Pneumatic symbols

What is a pneumatic symbol?

Pneumatic symbols are an effective way to describe the functionality and operation of often complex pneumatic systems. There is a set of symbols that represent pneumatic components and functions, including valves, cylinders, pressure sources, air filters, hoses, and much more. The symbols are used to create schematic representations of pneumatic systems, facilitating design, communication, and troubleshooting.
To maintain a common view of drawings with pneumatic components, standards are in place that establish standardized symbols used in pneumatic diagrams and drawings. The most widely recognized standard is ISO 1219-1. In addition, there is the "Japanese Industrial Standard (JIS)", but in most cases the symbols are identical to each other.
It is important for technicians and engineers working in the field of pneumatics to be familiar with the ISO 1219-1 standard and its symbols, as they are needed in the design and documentation of pneumatic systems. The standard helps ensure that all parties involved can understand and interpret pneumatic diagrams correctly.

Quicklinks: Symbols for pneumatic cylinders | Symbols for pneumatic valves | Line symbols| Common components in pneumatic systems | Symbols for direction valves

Symbols for Pneumatic Cylindres

Pneumatic sylindres convert air pressure to mechanical movement and are used to drive different types of appclications for moving and placing in pneumatic systems.

Single acting load returns

A single-acting pneumatic cylinder with load return can perform work such as moving a load when pressure is applied. After the pressure is released, the piston returns to its original position with the help of external force or a spring.

Single acting spring returns

Single-acting pneumatic cylinders with spring return are used in many industries. They perform movement in one direction and return to the original position with a built-in spring when pressure is released. The strength of the spring varies depending on the requirements.

Double acting non-cushioned

Double-acting pneumatic cylinders with spring return are used in many industries. They perform movement in two directions and return to the original position with a built-in spring when pressure is released. The strength of the spring varies depending on the requirements.

Double acting adjustable cushions

The symbol represents a type of pneumatic cylinder that is used to generate motion in two directions and is equipped with adjustable damping mechanisms. These cylinders allow for fine-tuned control over the speed of movement by regulating the flow of air in and out of the cylinder.

Single acting load returns

The symbol represents a type of pneumatic cylinder that is used to generate motion in two directions and is equipped with adjustable damping mechanisms. These cylinders allow for fine-tuned control over the speed of movement by regulating the flow of air in and out of the cylinder.

Cylinder Spring Return


The symbol­ re­presents a pneumatic cylinder that is used to generate linear motion and has a spring mechanism to return to its original position after pressure has been released. When compressed air is applied to one side of the piston, the piston moves outward, and when the pressure is released, it returns to its original position.

Cylinder Double Acting (Double Rod)

The symbol represents a pneumatic double-acting cylinder with double bars. The cylinder can generate linear motion in both directions. When compressed air is applied to one side of the piston, it moves outwards, and when the pressure changes and is applied to the other side, the piston moves in the opposite direction.

Cylinder Double Acting (Single Fixed Cushion)

The symbol represents a pneumatic cylinder that is double-acting and has a simple fixed damping that controls movement at the end points of the stroke. This type of cylinder is used when it is necessary to avoid collisions or excessive speed at the end of the movement.

Cylinder Double Acting (Two Adjustable Cushions)

The symbol represents a pneumatic cylinder that is double-acting and has two adjustable dampers to control movement at the end points of the stroke. These adjustable cushions allow you to adapt the movement to specific needs.

Symbols for Pneumatic Valves

Pneumatic valves are components that control the flow of air within pneumatic systems, and they can be used to regulate, stop, or direct the movement of air.

Safety Valve

The safety valve is a critical component of pneumatic and hydraulic systems. Its purpose is to protect the system from overload by regulating and relieving pressure at dangerous levels. It ensures that the system's pressure does not exceed its rated capacity, reducing the risk of damage and system failure.
Contrary to the relief valve, this component offers immediate pressure release, where as a relief valve is commonly used for continuous operation prohibiting excessive pressure buildup.

Flow Control

Flow control involves regulating and controlling the flow of gas or liquid in a system to achieve the desired speed, direction or amount.

