JPH0127980B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing quartz glass containers.

Conventionally, in order to manufacture a rectangular quartz glass container, as shown in FIG. 1A, a quartz glass main tube 1 is first made from quartz crystal, silica sand, silica stone, etc., and one end 1a of this main tube 1 is sealed. As shown in FIG. 1B, press compressed air from the other end 1b and fit it into the mold 2,
It was formed into a predetermined shape as shown in FIG. 1C, and cut into a container 3 as shown in FIG. 1D.

When manufacturing a rectangular quartz glass container, since the viscosity of quartz glass is high, the wall thickness of the corner portion 3a of the container 3 is thinner than other portions as shown in Fig. 2, and distortion may remain. However, there was a problem that the thermal and mechanical strength decreased.

An object of the present invention is to provide a method for manufacturing rectangular quartz glass containers that have uniform wall thickness, are free from distortion, and do not lack thermal or mechanical strength.

Another object of the present invention is to provide square quartz glass containers at low cost.

The method according to the invention can be applied, for example, to a utility model registration.
It is applied to rotary melting furnaces that use an arc flame or gas flame from the top as a heat source, such as those shown in No. 971264 and Japanese Patent Application Laid-Open No. 54-20014. A core is placed in the center of the rotary melting furnace so that it can be pulled out upwards.

In particular, in the case of a core with a square cross section, it is preferable to instantly reduce the outer diameter of the core so that it can be pulled out. The lower part of the rotary melting furnace and the gap between the core and the furnace wall are filled with quartz glass raw material powder, and while the furnace is rotated, this core is momentarily pulled out as described above, and then the silica glass raw material powder is is heated and melted using an arc flame or gas flame to produce square quartz glass containers.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 3 to 6.

As shown in FIGS. 3 and 4, a core 11 is disposed at the center of the rotary melting furnace 10 so as to be able to be pulled out upward. A gap continuously existing between the lower part 10 of the rotary melting furnace 10 and the core 11 and between the furnace wall 13 of the rotary melting furnace 10 and the core 11 is filled with silica glass raw material powder 14.

Next, as shown in FIGS. 5 and 6, the rotary melting furnace 1
While rotating 0, shrink the core 11 instantly,
Pull upwards. Thereafter, the quartz glass raw material powder thus formed is heated by an arc flame or gas flame (not shown) in the upper part of the furnace.

The rotary melting furnace 10 is rotatable in a predetermined direction about a rotating shaft 15, and is formed into a box shape with a rectangular cross section by a furnace body 16 and a refractory material 17.

The core 11 has a structure that can be instantly reduced. The rotating shaft 18 of the core 11 is coaxial with the rotating shaft 15 on the rotary melting furnace 10 side, so that they can rotate synchronously and can be pulled upward as necessary. There is.

For example, a pair of bushes 19 on the rotating shaft 18,
20 are slidably arranged, and links 22 are respectively pivotally supported on these bushes 19 and 20 and on a support section 21 at the top. These links 2
A thick cloth 23 is pasted on the outside of 2. By moving the upper bush 19, it can be instantly transformed into the expanded state shown in FIGS. 3 and 4 and the contracted state shown in FIGS. 5 and 6.

To explain the operation of the example shown in FIGS. 3 to 6, after setting the rectangular core 11 in the furnace 10, the quartz glass raw material powder 14 is filled in the furnace 10, and the furnace 10 and the core 11 are After rotating on the same axis and reaching a rotation speed that allows molding, the bush 19 is moved upward to momentarily shrink the core 11 and then pulled out.
The quartz glass raw material powder 14 is melted from above using an arc flame or a gas flame (not shown).

The number of rotations when the core 11 is pulled out varies depending on the size of the rectangular quartz glass container to be manufactured and the particle size of the raw material. For example, if the rotation speed is high, the molded product will not be able to maintain its square shape due to centrifugal force and will become round, and if it is low, the molded product will collapse, so care must be taken.

Note that the core 11 is not of the link type as shown in the illustrated example, but may also be of a fluid pressure type.

The rectangular quartz glass container manufactured according to the present invention requires fewer and shorter manufacturing steps than the conventional method, making it possible to significantly reduce costs.

Further, by the manufacturing method of the present invention, the square quartz glass container has a uniform wall thickness, almost no distortion remains, and the thermal and mechanical strength does not decrease.

Using the device shown in Figures 3 to 6, fill with crystal powder of sizes 30 to 60, rotate the device at 110 rpm, pull out the core 11 upwards, and then blow arc flame from the arc electrode from above. By melting crystal powder, the external dimensions are 300mm x 120mm and the wall thickness is 12mm.
A square quartz glass container was manufactured.

When this rectangular quartz glass container was used for firing fluorescent paint at 1070°C, conventionally it could only be used 20 to 30 times due to cracks caused by thermal shock.
The method according to the present invention can be used 30 to 60 times.

[Brief explanation of drawings]

Figures 1A to D are explanatory diagrams showing the manufacturing process of a conventional square quartz glass container, Figure 2 is a vertical cross-sectional view showing an example of a square quartz glass container manufactured by the conventional method, and Figures 3 to 6. 3 and 4 are schematic cross-sectional views showing an apparatus for carrying out the method of the present invention, in which FIGS. 3 and 4 show the core in an enlarged state, and FIGS. 5 and 6 show the core in a contracted state. DESCRIPTION OF SYMBOLS 1... Quartz glass main tube, 2... Mold, 3... Container, 10... Rotary melting furnace, 11... Core, 15...
...rotation axis, 18...rotation axis.

Claims (1)

[Claims] 1. In a rotary melting furnace that uses an arc flame or gas flame from above as a heat source, a core having a structure that can be instantly shrunk is disposed in the center of the rotary melting furnace so that it can be pulled upward, and The lower part of the melting furnace and the gap between the core and the furnace wall are filled with quartz glass raw material powder, and while the rotary melting furnace is rotated, the outer shape of the core is instantly reduced and pulled upward, and then the quartz glass raw material is A method for producing quartz glass containers, which comprises heating powder with an arc flame or gas flame. 2. The method for manufacturing quartz glass containers according to claim 1, wherein the core has a rectangular horizontal cross section.