JPH06298548A - Optical fiber spinning apparatus - Google Patents

Abstract

PURPOSE:To provide an optical fiber-spinning apparatus capable of efficiently cooling an optical fiber at a low cost. CONSTITUTION:In an optical fiber-spinning apparatus provided with a cooling device 1 for cooling an optical fiber by feeding helium gas or a mixed gas of helium and other gas before spinning an optical fiber and applying UV-cured or thermosetting type resin to the spun optical fiber, a changeover device 13 for stopping fed of helium gas or a mixed gas of helium and other gas or changing over from feed of the gas to feed of other gas is provided in the cooling device 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber spinning device capable of efficiently cooling an optical fiber after spinning the optical fiber.

[0002]

2. Description of the Related Art Conventionally, when spinning an optical fiber, a method as shown in FIG. 2 is generally used. That is, first, the optical fiber preform is drawn while being melted in the heating furnace 18 at about 2000 ° C., and the obtained optical fiber 19 is passed through the cooling device 1 to be cooled to a temperature of about 100 ° C. or less. Next, the coating device 20 coats a UV or thermosetting resin, the resin is cured through a crosslinking device 21 such as a UV irradiation furnace or a heating furnace, and the obtained optical fiber is taken up by a take-up device 22 and a winding device 23. To collect.

By the way, the cooling device 1 has a structure in which water is flowed around the cooling cylinder through which the optical fiber 19 passes to cool it, and a refrigerant gas such as nitrogen is supplied to the inside of the cooling cylinder. There is. However, when nitrogen or the like is used as the refrigerant gas, the flow velocity must be increased in order to improve the cooling effect, and the optical fiber is likely to vibrate. Therefore, recently, helium gas having high thermal conductivity has been used instead of nitrogen or the like.

[0004]

By the way, in recent years, with the increase in the speed of optical fiber spinning, there has been a problem that it is difficult to avoid an increase in the size of a cooling device and an increase in the amount of refrigerant gas used. In particular, when the helium gas as described above is used as the refrigerant gas, the helium gas is originally expensive, so that the apparatus cost and the manufacturing cost are significantly increased, and the merit of speeding up is reduced.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical fiber spinning apparatus capable of efficiently cooling an optical fiber at low cost.

[0006]

In order to achieve such an object, the present invention provides a helium gas or a mixture of helium and other gas before spinning an optical fiber and coating a UV or thermosetting resin. In an optical fiber spinning device equipped with a cooling device for supplying a mixed gas to cool an optical fiber, the cooling device stops supplying helium gas or a mixed gas of helium and another gas, or supplies another gas. It is characterized in that a switching device for switching is provided.

[0007]

In the optical fiber spinning apparatus of the present invention, the helium gas or the mixed gas of helium and other gas is supplied by the switching device only during operation or when the linear velocity is high, and when not in operation or during line operation. When the speed is low, switching the switch to stop the gas supply or supplying other gas such as nitrogen enables efficient cooling and reduces the amount of expensive helium gas used. Therefore, the manufacturing cost can be suppressed at low cost.

[0008]

The present invention will be described in detail below. FIG. 1 shows an example of a cooling device used in the optical fiber spinning device of the present invention. The cooling device 1 includes a cooling tube 2
The water circulation path 3 and the refrigerant gas supply unit 4 are generally configured.

The cooling cylinder 2 is a cylindrical cylindrical body through which an optical fiber after drawing is passed, and it is preferable that the cooling cylinder 2 is made of copper, aluminum, or an alloy thereof having good thermal conductivity.

The water circulation path 3 is tightly wound around the cooling cylinder 2 and passes through a pipe 5 for passing cold water, and a controller 6 for connecting both ends of the pipe 5 and controlling the temperature of the cold water at a constant level. Consists of.

The refrigerant gas supply unit 4 is connected to the cooling pipe 2 through a supply pipe 7 for supplying the cooling gas and two branch pipes 8 and 9 branched from the supply pipe 7. A helium gas tank 10 and a nitrogen gas tank 11 are provided. The tip of the supply pipe 7 is disposed inside the cooling cylinder 2 and serves as a supply port 7a for supplying the refrigerant gas. Two
The two branch pipes 8 and 9 are connected to each other by a connecting pipe 12. Then, in the middle of the branch pipe 8 and at the connection position with the connection pipe 12, or at least at the upstream position from this connection position, a switch 13 for switching or stopping the supply gas.
Are arranged. The switch 13 may be of a manual type, or may be of an automatic type which is connected to a control device (not shown) and automatically switches according to the linear velocity of the optical fiber. Further, flow meters 14 and 15 for controlling the gas flow rates of the two branch pipes 8 and 9 are arranged.

Filters 16 and 17 for removing impurities in each gas are arranged near the outlets of the helium gas tank 10 and the nitrogen gas tank 11.

