PNEUMATIC SYSTEM

PNEUMATIC SYSTEMPNEUMATIC AND HYDRAULIC ( JJ512)

Can you think for a whileWHAT IS PNEUMATIC??A fluid power is one that transmits & control energy through the use of pressurized liquid or gas4PNEUMATIC IS A SYSTEM DRIVEN BY FLUID POWERDEFINITIONPneumatics is the use of gas to transmit power from one point to another.

Derived from the Greek word ---Pneu = WindMatic = Power

:- therefore,the pneumatic systemmay beinterpretedas asystemdrivenbywind power.ADVANTAGES AND DISTINGUISHING CHARACTERISTICS OF COMPRESSED AIRAVAIBILITYIs available practically everywhere in unlimited quantitiesTRANSPORTCan be easily transported in pipelines, even over large distancesSTORAGECan be stored in a reservoir and removed as required.TEMPERATUREIs relatively insensitive to temperature fluctuations. This ensure reliable operation, even under extreme conditions.EXPLOSION PROOFNo risk of explosion or fireCLEANLINESSUnlubricated exhaust air is clean. Any unlubricated air which escape through leaking pipes or components does not cause contamination.COMPONENTSThe operating components are of simple construction and therefore relatively inexpensiveSPEEDIs a very fast working medium. This enables high working speeds to be attained.OVERLOAD SAFEPneumatic tools and operating components can be loaded to the point of stopping and are therefore overload safe.ADVANTAGES OF PNEUMATIC SYSTEMAir is easily available everywhereThe return can be ignoredCompressed air is able to flow quickly through the pipes and valvesCompressed air can be stored in jar/tankNo Pollution occurs due to leakageLines are easy to installCompressed air offers no risk of explosion or fire

DISADVANTAGES OF PNEUMATIC SYSTEMThe air must be treatedLeakage is disadvantageous of the constant power lossAt pressures above 6 bar, technical security control is needed.More force is required to move the larger diameter cylinderINDUSTRIAL APPLICATIONS EMPLOYING PNEUMATICS Automobile Industry Food Processing Industry Shipping Industry ElectronicsIndustry RoboticsIndustry

USAGES OF COMPRESSED AIR IN DAILY LIFEExpand transportation tyreWrapping food processSpray paintOpen and Close Door busPNEUMATIC APPLICATIONIN DAILY LIFE IN INDUSTRIALIN CARRYING AND WORKING OPERATIONAir GunClampingDrillingInsect SprayShiftingTurningJack Air PositioningMillingDoor BusPackagingSawingSpray PaintSorting of PartsFinishingGrinderStacking of ComponentFormingPNEUMATIC COMPONENT

COMPONENTDESCRIPTIONCompressorTo gather and compress air from normal to high pressure. Those air compressors in which successive volumes of air are enclosed and then elevated to a higher pressure by reducing the volume of the enclosure holding air.Air dryerTo dry the compressed air before it is provided to pneumatic system and to avoid pneumatic components form corrosion.ReceiverTo receive and keep compressed air. Receiver should be fitted with a safety valve, pressure gauge to manage the air pressure.Service UnitConsist of tree components. There are filter, regulator and lubricator. Its functions is to remove all contaminants such as dust and rust particles from the compressed air, manage air pressure and to extend Control ValveDetermines the flow of air between its ports by opening, closing or changing its internal connections. So directional control valve is used to control air and cylinder direction or movement.ActuatorTo transform the potential energy of the compressed air into mechanical work. The work done by pneumatic actuator or rotary.

PNEUMATIC CONTROL SYSTEMThank you

AIR GENERATION AND DISTRIBUTIONPNEUMATIC AND HYDRAULIC(JJ512)

RELATED THEORYPRESSURE3 ways to measure pressure which is in kPa, Bar and Psi unit.1 atm (atmosfera) = 100 kPa= 14.5 psi= 1.0132 bar= 100 kN/m2Boyles LawWhat is Boyles Law?

