JPS58659Y2 - Raw material supply equipment for manufacturing optical fiber base material - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a supply device for producing optical fiber preforms, and more specifically, the present invention relates to an optical fiber preform production device that prevents pressure fluctuations in the supply pipeline and enables stable supply of vaporized glass raw materials. The present invention relates to a supply device.

Conventionally, this type of device fills silicon tetrachloride, which is a raw material for glass, and doping substances, such as germanium tetrachloride, phosphorus oxychloride, boron tribromide, etc., into each raw material container.
It was configured to bubble a flow-controlled carrier gas, such as argon gas, into the liquid glass raw material in each container to obtain the desired vapor of each of the raw materials.

FIG. 1 is a schematic cross-sectional view showing a specific example of such an apparatus, in which 1 is a container for liquid frit, 5 is a bubbler, and 9
represents the outlet of the vaporous frit.

In this container 1, a carrier gas is blown out from a bubbler 5 with a controlled flow rate and bubbles the liquid glass raw material to obtain a vaporized glass raw material. Air bubbles become suspended, and these air bubbles begin to blow out onto the surface of the liquid frit.

As a result, the pressure inside the liquid frit container 1 changes instantaneously according to the amount of fine bubbles, and the vaporized frit outlet 9
Pressure fluctuations are transmitted up to.

This phenomenon hinders the stable supply of vaporized glass raw materials such as silicon tetrachloride and becomes a major cause of fluctuations in the refractive index of the manufactured optical fiber base material.

The present invention was made to eliminate these drawbacks, and its purpose is to provide a raw material supply for optical fiber base material production that can prevent pressure fluctuations in the supply pipe line and stably supply vaporized glass raw material. The purpose is to provide equipment.

To summarize the present invention, the raw material supply device for producing an optical fiber base material of the present invention is an optical fiber material supplying device for producing an optical fiber preform by filling a container with a liquid glass raw material, bubbling a carrier gas into the container, and supplying a mixture of the vaporized raw material and the carrier gas. This raw material supply device for producing a base material is characterized in that a buffer tank 19 is provided in a supply pipe line 18 for the mixture of the vaporized glass raw material and carrier gas.

In the vaporized frit supply system equipped with one buffer tank according to the present invention, minute pressure fluctuations in the liquid frit container (hereinafter referred to as raw material container) caused by carrier gas bubbling are prevented, and the steam is kept at a constant pressure. As a result, fluctuations in the refractive index Δn of the optical fiber preform to be manufactured can also be significantly reduced.

The buffer tank in the present invention is a type of buffer device that maintains the pressure in the supply pipe line constant, and this tank is provided in the pipe line on the steam and gas outlet side of the raw material container.

Although it is possible to some extent to buffer pressure fluctuations by widening the upper space of the liquid glass raw material filling part of the raw material container,
This is not desirable because the capacity of the raw material container becomes large.

In addition, one buffer tank in the present invention can be provided in the raw material supply pipe line of each raw material container, but as shown in FIG. The purpose can be achieved with one buffer tank per raw material container.

Furthermore, in the buffer tank of the present invention, for example, a cylindrical partition plate as shown in FIG. The shape of the partition plate can also be selected as appropriate.

In this invention, an inert gas such as argon, helium, or nitrogen is used as a carrier gas, and by controlling the flow rate and introducing it into each raw material container and bubbling it, a predetermined amount of each vaporized glass raw material is transferred to an optical fiber. It can be supplied to base material manufacturing equipment.

Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 2 is a schematic cross-sectional view showing a specific example of the raw material supply device for manufacturing optical fiber preforms of the present invention, in which 2, 3, and 4 are raw material containers, 6, 7, and 8 are bubblers, and 10 11 is silicon tetrachloride, 11 is germanium tetrachloride, 12 is phosphorus oxychloride, 13 is air bubbles, 14, 15 and 16 are carrier gas introduction pipes, 17 is carrier gas, 18 is supply pipe, 19 is a buffer tank, 20 21 indicates a vaporous frit outlet and 21 indicates a vaporous frit outlet.

Silicon tetrachloride 10 and doping substances phosphorus oxychloride 12 and germanium tetrachloride 11 were filled into raw material containers 2, 3, and 4, respectively.

One buffer tank 19 has a length of 4QQmm and a diameter of 10
0mm glass tube with length 350mm and diameter 50m
The structure used was one in which one end of a glass tube of No. m was welded to the upper part of the tank.

Each raw material container 2, 3, and 4 and one buffer tank 19 have a diameter of lQ.
It was connected with a 18 mm tube (Teflon tube).

Also, using argon gas as the carrier gas 17,
Control the flow rate to 0 cc/min, and open the carrier gas introduction pipe 14.
15 and 16 are respectively flowed into bubblers 6, 7 and 8 in raw material containers 2.3 and 4, each raw material is bubbled, and passed through a supply pipe 18 to a buffer tank 19 as a vapor at the outlet of the vaporized glass raw material. It led to 20.

At this time, almost no pressure fluctuation was observed on the outlet 20 side.

The fluctuation in the refractive index Δn of the optical fiber base material produced from this vaporous glass raw material was 0.05% or less.

For comparison, an experiment was conducted using a raw material container without a buffer tank 19, but in this case, the pressure changed instantaneously, and the fluctuation of the refractive index △n of the obtained optical fiber base material was The increase was 0.2%.

As explained above, according to the present invention, by providing one buffer tank, the influence of minute pressure fluctuations in the raw material container caused by bubbling of carrier gas is improved, and the vaporized glass raw material is always kept at a constant pressure. Fluctuations in the refractive index of the optical fiber base material manufactured using this raw material can also be minimized.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing one specific side of a conventional raw material supply lid for manufacturing an optical fiber preform, and FIG. 2 shows a specific example of the raw material supply device for manufacturing an optical fiber preform of the present invention. FIG. 1.2.3 and 4... Raw material container, 5, 6.7 and 8... Bubbler, 9 and 20... Vaporous frit outlet, 10... ...Silicon tetrachloride,
11... Germanium tetrachloride, 12...
・Phosphorus oxychloride, 13... air bubbles, 14.15
and 16...carrier gas introduction pipe, 17...
...Carrier gas. 18... Supply pipe line, 19... One buffer tank, 21... Vaporous glass raw material.

Claims (1)

[Scope of utility model registration request] In a raw material supply device for manufacturing an optical fiber preform, a liquid glass raw material is filled into a container, a carrier gas is bubbled into the container, and a mixture of the vaporous glass raw material and the carrier gas is supplied. A raw material supply device for manufacturing an optical fiber base material, characterized in that a buffer tank is provided in a supply pipe line.