Draft controlled boiler fuel nozzle

摘要

A multi-fuel boiler having multiple, independent draft or combustion air sources and controls. A conventional oil/gas burner and nozzle assembly is fitted to an injector tube and isolated from a thermal transfer medium. A butterfly valve is supported in the injector tube and a motorized linkage directs valve operation. When the burner is non-operational, the valve prevents secondary combustion air from passing through the oil/gas burner to effect combustion in the firebox.