UNDERSTANDING PUMP.ppt

KIRLOSKAR BROTHERS LIMITED,KIRLOSKAR BROTHERS LIMITED,

DEWASDEWAS

UNDERSTNADING PUMP

KIRLOSKAR BROTHERS LIMITED, DEWAS

PUMP

Pump is a machine, which imparts energy to the liquid flowing through it.

This energy can be utilized EITHER to lift water from a lower level to higher level OR to circulate in a closed circuit.


PUMP


CLASSIFICATION OF PUMP






PUMP

A centrifugal pump converts energy of a prime mover (a electric motor or engine ) first into velocity or kinetic energy and then into pressure energy of a fluid being pumped.

The energy changes occur by two main parts of the pump, the impeller and the volute or diffuser.

The impeller is the rotating part that converts driver energy into the kinetic energy.

The volute or diffuser is the stationary part that converts the kinetic energy into pressure energy.


The energy created by the centrifugal force is kinetic energy. The amount of energy given to the liquid is proportional to the velocity at the vane tip of the impeller. The faster the impeller revolves or the bigger the impeller is, then the higher will be the velocity of the liquid at the vane tip and the greater the energy imparted to the liquid.

PRINCIPLE OF OPERATION


This kinetic energy of a liquid coming out of an impeller is harnessed by creating a resistance to the flow. The first resistance is created by the pump volute (casing) that catches the liquid and slows it down. In the discharge nozzle, the liquid further decelerates and its velocity is converted to pressure according to Bernoulli’s principle.

Therefore, the head (pressure in terms of height of liquid) developed is approximately equal to the velocity energy at the periphery of the impeller.



The liquid is filled in the pump casing and suction pipe. This process is called “Priming”.

When the impeller rotates, it spins the liquid filled between the vanes outward due to centrifugal action.

As liquid leaves the eye of the impeller, a low-pressure area ( vacuum ) is created at the eye of impeller.

This creates Differential Pressure between water source and impeller eye, causing liquid to flow toward the inlet.





PUMP TERMINOLOGY

Pumping system efficiency = Pump eff. x Motor eff. x Piping eff. x Foot valve eff.


PUMP TERMINOLOGY

Static Suction Lift (hss) : It is the vertical distance from liquid level to pump centre line. It exists when the source of liquid is below the pump centre line and attracts a negative sign.

Static Suction Head (hss) : It is the vertical distance from liquid level to pump centre line. It exists when the source of liquid is above the pump centre line and attracts a positive sign.

Static Delivery Head (hsd) : It is the vertical distance from pump centre line to the highest discharge point.


PUMP TERMINOLOGY

Total Static Head (hst) : It is the vertical distance from liquid level to the highest discharge point. It is an algebraic subtraction of static suction lift / head from static delivery head.

Pump with suction lift : Total Static Head = hsd – ( -hss)

hsd + hss

Pump with suction head : Total Static Head = hsd - hss

Total Head (H) : It is the sum of total static head and frictional head ( required to overcome the resistance to flow in the pipe and fittings ).

Total Suction Lift (Manometric Lift) Hm : It is the sum of total static suction lift and frictional head in suction branch.


PUMP TERMINOLOGY

STATIC DELIVERY HEAD TOTAL

STATIC HEAD

TOTAL HEAD = TOTAL STATIC HEAD + FRICTIONAL LOSSES IN SUCTION AND DELIVERY PIPE

STATIC SUCTION LIFT

STATIC DELIVERY HEAD


PUMP TERMINOLOGY

SUCTION LIFT SUCTION HEAD


Understanding Pressure


Understanding Pressure


CCHARACTERISTICHARACTERISTIC C CURVEURVE


CCHARACTERISTICHARACTERISTIC C CURVEURVE


HHEADEAD VsVs D DISCHARGEISCHARGE

FLAT CURVEFLAT CURVE relatively rapid increase in discharge relatively rapid increase in discharge

with reducing head.with reducing head. STEEP CURVESTEEP CURVE relatively rapid increase decline in relatively rapid increase decline in

head with increasing discharge.head with increasing discharge. STABLE CURVE (STABLE CURVE (DESIRABLEDESIRABLE) ) one discharge corresponding to any one discharge corresponding to any

specified head.specified head. UNSTABLE CURVEUNSTABLE CURVE two discharge corresponding to a two discharge corresponding to a

specified head.specified head. DROOPING CURVEDROOPING CURVE relatively sudden drop in head at relatively sudden drop in head at

particular discharge.particular discharge.


