Assembly; Size 40, 45, And 70 Actuators - Emerson Fisher 667NS Instruction Manual

Instruction Manual
D102603X012
12. Unbolt the lower diaphragm casing cap screws (key 30), and lift the lower diaphragm casing (key 64) and gasket
(key 96) off the actuator yoke.

Assembly

Size 40, 45, and 70 Actuators

Key number references are shown in figure 2 for size 40 and 45 actuators and in figure 3 for size 70 actuators.
1. Place the spring (key 18) into the yoke (key 73). Coat the gasket (key 70) 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 top of the yoke. Replace the yoke cap (key 239), and then place another lubricated gasket (key
70) on top of the yoke cap.
2. Attach the lower diaphragm casing (key 64) to the yoke cap with the cap screws (key 30). Tighten the cap screws to
41 NSm (30 lbfSft) of torque for the size 40 and 45 actuators, and 102 NSm (75 lbfSft) of torque for the size 70
actuators. Insert and evenly tighten the cap screws using a crisscross pattern.
3. Place the O‐rings (keys 8 and 9) in the seal bushing (key 7).
4. Lubricate the O‐rings, and fill the seal bushing with lithium grease (key 99) or high‐temperature, radiation‐resistant,
polyphenyl ether grease
(key 100) as appropriate to the installation, and reinstall the bushing in the top of the yoke. Secure with the snap
ring (key 72).
5. Assemble the actuator stem (key 144), the lower diaphragm plate (key 71), the diaphragm (key 3), the upper
diaphragm plate (key 4), and the diaphragm plate cap screw and spacer (keys 12 and 2). Tighten the cap screw to
the torque value indicated in table 3; then place this assembly in the actuator. Take care when pushing the actuator
stem through the seal bushing so that the threads do not damage the O‐rings.
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 40, 45, and 70 actuators.
CAUTION
Overtightening the diaphragm casing cap screws and nuts (keys 13 and 14) can damage the diaphragm. Do not exceed a
torque of 27 NSm (20 lbfSft) when performing the following tightening procedure.
Note
Do not use lubricant on these cap screws and nuts. Fasteners must be clean and dry.
6. Install the upper diaphragm casing (key 1), and secure with the cap screws and nuts (keys 13 and 14) in the
following manner. The first four hex nuts tightened should be diametrically opposed and 90 degrees apart. Tighten
these four hex nuts to 13 NSm (10 lbfSft).
7. Tighten the remaining hex nuts in a clockwise, criss‐cross pattern to 13 NSm (10 lbfSft).
8. Repeat this procedure by tightening four hex nuts, diametrically opposed and 90 degrees apart, to a torque of 27
NSm (20 lbfSft).
667NS Actuator
June 2018
15