What is a pneumatic solenoid valve?
A pneumatic solenoid valve is a basic automation component that uses electrical signals to control the flow of compressed air whether on or off and in what direction.
Pneumatic solenoid valves play a key role in controlling the flow of compressed air or process gases. To understand their operating principles, we must first understand their components and actuation functions.
Components and Parts of a Pneumatic Solenoid Valve
The first step in understanding pneumatic solenoid valves is to understand their components.
A pneumatic solenoid valve includes two parts: an electrical section and a mechanical section. The combination of these components enables precise directional control of gas flow.
Electromechanical device consists of a motor, switches, and other components used to precisely regulate the mechanical movement of mechanical devices, cylinders, actuators and other pneumatic components that combines the electrical signal with the mechanical action inside the valve.
A typical valve body consists of a solenoid, a plunger and multiple orifices, the number of which varies depending on the desired flow control.
Pneumatic solenoid valves are most commonly classified in two ways.
operating position
| Type | 2/2-way valve | 2/3-way valve | 2/5-way valve |
| Ports | One inlet P and one outlet A | One inlet P, one outlet A and one exhaust port R | One air inlet P, two air outlets A and B, and two exhaust ports R and S |
| Normal work | Opening and closing of the gas | Control the extension and retraction of single-acting cylinders | Switch the air circuit to drive the cylinder to reciprocate |
| How it works | When the power is on, P→A supplies air, pushing the cylinder to move. When the power is off, A→R exhausts air, and the cylinder resets under the action of the spring. | When the power is on, P→A supplies air, B→S exhausts air, and the cylinder moves in one direction. When the power is off, P→B supplies air, A→R exhausts air, and the cylinder moves in the opposite direction. |
operating mode
they can be divided into direct-acting and pilot-operated types.
Direct-acting types directly use electromagnetic force to drive the valve core that has a simple structure but low power consumption and is typically used for small-diameter valves.
Pilot-operated types use air pressure itself to assist in moving the main valve core that are more common in industry. The electromagnetic force only controls a small pilot valve, allowing a low-power coil to control large flows.
The core operating principle remains the same regardless of classification: when the solenoid valve coil is energized, the current generates a magnetic field within the coil. A magnetic field drives an internal plunger (or valve core) to move that open or close the valve that controls the flow path of compressed air that either allow air to flow smoothly through the valve or blocking it. This extremely fast action makes pneumatic solenoid valves ideal for controlling high-speed processes in automation systems.
Choosing the Right Pneumatic Solenoid Valve
The pressure range of the selected valve must be able to withstand the system’s operating pressure. This means its flow capacity must match the system requirements: too low a pressure value will limit performance, while too high a pressure value will reduce efficiency.
The valve’s voltage must also be consistent with the site power supply to ensure proper operation.
The material selection of the solenoid valve is also important: if installed in a corrosive environment or extreme temperatures, corrosion-resistant materials (such as stainless steel) should be used to ensure the valve’s longevity.
Common faults
Conclusion
Solenoid valves control cylinders, fluid power motors or large industrial valves in fluid power pneumatic and hydraulic systems. Automatic irrigation sprinkler systems also use solenoid valves with automatic controllers. Household washing machines and dishwashers use solenoid valves to control the flow of water into the machines that can be used in a wide range of industrial applications including general on/off control, calibration and test benches, pilot plant control loops, process control systems, and various OEM applications. If you still hesitate, contact us to learn more.