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Pneumatic Components and Symbols

From DT Online

Collection of LEGO pneumatic components


Symbols

Pneumatic symbols are used to describe the function of the various valves and other devices which are connected together to form circuits and sub circuits.


Pneumatically controlled devices use pneumatic valves to control and direct the air and enable operations such as lifting, moving, pressing, etc.

PneumaticsValveSymbols.jpg


Symbols for valves are shown as boxes representing the different operating positions - the symbol shown for example is based on two boxes so it is a two position, or 2-stage, valve. Looking at any one of the boxes gives an indication of the number of ports on the valve - in this case there are 2 ports in each box (i.e. at centre top and bottom) so it would be a 2-port, 2-stage valve (2/2 Valve) - i.e. it has 2 ports and 2 operating states or positions that the valve can be in (i.e. Input and Output : Open or Closed).


In the left-hand box, the arrow indicates that both ports are open and air would be allowed to pass through the valve in this position. In the right-hand box, the same two ports are shown as blocked. In this position, air is not allowed to pass. Ports are where pipe can be connected and have numbers which, if they comply with standard ISO 5599, are stamped onto the casing of the valves as follows :


Port 1 :

Main Air

The Main Air input is supplied from a compressor or similar device and distributed through a manifold. Main air is identified by this symbol :
PneumaticsAirSupply.jpg
Port 2 :

Output Connection

Where connections are made to other components, usually cylinders. On five-port valves, used with Double-Acting Cylinders, it is usually connected to instroke and Port 4 is usually connected to outstroke is identified by this symbol:
PneumaticsOutletSymbol.jpg
Port 3 :

Exhaust

This port allows air trapped in the circuit to escape to atmosphere or exhaust. Also, cylinders need the air on the other side of the piston to escape. Five-port valves, for use with Double-Acting Cylinders, have a second Exhaust Port 5. Exhaust outlets are identified by this symbol :
PneumaticsExhaustAirSymbol.jpg
A 3/2 valve gets its name because it has three ports and two states as follows :
State 1 – off/unactuated state : The main air supply through the valve is blocked and so air is unable to reach other components, such as cylinders. However, any air within the cylinder is able to exhaust through the valve and this will allow the cylinder to return to its original position.
PneumaticsValvePortsClosed.jpg
State 2 – on/actuated state : The main air supply is able to flow freely through the valve and supply components, such as cylinders, with air. A three-port valve symbol shows both states side by side and is usually drawn in the off or unactuated state.
PneumaticsValvePortsOpen.jpg

