Flowserve Valtek VL-ES Actuators - Manual (Page 8)

Valtek VL-ES Actuators FCD VLENIM0114-00 – 09/06

5.5 Insert the piston assembly into the yoke and cylinder. A threaded hole in the piston stem has been
provided as a lifting point. Generously lubricate the piston quad seal and install into the piston.
The grease should fill the valley between each of the quad seal lobes. Install the protective rubber
bellows on the actuator stem.
5.6 Lubricate the inside of the cylinder with a light coat of grease. Install the cylinder onto the yoke and
piston assembly. Use a soft mallet to gently tap the cylinder into place.
NOTE: Care must be taken as the cylinder and top cap are installed or the O-rings and quad seal can
be pinched. This will cause damage to the seals, which must then be replaced. Used quad seals will
swell somewhat due the effects of the lubricant and new seals should be used whenever the actuator is
reassembled.
5.7 Install the tie rods into the yoke using a removable thread-locker (Blue ® 266 thread locking
compound or equivalent). Using two nuts, jammed together, on the top threads of the tie rod will
make installing these rods easier. Remove any nuts used to screw the rods into the yoke.
5.8 Install the end cap onto the piston stem and the cylinder. Take care to line up the air holes on both
the yoke and the end cap.
WARNING: Damaged tie rods can fail, causing injury, property damage or death. Damaged tie rods
should be replaced. Do not use vice grips or similar devices which can leave scores and dents in the
surface of the tie rod. Chipped paint should be repainted.
WARNING: Tie rods must be fully threaded into the yoke. The tie rod must be flush, or extend
slightly beyond the bottom of the yoke.
5.9 Install and tighten the tie rod lock nuts. Then loosen the lock nuts by one turn.
5.10 Using the minimum air supply required, stroke the actuator three times. This provides alignment
between the upper and lower stem bushings.
5.11 Tighten the tie rod nuts using Table III to obtain the proper torque values.
Table III: Tie Rod Torque Values
Cylinder Size ft-lb Nm
100, 150 & 200 150 203
300 & 400 210 285
5.12 For ATO, fail closed actuators, lubricate the thrust washer on both sides with a calcium complex
grease and install both the spring guide and thrust washer.
5.13 Set the spring-can onto the cylinder assembly. Using appropriate anti-seize compound, install
two opposing spring-can bolts and lock washers, tightening half a turn at a time to bring the
spring-can down evenly onto the cylinder. Install and torque the remaining spring-can bolts and
lock washers, again using appropriate anti-seize compound.
5.14 For ATC, fail open actuators, stroke the actuator open using the low pressure air. Lubricate the
thrust washer with a calcium complex grease on both sides. Install the collar, thrust washer and
half rings. The half rings are slightly bent to keep them locked into place. They will need to be
gently tapped into place to squeeze them into the groove. Slowly release the air from the cylinder,
locking the half rings into place.
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