JPS6041539A - Apparatus for removing automatically deposited product - Google Patents

Abstract

PURPOSE:To prevent clogging of a discharge pipe by excessive reaction product and to proceed reaction smoothly to cause a reaction in a reaction vessel by providing many small holes to discharge pipe for excessive reaction product fitted to the reaction vessel and ejecting gas from the pipe. CONSTITUTION:A seed bar 3 is suspended in a reaction vessel 1 and gaseous raw material is ejected from the bottom through an oxyhydrogen burner 2 and base material for optical fiber 4 is deposited to the tip of the seed bar 3 by causing flame hydrolysis. The excessive reaction product in the furnace is discharged from a discharge passage 5; many ejection holes 14 for gas are provided to the gas ejection pipe 12. The gas is fed from a gas feeding port 13 and ejected into the inside of the gas discharge pipe 12. The excessive reaction product is discharged together with the gas preventing clogging of the gas discharge pipe 12 due to deposition of the product on the inside surface of the gas discharge pipe 12. By this way, reaction conditions in the reaction vessel 1 are held always constant and variation of quality (distribution of refractive index) of the base material 4 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic deposit removal device that prevents reaction surpluses exhausted from a reaction vessel from depositing in an exhaust passage.

When supplying the raw materials and reaction medium necessary for the reaction into the reaction vessel to obtain the desired reactant, a reaction surplus is generated.
A discharge passage is generally provided for exhausting the reaction surplus by full pressure, suction, or natural flow. As such a reaction vessel, a reaction apparatus for producing an optical fiber preform by the VAD method is shown in FIG. As shown in the figure, a seed rod 3 is vertically suspended within the reaction vessel 1, and an oxyhydrogen flame burner 2 is installed on the bottom surface of the reaction vessel 1, facing the seed rod 3. Glass raw materials and the like are ejected from this oxyhydrogen flame burner 2 to cause a flame hydrolysis reaction, and the generated glass particles are deposited on a seed rod 3, and at the same time, the seed rod 3 is pulled up to produce a porous base material 4. ing. At this time, all of the glass raw materials, glass fine particles, etc. participate in the reaction and do not necessarily adhere to and accumulate on the seed rod 3. A discharge passage 5 is connected to the reaction vessel 1 to discharge the remainder as a reaction surplus. There is. This discharge path 5 is connected to a surplus treatment device (not shown), and most of the reaction surplus is sucked into the surplus treatment device through this discharge path 5.

However, since the reaction surplus immediately after the flame hydrolysis reaction is fine and has a high temperature, it is cooled when passing through the inside of the discharge passage 5.
It gradually adheres and accumulates on the inner wall of the exhaust passage 5, and finally the exhaust passage 5
It may even lead to blockage. What is particularly important in the method for producing an optical fiber base material by the VAD method is that the distribution of glass particles in the space between the oxyhydrogen flame burner 2 and the seed rod 3 is formed so that a predetermined refractive index distribution is obtained. ,
This distribution of glass particles is maintained without fluctuation for a predetermined period of time. However, as mentioned above, if the reaction surplus adheres and accumulates in the discharge path 5 as deposits 6 and the diameter of the discharge path 5 is pinched 6 and the discharge path 5 is blocked, the discharge amount of the reaction surplus changes, etc. The distribution of the fine particles cannot be maintained as described above, which not only makes it difficult to obtain a predetermined refractive index distribution, but also makes continuous production, which is a feature of the VAD method, impossible.

In this way, in the conventional VAD-based optical fiber base material reaction device, reaction surplus adheres and accumulates in the discharge path 5.
It was not possible to maintain the reaction conditions in the reaction vessel constant, and it was not possible to continuously produce an optical fiber preform having a predetermined refractive index distribution.

In view of the above circumstances, it is an object of the present invention to prevent reaction surpluses from adhering and accumulating in the discharge path, and to maintain constant reaction conditions within the reaction vessel. The structure of the present invention that achieves the purpose of saving firewood is that a gas outlet is disposed on the inner wall of the exhaust passage for exhausting the reaction surplus from the reaction vessel, and the gas outlet is communicated with a gas supply source. The present invention is characterized in that the reaction surplus is prevented from adhering to and depositing on the discharge channel.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The automatic deposit removal device of the present invention will be described in detail below based on embodiments shown in the drawings.

FIG. 2 shows an embodiment of the present invention. In the present invention, as in the embodiment shown in the same figure, gas is ejected to prevent the reaction surplus from adhering and accumulating.

That is, the exhaust pipe 12 connected to the reaction vessel (not shown) as a discharge path has a double pipe structure as shown in the figure.
A large number of gas jet ports 14 are provided in the inner wall of the inner tube over the entire surface thereof. A gas supply port 13 is provided protruding from the exhaust pipe 12, and the gas supply port 3 is connected to a gas supply source (not shown) via a pipe or the like. Further, an exhaust pipe 11 is interposed between the exhaust pipe 12 and a surplus processing device (not shown). Therefore, from the reaction vessel to the exhaust pipe 1
2. When sucking the reaction surplus into the surplus processing device through the 11 Wr, if gas is supplied from the gas supply source to the exhaust pipe 12 through the gas supply port 13 and the gas is ejected from the gas outlet 14, the reaction surplus can be removed. will not be blown away and deposited on the inner wall of the exhaust pipe 12. Further, as shown by the arrow in the figure, the direction of gas ejection from the gas ejection port 14 is inclined toward the suction direction of the reaction surplus, which can contribute to improving the suction effect. The type of gas used is not particularly limited, and the method of ejecting it may be constant or intermittent. Furthermore, when gas is ejected intermittently, reaction surpluses adhere to and accumulate on the inner wall during interruption, but these deposits are blown away when ejection is restarted and can be quickly removed.

As described above in detail based on the embodiments, in the present invention, a gas outlet is provided on the inner wall of the discharge passage, and the gas is ejected from the gas outlet to blow off the reaction surplus. Reaction surplus was often deposited in the exhaust channel. Therefore, the reaction conditions inside the reaction vessel were kept constant without changing the exhaust conditions such as the exhaust amount.

In particular, when the present invention 1 is applied to a reaction device using an optical fiber base material using the VAD method, the exhaust conditions remain unchanged, so the distribution of glass particles in the space from the oxyhydrogen flame burner to the seed rod remains constant without time fluctuations. It becomes possible to continuously manufacture an optical fiber base material having a predetermined refractive index distribution.

[Brief explanation of drawings]

FIG. 1 is a schematic structural diagram of a reaction device for an optical fiber base material using the conventional VAD method, and FIG. 2 is a sectional view of an embodiment of the automatic deposit removal device of the present invention. In the drawing, 11 and 12 are exhaust pipes, 13 is a gas supply port, and 14 is a gas jet port. Patent applicant: Sumitomo Electric Industries, Ltd. agent Patent attorney: Shibu Mitsuishi (and one other person) Figure 1 Figure 2

Claims (1)

[Claims] In a discharge passage for discharging reaction surplus from the reaction vessel, a gas outlet is disposed on the inner wall of the discharge passage, and the gas outlet is communicated with a gas supply source to prevent the reaction surplus from adhering to the discharge passage. An automatic deposit removal device that completely prevents deposits.