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US 10,472,270 B2Granted
Porous glass base material sintering method and sintering apparatus
AssigneeShin-Etsu Chemical Co., Ltd.
InventorTetsuya Otosaka
Life of this patent
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Abstract
A porous glass base material sintering method comprising measuring a feeding speed Vf of a porous glass base material and a movement speed Vw of a bottom end of the glass base material; performing a sintering treatment of the porous glass base material presetting, for each feeding distance L of the porous glass base material, a greater-than-1 target value αS (L) of an elongation rate in a straight body portion of the porous glass base material calculated based on a ratio Vw/Vf, and controlling at least one of a temperature of the heating furnace and a feeding speed of the porous glass base material such that a measured value α of the elongation rate of the porous glass base material matches with the target value αS (L).
Claims8
A porous glass base material sintering method for making a transparent glass moving a hung-down porous glass base material relatively to a heating furnace and heating the porous glass base material sequentially from one end to the other end, comprising:
- measuring a feeding speed Vf of the porous glass base material and a movement speed Vw of a bottom end of the porous glass base material;
- presetting, for each feeding distance L of the porous glass base material, a target value αS(L) of an elongation rate in a straight body portion of the porous glass base material to be greater than one;
- presetting, for each feeding distance L of the porous glass base material, a set temperature T0(L) of the heating furnace;
- attaching a weight near the bottom end of the hung-down porous glass base material, the weight acting a tension on the porous glass base material during a sintering treatment, the weight being provided with a plurality of marks on a side surface of the weight, the plurality of marks being arranged spaced apart from each other in the longitudinal direction of the porous glass base material;
- and
- performing the sintering treatment of the porous glass base material while controlling a furnace temperature of the heating furnace to be T0(L)+ΔT, such that a measured value α of the elongation rate of the porous glass base material matches with the target value αS(L), the measured value α of the elongation rate being calculated as a ratio Vw/Vf, and ΔT being a temperature deviation proportional to an additive inverse of any one of a deviation and a ratio of the measured value α and the target value αS(L), wherein
- the porous glass base material has a core rod with a constant outer diameter in a longitudinal direction, with glass microparticles being deposited on an outer periphery of the core rod, and
- measuring the movement speed Vw of the bottom end of the porous glass base material includes:
- obtaining an image by photographing the plurality of marks by a camera tracking the porous glass base material;
- and
- processing the image to calculate the movement speed Vw of the bottom end of the porous glass base material based on a position of the camera and positions of the plurality of marks in the image.
8 more elements
A porous glass base material sintering method for making a transparent glass moving a hung-down porous glass base material relatively to a heating furnace and heating the porous glass base material sequentially from one end to the other end, comprising:
- measuring a feeding speed Vf of the porous glass base material and a movement speed Vw of a bottom end of the porous glass base material;
- presetting, for each feeding distance L of the porous glass base material, a target value αS(L) of an elongation rate in a straight body portion of the porous glass base material to be greater than one;
- presetting, for each feeding distance L of the porous glass base material, a feeding speed Vf0(L) of the porous glass base material;
- attaching a weight near the bottom end of the hung-down porous glass base material, the weight acting a tension on the porous glass base material during a sintering treatment, the weight being provided with a plurality of marks on a side surface of the weight, the plurality of marks being arranged spaced apart from each other in the longitudinal direction of the porous glass base material;
- and
- performing the sintering treatment of the porous glass base material while controlling a feeding speed of the porous glass base material to be Vf0(L)+ΔVf, such that a measured value α of the elongation rate of the porous glass base material matches with the target value αS(L), the measured value α of the elongation rate being calculated as a ratio Vw/Vf, and ΔVf being a feeding speed deviation of the porous glass base material that is proportional to any one of a deviation and a ratio of the measured value α and the target value αS(L), wherein
- the porous glass base material has a core rod with a constant outer diameter in a longitudinal direction, with glass microparticles being deposited on an outer periphery of the core rod, and
- measuring the movement speed Vw of the bottom end of the porous glass base material includes:
- obtaining an image by photographing the plurality of marks by a camera tracking the porous glass base material;
- and
- processing the image to calculate the movement speed Vw of the bottom end of the porous glass base material based on a position of the camera and positions of the plurality of marks in the image.
8 more elements
A method comprising:
- depositing glass microparticles on an outer periphery of a core rod with a constant outer diameter in a longitudinal direction to form a porous glass base material;
- presetting, for each feeding distance L of the porous glass base material, a target value αS(L) of an elongation rate in a straight body portion of the porous glass base material to be greater than one;
- presetting, for each feeding distance L of the porous glass base material, a set temperature T0(L) of a heating furnace;
- attaching a weight near a bottom end of the porous glass base material, the weight acting a tension on the porous glass base material during a sintering treatment, the weight being provided with a plurality of marks on a side surface of the weight, the plurality of marks being arranged spaced apart from each other in the longitudinal direction of the porous glass base material;
- moving, while hung-down, the porous glass base material relatively to the heating furnace while heating the porous glass base material sequentially from one end to the other end;
- and
- while moving and heating the porous glass base material:
- measuring a feeding speed Vf of the porous glass base material,
- obtaining an image by photographing the plurality of marks by a camera tracking the porous glass base material,
- processing the image to calculate a movement speed Vw of the bottom end of the porous glass base material based on a position of the camera and positions of the plurality of marks in the image, and
- controlling a furnace temperature of the heating furnace to be T0(L)+ΔT, ΔT being a temperature deviation determined such that a deviation between a measured value α of the elongation rate of the porous glass base material and the target value αS(L) is substantially minimized, the measured value α of the elongation rate being calculated as a ratio Vw/Vf.
8 more elements
Dependencies are inferred from the claim text.