pump theory.pptx

7/28/2019 PUMP THEORY.pptx

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FLOW

0 Flow describes the volume of liquid in a given period

of time.

0 Size of pump determines the flow.

0 Flow is a issue to select a pump.

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HEAD0 Basically, it indicates how high a given pressure can

lift a column of liquid. Meters of water column.0 Must be taken into account for sizing a pump:

0 Relation between flow and head.

0 Conversion between head and pressure

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PRESSURE0 Head: Universal measurement of pump performance,

independent of the liquid.

0 Pressure: Defined as a adapted measurement of pump

performance, dependent of the actual liquid and

application.

0 Important to Know:

0 Relation between head and pressure to select thr right

pump from datasheets and pump curves.

0 Will enable you to carry out basic sizing of pump for a

specific application.


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DENSITY0

The Density expresses how heavy a liquid, gas or solidis.

0 The pump inlet is affected by the pumping of liquids

with different densities.

0

To higher density, higher input powerNote: To select the pump must know the density of

the liquid


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EXAMPLE THE DENSITY OF

LIQUIDS


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Facts about density

0 Equal volumes of different substances vary

considerably in mass

0

we refer to the lightness or heaviness of differentmaterials by the use of the word density, symbolised

by (rho)

Density=mass/volume(Kg/m3)


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Power needed


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VISCOSITY

0 Viscosity is the opposition of a fluid to shear strains. A

fluid that has no viscosity is called ideal fluid.

0

The viscosity is manifested only in moving fluids.0 The viscosity the choice of the pump type and the

motor size


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Facts about viscosity

0 The viscosity of a liquied is independent of

pressure(excepts at very high pressures)

0

Viscosity tends to drop as temperature increases0 Centrifugal pumps can only handle liquids up to a

certain viscosity. At viscosities above this limit ,

positive displacement pumps must be used instead


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Power consumption

0 The power is used for the calculation of efficiency,

pump size and motor size.

0

P1The power input from the mains0 P2 The power input to the pump or the power output

from the motor

0 PHyd Hydraulic power


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Efficiency of the motor


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CAVITACION

0 Cavitation is a very common phenomenon, but is the leastunderstood of all pumping problems. defined as the rattlingnoise or rattle occurs in one pump or "skating" because thepressure of the pump decreases and the flow becomes erratic.When cavitation occurs, the pump not only fails in its basicservice to pump a liquid but also experienced internal damage,faulty seals, bearings, etc..In short, produces lacavitacin production losses, equipmentdamage and worst of all, injury to personnel.


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PUMPS AND OPERATION

PUMPS0 It argues that several pumps are operating in parallel,

when their flow goes to a common line, joining des for

greater load. As the pressure in the cargo is a single

common pipe, each pump functioning to adjust said

load


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0 Ability or quantity of fluid discharged in unit time.

0 Increasing pressure commonly designated by the term ofload (which is the energy provided to the fluid per unit

mass, is obtained by dividing the pressure increase by thespecific gravity of the fluid).

0 Power is the power consumed by the machine in the unittime.

0 The yield is assigned to the fluid power, divided by the total

energy absorbed by the machine.

pump theory.pptx

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