Actuators

Pneumatic, electric and electrohydraulic actuators for control valves
and butterfly valves

Diaphragm actuators up to 2800 cm²
Electric actuators up to 12.5 kN
Electrohydraulic actuator up to 7.7 kN
Hand-operated actuator

Edition July 2014

Information Sheet

T 8300 EN

Selection and application

Instrumentation

Actuators convert the control signal supplied by automationequipment (controller, control station, process control system)
into a linear or rotary motion used to position the final control
element (e.g. valve plug) in direct proportion to the control
signal received. For control valves, this converted motion is alinear motion (upward or downward). For butterfly valves,ball valves and rotary plug valves, this is a rotary motion up
to 70° opening angle for throttling applications. For on/off
service, this is a rotary motion up to 90°. The actuator together with the valve constitute the entire control valve assembly,
commonly referred to as the control valve.

Pneumatic actuators are field-proven, require little maintenance, and are inexpensive.
Accessories, such as positioners and converters, also act as
servo-boosters because they convert the low-volume output
signal y (0.2 to 1 bar) received from a controller into a powerful signal pressure pst up to 6 bar (90 psi).
Electric and electrohydraulic actuators are primarily used inapplications where compressed air is not available. A seriesof modules can also be added to these actuators, permitting
them to be adapted to the specific control task.

To meet plant requirements, the actuators can be equippedwith a wide range of transfer elements, such as positioners,
converters, solenoid valves, position transmitters and limit
switches. For details on selecting the additional equipment, refer to Information Sheet u T 8350 EN.

A Pneumatic
instrumentation

B Electropneumatic C Electric
instrumentation
instrumentation

A1

B1

C1C3

Instrumentation without positioner
Signal pressure range 0.2 to
1 bar (3 to 15 psi)

Instrumentation withelectropneumatic positioner
Signal pressure pst ≤ 6 bar(90 psi)

Instrumentation with AC motor
230 V ACElectrohydraulic actuator withthree-step control

pst
1pst
20,2 ... 1 bar
3 ... 15 psi

4 ... 20 mA
y8A2

B2C2C4

Instrumentation with pneumaticpositioner
Signal pressure pst ≤ 6 bar(90 psi)

Instrumentation with electropneumatic positioner
Signal pressure pst ≤ 6 bar(90 psi)

Instrumentation with reversing
contactor and three-phase AC
motor 380 V AC

Electrohydraulic actuator with
continuous electric control signal

1

pst

0.2 ... 1 bar
3 ... 15 psi

274

4 ... 20 mAy(also possible withfieldbus control)

394)
5)

M

11yWS

380 V ~

54

Legend for A1 to C43)

6y4pst2)

35230 V ~

41)

M

3

Pneumatic controller
Electric controller or automation system with mA output
Electric controller or automation system with three-step output
Pneumatic control valve
Electric control valve

2		6)
7)
8)
9)
10)
11)

3

4 ... 20 mAy10

6

Electrohydraulic control valve
Pneumatic positioner
Electropneumatic converter
Electropneumatic positioner
Electric positioner
Reversing contactor

T 8300 EN

Pneumatic actuators
The pneumatic actuators are diaphragm actuators with rolling
diaphragm and internal compression springs.
Benefits of pneumatic actuators:•• Designed for signal pressures up to 6 bar (90 psi)•• Low overall height•• Powerful thrust and high response speed•• Minimum friction•• Various bench ranges•• No special tools required to change the bench range or toreverse the operating direction of the actuator
Fail-safe action
Depending on the version, the actuators have two different
fail-safe actions which become effective when the pressure isrelieved from the diaphragm or the air supply fails:

Fig. 1: Type 3271 Pneumatic Actuator with additional handwheel
and Type 3241 Valve

Actuator stem extends (FA):The spring force moves the actuator stem to the lower end position.
Actuator stem retracts (FE):The spring force causes the actuator stem to retract.
Type 3271 Pneumatic Actuator (Fig. 1 and Fig. 2)•• For rated travels of 7.5 to 160 mm and diaphragm areasof 120, 175, 240, 350, 355, 700, 750, 1000, 1400 and2800 cm²•• Tandem actuator with effective area of 2 x 2800 cm²•• Optional version fitted with handwheel on the diaphragmcase for actuators with 120 to 700 cm² diaphragm areas(Fig. 1)

