Emerson Process Management FISHER 657 - Manual (Page 5)

Instruction Manual
D100306X012
657 Actuator (30-70 and 87)
December 2010
5
Figure 4. Bench Set Adjustment
SPRING ADJUSTER
LOWER BENCH SET
LOADING PRESSURE
UPPER BENCH SET
PRESSURE MARK
VALVE
STEM
RATED VALVE
TRAVEL MEASURE
MARK
VALVE
STEM HERE
UPPER BENCH SET
LOADING PRESSURE
ACTUATOR STEM
NOTES:
THE LOWER PSIG LOADING PRESSURE (MARKED ON NAMEPLATE) WHERE THE
FIRST MOVEMENT OF ACTUATOR STEM IS DETECTED.
THE UPPER PSIG LOADING PRESSURE EXTENDS ACTUATOR STEM.
MARK THIS POINT WITH TAPE OR A MARKER.
MEASURE DISTANCE OF TRAVEL. IT SHOULD EQUAL THE TRAVEL SPAN SHOWN
ON THE TRAVEL INDICATOR SCALE.
2
3
1
3 4
40A8715-B
B2426
1
2
3
4
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 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 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 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.