state where the inner peripheral surface of the second outflow passage outside the glass melting furnace made of platinum or platinum alloy is in contact, it is heated by a burner.

In this way, not only in the first glass melting furnace but also in the second glass melting furnace, the oxidation or volatilization of the platinum or platinum alloy constituting the inner peripheral surface of the outflow path (second outflow path) can be suppressed as much as possible.

In the method, in the continuous production step, it is preferable to heat the molten glass stored in the glass melting furnace only by energized heating.

In this way, the ambient gas in the glass melting furnace can be dried compared with the case where the heating using a burner and the energized heating are used in combination. Thereby, it is easy to prevent the moisture in the ambient air in the furnace from dissolving into the molten glass, and it is easy to reduce the β-OH value of the manufactured glass article. As a result, the compaction when heating the glass article can be reduced, and a glass article suitable for an alkali-free glass substrate for a display can be obtained.

Here, the “alkali-free glass” refers to glass that does not substantially contain an alkali component (alkali metal oxide), and specifically refers to glass having a weight ratio of the alkali component of 3000 ppm or less. Furthermore, the weight of the alkali component is preferably 1000 ppm or less, more preferably 500 ppm or less, and most preferably 300 ppm or less. [Effect of invention]

According to the present invention, when manufacturing a glass article, when the temperature in the glass melting furnace is raised by the heating of the burner and the furnace is started, the platinum or platinum alloy constituting the inner peripheral surface of the outflow path of the molten glass can be suppressed as much as possible Oxidation or volatilization.

<First embodiment> Hereinafter, a method of manufacturing a glass article according to a first embodiment of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show a state where a continuous generation step is performed in a glass melting furnace 1 (hereinafter simply referred to as furnace 1 ).

In the continuous production step, while the temperature in the furnace 1 (molten glass) is maintained at the operating temperature (for example, 1450°C to 1550°C), the molten glass 2 stored in the furnace 1 is electrically heated by the electrode 3 While sequentially melting the glass raw materials 4 continuously supplied to the surface 2a of the molten glass 2 to continuously generate new molten glass 2 and flowing the molten glass 2 to the furnace 1 through the tube 5 as the outflow path (first outflow path) outer. In this continuous generation step, the molten glass 2 is heated only by the energization heating of the electrode 3.

The molten glass 2 produced in the continuous production step is sent to the downstream step including the forming step, and the glass article (eg, glass plate, glass tube, glass fiber, etc.) is manufactured through the process of forming the molten glass 2 in the downstream step. ).

The furnace 1 used in this embodiment has a rectangular cross-sectional shape in plan view. This furnace 1 has a front wall 1a located at the upstream end in the flow direction T of the glass raw material 4 in the furnace 1, a rear wall 1b located at the downstream end, a pair of side walls 1c, 1d, a top wall 1e, and a bottom wall 1f. The furnace walls 1a to 1f are each composed of a refractory (in this embodiment, high-zirconia electroformed refractory bricks).

A plurality of (three in this embodiment) screw feeders 6 for supplying glass raw materials 4 into the furnace 1 are arranged in parallel on the front wall 1 a. Each screw feeder 6 is inserted into the opening 1aa formed in the front wall 1a without a gap. Furthermore, tin oxide is added as a clarifier to the glass raw material 4 supplied from the screw feeder 6.

Here, in the present embodiment, the screw feeder 6 is used to supply the glass raw material 4, but a feeder other than the screw feeder 6 may be used. As an example of the feeder, a vibrating feeder, a pusher, a blanket feeder, etc. can also be used. From the viewpoint of improving the airtightness in the furnace 1, it is preferable to use a screw feeder 6 or a vibrating feeder. In addition, in this embodiment, a plurality of screw feeders 6 are used, but the number of screw feeders 6 may be only one.

A tube 5 for flowing out the molten glass 2 is arranged on the rear wall 1b. The inner peripheral surface 5a of the tube 5 is made of platinum or platinum alloy.

On the side wall 1c and the side wall 1d, a burner pair 9 composed of a pair of an air burner 7 and an oxygen burner 8 is arranged. In this embodiment, three pairs of burner pairs 9 are arranged on the side wall 1c. , Two pairs of burners 9 are arranged on the side wall 1d. Furthermore, in this embodiment, the air burner 7 and the oxygen burner 8 are arranged in pairs, but the number of the air burner 7 and the oxygen burner 8 may be different. In addition, the air burner 7 and the oxygen burner 8 may be disposed on the top wall 1e. In the execution of the continuous generation step of the present embodiment, in each of the five burner pairs 9 in total, both the air burner 7 and the oxygen burner 8 are in a stopped state.

