Chapter 08 - Electricity for Water Supply.pdf

8/11/2019 Chapter 08 - Electricity for Water Supply.pdf

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IntroductionIntroduction

Water is the most important of all ourWater is the most important of all our

natural resourcesnatural resourcesA ready supply of water is a vital need forA ready supply of water is a vital need for

every farmevery farm Thee should be an adequate supply ofThee should be an adequate supply of

water and it must be pure for its intendedwater and it must be pure for its intended

use.use.


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Sources of WaterSources of Water

Surface waterSurface water

rivers, lake, farmrivers, lake, farmponds, andponds, and

reservoirsreservoirs

Underground waterUnderground water

wells and springswells and springs


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Classifications of WellsClassifications of Wells

According to Depth of WellAccording to Depth of Well

Shallow WellsShallow Wellslifting water is 22 feet or lesslifting water is 22 feet or less Deep WellsDeep Wellslifting water is 22 feet andlifting water is 22 feet and

aboveabove


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According to the Type of ConstructionAccording to the Type of Construction

Dug wellDug wellshallow, susceptible to pollutionshallow, susceptible to pollution Driven wellDriven wellshallow, safe, economicalshallow, safe, economical

Bored wellsBored wellsshallow, susceptible to pollutionshallow, susceptible to pollution Tubular WellsTubular Wellsdeep, safedeep, safe

Drilled WellsDrilled Wellsdeep, safedeep, safe


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Daily Water RequirementsDaily Water Requirements

UseUse Gal/dayGal/day

Each member of the familyEach member of the family 50 or 250 minimum per50 or 250 minimum per

householdhousehold

Each horseEach horse 1212

Each cow producing milkEach cow producing milk 4040

Each dry cow or steerEach dry cow or steer 1212

Each hogEach hog 44

Each sheepEach sheep 22

Each 100 chickenEach 100 chicken 66

Each 100 turkeysEach 100 turkeys 1818

Garden hose, in. nozzleGarden hose, in. nozzle 300300

Garden hose, 1/2 in. nozzleGarden hose, 1/2 in. nozzle 200200


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General Pump ClassificationsGeneral Pump Classifications

RotaryRotaryIt uses gears, vanes, lobe, or screw toIt uses gears, vanes, lobe, or screw totrap and convey fluid from inlet to the outlet oftrap and convey fluid from inlet to the outlet ofthe pump.the pump.

ReciprocatingReciprocatingIt uses a back and forth motionIt uses a back and forth motion

of mechanical parts such as piston orof mechanical parts such as piston ordiaphragms to pressurize the fluid.diaphragms to pressurize the fluid.

CentrifugalCentrifugalIt uses a centrifugal force impartedIt uses a centrifugal force imparted

to the fluid by one or more rotating elementsto the fluid by one or more rotating elementscalled impellers to increase the kinetic energycalled impellers to increase the kinetic energyand pressure energy of the fluid.and pressure energy of the fluid.


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Submersible-Type

Surface-Type

Examples of Centrifugal Pumps


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Types of Pump Commonly Used forTypes of Pump Commonly Used for

Pumping WaterPumping Water

Centrifugal PumpCentrifugal PumpA typeA type

of pump with impellersof pump with impellersrotating inside a closedrotating inside a closedcasing which draws watercasing which draws water

into the pump through ainto the pump through acentral inlet opening andcentral inlet opening andforces water out through aforces water out through a

discharge outlet at thedischarge outlet at theperiphery of the housing byperiphery of the housing bymeans of centrifugal force.means of centrifugal force.


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Mixed Flow PumpMixed Flow Pump

A type of pump whichA type of pump whichcombines some of thecombines some of thefeatures of bothfeatures of bothcentrifugal and the axialcentrifugal and the axialflow pump and in whichflow pump and in whichhead is developed partlyhead is developed partlyby the centrifugal forceby the centrifugal forceand partly by the loft ofand partly by the loft of

the vanes on the water.the vanes on the water.


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Applications of Electric PumpApplications of Electric Pump

SystemSystem Domestic WaterDomestic Water

supplysupplyAgroAgro--IndustrialIndustrial

Water SupplyWater Supply Irrigation WaterIrrigation Water

SupplySupply


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Pump for Domestic Water Supply


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Pumps TermsPumps Terms

CapacityCapacityIt is the amount of discharge ofIt is the amount of discharge of

a pump at maximum efficiency.a pump at maximum efficiency. DischargeDischargeIt is the volume of waterIt is the volume of water

pumped per unit time.pumped per unit time.


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HeadHead

It is the amount of energy requiredIt is the amount of energy required

to lift and move the water from anyto lift and move the water from anyarbitrary datum.arbitrary datum.

Friction HeadFriction Head -- It is the equivalent headIt is the equivalent headrequired to overcome the friction caused byrequired to overcome the friction caused bythe flow through the pipe and pipe fittings.the flow through the pipe and pipe fittings.

