WO2023277076A1

WO2023277076A1 - Optical fiber production device and optical fiber production method

Info

Publication number: WO2023277076A1
Application number: PCT/JP2022/025999
Authority: WO
Inventors: 正榎本
Original assignee: 住友電気工業株式会社
Priority date: 2021-07-02
Filing date: 2022-06-29
Publication date: 2023-01-05
Also published as: JPWO2023277076A1; CN117412933A

Abstract

An optical fiber production device comprising: a drawing tower; a drawing furnace that is mounted on the drawing tower and that heats and melts an optical fiber base material to spin an optical fiber; and an application mechanism that is mounted on the drawing tower and that applies, to the drawing tower, a second moment having a direction opposite to the acting direction of a first moment applied to the drawing tower by the optical fiber base material, wherein the application mechanism is capable of reducing the second moment as the optical fiber base material becomes smaller.

Description

Optical fiber manufacturing device and optical fiber manufacturing method

TECHNICAL FIELD The present disclosure relates to an optical fiber manufacturing apparatus and an optical fiber manufacturing method.
This application claims priority based on Japanese application No. 2021-110795 filed on July 2, 2021, and incorporates all the descriptions described in the Japanese application.

In Patent Document 1, an optical fiber preform and a dummy preform for the optical fiber preform are attached to a drawing tower, and the vibration of the optical fiber preform is activated by controlling a damping device based on the vibration of the dummy preform. A damped optical fiber drawing apparatus is disclosed.

Japanese Patent Application Laid-Open No. 2004-161499

An optical fiber manufacturing apparatus according to one aspect for achieving the above object,
a drawing tower,
a drawing furnace mounted on the drawing tower for heating and melting an optical fiber preform to spin an optical fiber;
an imparting mechanism mounted on the drawing tower for imparting a second moment to the drawing tower in a direction opposite to the acting direction of the first moment imparted to the drawing tower by the optical fiber preform. ,
The imparting mechanism can reduce the second moment as the optical fiber preform becomes smaller.

In addition, an optical fiber manufacturing method according to one aspect for achieving the above object,
heating and melting an optical fiber preform in a drawing furnace mounted on a drawing tower to spin the optical fiber;
A second moment in a direction opposite to the direction of action of the first moment applied to the drawing tower by the optical fiber preform is applied to the drawing tower while decreasing as the optical fiber preform becomes smaller. and a step.

FIG. 1 is a schematic configuration diagram of an optical fiber manufacturing apparatus according to the first embodiment, showing a state immediately after a drawing process is started. FIG. 2 is a schematic configuration diagram of the optical fiber manufacturing apparatus according to the first embodiment, showing a state after a while since the drawing process was started. FIG. 3 is a graph showing the relationship between the weight of the optical fiber preform and the magnitude of the first moment. FIG. 4 is a schematic configuration diagram of an optical fiber manufacturing apparatus according to the second embodiment.

[Problems to be Solved by the Present Disclosure]
By the way, the drawing tower may bend due to the weight of the base material, for example. If the draw tower is flexed, there is a risk that the actual running position of the glass fiber will deviate from the intended running position. Therefore, in the manufacture of optical fibers, it is important to suppress the deflection of the drawing tower so that the actual running position and the planned running position do not deviate.

An object of the present disclosure is to provide an optical fiber manufacturing apparatus and an optical fiber manufacturing method capable of suppressing bending of a drawing tower.

[Effect of the present disclosure]
ADVANTAGE OF THE INVENTION According to this indication, the optical fiber manufacturing apparatus and optical fiber manufacturing method which can suppress the bending of a drawing tower can be provided.

(Description of Embodiments of the Present Disclosure)
First, the embodiments of the present disclosure are listed and described.
An optical fiber manufacturing apparatus according to an aspect of the present disclosure includes
(1) a drawing tower;
a drawing furnace mounted on the drawing tower for heating and melting an optical fiber preform to spin an optical fiber;
an imparting mechanism mounted on the drawing tower for imparting a second moment to the drawing tower in a direction opposite to the acting direction of the first moment imparted to the drawing tower by the optical fiber preform. ,
The imparting mechanism can reduce the second moment as the optical fiber preform becomes smaller.
According to this configuration, the applying mechanism applies the second moment to the drawing tower in a direction opposite to the acting direction of the first moment applied to the drawing tower by the optical fiber preform. Since the imparting mechanism can reduce the second moment as the optical fiber preform becomes smaller, the optical fiber manufacturing apparatus according to the above configuration can suppress the bending of the drawing tower.

Further, in the optical fiber manufacturing apparatus according to one aspect of the present disclosure,
(2) the applying mechanism includes a moving mechanism capable of moving in a predetermined direction and a weight body supported by the moving mechanism;
The center of gravity of the weight moves toward or away from the center of the drawing tower as the movement mechanism moves.
According to this configuration, the center of gravity of the weight provided in the applying mechanism moves toward or away from the center of the drawing tower as the movement mechanism moves. Therefore, for example, by moving the moving mechanism in accordance with the change in the first moment over time, the movement of the moving mechanism can change the second moment over time.

