JPH0449154Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an apparatus for coating a glass optical fiber (hereinafter simply referred to as an optical fiber) with a metal.

[Prior Art] Optical fibers coated with metal such as A (hereinafter referred to as metal-coated optical fibers) have superior heat resistance compared to optical fibers coated with organic substances, and are impermeable to moisture, so they can withstand high temperatures, It has the advantage of being usable even in humid environments, and its use is progressing. This metal-coated optical fiber was manufactured using the equipment described below.

FIG. 4 is a schematic longitudinal cross-sectional view of a conventional manufacturing apparatus for metal-coated optical fiber, in which 31 is a base material of the optical fiber, 32 is a heating furnace for heating the base material 31, and the base material 31 is heated. It is heated in a furnace 32 and drawn into an optical fiber 33.

Further, 34 is a cylindrical iron or carbon crucible having a die portion 34b protruding from its bottom side surface. Crucible portion 34a forming the main body of crucible 34
The metal coating the optical fiber 33 is melted and stored, and the die part 34b to which the molten metal is supplied from the crucible part 34a has a die (not shown) having a diameter slightly larger than the diameter of the optical fiber to be inserted. ) is included. Further, the crucible 34 is the crucible portion 3
The crucible 4a is surrounded by a heat insulating material 35 incorporating a heater (not shown) for heating the crucible 4a, and the temperature inside the crucible 34 is maintained at a high temperature. Furthermore, an inert gas (such as Ar) (not shown) is placed above the crucible portion 34a.
An inert gas supply pipe 37 with a pressure gauge 36 in the middle is connected to the source, and the inert gas is supplied to the crucible part 34a to prevent oxidation of the molten metal.
The gas is introduced into the crucible portion 34a and is discharged from an inert gas discharge pipe 38 connected to the upper part of the crucible portion 34a.

The optical fiber 33 inserted through the upper die of the die section 34b comes into contact with the molten metal supplied from the crucible section 34a within the die section 34b, and due to the temperature difference between the optical fiber 33 and the molten metal, the optical fiber 33 Metal is adhered to the fiber to form a metal-coated optical fiber 33', which passes through a lower die and is wound up by a winder 39. In the figure, 40 and 41 are thermocouples for measuring the temperatures of the crucible portion 34a and the die portion 34b.

[Problems to be solved by the invention] In the device as described above, the length of contact between the optical fiber 33 and the molten metal is constant depending on the distance between the upper and lower dies, and therefore it is difficult to control the amount of metal adhesion. It had the drawback of being difficult. Furthermore, when the diameter of the optical fiber to be drawn changes, it is necessary to replace a pair of upper and lower dies at the same time, and in this case there is a problem in workability in that center alignment of the upper and lower dies is troublesome.

The present invention was developed in view of the above circumstances, and its purpose is to use a single die in the die section, so that when the diameter of the optical fiber to be drawn changes, the die only needs to be replaced. A glass optical fiber that is easy to replace, improves maintenance efficiency, and allows you to control the amount of metal adhering to the optical fiber by changing the size of the molten metal supply hole in the die. An object of the present invention is to provide a metal coating device.

[Means for Solving the Problems] A device for metal coating a glass optical fiber according to the present invention inserts the glass optical fiber into a die portion that stores molten metal supplied from a crucible portion, and coats the optical fiber with the metal. In an apparatus for coating the metal on
The die section is equipped with one die made of ceramic, and a glass optical fiber is inserted into the die section that stores the molten metal supplied from the crucible section.
In the apparatus for coating the optical fiber with the metal, the die section includes one die made of ceramic, and the die has a die hole through which the optical fiber is inserted and a melting hole that is orthogonally connected to an intermediate portion of the die hole. A device for metal coating a glass optical fiber, characterized by having a metal supply hole.

[Function] Since the device of the present invention has only one die, it is easy to replace the die, and the efficiency of maintenance management is improved.Furthermore, the size of the molten metal supply hole provided in the die can be changed. This makes it possible to control the amount of metal adhering to the optical fiber.

[Examples] The present invention will be described below based on drawings showing examples thereof. FIG. 1 is a schematic longitudinal cross-sectional view of an optical fiber metal coating device according to the present invention (hereinafter referred to as the device of the present invention). Like the conventional device shown in FIG. 4, 1 in the figure indicates the base material of the optical fiber; 2 is the heating furnace, 3 is the base material 1
An optical fiber is shown drawn from. Further, the crucible 4 is composed of a substantially cylindrical crucible portion and a die portion 24 connected to the crucible portion 14, which can be separated from each other, and both are made of ceramic such as alumina or silicon nitride. The configuration will be explained below.

