Emerson Process Management 667 - Manual (Page 13)

Instruction Manual
D100311X012
667 Size 80 and 100 Actuators
May 2011
13
D Do not remove the actuator from the valve while the valve is still pressurized.
D Always wear protective gloves, clothing, and eyewear when performing any maintenance operations to avoid personal
injury.
D Disconnect any operating lines providing air pressure, electric power, or a control signal to the actuator. Be sure the
actuator cannot suddenly open or close the valve.
D Use bypass valves or completely shut off the process to isolate the valve from process pressure. Relieve process pressure
from both sides of the valve. Drain the process media from both sides of the valve.
D Vent the power actuator loading pressure and relieve any actuator spring precompression.
D Use lock‐out procedures to be sure that the above measures stay in effect while you work on the equipment.
D The valve packing box may contain process fluids that are pressurized, even when the valve has been removed from the
pipeline. Process fluids may spray out under pressure when removing the packing hardware or packing rings, or when
loosening the packing box pipe plug.
D Check with your process or safety engineer for any additional measures that must be taken to protect against process
media.
1. Isolate the control valve from the line pressure, release pressure from both sides of the valve, and drain the process
media from both sides of the valve. If using a power actuator, also shut off all pressure lines to the power actuator,
release all air pressure from the actuator. Use lock‐out procedures to be sure that the above measures stay in effect
while you work on the equipment.
2. Remove the shroud plate (key 65) by removing the cap head screws (key 66).
a. For small spring force, loosen the jam nut (key 26), and rotate the adjusting nut (key 25) until spring
compression is relieved.
b. For high spring force:
Note
To relieve spring compression when high spring forces exist, refer to the Spring section, and follow the instructions given for size
100 actuators with high spring force. These instructions outline the procedure required to decrease high spring compression.
Loosen the jam nut (key 26), and rotate the adjusting nut (key 25) until spring compression is relieved.
3. Remove the pressure tubing or piping from the top of the diaphragm casing.
4. For actuators with a top‐mounted handwheel (see figure 9), rotate the handwheel (key 58) clockwise as far as it will
go, unscrew the cap screws (key 54), and remove the gear case cover (key 53). Remove the travel stop cap screw, if
one is used, from the actuator stem extension (key 36), and unscrew the hex nuts (key 47). Unscrew the cap screws
that attach the gear case assembly (key 41) to the actuator, and remove the gear case assembly.
5. If necessary, remove the actuator from the valve by separating the stem connector (key 31) and removing the
actuator‐to‐bonnet bolting. Separate the stem connector by loosening the stem locknuts (key 69) and unscrewing
the four cap screws.
Note
If the actuator has been removed from the valve, ensure that it is in the vertical position. Then, block the actuator stem (key 144)
to support the weight of the actuator stem, spring seat and spring (keys 144, 19, and 18). This will facilitate removal of the nut
(key 24) or actuator stem connector (key 31, figure 8).