Open Circuit Detector

8/11/2019 Open Circuit Detector

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CHAPTER ONE

INTRODUCTION

1.1 GENERAL INTRODUCTION

An open circuit is a kind of electric circuit in which the path that the

electron follows cannot be completed because of an open gap that cannot

ow through ow. Hence open circuit in a pipeline can be dened as an

opening or a leak along the pipe or at the pipe joints.

Pipelines are principal devices for natural gas transportation, and

lots of large scale pipeline networks have been constructed in many

countries in the past ! years. However, leaks, which are the main faults

of gas pipelines, can cause serious problems related not only to the

environment but also to economy. "herefore, many methods and

techni#ues for leak detection with various applicability and restrictions

have been proposed to prevent further loss and danger $%uhlbauer,

&!!'. "he primary methods include acoustic monitoring, optical

monitoring, gas sampling, soil monitoring, ow monitoring, magnetic u(

leakage, and dynamic model)based methods.

1.2 STATEMENT OF THE PROBLEM

*or oil companies, open circuits in pipeline $leaks' are one of the

major causes of failure because of their signicant length in remote and

harsh areas causing human monitoring not to be e+ective. "hus, there is


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an increasing and urgent need of a method that ensures an e+ective

monitoring of these pipelines. "his still remains a challenging task since

the operational pipelines are subject to comple(, highly nonlinear

temporal and spatial processes making it dicult to di+erentiate between

faults and stochastic system behaviors.

-(isting open circuit $leak' detection system cannot be really relied

upon. Hence employment of a new prole "-%P-/A"0/- P/1*23-4 2ts

basic principle is based on the temperature prole of the environment

along the outside of the pipeline. 5hen a leak occurs in a pipeline, it

creates a temperature disturbance in the environment surrounding the

pipe. *or open circuits in pressuri6ed gas pipelines the escaping gas will

generate a cold 6one in the environment surrounding the pipe due to 7oule

"homson e(pansion.

*or pipelines carrying heavy crude oil the oil is often transmitted at

temperatures signicantly above ambient in order to maintain a

reasonable oil viscosity. A pipeline open circuit would therefore create a

local warning of the environment surrounding the pipeline. 8o at the

detection of any of the above systems, there is a bu66ing alarm with a

visual indication of open circuit alert.

9.: AIMS AND OBJECTIVES


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"he aim of the project work is to construct and test an open circuit system

which can be applied along the joints of pipelines.

1;7-


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CHAPTER TWO

LITRATURE REVIEW

2.1 INTRODUCTION

1pen circuits $leaks' waste both a precious natural resource and

money. A large percentage of water, gas or oil usually is lost from the

distribution systems in transit from the treatment?depot plant to theconsumer. 3eakage inevitably also results in secondary economic loss in

the form of damage to the distribution network itself $e.g. erosion of pipe

bedding and major pipe breaks' and to the foundations of roads and other

manmade structures. 3eaky pipes also create a public health risk, as every

leak is a potential entry point for contaminants if pressure should drop in

the system. -conomic cost and scarcity mandate that a systemic leakage

control program be developed. 2n such a program, there are two

components> product $transported li#uid?uid' audits and leak detection

surveys. Product audits measure li#uid?uid ow into and out of the

distribution system, or parts of it, and to help identify those parts of the

distribution system that have e(cessive leakage. However, uid?li#uid


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audits do not identify the specic location of a leak. "o nd the specic

location needing repair, a leak detection survey must be performed

$Hunaidi et al., &!!!'.

*igure &.9 Picture of an oil pipeline with pipe joints

@etection of uid loss due to leakage from underground distribution

pipes represents a major challenge to scientists and engineers. "he key to

the solution is threefold> selection of the right combination of sensing

e#uipment, proper adaptation of procedure for each eld operation, and

data analysis. 8ince each problem is uni#ue considering soil conditions,

type of distribution system, ground li#uid conditions, and intensity of the

leak, it is essential that a pre)tested combination be used to e+ectively

devise the appropriate corrective measures in the shortest possible time.