PPOWEROWER VsVs D DISCHARGEISCHARGE

NON-OVERLOADING CURVE NON-OVERLOADING CURVE 11 curve rises to a point and then falls as the discharge increases.curve rises to a point and then falls as the discharge increases.

OVERLOADING CURVE OVERLOADING CURVE 22 power increases continuously with the increase in discharge.power increases continuously with the increase in discharge.

1

2


EEFFICIENCY FFICIENCY VsVs D DISCHARGEISCHARGE

Efficiency curve rises to a peak value and then again Efficiency curve rises to a peak value and then again falls with increase in discharge.falls with increase in discharge.

BEP


Types of impeller profileTypes of impeller profile Radial flow : Liquid enters the impeller at

the hub and discharging radially.

Francis vane : Radial flow impellers with double curvature of the vanes at the inlet.

Mixed flow : Liquid enters axially and discharging in an axial and radial direction.

Axial flow : Liquid enters axially and discharging nearly axially.


Types of impeller Types of impeller Closed Impeller : A closed impeller has

vanes between two shrouds. These impellers are used for clear water.

Semi Open Impeller : A semi open impeller has exposed vanes, but with a support plate or shroud on one side. These impellers are generally used for liquids with small percentage of solids.

Open Impellers : Mostly open impellers are used in axial flow pumps. These impellers move lot of volume but not lot of head or pressure.


SPECIFIC SPEED


SPECIFIC SPEED

By definition, Specific speed (Ns) is revolution per minute at which a geometrically similar pump would run to deliver ONE GPM discharge at a head of ONE foot. It is a dimensionless index, which determine the profile of the impeller and performance of the pump.

Where,

N - Speed, rpm

Q - Discharge at BEP, US GPM

H - Head per stage at BEP, feet


SPECIFIC SPEED


Comparison of impeller profileComparison of impeller profile



Maximum attainable efficiencyMaximum attainable efficiency


EFFICIENCY


EFFICIENCY

Energy input = Energy useful + Losses

Efficiency = Energy useful / Energy input

Losses = Mechanical + Volumetric + Hydraulic ⇓ ⇓ ⇓

bearings leakage friction coupling (slip) entrance /

exit rubbing vortices separation disc friction


Losses in PumpsLosses in Pumps


The ENTRY LOSS caused by the liquid streamlining past the vanes’ edge into the impeller. This loss has a direct bearing on the capability of the impeller to suck the specified amount of liquid. Loss can be kept low by correct vane shape and finish.

LEAKAGE LOSS across a pressure differential, usually at the wear rings. This loss can be minimized by running the pump with close – but not dangerously close – clearance.





Rec

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ded

R

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mm

end

ed

Wea

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g R

ing

W

eari

ng

Rin

g

Cle

aran

ceC

lear

ance



DISC FRICTION is caused by the impeller shrouds rotating in liquid. The loss can be kept low by providing a good machining or casting finish to the impeller walls. Reducing the volume of liquid between impeller and volute walls is also an advantage.

The HYDRAULIC LOSSES in the pump are caused by friction and turbulence in all passages. Losses can be kept low by smooth finish, correct velocity and distribution of flow.



STUFFING BOX LOSSES must be kept low : By cutting out all unnecessary turns of packing By running the gland just right enough for a

satisfactory seal with adequate lubrication of packing and,

In case of mechanical seal, by ensuring that no undue friction horse power is consumed due to unsuitable rubbing faces or too high face loading.

Conventional means should be used to ensure low MECHANICAL LOSSES in bearings and other rotating components.







POWER CONNSUMPTION

Motor input (IPkW) : The electrical input to the motor.

