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PUMP TECHNOLOGY TRAINING

- CENTRIFUGAL PUMP TECHNOLOGY- CLASSIFICATION OF PUMP- CENTRIFUGAL PUMP FUNCTION- HYDRAULID DESIGN- IMPELLER DESIGN - BASIC PUMP HYDRAULIC- INSTALLATION

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CENTRIFUGAL PUMP TECHNOLOGY

Pump definition

- Liquid higher pressure- Deliver liquid- Energy transfer device

Centrifugal Force

Kinetic Pump

Centrifugal force

Displacement Pump

Changed volume

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Kinetic Pump Positive Displacement Pump

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Delivery GasMachine that deliver liquids are simply called pump but if gas are involved three different term are in use

Fan Pressure rise very small

Blower Up to 1 atm

Compressor Above 1 atm

Extract Energy

Machine that extract energy from the fluid

Turbine

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CLASSIFICATION OF PUMPPumps maybe classified on the basis of the applications they serve, the material from which they are constructed, the liquid they handle, and even their orientation in space.

Application Material Pumping Medium

Orientation

A basic system of pump classification defines the principle by which energy is added to the fluid. This system is therefore related to the pump itself and is unrelated to any consideration external to the pump such as material or orientation of pump.

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A. Classification of kinetic pump B. Classification of displacement pump

Metering pump

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API STANDARDAPI is the only national trade association that represents all aspects of America ﾕ s oil and natural gas industry. 400 corporate members, from the largest major oil company to the smallest of independents, come from all segments of the industry. They are producers, refiners, suppliers, pipeline operators and marine transporters, as well as service and supply companies that support all segments of the industry.

API 610 Centrifugal Pumps for Petroleum Petrochemical and Natural Gas IndustriesTenth Edition October 2004

Advocacy Research and Statistic

Standard Certification Education

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API 610 Pump classification type identification

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Pump Type OH1

Foot-mounted single-stage overhung pumps

OH1 does not meet all the requirements of API 610

Pump Type OH2Centerline-mounted single-stage overhung pumps, single bearing housing

Pump Type VS4

Vertical suspended, single-casing volute line-shaft driven

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Hydraulic DesignThe most common type of centrifugal pump is volute style.

- Shape- Cross sectional area

A volute is a curved funnel increasing in area to the discharge port. It is often used with impeller pumps. As the area of the cross-section increases, the volute reduces the speed of the liquid and increases the pressure of the liquid.

Volute Centrifugal Pump

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Hydraulic Design

Diffuser style- increase efficiency- prevent excessive buildup of pressure

Pump diffuser bracket

Pump diffuser velocity profilePump diffuser 3D model

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Hydraulic DesignClassify centrifugal pump by impeller styles

-Fully open; The vanes extend radially from impeller hub with out a back shroud or front cover plate.- Semiopen; The vanes project forward from the back shroud, and there is no cover plate.- Fully closed; A full back shroud and full front cover plate enclose and support the vanes.

Fully Open Semiopen Fully Closed

Efficient

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Impeller Design/The cause of the pump curve

STEADILY RISING STEEP FLAT

UNSTABLE UNSTABLE (saddle-shape)

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Impeller Design/The cause of the pump curve

Best Efficiency Point (BEP)The Best Efficiency Point is the point H(Q)), where the pump operates at the maximum efficiency.

Characteristic curves of a centrifugal pump in dependence of the flow Q.

Usually the following curve are shown

Head H(Q)Power P(Q)Shaft power P2(Q)Power input P1(Q)Efficiency Hydraulic efficiency Total efficiencyNPSH(Q)Speed N(Q)

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Impeller Design/The cause of the pump curveCharacteristic of the impeller affect to the pump curve as the following1. Impeller widthChanging the widht of the impeller of a centrifugal pump willusually alter the head-capacity. 2. Number of VaneIncreasing the number of vanes in an impeller produces a flatter H-Q curve.3. Warp of vane

A higher-head, lower-flow impeller usually require more warp or sweepback.

Centrifugal Pump Function1.To raise a liquid from one level to another.2.To force a liquid into a vessel at a higher pressure by overcoming internal pressure.3.To force a liquid through a pipe by overcoming piping and fitting friction losses.

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Basic Pump Hydraulics

The first law of thermodynamics is the basis of all centrifugal pump.

The internal or mechanical energy of a system appears as kinetic, pressure, and potential energy; these are interchangeable and their sum must remain constant.

Head is a term that expresses the energy of a fluid due to its elevation above some reference point, its velocity, and its pressure.