"esting and guessing in the eld might rush a wrong decision.

2.2 CLASSIFICATION OF DETECTORS

1pen circuit?leak detection methods are broadly classied in terms of

internal and e(ternal monitoring methods> internal methods involving

intrusive measurement to monitor uid state, and e(ternal methods


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applied to the environmental condition of a pipe. "his project construction

and work is wholly on the e(ternal method $hard ware method'.

;ose and 1lson $9:',


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"here are a variety of methods that can detect natural gas pipe line

leaks, ranging from manual inspection using trained dogs to advanced

satellite based hyper spectral imaging $


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ethane. "he primary advantage of gas sampling methods is that they are

very sensitive to very small concentrations of gases. "herefore, even very

tiny leaks can be detected using gas sampling methods. "he techni#ue is

also immune to false alarms. "he disadvantages of the technology are

that detection is very slow and limited to the local area from which the

gas is drawn into the probe for analysis. "herefore the cost of monitoring

long pipelines using gas sampling methods is very high.

8123 %1E2"1/2E %-"H1@

2n soil monitoring methods, the pipeline is rst inoculated with a

small amount of tracer chemical. "his tracer chemical will seep out of the

pipe in the event of a leak. "his is detected by dragging an instrument

along the surface above the pipeline. "he advantages of the method

include very low false alarms, and high sensitivity. However, the method is

very e(pensive for monitoring since trace chemicals have to be

continuously added to the natural gas. 2n addition, it cannot be used for

detecting leaks from pipelines that are e(posed.

*low monitoring devices measure the rate of change of pressure or

the mass ow at di+erent sections of the pipeline. 2f the rate of change of

pressure or the mass ow at two locations in the pipe di+ers signicantly,

it could indicate a potential leak. "he major advantages of the system

include the low cost of the system as well as non)interference with the

operation of the pipeline. "he two disadvantages of the system include

the inability to pinpoint the leak location, and the high rate of false

alarms.


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8oftware based dynamic modeling monitors various ow parameters at

di+erent locations along the pipeline. "hese ow parameters are then

included in a model to determine the presence of natural gas leaks in the

pipeline. "he major advantages of the system include its ability to monitor

continuously, and non)interference with pipeline operations. However,

dynamic modeling methods have a high rate of false alarms and are

e(pensive for monitoring large network of pipes.

2.3 SENSOR SELECTIONS

"he sensor selection of this work is selected based on the following

considerationsF

Pipeline uid characteristics

Pipeline mechanical characteristics

P2P-32E- *302@


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as compressibility measures the deviation of a real gas from ideal

behavior in regard to inter)molecular forces, elasticity and volume

occupancy.


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"he op)amp was originally developed for use with analog computers but

now they found place in almost all aspect of electronics. "he op)amp has

the following ideal characteristicsF

2nnite voltage gain

2nnite input impedance

2nnite bandwidth.

2n practice however there are deviations from ideal conditions due to

manufacturing processes and other physical conditions the various

components might be subjected to which make up the op)amps. ;elow

show the actual characteristics of JAK9 op)amp.

=oltage gain L 9!Cd; $numerical gain M &!!!!!!.!'

2nput impedance L 9%N

1utput impedance L KI!!N

;andwidth L up to 9%H6

"he voltage gain and bandwidth are two parameters that must be

critically looked, for successfully application of this device. %ore

information about the parameters could be gotten from 2< date sheets

Vo!" A#V$% ..........................................................................................&.9

5here A!M open loop voltage gain.

And V$%" V& 'V'....................................................................................&.&

@ue to the very high A!, =outwill tend to saturate upon any di+erence in

input. 1ther op)amp circuits include, inverting and non L inverters

ampliers, summing ampliers, unity gain bu+ers etc.


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2. GATES

*igure &.& Pin conguration of a !99 EAE@ gate

"he !99has four separate &)input EAE@ gates which you can use

independently.

EAE@ gate is a combination of AE@ gate and E1" gate. 2n other words,

output of AE@ gate is connected to the input of a E1" gate as shown

below.