Static Suction HeadStatic Suction HeadIt is the verticalIt is the verticaldistance from the free suction water level todistance from the free suction water level tothe center line of the pump.the center line of the pump.

Static Discharge HeadStatic Discharge HeadIt is the verticalIt is the verticaldistance from the centerline of the pump todistance from the centerline of the pump tothe discharge water level.the discharge water level.


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HeadHead

Ht = Hs + Hd + Hf

where:

Ht - total head, m

Hs - suction head, m

Hd - discharge head, mHf - friction head, m


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Water HorsepowerWater Horsepower

It is the theoretical power required by the pumpIt is the theoretical power required by the pumpin pumping water.in pumping water.

WHP = Q H / 273

where:

WHP - water horsepower, hp

Q - discharge, m3/hr

H - vertical lift, m


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Brake HorsepowerBrake Horsepower

It is the power required to drive the pump shaftIt is the power required to drive the pump shaft

BHP = WHP / p

where:

BHP - brake horsepower, hpWHP - water horsepower, hp

p - pump efficiency, %


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Pump EfficiencyPump Efficiency

It is the ratio of the power output to theIt is the ratio of the power output to the

power input of the pump.power input of the pump.

p = WHP x 100 / BHP

where:

p - pump efficiency, %WHP - water horsepower, hp

BHP - brake horsepower, hp

O ll S t Effi i f W t


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Overall System Efficiency of WaterOverall System Efficiency of Water

PumpPump

Pump TypePump Type Overall SystemOverall System

EfficiencyEfficiency

New electric motor andNew electric motor andwater pumpwater pump

9595

Reconditioned pump andReconditioned pump and

motor unitsmotor units6060


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CavitationCavitationIt is the formation of cavities filledIt is the formation of cavities filled

with water vapor due to local pressure drop andwith water vapor due to local pressure drop andcollapse as soon as the vapor bubbles reachcollapse as soon as the vapor bubbles reach

regions of high pressure.regions of high pressure.

PrimingPrimingIt is the filling up of the pump withIt is the filling up of the pump withwater to displace or evacuate the entrapped airwater to displace or evacuate the entrapped air

through a vent and create a liquid seal inside thethrough a vent and create a liquid seal inside the

casing.casing.

F t t C id i thF t t C id i th


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Factors to Consider in theFactors to Consider in the

Selection of PumpSelection of Pump HeadHead--Capacity of the WellCapacity of the Well

Initial CostInitial Cost

Space requirementSpace requirement

Type of power unit and pumpType of power unit and pumpcharacteristicscharacteristics

Storage Capacity, rate of replenishment,Storage Capacity, rate of replenishment,and well diameterand well diameter

Other possible uses of pumpOther possible uses of pump

P LP L


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Pump LawsPump Laws

QQ11 / Q/ Q22 = N= N11 / N/ N22

HH11 / H/ H22 = N= N1122 / N/ N22

22

BHPBHP11 / BHP/ BHP

22 = N= N

11

33 / N/ N22

33

where:

Q - discharge

N - rpm

H - head

BHP - brake horsepower

G t i ll Si il PG t i ll Si il P


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Geometrically Similar PumpsGeometrically Similar Pumps

QQ22 / Q/ Q11 = (D= (D22 / D/ D11))33

HH22 / H/ H11 = (D= (D22 / D/ D11))22

BHPBHP22 / BHP/ BHP11 = (D= (D22 / D/ D11))55

where:

Q - discharge

D - impeller diameter

H - head

BHP - brake horsepower


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Pump Controller


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Magnetic StarterSwitch

Push Button

Switch


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Pressure Tank Pressure Switches


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Heater for Water Tank


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Float Switch


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ReferencesReferences

Brown, R. 1956. Farm Electrification. McGrawBrown, R. 1956. Farm Electrification. McGraw--HillHillBook Company. New York. 367pp.Book Company. New York. 367pp.

James, L. 1988. Principles of Farm Irrigation SystemJames, L. 1988. Principles of Farm Irrigation SystemDesign. John Wiley & Sons. USA. 543pp.Design. John Wiley & Sons. USA. 543pp.

PAES. 2001. Centrifugal PumpPAES. 2001. Centrifugal Pump--Specifications.Specifications.

Philippine Agricultural Engineering standards Volume I.Philippine Agricultural Engineering standards Volume I.AMTEC, CEAT, UPLB, College, Laguna. AAMTEC, CEAT, UPLB, College, Laguna. A--142 to A142 to A--148.148.

PAES. 2001. Centrifugal, Mixed Flow, and AxialPAES. 2001. Centrifugal, Mixed Flow, and Axial--FlowFlow

PumpPump--Specifications. Philippine Agricultural EngineeringSpecifications. Philippine Agricultural Engineeringstandards Volume I. AMTEC, CEAT, UPLB, College,standards Volume I. AMTEC, CEAT, UPLB, College,Laguna. ALaguna. A--150 to A150 to A--168.168.

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Chapter 08 - Electricity for Water Supply.pdf