Abstract: A low NO.sub.x burner combustion system which may be adjusted for optimum burn rates, temperature and oxygen levels. The burner incorporates a plurality of gas nozzles which individually inspirate a portion of the combustion air and a spin vane diffuser to rotate and mix the gases within the primary combustion zone. The diffuser is axially adjustable in order to vary the distance between the vane and the first combustion zone while the blades of the diffuser can be angularly adjusted to optimize the rotation and mix of the gases. Air for combustion is supplied through primary, secondary and tertiary passages to create distinct combustion zones for complete combustion. The flow rate of the combustion air is controlled through a damper in accordance with the burn characteristics. Further reductions in noxious emissions are accomplished by recirculating flue gases and mixing such gassed directly with combustion fuel prior to introduction into the combustion chamber through eductor nozzles.

Abstract: A low NO.sub.x burner combustion system which may be adjusted for optimum burn rates, temperature and oxygen levels. The burner incorporates a plurality of gas nozzles which individually inspirate a portion of the combustion air and a spin vane diffuser to rotate and mix the gases within the primary combustion zone. The diffuser is axially adjustable in order to vary the distance between the vane and the first combustion zone while the blades of the diffuser can be angularly adjusted to optimize the rotation and mix of the gases. Air for combustion is supplied through primary, secondary and tertiary passages to create distinct combustion zones for complete combustion. The flow rate of the combustion air is controlled through a damper in accordance with the burn characteristics. The angular and axial position of the diffuser and the damper control of combustion air can be automatically adjusted throughout the firing range of the burner in response to demand levels.