The word, NAMUR, somewhat a misnomer, is an acronym for the User Association of Automation Technology in Process Industries, and serves as a standard for automated valve technology.  Standard interfaces for actuator mountings keeps solenoid and installation costs down. A Namur solenoid valve, therefore, is directly mounted to pneumatic actuator inlet/outlet ports.

The function of a NAMUR solenoid valve is to control media flow: the valve itself is controlled by an electric solenoid, which opens or closes the valve, by controlling the amount of air–via a pilot–to the pneumatic actuator. A pneumatic actuator converts energy–compressed air–into motion.  The solenoid and actuator work in tandem to control flow speed, flow amount, and flow direction.  Likewise, the valve is operated in either the normally closed, or normally open position.

Solenoid valves are available in several configurations, including 3 way and 4 way. A 3 way solenoid valve typically consists of 1 inlet, 1 outlet, and 1 exhaust port, and 2 seats for fluid control.   A 4 way solenoid valve utilizes 4 or more ports (2 inlets, 1 outlet, 2 exhausts and 2 seats), and are commonly applied for operating double acting rack and pinion actuators.