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DIRECTIONAL CONTROL VALVE (DCV)








               A directional control valve, (DCV) used to convert energy stored in the

               compressed air into mechanical motion and to move actuators into


               various  positions.  Alternate  tools  include  linear  piston,  rotary


               actuators, air tools, expanding bladders, etc.




               A directional control valve determines the flow of air between its ports


               by opening, closing, or changing its internal connections. The valve is

               described in term of:





                            The number of ports.


                            The  number  of  switching  positions,  its  normal  (not

                              operate) position.


                            The method of operation.




               The first two points are normally expressed in terms 2/2, 3/2 or 5/2.


               The Figure 7.1 below, relates to the number of ports (excluding pilot


               ports) and the second to the number of positions.



















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