project report porthcawl comprehensive school

Porthcawl Comprehensive School Lafarge Tarmac

“SMART Early Warning System”

Team: Andrew Philips (Team Leader)

Jack Bevan

Curtis Naughton

Jasmeen Dawes

Tom Parsons

Keiren Waring

Aneurin Weale

Matthew Williams

Engineer: Mr Phil Jones

Teacher: Mr Richard Lawson

March 2014

Porthcawl Comprehensive School March, 2014

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Contents

Contents ..................................................................................................................................... 1 Executive Summary ................................................................................................................... 3 Introduction ............................................................................................................................... 4 Analysis of Problem .................................................................................................................. 5 Research into Existing Technologies ........................................................................................ 6

Capacitance Sensing ........................................................................................................................... 6

Analog Devices ................................................................................................................................... 6

Ultrasonic range finder ...................................................................................................................... 7

Data Processing ......................................................................................................................... 8 Procedure ................................................................................................................................. 11

Initial Meeting .................................................................................................................................. 11

Research ........................................................................................................................................... 11

About Tarmac ................................................................................................................................... 12

Site visit ............................................................................................................................................ 13

Final Solution .................................................................................................................................... 16

Design Development ............................................................................................................... 17 Hardware .......................................................................................................................................... 17

Python Scripts .......................................................................................................................... 19 Prototype Testing ............................................................................................................................. 24

Results, Discussion and Evaluation ......................................................................................... 26 Environmental Benefits .................................................................................................................... 26

Development Costs .......................................................................................................................... 27

Cost Benefits .................................................................................................................................... 28

Health and Safety ............................................................................................................................. 28

Wider Scope of Project ..................................................................................................................... 29

Conclusion ............................................................................................................................... 30 Appendix ................................................................................................................................. 31


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Executive Summary

In the world of business, orders must be fulfilled in a timely, efficient and cost effective manner. This is equally true in the field of engineering. Business success can be me made or broken on the strength of a having a company reputation of making deliveries on time. If orders are fulfilled quickly then costs can also be controlled and savings can be passed on to customers. This project will investigate ways in which the manufacture and delivery of asphalt can be maintained and made robust to ensure customer satisfaction.

In Asphalt manufacture, lime stone is quarried, crushed and mixed with Bitumen and stone dust to make a solid and robust construction material for the laying of roads and motorways. In the case of Lafarge Tarmac at Cornelly, the stone is quarried on site. The bitumen it is mixed with is supplied from a refinery in Birkenhead and stored in four 50,000 litre tanks. The stone is mixed with the bitumen as the product is required. Clearly, the supply of stone is in abundance thanks to the onsite quarry. However, the bitumen supply must be more closely monitored to ensure a constant amount is on site to meet the orders received. Currently, this level is monitored by engineers on site. This is a laborious and time consuming process which takes manpower that could be usefully employed elsewhere. A better solution would be an automatic system that could alert on site engineers that supplies are being depleted so orders could be made on time. This would ideally take the form of an alert being sent to the engineers wherever they are instead of valuable staff being limited to a small radius around the tanks.

This project will outline the design, prototyping and testing of a low cost automatic level warning system that will notify staff of low bitumen levels via SMS text message. This will aim to deliver improvements in efficiency, cost saving and will also provide environmental benefits through a small, low cost and easily implemented unit.


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Introduction

In order to maximise cost savings and ensure that highest customer service levels are maintained on the company’s Asphalt plants, “full loads” of bitumen must be ordered and delivered on time. Predicting how much to order and when is currently an art form and needs to be turned into a science if costly “part loads” are to be eliminated. Reducing the number of part loads is a key performance indicator for the asphalt business and this system will help reduce cost and improve safety at our sites.

The project aim was to design and build a working prototype system to monitor and predict the usage of bitumen in bitumen storage tanks such that an automated SMS text message will be generated and sent to the site manager (or his/her deputy) alerting him/her of the need to re-‐order a “full load” of bitumen on a given date.

In addition, a monthly spreadsheet will also be generated from that system showing, bitumen ordered, dates and times plus cost savings as compared to historical data in the previous financial year which include costly and unwanted part loads. Additional features in the software and reporting will also be required and these will be discussed with the team throughout the project execution.