Pump input (BPkW) : The power delivered to the pump shaft by the primemover through pump coupling or through direct shaft.

Pump output (LPkW) : The power delivered by the pump in the form of discharge at a given head.

Motor Input

Pump Input

Pump Output


EFFICIENCY

Pump EfficiencyPump Efficiency

pp = = Liquid PowerLiquid Power == H x Q H x Q

Pump InputPump Input 102 x BP102 x BP Motor EfficiencyMotor Efficiency

mm = = Motor OutputMotor Output == BPkWBPkW

Motor InputMotor Input IPkWIPkW Overall EfficiencyOverall Efficiency

oo = = Liquid PowerLiquid Power == H x QH x Q

Motor InputMotor Input 102 x IP 102 x IP


SUCTION LIFT


WHY SUCTION LIFT IS LIMITED ?

ATMOSPHERIC PRESSURE 10.33 mWC

VACUUM 0 mWC

IDEAL SUCTION LIFT = 10.33 - 0

= 10.33 mWC


PUMP TERMINOLOGY

NET POSITIVE SUCTION HEAD (NPSH)Related with the suction lift characteristic of the pump. It takes care of the atmospheric pressure at the site and the temperature of pumping liquid which affect the pump performance.

NET POSITIVE SUCTION HEAD AVAILABLE (NPSHA) : Related to pump installation.

NPSHA = Ha - Hvp - hss - hfswhere, Ha = atmospheric pressure in m

Hvp = vapour pressure of pumping liquid in mhss = static suction lift in mhfs = friction losses in suction branch including losses

in foot valve and bends in m


PUMP TERMINOLOGY

NET POSITIVE SUCTION HEAD REQUIRED (NPSHR)Related with pump design. It is the minimum energy required at the pump inlet to exhibit the rated performance as per the characteristic curve.

NPSHR = Ha - Hvp – Hman + Vs2/2gwhere, Ha = atmospheric pressure in m

Hvp = vapour pressure of pumping liquid in mHman = Manometric / Total suction lift in mVs2/2g = Suction velocity head m

At any Operating point NPSHA should be more than NPSHR

In the operating range if NPSHR > NPSHA, the pump will cavitate resulting in lower discharge and efficiency.


When the pressure of the liquid is reduced to equal to or less than its vapor pressure, the liquid begins to boil and small vapor bubbles or pockets begin to form. As these vapor bubbles move along the impeller vanes to a higher pressure area above the vapor pressure, they rapidly collapse.

Cavitation results in : Noise. Vibration. Pitting of impeller and Devlivery casing. Reduction in discharge and efficiency.

CAVITATION


EFFECT OF SUCTION LIFT


PARAMETERS

AFFECTING PUMP

PERFORMANCE


Pump Speed

Discharge varies directly in proportion to speed.Q N

Head varies in square proportion to speedH N2

Power varies in cube proportion to speed.P N3

Example :1500 1800

2000 3000Head (m) 16 23 28.4 64 Discharge (l/s) 16 19.2 21.3 32 Power (kW) 3.2 5.5 7.6 25.6Prime Mover (HP) 5.0 8.0 12.0 40.0


Impeller Diameter

Discharge varies directly in proportion to diameter.Q D

Head varies in square proportion to diameter.H D2

Power varies in cube proportion to diameter.P D3

Example : 200 210 220

230

Head (m) 16 17.6 19.4 21.2

Discharge (l/s) 16 16.8 17.6 18.4

Power (kW) 3.2 3.7 4.3 4.9

Prime Mover (HP) 5.0 6.0 8.0 8.0


Speed And Diameter


SYSTEM HEAD CURVESYSTEM HEAD CURVE

Effect of Speed and Impeller Dia.


Effect of Speed and Impeller Dia.

HE

AD

mP

OW

ER

kW

EF

FIC

IEN

CY

%

DISCHARGE l/s

Higher Speed / dia.

Lower Speed / dia.


Specific Gravity Pump develops Same Head (in meters of liquid) independent

of specific gravity but the pressure in kg/cm2 is proportional to the specific gravity.

Pump delivers the same quantity by volume independent of sg but the quantity by weight will be proportional to the sg.

