Book-Hydraulics Pump Seminar

(1)

E

EFFICIENT BYFFICIENT BYDDESIGNESIGN

&

L

(2)

I

t’s unwise to pay too much, but it’s worse to

pay too little.

W

hen you

pay to

o much

, yo

u l

ose a l

ittl

e

money, that’s all.

W

hen you pay too

li

ttle, you sometimes

los

e

everything, because the thing you bought was

incapable of doing the thing it was bought to do.

The common law of business balance

prohibits paying a little and getting a lot —

it can’t be done.

If you deal with the lowest bidder, it is well

to add something for the risk you run, and if

you do that you will have enough to pay for

something better.

”

John Ruskin

“ “

(3)

I

t’s unwise to pay too much, but it’s worse to

pay too little.

W

hen you

pay to

o much

, yo

u l

ose a l

ittl

e

money, that’s all.

W

hen you pay too

li

ttle, you sometimes

los

e

everything, because the thing you bought was

incapable of doing the thing it was bought to do.

The common law of business balance

prohibits paying a little and getting a lot —

it can’t be done.

If you deal with the lowest bidder, it is well

to add something for the risk you run, and if

you do that you will have enough to pay for

something better.

”

John Ruskin

“ “

(4)

M

M ou

ounntitinng C

g Con

onffiigguurrat

atiion

on . . . .

. . . . . . . .

. . . . . . .3

. . .3

Q

Q uuaalliity F

ty Fea

eatu

turres

es . . . .

. . . . . . . .

. . . . . . . .4

. . . .4

TTer

erm

miinnol

olog

ogy

y . . . .

. . . . . . . .

. . . . . . .6

. . .6

FFac

act F

t Fin

indin

ding to D

g to D ete

eterrmi

minne Pum

e Pump Choi

p Choice

ce . . .

. . . . . .

. . . .13

.13

Se

Sellec

ectitinng t

g thhe Pu

e Pum

mp

p . . . .

. . . . . . . .

. . . . .18

.18

M

M uulltitipl

ple Pu

e Pum

mps

ps . . .

. . . . . .

. . . . .20

. .20

Spe

Specciiffiic Sp

c Spee

eed

d . . . .

. . . . . . . .

. . . . . . . .22

. . . .22

AA ffffiinniity L

ty Laaws

ws . . .

. . . . . .

. . . . . . .23

. . . .23

Pu

Pump-E

mp-Ennggiinne Sel

e Selec

ectition . . .

on . . . . . .

. . . . . .

. . . .24

.24

En

Enggiinne D

e D er

erat

ate G

e G uuiidel

deliinnes

es . . . .

. . . . . . . .

. . . . .25

.25

AA vver

erag

age E

e Ellec

ectr

triic M

c M otor

otor Li

Liffe

e . . . .

. . . . . . . .

. . . . . . .2

. . .2 66

G

G uuiide to O

de to O pti

ptimu

mum E

m Ellec

ectr

triic M

c M otor

otor Lif

Life

e . . . .

. . . . . . . .

. . . . 27

27 El

Elec

ectr

triic M

c M otor

otor Com

Compar

pariisson

ons

s . . . .

. . . . . . . .

. . . . . . .2

. . .2 88

El

Elec

ectr

triic Con

c Contr

trol P

ol Pan

anel

el DD at

ata

a . . .

. . . . . .

. . . . .

. . . . . .

. . . . .29

. .29

Ty

Typic

pical

al AA uuto Vac

to Vacuuuum Pr

m Priim

me

e . . . .

. . . . . . . .

. . . . . . .30

. . .30

M

M at

ater

eriial

als

s of C

of Con

onsstr

truuct

ctiion

on . . . .

. . . . . . . .

. . . . .3

.3 11

B-10 Bearing Calculation . . . .33

Pump Performance Curves

. . .

. . . . . .

. . . . . . .34

. . . .34

. . .

. . . . . .

. . . . . . .35

. . . .35

. . .

. . . . . .

. . . . . . .36

. . . .36

. . .

. . . . . .

. . . . . . .37

. . . .37

. . .

. . . . . .

. . . . . . .38

. . . .38

. . .

. . . . . .

. . . . . . .39

. . . .39

. . .

. . . . . .

. . . .40

.40

. . .

. . . . . .

. . . . . . .4

. . . .4 11

. . .

. . . . . .

. . . . . . .42

. . . .42

. . .

. . . . . .

. . . . . . .4

. . . .4 33

. . .

. . . . . .

. . . . . . .4

. . . .4 44

Specif

Specific

icati

ation G

on G ui

uide

de –

– Cor

Corne

nell Sol

ll Solids

ids HH an

andlin

dling Pum

g Pumps . .

ps . . . .

. . . .

. . 44 55

Lubrication Instructions . . . .47

Sta

Starrt-u

t-up Ch

p Chec

eck Li

k Lisst t . . . .

. . . . . . . .

. . . . .50

.50

Pu

Pump T

mp Trrou

oubl

bles

eshhoot

ootiinng G

g G uuiide

de . . . .

. . . . . . . .

. . . . . .5

. .5 11

AA iir

r Lea

Leaks

ks . . .

. . . . . .

. . . . . . .52

. . . .52

Pa

Packi

cking

ng, , W

W ear

ear Ri

Ring

ngs

s an

and

d Coupl

Couplin

ing A

g A lilign

gnmen

ment .

t . . .

. . . .

. . .53

.53

Pu

Pum

mp Ca

p Carre

e . . .

. . . . . .

. . . . . . .54

. . . .54

2 . 2 .5 5 WW BB 4 4 WW BB 5 5 WW BB 5 5 YYBB 4 4 RBRB 6 6 RBRB 6 RB-Various RPM 6 RB-Various RPM 4 4 HH HH 4 x 4 x 14T 4 x 4 x 14T 6 N H 6 N H TTAA 6 N 6 N HH PP-VPP-V arariiouous s RPMRPM

T

ab

le o

f C

o

nte

nts

(5)

Cornell Pump Company

P.O. Box 6334 Portland, Oregon 97228 Phone: (503) 653-0330 Fax: (503) 653-0338

(6)

M o unting Co nfigurations

Horizontal Close-Coupled (CC). Economical, compact and efficient.

Horizontal Frame (F). Driver flexibility.

Vertical Frame (VF). Driven by flexible shaft from motor above pump.

Redi-Prime ®

Run-dry, automatic dry prime and re-priming capabilities. SAE Engine Mount (EM).

Ideal for remote locations or where electrical power is not available.

Trailer or skid mounted.

Base-Coupling-Guard Mounted Horizontal Frame Unit.

Can be mounted with a motor or other driver on a common base.

Vertical Close-Coupled (VM). This vertical style is desirable

where space is limited.

Vertical Coupled (VC). Minimal floor space required.

Standard "P" base motor used.

(7)

Co rnell Q uality Feature s

MODULAR BEARING FRAME

REPLACEABLE SHAFT SLEEVE BACK PULL-OUT DESIGN

FOR EASE OF MAINTENANCE

FULLY MACHINED IMPELLER

WITH DOUBLE CURVATURE VANES EXTERNAL HYDRAULIC BALANCE LINE

SMOOTH CONTOURED SUCTION FOR IMPROVED HYDRAULIC PERFORMANCE DOUBLE VOLUTE DESIGN

STANDARD ON LARGER SIZES RIGID, HEAVY WALLED

CONSTRUCTION LARGE, DEEP STUFFING BOX FOR EXTENDED PACKING LIFE AND MINIMUM ADJUSTMENTS (MECHANICAL SEALS OPTIONAL) GENEROUSLY SIZED BEARINGS

TO MAXIMIZE B-10 BEARING LIFE HEAVY, STRESS PROOF

STEEL SHAFT

REPLACEABLE, RECESSED WEAR RINGS

(8)

T H E EX T ERN A L H Y D RA U L IC BA L A N CE LIN E

To lower pressure in the

stuffing box (or seal chamber) and to attempt to limit the inherent axial force created by the impeller, traditional centrifugal pump designs use large holes bored through the impeller. Cornell has a more effective method –THE EXTERNAL HYDRAULIC BALANCE LINE.

