JPS6360116A - Production of quartz-base pipe - Google Patents

Abstract

PURPOSE:To easily draw out a specified composite mandrel and to produce a finished quartz-base pipe with high precision without dispersion of inner diameter by transparently vitrifying a porous glass layer formed on the outer periphery of the specified composite mandrel and thereafter drawing out the mandrel from the axial center. CONSTITUTION:A composite mandrel 24 is made by incompletely burning i.e. C6H6, depositing and forming a carbon layer 22 on the outer periphery of a core material 21 made of ceramic such as ZrO2. Then SiCl2 is gasified and completely burned to produce sooty fine glass particles and these are deposited to the outside of the composite mandrel 24 and thereafter transparently vitrified by heating them at high temp. in the atmosphere contg. i.e. He. A quartz pipe 25 is produced by drawing out the composite mandrel 24 from the axial center of the transparent glass layer. The drawing of the composite mandrel 24 is facilitated because the function of a mold release agent is imparted by the carbon layer 22. Further even if roughness is caused on the outer peripheral surface of the mandrel 24 in case of the drawing, it can be repeatedly used by grinding and removing the carbon layer 22 remaining on the outer periphery of the core material 21 and forming the fresh carbon layer 22.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application 1 The present invention relates to a method for manufacturing RI-English pipes used in communications and optics.

1. Prior Art J Quartz-based pipes used as materials for optical fibers, rod lenses, etc. are manufactured, for example, by the OVD method.

As is well known, in the OVD method, soot-like glass particles generated by flame hydrolysis or the like are deposited on the outer periphery of a mandrel to form a porous glass layer, and after the porous glass layer is turned into transparent glass by heat treatment, After pulling out the mandrel from the axis of the transparent glass layer or pulling out the mandrel from the axis of the porous glass layer, the porous glass layer is heat-treated to turn it into transparent glass.

In general, it is said that a mandrel that has weak adhesion to soot, glass, etc., and a material that has a large difference in thermal expansion coefficient is good, and this improves the stripping characteristics during the 1-Lk drawing.

Specifically, mandrels made of carbon are already in use, and mandrels made of ceramics such as Al2O2, Zr0z, MgO, etc. are also used.

``Problems to be solved by the invention'' In the case of the above-mentioned carbon pundrel,
However, since the - part of the mandrel adheres to the inner circumferential surface of the transparent glass layer (pipe) or is oxidized by the heat treatment during transparent glass formation, the mandrel surface (outer circumferential surface) will be eight.

Therefore, when reusing the mandrel, it is necessary to polish the outer circumferential surface of the mandrel, but as this process is repeated, the mandrel becomes thinner than the limit, and the inner diameter of the quartz-based bulb becomes thinner. Variations occur.

・In the case of a mandrel made of a ceramic iron, it is desirable because it has a large coefficient of thermal expansion, but since it has a high degree of adhesion to the transparent glass layer (pipe), it is quite difficult to pull out the mandrel.

In view of the problem described in item 1-1, the present invention is intended to provide a method for manufacturing a quartz pipe in which the mandrel and the transparent glass layer (pipe) can be easily separated.

The method for producing a quartz-based pipe according to the present invention involves forming a composite mandrel by depositing a carbon layer on the outer periphery of a ceramic core, and then forming a composite mandrel. A quartz-based porous glass layer is deposited on the outer periphery of the mandrel, and after the porous glass layer is made into transparent glass, the axial center of the transparent glass layer is
The feature is that the composite mandrel is pulled out.

1 Effect 1 1- In the method of the present invention described above, a composite mandrel is produced by depositing a carbon layer on the outer periphery of a ceramic core material.

In the case of such a mandrel, the core material is a ceramic having a large coefficient of thermal expansion, and the carbon layer around the core has a low adhesion to glass.

In other words, as a mandrel, it should satisfy its 21# characteristics, 4t'J! It is fully equipped.

Therefore, after depositing a porous glass layer around the outer periphery of the mandrel and converting the porous glass layer into transparent glass, it is possible to pull out the mandrel from the axis of the transparent glass layer (pipe) very smoothly. Ru.

