30
Return Nozzle Rod DG 75
Functional description
Pre-flushing
The oil delivered by the burner pump
will enter the feed pipe (Item 2) via the
connection block (Item 1). Then it flows
through the feed pipe to the closing
taper plug of the regulating piston (Item
4). The plug is permanently pressed
against the nozzle head (Item 7) by a
cylindrical pressure spring (Item 5) so
that the feed pipe is kept in closed posi-
tion. At the same time, pressure is app-
lied to the connecting rod (Item 8) by a
spring (Item 6) so that the valve needle
(Item 12) is pressed against the return
opening of the nozzle head (Item 7),
thus keeping the latter in closed posi-
tion.
In this position the oil may only enter the
return pipe (Item 9) through the opened
flushing hole (Item 13) and will return to
the gas-air separator and finally to the
fuel tank. This will give an effective flush
up to the nozzle.
Operating function
After the air pre-flushing period, an
electromagnet will be operated and
apply a tensile force via an arm (Item
10) to the connecting rod (Item 8). As
the valve needle and the regulating
piston are connected to one another,
the feed pipe and return pipe will be
opened at the same time so that the oil
can flow to the nozzle through the hole
of the nozzle head.
At the same time the regulating piston
(Item 4) will shut off the flushing hole
(Item 13) to the return pipe. This causes
the oil to be forced to the nozzle with
part of the oil flowing back through the
return opening of the nozzle (Item 11)
and the nozzle rod. The return oil flow
rate is controlled in dependence of the
pressure by means of an output pres-
sure regulating valve in accordance with
the required load.
When the burner is stopped the sole-
noid actuator will be turned off so that
through the action of the pressure
springs in the feed and return pipes the
valve needle and the regulating piston
will shut off the return pipe and feed
pipe, respectively.
For the adjustment of the transmission
arm (Item 10) it should be ensured that
the solenoid actuator (Item 14) is de-
energized. Care should also be taken to
avoid any mechanical loads. Pull out
the anchor (Item 15) to the stop, uns-
crew the lock nut (Item 16) and turn the
anchor (Item 15). When the solenoid
actuator is de-energized there should
be a noticeable backlash in the trans-
mission linkage. When operated electri-
cally, the solenoid actuator should
produce and audible noise when
making contact with the mechanical
stop. The valve needle (Item 12) must
be operated over its full travel of 4 mm.
Tighten the lock nut (Item 16).
Lift
Lift
Flushing nozzle rod DG-75 (complete)
Description of items
1. Connection block
2. Feed pipe
3. Rod block
4. Regulating piston
5. Feed pressure spring
6. Return pressure spring
7. Nozzle head
8. Connecting rod
9. Return pipe
10. Arm
11. Return feed
12. Valve needle
13. Flushing hole
Transmission arm
Mount for arm
Feed Return