Methods and apparatus for processing glass

1. A glass forming apparatus comprising:

a transition member including a transition chamber;

a slot extension attached to a bottom portion of the transition member such that an interior volume of the slot extension is in fluid communication with the transition chamber; and

a mechanical reinforcement chosen from one of a first strut, a ridge, or combinations thereof; the mechanical reinforcement being attached to an exterior surface of the slot extension,

wherein: the transition chamber and an upper portion of the slot extension are covered by a refractory material; and a lower portion of the slot extension is not covered by a refractory material, and

wherein the mechanical reinforcement comprises a plurality of struts and the plurality of struts are embedded in the refractory material.

2. The glass forming apparatus of claim 1 , wherein the mechanical reinforcement is the first strut attached to a first exterior surface of the slot extension and extending outward from the first exterior surface.

3. The glass forming apparatus of claim 1 , wherein the lower portion has a height of at least 1 mm.

4. The glass forming apparatus of claim 1 , wherein:

a bottom portion of the slot extension comprises a bottom orifice, the bottom orifice having an orifice opening distance that varies along a width of the orifice.

5. The glass forming apparatus of claim 4 , wherein:

the orifice opening distance has a local minimum in a middle portion of the bottom orifice;

the orifice opening distance increases in a first direction moving away from the local minimum along the width of the orifice to a first local maximum in a first end portion of the bottom orifice;

the orifice opening distance increases in a second direction moving away from the local minimum along the width of the orifice to a second local maximum in a second end portion of the bottom orifice.

6. The glass forming apparatus of claim 1 , further comprising a lower flange and an upper flange configured to run current through the transition member, wherein the transition member comprises walls with variable thickness.

7. The glass forming apparatus of claim 6 , wherein the transition member comprises walls with variable thickness configured to maintain glass temperature in the transition chamber via resistive heating such that average glass temperature varies by less than 1° C. as glass moves through the transition chamber.

8. The glass forming apparatus of claim 6 , wherein the lower flange comprises a U-shaped end engaged with an end portion of the slot extension.

9. A process for forming a glass ribbon using the glass forming apparatus of claim 1 , the process comprising the steps of:

supplying a stream of molten glass through the transition chamber of the transition member;

passing the molten glass stream into the slot extension; and

drawing a glass ribbon from the slot extension.

10. A glass forming apparatus comprising:

a transition member including a transition chamber;

a slot extension attached to a bottom portion of the transition member such that an interior volume of the slot extension is in fluid communication with the transition chamber; and

a mechanical reinforcement chosen from one of a first strut, a ridge, or combinations thereof; the mechanical reinforcement being attached to an exterior surface of the slot extension,

wherein:

the slot extension is defined by:

a first slot wall and a second slot wall in the direction of a slot width, and a first slot end and a second slot end in the direction of a slot thickness;

the transition chamber is defined by:

a first body portion connected to the first slot wall along a width of the slot and extending upward from the slot;

a second body portion connected to the second slot wall along the width of the slot and extending upward from the slot;

a first edge portion connected to the first slot end along a thickness of the slot and extending upward from the slot; and

a second edge portion connected to the second slot end along the thickness of the slot and extending upward from the slot;

wherein the first body portion is connected to the second body portion at a first end by the first edge portion, and the first body portion is connected to the second body portion at a second end by the second edge portion;

a thickness of the transition chamber at a first predetermined height is a maximum distance between the first and second body portions in a thickness direction at that height;

the thickness of the transition chamber increases as a function of height as distance from the slot increases in a height direction;

a width of the transition chamber at a second predetermined height is the maximum distance between the first and second edge portions in the width direction at that height;

the width of the transition chamber decreases as a function of height as distance from the slot increases in the height direction; and

the thickness of the transition chamber at any given height of the transition chamber does not vary by more than 5% along 50% of the width of the transition chamber at that height.

11. The glass forming apparatus of claim 10 , wherein the first body portion and the second body portion each have a thickness that is less than a thickness of each of the first edge portion and second edge portion.

12. A process for forming a glass ribbon using the glass forming apparatus of claim 10 , the process comprising the steps of:

supplying a stream of molten glass through the transition chamber of the transition member;

passing the molten glass stream into the slot extension; and

drawing a glass ribbon from the slot extension.