2EP0" A 10"P0"

"he bipolar transistors whose operation depends on the ow of both

minority and majority carriers, and the unipolar or eld e+ect transistors

$called *-"s' in which current is due to majority carriers only $either

electrons or holes'. "he transistor as a switch operates in class A mode.

2n this mode of bias the circuit is designed such that current ows without

any signal present.

"he value of bias current is either increased or decreased about its mean

value by the input signal $if operated as an amplier' or 1E and 1** by

the input signal if operated as a switch.

Ib

Vin

Rb

V+

IcRc


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*igure &.9


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According to Hewes $&!!K' diodes allow electrical to ow in only one

direction. "he arrow of the circuit shows the direction in which the current

can ow. @iodes are electrical version of a value and early diodes were

actually called valves.

1rdinary diode can split into two typesF signal diodes which pass

small current of 9!!mA or less and rectier diodes which can pass large

currents.

/-


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"his is a special kind of diode which permits current to ow in the

forward direction as normal, but will also allow it to ow in the reverse

direction when the voltage is above a certain value)the breakdown

voltage known as the 6ener voltage. "he 6ener voltage of a standard

diode is high, but if a reverse current above that value is allowed to pass

through it, the diode is permanently damaged. Bener diodes are designed

so that their 6ener voltage of that diode no matter how high the reverse

bias voltage is above the 6ener voltage.

2. COUNTERS

rouping of ip)ops together so that they act as a data store

produces a register.


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will free6e on the output that is currently high. 2ts minimum supply voltage

is Cv to 9Iv.

1utputs ,, I Q=


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"he 3%:I series are precision integrated)circuit temperature

sensors, whose output voltage is linearly proportional to the


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/ated for full bIIW to a9I!W< range

8uitable for remote applications

3ow cost due to wafer)level trimming

1perates from to :! volts

3ess than C! mA current drain

3ow self)heating, !.!G !< in still air

Eonlinearity only g$? !< typical

3ow impedance output, !.9 X for 9 mA load

2. PASSIVE COMPONENTS

2n this section the description and function of the electronic

component used in the construction of this work are discussed. Passive

devices are components that cannot gain but used to establish levels or

limits to current or power. "ypical elements that fall into the passive

category are resistors, capacitors and inductors

/-828"1/

A resistor is a two)terminalpassiveelectronic componentwhich

implements electrical resistanceas a circuit element. 5hen a voltage = is

applied across the terminals of a resistor, a current 2 will ow through the

resistor in direct proportionto that voltage. "his constant of

proportionality is called conductance, . "he reciprocal of the

conductance is known as the resistance/, since, with a given voltage =, a
http://en.wikipedia.org/wiki/Terminal_(electronics)http://en.wikipedia.org/wiki/Passivity_(engineering)http://en.wikipedia.org/wiki/Electronic_componenthttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Direct_proportionhttp://en.wikipedia.org/wiki/Resistancehttp://en.wikipedia.org/wiki/Terminal_(electronics)http://en.wikipedia.org/wiki/Passivity_(engineering)http://en.wikipedia.org/wiki/Electronic_componenthttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Direct_proportionhttp://en.wikipedia.org/wiki/Resistance


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larger value of / further YresistsY the ow of current 2 as given by 1hmVs

law>

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

&.C

/esistors are common elements of electrical networksand electronic

circuits and are ubi#uitous in most electronic e#uipment. Practical

resistors can be made of various compounds and lms, as well as

resistance wire$wire made of a high)resistivity alloy, such as nickel)

chrome'. /esistors are also implemented within integrated circuits,

particularly analog devices, and can also be integrated into hybridand

printed circuits.

