Engineering - what's it all about?

1

Tuning-in

Task 1              

List the main branches    of engineering.  Combine   your list with others in your

group. Then read this text to find out how many of the branches listed are mentioned.

Engineering is largely a practical activity. It is about putting ideas into action. Civil engineering is concerned with making bridges, roads, airports, etc. Mechanical engineering deals with the design and manufacture of tools and machines. Electrical engineering is about 5 the generation and distribution of electricity and its many

applications. Electronic engineering is concerned with developing components and equipment for communications, computing, and so on.

Mechanical engineering includes marine, automobile, aeronautical,

10

heating and ventilating, and others. Electrical engineering includes electricity generating, electrical installation, lighting, etc. Mining and medical engineering belong partly to mechanical and partly to electrical.

Task 2             

Complete the blanks in this diagram using information  from the  text.

Engineering

Civil                         

1

Electrical

2

Electricity

5

Electrical 6_ installation

Automobile Aeronautical 4

Medical

Reading

Introduction

In your study and work, it is important to think about what you are going to read before you read. This helps you to link old and new knowledge and to make guesses about the meaning of the text. It is also important to have a clear purpose so that you choose the best way to read. In this book, you will find tasks to make you think before you read and tasks to help you to have a clear purpose when you read.

Task 3               

Study these illustrations.    They show some of the areas in which engineers

work. Can you identify them? What kinds of engineers are concerned with these areas

-

electrical, mechanical, or both?

Task 4                    

Now read the  following texts to check your answers to Task 3. Match each

text to one of the illustrations above.

Transport: Cars, trains, ships, and planes are all products of mechanical engineering. Mechanical engineers are also involved in support services such as roads, rail track, harbours, and bridges.

Food processing: Mechanical engineers design, develop, and make 5 the machines and the processing equipment for harvesting, preparing and preserving the foods and drinks that fill the supermarkets.

Medical engineering: Body scanners, X-ray machines, life-support systems, and other high tech equipment result from mechanical and electrical engineers combining with medical experts to convert ideas

10

   

into life-saving and life-preserving products.

Building services: Electrical engineers provide all the services we need in our homes and places of work, including lighting, heating, ventilation, air-conditioning, refrigeration, and lifts.

Energy and power: Electrical engineers are concerned with the 15 production and distribution of electricity to homes, offices, industry, hospitals, colleges and schools, and the installation and maintenance of the equipment involved in these processes.

Source: Adapted from

Turning ideas into action,

Institution of Mechanical Engineers, and

Engineering a Career,

Institution of Electronics and Electrical Incorporated Engineers.

Language study

deals/is concerned with

What is the link between column

A

and column

B?

A                                         B

mechanical machines

electrical electricity

Column

A

lists a branch of engineering or a type of engineer. Column

B

lists things they are concerned with. We can show the link between them in a number of ways:

1

     

Mechanical engineering deals with machines.

2

     

Mechanical engineers deal with machines.

3

     

Mechanical engineering is concerned with machines.

4

     

Mechanical engineers are concerned with machines.

5

   

Task

5

Machines are the concern of mechanical engineers.

Match each item in column

A

with an appropriate item from column

B

and

link the two in a sentence.

A

B

1

marine

a

air-conditioning

2

aeronautical

b

roads and bridges

3

heating and ventilating

c

body scanners

4

electricity generating

d

cables and switchgear

5

automobile

e

communications and equipment

6

civil

f

ships

7

electronic

g

planes

8

electrical installation

h

cars and trucks

9

medical

i

power stations

Word study

Word stress

Words are divided into syllables. For example:

engine

engineer

engineering

en.gme

en.gin.eer

en.gin.eer.ing

Each syllable is pronounced separately, but normally only one syllable is stressed. That means it is said more slowly and clearly than the other syllables. We say

'engine

but

encjin'eer.

A good dictionary will show the stressed syllables.

Task 6 CES

1

2

3

4

5

6

7

3

                    

9

10

Task

7

Listen to these words. Try to mark the stressed syllables.

machinery

mechanical

machine

install

installation

electricity

electrical

electronics

aeronautical

ventilation

Writing

Fill in the gaps in the following description of the different branches of engineering using information from this diagram and language you have studied in this unit.

Engineering

Electrical

Electronic

Mechanical

Electricity

generating

Lighting

Marine Automobile Aeronautical Heating and

ventilating

Electrical

installation

Mining

Medical

The main branches of engineering are civil,'      ,

         

, and

electronic. Mechanical engineering is

!

machinery

of all kinds. This branch of engineering includes

!           

, automobile,

, and heating and ventilating. The first three are concerned with

transport:

______________________________________

, cars and planes. The last

___

with air-

conditioning, refrigeration, etc.

Electrical engineering deals with

       

from generation to use.

Electricity generating is concerned with ™stations. Electrical

installation dealscables, switchgear, and connecting up

electrical equipment.

Two branches of engineering include both

_f

and 1!

engineers. These are mining and

'1

      

engineering. The former deals

with mines and mining equipment, the latter with hospital1 ’ of                                          all

kinds.

Listening

Task 8

E3

Listen to these short extracts. To which branch of engineering do these

engineers belong?

Task 9             E3

Listen again. This time note the words which helped you decide on your

answers.

Mechanisms

Tuning-in

Task 1

Identify these simple mechanisms. Try to explain the principles on which they operate.

Reading

Scanning a text

Scanning is the best strategy for searching for specific information in a text. Move your eyes up and down the text until you find the word or words you want. Again, try to ignore any information which will not help you with your task.

Task 2

Scan the text opposite quickly to find out which of these mechanisms are mentioned.

1

                                                             

 cam

4

foot pump

2

                                                             

 tap

5

escalator

3

     

pendulum

Mechanisms

Mechanisms are an important part of everyday life. They allow us to do simple things like switch on lights, turn taps, and open doors. They also make it possible to use escalators and lifts, travel in cars, and fly from continent to continent.

5

   

Mechanisms play a vital role in industry. While many industrial processes have electronic control systems, it is still mechanisms that deliver the power to do the work. They provide the forces to press steel sheets into car body panels, to lift large components from place to place, to force plastic through dies to make pipes.

1

   

All mechanisms involve some kind of motion. The four basic kinds of motion are:

Rotary: Wheels, gears, and rollers involve rotary movement.

Oscillating: The pendulum of a clock oscillates - it swings backwards and forwards.

15

Linear: The linear movement of a paper trimmer is used to cut the edge of the paper.

Reciprocating: The piston in a combustion engine reciprocates.

Many mechanisms involve changing one kind of motion into another type. For example, the reciprocating motion of a piston is changed

20

into a rotary motion by the crankshaft, while a cam converts the rotary motion of the engine into the reciprocating motion required to operate the valves.

Task 3

Now read the text to find the answers to these questions.

1

    

What does a cam do?

2

    

What does oscillating mean?

3

    

How are plastic pipes formed?

4

    

What simple mechanisms in the home are mentioned directly or indirectly?

5

    

What is the function of a crankshaft?

6

    

Give an example of a device which can produce a linear movement.

