Emerson Process Management FISHER 657 User Manual
Instruction Manual
Form 1900
February 2007
657 Actuator (30-70 and 87)
Type 657 Diaphragm Actuator
Sizes 30-70 and 87
Contents
Introduction 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope of Manual 1. . . . . . . . . . . . . . . . . . . . . . . . .
Description 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications 2. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mounting the Actuator on the Valve 4. . . . . . . . .
Discussion of Bench Set 5. . . . . . . . . . . . . . . . . . .
Spring Verification 5. . . . . . . . . . . . . . . . . . . . . . . .
Installing the Stem Connector Assembly 6. . . . .
Deadband Measurement 6. . . . . . . . . . . . . . . . . .
Loading Connection 8. . . . . . . . . . . . . . . . . . . . . . .
Maintenance 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Actuator Maintenance 8. . . . . . . . . . . . . . . . . . . . .
Top-Mounted Handwheel Assembly 10. . . . . . . .
Side-Mounted Handwheel for Sizes 34
through 60 Actuators 11. . . . . . . . . . . . . . . . . .
Side-Mounted Handwheel for Sizes 70
and 87 Actuators 12. . . . . . . . . . . . . . . . . . . . . .
Casing-Mounted Adjustable Travel Stops 14. . .
Parts Ordering 15. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts Kits 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Kits for Side-Mounted Handwheels 17. . . . . . . . .
Kits for Top-Mounted Handwheels 17. . . . . . . . .
Parts List 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Actuator Assembly (figures 6, 7, or 8) 17. . . . . .
Top-Mounted Handwheel (figures 9 or 10) 18. .
Side-Mounted Handwheel (figure 11 or 13) 18. .
Casing-Mounted Adjustable Up Travel Stops
(figures 14 or 15) 22. . . . . . . . . . . . . . . . . . . . . .
Casing-Mounted Adjustable Down Travel Stops
(figure 16) 23. . . . . . . . . . . . . . . . . . . . . . . . . . . .
W2174-2/IL
Figure 1. Type 657 or 657-4 Actuator Mounted
through 70 and size 87. The Type 657-4 actuator in
sizes 70 and 87 is also covered. Refer to separate
instruction manuals for information about the valve
positioner and other accessories used with these
actuators.
on an easy-e
R
Valve
Introduction
Scope of Manual
This instruction manual provides information on
installation, adjustment, maintenance, and parts
ordering for the Type 657 actuator in sizes 30
www.Fisher.com
Do not install, operate, or maintain a Type 657
actuator without first D being fully trained and
qualified in valve, actuator, and accessory
installation, operation, and maintenance, and D
carefully reading and understanding the contents of
this manual. If you have any questions about these
instructions, contact your Emerson Process
Managementt sales office before proceeding.
D100306X012
Instruction Manual
(1)
Acceptable Valve
Maximum Allowable
(2)
Maximum Diaphragm
Material Temperature
Pressure Connections
Form 1900
657 Actuator (30-70 and 87)
Table 1. Specifications
SPECIFICATION
2
Nominal Effective Area
Yoke Boss Diameters
Acceptable Valve
Stem Diameters
Maximum Allowable
Output Thrust
Maximum Travel
Maximum Casing
Pressure for
Actuator Sizing
Maximum Diaphragm
Casing Pressure
Material Temperature
Capabilities
Pressure Connections
(female)
Approximate Weights
1. These values also apply to the Type 657-4 actuator construction.
2. Actuator travel may be less than the value listed after connecting the actuator to the valve.
3. Maximum travel for Type 657-4 is 102 mm (4 inches).
4. Normal operating diaphragm pressure must not exceed maximum diaphragm casing pressure and must not produce a force on the actuator stem greater than the maximum allowable
output thrust or the maximum allowable valve stem load. Contact your Emerson Process Management sales office with questions concerning maximum allowable valve stem load.
5. This maximum casing pressure is not to be used for normal operating pressure. Its purpose is to allow for typical regulator supply settings and/or relief valve tolerances.