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Analysis of Problem

Scope: To design and manufacture a scaled working system to carry out the following functions:

1. Monitor fluid level in a vertical cylindrical tank and predict the usage to a pre-‐determined level.

2. At that pre-‐determined level, an alarm will be triggered sending a signal to a PC which in turn

will send out an SMS text message to the site managers’ mobile phone. The message will be

sent only between the hours of 06:00am and 18:00pm, Mon-‐Sat, 50 weeks p.a. The message

will advise the manager to re-‐order a full load of fluid (bitumen)to maintain stock levels,

protect plant availability and customer service levels.

3. In any event, a text message will be sent if no bitumen has been ordered within any single

24 day period as a quality requirement to refresh the stock

4. A monthly spreadsheet will also be required (in Excel format) illustrating how many loads

were flagged up via text message during any particular calendar month showing the total

cost of those loads both in month and cumulative timescales.

5. The same spreadsheet will also be required to show the cost saving of not having to order

part loads in the month/year (using 2012 historical data for reference).

4No.Bitumen Tanks50,000L Capacity Each

To Asphalt Plant

Full

Refill

Empty

Level indication to PC

SMS text message to manager to re-‐order bitumen

(At pre-‐ determined level)

Text message Produce monthly Spreadsheet showing savings

EESW 2013


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Research into Existing Technologies

Capacitance Sensing

Sensor Technics

With over 20 years of extensive experience in the development and manufacture of unique optical and MEMS sensor solutions, our brand portfolio includes strong and highly specialised brands. We serve custom development and manufacturing at 14 sites around the world.

Analog Devices Analog Devices offers the world’s first high-‐precision, fully integrated Capacitance-‐to-‐Digital Converters (CDC), that address the complex and difficult signal processing challenges of direct capacitance-‐to-‐digital conversion. The award-‐winning Capacitance-‐to-‐Digital Converter (CDC) technology enables high accuracy capacitance sensing for Industrial, Automotive, and Consumer applications.

http://www.sensortechnics.com/en/products/liquid-‐level-‐sensors-‐and-‐switches/capacitive-‐level-‐sensors/clc/

http://www.analog.com/en/analog-‐to-‐digital-‐converters/capacitance-‐to-‐digital-‐converters/products/index.html?gclid=CIGd2LS9yboCFfHItAodDXoAcw#Capacitive_to_Digital_Converters


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Ultrasonic range finder Ultrasonic sensors (also known as transceivers when they both send and receive, but more generally called transducers) work on a principle similar to radar or sonar which evaluates attributes of a target by interpreting the echoes from radio or sound waves respectively. Ultrasonic sensors generate high frequency sound waves and evaluate the echo which is received back by the sensor. Sensors calculate the time interval between sending the signal and receiving the echo to determine the distance to an object.

This technology can be used for measuring wind speed and direction (anemometer), tank or channel level, and speed through air or water. For measuring speed or direction a device uses multiple detectors and calculates the speed from the relative distances to particulates in the air or water. To measure tank or channel level, the sensor measures the distance to the surface of the fluid. Further applications include: humidifiers, sonar, medical ultrasonography, burglar alarms and non-‐destructive testing. Systems typically use a transducer which generates sound waves in the ultrasonic range, above 18,000 hertz, by turning electrical energy into sound, then upon receiving the echo turn the sound waves into electrical energy which can be measured and displayed.

The technology is limited by the shapes of surfaces and the density or consistency of the material. Foam, in particular, can distort surface level readings


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Data Processing i) Database to look up/ convert raw data into usable data

Polyspot -‐ PolySpot's information management solutions can be used to extract and enrich raw data, so that these data can be used by and distributed to users.

Universal and long-‐term connectivity -‐ Connectivity with the various applications that a company uses is essential for raw data collection. With a library of over 100 application connectors, ‘PolySpot Silo Breaker’ can easily be connected to the majority of market-‐standard content (DMS, CMS, WCMS, DBMS, web, RSS), guaranteeing long-‐term access from a single point to all of a company's applications.

