Abstract: In a method of manufacturing porous glass base for optical fiber, a liquid organic siloxane raw material stored in a raw material tank of internal pressure P1 is controlled by a mass flow controller at a predetermined flow rate and pumped through pipe of internal pressure P2 to a vaporizer, the liquid raw material is vaporized in the vaporizer and supplied as a gas raw material to a burner, and the silica fine particles formed by burning the gas raw material in the burner are deposited to form a porous glass base material, where P1?P2 is satisfied.

Abstract: A porous glass base material manufacturing apparatus for an optical fiber includes: a liquid mass flow controller for controlling a flow rate of raw material liquid of an organic siloxane; a vaporizer for mixing raw material liquid and carrier gas to vaporize raw material liquid to form mixed gas; a raw material liquid nozzle for ejecting raw material liquid into the vaporizer; a carrier gas supply pipe for supplying carrier gas into the vaporizer; a raw material liquid pipe for introducing raw material liquid into the nozzle; a burner for combusting mixed gas with combustible gas and combustion supporting gas to produce SiO2 particles; a mixed gas pipe for supplying mixed gas to the burner; an open/close valve on a flow path of the raw material liquid pipe; and a purge gas supply pipe that joins the raw material liquid pipe between the valve and the raw material liquid nozzle.

Abstract: A manufacturing method of a porous glass base material for optical fiber includes: controlling a flow rate of a raw material liquid of an organic siloxane by a liquid mass flow controller; introducing raw material liquid to a raw material liquid nozzle of a vaporizer by a raw material liquid pipe; ejecting raw material liquid into the vaporizer; mixing raw material liquid and carrier gas to vaporize raw material liquid to form mixed gas; supplying mixed gas to a burner; combusting mixed gas together with a combustible gas and a combustion supporting gas in the burner to produce SiO2 particles; depositing SiO2 particles on a starting core base material to form the porous glass base material; and closing an open/close valve on a flow path of the raw material liquid pipe to stop supply of raw material liquid, while continuing to supply carrier gas, combustible gas, and combustion supporting gas.

Abstract: A porous glass base material manufacturing apparatus for an optical fiber includes: a liquid mass flow controller for controlling a flow rate of raw material liquid of an organic siloxane; a vaporizer for mixing raw material liquid and carrier gas to vaporize raw material liquid to form mixed gas; a raw material liquid nozzle for ejecting raw material liquid into the vaporizer; a carrier gas supply pipe for supplying carrier gas into the vaporizer; a raw material liquid pipe for introducing raw material liquid into the nozzle; a burner for combusting mixed gas with combustible gas and combustion supporting gas to produce SiO2 particles; a mixed gas pipe for supplying mixed gas to the burner; an open/close valve on a flow path of the raw material liquid pipe; and a purge gas supply pipe that joins the raw material liquid pipe between the valve and the raw material liquid nozzle.

Abstract: A manufacturing apparatus of a porous glass base material for optical fiber includes: a liquid mass flow controller for controlling a flow rate of a raw material liquid of an organic siloxane; a vaporizer for mixing the raw material liquid and a carrier gas to vaporize the raw material liquid to form a mixed gas in which a raw material gas and the carrier gas are mixed; a raw material liquid nozzle for ejecting the raw material liquid into the vaporizer; a carrier gas supply pipe for supplying the carrier gas into the vaporizer; a raw material liquid pipe for introducing the raw material liquid into the raw material liquid nozzle; a burner for combusting the mixed gas together with a combustible gas and a combustion supporting gas to produce SiO2 fine particles; a mixed gas pipe; an open/close valve; and a purge gas supply pipe.

Abstract: A manufacturing method of a porous glass preform for optical fiber by depositing glass microparticles on a starting member, including supplying a vaporizer with organic silicon compound raw material in a liquid state and a carrier gas; in the vaporizer, mixing and vaporizing the organic silicon compound raw material in a liquid state and the carrier gas to convert the organic silicon compound raw material and the carrier gas into a raw material mixed gas; supplying a burner with the raw material mixed gas and a combustible gas, combusting the raw material mixed gas and the combustible gas in the burner, and ejecting SiO2 microparticles generated by the combustion from the burner; and depositing the SiO2 microparticles ejected from the burner on the starting member by repeatedly moving a single body, in which the vaporizer and the burner are synchronized, parallel to the starting member in a longitudinal direction thereof.

