Samson 3275A, Mounting And Operating Instructions, Page: 14 / 52

3-2 EB 8314-1 EN
Design and principle of operation
The actuator with 804 cm² area does need a
yoke (see Fig. 3-2). The valve accessories
are mounted over the NAMUR interface.
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.
3.1 Fail-safe action
The double-acting piston actuator has no
springs. A defined final position is not
reached when the signal pressure is reduced
or the air supply fails.
3.2 Versions
Type 3275A Pneumatic Piston Actuator with
314, 380, 490 or 804 cm² actuator area:
−
Standard version
Cover and base are coated with an alu-
minum alloy (3.3547, anodized).
− Version with side-mounted handwheel
The actuator can be combined with a
Type 3273 Side-mounted Handwheel
with max. 30 mm travel (
u
T 8312).
− Special version with auxiliary spring
The actuator can be fitted with an auxil-
iary spring to move the actuator to a de-
fined end position in the depressurized
state (e.g. upon supply air failure).
7
6
9
2
11
1
1 Cover
2 Base
6 Cylinder barrel
7 Piston stem
9 Piston
11 Linkage
Fig. 3-2: Type 3275A Actuator (804 cm²)