Check Valve

Single-acting pneumatic cylinders with spring return are used in many industries. They perform movement in one direction and return to the original position with a built-in spring when pressure is released. The strength of the spring varies depending on the requirements.

Check Valve (Spring Loaded)

The symbol represents a pneumatic check valve equipped with a spring mechanism that keeps the valve closed until a sufficient pressure is reached. The purpose is to prevent air from flowing backwards into the system. When the pressure on one side of the valve becomes high enough to overcome the spring force, the valve opens and allows the flow to pass. When the pressure decreases, the valve automatically closes to prevent backward flow.

Line Symbols

 Line symbols are important in pneumatic diagrams and drawings to indicate direction, couplings and flow streams for air or pressure. 

 2 Lines joined

The symbol represents two connected pneumatic lines within a system, which can be connections or connections between components. The symbol indicates a physical coupling, which is important for transferring compressed air and controlling pneumatic functions.

3 lines joined

The symbol shows the connection of three pneumatic lines within a system. The symbol indicates where three overhead lines meet, often in pneumatic diagrams to illustrate how the airflow is distributed among different components. This helps to clarify the path of compressed air and its interaction with the parts of the system.

Lines Crossing

The symbol indicates that two or more pneumatic lines intersect within a system. It shows where the lines intersect and how the airflow is distributed between the parts of the system.

Double acting adjustable cushions

The symbol represents a type of pneumatic cylinder that is used to generate motion in two directions and is equipped with adjustable damping mechanisms. These cylinders allow for fine-tuned control over the speed of movement by regulating the flow of air in and out of the cylinder.

Main line

The symbol indicates the main line in a pneumatic system, distributing compressed air to the various components of the system.   The symbol shows where the main line is connected and how it is integrated in the system.  

Common symbols for Pneumatic Components

These frequently used symbols for pneumatic components or units are used in pneumatic flow sheets or diagrams, indicating how the various components are connected and operate in the system.

Accumulator

The symbol indicates a pneumatic component which stores compressed air. It equalizes variations in the pressure and provides extra air when needed.  

Air dryer

The symbol represents a pneumatic component used to remove moisture from the compressed air in a pneumatic system. Any moisture in the compressed air can cause problems like corrosion and reduced performance.  

Air motor 
(One direction flow)

An air motor is a pneumatic component which converts the energy of compressed air to mechanical movement. The symbol represents an air motor which only operates in one mechanical direction restricted by the flow. 

Air motor 
(Two direction flow)

The symbol represents a pneumatic air motor that can handle flow in two directions. Air motors with bidirectional flow are useful in applications where movement in both forward and backward directions is required, providing operators with greater flexibility in controlling mechanical systems.

Compressor

The symbol represents a pneumatic compressor used to compress and deliver air to a pneumatic system. A compressor takes in ambient air, compresses it, and delivers it at higher pressure to a pneumatic system. The increased air pressure is then used to power pneumatic actuators, valves, and other pneumatic components.

Differential pressure

The symbol is used to indicate when measurement or control of the differential pressure between two points within a pneumatic system is required.

Direction of Flow

The symbol is used to indicate the direction of air or fluid flow within a pneumatic system. It helps explain how different components and valves affect the flow direction and in which direction the air or fluid will move as it passes through the marked component.

Control- or Exhaustline

The symbol indicates a line or conduit connected to the outlet of a valve or control unit. It shows where the outgoing air flows from a component.

Filter

The symbol represents filters used to purify air or gas circulating within the system by removing particles and contaminants. This helps ensure that the air used in pneumatic systems is clean and free from debris that could damage components or affect system performance.

Filter (Automatic Drain)

The symbol represents a pneumatic filter component that not only purifies the air within the system by removing particles and contaminants but also features an automatic draining function. The automatic drainage is used to periodically remove accumulated condensate and other fluids from the filter.

Filter (Manual drainage) 

The symbol represents a pneumatic filter component that requires manual draining to remove accumulated condensate and other fluids from the filter regularly, in order to maintain the filter's efficiency.

Fixed restriction

The symbol represents a pneumatic component used to restrict airflow to a fixed level. This component is typically part of a pressure or flow regulation device and is used to control the speed or force of a pneumatic actuator. The symbol is usually accompanied by an arrow indicating the direction of airflow through the fixed restriction and a component that regulates the amount of airflow.

