Mechanically Actuated Valves - 3/2 Way Valves | Hafner

Hafner 3/2 Mechanical Air Valves

Hafner 3/2 mechanical valves are used for pneumatic signal control or single-acting cylinders where actuation is achieved via mechanical contact, not by solenoid or air pilot. The valve features a supply port, output port, and exhaust port, allowing the actuator to be pressurized or vented depending on the actuation position. These valves are suitable for direct mechanical interface with process equipment.

Actuation Types

Available variants include:

• Stem actuated valves: actuated by axial plunger force.
• Roller lever valves: actuated by a roller lever, suitable for cams or moving mechanical guides.
• Roller lever with idle return: actuation occurs only in one direction of movement.
• Stem actuated valves to pull: actuated by pulling, for specific mechanical arrangements.

Technical Specifications

Connection options: M5, Ø4, G 1/8”, G 1/4”. Flow rates range from 115 to 1250 l/min depending on body type and port size. Operating pressure typically -0.9…10 bar; some versions operate at 2…10 bar. Actuation forces approximately 3.5 N to 17 N. Suitable for filtered, lubricated or non-lubricated compressed air. Temperature range and media compatibility depend on seal material; standard seals are NBR, with FKM available for higher temperature or chemical resistance.

NC / NO Functionality

Many versions can be configured for NC or NO operation, depending on port connections. For safety or sequencing applications, verify the rest position to ensure the output is pressurized or vented as required when not actuated.

Applications

Common uses include:

• cylinder end-of-stroke detection,
• mechanical interlocks,
• pneumatic sequencing without electrical signals,
• packaging and assembly machinery,
• position detection via cam, guide, or moving part.

Maintenance

Inspect for lever or roller wear, mechanical alignment, exhaust leakage, air cleanliness, and spring return function. Excessive lateral load on the lever reduces switching reliability. Periodic checks are recommended for process-critical installations.