The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 12, 1994
Filed:
Oct. 22, 1992
Han K Park, Allegheny County, PA (US);
Vesuvius Crucible Company, Pittsburgh, PA (US);
Abstract
A sight tube for an optical temperature measuring device suitable for immersion in molten steel comprises an elongated, cylindrical body having an optical sighting bore therein extending axially from an open end of the body to a closed end. The body is a carbon bonded alumina graphite material made from a mix consisting of, in weight percent, between about 5-45% graphite; between about 20-85% alumina; 0 to 15% anti-oxidant; and between about 3-20% phenolic resin binder. The mixture is isostatically pressed in the desired body shape and fired at a temperature in excess of 1400.degree. C. in a reducing atmosphere. The graphite is preferably a high purity flake graphite, greater than 99% pure. The alumina is preferably 'brown' fused alumina grain having minimum amounts of volatile elements: sodium (Na), potassium (K), boron (B), phosphorous (P), sulphur (S) and chlorine (Cl). The sodium content, present as Na.sub.2 O in the alumina source is less than 0.05% by weight, and preferably no more than 0.02% by weight.