Lubrication

The symbol represents a pneumatic lubrication unit used to add lubricant, usually oil, to pneumatic systems. Lubricators reduce friction and wear on pneumatic components, helping to extend their lifespan and maintain proper function.

Lever

The symbol represents a lever used to manually activate or control a component within a pneumatic system. Levers are often used to manually operate valves, open or close airways, or adjust other parameters within pneumatic systems.

Lever operated 
(Spring Return)

The symbol represents a pneumatic valve or device that is controlled using a lever mechanism and features a spring return function. This type of valve is used to regulate airflow through the system.

External Pilot

The symbol represents a pneumatic valve or device that is controlled using an external pilot air stream. Pilot air is often used to control or activate functions such as valves and cylinders. This can be useful when you want to activate or deactivate a pneumatic component from a remote location using a pilot air signal.

Internal Pilot

The symbol represents a pneumatic valve or device that is controlled using an internal pilot air stream. Internal pilot provides independent control of pneumatic components without relying on external pilot signals or pressure sources.

Solenoid ​

The symbol represents a pneumatic or electric solenoid used to control a valve or another pneumatic component. A solenoid is a device that converts electrical energy into mechanical motion and is commonly used to open or close valves within pneumatic systems.

Detent

The symbol represents a mechanical device used to establish a fixed position in a pneumatic or mechanical component. It functions as a lock, providing clear positioning or preventing unintentional movement.

Spring

The symbol represents a spring in a pneumatic system. Springs are used to generate a return force and restore a component to its original position.

Mechanical

The symbol is used to indicate when mechanical components are present and have a specific function in the system.

Foot Operated

The symbol represents a mechanical component or device that is activated by a foot pedal.

Push Button

The symbol represents a push button used to activate or deactivate a component within a pneumatic system.

Manual

The symbol represents manual control or operation. It can be used for various manual handles, levers, knobs, or dials that are used to adjust or regulate pneumatic components or processes.

Directional Control Valves Symbols

Directional control valves can shift airflow between different directions and ports within a pneumatic system. The symbols show how the valve operates and how airflow can be controlled, including the number of ports and the various positions of the valve. These symbols are used to create diagrams and drawings that describe pneumatic systems and their functions.

5/3 Valve

3-position, 4-way, 5 ported Open Center
The symbol represents a directional control valve with 3 positions, 4 paths, and 5 ports, featuring an open center configuration and an exhaust center position. In an open center configuration, all ports are interconnected, allowing continuous airflow when the valve is in its center position. When the valve shifts positions, certain ports close while others open, altering the direction of airflow within the system.

5/3 Valve

3-position, 4-way, 5 Ported Pressure Center 
The symbol represents a directional control valve with 3 positions, 4 paths, and 5 ports, configured with a pressure center. In the pressure center position, the valve is neutral, with no connections to any port. When the valve shifts positions, it directs the airflow from one or more of the five ports.

5/3 Valve

3-position, 4-way, 5 Ported Closed Center
The symbol represents a directional control valve with three positions and five ports, where the center position is closed and isolated from the other ports. When the valve shifts positions, it directs the airflow between the five ports according to its configuration.

Directional Valve

3-position, 4-way, 4 ported Closed Center
The symbol represents a directional control valve with 3 positions, 4 paths, and 4 ports, featuring a closed center. In the center position, the valve is shut off and isolated from the other ports. When the valve shifts positions, it directs the airflow to and from the four ports depending on its current position.

5/2 Valve

2-position, 4-way, 5 ported
The symbol represents a directional control valve with two positions, four paths, and five ports.

Directional Valve

2-position, 4-way, 4 ported 
The symbol represents a directional control valve with two positions, four paths, and four ports.

Directional Valve

2-position, 3-way, 3 ported 
The symbol represents a directional control valve with two positions, three paths, and three ports.

2/2 Valve

2-position, 2-way, 2 ported
The symbol represents a basic directional control valve with two positions, two paths, and two ports.

3/2 Valve

The symbol represents a valve type with three ports and two positions. The valve can be used to open and close the airflow in a pneumatic circuit or to control the direction of the airflow.

