Page 55 - PNEUMATIC SYSTEM INSTRUMENT

FOUR-WAY AND FIVE-WAY, TWO-POSITION VALVES

4(A) 2(B)

1(P)
5(R) 3(S)

Figure 7.5: Four-way and five-way, two-position valves schematic

symbol

Begin with four or five ports with two or three positions. A two-

position valve has two distinct flow paths in each position to actuate

and reverse cylinders, rotary actuators, or bidirectional motors. The

spool directs flow from the pressure port while the other actuator port

exhausts to atmosphere at the same time.

The five-port version of the two-position, five-way valve has five

individual ports which provide various valve configurations such as

two different exhaust or pressure ports. In the latter case, for

example, the valve might supply high pressure to actuate a cylinder

and provide high clamping force but deliver lower pressure (from a

regulator) to release the clamp. Using lower pressure conserves

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