Pumps Technology2

8/12/2019 Pumps Technology2

http://slidepdf.com/reader/full/pumps-technology2 1/71

3/13/2014 1

PUMPS TECHNOLOGY

GENERA L COURSE FOR ENGINEERS

For more PPT presentations: ebooks.com-http://www.y

http://www.y-ebooks.com/









3/13/2014 2

INTRODUCTION

PUMPSDEFINATION

PUMPS HISTORYPUMPS

APPLICATIONS

PUMPSTERMINOLGY



3/13/2014 3

MAIN TOPICS

PUMPS CLASSIFICATIONPUMPS APPLICATION

MAJOR COMPONENTS OFCENERIFUGAL & RECIPROCATINGPUMPS

CALCULATION & PERFORMANCEOPERATION & TROUBLESHOOTING



3/13/2014 4

PUMPS

Pumps are machinesthat are used to moveliquids from one placeto anther throughpipelines.Pumps handle allkinds of liquids.

Pumping rates canvary from a fewgallons to amillion/day



3/13/2014 5

Pumps are made ofdifferent materials indifferent sizes and

shapesPumps are thesecond commonmachine in the worldPumps are used in allpower plant



3/13/2014 6

Pumps applications

Examples of pumpsapplication in powerplants:

Boiler circulationFeed waterFuel oilChemical FeedCondensateCirculation waterVacuum



3/13/2014 7

THEORY OF PUMPS

Pump HeadStatic Suction LiftStatic Section HeadTotal Static HeadStatic DischargeHead

CavitationsNet Positive SuctionHead



3/13/2014 8

A) Pump Heads

Hss & Hsd : representthe pressure heads atsuction and dischargeports of the pump ifthe flow rate is zeroHss= h1+Pa/y

Hsd= h2+Pb/yHst=hsd - hss



3/13/2014 9

PUMPS

TERMES

Fig. a Suction Lift – Showing StaticHeads in aPumping SystemWhere the Pumpis Located Abovethe SuctionTank. (StaticSuction Head)



3/13/2014 10

PUMPSTERMS

Fig. b SuctionHead – ShowingStatic Heads in aPumping SystemWhere the Pumpis Located Belowthe Suction Tank.(Static SuctionHead)



3/13/2014 11

Suction Head

Suction HeadA Suction Head existswhen the liquid is takenfrom an open toatmosphere tank wherethe liquid level is abovethe centerline of thepump suction,

commonly known as aFlooded Suction.



3/13/2014 12

Suction Lift

Suction Lift existswhen the liquid istaken from an open

to atmosphere tankwhere the liquidlevel is below thecenterline of the

pump suction



3/13/2014 13

Pump Heads

Pump suction head (hs)Hs represents the pressurehead at the pump suctionnozzle

Hs= Pa/y+h1-v2/2g-hLshL=f(L/D)v2/2g

F=friction factor

D=diameterV=velocityL= length of pipe up to the pointrequired



3/13/2014 14

Pump Heads

Pump delivery head (hd)The pump delivery headrepresents the pressure

head at the pumpdischarge nozzle (d)Hd= Pb/y+h2-v2/2g+hLd



3/13/2014 15

Head Total Dynamic

Total Dynamic Head(TDH) = Elevation(ft) + Friction (ft)



3/13/2014 16

Atmospheric Pressure

The Pressure of theAtmosphere on theEarth

AtmosphericPressure at SeaLevel



3/13/2014 17

Absolute Pressure

Absolute Pressure isthe sum of the availableatmospheric pressureand the gage pressurein the pumping systemAbsolute Pressure(PSIA) = GaugePressure +Atmospheric PressureAbsolute Pressure =150 PSIG (GaugePressure) + 14.7 PSI(Atmospheric Pressure)= 164.7 PSIA



3/13/2014 18

Pump capacity

Capacity (Q) is normally expressed in gallonsper minute (gpm). Since liquids are essentiallyincompressible, there is a direct relationshipbetween the capacity in a pipe and the velocityof flow. This relationship is as follows:Q=A*V

Where

A = area of pipe or conduit in square feet.V = velocity of flow in feet per second.



3/13/2014 19

PUMPS CLASSIFICATION

Dynamic pump

Displacement



3/13/2014 20

CENTRIFUGAL CLASSIFICATION

AXIAL FLOW MIXED FLOW

RADIALL

CENTRIFUGAL





3/13/2014 22

Axial Flow - a centrifugal pump in which thepressure is developed by the propelling orlifting action of the vanes of the impeller onthe liquid.

Radial Flow - a centrifugal pump in which thepressure is developed wholly by centrifugalforce.