Pneumatic symbols

What is a pneumatic symbol?

Pneumatic symbols are an effective way to describe the functionality and operation of often complex pneumatic systems. There is a set of symbols that represent pneumatic components and functions, including valves, cylinders, pressure sources, air filters, hoses, and much more. The symbols are used to create schematic representations of pneumatic systems, facilitating design, communication, and troubleshooting.
To maintain a common view of drawings with pneumatic components, standards are in place that establish standardized symbols used in pneumatic diagrams and drawings. The most widely recognized standard is ISO 1219-1. In addition, there is the "Japanese Industrial Standard (JIS)", but in most cases the symbols are identical to each other.
It is important for technicians and engineers working in the field of pneumatics to be familiar with the ISO 1219-1 standard and its symbols, as they are needed in the design and documentation of pneumatic systems. The standard helps ensure that all parties involved can understand and interpret pneumatic diagrams correctly.

Quicklinks: Symbols for pneumatic cylinders | Symbols for pneumatic valves | Line symbols| Common components in pneumatic systems | Symbols for direction valves

Symbols for Pneumatic Cylindres

Pneumatic sylindres convert air pressure to mechanical movement and are used to drive different types of appclications for moving and placing in pneumatic systems.

Single acting load returns

A single-acting pneumatic cylinder with load return can perform work such as moving a load when pressure is applied. After the pressure is released, the piston returns to its original position with the help of external force or a spring.

Single acting spring returns

Single-acting pneumatic cylinders with spring return are used in many industries. They perform movement in one direction and return to the original position with a built-in spring when pressure is released. The strength of the spring varies depending on the requirements.

Double acting non-cushioned

Double-acting pneumatic cylinders with spring return are used in many industries. They perform movement in two directions and return to the original position with a built-in spring when pressure is released. The strength of the spring varies depending on the requirements.

Double acting adjustable cushions

The symbol represents a type of pneumatic cylinder that is used to generate motion in two directions and is equipped with adjustable damping mechanisms. These cylinders allow for fine-tuned control over the speed of movement by regulating the flow of air in and out of the cylinder.

Single acting load returns

The symbol represents a type of pneumatic cylinder that is used to generate motion in two directions and is equipped with adjustable damping mechanisms. These cylinders allow for fine-tuned control over the speed of movement by regulating the flow of air in and out of the cylinder.

Cylinder Spring Return


The symbol­ re­presents a pneumatic cylinder that is used to generate linear motion and has a spring mechanism to return to its original position after pressure has been released. When compressed air is applied to one side of the piston, the piston moves outward, and when the pressure is released, it returns to its original position.

Cylinder Double Acting (Double Rod)

The symbol represents a pneumatic double-acting cylinder with double bars. The cylinder can generate linear motion in both directions. When compressed air is applied to one side of the piston, it moves outwards, and when the pressure changes and is applied to the other side, the piston moves in the opposite direction.

Cylinder Double Acting (Single Fixed Cushion)

The symbol represents a pneumatic cylinder that is double-acting and has a simple fixed damping that controls movement at the end points of the stroke. This type of cylinder is used when it is necessary to avoid collisions or excessive speed at the end of the movement.

Cylinder Double Acting (Two Adjustable Cushions)

The symbol represents a pneumatic cylinder that is double-acting and has two adjustable dampers to control movement at the end points of the stroke. These adjustable cushions allow you to adapt the movement to specific needs.

Symbols for Pneumatic Valves

Pneumatic valves are components that control the flow of air within pneumatic systems, and they can be used to regulate, stop, or direct the movement of air.

Safety Valve

The safety valve is a critical component of pneumatic and hydraulic systems. Its purpose is to protect the system from overload by regulating and relieving pressure at dangerous levels. It ensures that the system's pressure does not exceed its rated capacity, reducing the risk of damage and system failure.
Contrary to the relief valve, this component offers immediate pressure release, where as a relief valve is commonly used for continuous operation prohibiting excessive pressure buildup.

Flow Control

Flow control involves regulating and controlling the flow of gas or liquid in a system to achieve the desired speed, direction or amount.

