Data Sheet

GX Control Valve and Actuator
D103171X012
Product Bulletin
51.1:GX
March 2012
17
Figure 15. Fisher GX Bellows Bonnet and Selection Process
W8958-1
PACKING
FOLLOWER
BONNET
LIVE-LOADED
PTFE PACKING
BODY/BONNET
GASKET
PURGE /
MONITORING
CONNECTION
BELLOWS NUT
BELLOWS
GASKET
BELLOWS/STEM
ASSEMBLY
EXTENSION
BONNET
BUSHING
VALVE PLUG
Step 1
Size and select the GX control valve that is appropriate
for the application. This will identify the:
S Valve body size
S Actuator size
S Orifice size
STrim style (balanced or unbalanced)
S Valve body material
Step 4
Using bulletin 51.1:GX(S1), verify the application pressure
drop does not exceed the actuator capability.
Step 2
Confirm bellows availability from table 14.
Step 3
Using table 15, select the bellows material combination
that is appropriate for the application. Using the
temperature limits shown in table 7, confirm the
selected construction is appropriate for the application
temperatures.
Step 5
Using figure 16, check to ensure the maximum process
pressure and temperature do not exceed the pressure-
temperature rating of the selected bellows.
Bellows Selection Process
Follow this process to assist in selecting the
appropriate bellows for the application.