Operation; Reversing The Operating Direction (Fail-Safe Action) - Samson 3277 Mounting And Operating Instructions

Operation

2 Operation
Note!
It is important for a trouble-free operation of
the Type 3277 Actuator that the vent plug
(3) is not blocked.
Make sure in versions with a handwheel that
the plug stem can move freely when the
valve is being positioned by the pneumatic
actuator by moving the handwheel into a
neutral position.
2.1 Reversing the operating
direction (fail-safe action)
The operating direction, i.e. fail-safe action,
of pneumatic actuators can be changed.
Prior to proceeding, you must remove the
actuator from the valve.
The fail-safe action is represented by a sym-
bol on the nameplate.
"Actuator stem extends"
"Actuator stem retracts"
Caution!
To disassemble an actuator with pre-
loaded actuator springs (recogniza-
ble by the long bolts on the di-
aphragm chambers), always undo
the short bolts first and then unthre-
ad the long bolts slowly and evenly
until the actuator springs are fully
decompressed.
6
EB 8311 EN
2.1.1 Standard actuator
Reversing the fail-safe action "Actuator
stem extends" to "Actuator stem retracts"
Note!
Actuators with 700 cm² (travel = 30 mm)
that are mounted to valves with 15 mm
travel, are preloaded by approx. 75 % on
mounting them to the valve.
The signal pressure range is recorded on the
nameplate when the actuators have been
preloaded on mounting them to the valve.
1. Unthread nuts and remove the bolts (9)
from the diaphragm cases.
2. Lift off the top diaphragm case (5) and
remove the springs (6).
3. Pull the actuator stem (2) with dia-
phragm plate (7) and diaphragm (8) out
of the yoke (10).
4. Unscrew nut (1), while holding the nut
(1.1) stationary or clamping the actuator
stem with a suitable tool.
Caution! Proceed carefully to avoid
damaging the seals of the actuator stem.