Fisher 657 - Manual (Page 3)

Instruction Manual
D100307X012
657 Size 80 and 100 Actuators
December 2010
3
handwheel may be used as an auxiliary manual actuator. A side‐mounted handwheel assembly is normally used as an
auxiliary manual actuator.
Specifications
Refer to table 1 for specifications of the 657 actuator. See the actuator nameplate for information about a specific
actuator.
Maximum Pressure Limitations
The casing and diaphragm of 657 actuators are pressure operated. The air pressure provides force to compress the
spring and stroke the actuator. The following explanations describe the maximum pressure limitation for 657
actuators. Refer to the nameplate, warning tag, and table 1 for maximum values.
D Maximum Casing Pressure for Actuator Sizing: This is defined as the maximum pressure that can be applied to
stroke the actuator, overcome unbalance forces, and provide seat load.
D Maximum Diaphragm Casing Pressure: If the maximum diaphragm casing pressure is exceeded, damage to the
diaphragm, casing, or actuator may result. This pressure is not to be used for normal operating pressure.
WARNING
To avoid personal injury or parts damage, do not exceed the Maximum Diaphragm Casing Pressure listed in table 1. The
Maximum Diaphragm Casing Pressure must not produce a force on the actuator stem greater than the maximum allowable
actuator output thrust or the maximum allowable stem load.
Installation
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.
When an actuator and valve body are shipped together, the actuator is normally mounted on the valve. Follow 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 Actuator Mounting procedures as described below.
For information on mounting valve positioners, refer to the appropriate valve positioner instruction manual.
Actuator Mounting
1. To permit adjustment of the actuator spring, the size 100 actuator must be installed in a vertical position above the
valve body. Mount the actuator on the valve bonnet. Insert the cap screws, and tighten the hex nuts, securing the
actuator to the bonnet.