7

    

How are car body panels formed?

8

    

What do mechanisms provide in industry?

Writing

Ways of linking ideas, 1

When we write, we may have to describe, explain, argue, persuade, complain, etc. In all these forms of writing, we use ideas. To make our writing effective, we have to make sure our readers can follow our ideas. One way of helping our readers is to make the links between the ideas in our writing.

What are the links between these pairs of ideas? What words can we use to mark the links?

1

   

Mechanisms are important to us.

2

   

They allow us to travel.

3

   

Mechanisms deliver the power to do work.

4

   

They play a vital role in industry.

5

   

Friction is sometimes a help.

6

   

It is often a hindrance.

Mechanisms are important to us because/since/as they allow us to travel.

Sentence 4 is the

result

of sentence 3. We can link 3 and 4 like this:

Mechanisms deliver the power to do work so they play a vital role in industry.

Mechanisms deliver the power to do work; therefore they play a vital role in industry.

Sentence 6

contrasts

with sentence 5. We can link 5 and 6 like this:

Friction is sometimes a help but it is often a hindrance.

Task 4

Show the links between these sets of ideas using appropriate linking words.

1

    

Copper is highly conductive.

It is used for electric wiring.

2

    

Weight is measured in newtons.

Mass is measured in kilograms.

3

    

Nylon is used for bearings.

It is self-lubricating.

4

    

ABS has high impact strength.

It is used for safety helmets.

5

    

The foot pump is a class 2 lever.

The load is between the effort and the fulcrum.

6

    

Friction is essential in brakes.

Friction is a nuisance in an engine.

Load

7

     

The upper surface of a beam is in compression. The lower surface is in tension.

8

     

Concrete beams have steel rods near the lower surface. Concrete is weak in tension.

Language study

Dealing with technical terms

One of the difficult things about the English of engineering is that there are many technical terms to learn. Newer terms may be the same, or almost the same, in your own language. But many terms will be quite different and you may not always remember them.

When this happens, you will have to use whatever English you know to make your meaning clear.

The same thing may happen in reverse when you know a technical term but the person you are communicating with does not recognize it. This may happen in the

Speaking practice

tasks in this book. Again, when this happens, you will have to make your meaning clear using other words.

Task 5                  

The technical words in column

A

are similar in meaning to the more general

English in column

B.

Match them.

A

B

1

oscillates

a

changes

2

rotates

b

large, thin, flat pieces

3

reciprocates

c

moving stairs

4

has a linear motion

d

goes round and round

5

converts

e

movement

6

motion

f

goes in a line

7

escalator

g

swings backwards and forwards

8

sheets

h

goes up and down

Task 6                  

Try     to explain how this simple mechanism operates using whatever English

you know. Write your explanation down. Compare your explanation with the technical explanation given on page 4 of the Answer Book. Learn any technical terms which are unfamiliar to you.

Treadle linkage

Speaking practice

Task 7               

Work in pairs,

A

and

B.

Each of you has a diagram of a cam. Describe your

diagram to your partner. Your partner shoufcftry to reproduce your diagram from the spoken description you provide.

Student A:

Your diagram is on page 177.

Student B:

Your diagram is on page 181.

Thes text on the next page will help you with the vocabulary you need.

Cams are shaped pieces of metal or plastic fixed to, or part of, a rotating shaft. A 'follower' is held against the cam, either by its own weight or by a spring. As the cam rotates, the follower moves. The way in which it moves and the distance it moves depends on the

5

   

shape of the cam. Rotary cams are the most common type. They are used to change rotary motion into either reciprocating or oscillating motion.

If you do not understand what your partner says, these questions and phrases may be helpful.

1

             

 Could you say that again/repeat that, please?

2

             

 What do you mean by X?

3

     

Where exactly is the X?

4

     

What shape is the X?

5

     

How does the X move?

If your partner does not understand you, try to rephrase what you say.

Forces in engineering

Tuning-in

Task 1

Working in your group, try to explain these problems.

1

    

Why doesn’t the ship sink?

2

    

What makes the spring stretch and what keeps the weight up?

3

    

Why doesn’t the box slide down the slope?

Reading 1

Predicting

As you learnt in Unit 1. it is important to think about what you are going to read before you read. Do not start to read a text immediately. One way to help your reading is to think about the words which might appear in the text. The title might help to focus your thoughts. Which words might appear in a text with the title

Forces in engineering?

Task 2

The text you are going to read is called

Forces in engineering.

Here are some of the words it contains. Can you explain the link between each word and the title of the text?

weight     buoyancy    equilibrium

elasticity magnitude   resultant

newton     gravity

Now read the text. Use the information in the text to check the explanations you made in Task 1.

Task 3

Forces in engineering

To solve the ship problem, we must look at the forces on the ship (Fig.

1). The weight, W, acts downwards. That is the gravity force. The buoyancy force, B, acts upwards. Since the ship is in equilibrium, the resultant force is zero, so the magnitudes of B and W must be the

5

  

same.

B                                  

B-W=0

Another very important force in engineering is the one caused by elasticity. A good example of this is a spring. Springs exert more force the more they are stretched. This property provides a way of measuring force. A spring balance can be calibrated in newtons, the

1

      

unit of force. The block in Fig. 2 has a weight of 10 newtons. The

weight on the balance pulls the spring down. To give equilibrium, the spring pulls up to oppose that weight. This upward force, F1, equals the weight of the block, W.

f F,=W

v w

Fig. 2

It is important to get the distinction between mass and weight 15 absolutely clear. Mass is the quantity of matter in an object. Weight is the force on that object due to gravity. Mass is measured in kilograms, whereas weight, being a force, is measured in newtons.

We have looked at buoyancy, elasticity, and gravity. There is a fourth force important in engineering, and that is friction. Friction is a help in

20

some circumstances but a hindrance in others. Let us examine the forces on the box (Fig. 3). Firstly, there is its weight, W, the gravity force, then there is the reaction, R, normal to the plane. R and W have a resultant force trying to pull the box down the slope. It is the friction force, F, acting up the slope, that stops it sliding down.

Reading 2

Grammar links in texts

One of the ways in which sentences in a text are held together is by grammar links. In this extract, note how each expression in italics links with an earlier expression.

Another very important force in engineering is

the one

caused by elasticity. A good example of

this

is a spring. Springs exert more force the more

they

are stretched.

This

property provides a way of measuring force.

Sometimes these links cause problems for readers because they cannot make the right connection between words in different parts of a text.

Study these common grammar links:

1

    

A repeated noun becomes a pronoun.

Springs

becomes

they.

2

    

A word replaces an earlier expression.

Force in engineering

becomes

one.

3

    

A word replaces a whole sentence or clause.

Springs exert more force the more they are stretched

becomes

This property.

Task 4

With which earlier expressions do the words in italics link? Join them as in the example above.

Friction in machines is destructive and wasteful.

It

causes the moving parts to wear and

it

produces heat where

it

is not wanted. Engineers reduce friction by using very highly polished materials and by lubricating

their

surfaces with oil and grease.

They

also use ballbearings and roller bearings because rolling objects cause less friction than sliding

ones.