High pressure liquid from the volute passes through the hub ring clearances into the cavity between the stuffing box and the impeller. Liquid returns via the balance line to

the region of lower pressure at the pump inlet. This method reduces turbulence, improves hydraulic efficiency, increases the life of packing, mechanical seals and bearings – provides positive control of axial forces. It also reduces wear because sand is not trapped behind the impeller, near the shaft.

CO RN ELL A D V A N CED D ESIG N

FEA TURES TH E D O UBLE VO LUTE SYSTEM

The Double Volute System enables Cornell single stage, end-suction centrifugal pumps to easily handle large volume and high pressure jobs.

As the impeller adds energy to the fluids, pressure increases around the periphery of the volute. On single volute pumps, the increasing pressure acts against the impeller area and creates unbalanced radial forces. By contrast, the Double Volute System effectively balances these forces around the impeller to reduce shaft flexure and fatigue.

Cornell’s “DVS” design keeps shafts from breaking, extends the life of packing and mechanical seals, wear rings and bearings – maintaining high hydraulic efficiency.

Balanced axial forces

Reduced Pressure Area

Sand and silt flushed out CORNELL METHOD External Hydraulic Balance Line Area of turbulence Holes bored in impeller Sand and silt buildup TRADITIONAL METHOD Unbalanced axial forces

CORNELL DOUBLE VOLUTE Radial thrust is offset and balanced by the double volute design.

Cutwater #1

(9)

PPU M

U M PPSS

Pump-Pump- A mechanical device that convertsA mechanical device that converts

mechanical forms of energy into hydraulic energy. mechanical forms of energy into hydraulic energy.

Pum

Pump p CCllasassifsifiicacatitions-ons- Generally pumps can beGenerally pumps can be classified into two classifications – positive classified into two classifications – positive di

dissplplaacecemement nt aand nd cecentntrriifufuggaall..

Posit

Positiive ve DDiisplacesplacemement Punt Pumpsmps-- Operate byOperate by reducing the volume of space within the pump reducing the volume of space within the pump that the liquid can occupy. In a reciprocating that the liquid can occupy. In a reciprocating pump the piston forces the liquid from the pump the piston forces the liquid from the cylinder into the discharge line.

cylinder into the discharge line.

C

Ceentrntriifugafugal Pumpsl Pumps-- Move liquids by increasingMove liquids by increasing their speed rather than displacing or pushing their speed rather than displacing or pushing them. The vanes do work on the fluid to increase them. The vanes do work on the fluid to increase tthe vhe veellocitocity wiy witthout hout dedecrecreaassiing tng the prehe pressssururee. Th. Thiiss increased velocity is then recovered in the casing increased velocity is then recovered in the casing as

as iincrncreeasaseed d prpreessssururee..

C

Ceentrntriifugafugal Forcel Force-- According to Websters, is thatAccording to Websters, is that force which tends to impel a thing, or parts of a force which tends to impel a thing, or parts of a thing outward from the center of rotation. thing outward from the center of rotation.

Sump-Sump- A hydraulic structure that acts as aA hydraulic structure that acts as a reservoir from which single or multiple pumps, reservoir from which single or multiple pumps, arranged in parallel, may draw water.

arranged in parallel, may draw water.

Vortex-Vortex-The phenomenon by which air enters aThe phenomenon by which air enters a submerged suction pipe from the water surface. submerged suction pipe from the water surface. Usually a cause of poor pump performance when Usually a cause of poor pump performance when the suction pipe is not adequately submerged. the suction pipe is not adequately submerged.

Manifold-Manifold- A hydraulic structure used to distributeA hydraulic structure used to distribute water under pressure. Can be used to supply fluid water under pressure. Can be used to supply fluid to or receive fluid from a parallel arrangement of to or receive fluid from a parallel arrangement of multiple pumps.

multiple pumps.

ELE

ELECTR

CTRICA

ICA LL

Volt-Volt- A uniA unit t of eleof elecctrtricaical l potepotentintiaal. A volt l. A volt iis s thethe driving force which causes a current of 1 ampere driving force which causes a current of 1 ampere to flow through a resistance of 1 ohm.

to flow through a resistance of 1 ohm.

Ampere-Ampere- A unit of electrical current. The unitA unit of electrical current. The unit used to specify the movement of electrical charge used to specify the movement of electrical charge per unit time through a conductor.

per unit time through a conductor.

Kilowatt-Kilowatt-The unit commonly used toThe unit commonly used to

describe electrical power. 1 Kilowatt is equal describe electrical power. 1 Kilowatt is equal to approximately 1.34 horsepower.

to approximately 1.34 horsepower.

Power-Power- The raThe rate of doite of doing wng workork..

Pow

Power Factorer Factor-- The percentage of apparentThe percentage of apparent electrical power (Volts x Amps) that is actually electrical power (Volts x Amps) that is actually available as usable power.

available as usable power.

Ohm-Ohm- The practical unit to measure electricalThe practical unit to measure electrical resistance. Resistance of a circuit in which a resistance. Resistance of a circuit in which a potential difference of one volt produces a potential difference of one volt produces a current of one ampere.

current of one ampere.

Terminology

TYPICAL TYPICAL CENTRIFUGAL CENTRIFUGAL PUMP IMPELLER PUMP IMPELLER In centrifugal pumps, In centrifugal pumps, water enters the pump water enters the pump and travels into the and travels into the impe

impelllleer tr throughrough th thehe impeller eye. In general, impeller eye. In general, the larger the impeller the larger the impeller eye, the greater the eye, the greater the volume in gallons volume in gallons per minute. per minute. DISTANCE DISTANCE BETWEEN

BETWEEN SHROUDSHROUDSS

IMP

IMPELLEELLERR EYEEYE

EXA

EXA MM PLE:PLE: ReReciciprprocaocatitinngg

EXA

EXA MM PLE:PLE: CenCentrtrififugugalal Single Single or or mumultipleltiple design design The

Thesseecacann bebessiinglengle

a

andnd multmulti-i-sstagtageeopeopenn or

or closcloseedd impeimpelllleersrs Piston Piston Plunger Plunger Diaphragm Diaphragm R

Raadialdial FFlowlow Mi

Mixexedd FFlowlow

Ax

Axiaiall FFlowlow R

Rototaarryy GeGeaarr R

Rototaarryy SScrecreww R

(10)

perfect vacuum is zero. Absolute pressure of the perfect vacuum is zero. Absolute pressure of the atmosphere at sea level is 14.7 psi (0 psi gauge). atmosphere at sea level is 14.7 psi (0 psi gauge).

Vapor Pr

Vapor Presessursuree-- The pressure exerted when aThe pressure exerted when a ssolid or olid or liliquid is quid is in in eequiliquilibrium brium witwith ith its s owownn vapor. Vapor pressure is a function of the vapor. Vapor pressure is a function of the substance and of the temperature.

substance and of the temperature.

Vacuum-Vacuum- Frequently used in referring to pressuresFrequently used in referring to pressures below atmospheric. Vacuum is commonly expressed below atmospheric. Vacuum is commonly expressed iin in i nchenches s of of memerrcurcuryy. 14. 14.7 ps.7 psi i aattmosmosphepherriicc

pressure equivalent to 30 inches of mercury at pressure equivalent to 30 inches of mercury at sea level.

sea level.

Head-Head- The vertical height of a static column of The vertical height of a static column of liquid corresponding to the pressure of a fluid at liquid corresponding to the pressure of a fluid at that point. Head can also be considered as specific that point. Head can also be considered as specific work (FT. LB./LB.) necessary to increase the pressure, work (FT. LB./LB.) necessary to increase the pressure, velocity or height of a liquid to some value.

velocity or height of a liquid to some value.

Pote

Potentintial Headal Head-- (Energy of position) The work(Energy of position) The work required to elevate a weight to a certain height required to elevate a weight to a certain height above some datum or reference plane.

above some datum or reference plane.

Bri

Brititissh Theh Thermarmal Unil Unit (Bt (BTUTU)-)- The The aamount mount ofof heat required to raise the temperature of one heat required to raise the temperature of one pound of water from 63 to 64 degrees Fahrenheit. pound of water from 63 to 64 degrees Fahrenheit. BTU’s are the unit commonly used to express BTU’s are the unit commonly used to express the potential energy of fuels used in internal the potential energy of fuels used in internal combustion engines.

combustion engines.