Boyles Law is one of the laws in physics that concern the behaviour of gasesWhen a gas is under pressure it takes up less space:The higher the pressure, the smaller the volumeBoyles Law tells us about the relationship between the volume of a gas and its pressure at a constant temperatureThe law states that pressure is inversely proportional to the volumepressurevolumeBoyles Law

P= 1 , V= 1P= 2 , V= 1/2P= 5 , V= 1/5 P1V1 = P2V2 P1 = 1/V1

19ForceIn Newton unit

forces exerted by the actuator cylinder is not 100% because of losses due to friction that occurs at the surface of the piston and the cylinder surface actuators. So the effective force will be :

F [N] = P [N/m2] x A [m2]Feff [N] = P x D X 7Dew PointDew Point is the temperature at which water vapor in the air begins to condense to form liquid water.Can cause problems in a pneumatic system when the temperature of the compressed air drops to the dew point and the vapor condenses into liquid water

AIR COMPRESSORIs basically an air pump that compresses air into the receiver tank. Compress air from atmospheric pressure to a higher pressureThis is done by reducing the air volumeThe receiver tank acts as a pressure source from which the system can draw as dictated by the flow demand. TYPES OF COMPRESSORPOSITIVE DISPLACEMENTa given quantity of air or gas is trapped in a compression chamber and the volume which it occupies is mechanically reduced, causing a corresponding rise in pressure prior to discharge

At constant speed, the air flow remains essentially constant with variations in discharge pressure

A type of compressor that delivers a fixed volume of air at high pressureNon positive displacementAlso called dynamic compressor Dynamic compressors impart velocity energy to continuously flowing air or gas by means of impellers rotating at very high speeds.The velocity energy is changed into pressure energy both by the impellers and the discharge volutes or diffusersA type of compressor that delivers larger volumes of air at lower pressure.

Impeller

-POSITIVE DISPLACEMENT-RECIPROCATING COMPRESSOR(PEMAMPAT JENIS SALINGAN)Air taken in at atmospheric pressure is compressed to the required pressure in a single stroke.Downward movement of the piston increases volume to create a lower pressure than that of the atmosphere, causing air to enter the cylinder through the inlet valve.At the end of the stroke, the piston moves upwards, the inlet valve closes as air is compressed, forcing the outlet valve to open discharging air into a receiver tank..a. Single Stage Piston Compressor

Suction line Suction valveDischarge lineValve plateHeadDischarge valvePiston Rings CrankshaftConnecting RodA. SINGLE STAGE PISTON COMPRESSOR B. TWO STAGE PISTON COMPRESSOR When air is compressed above 6 bar, the excessive heat create greatly reduces the efficiency. Because of this, piston compressors used in industrial compressed air systems are usually two stageAir is taken in at atmospheric pressure is compressed in two stages to the final pressureIf the final pressure is 7 bar, the first stage normally compresses the air to approximately 3 bar, after which it is cooled. It is then fed into the second stage cylinder which compresses it to 7 bar.The compressed air enters the second stage cylinder at a greatly reduced temperature after passing through the intercooler, thus improving efficiency compared to that of a single stage unit.

b. Two Stage Piston Compressor DIAPHRAGM COMPRESSORDiaphragm compressor provide compressed air in the 3-5 bar range totally free of oil and are therefore widely used by food, pharmaceutical and similar industries.The diaphragm provides a change in chamber volume. This allows air intake in the down stroke and compression in the up stroke.

Diaphragm compressorROTARY COMPRESSORSROTARY SLIDING VANE COMPRESSOR

SCREW COMPRESSOR.

ROTARY SLIDING VANE COMPRESSOR

Volume increaseOutlet portVanerotor

Inlet portThis has an eccentricity mounted rotor having a series of vanes sliding in radial slots.As the rotor rotates, centrifugal force holds the vanes in contact with the stator wall and the space between the adjacent blades decreases from the air inlet to outlet, so compressing the airLubrication and sealing is achieved by injecting oil into the air stream near the inlet.The oil also acts as a coolant limit the delivery temperature.

Screw compressor

Volume increaseINLETOUTLET

Two meshing helical rotors rotate in opposite directions.The free space between them decrease axially in volume and this compresses the air trapped between the rotors.Oil flooding provides lubrication and sealing between the two rotating screws.Oil separators remove this oil from the outlet air.