Abstract: A manufacturing method of a porous glass preform for optical fiber by depositing glass microparticles on a starting member, including supplying a vaporizer with organic silicon compound raw material in a liquid state and a carrier gas; in the vaporizer, mixing and vaporizing the organic silicon compound raw material in a liquid state and the carrier gas to convert the organic silicon compound raw material and the carrier gas into a raw material mixed gas; supplying a burner with the raw material mixed gas and a combustible gas, combusting the raw material mixed gas and the combustible gas in the burner, and ejecting SiO2 microparticles generated by the combustion from the burner; and depositing the SiO2 microparticles ejected from the burner on the starting member by repeatedly moving the vaporizer and the burner together, in a synchronized manner, parallel to the starting member in a longitudinal direction thereof.

Abstract: A flow rate fluctuation of the liquid raw material of the organic siloxane supplied to the vaporizer is suppressed and a deposition density of the silica fine particles is uniformizes. The method of manufacturing the porous glass base material according to the present invention, a liquid organic siloxane raw material stored in a raw material tank of internal pressure P1 is controlled by a mass flow controller at a predetermined flow rate and pumped through pipe of internal pressure P2 to a vaporizer, the liquid raw material is vaporized in the vaporizer and supplied as a gas raw material to a burner, and the silica fine particles formed by burning the gas raw material in the burner are deposited to form a porous glass base material. The present invention is characterized by the method of manufacture described above, wherein P1?P2 is satisfied.

Abstract: A manufacturing apparatus of a porous glass base material for optical fiber includes: a liquid mass flow controller for controlling a flow rate of a raw material liquid of an organic siloxane; a vaporizer for mixing the raw material liquid and a carrier gas to vaporize the raw material liquid to form a mixed gas in which a raw material gas and the carrier gas are mixed; a raw material liquid nozzle for ejecting the raw material liquid into the vaporizer; a carrier gas supply pipe for supplying the carrier gas into the vaporizer; a raw material liquid pipe for introducing the raw material liquid into the raw material liquid nozzle; a burner for combusting the mixed gas together with a combustible gas and a combustion supporting gas to produce SiO2 fine particles; a mixed gas pipe; an open/close valve; and a purge gas supply pipe.

Abstract: A manufacturing method of a porous glass preform for optical fiber by depositing glass microparticles on a starting member, including supplying a vaporizer with organic silicon compound raw material in a liquid state and a carrier gas; in the vaporizer, mixing and vaporizing the organic silicon compound raw material in a liquid state and the carrier gas to convert the organic silicon compound raw material and the carrier gas into a raw material mixed gas; supplying a burner with the raw material mixed gas and a combustible gas, combusting the raw material mixed gas and the combustible gas in the burner, and ejecting SiO2 microparticles generated by the combustion from the burner; and depositing the SiO2 microparticles ejected from the burner on the starting member by repeatedly moving the vaporizer and the burner together, in a synchronized manner, parallel to the starting member in a longitudinal direction thereof.

Abstract: An improvement is proposed in the method for the flame hydrolysis of a silicon-containing gas, e.g., silicon tetrachloride, to produce fine silica particles to be deposited on a substrate in a process for the preparation of a silica glass preform of optical fibers by using a fivefold concentric multiplex-tube burner nozzle. In contrast to the conventional way for the flame hydrolysis in which the center or first nozzle opening of the burner serves for ejection of a mixture of silicon tetrachloride and oxygen and hydrogen is ejected from the third nozzle opening while argon is ejected from the second nozzle opening inbetween, the gas ejected from the second nozzle opening is, instead of argon alone, a mixture of oxygen and argon in a specified mixing proportion so that deposition of silica particles on the nozzle end can be prevented even when the feed rate of silicon tetrachloride is relatively high.