Abstract: As electronic programmable valve positioning linkage for a burner used in a hot mix asphalt plant is associated with fuel, air and optionally flue gas recirculation valve motors. To avoid an undesired rich condition which might result in an explosive condition, the linkage employs a program logic which changes a valve position, depending on increase or decrease of the burner output, in response to a temperature controller and thereby maintain an acceptable lean condition. The air valve motor is controlled by the temperature controller when burner output is to be increased with the fuel valve motor following the air valve motor, and the fuel valve motor is controlled when the burner output is to be decreased with the air valve motor following the fuel valve motor. In conjunction with the linkage, a mass flow system can be provided to calculate fuel/air and/or flue gas recirculation ratios based upon measurement of air flow, fuel flow and flue gas flow.

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.

Abstract: A combination oil and gas fired burner includes a body, an air nozzle and an end plate. The end plate is mounted on the upstream end of the body and holds the air nozzle in place within the body. An atomizing assembly carried by the end plate is fitted within an aperture in the air nozzle adjacent the combustion chamber. The burner is readily disassembled by removing the end plate, atomizing assembly and the air nozzle from the body without requiring complete disassembly and removal of the body from its mounting plate. On the reassembly, fuel and air flow openings in the burner are returned to their original angular orientation so that there is no need to readjust the fuel delivery system.