The basic operating theory of dynamic compressors is converting the kinetic energy of high-speed air into pressureDynamic compressor designs are either:CentrifugalAxial

NON-POSITIVE/ DYNAMIC DISPLACEMENT39Centrifugal dynamic compressor

Centrifugal dynamic compressor:An impeller increases airspeedPrime mover energy is converted into kinetic energy as airspeed rapidly increases through the impellerKinetic energy is converted to air pressure as air movement slows in the volute collector40Impeller assembly of a centrifugal dynamic compressor

41Axial-flow dynamic compressor:Rotating rotor blades increase air speedFixed stator blades decrease airspeedKinetic energy is converted to air pressureSeries of rotor and stator sections are staged to form the axial-flow compressor42Compressor Design and OperationAxial-flow dynamic compressor

43Compressor Design and OperationPressure is created when high-speed air is slowed by the fixed stator blades

NON-POSITIVE/ DYNAMIC DISPLACEMENT1. CENTRIFUGAL COMPRESSORD : A type of dynamic compressor that compresses air and expels it with a centrifugal force from a rotating wheel with radial vanes. Centrifugal compressors are often used for fans and cooling units. 2.AXIAL COMPRESSORD: The air is accelerated in the axial direction of flow by means of blades.

CONCLUSION

+ ve displacement compressor are used in fluid power application because they are capable of producing flow against high pressures.

- ve displacement compressor are low pressure, high flow pumps that are used in fluid transfer47FAD is the actual quantity of compressed air at the discharge of the compressorFAD at atmosphere pressure is vary depending on placeThe standard air for free air pressure standards is

1.010 BAR = 0OC

FREE AIR DELIVERY (FAD)AIR COMPRESSOR ACCESSORIES Consist of Filter, Regulator and Lubricator. Function to regulate the pressure and lubricate the air.RIPSRESERVOIR UDARAINPUT STRAINERPRESSURE RELIEF VALVESERVIS UNITFor the continuing performance of control systems and working elementit is necessary to guarantee that the air supply is: at the required pressure, dry and clean.4950AIR DEHYDRATIONLoweringthe temperature anddrying airafterthe compression processT&Dry air50AFTER/ CONTINUOUS COOLERSAfter final compression, the air will be hot and, when cooling, will deposit water in considerable quantities in the air-line system which should be avoided.The most effective way to remove the major part of this condensate is to subject the air to after-cooling, immediately after compression.Aftercoolers are heat exchangers, being either air cooled or water cooledAIR COOLEDConsisting of a nest of tubes through which the compressed air flows and over which a forced draught of cold air is passed by means of a fan assembly. The outlet temperature of the cooled compressed air should be approximately 15 c above the ambient cooling temperature

Essentially, a steel shell housing tubes with water circulating on one side and air on the other, usually arranged so that the flow is in opposite direction through the cooler.A water cooled aftercooler should ensure that the air discharged will be approximately 10 c above the temperature of the cooling waterAn automatic Drain attached to, or integral with, the aftercooler, removes the accumulated condensation.

WATER COOLED

AIR DRYERS56ABSORPTION DRYINGPENGERING UDARA

The compressed air is forced through a drying agent (lithium chloride or calcium chloride) which reacts with the moisture to form a solution which is drained from the bottom of the vessel shown in figure.

The drying agent must be replenish at regular intervals as the dew point increase.

Advantages: low initial and operating cost 57ADSORPTION DRYING

Activated aluminaSilica gelWater is deposited on the surface of solids.

Chemical such as silica gel or activated alumina in granular form is contained in a vertical chamber to physically absorb moisture from the compressed air.

Usually two tanks are used. When the gel in one tank is saturated, the air flow is switched to the dry, second tank and the first tank is regeneratedby hot-air drying.

The lowest equivalent dew points (down to 90 C) can be achieved by means of adsorption drying58COOLANT / REFRIGERANT /LOW TEMPERATURE DRYING

The aim is to reduce the temperature of the air to a dew point which ensures that the water in the air condenses and drops out in the quantity required.

The air entering into the refrigerant dryer is pre-cooled in a heat exchanger by escaping cold air.

It is then cooled in the cooling unit to temperatures between +2c and 5 c.

The dried compressed air is filtered.

Before the compressed air is output into the network, the air is heated back to ambient conditions.

59MAIN LINE FILTER

A large capacity filter should be installed after the air receiver to remove contamination, oil vapors from the air