Pneumatically Actuated Valves - Pneumatic pressure-switch | Hafner

Pneumatic Hafner Valves with Integrated Pressure Switch

Hafner SR series are pneumatically actuated valves equipped with an adjustable pneumatic pressure switch. These valves are specified where actuation must be triggered by a pneumatic signal rather than an electrical solenoid. The adjustable setpoint enables sequence control in fully pneumatic circuits, supporting process interlocks and pressure-dependent operations.

Available Versions

• P 311 501 SR: 3/2 monostable valve, universal NC/NO function, G 1/8” ports, flow rate 650 l/min, operating pressure 2–10 bar. Actuation pressure 0–10 bar, switch adjustment range 3–6 bar, pilot port G 1/8”.
• P 411 701 SR: 4/2 monostable valve, G 1/4” ports, flow rate 1250 l/min, operating pressure 2–10 bar, pilot port G 1/8”, switch adjustment 3–6 bar.
• P 411 701 NPT SR: Equivalent to above, with NPT 1/4” ports and NPT 1/8” pilot port.

Operation in Circuit

The integrated pressure switch actuates the valve when pilot pressure reaches the set threshold. This allows use for pressure confirmation, sequence delays, interlocks, or cylinder control based on pressure achieved elsewhere in the circuit.

Selection Criteria

Selection should consider:

• 3/2 or 4/2 function
• NC/NO logic as required by the circuit
• Flow rate: 650 or 1250 l/min
• Available operating pressure
• Switch adjustment range: 3–6 bar
• Thread type: G or NPT
• Required actuation setpoint and switching tolerance

Applications

Suitable for pneumatic machine sequencing, clamp confirmation, position control via pressure, circuit reset, pneumatic panels without electrical signals, and applications requiring actuation based on actual line pressure.

Maintenance

Routine checks should include air cleanliness, setpoint stability, pilot line leakage, switching response, and mechanical condition of the adjustment mechanism. Install filtration upstream in circuits with moisture or particulates.