(4)
(4)
(4)(5)
cm
2
Inch
mm 54 54 71 71 71 90 90 90 127
Inches 2-1/8 2-1/8 2-13/16 2-13/16 2-13/16 3-9/16 3-9/16 3-9/16 5
mm 9.5 9.5 12.7 12.7 12.7 19.1 19.1 19.1 25.4
Inches 3/8 3/8 1/2 1/2 1/2 3/4 3/4 3/4 1
N 10230 10230 12010 25131 33582 25131 30246 39142 39142
Lb 2300 2300 2700 5650 7550 5650 6800 8800 8800
mm 19 29 38 51 51 51 51 76
Inches 0.75 1.125 1.5 2 2 2 2 3
Bar 8.6 4.5 4.5 3.4 2.8 3.4 2.8 3.8 3.8
Psig 125 65 65 50 40 50 40 55 55
Bar 9.6 5.2 5.2 4.1 3.4 4.1 3.4 4.5 4.5
Psig 140 75 75 60 50 60 50 65 65
_C Nitrile Elastomers: –40 to 82_C, Silicone Elastomers: –54 to 149_C, Fluorocarbons: –18 to 149_C
_F Nitrile Elastomers: –40 to 180_F, Silicone Elastomers: –65 to 300_F, Fluorocarbons: 0 to 300_F
1/4 In. NPT X X X X X X X - - - - - -
1/2 In. NPT - - - - - - - - - - - - - - - - - - - - - X X
kg 16 22 23 37 49 42 53 107 116
Lb 36 48 51 82 107 92 116 235 255
30 34 40 45 46 50 60 70
297 445 445 677 1006 677 1006 1419 1419
46 69 69 105 156 105 156 220 220
ACTUATOR SIZE
February 2007
(1)
(3)
(3)
87
76
(1)
(3)
(3)
3
Note
Neither Emerson, Emerson Process
Management, nor any of their affiliated
entities assumes responsibility for the
selection, use and maintenance of any
product. Responsibility for the
selection, use, and maintenance of any
product remains with the purchaser
and end-user.
Description
The Type 657 actuator (figure 1) and the Type 657-4
actuator are direct-acting, spring-opposed
diaphragm actuators. They provide automatic
operation of control valve body assemblies. The
Type 657 actuator offers 76 mm (3 inches)
maximum actuator travel. The Type 657-4 actuator
provides 102 mm (4 inches) maximum actuator
travel. Both actuators position the valve plug in
response to varying pneumatic loading pressure on
the actuator diaphragm. Figure 2 shows the
operation of these actuators.
A Type 657 or 657-4 actuator can be equipped with
either a top-mounted or a side-mounted handwheel
assembly. A top-mounted handwheel assembly is
used as an adjustable up travel stop to limit actuator
travel in the up direction (see figure 2). A
side-mounted handwheel assembly is usually used
as an auxiliary manual actuator. Adjustable
casing-mounted up or down travel stops are also
available for this actuator.
Note
If repeated or daily manual operation is
expected, the actuator should be
equipped with a side-mounted
handwheel rather than a
casing-mounted travel stop or
top-mounted handwheel.
The side-mounted handwheel is
designed for more frequent use as a
manual operator.
Specifications
Refer to table 1 for Specifications of the Type 657
and 657-4 actuators. See the actuator nameplate for
specific information about your actuator.
2
Instruction Manual
Form 1900
February 2007
657 Actuator (30-70 and 87)
AIR PUSHES
STEM DOWN
SPRING LIFTS
STEM UP
STEM
AF3833-A
A0792-2/IL
Figure 2. Schematic of Type 657 and 657-4 Actuators
Installation
Key number locations are shown in figures 6, 7,
and 8, unless otherwise indicated. Also, refer to
figure 3 for location of parts.
WARNING
Always wear protective gloves,
clothing, and eyewear when
performing any installation operations
to avoid personal injury.
Check with your process or safety
engineer for any additional measures
that must be taken to protect against
process media.
If installing into an existing
application, also refer to the WARNING
at the beginning of the Maintenance
section in this instruction manual.
