Pneumatically Actuated Valves - 3/2-way valves | Hafner

Pneumatically Actuated Hafner 3/2 Valves

Hafner 3/2 pneumatically actuated valves are specified for circuits where switching is controlled by pilot air rather than solenoids. These valves are suitable for pneumatic logic, interlocks, auxiliary machine commands, and single-acting cylinder control. The range includes in-line versions and G-series for both in-line and manifold mounting.

Available Functions

• P 310: Monostable 3/2, NC, air spring return. Port sizes from M5 to G 3/4”, flow rates 180–6000 l/min, operating pressure up to 10 bar depending on size.
• P 311: Monostable with mechanical spring, universal NC/NO function. Requires pilot pressure 3–10 bar, available from G 1/8” to G 3/4”.
• P 320: Bistable 3/2 with double pilot actuation. Maintains last position until an opposing pneumatic signal is applied.
• P 322: Bistable with dominating piston at port 12, for circuits where one pilot command must take priority.

Selection Criteria

Selection is based on required flow, available line pressure, pilot pressure, NC/NO function, port threading, and memory requirements. For low-demand signals, M5 or G 1/8” is sufficient. For larger actuators, consider G 1/4”, G 3/8”, G 1/2”, or G 3/4”.

Applications

Used in pneumatic panels without local electrical control, packaging machinery, assembly lines, safety interlock circuits, reset functions, and auxiliary pneumatic commands.

Maintenance

Check air cleanliness, exhaust leakage, pilot tubing, response time, silencers, and seal wear. For bistable units, ensure both pilot lines vent correctly. Regular inspection is recommended for reliable operation in industrial environments.