In addition, since the carbon layer on the outer periphery of the mandrel only functions as a so-called mold release agent, it is sufficient to form it very thinly, and during the above-mentioned hollowing out, the carbon layer is attached to the inner peripheral surface of the transparent glass layer (pipe). Even if the carbon layer that remains on the outer surface of the mandrel becomes rough due to adhesion, if the carbon layer remaining on the outer surface of the core material is removed by polishing and a new carbon layer is formed, repeated use of the ceramic core material can be reduced. becomes.

Furthermore, the ceramic core material ensures basic dimensions, and the carbon layer ensures minute dimensional accuracy, making it possible to finish the pipe with high viscosity without variation in the inner diameter.

Embodiment Example 1 Hereinafter, one embodiment of the method of the present invention will be explained with reference to the drawings.
IJ.

In FIG. 1, la and lb are chucks installed in a known OVD lathe, 2a and 2b are: JAi'sJ support 3 is a burner with a multi-tube structure, 4.5 is a bubbling tank, 6.7. 8 is a gas pump, 9 is a bubbling tank 4.5
a piping system connecting the gas pump 6 and the gas pump 6; 10. ii
is a mass flow controller installed in the piping system 9,
12 is a piping system connecting the burner 3 and the bubbling tank 4.5, and 13.14 is a piping system connecting the gas pump 7.8 and the burner 3.

In addition, silicon tetralljide (liquid phase) is contained in the bubbling tank 4.
The bubbling tank 5 contains liquid phase benzene (Cb Hb ).

Further, the gas pump 6 contains argon, the gas pump 7 contains oxygen, and the gas pump 8 contains hydrogen.

In FIG. 1, when carrying out the method of the present invention, Al2O3
, 2rO2, MgO, etc., are fitted with sabots 2a and 2b at both ends, and the core material 21 is set in chucks la and lb via these sabots 2a and 2b.

1- On the outer periphery of the core material 21, as shown in FIG. 2, a carbon layer 22 and a quartz-based porous glass layer 23 are deposited.
2. Form a porous glass layer 23.

Initially, when forming the carbon layer 22 on the outer periphery of the core material 21, argon is blown into the entire bubbling tank 5 of the gas pump 6 through the piping system 9, and thereby vaporized CBN6 is supplied from the piping system 12 to the eighth 3. At the same time, oxygen from gas pump 7.8 and rice are transferred to burner 3 from piping system 13.14.
supply to

Burner 3, which is supplied with gas as described above, brings it into a combustion state and generates carbon by incompletely burning CbHh, but the carbon thus generated is
It is injected from the tip of the burner 3 that reciprocates along the longitudinal direction of the outer periphery of the core material 21 and is deposited on the outer periphery of the core material 21 which is in a rotating state.

A carbon layer 22 is thus formed on the outer periphery of the core material 21, and a composite mandrel 24 made of the core material 21 and the carbon layer 22 is obtained.

Next, when forming the porous glass layer 23 on the outer periphery of the carbon layer 22, the hydrogen supply Y to the burner 3 is left unchanged, the amount of oxygen supplied is increased, and the bubbling tank 5 is replaced with bubbling Itl! After 4n is connected to burner 3, argon from gas pump B is blown into bubbling tank 5 to supply vaporized Sic 14 to 7<-s3, which is completely combusted to form soot-like glass. Generate @particle-.

The glass v & particles thus generated are also as described above.
/S-3 is injected from the tip and deposited on the outer periphery of the carbon layer 22, thereby forming a porous glass layer 23 on the outer periphery of the carbon layer 22.

Thereafter, the porous glass layer 23 is heated to a high temperature in an electric furnace maintained in a helium-containing atmosphere or a fluorine-containing gas atmosphere, thereby becoming transparent vitrified to become a transparent glass layer.

After transparent vitrification, the composite mandrel 24 is pulled out from the axis of the transparent glass layer to obtain a desired quartz pipe 25 as shown in FIG.

Next, 14 examples of uninvented methods and comparative examples thereof will be explained.

Specific Example 1 As the ceramic core material 21, a ZrO,+ tube with an inner diameter of 25.0 viφ, an outer diameter of 29.9 viφ, and a length of 400++n was used.

When depositing and forming the carbon layer 22 on the outer periphery of the core material 21, 500 sQ/
By blowing in ^' of Kokuin, the benzene vaporized by this and H2 of 51/win were supplied into the burner 3, and these were incompletely combusted to generate carbon.