Mixed Flow - a centrifugal pump in which thepressure is developed partly by centrifugalforce and partly by the lift of the vanes of theimpeller on the liquid.



3/13/2014 23

CENTERIFUGAL PUMP

OPERATE ON THEPRINCIPLE OF

CENTERIFUGAL

FORCE

DRIVEN BYELECTRIC MOTOR

STEAM TURBINEGAS TURBINE



3/13/2014 24

A xial Flow



3/13/2014 25

Radial Flow Types

The flow parallel tothe axis (the centerline) of the shaft

Axial flow

Single stage Multistage



3/13/2014 26

AXIAL FLOW

Axial flow pumps are propeller pumpThe arrangement of the pump is usuallyvertical

Ability to operate at high speedLift capacity, discharge and the head arelowThere are to type: single stage &multistage



3/13/2014 27

RADIAL FLOW

Flow at 9 0 angle tothe center line of theshaft



3/13/2014 28

MIXED FLOW

Mixed flow pump is apump that uses bothaxial-flow and radial flowcomponents in one

impellerThe head developed bycentrifugal force andpartly by the lift of theimpeller vanes on the

liquidIs used mainly on lowhead high capacity.



3/13/2014 29

MAJOR COMPONENTS OFCENTERIFUGAL PUMP

SUCTION INLETIMPELLERSHAFTCASING(HOUSING)DISCHARGEOUTLET

BEARINGSSEALS



3/13/2014 30

Centrifugal Pump Components

The two maincomponents of acentrifugal pump arethe impeller and thevolute .The impeller producesliquid velocity and thevolute forces the liquid

to discharge from thepump convertingvelocity to pressure.



3/13/2014 31

CENTRIFUGAL PUMP



3/13/2014 32

CENTERIFUGAL PUMPS



3/13/2014 33

1. SUCTION INLET

Liquid enter the pump through the suctionThe side of flow entering is calledUPSTREAM

The discharge side is called theDOWNSTREAMThe pipeline that carries the liquid isbolted or screwed the suction flange



3/13/2014 34

1)SUCTION INLET



3/13/2014 35

SUCTION NOZZLE

DIRECT FLOW

RADIAL AXIAL MIXED

SUCTION

SINGLE ENTERY DOUBLE ENTERY



3/13/2014 36

2. IMPELLER & SHAFT

Impeller is the main part of a centrifugalpump.It move the liquid through the pumpIt is vary considerably in designIt can be classified according to specificspeed



3/13/2014 37

IMPELLER TYPES

There are three types,depend upon thepump size or type of

liquid and requireddischarge pressure.OpenPartially open

Enclosed





3/13/2014 39

IMPELLER CAVITATION

Cavitation : The formation and collapsing of

bubbles inside the pump casing



3/13/2014 40

COLLAPSE OF VAPOR





3/13/2014 42

3. PUMP CASING

Centrifugal pump casing (Housing)encloses the rotating partsThe suction and discharge nozzles areusually in the lower casingThe upper have can be easily lifted forinspectionThere are many types of casing, ex.Volute and split.



3/13/2014 43

4. DISCHARGE OUTLET

The liquid leave the pump under pressurethrough the discharge outletThe discharge outlet is the downstreamside of the pumpThe discharge flange is located at thelarge end of the volute.





3/13/2014 45

Wearing Rings

Centrifugal pumps contain rotating impellerswithin stationary pump casings. To allow theimpeller to rotate freely within the pump casing,

a small clearance is designed to be maintainedbetween the impeller and the pump casing. Tomaximize the efficiency of a centrifugal pump, itis necessary to minimize the amount of liquid

leaking through this clearance from the highpressure or discharge side of the pump back tothe low pressure or suction side.



3/13/2014 46

Some wear or erosion will occur at the pointwhere the impeller and the pump casingnearly come into contact This wear is dueto the erosion caused by liquid leaking

through this tight clearance andother causes. As wear occurs,the clearances becomelarger and the rate of leakage increases.

Eventually, the leakage could becomeunacceptably large and maintenance would berequired on the pump. To minimize the cost ofpump maintenance, many centrifugal pumps aredesigned with wearing rings.



