Apparatuses and methods for continuous production of glass tubing

Patent metadata

Field	Value
Publication number	US-10927029-B2
Application number	US-201816201472-A
Country	US
Kind code	B2
Filing date	Nov 27, 2018
Priority date	Nov 30, 2017
Publication date	Feb 23, 2021
Grant date	Feb 23, 2021

Abstract

An apparatus for producing composite glass tube with a plurality of glass layers includes a plurality of cylindrical containers of increasing inner dimensions concentrically arranged and stationary. Each cylindrical container includes a side wall, bottom wall, and a delivery ring. Adjacent cylindrical containers define an annular chamber, a flow control region, and an annular flow channel therebetween. The apparatus includes at least one flow control valve positioned in the flow control region and translatable relative to the adjacent cylindrical containers. Translation of the flow control valves relative to the cylindrical containers is operable to change an impedance to flow of molten glass through the flow control region, thereby modifying an overall flow rate or circumferential distribution of molten glass from the cylindrical containers. Systems and methods for producing composite glass tube using the apparatus are also disclosed.

First claim

What is claimed is:

1. A method of producing a glass tube comprising:
introducing a first molten glass composition to an annular chamber defined between an inner cylindrical container and an outer cylindrical container, wherein a bottom wall of the outer cylindrical container is spaced apart from the inner cylindrical container to define an annular flow channel;
passing the first molten glass composition through the annular flow channel to an outer delivery ring coupled to the bottom wall of the outer cylindrical container and defining a central opening in the bottom wall of the outer cylindrical container;
translating at least one flow control valve disposed in the annular chamber, wherein translation of the at least one flow control valve relative to the outer cylindrical container changes an impedance to flow of the molten glass into the annular flow channel, thereby changing a thickness of the glass tube; and
separating the first molten glass composition from a distal end of the outer delivery ring to form a first molten glass layer of the glass tube.

2. The method of claim 1 , further comprising producing a gas flow proximate to the outer delivery ring.

3. The method of claim 1 , wherein a plurality of flow control valves are disposed in the annular chamber defined between the inner cylindrical container and the outer cylindrical container, each of the plurality of flow control valves being independently translatable relative to the outer cylindrical container.

4. The method of claim 3 , further comprising adjusting a siding of the first molten glass layer by translating one or more of the plurality of flow control valves relative to the other of the plurality of flow control valves to change the circumferential distribution of the first molten glass composition flowing through the annular flow channel.

5. The method of claim 1 further comprising:
introducing a second molten glass composition to the inner cylindrical container, the inner cylindrical container comprising a blow tube disposed within the inner cylindrical container;
passing the second molten glass composition through an inner annular flow channel defined between the blow tube and the inner cylindrical container to an inner delivery ring coupled to the inner cylindrical container and defining a central opening of the inner cylindrical container; and
separating the second molten glass composition from the inner delivery ring to produce a second molten glass layer of the glass tube.

6. The method of claim 5 , further comprising contacting the first molten glass layer separated from the outer delivery ring with the second molten glass layer separated from the inner delivery ring.

7. The method of claim 5 , further comprising adjusting a thickness or a siding of the second molten glass layer by translating the blow tube vertically or horizontally relative to the inner cylindrical container to change an impedance to flow of the second molten glass composition between the blow tube and the inner cylindrical container.

8. The method of claim 5 , wherein the inner cylindrical container comprises an inner flow control valve disposed within the inner cylindrical container and translatable relative to the inner cylindrical container, where the method further comprises adjusting a thickness or a siding of the second molten glass layer by translating the inner flow control valve vertically or horizontally relative to the inner cylindrical container to change an impedance to flow of the second molten glass composition from the inner cylindrical container to the inner delivery ring.

9. The method of claim 5 , wherein the first molten glass composition has a coefficient of thermal expansion (CTE) different than the second molten glass composition.

10. The method of claim 5 , further comprising:
introducing a third molten glass composition to a second annular chamber defined between the outer cylindrical container and a second outer cylindrical container;
passing the third molten glass composition from the second annular chamber, through a second annular flow channel defined between a bottom wall of the second outer cylindrical container and the outer cylindrical container, to a second outer delivery ring; and
separating the third molten glass composition from the second outer delivery ring to produce a third molten glass layer of the glass tube.

11. The method of claim 10 , further comprising adjusting an average thickness or a circumferential thickness profile of the third molten glass layer by translating at least one of a plurality of flow control valves disposed in the second annular chamber relative to the second outer cylindrical container.

12. A system for producing glass tubing, the system comprising:
an apparatus comprising:
an inner cylindrical container including an inner delivery ring extending from a bottom of the inner cylindrical container, the inner delivery ring defining a central opening in the bottom of the inner cylindrical container;
an outer cylindrical container concentrically arranged to surround the inner cylindrical container and spaced apart from the inner cylindrical container to define an annular chamber therebetween, the outer cylindrical container comprising a side wall and a bottom wall extending radially inward from the side wall to an outer delivery ring extending downward from the bottom wall, the outer delivery ring defining a central opening in the bottom wall of the outer cylindrical container, wherein the bottom wall, the side wall, or both of the outer cylindrical container are spaced apart from the inner cylindrical container to define a flow control region and an annular flow channel extending between the outer cylindrical container and the inner cylindrical container and from the flow control region to the outer delivery ring;
at least one flow control valve disposed in the annular chamber;
at least one positioner operatively coupled to the at least one flow control valve and operable to translate the at least one flow control valve relative to the outer cylindrical container, the inner cylindrical container, or both, wherein translation of the at least one flow control valve by the positioner is operable to change an impedance to flow of a molten glass composition through the flow control region; and
a blow tube disposed within the inner cylindrical container and operable to deliver a gas flow proximate the inner delivery ring;

a sensor disposed downstream of the apparatus, the sensor operable to measure at least one dimension of the glass tube produced by the apparatus; and
a control system communicatively coupled to the at least one positioner and to the sensor, the control system comprising a processor and one or more memory modules communicatively coupled to the processor.

13. The system of claim 12 , further comprising machine readable instructions stored in the one or more memory modules that cause the system to perform at least the following when executed by the processor:
measure a dimension of the glass tube;
compare the dimension of the glass tube to a target dimension of the glass tube; and
send a control signal to the at least one positioner to change a position the at least one flow control valve based on the comparison of the dimension of the glass tube to the target dimension, wherein changing the position of the at least one flow control valve produces a change in the dimension of the glass tube.

14. The system of claim 12 , wherein the sensor is operable to measure at least one of the overall average thickness of the glass tube, an average thickness of one or more than one glass layer of the glass tube, a ci

Assignees

• Corning Inc

Inventors

• Fisher Jr Dale Madard
• Posada-Pineda David

Classifications

• C03B17/04

  Forming tubes or rods by drawing from stationary or rotating tools or from forming nozzles · CPC title

• C03B17/025 Primary

  Tubes or rods · CPC title