Further, in the optical fiber manufacturing apparatus according to one aspect of the present disclosure,
(3) the drawing tower has a grounding part that is grounded on the surface on which the drawing tower is arranged;
The center of gravity of the weight body is located outside the outer periphery of the ground contact portion when viewed from above.
According to this configuration, the second moment can be effectively applied to the drawing tower.

Further, in the optical fiber manufacturing apparatus according to one aspect of the present disclosure,
(4) The height of the position where the applying mechanism applies the second moment to the drawing tower is 0.8 times or more the height of the position of the drawing furnace.
If the height of the position where the applying mechanism applies the second moment to the drawing tower is less than 0.8 times the height of the position of the drawing furnace, the second moment is effectively applied to the drawing tower. cannot effectively cancel out the first moment from the second moment. Therefore, the height of the position where the applying mechanism applies the second moment to the drawing tower is preferably 0.8 times or more the height of the position of the drawing furnace.

Further, in the optical fiber manufacturing apparatus according to one aspect of the present disclosure,
(5) The height of the drawing furnace is 12 m or more.
The higher the position of the drawing furnace, the greater the first moment, so the effect of applying the second moment to the drawing tower becomes higher, especially when the height of the drawing furnace is 12 m or more. In some cases, this disclosure is preferred.

Further, an optical fiber manufacturing method according to an aspect of the present disclosure includes:
(6) heating and melting the optical fiber preform in a drawing furnace mounted on a drawing tower to spin the optical fiber;
A second moment in a direction opposite to the direction of action of the first moment applied to the drawing tower by the optical fiber preform is applied to the drawing tower while decreasing as the optical fiber preform becomes smaller. and a step.
According to this configuration, the second moment in the direction opposite to the direction of action of the first moment applied to the drawing tower by the optical fiber base material is applied to the drawing tower while decreasing as the base material becomes smaller. Therefore, bending of the drawing tower can be suppressed.

Further, an optical fiber manufacturing method according to an aspect of the present disclosure includes:
(7) reducing the second moment by moving the center of gravity of the weight toward or away from the center of the draw tower;
According to this configuration, the center of gravity of the weight moves toward or away from the center of the drawing tower, so the second moment can be changed over time.

Further, an optical fiber manufacturing method according to an aspect of the present disclosure includes:
(8) Move the center of gravity of the weight body outside the outer circumference of the grounding portion of the drawing tower when viewed from above.
According to this configuration, the second moment can be effectively applied to the drawing tower.

Further, an optical fiber manufacturing method according to an aspect of the present disclosure includes:
(9) Applying the second moment to the drawing tower at a height that is 0.8 times or more the height of the drawing furnace.
Effectively imparting the second moment to the drawing tower if the height location where the second moment is imparted to the drawing tower is less than 0.8 times the height of the location of the drawing furnace cannot effectively cancel out the first moment from the second moment. Therefore, it is preferable to apply the second moment to the drawing tower at a height that is at least 0.8 times the height of the drawing furnace.

Further, an optical fiber manufacturing method according to an aspect of the present disclosure includes:
(10) Spinning the optical fiber for 1000 km or more per one preform while reducing the second moment.
The longer the fiber length of the spun optical fiber, the larger the optical fiber preform and the larger the first moment. Therefore, the longer the fiber length of the optical fiber to be spun, the higher the need to apply the second moment to the drawing tower, and the present disclosure is particularly suitable when spinning an optical fiber with a fiber length of 1000 km or more. be.

(Details of embodiments of the present disclosure)
A specific example of an optical fiber manufacturing apparatus according to an embodiment of the present disclosure will be described below with reference to the drawings. The present disclosure is not limited to these examples, but is indicated by the scope of the claims, and is intended to include all modifications within the meaning and scope of equivalents of the scope of the claims.

(First embodiment)
An optical fiber manufacturing apparatus 1 according to this embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram illustrating an optical fiber manufacturing apparatus 1. As shown in FIG. FIG. 1 illustrates the state immediately after the wire drawing process is started.

As illustrated in FIG. 1, an optical fiber manufacturing apparatus 1 includes a drawing tower 2, a chuck 3, a control unit 4, a drawing furnace 5, an outer diameter measuring device 8, a forced cooling device 9, a coating It comprises a device 10 , a direct roller 11 , a winding device 12 , a applying mechanism 13 and a capstan device 14 . In this embodiment, for convenience of explanation, the horizontal direction in FIG. ) are referred to as Z-axis directions, respectively, and the center position of the drawing tower 2 is defined as the zero point of each axis.

The optical fiber manufacturing apparatus 1 has a chuck 3 for gripping the support rod 6a of the optical fiber preform 6 on the upper part of the drawing tower 2. The chuck 3 is cantilevered on the drawing tower 2 by a chuck support 3a.

The drawing tower 2 can be placed, for example, inside the building. The drawing tower 2 includes a grounding portion 21 that is grounded on the floor surface F of the building (an example of the surface on which the drawing tower 2 is arranged). It is preferable that the drawing tower 2 is independently built on the foundation without being connected to surrounding buildings.

