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667 Size 80 and 100 Actuators
Instruction Manual
Form 1432
December 2007
6
For high spring forces, it is necessary to use
spacers between the bottom of the yoke and the
spring seat to isolate spring force from the adjusting
nut.
WARNING
To avoid personal injury from the
compressed actuator spring snapping
back to its original length, make and
use the spacers by following the
instructions in the steps below.
1. It is recommended that three spacers be made of
three-inch schedule 80 pipe cut to the appropriate
length specified in step 2. If other than the
recommended material is to be used, be certain that
the spacers are capable of withstanding the spring
force involved. The spacers must also be of equal
length with ends cut squarely.
2. Measure dimension B as shown in figure 3. Cut
the length of the spacers as follows:
a. If it is desired to decrease spring compression,
make the spacers approximately 4.8 mm
(3/16-inch) longer than dimension B.
b. If it is desired to increase spring compression,
make the spacers approximately 4.8 mm
(3/16-inch) shorter than either dimension B plus
the amount of adjustment required or dimension
B plus valve travel, whichever is less.
3. Whenever the total amount of adjustment
required is greater than valve travel, the adjustment
must be made in two or more steps, and the amount
of adjustment taken in each step must be less than
valve travel.
4. Pressure the actuator to attain full travel.
Cautiously insert the spacers at equal intervals
around the spring seat (key 19, figure 7). Spacers
must be seated squarely, or they may slip out of
position. Keeping hands and tools away from the
spring and spring seat, slowly decrease loading
pressure until the spring force holds the spacers
firmly between the spring seat and the bottom of the
yoke.
5. Loosen the jam nut. The adjusting nut can now
be rotated counterclockwise (when viewed from the
diaphragm casings) to increase the loading pressure
required to start actuator stem travel or clockwise to
decrease the pressure required to start travel.
Figure 3. Dimension B for Spring Adjustment
50A2627-C
A1007-1 / IL
SPRING SEAT
ADJUSTING NUT
JAM NUT
B
6. Pressure the actuator to move the spring seat
away from the spacers, and carefully remove the
spacers.
7. Slowly reduce the air pressure to the actuator.
Make sure that the thrust bearing (key 86) is
correctly seated in the spring seat before contact
with the adjustment nut (key 25) is made.
8. If the total adjustment required was greater than
valve travel, repeat the procedure. It will be
necessary to make new spacers using the new
dimension B and the remaining adjustment required
or valve travel, whichever is less. Tighten the jam
nut when adjustment is complete.
Maintenance
WARNING
Avoid personal injury or property
damage from sudden release of
process pressure or bursting of parts.
Before performing any maintenance
operations:
D Always wear protective gloves,
clothing, and eyewear when
performing any maintenance
operations to avoid personal injury.