Efficiency is un-effected by the sg. Power is directly proportional to sg. Permissible lift varies with specific gravity. As sg increases,

suction lift decreases. Example : Example : SG = 1 Power = 3.2 kW

SG = 1.1 Power = 3.5 kWSG = 0.9 Power = 2.9 kW


Other parameters

ALTITUDESuction lift values are given at atmospheric pressure at Mean Sea Level. Suction lift is reduced approx. by 1.2 m for 1000 m altitude.


Other parameters

HOT LIQUIDSHot liquid vaporizes at higher absolute pressure than cold liquids, therefore the suction lift must be reduced when handling hot liquids.


Other parameters

VISCOSITYAs viscosity increases Discharge Discharge decreasesdecreases Head Head decreases decreases PowerPower increases increases EfficiencyEfficiency decreases decreases


FRICTION LOSS IN

PIPING SYSTEM


FRICTION LOSSES IN PIPES

Friction Losses in Pipes is calculated by:

(1211 x 109) Q 1.852

Hf =

________________ ____

D 4.87 CWhere,Where,

hf = Friction losses in 100 m pipe length

d = Inside dia. of pipe in mm.

Q = discharge in l/s.

C = smoothness coefficient of pipe material.

150 for RPVC pipes.

140 for new G.I. Pipes.

120 for old G.I. Pipes.


FRICTION LOSSES IN PIPESMaterial C Material CAsbestos Cement 140 Glass 130Brass 130 - 140 Lead 130 - 140

Brick sewer 90 - 100Metal Pipes - Very to extremely smooth

130 - 140

Cast-Iron - new unlined (CIP) 130 Plastic 130 - 150Cast-Iron 10 years old 107 - 113 Polyethylene, PE, PEH 150Cast-Iron 20 years old 89 - 100 PVC, CPVC 150Cast-Iron 30 years old 75 - 90 Smooth Pipes 140Cast-Iron 40 years old 64-83 Steel new unlined 140 - 150Cast-Iron, asphalt coated 100 SteelCast-Iron, cement lined 140 Steel, welded and seamless 100

Cast-Iron, bituminous lined 140Steel, interior riveted, no projecting rivets

100

Cast-Iron, wrought plain 100 Steel, projecting girth rivets 100Concrete 100 - 140 Steel, vitrified, spiral-riveted 90 - 100Copper or Brass 130 - 140 Steel, corrugated 60Corrugated Metal 60 Tin 130Ductile Iron Pipe (DIP) 140 Vitrified Clays 110

Fiber 140Wooden or Masonry Pipe - Smooth

120

Fiber Glass Pipe - FRP 150 Wood Stave 110 - 120Galvanized iron 120


SR.

NO.

ORIGINAL

PIPE SIZE mm

REDUCED

PIPE SIZE mm

INCREASE IN

FRICTION LOSS %

01 30 25 375

02 40 30 200

03 50 40 314

04 65 50 354

05 80 65 220

06 100 80 360

Effect of pipe size

For a given discharge rate and pipe material


(hss + hsd)

(hfs + hfd)

DISCHARGE

HE

AD

SYSTEM HEAD CURVE

Effect of pipe size

65 X 65 MM

50 X 50 MM


FRICTION LOSSES IN PIPES - SOME FACTSFRICTION LOSSES IN PIPES - SOME FACTS

The longer the pipe, the greater the friction loss. The smaller the pipe diameter, the greater the friction

loss. The smoother the inner surface of pipe, the lesser the

friction loss. The fewer fittings and valves on the pipe line, the lesser

the friction loss. The lesser the no. of bends, the lesser the friction loss. Friction loss is not affected by the angular position of

the pipe. Friction loss is not affected by the pressure on the liquid

in the pipe.