The chuck 3 is movable in the horizontal direction (X-axis direction, Y-axis direction). Thereby, the chuck 3 can horizontally adjust the position (gripping position) at which the support rod 6a of the optical fiber preform 6 is gripped. Moreover, the chuck supporting portion 3a is slidable in the vertical direction (Z-axis direction) by a slide portion 3b provided on the upper portion of the drawing tower 2 along the vertical direction. As a result, after the support rod 6a is gripped by the chuck 3, the chuck support portion 3a can be slid downward to accommodate the optical fiber preform 6 inside the drawing furnace 5. FIG.

The control unit 4 controls the optical fiber manufacturing apparatus 1. For example, the control unit 4 controls the movement of the chuck 3 in the horizontal direction to horizontally adjust the position (gripping position) at which the support rod 6a of the optical fiber preform 6 is gripped. Also, the control unit 4 measures or calculates the weight of the optical fiber preform 6 . This weight may be measured with a weight scale or calculated from the diameter and length of the optical fiber preform 6 . For example, an operator inputs the numerical values of the diameter and length of the optical fiber preform 6 to be drawn on a touch panel or the like (not shown), or the diameter and length of the optical fiber preform 6 are input by a sensor (not shown). By sensing the length, the controller 4 can calculate the weight of the optical fiber preform 6 . The control unit 4 calculates the moment applied to the drawing tower 2 and the bending amount of the drawing tower 2 based on the calculated weight of the optical fiber preform 6 .

The drawing furnace 5 is supported on the upper part of the drawing tower 2 . The height H of the position of the drawing furnace 5 (that is, the height H from the floor surface F to the center of the drawing furnace 5 (the middle position between the upper end and the lower end of the drawing furnace 5)) is 12 m. That's it. The drawing furnace 5 is equipped with a heater, and the heater heats the optical fiber preform 6 accommodated therein. An optical fiber preform 6 heated and melted in a drawing furnace 5 is drawn into an optical fiber 7 with its tip exposed.

The optical fiber preform 6 is made of, for example, silica-based glass. The optical fiber preform 6 has a predetermined weight.

The outer diameter measuring instrument 8 is, for example, a laser beam type measuring instrument provided below the drawing furnace 5 . The outer diameter measuring device 8 measures the outer diameter of the optical fiber 7 . The outer diameter measuring device 8 controls driving of, for example, the capstan device 14 so that the outer diameter value of the optical fiber 7 measured by the outer diameter measuring device 8 falls within a predetermined range during wire drawing. A signal is generated and the control signal is sent to the capstan device 14 .

The forced cooling device 9 has an insertion hole through which the hot optical fiber 7 drawn in the drawing furnace 5 is passed. The forced cooling device 9 forcibly cools the optical fiber 7 inserted through the insertion hole by sending cooling gas into the forced cooling device 9 .

The coating device 10 coats the optical fiber 7 cooled by the forced cooling device 9 with resin. If the resin is an ultraviolet curing resin, an ultraviolet irradiation device may be provided below the coating device 10 to irradiate the optical fiber 7 with ultraviolet rays to cure the resin. After the resin hardens, the optical fiber 7 passes through the roller 11 and the capstan device 14 and is taken up by the take-up device 12 with a constant tension. The capstan device 14 is controlled based on a control signal from the outer diameter measuring device 8, whereby an optical fiber 7 having a predetermined glass outer diameter is obtained.

By the way, since the chuck 3 is supported by the drawing tower 2 in a cantilevered state, when the optical fiber preform 6 is supported by the chuck 3, the drawing tower 2 is subjected to a first moment M1. At this time, the control unit 4 uses the weight G1 of the optical fiber preform 6 and the distance D1 from the center of the optical fiber preform 6 to the center line CR of the drawing tower 2, based on the following formula (1): Calculate the first moment M1 (A is a constant). M1=G1*D1+A Expression (1)

When the first moment M1 is applied to the drawing tower 2, the drawing tower 2 bends. When the drawing tower 2 bends, the chuck 3 and the optical fiber preform 6 tilt toward the lower left in FIG. If the chuck 3 and the optical fiber preform 6 are tilted, the position through which the drawn optical fiber 7 passes deviates from the position of the aligned pass line, and as a result, the optical fiber 7 contacts the forced cooling device 9 or the like. However, disconnection may occur.

Therefore, the inventor studied a method for solving the above problem, and as a result, suppressed the bending of the drawing tower 2 by applying a second moment M2 to the drawing tower 2 to offset the first moment M1. I came to think that it might be possible. Therefore, the optical fiber manufacturing apparatus 1 according to this embodiment includes the imparting mechanism 13 capable of imparting the second moment M2 to the drawing tower 2 .

The imparting mechanism 13 is located opposite the optical fiber preform 6 with respect to the center line CR of the drawing tower 2 on the X axis. The applying mechanism 13 applies a second moment M2 to the drawing tower 2 in a direction opposite to the acting direction of the first moment M1 applied to the drawing tower 2 by the optical fiber preform 6 . The applying mechanism 13 includes a plate-like portion 131 , a moving mechanism 132 and a weight body 133 .

The plate-like portion 131 is, for example, a substantially rectangular flat plate member extending in the horizontal direction (X-axis direction, Y-axis direction). The height h at the position of the plate-like portion 131 (that is, the height h from the floor surface F to the lower end of the plate-like portion 131) is 0.8 times or more the height H at the position of the drawing furnace 5. is preferable.