The cooling device 1 thus constructed is arranged immediately below the heating furnace 18, as shown in FIG.

Next, the spinning method of the optical fiber and its function and effect will be described. The optical fiber preform is drawn in a heating furnace 18 at about 2000 ° C. while being drawn, passed through a cooling device 1 and cooled to a temperature of about 100 ° C. or less.

When the drawn optical fiber 19 passes through the inside of the cooling tube 2, the optical fiber 19 is gradually cooled from the surroundings by the cold water circulating in the water circulation passage 3 and supplied from the refrigerant gas supply section 4. It is forcibly cooled by the refrigerant gas. Here, for example, when not operating or when the linear velocity is low, the branch pipe 8 is closed by the switch 13 so that only nitrogen gas flows through the branch pipe 9 to the supply pipe 7. As a result, the cooling cylinder 2 is cooled only by the nitrogen gas, so that the use of expensive helium gas can be avoided and the manufacturing cost can be reduced. Further, for example, during operation or when the linear velocity is high, the branch pipe 8 is opened by the switching device 13 so that the mixed gas of helium gas and nitrogen gas flows into the supply pipe 7. As a result, cooling is performed with a gas containing helium gas, which has a high thermal conductivity, and a high cooling effect can be expected. For this reason,
It is also possible to reduce the size of the device and reduce the cost of the device. The mixing ratio of helium gas and nitrogen gas can be appropriately changed by adjusting the flow meters 14 and 15.

Further, since the filters 16 and 17 are arranged in the respective branch pipes 8 and 9 as described above, a gas with a small amount of impurities always flows in the pipes, so that the inside of the cooling device 1 is kept clean. You can Therefore, the occurrence of troubles due to impurities can be suppressed, and the maintenance of the device can be performed easily.

Next, the cooled optical fiber 19 is passed through a coating device 20, where it is coated with UV or thermosetting resin. After that, the resin is cured through a crosslinking device 21 such as a UV irradiation furnace or a heating furnace, and the obtained optical fiber is collected by a drawing device 22 and a winding device 23.

The present invention is not limited to the above embodiment,
Specific constituent requirements can be changed as appropriate. For example, a switching device may be arranged in the middle of the branch pipe 9 and the supply gas may be adjusted by operating both the switching device 13 provided in the middle of the branch pipe 8. In this case, it is possible to supply only helium gas, and more efficient cooling can be performed. In addition to the positions shown in FIG. 1, the filters 16 and 17 may of course be arranged in the middle of the supply pipe 7 as long as they can remove impurities in the supply gas.

Next, the effects of the present invention will be clarified by showing concrete examples. (Example) Using the cooling device having the configuration shown in FIG. 1, the cooling device was placed 50 cm below the heating furnace. The cooling tube of the cooling device is
The diameter was 10 mm and the length was 2000 mm. The drawing of the optical fiber was carried out at a linear velocity of 300 m / min, but when not in operation and at a low linear velocity of 80 m / min or less, only nitrogen gas was cooled at 8 liters / min to obtain a linear velocity of 80 mmin or more during operation. At high speeds, helium gas 6 liter / m by operating the switch and flow meter
In, nitrogen gas was adjusted to 2 l / min, and wire drawing was performed.

The optical fiber temperature was suppressed to about 70 ° C. or less even when the optical fiber was drawn at 300 m / min, and there was no problem in the subsequent coating work. The line runout of the optical fiber was small, about 0.05 mm or less.

(Comparative Example) The cooling was performed only with nitrogen gas regardless of the linear velocity. In this case, a flow rate of at least 70 liters / min or more is required, and the line runout is remarkable,
It was impossible to draw a line.

[0022]

As described above, according to the optical fiber spinning apparatus of the present invention, the switching device of the cooling device is appropriately operated depending on whether or not the vehicle is in operation, the magnitude of the linear velocity, and the like. Since the use gas can be switched, it is possible to efficiently perform cooling to downsize the apparatus, and reduce the amount of expensive helium gas used to suppress the manufacturing cost at a low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a cooling device in an optical fiber spinning device of the present invention.

FIG. 2 is a cross-sectional view illustrating a method for spinning an optical fiber.

[Explanation of symbols]

 1 Cooling Device 4 Refrigerant Gas Supply Unit 13 Switching Device 16, 17 Filter 19 Optical Fiber

Claims (2)

[Claims] 1. A cooling device for cooling an optical fiber by supplying helium gas or a mixed gas of helium and another gas before spinning an optical fiber and coating a UV or thermosetting resin. In the optical fiber spinning device, the cooling device is provided with a switching device that stops the supply of helium gas or a mixed gas of helium and other gas, or switches to the supply of other gas. apparatus. 2. The optical fiber spinning device according to claim 1, wherein the cooling device is provided with a filter for removing impurities in the helium gas or a mixed gas of helium and another gas. .