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Introduction What is a pump?Pump is a machine which enables liquid to flow from a region of low pressure to one of high pressure.Enables liquid to flow from a low level to a higher level.Used to increase flow rate.

Centrifugal Pump

Pumping System Pumping system is a process of making liquid /fluid flow from one place to other

Objectives of pumping system

Transfer liquid from source to destination.

Circulation of a liquid around system.

Improve work efficiency.

Types of Pumps Positive displacement Pump These pumps operate by forcing a fixed volume of fluid from inlet pressure section of the pump into the discharge zone of the pump.These pumps are generally larger than equal capacity dynamic pumps. Types of positive displacement pumps are:Reciprocating pump: displacement by reciprocating of piston plunger. Used only for viscous fluids and oil wells.Rotary pumps: displacement by rotary action of gear or vanes.Used for special services in industry.

Dynamic PumpsThese pumps operate by developing a high liquid velocity and converting the velocity to pressure in a diffusing flow passage. They are of to types :Centrifugal Pump: A centrifugal pump is a rotodynamic machine that converts mechanical energy into hydraulic energy by centrifugal force on liquid.Axial Pump: These type of pumps consist of propeller (an axial impeller) in a pipe . That's why they are also called propeller pumps.

Centrifugal pumpCentrifugal pump works on the principle that when a certain mass of liquid is made to rotate along the impeller from the central axis of rotation, it impresses a centrifugal head. It causes water to move radially outward at higher velocity and causes the water to rise to a higher level. The motion of water is restricted by casing of pump, it result into pressure build up. The change in angular momentum of liquid during its flow result into increase in pressure head .

HistoryThe first machine that could be characterized as a centrifugal pump was a mud lifting machine which appeared as early as 1475 by Italian engineer Francesco di Giorgio Martini. True centrifugal pumps were not developed until the late 17th century, when Denis Papin built one using straight vanes. The curved vane was introduces by British inventor John Appold in 1851.

Pump Terminology

1.ImpellerImpeller is one o the most important part of the pump. It transmits energy in form of velocity to liquid(water).basically it increases the velocity of incoming water by providing 2000-4000rpm.These are used to determine the efficiency of pump.Types of ImpellerOpen ImpellerVanes(Blades) are designed to meet a given range of flow conditions. In open impeller vanes are attached to central hub, without any form,sidewall,or shroud, and are mounted directly onto a shaft. Open impellers are structurally weak .They are used in small diameter, inexpensive pumps.

2.Closed ImpellerThe closed impeller has both a back and front wall for maximum strength. They are used in large pumps. The closed impeller type is the most widely used type of impeller for handling clear liquids. They rely on close clearance wear rings on the impeller. The wear ring separates the inlet pressure from the pressure from pressure within the pump, reduces axial load and maintains efficiency of pump.

3. Partially open or Semi closed .....ImpellersThis type of impeller incorporates a back wall (shroud) that serves to stiffen the vanes and adds mechanical strength. They are used in medium diameter pumps and with liquids containing small amount of suspended liquid. They provides higher efficiency than open impellers.

Components of ImpellerEye Eye is the part of pump from where the incoming water enters the impeller.

Hub Area around the eye is called hub.

Vanes Here the water comes in contact with blades or vanes of impeller and is thrown outward

Casing Collects the water and confines it in order to convert the velocity to pressure and directs it to the discharge.Components of casingVolute: It refers to the enclosing pump casings internal passageway which is shaped like the expanding spiral of snail. It collects flow from impeller, diffuses kinetic energy into pressure and guides the flow to the pump discharge nozzle.Stripping edge : diverts water by 180 degree apartDischarge: factors affecting discharge pressure amount of water being discharged.Speed of impeller.

Centrifugal Impeller

Thicker the impeller-more waterLarger the diameter -more pressureIncrease the speed-more water and pressureImpeller VanesDiameter of the ImpellerEye of the ImpellerWater EntranceThickness of the impeller Shaft Transfers torque from motor to impeller during pump start up and operation

It subjected to different types of stress

The shaft position horizontal or vertical ,defines weather pump is considered as horizontal pump or vertical pump

Two impellers in seriesSame amount of water but increased pressure.Placing impellers in series increases the amount of head produced.

Direction of FlowWorking Mechanism of Centrifugal PumpIt is the simplest equipment in any process plant.Energy changes occur by virtue of impeller and volute.Liquid is fed into the pump at the center of rotating impeller and thrown outward by centrifugal force.The conversion of kinetic energy into pressure energy supplies the pressure difference between the suction side and delivery side of the pump.