Source: S. Larkin and L. Bembaum (eds.). The Penguin Book of the Physical World

Language study

The present passive

Study these instructions for a simple experiment on friction.

Wood block

Horizontally calibrated spring balance

Fig. 4

1

     

Place a block of wood on a flat surface.

2

     

Attach a spring balance to one end of the block.

3

     

Apply a gradually increasing force to the balance.

4

     

Note the force at which the block just begins to move.

5

     

Pull the block along so that it moves at a steady speed.

6

     

Note the force required to maintain movement.

7

     

Compare the two forces.

When we describe this experiment, we write:

A block of wood

is placed

on a flat surface. A spring balance

is attached

to one end of the block.

This description uses the present passive. We form the present passive using

is/are

+ past participle.

Task 5

Complete this description of the experiment using the present passive.

A block of woodon a flat surface. A spring balance

I

to one end of the block. A gradually increasing force

I

 

to the

balance. The force at wrhich the block just begins to move

     

The block

_________

along at a steady speed. The force required to maintain

movement

_________

. The two forces_

____

It is found that the first

force is greater than the second.

What does this experiment show?

Listening

Listening to lectures

The listening passage you are going to hear is an extract from a typical engineering lecture. Here are some of the features of lectures.

Incomplete sentences: Spoken language is not divided neatly into sentences and paragraphs. For example:

Now what I thought 1 might do today

...

What we are going to talk of...

Repetition and rephrasing: Lecturers often say the same thing more than once and in more than one way. For example:

It will turn, revolve.

Signpost expressions: Lecturers often use expressions to help the students know what they are going to do next, what is important, etc. For example:

What we are going to talk of is the extension of a force.

In the same way as when reading, it is helpful to think about the topic of a lecture before you listen. The topic here is

The Moment of a Force.

Can you explain the links between these words from the lecture and the topic? Use a dictionary to help you if necessary.

Task 6

turning   distance     product

pivot     perpendicular leverage

fulcrum   hinge

Task 7

E3

Now listen to the lecture to check your explanations.

Task 8

During the lecture, the lecturer drew this diagram on the board. Which of the words in Task 6 can be used to talk about the diagram?

Task 9

Here are some signpost expressions from the lecture. What do you think the lecturer is indicating each time? Select from the labels below,

a

to

e.

We're going to talk about the moment of a force.

If you can think of a spanner...

But what you have to remember is ...

Something simple to illustrate.

I’m thinking of a practical job.

Why do we put a handle there on the door?

Is that understood? All right?

Well that is then a little explanation of how you calculate moments.

Emphasizing an important point Showing that the lecture is over Checking that the students can follow him Introducing the topic of the lecture Giving examples to illustrate the points

Task 10

Listen to the tape again and answer these questions according to the information given by the lecturer.

1

2

3

4

5

What advantage does a longer spanner offer in loosening a tight nut?

What is the formula for calculating the moment of a force?

W7hy is it sometimes difficult to apply a force at right angles in a motor car engine?

Why is the handle of a door at the edge?

Write down the formulae for calculating force and distance.

The electric motor

Tuning-in

Task 1

Working in your group, list as many items as you can in the home which use electric motors. Which room has the most items?

Reading

Skimming

In Unit 3 you studied scanning - locating specific information quickly. Another useful strategy is reading a text quickly to get a general idea of the kind of information it contains. You can then decide which parts of the text are worth reading in more detail later, depending on your reading purpose. This strategy is called

skimming.

Task 2

Skim this text and identify the paragraphs which contain information on each of these topics. The first one has been done for you.

a

What electric motors are used for

paragraph 1

b

The commutator

c

Why the armature turns

d

Electromagnets

e

Effect of putting magnets together

f

The armature

para

In an electric motor an electric current and magnetic field produce                   

^

a turning movement. This can drive all sorts of machines, from wrist-watches to trains. The motor shown in Fig. 1 is for a washing machine. It is a universal motor, which can run on direct current or

5

   

alternating current.

An electric current running through a wire produces a magnetic                        

2

field around the wire. If an electric current flows around a loop of wire with a bar of iron through it, the iron becomes magnetized. It is called an electromagnet; one end becomes a north pole and the

1

   

other a south pole, depending on which way the current is flowing around the loop.

►

Fig. 1

If you put two magnets close together, like poles - for example,                        

3

two north poles - repel each other, and unlike poles attract each other.

15

    In a simple electric motor, like the one shown in Fig. 2, a piece of                  

4

iron with loops of wire round it, called an armature, is placed between the north and south poles of a stationary magnet, known as the field magnet. When electricity flows around the armature wire, the iron becomes an electromagnet.

Fig. 2

►

20

The attraction and repulsion between the poles of this armature                          5

magnet and the poles of the field magnet make the armature turn.

As a result, its north pole is close to the south pole of the field magnet. Then the current is reversed so the north pole of the armature magnet becomes the south pole. Once again, the

25

attraction and repulsion between it and the field magnet make it turn. The armature continues turning as long as the direction of the current, and therefore its magnetic poles, keeps being reversed.

To reverse the direction of the current, the ends of the armature                       

6

wire are connected to different halves of a split ring called a 30 commutator. Current flows to and from the commutator through small carbon blocks called brushes. As the armature turns, first one half of the commutator comes into contact with the brush delivering the current, and then the other, so the direction of the current keeps being reversed.

Source: Adapted from 'Inside out: Electric Motor',

Education Guardian

Task

3       Match each  of these diagrams  with    the  correct   description. A. B. C. or D. One

of the descriptions does

not

match any of the diagrams. (The diagrams are in the correct sequence, but the descriptions are not.)

Motor run on direct current

A

The armature turns a quarter of a turn. Then electric contact is broken because of the gap in the commutator, but the armature keeps turning because there is nothing to stop it.

B

When current flows, the armature becomes an electromagnet. Its north pole is attracted by the south pole and repelled by the north pole of the field magnet.

C

When a universal motor is run on direct current, the magnetic poles in the armature change while those of the field magnet remain constant.

D

When the commutator comes back into contact with the brushes, current flows through the armature in the opposite direction. Its poles are reversed and the turn continues.

Language study

Describing function

Try to answer this question:

What does an electric motor do?

When we answer a question like this, we describe the function of something. We can describe the function of an electric motor in this way:

An electric motor converts electrical energy to mechanical energy.

We can emphasize the function like this:

Task 4

The function of an electric motor is to convert electrical energy to mechanical energy.

Match each of these motor components to its function, and then describe its

function in a sentence.

Component

Function

1

armature

a

transfers rotation from the motor

2

bearings

b

create an electromagnetic field

3

brushes

c

converts electromagnetic energy to rotation

4

commutator

d

reverses the current to the armature

5

drive shaft

e

support the drive shaft

6

field windings

f

supply current to the armature

Writing

Describing components

Task 5

DC motor

Dismantle this simple dc motor into its components by completing the labelling of the chart below.

 

3_________                                      Loop       of  wire

i

i

I

4

Now study this description of the motor.