The moving mechanism 132 moves on the plate-shaped part 131 in a predetermined direction, for example, in a direction approaching or away from the center of the drawing tower 2 . The center of the drawing tower 2 is, for example, the center position P (the position of the zero point described above) of the three axes (X-axis, Y-axis and Z-axis) in the drawing tower 2 . In this embodiment, the moving mechanism 132 moves in the X-axis direction. The moving mechanism 132 is, for example, electrically connected to the controller 4 and moves based on an instruction signal from the controller 4 . However, the movement of the moving mechanism 132 can also be realized by means other than such electrical control. For example, the moving mechanism 132 may be moved to a desired position by mechanical control, or may be manually moved to a desired position by an operator. Further, the moving mechanism 132 may always move, or may move intermittently at predetermined time intervals.

The weight body 133 is, for example, a weight having a predetermined weight. The weight of the weight body 133 can be arbitrarily set by the operator. The weight body 133 is supported by the moving mechanism 132 . Therefore, when the moving mechanism 132 moves, the weight body 133 moves along with the movement of the moving mechanism 132 . Therefore, the center of gravity 133a of the weight body 133 moves in either direction of the X-axis (horizontal direction in FIG. 1) as the moving mechanism 132 moves. That is, the center of gravity 133a of the weight body 133 moves toward or away from the center (position P) of the drawing tower 2 . Note that the center of gravity 133a of the weight body 133 is located outside the outer circumference of the ground contact portion 21 in top view during wire drawing. In other words, the center of gravity 133a of the weight body 133 is located outside the area V inside the drawing tower 2 in top view during the drawing.

The second moment M2 imparted by the imparting mechanism 13 having such a configuration is controlled by the control unit 4 to obtain a total weight G2 which is the sum of the weight of the moving mechanism 132 and the weight of the weight body 133, and the distance D2 from the center of gravity 133a of the weight to the center line CR of the drawing tower 2 (B is a constant). M2=G2*D2+B Expression (2)

Next, an optical fiber manufacturing method according to an embodiment of the present disclosure will be described with reference to FIGS. 1 and 2. FIG. FIG. 2 exemplifies the state when some time has passed since the wire drawing process was started. The optical fiber manufacturing method of this embodiment uses the optical fiber manufacturing apparatus 1 illustrated in FIGS. be.

(Suspension process)
The chuck supporting portion 3a is slid upward by the sliding portion 3b, and the chuck 3 grips the supporting rod 6a of the optical fiber preform 6 used for drawing. After the support rod 6a is gripped by the chuck 3, the chuck support portion 3a is slid downward, and the optical fiber preform 6 is suspended inside the drawing furnace 5 and accommodated.

(drawing process)
An optical fiber preform 6 housed inside a drawing furnace 5 is heated by a heater. The tip of the optical fiber preform 6 is heated to a predetermined temperature (for example, 2000° C.) to melt the optical fiber preform 6, and the glass block at the tip is pulled down to extract the lead. Subsequently, drawing is performed while reducing the diameter of the glass. As the drawing progresses, the optical fiber 7 is drawn from the tip of the optical fiber preform 6 by gradually sliding the chuck supporting portion 3a downward.

In the optical fiber manufacturing apparatus 1, the positions of the chuck 3 and the direct-lower roller 11, the central axes of the drawing furnace 5, the forced cooling device 9, the coating device 10, etc. are aligned in advance before drawing, and the drawn optical fiber 7 is It is necessary to align the path lines to be passed. This alignment of the pass lines is normally performed in a state in which the optical fiber preform 6 is not suspended.

However, for the reason described above, when the optical fiber preform 6 is suspended, the position through which the drawn optical fiber 7 passes is deviated from the position of the aligned pass line. 9 etc., and disconnection may occur.

Also, as illustrated in FIG. 2, the optical fiber preform 6 becomes smaller as the drawing progresses, so the weight of the optical fiber preform 6 decreases as the drawing progresses. As illustrated in FIG. 3, the weight of the optical fiber preform 6 and the magnitude of the first moment M1 are in a linearly proportional relationship. Therefore, the first moment M1 decreases as the drawing progresses. Therefore, in order to suppress the bending of the drawing tower 2, the inventor applies the second moment M2 according to the first moment M1, and changes the second moment M2 according to the change of the first moment M1. I noticed a good thing.

Therefore, the inventor got the idea of moving the moving mechanism 132 that supports the weight body 133 to reduce the second moment M2 in accordance with the weight reduction of the optical fiber preform 6 .

In the state illustrated in FIG. 1, the control unit 4 calculates the first moment M1, calculates the distance D2 where the first moment M1 and the second moment M2 are equal, and moves the moving mechanism 132 to the position corresponding to the distance D2. move.