From raw data to enriched information -‐ Freshly-‐produced, out-‐of-‐context data is neither useful nor meaningful. PolySpot has developed conversion and semantic enrichment modules to standardise and contextualise raw data to produce information that can


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instantly be used by a range of different search services. In order to combine high information availability and maximum indexing versatility, PolySpot has developed a unique architecture, capable of managing a variety of processes in both synchronous and asynchronous mode.

Shared and distributed information -‐ Enriched information is distributed via a range of different search services, each of which is capable of providing users with all available information from a single interface. PolySpot's enterprise search applications can be adapted to suit business-‐specific requirements, with unrivalled configuration and display options (simple search interface configuration, relevance fine-‐tuning, specific settings based on the user's profile and context) and intelligent searching and browsing functions (auto-‐complete, spelling suggestion, thesaurus/ontology integration, property-‐based browsing, multi-‐view management, alerts, collaborative functions, etc.).

ii) Automatically generate a text based on information

Text Local -‐ Easily text important information, offers & alerts. Attach pictures, files, web-‐links & surveys.

Text local help over 102,383 businesses send up to 40 million messages per month. Over the last seven years, Textlocal have been at the forefront of business mobile messaging. Our in-‐house, award winning, technical team like nothing better than to innovate and build tools optimized for delivery on mobile phones that meet real business needs. We deal with businesses every day. We know the challenges you face and we understand your needs.

Our emphasis is on efficiency, integration and ease of use. Our Messenger platform has been built with this in mind, along with some really useful added extras such as tracking, surveys, attachments, ticketing, analytics, campaign management tools and much more.

Our ethos encompasses a complete dedication to exceeding customer expectations, and this has been highly commended by industry experts. The awards have just kept coming. We have been listed as a Media Momentum top 20 fastest growing digital agency across Europe for the last three years, won a Chamber Business Award for innovation, a DMA Honours award for marketing Innovation and also shortlisted for the best marketing services company. This adds to our collection including Global Messaging Award for our exceptional messaging infrastructure, and Digital and Media Entrepreneurs of the year.

Our ever growing staff base is made up of passionate, dedicated people who believe completely in how Textlocal can revolutionise the communication structure of any business. As the awards keep coming in and our customers remain extremely satisfied, we know Textlocal is an exciting company to be involved with on any level.


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Twilio SMS -‐ Send & receive SMS with twilio messaging

Global Text Messaging API -‐ Build apps that send and receive SMS using phone numbers and short codes, perfect for businesses and organisations. The API enables users to communicate with their app and send messages when they wish.

Build Intelligent Communications -‐ Twilio lets you use standard web languages to build SMS and voice applications. We’re connected to carrier networks globally and expose them to you via a clean, powerful web API. So bring your favorite programming language, a web server, and build the next generation of communications with us.

Cloud Powered -‐ We’re built in the cloud. Our API is always available, continuously upgraded and auto-‐scales to meet your needs. When you move your communications to the cloud, there are no tricky VPNs to configure or SMPP binds to manage. Just send us your message via HTTP, and we’ll deliver it anywhere in the world.


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Procedure

Initial Meeting We first met Mr Phil Jones at the Introduction meeting in Bridgend where he announced himself as our Engineer. Phil introduced himself and the company that he was involved in which was ‘Lafarge Tarmac’. He then went on to explain in more detail what kind of company Lafarge was and the sort of work that they are involved in. After explaining some details about the company, Phil moved onto the task in hand which was the project to be given to and developed by our team. He gave us the definition of the problem and helped us to visualise this by giving us information sheets and diagrams. Phil then explained in more detail the type of solution they were looking for and why this solution was required. We then began to discuss the problem, thinking of and writing down key features that the possible solution must include and how we could go about developing these solutions. After a lengthy discussion, we felt quite confident on the project and thought that a suitable solution was quite possible and therefore were looking forward to working with Phil and Lafarge. Since the initial discussion, we have kept in touch with Phil regularly with him attending our meetings at least once a month. With the purpose of these visits being to see the progress and development of the project first-‐hand and in order to give us any data, information or advice that we may have requested in order to help with the completion of the task. Research into level monitoring

Research Through the course of seeking the best solution for the project, a large amount of research was conducted by the team members into the different types of systems currently in use for measuring levels of fluids, sending text messages and processing data. Many of these were ruled out as either too expensive or too difficult to make.