SELECTION OF

PUMPING SYSTEM


SELECTION OF PUMPING SYSTEM

SYSTEM HEAD =

TOTAL STATIC HEAD(hss + hsd)

FRICTIONAL LOSSES (hfs + hfd)

VELOCITY HEAD(Vd2/2g)

+

+


Estimate Discharge Choose suitable pipe to limit friction losses

to 10% max. Choose suitable foot valve with ‘K’ factor less

than 0.8. Calculate total head. Choose the type of pumpset to be used

monobloc, coupleset etc. Select a suitable pump with maximum

efficiency at duty point i.e. matching of BEP with OP as well as Top flat efficiency curve operating point should fall in the best

efficiency zone for the busiest season i.e. RABI

ensuring that pump is suitable for summer season.

0

5

10

15

20

25

30

35

0 2 4 6 8 10

HE

AD

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 2 4 6 8 10

PO

WE

R

0

10

20

30

40

50

60

0 2 4 6 8 10

DISCHARGE l/s

EF

FIC

IEN

CY

Best Efficiency Point





SELECTION OF PUMPSETSELECTION OF PUMPSET

0

10

20

30

40

50

0 5 10 15 20H

ead

m

0

1

2

3

4

5

6

0 5 10 15 20

BP

kW

0

20

40

60

80

0 5 10 15 20

Discharge l/s

Pu

mp

Eff

icie

nc

y %


ESTIMATION OF DISCHARGE

Following factors are to be considered, while estimating the Discharge:

Yield of Water source Crops / Area to be irrigated Availability of electricity, which will decide the operating hours of

the pumpset Any restriction of the electricity board for prime mover rating

Q = A x I x 28 R x H

where,Q = Estimated Discharge in liters per secondA = Area of Crop to be irrigated (hectare or acre)I = Intensity of Irrigation for crop (cm or inch) (1 hectare-cm

= 1 acre-inch)R = Rotation period in daysH = Operating hours of pump in hours/day


H = ± hss + hsd + hfs + hffv + hfd + Vd2/2g

hss - Static Suction Lift / head m

hsd - Static Delivery Head m

hfs - Friction losses in suction pipe m

hffv - Friction losses in foot valve m

hfd - Friction losses in delivery pipe m

Vd2/2g - Velocity head m

CALCULATION OF TOTAL HEAD


Bernoulli’s Theorem






FRICTION LOSSES IN PIPES

Friction Losses in Pipes is calculated by:

(1211 x 109) Q 1.852

Hf =

________________ ____

D 4.87 CWhere,Where,

hf = Friction losses in 100 m pipe length

d = Inside dia. of pipe in mm.

Q = discharge in l/s.

C = smoothness coefficient of pipe material.

150 for RPVC pipes.

140 for new G.I. Pipes.

120 for old G.I. Pipes.


Pipe fittings


Pipe fittings


Friction losses in foot valve can be given by

hf = kXVs2/2g

where,

k = Friction factor (0.8 max)

Vs2/2g = Suction Velocity head m

FRICTION LOSSES IN FOOT VALVE


PERFORMANCE ADJUSTMENTPERFORMANCE ADJUSTMENT


ENERGY

EFFICIENCY IN

PUMPING SYSTEMS


PRESENT SCENARIOPRESENT SCENARIO Over 40% of the total energy is consumed by

electrical pumping systems alone. Over 15 million electric pumping systems are in

operation. Every year around 800,000 new pumpsets are

installed. Majority of the pumpsets (almost 80%) are

inefficient - are operating at as low as 50 to 70% of achievable efficiency.

Continued..


PRESENT SCENARIOPRESENT SCENARIO This low operating efficiency is a result of wrong selection This low operating efficiency is a result of wrong selection

of pumping systems :of pumping systems : Pumpsets are selected based on primemover rating and Pumpsets are selected based on primemover rating and

pipe size. No consideration to recommendation of pipe size. No consideration to recommendation of is:10804.is:10804.

Inefficient pumping systems are installed due to price Inefficient pumping systems are installed due to price advantage. advantage.

A lower hp efficient pumping system can do the job, A lower hp efficient pumping system can do the job, instead a higher hp inefficient system is often installed.instead a higher hp inefficient system is often installed.

In the event of hp based tariff and subsidy, derating is In the event of hp based tariff and subsidy, derating is common in agriculture sector.common in agriculture sector.

Obviously, there is huge potential to conserve both power Obviously, there is huge potential to conserve both power and energy.and energy.