Components

Air Supply and Distribution
Component Name and Description Symbol
PneumaticsCompressor.jpg
Compressor The symbol shown is that for the Main Air Supply which is normally supplied by a compressor. High pressure air can be produced using piston, screw or vane compressors.
PneumaticsAirSupply.jpg
AirReservoir.jpg
Receiver The air produced by the compressor is stored in a vessel called the receiver or reservoir. The function of the receiver is to store the air for future use, to smooth uneven pressure and to allow water to fall out of the air to the bottom of the tank where it can be drained.
PneumaticsReservoirSymbol.jpg
PneumaticsLineFilter.jpg
Filter Filters are used to remove small particles from the air which, if allowed to remain, would block small ports and jam spools etc.
PneumaticsLineFilterSymbol.jpg
PneumaticsRegulator.jpg
Regulator Compressors produce air at a higher pressure than is normally required to overcome losses in the distribution system. A pressure regulator is used to lower the pressure for the system components. A pilot signal (the dotted line on the right-hand side of the symbol) monitors the output pressure of the valve. This pilot pressure acts against a spring which is used to set the pressure.
PneumaticsRegulatorSymbol.jpg
PneumaticsManifold.jpg
Manifold This enables several components to be connected to the compressed air source and provides a means of switching circuits on and off.
PneumaticsManifoldSymbol.jpg
PneumaticsAirBleed.jpg
Air Bleed This is simply an open pipe that allows the air in the circuit to escape once pressure is reduced by a diaphragm valve.
PneumaticsAirBleedSymbol.jpg
PneumaticsAirLines.jpg
Air Pipes Connected The air produced by the compressor is distributed by air lines or pipe-work to the points where it is required. The lines or pipe can be connected together using 'T' pieces.
PneumaticsAirLinesConnectedSymbol.jpg
Air Pipes Not Connected In a factory the pipe-work is run downhill in a further attempt to remove excess water from the system.
PneumaticsAirLinesNotConnectedSymbol.jpg
DT Online Buyers' Guide
Stanley 8213360SCR001 240V 5 Litre Air Compressor 1/4 1/4 Air Hose Adaptor A4 1/8 Interstate Pneumatics VR440 1/4 Inch MPT x 1/4 Inch FPT In Line Air Regulator Bleed Valve by Interstate Pneumatics 5 Way 8 Ports Air Hose Pipe Manifold Block Splitter 1/8BSP Thread Blue 10 Pcs Straight Quick Connectors Pneumatic Fittings 4mm x 1/8 15M Clear Blue Polyurethane Fuel Gas Pneumatic Air PU Tube Hose 4x6mm
Stanley 240V 5 Litre Air Compressor 1/4"NPT Male to 1/8"Bsp Male Adaptor 1/4" BSP Female to 1/4" BSP Female Connector Air Hose Adaptor A4 1/8" Bsp Female--1/4''bsp Male Air Regulator Bleed Valve Manifold Block Splitter 1/8BSP Thread Blue Straight Quick Connectors 4mm x 1/8" PT Male (x10) 15M Clear Blue Polyurethane Pneumatic Hose 4x6mm
Control Valves
Component Name and Description Symbol
2PortValve.jpg
3-2 Valve This valve shows 3 ports in each box and 2 boxes to indicate it has 2 stages of operation - hence 3-2 Valve. Single-acting cylinders are normally controlled by three-port valves
Pneumatics3-2ValveSymbol.jpg
P-12-510.jpg
5-2 Valve This valve shows 5 ports in each box and 2 boxes to indicate it has 2 stages of operation - hence 5-2 Valve. Double-acting cylinders are normally controlled by a 5-port valve which is operated by Pilot Air signals from two three-port valves causing a spool inside the valve to move to one side or the other.
Pneumatics5-2ValveSymbol.jpg
  Exhaust The symbol shown is used to indicate when compressed air is released to the atmosphere - e.g. following the operation of a valve.
PneumaticsExhaustAirSymbol.jpg
FlowControlValve.jpg
Unidirectional Flow Control These control the speed of cylinder operation by restricting the flow of compressed air. This symbol shows the inclusion of a restrictor and a check valve, or non-return valve, used such that air is restricted from left to right and will free flow only from right to left.
PneumaticsUnidirectionalFlowControlSymbol.jpg
  2-way Flow Control This symbol omits the check valve to indicate that the air is able to flow in either direction
PneumaticsFlowControlValveAdjustable.jpg
  Fixed Value Flow Control This symbol omits both the check valve and the variable arrow to indicate that the air is able to flow in either direction with pressure lowered to a set value.
PneumaticsFlowControlValveFixed.jpg
DT Online Buyers' Guide
1/8BSP Thread 3Way 2Position Pushbutton Switch Air Mechanical Valve 2 Position 3 Way Selective Knob Pneumatic Mechanical Valve MSV-98322TB JM-07 1/4 PT Thread 2 Position 3 Way Roller Type Mechanical Pneumatic Valve Move&Moving(TM) 4H210-08 5 Way 2 Positions Pneumatic Mechanical Hand Lever Valve 
DC 12V 2 Position 5 Way G1/8 Move&Moving(TM) Aluminium Alloy One Way Quick Exhaust Air Shuttle Valve 1/4 Move&Moving(TM) Push in to Connect Inline Pneumatic Speed Flow Control Valve 4 mm OD
1/8BSP Thread 3Way 2Position Pushbutton Switch Air Mechanical Valve 2 Position 3 Way Selective Knob Pneumatic Mechanical Valve MSV-98322TB JM-07 1/4 PT Thread 2 Position 3 Way Roller Type Mechanical Pneumatic Valve 5 Way 2 Positions Pneumatic Mechanical Hand Lever Valve 12V 2 Position 5 Way Pneumatic Solenoid Valve One Way Quick Exhaust Air Shuttle Valve 1/4" PT 4mm Pneumatic Inline Flow Controller Valve
Pneumatic Logic
Component Name and Description Symbol
ShuttleValve.jpg
Shuttle Valve These are used with two valves in parallel and are also known as ‘OR’ valves. They allow a signal to pass through from either input A or B (or both) and will allow the reverse flow of system exhaust through these same inputs. A shuttle valve selects the higher of two pressures by means of a small ball inside which gets blown from side to side.
PneumaticsShuttleValveSymbol.jpg
PneumaticANDValve.jpg
AND Valve This valve can be used to logically decide if there is move than one signal present on the inputs. It can be used to determine if a part is in position ‘AND’ a guard is down before performing a clamping operation for example. The same logic ‘AND’ function can be achieved by combining two in series.
PneumaticsANDValveSymbol.jpg
DT Online Buyers' Guide
(Pneumatic Air Valves) Logic Air Valve - Line Mount OR (Pneumatic Air Valves) Logic Air Valve - Line Mount AND
Logic Air Valve - Line Mount OR Logic Air Valve - Line Mount AND
Actuators
Component Name and Description Symbol
PneumaticDiaphragmActivator.jpg
Diaphragm Actuator These are capable of detecting small changes in air pressure. The diaphragm is a stretched piece of rubber which expands and contracts with the changing air pressure of a Pilot Air signal from an Air Bleed, for example, and acts on the valve to change its state
PneumaticsDiaphragmActuatorSymbol.jpg
  Pilot Air Pilot signals can be used to operate a switch or actuator by monitoring the output pressure of a valve for example and supply a pressure which acts against a regulator spring to set the working pressure or to operate the spool inside a 5 port valve.
PneumaticsPilotAirSymbol.jpg
PneumaticsSolenoidActivator.jpg
Solenoid Actuator Solenoids uses an electrical pulse to change the state of the valve. This allows pneumatics to be combined with electrical or electronic systems involving computer or progammable logic control (PLC) if required.
PneumaticsSolenoidActivatorSymbol.jpg
PneumaticManualActivators.jpg
Control valves require switching in some way and there are many ways of actuating the them.

