2-1.Directional control valve
2-1.Directional control valve
To operate the drive unit (actuator), it is necessary to switch the air flow by inputting or outputting air.
valve that control (switch) the flow direction of compressed air are called directional-control valve.
In pneumatic circuits, directional control valve are used to
(1) switch the flow direction of air supply and exhaust to actuators such as air cylinders,
(2) supply and shut off air, and control the selection and switching of pneumatic circuits.
Directional-control valve
Directional control valve can be classified into the following categories.
Classification by number of ports
Classification by number of ports
Ports refer to piping connection openings.
The purpose of use varies depending on the number of ports.
The number of ports and the purpose of control are as follows.
(1) 2-port
The 2-ports have 2 piping connections and are used to simply stop or channel the flow of fluid.
Example: Air blow, etc.
CKD's Leading Products
(2) 3-port
The 3-port solenoid valve has 3 piping connections for fluid supply and exhaust. Example: Control of single acting cylinders, etc.
CKD's Leading Products
(3) 4-port/5-port
It has 4 or 5 piping ports to supply and exhaust fluid simultaneously. Mainly used to control double-acting air cylinders.
The 5-port valve has separate exhaust ports for two output ports.
The 4-port valve has one exhaust port, but the functionality is the same.
CKD's Leading Products
Pilot operated 3, 5-port valve 4GA/BR, M4GA/BR, MN4GA/BR Series 
Classification by Sealing Method
There are two types of sealing methods for sealing the air flow path of directional control valve: metal-to-metal "metal seal" and "elastic seal" that uses rubber or other elastic materials.
