JP6834894B2 - Tube glass manufacturing equipment and tube glass manufacturing method - Google Patents

Description

The present invention relates to a tube glass manufacturing apparatus and a tube glass manufacturing method.

As a method for manufacturing tube glass used for fluorescent lamps and the like, for example, in Patent Document 1, molten glass is supplied from a supply unit to a molded body rotating around an axis in the vertical direction, and the supplied molten glass is supplied. It is disclosed that a tube glass is manufactured by flowing down the glass from a molded body.

In the document, the molded body is provided with an upper surface that receives the molten glass supplied during rotation, and the molten glass flows down from the outer peripheral edge of the upper surface. Such a configuration has an advantage that the replacement time of the molded body can be shortened and the diameter of the tube glass can be increased.

Japanese Unexamined Patent Publication No. 2016-44123

By the way, in the manufacturing method disclosed in Patent Document 1, in order to improve the quality such as the outer diameter and the thickness of the tube glass, it is important to reduce the thickness variation of the molten glass flowing down the molded product as much as possible. Become.

However, the viscosity of the molten glass supplied may change due to temperature fluctuations until the molded product is supplied, and the amount of molten glass supplied to the molded product may fluctuate per unit time. When the supply amount of the molten glass fluctuates in this way, the thickness of the molten glass tends to fluctuate on the molded body.

An object of the present invention is to reduce fluctuations in the thickness of molten glass on a molded product as much as possible and to produce high-quality tube glass.

The present invention, which was devised to solve the above problems, includes a supply unit for supplying molten glass and a molded body that rotates around an axis in the vertical direction while being supplied with molten glass from the supply unit, and is rotating. It is a tube glass manufacturing device that manufactures tube glass by flowing molten glass from the molded body, and the molded body has one saucer portion that receives the molten glass between the inner and outer peripheral edges or a vertical interval. Each of the one or more saucers is configured to have a conical shape that is gradually lowered as it moves from the inner peripheral edge to the outer peripheral edge, and the molten glass flows down from the outer peripheral edge. The diagonal lengths between the inner and outer edges of each saucer are L ₁ (mm), L ₂ (mm), ..., L _n (mm), respectively, in order from the top tray. When the tilt angle of the saucer with respect to the horizontal plane is α ₁ (°), α ₂ (°), ..., α _n (°)
L ₁ / α ₁ + L ₂ / α ₂ + ... + L _n / α _n ≧ 2… (1)
It is characterized by satisfying the relationship. However, L _n is the length of the hypotenuse of the saucer portion in the _{nth stage (bottom stage) from the top, and α n} is the inclination angle of the saucer portion in the nth stage (bottom stage) from the top. n is an integer of 1 or more, and includes the case where only one saucer portion is provided (when n = 1), that is, the case where only the uppermost saucer portion is provided. According to such a configuration, the relationship between the hypotenuse (generatrix) length and the inclination angle is optimized in each of the one or a plurality of saucer portions. Specifically, if the relationship of the above equation (1) is satisfied, even if the inclination angle of the saucer portion becomes large and the moving speed of the molten glass to the outer peripheral edge side increases, the hypotenuse of the saucer portion according to the moving speed. The length is also large enough. Therefore, since a sufficient staying time of the molten glass can be secured on the saucer portion, even if the supply amount of the molten glass fluctuates per unit time, the thickness of the molten glass is leveled in the process of moving the saucer portion. ..

In the above configuration, the top tray is
L ₁ / α ₁ ≧ 2… (2)
It is preferable to satisfy the above relationship. Since the temperature of the molten glass is high and the viscosity is low in the uppermost tray, the effect of leveling the thickness of the molten glass is the highest. Therefore, it is preferable that the uppermost tray portion satisfies the above formula (2) in order to reduce the thickness variation of the molten glass.

