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Installation, Operation and Maintenance Manual
MAN 564 Rev. 6
June 2020
Maintenance
Section 5: Maintenance
!
WARNING
Before executing any maintenance operation, it is necessary to intercept the supply line
and discharge pressure from the cylinder of the actuator.
If the actuator can be operated, it is essential to take it to fail safe position, otherwise the
actuator should be disassembled from the valve and follow these steps:
1)
Remove the nuts (16) and the washers (24) from the tie rods (18) at the end
flange (22) side.
2)
Slide off the end flange (22) and the tube (19).
3)
Remove the screw (2) and the cover (1).
4)
Unscrew the piston rod (20) threaded end from the adaptor bush (30) of guide
block (14).
5)
Slide off the piston rod (20) from the head flange (17).
6)
Disassemble the head flange (17) from the mechanism housing (8) by removing
the screw (15) only if the gasket (36) has to be replaced because damaged.
Seals replacement
Prior to reassemble check that the actuator components are in good conditions
and clean. Lubricate all the surfaces of the parts, which move in contact with other
components, by recommended grease (AGIP-ENI HTX-SIL if seals are in NBR/Viton or
Neoprene rubber, with Aeroshell Grease 7 if the seals are in Fluorosilicon rubber). If the
O-ring must be replaced, remove the existing one from its groove, clean the groove
carefully and lubricate it with protective grease film. Assemble the new O-ring into its
groove and lubricate it with a protective grease film.
1)
Replace the O-rings (39-40) of the head flange (17).
2)
Replace the O-ring (42) and the guide sliding ring (41) of the piston (21).
Replace the O-ring (40) of the end flange (22).
If the sealing washer (43) has to be replaced, measure the protrusion of the stop screw (26)
with reference to the end flange (22) surface, so as to be able to easily restore the setting
of the actuator mechanical stop in the closed valve position, once the maintenance
procedures have been completed.
1)
Loosen the lock nut (25) and unscrew the stop screw (26) until it is removed
together with the nut (25), the washer (44) and the sealing washer (43).
2)
Remove the sealing washer (43) from the stop screw (26). Carefully clean and
lubricate the stop screw thread and the surface of the end flange area, on which
the sealing washer works.
3)
Screw the new sealing onto the stop screw until it touches the nut (25).
