Alzeta Corporation

Robert W Nickeson

John D Sullivan

Luis H Morales

The 'fuel-air pressure ratio' combustion control system for maintaining a selected fuel-air ratio for a combustion apparatus supplied with air at a substantially constant volumetric rate is improved by means for adjusting the flow rate of fuel in relation to temperature fluctuations of the air. A temperature sensor positioned in the air stream before it mixes with the fuel is connected to a converter which transmits converted temperature signals from the sensor as adjustments of a remote control, secondary valve in the fuel line downstream of a primary valve regulating the flow of fuel. Fuel temperature fluctuations can also be converted into adjustments of the remote control, secondary valve.

Temperature-compensated combustion control

Combustion control systems for maintaining a selected fuel-air ratio for a combustion apparatus supplied with air at a substantially constant volumetric rate are improved by means for adjusting the flow rate of fuel in relation to temperature fluctuations of the air. A temperature sensor positioned in the air stream before it mixes with the fuel is connected to a converter which transmits converted temperature signals from the sensor as adjustments of a remote control-flow regulator in the fuel line or in the air stream. Thus, if the flow regulator is in the fuel line, a drop in air temperature will cause an increase of the fuel flow rate. Conversely, a rise in air temperature will result in a reduced fuel flow rate. If the flow regulator is in the air stream, a drop in air temperature will cause a decrease in the air flow rate, while a rise in air temperature will result in increased air flow rate. The invention is also applicable to temperature variations of the fuel by using the three basic components: a temperature sensor, a converter and a remote control-flow regulator.

Combustion control with temperature compensation

The present invention is a method and apparatus to improve the utilization of flow and power characteristics of a combustion air fan over the full range of burner operation. More specifically, it is an apparatus and a method of operation that uses a high flue-gas-to-air ratio over most of the boiler operating range to maximize thermal efficiency, but which switches to a lower ratio of flue-gas-to-air, or no flue gas in the limiting case, at the high end of the mass flow range of the burner to minimize the size of the fan housing and fan motor. When applied to current generation ULNBs, fan size can be reduced about 50% and operating power consumption can be reduced by about 50% without adversely affecting NO emissions.

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Pleasanton, CA, United States of America

Robert W Nickeson