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PUMPS

NAME :SITI FATIMAH BINTI

NGAGIMAN

STUDENT ID : 2011683532

GROUP : EH 221 2B

PROGRAMME : FLUID MECHANICS

LECTURER’S NAME : MR RUSMI BIN ALIAS

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TABLES OF CONTENTS:

BIL TITTLE PAGES

1. What is pumps??

1.1 The importants and uses of the pumps.

1.2 The classification of pumps.

1.3 The examples of pumps.

1.4 The positive displacement and dynamic

comparison.

1.5 Positive displacement pump.

- Types of positive displacements

pump.

- The application of the positive

displacement.

Peristaltic pump

Plunger pump

Impulse pump

1.6 Dynamic pump

- Types of dynamic pump.

- The application of the dynamic

pumps.

Centrifugal pump

Axial flow pump

Mixed flow pump

2. The selection of the pumps.

2.1 The factors that involves on choosing

the pumps

2.2 Key parameter of peristaltic pump

3. NPSH

3.1 The definition of the NPSH.

3.2 How to increase the NPSH??

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4. References

WHAT IS PUMPS??

Based on your accounting, how many pumps do you have??? It

actually a very interesting question. If we asked the contractor or rental

store operator, they might be respond with the question with the number

between 1 until 30. On the other hand, a layperson might be said that they

reply that they do need of pump in their home or workplace.

But actually with a zero knowledge about the pumps, they are not

noticed that all the properties either at home, workplace or everywhere

are majority used a pumps. Pumps infact are among the most widely

manufactured items in the world and their many designs permit their use

in variety of applications. The pumps are very important mechanicals

devices in industry, agriculture and also daily live. They actually are used

in everything from washing machines, refrigerators, cars and trucks to

construction sites, waste water treatment facilities and food processing

plant.

A pump is a device used to move fluids which is liquids or gases or

sometimes slurries by mechanical action. By moving the fluid, pumps must

have a mechanism which oerates them, and consume energy to perform

the mechanical work. Pumps can be classified into two types which is

positive displacements and dynamic pumps. These two catogeries also

have any subcatogories of pumps. The figure below show the some types

of pump.

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Figure 1: A small, electrically power Figure 2: A large,

electrically driven

pump pump

THE IMPORTANTS AND USES OF THE PUMPS:

Based on the my information, the pump has two omportant

functions which is it has an ability to supply liquid at required rate of flow.

Besides, the pump also used as an impart energy to the liquid, thereby the

pressure is increasing.

Pumps are used for a variety of applications. Below are the few

application of the uses of the pumps which are:

1. Drainage - used to control the level of water in a protected

area.

2. Sewage - used in the collection and treatment of the

sewage.

3. Irrigation - used to make dry lands agriculturally productive.

4. Chemical industry - used to transport fluids to and form various

sites in the chemical plant.

5. Petroleum industry - used in the every phase of petroleum

production, transportation and refining.

6. Medical field - used to pump fluids in and out of the body.

7. Steel mills - used to transport cooling water.

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THE CLASSIFICATIONS OF PUMPS:

A pump is defined as a device that moves a liquid by increasing the

energy level of the liquid. This kind of devices is very vital and played a

main role in our daily live of applications. Note that the pumps are divided

into two distinct groups. One group pumps the liquids by means of positive

displacement and the other group pumps the liquids by means of

dynamics actions.

For the positive displacement pumps, it can be divided into two

kinds of catogeries which are reciprocating and rotary pumps. The

examples of pumps that involves in the reciprocating are power,

diaphragm, metering, direct acting pumps and etc. The rotary mostly

included screw and gear pumps. While the dynamic pumps also can

divided into two types of catogeries which are single stage and multistage.

There are many examples for the single stage dynamic pumps which are

overhug, inline, integral gear, centrifugal, double flow, sump, submersible

and also the magnetic drive. Compare with the multistage dynamic

pumps, the examples such are horizontal split, barrel, canned, sump and

submersible pump. All the examples that had stated above can be simplify

as figure below.

