Valves with NAMUR-Interface - Pneumatically actuated valves | Hafner

Pneumatically Actuated Hafner NAMUR Valves

Hafner PN series are pneumatically actuated valves with NAMUR interface, designed for direct mounting on rotary actuators in process valve automation. Actuation is achieved via pilot air, eliminating the need for an electrical coil on the valve. The NAMUR interface complies with VDI/VDE 3845 standards for actuator port configuration.

Available Functions

• PN 310: 3/2 NC, single solenoid, air spring return. For single-acting actuators with mechanical spring return.
• PN 311: 3/2 NC, single solenoid, combined spring return. Requires separate pilot pressure 3–10 bar.
• PN 510 / PN 511: 5/2 single solenoid for double-acting actuators.
• PN 520: 5/2 double solenoid, maintains last position until opposite pneumatic signal is applied.
• PN 531: 5/3 with closed center, for actuators requiring a neutral position with port isolation.

Technical Specifications

Standard versions include NAMUR 1/4” with G 1/4” ports and flow rate of 1250 l/min, and NAMUR 1/2” with G 1/2” ports and 3000 l/min flow. Operating pressure ranges: 1–10 bar, 2–10 bar, or 3–10 bar depending on function and return type. Pilot port is typically G 1/8”.

Selection Criteria for Process Applications

Valve selection is based on:

• Single-acting or double-acting actuator type
• Required fail-safe position
• 3/2, 5/2, or 5/3 logic
• Available pilot pressure
• NAMUR 1/4” or 1/2” interface
• Required valve opening/closing time

Maintenance Considerations

Inspect NAMUR O-rings, instrument air quality, exhaust leakage, full venting of pilot lines, and secure actuator mounting. For double solenoid types, avoid trapped pressure in control lines.

Typical Applications & Media

• Process valve automation (chemical, water treatment, food & beverage)
• Suitable for filtered, lubricated or dry compressed air
• Compatible with standard industrial actuators per VDI/VDE 3845

Standards & Options

• VDI/VDE 3845 NAMUR interface
• Sealing options: NBR, FKM for media compatibility
• Variants for SIL-rated and ATEX environments available