"he electrical functionality of a resistor is specied by its resistance>

common commercial resistors are manufactured over a range of more

than orders of magnitude. 5hen specifying that resistance in an

electronic design, the re#uired precision of the resistance may re#uire

attention to the manufacturing toleranceof the chosen resistor, according

to its specic application. "he temperature coecientof the resistance

may also be of concern in some precision applications. Practical resistors

are also specied as having a ma(imum powerrating which must e(ceed

the anticipated power dissipation of that resistor in a particular circuit> this

is mainly of concern in power electronics applications. /esistors with

higher power ratings are physically larger and may re#uire heat sinking. 2n
http://en.wikipedia.org/wiki/Ohm's_lawhttp://en.wikipedia.org/wiki/Ohm's_lawhttp://en.wikipedia.org/wiki/Electrical_networkshttp://en.wikipedia.org/wiki/Resistance_wirehttp://en.wikipedia.org/wiki/Integrated_circuitshttp://en.wikipedia.org/wiki/Hybrid_circuithttp://en.wikipedia.org/wiki/Printed_circuit_boardhttp://en.wikipedia.org/wiki/Orders_of_magnitudehttp://en.wikipedia.org/wiki/Engineering_tolerance#Electrical_component_tolerancehttp://en.wikipedia.org/wiki/Temperature_coefficienthttp://en.wikipedia.org/wiki/Power_(physics)http://en.wikipedia.org/wiki/Heat_sinkhttp://en.wikipedia.org/wiki/Ohm's_lawhttp://en.wikipedia.org/wiki/Ohm's_lawhttp://en.wikipedia.org/wiki/Electrical_networkshttp://en.wikipedia.org/wiki/Resistance_wirehttp://en.wikipedia.org/wiki/Integrated_circuitshttp://en.wikipedia.org/wiki/Hybrid_circuithttp://en.wikipedia.org/wiki/Printed_circuit_boardhttp://en.wikipedia.org/wiki/Orders_of_magnitudehttp://en.wikipedia.org/wiki/Engineering_tolerance#Electrical_component_tolerancehttp://en.wikipedia.org/wiki/Temperature_coefficienthttp://en.wikipedia.org/wiki/Power_(physics)http://en.wikipedia.org/wiki/Heat_sink


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a high voltage circuit, attention must sometimes be paid to the rated

ma(imum working voltage of the resistor

*igure &.: 8chematic symbol of a resistor.

the rst band, green, has a value of I and

the second band, blue, has a value of C, and is counted as IC. "he third

band, yellow, has a value of 9!, which adds four !Vs to the end, creating

IC!,!!! [ at \&] tolerance accuracy. IC!,!!! [ changes to IC! k[ \&]

$as a kilo) is 9!:'.
http://en.wikipedia.org/wiki/Engineering_tolerancehttp://en.wikipedia.org/wiki/Engineering_tolerance


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-ach color corresponds to a certain digit, progressing from darker to

lighter colors, as shown in the chart below.

"able &.9 8howing the colour code of a resistor

Co*o+1,!

-%/

2%/

-%/

3+/-%/

(0*!$*$+)

4!-%/

(!o*+%)

T0.

Co5$%!

;lack ! ! Z9!!

;rown 9 9 Z9!9

\9] $*' 9!! ppm/ed & & Z9!& \&] $' I! ppm1rang

e: : Z9!: 9I ppm

Oellow Z9! &I ppmreen I I Z9!I \!.I] $@';lue C C Z9!C \!.&I] $


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A capacitor is basically made up of two metallic plates separated by

some insulting material called dielectric. "he metallic plates may be of

aluminium and dielectric may be paper, mica, ceramic, etc. A capacitor is

known by its dielectric. 8o we have paper capacitors, mica capacitors, and

ceramic capacitors and so on.


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"able &.9 A table of capacitors and their dielectric constant and strength.

%A"-/2A3 @2-3-


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E1E)P13A/2B-@

"hese are made by joining two polar capacitors in back position

or both the electrode is using o(ide lm. "hese have no polarity and

therefore can be connected without considering positive or negative

terminals. "hese can be used for A< appliances. -(amples include

- "antalum electrolytic capacitors-

Plastic capacitors

=A/2A;3-


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i Air capacitors

ii "rimmer

iii Padder

iv =aractor capacitors

"able &.& colour coding chart for (ed capacitors


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decade counter divider. "he !9K is arranged so that on the th pulse, the

count is reset. -ach 3-@ will light se#uentially from 3-@ 9 to 3-@ G then

back to 3-@ 9 etc. ;etween the transmitter and the receiver are the lined

conductors on a band round the pipe joint. 5hen there is an open circuit,

one of the conductorsT breaks indicating an open circuit hence the 3-@

connected to the conductor remains 1**. As the !9K has limited driving

capabilities, then each output is bu+ered by a !I!. "his provides

sucient current boost for long cables and the transmitter and receiver

3-@Vs. "he receiver is simply G 3-@Vs with a common wire.