TYPES OF PUMPS

POSITIVE DISPLACEMENT DYNAMIC

RECIPROCATING ROTARY MULTISTAGE SINGLE STAGE

1. Power

2. Diaphragm

3. Metering

4. Direct acting

1. Screw

2. Gear

1. Overhug

2. Inline

3. Integral gear

4. Centrifugal

5. Double flow

6. Sump

7. Submersible

8. Magnetic

drive

1. Horizontal split

2. Barrel

3. Canned

4. Sump

5. Submersible

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Figure 3 : Types of pumps.

THE EXAMPLES OF PUMPS:

Figure 4 : screw gear Figure 5: reciprocating pump Figure 6: centrifugal pump

THE POSITIVE DISPLACEMENT AND DYNAMIC PUMPS

COMPARISON.

PROPERTIES POSITIVE DYNAMIC

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DISPLACEMENT

DEFINITION Increase pressure by

operating on a fixed

volume in a confined

space

Increase pressure by

using rotary blades to

increase fluid velocity

TYPES Screw, gear,

reciprocating

Centrifugal axial

CHARACTERISTICS 1. Constant volume

2. Variable differential

head

3. Relatively

insensitive to liquid

properties

4. Relatively

insensitive to

system changes

5. No self-timing

1. Variable volume

2. Constant

differential head

3. Sensitive to liquid

properties

4. Sensitive to

system changes

5. Self-timing

THE POSITIVE DISPLACEMENT PUMP:

Positive-displacement pumps are another category of pumps. Types

of positivedisplacement pumps are reciprocating and rotary pumps.

Positive-displacement pumps operate by forcing a fixed volume of fluid

from the inlet pressure section of the pump into the discharge zone of the

pump. These pumps generally tend to be larger than equal-capacity

dynamic pumps.

Positive-displacement pumps frequently are used in hydraulic

systems at pressures ranging up to 5000 psi. A principal advantage of

hydraulic power is the high power density (power per unit weight) that can

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be achieved. They also provide a fixed displacement per revolution and,

within mechanical limitations, infinite pressure to move fluids.

In the other words, positive-displacement pumps displace a known

quantity of liquid with each revolution of the pumping elements. This is

done by trapping liquid between the pumping elements and a stationary

casing. Pumping element designs include gears, lobes, rotary pistons,

vanes, and screws.

Positive Displacement pumps are found in a wide range of

applications -- chemical-processing; liquid delivery; marine; biotechnology;

pharmaceutical; as well as food, dairy, and beverage processing. Their

versatility and popularity is due in part to their relatively compact design,

high-viscosity performance, continuous flow regardless of differential

pressure, and ability to handle high differential pressure.

Figure 7 : A lobe pump

THE POSITIVE DISPLACEMENT TYPES:

A positive displacement pump can be futher classified according to

the mechanism used to move the fluid which had been mentioned above.

1. Rotary type positive displacement:

- Internal gear, screw, shuttle, block, flexible vane or sliding

vane, circumferential piston, helical twisted roots or liquid ring

vacuum pumps.

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Figure 8: rotary vane pump

Positive displacement rotary pumps move fluid have a rotating

mechanism that creates a vacuum that captures and draws in the liquid.

Advantages:

- Rotary pumps are very efficient[citation needed] because they

naturally remove air from the lines, eliminating the need to

bleed the air from the lines manually.

Drawbacks:

- Because of the nature of the pump, the clearance between the

rotating pump and the outer edge must be very close, requiring

that it rotate at a slow, steady speed. If rotary pumps are

operated at high speeds, the fluids will cause erosion,

eventually developing enlarged clearances through which liquid

can pass, reducing the efficiency of the pump.

2. Reciprocating type positive displacement:

- Piston or diapragm pumps.

Reciprocating pumps are those which cause the fluid to move using

one or more oscillating pistons, plungers or membranes (diaphragms), and

restrict motion of the fluid to the one desired direction by valves.