In the above configuration, the inclination angle α ₁ of the uppermost tray portion is preferably 15 ° or less. By doing so, the inclination angle of the uppermost tray portion becomes very small, so that the moving speed of the molten glass on the saucer portion becomes sufficiently slow. Therefore, the effect of leveling the thickness of the molten glass in the uppermost tray portion becomes higher.

In the above configuration, the molded body is provided with a tubular side surface portion that guides the molten glass flowing down from the outer peripheral edge at a position below the outer peripheral edge, and the side surface portion is a diaphragm whose diameter is gradually reduced downward at the lower end portion. It is preferable that one portion or a plurality of portions are provided at intervals in the vertical direction. In this way, after the thickness of the molten glass is leveled at the saucer portion, the molten glass can be squeezed to a predetermined diameter, so that glass tubes having various diameters smaller than the diameter of the outer peripheral edge of the saucer portion can be manufactured. It will be easier.

In this case, the inclination angle of the lowermost diaphragm portion with respect to the vertical surface is preferably 15 ° or less. In the lowermost drawn portion, when the molten glass flows downward, the diameter of the molded body becomes smaller and the thickness of the glass increases. Therefore, if the inclination angle of the lowermost drawing portion with respect to the vertical surface is too large, the flow of the molten glass may be disturbed due to a sudden change in the glass thickness in the drawing portion. When such a phenomenon occurs, it can be one of the factors that cause the thickness variation of the molten glass. Therefore, it is preferable that the inclination angle of the lowermost throttle portion is within the above numerical range to suppress a sudden change in the flow direction of the molten glass in the lowermost throttle portion.

The present invention, which was devised to solve the above problems, supplies molten glass from a supply unit to a molded body rotating around an axis in the vertical direction, and causes the molten glass to flow down from the molded body to make a tube glass. The molded body is provided with one or a plurality of saucer portions for receiving the molten glass at intervals in the vertical direction, and each of the one or a plurality of saucer portions is outside from the inner peripheral edge. It forms a conical shape that is gradually lowered as it moves to the peripheral edge, satisfies the above formula (1) in the same manner, and receives the molten glass between the inner peripheral edge and the outer peripheral edge of each of the one or more saucer portions. At the same time, it is characterized by including a step of flowing the molten glass from the outer peripheral edge thereof. According to such a configuration, it is possible to enjoy the same effects as the corresponding configuration described above.

According to the present invention as described above, it is possible to reduce the thickness variation of the molten glass on the molded product as much as possible and to produce high quality tube glass.

It is a front view which shows the tube glass manufacturing apparatus which concerns on 1st Embodiment. (A) is a vertical sectional view of the molding furnace, and (B) is a horizontal sectional view of the molding furnace. It is a vertical cross-sectional view of a molded body. It is a vertical sectional view which shows the deformation example of a molded body. It is a vertical sectional view of the molded body of the tube glass manufacturing apparatus which concerns on 2nd Embodiment. It is a figure which shows the time variation of the flow rate of the molten glass in an Example. It is a front view which shows the molded body used in an Example, (A) is a molded body of Example 1, (B) is a molded body of Example 2, (C) is a molded body of Example 3, (D ) Is the molded product of Example 4, and (E) is the molded product of Example 5. It is a figure which shows the measurement result of the time variation of the thickness of the molten glass in an Example, (A) is the result of Example 1, (B) is the result of Example 2, (C) is the result of Example 3. (D) is the result of Example 4, and (E) is the result of Example 5.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(First Embodiment)
As shown in FIG. 1, the tube glass manufacturing apparatus 1 according to the first embodiment manufactures tube glass used for, for example, a fluorescent lamp, and includes a melting tank 2, a supply tube 3, and a molding furnace. It is equipped with 4.

The melting tank 2 produces and stores molten glass Gm.

The supply pipe 3 is a supply unit that supplies molten glass Gm from the melting tank 2 into the molding furnace 4. In this embodiment, the supply pipe 3 is made of a conductive metal such as platinum.

The molding furnace 4 has a molded body 5 inside which the molten glass Gm is supplied from the supply pipe 3 and rotates around the axis J in the vertical direction.

