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Quartz glass made burner

Quartz glass made burner description/claims

This is a continuation application of PCT/JP2007/053841 filed on Feb. 28, 2007 which claims priority from a Japanese Patent Application NO. 2006-053215 filed on Feb. 28, 2006, the contents of which are incorporated herein by reference.

1. Technical Field

The present invention relates to a quartz glass burner. In particular, the present invention relates to a quartz glass burner suitable for use in flame working, manufacturing of synthetic quartz glass, and the like.

2. Background Art

A quartz glass burner can achieve high temperatures by feeding a supporting gas from an inner tube nozzle into an outer tube containing a combustible gas to ignite the combustible gas, and is therefore used for various types of flame working. When using a burner in which a plurality of tubules serving as nozzles are inserted throughout the outer tube, in addition to feeding a supporting gas from an inner tube nozzle into an outer tube containing a combustible gas to ignite the combustible gas, a gas containing pieces of glass is fed through any of the tubules to achieve flame hydrolysis, thereby synthesizing the quartz glass microparticles.

FIG. 4 shows a conventional quartz glass burner. In FIG. 4, the quartz glass burner is provided with a quartz glass outer tube, a tubule branching portion, and a multibranched-tube quartz glass nozzle that is positioned on an inner side of an outer tube and that houses a plurality of tubules formed continuously along the tubule branching portion.

Conventionally, the positioning and number of nozzles feeding the supporting gas in this type of quartz glass burner is considered in an attempt to enhance the firepower during flame working and increase the glass microparticle deposition efficiency.

For example, Patent Document 1 designates the positioning and number of nozzles in order to enhance the glass microparticle synthesizing efficiency and deposition efficiency. In Patent Document 2, the diameter and speed of the nozzle is designated.

However, optimizing the supply of gas from the nozzles is not the only way to enhance the flame working efficiency and the deposition efficiency. It is also important to optimize the supply of gas from the outer tube. A flow velocity distribution often occurs in the supply of gas from the outer tube due to the large area through which the gas flows, such that the flow velocity at the tip of the burner is uneven. This causes a temperature irregularity, which decreases the flame working efficiency and the deposition efficiency. This temperature irregularity is especially prominent when enlarging the diameter of the outer tube to enlarge the flame.

Patent Document 1: Japanese Patent Application Publication No. 2003-206154

Patent Document 2: Japanese Patent Application Publication No. 2003-165737

It is an object of an aspect of the innovations herein to provide a quartz glass burner that enhances the firepower during flame working and increases the glass microparticle deposition efficiency by causing the flow velocity distribution of the gas supplied from the outer tube to be uniform at the tip of the burner. The above and other objects can be achieved by combinations described in the independent claims. The dependent claims define further advantageous and exemplary combinations of the innovations herein.

According to a first aspect related to the innovations herein, one exemplary quartz glass burner may include a quartz glass burner including a multibranched-tube quartz glass nozzle made up of multiple tubules housed in a quartz glass outer tube, wherein an inner diameter of the outer tube contracted such that an inner diameter of a tip of the outer tube is between 0.65 and 0.90 times the inner diameter of a trunk of the outer tube.

It is desirable that the nozzle is structured such that a region from a tubule branching portion to a tip of the nozzle is housed in the outer tube, and that the outer tube housing the tubules has a length that is greater than or equal to 1.5 times the inner diameter of the tip of the outer tube.

The summary clause does not necessarily describe all necessary features of the embodiments of the present invention. The present invention may also be a sub-combination of the features described above.

FIG. 1 is a schematic cross-sectional view taken along a vertical axis of the burner showing an exemplary quartz glass burner of the present invention.

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• Utility Patent

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