A simple dc motor

consists of

a field magnet and an armature. The armature

is placed between

the poles of the magnet. The armature

is made up of

a loop of wire and a split ring

known as

a commutator. The loop

is connected to

the commutator. Current is supplied to the motor through carbon blocks

called

brushes.

To write a description, you need to use language to:

1

     

dismantle a piece of equipment into its main parts. These expressions will help:

consists of

                         X

A A

is made up of

        XandY

is composed of

                   Y

2

     

name components:

Carbon blocks

as

brushes.

called

3

     

locate components:

The armature

is placed between

the poles.

4

     

connect components:

The loop

is connected to

the commutator.

Task 6

Complete the text with the help of the diagram on the next page. Use the following words:

are made up is placed is composed consists

A transformer    of two coils, a primary and a secondary. The coils

are wound on a former which is mounted on a core. The coils

       

of

a number of loops of wire. The core

       

of thin pieces of soft iron. U-

and T-shaped pieces are used. The former

       

on the leg of the T.

Now label the diagram opposite using the completed text.

1 Transformer

ll_n

Word study

Study these expressions for describing how components are connected to each other.

A is bolted to B. = A is connected to B with bolts.

A is welded to B. = A is connected to B by welding.

A is fixed to B. = no specific method given

Task 7

Explain each of these methods of connection.

1

      

screwed

2

      

soldered

3

      

attached

4

      

wired

5

      

bonded

6

      

glued

7

      

riveted

8

      

welded

9

      

brazed

nailed

Central heating

Tuning-in

Task 1

How can you heat a house in cold weather? List the possible

ways.

Reading

Predicting

In Unit 5 we learnt how using the title can help us to predict

the contents

of a text. Diagrams are also very useful in helping the reader to

make the

right guesses about what a text will contain. Before you read a text,

read the

title and look at any diagrams it contains.

Task 2

1

2

3

4

5

Using the diagram, try to explain the function of these

components:

the pilot light

the heat exchanger fins

the flue

the thermostat

the pump

Flue

Pump

Burner

Outer casting

Burnt gases

Finned heat exchanger

S:

er

thermostat

control

Cold water in

Scan this text quickly to check the explanations you made in Task 2. You may not find all the information you want.

Task 3

Gas central heating

Most gas central heating works on the 'wet' system of heat transfer between water flowing through pipes. Atypical system includes a boiler, a network of pipes, a feed, and expansion tank, radiators, and a hot water storage system.

1

  

In conventional boilers, water is heated by gas burners. It is then pumped around the central heating system and the hot water storage cylinder. The flow of gas to the burner is controlled by a valve (or valves) which can be operated by a time switch or by a boiler thermostat, hot water cylinder thermostat, or by a

10

 

thermostat located in one of the rooms.

Air is necessary for complete combustion and is supplied to the burners either from inside the house, when adequate ventilation must be ensured, or directly from outside through a balanced flue.

Water is circulated through a heat exchanger above the burner. The 15 heat exchanger is made of tubes of cast iron or copper, which resist corrosion. Both types use fins to increase the surface area in contact with water, which improves the transfer of heat. A thermostat located in the boiler causes the gas control valve to shut off when the water temperature reaches the pre-set level.

20

After being pumped through a diverter or priority valve, water circulates around either one of two loops of pipework, which act as heat exchangers. One loop passes through the inside of the hot water storage cylinder in a coil arrangement. Heat is transferred to the surrounding water, which can then be drawn off from this 25 cylinder from various hot taps in the house when required. The loop then returns to the boiler for re-heating.

The other loop of the circuit passes to the radiators, which provide room heating. Several radiators are generally connected, where one pipe provides the hot water input and the other carries the cold 30 water back to the boiler. In this way, all radiators receive hot water directly from the boiler.

Source: 'Inside out: Central Heating',

Education Guardian

Task 4

Put these statements in the correct sequence. The first and last have been done for you.

a  

Water is circulated through a heat exchanger. I

b  

The loop returns to the boiler for re-heating.    

           

c  

One loop passes through the inside of the hot water storage

cylinder in a coil of pipes.

d

Water is heated by gas burners.

e  

The hot water is pumped through a diverter valve.

f   

The other loop of the circuit passes to the radiators.

g

Cold water from the radiators returns to the boiler.    7

Use the statements in Task 4 to label the stages shown in this diagram of a heating system.

Task 5

Language study

Time clauses

What is the relationship between these pairs of actions? How can we link each pair to show this relationship?

1

     

Cold water passes through a heat exchanger.

The water is heated.

2

     

The water is heated.

It reaches a pre-set temperature.

3

     

The water is heated.

It is pumped to a diverter valve.

4

     

The water temperature reaches the right level.

The gas control valve shuts off.

We can show how actions are linked in time by using time clauses.

We can use

as

to link two connected actions happening at the same time. For example:

1

     

/4s

cold water passes through a heat exchanger, the water is heated.

We can use

until

to link an action and the limit of that action. For example:

2

     

The water is heated until it reaches a pre-set temperature.

Note that

until

normally comes between the stages.

We can use

after

to show that one action is followed by another action. For example:

3

     

After the water is heated, it is pumped to a diverter valve.

We can use

when

to show that one action happens immediately after another. For example:

4

     

When the water temperature reaches the right level, the gas control valve shuts

off.

Note that when the time word comes first in the sentence, a comma I.) is used after the time clause.

Link these sets of actions with appropriate time words.

1

     

Task 6

The system is switched on.

Cold water passes through a heat exchanger in the boiler.

2

     

The water passes through the heat exchanger.

The water becomes hotter and hotter.

The water reaches a pre-set level.

3

     

The water temperature reaches the pre-set level.

A thermostat causes the gas control valve to shut off.

4

     

The water is pumped to a diverter valve.

The water goes to the hot water cylinder or the radiators.

5

     

 Hot water passes through the inside of the hot water storage cylinder in a coil arrangement.

Heat is transferred to the surrounding water.

6

     

The hot water flows through the radiators.

The hot water loses heat.

7

     

The water passes through the radiators.

The water returns to the boiler.

Word study

Task 7

The words listed in the first column of this table are common in descriptions of technical plant. They describe how substances are moved from one stage of the process to the next. Some of these words can be used for any substance; others are more specific. Write an X under Solids, Liquids, or Gases if the word on the left can be used to talk about them. The first example has been done for you.

Solids               Liquids           Gases

carried                      XXX

circulated

conveyed

distributed

fed

piped

pumped

supplied

Refrigerator

Tuning-in

Task 1               

Study this    diagram. It explains how a refrigerator works. In your group try to

work out the function of each of the numbered components using the information in the diagram.

o o o o

Reading

Dealing with unfamiliar words, 1

You are going to read a text about refrigerators. Your purpose is to find out how they operate. Read the first paragraph of the text below. Underline any words which are unfamiliar to you.

Refrigeration preserves food by lowering its temperature. It slows down the growth and reproduction of micro-organisms such as bacteria and the action of enzymes which cause food to rot.

You may have underlined words like

micro-organisms, bacteria,

or

enzymes.

