Page 58 - PNEUMATIC SYSTEM INSTRUMENT

Figure 7.6: Graphics symbols for most common centre positions of

five-ported, five-way directional valves

The pressure-centre type of valve might be used to alternately control

the motion of two or three groups of single acting cylinders. When the

valve is in its centre or neutral position, pressure is directed to both

cylinders, causing both to extend. If the valve is shifted to either

extreme position, one-cylinder group retracts while the other remains

extended. When the valve is shifted in the opposite direction, the

motion of the cylinder groups is reversed.

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