Maintenance
At least once every six months, check for proper operation by following
the preventative maintenance steps outlined below. These steps
should not be performed while the actuator is in service. If an internal
problem is suspected with the actuator, refer to the Disassembly and
Reassembly section.
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WARNING: To avoid serious injury, the following steps should
only be performed with the air supply or positioner input
disconnected.
1. When disconnecting air supply, observe actuator for correct fail-
safe action.
2. Examine the actuator for damage caused by corrosive fumes and
process drippings.
3. Clean the actuator and repaint any areas of severe oxidation.
4. If possible, stroke the actuator and check for smooth, full-stroke
operation.
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WARNING: To avoid serious injury, keep hands, hair and
clothing away from all moving parts while operating the
actuator.
5. Make sure positioner mounting bolts, linkage and stem clamp are
fastened securely.
6. Ensure all accessories, brackets and associated bolting are fastened
securely.
7. Check rubber bellows for wear.
8. Spray soap solution around the base and top of the cylinder, the
adjusting screw and the lower actuator stem bushing to check for
air leaks through the O-rings and gasket.
9. Clean any dirt or foreign material from the actuator stem.
10. If an air filter is supplied, isolate the air filter, then check and replace
cartridge as necessary.
Disassembly and Reassembly
Disassembling the Actuator
Refer to Figures 1 through 4 to disassemble the cylinder actuator.
1. Shut off air supply. If actuator is installed on a Flowserve valve,
remove the valve per the appropriate installation operation,
maintenance instructions.
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WARNING: To avoid serious injury, depressurize the line to
atmospheric pressure and drain all fluids before working on
the actuator.
2. Disconnect all tubing. Remove stem clamp and stem bellows from
the actuator stem.
3. Relieve spring compression by completely removing the adjusting
screw. Remove adjusting screw gasket from adjusting screw.
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WARNING: To avoid serious personal injury, relieve the
spring compression before further disassembly. The
cylinder end cap may fly off the yoke when removing the
cylinder tie-rod nuts.
4. Remove the four self-locking tie rod nuts by unscrewing in an
alternating pattern. Remove the cylinder end cap.
5. Lift the cylinder off the yoke and piston. If excessive O-ring resis-
tance is felt, use a rubber mallet to gently tap around the cylinder
perimeter.
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WARNING: To avoid serious personal injury, do not use
air pressure to remove the cylinder. The cylinder may fly
off the yoke.
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CAUTION: When removing the actuator stem lock nut,
do not hold the actuator stem with a pipe wrench as the
sealing surface may be damaged; instead, use a wrench
on the flats of the actuator stem.
6. For air-to-retract configurations, remove the spring(s) and spring
button for cleaning and inspection (see Figures 1, 3 and 4). Remove
the actuator stem locknut by holding the flats on the actuator stem
and slide the piston and stem spacer off the actuator stem. The
spring guide should be removed when using dual or heavy-duty
spring designs.
NOTE:
The dual spring configuration (Figure 3) has two springs,
one inside the other. Remove both springs during this step.
Valtek VL-C Spring Cylinder Linear Actuators FCD VLAIM054-01 – 06/13
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