pneumatic1day

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Introduction to Pneumatics

The term “PNEUMA” is derived from the ancient Greek, and meant breadth or wind.

PNEUMATIC is the study of air movement and air phenomena.

Although the fundamentals of pneumatics rank amongst the earliest perceptions of mankind, it was not until the last century that the behavior and the fundamentals were researched systematically.

Some earlier applications and areas of use of pneumatics in the industry were; railways, mining and construction.

Real practical industrial applications of pneumatics dates back only to about 1950s.

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Properties of Air

78% Nitrogen

21% Oxygen

1% Other Gas (CO2, H, Ne, Krypton, Xenon,

Water, etc.)

• Air is compressible.• Air is expandable.• Air when compressed produces a maximum

temperature of 200 to 300°C.• Air contains 40PPM of solid particles and

increases to 9 times when compressed.

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Advantages of compressed air

AMOUNT Air is available practically everywhere for

compression, in unlimited quantities.

TEMPERATURE Compressed Air is insensitive to temperature

fluctuations. This ensures reliable operation, even

under extreme conditions of temperature.

TRANSPORT Air can be easily transported in pipelines, even

larger distances. It is not necessary to return the

compressed air.

STORABLE A compressor need not be in continuous operation.

Compressed Air can be stored in and removed from

a reservoir. In addition, transportation in the

reservoir is possible.

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Advantages of compressed air(continued)

EXPLOSION PROOF Compressed Air offers no risk of explosion or fire,

hence no expensive protection against explosion

is required.

CLEANLINESS Compressed Air is clean since any air which

escapes through leaking pipes or elements does

not cause contamination. This cleanness is

necessary, for example, in the food, wood, textile

and leather industries.

CONSTRUCTION The operating components are of simple

construction, and are therefore inexpensive.

SPEED Compressed Air is very fast working medium.

This enables high working speeds to be attained.

(Pneumatic cylinders have a working speed of 1 to

2 Meters/Second).

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Advantages of compressed air(continued)

ADJUSTABLE With compressed air components, speeds and

forces are infinitely variable.

OVERLOAD SAFE Pneumatic tools and operating components can

be loaded to the point of stopping and they are

therefore overload safe.

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Disadvantages of compressed air

PREPARATION The Compressed Air needs good preparations.

Dirt and humidity may not be present. (Wear of

Pneumatic Components).

COMPRESSIBLE It is not possible to achieve uniform and constant

piston speeds with compressed air.

FORCE REQUIREMENT Compressed Air is economical only up to a

certain force requirement. Under the normally prevailing working

pressure of 700 KPa (7 Bar / 101.5 PSI) and dependent on the travel

and speed. The limit is between 20,000 and 30,000 N

(2,000 and 3,000 Kg.f).

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Disadvantages of compressed air(continued)

EXHAUST AIR The exhaust air is loud. This problem has now,

however, been largely solved due to the

development of sound absorption material.

COSTS Compressed Air is a relatively expensive means

of conveying power. The high-energy costs are

partially compensated by inexpensive

components and higher performance. (Number of cycles).

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Summary of Energy Supply

Compressor Compressor

Plant Plant

Service Unit Service Unit

Piping System Piping System

Dryer Dryer

Receiver Receiver

• Types of Compressor (Positive displacement, Flow Compressor)

• Flow Rate• Pressure• Service



• To dampen pressure fluctuation

• Condensation of water vapor• Safety



• Cooling (note: Dew Point)• Absorption• Adsorption


• Ring Circuit• Gradient 1-2%• Tapping Outlets pointing upwards• Diameter

• Ring Circuit• Gradient 1-2%• Tapping Outlets pointing upwards• Diameter

• Filter• Pressure Regulator• Lubricator


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Plant Plant



Dryer Dryer

Receiver Receiver





Compressors are required to compressed

the gas to the desired working pressure

for transmission of power.

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Plant Plant



Dryer Dryer

Receiver Receiver • To dampen pressure

fluctuation• Condensation of water vapor• Safety



Compressed Air Receiver serves to

stabilized the air supply and smoothens

pressure fluctuations in the network when

air is consumed.

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Plant Plant



Dryer Dryer

Receiver Receiver



Good preparation is important when using

compressed air. Water (moisture) is introduced

in the system by the compressor which should be

dealt with at the point of usage.

