Emerson Process Management FISHER 657 - Manual (Page 12)

Instruction Manual
D100306X012
657 Actuator (30-70 and 87)
December 2010
12
6. Position the upper diaphragm casing (key 1) on the diaphragm (key 2) and align the holes.
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 30‐70 and 87 actuators.
CAUTION
Over‐tightening the diaphragm casing cap screws and nuts (keys 22 and 23) can damage the diaphragm. Do not exceed 27
N
Sm (20 lbfSft) torque.
Note
Do not use lubricant on these bolts and nuts. Fasteners must be clean and dry.
7. Insert the cap screws (key 22), and tighten the hex nuts (key 23) 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 N Sm (10 lbfSft).
8. Tighten the remaining hex nuts in a clockwise, criss‐cross pattern to 13 N Sm (10 lbfSft).
9. Repeat this procedure by tightening four hex nuts, diametrically opposed and 90 degrees apart, to a torque of 27
N Sm (20 lbfSft).
10. Tighten the remaining hex nuts in a clockwise, criss‐cross pattern to 27 N Sm (20 lbfSft).
11. After the last hex nut is tightened to 27 N Sm (20 lbfSft), all of the hex nuts should be tightened again to 27 NSm
(20 lbf Sft) in a circular pattern around the bolt circle.
12. Once completed, no more tightening is recommended.
13. Mount the actuator on the valve by following the procedures in the Installation section.
Top‐Mounted Handwheel Assembly
A top‐mounted handwheel assembly (figures 9 and 10) is usually used as an adjustable casing‐mounted up travel stop
to limit full retraction of the actuator stem. Turning the handwheel clockwise moves the the handwheel stem (key
133, figures 9 and 10) down, compressing the spring.
Instructions are given below for complete disassembly and assembly of the top‐mounted handwheel assembly.
Perform the disassembly only as far as necessary to accomplish the required maintenance; then, begin the assembly at
the appropriate step.
Key numbers refer to figure 9 (sizes 30 through 60) and figure 10 (sizes 70 and 87), unless otherwise indicated.
Disassembly for Top‐Mounted Handwheel
1. Turn the handwheel (key 51) counter‐clockwise so that the handwheel assembly is not causing any spring
compression.
2. Bypass the control valve, reduce loading pressure to atmospheric, and remove the tubing or piping from the upper
handjack body (key 142, figures 9 or 10).