Emerson Fisher 656 Installation Instructions
Instruction Manual
D100304X012
Fisherr 656 Diaphragm Actuator
656 Actuator
August 2012
Contents
Introduction 1.................................
Scope of Manual 1.............................
Description 1.................................
Principle of Operation 2.........................
Specifications 2...............................
Maximum Pressure Limitations 3................
Installation 3..................................
Adjustment 3..................................
Maintenance 4.................................
Disassembly 4................................
Assembly 5...................................
Parts Ordering 7................................
Parts List 7....................................
Handwheel Assembly 7........................
Casing-Mounted Adjustable Down
Travel Stop 11..............................
Figure 1. Fisher 656 Actuator
W0454
Introduction
Scope of Manual
This instruction manual includes installation, maintenance, and parts information for Fisher 656 diaphragm actuators.
Refer to separate manuals for instructions covering the valve, positioner, and accessories.
Description
Fisher 656 actuators are long stroke, spring opposed, direct-acting diaphragm actuators. They operate Vee-Ballt
control valves, butterfly valves, built-in turbine valves, louvers, dampers and similar equipment. They are suitable for
either push-down-to-close (PDTC) or push-down-to-open (PDTO) applications and are available in sizes 30, 40 and 60
to provide 54 mm (2.125 inch), 64 mm (3.5 inch) and 105 mm (4.125 inch) travel, respectively.
Do not install, operate, or maintain a 656 actuator without being fully trained and qualified in valve, actuator, and
accessory installation, operation, and maintenance. To avoid personal injury or property damage, it is important to
carefully read, understand, and follow all the contents of this manual, including all safety cautions and warnings. If you
have any questions about these instructions, contact your Emerson Process Management sales office before
proceeding.
www.Fisher.com
656 Actuator
August 2012
Table 1. Specifications
Instruction Manual
D100304X012
Maximum Recommended Casing Operating
Pressure
(1)
Casing Pressure Connection
1/4 NPT internal
2.4 bar (35 psig)
Maximum Travel
(3)
(2)
Maximum
Diaphragm
(1)
,
Casing
Pressure
Bar (Psig)
(2,3)
,
Actuator Weight
Options
J Top-mounted handwheel/adjustable travel stop
J Casing-mounted adjustable down travel stop
Maximum Allowable Casing Pressure
Maximum
Actuator
Size
30 8.6 (125) 1.0 (15) 9.7 (140)
40 4.5 (65) 0.69 (10) 5.2 (75)
60 2.8 (40) 0.69 (10) 3.4 (50)
1. Additional pressure may be added when the actuator is at full travel. If the Maxi
mum Excess Diaphragm Pressure is exceeded, damage to the diaphragm or dia
phragm casing mightresult. See theMaximum Pressure Limitationsection.
2. Maximum diaphragm casing pressure must not be exceeded and mustnot produce
a force on the actuator stem greater than the max imum allowable actuator output
thrustorthemaximumallowablestemload.SeetheMaximumPressureLimitation
section.
3. This maximum casing pressure is not to be used for normal operating pressure. Its
purpose is to allow for typicalregulator supply settingsand/or relief valve tolerances.
Casing
Pressure for
Actuator
(2)
Sizing
Bar (Psig)
,
Maximum
Excess
Diaphragm
Pressure
Bar (Psig)
Operating Temperature Range
J -40 to 82C(-40to180F) with Nitrile Elastomer
J
-40 to 149C(-40to300F) with Silicone
Diaphragm
1. Control and stability may be impaired if thispressure is exceeded.
2. Exceeding this pressure can cause damage to the diaphragm, diaphragm casing,or other parts.
3. The temperaturelimits in thismanual and any applicablestandard or code limitation for valve should not be exceeded.
MAXIMUM RATED
STEM TRAVEL,
ACTUATOR SIZE
30 54 (2.125) Not available
40 89 (3.5) 76 (3)
60 105 (4.125) 97 (3.8125)
Actuator Size
30 23 (50)
40 32 (70)
60 73 (160)
mm (INCHES)
Standard
Travel
Stop
Approximate
Shipping Weight,
kg (Pounds)
Optional
Travel
Stop
Principle of Operation
In a direct acting diaphragm actuator, increasing loading pressure moves the actuator stem downward, compressing
the spring. When the diaphragm pressure is decreased, the spring moves the actuator stem upward. In the event of
failure of the loading pressure, the actuator stem moves to the extreme upward position.
Specifications
Refer to table 1 for Specifications of the 656 actuator. See the actuator nameplate for specific information for your
actuator.
WARNING
To avoid personal injury or damage to equipment that may result in the malfunction of the control valve or loss of control
of the process caused by excessive pressure, do not exceed the Maximum Pressures listed in table 1. Refer to the following
Maximum Pressure Limitations section.