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Air outlet

Air inlet

Refrigerating unit Air to air-heat exchanger

Moisture separator

Refrigerant

Moisture separator

Refrigeration machine

Air Drying

Refrigeration Drying

If the temperature is

lowered further, the

water vapor contained

in it begins to

condense.

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Dew Point Curve

Example:

At a dew point of

40°C (313°K), the

quantity of water in

1M³ air is 50 Grams.

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Absorption Drying

Desiccant

Condensate

Moist air inlet

Condensate drain

Dry air outlet

Air Drying (continued…)

Moisture, gases or dissolved

materials from the air combines

with the desiccant to form into a

solid or liquid state. It is a

chemical process and no

external energy is required.

Simple installation but high

operating cost because the

desiccant have to be discarded.

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Shut-off valve (open)

Prefilter (oil filter)

Adsorber 1

Hot airHeater

Shut-off valve (open)

Dry air

Shut-off valve (closed)

Shut-off valve (closed)

Adsorber 2

Secondary filter

Blower

Adsorption Drying

Air Drying (continued…)

Moisture, gases or

dissolved materials from

the air deposits on the

porous surface of the

desiccant. It is a

physical process and

regeneration is possible

through hot air flow.

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Plant Plant



Dryer Dryer

Receiver Receiver

• Gradient 1-2%• Tapping Outlets pointing upwards• Diameter• Ring Circuit

• Gradient 1-2%• Tapping Outlets pointing upwards• Diameter• Ring Circuit

Condensation in the system should be

prevented. Condensate can be trapped in

pipelines at lowest points. Pipelines should

be installed with downward gradient,

measured in the direction of flow.

Piping diameter should be selected primarily

on the basis of flow volume, pipe length and

working pressure.

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Installation of Pipelines

Branch Line

Inter-connected System

Ring Circuit

Ring circuit are the commonly

used pipeline installation. Gas

can flow from two direction and a

uniform supply can be obtain

where there is heavy

consumption.

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Plant Plant



Dryer Dryer

Receiver Receiver



Compressed air needs good preparation.

Dirt and humidity should be prevented as

it may wear pneumatic components or

cause it to malfunction.

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Service Units

Compressed Air Filter

Combined Symbols - Air Service Units

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Inlet

Outlet

Water Trap

Drain

Filter Element

Baffles

Filter with Water Trap Manual Control Filters remove contaminants,

mainly condensed water from

compressed air. Compressed air is conducted into

the filter bowl and is rotated at high

speed. Heavy particles of dirt and water particles are centrifuged onto the

wall of the filter bowl and they remain

there. Condensed water accumulates in

the lower part of the filter bowl and is drained through the drain plug

when the water reaches the maximum

level mark. Fine particles are retained

by the filter element through which

the air has to flow.

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Service Units

Pressure Regulating Valve with Relief Port

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Valve Body

Inlet Outlet

Vent

Spring and

Adjusting screw

Pressure operation

Pressure Regulator with Relief Port

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6 Bar

The set screw permits adjustment of the initial

tension in the diaphragm spring. The diaphragm lifts off the push rod off its seat.

The push rod shuts off the exhaust port in the

diaphragm.

Operation of Pressure Regulator with Relief Port

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6 Bar

4.5 Bar

If the pressure in the volume with the output

port exceeds the set value, the diaphragm moves

down first, shutting off the input port and then

opening the exhaust ports to relieve the excess

pressure.

Operation of Pressure Regulator with Relief Port

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Compressed Air Lubricator

Service Units

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Lubricator

Air flows through the lubricator from left to right. Some of the air flowing through the valve is guided through a nozzle.

Due to the resulting pressure drop, oil is drawn from an oil reservoir through a feed pipe.

