US 11,999,646 B2
Manufacturing method of porous glass base material for optical fiber and manufacturing apparatus
Naoto Noda, Ibaraki (JP); Dai Inoue, Ibaraki (JP); Hitoshi Iinuma, Gunma (JP); and Hiromasa Mizukami, Ibaraki (JP)
Assigned to SHIN-ETSU CHEMICAL CO., LTD., Tokyo (JP)
Appl. No. 17/267,496
Filed by SHIN-ETSU CHEMICAL CO., LTD., Tokyo (JP)
PCT Filed Aug. 2, 2019, PCT No. PCT/JP2019/030486
§ 371(c)(1), (2) Date Feb. 10, 2021,
PCT Pub. No. WO2020/039893, PCT Pub. Date Feb. 27, 2020.
Claims priority of application No. 2018-156708 (JP), filed on Aug. 23, 2018.
Prior Publication US 2021/0292222 A1, Sep. 23, 2021
Int. Cl. C03B 37/018 (2006.01)
CPC C03B 37/01815 (2013.01) [C03B 2207/32 (2013.01); C03B 2207/34 (2013.01); C03B 2207/81 (2013.01); C03B 2207/87 (2013.01); C03B 2207/88 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A manufacturing method of porous glass base material for optical fiber comprising:
pumping a liquid raw material of an organic siloxane stored in a raw material tank at internal pressure P1 into a vaporizer through a pipe at internal pressure P2, controlled by a mass flow controller at a predetermined flow rate;
vaporizing the liquid raw material in the vaporizer and supplying the vaporized raw material to a burner as a gas raw material; and
forming a porous glass base material by depositing silica fine particles formed by burning the gas raw material in the burner,
wherein P1≤P2 is satisfied, and
wherein the manufacturing method further comprises a step of pumping the liquid raw material in the raw material tank to the mass flow controller using a liquid feed pump, wherein
a pressure of the liquid raw material supplied to the mass flow controller is P3, and
in the step of pumping the liquid raw material, the liquid feed pump once pressurizes the pressure of the liquid raw material to P4 and supplies the liquid raw material to the mass flow controller while reducing the pressure to P3 via a pressure loss unit, so that P1≤P2<P3≤0.6 P4 is satisfied.