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5.2 Extraordinary maintenance
If there are leaks in the pneumatic cylinder or a
malfunction in the mechanical components, or
in case of scheduled preventive maintenance,
the actuator must be disassembled and
seals must be replaced with reference to
the following general sectional drawing and
adopting the following procedures.
5.2.1 Replacement of cylinder seals
(refertosectional drawing, figure 20)
IMPORTANT
Before carrying out any maintenance operation, it
is necessary to close the pneumatic feed line and
exhaust the pressure from the actuator and from
the control unit, to ensure safety of maintenance
staff.
Installation, commissioning and maintenance and
repair works should be carried out by qualified
staff.
Before carrying out any operation, cut power off
from the electrical line.
Replacement of cylinder seals
1. Measure the protrusion of the stop screw
(30) with reference to the end flange (4)
surface, so as to be able to easily restore
the setting of the actuator mechanical stop,
once the maintenance procedures have
been completed.
2. Loosen the lock nut (10) and unscrew the
stop screw (30) together with the nut (10),
the washer (28) and the sealing washer (17).
3. Unscrew the nuts (25) from the tie rod (14)
from the side of the end flange: they must
be gradually unscrewed all at the same
time.
4. Slide off the end flange (4) and the tube (13).
The spacer tube (33) must remain in place.
Take care not to damage the plane surfaces
of the tube ends.
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 by recommended oil (SHELL
Omala S4 WE 320 or equivalent). If the O-ring
must be replaced, remove the existing one
from its groove, clean the groove carefully and
lubricate it with protective oil film. Assemble
the new O-ring into its groove and lubricate it
with a protective oil film.
1. Replace the O-ring (24) and the piston guide
sliding ring (20).
2. Remove the existing gasket (7) from its seat
in the end flange (4).
3. Carefully clean the seat of the gasket in the
end flange (4) and the plane surface, of the
tube end (13), which is in contact with the
gasket (7).
4. Carefully clean the ends of the cylinder
tube (13) and of the spacer tube (33), which
must fit together, to remove any trace of the
sealant which assures tightness.
5. Remove the sealing washer (17) from the
travel stop screw (30). Carefully clean and
lubricate the travel stop screw thread and
the surface of the end flange area, where
the sealing washer is.
6. Screw the new sealing washer onto the travel
stop until it is in contact with the nut (10).
7. Assemble the washer (28) onto the sealing
washer (17).
Reassemble
1. Assemble the new cylinder gasket (7) on its
seat on the end flange (4).
2. Carefully clean the inside of the tube
(13) and check that the entire surface,
particularly that of the bevels, is not
damaged. Lubricate the inside surface of
the tube and the bevels at the ends.
3. Spread some sealant LOCTITE 510, or
equivalent, on the cylinder tube end (13),
which is connected to the spacer tube (33).
4. Slide the cylinder tube (13) onto the piston
taking care not to damage the piston O-ring
(24).
5. Assemble the end flange (4) centring it
on the tube (13). Assemble the nuts (25)
onto the tie rod (14). Tighten the nuts to
the recommended torque (see table),
alternating between opposite corners.
Screw the travel 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).
6. Check that the sealing washer (17) and
the washer (28) are in contact with the end
flange surface.
7. Tighten the lock nut (10).
RPS SPRING RETURN PNEUMATIC ACTUATOR
INSTALLATION, OPERATION AND MAINTENANCE MANUAL
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