Valves with NAMUR-Interface - NAMUR accessories | Hafner

Hafner Accessories for NAMUR Valves

Hafner NAMUR accessories are designed for pneumatic rotary actuators used in process valve automation. These components are installed between the valve, actuator, and air supply lines to manage air exhaust, recirculation, manual bypass, or specific fail-safe functions. They support operational safety and process control in accordance with NAMUR standards.

Available Functions

• DSVN 5: Pressure-applied safety valve with NAMUR interface, orifice 5, flow rate 230 l/min P–A/B and 360 l/min A/B–P, pressure range 1–10 bar.
• UB 701: Air recirculation block, G 1/4”, flow 1250 l/min, pressure 1–10 bar.
• SENR 20 / SENR 207: Quick-exhaust NAMUR valves, supply G 1/4”, exhaust G 1/2”, flow 1250 l/min P–2 and 2500 l/min 3–R, pressure 2–10 bar.
• PN 411 721: Pilot-actuated short-cut valve, G 1/4”, 1250 l/min, pressure 1.5–10 bar, pilot 3–10 bar.
• BHN: Block-and-bleed or bypass functions, flow 900–1250 l/min, pressure 1–10 bar, manual force 18 N.
• CBN 700: Control block for butterfly valves with inflatable seat, actuator flow 900 l/min, seal 400 l/min.
• HVRZN 731: Manual pneumatic bypass for positioners, 5/2 or 5/3, G 1/4”, 1250 l/min, 1–10 bar.

Selection Criteria

Selection depends on actuator type, process valve function, fail-safe position, block/bleed requirements, exhaust speed, positioner integration, and NAMUR 1/4” compatibility. Consider media, pressure class, and operational cycles.

Applications and Maintenance

Used with butterfly valves, ball valves, dampers, and actuators (spring-return or double-acting). Maintenance includes inspection of NAMUR O-rings, instrument air quality, exhaust leakage, mounting bolts, and manual safety device operation. Suitable for air, inert gases, and compatible process media.