em ii, 2 engleza, - pdf

7/31/2019 EM II, 2 Engleza, - PDF

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Unit 1. DIESEL ENGINES

1.1 Types of engines

Slow-, medium- and high-speed Diesel engines

A Diesel engine is apropulsion plantin which the heat that is generatedby internal combustion of amixture offueland air is converted intopower.

There are slow speed -, medium speed - and high-speed Diesel engines. By "speed" is understood the

number ofrevolutions per minute (RPM) the shaftcan make.

The slow-speed Diesel engine is appliedin large vessels with large engine rooms. These engines are very

reliable, but take up a lot of space.

Slow-speed Diesel engines consume Heavy Fuel Oil (HFO), which is an inexpensive fuel. This type of fuel,

also called residual oil, is used in medium-speed Diesel engines, too. These engines are favoured in large

vessels, e.g. in ferries.

Compared to the slow-speed engine the medium-speed engine is more compact.

The medium-speed Diesel engine requires more maintenance.

High speed Diesel engines are used in small, highly manoeuvrable vessels.

The rated capacity ofsuch an engine is very high, but so is itsfuel consumption.

In-line engines and V-engines

Diesel engines may have cylinders that are

placed "in line" or in a bevel (oblique)

position.

Compared to the in-line engine the

advantages of the V-engine are obvious: a V-

engine requires only one crankshaftand

takes up less space.

Therefore the V-engine is very suited to beinstalled in engine rooms of limited size,

contrary to the in-line engine, which cannot

be used in small engine rooms due to its

height.

The in-line engine is not as costly as the V-

engine. The construction of the in-line

engine is simple, which makes the

maintenance and overhauling relatively easy

and cheap.

V-engine Line engine


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Trunk engines and Crosshead engines

As to the construction of Diesel engines we

distinguish two main types: the trunk engine

and the crosshead engine.

In a trunk engine thepiston pin and crank

pin are directly connected to each other by

the connecting rod. Trunk engines are of

compacted build and are mostly medium

speed- or high-speed engines. Compared to

the crosshead engines they do require more

maintenance.

The crosshead engine is taller because of the

crosshead andpiston rod, which require

more space. These engines are mainly used

in large vessels. The crosshead serves as a

hinging connection between piston rod and

connecting rod.

Crosshead guide shoes and crosshead guides absorb the forces onto the crosshead when the piston goes

down. With a direct-acting (or direct-reversible) crosshead engine maintenance costs can be kept to a

minimum because there is no reversing gear. The crosshead engine is reputed to be very reliable, but is

considered to be more costly compared to the trunk engine.

Two-stroke engines and four-stroke engines

Thepiston in a cylindermakes a reciprocating motion - it goes up and down.

The up and down motions of a piston are called strokes.

The number of strokes of a piston that form a cycle in a cylinder is two or four.

The two-stroke principle is applied in slow speed engines.

Compared with the four-stroke engine, its advantage is that each cylinder is capable of generating more

power, because the number ofpower strokes by the piston is twice as many as with the four-stroke cycle

at the same crankshaft speed.

The disadvantage of the two-stroke engine is that, unlike with the four-stroke engine, its effective power

is limiteddue to the fact that its ability to burn fuel is less than in a four-stroke engine.

This latter engine is used in smaller vessels with medium-speed or high-speed engines.

1.2 The working of engines

The working of a two-stroke engine

The two-stroke cycle begins when the piston is in its Bottom Dead Centre (BDC).Air enters the cylinder through the inlet ports.

During the compression stroke the air in the cylinder is compressed while the piston travels upwards.

Fuel is admitted to the cylinder at the end of this stroke.

The mixture of air and fuel ignites spontaneously due to the high compression and consequent high

temperature in the cylinder.

During the power stroke the piston is pushed down by the "explosion" of the mixture in the cylinder.

The reciprocating piston and connecting rod will cause the crankshaft to rotate.

Now the camshaft is actuated, so that the rocking lever can open the valve (a pushrod may be inserted

as a distance piece between camshaft and rocking lever).

Thus, at the end of the power stroke, the exhaust valves are opened, allowing the exhaust gases to

escape into the exhaust gas manifold, after which the remaining exhaust gases are removed out of thecylinder by scavenging air. The scavenging system that is most widely employed nowadays is the uniflow

scavenging system, because it removes almost all the exhaust gases out of the cylinder.

Cross scavenging- or loop scavenging systems are not effective enough and will leave behind small

Trunk engine Crosshead engine


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amounts of gases that will form carbon deposits in the cylinder.

Before a new cycle is started, the exhaust valve is closed by the exhaust valve spring or by a hydraulic

system.

The working of a four-stroke engine

Four-stroke engines are usually medium speed- or high-speed engines.

The four-stroke cycle begins when the piston is in its Top Dead Centre (TDC).

During the inlet stroke (also called suction stroke or air-induction stroke) the inlet valve is opened and air is

drawn into the cylinder (A).

During the compression stroke, when the piston has just passed its Bottom Dead Centre (BDC), the inlet

valve is closed and the air in the cylinder is compressed by the piston going up (B).

At the end of this stroke the fuel is injected by the atomizer. The nozzle on the atomizer divides the fuel

into very small particles, so that it can mix with the air in the cylinder.

During the power stroke the mixture of air and fuel is burnt by the high temperature in the cylinder.

The "explosion" that follows will move the piston down (C). The reciprocating piston and connecting rod

will cause the crankshaft to start rotating, which will actuate the camshaft. Now the rocking lever willactuate the valve mechanism.

In the four-stroke cycle the exhaust gases in the cylinder are removed by the piston itself. During this

exhaust stroke the exhaust valve is opened, allowing the exhaust gases to escape from the cylinder (D).

A B C D

Cross scavenging Loop scavenging Uniflow

scavenging


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The valve mechanism

Valves are opened by rocking levers (rocker arms)

(1) and are mostly closed by springs.

The rotating crankshaftactuates the camshaft {2)

by means of gearwheels or chaindrive.

The campeak, which is fixed to the rotating

camshaft, actuates the rocking lever.If apushrod (3) has been inserted between

camshaft and rocking lever, the rocking lever will

be actuated by this latter rod and will open the

valve (4).

The mechanism of an air-induction valve, exhaust

valve or starting-air valve consists of the valve

spring (which closes the valve), the valve stem,

the valve disc and valve seat.

Reversing the engine

The slow speed Diesel engine is mostly a direct reversible - or direct acting - engine.

This means that the shaft is directly connected to the engine. In order to go from ahead to astern or

astern to ahead - we must stop the engine first and then reverse it. With a reversing gear the engine can

be reversed without having to stop the engine first. It is used in small vessels.

Vessels that require to be highly manoeuvrable, with variable rated capacities, are equippedwith

Controllable Pitch Propellers.

By pitch is understood the distance travelledafter one revolution of the propeller, but it also indicates

the blade-angle of the propeller.

