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Chapter 2
D. Oil System
EV Series burners use compressed air for atomization.
Atomizing air is independent of combustion air. The system
is supplied with a separate compressor module for mounting
near the burner.
3-Way Solenoid Valve
Metered oil enters the common port of the 3-way solenoid
valve. During shutdown, pre- and post-purge, the valve is de-
energized (N.C. port closed) and all metered fuel oil returns
to the storage tank. When the valve is energized, metered oil
is directed to the nozzle through the N.C. port.
Nozzle Assembly
The nozzle assembly consists of four main parts: body,
compression spring, swirler, and tip. The swirler is held
against the nozzle tip by the compression spring. The nozzle
body has inlet ports for air and oil lines. Metered fuel oil
enters the nozzle body and flows through a tube to the swirler.
Oil is forced from the core of the swirler to the side ports
where it meets with the atomizing air. Atomizing air enters
and passes through the nozzle body to grooves in the swirler,
where it mixes with fuel oil. Air/oil passes through grooves
and out of the nozzle orifice in a cone of atomized oil. Proper
velocity and angle of the fine spray ensures good mixing with
2-2
the combustion air, providing quiet starts and excellent
combustion efficiency. During pre- and post-purge, the
nozzle tip is purged with air. This prevents afterdrip or baked-
on residue
Oil Strainer
Prevents foreign matter from entering the burner oil system.
Atomizing Air Proving Switch
Pressure actuated switch contacts close when sufficient
atomizing air pressure is present. The oil valve will not open
unless switch contacts are closed.
Oil Metering
Fuel oil under nominal pressure in the circulating loop flows
to the adjustable positive displacement (volumetric metering
unit). Oil metering is accomplished by changing the piston
stroke by means of an eccentric shaft and pin assembly. The
pistons reciprocate in a rotor assembly, turning in a hardened
steel sleeve having oil inlet and discharge slots. During each
revolution the pistons go through the following cycle:
A
B
Inlet Cycle. The piston is at the bottom dead center po-
sition. At this position, the cavity between the top of the
piston and the outside diameter of the rotor fills with oil.
SWIRLER
NOZZLE BODY
POSITIONING COLLAR
OIL NOZZLE ASSEMBLY
Profire EV/LNEV Burner
D
C
E
F
NOZZLE TIP
8
SPRING
G
750-364
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