Pump Selection

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Pumps
Selection, Operation & Maintenance

Dr. M.F. Khalil

Professor Mech. Eng. Dept. Alexandria University
Alex.Eng.Society Short Course By MFKhalil 1

Pumps
Function Classification Construction, Theory , Operation & Applications Alex.Eng.Society Short Course By MFKhalil 2

Pump
Pump is a mechanical device which • converts mechanical energy of its driving unit ( electric motor, diesel engine, steam turbine ,gas turbine ,wind turbine.. Etc.) to hydraulic energy .This hydraulic energy increases the energy of the pumped liquid and enabled it to overcome the static head and hydraulic losses in piping in which the pump is interposed. Alex.Eng.Society Short Course By MFKhalil 3

Hst Hm Hss

Hmd

Hsd

Hms

Pump in piping system
Alex.Eng.Society Short Course By MFKhalil 4

•Total static head Hst = the vertical distance between the water surface level of the suction and discharge tanks. •Static discharge head Hsd = the vertical distance from the pump centerline up to The water surface level in the discharge tank. •Static suction head Hss (+ve) Applies when the supply tank is above the pump. It isThe vertical distance from the pump centerline up to the water surface level in the suction tank.. •Static suction lift Hss (-ve) Applies when the supply tank is below the pump. It is the vertical distance from the pump centerline down to the water surface level Alex.Eng.Society Short Course By MFKhalil 5

•Velocity head v2 /2g = the kinetic energy of liquid in pipe. • Head loss hls =The head needed to overcome the head loss due to pipe friction & fittings. •Manometric delivery head Hmd = static delivery head +head loss in delivery pipe. pipe •Manometric suction head Hms =the static suction head -the velocity head ( in The suction pipe) –head loss in the suction pipe. •Total Manometric head Hm = the difference between the Manometric delivery head and the Manometric suctionBy head. Alex.Eng.Society Short Course MFKhalil 6

Total Static Head:

Hst =Hsd−Hss

Manometric Suction Head ; v 2 H ms = H ss − hls − s 2g .Manometric Delivery Head ; .Manometric Delivery Head ; Total Manometric Head ;

H md = H sd + hld
H m = H md − H ms

Pump Hydraulic (output) Power;

Pi = wQH m
Pump shaft (Input) power;

Psh =

wQH m

Alex.Eng.Society Short Course By MFKhalil

η pump

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Total Manometric Head :
H m = H md − H ms vs2 H m = H st + hl + 2g v 2  fL  H m = H st +  d + ∑ C + 1 2g   Q= v..., 4 H m = H st + KQ2 .....Piping.System.Equation Alex.Eng.Society Short Course K = Pipeline.Const. = Function( f ByL, d , bends.....) , MFKhalil 8

πd 2

Alex.Eng.Society Short Course By MFKhalil

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Classification of pumps

Pumps
Positive displacement pumps Dynamic pressure or rotodynamic Axial Vane Gear Screw Mixed Centrifugal Air lift Others

Reciprocating Piston Plunger Diaphragm

Rotary

Jet or ejector

Alex.Eng.Society Short Course By MFKhalil

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Non Mech.Pumps:Jet pump ,Air Lift Pump...
Uses available pressurized fluid to lift another fluid. No mech. Parts=less operation & troubles but low operating efficiency.

Alex.Eng.Society Short Course By MFKhalil

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Jet Pump
Efficiency < 30%
Low Pressure Fluid

High Pressure Fluid

Alex.Eng.Society Short Course By MFKhalil

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Air Lift Pump. pump operates when:

wl Z > wm L
Alex.Eng.Society Short Course By MFKhalil

z L

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Positive Displacement Pump
Positive Displacement Pump has a cavity filled with liquid ,during ,during operation ,from the suction side and then displaced to the delivery side. delivery When the delivery side is closed the liquid is accumulated in pump cavity pump generating very high pressure ,this may cause pump.

Don’t Use delivery throttle valve for flow control.
Positive Displacement Pumps may be a rotary lobe, gear , piston, piston, diaphragm, screw, progressing cavity, Reciprocating piston pump,, etc. pump,,

Rotary Lobe Pump
Alex.Eng.Society Short Course By MFKhalil

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