PNEUMATIC CONTROL

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COMPONENT,SYMBOL AND FUNCTION

INTRODUCTION

PNEUMATIC CONTROLMAIN PAGE

AIR SUPPLY

SIMPLE PNEUMATIC CONTROL CIRCUIT

Learning OutcomeLearning Outcome

List pneumatic components and sketch their List pneumatic components and sketch their symbols.symbols.

State the functions of pneumatic components.State the functions of pneumatic components.

Describe pneumatic components operation.Describe pneumatic components operation.

Sketch and describe simple pneumatic control Sketch and describe simple pneumatic control circuit.circuit.

Develop simple pneumatic control circuit and explain Develop simple pneumatic control circuit and explain its operation principle.its operation principle.

Students should be able to:

INTRODUCTIONINTRODUCTION

INTRODUCTIONINTRODUCTIONIn pneumatic system, the medium used to transfer In pneumatic system, the medium used to transfer energy is energy is COMPRESSED AIR.COMPRESSED AIR.

Generally, the pneumatic and hydraulic system are Generally, the pneumatic and hydraulic system are similar.similar.

The pneumatic system normally applied to light The pneumatic system normally applied to light and medium jobsand medium jobs

The pneumatic system is simpler, easier, cheaper The pneumatic system is simpler, easier, cheaper and safer than hydraulic system.and safer than hydraulic system.

Examples of Pneumatic application AIR SUPPLY

The air supply for pneumatic system needs to be compressed and filtered from contaminants such as water and humidity.

Clean air needs to be fabricated to reduce friction, wear and equipment erosion and also smoothen the movement.Compressed air supplied by compressor.

COMPONENT, SYMBOL & FUNCTION

4 main sections that required to operate pneumatic system

a. Supply service sectionc. Actuator or transducer

section

b. Pneumatic control sectiond. Energy transfer / transmitter

section

PNEUMATIC SYSTEM BLOCK DIAGRAM

Pneumatic system block diagram

Example of pneumatic system

SUPPLY SERVICE SECTION

Component Function Photograph Symbol

Electrical Motor• To run the pump.

• The motor continues to rotate until the air storage full.

Compressor•Pump in and increase the air,

gas, vapour pressure higher than the original pressure.

Cooler•Cool the compressed air by

filling the air in a condenser.

Service unit•Consist of filter, regulator and

lubricator.

Tank

(Air receiver)

Stored the compressed air and is installed next to compressor.

•The function of this section is to compress the air from the atmosphere.

•The air is compress by a compressor and stored in a tank.

SUPPLY SERVICE SECTION

Component Function Photograph Symbol

Dryer • Dry out the air moisture

Air filter•Filter the air entering the

system from any contamination.

Lubricator

• To increase the air flow efficiency.

• Reduce friction and wear of the components.

Pressure gauge•Show the air pressure reading

of the system.

Pressure regulator

• Control the pressure so there will be no excess pressure throughout the system.

PNEUMATIC CONTROL SECTION

Component Function Photograph Symbol

Pressure control valve

To control the pressure of compressed air at certain section below the component’s pressure limit.

Flow control valve

•Fix limit

•Adjustable limit

•Fix limit controls the air flow to the actuator or the actuator speed.

•Adjustable limit act as a regulator.

Directional control valve

Control the required direction flow. Can be done by:

•Hand / foot

•Rope / chain

•Lever / gear

•Solenoid energy

•Plunger and pneumatic energy

The type of valve is determined according to:

•Number of flow direction

•Number of position

•The way it is operated

•The function of this unit is to explain pressure control, flow rate and direction of compressed air.

FLUID CONTROL SECTION

Component Function Photograph Symbol

•2/2 valve (2 ports, 2 position)

•Has 1 direction output control.

•2 types:

–Normally open

–Normally closed

•3/2 valve (3 ports, 2 position)

•Has 2 directions output control.

•2 types:

–3/2 open

–3/2 closed

Flow control valve

•4/3 valve (4 ports, 3 position)

•Has 4 directions output control in three position.

•2 types:

–Normally open

–Normally closed

ACTUATOR OR TRANDUCER SECTION

Component(Linear actuators)

Function Photograph Symbol

Single acting cylinder

• To move load in 2 linear directions.

• The cylinder has a rod, a hole an spring to move the piston back to its original position after use.

Double acting cylinder

• To move load in 2 linear directions.

• The cylinder has a rod and two holes without spring.

Double acting cylinder with double ended rod

•To move load in 4 linear directions (1 cylinder 4 direction).

•The cylinder act as double acting cylinder but it can do a job in 2 different direction.

(Semi-rotating actuators)

•Motor

• The hydraulic motor is required if the desired work needs a circular motion.

• Several types of motors that could rotates at 90o and 180o.

