Patent ID: 8650912

Claim:
A method for the manufacture of a synthetic quartz glass ingot using a burner comprising a main burner comprising a multi-tube assembly of a three or more tube construction including a center tube, a first enclosure tube surrounding the center tube, and a second enclosure tube surrounding the first enclosure tube, a tubular shell surrounding the multi-tube assembly, and a plurality of nozzles disposed within the tubular shell, the main burner defining a forward opening, and a double-tube assembly surrounding at least the forward opening of the main burner; said method comprising the steps of: placing the burner to face a quartz glass target mounted on a rotating support, feeding a silica-forming compound to the center tube, a combustion-supporting gas to the first enclosure tube and the nozzles, a combustible gas to the second enclosure tube and the tubular shell, and a combustion-supporting gas to the double-tube assembly, wherein the combustible gas fed through the tubular shell is channeled to flow about the nozzles, forming an oxyhydrogen flame from the combustion-supporting gas and the combustible gas for subjecting the silica-forming compound to vapor phase hydrolysis or oxidative decomposition to form silica fines, depositing the silica fines on the target, and simultaneously melting and vitrifying the deposited silica into quartz glass; wherein the silica-forming compound is fed to the center tube at a flow rate of 0.3 to 0.7 Nm 3 /hr, combustion-supporting gas is additionally fed to the center tube at a flow rate of 2.0 to 4.0 Nm 3 /hr, the flow rate of combustion-supporting gas through the first enclosure tube is 0.3 to 2.5 Nm 3 /hr the flow rate of combustible gas through the second enclosure tube is 12 to 15 Nm 3 /hr, the flow rate of combustible gas through the shell is 20 to 25 Nm 3 /hr, the total flow rate of combustion-supporting gas through the nozzles is 10 to 16 Nm 3 /hr, and the flow rate of combustion-supporting gas through the double-tube assembly is 2 to 5 Nm 3 /hr.