Check Valve

Single-acting pneumatic cylinders with spring return are used in many industries. They perform movement in one direction and return to the original position with a built-in spring when pressure is released. The strength of the spring varies depending on the requirements.

Check Valve (Spring Loaded)

The symbol represents a pneumatic check valve equipped with a spring mechanism that keeps the valve closed until a sufficient pressure is reached. The purpose is to prevent air from flowing backwards into the system. When the pressure on one side of the valve becomes high enough to overcome the spring force, the valve opens and allows the flow to pass. When the pressure decreases, the valve automatically closes to prevent backward flow.

Line Symbols

 Line symbols are important in pneumatic diagrams and drawings to indicate direction, couplings and flow streams for air or pressure. 

 2 Lines joined

The symbol represents two connected pneumatic lines within a system, which can be connections or connections between components. The symbol indicates a physical coupling, which is important for transferring compressed air and controlling pneumatic functions.

3 lines joined

The symbol shows the connection of three pneumatic lines within a system. The symbol indicates where three overhead lines meet, often in pneumatic diagrams to illustrate how the airflow is distributed among different components. This helps to clarify the path of compressed air and its interaction with the parts of the system.

Lines Crossing

The symbol indicates that two or more pneumatic lines intersect within a system. It shows where the lines intersect and how the airflow is distributed between the parts of the system.

Double acting adjustable cushions

The symbol represents a type of pneumatic cylinder that is used to generate motion in two directions and is equipped with adjustable damping mechanisms. These cylinders allow for fine-tuned control over the speed of movement by regulating the flow of air in and out of the cylinder.

Main line

The symbol indicates the main line in a pneumatic system, distributing compressed air to the various components of the system.   The symbol shows where the main line is connected and how it is integrated in the system.  

Common symbols for Pneumatic Components

These frequently used symbols for pneumatic components or units are used in pneumatic flow sheets or diagrams, indicating how the various components are connected and operate in the system.

Accumulator

The symbol indicates a pneumatic component which stores compressed air. It equalizes variations in the pressure and provides extra air when needed.  

Air dryer

The symbol represents a pneumatic component used to remove moisture from the compressed air in a pneumatic system. Any moisture in the compressed air can cause problems like corrosion and reduced performance.  

Air motor 
(One direction flow)

An air motor is a pneumatic component which converts the energy of compressed air to mechanical movement. The symbol represents an air motor which only operates in one mechanical direction restricted by the flow. 

Air motor 
(Two direction flow)

The symbol represents a pneumatic air motor that can handle flow in two directions. Air motors with bidirectional flow are useful in applications where movement in both forward and backward directions is required, providing operators with greater flexibility in controlling mechanical systems.

Compressor

The symbol represents a pneumatic compressor used to compress and deliver air to a pneumatic system. A compressor takes in ambient air, compresses it, and delivers it at higher pressure to a pneumatic system. The increased air pressure is then used to power pneumatic actuators, valves, and other pneumatic components.

Differential pressure

The symbol is used to indicate when measurement or control of the differential pressure between two points within a pneumatic system is required.

Direction of Flow

The symbol is used to indicate the direction of air or fluid flow within a pneumatic system. It helps explain how different components and valves affect the flow direction and in which direction the air or fluid will move as it passes through the marked component.

Control- or Exhaustline

The symbol indicates a line or conduit connected to the outlet of a valve or control unit. It shows where the outgoing air flows from a component.

Filter

The symbol represents filters used to purify air or gas circulating within the system by removing particles and contaminants. This helps ensure that the air used in pneumatic systems is clean and free from debris that could damage components or affect system performance.

Filter (Automatic Drain)

The symbol represents a pneumatic filter component that not only purifies the air within the system by removing particles and contaminants but also features an automatic draining function. The automatic drainage is used to periodically remove accumulated condensate and other fluids from the filter.

Filter (Manual drainage) 

The symbol represents a pneumatic filter component that requires manual draining to remove accumulated condensate and other fluids from the filter regularly, in order to maintain the filter's efficiency.

Fixed restriction

The symbol represents a pneumatic component used to restrict airflow to a fixed level. This component is typically part of a pressure or flow regulation device and is used to control the speed or force of a pneumatic actuator. The symbol is usually accompanied by an arrow indicating the direction of airflow through the fixed restriction and a component that regulates the amount of airflow.

