Irrigation Training Centrifugal and Submersible Pumps

8/19/2019 Irrigation Training Centrifugal and Submersible Pumps

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CENTRIFUGAL AND

SUBMERSIBLE PUMPSDon Davis, CIC


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Pump Applications

Centrifugal Pumps• Booster applications

• Open water applications (25’ maximum suction lift)

• !allow well applications

• "pplications w!ere electrical lines can’t #e

installe$ in open water

Submersible Pumps• Deep well applications

•

Open water applications with suction lifts above25’

• Open water applications with excessive elevation

requiring higher output pressure

• Applications where a visible pump is unesirable


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Centrifual Pump !peration

%ow $oes a pump&'pump

"n airtig!t intae creates a vacuum $uringimpeller rotation'

*+' psi of atmosp!eric pressure exists at sealevel' -!is is t!e pressure pus!ing water intot!e impeller' ("tmosp!eric pressure $ecreases * psi for eac!

2... feet increase in elevation) -!e spinning impeller creates inertia,

increasing pressure an$ $isc!arging t!e water'


4/41

"#at$s Insi%e&


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Internal Components

/lectrical motor 0oltage, p!ase varies #1 application

Impeller

Plastic, cast iron, #rass material options otating impeller pus!es water against pump

casing or volute an$ increases pressure'

"$$ more impellers to increase pressure an$

create a multi3stage pump (t!at is !ow a 4!orsepower pump in a *... foot $eep wellcan suppl1 water)


6/41

Pump Terminolo'

%orsepower Power reuire$ to lift 66,... poun$s or 65.

gallons of water * foot in one minute

7eet of %ea$

" *’ !ig! column of water contains t!epotential energ1 of *’ of !ea$

-!e *’ !ig! column of water will !ave apressure of .'+66 PI at t!e #ase

7eet of !ea$ $ivi$e$ #1 .'+66 8 PI

PI x 2'6* 8 feet of !ea$


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E(ample

!hat is the pressure require to pump water

to the top of a 25’ column"

25’

25’ # 2$%& ' &($) PS*

(r

25’ x $+%% ' &($) PS*

,ow much pressure o we have at the top

of the column"


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Ma(imum Suction Lift

%ow $oes t!is a9ect pump applications Convert *+' PI at sea level to feet of !ea$:

*+' PI x 2'6* 8 66'; feet of !ea$

Insu


9/41

Pump Cur)e Data

Curve provi$es performance $ata for aspeci>c pump Curve notes ?P@ t!e pump provi$es at a

speci>c feet of !ea$

election of pump s!oul$ #e "BO0/ 1ourspeci>c $esign point on t!e curve

election of a pump in t!e center of t!e curveis i$eal

1stem $esign criteria is critical for pump

selection


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Pump Cur)e * Centrifual


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Pump Cur)e * Su+mersi+le


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Calculatin Feet of ,ea%

Vertical elevations: measure feet

Horizontal distances: measure friction loss

PSI, convert to feet


13/41

7riction Aoss -a#les

-riction loss tables

provie the PS* lossper &(( feet of pipe

at a given flow$

.arger iameter piperesults in lower PS*

loss at the same

flow$


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Calculatin Feet of ,ea%

"ssume s1stem reuirements are *2 ?P@ at 5. PI:

uction lift (assume su#mersi#le for t!is example) .’ /levation c!ange from pump to !ig!est point on site *’

@ainline friction loss (5..’ of * C% +., *2 ?P@) 6'’ 6'6 PI lossE*.. feet F 5.. feet mainline 8 *' PI

*' PI F 2'6* 8 6'’ Desire$ operating pressure of 5. PI converte$ to feet:

**5'5’

5. PI F 2'6* 8 **5'5’

-otal 7ee$ of %ea$ **'6’ Gill nee$ to use t!e * !p su#mersi#le from t!e pump curve


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Pump Selection

e$ucing feet of !ea$ reuirements ma1 allow selectionof smaller pump' -ae t!e previous example:

uction lift (assume su#mersi#le for t!is example).’