A Controllable Pitch Propeller, or C.P.R, is fitted with adjustable blades. These blades can be put in

various positions, whereby the angle of the blades determines the speed at which the vessel willproceed.In other words: the propeller-pitch can be controlledby adjusting the blades. The blades can even be put

in such a position that the sailing direction can be altered from ahead to astern.

The advantage of the C.P.P. is that the number of revolutions per minute (RPM) will remain constant, in

spite of an increase or reduction of sailing-speed. The engine will have a longer life, because it does not

suffer from extensive wear that is normally caused by a constantly changing RPM.

C.P.P. with adjustable blades Pitch


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The Shaft

The shaft consists of the propeller shaft, the intermediate shaft and the crankshaft.

They are connected to each other by means offlanges.

The end of the propeller shaft is conical (tapered) to make it easier to mount the propeller.

The intermediate shaft is a distance piece between the crank shaft and the propeller shaft.

Bearing-blocks and thrust blocks support the shaft. Thrust blocks take up the propulsion forces of the

screw and conveythem to the hull of the ship.

Self-assessment Test

Insert the following words in the right places:

internal combustion engine , fuel, heat of compression, ,

spark plug, thermal efficiency, due to, compression ratio,

ignition, two stroke, gas engine, combustion chamber,

petrol engine, Rudolf Diesel, four stroke

A diesel engine is an ... that uses the ... to initiate ... to burn the ..., which is injected into

the .... This is in contrast to spark-ignition engines such as a ... (gasoline engine) or ...

(using a gaseous fuel as opposed to gasoline), which uses a ... to ignite an air-fuel mixture.

The engine was developed by ... in 1893.

The diesel engine has the highest ... of any regular internal or external combustion engine

... its very high .... Low-speed Diesel engines (as used in ships and other applications where

overall engine weight is relatively unimportant) often have a thermal efficiency which

exceeds 50 percent.

Diesel engines are manufactured in ... and ... versions.

Progress test

Look at the text on engines and try to find the type described below

Also known as ..., the largest diesel engines are primarily used to power ships. These

extremely large two-stroke engines have power outputs up to approximately 85 MW (114,000

hp), operate in the range from approximately 60 to 200 rpm and are up to 15 m (50 ft) tall,

and can weigh over 2,000 short tons (1,800 t). They typically use direct injection running oncheap low-grade heavy fuel, also known asBunker Cfuel, which requires heating in the ship

for tanking and before injection due to the fuel's high viscosity. The heat for fuel heating is

often provided by waste heat recovery boilers located in the exhaust ducting of the engine,

which produce the steam required for fuel heating. Provided the heavy fuel system is kept

warm and circulating, engines can be started and stopped on heavy fuel.
http://en.wikipedia.org/wiki/Internal_combustion_enginehttp://en.wikipedia.org/wiki/Diesel_fuelhttp://en.wikipedia.org/wiki/Heat_of_compressionhttp://en.wikipedia.org/wiki/Spark_plughttp://en.wikipedia.org/wiki/Thermal_efficiencyhttp://en.wikipedia.org/wiki/Compression_ratiohttp://en.wikipedia.org/wiki/Combustionhttp://en.wikipedia.org/wiki/Two_strokehttp://en.wikipedia.org/wiki/Gas_enginehttp://en.wikipedia.org/wiki/Combustion_chamberhttp://en.wikipedia.org/wiki/Petrol_enginehttp://en.wikipedia.org/wiki/Rudolf_Dieselhttp://en.wikipedia.org/wiki/Four_strokehttp://en.wikipedia.org/wiki/Internal_combustionhttp://en.wikipedia.org/wiki/External_combustionhttp://en.wikipedia.org/wiki/Shiphttp://en.wikipedia.org/wiki/Viscosityhttp://en.wikipedia.org/wiki/Viscosityhttp://en.wikipedia.org/wiki/Shiphttp://en.wikipedia.org/wiki/External_combustionhttp://en.wikipedia.org/wiki/Internal_combustionhttp://en.wikipedia.org/wiki/Four_strokehttp://en.wikipedia.org/wiki/Rudolf_Dieselhttp://en.wikipedia.org/wiki/Petrol_enginehttp://en.wikipedia.org/wiki/Combustion_chamberhttp://en.wikipedia.org/wiki/Gas_enginehttp://en.wikipedia.org/wiki/Two_strokehttp://en.wikipedia.org/wiki/Combustionhttp://en.wikipedia.org/wiki/Compression_ratiohttp://en.wikipedia.org/wiki/Thermal_efficiencyhttp://en.wikipedia.org/wiki/Spark_plughttp://en.wikipedia.org/wiki/Heat_of_compressionhttp://en.wikipedia.org/wiki/Diesel_fuelhttp://en.wikipedia.org/wiki/Internal_combustion_engine


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Unit 2 DIESEL ENGINES: TASKS

2.1 IdiomsThe italicizedwords in the text are given below in alphabetical order.

Find out what they mean as they appear in the text and learn them by heart.

actuate compression stroke direct acting

adjustable blades connect direct reversible

admit connecting rod disadvantage

advantage consume distance travelled

air induction stroke control distance piece

alter Controllable Pitch Propeller distinguish

angle convey effective power

apply crank employ

atomizer crankshaft equipped with

bevel crankweb exhaust valve

Bottom Dead Centre cross scavenging exhaust gases

campeak crosshead engine flange

camshaft cylinder fuel consumption

chain decrease gearwheel

compression determine generate

ignite power stroke rotary motion

increase power sailing direction


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insert propulsion plant scavenging

internal combustion pushrod shaft

limited rated capacity spontaneously

loop scavenging reciprocating motion spring

maintenance reduce stroke

manifold reliable suction

mixture remain thus

nozzle remove Top Dead Centre

oblique reverse uniflow scavenging

overhaul reversing gear valve

pin revolution valve seat

piston rocker arm

piston rod rocking lever

2.2 Application, advantages and disadvantages

Fill in what the application(s) of the various types of engine are and compare the engines with regard to

their advantage(s) and disadvantage(s).

Types of engines Application(s) Advantage(s) Disadvantage(s)

Slow-speed engine

Medium-speed engine

High-speed engine


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V-Engine

In-line engine

Trunk engine

Crosshead engine

Two-stroke engine

Four-stroke engine

2.3 Sequence of events

2.3.1 Indicate by means of the letters A / N the sequence of events in a two-stroke engine.

Start with the letter A (Piston is in its BDC).

1 2 3 4 5 6 7 8 9 10 11 12 13 14

A K M

A - Piston is in its BDC.

B - The exhaust gases are passed to the exhaust manifold.

C - The crank is actuated.

D - The camshaft actuates the push rod.

E - The fuel / air mixture is ignited.

F - Cylinder is filled with air.

G - The reciprocating motion changes into a rotary motion.

H - The rocking lever is actuated by the pushrod.

I - Scavenging air removes exhaust gases.

J - The piston goes up and compresses the air in the cylinder.

K - The piston and connecting rod are pushed down.L - The crankshaft actuates the camshaft.

M - The exhaust valves are opened.

N - Fuel is admitted during the compression stroke.