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About Tarmac Lafarge Tarmac is the UK's leading supplier of aggregates and asphalt. They combine industry-‐leading innovation with an unrivalled supply and distribution network that includes over 100 quarries, 70 dedicated asphalt plants and 70 recycling operations. Their products meet the highest standards of sustainability and performance, as you would expect from a market leader. They are responsibly sourced and certified to BES 6001.

Their range of 'Ultimate' aggregate and asphalt solutions have been designed to meet the daily challenges faced by construction professionals. These specialist solutions help their customers deliver outstanding results in shorter timescales, even when faced with challenging requirements or difficult site conditions.

Asphalt (also known as bitumen), is a sticky, black and highly viscous liquid or semi-‐solid form of petroleum. It may be found in natural deposits or may be a refined product; it is a substance classed as a pitch. Until the 20th century, the term asphaltum was also used.

The primary use (70%) of asphalt/bitumen is in road construction, where it is used as the glue or binder mixed with aggregate particles to create asphalt concrete. Its other main uses are for bituminous waterproofing products, including production of roofing felt and for sealing flat roofs.

The terms asphalt and bitumen are often used interchangeably to mean both natural and manufactured forms of the substance. In American English, asphalt (or asphalt cement) is the carefully refined residue from the distillation process of selected crude oils. Outside the United States, the product is often called bitumen. Geological terminology often prefers the term bitumen. Common usage often refers to various forms of asphalt/bitumen as "tar", such as at the La Brea Tar Pits. Another term, mostly archaic, refers to asphalt/bitumen as "pitch". The pitch used in this mixture is sometimes found in natural deposits but usually made by the distillation of crude oil.

Naturally occurring asphalt/bitumen is sometimes specified by the term "crude bitumen". Its viscosity is similar to that of cold molasses while the material obtained from the fractional distillation of crude oil [boiling at 525 °C (977 °F) is sometimes referred to as "refined bitumen".


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At the site, we were briefed about the company’s health and safety guide, which is a prime concern of Lafarge Tarmac. Lafarge Tarmac is keen to play an active part in the community and encourage schools and other interested groups to visit their sites and gain firsthand knowledge of their industry. However, quarries and other areas such as asphalt plants and recycling depots can be dangerous. During the visit, the group had to stay together under the supervision of a guide provided by the company.

Site visit We were invited to visit the Quarry to see the Bitumen tanks in their location and to see the kind of environment in which they the system would be installed.

This was a potentially hazardous environment which meant we had to have a safety lesson and then were issued with protective clothing and equipment.


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When we went out into the quarry, we were taken to the Bitumen tanks in the minibus with a safety car escort and were shown how the bitumen was loaded in to the tanks as there was a delivery taking place at the time.


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We were then taken up to the top of the 10m tall tanks to see where the sensor could be installed.

From here we were taken around the entire quarry site and shown how Lafarge Tarmac first quarries the limestone, treats the stone and finally turns it into asphalt that can be sent all over the area for use in making roads.


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Final Solution The solution we decided on as a team was to use an ultrasonic transmitter/receiver unit with a Raspberry Pi computer. This combination gives the following benefits:

• The chosen sensor is very low cost. We obtained ours from the internet for approximately £2

• The Raspberry Pi is a low cost computing option. Approximately £25. • The software code that we have implemented is very flexible and can be changed

easily to: o Change the message that is sent o Change the number of recipients o Change the number of massages sent o Change the depth at which the message is triggered

• The device can be implemented any number of times across the site with very small amounts of set up or reconfiguration


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Design Development

Once the technology and implementation had been decided on we had to build the system to test it on a small scale in the laboratory. The equipment had been ordered from the internet and the software code was being written. While this was being done, the hardware had to be constructed in order to test the software was working correctly. The software and the hardware were then put together to check the system worked and then put through a period of testing to ensure consistent operation.