Solenoids and pilots are are switched indirectly from some other source : electrically in the case of a solenoid (by PLC for example) or by another valve in the case of a Pilot Air.

Solenoids and Pilot Air are common methods of operation but valve actuation can be achieved most simply by a mechanical operation.

Mechanical Actuators include push buttons, levers, rollers, and plungers. They are methods used for manual operation and shown illustrated are the actuator symbols.

Push Button
PneumaticsPushButtonActuator.jpg
Lever
PneumaticsLeverActuator.jpg
Roller
PneumaticsRollerActuator.jpg
Plunger
PneumaticsPlungerActuator.jpg
Pneumatic Cylinders (or Linear Actuators)
Component Name and Description Symbol
PneumaticsSingleActingCylinderDiagram.jpg
Single-acting Cylinder Pneumatic cylinders are more accurately termed linear actuators. In a single-acting cylinder, compressed air is used to push the piston out (outstroke), and a spring to return it (instroke). When compressed air is supplied to the cylinder, the piston rod extends. A single-acting cylinder is normally controlled by a three-port valve.
PneumaticsSingleActingCylinderSymbol.jpg
DoubleActingCylinder2.jpg
Double-acting Cylinder Double-acting cylinders use compressed air for the outstroke and also for the instroke by reversing the air flow direction which is achieved using a five-port valve. They can produce bigger forces and are used more than single-acting cylnders. They can be used for both pushing and pulling.
PneumaticsDoubleActingCylinderSymbol.jpg
DT Online Buyers' Guide
Double Action Single Rod Pneumatic Cylinder MAL 25 x 50 
-Baomain 32 mm x 100 mm SC32-100 Pneumatic Mini Cylinders 
Pneumatics Add-on Set for Lego 9686 Simple And Motorized Mechanisms Base Set Fischer Technik 533874 Fischertechnik Pneumatic 3 Building Kit
Double Action Single Rod Pneumatic Cylinder MAL 25 x 50 Baomain 32 mm x 100 mm SC32-100 Pneumatic Mini Cylinders Pneumatics Add-on Set for Lego 9686 Simple And Motorized Mechanisms Base Set Fischer Technik 533874 Fischertechnik Pneumatic 3 Building Kit