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2.3.2 Sequence of events

Indicate by means of the letters A / J the sequence of events in a four-stroke engine.

1 2 3 4 5 6 7 8 9 10

A

A - Piston is in its TDC.

B - All the valves are closed; compression of the air in the cylinder.

C - Piston removes the exhaust gases from the cylinder.

D - Explosion forces the piston down.

E - At the end of the compression stroke the atomiser sprays fuel through the nozzle.

F - The cylinder is filled with air.

G - Power stroke, during which the mixture is ignited.

H - The inlet valve is opened during the air-induction stroke.

I - Piston passes its BDC.J - Piston passes its BDC again

2.4 Engine parts

Indicate the engine parts


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Read the details, look at the picture and name this stroke

Just before TDC fuel is injected into the cylinder by the fuel injector. The fuel isatomised into tiny droplets. Because they are very small these droplets heat up

very quickly and start to burn as the piston passes over TDC. The expanding gasfrom the fuel burning in the oxygen forces the piston down the cylinder, turning

the crankshaft.

Progress test Fill in the blanks with the following words:

sounds/ watchkeepers /excuse/ warn /diagnose /

investigated /sounding /cause/ noise/ do/

Alarms are installed to ... the operator that all is not well with the machinery. If an alarm ...,

then the cause must be ... and rectified. Do not use the ... that "the alarm is faulty" as the first

reason for it ... in the first place. As well as alarms, the ... sense of hearing, smell and touch

must be used to ... faults. If an unusual ... is heard, ... not ignore it; investigate the ....

A: cylinder

B: cylinder liner

C: cylinder jacket

D: piston

E: piston rings

F: inlet ports

G: manifold

H: piston rod

I: crosshead

J: guides + guide shoes

K: connecting rod

L: crankpin

M: crank

N: crankshaft

0: chaindrive

P: camshaft

Q: campeak

R: pushrod

S: rocking lever

T: exhaust valve

U: exhaust valve spring

V: scavenging ports


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Unit 3 THE FUEL SYSTEM

3.1 Introduction

Diesel engines consume Heavy Fuel Oil (HFO) or Marine Diesel Oil (MDO, or DO).The lattertype of fuel may be used when the vessel is manoeuvring.

HFO is merely a residue that remains after the refinery process ofcrude oil. It is made suitable

for driving Diesel engines by adding certainflammable substances, such as MDO.

Combustion of a fuel is the chemical combination ofcarbon and hydrogen with oxygen. The

quality of a fuel is expressed by the word "grade", which basically indicates how well a fuel

will burn in the cylinders.

HFO is a low-grade oil and has a high viscosity. MDO is a high-grade fuel of lower viscosity. It

is thinner than HFO, and therefore it will flow more easily.

Any fuel whose grade lies between HFO and DO is calledIntermediate Fuel Oil (IFO).

When assessing the quality of a fuel, one must take into consideration a large number of

standardproperties of fuels that will determine its grade.

The most important properties are:

Specific Gravity (density)

The specific gravity of a fuel indicates the density of the fuel compared to that of water.

One hundred kilograms of water will take up less space than one hundred kilograms of oil.

Therefore the sg-indication of a fuel is essential information for when the vessel is taking

bunkers. The specific gravity is always measured at a temperature of 15 degrees Centigrade.

Viscosity

The kinematic viscosity indicates the resistance a liquidwill experience while flowing.

A high viscosity grade indicates that afluidwill resist a tendency to flow.

A low viscosity grade indicates that a fluid will flow very easily.

Bypreheating the fuel before it is entered into the fuel system the viscosity will be lowered.

Viscosity is most commonly measured in centistokes (cSt).

The cSt-measurement is related to the amount of time it will take a specific amount of liquid to

flow through a calibrated orifice.

Average fuel oil requires a viscosity grade of at the most 800 cSt to be able to be pumped from

the bunker tanks into the system.

Flash Point

Theflash pointof a fuel indicates the lowest temperature at which the vapourabove a liquid in

closed surroundings can be ignitedby means of a spark.

Adequate and accessible information concerning the flash points of all the flammable liquids

that are carried on board will greatly contribute to safety aboard vessels.

Pour Point

Thepour pointof a liquid indicates the lowest temperature at which a fuel can still be handled.

It is important in the process oftransferring fuel from shore-based tanks or fuel-boat into thebunkers aboard the ship.


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Specific Energy

The specific energy indicates the calorific value of one kilogram of fuel - in other words: it

indicates the quantity of heat produced by the complete combustion of one kg of fuel.

Solubility

The ability of a fuel to mix with another fuel, which may result in a fuel of higher quality, isindicated by the solubility-factor.

Cetane-number

The cetane number indicates the ease with which a mixture of fuel and air will ignite.

The ignition-quality of a fuel will dependupon the fuel/air-ratio, the temperature and pressure

of the mixture, the density of the fuel and the ambient temperature.

Sediment

Matters such as grit, clay and sand are non-organic substances that occur in a fuel. Thesesediments can be removed from the fuel by settlement, centrifugation and filtration, depending

on particle size and density.

Methods to ascertain the amount of sediments and water in a fuel are called "Sediment by

extraction" and "Water and sediment by centrifuge".

Stability

A fuel can be called stable when, even after a long period ofstorage, no heavy components

(sediments,) will be separated and settle on the bottom of the tank.

Carbon-Residue

The carbon-residue indication is used to assess the amount of carbon deposit a fuel will cause in

nozzles, on piston rings, pistons, exhaust valves and exhaust gas turbines.

Cloud Point

The cloud point of a fuel is defined as the temperature at which a clear transparent fuel (DMX)

will become hazy or cloudy due to the formation of wax crystals.

Wax crystals, causing engine failure, will be formed in a fuel with a high cloud point when the

engine is started at a low ambient temperature.

Ash

Ash in a fuel refers to the amount of non-organic non-combustible materials present in a fuel,

such as vanadium, sodium, calcium, zinc, lead, iron, nickel, etc.

Distillate fuels (Marine Diesel Oils) should have negligible amounts of ash-forming

components.

Residual fuels, however, contain higher amounts of ash-forming components.

Sulphur

Residual oils will always contain a certain amount of sulphur. The use of high-sulphur-fuels inDiesel engines will cause severe corrosion.


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3.2 Marine fuel oil standards

In order to be able to assess the quality of marine fuels, the international ISO-standard is used.

Heavy Fuel Oils

The abbreviation"RM stands for Residual Marine Oil.

Corresponding to the viscosity grade of a fuel, there are now six main groups of fuels, indicated

by the numbers 10, 15, 25, 35, 45 and 55. These groups are sub-divided again into groups that

are indicated by the letters A, B, C, D, E, F, G, H, K and L. These letters indicate the quality of

the fuel, ranging from high quality fuels ("A") to low quality fuels ("L").

Marine Diesel Oils

There are 4 MDO-grades, indicated by the letters X, A, B and C.

THE FUEL SYSTEM

The easiest manner of bunkering - taking the fuels on board - is by gravity, for which a

difference in level between the shore-based tanks and the bunker tanks on board is required.

