ATEX Valves - Pneumatically actuated valves | Hafner

Pneumatically Actuated Hafner ATEX Valves

Hafner P Ex series valves are pneumatically actuated for use in ATEX-classified installations, where actuation is achieved via pilot air rather than an electrical coil mounted on the valve. These valves are specified for pneumatic circuits in hazardous areas, particularly where control signals must remain purely pneumatic or originate from a remote pilot circuit. Typical media include compressed air and inert gases, with compatibility depending on seal material selection.

Available Functions

• P 310 Ex – 3/2 NC, single pilot
  For single-acting cylinders or pneumatic signal switching. Port sizes from G 1/8” to G 1/2”, flow rates 650–3000 l/min, pressure range 1…10 bar or 2…10 bar depending on size. Pilot pressure matches operating pressure.
• P 320 Ex – 3/2 double pilot
  Bi-stable operation with position memory. Valve remains in last switched state until a reverse pilot signal is applied. Pilot pressure 2.5…10 bar.
• P 510 Ex – 5/2 single pilot
  For double-acting cylinders with return via air spring. Flow rates 650–3000 l/min, port sizes G 1/8” to G 1/2”.
• P 520 Ex – 5/2 double pilot
  Bi-stable 5/2 configuration for applications requiring last-position retention without continuous pilot signal.

5/3 Variants

P 531 / P 532 / P 533 Ex models feature spring return to center position:

• Centre closed: isolates actuator ports
• Centre exhausted: exhausts cylinder chambers
• Centre pressurised: supplies both sides of actuator

5/3 versions operate at 1…10 bar with pilot pressure 3…10 bar.

Selection Criteria

Selection should consider 3/2, 5/2, or 5/3 function, fail-safe position, available pilot pressure, actuator flow demand, port threading, and ATEX documentation for the installation.

Maintenance

Inspect pilot lines, trapped pressure, exhaust leakage, silencers, air cleanliness, and dust accumulation on exposed surfaces. Regular checks are recommended for compliance with ATEX and process safety requirements.