REASONS FOR LOW EFFICIENCYREASONS FOR LOW EFFICIENCY

Initial cost

Energy cost

Maintenance cost

Seeing beyond visible


LIFE CYCLE COST



• Pump selection based on HP and pipe sizes or HP and No. of stages.

• Buying decision on the basis of PRICE alone.



FACTORS REASONS DESIRABLE

1. PUMP EFFICIENCY

2. SUCTION LIFT

3. SELECTION OF SYSTEM

4. ELECTRIC MOTOR

5. PIPES

6. MAINTENANCE

LOW AND STEEPEFFICIENCY CURVE

POOR

NON MATCHING WITH SITEAS WELL AS WELL.

INEFFICIENTOVER SIZED

UNDERSIZEDTO MANY BENDS

UNNECCESSARY LENGTHINFERIOR QUALITY OF PIPE

MATERIALIMPROPER OR NO MAINT.

REWINDING BY UNTRAINEDMECHANICS

HIGH PEAK AS WELL AS TOPFLAT EFFICIENCY CURVE

HIGH

AS PER IS:10804.

EFFICIENTMATCHING WITH PUMP

AS PER IS:10804AS MINIMUM AS POSSIBLEAS MINIMUM AS POSSIBLE

PIPE MATERIAL AS SMOOTHAS POSSIBLE

SCHEDULED MAINTENANCEREWINDING BY TRAINED

MECHANICS


ENERGYENERGY

ENERGYENERGY == kW x hkW x hwhere;where;

kW - Power consumption

h - Operating hour

Focus should be on reduction of Focus should be on reduction of kWkW instead instead of reduction of of reduction of hh to : to :

Conserve power as well as energy. To improve the voltage condition. Energize more no. of pumpsets from the same

transformer.


For a given flow rate (Q), reduced Head (H) For a given flow rate (Q), reduced Head (H) and higher efficiency of pump & and higher efficiency of pump & primemover will result in lower kW primemover will result in lower kW consumption.consumption.

kW =K x

H x Q

pump primemover

POWER CONSUMPTIONPOWER CONSUMPTION

x

Reduce friction losses

Use Efficient pump and motor


H = hst + hfpiping + hffootvalve + Vd2/2g

TOTAL HEADTOTAL HEAD

Reduction in friction losses in piping, foot valve Reduction in friction losses in piping, foot valve and equipment will result in reduced Head (H).and equipment will result in reduced Head (H).

hst + hfpiping + hfequip + Vd2/2g +(Hequip)H =

Agriculutral pumping

Industrial pumping


RECTIFICATION OF PIPINGS AND FOOT

VALVE


RECTIFICATION OF COMPLETE PUMPING

SYSTEM


EVALUATION OF RECTIFICATION EVALUATION OF RECTIFICATION MEASURESMEASURES

Sr. No. RECTIFICATION MEASURE ENERGY **CONSUMPTION

kWh

POWERCONSUMPTION

kW

1. REPLACEMENT OF SUCTIONPIPE AND FOOT VALVE

REDUCES INCREASES

2. REPLACEMENT OF SUCTIONAND DELIVERY PIPES AND FOOTVALVES

REDUCES INCREASES

3. REPLACEMENT OF PIPING, FOOTVALVE AND PUMP

REDUCES INCREASES

4. REPLACEMENT PF COMPLETEPUMPING SYSTEM INCLUDINGPIPING, FOOT VALVE ANDMONOBLOC PUMP.

REDUCES REDUCES

** FOR PUMPING SAME QUANTITY OF WATER


ACHIEVING ENERGY EFFICIENCY

To reduce the flow rate, do not throttle, but trim the impeller.


Use Variable Speed Drive to meet the fluctuating requirement.



Use multiple pumps in parallel operation, where flow rate requirement is varying.



Use multistage or multiple pumps in series in case of high ‘H’ / high pressure application.



INSTALLATION &

TROUBLE SHOOTING


Installation Location: The pump should be located near to the water source to

minimize the suction lift.

