Inventors:
William M. Jones - Parma OH
Mark S. Freas - Cleveland OH
Assignee:
The North American Manufacturing Company - Cleveland OH
International Classification:
F23C 500
Abstract:
When a burner is supplied with preheated air, the temperature and density of the preheated air may vary during operation of the burner. When the density of the air supplied to a burner varies, it is necessary to vary the rate at which fuel is supplied to the burner in order to maintain a predetermined air-fuel ratio. To effect a variation in fuel flow with burner air density, the present invention utilizes a secondary air flow to simulate the heated flow of air to the burner. The flow rate of the secondary air varies in a manner which is a direct function of variations in the rate of flow of the heated burner air. Changes in the rate of flow of the secondary air are sensed at a predetermined reference temperature. The sensed variations in the secondary air flow are utilized to effect a corresponding change in the rate of fuel flow to maintain a constant air-fuel ratio.