Stranded outer lead wire assembly for quartz pinch seals
View Patent ↗A stranded outer lead wire assembly for a quartz pinch sealed lamp. The stranded outer lead wire assembly is a butt welded connection of a refractory metal outer pinch lead (e.g., molybdenum solid wire) and a stranded soft metal lead wire (e.g., nickel wire strands twisted together). The assembly is prefabricated and then welded to sealing foil to make a four part foliated lead wire assembly for pinch sealing in the quartz outer jacket. The foliated lead wire assembly and a quartz envelope lamp utilizing the stranded outer lead wire assembly are also claimed. The sealing machine is adapted to protect the stranded outer lead assembly with a water cooled sleeve. In an embodiment, the outer end of the stranded lead is fused to prevent fraying.
1. A quartz envelope lamp with a stranded outer lead wire comprising:
an outer lead wire assembly comprising a butt welded connection of a molybdenum solid wire outer sealing lead to a stranded outer lead wire;
a sealing foil welded to the outer lead wire assembly; and
a hermetic quartz seal formed around the sealing foil.
2. The quartz envelope lamp of claim 1 wherein:
the hermetic quartz seal is a pinch seal.
3. The quartz envelope lamp of claim 1 wherein:
the stranded outer lead wire comprises nickel wire strands twisted together.
4. The quartz envelope lamp of claim 1 wherein:
the molybdenum wire is doped to minimize recrystallization embrittlement.
5. The quartz envelope lamp of claim 1 wherein:
the molybdenum wire is doped with lanthanum oxide LaO3.
6. The quartz envelope lamp of claim 1 wherein:
the stranded outer lead wire and the solid molybdenum wire are approximately coaxially aligned in the butt weld; and
the butt weld comprises melted nickel wire strands that fused over the end of the solid molybdenum wire.
7. A lead wire for hermetically sealing in a quartz envelope lamp comprising:
a stranded outer lead wire butt welded to a molybdenum solid wire outer sealing lead; and
the outer sealing lead welded to a molybdenum sealing foil.
8. The lead wire of claim 7 , further comprising:
an inner sealing lead welded to an inner end of the sealing foil.
9. The lead wire of claim 7 , wherein:
the stranded outer lead wire comprises nickel wire strands; and
the strands are fused together at an outer end thereof.
10. The lead wire of claim 7 , wherein:
the molybdenum wire is doped to minimize recrystallization embrittlement.
11. The lead wire of claim 7 , wherein:
the molybdenum wire is doped with lanthanum oxide LaO3.
12. The lead wire of claim 7 , wherein
the stranded outer lead wire and the solid molybdenum wire are substantially coaxially aligned in the butt weld; and
the butt weld comprises melted nickel wire strands that fused over the end of the solid molybdenum wire.
13. A method of manufacturing a quartz envelope lamp with a stranded outer lead wire, comprising the steps of:
forming a stranded outer lead wire assembly by butt welding an inner end of a stranded lead wire to an outer end of a molybdenum solid wire outer sealing lead;
welding the molybdenum outer sealing lead to an outer end of a sealing foil;
welding an inner sealing lead to an inner end of the sealing foil; and
hermetically sealing the quartz envelope around the sealing foil.
14. The method of claim 13 wherein:
the step of forming the stranded outer lead wire assembly is performed before the step of welding the molybdenum outer sealing lead to an outer end of a sealing foil.
15. The method of claim 13 wherein the step of forming the stranded outer lead wire assembly further comprises:
approximately coaxially aligning the stranded outer lead wire and the solid molybdenum wire while butt welding; and
applying heat sufficient to melt nickel wire strands to fuse over the end of the solid molybdenum wire.
16. The method of claim 13 further comprising the step of:
using a sleeve to protect the stranded outer lead wire assembly during the step of sealing the quartz envelope.
17. The method of claim 16 , wherein:
the sleeve is cooled by flowing liquid or gas coolant.
18. The method of claim 13 further comprising:
using a quartz pinch sealing method.
19. The method of claim 13 further comprising:
using lanthanated molybdenum wire.