Pressure atomization depends on the oil pressure inside the nozzle tip to spray a fine mist of oil, very similar to a Windex spray bottle. The micronized oil droplets are flung into the burner head, where they are thoroughly mixed with the combustion air and ignited. As mentioned above, the pressure at the oil nozzle is the key factor in the atomization process; therefore, your oil pump and pressure regulator are the key components in this system. The pump needs to be able to meet the gallons per hour (gph) requirement for the burner/boiler to meet their load capacity. The pressure regulator is set in accordance to the firing rate which is normally between 100-300 (psi). The turndown ratio for a pressure atomizing burner is normally only 3:1 or 4:1.
However, Preferred has just designed and shipped our first high turndown, 6:1 guaranteed, pressure atomized API-AF burners.
These API-AF burners are UL listed for No. 2 oil firing, utilizing pressure atomization. We demonstrated a turndown of 8:1 on pressure atomized oil firing to the UL inspector, extending the normal turndown ratio which is usually only 3:1 or 4:1