Bunkering underpressure is done by pumps. This standard method goes much quicker than

bunkering by gravity. However, there is more risk ofspilling.

Heavy fuel oil (HFO) is stored in the bunker tanks - or bunkers. In the bunker tank the HFO ispreheated before it is pumped up.

From the bunker tank the preheated HFO is first passed to the settling tanks, where the fuel is

constantly heated to lower the viscosity-grade and thus quicken the separation of fuel from

water and impurities.

Before the fuel is passed to theDaily Service Tanks the water and impurities are drainedoff

from the settling tank, after which the process of preheating and separation is continued by a

heater, apurifierand often a clarifier. The former separates water and impurities from the fuel;

the latter separates impurities from the fuel.

In most fuel systems the settling tanks and daily service tanks are so called gravity tanks.


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Usually two daily service tanks have been installed, so that one tank can be filled while the

other is being used. Each tank has the capacity toprovide the engine with fuel for 24 hours.

The low-pressure fuel pump (or "booster pump") now draws the HFO from the daily service

tank and passes it to the high-pressure fuel pumps in the engine. Between the booster pump and

the high-pressure fuel pumps the fuel is first preheated and filtered by a strainer.

A viscosity controller, or viscosity regulator, checks the viscosity of the fuel. When the

viscosity is too high, the fuel will have to be heated, so that it will become thinner and suited to

be entered into the engine.

Diesel oil (MDO) may be used when the vessel is manoeuvring. It is stored in the DO bunker

tank.

After the DO has been pumped up from the bunker tank, the fuel will pass through a purifier.

From the purifier the DO enters the MDO service tank.

When changing from HFO to DO (or vice versa), it should be avoided to make this transition

too abrupt.

A mixing tank to mix the HFO with the MDO first will ensure a gradual transition from HFO to

DO. In this mixing tank the hot fuel fumes caused by the preheating of the fuel will accumulate.

The mixing tank may be fitted with an air vent(or "breather'), through which the fuelfumes

that have accumulatedcan escape. That is why the mixing tank is also called "vent tank".

To make it even more complicated: this tank can also be referred to as "buffer tank", or

"circulating tank", because it holds a quantity of fuel that will serve as a "buffer" that can be

circulated and led to the engine.

abbreviation component gravity

accumulate consideration hydrogen

add consume ignite

agent crude oil ignition

air vent Daily Service Tank impurities

ambient temperature depend upon intermediate fuel

3.3 Idioms


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assess determine latter

booster pump drain off level

breather experience liquefied

calibrated flammable liquid

calorific value flash point measure

carbon deposit fluid nozzle

carbonic acid fumes orifice

clarifier grade oxygen

combustion gradual piston ring

pour point resist storage

preheat resistance strainer

pressure settle sulphur

properties shore-based tank surroundings

provide sodium transfer

purifier solubility transition

quantity spark vapour

ratio specific gravity viscosity

residue spilling viscosity controller


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When a coordinating conjunction connects two independent clauses, it is often (but not always)

accompanied by a comma:

John wants to become a deck officer, but he has had trouble meeting the academic

requirements.

When the two independent clauses connected by a coordinating conjunction are nicely balanced

or brief, many writers will omit the comma:

John is good at sciences but his English is not so good.

The comma is always correct when used to separate two independent clauses connected by a

coordinating conjunction.

A comma is also correct when andis used to attach the last item of a serial list, although many

writers (especially in newspapers) will omit that final comma:

John spent his summer studying grammar, writing, and reading comprehension.

When a coordinating conjunction is used to connect all the elements in a series, a comma is not

used:

Deck and engineer and electrician cadets are taking an English test.

A comma is also used with butwhen expressing a contrast:

This is a useful rule, but difficult to remember.

In most of their other roles as joiners (other than joining independent clauses, that is),

coordinating conjunctions can join two sentence elements without the help of a comma.

Self-assessment TestGive the right answer

1. Why did the king draw straight lines?

Because he was the pencil.

Because he was the rubber.

Because he was the ruler.

Because he was the straightener.

2. A: Waiter! Whats this in my bowl? B: ... A: I dont care what its been. I want to know what it is

now.

Its tomato soup, madam.

Its leek soup, madam.

Its bean soup, madam.

Its carrot soup, madam.

3.4 Coordinating conjunctions - punctuation
http://ccc.commnet.edu/grammar/clauses.htmhttp://ccc.commnet.edu/grammar/clauses.htm


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3. How does Moose begin a letter to his cousin?

Dear Deer /Dier Deer / Dear Deir / Deer Dear

4. Why were the elephants thrown out of the swimming pool?

Because they couldnt keep their ears up.

Because they couldnt keep their trunks up.

Because they couldnt keep their shorts up.

Because they couldnt keep their branches up.

5. What is a large animal with thick fur but no clothes on?Bare bear / Baer bear / Bear bare / Bare beer

Progress test

Indicate by means of the letters A / N the sequence of events during the time that the engine is

run on HFO (on open sea) and MDO (vessel is about to enter the port of Rotterdam).

AA - Preheated HFO is pumped up from the bunker tank.

B - The low pressure fuel pump pumps the HFO to a heater.

C - A purifier separates water and impurities from the fuel.

D - HFO is stored in the Daily Service Tank.

E - The viscosity of the heavy fuel oil is checked.

F - HFO and DO are led to the mixing tank for a gradual transition.

G - The HFO is preheated.

H - The supply of HFO is stopped.

I - The HFO is filtered before it is led to the high pressure fuel pumps.

J - Diesel oil is led to the high pressure fuel pumps in the engine.

K - HFO is led to the settling tank.L - Water and impurities are separated in the tank.

M - Diesel oil is led to the Diesel oil service tank.

N - Diesel oil is passed through a separator.


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Unit 4 LUBRICATION4.1 Introduction

An engine contains many moving parts, and to prevent any wear or damage as a result of friction, a

lubricantmust be appliedbetween these parts.

Lubricating oilhas many properties that have positive influences on the engine.One of its properties is its cooling-ability - the lube oil will carry away the heat that is generatedby the

friction between the various moving parts.

Furthermore, lubricating oil has the ability to prevent impurities from clogging together.

Instead, these particles will suspend and float on the surface of the liquid. This makes it easy to remove

them. The lube oil will also serve as an anti-corrosive agent - it will prevent the forming of rust.

The thin oil layer (oroil film) will sea/ off pits and scratches in cylinder walls. This will prevent a "blow

by" - leaking of exhaust gases through the cylinder-liner.

Finally, the thickness of the lubricant will reduce engine-noise considerably.

This thickness of lubricating oil is indicated by the viscosity grade. When a liquid is very "viscous'it will

resist the tendency to flow. A liquidof low viscosity, such as water, will flow very easily through pumps

and piping systems.When the engine-temperature rises, the viscosity of the oil will be reduced andthe oil will become less

effective. That is why it is very important to indicate the viscosity grade of a lubricant at higher

temperatures.