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The pumps can be powered manually, by air or steam, or by a belt

driven by an engine. This type of pump was used extensively in the early

days of steam propulsion (19th century) as boiler feed water pumps.

Reciprocating pumps are now typically used for pumping highly

viscous fluids including concrete and heavy oils, and special applications

demanding low flow rates against high resistance. Reciprocating hand

pumps were widely used for pumping water from wells; the common

bicycle pump and foot pumps for inflation use reciprocating action.

These positive displacement pumps have an expanding cavity on the

suction side and a decreasing cavity on the discharge side. Liquid flows

into the pumps as the cavity on the suction side expands and the liquid

flows out of the discharge as the cavity collapses. The volume is constant

given each cycle of operation.

Figure 9: simple hand pump, reciprocating positive displacement.

VARIOUS POSITIVE DISPLACEMENT PUMPS:

The positive displacement principles applies in the following types of

pumps:

1. Rotary lobe pump

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2. Progressive cavity pump

3. Rotary gear pump

4. Piston pump

5. Vane pump

6. Regenerative( peripheral) pump

7. Peristaltic pump

APPLICATION OF POSITIVE DISPLACEMENT:

1. PERISTALTIC PUMP

A peristaltic pump or known as roller pump is a type of positive

displacement(PD) pump which is used for pumping a variety of fluid either

liquids or gases. The fluid is contained within a flexible tube fitted inside a

circular pump casing. A rotor that used to compresses the flexible tube is

attached to the external circumference in the form of ‘rollers’. As the rotor

turns, the forces fluid is pumped to move to the tube because the part of

the tube that under compression is pinched closed.

Mostly this kind of process is used in the biological systems

such as gastroitestinal tract. It also used in heart-lung machines to

circulate blood during a bypass surgery as the pump does not cause

significant hemolysis.

Besides, the peristaltic pumps are also used in a wide variety

of industrial applications. Their unique design make them especially suited

to pumping abrasive and viscous fluids.

2. PLUNGER PUMP

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They consist of a cylinder with a reciprocating plunger in

them. The suction and discharge valves are mounted in the head of the

cylinder. In the suction stroke the plunger retracts and the suction

valves open causing suction of fluid into the cylinder. In the forward

stroke the plunger pushes the liquid out of the discharge valve.

Efficiency and common problems: With only one cylinder in

plunger pumps, the fluid flow varies between maximum flow when the

plunger moves through the middle positions, and zero flow when the

plunger is at the end positions. A lot of energy is wasted when the fluid is

accelerated in the piping system. Vibration and "water hammer" may be a

serious problem. In general the problems are compensated for by using

two or more cylinders not working in phase with each other.

3. IMPULSE PUMP

Impulse pumps use pressure created by gas (usually air). In

some impulse pumps the gas trapped in the liquid (usually water), is

released and accumulated somewhere in the pump, creating a pressure

which can push part of the liquid upwards.

Impulse pumps include:

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Hydraulic ram pumps - uses pressure built up internally from

released gas in liquid flow.

Pulser pumps - run with natural resources, by kinetic energy only.

Airlift pumps - run on air inserted into pipe, pushing up the water,

when bubbles move upward, or on pressure inside pipe pushing water up.

THE DYNAMIC PUMP:

Dynamic pumps are one category of pumps under which there are

several classes, two of which are: centrifugal and axial. These pumps

operate by developing a high liquid velocity and converting the velocity to

pressure in a diffusing flow passage. Dynamic pumps usually have lower

efficiencies than positive displacement pumps, but also have lower

maintenance requirements. Dynamic pumps are also able to operate at

fairly high speeds and high fluid flow rates.

Rotodynamic pumps (or dynamic pumps) are a type of velocity

pump in which kinetic energy is added to the fluid by increasing the flow

velocity. This increase in energy is converted to a gain in potential energy

(pressure) when the velocity is reduced prior to or as the flow exits the

pump into the discharge pipe. This conversion of kinetic energy to

pressure can be explained by the First law of thermodynamics or more

specifically by Bernoulli's principle.

