Maximum Pressure Limitations; Installation; Actuator Mounting - Emerson Fisher Type 667 size 80 Instruction Manuals

WARNING
To avoid personal injury or parts dam-
age, do not exceed the Maximum Pres-
sures listed in table 1. Exceeding any of
the maximum pressures can result in
uncontrolled movement of parts, dam-
age to actuator parts and the control
valve, and loss of control of the pro-
cess. Use pressure-limiting or pressure-
relieving devices to prevent cylinder
pressure from exceeding these limits.

Maximum Pressure Limitations

The casing and diaphragm of Type 667 actuators are
pressure operated. This air pressure provides energy
to compress the spring, to stroke the actuator, and to
seat the valve. The following explanations describe the
maximum pressure limits for an actuator. Refer to
table 1 for maximum values.
Maximum Casing Pressure for Actuator
Sizing: This is the maximum pressure that can be ap-
plied at less than full travel of the actuator. If this
stroking pressure is exceeded before the upper dia-
phragm plate contacts the travel stop, damage to the
stem or other parts might result.
Maximum Excess Diaphragm Pressure: Addi-
tional pressure may be added when the actuator is at
full travel. If the Maximum Excess Diaphragm Pres-
sure is exceeded, damage to the diaphragm or dia-
phragm casing might result.
Because the actuator has traveled its specified travel,
and the diaphragm head is physically stopped from
movement, the energy from any additional air pressure
is transmitted to the diaphragm and diaphragm cas-
ings. The amount of air pressure that can be added
once the actuator has traveled to the stops is limited
by the resultant adverse effects that may occur. Ex-
ceeding this limiting factor could result in leakage or
casing fatigue due to the deformation of the upper dia-
phragm casing.
Maximum Diaphragm Casing Pressure: If the
Maximum Diaphragm Casing Pressure is exceeded,
damage to the diaphragm, diaphragm casing, or ac-
tuator might result. For some actuator sizes, the maxi-
mum casing pressure is the sum of the maximum
stroking pressure added to the maximum excess pres-
sure. For other actuator sizes, the value is lower than
the sum of the two pressures.
Type 667 Sizes 80 & 100
When an actuator and valve body are shipped togeth-
er, the actuator is normally mounted on the valve. Fol-
low the valve body instructions when installing the
control valve in the pipeline. If the actuator is shipped
separately or if it is necessary to mount the actuator
on the valve, perform the following Actuator Mounting
procedures.
For information on mounting valve positioners, refer to
the appropriate valve positioner instruction manual.

Actuator Mounting

1. Mount the actuator on the valve bonnet. Insert the
cap screws and tighten the hex nuts, securing the ac-
tuator to the bonnet.
2. Screw the valve stem jam nuts (key 69, figures 6
and 7) all the way onto the valve stem threads.
3. Connect an air supply to the lower diaphragm cas-
ing connection.
4. For push-down-to-close valves, be sure the valve
plug is on its seat. Reduce loading pressure to ensure
that the actuator stem is fully extended. Apply slight
loading pressure to retract the stem approximately
1/8-inch (3.2 mm).
5. For push-down-to-open valves, apply pressure to
ensure that the actuator stem is fully retracted. Be
sure the valve plug is on its seat. On large body sizes,
this may require the use of a pry bar inserted through
the body line opening. If the body is installed in a pipe-
line, the bottom flange (if one is used) can be removed
and the valve plug pushed to the seat from the bottom
opening. Reduce actuator loading pressure to extend
the stem approximately 1/8-inch (3.2 mm).
CAUTION
Incomplete engagement of either the
valve stem or actuator stem in the stem
connector can result in stripped threads
or improper operation. Be sure that the
length of each stem clamped in the stem
connector is equal to or greater than the
diameter of that stem.
6. Clamp the actuator and valve plug stems between
the two stem connector halves (key 31, figures 6 and
7). Insert and tighten the stem connector cap screws.
7. Thread the stem locknuts against the stem connec-
tor.
8. Align the travel indicator scale (key 32, figures 6
and 7) to show valve position.
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