The air burner 7 is a burner that mixes gas fuel such as natural gas with air and burns it. On the other hand, the oxygen burner 8 is a burner that mixes and burns gaseous fuel with oxygen.

As shown by the two-dot chain line in FIG. 2, the two burners 7 and 8 can respectively inject flames 7 a and 8 a from the side wall 1 c (side wall 1 d) side to the opposite side wall 1 d (side wall 1 c) side. Furthermore, the thermal power of the oxygen burner 8 is greater than the thermal power of the air burner 7. On the other hand, the flame 7a injected by the air burner 7 is wider than the flame 8a injected by the oxygen burner 8 in plan view. Furthermore, in the present embodiment, the air burner 7 can be detached from the side wall 1c (side wall 1d) in a state where the operation is stopped. The oxygen burner 8 can also be detached from the side wall 1c (side wall 1d) in a state where the operation is stopped.

The electrode 3 arranged on the bottom wall 1f is formed in a rod shape. The electrode 3 can be in the entry position (the position where the electrode 3 is located in FIG. 1) from the bottom wall 1f into the furnace 1 and the retreat position retracted from the furnace 1 (the electrode 3 in the later-mentioned FIG. 3 is located Position). The electrode 3 is made of molybdenum, for example.

In the execution of the continuous generation step, the molten glass 2 is heated by the electrode 3 at the entry position and in the state of being immersed in the molten glass 2 in the furnace 1. By adjusting the voltage applied to the electrode 3, the energy (heat energy given to the molten glass 2) generated by the electrode 3 can be adjusted. Further, as the electrode 3 heats the molten glass 2, the glass raw material 4 on the surface 2 a of the molten glass 2 is indirectly heated and melted. With this, new molten glass 2 is sequentially produced.

Here, in the present embodiment, the molten glass 2 is heated by the rod-shaped electrode 3, but in addition to the rod-shaped electrode 3, or instead of the rod-shaped electrode 3, it may be arranged by a pair of side walls The plate-shaped electrode or the bulk-shaped electrode on 1c and 1d heats the molten glass 2.

In this embodiment, when the furnace 1 is started to a state where the continuous generation step can be executed, the following start-up step is performed.

In the startup step, the first temperature increase step (Figure 3), the second temperature increase step (Figure 5), the raw material supply start step (Figure 6), and the energization heating start step (Figure 8), where the first temperature increase step is The step of raising the temperature in the furnace 1 from the normal temperature (especially the temperature without cooling or heating, for example, 20±15°C) by the air burner 7, and the second heating step is to make the temperature in the furnace 1 by the oxygen burner 8 The temperature rising step, the raw material supply start step is a step to start supplying the glass raw material 4 into the furnace 1, and the energization heating start step is a step to start the energization heating of the molten glass 2 stored by melting the glass raw material 4 and storing it. In this embodiment, both the first temperature increase step and the second temperature increase step constitute a temperature increase step.

First, as preparations for performing the start-up step, before the start of the first temperature-raising step, as shown in FIG. 3, the electrode 3 is positioned at the retreat position, and then the first glass plate 10 (cover member) is placed on the bottom of the furnace 1 On the wall 1f. The first glass plate 10 is located directly above the electrode 3, so the front end (upper end) of the electrode 3 is covered by the first glass plate 10. In this way, the electrode 3 is protected by the first glass plate 10. The state in which the electrode 3 is covered by the first glass plate 10 continues until the first glass plate 10 melts as the temperature in the furnace 1 rises. With this, during the period from the start of the first temperature increase step to the melting of the first glass plate 10, the contact of the oxygen-containing ambient gas in the furnace 1 with the electrode 3 is prevented, and the oxidation of the electrode 3 is avoided as much as possible. In addition, the space formed between the first glass plate 10 and the electrode 3 is filled with a plurality of glass (not shown) formed in a block shape.

Here, in this embodiment, when the electrode 3 and the furnace 1 are separated, the tip of the electrode 3 is covered with the first glass plate 10, but it is not limited to this. Instead of the first glass plate 10, for example, the tip of the electrode 3 may be covered with glass dust. The first glass plate 10 and the glass chips preferably use glass plates and glass chips containing glass having the same composition as the molten glass 2 produced by melting the glass raw material 4, and more preferably use the same composition as the molten glass 2 Glass plate and glass shavings.