NPT FEMALE
CONNECTION
DIAPHRAGM CASING
DIAPHRAGM AND
STEM SHOWN IN
UP POSITION
DIAPHRAGM
PLATE
LOWER DIAPHRAGM CASING
ACTUATOR SPRING
ACTUATOR STEM
SPRING SEAT
SPRING ADJUSTOR
STEM CONNECTOR
YOKE
TRAVEL INDICATOR DISK
INDICATOR SCALE
W0363–1/IL
VALVE STEM
YOKE LOCK NUT
YOKE BOSS
DIAMETER
BONNET
TYPICAL VALVE
(REFER TO
VALVE MANUAL)
W6199–1/IL
Figure 3. Actuator Mounting Components for Size 30
through 70 Actuators
MATCH
LINE
FOR
ACTUATOR
CAUTION
To avoid parts damage, do not use an
operating pressure that exceeds the
Maximum Diaphragm Casing Pressure
(table 1) or produces a force on the
actuator stem greater than the
Maximum Allowable Output Thrust
(table 1) or the maximum allowable
valve stem load. (Contact your
Emerson Process Management sales
office with questions concerning
maximum allowable valve stem load.)
D Valve/Actuator Assembly: If the actuator and
valve are shipped together as a control valve
assembly, it has been adjusted at the factory, and
may be installed in the pipeline. After installing the
valve in the pipeline, refer to the Loading Connection
procedures.
D Actuator Mounting: If the actuator is shipped
separately or the actuator has been removed from
the valve, it is necessary to mount the actuator on
the valve before placing the valve in the pipeline.
Refer to the actuator mounting procedures before
placing the valve in service. You may perform the
Bench Set Spring Adjustment procedures in this
3
657 Actuator (30-70 and 87)
Instruction Manual
Form 1900
February 2007
SPRING ADJUSTER
LOWER BENCH SET
LOADING PRESSURE
UPPER BENCH SET
PRESSURE MARK
NOTES:
1
THE LOWER PSIG LOADING PRESSURE (MARKED ON NAMEPLATE)
WHERE THE FIRST MOVEMENT OF ACTUATOR STEM IS DETECTED.
2
THE UPPER PSIG LOADING PRESSURE EXTEND ACTUATOR STEM.
3
MARK THIS POINT WITH TAPE OR A MARKER.
MEASURE DISTANCE OF TRAVEL. IT SHOULD EQUAL THE TRAVEL SPAN
4
SHOWN ON THE TRAVEL INDICATOR SCALE.
40A8715–B
B2426 / IL
VALVE
STEM
1
3
RATED VALVE
TRAVEL MEASURE
4
MARK VALVE
STEM HERE
Figure 4. Bench Set Adjustment
section to confirm that the adjustment has not
changed since it was shipped from the factory.
D Positioner: If a positioner is installed, or is to
be installed on the actuator, refer to the positioner
instruction manual for installation. During the
adjustment procedures, it will be necessary to
provide a temporary loading pressure to the actuator
diaphragm.
Mounting the Actuator on the Valve
The Type 657 actuator spring loading pushes the
actuator stem up towards the actuator diaphragm
(see figure 2). This spring action moves the stem
away from the valve while installing the actuator.
CAUTION
If the valve stem is allowed to remain
in the up position (towards the
actuator) during mounting, it can
interfere with the actuator mounting,
possibly damage valve stem threads
or bend the valve stem. Be sure the
valve stem is pushed down (into the
ACTUATOR
STEM
UPPER BENCH SET
3
2
LOADING PRESSURE
valve body), away from the actuator
while mounting.
Provide a temporary method of applying diaphragm
loading pressure to the diaphragm to extend the
actuator stem during bench set spring adjustments.
1. Provide a vise or some other method of
supporting the valve and the weight of the actuator
during assembly. For direct or reverse acting valves,
push the valve stem down away from the actuator
while mounting the actuator.
2. Screw the stem locknuts all the way onto the
valve stem. With the concave side of the travel
indicator disk (key 14) facing the valve, install the
travel indicator disk on the valve stem. (Note: The
travel indicator disk is not used with size 87
actuators.)
3. Lift or hoist the actuator onto the valve bonnet:
a. For size 87 actuators, insert the cap screws
and tighten the hex nuts, securing the actuator to
the bonnet.
b. For all other size actuators, screw the yoke
locknut onto the valve bonnet and tighten the
locknut. (Note: On small size actuators, it may be
necessary to remove the indicator disk and
re-install it while lowering the actuator on to the
4
Instruction Manual
Form 1900
February 2007
657 Actuator (30-70 and 87)
valve because the disk will not go through the
actuator yoke opening).