The molded body 5 is a molding means for continuously molding the tube glass, and the molded body 5 continuously forms the tube glass by flowing molten glass Gm along the outer surface thereof. The molded body 5 is rotationally driven by a driving device (not shown). The molten glass Gm flowing down from the rotating molded body 5 is pulled downward by a tube pulling device (not shown) at a position below the molded body 5.

The tube glass manufacturing apparatus 1 includes a first heating means 6 for heating the supply tube 3. The first heating means 6 is an electrode connected to the supply pipe 3 and energizes and heats the supply pipe 3. Thereby, the viscosity of the molten glass Gm flowing in the supply pipe 3 is adjusted.

Of course, the first heating means 6 is not limited to this, and may be, for example, a heater arranged around the supply pipe 3.

The temperature of the molten glass Gm supplied from the supply pipe 3 to the molded body 5 is, for example, 1000 ° C. to 1300 ° C., although it depends on the composition of the molten glass Gm.

The viscosity of the molten glass Gm supplied from the supply pipe 3 to the molded body 5 is preferably 100 Pa · s to 2000 Pa · s, and particularly preferably 500 Pa · s to 1000 Pa · s.

The glass composition of the molten glass Gm, for example, in _{mass%, SiO 2 60~80%, B} 2 O 3 0~20%, Al 2 O 3 0~15%, Na 2 O 0~10%, K 2 O _{0~10%, Li 2 O 0~5%} , CaO 0~5%, BaO 0~10%, containing 0 to 5% SrO.

The tube glass manufacturing apparatus 1 includes a second heating means 7 for heating the inside of the molding furnace 4. The second heating means 7 is arranged on the outer peripheral side of the molded body 5, and heats the inside of the molding furnace 4 to heat the molten glass Gm flowing down the molded body 5. Thereby, the viscosity of the molten glass Gm flowing down the molded body 5 is adjusted.

As shown in FIGS. 2A and 2B, in the present embodiment, the second heating means 7 comprises a heat equalizing plate 7a (refractory) and a heater 7b for heating the heat equalizing plate 7a from the outer peripheral side. I have.

The soaking plate 7a constitutes the peripheral wall of the forming furnace 4. A plurality of heat equalizing plates 7a are arranged along the circumferential direction of the molded body 5, and are configured to have the same temperature in the circumferential direction of the molded body 5.

As shown in FIG. 3, the molded body 5 includes a sleeve portion 8 and a metal chip 9 that supports the sleeve portion 8 from below. The sleeve portion 8 is made of, for example, a refractory material, and includes a main body portion 8a and a shaft portion 8b extending upward from the upper end of the main body portion 8a. The sleeve portion 8 has a hole extending along the axis J direction inside the sleeve portion 8, and a metal tube 10 such as platinum is disposed in the hole. The upper end of the metal tube 10 is connected to an air compressor (not shown). A metal chip 9 is connected to the lower end of the metal tube 10. The metal chip 9 is made of a metal such as platinum. A through hole 9a is formed in the metal chip 9 along the axis J direction, and the through hole 9a communicates with the inside of the metal tube 10.

The shaft portion 8b of the sleeve portion 8 and the metal tube 10 in the sleeve portion 8 are subjected to a rotational driving force upward from a drive device (not shown), whereby the sleeve portion 8 and the metal chip 9 are synchronized with each other. Rotate.

The rotation speed of the molded body 5 is, for example, 3 rpm to 15 rpm.

As shown in FIG. 3, the molded body 5 includes a saucer portion 11 at the upper end portion of the main body portion 8a of the sleeve portion 8. In the present embodiment, the saucer portion 11 is the uppermost saucer portion. The saucer portion 11 has a conical shape that is inclined so as to gradually decrease as the inner peripheral edge 11a shifts to the outer peripheral edge 11b. The saucer portion 11 is configured to receive the molten glass Gm supplied from the supply pipe 3 during rotation between the inner peripheral edge 11a and the outer peripheral edge 11b, and to allow the received molten glass Gm to flow down from the outer peripheral edge 11b. ing.