8econdly, the sensor detector, its basic principle is based on the

temperature prole of the environment along the outside of the pipeline.

5hen a leak occurs in a pipeline, it creates a temperature disturbance in

the environment surrounding the pipe. *or open circuits in pressuri6ed gas

pipelines the escaping gas will generate a cold 6one in the environment

surrounding the pipe due to 7oule "homson e(pansion.

*or pipelines carrying heavy crude oil the oil is often transmitted at

temperatures signicantly above ambient in order to maintain a

reasonable oil viscosity. A pipeline open circuit would therefore create a

local warning of the environment surrounding the pipeline. 8o at the

detection of any of the above systems, there is a bu66ing alarm with a

visual indication of open circuit alert.

3.1 DESIGN ANAL6SIS


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*or every design and construction, one of the most objectives is to

achieve a 9!!] working piece at reduced cost using available local

materials. 2n line with standard specication and re#uirements, this work

is in agreement. 2t is useable, easy to maintain and eco)friendly.

3.2 POWER SUPPL6 STAGE

P15-/ 80PP3O 8"A-

"he power supply is obtained from the rectication output of a &!?9&=

A< output of a step)down transformer.


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=3-@ M =oltage drop by the 3-@

23-@ M


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A 9& v transformer would be used as stated above, to allow for drops,

which might occur due to low ac input voltage from utility supply.

"he rectier is designed with four diodes which form a pull wave bridge

network,


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;ut M

....................................................................................................... :.I

< M

.......................................................................................................... :.C

M $where dt M C.Kms for I!h6'

M

M :.&G:9:K&I ( 9!):

M :&G.:Jf

A preferred valued of ::!!Jf was employed for the power stage.

A voltage regulator of = $3%KG!' was also employed to stabili6e and

regulate the power supply voltage to =.

3.3 OSCILLATOR STAGE

"he oscillator stage comprises of the popular


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3.4 SENSOR STAGE

"he circuit employs the use of 3%:I. 3%:I is a precision integrated

circuit temperature sensor whose output voltage is linearly proportional to

the


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"1 8-E81/ Q

/9I /9&

*igure :.& 8chematic diagram of the comparator stage

/99and /9&form a potential divider. "o drop the regulated

voltage to a low voltage.

Assumption,

let =/& M !.9I=

;ut =/& M /9& ? $/99Q /9&' ( =QRRRRRRRRRR.:.K

5here =/&is the drop across /9&and =Qis the regulated voltage at v.

letting /99 M 9!!k

!.9I=M /9&? $9!!DQ /9&' (

9ID Q!.9I /9&M /9&

9ID M G.GI/9&

/& M 9Ik? G.GI

M 9.Kk

M &k preferred value

/99M 9!!k, /9&M &k


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3. SWITCHING TRANSISTOR STAGE

"he switching transistor switches the bu66er and the light emitting

diode 1E. "he transistor as a switch operates in class A mode. A base

resistor is re#uired to ensure perfect switching of the transistor in

saturation. @iode @I protects the transistor from back emf that might be

generated since the relay coil presents an inductive load.

2n this case /


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22;;

5here,5here,

2


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CHAPTER FOUR

CONSTRUCTION9 TESTING AND RESULTS

4.1 CONSTRUCTION


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"he circuit was rst assembled on a project board unit by unit starting

with the power supply, sensor, and comparator and switching, and each

unit of the design was tested separately. 3ater on the whole unit were

tested and coupled together still on the project board. Afterwards, the

entire system was transferred to the =ero)board or strips board where

there were properly soldiered together. Above is the circuit diagram of an

open circuit detector.