As the line drawing progresses, the state shown in Fig. 2 is reached. In the state illustrated in FIG. 2, the control unit 4 calculates the first moment m1. The first moment m1 is calculated based on the following formula (3) from the weight g1 of the optical fiber preform 6 and the distance D1 from the optical fiber preform 6 to the center line CR of the drawing tower 2. be. Note that the weight g1 is smaller than the weight G1. m1=g1*D1+A Expression (3)

The control unit 4 calculates the first moment m1, calculates the distance d2 where the first moment m1 and the second moment m2 are equal, and moves the moving mechanism 132 to the position corresponding to the distance d2. The second moment m2 is calculated from the total weight G2, which is the sum of the weight of the moving mechanism 132 and the weight body 133, and the center of gravity 133a of the combined weight body of the moving mechanism 132 and the weight body 133. and the distance d2 to the center line CR of , based on the equation (4). m2=G2*d2+B Expression (4)

Since the weight g1 is smaller than the weight G1, the first moment m1 is smaller than the first moment M1. Therefore, the second moment m2 should be smaller than the second moment M2, and the distance d2 will be shorter than the distance D2. That is, as the weight of the optical fiber preform 6 decreases, the moving mechanism 132 approaches the center (position P) of the drawing tower 2 .

Thus, the imparting mechanism 13 can reduce the second moment M2 as the weight of the optical fiber preform 6 decreases. The imparting mechanism 13 may continuously reduce the second moment M2, or may intermittently reduce the second moment M2 at predetermined time intervals. This control is continued until the entire effective portion of the optical fiber preform 6 is drawn.

When the drawing progresses further and all the effective portions of the optical fiber preform 6 are drawn, the drawing ends. In the optical fiber manufacturing method according to the present embodiment, a large optical fiber preform 6 is used, and the optical fiber 7 is spun for 1000 km or more per optical fiber preform 6 .

As described above, in the optical fiber manufacturing apparatus 1 and the optical fiber manufacturing method according to the present embodiment, the imparting mechanism 13 applies the second moments M2, m2 in the direction opposite to the acting direction of the first moments M1, m1. , to the draw tower 2 . Further, the imparting mechanism 13 reduces the second moment M2 as the optical fiber preform 6 becomes smaller. Therefore, according to the optical fiber manufacturing apparatus 1 and the optical fiber manufacturing method according to the present embodiment, bending of the drawing tower 2 can be suppressed.

In this embodiment, the center of gravity 133a approaches the center (position P) of the drawing tower 2 as the moving mechanism 132 moves, so the second moment M2 can be decreased over time by moving the moving mechanism 132. can be done.

When the center of gravity 133a is positioned inside the outer circumference of the ground contact portion 21 in top view, the distance from the weight body 133 to the center line CR cannot be secured. cannot be given. However, in this embodiment, the center of gravity 133a of the weight body 133 is positioned outside the outer circumference of the ground contact portion 21 when viewed from above. Therefore, according to the optical fiber manufacturing apparatus 1 and the optical fiber manufacturing method according to the present embodiment, the second moments M2 and m2 can be effectively applied to the drawing tower 2 .

(Second embodiment)
Next, an optical fiber manufacturing apparatus 1A according to this embodiment will be described with reference to FIG. In the description of the optical fiber manufacturing apparatus 1A, the same components as those of the optical fiber manufacturing apparatus 1 according to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

FIG. 4 is a schematic configuration diagram of the optical fiber manufacturing apparatus 1A. The optical fiber manufacturing apparatus 1A includes a chuck 30, a drawing furnace 50, an outer diameter measuring device 80, a forced cooling device 90, a coating device 100, a direct roller 110, a winding device 120, and a capstan device 140. and are further provided, which is different from the optical fiber manufacturing apparatus 1 . Further, the optical fiber manufacturing apparatus 1A is capable of moving the weight member 133 not only to the right side of the drawing tower 2 in FIG. Differs from device 1. Thus, the optical fiber manufacturing apparatus 1A is an optical fiber manufacturing apparatus having two drawing lines for one drawing tower. In this embodiment, the control unit 4 controls the horizontal movement of the chuck 30 to horizontally adjust the position (gripping position) at which the support rod 60a of the optical fiber preform 60 is gripped. The controller 4 also measures or calculates the weight of the optical fiber preform 60 .

The chuck 30 may have the same configuration as the chuck 3. Also, the configuration from the wire drawing furnace 50 to the capstan device 140 may be the same configuration as the configuration from the wire drawing furnace 5 to the capstan device 14 . However, it is assumed that the weight G3 of the optical fiber preform 60 is smaller than the weight G1 of the optical fiber preform 6 in the state shown in FIG.

The chuck 30 includes a chuck support portion 30a having the same configuration as the chuck support portion 3a, and a slide portion 30b having the same configuration as the slide portion 3b. The chuck 30 grips a support rod 60a of an optical fiber preform 60 having the same structure as the optical fiber preform 6. As shown in FIG. Since the optical fiber preform 60 has a predetermined weight, when the optical fiber preform 60 is supported by the chuck 30, the drawing tower 2 exerts a first force in a direction opposite to the acting direction of the first moment M1. Three moments M3 are applied. The third moment M3 is calculated based on the following equation (5) using the weight G3 of the optical fiber preform 60 and the distance D3 from the optical fiber preform 60 to the center line CR of the drawing tower 2. (C is a constant). M3=G3*D3+C Expression (5)

Since the weight G3 of the optical fiber preform 60 is smaller than the weight G1 of the optical fiber preform 6, the third moment M3 is smaller than the first moment M1. Therefore, also in this embodiment, the chuck 3 and the optical fiber preform 6 are tilted in the lower left direction in FIG. 1, and as a result, the drawing tower 2 is bent.

