| 2/2-Way Directional Valve |
Starts or stops compressed-air flow between two ports. |
2 ports
2 positions
Normally closed or normally open; on/off service.
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Solenoid, pneumatic pilot, manual, mechanical, or spring return. |
Air isolation, blow-off control, simple actuator supply, and vacuum-generator control. |
Port size, flow coefficient, pressure range, response time, seal material, and electrical voltage where applicable. |
Simple construction, easy control logic, and broad availability in compact sizes. |
Cannot independently control two actuator directions; throttling is generally not its intended function. |
| 3/2-Way Directional Valve |
Controls a single-acting cylinder or switches one signal between supply, exhaust, and an actuator port. |
3 ports
2 positions
Normally closed, normally open, or selector configurations.
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Solenoid, pneumatic pilot, pushbutton, roller lever, foot pedal, or spring return. |
Single-acting cylinders, pneumatic signals, air pilot circuits, and small clamps. |
Normal position, exhaust arrangement, flow rate, mounting method, and required actuation force. |
Efficient control of single-acting actuators and control signals with automatic spring return. |
Normally unsuitable for independently driving both sides of a double-acting cylinder. |
| 4/2-Way Directional Valve |
Reverses airflow to operate a double-acting actuator. |
4 ports
2 positions
Supply, exhaust, and two actuator connections.
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Pneumatic pilot, manual, mechanical, or solenoid-assisted actuation. |
Double-acting cylinders, rotary actuators, and applications requiring two fixed motion directions. |
Actuator volume, cycle speed, port arrangement, pressure drop, and control method. |
Provides straightforward forward-and-reverse actuator control with relatively simple circuitry. |
Offers fewer center-positioning options than a 5/3 valve and may require separate exhaust management. |
| 5/2-Way Directional Valve |
Directs supply and exhaust air to opposite sides of a double-acting actuator. |
5 ports
2 positions
One supply port, two actuator ports, and two exhaust ports.
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Single-solenoid spring return, double-solenoid, pneumatic pilot, or manual actuation. |
Industrial automation, pick-and-place equipment, packaging machines, and pneumatic grippers. |
Flow capacity, switching frequency, coil voltage, manual override, mounting style, and exhaust configuration. |
Separate exhaust ports allow better speed control and reduced interaction between actuator chambers. |
Does not provide a dedicated neutral center position; actuator behavior during signal loss depends on the version. |
| 5/3-Way Center-Position Valve |
Controls a double-acting actuator with a selectable center condition. |
5 ports
3 positions
Common centers: closed, exhaust, or pressure.
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Usually double-solenoid with spring-centered spools or pneumatic pilot control. |
Intermediate positioning, holding, controlled stopping, and applications requiring a defined response after signal loss. |
Center-function requirements, actuator load, stopping accuracy, leakage, switching time, and safety strategy. |
Provides a defined center state for holding, exhausting, or pressurizing both actuator chambers. |
A closed center does not guarantee precise position holding because compressed air is compressible and internal leakage may occur. |
| Check Valve |
Allows airflow in one direction and restricts reverse flow. |
2 ports
Non-return
In-line, cartridge, or push-in fitting designs.
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Automatic differential-pressure operation; no external actuator is normally required. |
Backflow prevention, pressure retention, manifold isolation, and protection of pneumatic circuits. |
Cracking pressure, reverse leakage, forward flow capacity, installation direction, and temperature range. |
Compact, fast, and energy-efficient with simple automatic operation. |
Can create unwanted pressure trapping if installed without a suitable exhaust or isolation arrangement. |
| Pilot-Operated Check Valve |
Blocks airflow in a normal condition and releases it when a pilot signal is applied. |
3 or more ports
Load-holding
Often installed close to an actuator port.
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Pneumatic pilot pressure, sometimes with manual override. |
Holding a cylinder during pauses, reducing unintended movement, and supporting load-control circuits. |
Pilot ratio, minimum pilot pressure, actuator load, residual pressure, leakage, and response time. |
Can help prevent unexpected actuator movement when the control valve changes state. |
It is not a substitute for a complete machine safety system or a mechanically rated load-holding device. |
| Flow-Control Valve |
Regulates airflow to adjust actuator extension or retraction speed. |
Meter-in
Meter-out
Needle type
Fixed or adjustable restriction, often with a reverse-flow check.
