JPH0348191Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Field of Application> This invention relates to a matzuru used in manufacturing a base material for optical fiber.

<Prior art> Conventionally, as shown in FIGS. 3 and 4, a combustion burner 2 is provided diagonally upward on one side of the bottom of a Matsufuru 1 having a circular horizontal cross section, and an exhaust gas is provided on the other side of the lower part of the Matsufuru 1. A pipe 3 is provided, and the glass raw material and fuel are ejected from the burner 2, and glass particles are formed by a flame hydrolysis reaction or oxidation reaction onto the rod-shaped starting material 4 rotating at the center of the upper part of the matsuful 1. The glass particles are deposited to grow a porous glass base material 5.

The purpose of growing the porous glass base material 5 within the pine tree 1 as described above is to suppress disturbances in the outside air or temperature fluctuations, and to form the flame 6 stably.

<Problem to be solved by the invention> In the method described above, when increasing the amount of glass raw material input into the combustion burner 2 for the purpose of high-speed synthesis or increasing the size of the porous glass base material 5, it is difficult to efficiently use the raw material. In order to achieve a good reaction and to stably produce the base material, it is necessary to increase the fuel flow rate.

However, with the increase in fuel flow rate, fuel burner 2
The length of the flame 6 formed by this becomes considerably long,
In the conventional pine tree 1 having a circular cross section as shown in FIG. 4, the flame 6 emitted from the burner 2 hits the side wall of the pine tree on the exhaust pipe 3 side.

For this reason, the side wall of the pine tree that is hit by the flame 6 becomes locally overheated, causing thermal distortion.

The only way to solve this problem is to make the Matsufuru itself larger, while keeping the conventional circular cross-section Matsufuru, but if you make the whole Matsufuru larger, the space occupied by the Matsufuru will increase, causing problems with the equipment. .

In addition, the space on the burner side that is not overheated becomes larger, the effect of the matsufuru that tried to stabilize the flame is lost, and the flame fluctuates more.

<Means for solving the problem> This invention was made to solve the above problem, and it is a method to extract gaseous glass raw material from a combustion burner installed obliquely to the vertical direction inside the Matsuful. In an apparatus that manufactures a porous glass base material by ejecting and hydrolyzing in a flame and depositing the resulting granular glass on a rotating starting material, the cross-sectional shape of the Matsufuru is rectangular or elliptical. The starting material has a horizontally elongated shape, the axis of rotation of the starting material is eccentric to one of the long sides from the center of the cross section of the matsufuru, and the combustion burner is arranged so that its central axis is along the long side and the jet nozzle is are installed in a short distance region between the rotation axis and the Matsufuru side wall in the eccentric direction with the combustion burners facing in the direction of the rotation axis, and an exhaust port is provided in the Matsufuru side wall facing the installation part of the combustion burner. It is something that

<Function> As described above, this invention makes the rotational axis of the starting material eccentric to one side in the long side direction from the center of the cross section of the matsufuru, and also sets the combustion burner so that its center axis is along the long side direction and Since the jet ports are installed in a short distance area between the rotation axis and the Matsufuru side wall in the eccentric direction with the jet ports facing each other in the direction of the rotation axis, it is possible to increase the amount of glass raw material fed into the burner and to reduce the amount of fuel. The flow rate can be increased and the flame can be made longer and more stable.

Therefore, it is possible to synthesize the porous glass base material at high speed or to increase the size of the porous glass base material. Further, even if the flame is made long in this way, there is no risk that the tip of the flame will hit the surface of the matsufuru and cause local overheating.

〈Example〉 Figures 1 and 2 show an example of this invention. Reference numeral 11 is a matsufuru, and as shown in Figure 2, the cross section is rectangular or oval, and the flame is elongated. It is made of metal and extends in the longitudinal direction.

13 is a starting material whose rotational axis M' is 1/3 along the long side direction P of the Matsufuru 11 from the burner 12 side.
It is eccentric by L at the position.

A burner 12 is fixed near one end of the bottom of the matsufuru 11. This burner 12 is installed in a short distance region S between the rotation axis M' in the eccentric direction of the starting material 13 (right side in FIG. 1) and the right side wall of the Matsufuru 11, and its central axis R is Along the long side direction P, and the jet nozzle 12a is the rotation axis.
They are facing in the M′ direction. As a result, the spout 1
2a is oriented diagonally upward toward the center M of the pine full 11.

Reference numeral 14 denotes an exhaust pipe, which is provided near the bottom of the side wall of the exhaust pipe on the side facing the burner 12.

In the above example, when the glass raw material and fuel are injected and burned from the burner 12 and the flame 15 is applied to the starting material 13 and the starting material 13 is rotated, the glass particles formed by the flame hydrolysis reaction or the oxidation reaction are It adheres to the starting material 13 and grows as a porous glass base material.

With this action, even if the flame 15 is enlarged by increasing the amount of glass raw material and fuel supplied to the burner 12, there is no fear that the tip of the flame 15 will hit the side wall of the matsufuru 11.

Conventionally, the local surface temperature rose to 300°C to 400°C due to the burner flame, but in the above embodiment, it was possible to reduce it to 150°C to 200°C.

Moreover, flame safety was not compromised.

<Effects> As mentioned above, this invention makes the cross section of the Matsufuru horizontally elongated, makes the rotation axis of the starting material and the porous glass base material eccentric to one of the long sides from the center of the cross section of the Matsufuru, and , because the combustion burner was installed in a short distance region between the rotation axis and the pine full side wall in the eccentric direction, with its central axis along the long side direction and the jet nozzle facing the rotation axis direction. Even if the amount of glass raw materials and fuel is increased to make the flame larger and the porous glass base material is synthesized at high speed or made larger, there is a possibility that the flame will touch the side wall of the matsufuru and cause the side wall to locally overheat. That's not it.

In addition, by making the cross section of the matsufuru rectangular or elliptical, which has a long axis and a short axis, it is possible to prevent the above-mentioned overheating without impairing the stability of the flame. .

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional side view showing one embodiment of the Matsufuru of this invention, Fig. 2 is a cross-sectional plan view taken along line A-A of the same, Fig. 3 is a longitudinal sectional side view of the conventional Matsufuru, and Fig. 4
The figure is a cross-sectional plan view taken along line B-B of the same as above. 11...Matsuful, 12...Burna, 12a...
...Ejection port, 13...Starting material, 14...Exhaust pipe, 1
5...Flame, 16...Porous glass base material, M...
Center of Matsuful, M'...Rotation axis of starting material, L
... Eccentricity of the starting material, P ... Long side direction of Matsufuru, R ... Central axis of the burner, S ... Short distance region.

Claims (1)

[Scope of utility model registration request] Inside the Matsufuru 11, a gaseous glass raw material is ejected from a combustion burner 12 installed diagonally upward with respect to the vertical direction, and is hydrolyzed in a flame. In an apparatus for producing a porous glass preform by depositing the starting material 1 on the starting material 1, the cross-sectional shape of the starting material 11 is made into an oblong shape such as a rectangle or an ellipse.
3's rotation axis M' is the center M of the cross section of Matsuful 11
Therefore, while making the combustion burner 11 eccentric in one of the long side directions P, the combustion burner 11 is set in such a state that its central axis R is along the long side direction P and the jet nozzle 12a is opposite to the rotation axis direction. rotation axis
A Matsufuru for manufacturing an optical fiber base material, characterized in that it is installed in a short distance region S between M' and a Matsufuru side wall, and an exhaust port 14 is provided in the Matsufuru side wall facing the installation part of the combustion burner 11.