Samson 3277 - Type 3277; Direction of Action

3-2 EB 8310-6 EN
Design and principle of operation
Several springs may be tted into one
another.
The stem connector clamps (A26/27) con-
nect the actuator stem (A7) with the plug
stem of the globe valve.
3.2 Type3277
The principle of operation is the same as that
of the Type3271 Actuator. The Type3277
Actuator is tted with an additional yoke on
the bottom diaphragm case (A2) (see
Fig.3-2). The yoke allows the direct attach-
ment of a positioner and/or limit switch. The
benet of this design is that the travel pick-
off located inside the yoke is protected
against external inuences.
Refer to the mounting and operating instruc-
tions of the valve accessories to be mounted
for more details on their attachment and the
accessories required.
3.3 Direction of action
The direction of action is determined by how
the springs (A10) and diaphragm plate (A5)
are arranged in the actuator.
With direction of action "actuator stem ex-
tends", the compressed air is applied to the
signal pressure connection on the bottom di-
aphragm case.
With direction of action "actuator stem re-
tracts", the compressed air is applied to the
Fig.3-2: Type 3277 Pneumatic Actuator
A1 Top diaphragm case
A2 Bottom diaphragm
case
A4 Diaphragm
A5 Diaphragm plate
A7 Actuator stem
A8 Ring nut
A10 Spring
A16 Vent plug
A26/27 Stem connector clamp
S Signal pressure
connection
Version with direction of action
"actuator stem retracts"
Version with direction of action
"actuator stem extends"
S
A1
S
A4
A10
A7
A8
A26/27
A16
A2
A5