Size 80 Actuators - Emerson Fisher 667NS Instruction Manual

667NS Actuator
June 2018
9. Tighten the remaining hex nuts in a clockwise, criss‐cross pattern to 27 NSm (20 lbfSft).
10. After the last hex nut is tightened to 27 NSm (20 lbfSft), all of the hex nuts should be tightened again to 27 NSm (20
lbfSft) in a circular pattern around the bolt circle.
11. Once completed, no more tightening is recommended.
Table 6. Size 80 Casing Cap Screw Torque Values
DIAPHRAGM MATERIAL
EPDM / Meta-Aramid
Nitrile, Silicone, FKM/Meta-Aramid
12. Lift the spring (key 18) and spring seat (key 19) into position. Apply lithium grease to the threads of the actuator
stem and to the surface of the spring adjustor (key 74) that contacts the spring seat. These locations are indicated
on the assembly drawing in figures 2 and 3. Thread the spring adjustor on the actuator stem so that it matches the
position recorded during disassembly. Thread the spring adjustor jam nut (key 102) up against the spring adjustor,
and tighten securely.
13. Thread the stem hex nuts (keys 69 and 75) on the valve plug stem, and place the travel indicator (key 34) on these
nuts with the cupped portion pointing towards the valve body.
14. Mount the actuator on the valve body, and make up the stem connection by following the procedures in the
Actuator Mounting section.

Size 80 Actuators

Key number references are shown in figure 4.
1. Coat a new gasket (key 96) with lithium grease (key 99) or high‐temperature, radiation‐resistant, polyphenyl ether
grease (key 100), as appropriate to the installation, and place the gasket on the yoke (key 73). Position the lower
diaphragm casing (key 64) on the yoke. Insert and tighten the cap screws (key 30) to 102 NSm (75 lbfSft) torque.
2. Insert new O‐rings (keys 8 and 9) into the seal bushing (key 7). Lubricate the O‐rings, and fill the seal bushing with
lithium grease (key 99) or high‐temperature, radiation‐resistant, polyphenyl ether grease (key 100) or equivalent,
as appropriate to the installation. Place the seal bushing and O‐rings into the yoke, and install the snap ring (key 72).
3. To aid in assembling the actuator stem (key 93) and associated parts (keys 94, 4, 3, and 71), attach the stem
connector assembly (key 31) onto the actuator stem, and grip the stem connector in a vise.
4. Slide the lower diaphragm plate (key 71), the diaphragm (key 3), and the upper diaphragm plate (key 4) onto the
actuator stem. Slide the first hex nut (key 94) onto the stem, tighten the hex nut to 542 NSm (400 lbfSft), slide the
second hex nut onto the stem, and tighten it securely against the first hex nut. Remove the subassembly from the
vise, and remove the stem connector assembly (key 31) from this subassembly.
5. Slide the shorter end of the actuator stem through the seal bushing and the O‐rings (key 8), and align the
diaphragm cap screw holes with the lower diaphragm case cap screw holes.
6. Lubricate the guide bushing (key 97) with lithium grease or high‐temperature, radiation‐resistant, polyphenyl ether
grease, as appropriate to the installation. Lubricate the bearing race and bearing (keys 88 and 89) with lithium
grease.
7. Position the spring (key 18), the spring seat (key 19), the lubricated guide bushing (key 97), and the lubricated
bearing race and bearing on top of the diaphragm plate as shown in figure 4.
8. If the spring case assembly (key 92) has been removed from the upper diaphragm casing, replace it, making sure
the vent holes in the diaphragm casing and in the spring case are aligned, and tighten the cap screws (key 30) to
102 NSm (75 lbfSft) torque. 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.
16
INITIAL TORQUE
NSm (lbfSft)
41 (30)
34 (25)
Instruction Manual
D102603X012
FINAL TORQUE
NSm (lbfSft)
82$13 (60$10)
68 (50)