Pneumatic Solenoid Valve Diagrams

Understanding the diagrams associated with pneumatic solenoid valves is crucial for anyone involved in designing, maintaining, or troubleshooting pneumatic systems. Pneumatic solenoid valves control air or gas flow in these systems, enabling precise operation of machinery and equipment.

Pneumatic solenoid valves use electromagnetic solenoids to control the opening and closing of valve ports. When an electrical current passes through the solenoid, it generates a magnetic field that moves a plunger or armature, thereby controlling air or gas flow. These valves are widely used in applications ranging from simple air control in HVAC systems to complex automation processes in manufacturing.

Table of contents

• Pneumatic solenoid valve diagrams
• Types of pneumatic solenoid valves
• Pneumatic solenoid valve applications
  • Single-acting cylinders
  • Double-acting cylinders
  • Speed control
  • Manual valve for work cylinder and clamp cylinder
  • Cylinder extends and retracts automatically
  • Cylinders extend sequentially and retract automatically
  • Cylinder actuation from two different locations
  • Cylinder floats at any position
• FAQs

Pneumatic solenoid valve diagrams

Diagrams of pneumatic solenoid valves visually represent their internal structure and operation. These diagrams are essential for several reasons:

• Design and installation: Engineers and technicians use these diagrams to accurately design and install pneumatic systems.
• Maintenance and troubleshooting: Understanding the diagrams helps diagnose issues and perform maintenance tasks efficiently.
• Safety: Proper interpretation of valve diagrams ensures that systems operate safely, preventing accidents and equipment damage.

How to read a diagram

If the diagram is vertical, the bottom square shows the unactuated state (Figure 2 labeled B), and the top square shows the actuated state (Figure 2 labeled A). If the diagram is horizontal, the right square is the un-actuated state, and the left square is the actuated state. The arrows show the direction of airflow, and the shapes that look like a T on its side show a port that is not being used in the valve's current state or is plugged entirely.

Other common symbols on a diagram are seen in Table 1. Learn more about symbols used in pneumatic system diagrams by reading our pneumatic system symbols overview.

Diagram numbers

Throughout this article, pneumatic diagrams are marked with numbers 1-5. They mean the following:

1. In: Air flows into the valve at this port
2. Out: Air flows out of the valve at this port to another system component. Or, air flows into this port from another system component to be exhausted through an exhaust port.
3. Exhaust: Air exhausts at this port after returning to the valve from another system component
4. Out: Air flows out of the valve at this port to another system component. Or, air flows into this port from another system component to be exhausted through an exhaust port.
5. Exhaust: Air exhausts at this port after returning to the valve from another system component

Table 1: Common symbols indicating pneumatic solenoid valve actuation and return

Name	Symbol	Explanation
Spring return		Diagonal lines at the top or bottom of the valve indicate a spring return
Air pilot		A rectangle with a triangle on one side represents an air pilot that assists in valve actuation
Manual actuation		The rectangle and semicircle on top of the valve indicates that the valve is manually actuated
Limit switch valve		The circle and two lines on top of the valve indicate it is acting as a limit switch valve.

Normally open vs normally closed valve diagrams

The unactuated state portion of the diagram helps a reader understand if the valve is normally open or normally closed. A normally open valve will show air moving from left to right when unactuated (Figure 3 left) and a normally closed valve will show air moving from right to left when unactuated (Figure 3 right).

Types of pneumatic solenoid valves

Pneumatic solenoid valves come in various types, each suited for specific applications. Table 2 shows common types of pneumatic solenoid valves, including 2 position pneumatic solenoid valve diagrams and 3 position pneumatic solenoid valve diagrams.

Table 2: Types of pneumatic solenoid valves and their diagrams

Valve type	Explanation	Diagram
2/2-way valves	Two ports and two positions. Typically used for simple on/off control of air flow.
3/2-way valves	Three ports and two positions. Typically used to control single-acting cylinders.
5/2-way valves	Five ports and two positions. Typically used to control double-acting cylinders.
5/3-way valves	Five ports and three positions, providing more complex control options.

Pneumatic solenoid valve applications

Pneumatic solenoid valves are suitable for numerous applications. This section will provide pneumatic solenoid valve circuit diagrams for many applications to help readers understand how different components connect.

Single-acting cylinders

3/2-way directional control valves can operate single-acting pneumatic cylinders. Figure 4 shows a normally closed valve operating with a cylinder. When unactuated, the spring in the cylinder returns it to its original position, and air vents through the valve's exhaust. When actuated, air flows into the cylinder and pushes against the spring force, extending the cylinder's rod.

Double-acting cylinders

As seen in Figure 5, double-acting cylinders are controlled by 5/2-way valves capable of having air flow and exhaust ports whether the valve is actuated or unactuated. Learn more in our single acting vs double acting pneumatic cylinders article.

Speed control

Pneumatic cylinder applications that require precise positioning, smooth operation, or synchronization with other machine components, such as in automated assembly lines, material handling systems, and robotics, may need speed control of the extension and retraction of the piston rod. Figure 6 demonstrates how installing flow control fittings (e.g., needle valves with push-in fittings) between the pneumatic solenoid valve and pneumatic cylinder can accomplish this. Figure 7 demonstrates how installing these needle valve fittings at the valve's exhaust ports can accomplish the same.

Manual valve for work cylinder and clamp cylinder

Work cylinders and clamp cylinders can be controlled so they work in conjunction with one another. The flow control delays the extension of the work cylinder until the clamp cylinder is properly positioned. The force of the clamp cylinder is restricted to match the load of the work cylinder until the work cylinder is fully extended. When the manual valve is reset, the work cylinder will retract before the clamp cylinder is released.

Cylinder extends and retracts automatically

Using a limit valve (e.g., a pneumatic solenoid valve with a roller or a pneumatic whisker valve) can automatically retract the pneumatic cylinder. As seen in Figure 9, activating the manual valve causes the cylinder to extend, triggering the limit valve, which then resets the manual valve, retracting the cylinder.

Cylinders extend sequentially and retract automatically

Multiple limit valves can be used to set up a sequence of pneumatic cylinders that extend in sequence and then automatically retract when the system is reset. Figure 10 shows how this is accomplished. When manually initiated, this circuit will cause the two cylinders to extend sequentially and then automatically retract, with the manual valve returning to its original position during the process.

Cylinder actuation from two different locations

Figure 11 demonstrates a circuit that uses two manually actuated pneumatic solenoid valves. Although the two valves are in different locations, actuation of either valve will cause the pneumatic cylinder to move to its other position.

Cylinder floats at any position

A 5/3-way pneumatic solenoid valve can extend or retract a pneumatic cylinder's piston rod and in its third position (center position) the cylinder does not extend or retract. This means the position of the cylinder can be controlled to float along any point in its path, as seen in Figure 12.

FAQs

What is a pneumatic solenoid valve diagram?

A pneumatic solenoid valve diagram is a schematic representation showing the connections of a solenoid valve used to control air or gas flow.

What is a 2 position pneumatic solenoid valve diagram?

A 2 position pneumatic solenoid valve diagram illustrates a valve with two stable states, showing how the solenoid shifts the valve between these positions to control air flow.