S

Shut-hut-off off HeaHead-d- Is the head generated by a pumpIs the head generated by a pump with the discharge valve closed (pump running at with the discharge valve closed (pump running at zero capacity).

zero capacity).

Stati

Static Pressc Pressurure e HHeead-ad- (Energy per pound due to(Energy per pound due to pr

preessssururee)). The he. The heiight ght tto whio which lch liiquiquid cad can n be be rraaiisseedd by a given pressure.

by a given pressure.

Ve

Vellociocity Heaty Head-d- (K(Kiinenetiti c ec enenergy pergy per r pound)pound). The. The vertical distance a liquid would have to fall to vertical distance a liquid would have to fall to a

acqcquiuire the re the vevellocitocity y ““V”.V”.

Be

Berrnoullnoullii’s T’s Theheoreoremm-- The sum of the three typesThe sum of the three types (elevation, pressure and velocity) of energy (heads) (elevation, pressure and velocity) of energy (heads) at any point in a system is the same at any other at any point in a system is the same at any other

point in the system assuming no friction losses point in the system assuming no friction losses or

or tthe he peperfrformormaance nce of of work.work.

S

Statatitic Sc Suction Luction Liift-ft- The veThe verrttiicacal l didissttaance nce iin fn feeeett,, when the source of supply is below the pump, when the source of supply is below the pump, from the surface of the liquid to the pump from the surface of the liquid to the pump centerline.

centerline.

Sta

Statitic Sc Suctiuction Hon Heead-ad- When the liquid supply isWhen the liquid supply is above the pump. The vertical distance from the above the pump. The vertical distance from the pump centerline to the surface of the liquid. pump centerline to the surface of the liquid.

SUCTION SUPPLY SUCTION SUPPLY

OPEN TO ATMOSPHERE OPEN TO ATMOSPHERE

with Suction Lift with Suction Lift

SUCTION SUPPLY SUCTION SUPPLY

OPEN TO ATMOSPHERE OPEN TO ATMOSPHERE

with Suction Head with Suction Head

NPSH NPSHAA = = PPBB + + LLHH - (V - (VPP + + hhff)) NPSH NPSHAA = = PPBB - (V - (VP P ++ LLSS + + hhff )) L LSS P PBB P PBB L LHH C CLL C CLL

(11)

S

Suctiuction Hon Heeadad-- (hs) exists when the liquid supply(hs) exists when the liquid supply level is above the pump centerline or impeller eye. level is above the pump centerline or impeller eye. The total suction head is equal to the static height The total suction head is equal to the static height or static submergence (in feet) that the liquid or static submergence (in feet) that the liquid supply level is above the pump centerline, less all supply level is above the pump centerline, less all suction line losses including entrance loss, plus any suction line losses including entrance loss, plus any pr

preessssururee((a vaa vacuum cuum aas s iin a conden a condensnseer r hothotwewelll l bebeiingng a

a neneggaattiiveveprpreessssururee) ) eexixissttiing ang at t tthe he ssuctuctiion supplon supplyy ssourourcece. Ca. Caututiion – on – eeveven n whewhen n tthe lihe liquiquid supplyd supply level is above the pump centerline the equivalent level is above the pump centerline the equivalent of a lift will exist if the total suction line losses (and of a lift will exist if the total suction line losses (and va

vacuumcuum eeffffeect) ct) eexcexceeed thd the e posposiittiive ve ssttaattiic c ssuctuctiionon head. This condition can cause problems head. This condition can cause problems particu-llaarlrly whey when handlin handling vong volatilatille e or or vivissccous ous liliquiquidsds..

Sta

Statitic Dc Diischascharrgge e HHeead-ad- Vertical distance fromVertical distance from pump centerline to the free surface of the liquid in pump centerline to the free surface of the liquid in a discharge tank or point of free discharge.

a discharge tank or point of free discharge.

Total D

Total Diischascharrgge e HHeead-ad- (hd) Is the sum of:(hd) Is the sum of: ((11)) Static discharge head.Static discharge head.

((22)) AlAll l pipipiping ang and fnd frriictiction lon lososssees s on ton thehe discharge side including straight runs of discharge side including straight runs of pipe, losses at all valves, fittings, strainers, pipe, losses at all valves, fittings, strainers, control valves, etc.

control valves, etc.

((33)) Pressure in the discharge chamber (if it is aPressure in the discharge chamber (if it is a closed vessel).

closed vessel).

((44)) Losses at sudden enlargements (as in aLosses at sudden enlargements (as in a condenser water box).

condenser water box).

((55)) Exit loss at liquid discharge (usuallyExit loss at liquid discharge (usually

assumed to be equal to one velocity head at assumed to be equal to one velocity head at discharge velocity).

discharge velocity).

((66)) Plus any loss factors that experiencePlus any loss factors that experience indicates may be desirable.

indicates may be desirable.

L

LSS == MaximuMaximum static sum static suction liction lift in feetft in feet.. L

LHH == MinimuMinimum static sum static suction hection head in feetad in feet.. h

hff == Friction loss in Friction loss in feet in suctfeet in suction pipe at ion pipe at required capacityrequired capacity.. P

PBB == BaromeBarometric presstric pressure, in feet abure, in feet absolutsolute.e. V

VPP == Vapor Vapor pressure of pressure of the liquid the liquid at maximum at maximum pumpingpumping temperature, in feet absolute.

temperature, in feet absolute. P

P == PressuPressure on sure on surface orface of liquf liquid in clid in closed suosed suction tction tank,ank, in feet absolute. in feet absolute. CLOSED CLOSED SUCTION SUPPLY SUCTION SUPPLY

with Suction Lift

NPSH NPSH_A_A = = P - P - (V(V_P_P₊₊ LL_S_S + + hh_f_f)) L L_S_S P P C C_L_L CLOSED CLOSED SUCTION SUPPLY SUCTION SUPPLY

with Suction Head

NPSH NPSH A A = P + L = P + LHH - (V - (VPP + + hhff)) P P L L_H_H C C_L_L TOTAL TOTAL STATIC STATIC HEAD HEAD STATIC STATIC DISCHARGE DISCHARGE HEAD HEAD STATIC STATIC SUCTION SUCTION HEAD HEAD TOTAL TOTAL STATIC STATIC HEAD

HEAD STATICSTATIC DISCHARGE DISCHARGE HEAD HEAD STATIC STATIC SUCTION SUCTION LIFT LIFT

(12)

Work- The transference of energy by a process involving the motion of the point of application of a force, as when there is movement against a resisting force or when a body is given acceleration; it is measured by the product of the force and the displacement of its point of application in the line of action.

H Y D RA U L ICS

Hydraulics- The study of fluids at rest or in motion.

Fluid- A substance which when in static equilibrium can not sustain tangential or shear forces. This differentiates fluids from solids. However, in motion, fluids can sustain shear forces because of the property of viscosity. A fluid can be a liquid or a gas.

Viscosity- The existence of internal friction or the internal resistance to relative moti on of the fluid particles with respect to each other. The viscosities of most liquids vary appreciably with changes in temperature, whereas the influence of pressure change is usually negligible. Some liquids have viscosities which change with agitation.

Newtonian- A liquid is Newtonian or a “true fluid if its viscosity is unaffected by agitation as long as the temperature is constant. Example: Water or mineral oil.

Thixotropic- A liquid is thixotropic if its viscosity decreases with agitation at constant temperature. Example: Glues, asphalt, greases, molasses, etc.

Dilatant- A liquid is dilatant if the viscosity increases with agitation at constant temperature. Example: Clay slurries and candy compounds.

Density- Density is the mass per unit volume of a substance. It is unaffected by the variations in gravity or acceleration.

Specific Weight- The weight per unit volume of a substance. The two terms are frequently used interchangeably, though this is incorrect.

Specific Gravity- The ratio of its density (or specific weight) to that of some standard substance. For liquids, the standard is water (1.0 sp. gr.) at sea level and 60°F.

Pressure- The force exerted per unit area of a fluid. According to Pascal’s principle, if pressure is applied to the surface of a fluid, this pressure is transmitted undiminished in all directions.

Atmospheric Pressure- The force exerted on a unit area by the weight of the atmosphere. The standard atmospheric pressure at sea level is 14.7 psi.