Lubrication

The symbol represents a pneumatic lubrication unit used to add lubricant, usually oil, to pneumatic systems. Lubricators reduce friction and wear on pneumatic components, helping to extend their lifespan and maintain proper function.

Lever

The symbol represents a lever used to manually activate or control a component within a pneumatic system. Levers are often used to manually operate valves, open or close airways, or adjust other parameters within pneumatic systems.

Lever operated 
(Spring Return)

The symbol represents a pneumatic valve or device that is controlled using a lever mechanism and features a spring return function. This type of valve is used to regulate airflow through the system.

External Pilot

The symbol represents a pneumatic valve or device that is controlled using an external pilot air stream. Pilot air is often used to control or activate functions such as valves and cylinders. This can be useful when you want to activate or deactivate a pneumatic component from a remote location using a pilot air signal.

Internal Pilot

The symbol represents a pneumatic valve or device that is controlled using an internal pilot air stream. Internal pilot provides independent control of pneumatic components without relying on external pilot signals or pressure sources.

Solenoid ​

The symbol represents a pneumatic or electric solenoid used to control a valve or another pneumatic component. A solenoid is a device that converts electrical energy into mechanical motion and is commonly used to open or close valves within pneumatic systems.

Detent

The symbol represents a mechanical device used to establish a fixed position in a pneumatic or mechanical component. It functions as a lock, providing clear positioning or preventing unintentional movement.

Spring

The symbol represents a spring in a pneumatic system. Springs are used to generate a return force and restore a component to its original position.

Mechanical

The symbol is used to indicate when mechanical components are present and have a specific function in the system.

Foot Operated

The symbol represents a mechanical component or device that is activated by a foot pedal.

Push Button

The symbol represents a push button used to activate or deactivate a component within a pneumatic system.

Manual

The symbol represents manual control or operation. It can be used for various manual handles, levers, knobs, or dials that are used to adjust or regulate pneumatic components or processes.

Directional Control Valves Symbols

Directional control valves can shift airflow between different directions and ports within a pneumatic system. The symbols show how the valve operates and how airflow can be controlled, including the number of ports and the various positions of the valve. These symbols are used to create diagrams and drawings that describe pneumatic systems and their functions.

5/3 Valve

3-position, 4-way, 5 ported Open Center
The symbol represents a directional control valve with 3 positions, 4 paths, and 5 ports, featuring an open center configuration and an exhaust center position. In an open center configuration, all ports are interconnected, allowing continuous airflow when the valve is in its center position. When the valve shifts positions, certain ports close while others open, altering the direction of airflow within the system.

5/3 Valve

3-position, 4-way, 5 Ported Pressure Center 
The symbol represents a directional control valve with 3 positions, 4 paths, and 5 ports, configured with a pressure center. In the pressure center position, the valve is neutral, with no connections to any port. When the valve shifts positions, it directs the airflow from one or more of the five ports.

5/3 Valve

3-position, 4-way, 5 Ported Closed Center
The symbol represents a directional control valve with three positions and five ports, where the center position is closed and isolated from the other ports. When the valve shifts positions, it directs the airflow between the five ports according to its configuration.

Directional Valve

3-position, 4-way, 4 ported Closed Center
The symbol represents a directional control valve with 3 positions, 4 paths, and 4 ports, featuring a closed center. In the center position, the valve is shut off and isolated from the other ports. When the valve shifts positions, it directs the airflow to and from the four ports depending on its current position.

5/2 Valve

2-position, 4-way, 5 ported
The symbol represents a directional control valve with two positions, four paths, and five ports.

Directional Valve

2-position, 4-way, 4 ported 
The symbol represents a directional control valve with two positions, four paths, and four ports.

Directional Valve

2-position, 3-way, 3 ported 
The symbol represents a directional control valve with two positions, three paths, and three ports.

2/2 Valve

2-position, 2-way, 2 ported
The symbol represents a basic directional control valve with two positions, two paths, and two ports.

3/2 Valve

The symbol represents a valve type with three ports and two positions. The valve can be used to open and close the airflow in a pneumatic circuit or to control the direction of the airflow.