8
EB 8026 EN
Assembling valve and actuator
3
Assembling valve and actua
-
tor
The basic pneumatic actuator can be re-
placed by a pneumatic actuator with addi-
tional handwheel or by an electric actuator.
A pneumatic actuator (with or without hand-
wheel) can be replaced by another pneumat-
ic actuator in a different size.
If the travel range of the actuator is larger
than the travel range of the valve, the springs
in the actuator are preloaded by SAMSON
so that the travel ranges match.
3.1
Assembly and adjustment
Proceed as follows if the valve and actuator
have not been assembled by SAMSON or if
the actuator is to be replaced by an actuator
of another type or size:
1.
Loosen the lock nut (6.2) and stem con
-
nector nut (6.1) on the valve.
2. Press the plug together with the plug stem
firmly into the seat ring. Thread down the
lock nut and stem connector nut.
3. Remove the clamps of the stem connector
(7) and the ring nut (8.2) from the actua-
tor (8).
4. Slide the ring nut over the plug stem.
5. Place the actuator onto the valve bonnet
(5) and secure it with the ring nut (8.2).
6. Read the bench range (or bench range
with preloaded springs) and the actua-
tor's fail-safe action from the actuator's
nameplate (e.g. 0.2 to 1 bar and "actua
-
tor stem extends").
The lower value corresponds to the lower
bench range value (0.2 bar) to be adjusted,
whereas the upper value corresponds to the
upper bench range value (1 bar).
The fail-safe action "actuator stem extends"
or "actuator stem retracts" is marked by
FA
or
FE
on the Type 3271 Actuator, and by a
corresponding symbol on the nameplate of
the Type 3277 Actuator.
7. For actuators with
"actuator stem ex
-
tends"
fail-safe action, apply a signal
pressure that corresponds to the lower
bench range value (e.g. 0.2 bar) to the
connection on the bottom diaphragm
chamber.
For actuators with
"actuator stem re
-
tracts"
fail-safe action, apply a signal
pressure that corresponds to the upper
bench range value (e.g. 1 bar) to the top
diaphragm chamber connection.
8.
Screw on the stem connector nut (6.1) by
hand until it touches the actuator stem
(8.1). Then turn it a further ¼ turn and
secure this position with the lock
nut (6.2).
9. Position clamps of the stem connector (7)
and screw them tight.
10.
Align the travel indicator (5.3) with the
tip of the stem connector.