6 N1 70 en
7
3.4.1
N1_E_C actuator spring -to-close
direction
Install the actuator on the valve with the spring return position
(fail safe) and the valve in the closed position, see Fig. 5. The
cylinder must be de-pressurized and the air ports open. Adjust
the closed-position setting using the stop screw (42a) on
center block. The open-position setting is adjusted with stop
screw (42b) on the center block while the actuator is pressur-
ized and the piston is at the rear end of the cylinder.
Fig. 7
N1_E_C actuator
3.4.2
N1_E_A actuator spring -to-open
direction
Install the actuator on the valve with the spring return position
(fail safe) and the valve in the open position, see Fig. 6. The cyl-
inder must be de-pressurized and the air ports open. Adjust
the open-position setting using the stop screw (42b) on center
block. The closed-position setting is adjusted with stop screw
(42a) on the center block while the actuator is pressurized and
the piston is at the rear end of the cylinder..
Fig. 8
N1_E_A actuator
3.4.3
Demounting the actuator from the
valve
The actuator must be de-pressurized and the supply air dis-
connected. Unscrew the actuator-side screws of
the bracket and pull the actuator off the valve shaft. This is
best done lifting the actuator from lifting lugs by crane.
Note the mutual positioning of the valve and the actuator
to ensure correct functioning after reassembly.
4
MAINTENANCE
4.1
Maintenance general
Although Metso’s Neles actuators are designed to work
under severe conditions, proper preventative maintenance
Can significantly help to prevent unplanned downtime and
in real terms reduce the total cost of ownership. Metso rec-
ommends inspecting the actuators at least every five (5)
years. The inspection and maintenance interval depend on
the actual application and process condition. The inspec-
tion and maintenance intervals can be specified together
with your local Metso experts.
During this periodic inspection the parts detailed in the
Spare Part Set should be replaced. Time in storage should
be included in the inspection interval.
If maintenance assistance is required, please contact your
local Metso office. The part numbers in parentheses () in the
text refer to the exploded view and to the parts list in Sec-
tion 8, unless otherwise stated.
This procedure is applicable with the understanding that all
pneumatic pressure has been removed from the actuator.
Remove all piping and mounted accessories that will inter-
fere with the module that are to be worked on.
When removing seals from seal grooves; use a commercial
seal removing tool or a small screwdriver with sharp corners
rounded off.
Use a non-hardening thread sealant on all pipe threads.
All parts should be thoroughly inspected for excessive wear,
stress cracking and pitting. Attention should be directed to
threads, sealing surfaces and areas that will subjected to
sliding and rotating motion.
Actuator parts that reflect any of the above listed character-
istics should be replaced with new parts.
Metso recommends that disassembly of the actuator mod-
ules should be done in a clean area on a workbench.
After reassembly, the actuator needs to be stroke for several
times to ensure the desired function and safety.
If you remove the stop screw, adjust the limits after lubrica-
tion or grease filling!
Before doing maintenance, check actuator for leakage at
inlet, outlet and cover.
CAUTION:
Depressurise the actuator before starting demount-
ing!
CAUTION:
Observe the safety precautions mentioned in Section
1.7 before maintenance!
CAUTION:
Apply the thread sealant as per the manufacturer’s
instructions.
Summary of Contents for Neles N1 Series
Page 35: ...6 N1 70 en 35 ...
