December 2020
Installation, Operation and Maintenance Manual
MAN 608 Rev. 5
Maintenance
32
Section 5: Maintenance
5.2.1
Replacement of Cylinder Seals
1.
Unscrew the cover of the adjustment screw (23).
2.
Measure the distance of the stop screw (20) with reference to the end flange (22)
surface, so as to be able to easily restore the setting of the actuator mechanical
stop, once the maintenance procedures have been completed.
3.
Unscrew the stop screw (20) by turning it anticlockwise with an Allen wrench until
the screw is completely with drawn inside the end flange threaded hole.
4.
Unscrew the nuts (25) from the tie rods (18): they must be gradually unscrewed all
at the same time.
5.
Slide off the end flange (22) and the tube (21).
6.
If the actuator control unit requires the cylinder chamber head flange side to be
also filled with gas, and the piston rod seal ring (47) to be replaced, remove the
screw (34) and the cover (33). Unscrew the piston rod (17) threaded end from the
adaptor bush (31) of the guide block (14). Slide off the piston rod (17) from the
head flange (49).
7.
Disassemble the head flange (49) from the mechanism housing (8) by removing the
screws (7) only if the gaskets (44) and (46) have 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 LCX 2/32 if seals are in NBR/Viton or Neoprene rubber,
or 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.
Assemble the new O-ring into its groove and lubricate it with a protective oil film.
1.
Replace the O-ring (48) of the head flange (49).
2.
Replace the O-ring (50) of the end flange (22).
To replace the piston rod seal rings (47) proceed as follows:
1.
Remove the existing Teflon seal ring (51) with its O-ring from their groove.
2.
Clean the groove carefully and lubricate it with a protective oil film.
3.
Assemble the new O-ring into its groove and lubricate it with a protective oil film.
4.
Assemble the new Teflon seal ring (47) into the flange groove, inside its rubber
O-ring, by bending it : take care that the bending radius is as large as possible
to avoid damaged the seal. Then enlarge the seal ring with your fingers so as to
restore its round shape: pay attention not to utilise any tools, which can damage
the seal ring.
To replace the piston seal ring (53) proceed as follows:
1.
Remove the existing Teflon seal ring (47) with its O-ring from their groove.
2.
Clean the groove carefully and lubricate it with a protective oil film.
3.
Assemble the new O-ring into its groove and lubricate it with a protective oil film.
4.
Assemble the new Teflon seal ring (47) on its rubber O-ring by introducing one
side of it into the groove, then enlarge it with your fingers so as to fit it into the
groove: take care to enlarge it uniformly without any tools which could possibly
damage it. The elastic memory of the kind of Teflon the seal ring is made of allows
the ring to shrink back to its previous dimension after a short time.
