NAMUR Interface Valves for Actuators
A NAMUR valve mounts directly on a pneumatic quarter-turn actuator and controls the opening and closing of butterfly valves and ball valves. The standardized mounting pattern saves tubing, fittings and leak points. This guide shows how to match function, mode of action and features correctly.
View NAMUR valvesWhat is the NAMUR mounting pattern and why does it save tubing?
The NAMUR mounting pattern is a standardized interface between valve and quarter-turn actuator. Instead of hoses and fittings, the valve bolts straight onto the actuator; the supply and exhaust channels run through a gasket plate in the actuator body. This cuts leak points, assembly time and installed size. The hole pattern and channel layout are unified so valves from different makers fit.
3/2 or 5/2: which valve function fits the actuator?
The valve function follows the actuator's mode of action. A 3/2-way valve controls single-acting actuators with a spring return: it pressurizes to move and exhausts to let the spring drive it back. A 5/2-way valve controls double-acting actuators and alternately pressurizes both chambers. The right choice decides the safe position and the air consumption.
Which features does the valve need in a process environment?
Beyond function and mounting, coil voltage, protection rating and extra features decide the fit. In process plants a manual override, a high protection rating and suitable materials matter. Use clean control air, oiled or unoiled depending on the maker's approval.
- Match the coil voltage to the control system (24 V DC is common in plant builds).
- Choose the protection rating to suit the environment, at least IP65 outdoors or in wash-down.
- Provide a manual override for commissioning and service without a signal.
- Fit a silencer on the exhaust against noise and dirt ingress.
Provide a stable control pressure of 2 to 8 bar through a regulator.
Compare valvesFrequently asked questions
How do I tell whether a valve is NAMUR compatible?
A NAMUR valve has a standardized hole pattern with two fixing bolts and a gasket plate on its underside instead of separate hose ports. The datasheet states NAMUR mounting per VDI/VDE 3845. Also confirm that the channel layout and gasket size match the actuator.
When do I need a 3/2 and when a 5/2 NAMUR valve?
A 3/2-way valve controls single-acting actuators with a spring return and gives a defined safe position on pressure loss. A 5/2-way valve controls double-acting actuators and alternately pressurizes both chambers. The choice follows the actuator's mode of action.
Why is the valve mounted on the actuator instead of on a valve manifold?
Direct mounting saves tubing, shortens response time and reduces leak points. It is robust and easy to service in a harsh process environment. Manifolds pay off more when many actuators are controlled centrally and close together.
Find the right NAMUR valve
Our pneumatics specialists help with valve function, mounting pattern and accessories for your quarter-turn actuators and process valves.
Vetted selection
Recommendations from maker data and field values.
Correct function
3/2 or 5/2 matched to the actuator's mode of action.
Safe position
Fail-safe behaviour and manual override clearly explained.
Expert advice
Pneumatics specialists support your sizing.