Dynamic pumps can be further subdivided according to the means in

which the velocity gain is achieved.[3]

These types of pumps have a number of characteristics:

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1. Continuous energy

2. Conversion of added energy to increase in kinetic energy (increase

in velocity)

3. Conversion of increased velocity (kinetic energy) to an increase in

pressure head

One practical difference between dynamic and positive displacement

pumps is their ability to operate under closed valve conditions. Positive

displacement pumps physically displace the fluid; hence closing a valve

downstream of a positive displacement pump will result in a continual

build up in pressure resulting in mechanical failure of either pipeline or

pump. Dynamic pumps differ in that they can be safely operated under

closed valve conditions (for short periods of time).

THE DYNAMIC PUMP TYPES:

for the dynamic pump, it types can be divided into 2 sections which

are for the single phase and multiphase. For the single phase, the pump

that can be concluded are

1. A centrifugal pump

A centrifugal pump consists of an impeller and an intake at its

center. These are arranged so that when the impeller rotates, liquid is

discharged by centrifugal force into a casing surounding the impeller. The

casing is there in order to gradually decrease the velocity of the fluid

which leaves the impeller at a high velocity. This velocity is converted to

pressure which is needed to discharge the fluid.

Some of the advantages of cenrtifugal pumps are, smooth flow

through the pump and uniform pressure in the discharge pipe, low cost,

and an operating speed that allows for direct connection to steam turbines

and electric motors. The centrifugal pump accounts for not less then 80%

of the worlds pump production because it is more suitable for handling

large capacities of liquids than the positive-displacement pump.

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2. Axialflow pump

Axial flow pumps are also called propeller pump. These pumps

develop most of their pressure by the propelling or lifting action of the

vanes on the liquid. These pumps are often used in wet-pit drainage, low-

pressure irrigation, and storm-water applications.

In general, vertical single-stage axial and mixed-flow pumps

are used however, sometimes two-stage axial-flow pumps are

economically more practical. Horizontal axial-flow pumps are used for

pumping large volumes against low pressures and usually employ

siphonic action. When higher pressures are involved, these pumps can be

arranged to operate with siphonic action until the back pressure places

the hydraulic gradient above the pump.

3. Mixed flow pump

Mixed flow pumps, as the name suggests, function as a

compromise between radial and axial flow pumps, the fluid experiences

both radial acceleration and lift and exits the impeller somewhere

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between 0–90 degrees from the axial direction. As a consequence mixed

flow pumps operate at higher pressures than axial flow pumps while

delivering higher discharges than radial flow pumps. The exit angle of the

flow dictates the pressure head-discharge characteristic in relation to

radial and mixed flow.

FACTORS INVOLVES FOR THE PUMP SELECTIONS:

Before you can select a pump that will fit your needs, you must know four

things that are importants which are :

1. The total head or pressure against in which it must operate

2. The desired flow rate

3. The suction lift

4. The characteristics of the fluid

Aquaculture operations imply that you will be pumping water, but you

also need to know such things as the temperature range, the

corrosiveness (is it salty water?), and how much and what kind of trash or

debris such as sand, dirt, leaves, fish or twigs may be in the water. With

this knowledge, you and your dealer can select the proper pump

The total head, suction lift and flow rate are dependent upon the piping

system and the pump’s characteristics. The piping system and the pump

interact to determine the operating point of the pump – flow rate and

pressure

In order to obtain a pumping system that will meet your

requirements, and meet them in an efficient manner, you must match the

pump to the piping system and required flow rate. Manufacturers should

be able to supply a pump curve which shows the performance of the pump

and the allowable operating ranges. Do not plan to operate outside of this

recommended range outside this may damage the pump. Your dealer may

also be able to help you analyze or plan your piping system. Information

on piping systems is also available in the SRAC Publication No. 373, Piping

Systems.