Gauge Pressure-Is pressure measured relative to local atmospheric pressure. Atmospheric pressure is zero gauge.

Absolute Pressure- The sum of atmospheric pressure and gauge pressure. The absolute pressure in a

3.3 FT.

2.3 FT.

1.54 FT.

GASOLINE WATER MOLASSES

SP. GR. = 0.7 1 PSI SP. GR. = 1.0 1 PSI SP. GR. = 1.5 1 PSI EX A M P LE:

1 a t mo sph ere = 14.7 psi ~ 34 f eet w a t er 34/14.7 = 2.31

p si =

2.31

x SP. G R. He a d in Fe et

Since water weighs .0361 pounds per cubic inch, a column of water one square inch in area and one (1) foot high will weigh .433 pounds. To increase the pressure at the bottom of the column to one (1) psi requires a 2.31 foot high column of water.

(13)

Total Head- (Formerly called Total Dynamic Head). Equal to the total discharge head (hd) minus the total suction head (hs) or plus the total suction lift.

Net Positive Suction Head Required- (NPSHR) The losses from the suction connection to the point in the pump at which energy is added,

generally, through the impeller vanes. Determined by test and dependent on pump design, pump size, and operating conditions.

Net Positive Suction Head Available- The energy, above the vapor pressure of the fluid, available at the pump suction to push the fluid into the pump. Note:NPSHA depends on the system layout and

must always be equal to or lar ger than the NPSH R.

Cavitation- A result of inadequate NPSHA. When pressure in the suction line falls below vapor

pressure of the liquid, vapor is formed and moves with the liquid flow. These vapor bubbles or

“cavities” collapse when they reach regions of higher pressure on their way through the pump. The violent collapse of vapor bubbles forces liquid at high velocity against the metal, producing surge pressures of high intensity on small areas. These pressures can exceed the compressive strength of the metal, and actually blast out particles, giving the metal a pitted appearance.

The other major effects of cavitation are drops in head, flow and efficiency.

Pipe Friction- The system loses pressure when the water flowing through the piping encounters

resistance. For example, friction occurs along the pipe walls because of roughness. Pressure loss also occurs because of turbulence induced by valves,

fittings and changes of section. The Cornell “Condensed Hydraulic Data” book has typical pipe, valves, and fitting Head Loss Tables.

Capacity- Actual pump delivery (usually in gallons per minute in the U.S.A.).

Horsepower- Power delivered while doing work at the rate of 550 ft-lb per second or 33,000 ft-lb per minute, .706 BTU’s/sec. or .746 kilowatts.

Hydraulic Horsepower- (Water Horsepower) The rate at which a pump adds useful energy to a fluid.

Brake Horsepower- Total power required by a pump to do a specified amount of work. Brake horsepower equals Hydraulic Horsepower plus mechanical and other losses.

EFFICIEN CY

Of a Pump Driver- The percentage of input horsepower that is converted to usable brake horsepower by the pump driver.

Of a Pump- The percentage of brake horsepower applied to the pump shaft that is converted to usable water horsepower by the pump. Bearing and seal losses are usually deducted from

horsepower.

Rating Curves- (Pump Curve) The most

important aspect of any discussion on centrifugal pumps. A graphical representation of a pump’s performance, including NPSH requirements, horsepower requirements, etc. over its entire operating range.

CAVITATION

EFFECT ON PUMP CAPACITY

CAVITATION NORMAL PERFORMANCE WITH SUFFICIENT NPSHA H – Q H E A D — F T . CAPACITY — GPM CUT OFF POINT 100 0 H E AD – C AP A_C I T Y H E A D — F T . CAPACITY — GPM ₅₀₀

(14)

System Curve- A graphical representation of the relationship between the Total Head and the flow rate for a given fluid system.

Simple System Curve- Friction loss increases proportionally to the square of the capacity or velocity.

TYPICA L CURVES

Four typical curves may be classed as follows: 1.Steady Rising Curveor a rising head capacity characteristic is a curve in which the head rises

continuously as the capacity is decreased. The rise from best efficiency point to shut-off is about 10 to 20%. Pumps with curves of this shape are used in parallel operation because of their stable characteristics.

2. Drooping Curvecharacteristic is a curve in which the head capacity developed at shutoff is less than that developed at some capacities. When pumps with drooping characteristics are run on throttling systems, operating difficulties can occur since the system friction curve can intersect the head capacity curve at two points. These pumps will also only operate in parallel when the operating point is below the shut-off head; therefore, parallel operation should be avoided with this curve

shape.

3. Steep-Rising Curveis one where there is a large increase in head between that developed at design capacity and that developed at shut-off. It is best suited for operati on where minimum capacity change is desired with pressure changes, such as batch pumping or filter systems.

• STABLE • O.K. IN PARALLEL OPERATION STEADY RISING H – Q H E A D — F T . GPM H – _Q • GOOD PERFORMANCE • MAXIMUM Q • STABLE AT HEADS BELOW SHUT-OFF HEAD DROOPING H – Q H E A D — F T . GPM H – Q 100 0 1 10 H – Q H – Q H – Q H E A D — F T . B H P CAPACITY — GPM B RA K E H O R S E P O W E R 500 100 0 H E A D — F T . CAPACITY — GPM ₅₀₀ 100 0 H E A D — F T . CAPACITY — GPM NPSHR 500 1 10 90 0 0 B H P B H P E F F I C I E N C Y % E F F . 25 N P S H R F T .

(15)

4. Flat Curverefers to a characteristic in which the head varies slightly with capacity, from shut-off to design capacity. When wide fluctuations of capacity occur with nearly constant pressure requirements this is the pump best used.

• LITTLE RISE OVER RANGE

• GOOD FOR CHANGING Q WITH LITTLE HEAD CHANGE FLAT H – Q H E A D — F T . GPM H – Q • SHUT -OFF 140-150% OF BEP HEAD • STABLE

• GOOD FOR PARALLEL OPERATION

• FILTER SERVICE • SMALL Q CHANGE

FOR VARIABLE HEAD STEEP RISING H – Q H E A D — F T . GPM H – Q

IN GENERAL

In general, it is desirable to choose a pump to operate at maximum efficiency point or slightly to the left of this point. However, with pumps, as with all commodities, the commercial aspect must be considered. Thus pumps are sold to operate over a wide range, even out at the end of the rating curve. If the NPSH available is sufficient to prevent cavitation, the pump will give satisfactor y operation.

(16)

In selecti ng a pump for a particular job, attention should be given to information gathering. Without proper and specific information, proper selection is impossible.

It is often difficult to get information from the user because he either doesn’t know the answers or doesn’t want you to know about his business.

This can waste a lot of time and energy! You must be persistent in getting the informati on, or you may supply the wrong pump, resulting in back charges for restocking and, consequently, a dissatisfied customer.

IT CANN OT BE EMPH ASIZED ENOUGH! YOU MUST ASK THE RIGHT QU ESTIONS.

Questions lead to other questions! Ask questions, even unrelated questions can help! They might trigger other questi ons that are very important to the proper operation of the pump at the site.

• What are the customer’s preferences? • Is he a critic of some particular type of

pump?

• Make of pump – style of pump? • Make of motor – style of motor? • Make of control – style of control?

This will influence your selection. You may have been thinking of a Close-Coupled Centrifugal when the customer was thinking in terms of a Canned Turbine.

• Establish a meeting of minds. • Get the facts. – Weigh them.

Then, make your selection. It may or may not be the type of equipment you first thought of! Ask WHAT the pump is SUPPOSED TO DO.

• What head is required?

• What capacity is required?

• What voltage or power is available?

These can be the openers, but there are many others, depending on the job to be done.

• What is the pumpage? • Is the pumpage hot?

Check the NPSH. Water flashes at 212° F. Check materials of construction. Bronze expands more than iron. It’s possible that a bronze impeller might come off of a particular shaft.

Check fluid viscosity. If the fluid cools off, it may thicken, and raise the horsepower requirement.

• Is the pumpage cold?

Check the NPSH. Ammonia boils at -28° F. Check materials of construction; extreme cold may cause embrittlement.

• Is the pumpage corrosive? • What is its PH level?