Furthermore, before the start of the first temperature increase step, the opening 5 ba of the upstream end 5 b of the tube 5 is covered with the second glass plate 11 and the third glass plate 12 as glass materials. In this way, the inside of the tube 5 and the inside of the furnace 1 are separated by the two glass plates 11 and 12. The state where the inside of the tube 5 is separated from the inside of the furnace 1 continues until the two glass plates 11 and 12 melt as the temperature in the furnace 1 rises. By this, during the period from the start of the first temperature raising step to the melting of the two glass plates 11 and 12, the gas in the furnace 1 and the tube 5 are prevented from communicating with each other, and the atmosphere containing oxygen in the furnace 1 and the tube 5 are prevented The contact of the inner peripheral surface 5a. In this way, the oxidation of platinum constituting the inner peripheral surface 5a of the tube 5 is avoided as much as possible. When the molten glass 2 is alkali-free glass, it is preferable to use a glass plate containing alkali-free glass for both glass plates 11 and 12.

Hereinafter, the specific form in which the second glass plate 11 and the third glass plate 12 are provided will be described with reference to FIG. 4. In this embodiment, the case where the flow path of the tube 5 has a rectangular cross section will be described as an example. Of course, the present invention can be applied even when the cross section of the flow path of the tube 5 has a shape other than a rectangle, for example, a circle, an ellipse, or a polygon.

As shown in FIG. 4, one second glass plate 11 is provided, and two third glass plates 12 are provided so as to sandwich the second glass plate 11. In this embodiment, both glass plates 11 and 12 have a rectangular shape.

The second glass plate 11 is installed in a state of standing on the upstream side end portion 5b (the rear wall 1b of the furnace 1) of the tube 5. The main surface (front and back) of the second glass plate 11 is in a state of being inclined with respect to the vertical line. The width dimension (width dimension in the horizontal direction) of the second glass plate 11 is the same as the width dimension of the tube 5. The upper edge of the second glass plate 11 is located above the upper portion of the upstream end 5b. On the other hand, the lower edge of the second glass plate 11 is in contact with the bottom wall 1f of the furnace 1.

The two third glass plates 12 are installed in an upright state in such a manner that their main surfaces are in contact with the end surfaces in the width direction of the second glass plate 11 in a substantially upright posture. The upper edges of these third glass plates 12 are located above the upper portion of the upstream end 5b. On the other hand, the lower edge of the third glass plate 12 is in contact with the bottom wall 1f of the furnace 1. One of the pair of side portions of the third glass plate 12 extending in the vertical direction is in contact with the rear wall 1b of the furnace 1.

Although not shown, it is preferable to include a gap formed between the end surface in the width direction of the second glass plate 11 and the main surface of the third glass plate 12, and the gap leading from the furnace 1 to the tube 5 as the glass The glass plate or glass chips of the material are blocked. In addition, since these gaps are required to be as small as possible, the glass raw material 4 may be used for clogging. However, from the viewpoint of avoiding the possibility that a part of the components of the raw material 4 volatilize before melting, it is preferable to use a glass material. In addition to the rectangular shape, the surface shapes of the second glass plate 11 and the third glass plate 12 may be, for example, trapezoidal or triangular, or glass plates having different surface shapes may be used in combination.

Furthermore, in the present embodiment, the outer peripheral surface of the upstream end 5b is in a state of being in contact with the rear wall 1b without being exposed to the ambient air in the furnace 1, but the outer peripheral surface of the upstream end 5b may be The state in which the ambient air in the furnace 1 is exposed. In this case, the outer peripheral surface of the upstream end 5b may be included. During the execution of the continuous generation step, all the tubes 5 that are in contact with the molten glass 2 are covered with glass shavings, glass plates, glass plates, glass raw materials 4, and the like. Parts (parts made of platinum or platinum alloy). For example, the upper surface of the outer peripheral surface of the upstream end 5b may be covered with a glass plate, and the side surfaces of the outer peripheral surface of the upstream end 5b may be covered with the two third glass plates 12 respectively. Furthermore, the inner peripheral surface 5a of the tube 5 may be covered with the glass raw material 4 filled in the tube 5.