In the present embodiment, the supply pipe 3 drops and supplies the molten glass Gm to one place near the inner peripheral edge 11a of the saucer portion 11.

When the hypotenuse length between the inner peripheral edge 11a and the outer peripheral edge 11b of _{the saucer portion 11 is L 1} (mm) and the inclination angle of the saucer portion 11 with respect to the horizontal plane is α ₁ (°), L ₁ / α ₁ ≧ 2 Relationship is established. L ₁ / α ₁ is preferably 5 or more, and more preferably 6 or more. α ₁ is preferably 15 ° or less, and more preferably 10 ° or less. Here, the _{larger the value of α 1,} the faster the flow velocity of the molten glass Gm toward the outer peripheral edge 11b side of the saucer portion 11, and the _{larger the value of L 1} , the longer the distance to the outer peripheral edge 11b. The area of the saucer portion 11 is increased. Therefore, if the above relational expression is satisfied, the area of the saucer portion 11 becomes appropriately larger than the flow velocity of the molten glass Gm toward the outer peripheral edge 11b of the saucer portion 11, and the residence time of the molten glass Gm in the saucer portion 11 It will be long enough. Therefore, even if the supply amount of the molten glass Gm per unit time fluctuates, the thickness of the molten glass Gm is leveled in the process of moving on the saucer portion 11 over a sufficient time. In other words, it is possible to suppress a situation in which the molten glass Gm flows down from the outer peripheral edge 11b with the thickness fluctuating.

In consideration of space saving and the like, L ₁ / α ₁ is preferably 15 or less, and more preferably 10 or less. Further, although α ₁ > 0, _{if α 1} is too small, the flow speed of the molten glass Gm becomes too slow, and the molten glass Gm may be devitrified on the saucer portion 11. Therefore, α ₁ is preferably 2 ° or more, and more preferably 5 ° or more.

The molded body 5 has a tubular side surface portion 12 composed of a main body portion 8a of the sleeve portion 8 and an outer peripheral surface of the metal chip 9. The molten glass Gm that has flowed down from the outer peripheral edge 11b during rotation flows down to the side surface portion 12. In the present embodiment, the side surface portion 12 is attached to the first uniform diameter portion 12a connected to the outer peripheral edge 11b, the first throttle portion 12b connected to the lower end of the first uniform diameter portion 12a, and the lower end of the first throttle portion 12b. A second uniform diameter portion 12c to be connected and a second throttle portion 12d to be connected to the lower end of the second uniform diameter portion 12c are provided. The first and second uniform diameter portions 12a and 12c are cylindrical portions having a uniform diameter in the axial direction. The diameter of the second uniform diameter portion 12c is smaller than that of the first uniform diameter portion 12a. The first and second drawing portions 12b and 12d are inverted cone-shaped portions whose diameters are gradually reduced downward. In the present embodiment, the second drawing portion 12d is the lowermost drawing portion including the outer peripheral surface of the metal chip 9. The inclination angle of the lowermost throttle portion with respect to the vertical surface, that is, the inclination angle β ₂ of the second throttle portion 12d with respect to the vertical surface is preferably 20 ° or less, and more preferably 15 ° or less. _{On the other hand, the inclination angle β 1} of the first drawing portion 12b with respect to the vertical plane may be larger than, for example, the inclination angle β ₂ , preferably 22 ° or less, more preferably 20 ° or less, and 17 °. It is more preferably less than or equal to, and even more preferably 15 ° or less.

