Installation, Operation and Maintenance Manual
MAN 689 Rev. 6
June 2021
33
Maintenance
Section 5: Maintenance
If the O-ring (17) has to be replaced, measure the protrusion of the stop screw (11) with
reference to the end flange (13) surface, so as to be able to easily restore the setting of the
actuator mechanical stop in the correct previous valve position, once the maintenance
procedures have been completed.
1.
Loosen the stop setting screw cover (14) and unscrew the stop screw (11).
2.
Remove the O-ring (17) from the stop screw (11). 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 stop setting screw
cover (14).
4.
Screw the stop screw into the threaded hole of the end flange until it reaches its
original position (the same protrusion with reference to the flange surface).
5.
Check that the O-ring (17) is inside the groove into the end flange and in contact
with the groove bottom surface.
5.2.2.2
Cylinder reassembling
1.
Assemble the new gasket (item 25-Figure21) after cleaning the surfaces of
pneumatic cylinder end flange (item 22-Figure21) and head flange (item 2) which
are in contact.
2.
Assemble the head flange and tighten the screws (item 26-Figure21) to the
recommended torque.
3.
Clean and lubricate the piston rod (item 6) surface, particularly that of the bevel,
with a protective grease film and introduce it into the head flange hole, taking care
not to damage the Teflon seal ring (item 4): the piston rod bevel has to enlarge
smoothly the seal ring.
4.
Carefully clean the inside of the tube (item 12) and check that the entire surface,
particularly that of the bevels, is not damaged. Lubricate with protective grease
film the tube inside surface and the bevels at the ends.
5.
Slide the tube onto the piston taking care not to damaged the Teflon seal ring
(item 9): the tube bevel has to smoothly compress the seal ring. Take care also not
to damage the head flange O-ring (item 3).
6.
Assemble the end flange (item 13) by centering it on the inside diameter of the
tube, taking care not to damage the O-ring (item 3).
7.
Assemble the washers (item 15) and the nuts (item 16) onto the tie rods
(item 10). Tighten the nuts to the recommended torque, alternating between
opposite corners.
NOTICE
After maintenance operations carry out a few actuator operations (5 - 10) to check that
its movement is regular, that there is no air leakage through the seals and to to eliminate
any oil residues in the air circuit, deriving from the lubrication of the seals during the
replacement phase.
