2/2-way valves
2/2-way valves have two ports and two switching positions (open and closed). They do not have an exhaust function in the closed position (unlike 3/2-way valves). The most common design is the ball seat. 2/2-way valves can be actuated manually, mechanically, or pneumatically.
In other words, 2/2-way valves are simple on/off valves that can be used to control the flow of air or other fluids. They are often used in applications such as pneumatic actuators, irrigation systems, and medical devices.
3/2-way valves
3/2-way valves have three ports and two switching positions. They can be used to set and reset signals, and control the flow of air or other fluids. 3/2-way valves can be actuated manually, mechanically, solenoid, or pneumatically. The actuation method is determined by the specific application.
For example, a manually actuated 3/2-way valve could be used to turn on and off a compressed air supply to a pneumatic actuator. A solenoid actuated 3/2-way valve could be used to control the flow of air to a pneumatic cylinder based on an electrical signal from a PLC.
3/2-way hand slide valve
This manually operated valve has a simple design and is used as an on-off valve, mainly for pressurizing and exhausting control systems or parts of systems. It is operated by sliding the grip sleeve in the longitudinal direction.
In other words, this valve is a simple switch that can be used to turn the flow of air or other fluids on and off. It is operated by manually moving a lever or handle. This type of valve is often used in industrial applications where a simple and reliable way to control the flow of fluids is needed.
3/2-way stem actuated valve
Disc seat mechanically operated valve: This mechanically operated valve uses a disc seat design to create a simple and effective seal. It has a short response time and a large cross section for airflow. Like ball poppet valves, this valve is insensitive to dirt and has a long service life. 3/2-way valves are used to control systems with single-acting cylinders or to actuate control elements.
In other words, this valve is a reliable and efficient way to control the flow of air or other fluids. It is well-suited for applications where dirt and wear are a concern. 3/2-way valves are often used in pneumatic systems, where they control the movement of single-acting cylinders or other actuators.
In a valve with normally open position, port 1 to 2 is open in the normal position. The valve disc seat closes port 3. When the valve stem is actuated, supply port 1 is closed by the stem and the valve disc is lifted away from the seat. The exhaust air can then escape from 2 to 3. When the valve stem is no longer actuated, the return spring returns the valve stem and the valve disc to their initial position. The compressed air flows again from 1 to 2.
3/2-way pneumatic valve
The 3/2-way pneumatic valve is actuated via a pneumatic signal at inlet port 12. Figure below shows a
pneumatically actuated valve with spring return in closed position.
The valve stem is reversed against the return spring by pressurising the control piston at port 12. Ports 1
and 2 are connected. After pilot port 12 is exhausted, the control piston is returned to its initial position by the integrated spring. The disc closes off 1 from 2. The exhaust air from working line 2 can be exhausted via 3. The 3/2-way pneumatic valve with spring return can be used in closed position and open position.
A pneumatically actuated valve can be used as a control element for indirect actuation. The signal for
advancing the cylinder 1A1 is triggered indirectly via the manually operated 3/2-way valve 1S1 that
forwards the control signal to the control element 1V1.
For the open position, ports 1 and 3 simply have to be connected inversely to the closed position. The head of the valve with pilot port 12 can be rotated 180°. The pilot port is then designated 10.
3/2-way solenoid valve
Manual override
Figure below shows two sectional views of a solenoid actuated 3/2-way valve.
- In the normal position, working port 2 is connected to exhaust port 3 by the groove in the armature (see close-up).
- When an electric current flows through the solenoid coil, the magnetic field exerts an upward force on the armature. The armature is lifted against the spring force. The lower sealing seat opens and the flow from pressure supply port 1 to working port 2 is opened. The upper sealing seat closes and shuts off the connection between port 1 and port 3.
- When the solenoid coil is de-energised, the spring force causes the armature to move back to its normal position. The connection between port 2 and port 3 is opened and the connection between port 1 and port 2 is closed. The compressed air escapes through the armature tube and port 3.
Manual override A can be used to open the connection between port 1 and port 2 even if there is no current flowing through the coil of the solenoid. The screw is turned and the eccentric cam actuates the armature. The valve is returned to its normal position by turning the screw the other way