4. Do not connect the actuator stem to the valve
stem at this time. Whenever the actuator is installed
on the valve, it is recommended to perform the
Bench Set Spring Adjustment procedure to verify
that the actuator is still adjusted correctly.
Discussion of Bench Set
The bench set pressure range is used to adjust the
initial compression of the actuator spring with the
valve-actuator assembly “on the bench.” The correct
initial compression is important for the proper
functioning of the valve-actuator assembly when it is
put into service and the proper actuator diaphragm
operating pressure is applied.
The bench set range is established with the
assumption that there is no packing friction. When
attempting to adjust the spring in the field, it is very
difficult to ensure that there is no friction being
applied by “loose” packing.
Accurate adjustment to the bench set range can be
made during the actuator mounting process by
making the adjustment before the actuator is
connected to the valve (see the Spring Verification
Procedure).
If you are attempting to adjust the bench set range
after the actuator is connected to the valve and the
packing tightened, you must take friction into
account. Make the spring adjustment such that full
actuator travel occurs at the bench set range (a) plus
the friction force divided by the effective diaphragm
area with increasing diaphragm pressure or (b)
minus the friction force divided by the effective
diaphragm area with decreasing diaphragm
pressure.
For an assembled valve-actuator assembly, the
valve friction may be determined by following the
procedure described below:
1. Install a pressure gauge in the actuator loading
pressure line that connects to the actuator
diaphragm casing.
Note
Steps 2 and 4 require that you read
and record the pressure shown on the
pressure gauge.
2. Increase the actuator diaphragm pressure and
read the diaphragm pressure as the actuator
reaches its mid-travel position.
3. Increase the actuator diaphragm pressure until
the actuator is at a travel position greater than its
mid-travel position.
4. Decrease the actuator diaphragm pressure and
read the diaphragm pressure as the actuator
reaches its mid-travel position.
The difference between the two diaphragm pressure
readings is the change in the diaphragm pressure
required to overcome the friction forces in the two
directions of travel.
5. Calculate the actual friction force:
Friction
Force, = 0.5
pounds
Difference
in pressure
readings, psig
Effective
diaphragm area,
inches
2
Refer to table 1 for the effective diaphragm area.
When determining valve friction, you can make
diaphragm pressure readings at a travel position
other than mid-travel if you desire. If you take
readings at zero or at the full travel position, take
extra care to ensure that the readings are taken
when the travel just begins or just stops at the
position selected.
It is difficult to rotate the spring adjustor (key 12,
figure 6, 7, and 8) when the full actuator loading
pressure is applied to the actuator. Release the
actuator loading pressure before adjusting. Then
re-apply loading pressure to check the adjustment.
Spring Verification
Ensure that the actuator stem is at the top of its
travel as shown in figure 4 and not connected to the
valve. (Note: Some spring compression is required
to move the diaphragm to the top of its travel.) The
bench set steps provided are the same for direct or
reverse acting valves.
WARNING
When moving the actuator stem with
diaphragm loading pressure, use
caution to keep hands and tools out of
the actuator stem travel path. Personal
injury and/or property damage is
possible if something is caught
between the actuator stem and other
control valve assembly parts.
Also, provide a certified pressure gauge suitable to
accurately read the diaphragm pressure from 0
through the upper bench set pressure marked on the
5
657 Actuator (30-70 and 87)
Instruction Manual
Form 1900
February 2007
nameplate. Apply loading pressure to the
diaphragm.
CAUTION
Stroke the actuator a few times to
ensure that the pressure gauge is
working correctly, and that the
actuator is functioning properly. To
prevent product damage, it is
important to be sure that the actuator
assembly is not
any loading friction on the actuator
stem movement.
1. If not already accomplished, provide a temporary
means of applying an adjustable loading pressure to
the actuator during bench set adjustments.
2. Set the diaphragm loading pressure at 0 psig.
Then, slowly raise the pressure from 0 psig towards
the lower bench set pressure while checking for the
first movement of the actuator stem. The actuator
stem should show movement at the lower bench set
pressure. If movement occurs before or after the
lower pressure is reached, adjust the spring adjuster
(see figure 4) into or out of the yoke until the
actuator stem’s movement is first detected at the
lower bench set pressure.
