US 4,003,615 AGranted

Coated carbon electrode having an inner coating of low resistance material

OwnerShigeru Sugainventor

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Abstract

A carbon electrode for use in an arc lamp used for determining light fastness which has a central core of light emitting material combined with stabilizers and graphite surrounded by a first coating of low resistance electrically conductive material, preferably copper or aluminum. The thus-coated core is further coated with a second coating of graphite and adhesive and inserted into a cylindrical carbon tube. The tube, except for the top and bottom portions is coated around the outside with a third protective coating, and the base and bottom portions of the tube are coated with a metallic coating electrically connected to the first coating of low resistance material spaced from the third coating. The third and fourth coatings may be joined together, provided that the resistance of these two coatings is greater than the resistance of the first coating.

Claims10

Dependent claims

A carbon electrode for use in an arc lamp used for determining light fastness, said carbon electrode comprising:

a round central core portion comprised of a mixture of:
light emitting materials,
stabilizer material, and
graphite;
a first coating of low resistance electrically conductive material covering the outside, but not the ends, of said central core portion;
a second coating of adhesive and graphite surrounding said first coating;
a cylindrical carbon tube with said first and second coated central portion inserted, dried, and adhered thereinto;
a third protective coating surrounding the outside of said cylindrical carbon cylinder above the bottom of said carbon cylinder and beneath the top end of said carbon cylinder;
and
a fourth metallic coating covering the bottom end of said first and second coated central core and said carbon tube and surrounding the outside base of said cylindrical carbon tube, spaced from said third coating, electrically connected to said first coating and having a higher electrical resistance than said first coating.

7 more elements

Dependencies are inferred from the claim text.