Inventors:
John O'Hara - Annville PA
Fred L. Fuhrman - Jonestown PA
David R. Wolfe - Lititz PA
Bruce C. Irwin - Palmyra PA
Assignee:
Hauck Manufacturing Company - Lebanon PA
International Classification:
F27B 940, F23N 500
Abstract:
A draft control for material processing apparatus, such as asphalt plants, having a chamber through which material to be processed is passed for contact with combustion gases and heat originating in a fuel supplied burner which may require a draft to draw air into the chamber for complete combustion of burner supplied fuel and to exhaust the products of combustion and other gaseous materials from the chamber. The air pollutants and the percent oxygen in the exhausted gases are monitored, and the draft is adjusted between minimum and maximum values for a given burner set point when the air pollutant content of the stack gases exceeds a predetermined maximum limit. The direction of draft adjustment is determined by the percent oxygen in the exhaust gases.