These are words which are uncommon in engineering. Before you look them up in a dictionary or try to find translations in your own language, think! Do you need to know the meaning of these words to understand how refrigerators operate?

You can ignore unfamiliar words which do not help you to achieve your reading purpose.

Now read the text to check your explanation of how a refrigerator works. Ignore any unfamiliar words which will not help you to achieve this purpose.

Fridge

para

Refrigeration preserves food by lowering its temperature. It slows

1

down the growth and reproduction of micro-organisms such as bacteria and the action of enzymes which cause food to rot.

Refrigeration is based on three principles. Firstly, if a liquid is                            

2

1

  

heated, it changes to a gas or vapour. When this gas is cooled, it changes back into a liquid. Secondly, if a gas is allowed to expand, it cools down. If a gas is compressed, it heats up. Thirdly, lowering the pressure around a liquid helps itto boil.

To keep the refrigerator at a constant low temperature, heat must                     

3

10

be transferred from the inside of the cabinet to the outside. A refrigerant is used to do this. It is circulated around the fridge, where it undergoes changes in pressure and temperature and changes from a liquid to a gas and back again.

One common refrigerant is a compound of carbon, chlorine, and                       4

15

fluorine known as R12. This has a very low boiling point: -29°C. At normal room temperature (about 20°C) the liquid quickly turns into gas. However, newer refrigerants which are less harmful to the environment, such as KLEA 134a, are gradually replacing R12.

The refrigeration process begins in the compressor. This                                   

5

20

compresses the gas so that it heats up. It then pumps the gas into a condenser, a long tube in the shape of a zigzag. As the warm gas passes through the condenser, it heats the surroundings and cools down. By the time it leaves the condenser, it has condensed back into a liquid.

25

Liquid leaving the condenser has to flow down a very narrow tube                    

6

(a capillary tube). This prevents liquid from leaving the condenser too quickly, and keeps it at a high pressure.

►

As the liquid passes from the narrow capillary tube to the larger                       7

tubes of the evaporator, the pressure quickly drops. The liquid

30

turns to vapour, which expands and cools. The cold vapour absorbs heat from the fridge. It is then sucked back into the compressor and the process begins again.

The compressor is switched on and off by a thermostat, a device                    

8

that regulates temperature, so that the food is not over-frozen.

Source: 'Inside out: Fridge',

Education Guardian

Language study

Principles and laws

Study these extracts from the text above. What kind of statements are they?

1

    

If a liquid is heated, it changes to a gas or vapour.

2

    

If a gas is allowed to expand, it cools down.

3

    

If a gas is compressed, it heats up.

Each consists of an action followed by a result. For example:

Action                         Result

a liquid is heated it changes to a gas or vapour

These statements are principles. They describe things in science and engineering which are always true. The action is always followed by the same result.

Principles have this form:

If/When

(action-present tense), (result-present tense).

Link each action in column

A

with a result from column

B

to describe an important engineering principle.

A Action

B Result

1

a liquid is heated

a

it heats up

2

a gas is cooled

b

there is an equal and opposite

3

a gas expands

reaction

4

a gas is compressed

c

it changes to a gas

5

a force is applied to a body

d

it extends in proportion to the force

6

a current passes through a wire

e

it is transmitted equally throughout

7

a wire cuts a magnetic field

the fluid

8

pressure is applied to the surface

f

a current is induced in the wire

of an enclosed fluid

g

it cools down

9

a force is applied to a spring fixed

h

it sets up a magnetic field around the

at one end

wire

i

it changes to a liquid

Word Study

Verbs and related nouns

Each of the verbs in column

A

has a related noun ending in

-er

or

-or

in column B. Complete the blanks. You have studied these words in this and earlier units. Use a dictionary to check any spellings which you are not certain about.

A Verbs                 B Nouns

For example:

refrigerate refrigerator

1

     

condense   

________

2

     

                ___

evaporator

3

     

compress

4

     

resist     

________

5

5

      

generate

6

      

conduct

8

7

      

radiate 10 control

Writing

Describing a process, 2: location

Study this diagram. It describes the refrigeration process.

In Unit 13 we learnt that when we write about a process, we have to:

1

     

Sequence the stages

2

     

Locate the stages

3

     

Describe what happens at each stage

4

     

Explain what happens at each stage

For example:

sequence location                  description

The refrigeration process begins in the compressor. This compresses the gas

explanation so

that it heats up.

In this unit we will study ways to locate the stages.

Put these stages in the refrigeration process in the correct sequence with the help of the diagram above. The first one has been done for you.

a

The liquid enters the evaporator.

b

The gas condenses back into a liquid.

c

The vapour is sucked back into the compressor.

 

d

The gas is compressed.       I

e

The liquid turns into a vapour.

f

The gas passes through the condenser.

g

The liquid passes through a capillary tube.

h

The high pressure is maintained.

There are two ways to locate a stage in a process.

1

     

Using a preposition + noun phrase. For example:

The liquid turns to vapour

in the evaporator.

The gas cools down

in the condenser.

2

     

Using a

where-cVause.

a relative clause with

where

rather than

which

or

who.

to link a stage, its location and what    happens there. For example:

The warm gas passes through the condenser,           

where it heats               the

surroundings and cools down.

The refrigerant circulates around the fridge,

where it undergoes changes in pressure and temperature.

Complete each of these statements.

The gas passes through the compressor, where It passes through the condenser, where

The liquid passes through a capillary tube, where The liquid enters the evaporator, where

The cold vapour is sucked back into the compressor, where

Add sequence expressions to your statements to show the correct order of events. For example:

First the gas passes through the condenser...

Make your statements into a paragraph adding extra information from the text in Task 2 if you wish. Then compare your paragraph with paragraphs

6. 7.

and

1

 

from the text.

Scales

Tuning-in

Complete this table of common quantities and forces to be measured in engineering, the units in which they are measured, and the instruments you use to measure them.

Quantity/Force

Unit

Instrument

1

Current

Ammeter

2

Newton

Force gauge

3

Velocity

km/hr

4

°C

Thermometer

5

Thickness

Micrometer

6

Ohm

Ohmmeter

7

Voltage

8

Pressure

Manometer

How can you measure weight accurately? What alternatives are there? If you cannot name the instruments, draw them.

Task 3

What do you think are the advantages of electronic scales over mechanical

scales?

Reading 1

Meaning from context

Task 4

Read the first two paragraphs of this text and try to fill in the missing words.

More than one answer is possible for some of the blanks. Then check your answer to Task 3 using the completed text.

Electronic scales

para

l

The electronic kitchen scaletakes a larger load and is 7

1

__________

accurate than its mechanical counterpart. Whereas   a

 

1

_________ scale may have a capacity of about 3kg. broken 4     

2

5g units, the electronic scale can

I           

a

load of*

______

to 5kg broken into units of 5g or even 2g.

The scale

Z___

by converting the load increase on its   

2

platform

*_____

weighing area into a weight reading

1

                        

the liquid crystal display (LCD). It is controlled

™___________

a

microprocessor and can therefore lJ

from ounces to grams at the touch of a button. The compact internal components also make it small and

li________________________________________

to store.

