Method for producing synthetic quartz glass

Patent metadata

Field	Value
Publication number	US-9481597-B2
Application number	US-201214365944-A
Country	US
Kind code	B2
Filing date	Dec 13, 2012
Priority date	Dec 16, 2011
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

The invention relates to a method for producing synthetic quartz glass by vaporizing a polyalkylsiloxane as a liquid SiO 2 feedstock ( 105 ), converting the vaporized SiO 2 feedstock ( 107 ) into SiO 2 particles, separating the SiO 2 particles, forming a soot body ( 200 ) and vitrifying the soot body ( 200 ). According to the invention, the vaporizing of the heated SiO 2 feedstock ( 105 ) comprises an injection phase in an expansion chamber ( 125 ), in which the SiO 2 feedstock ( 105 ) is atomized into fine droplets, wherein the droplets have an average diameter of less than 5 pm, and wherein the atomizing of the droplets takes place in a preheated carrier gas stream which has a temperature of more than 180° C.

First claim

The invention claimed is:

1. A method for producing synthetic quartz glass, said method comprising:
(A) providing a liquid SiO 2 feedstock having more than 70% by wt. of octamethylcyclotetrasiloxane,
(B) vaporizing the liquid SiO 2 feedstock into a gaseous SiO 2 feedstock vapor,
(C) converting the SiO 2 feedstock vapor into SiO 2 particles,
(D) depositing the SiO 2 particles on a deposition surface so as to form a SiO 2 soot body,
(E) vitrifying the SiO 2 soot body so as to form the synthetic quartz glass,
wherein the vaporizing of the SiO 2 feedstock comprises injection of the liquid SiO 2 feedstock into an expansion chamber such that the SiO 2 feedstock is atomized into fine droplets, wherein the droplets have a mean diameter of less than 5 μm, and
wherein the droplets are atomized in a preheated carrier gas stream that has a temperature of more than 180° C. and wherein a molar ratio of carrier gas to siloxane is greater than or equal to 1.5.

2. The method according to claim 1 , wherein the droplets have a mean diameter of less than 2 μm and wherein the carrier gas stream is supplied at a pressure of 1.5 to 5 bar.

Assignees

• Heraeus Quarzglas

Inventors

• Badeke Klaus-Uwe
• Otto Norbert
• Trommer Martin
• Laudahn Hilmar
• Brueckel Andreas

Classifications

• Y02P40/57

  Improving the yield, e-g- reduction of reject rates · CPC title

• C03B2201/02

  Pure silica glass, e.g. pure fused quartz · CPC title

• C03B2207/32

  Non-halide · CPC title

• C03B2207/85

  with vapour generated from liquid glass precursors, e.g. directly by heating the liquid · CPC title

• C03B19/1415 Primary

  Reactant delivery systems · CPC title