/levation c!ange from pump to !ig!est point on site *’ @ainline friction loss (5..’ of * H C% +., *2 ?P@)

*.'2’

.'; PI lossE*.. feet F 5.. feet mainline 8 +'+5 PI

+'+5 PI F 2'6* 8 *.'2’ Desire$ operating pressure of +5 PI converte$ to feet:

*.6';’

+5 PI F 2'6* 8 **5'5’

=ew total feet of !ea$: *6*'*’ Can use t!e 4 !p su#mersi#le from t!e pump curve


16/41

Proper Plum+in * Suction

@ost pumps fail $ue to improperplum#ing on t!e suction si$e' @inimie >ttings an$ #en$s ie t!e suction line *32 pipe sies larger t!an

t!e inlet t!rea$ sie' @ae it as s!ort as possi#le' Jse a straig!t, level lengt! of pipe into t!e

suction' (lengt! 8 53*. times t!e pipe

$iameter) 7oot valveEstrainer must #e in clean water'


17/41

Proper Plum+in *Disc#are Disc!arge plum#ing tips:

Jse galvanie$ pipeE>ttings

Install an isolation valve to ai$ in priming

Pressure relief valveEpriming port s!oul$ $irectl1 a#ove

$isc!arge Install a union for maintenance purposes

"$$ >ltration to all non3pota#le water sources

Install a pressure gauge

Install a !ig! temperature sensor, low pressure sensor


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Avoi using P/0 for irect connections to

centrifugal pumps$ ,eat generate

uring operation or no1flow situations will

cause problems

Proper installation using

galvani3e fittings$


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Su+mersi+le PumpInstallation

Pump sle to incluean inlet strainer an

outlet well seal

*nstall union in

ischarge line near

shore for maintenance

purposes

*nclue safet4 line for

retrieval

*nstall chec valve in

suction line


21/41

Su+mersi+le PumpInstallation Pump sle$ can #e constructe$ from P0C pipe

an$ >ttings' Jse galvanie$ (or stainless steel) >ttings

#etween t!e pump an$ $isc!arge pipe' Pump

start3up torue GIAA unscrew t!e pump fromP0C >ttingsK

Gell seal prevents torue spin ecure wiring to $isc!arge pipe' Aeave excess

wire at s!ore line for maintenance purposes' Install isolation valve upstream of pump for

trou#les!ooting purposes'


22/41

Pump Sle% or Slee)e

" casing is man$ator1 for a su#mersi#le pumpK -!e water intae is locate$ a#ove t!e motor'Placing t!e pump in a casing forces all of t!eintae water to pass over t!e motor for cooling

purposes' " pump left in open water GIAA over!eat' Cistern or $oc applications: install pump insi$e

a sleeve'


23/41

!n*Deman% Pump S'stems

Jse in situations w!ere a continuousl1pressurie$ mainline is not $esire$

Does not reuire pressure tan

installation Pump activates onl1 w!en irrigation

controller signals operation


24/41

!n*Deman% Pump Controls

Pump tart ela1 2 wire pumps can use a stan$ar$ P

6 wire pumps reuire a control #ox wit! startcapacitor

efer to manufacturer’s ca#le siing c!arts to$etermine wire gauge reuirements


25/41

Pressuri-e% Pump S'stems

Jse in situations w!ere a P is notfeasi#le @ultiple controllers using same pump

Luic couplers or !1$rants $esire$ on site Controller an$ pump are not in close

proximit1

pecial reuirements: !elter large enoug! to accommo$ate

pressure tan(s)

Drain to exterior for P0


26/41

Pressuri-e% Pump Controls

Si3e blaer tan at minimum one gallon rawown for each

6P7 of pump capacit4$ 7ultiple tans can be installe in series

for higher 6P7 requirements$ Set tan pressure at 2 PS*

below pump cut1in pressure$

8an tee allows for pressure switch9 pressuregauge9 pressure relief valve9 rain valve9 an chec

valve installation in a compact location$


27/41

.arie% GPM Re/uirements

C1cle top 0alve estricts pump output to matc! ?P@ $eman$'

"s $eman$ $ecreases, t!e C1cle top 0alveincreases #ac pressure on t!e motor'

Increase$ #ac pressure $ecreases t!e gallonreuirement' -!is $ecrease in gallonreuirement re$uces t!e loa$ on t!e motor,resulting in re$uce$ amperage $raw an$t!erefore power consumption'

Pressure $ownstream remains constant wit!int!e allowa#le Mow rates for t!e particular unit'

B1pro$uct of C1cle top 0alve operation is t!eelimination of water !ammer'


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.arie% GPM Re/uirements

0aria#le 7reuenc1 Drive @otor (07D) 0aries t!e freuenc1 an$ voltage supplie$ to

an electric motor' "s freuenc1 (or !ert)increases, motor P@ increases'

G!ile a stan$ar$ motor will operate at fullP@ regar$less of ?P@ $eman$, a 07D !aspotential for energ1 savings w!en operating ata lower freuenc1 $uring lower ?P@ $eman$'