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Manual adjustment; some systems use proportional or electronically controlled versions. |
Cylinder speed adjustment, soft motion, cycle-time control, and sequencing. |
Required flow range, adjustment resolution, pressure drop, installation direction, and load stability. |
Provides a cost-effective method for tuning actuator speed without changing the main directional valve. |
Speed can vary with load, supply pressure, temperature, and air compressibility; incorrect adjustment may cause unstable motion. |
| Quick Exhaust Valve |
Exhausts air directly near the actuator instead of routing it back through the directional valve. |
3 ports
Supply / actuator / exhaust
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Automatic pressure differential operation. |
Increasing cylinder speed, reducing exhaust backpressure, and shortening pneumatic response time. |
Exhaust capacity, silencer restriction, port size, mounting location, and noise level. |
Can improve actuator response and reduce exhaust-line pressure losses. |
May increase exhaust noise and can cause performance issues if the silencer is undersized or contaminated. |
| Shuttle Valve |
Passes the higher-pressure signal from either of two inputs to one output. |
3 ports
OR logic
Two inputs and one output.
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Automatic pressure selection from either pneumatic input. |
Two-hand control logic, alternate signal sources, pneumatic OR circuits, and redundant command paths. |
Switching pressure, leakage, response time, flow capacity, and compatibility with the control logic. |
Combines two pneumatic signals without requiring electrical logic or a powered control system. |
It does not provide AND logic; residual pressure and backflow must be considered in circuit design. |
| Pressure Regulator |
Reduces and maintains downstream pressure below the inlet pressure. |
2 main ports
Relieving or non-relieving
May include a gauge port and integrated filter.
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Mechanical spring-and-diaphragm or piston adjustment; electronically controlled versions are also available. |
Protecting components, setting actuator force, stabilizing control pressure, and dividing a system into pressure zones. |
Inlet and outlet pressure, flow demand, regulation accuracy, relieving function, gauge range, and contamination tolerance. |
Improves pressure stability and enables different operating pressures within one pneumatic system. |
Cannot raise downstream pressure above inlet pressure; regulation accuracy changes with flow and supply conditions. |
| Pressure-Relief Valve |
Releases air when pressure exceeds a preset safety or protection threshold. |
Inlet and exhaust
Overpressure protection
Direct-acting or pilot-assisted designs.
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Automatic spring-loaded operation or pilot-assisted operation. |
Protecting receivers, manifolds, actuators, and pneumatic equipment from excessive pressure. |
Set pressure, discharge capacity, reseat behavior, allowable leakage, temperature, and applicable regulations. |
Provides an automatic method of limiting pressure in a pneumatic section. |
Must be correctly sized and installed; it does not replace required machine guarding, isolation, or lockout procedures. |
| Proportional Pneumatic Valve |
Varies pressure or flow continuously in response to an electrical command. |
Continuous control
Analog or digital input
Pressure, flow, or directional proportional designs.
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Electronic command using voltage, current, fieldbus, or dedicated controller. |
Force control, tension control, variable-speed motion, pressure regulation, and automated process control. |
Control resolution, hysteresis, repeatability, response time, signal type, air quality, and calibration requirements. |
Enables finer control than basic on/off valves and supports automated process adjustment. |
Higher system complexity and cost; performance depends strongly on clean, dry air and correct commissioning. |
| Vacuum Switching Valve |
Connects, isolates, or vents a vacuum circuit while controlling the workpiece side. |
2/2 or 3/2
Vacuum service
Some versions include blow-off or vacuum-break functions.
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Solenoid, pneumatic pilot, or integrated electronic control. |
Vacuum cups, material handling, packaging, pick-and-place systems, and vacuum grippers. |
Vacuum level, leakage, response time, blow-off flow, port size, and compatibility with the vacuum generator. |
Supports rapid gripping and release when matched with an appropriately sized vacuum circuit. |
Contamination, porous workpieces, and excessive leakage can reduce gripping performance and increase air consumption. |
| Solenoid Valve |
Uses an electrical coil to switch or pilot pneumatic airflow. |
2/2, 3/2, 4/2, or 5/2
Direct or pilot operated
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Electrical coil controlled by a PLC, relay, sensor, or other automation controller. |
Automated machinery, process equipment, packaging lines, robotics, and general pneumatic control. |
Coil voltage, power consumption, duty cycle, response time, ingress protection, connector type, and manual override. |
Easy integration with modern electrical control systems and reliable repeatable switching. |
Requires suitable electrical power and suppression; pilot-operated designs may need a minimum pressure differential. |
