24
Start-up
Return Nozzle Rod RDG 1250
Function description
The return nozzle rod RDG 1250 is for
return nozzle without integrated needle
valve and comes with M14 screw con-
nection (for example Sonic DZ 1000,
CBM M14).The locking mechanism
consisted of a slider with seal ring (Pos.
2 and 6) in the forward flow section and
a needle valve (Pos. 5) in the return
flow section, using the sliding rod con-
trol by a hydraulic control-piston system
located at the back of the nozzle rod.
The opening pressure of RDG 1250 is
about 3 bar in forward flow section or 13
to 20 bar in return flow section. When
the solenoid valves are open, the pres-
sure from the oil would retract the con-
trol-piston via the pressure channel
(Pos. 7) and then push open the slider .
Both the control-piston and sliding rod
with needle valve would remain open as
long as there is an existing oil pressure.
The same oil pressure would keep the
slider open. Under normal circum-
stances, both locking mechanisms
would open at the same time. The oil in
the forward flow section would exit
through the nozzle head to be mixed
with the air for combustion. The remai-
ning oil would be redirected through the
return holes of the nozzle back into the
return flow section of the nozzle rod
assembly. When it is not in operation,
the swirl plate in the nozzle head blocks
the return flow.The return oil flow rate
can be adjusted accordingly using a
pressure control valve If the pump pres-
sure is too low (<20 bar), thereby pre-
venting the control needle from opening
all the way, variations in throughput are
to be expected as the needle position
will affect the return oil flow.
Control-piston opening distance H is set
in the factory at 9mm. Any adjustment
at installation site is not necessary.
1
5
3
6
4
7
2
+
The Control piston
opens at ca. 13 bar;
Fully open at 20 bar.
Close at 10 bar.
1 Return Nozzle
2 Slider
3 Spring (Forward)
4 Sliding rod
5 Needle valve
6 Seal ring (Forward)
7 Pressure channel
Distance H = 9 mm
Fo
rward
V
a
lv
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