Emerson Fisher 667NS2 Instruction Manual page 20

667NS2 Actuator
March 2022
5. Lubricate the guide bushing (key 133) with NyoGel 718B (key 149), as appropriate to the installation. Lubricate the
bearing race and bearing (keys 129 and 130) with NyoGel 718B (key 149).
6. Position the spring (key 110), the spring seat (key 121), the lubricated bearing race (key 129) and bearing (key 130),
and the lubricated guide bushing (key 133) on top of the diaphragm plate as shown in figure 7.
7. If the spring casing assembly (key 131) has been removed from the upper diaphragm casing, replace it and tighten
the cap screws, with Loctite 242 (key 185) applied to the threads and washers (keys 114 and 144), to 102 NSm (75
ft•lbf) torque. If the travel stops (key 134) have been removed from the upper diaphragm casing (key 104), apply
Loctite 242 (key 185) to the travel stop threads. Tighten them to the inside of the upper diaphragm casing to 102
NSm (75 ft•lbf). Lower the diaphragm casing and spring case assembly onto the diaphragm.
Note
When you replace actuator diaphragms in the field, take care to ensure the diaphragm casing bolts are tightened to the proper
load to prevent leakage, but not crush the material. Perform the following tightening sequence with a manual torque wrench for
size 80 actuators.
CAUTION
Overtightening the diaphragm casing cap screws and nuts can damage the diaphragm. Do not exceed the final torque
values for the appropriate diaphragm material. These final torque values can be found in table 6.
Note
Do not use lubricant on these cap screws and nuts. Fasteners must be clean and dry.
Table 6. Size 80 Casing Cap Screw Torque Values
DIAPHRAGM MATERIAL
EPDM / Meta-Aramid
Nitrile, Silicone, FKM/Meta-Aramid
8. Insert the diaphragm casing cap screws, washers, and nuts (keys 119, 145, and 120) and tighten in the following
manner. The first four hex nuts tightened should be diametrically opposed and 90 degrees apart. Tighten these four
hex nuts to the initial torque value found in table 6 for the diaphragm material being used.
9. Tighten the remaining hex nuts in a clockwise, crisscross pattern to the initial torque value found in table 6 for the
diaphragm material being used.
10. Repeat this procedure by tightening four hex nuts, diametrically opposed and 90 degrees apart, to the final torque
value that is specified in table 6 for the diaphragm material being used.
11. Tighten the remaining hex nuts in a clockwise, crisscross pattern to the final torque value that is specified in table 6
for the diaphragm material being used.
12. After the last hex nut is tightened, complete another tightening sequence. Tighten in a circular pattern around the
bolt circle to the final torque value that is specified in table 6 for the diaphragm material being used.
13. Once completed, no more tightening is recommended.
14. Lubricate the spring adjusting screw (key 127) and the seating face of the jam nut (key 135) with Nuclear Grade
anti-seize lubricant (key 27). Thread the spring adjusting screw (key 127) into the hex jam nut (key 135) and spring
casing assembly (key 131) so that the spring adjusting screw matches the position recorded in step 4 of the
20
INITIAL TORQUE
NSm (ftSlbf)
25.5 (19)
25.5 (19)
Instruction Manual
D103472X012
FINAL TORQUE
NSm (ftSlbf)
51 (38)
51 (38)