초록 ▼

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 wh

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. In such a mass flow system, the linkage acts as a backup for maintenance purposes and the like.

대표청구항 ▼

[ What is claimed is:] [1.] A system adapted for use in an hot asphalt mix plant, comprising mass flow means for controlling a fuel/air ratio for at least one fuel supplied to a burner by measuring at least two parameters consisting of fuel flow, air flow and flue gas flow, andmeans for preventing r

[ What is claimed is:] [1.] A system adapted for use in an hot asphalt mix plant, comprising mass flow means for controlling a fuel/air ratio for at least one fuel supplied to a burner by measuring at least two parameters consisting of fuel flow, air flow and flue gas flow, andmeans for preventing rich operation of the burner when changing burner firing rate and for permitting operation of the burner in lieu of the mass flow means when the latter is non-operational.