Hardware The sensor unit was a basic unit with ultrasonic transmitter and receiver built onto a circuit board with a small amount of circuitry (an oscillator and timing circuits to make the ultrasonic sound waves that are sent by the transmitter).

This small circuit board then required a small amount of circuitry to make it work with the raspberry pi. This circuit was a small interface system to ensure that the voltage provided by the raspberry pi was correct to drive the sensor and the signal supplied by the sensor was correct for the pi to be able to understand.

This circuit was first constructed on a prototyping board to ensure correct operation.


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Once this circuit was tested and could be seen to work reliably it was soldered onto strip board to make the contacts more secure and resilient.

This circuit could then be mounted in a case to protect the more sensitive parts of the circuit from damage. The sensor was interfaced to the Raspberry Pi by using a temporary general input output break out board (GPIO board). This is a temporary measure and, because of the nature of the Pi, these contacts could be made directly to the computer board by soldering. However, this would be a final solution and not for development.


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Python Scripts The software program script for the Raspberry Pi was written in Python code. This is the main programming language for the raspberry pi and is becoming more popular among programmers in many areas of computing.

The following section outlines the Python programme that was created for this project. Unfortunately the formatting has not been retained – this was lost when exporting the programme file from the Pi. This formatting would have taken the form of indenting different parts of the program in order to group sections of the code together.

Some annotation is included in the text in the form of comments. These comments are preceded by a hash icon (#). This is the standard way that programmers annotate software to keep track of their code. The hash sign tells the program to ignore that line as it is not part of the program. Annotation has been added in the boxes on the right of the page.

Ultrasonic distance measure:

import time

import RPi.GPIO as GPIO

def measure():

# This function measures a distance

GPIO.output(GPIO_TRIGGER, True)

time.sleep(0.00001)

GPIO.output(GPIO_TRIGGER, False)

start = time.time()

while GPIO.input(GPIO_ECHO)==0:

start = time.time()

while GPIO.input(GPIO_ECHO)==1:

stop = time.time()

elapsed = stop-‐start

distance = (elapsed * 34300)/2

return distance

def measure_average():

distance1=measure()

time.sleep(0.1)

Functions such as the General Purpose Input Output library must be allocated to this program.

This section of the code is how the Pi is able to measure distance.

The Ultrasonic unit transmits a pulse of high frequency sound waves (GPIO Trigger True) and then starts a timer. The timer is stopped when the echo is detected at the sensor.

This equation then takes the recorded time and mulitplies it by the speed of sound in air. This is approximately 34300 cm/s. This number is then divided by two in order to find the distance from the sensor to the surface of the liquid – not the total path length the sound wave has travelled.


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distance2=measure()

time.sleep(0.1)

distance3=measure()

distance = distance1 + distance2 + distance3

distance = distance / 3

return distance

# Main Script

# Use BCM GPIO references

# instead of physical pin numbers

GPIO.setmode(GPIO.BCM)

# Define GPIO Pins to use on Pi

GPIO_TRIGGER = 23

GPIO_ECHO = 24

print "Ultrasonic Measurement"

# Set pins as output and input

GPIO.setup(GPIO_TRIGGER,GPIO.OUT) # Trigger

GPIO.setup(GPIO_ECHO,GPIO.IN) # Echo

# Set trigger to False (Low)

GPIO.output(GPIO_TRIGGER, False)

try:

while True:

distance = measure_average()

print "Distance : %.1f" % distance

time.sleep(1)

#trigger SMS1 when distance is greater than 40 cm

if distance > 40:

This section of the code takes three measurements of the distance and then takes anmean average of the results. This helps in making the measurement more accurate.

This section of the code begins to define the levels at which the alarms will be raised. This will be short distances set for our model but this can be adjusted very easily for any size of tank or silo.