The lube oil is stored in the drain tank.

This oil sump, as it is also called, is often

integratedin the double bottom.

"Ullage"is the space between the surface of

the oil and the top of the tank and will allow

for the expansion of the oil when the engine

gets hot. The air in this space will also

expand, and to prevent the lubricant from

being forced down by the pressure that will

arise form the expansion of hot air, the

drain tank is fitted with an airi/en/.This

air vent, or breather, serves as an escape for

the hotfumes that have accumulatedin the

drain tank. In aforced lubricating system the

lube oil is pumped from the drain tank to

sounding rod the distribution branches in the

engine and to the shafting. Before it is

entered into the engine the used oil must first be filtered and cooled by seawater or fresh water.

Lubrication in a crosshead engine

In a crosshead engine oil bores lead the oil through the crankshaft, crankwebs and crankpins. From

there the oil passes from the main bearing to the crank, connecting rod, crosshead, crosshead guide

shoes and crosshead guides.

Lubrication in a trunk engine

The rotating crank causes an oil mist when it throws up the lube oil.

The oil passes through the main lube-oil supply line to the crankshaft-bearings and camshaft- bearings,

after which the used oil is passed through strainers before it returns to the drain tank.

Before the lubricating oil is entered into the system again, it must bepurified byanother strainer in the

Lubricating arrangement of a Diesel Engine.

breather pipe


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drain tank. The oil-levelin the drain tank can be measuredwith a sounding rodand read from a level

gauge.

4.2 Idioms

ability crankweb level gauge

accumulate crosshead guide level

agent crosshead guide shoes liquid

air vent decrease lube oil

allow for distribution branches lubricant

anti-corrosive escape lubricate

apply expand lubricating oil

bearing forced lubrication lubrication

breather friction main

camshaft bearing fumes measure

connecting rod generate noise reduction

contain grade oil bore

crank impurities oil sump

crankpin integrate oil mist

crankshaft layer properties

purify serve supply line

reduce shafting ullage space


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reduction sounding rod viscous

remove strainer wear

seal sufficiently worn

4.3 Subject-Verb Inversion

The normal English order of subject-verb-completer is disturbed only occasionally but under

several circumstances. The most important of these are as follows (subjects in blue):

1. In questions (routinely): "Have you eaten breakfast yet?" "Are you ready?"

2. Inexpletive constructions: "There were four basic causes of the Civil War." "Here is the

book."

3. In attributing speech (occasionally, but optionally): "'Help me!' cried Farmer Brown."

4. To give prominence or focus to a particular word or phrase by putting the predicate in the

initial position: "Even more important is the chapter dealing with ordnance."

5. When a sentence begins with an adverb or an adverbial phrase or clause: "Seldom has so

much been owed by so many to so few."

6. In negative constructions: "I don't believe a word she says, nor does my brother. Come to

think of it, neither does her father."

7. Afterso: "I believe her; so does my brother."

Self-assessment Test Make sentences by beginning with the words in brackets

1. I do not travel to Miami with my wife. (under no circumstances)

2. We have done bungee jumping. (never)

3. He seldom leaves his cabin. (Seldom)

4. If I were a millionaire, I would travel all over Europe. (Were)

5. If he hadnt wasted so much money on buying lottery tickets, he could have payed his bills.

(Had)

6. His manner was so absurd that everyone laughed at him. (So)

Progress test Choose the right answer:

1. The thickness of the lubricant will ... engine-noise considerably.

A. increase; B. reduce; C. amplify; D. determine

2. The lube oil carries away the heat generated by the ... between moving parts.

A. contact; B. misunderstanding; C. friction; D. corrosion.

3. The lube oil is an anti-corrosive agent - it prevents the forming of ....

A. lust; B. vapour; C. oil film; D. rust.

4. This thickness of lubricating oil is indicated by the viscosity ....

A. grade; B. angle; C. degree; D. amplitude.

5. When the engine-temperature ..., the viscosity of the oil will be reducedA. go up; B. go down; C. rises; D. decrease.
http://ccc.commnet.edu/grammar/concise.htm#expletivehttp://ccc.commnet.edu/grammar/concise.htm#expletivehttp://ccc.commnet.edu/grammar/concise.htm#expletivehttp://ccc.commnet.edu/grammar/concise.htm#expletive


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Unit 5 COOLING THE ENGINE5.1 Introduction

Due to the very high temperatures caused by the combustion of the fuel and thefriction betweenthe various moving engine parts, cooling of the engine is necessary to reduce wear and thermal

deformation as a consequence of the constant expansion and shrinking of these engine parts.

The engine parts that require cooling are:

- the cylinder (liners and covers): the cylinder is cooled by injecting the coolant between the

cylinder linerand the cylinderjacket. The most common coolant is fresh water.

- thepiston: when the piston goes up and down, the coolant (oil) will enter through thepiston rod

bore and will leave through the inside return pipe;

- exhaust valves and housings',

- fuel valves, especially around the atomisers;

- the housing of the exhaust gas turbines;

- crosshead guides and crosshead guide shoes.

5.2 Coolants

The coolants that are used in the cooling process are: seawater,fresh water, oil and air.

The advantages ofseawater as a coolant are: it is free of charge and can absorb a lot of heat.

Furthermore, a seawater cooling-system can be made very simple since the used seawater can be

dischargedinto the sea.

The disadvantages of seawater are obvious: it contains a lot of minerals that will stick to all

heated surfaces and form a deposit. This "scale", as it is called, must be removed, because it willform an insulation that will prevent exchange of heat.

Seawater will also cause corrosion to the engine parts and piping.

We do use seawater as a cooling medium in an indirect cooling process ("cooling the coolant").

Before the coolant will be circulated through the engine again, it is cooled with seawater by a heat

exchanger.

The seawater enters the ship through seawater inlets.

These inlets are fitted with sea-chests that filter the water before it is led to the heat exchangers.

Fresh water has the ability to absorb much heat and will hardly cause any forming of scale.

Compared to seawater, however, fresh water is very costly. Therefore it is only used in closed

circuits, so that it can be reused.

Oil as a coolant has a lot of advantages.

Apart from cooling, it will reduce engine-noise, because the thickness of the oil will serve as a

"muffler". Oil is anti-corrosive and has apurifying function (unwanted particles and impurities

will be carried away by the oil).

Another advantage is that the oil will form a thin sealing-layer that will seal off pits and scratches.

And, most importantly, oil has a lubricating function, which, in an engine with numerous moving

parts, is a very important aspect.

However, the amount of absorbed heat per cubic metre of oil is less than that of water.

Oil may also cause carbon depositon the surfaces that need cooling.


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Air has the advantage of being free of charge. However, its disadvantage is the enormous amount

of air needed to cool a small area or surface.

Comprehension exercise

Answer the questions:1. Why is the cooling of the engine necessary?

