Glass manufacturing apparatus, a structural member thereof and method for heating the structural member by conduction heating
View Patent ↗A hollow tubular body for molten glass in which local-overheating is reduced at the time of conduction heating. The hollow tubular body has a platinum or platinum alloy hollow tube, used for conduction heating, wherein a platinum or platinum alloy ring electrode is joined to the outer circumference of the hollow tube, a lead-out electrode is joined to an outer edge of the ring electrode, and a thick portion is provided in at least the joint portion closest to the lead-out electrode, of the ring electrode and in the vicinity thereof.
1. A hollow tubular body used for conduction heating, comprising:
a hollow tube made of one of platinum and a platinum alloy;
a ring electrode joined to an outer circumference portion of the hollow tube, the ring electrode being made of one of platinum and a platinum alloy; and
a lead-out electrode joined to an outer edge portion of the ring electrode, wherein the hollow tube is provided with a thick portion in at least a joint portion of the ring electrode and in the vicinity thereof, the thick portion being made of a same material as the hollow tube.
2. A hollow tubular body used for conduction heating, comprising:
a hollow tube made of one of platinum and a platinum alloy;
a ring electrode joined to an outer circumference of the hollow tube; and
a lead-out electrode joined to an outer edge of the ring electrode, wherein the hollow tube is provided with a thick portion over its whole circumference in a joint portion to the ring electrode, the thick portion being made of a same material as the hollow tube.
3. The hollow tubular body according to claim 1 or 2 , wherein the thick portion satisfies the following formulas (1) and (2):
0.4d≦L≦1.2d (1) and
1.2t 0 ≦t≦1.7t (2)
where L represents a length (mm) of the thick portion in an area excluding the joint portion to the ring electrode, d represents an outer diameter (mm) of the hollow tube, t represents a wall thickness of the thick portion and t 0 represents a wall thickness (mm) of the hollow tube in the area excluding the thick portion.
4. The hollow tubular body according to claim 1 or 2 , wherein the thick portion is formed with an angle of 20° or more with respect to a linear center line, extending from a center of the ring electrode to a midpoint of the joint portion to the lead-out electrode.
5. The hollow tubular body according to claim 1 or 2 , wherein the thick portion reduces local-overheating in the joint portion closest to the hollow tube, of the lead-out electrode.
6. The hollow tubular body according to claim 1 or 2 , wherein a length of the thick portion in an area excluding the joint portion to the ring electrode is from 30 to 800 mm.
7. The hollow tubular body according to claim 1 or 2 , wherein an outer diameter of the hollow tube is from 50 to 800 mm.
8. The hollow tubular body according to claim 1 or 2 , wherein a wall thickness of the thick portion is from 0.5 to 8 mm.
9. The hollow tubular body according to claim 1 or 2 , wherein a wall thickness of the hollow tube in an area excluding the thick portion is from 0.4 to 5 mm.
10. The hollow tubular body according to claim 1 or 2 , wherein a wall thickness of the ring electrode is substantially the same as that of the lead-out electrode.