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sms

except KeyboardInterrupt:

# User pressed CTRL-‐C

# Reset GPIO settings

GPIO.cleanup()

def SMS(

Code to send SMS

# Import required libraries

import urllib # URL functions

import urllib2 # URL functions

# Define your message

message = 'Refill bitumen tank number 1 -‐ Cornelly Quarry'

# Set your username and sender name.

username = '[email protected]'

sender = 'Porthcawl EESW Team

# Your unique hash is available from the docs page

# https://control.txtlocal.co.uk/docs/

hash = '86cee22e249d8e18f09bd0b7bed6821ea6c72cf1'

# Set the phone number

numbers = ('447855272195')

# Set flag to 1 to simulate sending

# To send real message set this flag to 0

test_flag = 1

values = {'test' : test_flag,

'uname' : username,

'hash' : hash,

'message' : message,

'from' : sender,

CTRL-‐C is the standard code to interrupt a program that is running. In this case it is also being used to reset the inputs and outputs of the Pi.

This section of the code will send the message to amobile phone via the internet service “text local”. This service was selected as it enables remote and automatic log in using the provided “Hash Code”

The service requires a administrator to maintain control of the system so our teacher, Mr Lawson has signed in with his details,

This is the Hash code provided by the website

This script can send text messages to individual phones or a group of phones numbers if required. This is where the phone number(s) to be used is entered.

As text messages cost money to send (10p) then we have included the ability to simulate sending a text for testing the system and to keep costs to a minimum during development.


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'selectednums' : numbers }

url = 'http://www.txtlocal.com/sendsmspost.php'

postdata = urllib.urlencode(values)

req = urllib2.Request(url, postdata)

print 'Attempt to send SMS ... '

try:

response = urllib2.urlopen(req)

response_url = response.geturl()

if response_url==url:

print 'SMS sent!'

except urllib2.URLError, e:

print 'Send failed!'

print e.reason

# Import required libraries

import urllib # URL functions

import urllib2 # URL functions

# Define your message

message = 'URGENT! – Level Low: Refill bitumen tank number 1 -‐ Cornelly Quarry'

# Set your username and sender name.

username = '[email protected]'

sender = 'Porthcawl EESW Team’

# Your unique hash is available from the docs page

# https://control.txtlocal.co.uk/docs/

hash = '86cee22e249d8e18f09bd0b7bed6821ea6c72cf1'

# Set the phone number you wish to send

The program will print progress messages on the screen and confirmation that the text has been sent. This is mainly for the development stage as during main use the screen will not be required.

It will tell us if the send has failed or succeeded. This works even in simulated test mode.

This section of the program is a copy and repeat of the previous section. This was the easiest way to enable us to send different messages at different times. This is difficult to see here as the indent formatting did not keep.


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# message to.

numbers = ('447855272195')

# Set flag to 1 to simulate sending

# To send real message set this flag to 0

test_flag = 1

values = {'test' : test_flag,

'uname' : username,

'hash' : hash,

'message' : message,

'from' : sender,

'selectednums' : numbers }

url = 'http://www.txtlocal.com/sendsmspost.php'

postdata = urllib.urlencode(values)

req = urllib2.Request(url, postdata)

print 'Attempt to send SMS ... '

try:

response = urllib2.urlopen(req)

response_url = response.geturl()

if response_url==url:

print 'SMS sent!'

except urllib2.URLError, e:

print 'Send failed!'

print e.reason

Though a repeated part of the program, this is a key part of the operation. This function can be replicated for different distances within the tank allowing early warning messages to be sent, emergency low level messages or test messages.

This function could be expanded by the company at any point and very easily to enable the system to become more flexible depending on changing needs.


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Prototype Testing The prototype system was tested on a small scale. The site where this system would normally be used is a very dangerous environment. The sensor would have to be set up inside the bitumen tank and the bitumen is held at a very high temperature to make sure it remains liquid. This raises the possibility that the sensor would not work properly in his environment but this is impossible for us to test within the scope of this project.

So, to test the concept of the system we built a scale model of the bitumen tank on site, scaled the trigger thresholds in the software and constructed a mount to hold the sensor unit at the top of the tank. After much discussion we finally selected our equipment to use for our testing and display model. The first step in building our model was ordering the equipment. Some of the equipment used was sourced or built in school. For example the casing for our raspberry pi was found and then modified in order to hold the pi and keep it safe. The casing for the ultrasonic sensor was also modified to hold the sensor.