Of course, the shape of the molded body 5 is not limited to the shape described in FIG. 3 as long as _{the saucer portion 11 satisfies the relationship of L 1} / α _{1 ≧ 2.} For example, in the shape described with reference to FIG. 3, the second uniform diameter portion 12c and the second throttle portion 12d of the side surface portion 12 may be omitted. That is, as shown in FIG. 4A, the side surface portion 12 may be configured to include one uniform diameter portion and one throttle portion. Further, for example, in the molded body 5, as shown in FIG. 4B, the side surface portion 12 may not have a drawing portion and the side surface portion 12 may be composed of only a uniform diameter portion, and FIG. 4C ), It is not necessary to have the side surface portion 12. Here, the molded body 5 illustrated in FIGS. 4 (A) to 4 (C) also satisfies the relationship of _{L 1} / α _{1 ≧ 2.} Further, in the molded product 5 illustrated in FIG. 4A, the inclination angle β ₁ corresponding to the lowermost throttle portion is preferably 15 ° or less.

Next, a method of manufacturing the tube glass by the tube glass manufacturing apparatus 1 will be described with reference to FIGS. 1 and 3.

In advance, molten glass Gm is generated from the glass raw material in the melting tank 2 and stored. Further, the first heating means 6 heats the supply pipe 3 to a predetermined temperature, and the second heating means 7 heats the inside of the molding furnace 4 to a predetermined temperature. Then, the air compressor is started to supply air into the metal pipe 10. The air supplied into the metal pipe 10 is ejected downward from the lower end of the metal chip 9 via the through hole 9a.

Next, the molded body 5 is rotated around the vertical axis J by a drive device (not shown). Then, the molten glass Gm is supplied from the melting tank 2 to the supply pipe 3, and the molten glass Gm is supplied from the supply port of the supply pipe 3 to the saucer portion 11 of the molded body 5. Then, the molten glass Gm is received by the saucer portion 11 of the molded body 5 and flows down from the outer peripheral edge 11b of the saucer portion 11. Specifically, the molten glass Gm supplied from the supply pipe 3 forms a single strip-shaped (linear) glass in a molten state. The strip-shaped glass is wound up on the saucer portion 11 by the rotation of the molded body 5. In this process, the strip-shaped glasses radiate over the entire saucer portion 11 while overlapping each other, and flow down from the outer peripheral edge 11b. After that, the molten glass Gm flowing down from the outer peripheral edge 11b flows down the side surface portion 12 of the molded body 5.

The molten glass Gm flowing down from the lower end of the side surface portion 12 of the molded body 5 becomes tubular and becomes a tube glass in a molten state. At this time, the molten glass Gm becomes stable and tubular due to the air ejected from the lower end of the metal chip 9 of the molded body 5. This molten tube glass is gradually solidified and pulled downward by a tube pulling device (not shown) on the downstream side thereof. At this time, the tube pulling device may pull the tube glass while rotating it around the axis J. As a result, tube glass is manufactured. The manufactured tube glass is cut to a predetermined length. This cutting method is not particularly limited, but for example, a notch may be formed with a cutter or the like and split cutting may be performed.

The manufactured tube glass is a high-quality tube glass having good accuracy in outer diameter and thickness, for example, having a diameter of 1 mm to 150 mm and a glass thickness of 0.2 mm to 3.0 mm.

(Second Embodiment)
Next, the tube glass manufacturing apparatus according to the second embodiment will be described. In the second embodiment, the same configurations as those in the first embodiment are designated by the same reference numerals, and detailed description thereof may be omitted.

Regarding the tube glass manufacturing apparatus according to the second embodiment, unlike the first embodiment, as shown in FIGS. 5A and 5B, the molded bodies have a plurality of saucers spaced apart from each other in the vertical direction. It has a part. In FIG. 5A, the molded body has two saucers, and in FIG. 5B, the molded body has three saucers.

More specifically, in FIG. 5A, the molded body 21 is provided between the first saucer portion 22, the second saucer portion 23, and the first saucer portion 22 and the second saucer portion 23. It includes one side surface portion 24 and a second side surface portion 25 provided below the second saucer portion 23.