2. What engine parts require cooling?

3. What coolants are used in mrine engines?

4. Compare oil and air as coolants.

5.3 Tasks: idioms, advantages and disadvantages

The italicized words in the text are given below in alphabetical order.


advantage due to necessary

apply exhaust valve piston rod bore

area expansion purify

atomiser fresh water reduce

carbon deposit friction remove

combustion fuel valve require

common coolant guide reuse

consequence guide shoe scale

cooling medium heat exchange sea chest

corrosion heat exchanger sealing layer

cylinder cover housing shrink


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cylinder liner impurities thermal

deformation inside return pipe wear

deposit insulation wear resistant

disadvantage jacket worn

discharge muffler

2) Advantage and disadvantage

Fill in the advantage(s) and disadvantages(s) of the various coolants:

Cooling Medium Advantage(s) Disadvantage(s)

Seawater

Fresh water

Oil

Air


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Which of the following characteristics should an ideal coolant have? Tick them.

high thermal capacity

high viscositylow-cost

non-toxic

chemically inert

causing corrosion

Progress test

Fill each gap with a word from the list

to, either, refrigerant, or, phase change, low,

efficiency, commonly, its, latent heat

The coolant can ... keep ... phase and stay liquid or gaseous, ... can undergo a ..., with the

... adding ... the cooling .... The latter, when used to achieve ... temperatures, is more ...

known as ....
http://en.wikipedia.org/wiki/Thermal_capacityhttp://en.wikipedia.org/wiki/Viscosityhttp://en.wikipedia.org/wiki/Corrosionhttp://en.wikipedia.org/wiki/Corrosionhttp://en.wikipedia.org/wiki/Refrigeranthttp://en.wikipedia.org/wiki/Phase_changehttp://en.wikipedia.org/wiki/Latent_heathttp://en.wikipedia.org/wiki/Latent_heathttp://en.wikipedia.org/wiki/Latent_heathttp://en.wikipedia.org/wiki/Phase_changehttp://en.wikipedia.org/wiki/Refrigeranthttp://en.wikipedia.org/wiki/Corrosionhttp://en.wikipedia.org/wiki/Viscosityhttp://en.wikipedia.org/wiki/Thermal_capacity


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Unit 6 AUXILIARY MACHINERY

6.1 Auxiliary machinery

We usually have a purpose for reading a passage. If we know nothing about a subject, ourpurpose may be to gain a general knowledge of it. Later we may want to read about aspects ofit in greater detail. Comprehension will be made easier by giving ourselves a definite purposebased on our understanding of what the passage is going to be about from the title and theintroductory paragraph. This purpose will help focus our attention.

Besides running and maintaining the main propulsion machinery of the ship, the EngineerOfficer has a great deal of auxiliary machinery to look after. Auxiliary machinery coverseverything mechanical on board ship except the main engines and boilers. It includes almost allthe pipes and fittings and the equipment needed to carry out a number of functions. These

functions may be summarized as follows.

To supply the needs of the main engines and boilers. Air compressors are used to supplycompressed air for starting engines. Coolers are used for cooling either oil or water. Water forthe boilers is also heated before being admitted into the boiler by feed water heaters. Thisincreases the efficiency of the boiler.

To keep the ship dry and trimmed. This is done through the bilge and ballast pumping systems.The former removes water which has gathered in machinery, cargo and other spaces. The latterpumps water into and out of ballast tanks. In general cargo ships, these systems are usuallyinterconnected and served by the same pumps. In tankers and other bulk carriers, these systemsare entirely separate, because these ships may need to ballast at 12,000 tonne/hour and therefore

need larger pumps.

To supply domestic needs such as fresh water from distillation plant, sanitation from sewageplant and heating and ventilation from heaters and air-conditioners.

To apply the main power of the engines for propulsion and manoeuvring. The engine power istransmitted to the propeller by a line of steel shafting. This is made up of the thrust shaft,intermediate shafts and the propeller shaft. Steering gear is also necessary to operate the rudderfor manoeuvring.

To supply the ship with electrical power and lighting. This is done by steam or diesel-poweredgenerators.

To moor the ship and handle cargo. Deck machinery is extensive and varied. It can be dividedinto anchor-handling machinery - windlass and capstans, mooring machinery winches andcapstans, and cargo-handling machinerywinches and cranes. It also includes cargo oil pumps.

To provide for safety. Firefighting and fire detection equipment, lifeboat engines and launchinggear are also included;

Responsibility for auxiliary machinery is often delegated to individual engineer officers, each onetaking responsibility for the efficient working of certain items. A lot of equipment isduplicated, so that for example, one generator can be overhauled without cutting off the supplyof electricity to the ship. Engineer officers on tankers are also involved in operating the cargopumping machinery, although the pump rooms themselves are often manned by officers from the

Deck Department.


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6.2 Change of state verbs

Change from one state to another can be expressed verbally by:

1. Specific change of state verbs

e.g. to melt, to freeze, to condense, to rot, to rust

2. Verbs formed by adding -ify, -ize (-ise) to nouns and adjectives

e.g. solid => to solidify vapour => to vaporize

liquid => to liquefy crystal => to crystallize

(Note: changes of spelling are often necessary.)

3. General change of state verbsto become + adjective/noun

e.g. When air is compressed, it becomes hot.

When copper and tin are mixed, they become bronze.

to get + past participle/adjective

e.g. With poor lubrication, pistons get worn.

to turn + colour

e.g. Blue litmus paper turns red, if immersed in acid.

to change into + noun

e.g. Water changes into ice when the temperature drops below 0C.

to convert/be converted into + noun

e.g. At an oil refinery crude oil is converted into different oil products.

Exercise 1. Complete the following sentences by using one of the verbs above in the appropriate form:

(a) An interna l combust ion engine .................. chemical energy into

mechanical energy.

(b) With poor lubrication engine parts ............. worn.

(c) When gas is cooled below a certain temperature, it ..................

(d) The reciprocating motion of a piston .................. a rotary motion by

a connecting rod and crank.


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6.3 Comparisons

Comparative statements point out the difference or the equality between things. Statements

pointing out the difference can be made with:

1. Adjectives and adverbs in the comparative form + than

e.g. Cruisers are larger than frigates.

Water-tube boilers are more efficient than Scotch boilers. Light travels more quickly than sound.

2. More or less/fewer with noun + than

e.g. Less time is needed to load a container ship than a 'tween deck vessel. There are fewer

passenger liners today than there were thirty years ago. More money is now spent on fuel than

before. (Note: less is used with uncountable nouns, fewer with countables.)

Exercise 1. Rewrite the following sentences so that the part afterthan is put first, but the meaning stays

the same.

(a) A nautical mile is longer than a statute mile.(b) Manila rope is more expensive than sisal rope.(c) A diesel engine is more economical than a petrol engine.

(d) 100C is hotter than 100F.(e) The Chief Officer is senior to the Second Officer.(f) There are more members of the Catering Department in a passenger

liner than in a cargo vessel.

(g) Mercury freezes at a lower temperature than water.

(h) High carbon steel contains more carbon than mild steel.

(i) A ULCC is larger than a VLCC.

(j) A nuclear submarine is faster than a conventional submarine.

