Emerson Fisher 667NS2 Instruction Manual page 19

Instruction Manual
D103472X012
Note
Do not use lubricant on these cap screws and nuts. Fasteners must be clean and dry.
6. Install the upper diaphragm casing (key 104), and secure with the cap screws, washers, and nuts (keys 119, 145,
and 120) 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 ft•lbf).
7. Tighten the remaining hex nuts in a clockwise, criss‐cross pattern to 13 NSm (10 ft•lbf).
8. Repeat this procedure by tightening four hex nuts, diametrically opposed and 90 degrees apart, to a torque of 27
NSm (20 ft•lbf).
9. Tighten the remaining hex nuts in a clockwise, criss‐cross pattern to 27 NSm (20 ft•lbf).
10. After the last hex nut is tightened to 27 NSm (20 ft•lbf), all the hex nuts should be tightened again to 27 NSm (20
ft•lbf) in a circular pattern around the bolt circle.
11. Once completed, no more tightening is recommended.
12. Lift the spring (key 110) and spring seat (key 121) into position. Apply Nuclear Grade anti-sieze lubricant (key 27) to
the threads of the actuator stem (key 125) and to the surface of the spring adjusting screw (key 127) that contacts
the spring seat. These locations are indicated on the assembly drawing in figure 4. Thread the spring adjusting
screw on the actuator stem so that it matches the position recorded during disassembly. Continue to rotate the
spring adjusting screw until a set of threaded holes line up with the flat on the actuator stem. Apply Loctite 242 (key
185) to the cap screws (key 194) and thread them into the spring adjusting screw. Tighten the cap screws to 23
NSm (17 ft•lbf) after adjustment of the bench set.
13. Thread the stem hex nuts (key 115) onto the valve plug stem.
14. Mount the actuator on the valve body, and make up the stem connection by following the procedures in the
Mounting the Actuator on the Valve section.
Note
For actuators with yoke spacers (key 209), when lifting the yoke spacer and actuator (figure 5) together, follow the previous
instructions for lifting a valve/actuator assembly.
Size 80 Actuators
Key number references are shown in figure 7.
1. Install qty-2 O-rings (key 117) into the grooves in the inner diameter of the seal bushing (key 116). Install qty-1
O-ring (key 118) into the groove in the outer diameter of the seal bushing (key 116). Lubricate the O-rings and fill
the seal bushing with NyoGel 718B (key 149), as appropriate to the installation. Place the seal bushing and O-rings
into the yoke/casing assembly (key 109), and install the snap ring (key 124).
2. To aid in assembling the actuator stem (key 125) and associated parts (keys 108, 105, 107, 132A, and 132B), attach
the stem connector assembly (key 103) onto the actuator stem, and grip the stem connector in a vise.
3. Coat the threads of the middle of the actuator stem (key 125) and the seating side of the hex jam nuts (keys 132A
and 132B) with Nuclear Grade anti-seize lubricant (key 27). Slide the lower diaphragm plate (key 108), the
diaphragm (key 105), and the upper diaphragm plate (key 107) onto the actuator stem. Slide the first hex nut (key
132A) onto the stem, tighten the hex nut to 650 NSm (480 ft•lbf), slide the second hex nut (key 132B) onto the
stem, and tighten it to 407 NSm (300 ft•lbf). Remove the subassembly from the vise, and remove the stem
connector assembly (key 103) from this subassembly.
4. Slide the shorter end of the actuator stem through the seal bushing and the O‐rings (key 117), and align the
diaphragm cap screw holes with the lower diaphragm casing flange cap screw holes.
667NS2 Actuator
March 2022
19