JPH01219030A - Production of cylindrical transparent quartz glass ingot - Google Patents

Abstract

PURPOSE:To obtain a cylindrical transparent quartz glass ingot in good yield by spraying the quartz crystal powder atomized by a burner onto a refractory head rotating at a constant speed to deposit the powder on the head, and fixing the thickness of the deposited molten quartz glass. CONSTITUTION:The quartz crystal powder atomized by the burner (4) is sprayed onto the freely rotatable refractory head (1), melted, and deposited. The upper- end position of the molten deposited quartz glass (9) is detected (by a television camera 10, etc.), and the thickness (l) of the deposit is fixed by controlling the flow rate of the gas injection from the burner (4). The cylindrical transpar ent quartz glass (11) flows down from the head (1), and solidifies. The solidified glass (11) is rotated, supported by the refractory supporting plate (6), and sent downward at a constant speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a cylindrical transparent quartz glass ingot, which is a raw material ingot for manufacturing transparent quartz glass tubes and the like.

[Conventional technology]

Conventionally, as a method for manufacturing the above-mentioned ingot, for example, the method described in Japanese Patent Publication No. 45-21393 is known.

This manufacturing method involves rotating a vertical quartz glass tube, spraying fused quartz powder in the form of a mist onto the surface of the quartz glass tube within the flame plane, and melting and depositing the fused quartz powder onto the quartz glass tube. This is a method of forming a glass layer.

[Problem to be solved by the invention]

However, according to the above conventional manufacturing method, although the inner diameter of the ingot is regulated, there is no mechanism for regulating the outer diameter of the ingot, so it is difficult to maintain the shape of the ingot, especially to keep the outer diameter constant. .

This causes problems such as increased cutting and grinding loss, and problems such as the ingot not being able to fit into the case when manufacturing a tube from the ingot, resulting in a poor yield of ingots.

Therefore, an object of the present invention is to provide a method for manufacturing a cylindrical transparent quartz glass ingot that can improve the yield.

[Means to solve the problem]

In order to solve the above problems, the present invention sprays and deposits fused crystal powder in the form of a mist using a burner on a rotatable fire-resistant head, and detects the upper end position of the fused silica glass deposited. While controlling the flow rate of the gas ejected from the burner so that the deposited thickness remains constant, the cylindrical transparent quartz glass that flows down from the refractory head and solidifies is supported while rotating on a refractory support plate. This is a method of descending at high speed.

[For production]

According to the above means, the amount of molten silica glass flowing down per unit time from above the fireproof head becomes almost constant, and the flow of molten silica glass is evenly carried out in the direction by the rotation of the fireproof support plate. The outer diameter of the transparent quartz glass becomes constant.

Note that carbon is particularly effective as a refractory head, but other ceramic materials may also be used.

Although there are various types of burners to be used, an oxyhydrogen burner in particular can sufficiently bring out the effects of the present invention.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

The figure is a schematic configuration diagram of the manufacturing equipment used to carry out the present invention, in which 1 is a cylindrical fire-resistant head made of carbon and has a hemispherical top; It is rotatably connected to the

The refractory head 1 has quartz crystal powder melted in the form of mist and sprayed together with hydrogen gas as a fuel gas and oxygen gas as a combustion supporting gas or carrier gas by an oxyhydrogen burner 4 placed above the furnace 2. It is deposited by melting.

Below the fireproof head 1, a disk-shaped fireproof support plate 6 having a hole 5 through which the support column 3 can be inserted is provided so as to be rotatable and movable up and down by a rotary lift tube 7.
is rotated and driven up and down at a constant speed by a rotary drive device and a lifting side and device (not shown).

On the other hand, a window 8 is provided in the upper part of the side wall of the furnace 2, and the upper end position of the fused silica glass 9 deposited on the refractory head 1 is detected on the outside of the window 8. 1
A television camera 10 is arranged to measure the deposition thickness ρ of the upper fused silica glass 9.

The production of a cylindrical transparent quartz glass ingot using the apparatus configured as described above involves vertically spraying fused crystal powder in the form of a mist with an oxyhydrogen burner 4 onto the refractory head 1 to melt and deposit it. The upper end position of the quartz glass 9 is detected by the television camera 10, and while controlling the flow rate of the gas ejected from the oxyhydrogen burner 4 so that the deposited thickness g becomes constant, it flows down from the refractory head 1 and solidifies. The cylindrical transparent quartz glass 11 is rotated by the fireproof support plate 6 and lowered at a constant speed.

Example 1 Using a fireproof head 1 with a diameter of 54 mm, a fireproof support plate 6 is mounted, 2r, p, m, ? ? While rotating and descending at a speed of 15 mm/hr (the speed at which the steady section was formed, excluding the initial start-up section and the final finishing section), hydrogen gas was fed as fuel gas from the oxyhydrogen burner 4 at an average rate of 10 mm/hr. 3rIl/hr
.

(min: 10.09ffl/hr, max:
11.25rd/hr, ), oxygen gas as combustion supporting gas average 54nr/hr, (win:5.05nr/hr)
, , max: 5.83nr/hr), while spraying oxygen gas as a carrier gas at 8N/ff1in and crystal powder at an average rate of 0.84kg/hr, a TV camera 10 for position measurement (minimum unit 0.16cm) was used. The upper end position of the fused silica glass 9 was detected, and the deposition thickness g was 85 m+s.
Control the flow rate of gas from the oxy-hydrogen burner 4 so that
A cylindrical transparent quartz glass ingot was manufactured by spending 14 hours on start-up, 31 hours on steady state, and 1 hour on finishing.

The deposited thickness g of the fused silica glass 9 is 63.4 to 69.4 m.
The resulting cylindrical transparent quartz glass ingot weighs 33.0 kg, has an inner diameter of 54 to 60 mm, and an outer diameter of 173.3 to 180.3 mm (steady part only). It was ground to a diameter of 170 mm.

Example 2 Under the same conditions as Example 1, the deposition thickness Ω of fused silica glass 9 was
was varied in the range of 65.0 to 74.6 mm.

About half of the obtained cylindrical transparent quartz glass ingots could not be used due to deterioration in shape such as unevenness, excessively large outer diameter, and bending.

Therefore, it can be seen that the smaller the variation in the deposition thickness p of the fused silica glass 9, the better the ingot shape.

〔Effect of the invention〕

As described above, according to the present invention, the amount of molten silica glass flowing down per unit time from above the fireproof head becomes almost constant, and the flow of molten silica glass is evenly distributed in the direction by the rotation of the fireproof support plate. Since the outer diameter of the cylindrical transparent quartz glass becomes constant, the yield of the ingot can be improved.

[Brief explanation of the drawing]

The figure is a schematic configuration diagram of a manufacturing apparatus used to implement the present invention.

Claims (1)

[Claims] A burner sprays atomized fused quartz powder onto a rotatable fire-resistant head to melt and deposit the fused silica glass, and the top position of the deposited fused silica glass is detected to ensure that the deposited thickness remains constant. A cylindrical structure characterized by a cylindrical transparent quartz glass that flows down from a refractory head and solidifies while being rotated and supported by a refractory support plate and lowered at a constant speed while controlling the flow rate of the gas ejected from the burner. Method for manufacturing transparent quartz glass ingot.