T 8392 EN
Type 3710 Reversing Amplifier

Application
Reversing amplifier to operate a double-acting pneumatic actuator using a single-acting pneumatic orelectropneumatic positioner or limit switch

The reversing amplifier is used in conjunction with singleacting electropneumatic positioners (Type 3725, Series 3730
and 3731) and is also suitable for use with device versions
37xx-x..x.05 and higher of Types 3766, 3767, and 3780
Positioners as well as Type 3768 Limit Switch.
The positioner is mounted either• Without pressure gauge• With one pressure gauge (when used with Type 4708-54Supply Pressure Regulator)• With two pressure gauges
VersionsStandard version without pressure gauge, including threaded
connections for pressure gauges · Suitable for max. 6 bar
supply pressure at a permissible ambient temperature from–25 to +80 °C, degree of protection IP 65 with filter checkvalve made of polyamide–

Fig. 1: Type 3710 Reversing Amplifier without and with twopressure gauges

Type 3710 (Fig. 1) · Reversing amplifier with pressuregauge connections at the front and backFurther versions–Type 3710 Reversing Amplifier with two pressure gauges(accessories) for Y1 and Y2 (see Fig. 1)–

With one pressure gauge for Y2 when used withType 4708-54 Supply Pressure Regulator (see Fig. 2)–

Degree of protection IP 65 with filter check valve made ofstainless steel–

Low-temperature versions for ambient temperatures from–50 to +80 °C and –60 to +80 °C–

Stainless steel version
Fig. 2: Type 3710 Reversing Amplifier, Type 4708-54 Supply
Pressure Regulator with Type 3730 Positioner mounted ona rotary actuator

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

Edition May 2010

Principle of operation
The reversing amplifier allows double-acting pneumatic actuators to be operated using single-acting positioners or limit
switches.
The positioner or limit switch creates an output signal pressure
Y1, to which the air pressure Y2 is added. The reversing amplifier uses the supply pressure Z as auxiliary power.

Risk of reversing amplifier damage due to incorrect mounting.
Before attaching the pressure gauges, remove the corresponding hexagon socket screws from the reversing amplifier. Insert
the seals supplied with the reversing amplifier into these holes.
NoteFor older versions (device versions lower thanType 37xx-x..x.05) of Types 3766, 3767, and 3780 Positioner and Type 3768 Limit Switch, a special connecting plate
must be used for attachment (see accessories, Table 4).

The following rule applies:
Y1 + Y2 = Z
ExampleY1 of the positioner
Supply pressure Z
Resulting Y2! NOTICE

1 bar
6 bar
5 bar

Positioner

Reversing amplifier

Supply air (max. 6 bar)Z

Supply 9Z

Y1Y1Output 38

Chamber 1

Air chamber 1 opens thevalve when the pressure rises
Pneumatic rotary actuator(double-acting)Y2

Pressure is added to
Y1 to create 6 bar

Chamber 2

Air chamber 2 closes thevalve when the pressure rises

Vent plug (IP 65)
CY1
Y2

Supply air
Output signal pressure
Resulting (opposing) signal pressure

Fig. 3: Schematic diagram of Type 3710 Reversing Amplifier

Table 1: Technical data
Type 3710 Reversing Amplifier
Permissible supply pressure

6 bar

KV coefficient

0.11

to fill the actuator with air
to vent the actuator

LeakageConnections
Degree of protection

0.12Z to Y2≤20 l/h when Y2 = 0 bar and Z = 6 bar

Y2 to vent

≤40 l/h when Y1 = 0 bar and Y2 = 6 bar¼-18 NPT · ISO 228/1-G ¼
IP 65

Compliance
Permissible ambient temperature–25 to +80 °C (–13 to +176 °F)
Low-temperature versions:–50 to +80 °C (–58 to +176 °F)–60 to +80 °C (–76 to +176 °F)

Weight2

0.5 kg · 1.2 kg for stainless steel version

T 8392 EN

Table 2: Materials
Type 3710 Reversing Amplifier
Housing and cover

Aluminum, powder coated, special version stainless steel 1.4404

Diaphragm plate

Aluminum, yellow chromatedSeat and plug

Brass

Diaphragms

Silicone rubber FVMQ · PTFE for low-temperature version

Table 3: Pressure gauge (optional accessories)
Pressure gauge Ø 40 mm
Indicating range

0 to 6 bar · 0 to 90 psi

Connection

G 1/8

Materials
Housing
Measuring unit and connection

Stainless steel, device free of copper
Stainless steel, free of copper · Nickel-plated brass connection

Table 4: Accessories
Type 3710 Reversing Amplifier · Accessories

Ordering no.:Accessories for attachment to Type 3725 Positioner
Connecting plate (including two self-tapping screws M5 x 50)

1402-0512

Pressure gauge (order number applies to one piece)
Pressure gauge 0 to 6 bar/psi/kPa; completely made of stainless steel, including pressure compensation element1402-1337

Pressure gauge 0 to 6 bar/psi/kPa; stainless steel/nickel-plated brass connection, including pressure compensation
element

1402-1338

Seal with spacer 1)

1099-4305

Mounting kit for Type 4708-54 Supply Pressure Regulator with Type 3710 Reversing AmplifierBolts with special nuts

1400-7806

Filter check valves
IP 66, 1.4404

1790-7253

NEMA 4, polyamide

1790-9645

NEMA 4, 1.4404

1790-9646

IP 65, polyamide

1790-7408

Connecting plate for older models of Types 3766, 3767 and 3780 Positioner as well as Type 3768 Limit Switch (device index .05 or lower)
Connecting plate1)

1400-9621

Two pieces included in the delivered state

Table 5: Article code
Reversing amplifier

Type 3710-

1xx

1

0xx

0

Housing material
Aluminum0

Stainless steel

13

Connecting thread
ISO 228/1-G ¼

1¼-18 NPT

2

Ambient temperature range–25 to +80 °C0–50 to +80 °C

13–60 to +80 °C

2

3

Degree of protection
IP 65, filter check valve made of polyamide

2IP 65, filter check valve made of stainless steel 1.4305

3T 8392 EN3

Type 3710 Reversing Amplifier with pressure gauges, mounted on Type 3730 Positioner

Output Y1

Supply (9)

86

56

80

52

Output Y2

80

Output Y1

Output Y2

130

3086
Ø101

90

166

164

15164

Type 3710 Reversing Amplifier with pressure gauges, mounted on Type 3725 Positioner
22108

29.5

M 20x1.5

87

Fig. 4: Dimensions in mm

Ordering text
Type 3710 Reversing Amplifier with threaded connections for pressure gauges
Can be used for Types 3725, 3730-x, and 3731-x Electropneumatic Positioners
Type 3766 Pneumatic Positioner, Type 3767 Electropneumatic Positioner, Type 3780 Electropneumatic Positioner with HART®
communicationor
Type 3768 Limit Switch
All devices in version 37xx-x...x.05 or higher
orFor attachment to Type 4708-54 Supply Pressure Regulator

Specifications subject to change without notice

T 8392 EN

2020-03-10 · English

With two pressure gauges for Y1 and Y2
one pressure gauge for Y2