The core combustion assembly (or burner) of an oil-fired furnace primarily consists of a fuel nozzle, an air register, and an igniter. The function of the fuel nozzle is to atomize the fuel into fine droplets, facilitating rapid and complete combustion; common types include mechanical atomizing nozzles (such as pressure-atomizing and spill-return types), rotary cup nozzles, and dual-fluid nozzles (such as steam-atomizing and air-atomizing types).
The air register is designed to generate swirl and ensure proper air distribution, allowing the air supplied to the furnace to mix uniformly with the injected fuel mist, thereby enhancing combustion efficiency. The igniter comprises two electrode rods made of a heat-resistant aluminum-magnesium alloy, with a gap of 3–4 mm between their tips; when a high voltage of 5,000–10,000 V is applied, an electric arc sparks across the gap, igniting the fuel injected into the furnace chamber.