Statements making equal comparison can be made by

3. Using as ... as. The negative is not so/as ... as

e.g. The Deck Department is as important as the Engine Department. The Atlantic Ocean is

not as big as the Pacific Ocean. A Scotch boiler does not work so efficiently as a water-tube

boiler. With nouns this structure needs care. Study these examples:

(singular countable noun) e.g. Steel is not as good a conductor as copper.

( plural countable noun) A cargo ship does not have as many lifeboats as a passenger liner.

(uncountable noun ) A plane does not carry as much cargo as a ship.

Exercise 2. Rewrite these sentences using not so/as ... as, but without changing the meaning.

(a) A nautical mile is longer than a statute mile.

(b) Manila rope is more expensive than sisal rope.

(c) A diesel engine is more economical than a petrol engine.


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(d) 100C is hotter than 100F.(e) High carbon steel is harder than low carbon steel.(f) Fewer tankers will be built this year than last year.(g) Mercury has a lower freezing point than water.(h) A 'tween deck vessel has more decks than a single deck vessel, (i) Nowadays British ships

carry more tonnage than before, (j) A nuclear submarine has a higher underwater speed

than a conventional submarine.

Progress test

(Crossword puzzle). Fill in the definitions:


Complete the following sentences by using an appropriate verbs above in the appropriate for:

1. Water steam when it reaches boiling point.

2.Natural fibre ropes if allowed to remain\get .

3. When red litmus paper is placed in an alkali, it blue.4. Liquids ... less dense, when they are heated.

5. The sky often ... red at sunset.


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Unit 7 AUXILIARY ENGINES

7.1 Pumps

Aboard vessels several pumping-systems are used, and they are all essential for a smooth running

of all activities and proceedings on board the vessel.General service pumps serve all kinds of purposes. They may, for example, be used for domestic

use.

Ballast pumps are used to trim the vessel. A proper trim will enhance safety and reduce fuel

consumption. As a rule cargo vessels should not be trimmed down by the head, but must be slightly

down by the stem. Listing will occur when there is a difference between draft at port side and draft

at starboard side and must be remedied by ballasting the vessel.

Fresh water pumpsprovide water for cooling-systems.

Fire pumps are used to extinguish fires.

Fuel pumps (high-pressure fuel pumps and booster pumps) supply the fuel for the engine.

Lubricating oil pumps supply the lubricant forthe lubrication of engine parts.

Bilge pumps are used to drain superfluous liquids such as fresh and salt water, sweating water,oils, etc. from the holds. These pumps have been fitted with non-return valves that prevent the

liquid from flowing back through the lines. Before the mixture of oils and waters is dischargedinto

the mudbox, it is passed through a strainer that filters the substance.

The entire pumping-arrangement on board a vessel must be interconnected, so that in case of a

pump-failure in one system pumping can still be continued by other systems.

The most common types of pumps are the displacement pumps and the centrifugal pumps.

Examples of displacement pumps are the reciprocating pump and the gearwheel pump.

Reciprocating pump

In a reciprocating pump a piston (orplunger) moves up and down and forces the liquid in

and out of the pump chamberby creating a vacuum and a pressure force.

In a single acting reciprocating pump the liquid is drawn in when the piston goes up, and is

forced out when the piston goes down.

In a double-acting reciprocating pump the upward and downward motions of the piston

cause simultaneous suction- and dischargeactions.

When the piston goes down the lower chamber is emptied through the discharge valve (D2)

by pressure. The other discharge valve (D1) is closed by suction. The suction valve (31) is

opened by suction, allowing liquid to enter the upper pump chamber. The other suction

valve (S2) is closed by pressure. When the piston goes up, the reverse process will take

place.

Double-acting displacement pump


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The gearwheel pump

In a gearwheel pump the liquid (fuel oils and lubricating oil)

enters

through the suction side.

The liquid is then capturedbetween the teeth of the

gearwheels (cogs) and is carried around towards the dischargeside.

The centrifugal pump

The centrifugal pump only works when it has been immersedin the

liquid. In its stationary casing a rotating impeller causes a centrifugal

force that will discharge the liquid at high velocity through the discharge

line.

7.2 The anchor winch

Anchor winch (windlass)

The anchor winch is used to drop, heave in andpay out the

anchor.

It consists ofshafts and winding-mechanisms with brakes and

clutches. An electric- or electric-hydraulic motor drives the

driving shaft, which drives the intermediate shaft, which drives

the main shaft.

The main shaft is dividedinto two sections that carry the

starboard and port gearwheels and cable lifters. Cable lifters are

fitted with band brakes that control the dropping speed of the anchors.

The coupling between the gearwheel and the cable lifter is usually a dog clutch.

By shifting the cable lifter the anchor winch will be engagedor stopped.

The anchor chain is hove in through the hawse pipe and stored in the chain locker.

The intermediate shaft is fitted with warping drums at its extremities. Warping drums are used

to pick up any slackand keep the ship's lines tight. They are also used to shift the vessel's

berth. In this way the vessel will not have to use her engines when shifting berth along the

embankment.

7.3 The steering engine

A telemotor is a motor that is operated by means ofremote

control.

A typical example of the telemotor is the steering engine,

which operates the rudder. It is bridge-controlled, which

means that it is operated from the bridge by the mate or the

helmsman.

The most common type of steering engine consists of a

starboard- and port cylinder, in which rams are actuatedby

electronic signals that are transmittedwhen the steeringwheel on the bridge is turned. Steering engine

Centrifugal pump


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The two rams are connected to each other by a swivel blockin a crosshead. The crosshead is

fixed to the tiller. This tiller has an opening, called the rudder trunk. The rudder stockis part

of the rudder and goes through rudder trunk.

When the steering-wheel is turned, the pressure in the hydraulic system is built up, forcing the

ram in one of the cylinders to be pushed out and the other ram to be pushed in. This actuates

the crosshead with the swivel block and the tiller, causing the rudder to turn and the ship to

make an alteration of course.

7.4 Exhaust gas boiler

The effective power obtained from heavy fuel oil (HFO) is about

50% (provided that both engine and engineers perform their tasks

well). This means a heavy loss of energy, which for the major part is

wasted inthe exhaust gases through theflue andfunnel.

These gases are very hot, and by "capturing" this heat before it

escapes into the air, they are passed through an exhaust gas boiler.

The position of the exhaust gas boiler, or waste heat boiler, may be

in the engine room or in the funnel.

The idea is quite simple: instead of letting the exhaust gases escape

from the engine through the flue and funnel, the gases are first

passed through a boiler.

The type of boiler that is used for this purpose is often a so calledfire

tube boiler. It has a steam chamber in its hemispherical top.

The boiler shell consists of steel plates that are welded together. To

prevent any thermal loss and to protect the boiler shell from being

damaged by the heat, fire bricks are used.

Exhaust gases enter the boiler through the exhaust gas inlet. The exhaust gases heat up banks

offire tubes, which heat up the water in the boiler. The exhaust gases then leave the boilerthrough the exhaust gas outlet.