Reading 2

Comparing sources

When we read, we may wish to look at more than one source of information on a topic to:

1

     

get extra information

2

     

find a text we can understand

3

     

check points where texts disagree

In the tasks which follow, we will compare information from a diagram and a text.

Study this diagram of electronic scales and complete the notes below.

1

  

Load cell

between the platform and base

2

   

Strain gauge

bends with the load cell, stretching the wires, voltage falls in proportion to load

3

  

Circuit board

Converter function

Microprocessor

function

The electronic kitchen scale uses microchip technology. It is small, convenient to store, and more accurate than the traditional mechanical scale.

O

The load cell

is an aluminium alloy beam. When a load is placed on the platform, it causes the beam to bend very slightly in the middle where the holes are drilled, producing strain.

The strain gauge

consists of small wires through which a voltage flows. It is bonded to the load cell. When the load cell bends, the strain gauge bends with it. The heavier the load, the more it bends and the harder it is for the electricity to travel through the wires (for they are stretched), resulting in a lower voltage. The change in voltage is proportional to the load.

Strain gauge

Load cell

Scan this text to find information on the load cell, the strain gauge, and the circuit board. Note any information in the text which is new, i.e. additional or different to the information obtained from the diagram.

para

Electronic scales use a weighing device called a load cell                                  3

underneath the platform. The load cell, an aluminium alloy beam, eliminates the need for springs, cogs, or other moving parts which can wear, break, or cause inaccuracy in mechanical scales.

5

   

A strain gauge is bonded on the load cell. The strain gauge                               4

consists of a small piece of metal foil which detects any bending of the beam. A controlled input voltage is supplied to the strain gauge from a battery-powered circuit.

When a load is placed on the platform, it causes the load cell to                       5

10

    bend very slightly. This, in turn, causes a change in strain, which

triggers a change in the electrical resistance of the strain gauge.

As the resistance changes, so does the output voltage from the                        6

strain gauge. In short, the change in voltage across the strain gauge is proportional to the load on the platform.

15   The voltage from the gauge is small and has to be amplified and                      7

then converted into a digital signal. This signal is fed to a specially programmed microprocessor, which converts it into a weight reading. This is displayed on the LCD. The display will automatically switch off a few minutes after weighing is finished,

20

    thereby saving battery power.

Source: 'Inside out: Electronic scales'.

Education Guardian

Language study

Cause and effect, 1

Study these actions. What is the relationship between them?

1

    

A load is placed on the platform.

2

    

The load cell bends very slightly.

3

    

The strain gauge is stretched.

4

    

The electrical resistance increases.

In each case, the first action is the cause and the second action is the effect. We can link a cause and effect like this:

1+2

A load is placed on the platform, which

causes

the load cell

to

betid very slightly.

3+4

The strain gauge is stretched, which

causes

the electrical resistance

to

increase.

In these examples, both the cause and the effect are clauses

-

they contain a subject and a verb. Study this example:

Cause:     

The strain gauge is stretched.

Effect:     

An increase in electrical resistance.

The effect is a noun phrase. We can link cause and effect like this:

The strain gauge is stretched, which

causes

an increase in electrical resistance.

In Unit 22 we will study other ways to link a cause and an effect.

The diagram below is a cause and effect chain which explains how a strain gauge works. Each arrow shows a cause and effect link. Match these actions with the correct boxes in the diagram.

a An increase in resistance,

b   

A load is placed on the scale,

c A drop in voltage across the gauge,

d   

The load cell bends very slightly,

e They become longer and thinner,

f    

The strain gauge conductors stretch,

g The strain gauge bends.

7                                        6                                        5

Now practise linking each pair of actions, i.e. 1+2. 2+3. and so on.

Technical reading

Strain gauges

Read the text below to find the answers to these questions.

1

    

What principle do strain gauges operate on?

2

    

Why is it an advantage to have a long length of conductor formed into many rows in a strain gauge?

3

    

If you want to measure strain in a member, how do you position the strain gauge?

4

    

Why is an amplifier necessary?

5

    

Why is a dummy gauge included in the circuit?

6

             

 What is the function of VR2?

7

             

 Why would you adjust the output to exactly zero?

8

    

In the circuit shown, how is the amplifier output displayed?

Strain gauges

Strain gauges measure the amount of strain in a member. They work on the principle that the electrical resistance of a wire changes as it is stretched, becoming longer and thinner. The more it is stretched, the greater its resistance. Mathematically, this is written

5

   

as:

Resistance a *-en9th or R a

Area                     A

By arranging the wire in tightly packed rows, quite long lengths can be fitted on to a small pad (Fig. 1). Modern strain gauges are made not of wire, but by etching a pattern into metal foil which is stuck to a polyester backing (Fig. 2).

^

10

In use, a gauge is stuck on to the surface of the member being tested. Its active axis is fixed along the direction in which you want to measure the strain. Movements on the passive axis will have no real effect on it. The gauge must then be connected to an electronic circuit. Fig. 3 shows a block diagram of the complete circuit. The

15

resistance of the gauge is compared with the resistance of fixed value resistors in the circuit. Any differences in resistance are converted into voltage differences. These very small changes in voltage are amplified before being displayed.

Fig. 3 block diagram of the complete circuit

Wheatstone                         Amplifier                  Display

The final circuit, shown in Fig. 4, includes a dummy gauge. This

20

compensates for any changes in the resistance of the active gauge caused by temperature changes. The active and dummy gauges form part of the Wheatstone bridge. With no forces applied to the active gauge the output from this part of the circuit should be zero. When forces are applied, the resistance of the active gauge 25 changes so the output voltage to the amplifier changes. The

amplifier magnifies that change so that it can be clearly seen on the meter. The three variable resistors in the circuit each allow different adjustments to be made. VR1 allows you to 'balance' the bridge, getting the resistances exactly equal. VR2 allows you to adjust the

30

'gain' of the amplifier, in other words, how much the voltage is amplified. By adjusting VR3 the output can be adjusted to exactly zero before a load is applied to the member being tested.

In practice, strain gauges tend to be used in pairs or groups, often measuring the strain in various parts of a structure at the same

35

time. When used like this they are often linked to a computer rather than a series of display meters. The computer keeps a constant check on the outputs from each of the strain gauges, making sure that no part of the structure is being loaded beyond normal limits.

Source: P. Fowler and M. Horsley, 'Control Systems in the Home',

CDT: Technology

Robotics

Tuning-in

Task 1

Together, try to write a definition of a robot. Compare your answer with the definition of an industrial robot given on page 36 of the Answer Book.

Reading 1

Revising skills

In the tasks which follow, we will revise some of the reading skills you have studied.

Task 2

Positioning

commands

<

Computer with appropriate industrial interface

Feedback of positional information (only for closed loop control)

Fig.

7

The components of an industrial robot

Study this diagram which shows the components of an industrial robot. What do you think the functions of the three components shown are?

The manipulator

This is the bit which actually does the mechanical work, and in this case it is anthropomorphic (i.e. of human-like form), resembling an arm.

