Manufacturing apparatus and manufacturing method of porous glass base material for optical fiber

A manufacturing method of a porous glass base material for optical fiber comprising:

• controlling a flow rate of a raw material liquid of an organic siloxane by a liquid mass flow controller;
• introducing the raw material liquid supplied from the liquid mass flow controller to a raw material liquid nozzle of a vaporizer by a raw material liquid pipe;
• ejecting the raw material liquid from the raw material liquid nozzle into the vaporizer;
• mixing the raw material liquid ejected in the vaporizer and a carrier gas to vaporize the raw material liquid to form a mixed gas in which the raw material gas and the carrier gas are mixed;
• supplying the mixed gas to a burner;
• combusting the 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 for optical fiber;
• closing an open/close valve provided on a flow path of the raw material liquid pipe to stop the supply of the raw material liquid from the liquid mass flow controller;
• and
• supplying a purge gas from a purge gas supply pipe that joins the raw material liquid pipe between the open/close valve and the raw material liquid nozzle to the raw material liquid pipe.