Above 7.0 is alkaline, below 7.0 is acidic. Check materials of construction for compatibility with pumpage. Low PH normally requires brass or stainless steel, high PH normally requires iron or stainless steel.

• What is, the specific gravity of the pumpage?

Acids are normally heavy, as are caustics. This means high horsepower.

H HQ BHP BHP BHP SP GR 1.1 SP GR 1.0 SP GR 0.8 Q

(17)

The following check list may help you to ask the questions needed to make the right equipment choices:

1. WH AT IS TH E PUMPAGE? ❏ Vapor pressure

- Does the pumpage have high vapor pressure? - Check NPSH available against NPSH

required.

- Does the pumpage have low vapor? Treat 15 PSI as water.

❏Is the pumpage explosive?

- Check materials of construction.

- Non-ferrous materials should be used to prevent sparking.

- Stainless Steel might be desirable. - Quenched glands.

❏Is the pumpage hazardous to health? - Mechanical seals may be required. - Flushed glands may be required. - Special materials (silver?).

- Special pumps – (sanitary type).

❏ Is the pumpage carrying solids? - Special pump designs required. - Heavier volutes, Impellers, or Vanes. - Recirculation?

- Hard iron or special materials. - High horsepower required. - Reduced heads.

- Pumps should be oversized.

❏ Is the pumpage carrying fibers?

- What percent?

- Is percentage by weight or volume? - In some cases Delta works quite well. - Self-purging action?

- Special pump design required.

❏ Is the pumpage handling food products? - Single Port Impellers.

- Slow speed – 5'/sec. velocity is normal. - V-belt drive.

❏ Is the pumpage a slurry or sand? - Again, extra horsepower is needed. - Extra capacity to take care of losses due

to erosion.

- Some slurries are corrosive as well as abrasive, so check materials.

❏ Is the pumpage aerated?

- Look out for vapor binding.

- Check the source of gas entrainment. - Provide bleed-offs in pump to remove air.

❏ Is the pumpage viscous?

- This can easily lead to high horsepower. - Maximum SSU that can be handled by a

centrifugal pumps is about 5000 SSU. - The head-capacity and efficiency curves

are drastically reduced.

2. WH AT IS THE HEAD REQUIREMENT?

❏ Is the discharge head constant as in the filling of a reservoir? (Hooks are O.K. in this curve)

❏ Is the discharge head variable like with direct

flows into a distribution system? (Hooks in this curve are bad).

❏ Is the pump to work at more than one head?

❏ Check the efficiency curve. A flat curve is desirable so that the pump will be working near maximum efficiency at both locations.

H Q WATER HQ VISCOUS HQ Q H

(18)

❏For more than one head or capacity condition, have you considered:

- Variable-speed pumps, or multiple pumps?

❏Is a rising head curve desirable? For a Boiler Feed or Elevator a flat discharge head is better. - Sprinkler irrigation laterals can be added

without a dramatic change in pressure, like Cornell W & Y series.

❏Is a hook in the discharge head curve

detrimental? Yes, if head is subject to variation.

❏What is the discharge head in terms of - Feet, PSI, PSI G, PSI A absolute, other?

❏Is the discharge head high pressure – 400 to 10,000 feet? If it is, you might consider multi-stage pumps or pumps in series.

❏Is the discharge head medium pressure – 100 to 400 feet? If so, you would use a single stage or multi -stage pump.

❏Is the discharge head low pressure – 0 to 100 feet? In this range you would normally use a single-stage, low speed pump.

3. WHAT IS THE PUMP CAPACITY?

❏Is the pump high capacity? If so, consider mixed

flow or axial flow propeller pumps.

❏Is the pump low capacity? If so, radial or positive displacement pumps should be considered.

❏Is the pump medium capacity? Consider radial or mixed flow pumps.

❏Have you considered dual pumps? Dual pumps have the advantage of stand-by equipment, safety in the event of break down, and usually lower power costs.

❏Is the pump capacity in terms of GPM, cubic foot per second, or second per feet, or barrels

per day. Be sure to check the capacity terms used. There is a chance for error here.

4. WHAT IS THE SUCTION COND ITION THE PUMP USES TO OPERATE AGAINST?

❏ Does it have high suction lift? Medium suction lift? Low suction lift?

❏ Is the suction lift critical? If it is in excess of the NPSH required for the pump, you should move the pump closer to the surface of the liquid, or raise the static head of the pump suction, or increase the suction pipe size, to reduce suction system losses.

❏ Is the submergence sufficient? Best check the NPSH curve. You might consider the installation of a suction umbrella or a floating platform.

❏ How can you tell if the submergence is suffi cient or the suction lift cri tical for the pump selected?Th ere is only one way ; check

the manufacturer’s NPSH curves and compare NPSH A w it h N PSH R.

- Is the suction source critical? Are there

periodic low flows in the water source? Do you have shut-off controls on your pump to prevent damage?

- Is the suction source a sump, a closed tank, a pond, a river, or a pipeline?

- Is the suction tank pressurized, if so, what pressure?

- What pressure can the pump stand?

❏ Is the platform for the pump properly designed?

- Do you have to double bolt the pump? - Is the system apt to go higher during static

and cause water shock which will damage the pump?

- Is the pump mounted at a river location where cross currents could cut the bank out from beneath it and cause the pump to be washed away?

- Are there cross currents creating whirlpools and/or aeration that will cause hydraulic instability in the pump?

(19)

❏What about elevation? Do you know that

suction lift ability decreases approximately one foot for every 1,000 feet above sea level due to decreased atmospheric pressure at higher elevations?

❏Is the suction source subject to variation either in level or quantity?

- Is the suction source subject to debris? - Is there a submergence limitation? - Do you have a critical velocity? - Will a vortex form?

❏Is the suction source properly designed? - Will it be used for more than one pump? - Is the inlet screened?

- Are the screens adequate? - Of proper design?

- Are the intake structures baffled?

5. WH AT ABOU T MOTORS?

❏What type of motor enclosure is required? - ODP, WPI, TEFC, TENV?

❏Is it Explosion Proof?

Is a soft start required or is an across the line start O.K.?

❏Does the user know that motor standards have changed? While 40° C motors were once standard, they are now special. The 60° C motors are now considered standard; however, 75° C motors are standard when a TEFC

enclosure is furnished. 75° C = 167° F.

❏Does the user know how hot 60° C actually is? Does he realize that he can’t hold his hand on a 60° C motor? (60° C = 140° F)

6. WHAT ABOUT TH E TYPE OF PU MP?

❏Has some particular type of pump given better service?

- What has been the history at the site?

❏Does a Horizontal Close-Coupled Centrifugal do the job? They are low cost and don’t require much room!

❏ Does a Horizontal Frame Mounted do the job? Normal use could be with direct, v-belt drive or variable speed.

❏ Does a vertical pump work best?

- A Vertical Frame pump such as a Cornell VC type?

- A Vertical Frame pump of the Line Shaft type (Cornell VF)?

- A Vertical Close-Coupled pump (Cornell VM)?

- A Vertical Can? or Turbine? – Which would be the best choice?

❏What about the pump’s materials of construction?

- What has been the user’s experience? - Should the pump be all Iron, all Bronze,

Stainless Steel, or Cast Steel?

❏ If the pump should be all Iron, what type of

Iron is best?

- Hard/Nodular, Ordinary, High Tensile?

- Which would be the best? Is the user aware of all the various types of Iron?

❏ If all Bronze, what type?

- Standard Commercial, Acid Resistant, Heavy Duty?

❏ If Stainless Steel:

- 400 Series (410-416), 300 Series (304-316), 17-4 PH, Alloy 20?

❏ If all Steel, what kind:

- 1020, 1040, Manganese – Self Hardening?

❏ Besides knowing what particular type of material to use for the pump’s construction, special consideration must also be given to the different metals used for bearings, stuffing boxes, packing, mechanical seals, etc.

7. WHAT ABOUT PIP ING?

❏ Requirements must be met in piping such as how long the pipe should be, and what size of pipe will work.

(20)

- What material should the pipe be constructed of for the type of pumpage? What about the friction coefficient? Is it adequate for the pressure required?

- Will the pipe carry the capacity required? - Is the friction loss too high?

- Do you have a velocity adequate for scouring air/sand?

Provided you have satisfied yourself with the information given, you may then proceed with pump application and selection.

