SAMSON TROVIS SAFE 3731-3 Explosion-Proof HART Digital Valve Positioner for Safety Instrumented Systems

Product description

The SAMSON TROVIS SAFE 3731-3 Explosion-Proof Valve Positioner is a specialized electropneumatic device for controlling pneumatic on/off valves in safety-instrumented applications. Designed with an Ex d flameproof enclosure, it is suitable for installation in appropriately certified hazardous areas.

The positioner operates using a 4–20mA input signal and HART communication. Its automatic initialization function adapts the positioner to the connected valve and actuator. The device evaluates the setpoint according to configured limits and moves the valve to the operating point or fail-safe position.

One of its key capabilities is integrated EXPERTplus diagnostics for safety-related on/off valves, including Partial Stroke Testing (PST). This allows valve movement to be tested without requiring a complete shutdown stroke, subject to the configured test procedure and plant safety requirements.

The TROVIS SAFE 3731-3 supports single-acting and double-acting pneumatic actuators and can be mounted on suitable linear and rotary valves. It is suitable for safety-related valve applications in oil and gas, petrochemical, chemical processing, power generation and other hazardous industrial facilities.

4. Technical specifications

5. Explosion protection certifications

Depending on the selected ordering code and certificate, available explosion-protection options include:

• ATEX: Ex db IIC T6 Gb and other specified protection configurations.

• IECEx: Ex d IIC T6/T5/T4 Gb; Ex db eb variants and dust protection configurations.

• FM and CSA: Approved hazardous-area configurations.

• JIS: Ex d IIC T6.

Important: Not every certificate is available on every configuration. Confirm the actual certificate and temperature class from the product nameplate and ordering code.

6. Key features and benefits

• Ex d explosion-proof enclosure for certified hazardous areas.

• SIL-certified design for safety-instrumented valve applications.

• HART communication for configuration and diagnostics.

• 4–20mA two-wire input signal.

• Integrated EXPERTplus safety-valve diagnostics.

• Partial Stroke Test (PST) functionality.

• Automatic initialization and calibration.

• Fail-safe valve positioning according to configured shutdown limits.

• Supports single-acting and double-acting actuators.

• Linear and rotary actuator mounting options.

• Local LCD display and menu-driven operation.

• Configurable emergency shutdown threshold.

7. Industrial applications in Bangladesh

• Oil and gas processing facilities

• LPG and LNG installations

• Petroleum refineries and storage terminals

• Chemical and petrochemical plants

• Power generation facilities

• Boiler and steam safety systems

• Pharmaceutical manufacturing plants

• Fertilizer and process industries

• Hazardous-area ETP and industrial process facilities

8. Compatibility and mounting

The SAMSON TROVIS SAFE 3731-3 supports installation on compatible pneumatic actuators using:

• SAMSON direct mounting

• NAMUR mounting according to IEC 60534-6-1

• Rotary actuator mounting according to VDI/VDE 3845

• Suitable linear and rotary pneumatic on/off valve assemblies

The correct mounting kit, actuator configuration, supply pressure and emergency shutdown version must be selected for the actual valve assembly.

9. Safety and purchasing notes

• SIL 2 suitability applies to a single device (HFT=0); SIL 3 suitability requires a redundant configuration (HFT=1), subject to the applicable functional-safety requirements.

• The positioner's SIL certification does not automatically make the complete safety instrumented function SIL compliant. The complete safety loop requires assessment and validation.

• Select the 0mA or 3.85mA emergency shutdown version according to the required safety logic.

• Confirm the hazardous-area classification and ATEX/IECEx/FM/CSA certificate before ordering.