The power supply

For heavy-duty hydraulic or pneumatic machines this will be a 5 compressor. In smaller, lightweight versions which use electrical stepper motors rather than hydraulics or pneumatics, this would be omitted.

The computer

The controlling computer is fitted with appropriate interfaces. These may include digital inputs, digital outputs, ADCs (analogue-

10

to-digital converters), DACs (digital-to-analogue converters), or stepper motor control ports. These control the various compressors, stepper motors, and solenoids, and receive signals from the manipulator's sensors.

Task 4

1

2

3

4

Read the following text to find the answers to these questions.

What is the work volume of a manipulator?

W7hat is the work volume of a human?

Why is the work volume of a human greater than that of an industrial robot? What are degrees of freedom?

Work volume

Robots are multifunctional so an important design issue for the manipulator is its 'work volume': the volume of space into which it can be positioned. The greater the work volume, the more extensive the range of tasks it can be programmed to carry out.

5 As a human being, your work volume consists of all the places your hands can reach. Most industrial robots have a much more limited work volume because they are bolted to the floor. Even with the same limitation applied, however, the human body is a very flexible machine with a work volume described - very

10

approximately- by a cylinder about 2.2 m high with a radius of about 1.8 m and a domed top.

Degrees of freedom

In order to achieve flexibility of motion within a three-dimensional space, a robot manipulator needs to be able to move in at least three dimensions. The technical jargon is that it requires at least 15 three 'degrees of freedom'. Figs. 2 a-d show a number of the more common types of robot manipulator mechanisms. Each has the requisite three degrees of freedom, allowing either linear or rotational movement.

Study the text and accompanying diagram (Fig. 2a) below and note how the information has been transferred to Table 1.

Fig.

Type

Degrees of freedom

linear rotational

Work volume

2a

Cartesian or rectilinear

3

0

cube

?,b

2c

2d

Table 1

Task 5

Common types of manipulator

Fig. 2a is the simplest. Its three degrees of freedom are all linear and at right angles to each other, so they correspond to the three Cartesian co-ordinates. Driving it presents no mathematical difficulties, since each degree of freedom controls a single

1

  

Cartesian co-ordinate without affecting the others. Fairly obviously, the work volume of the Cartesian manipulator is a cube.

Fig. 2a Cartesian or rectilinear manipulator

Task 6

Work in groups of three. Your teacher will select a text for you. Read the text and diagram to complete your section of Table 1.

Text 1

The second type of manipulator, shown in Fig. 2b, is called a cylindrical manipulator because of the shape of its work volume. It has one rotational and two linear degrees of freedom. Because of the rotational aspect, however, the maths needed to position it

5

  

becomes more involved, which means that for a given response speed a faster processor is necessary.

Text 2

Fig. 2c shows the spherical manipulator which has two rotational and one linear degrees of freedom. The work volume is indeed a sphere, and once again the complexity of positioning the device increases.

Fig. 2c Spherical or polar manipulator

Text 3

The final type of manipulator has three rotational degrees of freedom. This is the most complex type to control, but it has increased flexibility. Fig. 2d shows this type of manipulator-the anthropomorphic arm. The work volume of a practical manipulator

5

  

of this form is shown in Fig. 3. You will notice that it is basically spherical but has missing portions due to the presence of the arm itself and because the rotations cannot achieve a full 360 degrees. The scallops on the inner surface are caused by constraints imposed by the joints.

Side view

Fig. 3 The work volume of an anthropomorphic manipulator

Task 7             

Now exchange information with the others in your group to complete the

table.

Task 8             

Complete the blanks in this text.

Mechanical wrist

It is worth pointing___________ that a human arm has far more freedom

________________ the minimum three degrees of freedom, giving very great

flexibility in terms _                   positioning, path taken, and angle of

approach. Even without a wrist, the redundant degrees of freedom of the

body would allow you to carry out most normal operations. Any

of the basic manipulators shown _________ _____ Figs. 2 a-d. on the other

. would be virtually useless as they stand. Although they could

get to any position, they __________           only approach objects from a single

angle.

8

                                                                                                                                                          

9

To take an___________ . removing a screw would be impossible

the manipulator could not align a screwdriver to tit the screw properly. Even if it was able to, it still would 10  be                                                  possible         to carry out the necessary

rotating action.

A wrist is therefore added to most basic manipulators to '1            the

required mechanical flexibility to 12                 real jobs. In  general, for total

flexibility the wrist itself requires three degrees of freedom, thereby bringing the grand total up to six. The '

[1]

common                         type of wrist has two bending

and one rotational degrees of freedom. Fig. 4 shows this type of mechanical wrist.

Language Study

Concession: even if and although

We can use

if

(see Unit 11) to link two statements like this:

1

     

The switch is on.

2

     

The lamp lights.

If the switch is on. the lamp lights.

When statement 1 is true, statement 2 is also true.

When statement 1 surprisingly has no effect on statement 2. we can use

even if

or

although.

For example:

A car is fitted with a seat belt warning light. The light operates under these conditions:

Seat occupied

Ignition

Belt

Light

Yes

On

Closed

Off

Yes

On

Open

On

Yes

Off

Closed

Off

No

Off

Closed

Off

Study these examples of normal and faulty operation:

Normal

If the seat is occupied, the ignition on and the belt closed, the light is

off.

Faulty

Even if the belt is closed, the light stays on.

Although the belt is closed, the light stays on.

Give other examples of normal and faulty operation of this circuit.

Technical reading

Stepper motors

Task 10

Read the text which follows to find the answers to these questions, then complete the table.

1

     

Why would you use a stepper motor to position the head of a disk drive unit?

2

     

Name two components that are present in other electric motor types but absent from stepper motors.

3

     

For accuracy in positioning, would you select a stepper motor with a large or a small step angle?

Type                                 Advantages                          Applications

Variable reluctance            No detent torque

High dynamic torque at low speed

Hybrid type                    Good speed/torque

characteristics

Can be made very small, very efficient

A stepper motor does not run in the same way as a normal DC motor, i.e. continuously rotating. Instead, it runs in a series of

10

measured steps. These steps are triggered by pulses from a

computer, each pulse making the motor turn either in a forward or a reverse direction by an exact interval, typically 1.8, 2.5, 3.75, 7.5, 15, or 30 degrees. Accuracy is within 3% to 5% of the last step.

r

Fig. 5b

Fig. 5a

The rotor in a stepper motor is constructed from several permanent 15 magnets with north and south poles. The stator is wound into a series of electromagnets, usually four, which can be switched on and off. Figs. 5a and b illustrate the operation of a permanent magnet-type stepper motor. When current is applied to the stator coils, it creates the pole arrangement shown in Fig. 5a. Poles 1 and

20

2 are north. Hence, the rotor south pole is attracted to both of them and settles in the mid position as shown. When the stator currents are changed to produce the pole arrangement shown in Fig. 5b, pole 1 has south polarity. This repels the rotor which moves to the new position as shown. Each polarity change on the stator causes 25 the rotor to move (in this case) 45 degrees.

