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:
Jun. 05, 1990
Filed:
Jun. 24, 1986
Alfred J Martenson, Richland, WA (US);
William J Johnson, Kennewick, WA (US);
Pyrofoam, Inc., Kennewick, WA (US);
Abstract
Obsidian having less than one percent of combined water is expanded to a volume many times the original by a two stage heating process carried out in at least one refractory-lined, rotary kiln. It is heated gradually by a first flame to a temperature of 1800-1900 F., then subjected to a second flame at a temperature of 2400-2500 F. for a very few minutes. The heating is carried out in the presence of dust which has a softening point considerably above those temperatures. The dust prevents the softened obsidian from sticking to itself or to the lining of the kiln. In some embodiments, the entire process is carried out in a single kiln with both flames entering the discharge end of the kiln, the first flame being directed toward the feed end and the second flame directed transversely or toward the discharge end. In another embodiment, the obsidian is gradually heated in a first kiln, then immediately fed to a second rotary kiln where the second flame enters the feed end and is directed toward the discharge end. In the second embodiment, combustion gases from the second kiln are recycled back to the first kiln to aid in the gradual heating step.