We then used a high speed drill to cut a hole for the tap. We did this by drilling lots of holes close together and then pushing the plastic out. We chose to do it this way as it had the lowest risk of the plastic splitting as we were cutting. We then put the tap in place making sure to use the gaskets provided to stop the risk of leaking. The piping was then attached. We also added stickers to the tanks to make them look more realistic. We have also used a bubble machine in order to make the liquid look like its hot.

To start we needed a container to hold x amount of (material) so before building an actual physical model a design was first created to replicate the specification given.

First purely the cylinder and base were created with the measurements of (insert dimensions) and volume of (insert volume) as shown in fig 1.

Secondly the lid was designed the original design was to cover the entire top surface as shown in fig 2. However later design proved that due to the use of sonar as the method of measurement it was better to have a half covered surface to avoid any echo or at least


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avoid most to give more reliable results when measuring the volume of liquid in the container.

The final result with the sonar device is as shown in fig 3.

Using this rig, the tank was filled and drained many times. First the rig was tested with the test flag set in the software. This meant that the levels could be monitored and the computer would signal that a text message would be sent. Once this was working successfully, the test flag could be removed and so the system would send real text messages over the internet. This was first done for members of the team and our teacher. Then we attempted to send a series of texts to our Engineer, Mr Jones by simply changing the water level in the test tank. This was a great success and showed that the system was reliable in sending the messages.

The only problem we encountered at this stage was that occasionally, the system would send two or three text messages in a row instead of a single text. The reason for this is unknown but the problem of sending too many text messages is better than not sending any.


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Results, Discussion and Evaluation The benefits of this system being implemented in the Tarmac company are broad and far reaching. This section will aim to summarise the main points that will benefit the company.

Environmental Benefits As the bitumen used is ordered and so delivered from Birkenhead, this obviously has an impact on the environment as a whole. The tanker lorries that deliver the bitumen to site have to travel 231 miles (371 km) on their journey from Birkenhead to Cornelly Quarry. This is an unavoidable journey but still causes a significant CO2 contribution to atmospheric pollution. The following table shows how, on average vehicles contribute to global warming with CO2 emissions:

Bitumen is delivered in 25 tonne loads by large tanker trucks. Depending on the size of the truck and engine being used, the CO2 produced is generally between 3.0 and 3.9 kg/tonne/km.

If we take an average pollution rate of 3.4 kg/tonne/km then we can calculate the pollution per journey as follows:

This will be consistent for the 371 km journey so will generate:

Total kg per journey = 371 km x 3.4 kg/km

= 1,261 kg of CO2 per journey

Although the tanker will have unloaded the 25 tonnes of liquid at Cornelly, the return journey must also be factored in as this is an inevitable part of the process.


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Total kg per delivery = 1,261 x 2

= 2,523 kg

It is estimated by the company that unnecessary part loads are ordered on average 10 times each year. This is the type of journey that is caused by poor level control and so the type of pollution our system will aim to eliminate. So the total unnecessary CO2 generated per year:

Total CO2 per year = 2,523 kg x 10

= 25,230 kg CO2 per year

This is a very large amount of pollution that could be reduced very simply by implementing our device.

Development Costs

The costs of developing this system were actually very small. The Raspberry Pi computer generally retails for about £25. The Ultrasonic transceiver costs approximately £2. The cases and hardware were surplus to requirements and so were free to the project though normally they would cost less than £10 in total. The actual cost to create this system in a form that could be used therefore is about £40 in total.

However, there were more costs involved in development than merely constructing the system. The test rig and tanks were the single biggest expense. These alone cost £136. This seems like a very large expenditure when compared to the rest of the system but it was considered important to have a test system that was similar in shape and scale dimensions to the actual storage tanks on site.

The text messaging service used, “Text Local” is a py per use service. It is free to register and gain an account. This account even comes with £10 of free text messages. As testing continued, we began to run out of text messages. We contacted the text service providers and explained the idea behind the EESW scheme and they agreed to provide us with a further 50 text message credits with the offer of more if this did not prove sufficient.