A part of the bottom surface of the crucible part 14 is a thick base part 14
a, and a thermocouple 10 is attached to the base portion 14a.
A hole 14b is provided for inserting a terminal. Further, the upper lid 14c of the crucible portion 14 has screws 14d, 1
4d, and an inert gas supply pipe 7 and an inert gas discharge pipe 8 each having a pressure gauge 6 in the middle open in the upper lid 14c, as in the conventional device. The introduction into the crucible portion 14 prevents oxidation of the molten metal. Further, a cylindrically protruding die holder attachment portion 14e is provided on the bottom side surface of the crucible portion 14, and a flange 14f is formed on the die holder attachment portion 14e.

The die section 24 is composed of a cylindrical die holder 25 that is communicatively connected to the die holder attachment section 14e of the crucible section 14, and a die 26 that is fitted into the cylindrical die holder 25. The base end of the die holder 25 has a cylindrical shape with the same diameter as the die holder attachment part 14e, and a flange 25a is formed at the base end to be fixed to the flange 14f with screws 12, 12. Further, a die fitting hole 25b for fitting the die 26 is formed in the center of the die holder 25 in the longitudinal direction. The shape of the die fitting hole 25b is different between the upper 3/4 portion and the lower 1/4 portion. The upper part has a stepped rectangular shape with a slightly elongated central part on the flange 25a side in plan view, and is cut across the entire radial direction of the die holder 25. On the other hand, the lower portion is a circular hole having a diameter smaller than the diameter of the die holder 25. Therefore, the base end and the distal end of the die holder 25 are connected at the lower 1/4 portion. Furthermore, the tip is thick and has a hole 25c formed in its axial center for inserting the terminal of the thermocouple 11.

FIG. 2 is a plan view of the die portion 24, and FIG. 3 is an enlarged vertical sectional view of the die 26. dice 26
has a rectangular parallelepiped shape whose width is equal to the outer diameter of the die holder 25, and has a protrusion 26a on the upper surface of the end,
Further, a circular hole 26b is cut in the center of the lower part. Further, a hole 26c for supplying molten metal is provided in the axial center portion of the die 26 in the fitted state.
Furthermore, a die hole 26d is formed concentrically with the hole 26b, communicating orthogonally with the hole 26c, and through which an optical fiber is inserted from the upper surface of the die 26 to the hole 26b. Then, the die 26 as described above is fitted into the die fitting hole 25b of the die holder 25, and the molten metal in the crucible portion 14 is transferred to the die holder 2.
5 and is supplied to the hole 26c.

In addition, the heat insulating material 5 incorporating a heater (not shown) is connected to the crucible 4 (the crucible part 14 and the die part 2).
4), and the inside of the crucible 4 is maintained at a high temperature. Further, the ends of thermocouples 10 and 11 are inserted into the hole 14b and the hole 25c, respectively, so that the temperatures of the crucible portion 14 and the die portion 24 are measured.

The drawn optical fiber 3 is inserted into the die hole 26 of the die 26 fitted into the die holder 25.
d is inserted through the hole 26c and comes into contact with the molten metal supplied from the crucible part 14, and due to the temperature difference between the optical fiber 3 and the molten metal, the metal is adhered to the circumferential surface of the optical fiber 3, and the metal A coated optical fiber 3' is produced and wound on a winder 9.

In the present invention, the die part is further divided into a die holder and one die, so when the diameter of the optical fiber is changed, only the die in the die part needs to be replaced.

In addition, controlling the amount of metal adhering to the surface of the optical fiber depends on the temperature difference between the optical fiber and the molten metal, the linear speed, etc., but it also depends on the contact length of the molten metal on the optical fiber. By varying the size of the feed hole, this contact length can be varied, thereby controlling the amount of metal adhesion.

[Effects] As described in detail above, in the present device, one die is provided in the die section, so when changing the diameter of the optical fiber, only one die needs to be replaced, and workability is good. Further, by changing the size of the molten metal supply hole provided in the die, the amount of metal adhesion can be controlled.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view of an optical fiber metal coating device according to the present invention, FIG. 2 is a plan view of the die portion, FIG. 3 is an enlarged vertical cross-sectional view of the same die, and FIG.
The figure is a schematic vertical cross-sectional view of a conventional optical fiber metal coating device. 1... Base material, 2... Heating furnace, 3... Optical fiber, 3'... Metal coated optical fiber, 4... Crucible,
10, 11... Thermocouple, 14... Crucible part, 14
c...Top lid, 24...Dice part, 25...Dice holder, 26...Dice, 26c... Molten metal supply hole, 26d...Dice hole.

Claims (1)

[Claims for Utility Model Registration] An apparatus for inserting a glass optical fiber into a die section for storing molten metal supplied from a crucible section and coating the optical fiber with the metal, wherein the die section is made of ceramic. An apparatus for metal coating a glass optical fiber, comprising one die, the die having a die hole through which the optical fiber is inserted, and a molten metal supply hole communicating orthogonally to an intermediate portion of the die hole. .