What is the 4-way Solenoid Valve?

The solenoid valve supplying air to that actuator must have four ports: one for air supply (P), one for exhaust (E), and two for the cylinder ports (typically labeled A and B), so that to make a pneumatic actuator move two different directions. These valves are required for double-acting cylinders because they actually switch the direction of airflow from going in the bottom of the cylinder inlet to going in the top of the cylinder’s other port. This helps the cylinder to open and close very rapidly. This type of valve is much more useful when different types of fluid being mixed with each other in a certain fixed ratio.