- Static Head - Dynamic Head

P gh

= water density, 1000 kg/m3

g = the standard earth gravity, 9.81 m/s

h = depth of water column, m

C2/2g

C = fluid velocity, m/s

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Basic Pump Hydraulics

Static head Velocity or Dynamic head Static head

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Basic Pump HydraulicsContinuity equation

The mass flow of fluid per unit of time passing any point is constant

Q AVQ = fluid mass flow, m3/sA = pipe cross section area, m2V = fluid velocity, m/s

Energy conversion

1.Simple one-dimensional formula2.Computer simulation, CFD Technique

To construct an elementary theory of the pump performance,we assume one-dimensional flow and combine idealized fluid velocity vectors through the impeller with the angular momentum theorem for a control volume.

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Basic Pump HydraulicsApply angular momentum

T Q(r2vt 2 r1vt1)

Power delivered to the fluid is

PLA T

YLA PLAQ

Specific work

The useful specific work Y done by the pump is less than that done by the impeller because of the losses in the intake, impeller, and diffusor. These losses are expressed in terms of efficiency.

Specific work depend on Contour of the hydraulic components of the pump, delivery rate, peripheral velocity

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Basic Pump Hydraulics

Interrelationship between a pump and the pumping plant

Bernoulli Equation

Ps

Zs g

cs2

g Y

Pd

Zd g cd

2

Pump suction nozzle Pump

Energy input Energy output

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Basic Pump Hydraulics

Power, losses and efficiency

Total Efficiency

vnm

v

n

m

= volumetric efficiency

= hydraulic efficiency

= mechanical efficiency

Specific Speed

nq nQ

H34

The power input required by the pump

PQgH

n = speed rpm P = power, watt

Q = volume flow rate, m3/sH = head, m

For cold water

0.82

P = 12 QH (kW)

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Basic Pump HydraulicsTotal Head of The Pump

Differential Head; The differential head developed by a centrifugal pump is the measure of the total energy increase imparted to the liquid by the work done within the pump.

Total Head; the total head is the discharge head plus or minus the suction head

The head is a unit of energy and corresponds to the total head between the suction and delivery nozzles as define by Bernoulli. It is independent of the characteristics of the pumped medium, and for a given pump depends only on the flow rate and the peripheral speed of the impeller.

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THE TOTAL HEAD REQUIRED BY A PUMPING PLANT

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THE TOTAL HEAD REQUIRED BY A PUMPING PLANT

In order to examine total head required by the plant at design flow rate, it is necessary to consider the energy equation (Bernoulli equation). The flow energy of the pump is defined in all terms energy per unit mass of pumped fluid.

ps

Zs g

cs2

2 Y

pd

Zd g

cd2

2In pump design, it use term of unit weight under gravitational acceleration. It is know as the head H.

H Yg

Generally the pump draws from a reservoir whouse surface is at a pressure pe and delivers to a second reservoir at a pressure pa. The plant head requirement is then define as

HA pa pe

g Za Ze

ca2 ce

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2gHvs Hvd

Hvs = total head loss in the intake lineHvd= total head loss in the delivery line

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NET POSITIVE SUCTION HEAD

The total suction head HH is the different between total head (static head plus dynamic head) and the vapour pressure head in the pump intake.

HH pges pD

gIf the suction head is referred to the centerline of a horizontal pump then

NPSH psabs

pD

gcs2

2gThe NPSH value of the plant defines the total pressure at the pump suction nozzle for given fluid characteristics at a certain flow rate.

NPSHavail pe abs

pD

gZe Zs

ce2

2g Hvs

When the pump is operating in the suction mode, Ze is negative.To avoid cavitation

NPSHA > NPSHR

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SUCTION SPECIFIC SPEED

It is used to described geometrically similar impeller suction designs.

S n QNPSH 3

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Note

US unit n / rpm, Q / gpm, NPSH / ft•For cold water and general service applications, suction specific speeds of 8,500 and lower are selected.2. For boiler feed and condensate applications and for general hydrocarbon service, values of suction specific speed typically range between 9,000 and 12,000.3. For a double suction pump the flow is divided by 2 since there are 2 impeller eyes. 4. Multiply the value in SI unit by 0.8607 to receive US customary.

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INSTALLATION

-Temporary Alignment- Installing Foundation Bolt- Final Alignment- Grouting- Adjustment

Foundation and anchor bolts

- Anchor should be accurately set and firmly secured- Rechecked anchor bolt against the foundation drawing; length, diameter, thread length- Anchor bolt should be checked for proper projection- Put grease on the thread- Plastic or metal anchor bolt sleeves should be used