High ratio modulation combustion system and method of operation

摘要

A combustion system is shown having a combustion chamber into which fuel is introduced and ignited in the presence of air to create products of combustion which are routed through an exhaust vent. A forced draft burner intakes air and fuel and ignites these components to supply heat to the combustion chamber. A valve is provided within the exhaust vent for varying the degree of restriction within the exhaust vent. A modulation drive motor is connected to the variable restriction in the exhaust vent and to the air and fuel supply sources for increasing the exhaust vent back pressure as the ratio of air and fuel being supplied to the combustion chamber are decreased.