baltur GI 1000 DSPN-D, Инструкция по эксплуатации

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DESCRIPTION OF OPERATION WITH HEAVY OIL
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EE
0002900311)
Turn the main isolating switch “Q1” to on: the power indicator light will
come on, as will the auxiliary elements of the pump, filter, atomising
unit and regulating valve (.....N-D version only).
Turn the start/stop switch “S1” to on: power reaches the “LFL...”
control box at terminal “1” and the preheater regulation thermostats.
The voltage crosses the thermostat contacts and reaches the “KR1”
and “KR2” element contactor coils which come on and heat the fuel
contained in the preheaters.
The preheater minimum thermostats come on when the temperature
reaches the value to which they are set, thus turning on the control
box via the pressure switch line.
The cyclic relay control box carries out the ignition programme by
running the fan motor to effect pre-ventilation.
If the air pressure supplied by the fan is sufficient to trip the relative
pressure switch then the motor of the pump which pre-circulates
the hot air in the burner conduits starts immediately.
The oil flows from pump to preheater, passes through the latter,
heats up to the set temperature and exits via a filter where it then
reaches the atomising unit. The hot oil circulates in the atomising
unit without exiting the nozzle because the passageways towards
the nozzle (delivery) and from the nozzle (return) are closed. Clo -
sure is effected by means of the “closing cones” applied to the rod
extremities.
These “cones” are pressed against the seats by strong springs fitted
at the opposite end of the rods. The oil circulates and exits from
the atomising unit return via the sump where the TRU thermostat
is inserted. It then arrives at the return pressure regulator, passes
through it and reaches the pump return. From this, it is discharged
into the return . The above-described hot oil circuit is effected at a
pressure slightly higher (a few atmospheres higher) than the mini -
mum to which the return pressure regulator is set (10 - 12 bar).
This oil pre-ventilation stage lasts 22.5 seconds. This time can be
extended (in theory, indefinitely) because the design of the electrical
circuit does not allow the ignition programme to proceed until the
fuel in the nozzle return piping has reached the temperature to which
the TRU (Thermostat on Nozzle Return) is set.
This special design feature stops the fuel passing through the nozzle
until the fuel itself reaches at least the temperature to which the
TRU thermostat is set. The TRU thermostat usually trips within the
standard pre-ventilation time (37.5 seconds); if it does not, heavy
oil pre-ventilation and pre-circulation are extended until the TRU
trips. When the TRU trips (circulating oil hot enough) it allows the
control box to proceed with the ignition programme by switching on
the ignition transformer and then the gas pilot flame valves.
The high voltage between the burner electrode and its ground
causes the spark which ignites the gas/air mix. Flow is regulated
by the flow-rate regulator incorporated in one of the two pilot flame
valves. The flame is detected by the UV photocell.
!
If the UV photocell does not detect the flame then the burner
locks out. When more than one burner is operating in the com -
bustion chamber, you must make sure that the UV photocell
of one burner does not detect the flame of the other. This is
prevented by installing the photocell on a rotatable support
so that it can be positioned to avoid the above-described
interference.
Just 2.5 seconds after the ignition of the pilot flame, the control box
powers the magnet which, via a series of lever mechanisms, moves
the two nozzle fuel flow (delivery and return) interception rods.
The moving of these rods causes closure of the by-pass inside the
atomising unit; consequently, the in-pump pressure is brought to
the standard value of about 20 - 22 bar. The shifting of the two rods
from the closure seats now lets the fuel flow into the nozzle at a
pump-regulated pressure of 20 - 22 bar and exit the nozzle properly
atomised. The return pressure, which determines the flow in the
chamber, is adjusted by the return pressure regulator.
For ignition flow rate (minimum delivery) this value is about 10 - 12
bar. The atomised fuel which exits the nozzle mixes with the fan-fed
air and is ignited by the already-lit gas pilot flame.
After the magnet is switched on the pilot flame is switched off and
the burner is run at the modulation minimum.
Flow increase occurs automatically and continuously according to
the signals from the modulation probe: increase is effected by means
of a servomotor. The modulation motor controls a simultaneous
increase in the flow of both fuel and combustion air.
The increase in the flow of fuel is determined by the variable-profile
disk which, by rotating, causes greater compression of the return
pressure regulator spring and thus an increase in return pressure
corresponds to an increase in fuel flow.
An increase in fuel flow must correspond to an increase (of adequate
quantity) of combustion air. This condition is brought about during
the first adjustment by acting on the screws that vary the combustion
air adjuster control disk profile.
Fuel flow and, at the same time, combustion air flow, increase up
to maximum pressure (fuel pressure at return pressure regulator of
about 18 - 20 bar) if pressure at the pump is 20 - 22 bar.
Fuel and combustion air flow rates remain at maximum until boiler
temperature (pressure in the case of a steam boiler) nears the set
value and causes the modulation control motor to invert rotation.
The return movement of the modulation motor causes a reduction
in the flow of fuel and relative combustion air.
The modulation system reaches a position of equilibrium which
corresponds to a flow of fuel and relative combustion air equal to
the quantity of heat requested by the boiler.
With the burner working the in-boiler probe detects variations in
boiler load and automatically sends a signal to the modulation motor
to adjust the flow of fuel and relative combustion air accordingly.
If, even with just the minimum flow of fuel and combustion air, the
maximum temperature (or pressure in the case of a steam boiler)
is reached, the thermostat (pressure switch in the case of a steam
boiler) will shut down the burner completely.
Subsequently, the temperature (or pressure in the case of a steam
boiler) will drop back below the shutdown setting and the burner will
re-ignite as described above. Bear in mind that the possible flow
range, with good combustion, is approximately from 1 to 1/3 of the
max flow rate indicated on the ID plate.
Should the flame fail to appear within two seconds of the pilot fla -
me igniting, the control box places the unit in “lock-out” (complete
shutdown of burner with relative warning light).
To “reset” the control box press the appropriate reset button.
!
The air pressure switch must be adjusted on igniting
the burner as a function of the pressure value observed for
operation with the pilot flame.