Emerson Fisher Design GX, Instruction Manual

Page: 13 / 60

GX Valve and Actuator
Instruction Manual
Form 5770
June 2006
13
halves in the proper orientation so that when looking
at the inside of the stem connector halves, the flats
are down and the beveled surfaces are up.
24. Align the pointer of the travel indicator (key 26)
with the appropriate mark on the travel scale.
25. Tighten the stem connector cap screws (key 25)
to 24 N
•
m (18 lbf
•
ft).
26. For air-to-open , release the actuator pressure.
27. For air-to-open , ensure the vent (key 21) is
installed into the upper diaphragm casing
(see figure 15 or 16).
For air-to-close , ensure the vent (key 21) is
installed into the actuator yoke air supply connection
(see figure 17 or 18).
Valve Trim Maintenance
Key numbers in this section refer to figures 15, 16,
17, 18, 19, and 20.
Valve Trim Disassembly
1. Remove the actuator and bonnet assembly as
described in the Replacing Packing section (steps 1
through 10).
D
For standard bonnet constructions
(figures 15, 16, 17, and 18) , proceed to the Seat
Ring Removal section.
D
For extension bonnet constructions
(figure 19), proceed to step 3.
D
For bellows bonnet constructions
(figure 20), proceed to step 2.
2. For bellows bonnet constructions (figure 20),
use a bellows nut tool made according to the
dimensions in figure 21 and table 10 to remove the
bellows nut (key 51) as follows:
a. Insert the bellows nut tool into the extension
bonnet (key 39). Be certain the tool lugs are
engaged in the corresponding recesses in the
bellows nut.
b. Use a torque gun or driver having sufficient
torque capabilities according to table 9. Connect
the gun to a socket that snugly fits the hex head
on the bellows nut tool.
Table 7. Seat Ring Torque Requirements
VALVE SIZE TORQUE
DN Inch N
S
m lbf
S
ft
15, 20, 25 0.5, 0.75, 1 170 124
40 1.5 320 234
50 2 460 337
80 3 1020 747
100 4 1520 1113
150 6 3400 2500
Table 8. Stem Extension Torque Requirements
VALVE SIZE TORQUE
DN Inch N
•
m Lbf
•
ft
15, 20, 25, 40, 50 0.5, 0.75, 1, 1.5, 2 40 30
80, 100 3, 4 120 89
Table 9. Bellows Nut Torque Requirements
VALVE SIZE TORQUE
DN Inch N
•
m Lbf
•
ft
15, 20, 25, 40, 50 0.5, 0.75, 1, 1.5, 2 350 260
80, 100 3, 4 650 480
c. Insert the socket onto the hex head of the
bellows nut tool.
WARNING
Be careful to hold the torque gun,
attached socket, and tool at right
angles to the bellows nut when
applying torque. Tilting the gun and
socket while applying torque may
cause the lugs on the bellows nut tool
to suddenly disengage from the lugs
on the bellows nut thus causing
possible damage to the bellows nut
and possible personal injury.
d. Remove the bellows nut (key 51).
3. For both extension and bellows bonnet
constructions: Body nuts (key 7) attach the
extension bonnet (key 39) to the valve body (key 1).
Loosen these nuts approximately 3mm (1/8 inch).
Then loosen the extension bonnet-to-body gasketed
joint by either rocking the extension bonnet or prying
between the body and extension bonnet. Work the
prying tool around the extension bonnet until it
loosens.
4. Remove the body nuts (key 7) completely and
carefully lift the extension bonnet (key 39), and valve
plug/stem extension assembly (key 3, 40 and 48) or
plug/bellows/stem extension assembly (key 3, 49
and 48) from the top of the valve body.