Flowserve LPS Pneumatic Heavy-Duty Actuator Series - Manual (Page 23)

23
LPS Series Heavy-Duty Actuators FCD LFENIM0001-02-AQ – 5/15
flowserve.com
Perform the following steps:
4.3.1 If necessary, feed the pneumatic cylinder from the port on the head flange (19) at minimum necessary
pressure to facilitate the movement of the Scotch yoke and assure the total retraction of the piston rod (20).
In this way the spring is fully extended. Unscrew and remove the travel stop of the pneumatic cylinder. For
removing the stop, refer to the indications given in paragraph 2.3.
4.3.2 Remove at least two of the tie rods (31) positioned on the upper part of the cylinder by unscrewing the nuts
on the sides of the end flange and of the head flange (or unscrewing the tie rods from the head flange if
threaded into the flange.) This operation provides two free holes to be used for lifting the end flange (27).
Screw two male eyebolts in these two holes and connect the end flange to a lifting system. Care should be
taken to choose a lifting system suitable for the weight of the cylinder. Refer to the weight table shown in
Figure 29. Remove all other tie rods (31), following the same procedure described herein. Then remove the
end flange (27) from the tube (30).
4.3.3 Finally, remove the tube (22). Take care not to scratch or dent the honed and plated inner surface of the tube.
Remove the O-rings (28) from the flange; remove the O-ring of the piston (33) and finally the guide tapes
(23) from the piston. Clean all surfaces of piston and flanges in contact with these components with rag
and solvent. Brush the O-ring grooves with a light oil film and install the new O-rings. Spread a thin layer
of grease on the bottom of the guide tape grooves and install the new guide tapes (23). Clean the internal
surface of the tube (30) and lubricate with a protective oil film.
4.3.4 Reassemble the parts of the cylinder with the reverse procedure as described from points 4.3.2 to 4.3.5. The
tie rods should be tightened using a torque wrench, alternating between opposite holes, applying a torque
according to Table 3 or Table 4 included in Chapter 7. Readjust the stops as instructed in paragraph 2.3.
4.4 Scotch Yoke Housing Maintenance
Standard maintenance of the Scotch yoke housing may take place in the field, without the need to disassemble the
spring container or the pneumatic cylinder. Perform the following steps. The reference drawings are Figures 26 and 27.
a WARNING: Ensure that the pneumatic connection ports of the cylinder are disconnected. Also make sure that all
pneumatic supplies to the control unit and all power supplies are disconnected. Finally, make sure that the actuator
is in fail position.
Figure 26: Exploded View of Housing Figure 27: Exploded View of Assembling Kit