The first saucer portion 22 has a conical shape and receives the molten glass Gm supplied from the supply pipe 3 during rotation between the inner peripheral edge 22a and the outer peripheral edge 22b, and receives the received molten glass Gm from the outer peripheral edge 22b. It is configured to flow down. The supply pipe 3 directly supplies the molten glass Gm only to the first saucer portion 22 located at the uppermost stage.

The second saucer portion 23 has a conical shape and receives the molten glass Gm flowing down the molded body 21 during rotation between the inner peripheral edge 23a and the outer peripheral edge 23b, and receives the received molten glass Gm on the outer peripheral edge. It is configured to flow down again from 23b.

The first side surface portion 24 includes a first uniform diameter portion 24a connected to the outer peripheral edge 22b of the first tray portion 22, and a first throttle portion 24b connected to the lower end of the first uniform diameter portion 24a. A second saucer portion 23 is connected to the lower end of the first throttle portion 24b.

The second side surface portion 25 includes a second uniform diameter portion 25a connected to the outer peripheral edge 23b of the second saucer portion 23, and a second throttle portion 25b connected to the lower end of the second uniform diameter portion 25a. The second drawing portion 25b includes an outer peripheral surface of the metal chip 9. The first uniform diameter portion 24a and the second uniform diameter portion 25a may have different diameters, but in the present embodiment, they have the same diameter.

Further, as shown in FIG. 5B, the molded body 21 includes a first saucer portion 26, a second saucer portion 27, a third saucer portion 28, a first saucer portion 26, and a second saucer portion 27. The first side surface portion 29 provided between the two, the second side surface portion 30 provided between the second saucer portion 27 and the third saucer portion 28, and the third saucer portion 28 provided below the third saucer portion 28. It is provided with three side surface portions 31.

The first saucer portion 26 has a conical shape and receives the molten glass Gm supplied from the supply pipe 3 during rotation between the inner peripheral edge 26a and the outer peripheral edge 26b, and receives the received molten glass Gm from the outer peripheral edge 26b. It is configured to flow down. The supply pipe 3 directly supplies the molten glass Gm only to the first saucer portion 26 located at the uppermost stage.

The second saucer portion 27 has a conical shape and receives the molten glass Gm that flows down the molded body 21 during rotation between the inner peripheral edge 27a and the outer peripheral edge 27b, and receives the received molten glass Gm on the outer peripheral edge. It is configured to flow down again from 27b. The third saucer portion 28 has the same configuration as the second saucer portion 27.

The first side surface portion 29 includes a first uniform diameter portion 29a connected to the outer peripheral edge 26b of the first saucer portion 26. A second saucer portion 27 is connected to the lower end of the first uniform diameter portion 29a.

The second side surface portion 30 includes a second uniform diameter portion 30a connected to the outer peripheral edge 27b of the second saucer portion 27. A third saucer portion 28 is connected to the lower end of the second uniform diameter portion 30a.

The third side surface portion 31 includes a third uniform diameter portion 31a connected to the outer peripheral edge 28b of the third saucer portion 28, and a throttle portion 31b connected to the lower end of the third uniform diameter portion 31a. Here, the second uniform diameter portion 30a has a larger diameter than the first uniform diameter portion 29a, and the third uniform diameter portion 31a has a larger diameter than the second uniform diameter portion 30a.

As shown in FIGS. 5A and 5B, when a plurality of saucer portions are provided, each saucer portion satisfies the following relational expression. That is, the lengths of the hypotenuses between the inner and outer peripheral edges of the respective saucer portions are set to L ₁ (mm), L ₂ (mm), in order from the uppermost tray portion to the nth stage (lowermost stage) saucer portion. …, L _n (mm), where the tilt angles with respect to the horizontal plane are α ₁ (°), α ₂ (°),…, α _n (°), L ₁ / α ₁ + L ₂ / α ₂ +… + L _The relationship of n / α _n ≧ 2 (preferably 5) is satisfied. Specifically, when n = 2 as shown in FIG. 5 (A), the first saucer portion 22 is the first-stage (top) saucer, and the second saucer 23 is the second-stage (bottom) saucer. It becomes a part and satisfies the relationship of _{L 1} / α ₁ + L ₂ / α _{2 ≧ 2.} On the other hand, when n = 3 as shown in FIG. 5B, the first saucer portion 26 is the first-stage (top) saucer portion, the second saucer portion 27 is the second-stage saucer portion, and the third saucer portion 28. Is the saucer portion of the third stage (bottom stage), and satisfies the relationship of _{L 1} / α ₁ + L ₂ / α ₂ + L ₃ / α _{3 ≧ 2.}

