Oil burner

An oil burner is a heating device which burns #1, #2 and #6 heating oils, diesel fuel or other similar fuels. The fuel is atomized into a fine spray usually by forcing it under pressure through a nozzle which gives the resulting flame a specific flow rate, angle of spray and pattern (variations of a cone shape). This spray is usually ignited by an electric spark with the air being forced through around it at the end of a blast tube, by a fan driven by the oil burner motor. The fuel pump is typically driven via a coupling connecting its shaft to that of the motor's. Oil burners also include combustion-proving devices to prevent out-of-control combustion - Primary Control; Safety Control; Cad Cell Control; Master Control; Fire-Eye Control are all common names for the 'combustion safety control'.

Fuel is injected into the combustion chamber by a spray nozzle.

The nozzles are usually supplied with high pressure oil. Because erosion from friction with the oil, and possible blockage due to lumps in it, they need replacement when worn. Fuel nozzles are usually rated in fuel volume flow per unit time e.g. USGal/h (U.S. Gallons per hour).

A fuel nozzle is characterized by three features:

Alternatively fuel may be passed over a tiny fed with compressed air. This arrangement is referred to as Babington atomiser/nozzle, named after its inventor Robert Babington. As the oil flows over the nozzle, the fuel needn't be under any great pressure. If the pump can handle such the oil may even contain lumps such as scraps of food. Because it is only compressed air that passes through the orifice hole, such nozzles do not suffer much from erosion.

A gear pump of two parts:

This pumps the oil in and increases the pressure in the nozzles to 15 bar maximum (217.5 psi). Usually a gerotor of the sickle type is used. Gear pumps are used frequently in oil burners because of their simplicity, stability and low price.

To set the heat output of the burner, the rate of fuel delivery via the nozzle must be adjustable. This is often achieved by an adjustable pressure relief valve between the pump and the nozzle. When the set pressure is reached (usually 100psi), this valve opens and allows excess oil to flow through a bypass back to the fuel tank or the pump suction side.

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Wikipedia