A thermally efficient process for the expansion of perlite ore is described. The inlet port and burner of a perlite expansion chamber (preferably a vertical expander) are enclosed such that no ambient air can enter the chamber. Air and fuel are metered to the burner with the amount of air being controlled such that the fuel/air premix contains at least enough air to start and maintain minimum combustion, but not enough to provide stoichiometric combustion. At a point immediately above the burner, additional air is metered into an insulated enclosure surrounding the expansion chamber where it is preheated by the heat passing through the chamber walls. This preheated additional air is then circulated back to the burner where it provides the remainder of the air needed for combustion, normally full combustion. Flow of the burner fuel/air premix and the preheated additional air is controlled so as to maintain a long luminous flame throughout a substantial portion of the expansion chamber and also to form a moving laminar layer of air on the inner surface of the expansion chamber. Preferably the burner is a delayed mixing gas burner which materially aids in the generation of the long luminous flame.
Lightweight Asphalt Based Building Materials And Process For Making Same
Kenneth L. Jenkins - Littleton CO Stanley C. Suhaka - Englewood CO Rick L. Dolin - Littleton CO Allan R. LaRoche - Lewiston ME Robert E. Hodgson - Littleton CO Neil R. Such - Englewood CO Douglas D. Smith - Highlands Ranch CO Frank R. Newton - Littleton CO Richard N. Cunningham - Littleton CO
Assignee:
Manville Corporation - Denver CO
International Classification:
B32B 1102 B32B 1110 B05D 112
US Classification:
428143
Abstract:
A lightweight asphalt roofing product wherein the asphalt-based coating has a specific gravity less than 1. A lightweight filler is used which has an effective specific gravity in the range of 0. 10-0. 50 and is present in the coating in the range of 3%-25% by weight of the filled coating. In a preferred embodiment, the filler particles have hollow, gas filled inclusions, and comprise expanded perlite particles or expanded permicite particles.