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Instruction Manual
D100304X012
656 Actuator
August 2012
Maximum Pressure Limitations
The casing and diaphragm of 656 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 the nameplate or table 1 for maximum values for your actuator.
D Maximum Casing Pressure for Actuator Sizing: This is the maximum pressure that can be applied at less than full
travel of the actuator. If this stroking pressure is exceeded before the upper diaphragm plate contacts the travel
stop, damage to the stem or other parts might result.
D Maximum Excess Diaphragm Pressure: Additional pressure may be added when the actuator isatfulltravel.Ifthe
Maximum Excess Diaphragm Pressure is exceeded, damage to the diaphragm or diaphragm casing might result.
Because the actuator has traveled its specified travel, andthediaphragmheadisphysicallystoppedfrommovement,
the energy from any additional air pressure is transmitted to the diaphragm and diaphragm casings. 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. Exceeding this limiting factor could result in leakage or casing fatigue due to the deformation of the upper
diaphragm casing.
D Maximum Diaphragm Casing Pressure: If the Maximum Diaphragm Casing Pressure is exceeded, damage to the
diaphragm, diaphragm casing, or actuator might result.
Installation
When an actuator and valve are shipped together, the actuator is normally mounted on the valve. Follow the valve
instructions when installing the valve and actuator in a pipeline. If the actuator is shipped separately, or if it is
necessarytomounttheactuatoronthevalve,fourholeshavebeentappedintotheyokebosstoanchorittoa
mounting bracket.
WARNING
Always wear protective gloves, clothing, and eyewear when performing any maintenance operations to avoid personal
injury.
To avoid personal injury or property damage caused by bursting of pressure retaining parts, be certain the diaphragm
casing pressure does not exceed the limits listed in the Specifications table. Use pressure relieving or pressure limiting
devices to prevent the diaphragm casing pressure from exceeding these limits.
If installing into an existing application, also refer to the WARNING at the beginning of the Maintenance section in this
instruction manual.
To make the stem connection, follow the appropriate assembly step 10 in the Maintenance section. Standard actuator
sizes 30 and 40 have mounting holes tapped 3/8 inch UNC, and the size 60 mounting holes are tapped 1/2 inch UNC.
A 1/4 NPT loading pressure connection is located in the top of the upper diaphragm case. Using either pipe or tubing,
connect either the loading pressure connection or valve positioner input connection (if a valve positioner is furnished,
the loading pressure connection to the actuator will be made at the factory) to the output pressure connection on the
controller. Keep the length of the pipe or tubing as short as possible to avoid transmission lag in the control signal.
Adjustment
When the actuator is completely installed and connected to the controller, it should be checked for correct travel,
freedom from friction and correct PDTC or PDTO action.
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656 Actuator
August 2012
Instruction Manual
D100304X012
The actuator spring and diaphragm have been selected to meet the requirements of the application. It should be
noted that the actuator spring has a constant rate of compression and that adjustment of the spring compression
merely shifts the initial spring setpoint up or down to make the actuator travel within the initial spring setpoint and the
maximum diaphragm pressure indicated on the nameplate.
In some instances, however, such as high friction butterfly and ball valves, the actuator will fully stroke with less
diaphragm pressure than indicated on the nameplate. To increase the pressure required to initiate actuator stem
movement, turn the lower bearing seat (key 14) up toward the spring case. To decrease the pressure at which
movement begins, turn the lower bearing seat down, away from the spring case.
Maintenance
WARNING
Avoid personal injury or property damage from sudden release of process pressure or uncontrolled movement of parts.
Before performing any maintenance operations:
D Do not remove the actuator from the valve while the valve is still pressurized.
D Always wear protective gloves, clothing, and eyewear when performing any maintenance operations to avoid personal
injury.
D Disconnect any operating lines providingair 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 are working 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.
Disassembly
1. If the actuator is installed on a control valve, isolate or bypass the control valve.
2. Shut off the diaphragm loading pressure and remove the pipe or tubing from the loading pressure connection in
thetopofthediaphragmcase.
3. Turn the lower bearing seat (key 14) down, away from the spring case to relieve all spring compression.
4. If the entire actuator is to be removed from its mounting, disconnect the actuator stem (key 10) from the stem
connector, clevis, etc., and remove the jam nuts (key 23). Loosen the cap screws that hold the yoke (key 9) to its
mounting plate or bracket, and lift the entire actuator from its mounting.
5. Remove the diaphragm case cap screws and nuts (keys 19 and 20) and lift the upper diaphragm case (key 1 ) off t he
actuator. Remove the diaphragm (key 2).
6. Lift out the diaphragm plate (key 4) and stem (key 10). They may be separated by removing the cap screw (key 3).
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