3. Be sure the spring adjuster is adjusted to meet
the requirements of step 2 above.
4. Apply the upper bench set loading pressure to
the diaphragm. This pressure extends the actuator
stem down towards the valve. (Note: the actuator
stem may slide over the valve stem as shown in
figure 4.) At the end of the actuator stem, use a
marker or a piece of tape to mark the valve stem
(see figure 4). (Note: If the actuator stem does not
pass over the valve stem, provide a method to mark
this point of stem travel.).
5. Slowly decrease the diaphragm loading pressure
until the lower bench set pressure is applied.
Measure the distance between the marker or tape
on the valve stem to the end of the actuator stem.
The distance should match the travel span shown on
the travel indicator scale (key 18). If the span of
travel is correct, bench set is complete. Proceed to
the Installing the Stem Connector Assembly
subsection.
6. If the travel span is not correct, a wrong or
damaged spring has been installed in the actuator.
To obtain the correct spring sizing information, refer
to Catalog 14, Actuator Sizing and Sample
Calculation sections to determine the correct spring
binding or producing
selection for your application. Or, contact your
Emerson Process Management sales office for
assistance. After replacing the spring, repeat the
steps above.
Installing the Stem Connector
Assembly
When installing the stem connector assembly
(key 26), the actuator and valve stem threads should
engage the threads of the stem connector by the
distance of the diameter of the stem.
Note
Replacement stem connectors are an
assembly of two stem connector
halves, cap screws, and a spacer
between the connector halves.
Remove the spacer and discard, if
present, before clamping the actuator
and valve stems together.
1. If necessary, push the valve stem down so that it
is touching the seat ring on direct acting valves. For
reverse acting valves, push the stem down to the
open position.
If necessary, screw the valve stem locknuts down,
away from the connector location. For all actuators
except size 87, ensure that the travel indicator disk
(key 14) is located on top of the locknuts.
2. Slowly increase the diaphragm pressure to the
upper bench set pressure. This should be the same
pressure used in the bench set steps, and it is
marked on the nameplate.
3. Place the stem connector half with the threaded
holes, approximately half way between the actuator
and valve stems. Refer to figures 6, 7, and 8 to help
locate the connector position.
Be sure that the actuator and valve stem threads are
engaging the threads of the stem connector by the
distance of one diameter of the stem.
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 one diameter of that stem.
Damage to threads on either stem or in
the stem connector can cause the
parts to be replaced prematurely.
6
Instruction Manual
Form 1900
February 2007
657 Actuator (30-70 and 87)
CLOSING
UPPER
BENCH SET
PRESSURE
LOWER
DIAPHRAGM PRESSURE, PSIG
BENCH SET
PRESSURE
NOTE:
1
DEADBAND IS CAUSED BY FRICTION.
A6763-2 / IL
15
9
3
0
OPEN
DIRECT ACTING VALVE REVERSE ACTING VALVE
VALVE
OPENING
VALVE
MID RANGE
VALVE TRAVEL
Figure 5. Typical Valve Response to Deadband
RANGE OF
DEADBAND
CLOSED
1.0
0.6
1
0.2
4. Install the other half of the stem connector and
insert the cap screws and tighten them. If installing a
positioner, also attach the feedback bracket at the
same time.
5. Screw the valve stem locknuts up until the
indicator disk contacts the bottom of the stem
connector, or for size 87 actuators, the stem
connector. Do not overtighten the locknuts.
6. Slowly decrease and then increase pressure
several times stroking the valve from the lower
bench set pressure to the upper pressure.
Be sure that the valve is in closed position (up or
down, depending on valve action). Loosen the
screws on the travel scale, and align it with the travel
indicator disk or stem connector. Stroke the valve full
travel to ensure that the travel matches the valve
travel on the travel indicator plate. If valve travel is
not correct, repeat the stem connector procedure.
