Structure and Classification of Oil Burners
Oil combustion characteristics
Oil is a liquid fuel, the boiling point is always below its flash point, so the oil combustion is carried out in gaseous form. No combustion occurs in the liquid but gaseous. So droplet combustion includes three processes: evaporation, diffusion and combustion , and those processes carry out simultaneously.
The main characteristics are as below:
(1) Oil burn only in gaseous form;
(2) The burning is diffusive and requires atomization;
(3) It has different thermal decomposition features under different situations;
Oil burner structure
For the full combustion of fuel oil, it need to improve the atomization of the oil. If need let mist and air mixes well, that wad achieved by the burner . Burner is the key equipment of the oil-fired boiler, which consists of injector portion (atomizer), adjusting the wind section, ignition and combustion stabilization equipment, electrical systems and motors and servo motors, and so on.
Fuel injection device include pump, pump control valves, filters, oil preheaters, solenoid valves, fuel injectors, oil return valve and other components;
Adjust the air flow part by the fan, air baffle, adjusting sleeve, shell and other components .
Ignition and combustion stabilization equipment by a transformer, ignition electrodes and other components.stable combustion device comprises adjustable air combustion head and disk components.
Electrical system by the flame sensor, combustion process controller, fuel heating controller and other components.
Servo motor provide power for the fan motor, pump, air damper, oil regulator.
(1) Mechanical atomization
Mechanical atomization is use the high oil pressure, and the oil discharged from the orifice at high speed to achieve atomization. Mechanical atomizing nozzle usually use centrifugal nozzle.
Mechanical atomizing nozzle is composed of : swirl chamber, oil and grease nipple nuts and other parts, has a certain pressure, fuel temperature, and through the hole and sump into the tangential grooves , and access to high speed, then into the cyclone chamber. Oil produced strong centrifugal rotation in the swirl chamber, causing the groove pulsating, ejected from the nozzle holes and form a hollow cone-shaped film. Under turbulent circumstances, oil through the orifice diffusion, combined with the centrifugal force, forming a surface tension and crushed into many small oil particles, finally achieve the purpose of atomization.
(2) Rotor spray
The working principle is this: the fuel will be sent to the high-speed rotating cup-shaped device (3000~5000r/min) through the hollow shaft. Under the centrifugal force, the oil will form a thin oil film on the inner wall of the rotor and fly out along the cup, and will be atomized into super fine oil particles. At the same time, the blower blades will blow out the air through cup and guide vane. As the first air rotation direction is opposite to the oil droplets, so the oil droplets will be further atomized.
Oil burner classification
Burner is combination by fuel delivery, atomization devices, air circuit devices. Combined into one, called oil burner. In addition it can better ensure complete combustion of the fuel supplied to the boiler, it also has automatic control, alarm and protection devices. We took apart the base body, namely oil system, air system, and thus circuit systems separately. Depending on the fuel, the burner is divided into light oil (kerosene, diesel), heavy oil (residue) and oil burner.
According to the number of burner nozzle and regulation in different ways, the burner is divided into primary, secondary, tertiary and proportional. Primary has one injector, secondary has two fuel injectors, tertiary has three injectors. Proportional burner power continuously changes, it changes determined by the demand of the boiler.Other burner power change is determined by the number of injectors.