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:
Aug. 14, 2012
Filed:
Jan. 08, 2010
Masanori Fukui, Akita, JP;
Hiroshi Kishi, Akita, JP;
Masaki Morikawa, Akita, JP;
Japan Super Quartz Corporation, Akita, JP;
Abstract
A vitreous silica crucible manufacturing apparatus includes a plurality of carbon electrodes configured to heat and melt raw material powder by arc discharge, and a value of a ratio R/Rof a diameter Rof a front end of each of the carbon electrodes to a diameter Rof a base end is set in a range of 0.6 to 0.8. Each carbon electrode has a diameter reduction portion formed at a front end position and reduced in diameter from a diameter Rof a base end side to the diameter Rof the front end. When a length of the diameter reduction portion is L, the diameter of the front end is R, the diameter of the base end is R, an angle between the axis lines of the carbon electrodes is θ, and X=(R−R)/2, a value of L−(X/tan(θ/2)) is set in a range of 50 to 150 mm.