One last question you should ask yourself before providing your bid or recommendation to the customer:

Di d I ask enough quali fyi ng questi ons?

(21)

Se lecting th e Pum p

TO DETERMINE THE SYSTEM TOTAL HEAD ADD THESE FACTORS TOGETHER IN FEET.

3 1 2 7 4 5 6

SUCTION ENTRANCE LOSS SUCTION PIPE FRICTION DISCHARGE PIPE FRICTION SUCTION LIFT MISCELLANEOUS LOSSES (VALVES, ELBOWS, ETC.)

DISCHARGE LIFT NEEDED PRESSURE AT END OF LINE NOTE: BE SURE TO MULTIPLY PRESSURE IN P.S.I. BY 2.31 TO CONVERT TO FEET

T YP ICA L P U M P IN STA L LA T IO N

TOTAL HEAD is the SUM of the following:

1. Suction pipe friction (see Condensed Hydraulic Data Book).

2. Suction lift (vertical distance, in feet, from water surface to center of pump inlet).

3. Suction entrance loss (usually figured at one velocity head plus foot valve losses

4. Discharge pipe friction (Condensed Hydraulic Data Book).

5.Discharge lift (vertical distance, in feet from pump to high point in system).

6.Pressure, in feet, for service intended (pressure, in P.S.I., x 2.31 equals feet of head).

7.Miscellaneous losses, in feet (for valves, elbow, and all other fittings, see Condensed Hydraulic Data Book).

EX A M P LE 1:

For capacity of 320 GPM, total head in feet is determined as follows:

1. .28 Ft. Suction friction (6” steel pipe, 20’ long) 2. 5 Ft. Suction lift

3. 2 Ft. Suction entrance loss

4. 14 Ft. Discharge friction (6” steel pipe,1000’ long) 5. 15 Ft. Discharge lift 6. 100 Ft. (43 P.S.I. x 2.31) 7. 5 Ft. Miscellaneous losses EX A M P LE 2: For capacity of 600 GPM, total head in feet is determined as follows: 1. .89 Ft. 2. 5.00 Ft. 3. 6.90 Ft. 4. 45.00 Ft. 5. 15.00 Ft. 6.100.00 Ft. 7. 17.30 Ft.

H O W T O SEL ECT A CEN TRIFU G A L P U M P

The pump is selected after all the system data has been gathered and computed. The system TOTAL CAPACITY in gallons per minute and TOTAL HEAD in feet must be determined. You should consider suction submergence, NPSH R and A, various speeds, other drives (engine, motor, etc.) and all system conditi on to optimize the selection.

190 Ft. Total Head 141 Ft. Total Head

(22)

SELECTIN G TH E PUM P FO R

6 0 0 G PM @ 19 0 FT. T. H .

At 3600 RPM

Refer to the pump performance curve on page 35. The 4WH 40-2, 3560 RPM handles the head and capacity with 7.00” Impeller at 75% efficiency and 14 ft. NPSH required.

At 1800 RPM

Refer to the pump performance curve on page 41. The 3HA 30-4, 1775 RPM handles the head and capacity with 14” Impeller at 71% efficiency and 8 ft. NPSH required.

SELECTIN G TH E PUM P FO R

320 G PM @ 141 FT. T.H .

Refer to the pump performance curve on page 34. The 2.5 WH, 3525 RPM, handles the head and capacity with 71% efficiency. NPSH required is 11 feet. A 20 horsepower 3525 RPM motor is required with a 6.50” impeller.

NOTES:

1. Required Head and Capacity.

2. Net Positive Suction Head Available/ Required.

3. Pumpage characteristics:

A. Presence of abrasives, size, concentration, specific gravity, other characteristics. B. Viscosity.

C. Temperature.

D. Corrosive qualities.

E. Presence of other impurities or gases. F. Specific Gravity.

G. Vapor Pressure.

4. Service duty cycle.

5. Type of materials and fittings in connected pipe lines.

6. Previous experiences with the system. 7. Acceptable economic life.

8. Desired pump driver and related data. 9. Safety or downtime consideration.

Reference: Hydraulic Institute Standards, 13th edition.

D A TA REQ U I RED FO R M A KIN G A SA T ISFA CT O RY P U M P SEL ECT IO N :

(23)

M u lt ip le P um p s

If you have large or variable pumping requirements, consider installing multiple pumps rather than a single large pump. Multiple pumps allow you to shut down units under reduced-demand conditions, allowing the on-line units to operate at or near peak efficiency. If you have only a large, single pump, under similar conditions your only options are to throttle the pump or vary the speed. Consequently, your pump could operate at

reduced efficiency.

Additionally, you can service or repair multiple units during low demand periods to avoid total system shut-downs. Often two small pumps have lower NPSHR characteristics than one large pump. When you shop for multiple pump systems, it usually is important to choose pumps with a curve shape that continually rises as the flow reduces. When you operate pumps in parallel and series, contact the pump manufacturer to ensure

warrantability of the equipment for your specific application.

P U M P S IN PA RA L LEL

More than one unit pumping into a common discharge manifold (increases capacity, maintains head). Suction Suction Common discharge FLOW IN PARALLEL TDH (FT.) F L O W G . P . M . 190 180 170 160 140 120 100 90 200 700 1010 1200 1360 660 760 200 540 880 970 1050 860 1460 200 540 1890 2170 2410 1080 4RB 40-4 12.5" 5WB 40-2 7" TOTAL IN PARALLEL GPM PUMPS IN PARALLEL 200 160 120 TDH 80 40 0 400 800 1200 1600 2000 2400 5WB 4RB INCREASED FLOW

NOTE:The diagram on this page is intended

to show the parallel concept. It is not intended to show proper system design (no valves) or installation of parallel operation.

(24)

PUM PS IN SERIES

The discharge of the first stage is piped into the suction of the second stage (maintains flow, increases head).

HEAD IN SERIES T D H ( F T . ) 1200 120 400 168 186 354 600 163 175 338 0 171 192 363 200 170 190 360 800 155 154 309 1000 141 113 254 G.P.M. 4RB 40-4 12.5" 5WB 40-2 7" TOTAL IN SERIES GPM INCREASED HEAD PUMPS IN SERIES 400 300 TDH 200 100 0 200 400 600 800 1000 1200 5WB 4RB

NOTE:The diagram above is intended to show

the series concept. It is not intended to show proper system design (no valves) or installation of series operation.

(25)

Specific Speed

(NS) The speed at which an impeller would run if it were proportionally reduced in size so as to deliver 1 GPM against a total dynamic head of 1ft.

Specific Speedis a characteristic number which has a great deal of meaning to a pump designer. The intent of this description, however, is not to delve into any theoretical discussion, but to give us exposure to the concept, define what specific speed is, and show how it can have a practical meaning to us in our day to day work with pumps. Specific speed is best defined by its formula:

where: n = Re vo lu t io n s p e r m in u t e Q = B .E. P. Ca p a c it y in G P M a t

Maximum Impeller Diameter H = He a d i n f e e t a t B . E. P. ca p a c it y

Note that the chart below shows us various configurations of impellers used for pumps, ranging from those radial type impellers for centrifugal pumps through mixed flow and axial flow propeller type pumps.

Note also that specific speeds ranging from 500 to 4,000 refer to radial flow type impellers; specific speeds from approximately 4,000 to 10,000 refer to mixed flow type impellers and specific speeds above 10,000 are usually axial flow type impellers. Generally, you can predict the possible efficiency of a pump if you know its capacity at B E.P. and the specific speed.

Suction Specific Speed (S)is a parameter, or index of hydraulic design but here it is essentially an index descriptive of the suction capabilities and characteristics of a given first stage impeller. * It is expressed as:

where: RPM = p um p sp e ed

G P M = d e si g n ca p a ci t y a t b e st e f f i ci e ncy point for single suction first stage impellers (a t ma x. dia.)

NPSHR = net positive suction hea d required in feet (a t b est eff iciency point s)

*Note:Suction specific speeds can range between 3,000 and 20,000 depending on impeller design, speed, capacity, nature of liquid, conditions of service and degree of cavitation.

