Quartz glass manufacturing method and quartz glass manufacturing apparatus

Abstract

Provided is a quartz glass manufacturing method that involves using one or more burners, supplying hydrogen and oxygen to the one or more burners to generate an oxyhydrogen flame, introducing a silicide into the oxyhydrogen flame, forming a porous base material by depositing silicon dioxide generated from a flame hydrolysis reaction with the silicide, and heating and sintering the porous base material to form transparent glass, the method comprising supplying hydrogen that is stored or made at a normal temperature to the one or more burners; controlling a hydrogen flow rate using a measurement apparatus or control apparatus that performs measurement based on heat capacity of a gas; vaporizing liquid hydrogen stored in a low-temperature storage chamber, and supplying the vaporized liquid hydrogen to the one or more burners as backup hydrogen; switching from the hydrogen to the backup hydrogen; and when switching, adjusting the hydrogen flow rate to a value obtained by multiplying the hydrogen flow rate immediately after switching by a predetermined correction coefficient.

1 . A quartz glass manufacturing method that involves using one or more burners, supplying hydrogen and oxygen to the one or more burners to generate an oxyhydrogen flame, introducing a silicide into the oxyhydrogen flame, forming a porous base material by depositing silicon dioxide generated from a flame hydrolysis reaction with the silicide, and heating and sintering the porous base material to form transparent glass, the quartz glass manufacturing method comprising:
 supplying hydrogen that is stored or made at a normal temperature to the one or more burners;   controlling a hydrogen flow rate using a measurement apparatus or control apparatus that performs measurement based on heat capacity of a gas;   vaporizing liquid hydrogen stored in a low-temperature storage chamber, and supplying the vaporized liquid hydrogen to the one or more burners as backup hydrogen;   switching from the hydrogen to the backup hydrogen; and   when switching, adjusting the hydrogen flow rate to a value obtained by multiplying the hydrogen flow rate immediately after switching by a predetermined correction coefficient.   
   
   
       2 . The quartz glass manufacturing method according to  claim 1 , wherein
 the measurement apparatus or control apparatus that performs measurement based on heat capacity of a gas is a mass flow controller.   
   
   
       3 . The quartz glass manufacturing method according to  claim 1 , wherein
 the silicide is silicon tetrachloride.   
   
   
       4 . The quartz glass manufacturing method according to  claim 1 , wherein
 a germanium compound is added to the silicide supplied to the flame of at least one burner from among the one or more burners.   
   
   
       5 . The quartz glass manufacturing method according to  claim 4 , wherein
 the germanium compound is germanium tetrachloride.   
   
   
       6 . The quartz glass manufacturing method according to  claim 1 , wherein
 the porous base material is formed by sequentially depositing on a tip of a starting material being lifted and rotated according to a VAD technique.   
   
   
       7 . The quartz glass manufacturing method according to  claim 1 , wherein
 the porous base material is formed by depositing around a starting material being rotated according to an OVD technique.   
   
   
       8 . A quartz glass manufacturing apparatus that uses one or more burners, supplies hydrogen and oxygen to the one or more burners to generate a oxyhydrogen flame, introduces a silicide into the oxyhydrogen flame, forms a porous base material by depositing silicon dioxide generated from a flame hydrolysis reaction with the silicide, and heats and sintering the porous base material to form transparent glass, the quartz glass manufacturing apparatus comprising:
 first hydrogen supply equipment that supplies hydrogen that is stored or made at a normal temperature to the one or more burners;   second hydrogen supply equipment that includes at least a low-temperature storage chamber and a vaporizer, and that uses the vaporizer to vaporize liquid hydrogen stored in the low-temperature storage chamber to generate and supply backup hydrogen as a backup for the hydrogen that is stored or made at the normal temperature;   a measurement apparatus or control apparatus that performs measurement based on heat capacity of a gas to control a hydrogen flow rate; and   a correction apparatus that, when the switching to the backup hydrogen occurs, adjusts a set value of the hydrogen flow rate to a value obtained by multiplying the hydrogen flow rate immediately after switching by a predetermined correction coefficient.   
   
   
       9 . The quartz glass manufacturing apparatus according to  claim 8 , wherein
 the measurement apparatus or control apparatus that performs measurement based on heat capacity of a gas is a mass flow controller.   
   
   
       10 . The quartz glass manufacturing apparatus according to  claim 8 , further comprising a detecting section that detects switching of a hydrogen supply source from a first hydrogen supply apparatus to a second hydrogen supply apparatus, wherein
 the correction apparatus includes:
 a correction coefficient storage section that stores the correction coefficient; and 
 a calculating section that multiplies the correction coefficient by a set value of the hydrogen flow rate when the detecting section has detected that the hydrogen supply source has switched from the first hydrogen supply apparatus to the second hydrogen supply apparatus. 
   
   
   
       11 . The quartz glass manufacturing apparatus according to  claim 8 , wherein
 the correction coefficient is a value that increases the hydrogen flow rate by approximately 1%.   
   
   
       12 . The quartz glass manufacturing method according to  claim 1 , wherein
 the correction coefficient is a value that increases the hydrogen flow rate by approximately 1%.