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Lubricator

The air lubricator is used when

-Extremely rapid oscillating motions are required

-With cylinders with large diameters(125mm)

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The Structure of Pneumatic Systems

Energy supplyEnergy supply

Signal inputSignal input

Signal processingSignal processing

Command Execution

Signal Output

Processing elements: Directional control valves, Shuttle valves, Dual-pressure valves, Sequencers, Pressure sequence valves

Processing elements: Directional control valves, Shuttle valves, Dual-pressure valves, Sequencers, Pressure sequence valves

Input elements: Push-button directional control valves Roller lever valves, Proximity switches, Air barriers

Input elements: Push-button directional control valves Roller lever valves, Proximity switches, Air barriers

Working elements: Cylinders Motors Optical indicators

Working elements: Cylinders Motors Optical indicators

Control elements: Directional control valvesControl elements: Directional control valves

Energy supply elements: Compressor Pneumatic reservoir Pressure regulating valve, Service units

Energy supply elements: Compressor Pneumatic reservoir Pressure regulating valve, Service units

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Energy supply elements

1A 1S3

1V2 4 2

1V1 2

14 12

1 1(3)

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3

1S1 2 1S2 2 1S3 2

1 3 1 3 1 3

0Z0S 2

1 3

Input elements

Processing element

Control element

Working element

System Circuit Diagram

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Symbols for the Power Supply Section

Energy Supply: Compressor with constantdisplacement volume

Pneumatic reservoir PressureSource

Maintenance:

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1 3

Filter Water separator with

manual actuation Water separator with

automatic condensate drain

Pressure regulating valvewith relief port, adjustable

Lubricator

Combined Symbols: Air Service Unit (consisting of: Compressed air filter, Pressure regulating valve, Pressure gauge and compressed air lubricator)

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Non-return,

Flow Control

and Pressure

Control Valves

Symbols for Control Elements

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Symbols for the Principle Working Elements

LinearActuators:

Double-acting cylinder with single, non-adjustable cushioning

Single-acting cylinder Double-acting cylinder Double-acting cylinderwith through piston rod

Double-acting cylinder withadjustable cushioning at both ends

Rodless cylinder withmagnetic coupling

Rotary Drives:

Air motor, constant displacement,rotation in one direction

Air motor, variable displacement,rotation in one direction

Air motor, variable displacement,rotation in both directions

Pneumatic rotary motor

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Poppet Valves

Ball Seat Valve

Disc Seat Valve

Slide Valves

Longitudinal Slide Valve

Longitudinal Flat Slide Valve

Plate Slide Valve (Butterfly Valve)

Design Characteristics of Directional Valves

Valve designs are categorized as follows:

The design principle is a contributory factor with regards to

service life, actuating force, means of actuation, means of

connection, and size.

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3/2-Way Valve: Ball Bearing Seat, Normally Closed Position

Ball Seat Poppet Valve

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3/2-Way Valve: with Disk Seat, Normally Closed Position

Disk Seat Poppet Valve

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5/2-Way Double Pilot Valve, Pneumatically Actuated, Both Sides

5 Working ports, 2 switching positions

The valve has a memory function. A short signal (pulse) is sufficient for actuation.

Longitudinal Slide Valve

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4/3-Way Valve, Mid-Position Closed, (flat slide valve)

4 Working ports, 3 switching positions

Flat slide valves are mostly actuated manually as other types of actuation can only be implemented with difficulty.

By rotating two disks, the flow channels are connected with, or isolated from each other.

Longitudinal Flat Slide Valve

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SWITCHING SYMBOLS FOR VALVES

The connecting lines for supply and exhaust air are drawn outside the square.

The valve switching position is shown by a square.

The number of squares corresponds to the number of switching positions.

Lines indicate the flow paths, arrows indicate the direction of flow.

Closed ports are shown by two lines drawn at right angles to one another.

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Directional Control Valves:Ports and Switching Positions

2/2-way valve, normally open position

Number of ports

Number of switching positions

3/2-way valve, normally closed position

3/2-way valve, normally open position

4/2-way valve, flow from 1 to 2 and from 4 to 3

5/2-way valve, flow from 1 to 2 and from 4 to 5

5/3-way valve, mid-position closed

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Connection Coding As per ISO 1219As per ISO

5599

Working or Outlet ports

A, B, C… 2, 4, 6…

Power Connection P 1

Drain, Exhaust Ports R, S, T… 3, 5, 7...

Leakage Line L 9

Control Lines X, Y, Z… 12, 14, 16…

Valve Connections Labeling

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PORT DESIGNATIONS

Port designation in accordance with DIN ISO 5599-3 "Fluid Technology – Pneumatics, 5-Way Valves"

1 -Supply port2, 4 -Working ports3, 5 -Exhaust ports

10 -Signal applied blocks flow from 1 to 212 -Signal applied opens flow from 1 to 214 -Signal applied opens flow from 1 to 481, 91 -Auxiliary pilot air

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End of Presentation

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