When the carbon thus produced was injected and deposited on the outer periphery of the core material 21 from the burner 3, the reciprocating speed of the eights 3 was 80 mm/set n, and the number of deposited carbon layers was five.

After forming the carbon layer 22 as described above, the burner 3 is immediately filled with 5 sentences/! The burner 3 is supplied with Ar of 220 so/win to increase its firepower.
5 vaporized by blowing /S into the bling tank 5.
iCI4 was supplied, thereby producing 5i02Wi particles.

Does it take Sio? Forty layers of fine particles were deposited on the outer periphery of the carbon layer 22 in the same manner as described above, thereby forming a porous glass layer 23.

Thereafter, the porous glass layer 23 is placed in a He atmosphere at 1550° C. to make it transparent and vitrified, and a nodrel 24 is pulled out from the axis of the transparent glass layer using a composite material. 33.0 ■ Small, length 3
A quartz-based pipe 25 with a diameter of 0.00 mm was obtained.

This quartz pipe 25 can be used in the first shift without bending.
I was there.

In addition, the composite mandrel 24 could be reused by removing the carbon layer 22 on its outer peripheral surface and lightly polishing it.

Comparative Example 1 Zr0;
As a result, the Zr02 tube core material 21 and the transparent glass layer were welded together, and cracks were generated on the transparent glass layer.

Comparative Example 2 The core material 21 had an inner diameter of 26.0 layers φ, an outer diameter of 30.0 viφ,
A porous glass layer 23 was deposited on the outer periphery of the core under the same conditions as in Example 1, except that a quartz tube with a length of 400 mm was used, and this was made into transparent glass.

In the case of Comparative Example 2, no cracks occurred in the transparent glass layer, but the mandrel could not be pulled out from the axis of the transparent glass layer.

Specific example 3 When the porous glass layer 23 formed in the same manner as in specific example 1 is made into transparent vitrification, the transparent vitrification atmosphere is )Ie
+F2 +SOr “02, Δ= −0,
2$ (7) A fluorine-doped quartz pipe was obtained.

This quartz pipe 25 is also straight with no bends.
- Shi, the mandrel 24 was also reused.

IL body example 4 When forming the porous glass layer 23 in the same manner as in specific example 1, 5iGln was used as a vapor phase glass raw material in the burner 3.
and BCla as the dope raw material in the gas phase.
After this formed a porous glass layer 23 containing B2O3, the porous glass layer 23 was made into transparent glass in the same manner as in Example 1.

As a result, a poron-doped quartz pipe was obtained, but this quartz pipe 25 was also free from bending, and the mandrel 24 could also be reused.

γ Effect of invention, l 1- As explained, according to the method of the present invention,! teeth.

A quartz-based porous glass layer is deposited on the outer periphery of a composite mandrel consisting of a ceramic core material and a carbon layer on its outer periphery, and after converting the porous glass layer into Transparent No. 1 vitrification, the transparent glass layer is Since the mandrel is pulled out from the axis of the mandrel, repeated use of the mandrel is prohibited (
The inner diameter accuracy of the quartz pipe to be folded can also be ensured.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram schematically showing an example of the 11 unreleased methods;
FIG. 2 is a cross-sectional view showing the stacked state of the carbon layer and porous glass layer in the method of the present invention, and FIG. 3 is a perspective view of a quartz-based bulb manufactured by unexploited IIh blasting. la, lbΦ...Chuck 3 of Sawa 3 for OVD ee
Φ1111 Burner 4.5--Bubbling tank 22IllI@...Carbon layer 23 and--Porous glass layer 24--Composite mandrel 25...Quartz-based pipe representative JR Physician Kato Yoshio Figure 1 Figure 12

Claims (3)

[Claims] (1) A composite mandrel is created by depositing a carbon layer on the outer periphery of a ceramic core material, and then a quartz-based porous glass layer is deposited on the outer periphery of the composite mandrel,
A method for manufacturing a quartz pipe, which comprises turning the porous glass layer into transparent glass, and then pulling out the composite mandrel from the axis of the transparent glass layer. (2) The method for manufacturing a quartz pipe according to claim 1, wherein the ceramic core material has a pipe shape. (3) Ceramic core material is Al_2O_3, ZrO_
2. Claim 1 or 2 consisting of MgO etc.
A method for manufacturing a quartz-based pipe as described in Section 1.