4.2 COMPONENTS USED

/-828"1/8

/9 M 9D

/& M 9!%

/: L /9! M 9D

/99 M 9!!D

/9& M &D

/9:, /9 M 9!D


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"/AE828"1/8

;< 9!G

2E"-/A"-@


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4.3 TESTING

*or the sensor stage, it was tested and the results tabulated as follows.

"able .98howing the output result of the sensor at di+erent intelligent

touch

8-E82"2=- "1

"-%P-/A"0/-

10"P0" 1;8-/=A"21E

At any temperature

change

A change in voltage e#uivalent of the

temperature.

*or the band conductor test> At any slight open circuit of the pipe, a

conductor strip is broken on the band, hence causing the 3-@ not to light

up.

-E"2/- 8O8"-% "-8"

After packaging was done, the entire system was tested and the result

obtained were as desired.

"able .&8howing the entire system test and result obtained.

-E-/A3 "-8" 10"P0" 1;8-/=A"21E

7oints tight $no leakage' All 3-@s 1E, bu66er 1**.

7oints loosed $open circuit' 1pen circuited 3-@ 1**, bu66er

1E.


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4.4 RESULTS OBTAINED

"able .9 shows the test results obtained after carrying out the test

UNITS:

SECTIONS

TESTED

INSTRUMENTS

USED FOR

TESTING

RESULTS

OBTAINED

RESULTS

E;PECTED

Power supply @igital

multimeter

9&v at the

transformer

output of I!H6

"he same result

as obtained and

e(pected.8ensor unit @igital

multimeter

A directly

varying voltage

output with

temperature

8ame result as

obtained


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4. PACKAGING

"o protect the circuit against damage from rough handling, unnecessary

fall and carelessness, the circuit re#uires good packaging. Packaging

ensures durability of the work, easy movement and makes it presentable.

"he above mentioned were carried out using a plastic casing providing a

sit so the circuit will be (ed and secured.

4. PROBLEMS ENCOUNTERED

2n actuali6ing this project so many challenges were encountered as listed

below

9. 0nsteady power supply $a national issue',

&. 0navailability of some great sensitive detectors

:.


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CHAPTER FIVE

SUMMAR6 AND CONCLUSION

.# SUMMAR6

"he open circuit detector automatically detects any open circuit

$leakage' on the pipeline joints and gives a visual and an audio alerts.

2t is user friendly and suitable for all roads where decongestion is

necessary. 2ts construction is well design, making room for easy

maintenance. "he components used are readily available, as they are

locally obtained from the local market.

.1 CONCLUSION

Having considered some of its ecient notication abilit ,resultant e+ect

of prompt attention to mails, its easy to maintain nature and implicitly its

promise of even better and improved versions in the future makes it a

worthwhile venture.

"he project was #uite a challenging one to accomplish. "here is high initial

capital cost but low running or maintenance cost as compared to

conventional method of open circuit detector. "he project has e(posed us

to marry the analog and digital electronics that are being taught in the

classroom and at the workshop.

"he construction was done so as to give easy access for maintenance.


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.2 RECOMMENDATIONS.

8ubse#uent work on this project should consider adding a satellite

transmitter and receiver so that it can be monitored from any part of

the world. 5ith solar panel system for is power supply to make it

independent from the national grid supply. A routine maintenance should always be done on the device to keep

it at optimal performance. And the sensor should be protected from

direct contact with the soil. Projects of this nature which possess good market prospect should

be given good nancial sponsorship, so that it could be produced in

large #uantity, in order to monitor our oil pipelines accurately.


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REFERENCE

9. &. Bhang B. 5., Oe H. 5ang . B. et al, 3eak detection in

transport pipelines using enhanced independent component

analysis and support vector machines, 3ecture Eotes in Published by

communication Alchemy 2nc.


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9!. "homas -. Dissel $&!!!', 2ndustrial -lectronics, 0.8.A> Prentice

Hall 2nc E7

99. Published

by 3ongman

9:. 9. Andberg


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Open Circuit Detector

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