•Actuator and tranducer is a device that converts HYDRAULIC energy to MECHANICAL energy.

ENERGY TRANSFER SECTION

SYMBOL Function

Compressor

• Compressed air from the atmosphere.

Pneumatic motor

• Convert the compressed air into mechanical power.

SYMBOL Function

Filter

• Separate contaminants from entering the pneumatic system.

Pressure relief valve

• Prevent the hydraulic system from overloading and limit the torque of hydraulic motor cylinder.

•This section transfer the compressed air from supply section anddistributed into the circuit through hoses and tubes.

TRANSMITTER / ENERGY TRANSFER SECTION

SYMBOL Function

Cooler

• Cool the compressed air

Lubricator• Lubricate the air flow.

• Reduce friction and wear out of components.

Pressure gauge• Measure pressure flow at

the fluid line.

• Usually installed after the filter.

Carrier main pipe / connector source

• Transfer the fluid throughout the system.

SYMBOL Function

Pilot control line

Flexible line• Transfer the fluid to the

pilot to move the valve.

Flow controller

(throttle valve)•Limit the volume of

compressed air that flows to the specific flow pipe.

Flow controller

(throttle valve -adjustable) •Adjust the air that flows

to specific places.

TRANSMITTER / ENERGY TRANSFER SECTION

SYMBOL Function

Double pressure valve • Allow two directional

flows either from the left or right direction.

Pressure reducing valve • Reduce the pressure at

certain parts in the pneumatic circuit.

Shut off valve• Stop the hydraulic

system for assembly and repairs.

Pressure switch•Control the pressure at a

specific location by disconnecting the electrical source at the pump meter.

SYMBOL Function

Exhaust pipe

• Flow out compressed air to control the pressure.

Joint source / manifold •Pipe joint.

Shuttle valve•Able to make selection

within two inputs.

Quick exhaust valve •To release compressed air more efficiently

TRANSMITTER / ENERGY TRANSFER SECTION

SYMBOL Function

Check valve

• Block the flow from the opposite direction.

Pressure valve• Consist of pressure

regulator, lubricator, dryer, cooler and filter.

3 ports, 2 position valve (3/2 way valve)

•Control flow direction by using three holes and two position valves.

Pressure control valve

• Control the compressed air to ensure that pressure does not exceed overpressure in circuit.

SYMBOL Function2 ports, 2 position valve (2/2 way valve) • Control flow direction

by using two holes and two position valves.

Single acting cylinder • Convert pneumatic power into mechanical power.

• One direction spring return.

• Linear motion.Differential cylinder with double ended rod

• Convert pneumatic power into mechanical power.

• Pneumatic control in two direction A and B.

• Linear motion.

TRANSMITTER / ENERGY TRANSFER SECTION SYMBOL Function

Double acting cylinder• Convert pneumatic

power into mechanical power.

• Pneumatic control in two direction A and B.

• Linear motion.

Telescopic cylinder• Convert pneumatic

power into mechanical power.

• Rod’s displacement is twice the normal displacement

Single acting piston• Convert pneumatic

power into mechanical power.

• Load return the piston back to its position

SYMBOL Function3 ports, 2 position valve normally closed (3/2 way valve)

• Control flow direction by using three holes and two position valves.

2 ports, 2 position valve (4/2 way valve)

• Control flow direction by using four holes and two position valves.

Pneumatic one directional flow motor • Convert pneumatic

power into mechanical power

• Rotates at 180o.

Pneumatic two directional flow motor

• Convert pneumatic power into mechanical power

• Rotates into 2 different direction.

TRANSMITTER / ENERGY TRANSFER SECTION

SYMBOL Function

Swivel pneumatic motor

• Convert pneumatic power into mechanical power.

• Rotates in semi-rotary actuator.

Double acting cylinder

• Convert pneumatic power into mechanical power.

• Pneumatic control in two direction A and B.

• Linear motion only.

SYMBOL Function

MANUAL OPERATIONLever

• Lever is used to ease the valve operation.

Pedal

• For foot pump only.

Push button• Control by pushing the

button.

Knob• Knob is turned to

enable the valve to operate.

TRANSMITTER / ENERGY TRANSFER SECTION

SYMBOL Function

Pneumatic drive• Pneumatic is triggered to

control the valve.

Pilot signal

• Pneumatic is triggered to control the valve.

Driver•Released pneumatic is

triggered to control the valve.

SYMBOL Function

ELECTRICAL

Solenoid • Coil will become magnetic and control the valve.

Motor • The motor rotates the valve

SYMBOL Function

MECHANICAL

Cam

•Rotating wheel-like.

Spring• Spring will return the

valve to its original position.

Plunger

• A pin-like device that can be pressed

EXAMPLE OF PNEUMATIC CIRCUIT

BEFORE OPERATION AFTER OPERATION

THE END