The control unit 4 calculates a distance D4 that satisfies the following formula (6), and moves the moving mechanism 132 of the imparting mechanism 13 to a position corresponding to the distance D4. The distance D4 is the distance from the center of the weight (the center of gravity 133a) of the combination of the moving mechanism 132 and the weight body 133 to the center line CR of the drawing tower 2. FIG. M1-M3=M2=G2*D4+B Expression (6)

When the moving mechanism 132 moves to the position corresponding to the distance D4, the first moment M1 becomes equal to the sum of the second moment M2 and the third moment M3, so the bending amount of the drawing tower 2 can be made substantially zero. can. Thus, even if the present disclosure is applied to the optical fiber manufacturing apparatus 1A having two drawing lines for one drawing tower, the same effect as the first embodiment can be obtained.

Next, an example of this embodiment will be described. Note that the present disclosure is not limited to the following examples.

Under conditions different from each other, the optical fiber 7 is spun using the optical fiber manufacturing apparatus 1 according to the present embodiment, and the positional deviation of the drawing furnace 5 and the positional deviation of the pass line at the start and end of drawing are measured. , disconnection frequency, and .

Tables 1 and 2 show the positional deviation of the drawing furnace 5 and the positional deviation of the pass line at the start and end of drawing under various conditions, and the wire breakage frequency. The positional deviation of the drawing furnace 5 at the start and end of drawing is good when the deviation is 3.0 mm or less, and is unsatisfactory when it exceeds 3.0 mm. Therefore, the good range of the amount of positional deviation of the drawing furnace 5 is 3.0 mm or less. The misalignment of the pass line at the start and end of drawing is good when the amount of misalignment is 0.3 mm or less, and is bad when it exceeds 0.3 mm. Therefore, the good range of the positional deviation amount of the pass line is 0.3 mm or less. The disconnection frequency is good when it is 0.1/1000 km or less, and is bad when it exceeds 0.1/1000 km. Therefore, the good range of disconnection frequency is 0.1 cases/1000 km or less. As for the evaluation, these are comprehensively judged and expressed in three grades of A, B, and C. A indicates good, B indicates relatively good, and C indicates bad. The initial position of the moving mechanism 132 is the distance D2 from the center of gravity 133a to the center line CR of the drawing tower 2, and the final position of the moving mechanism 132 is the distance from the center of gravity 133a to the center line CR of the drawing tower 2. d2. Also, the fiber length is the length of the optical fiber 7 spun from one optical fiber preform 6 .

First, Experimental Examples 1 and 2 will be explained. In Experimental Example 1, the distance D2 at the start of drawing and the distance d2 at the end of drawing are both 750 mm. That is, in Experimental Example 1, the moving mechanism 132 was not moved during the drawing process. On the other hand, in Experimental Example 2, the distance D2 at the start of drawing is 1304 mm, but the distance d2 at the end of drawing is 754 mm. That is, in Experimental Example 2, the moving mechanism 132 is moved so as to approach the center (position P) of the drawing tower 2 during the drawing process. Other parameters in Experimental Example 1 and Experimental Example 2 are the same.

In Experimental Example 1, the misalignment of the drawing furnace 5 at the start of drawing, the misalignment of the pass line at the start of drawing, and the frequency of wire breakage were out of the good range, so the evaluation was made C. . On the other hand, in Experimental Example 2, the misalignment of the wire drawing furnace 5 and the misalignment of the pass line at the start and end of drawing, and the disconnection frequency were all within the favorable range, so evaluation was given as A. According to Experimental Examples 1 and 2, when the moving mechanism 132 is moved closer to the center (position P) of the drawing tower 2 during the drawing process, the displacement of the drawing furnace 5 and the position of the pass line It has been confirmed that the displacement and the disconnection frequency can be reduced.

Next, Experimental Examples 3 to 5 will be explained. In Experimental Examples 3 to 5, the height h of the position of the plate-like portion 131 is different. Further, in Experimental Examples 3 to 5, although the weights of the weight bodies are different, they are approximately the same. The initial position of the moving mechanism 132 and the final position of the moving mechanism 132 are different. Other parameters in Experimental Examples 3 to 5 are the same. In each of Experimental Examples 3 to 5, the moving mechanism 132 is moved so as to approach the center (position P) of the drawing tower 2 during the drawing process. As shown in Table 1, since the height h at the position of the plate-like portion 131 in Experimental Example 3 is 15.0 m, it is 0.8 times the height H at the position of the drawing furnace 5, that is, from 16.8 m. is also low. On the other hand, the height h at the position of the plate-like portion 131 in Experimental Examples 4 and 5 is 18.0 m and 18.5 m, respectively. , i.e. higher than 16.8 m.