Here, in this embodiment, before the start of the first temperature raising step, the front end of the electrode 3 is covered with the first glass plate 10, and the opening of the upstream end 5b is covered with the second glass plate 11 and the third glass plate 12 5ba, but not limited to this, these operations may also be performed at the beginning of the first heating step.

As described above, after the preparation for performing the start-up step is completed, then, as shown in FIG. 3, the flame 7a is injected by operating the air burner 7 to start the first temperature-raising step. Furthermore, in this embodiment, at the start of the first temperature raising step, the supply of glass raw material 4 into the furnace 1 is not started except for clogging of the first to third glass plates 10, 11, 12 and both glass plates The glass sheets or glass chips in the gap between 11 and 12 are in a state where the molten glass 2 and the glass raw material 4 are not present in the furnace 1.

After the start of the first temperature raising step, when the temperature in the furnace 1 (ambient gas temperature of the top wall 1e) rises to any temperature within the range of 700°C to 900°C, as shown in FIG. 5, the first temperature raising step is performed Switch to the second heating step. For example, the operation of the air burner 7 is stopped in sequence, and the operation of the oxygen burner 8 is started in sequence. The start of the first operation of the oxygen burner 8 is the start of the second temperature increase step.

After switching from the first temperature raising step to the second temperature raising step, when the temperature in the furnace 1 rises to a temperature at which the glass raw material 4 can be melted (hereinafter, expressed as a melting temperature), as shown in FIG. The feeder 6 is operated to start supplying the glass raw material 4 into the furnace 1, and the raw material supply start step is performed. Part or all of the glass raw material 4 may be glass chips.

In addition, the raw material supply start step may be performed simultaneously with the end of the switching from the first temperature increase step to the second temperature increase step as long as the temperature in the furnace 1 rises to the melting temperature. On the other hand, the raw material supply start step may be performed at any time before the temperature in the furnace 1 rises to the melting temperature. However, from the viewpoint of avoiding the possibility that the components contained in the glass raw material 4 volatilize and disappear before the raw material 4 is melted, it is preferable to perform the raw material supply start step after the temperature in the furnace 1 rises to the meltable temperature.

After the raw material supply start step, as shown in FIG. 7, the glass raw materials 4 supplied into the furnace 1 are sequentially melted, and the molten glass 2 is stored in the furnace 1. Thereby, the height position of the surface 2a of the molten glass 2 in the furnace 1 gradually rises. Furthermore, as indicated by the two-dot chain line in FIG. 7, the first glass plate 10 that separates the furnace 1 from the electrode 3, the second glass plate 11 that separates the furnace 1 from the tube 5, and the third glass The plate 12 melts in sequence as the temperature in the furnace 1 rises.

Then, after the height position of the surface 2a of the molten glass 2 reaches a predetermined reference position, as shown in FIG. 8, the electrode 3 is moved from the retreat position to the entry position. Then, by applying a voltage to the electrode 3, an electric heating start step is performed. The temperature in the furnace 1 (melted glass) at this time is, for example, in the range of 1300°C to 1600°C.

Then, as shown in FIG. 9, when the height position of the surface 2a of the molten glass 2 reaches the position when the continuous generation step is performed, and the temperature in the furnace 1 becomes substantially uniform at the operating temperature, in order to maintain the temperature in the furnace 1 To stop the operation of the oxygen burner 8 in sequence. When all the oxygen burners 8 are stopped, the start-up step ends. Then, the continuous generation step is started in the furnace 1.

Hereinafter, the main operation and effect of the method of manufacturing a glass article according to the embodiment of the present invention will be described.

In the method for manufacturing a glass article of the first embodiment, in the first and second temperature raising steps, the contact between the ambient gas in the furnace 1 and the inner peripheral surface 5a of the tube 5 is prevented by the two glass plates 11 and 12 In a state where the temperature is increased by the air burner 7 or the oxygen burner 8, the temperature in the furnace 1 rises from normal temperature. Thereby, it is possible to avoid the flow of ambient air into the tube 5 in the furnace 1 containing oxygen sent into the furnace 1 along with the use of the two burners 7 and 8. As a result, the oxidation or volatilization of the platinum or platinum alloy constituting the inner peripheral surface 5a of the tube 5 can be suppressed as much as possible.

