SAMSON 3271, 3277 technology data
Pneumatic Actuators up to 700 cm²
Type 3271 and
Type 3277 for integral positioner attachment
Application
Linear actuators in particular for attachment to Series 240, 250,
280 Control Valves and Type 3510 Micro-flow Valves
Diaphragm area 60 to 700 cm²
Rated travel 7.5 to 30 mm
The Types 3271 and 3277 Pneumatic Actuators contain a roll
ing diaphragm and internal springs.
Special features
Low overall height
•
Powerful thrust at high response speed
•
Low friction
•
Various bench ranges by varying the number of springs or
•
their compression
No special tools required to change the bench range and to
•
reverse the actuator action (also version with handwheel)
• Permissible operating temperatures from –50 to +120 °C
• Direct attachment of accessories on additional yoke for
Type 3277 with concealed travel pick-off (Figs. 2, 3 and 6)
Pneumatic actuator versions
– Type 3271 · Diaphragm areas 80, 240, 350, 700 cm²
(Fig. 1), optional stainless steel version (made of 1.4301 for
240, 350 and 700 cm²)
– Type 3277 · Diaphragm areas 240, 350, 355, 700 cm² for
direct attachment of accessories (Figs. 2, 3), optional stainless steel version (made of 1.4301 for 240, 350, 700 cm²)
–
Type 3271-52 · Diaphragm area 60 cm², aluminum hous
ing, especially for Type 3510 Micro-flow Valve (Fig. 4 and
Data Sheet T 8091 EN)
–
Type 3271-5 · Diaphragm area 120 cm², die-cast alumi
num housing (Fig. 5), optionally with additional handwheel
(Fig. 13a)
–
Type 3277-5 · Diaphragm area 120 cm², die-cast alumi
num housing for direct attachment of accessories (Fig. 10),
optionally with additional handwheel (Figs. 6 and 13b)
–
Types 3271 or 3277 · Additional handwheel with dia
phragm areas of 240, 350 or 700 cm² (Fig. 7, 12 and Data
Sheet T 8312 EN)
–
Type 3271 · Mechanical travel stop(Fig. 14), min. or max.
travel mechanically adjustable in versions with 120, 240,
350 or 700 cm²
–
Type 3271/7 · Fire-Lock version (Fig. 15) fail-safe action
in case of fire, in versions with 240, 350, 700 cm²
Further versions
–
Versions for other control media(e.g. water) · Details avail
able on request
-
Fig. 1 · Type 3271
Fig. 2 · Type 3277
Fig. 3 · Type 3277, 355 cm²
-
Fig. 4 · Type 3271-52
-
Fig. 5 · Type 3271-5
-
-
Fig. 6 · Type 3277-5
-
with additional handwheel
Fig. 7 · Type 3271 with
additional handwheel
Associated Mounting and Operating Instructions
Type 3271 Pneumatic Actuator EB 8310 EN
Type 3277 Pneumatic Actuator EB 8311 EN
Edition March 2010
Data Sheet T 8310-1 EN
Principle of operation
The signal pressure p
generates a forceF=pstx A on the dia
st
phragm area A (2). This force is balanced by the actuator
springs (4). Taking into account the rated travel, the number of
springs and their compression determine the bench range. The
travel H is proportional to the signal pressure p
. The operating
st
direction of the actuator stem (7) depends on the arrangement
of the springs and the signal pressure connection (1).
The stem connector (8) connects the actuator stem (7) with the
plug stem of the valve.
The adjustable mechanical travel stop (Fig. 14) is suitable for
actuators made of sheet steel with effective diaphragm areas of
120, 240, 350 or 700 cm². Using the travel stop, the actuator
travel can be limited by up to 50 % in both directions (actuator
stem extends or retracts) and permanently adjusted.
Actuators are available with the following fail-safe actions:
“Actuator stem extends (FA)“
The springs cause the actuator stem to move to the lower end
position (sectional drawings, right) when the diaphragm is re
lieved of pressure or when the supply air fails.
“Actuator stem retracts (FE)“
The springs cause the actuator stem to retract (sectional draw
ings, left) when the diaphragm is relieved of pressure or when
the supply air fails.
-
5
1
Fig. 10 · Type 3277-5 for direct attachment of accessories
-
-
2
4
7
11
6
5
2
4
5
7
1
11
1
2
4
5
3
6
Fig. 8 · Type 3271 (right: with additional springs)
1
2
4
7
11
6
8
Fig. 9 · Type 3277 for direct attachment of accessories
6
3
5
Fig. 11 · Type 3277, version with 355 cm² actuator area
2
1
7
8
1
2
4
3
5
5
3
6
9
10
23
18
12
6
3
5
2
1
7
8
Fig. 12 · Type 3271 with additional handwheel
1
Legend (Figs. 8 to 15)
1 Signal pressureconnection
2 Diaphragm
3 Vent
4 Springs
5 Diaphragm cases
6 Annular nut
7 Actuator stem
8 Stem connector
11 Yoke
12 Actuator stem to
handwheel
14 Cap
15 Nut
16 Spindle
17 Plain bearing
18 Lock nut
23 Handwheel
2
T 8310-1 EN
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