PrimingTo develops negative pressure at the eye of impeller ,the pump should initially filled with the fluid This process is known as priming.Types of Priming;

Self priming

Not self priming

Most of the pumps are not-self primingDefinition for the pump head:

Head is an indirect measurement of pressure that does not depend on the fluid density.

That means for low viscous fluids, the pump performance can be uniquely defined in terms of head.

In other words, the pump performance, in pressure, depends on the density of the fluid being pumped, but when this performance is expressed in head, the pump performance is independent of the fluid being pumpedHydraulic losses

Pumps are designed trying to achieve a no pre-rotation condition close to the best efficiency point, since this condition minimize shock-losses. In other words, shock losses increase as we move away from the BEP. Leakage and recirculation of fluid .inside the impeller Causes :Hydraulic losses including:Diffusion loss due to divergence, or convergenceFluid shock loss at the inletMixing and eddying loss at the impeller dischargeTurning loss due to turning of the absolute velocity vector Separation lossesFriction lossesMechanical losses Advantages of Centrifugal PumpSimple in construction and cheap.

Handle liquid with large amounts of solids.

No valves involved in pump operation.

Maintenance costs are lower.

Disadvantages of Centrifugal PumpCannot handle highly viscous fluids efficiently.

Cannot be operated at high heads.

Maximum efficiency holds over a narrow range of conditions.

Seal & BearingMechanical seal Best method for preventing the leakageConsist of two parts, rotating element connected to pumpShaft & stationary element attached with pump casingEach element have highly polished surfaceBEARINGThe second lead cause of pump breakdown is bearing failure most bearing are fails due to static overload ,lubricant failure,wear, corrosion or overheating.CavitationCavitation implies a dynamic process of formation of bubbles inside the liquid, their growth and subsequent collapse as the liquid flows through the pump. Cavitation occurs whenever the local static pressure falls below the vapor pressure of liquid. This results in formation of vapor's .The vapor cavity changes the effective shape of flow passage, thus altering the local pressure field due to the flow may become unsteady.

The unsteadiness my cause entire flow to oscillate and machine to vibrate.

It reduces the performance of pump or turbine rapidly.Prevention of CavitationIt can be avoided if the pressure everywhere in the machine is kept above the vapor pressure of the operating liquid.

NPSH is the measure of difference between the max possible pressure in given flow and the pressure at which the liquid will start flashing over to vapor. Larger the NPSH less will be cavitation

Blowers and FansFans are designed to handle air or vapor. They provide ventilation for commercial and industrial purposes.Types of fan and blowers :

Centrifugal FanRotating impeller increases air velocityAir speed is converted to pressureHigh pressures for harsh conditionsHigh temperaturesMoist/dirty air streamsMaterial handlingCategorized by blade shapesRadialForward curvedBackward inclined

Centrifugal Fans Radial fanAdvantagesHigh pressure and tempSimple designHigh durabilityEfficiency up to 75%Large running clearances

Disadvantages Suited for low/medium airflow rates only

Centrifugal Fan Forward CurveAdvantagesLarge air volumes against low pressureRelative small sizeLow noise levelDisadvantagesNot high pressure / harsh serviceDifficult to adjust fan outputCareful driver selectionLow energy efficiency 55-65%

Centrifugal Fan Backward InclinedAdvantagesOperates with changing static pressureSuited for high flow and forced draft servicesEfficiency >85%DisadvantagesNot suited for dirty airstreamsInstability and erosion risk

Axial FanWork like airplane propeller: Blades create aerodynamic liftAir is pressurizedAir moves along fan axis Popular with industry: compact, low cost and light weightApplicationsVentilation (requires reverse airflow)Exhausts (dust, smoke, steam)

Axial Fans Propeller fans

AdvantagesHigh airflow at low pressureLittle ductworkInexpensiveSuited for rooftop ventilationReverse flowDisadvantagesLow energy efficiencyNoisy

Axial Fans Tube axial fans

AdvantagesHigh pressures to overcome duct lossesSuited for medium-pressure, high airflow ratesQuick accelerationSpace efficientDisadvantagesExpensiveModerate noiseLow energy efficiency 65%

BlowersDifference with fansMuch higher pressures 12,000 cfm

Thank You for Listening

Prepared byNITYA SINGH CM14222MANISH KUMAR- CM14223RITAM GHOSH - CM14225SANYOGITA CM14226SHAURYA SINGH MALIK CM14227SHIVANG CM14228SHIVANSH SHARMA CM14229