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Cost Benefits

The cost benefits to this system are very significant. These benefits can be outlined as follows:

A full tank of bitumen delivered from Birkenhead is 25 tonnes at £550 per tonne.

This means that each tanker load costs £13,750.

If a part load is required, these loads are 15 tonnes. However, the cost of this delivery is still £13,750. Effectively the company is charged a premium if the tanker is not full. It is therefore in the companies best interest to ensure that only full loads are being ordered.

Each time this happens, although the tanker is delivering 10 tonnes less than normal, the company is still charged for these 10 missing tonnes at £550/tonne. So the company pays £5,500 for bitumen it does not receive.

As mentioned above, this is estimated to happen currently approximately 10 times each year. This equates to £5,500 per tank. Cornelly has 4 tanks so this could be as much as £22,000 per site.

Cornelly also has smaller tanks than other sites in the company. Some quarry sites have 100 tonne tanks instead of 50 tonnes tanks. This will therefore increase the amount of wasted journeys and money.

The cost benefits are also more widespread than straight forward purchasing. The fact that the system will be automatic enables an engineer to be redeployed elsewhere on site instead of having to monitor tank levels. This will help the site to run more efficiently and more productively.

The increased productivity and efficiency will also enable the company to maintain better relationships with their clients and will be able to fulfil more orders more quickly and will therefore help to grow their business and reputation.

Health and Safety

This system also delivers safety benefits. Each time the lorry driver discharges a tanker load of bitumen, he is exposed to liquids held at temperatures in excess of 120 oC. This means he must wear special safety clothing and runs the risk of accidental spills. He is also exposed to the fumes and gases given off by such a dangerous and volatile substance.


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Wider Scope of Project

By the time this project had been finished and tested to prove it worked, we began to realise the full potential of this project. While this has been demonstrated to be a huge benefit to Lafarge Tarmac in the remote monitoring of Bitumen level, it could be used anywhere a level in a container needs to be monitored.

For example, any liquid, not just bitumen, could be monitored. This could include any type of fluid required in manufacturing, chemicals in industrial plants, ingredients in food manufacturing, petrol/diesel levels in mass storage tanks or petrol stations or water in swimming pools. The list of liquids that could be measured is literally endless.

As this system is ultrasonic, it does not necessarily have to be a liquid to be measured. This would work equally well in a farms grain silo, a bread factory’s flour silo or building sites for monitoring sand or cement powder in the construction industry.

This could also be a very important way of helping people in developing countries. For example, this device could be installed in a drinking water well and could alert people of falling water levels so that help can be sought or contingency plans could be put in place.


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Conclusion

The unit designed fulfilled the design brief in operation. It has proved able to detect the level of liquid within a large tank with a high degree of accuracy. It has also proved to be reliable and issued at least one text message each time the liquid threshold levels were reached. Occasionally more than one SMS was transmitted but as previously mentioned this was not seen as an issue as the message would still have got through to the engineer.

The greatest area of success which we did not originally intend to be so great was the proven cost saving that this small unit could, and will achieve. These are complimented by huge savings in environmental factors such as CO2 output and the benefit to the perception of the company by clients and competitors.

As previously mentioned this project has the potential to help wider industry and is not just limited to bitumen monitoring in the manufacture of asphalt. As a team, we have designed, developed and delivered a robust solution to a very challenging problem. This design has been built and tested and has shown that it can work reliably.

The main limitation of the system developed so far is that it cannot at present be installed on site. For this to take place it would have to be formally tested for Electromagnetic Compatibility, safety testing and would need to be ruggedized to make sure it will withstand the harsh environments on site.

However, this would be a relatively small investment and as such, this device has shown that it can provide very substantial cost saving, enormous environmental benefits and can be used in many different situations.


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Appendix

The following appendix shows examples of the systems that were used to ensure the work was completed in an orderly and timely manner.


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Action Log This spreadsheet shows an early example of the progress log that was used to keep track of tasks within the team and to keep our Engineer informed.

project report porthcawl comprehensive school

Documents

contents contents

mr richard lawson

mr phil jones teacher

ultrasonic range finder

existing technologies

executive summary

analysis of problem

capacitance sensing