In Experimental Example 3, control was performed by changing the position of the moving body as much as possible. As a result, the misalignment of the line and the disconnection frequency of the line deviated from the good range. In particular, the disconnection frequency was evaluated as C because it greatly deviated from the favorable range of the disconnection frequency. In Experimental Example 4, the positional deviation of the drawing furnace 5 at the start and end of drawing and the positional deviation of the pass line at the end of drawing are within a good range, but the positional deviation of the pass line at the start of drawing. was slightly out of the good range, and the disconnection frequency was out of the good range. On the other hand, in Experimental Example 5, the misalignment of the drawing furnace 5 and the misalignment of the pass line at the start and end of drawing, and the disconnection frequency were all within the good range, so evaluation was given as A. Thus, from these examples, when the height h at the position of the plate-like portion 131 is less than 0.8 times the height H at the position of the drawing furnace 5, the second moment M2, m2 is applied to the drawing tower 2 was not effectively given. In other words, it was confirmed that the height h at the position of the plate-like portion 131 is preferably 0.8 times or more the height H at the position of the drawing furnace 5 .

Next, Experimental Examples 6 to 10 will be explained. As shown in Tables 1 and 2, in Experimental Examples 6 to 10, the height H of the position of the drawing furnace 5, the height h of the position of the plate-like portion 131, and the initial position of the moving mechanism 132 , and the final position of the moving mechanism 132 are different, but the other parameters are the same. Further, in Experimental Examples 6 to 7 and Experimental Example 9, the moving mechanism 132 was not moved during the drawing process, but in Experimental Examples 8 and 10, the moving mechanism 132 was moved during the drawing process. It is moved so as to approach the center of the tower 2 (position P). Furthermore, the height H of the position of the drawing furnace 5 in Experimental Example 6 is 10.5 m, that is, less than 12.0 m, whereas the height H of the position of the drawing furnace 5 in Experimental Examples 7 to 10 is 12.0 m or more.

In Experimental Example 6, the positional deviation of the drawing furnace 5 and the positional deviation of the pass line at the start and end of drawing, and the wire breakage frequency were all within a good range, so the evaluation was made A. On the other hand, in Experimental Examples 7 and 9, in which the height H of the position of the drawing furnace 5 is higher than that of Experimental Example 6, the displacement of the drawing furnace 5 and the displacement of the pass line at the start of drawing, Since the disconnection frequency and , deviate from the good range, the evaluation was set to C. In particular, in Experimental Example 9, in which the height H of the position of the drawing furnace 5 is the highest, the positional displacement of the drawing furnace 5 and the positional displacement of the pass line at the start of drawing are the largest, and the disconnection frequency is also the highest. . From this, it was confirmed that the positional deviation of the drawing furnace 5 at the start of drawing, the positional deviation of the pass line, and the frequency of wire breakage increased as the height H of the position of the drawing furnace 5 increased. . In addition, in Experimental Example 6, since the displacement of the drawing furnace 5 and the displacement of the pass line were already within the favorable range at the start of drawing, it was not necessary to move the moving mechanism 132 during the drawing process. was also confirmed.

On the other hand, Experimental Example 8 in which only the initial position of the moving mechanism 132 and the final position of the moving mechanism 132 differ from Experimental Example 7, and Experimental Example 9 in which only the initial position of the moving mechanism 132 and the final position of the moving mechanism 132 differ from Experimental Example 9. In 10, the positional deviation of the drawing furnace 5 and the positional deviation of the pass line at the start and end of drawing, and the wire breakage frequency were all within the good range, so the evaluation was given as A. The higher the height H at the position of the drawing furnace 5, the more effectively the first moment M1 is applied to the drawing tower 2. From these examples, the height H at the position of the drawing furnace 5 is 12 m or more. It has been confirmed that it is useful to apply the present disclosure when .

Next, Experimental Examples 11 to 13 will be described. As shown in Table 2, the initial position of the moving mechanism 132, the final position of the moving mechanism 132, the length of the optical fiber preform 6, and the fiber length are different, but other parameters are the same. . In Experimental Examples 11 and 12, the moving mechanism 132 was not moved during the drawing process. is moved so as to approach Furthermore, the fiber length in Example 11 is 788 km, ie less than 1000 km, whereas the fiber length in Examples 12 and 13 is 1002 km, ie greater than 1000 km.

In Experimental Example 11, the positional deviation of the drawing furnace 5 and the positional deviation of the pass line at the start and end of drawing, and the frequency of wire breakage were all within the good range, so evaluation was given as A. On the other hand, in Experimental Example 12, in which the fiber length is longer than that of Experimental Example 11, the displacement of the drawing furnace 5 at the start of drawing, the displacement of the pass line, and the disconnection frequency are out of the good range. Therefore, the evaluation was set to C. Therefore, it was confirmed that the longer the fiber length, the higher the misalignment of the drawing furnace 5 and the misalignment of the pass line at the start of drawing, and the frequency of disconnection. In addition, in Experimental Example 11, since the displacement of the drawing furnace 5 and the displacement of the pass line were already within the favorable range at the start of drawing, it was not necessary to move the moving mechanism 132 during the drawing process. was also confirmed.

