Emerson Process Management 3024C - Manual (Page 7)

3024C Actuator
Instruction Manual
Form 5760
March 2007
7
g. Slowly decrease and then increase the
diaphragm pressure several times stroking the
valve from the lower end to the upper end of the
spring range.
h. Apply air pressure to the diaphragm until the
valve is in the closed position. Loosen the screws
of the travel scale (key 26) and align it with the
indicator on the stem connector.
i. Stroke the valve full travel to ensure that the
travel matches the valve travel on the travel
indicator plate.
j. If the valve travel is not correct, repeat the
stem connector procedure. Remove the air
pressure from the diaphragm, remove the stem
connector and repeat steps c to i.
For a Type 3024C Air-to-Open Actuator
with a Push-Down-to-Close Valve:
a. Apply approximately 0.5 bar pressure above
the upper setting of the spring pressure range to
the bottom of the diaphragm. This positions the
actuator stem (key 8) at the highest point. The
spring range is stated on the nameplate or in
table 3.
b. Carefully place the actuator on the valve so
that the yoke boss fits over the valve bonnet.
c. Screw the yoke lock nut onto the bonnet and
tighten.
d. Lift the valve plug off the seat by the correct
travel for the valve. The travel is stated on the
nameplate or in table 1.
e. Place the stem connector half (key 50)
approximately halfway between the actuator and
valve stems but observing the F dimension in
table 5 so that any positioner lever (if fitted) is
horizontal at mid-travel. Be sure that the actuator
and valve stem threads are engaging the threads
of the stem connector by at least the distance of
one diameter of the stem.
f. Install the other half of the stem connector and
insert the socket screws and nuts and tighten
them.
g. Screw the two stem locknuts (key 52) up the
valve stem to the stem connector and tighten. Do
not over tighten.
h. Slowly decrease and then increase the
diaphragm pressure several times stroking the
valve from the lower end to the upper end of the
spring range.
i. Remove all air pressure from the diaphragm so
that the valve is in its closed position. Loosen the
screws of the travel scale (key 26) and align it
with the indicator on the stem connector.
j. Stroke the valve full travel to ensure that the
valve travel matches the valve travel on the travel
indicator plate.
k. If the valve travel is not correct repeat the
stem connector procedure. Apply approximately
0.5 bar pressure above the upper setting of the
spring range to the bottom of the diaphragm,
remove the stem connector and then repeat
steps d to j.
Note
When disassembling the stem
connector on Air-to-Open
constructions it is essential to apply
enough air pressure to the underside
of the diaphragm to lift the valve plug
off its seat. This will ensure that all
residual spring compression in the
actuator is supported while the stem
connector is removed.
Actuator Maintenance
Actuator parts are subject to normal wear and must
be inspected and replaced as necessary. The
frequency of inspection and replacement depends
upon the severity of the service conditions.
This section describes how the actuator can be
completely disassembled and assembled. When
inspection or repairs are required, disassemble only
those parts necessary to accomplish the job; then
start to assemble at the appropriate step.
Key numbers refer to figures 8 and 9.