What does the designation 4/2 mean for a pneumatic valve and which ports are typically present?

What does the designation 4/2 mean for a pneumatic valve and which ports are typically present?

• A. A four-port, two-position valve with ports P, T, A and B.
• B. A two-port, four-position valve with supply and outputs.
• C. A three-port, two-position valve with P, A, R.
• D. A five-port, three-position valve.

Answer: (A)

In pneumatics, the 4/2 label describes two things about the valve: the number of ports and the number of positions. Four ports means there are P, T, and two work ports (A and B). P is the pressure supply, T is the exhaust (tank) port, and A and B are the two actuator connections. Two positions mean the valve has two distinct routing configurations. In one state, air from P goes to one work port (P to A) while the other work port exhausts (B to T). In the opposite state, P connects to the other work port (P to B) and the first work port exhausts (A to T). This is what lets a double-acting actuator extend and retract. The actuation method (solenoid, spring, lever) isn’t specified by the 4/2 designation itself—only the port count and the number of positions. Thus, the configuration described—four ports with P, T, A, and B in a two-position valve—is the correct interpretation.

In pneumatics, the 4/2 label describes two things about the valve: the number of ports and the number of positions. Four ports means there are P, T, and two work ports (A and B). P is the pressure supply, T is the exhaust (tank) port, and A and B are the two actuator connections.

Two positions mean the valve has two distinct routing configurations. In one state, air from P goes to one work port (P to A) while the other work port exhausts (B to T). In the opposite state, P connects to the other work port (P to B) and the first work port exhausts (A to T). This is what lets a double-acting actuator extend and retract.

The actuation method (solenoid, spring, lever) isn’t specified by the 4/2 designation itself—only the port count and the number of positions. Thus, the configuration described—four ports with P, T, A, and B in a two-position valve—is the correct interpretation.