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A cost analysis of pumping willconsider initial cost of capital

investment, annual fixed cost and operating cost. All three costs are

somewhat dependent on each other. The type of pumpingequipment, size

of pipelines, sizeof pumps and type of water supply affect not only the

initial costbut also the fixed cost as well asthe operating cost.

For example, piping systems using large pipes may cost more but

could allow the use of smaller horsepower pumps which cost less, require

smaller power sources and cost less to operate than a piping system with

small diameter pipe. The lowest priced system is not always the best buy,

especially if the lower price means less efficient pumps. To get the most

efficient pump, an analysis should be made of all pumping requirements.

Key points to consider are:

1. net positive suction head(NPSH)

2. priming

3. flexibility

4. corrosion

5. useful life

6. Maintenance

7. quantity pumped

8. pumping head

9. power source

10. economics.

KEY DESIGN PARAMETERS FOR THE PERISTALTIC PUMP:

1. CHEMICAL COMPATIBILITY

For the peristaltic pump, the pumped fluid contacts only in the

inside surface of the tubing thereby negating concern for other

valves, O-ring or seals that might be incompatible woth the fluid

that being pumped.

1.1 the tubing need to be elastomeric.

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- This is used to maintain the circular cross section after millions

of cycles of squeezing in the pump.

- It also will eliminates a variety of non-elastomeric polymers

that hace compatibility with a wide range of chemicals.

1.2 Inside parameter.

- With the given rpm of the pumps, a tube with the larger inside

diameter will produce a higher flow rate compare with the

smaller one. Intuitively, the flow rate is a function of the cross

section area of the tube bore.

1.3 Flow rate

Flow rate is an important customer requirement. The flow rate

in a peristaltic pump is determined by many factors, such as:

- Tube ID - higher flow rate with larger ID

- Length of tube in the pump measured from initial pinch point

near the inlet to the final release point near the outlet - higher

flow rate with longer length

- Roller RPM - higher flow rate with higher RPM

Interestingly enough, increasing the number of rollers doesn't

increase the flow rate, instead it may decrease the flow rate

somewhat by reducing the volume of fluid between the initial pinch

point and the final release point. Increasing rollers does tend to

decrease the amplitude of the fluid pulsing at the outlet by

increasing the frequency of the pulsed flow.

NPSH (NET POSITIVE SUCTION HEAD)

The net positive suction head can be defined as the difference

between the pump inlets stagnation pressure head and the vapor pressure

head.

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In the other word, the NPSH is the amount of energy in the water at

the pump’s inlet. The required NPSH is a characteristic of the pump and

depends on pump design, size and operating conditions. The required

NPSH is determined by the pump manufacturer. The available NPSH must

equal or exceed the required NPSH. The available NPSH is a characteristic

of the piping system. For the system shown in Figure 2, the NPSH may be

calculated as:

(atmospheric pressure – vapor pressure ) - h – friction loss in

pipe

2.3

The vapor pressure in this equation is dependent upon water

temperature and both it and the atmospheric pressure are expressed in

pounds per square inch while h and friction loss are expressed in feet.

The NPSH can be increase by:

1. Lower the pump or raised the inlet reservoir level.

2. Use larger diameter of pipe

3. Reroute the piping system such that fewer minor losses

4. Shorten the length of the pipe upstream of the pipe

5. Use a smoother pipe

6. Use elbow woth minor loss coefficient

REFERENCES:

1. Pumps and Pumping Operations, Nicholas P. Cheremisinoff & Paul N.

Cherenisinoff - Prentice Hall, 1993.

2. Perry's Chemical Engineers' HANDBOOK, 6th edition, McGraw-Hill,

1984.

3. Pump Handbook, Igor J. Karassik et. al., 2nd edition, McGraw-Hill,

1986

4. Introduction to insulin pump therapy for children and adolescent, Jill

Gethin, February 2013.