Here, in the first pans 22 and 26 on the uppermost stage, since the temperature of the molten glass Gm is high and the viscosity is low, the effect of leveling the thickness of the molten glass Gm is the highest. Therefore, it is preferable that the first saucer portions 22 and 26 _{satisfy the relationship of L 1} / α ₁ ≧ 2 in order to reduce the thickness variation of the molten glass Gm.

Further, the inclination angle of the lowermost aperture portion with respect to the vertical surface, that is, the inclination angle β ₂ of the second aperture portion 25b of FIG. 5 (A) with respect to the vertical surface and the inclination of the aperture portion 31b of FIG. 5 (B) with respect to the vertical surface. The angles β ₁ are preferably 15 ° or less, respectively. _{On the other hand, the inclination angle β 1} of the first throttle portion 24b in FIG. 5A with respect to the vertical plane is not particularly limited, and may be larger or smaller than, for example, the inclination angle β _{2. The inclination angle β 1 in} FIG. 5 (A) is preferably 20 ° or less, and more preferably 15 ° or less.

By simulating the flow of molten glass flowing down along the molded body by a model experiment, it is possible to suppress the fluctuation of the thickness of the molten glass caused by the fluctuation of the supply flow rate of the molten glass to the saucer of the molded body by the shape of the molded body. confirmed. The fluctuation in the thickness of the molten glass was confirmed by measuring the thickness of the molten glass at the lower part of the side surface of the molded body with a laser displacement sensor.

Table 1 shows the conditions of the molded body shape of each example used in the experiment. Table 2 shows the experimental conditions common to each example. The density, viscosity, and flow rate of the molten glass in Table 2 are values at the supply port at the tip of the supply pipe. Further, the time variation of the flow rate of the molten glass at the supply port of the supply pipe is as shown in FIG.

8 (A) to 8 (E) show the measurement results of the time variation of the thickness of the molten glass at the lower part of the side surface of the molded product of each example. As shown in the figure, in each example, since L ₁ / α ₁ is 2 or more, the thickness fluctuation of the molten glass is suppressed to about ± 0.3 mm. In particular, as shown in FIG. 8 (E), in _{Example 5 in which L 1} / α ₁ is 6 or more, the thickness variation of the molten glass is suppressed to a very small value of about ± 0.1 mm. Here, in Examples 1, 2 and 4, the shape of the saucer portion was the same and the shape of the side surface portion was different, but no significant difference was observed in the thickness variation of the molten glass. On the other hand, in Example 5 in which the shape of the saucer portion was significantly changed, the result was obtained that the thickness variation of the molten glass was the smallest. Therefore, the shape of the saucer portion of the molded product is important for reducing the thickness variation of the molten glass, and _{it is preferable that L 1} / α ₁ is 2 or more, and L ₁ / α ₁ is 5 or more. It can be recognized that it is more preferable.

Although the experimental results are omitted, when L ₁ / α ₁ is less than 2, the thickness variation of the molten glass tends to be larger than ± 0.3 mm.

Further, in the above embodiment, the case where only one saucer portion is provided is illustrated, but the same applies to the case where a plurality of saucer portions are provided at intervals in the vertical direction. That is, what was absorbed by the thickness variation of the molten glass in one saucer portion is divided and absorbed by the plurality of saucer portions. Therefore, in order to obtain the same effect as that of one saucer illustrated in the above embodiment for the entire plurality of saucer portions, the _{relationship of L 1} / α ₁ + L ₂ / α ₂ + ... + L _n / α _n ≧ 2 is established. It can be recognized that it should be satisfied.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of its technical idea.