3/13/2014 47

STUFFING BOXESIn almost all centrifugal pumps, the rotating shaftthat drives the impeller penetrates the pressureboundary of the pump casing. It is important thatthe pump is designed properlyto control the amount of liquid that leaks along

the shaft at the point that the shaftpenetrates the pump casing. There are many dif ferent methods of sealing the shaft penetration ofthe pump casing. Factors considered whenchoosing a method include thepressure and temperature of the fluid being pumped, the size of the pump, and the chemical andphysical characteristics of the fluid being pumped.One of the simplest types of shaft seal is thestuffing box



3/13/2014 48

The s tu ff ing bo x is a cylindrical space in the pumpcasing surrounding the shaft. Rings of packingmaterial are placed in this space. Packing ismaterial in the form of rings or strands that is placedin the stuffing box to form a seal to control the

rate of leakage along the shaft. The packingrings are held in place by a gland. The gland is, inturn, held in place by studswith adjusting nuts. As the adjusting nuts are tightened, they move the gland in andcompress the packing. This axial compression causes the packing to expand radially, forming atight seal between the rotating shaft and the insidewall of the stuffing box.





3/13/2014 50

CENERIFUGAL PUMPOPERATION



3/13/2014 51

LANTERN RING

The leakage rate can be adjusted by tighteningand loosening the packing gland. Lantern Ring It is not always possible to use a standardstuffing box to seal the shaft of a centrifugal

pump. The pump suction may be under avacuum so that outward leakage is impossible orthe fluid may be too hot to provide adequatecooling of the packing. These conditions requirea modification to the standard stuffing box.One method of adequately cooling the packing under these conditions is to include alantern ring.



3/13/2014 52

LANTERN RING

A lantern ring is a perforated hollow ringlocated near the center of the packing boxthat receives relatively cool, clean liquid fromeither the discharge of the pump or from an

external source and distributes the liquiduniformly around the shaft to provide lubricationand cooling. The fluid entering the lantern ringcan cool the shaft and packing, lubricate thepacking, or seal the joint between the shaft

and packing against leakage of air into thepump in the event the pump suction pressure isless than that of the atmosphere



3/13/2014 53

MECHANICAL SEAL

Is used in highpressure pumpsIs used in chemical

pumps and liquidssuch as gasoline,acids and ammonia.There are two types:

Rotating sealStationary seal



3/13/2014 54

ADVANTAGES OF DISADVFUGALPUMPSANTAGE OF CENTER

They are the least expensive of pump tobuildThey have only one moving part.They do not need a lot of maintenance

The main disadvantage is must be primedbefore they are started



3/13/2014 55

II. DISPLACEMENT PUMPS

IntroductionDisplacement pumptypes

Reciprocating &Rotary Pumps

Major partsDescribe the operation

Advantages &DisadvantagesDrawing symbol



3/13/2014 56

INTRODUCTION

Rotary &Reciprocating pumps are positivedisplacement pumps.Positive displacement pump can beclassified by the type of motion of internalelementsThe motion may be either rotary or

reciprocating



3/13/2014 57

Basic Types

PISTON VANE

GEAR

DISPLACEMENT



3/13/2014 58

a) Rotary pumps

Rotary pumps

External Internal Lobe Screw



3/13/2014 59

Major Parts of Rotary Pumps

The major parts of rotarypumps are the: – Suction Inlet – Pumping Element/Drive

shaft* – Housing – Discharge Outlet

– * The pumping elements ineach of the four types aredifferent.



3/13/2014 60

Gear pumps



3/13/2014 61

1)External pumps

The pumping elementin external pumpconsist of two gearwheels inside thehousing.One gear is driven bythe motor (Drive gear)The driven gearconnected directly tothe drive shaft



3/13/2014 62

External Pumps Operation



3/13/2014 63

External Pumps Operation

From the figure : – Liquid enters the pump through the suction

inlet.

– As the gears rotate, liquid is trapped betweenthe gear teeth and the housing.

– In suction side, volume expand

– In discharge, volume decrease – When the gear teeth mesh, the liquid is

squeezed out through the discharge outlet



3/13/2014 64

2) Internal Gear Pumps

This design consist ofinternal spur gear andexternal housing.

As a power is appliedto either gear, themotion of the gearsdraws fluid from tankand forced it aroundboth sides of thecrescent seal (sealbetween S & D)





Ad t g & Di d t g f R t



3/13/2014 67

Advantages & Disadvantages of Rotarypumps

High pressure capability (up to 10,000 psi)Small, compact size.High volumetric efficiency.Small change in efficiency through thedesign pressure range

Great flexibility of performance.Only the disadvantage is the gear must fitclose together.



3/13/2014 68

Reciprocating Pumps

IntroductionMajor Parts

Pump OperationMain typesDrawing Symbol

Advantages &Disadvantages



3/13/2014 69

Introduction

Reciprocating pumps, like rotary pumps,are positive displacement pumps.Reciprocating means to move with a backand forth motion.The main parts are piston and cylinderThe main types : – Axial design – Radial design





Pumps Technology2

Documents