The actuation component that causes the pneumatic valve to open or close might be accomplished in any of several ways, including manually, electrically via a solenoid valves or motorized actuator, or pneumatically. The key concept to note in this case is that it is pressurized air or gas that is being controlled and which is flowing through the valve ports in the pneumatic system.http://www.wemedrive.com/contr....ol-component/pneumat