Stepper motors can be divided into two groups. The first one works without a permanent magnet. The second one has a permanent magnet, usually located on the rotor.

Variable reluctance motors form the first group. As there is no 30 permanent magnet, the variable reluctance motor has practically no detent torque. The rotor spins freely and gives good acceleration and high speed if lightly loaded. Applications include micropositioning tables.

The second group comprise the permanent magnet motor, the 35 hybrid motor, and the disc magnet motor. The permanent magnet type offers high dynamic torque at low speed and large step angles. This is a low cost motor used extensively in low inertia applications such as computer peripherals and printers.

The hybrid type combines features of both types mentioned above. 40 It has good speed/torque characteristics and micro-stepping capability. Steps of 1.8 degrees are possible.

Disc magnet motors can be made very small and are very efficient. One of their first applications was in quartz-controlled watches.

Careers in engineering

Tuning-in

Task 1             

List some of the jobs in engineering. Combine your list with others in your

group.

Task 2             

Work in groups of three. A. B. and C. Scan your section of this text. A. B. or

C. How many of the jobs in the combined list you made in Task 1 are mentioned in your section?

Jobs in engineering

A

Professional engineers

may work as:

Design engineers:

They work as part of a team to create new products and extend the life of old products by updating them and finding new applications for them. Their aim is to build quality and

5

  

reliability into the design and to introduce new components and materials to make the product cheaper, lighter, or stronger.

Installation engineers

: They work on the customer's premises to install equipment produced by their company.

Production engineers:

They ensure that the production process is

10

efficient, that materials are handled safely and correctly, and that faults which occur in production are corrected. The design and development departments consult with them to ensure that any innovations proposed are practicable and cost-effective.                                                                                                                       ^

B

Just below the professional engineers are the

technician

15

engineers.

They require a detailed knowledge of a particular

technology - electrical, mechanical, electronic, etc. They may lead teams of engineering technicians. Technician engineers and engineering technicians may work as:

Test/Laboratory technicians:

They test samples of the materials

20

and of the productto ensure quality is maintained.

Installation and service technicians:

They ensure that equipment sold by the company is installed correctly and carry out preventative maintenance and essential repairs.

Production planning and control technicians

: They produce the 25 manufacturing instructions and organize the work of production so that it can be done as quickly, cheaply, and efficiently as possible.

Inspection technicians:

They check and ensure that incoming and outgoing components and products meet specifications.

Debug technicians:

They fault find, repair, and test equipment and 30 products down to component level.

Draughtsmen/women and designers:

They produce the drawings and design documents from which the product is manufactured.

C

The next grade are

craftsmen/women.

Their work is highly skilled and practical. Craftsmen and women may work as:

25

Toolmakers:

They make dies and moulding tools which are used to punch and form metal components and produce plastic components such as car bumpers.

Fitters:

They assemble components into larger products.

Maintenance fitters:

They repair machinery.

40

Welders:

They do specialized joining, fabricating, and repair work.

Electricians:

They wire and install electrical equipment.

Operators require fewer skills. Many operator jobs consist mainly of minding a machine, especially now that more and more processes are automated. However, some operators may have to

45

check components produced by their machines to ensure they are accurate. They may require training in the use of instruments such as micrometers, verniers, or simple 'go/no go' gauges.

Source: Adapted from S. Moss & A.S. Watts,

Careers in Engineering,

3rd edition

Task 3            

Combine answers with the others in your group. How many of the jobs listed

in Task 1 are mentioned in the whole text?

Task 4            

Who would be employed to:

1

    

test completed motors from a production line?

2

    

find out why a new electronics assembly does not work?

3

    

produce a mould for a car body part?

4

             

 see that the correct test equipment is available on a production line?

5

             

 find a cheaper way of manufacturing a crankshaft?

6

    

repair heating systems installed by their company?

7

    

see that a new product is safe to use?

8

    

commission a turbine in a power station?

Reading

Inferring from samples

In Task 5 below and in the Listening (Task 7), you are asked to infer from a small sample of text information which is not clearly stated. Use the clues in the samples and the knowledge you have gained from the text

Jobs in engineering.

Task 5

As a         group, try to identify the jobs of these workers from their statements.

1

               

We perform standard chemical and physical tests on samples, usually as a result of a complaint from inspectors on the production line. We are an important part of production. We have the authority to stop the line if we find something seriously wrong. It's interesting work, and we're able to

5

  

move around from test to test and chat. Sometimes, admittedly, the work

gets a bit repetitive.

2

               

All machinistscan be difficult. The older blokes especially don't like me telling them their work isn't good enough and instructing them to do it again. One or two of them seem to thinkthe inspector is always outto get

10

   them. I'm constantly havingtocalmthingsdown.

3

               

We measure up the components to see that they are the right size and shape, and we make any minor adjustments ourselves with hand tools or power tools. All along, parts will need adjusting slightly and you have to check things at each stage with measuring instruments and gauges. You

15

have to get a feel for it-clearances have to be just right. Otherwise things won't fit together.

4

               

Ifind myjob a very satisfying one. It's never easy to say exactly why one likes a job. I think the basic thing I get out of my profession at the moment is the creativity that is involved in design work. You start from square one

20 with a plain sheet of paper. You draw a component. You design

something and perhaps a few months later you can see the end product. And you get told whether or not your design works! I think it's that aspect that I find most satisfying.

5

               

I enjoy myjob. I really like doing the same thing every day-exactly the

25

same job. You knowwhatto lookforand howthingsshould be. You know howthe machine-orthe machines-run, when a machine is working properlyand when there is something wrong with it. I really like the routine. I don't have dreams of becoming a supervisor or anything like that. I'm just content running my machines.

6

          

30

Mycompany makes desalination equipment. Ittakesthesaltoutofsea

waterso it can be usedfordrinking and irrigation. A lot of ourcustomers are in the Middle East. I have to go there whenever new equipment is being set up to make sure it's properly installed and everything is running OK.

Source (quotations 1-5): T. May,

People at Work: Working at a light engineering plant

Speaking practice

Role play

Task 6

Work in pairs. A and B. Each of you has profiles of three workers in a light engineering plant which supplies car electrical components such as starter motors, fuel pumps, and alternators.

Play the part of one of these workers and be prepared to answer questions from your partner about your work. Your partner must try to identify your job from your replies.

In turn, find out about your partner.

Do not give your partner your job title until he or she has found out as much information as possible and has made a guess at your occupation. Try to find out:

1

     

Age

2

     

Education

3

     

Qualifications

4

          

 Nature of work

5

     

Who he/she is responsible to

6

     

What he/she feels about his/her work

Before you start, work out with your partner useful questions to obtain this information.

Student A: Your profile is on pages 179/80.

Student B: Your profile is on page 183.

Listening

Inferring from samples

Task 7

(SI Listen to these workers talking about their jobs. Try to match each extract to one of these jobs.

a Methods engineer b Systems analyst c Toolmaker

d Machine tool development fitter e Foreman/woman f Applications engineer

[1]

    running at 90 degrees to each other, they can be used to drive a pen an exact distance in all directions. In robotics, they are used to position manipulators exactly where required.