Grouting: After the installation is completed, the foundation bolts should be tightened evenly and grouting may be completed. Sufficient time should be allowed for setting and seasoning of the foundation.


Piping

Pipe size should be as per the flange size to get higher discharge.It is not recommended to reduce the pipe length.

The piping should be airtight. Any leakage in suction pipe may drastically affect the performance of the pump.

The piping should be as short as possible for getting better discharge.


Piping

The horizontal length of the suction pipe should be straight to avoid air trapping in pipe.

A check valve should be installed in the pipe line for delivery pressure more than 20 meters.


ELECTRICAL CONNECTIONS

Proper earthing connection should be made at the bolts provided for earthing.

Proper size cable should be used between supply and motor terminals to minimize voltage drop.

Nuts at terminal should be tightened properly. No. of joints in cable should be as minimum as possible,

preferably joints should be avoided. Wires and connections should be properly insulated. If

not, it may be lead to fatal shock. Proper backup protection (reputed makes starter, main

switch and fuse) should be used.


TROUBLE SHOOTING

Failure to deliver water Wrong direction of rotation Pump not primed or filled with liquid Air or vapor pocket in suction line Suction pipe insufficiently submerged NPSHA too low – suction lift too high Pump not upto rated speed Air leaks in suction line or stuffing box


TROUBLE SHOOTING

Pump does not deliver rated discharge Air or vapor pocket in suction line NPSHA too low – suction lift too high Power supply is not correct

Air leaks in suction line or stuffing box Foot valve too small Foot valve clogged Viscosity greater / lower than rated Wear rings worn Impeller damaged Speed different than specified


TROUBLE SHOOTING

Pump does not prime Pump and suction line not filled with liquid Air leaks in suction line or stuffing box Gas or vapor in liquid

Pump losses water after start Air or vapor pocket in suction line NPSHA too low – Suction lift too high Air leaks in suction line or stuffing box Gas or vapor in the liquid


TROUBLE SHOOTING

Pump does not deliver rated head Wrong direction of rotation NPSHA too low – suction lift too high Viscosity greater / lower than rated Wear rings worn Impeller damaged Speed different than specified Gas or vapor in the liquid


TROUBLE SHOOTING

Pump overloads prime mover Pump running beyond lower recommended head. Lower pump efficiency

Stuffing box overheats Gas or vapor in liquid Gland packing too tight Gland packing not lubricated Wrong grade of packing Insufficient cooling water


Degrees of Protection IPDegrees of Protection IPFIRST NUMBER : protection against the contact of external solid bodies and against the access to dangerous parts

numb. protection of the material protection of the persons 0 not protect

1 protected against solid bodies of superior dimensions to 50 mm.

protect against the access with the back of the hand

2 protected against solid bodies of superior dimensions to 12 mm.

protect against the access with a finger

3 protected against solid bodies of superior dimensions to 2.5 mm.

protect against the access with a tool

4 protected against solid bodies of

superior dimensions to 1 mm. protect against the access with a

wire

5 protect against the powder protect against the access with a

wire

6 totally protect against the powder protect against the access with a

wire


Degrees of Protection IPDegrees of Protection IP

SECOND NUMBER : protection against the penetration of the liquids

numb. protection of the material 0 not protect

1 protect against the vertical fall of water drops

2 protect against the fall of water drops with inclination max of 15°

3 protect against the rain

4 protect against the water sprays

5 protect against water jets

6 protect against big waves

7 protect against the effects of the immersion

8 protected against the effects of the submersion


Class of Insulation

Particulars ‘A’ Class ‘E’ Class ‘B’ Class ‘F’ Class

Temperature withstandingcapacity

105C 120C 130C 155C

Frame size Bigger Moderate Smaller Smallest

Weight of motor Very Heavy Heavy Moderate Light

Cost of motor Very high High Low High

Copper Used Very high High Moderate Low

Heat Dissipation Factor Poor Fair Good Excellent

Resistance to Flame Poor Fair Good Better

Effect of Moisture & Humidity Very high High Low Very low


THANK YOU


Centrifugal Force


Packing Selection

Documents

UNDERSTANDING PUMP.ppt