For example, as shown in FIGS. 5A and 5B, when a plurality of saucer portions are provided at intervals in the vertical direction, supply portions such as supply pipes are provided at positions corresponding to the respective saucer portions. The molten glass may be supplied to each saucer portion.

1 Tube glass manufacturing equipment 2 Melting tank 3 Supply tube 4 Molding furnace 5 Molded body 8 Sleeve part 9 Metal chip 10 Metal tube 11 Recipient part 21 Molded body 22, 23, 26, 27, 28 Recipient part Gm Molten glass

Claims (6)

The tube glass is provided with a supply unit for supplying the molten glass and a molded body that rotates around the vertical axis while the molten glass is supplied from the supply unit, and the molten glass is allowed to flow down from the rotating molded body. It is a tube glass manufacturing equipment to be manufactured.
The molded body is provided with one or a plurality of saucer portions that receive the molten glass between the inner peripheral edge and the outer peripheral edge at intervals in the vertical direction.
Each of the one or a plurality of the saucer portions has a conical shape that is gradually lowered as it moves from the inner peripheral edge to the outer peripheral edge, and is configured to flow down the molten glass from the outer peripheral edge. Cone,
The hypotenuse lengths between the inner peripheral edge and the outer peripheral edge of each of the saucer portions are L ₁ (mm), L ₂ (mm), ..., L _n (mm), respectively, in order from the uppermost saucer portion. When the inclination angles of the saucer with respect to the horizontal plane are α ₁ (°), α ₂ (°), ..., α _n (°).
L ₁ / α ₁ + L ₂ / α ₂ + ... + L _n / α _n ≧ 2 (n is an integer of 1 or more)
A tube glass manufacturing apparatus characterized by satisfying the above relationships. The tube glass manufacturing apparatus according to claim 1, wherein the saucer portion on the uppermost stage _{satisfies the relationship of L 1} / α _{1 ≧ 2.} The tube glass manufacturing apparatus according to claim 1 or 2, _{wherein the inclination angle α 1 of the} saucer portion on the uppermost stage is 15 ° or less. The molded body includes a tubular side surface portion that guides the molten glass flowing down from the outer peripheral edge at a position below the outer peripheral edge.
The tube glass according to any one of claims 1 to 3, wherein the side surface portion includes one or a plurality of throttle portions that gradually reduce in diameter in the vertical direction at intervals in the vertical direction. Manufacturing equipment. The tube glass manufacturing apparatus according to claim 4, wherein the inclination angle of the lowermost throttle portion with respect to the vertical surface is 15 ° or less. A tube glass manufacturing method for manufacturing tube glass by supplying molten glass from a supply unit to a molded body rotating around an axis in the vertical direction and allowing molten glass to flow down from the molded body.
The molded body includes one or a plurality of saucer portions that receive the molten glass at intervals in the vertical direction.
Each of the one or more saucers has a conical shape that is inclined so as to gradually decrease as it moves from the inner peripheral edge to the outer peripheral edge.
The length of the hypotenuse between the inner peripheral edge and the outer peripheral edge of each of the saucer portions is L ₁ (mm), L ₂ (mm), ..., L _n (mm), and the horizontal plane in order from the uppermost tray portion. When the tilt angle with respect to is α ₁ (°), α ₂ (°), ..., α _n (°),
L ₁ / α ₁ + L ₂ / α ₂ + ... + L _n / α _n ≧ 2 (n is an integer of 1 or more)
Satisfy the relationship
A method for producing tube glass, which comprises a step of receiving the molten glass between the inner peripheral edge and the outer peripheral edge of each of the saucer portions and allowing the molten glass to flow down from the outer peripheral edge thereof. ..