Compressed air is delivered from the mains to port 1. Port 2 is
connected to chamber 3 which, in turn, is connected to the
atmosphere by a port (not shown). At the same time, air is
delivered through channel 5 to ball valve 8. Channel 6 is connected
to the atmosphere through holes drilled in armature 7
and through hole 9. When coil 10 is energized, the armature is
pulled into the electromagnet and moves downward, overcoming
the resistance of the spring. In the first part of this motion,
the ball of valve 8 shuts off the central passage in the armature,
disconnecting channel 6 from the atmosphere. In further motion
of the armature, the ball of valve 8 is pushed downward, allowing
air from channel 5 to enter channel 6. The pressure of the
compressed air shifts plunger 4 downward, overcoming the
resistance of the spring, and air from port 1 flows through
port 1, which is disconnected from chamber 3. When coil 10
of the electromagnet is de-energized, armature 7 is raised by
its spring, ball valve 8 closes and channel 6 is connected to the
atmosphere. Then plunger 4 is returned by its spring to the
position shown. Directional valves of this type are applied
to control one way actuators (operating cylinders or devices).
$4312$SmE,FC$