The water in the boiler is turned to steam, which may be used for heating purposes. On large

vessels the steam may even be used to drive a turbo-generator that will produce electricity that

can be used to drive auxiliary engines or for the lighting system.

The exhaust gas boiler is often fitted with an oil-firing installation. In such a case the boiler is

called a compound boiler, which means that it can be run both on exhaust gases and by oil

firing when the ship is in port and the idle engine does not produce any exhaust gases.

7.5 Generators

In order to provide electric power for the lighting system, auxiliaries, cranes, derricks, hatchesand for domestic use, the ship is equipped with one or more generators.

Aboard vessels a generator produces electricity of 380 volts or 440 volts.

The voltage can be stepped down (reduced) to 220 volts or even 110 volts by a transformer.

A generator produces either alternating current (A/C) or direct current (D/C).

A converteris used to convert (change) A/C into D/C.

Alternating current changes polarity about 50 times per second ("50 Hertz").

In the U.S.A. generators produce electricity of 60 Hz.

The main parts of a generator are the rotor, the stator and the commutator.

The rotor is a rotating electro-magnet. It produces a magnetic field.

The rotor rotates within the stator.

Around this stator, or armature, coils of wire are wound. These coils induce ("make") electriccurrent. The process is called induction. The induced current is collected by the commutator.


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Carbon brushes pass the current to the circuit.

Nowadays the modern generators do not have carbon brushes because they require regular

maintenance. Instead, the rotor is excitedby the direct current that is delivered by the stator.

7.6 Electric motors

Aboard vessels the electric motors and hydraulic systems perform most of the hard labour.

They are indispensable in daily operations. The maintenance and overhauling of electric

motors and appliances is therefore of the utmost importance.

Electric motors and generators are similar in construction.

The main components of an electric motor are the rotor and the stator (or armature).

In an electric motor the rotary motion of the rotor within the stationary stator is employedto

actuate pumps, winches, derricks, etc.

Most electric motors are run on alternating current (A/C).

The old-fashioned compound motorcombines the advantages of the even more old fashioned

shunt motor and the series motor. The compound motor has a high starting torque and a

constant running speed.

Nowadays we know two main types of electric motors: the a-synchronous induction motor,

which is widely used aboard ships, and the synchronous induction motor, which is hardly

used aboard ships.

The advantage of a-synchronous induction motor is the lack of vulnerable carbon brushes that

require frequent maintenance.

Its disadvantages are the large amount of initial current that it requires, and the low starting

torque it produces.

In the synchronous induction motor three-phase alternating current, either 220, 380 or 440

volts, passes through coils ofcopper wire in the stator, creating an alternating magnetic field.

Carbon brushes convey the current to the rotor, which will start to rotate.The advantages of the synchronous motor are the small amount of initial current it requires,

and its high starting torque. However, the synchronous motor is expensive, and the carbon

brushes require frequent maintenance.

7.7 Tasks: idioms, standard trouble-shooting orders

The italicized words in the text are given below in alphabetical order.


A/C - D/C carbon brushes crane

actuate casing crosshead

alteration of course chain locker delivery line

alternating current cogs derrick


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anchor winch coils direct current

appliance collect discharge

armature combine displacement pump

arrangement commutator dog clutch

band brake compound motor domestic

banks of fire tubes compound boiler down by the stern

bilge pump consist of down by the head

booster pump control drain

brake converter dropping speed

cable lifter convey effective power

capture copper embankment

employ hatch main components

engage hawse pipe maintenance

engineer heave in mate

escape helmsman mention

excitation hemisphere mixture

excite idle mudbox

exhaust gas boiler immerse non-return valve


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extinguish impeller obtain

extremity indispensable occur

failure interconnected oil-firing

fire bricks intermediate opposite

fire tube boiler labour overhauling

fitted with latter pay out

flooding lighting perform

flue lightning plunger

former list power failure

funnel lube oil provide

gearwheel pump lubricant pump chamber

ram single acting thermal loss

reciprocating slack tight

recover sphere tiller

reduce spherical towards

remote control starting torque transmit

rotary motion stationary trim

rotating statute mile velocity

rudder steam chamber warping drum


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rudder trunk steering engine waste

rudder stock strainer waste heat boiler

shaft suction weld

shift supply windlass

shifting berth sweating water wire

simultaneous swivel block

Standard Trouble-Shooting Orders

"Check.....": used very generally.

"Overhaul....." extensive repair.

"Overhaul or replace if nee......": used with mechanical appliances and parts that

havebeen composed of various components (e.g.

valve-mechanisms, pumps, etc.).

"Replace .....": If item is beyond repair: replace.

"Install.....": take out the old part and replace it by a new one.

"Remove.....": when parts are missing take away something that

shouldn't be there (e.g. "remove scale", or "remove

obstruction".)

"Clean .....": e.g. the outsides of engine parts.

"Adjust.....": set correctly in relation to other components (e.g. valve

clearance).

"Tighten .....": when components are not properly

connected(connections, lines, wires, etc.).

"Use proper (right) grade ....." in case of an improper (too low) viscosity or cetane-

grade.

"Heat up .....": when it is necessary to lower viscosity grade of oily

liquids.

"Raise temp......": heat up the engine room when starting at low ambient

temperature.

"Fill.....": in case of an empty reservoir (tank).

"Reduce level (drain).....": in case of a tank that has been filled without taking

into account the ullage-space.

"Use .....": any aid that will solve the problem (e.g."Use transfer

pump" when higher pumping-capacity is called for)."Charge.....": when a battery is undercharged.


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"Open ....." something that should not be shut.

"Close ....." Something that should not be open

Self-assessment test

Ask questions whose answers are the underlined words:

The maintenance to be expected with a ships propulsion machinery depends on the type of

machinery in question. For a steam turbine propulsion plant, the major maintenance items

are likely to be those associated with the boilers. Boiler tubes are subject to fouling on both

the water side and the hot gas side and may require periodic cleaning. Also, the refractory

material (firebrick) used in a boiler furnace may require occasional renewal. A boiler,

being a fired pressure vessel, is under legal stricture to have periodic safety inspections,

which require removal from service and opening.

Progress test

Find the right answer:

1. Heavy jobs on the steering gear should be done by:

A) Anyone who claims to be an expert on hydraulic components.

B) The chief engineer

C) A service engineer from the steering gear manufacturer

D) I don't know.

2. What is the purpose of the acknowledge function:

A) Tell the system that the alarm is registered.

B) Tell the system that the problem is solved.

C) Tell the system to ignore the alarm and continue to operate as normal.

D) I don't know.
http://www.britannica.com/EBchecked/topic/564539/steam-turbinehttp://www.britannica.com/EBchecked/topic/71774/boilerhttp://www.britannica.com/EBchecked/topic/475487/pressure-vesselhttp://www.britannica.com/EBchecked/topic/475487/pressure-vesselhttp://www.britannica.com/EBchecked/topic/71774/boilerhttp://www.britannica.com/EBchecked/topic/564539/steam-turbine

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