Fig. 2: Type 3271 Pneumatic Actuator and Type 3241 Valve•• 1400 to 2800 cm² diaphragm areas with side-mountedhandwheel•• For more details, refer to Data Sheets u T 8310-1 EN,u T 8310-2 EN and u T 8310-3 EN
Type 3277 Pneumatic Actuator (Fig. 3)•• Suitable for integral positioner attachment•• Diaphragm areas of 120, 175, 240, 350, 355, 700 or
750 cm²•• Rated travels from 7.5 to 30 mm•• Optionally with handwheel•• Refer to Data Sheet u T 8310-1 EN
Type 3204-1 and Type 3204-7 Pneumatic Actuator with Rotary Lever (Fig. 4)•• Pneumatic diaphragm actuators for final control elementswith rotary closure members, particularly for butterflyvalves and louvers (shutters)

Fig. 3: Type 3277 Pneumatic Actuator and Type 3241 Valve•• 350 or 700 cm² diaphragm areas•• Optionally with manual override•• Type 3204-7 Actuator suitable for integral positioner attachment•• Refer to Data Sheet u T 8316 EN
Fig. 4: Type 3204-1 Pneumatic Actuator with Rotary Lever

T 8300 EN		3

Type 3278 Pneumatic Rotary Actuator (Fig. 5)•• Single-acting rotary actuator with spring-return mechanism used for butterfly valves and other final control elements with rotary closure members•• 70° or 90° nominal opening angle•• 160 or 320 cm² diaphragm areas•• Optionally with manual override•• Refer to Data Sheet u T 8321 ENPfeiffer Type 31a Pneumatic Rotary Actuator (Fig. 6)•• Single-acting or double-acting piston actuator for final
control elements with rotary closure members•• 90° opening angle•• Optionally with additional manual override•• Suitable for throttling or on/off service•• Refer to Data Sheet u T 9929 EN

Fig. 5: Type 3278 Rotary Actuator with Type 3331 Butterfly Valveand Type 3767 Positioner

Electric and electrohydraulic actuators
Type 3274-11 to -23 Electrohydraulic Actuator (Fig. 7)•• Thrust up to 7.7 kN and 15 or 30 mm rated travel•• Transit times of 60 s and higher for three-step control orwith positioners for input signals from 0/4 to 20 mA or0/2 to 10 V

Fig. 6: Pfeiffer Type 31a Rotary Actuator•• Optionally with electric or mechanical override•• Version with fail-safe action available•• Refer to Data Sheet u T 8340 EN
Type SAM Electric Actuator (Fig. 8)•• Linear actuator with reversible motor with thrusts of 2 to25 kN for rated travels from 15 to 120 mm•• Transit times of 30 s and higher for three-step control orwith positioners for input signals from 0/4 to 20 mA or0/2 to 10 V•• With mechanical override, two torque-dependent andthree travel-dependent limit contacts•• Refer to Data Sheet u T 8330 EN

Fig. 7: Type 3274-... Electrohydraulic Actuator with electricoverride

Fig. 8: Type 3241-2 Electric Control Valve with Type SAM
Actuator

4		T 8300 EN

Type 3374 Electric Actuator (Fig. 9)•• Electric actuator for plant engineering and HVAC•• Thrust up to 2.5 kN•• Version:–– With or without fail-safe action–– For three-step control–– With digital positioner•• Refer to Data Sheet u T 8331 EN
Type 3375 Electric Actuator (Fig. 10)•• Electric actuator for plant engineering and HVAC•• Thrust up to 12.5 kN•• Version:–– For three-step control–– With digital positioner–– Version with fail-safe action (in preparation)

Fig. 9: Type 3374 Electric Actuator•• Refer to Data Sheet u T 8332 EN

Hand-operated actuator
Type 3273 Hand-operated Actuator (Fig. 11)•• For attachment to valves used as hand-operated controlvalves•• Particularly suitable for attachment to Series 240, 250and 260 Valves•• 15 to 30 mm rated travel · Nominal thrusts up to 32 kN•• Refer to Data Sheet u T 8312 ENFig. 10: Type 3375 Electric Actuator

Fig. 11: Type 3273 Hand-operated Actuator mounted on
Type 3241 Valve

T 8300 EN		5

SAMSON AG · MESS- UND REGELTECHNIK
Weismüllerstraße 3 · 60314 Frankfurt am Main, Germany
Phone: +49 69 4009-0 · Fax: +49 69 4009-1507
samson@samson.de · www.samson.de

T 8300 EN

2014-10-31 · English

Specifications subject to change without notice