<Second embodiment> Hereinafter, a method of manufacturing a glass article according to a second embodiment of the present invention will be described with reference to FIG. 10. In addition, in the description of the second embodiment, the elements that are substantially the same as those already described in the first embodiment are denoted by the same symbols, and repeated explanations are omitted. Only the first embodiment is described. The different points of the method will be explained.

The second embodiment differs from the first embodiment in that the furnace 1 is used as the first glass melting furnace 13 (hereinafter referred to as the first furnace 13), and the tube 5 is used as the first tube 14, based on this In the above, the first furnace 13 is connected to the second glass melting furnace 15 (hereinafter, expressed as the second furnace 15) into which the molten glass 2 flowing out of the first furnace 13 flows via the first tube 14. The second furnace 15 has the same structure as the first furnace 13 except that the screw feeder 6 is not provided. In addition, the first tube 14 of the present embodiment is arranged in a posture in which the longitudinal direction is horizontal, but it may be arranged in a posture in which the longitudinal direction is inclined so that it becomes higher as it moves away from the first furnace 13. In this embodiment, the bottom wall 1f of the first furnace 13 and the bottom wall 1f of the second furnace 15 have the same height. However, the bottom wall 1f of the second furnace 15 may be arranged at the bottom of the first furnace 13. The position where the wall 1f is high, or the bottom wall 1f of the second furnace 15 may be arranged lower than the bottom wall 1f of the first furnace 13.

In the second furnace 15, the first and second temperature raising steps of raising the temperature in the second furnace 15 from the normal temperature by the air burner 7 or the oxygen burner 8 are also performed. In this embodiment, the first and second temperature-raising steps of the second furnace 15 are started simultaneously with the execution of the first and second temperature-raising steps in the first furnace 13, but it does not necessarily need to be started at the same time or performed synchronously. There may be some time lag. The first and second temperature raising steps in the second furnace 15 can be performed under the same conditions as the first and second temperature raising steps in the first furnace 13.

In the first and second temperature raising steps in the second furnace 15, the opening 5ca of the downstream end 5c in the first tube 14 may not be covered with a glass plate, but in order to further prevent the ambient gas and As shown in FIG. 10, the contact of the inner circumferential surface 5 a of the first tube 14 preferably covers the downstream end 5 c of the first tube 14 with the second glass plate 11 and the third glass plate 12 as glass materials. Open 5ca. The form of the opening 5ca covering the downstream end 5c is the same as the form of the opening 5ba covering the upstream end 5b.

In addition, in the first and second temperature raising steps in the second furnace 15, the ambient gas in the second furnace 15 and the second outflow path for the molten glass 2 to flow out of the second furnace 15 are prevented The inner peripheral surface 5a of the tube 16 is in contact. For this reason, the opening 5ba of the upstream end 5b of the second tube 16 is covered with the second glass plate 11 and the third glass plate 12 that are glass materials. The form of the opening 5ba covering the upstream end 5b of the second tube 16 is the same as the form of the opening 5ba covering the upstream end 5b of the first tube 14.

In addition, the present invention is not limited to the structure of the above-mentioned embodiment, nor is it limited to the above-mentioned effect. The present invention can be variously modified without departing from the gist of the present invention.

In the above embodiment, in the continuous generation step, only the heating of the electrode 3 is used to continuously generate the molten glass, but it is not limited to this, and the heating of the burners 7 and 8 may be used in combination. In addition, in the continuous production step when the first furnace 13 and the second furnace 15 constitute a glass melting furnace as in the second embodiment, the heating of the electrode 3 and the burner 7 may be used in the first furnace 13 in combination. For the heating of 8, only the heating of the burners 7, 8 is used in the second furnace 15. In the case of using the heating of the burners 7 and 8 in the continuous generation step, it is preferable to use the oxygen burner 8. From the viewpoint of reducing the β-OH value of the manufactured glass article, it is preferable to use a single melting furnace 1 as in the first embodiment, and to continuously generate melting by heating only the electrode 3 in the continuous production step glass.