On the other hand, in Experimental Example 13, which differs from Experimental Example 12 only in the initial position of the moving mechanism 132 and the final position of the moving mechanism 132, the positional deviation of the drawing furnace 5 and the positional deviation of the pass line at the start and end of drawing are , disconnection frequency, and the like are all within a good range, so the evaluation was set to A. The longer the fiber length of the spun optical fiber 7, the larger the optical fiber preform 6 and the larger the first moment M1. From these examples, when the fiber length is 1000 km or more, the present disclosure is applied. It was confirmed that this is useful.

Although the present disclosure has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present disclosure. Also, the number, positions, shapes, etc. of the constituent members described above are not limited to those in the above embodiment, and can be changed to suitable numbers, positions, shapes, etc. in carrying out the present disclosure.

In the second embodiment, the optical fiber manufacturing apparatus 1A is configured to include only the control unit 4, but may further include a control unit 40 having the same hardware configuration as the control unit 4.

In the above embodiment, the center of gravity 133a approaches the center (position P) of the drawing tower 2 as the movement mechanism 132 moves, but it may move away from the center of the drawing tower 2. For example, when the effective part of the optical fiber preform 6 has been drawn and a new optical fiber preform 6 is attached, it is preferable to move the center of gravity 133a away from the center of the drawing tower 2. FIG.

In the above embodiment, the movement mechanism 132 moves in the X-axis direction, but may also move in the Y-axis direction or the Z-axis direction.

In the above embodiment, the imparting mechanism 13 controls the second moment by moving the moving mechanism 132, but the second moment may be controlled by changing the weight of the imparting mechanism 13. good. For example, the weight of the applying mechanism 13 may be changed by putting a liquid or the like in a container provided with the applying mechanism 13 and gradually discharging the liquid from the container as the wire drawing progresses.

Although the above embodiments have been described using an optical fiber manufacturing apparatus having one or two drawing lines for one drawing tower, the present disclosure provides three or more drawing lines for one drawing tower. It can also be applied to an optical fiber manufacturing apparatus having a drawing line of .

Although the above embodiment has been described using a wire drawing furnace, the present disclosure is also applicable to resistance furnaces, induction heating furnaces, and the like.

1, 1A: Optical fiber manufacturing device 2: Drawing towers 3, 30:

Chucks

3a, 30a:

Chuck supporting parts

3b, 30b: Slide parts 4, 40: Control parts 5, 50: Drawing furnaces 6, 60: Optical

fibers Base material

6a, 60a: Support rod 7: Optical fiber 8, 80: Outer diameter measuring device 9, 90: Forced cooling device 10, 100: Coating device 11, 110: Directly below roller 12, 120: Winding device 13: Giving mechanism 14, 140: Capstan device 21: Ground part 131: Plate-like part 132: Moving mechanism 133: Weight body 133a: Center of gravity CR: Center lines D1, D2, D3, d2: Distance F: Floor surface H, h: Height M1, m1: first moment M2, m2: second moment M3: third moment P: position V: area

Claims

a drawing tower,
a drawing furnace mounted on the drawing tower for heating and melting an optical fiber preform to spin an optical fiber;
an imparting mechanism mounted on the drawing tower for imparting a second moment to the drawing tower in a direction opposite to the acting direction of the first moment imparted to the drawing tower by the optical fiber preform. ,
The optical fiber manufacturing apparatus, wherein the imparting mechanism can reduce the second moment as the optical fiber preform becomes smaller.
The imparting mechanism includes a moving mechanism capable of moving in a predetermined direction and a weight body supported by the moving mechanism,
2. The optical fiber manufacturing apparatus according to claim 1, wherein the center of gravity of said weight moves toward or away from the center of said drawing tower as said movement mechanism moves.
The drawing tower has a grounding part that is grounded on the surface on which the drawing tower is arranged,
3. The optical fiber manufacturing apparatus according to claim 2, wherein the center of gravity of said weight body is located outside the outer circumference of said ground portion when viewed from above.
The height of the position where the applying mechanism applies the second moment to the drawing tower is 0.8 times or more the height of the position of the drawing furnace. The optical fiber manufacturing apparatus according to any one of claims 1 to 3.
The optical fiber manufacturing apparatus according to any one of claims 1 to 4, wherein the drawing furnace has a height of 12 m or more.
heating and melting an optical fiber preform in a drawing furnace mounted on a drawing tower to spin the optical fiber;
A second moment in a direction opposite to the direction of action of the first moment applied to the drawing tower by the optical fiber preform is applied to the drawing tower while decreasing as the optical fiber preform becomes smaller. A method of manufacturing an optical fiber, comprising the steps of:
The optical fiber manufacturing method according to claim 6, wherein the second moment is reduced by moving the center of gravity of the weight toward or away from the center of the drawing tower.
The optical fiber manufacturing method according to claim 7, wherein the center of gravity of the weight body is moved outside the outer circumference of the grounding portion of the drawing tower when viewed from above.
9. The second moment is applied to the drawing tower at a height of 0.8 times or more the height of the drawing furnace. The optical fiber manufacturing method described.
10. The optical fiber manufacturing method according to any one of claims 6 to 9, wherein the optical fiber is spun for 1000 km or more per optical fiber preform while reducing the second moment.