Cameron Hydraulic Data Indicates:A high

suction specific speed may indicate the impeller eye is somewhat larger than normal and consequently the efficiency may be compromised to obtain a low NPSHR. Higher values of S may also require special designs and may operate with some degree of cavitation. To avoid marginal designs on the suction side it is desirable for the user or systems engineer to consult with the Pump Manufacturer for suggested design, criteria, and to make certain that the suction conditions finally established will meet the requirements of the pump selected.

NS =

H 3/4

n Q

S=

(NPSHR) 3/4

RPM G PM APPROXIMATE SPECIFIC SPEED TO IMPELLER SHAPE

RADIAL FRANCIS MIXED

FLOW AXIAL G.P.M. NS= R.P.M. H 3/4 500 1000 2000 3000 4000 5000 10,000 15,000 CENTRIFUGAL MIXED FLOW PROPELLER

(26)

A ffinity Laws

The affinity laws express the mathematical

relationship between the several variables involved in pump performance. They apply to all types of centrifugal and axial flow pumps. They are as follows:

1. With impeller diameter held constant:

Q = Ca p a cit y, G PM H = To t a l He a d , Fe e t B HP = B ra k e Ho rse p o w e r

N = P um p Sp e ed , RP M

2. With speed, N, held constant. Using diameter change rather than speed change in the affinity laws is accurate only for small percentages of cutdown, usually 15% or less.

A FFIN IT Y REL A T IO N SH IP EX A M P LE

Cornell Model 6RB 13.5” diameter impeller reference speed – 1780 RPM.

Proposed operational speed – 2200 RPM.

Speed ratio: Affinity laws: Q1 x 1.236 = Q2 H1 X (1.236)2 = H2 BHP1 X (1.236)3 = BHP2 REFERENCE POINT ON 1780 RPM PERFORMANCE CURVE: 3000 GPM @150’ TDH @89% EFF. @14’ NPSHR PERFORMANCE AT 2200 RPM: Q2 = Q1 x 1.236 = 3000 GPM x 1.236 = 3708 GPM H2 = H1 x (1.236)2 = 150 TDH x 1.53 = 230 TDH BHP2 = BHP1 x (1.236)3 = 127.7 HP x 1.89 = 241 HP

*_{Note: NPSHR2 ~ 22’. NPSHR does not change}

exactly as the square of the speed ratio, but this is conservative for speed increases. If speed is being reduced, use the first power of the speed ratio. Refer to factory.

Note:Actual operating conditions depend on the system requirements. A. _Q1 Q2 N1 N2 = B. _H1 H2 = N1 N2

( )

2 C. _BHP1 BHP2 = N1 N2

( )

3 D. _NPSHR1 NPSHR2 = N1 N2

( )

2* A. _Q1 Q2 D1 D2 = B. _H1 H2 = D1 D2

( )

2 C. _BHP1 BHP2 = D1 D2

( )

3 2200 RPM 1780 RPM = 1.236 3000 G P M x 150' TD H 3960 x .89 EFF. = 127.7 HP HP1 =

(27)

Pump Engine Selection

300 0 GPM @ 155 ’ TDH

CORNELL MODEL 6RB

SPEED RANGE 1800 – 220 0 RPM 89% PU MP EFFICIENCY

BRAKE HORSEPOWER REQUIRED:

PERFORMANCE CURVE BASED ON: 500’ Elevation

29.38” HG 85° F

ACTUAL PUMPING ENVIRONMENT: 2500’ Elevation

30% Relative Humidity 115° F

TOTAL HORSEPOWER REQUIRED:

Pump Requirement 132.0 HP Service Factor – 10% 13.2 Temp./Humidity Correction – 3% 4.0 Elevation Correction – 6% 7.9

TOTAL NET CONTINUOUS HP

REQUIRED 163.7 HP

3000 G P M x 155' TD H 3960 x . 89

= 132 HP

(28)

Engine Derate Guidelines

1. For every 10° F above rated temperature, derate engine performance 1%.

2. For every 1000 FT above rated altitude, derate engine performance 3% for naturally aspirated four-cycle diesel engines and 1% for turbo charged four-cycle diesel engines.

3. Fan/Flywheel losses – 5-6%.

4. Service factor – 10% (allows for engine wear).

10” Stromag torque limitations – 362 FT-LBS.

DIESEL FUEL: WT. 7.1 LBS/GAL GASOLINE: WT. 5.9 LBS/GAL

TORQU E (FT-LBS) = 5250 x HORSEPOWER

RPM

ENGINE RPM ENGINE SPEED - RPM

3306T PERFORMANCE CURVES 950 684 T O R Q U E L B – F T B S F C L B / B H P - H B H P G / K W / H K W N - M C A B 100 RATING CURVES FUEL CONSUMPTION 120 140 160 180 200 850 750 260 220 1400 1600 1800 2000 2200 0.45 0.40 0.35 280 260 240 220 200 180 160 140 700 650 600 550 MODEL 685T H O R S E P O W E R T O R Q U E ( F T . L B S ) 400 1 2 3 1 2 3 365 375 380 600 550 500 450 230 210 190 170 150 130 110 1600 1800 2000 2200 1400 B.S.F.C. (LB/BHP-HR)

(29)

A verage Electric M o to r Life

HP RANGE AVERAGE LIFE LIFE RANGE

(YR) (YR) Lessthan1 12.9 10- 15 1- 5 17.1 13- 19 5.1- 20 19.4 16- 20 21- 50 21.8 18- 26 51- 125 28.5 24- 33 Greater than125 29.3 25- 38

The average of all units = 13.27 yr

Source: DOE Report DOE/CS-0147, 1980.

CAUSE OF FAILURE TOTAL FAILURE

(%)

Overload(overheating) 27

Normal insulation deterioration (old age) 5

Singlephasing 10

Bearingfailures 12

Contamination

Moisture 17

Oil and grease 20

Chemical 1

Chipsanddust 5

TOTAL 97

Miscellaneous 3

*Based on the study of 4000 failures over several years.

The major factor in the electric motor life is the life of the insulation system.

(30)

G uid e to O p tim um Electric M o tor Life

1. Supply Voltage:

A. Should not be beyond + or - 10% of the nameplate rating with rated frequency AND IN BALANCE.

B. Voltages should be evenly balanced as close to the reading on the (usually available) commercial volt meter. For continued operation, any voltage unbalance should not exceed 1%.

To illustrate the severity of this condition: a 3.5% voltage unbalance will result

in approximately a 25% temperature increase. Other side effects will be poor efficiency, increased noise and vibration.

2. Ambient Temperature:

A. Protect motor from direct sunlight. B. Provide cooling.

C. Derate service factors for elevati ons above sea level are as follows:

UP TO 3300 FT 1.15 SF 6000 FT 1.10 SF 10000 FT 1.00 SF

3. Overloading:

A. Select your motor carefully to match the load without using a service factor.

WATCH THE RUNOUT.

B. Provide dependable motor starting equipment to protect motor from lightening, single phasing and short cycling. Use the proper overload heater protection.

4. Ventilation:

A. Keep screens clean and free from foreign matter.

B. If shelter is provided, insure proper ventilation.

5. Lubrication:

A. Grease bearings properly as per manufactures instructions. B. Use the proper grease.

6. Location:

A. Protect motor from contamination (moisture, dirt, etc).

EX T EN D IN G T H E L IFE O F T H E IN SU L A T IO N SY ST EM

(31)

