CV500 Valve
Instruction Manual
Form 5302
July 2006
19
Adjusting Actuator Travel
Perform this procedure whenever the actuator is
removed or disconnected from the valve and
whenever the seat ring and retainer (keys 4 and 5)
are removed. Too little actuator travel will increase
shutoff leakage; too much travel will cause
excessive ball and seat ring torque and wear.
Any of the Fisher pneumatic, electric,
electrohydraulic, or manual actuators—or any other
actuator—must be adjusted for use with a Design
CV500 valve so that the ball is rotated to the fully
closed position. A gap of approximately 0.0254 mm
(0.001 inch) for temperatures to 260
_
C (500
_
F) or
0.1524 mm (0.006 inch) for higher temperatures
measured between the seat ring (key 5) and retainer
(key 4) indicates the fully closed position.
Note that this gap is also measured when
assembling the seat ring, retainer, and face seals to
ensure correct assembly. Measure the gap
according to this procedure to ensure proper
actuator adjustment. Merely completing the
assembly measurement is not sufficient.
Travel adjustments vary with the type of actuator
(some use turnbuckle assemblies; some use
externally adjusted travel stops; others use internal
limit switches). Refer to the actuator instruction
manual for adjustment instructions.
Note
When mounting the actuator, be sure
the ball (key 2) is closed. Do not use a
hammer or other tool to drive the
actuator lever onto the valve shaft.
Clean the valve shaft and actuator
lever splines to be sure the actuator
lever will slide on easily.
If the lever does not slide on easily,
carefully wedge the ball solidly against
the actuator-side thrust washer using
a screw driver or similar tool in the
same location as the pry bar in the
installation. Keep the wedge in place
while installing the lever, but again, do
not drive on the lever.
Remove the wedge after you have
clamped the actuator lever on the
valve shaft and connected the lever to
the actuator piston rod or diaphragm
rod.
1. Mount the actuator following the instructions in
the actuator instruction manual. Refer to figure 3 to
select actuator mounting style and position and to
orient the actuator lever with the valve drive shaft
(key 3).
2. For actuators with clamped levers, pull the drive
shaft (key 3) by hand toward the packing (key 13) so
that the ball (key 2) and thrust washer (key 12) are
tight against the bearing closest to the packing
(key 6 for 3- through 8-inch sizes and key 42 for 10-
and 12-inch sizes). Clamp the lever to the valve
drive shaft.
CAUTION
Do not apply full actuator signal
(pressure or power) to the actuator in
the next step. A full signal may wedge
the ball into the seat ring. Use a
regulated signal source and gradually
increase the signal to slowly stroke the
actuator.
3. Adjust the actuator travel and stroke the actuator
so that the ball is close to but not contacting the seat
ring at full actuator travel. If available on electric
actuators, use the manual handwheel to position the
plug.
4. Adjust the travel, using a full actuator signal, until
the ball contacts the seat ring around its full
circumference. This contact self-centers the seat
ring on the V-notch ball.
5. Continue to adjust the travel until a gap of
approximately 0.0254 mm (0.001 inch) exists
between the seat ring and retainer, as shown in
figure 12, at full actuator travel.
6. Refer to the actuator instruction manual to lock
the actuator travel adjustment.
Changing Valve Flow Direction
The Design CV500 valve may be installed in either
forward or reverse flow service. Standard flow
direction is forward flow enters the seat ring first,
then flows past the V-notch ball. If changing flow
direction is necessary, release all pressure from the
valve and actuator. Remove the control valve
assembly from the pipeline and rotate the assembly
about the valve drive shaft to put the retainer end of
the valve where the other end was. Refer to the
procedure for changing actuator mounting style if the
actuator must be repositioned, and refer to the
installation section to install the control valve
assembly. Be sure to reposition the flow direction
arrow on the valve.