Note
OPENING
UPPER
BENCH SET
PRESSURE
DIAPHRAGM PRESSURE, BAR
LOWER
DIAPHRAGM PRESSURE, PSIG
BENCH SET
PRESSURE
15
9
3
0
CLOSED
VALVE
CLOSING
VALVE
MID RANGE
VALVE TRAVEL
RANGE OF
DEADBAND
OPEN
Deadband Measurement
Deadband is caused by packing friction, unbalanced
forces, and other factors in the control valve
assembly. Deadband is the range a measured signal
can vary without initiating a response from the
actuator (see figure 5). Each actuator spring has a
fixed spring rate (force). You have verified that the
right spring was installed in the actuator by
completing the Bench Set Spring Adjustment steps.
Deadband is one factor that affects the control valve
assembly operation during automatic loop control.
The control loop tolerance for deadband varies
widely depending on the loop response. Some
common symptoms of the deadband being too wide
are no movement, a “jump” movement, or oscillating
movements of the actuator during automatic loop
control. The following steps are provided to
determine the span of deadband. The percent of
deadband is helpful in troubleshooting problems with
the process control loop.
1.0
0.6
1
DIAPHRAGM PRESSURE, BAR
0.2
For push-down-to-close valves, the
valve plug seat is the limit for
downward travel and the actuator
up-stop is the limit for upward (away
from the valve) movement. For
push-down-to-open valves, the
actuator down stop is the limit for
downward movement, and the valve
seat is the limit for upward (away from
the valve) movement.
1. Start at a pressure near the lower bench set
pressure, slowly increase pressure until the valve is
approximately at mid-travel. Note this pressure
reading.
2. Slowly decrease pressure until movement of the
valve stem is detected, and note this pressure.
3. The difference between these two pressures is
deadband, in psi.
7
657 Actuator (30-70 and 87)
Instruction Manual
Form 1900
February 2007
4. Calculate the percent of deadband by:
Deadband, psi
Deadband = —————————————— = nn%
Bench Set Span, psi
Loading Connection
The loading pressure connections are made at the
factory if the valve, actuator, and positioner come as
a unit. Keep the length of tubing or piping as short as
possible to avoid transmission lag in the control
signal. If a volume booster, valve positioner or other
accessory is used, be sure that it is properly
connected to the actuator. Refer to the positioner
instruction manual or other manuals as necessary.
For actuators shipped separately or whenever the
actuator pressure connections are installed, use the
following steps:
1. Connect the loading pressure piping to the NPT
female connection in the top of the diaphragm
casing.
2. For sizes 70 and 87 actuators, if necessary,
remove the 1/4 inch NPT bushing if a 1/2 inch NPT
female connection is needed to increase connection
size. The connection can be made with either piping
or tubing.
3. Cycle the actuator several times to be sure that
the valve stem travel is correct when the correct
pressure ranges are applied to the diaphragm.
WARNING
If valve stem travel appears to be
incorrect, refer to the Bench Set
Spring Adjustment procedures at the
beginning of this section. To avoid
personal injury or product damage, do
not place the valve into service if it is
not reacting correctly to diaphragm
loading pressure changes.
Maintenance
Actuator parts are subject to normal wear and must
be inspected and replaced when necessary. The
frequency of inspection and replacement depends
on the severity of service conditions.
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.
D Disconnect any operating lines
providing air pressure, electric power,
or a control signal to the actuator. Be
sure the actuator cannot suddenly
open or close the valve.
D Use bypass valves or completely
shut off the process to isolate the
valve from process pressure. Relieve
process pressure from both sides of
the valve. Drain the process media
from both sides of the valve.
D Vent the power actuator loading
pressure and relieve any actuator
spring precompression.
D Use lock-out procedures to be
sure that the above measures stay in
effect while you work on the
equipment.
D The valve packing box may
contain process fluids that are
pressurized, even when the valve has
been removed from the pipeline.
Process fluids may spray out under
pressure when removing the packing
hardware or packing rings, or when
loosening the packing box pipe plug.
D Check with your process or safety
engineer for any additional measures
that must be taken to protect against
process media.
Actuator Maintenance
This procedure 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 the assembly at the appropriate step.
Key numbers refer to figures 6, 7, or 8 unless
otherwise indicated. Figure 6 shows the sizes 30
through 60 actuators, figure 7 illustrates the sizes 70
actuator, and figure 8 shows the size 87 actuator.
8
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