Electric Motor Comparisons

U N IT EN ERG Y SA V IN G IN D O L LA RS PER H O RSEP O W ER*

Hi gher Efficiency Lower Efficiency 72 74 76 78 80 82 84 85 86 87 88 89 70 0.296 0.576 0.841 1.093 1.332 72 0.280 0.545 0.797 1.036 1.264 74 0.265 0.517 0.756 0.984 1.200 76 0.252 0.491 0.718 0.935 78 0.239 0.467 0.683 0.788 80 0.227 0.444 0.549 0.65 0.750 82 0.217 0.321 0.423 0.523 0.620 0.716 Hi gher Efficiency 85 86 87 88 89 90 91 92 93 94 94.5 95 84 0.704 0.207 0.306 0.404 0.499 0.592 0.683 0.772 85 0.102 0.202 0.299 0.394 0.488 0.579 0.700 0.755 86 0.100 0.197 0.292 0.385 0.477 0.566 0.653 0.738 87 0.197 0.193 0.286 0.377 0.466 0.553 0.639 88 0.095 0.188 0.279 0.369 0.456 0.541 0.585 0.625 89 0.093 0.184 0.273 0.361 0.446 0.488 0.529 90 0.091 0.180 0.267 0.353 0.395 0.436 Hi gher Efficiency 91 91.5 92 92.5 93 93.5 94 94.5 95 95.5 96 96.5 90.5 0.045 0.090 0.134 0.178 0.222 0.264 0.307 0.349 91.0 0.045 0.089 0.133 0.176 0.219 0.262 0.304 0.345 91.5 0.044 0.088 0.132 0.174 0.217 0.259 0.300 0.341 92.0 0.044 0.087 0.130 0.173 0.215 0.256 0.297 0.338 92.5 0.043 0.086 0.129 0.171 0.212 0.253 0.294 0.334 93.0 0.043 0.085 0.127 0.169 0.210 0.251 0.291 93.5 0.042 0.084 0.126 0.167 0.208 0.248

(32)

Electric Control Panel Data

Textilemachinery, and other driven loadsrequiring smooth, shockless starting. M O T O R REQUIREM ENTS DESCRIPTIO N O F O P E R A T I O N STARTING CHARACTERISTICS IN PERCENT O F N O R M A L A D V A N T A G E S LIMITATIONS auto-transformer tapsat: 80-65-50% Current 64 42 25% Torque 64 42 25% 100% 33% 33% 100% Linevoltage 60% 45% A P P R O X . P RI CE COMPARISON ( % O F TY PE A T) APPLICATIONS P A R T W IN D I N G STA RTER T YP E P W PRIMARY REA CTOR STARTER TYPE PR REACTOR STA RTER TY P E R STAR-DELTA STA RTER TYPE SD A U T O -TRAN SFORM ER STARTER TYPE A T Can beused with any standard squirrel cage motor. Can beused with any standard squirrel cage motor. Can beused with any standard squirrel cage motor. Requiresa special

motor with 6 leads brought out (Delta wound stator).

Requiresa special motor in which the stator windingsare divided into twoor moreequal parts with six leadsprovided. Also dual-voltage motors can beused on the lower range. Themotor is

connected to thel ine through the reduced voltage tapsof an auto transformer for the starti ng interval and then directly across thelinefor running condition.

Thismethod requires two main or line contactors to connect themotor windingi n delta connection for running. A third contactor is used to form thestar point on the starting step.

Likethestar-delta starter,thisstarter requiresno external equipment. One windi ng is connected to thelinefor starting. After a time interval thesecond or run contactor connectsthe other motor winding to thelinei n parallel with thefirst winding.

A high resistanceis connected in seri es with themotor on starti ng and after a time interval this resistanceisshort-circuited and motor is connected directly to theli ne.

Themotor is connected to the line through the reduced voltage tapsof a reactor for thestarting interval and then directly acrossthe linefor running condition. Variablewith tapesetting and load.

High torque efficiency. All thepower taken from the line, except for transformer losses, is transmitted to the motor.Starti ng current and torque are easily adjusted by changing auto-transformer taps. Closed circuit

transition.

Thestar-deltastarter providesl ow in-r ush current with high torqueefficiency, without theuseof any external equipment. Normally open circuit transiti on but closed transition can be achieved with the use of resistors

Part-windingstarting providesone-step acceleration at a reduced current. So that the second current in-rush is not objecti onable. Closed circuit transiti on.

Thistypeprovides almost assmooth starting ast he reactor type starter. Thecurrent becomeslower and thevoltageat the motor terminals risesasthemotor accelerates.Closed circuit transiti on.

Thistypeprovides thesmoothest starting of all reduced voltage starting methods. Moresuitablefor joggingor inching service. Closed circuit transiti on.

Torque remains practically constant for thefir st step and practically consistent at another value for the second step.

Starting characteri stics depend on motor design and cannot be adjusted. Requires special delta wound motor.

Requiresspecial motor or dual-voltage motor on low range. Torqueefficiency is usually poor for high speed motors.

Unavoidablepower lossi n resistor. Low torque effi ciency. Duty cycle limi ted by thermal capacity of resistor. Tapsmust be selected on job site to obtain starti ng voltage level suitable for theload. Applicationswhere therearelimitations on starting voltage and current. Most widely used.

Low starti ng torqueapplications. Commercial air conditioning equipment. Geared or belted drives, and other delicate applications. 80 65% 80 65% 64 42%

(33)

1. 45 Bends (together to make Long Radius 90° Ell)

2. 90° Elbow w/ Mitered Bends

3. Suction Spool

4. Air Separator & Float Box 5. Hosing 7. Run-Dry (Optional) 8. Vacuum Pump 9. Belt Drive 10. Isolation Valve 11. Pipeline Support 11 1 11 4 DIA. MIN. 11 4" TO 6" 2 6 10 3 4 5 8 7 9

Dry Prim e M ethod s

SELECTRIC VACUUM PRIME CONTROL PANEL (VP-S UNIT) AUTO PRIMING SENSOR HOSE _VALVE ENCLOSURE (OPTIONAL) VACUUM PUMP

1. Bell Suction (if required) w/ Screen 2. 45 Bends (together to make

Long Radius 90° Ell)

3. Same as #2

4. Eccentric "Suction" Reducer 5. Concentric Increaser 6. 90° Elbow w/ Mitered Bends

7. Check Valve 8. Isolation Valve 9. Concentric Increaser

10. Vacuum Priming Chamber (VPS) 11. Pressure Gage & Isolation Cock 12. Pipeline Support 1 12 2 3 12 10 12 4" TO 6" 4 5 6 11 ₇ ₈ ₉ 11 4 DIA. MIN. KEY KEY

TYPICAL

A U T O

VACUUM

PRIME

CO RNELL

REDI-PRIME

®

WITH RUN-DRY

™

O P T I O N

(34)

Materials of Construction

CLEA R LIQ UID PUM P S SERIES W, Y , R A N D H

Volute Casing Wear Rings Impeller Impeller Washer Impeller Key Impeller Screw Suction Cover or Backplate Bracket, Frame Shaft Shaft Sleeve Seal Gland Packing Gland Packing Studs Packing Lantern Ring Packing Washer Fasteners

Product Flush Line Balance Line Anti-Cavitation Line Parts Standard Material of Construction Cast Iron

Bronze Fitted All Iron

Standard Hot Oil Construction High Pressure Abrasion Resistant Stainless

Steel Steel Bronze

**

Frame shaftsareSP; Close-coupled shaftsareSA Consult Factory

M A TERI A L CO D ES

SM SAEGrade5 SP StressProof Equal MOD.SAE1144 SS StainlessSteel AISI 416 ST StainlessSteel AISI 416 H.T.to300-325BHN SY Annealed304/316 StainlessSteel Tubing TE Glass-filledTeflon Z K Zamak-3orequivalent KS Keystock AISI C1018 BA Bronze(SAE660) ASTM B144-3BC93200 BP Copper Tubing BZ Bronze(SAE40) ASTMB584C83600 CA DuctileIron NodularNI-QT H.T.to400-500BHN Cl CastIron ASTMA48,Class30 CP DuctileIron ASTM A536-72 NOD-1B PK GraphitedAcrylic SA Steel AISI 1045 SB AnnealedSteel Tubing SC CastSteel AISI 1030,ASTMA216 SD StainlessSteel AISI 302,303,304 SE StainlessSteel

AISI 316,ASTM A296-CF8M SG StainlessSteel H.T.to400-500BHN

**

C I BA SS SS SS BA BZ BA C I SG C I C I C I C I SD PK TE BA SM BP SB SD PK TE SS SM SB SB SM SB SD TE BA SM BP SB SD TE SS SM SB SD SE TE SE SY SD TE SS SE SB SD TE BA SE SY C I BA BZ ST ST KS KS SD CP CP BA BZ ST KS SD CA CA SG CA ST KS SD SC SC C I SC SS SA SD BZ B A / B Z BA BZ SE SD SE SE SD SD ST KS SD C I C I C I C I C I C I C I C I C I C I o r Z K C I / S S VF Motor Stand Base Elbow

Base Elbow Stand Fab. steelor CI

C I Pr imer Red O xi de