1: glass melting furnace 1a: front wall 1aa: opening 1b: rear wall 1c, 1d: side wall 1e: top wall 1f: bottom wall 2: molten glass 2a: surface 3: electrode 4: Glass raw materials 5: Tube 5a: inner surface 5b: upstream end 5ba, 5ca: opening 5c: downstream end 6: screw feeder 7: Air burner 7a, 8a: flame 8: Oxygen burner 9: burner pair 10: The first glass plate 11: Second glass plate 12: third glass plate 13: The first glass melting furnace 14: The first tube 15: Second glass melting furnace 16: Second tube T: flow direction

FIG. 1 is a longitudinal cross-sectional view showing a continuous generation step in the method of manufacturing a glass article according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a continuous generation step in the method of manufacturing a glass article according to the first embodiment of the present invention. 3 is a longitudinal cross-sectional view showing a start-up step in the method of manufacturing a glass article according to the first embodiment of the present invention. 4 is a perspective view showing a start-up procedure in the method of manufacturing a glass article according to the first embodiment of the present invention. 5 is a longitudinal cross-sectional view showing a start-up step in the method of manufacturing a glass article according to the first embodiment of the present invention. 6 is a longitudinal cross-sectional view showing a starting step in the method of manufacturing a glass article according to the first embodiment of the present invention. 7 is a longitudinal cross-sectional view showing a start-up step in the method of manufacturing a glass article according to the first embodiment of the present invention. 8 is a longitudinal cross-sectional view showing a start-up step in the method of manufacturing a glass article according to the first embodiment of the present invention. 9 is a longitudinal cross-sectional view showing a start-up step in the method of manufacturing a glass article according to the first embodiment of the present invention. 10 is a longitudinal cross-sectional view showing a start-up step in the method of manufacturing a glass article according to the second embodiment of the present invention.

1: glass melting furnace

1b: rear wall

1c: side wall

1f: bottom wall

5: Tube

5a: inner surface

5b: upstream end

5ba: opening

11: Second glass plate

12: third glass plate

Claims (8)

A method for manufacturing a glass article, comprising: a continuous generation step of continuously supplying glass raw materials to molten glass stored in a glass melting furnace, while melting the glass raw materials to continuously generate new molten glass, and melting glass Flowing out of the glass melting furnace through an outflow passage having an inner peripheral surface composed of platinum or a platinum alloy; and a starting step to start the glass melting furnace to a state where the continuous generation step can be performed, and the The method of manufacturing a glass article is characterized by The start-up step includes: a temperature increase step of increasing the temperature in the glass melting furnace from normal temperature by using a burner; and a raw material supply start step of starting to supply the glass raw material into the glass melting furnace, In the temperature increasing step, the burner is used for heating while reducing the contact between the ambient gas in the glass melting furnace and the inner peripheral surface of the outflow passage. The method for manufacturing a glass article according to item 1 of the patent application range, wherein the shielding material is used to prevent the ambient gas in the glass melting furnace from contacting the inner peripheral surface of the outflow passage. The method for manufacturing a glass article according to item 2 of the patent application scope, wherein a glass material is used as the shielding material. The method for manufacturing a glass article according to claim 3, wherein as the glass material, a glass plate covering an opening on the upstream end of the outflow path is used. The method for manufacturing a glass article according to item 3 or item 4 of the patent application scope, wherein the composition of the glass material is the same as the composition of the molten glass. The method for manufacturing a glass article according to any one of the first to fifth patent application scopes, wherein the glass melting furnace includes a movable position between an entrance position into the furnace and a retreat position to retreat from the furnace Of electrodes, In the continuous generation step, the electrodes located at the entry position are heated by electricity, In the temperature raising step, the cover is used to cover the tip of the electrode at the retreat position to prevent the ambient gas in the glass melting furnace from contacting the electrode, and the burner is used heating. The method for manufacturing a glass article according to any one of claims 1 to 6, wherein the glass melting furnace is used as a first glass melting furnace and the outflow path is used as a first outflow path, Connecting the first glass melting furnace to the second glass melting furnace into which the molten glass flowing out of the first glass melting furnace flows through the first outflow path, In the second glass melting furnace, a temperature increasing step of raising the temperature in the second glass melting furnace from normal temperature by using a burner is performed, In the temperature increasing step in the second glass melting furnace, the shielding material is used to prevent the ambient gas in the second glass melting furnace from contacting the inner peripheral surface of the first outflow path, and to prevent the first The burner is used in a state where the ambient gas in the second glass melting furnace is in contact with the inner peripheral surface made of platinum or platinum alloy for the second outflow path for the molten glass to flow out of the second glass melting furnace Perform heating. The method for manufacturing a glass article according to any one of claims 1 to 7, wherein in the continuous generation step, the molten glass stored in the glass melting furnace is heated by energization only Perform heating.

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