6 p!ase motor reuire$


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Ca)itation

7ormation of air #u##les in a liui$ t!atoccurs w!en t!e pressure falls #elow t!evapor pressure'

-!e vapor will turn #ac to a liui$ an$Nexplo$e’, causing $amage to t!ecomponents'


30/41

Pre)entin Ca)itation

Increase net positive suction !ea$ (=P%)availa#le #1: Increase t!e $iameter of suction line

@inimie >ttings in suction line e$uce Mow rate t!roug! pump

e$uce suction lift elevation

e$uce suction line $istance

Create arti>cial pressure on t!e $isc!arge #1installing smaller $iameter $isc!arge pipe ort!rottling valve


31/41

Ca)itation Damae

Brass Impeller

T +l # ti All


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Trou+les#ootin 0 AllMotors @O-O -"- -OO O7-/=

C!ec setting on pressure switc!' eset limitor replace switc!'

Damage$ or $efective c!ec valve will not!ol$ pressure'

C!ec for waterlogge$ pressure tan' C!angeair c!arge or replace tan'

/xamine s1stem for leas an$ repair asnecessar1'


33/41

@O-O J= CO=-I=JOJA C!ec pressure switc! for wel$e$ contacts

a$Qust settings as necessar1 Pump intae #loce$

C!ec valve stuc close$

Aow water level or loss of prime

Aea in $isc!arge

Gorn pump: s1mptoms similar to low waterlevel or $rop pipe lea re$uce pressure switc!setting an$ pump will s!ut o9 in$icates warnparts


34/41

PJ@P D/AI0/ AI--A/ O =O G"-/

Aow line voltage to motor Incomplete priming of pump

"ir loc in suction line

Drop pipe !as $isconnecte$ from pump

Aow water level Clogge$ or $efective foot valve E strainer

Gorn pump parts or plugge$ impeller


35/41

Circuit Brea1er2 Fuse2 !)erloa%Trips

C!ec for correct line voltage' Over!eate$ control or starter ma1 reuire

ventilation'

Defective control #ox' Defective motor or ca#le' Gorn pump or motor'


36/41

Insulation Resistance Test

O!m rea$ing R 5..,... in$icatesinsulation $amage' Git! power o9 an$ motor lea$s $isconnecte$,

test resistance #etween an1 one of t!e motorlea$s an$ euipment groun$' " normal o!mvalue for all lea$s in$icates t!e motor is notgroun$e$ an$ t!e ca#le insulation is not$amage$' =ew motor (wit!out $rop ca#le): 2.,...,... S

o!ms

/xisting motor (wit!out $rop ca#le): *.,...,...S o!ms

=ew motor in well: 2,...,... S o!ms

T


37/41

"in%in Resistance Test

efer to manufacturer’s c!arts for o!mvalues' 2 wire motors: measure resistance from line

to line 6 wire motors: measure resistance to B

(main win$ing) an$ to (start win$ing) If all o!m values are normal, motor is not

groun$e$ an$ ca#le insulation is not $amage$

If an1 one value is R normal, t!e motor iss!orte$

If an1 one value is U normal, t!e win$ing orca#le is open E #a$ splice


38/41

Control Boxc!ematic


39/41

Control Bo(*!#m Tests

Power O77 for o!m tests: Overloa$s s!oul$ o!m less t!an .'5

Capacitor s!oul$ o!m near *5,...

ela1 coil s!oul$ o!m +5..3... ela1 contact s!oul$ ero o!m

tart an$ run capacitors s!oul$ o!m near eroan$ t!en move towar$ in>nit1


40/41

Control Bo(*AmperaeTests @otor un$er loa$ for amperage tests:

e$ lea$ current s!oul$ start !ig! an$ t!enfall to manufacturer’s c!art rea$ing' Blacan$ 1ellow lea$ current s!oul$ not excee$c!art rea$ing' ela1 or switc! failure: Constant !ig! re$ lea$

current an$ overloa$ tripping

Open run capacitor: lower t!an normal re$ lea$

amps, an$ !ig!er t!an normal 1ellow an$ #laclea$ amps

7aile$ start capacitor or open switc! E rela1: re$lea$ current is not momentaril1 !ig! at starting


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Re)ie3

Gater source t1pe @inimum an$ maximum Mow, ?P@ Desire$ pressure at sprinlers

0ertical elevationVwater line to pump 0ertical elevationVpump to !ig!est point @ainline (sie, t1pe, lengt!)

uction line (sie, t1pe, lengt!) Gell $ept!, 1iel$, water level, pump set

$ept! Gell pump %P, ?P@

Irrigation Training Centrifugal and Submersible Pumps

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