- S e c o n d A ss i st an t E ng i n e e r (2A E ) DIESEL ENGINE
1.Whathappenswhentoomuchcylinderoilisinjectedintheworking cylinder?
Ans. . Color of exhaust gas is bluish. . Formation of carbon
deposits on piston ring and ring grooves . Increase in cylinder oil
co nsumption2.Is the unit and normal value fuel ratio of an average
diesel engine? Ans. G/psh 20 - 130g/psh3.What is the formula for 1
HP of a two-cycle engine? Ans. IHP =PL AN c 33000 ft-LB/min4.Name
the indicator diagram. Ans. -Compression diagram-Out of phase
diagram/draw card-5.Power diagramLight spring diagramWhat are the 3
parts in indicator diagram? Ans. Maximum compression pressure,
maximum combustion pressure, means effective pressure.Japanese
Licensure Examination1
6.What are the causes of damage of diesel engine exhaust Valve?
Ans. -Exhaust valve leakage-7.Fuel contaminants ( Sulphur, Sodium,
Vanadium)Erosion and CorrosionWhat are the causes of lO. high
temperature in a diesel engine? Ans. -Clogged up cooling
tubes-8.Insufficient flow of cooling mediumIncorrect opening of
tempera ture control valveWhat trouble could result if the main
engine is using a low grade of fuel? Ans. Inefficient combustion
takes place -causing cylinder liner wear,
exhaustvalvewear,troublewithfuelinjectorsandpronetocarbon build-up
In the exhaust system.9.What are the causes of liner high
temperature? Ans. Engine is overloaded; insufficient
lubrication10.Whathappenwhentoomuchcylinderoilisinjectedintheworking
cylinder? Ans. Color of exhaust gas will be bluish. Excessive
carbon depo sit11.How many lubricating holes are there in cylinder?
Ans. Approximately 8.Japanese Licensure Examination2 12.What are
the defects in exhaust valves? Ans. -Excessive carbon residue at
spindle-13.Exhaust valve seat pitting/wearErosion and corrosionHow
do you control cylinder liner wear? Ans. -Correct liner and piston
ring clearances-Well maintained and timed fuel injectors-Proper
fuel and LO treatment process-Usage of LO. with properties ( Total
Base Number)-Correct scavenging air temperatures-14.Sufficient
lubricationCorrect Cooling water an d lubricating oil
temperaturesHow much is the specific fuel consumption of an average
diesel engine? Ans. 120-130 G/PS-Hr15.Purpose of lubricator in a
large diesel engine. Ans. To pump oil into the cylinder passing a
number of lubricating orifice during the upward stroke.16.Explain
how the cylinder lubrication on main engine is done? Ans.
lubricators are usually supplied with oil from a day tank, The
through a gravity, which equipped with a built in float, strainers
and stop valves. The oil Is pumped into t he cylinder by lubricator
pumpvianon-returnvalve,passinganumberoflubricatingorifice during
the upward stroke. The oil feed rate or dosageJapanese Licensure
Examination3 shouldbeinrecommendationaccordance andshouldwith
betheengineincreasedduringbuilder's starting,maneuvering and large
changes in engine load.17.Explain the function of cooling water
expansion tank. Ans.
TomaintainsufficientcoolingwaterintheF.W.C.systembygravit y. To
reduce air or steam pocket s Allow changes of the cooling water
volume due to hea ting and cooling Maintains a constant head in the
system18.Explain the causes of the exhaust valve leakage. Ans.
Corrosion/Wear of exhaust valve seat19.What is the purpose of l.O.
circulation before and after starting of engine? Ans . The purpose
of l.O. circ ulation before starting of engine is to prevent
seizure of metal parts especially the cylinder and the piston.
While after stafting of engine and continuos running, is to prevent
metal to metal contact and reduce friction and wear at a moving
parts. It als o serves a cooling medium between metal
parts.20.Names of valve connected in cylinder head of the engine.
Ans. 1. Relief valve 2. Fuel injector valve 3. Indicator valve 4.
Starting air valve 5. Exhaust valveJapanese Licensure Examination4
21.Name the safety devices of diesel engine? Ans. 1.Relief valves
fitted to the chamber to warn of excessive increase in combustion
pressure.2.Relief valves fitted to the crankcase to act, as safety
valves should oil vapor ignite due, for instance, to a hot
bearing.3.Reliefvalvesfittedtoscavengespace stoprotectthechamber
against high pressure, 4.Relief valves for fuel pumps and fuel
system to prevent line from bursting.5.Relief valves for starting
air system to prevent excessive pressure and flame traps or
bursting disc at each starting air valve.6.Interlocks fitted to
turning gears to ensure that the engine cannot be started whilst
the turning gear is engaged.7.Automatic shut down of the engine due
to low pressure in the lubricating or cooling
system.8.Automaticshutdownoftheengineduetohigh/lowtemperature in
various systems.
9.Shutdowntheenginefromthebridgeshouldthecommunication with the
engine room fail when the vessel is in hazardous posItion.
10.Over-speed trip which cuts the fuel supply to the engine
shouldthemaingovernorfailandtheengineRPMincreases. 11.Oil mist
detector fitted in the crankcase to give warning of hot running
parts.12.A temperature probe system fitted to bearing to give alarm
of excessive
temperature.13.Atemperatureprobesystemfittedinthescavengeairspace
to indicate scavenge fires.22.What is injection lag? Ans.Japanese
Licensure Examination5 After compression fuel is injected and comes
in contact with hot compressed air, total combustion of fuel does
not occur instantly (time delay of ignition) due to the quality of
IFO.23.Explain how to measure crank web deflection? Ans. Crankshaft
alignment can be checked by taking deflections. A
Straingagearrangehorizontallybetweenthecrankwebsopposite the crank
pin and ideally at the circumference of the main journal will give
horizontal deflection, wh en the crank is rotated through one
revolution, that is directly proportional to the vertical
deflection. becheckedagainstVertical and horizontal misalignment
can thepermissiblevaluessuppliedbytheengine builder.24.In a 4cycle
engine the intake val ve begins to open at ? Ans. Intake
stroke25.What causes cylinder liner - wear down? Ans. a.
insufficient lubrication b. excessive load c. poor combustion d.
incorrect L.O. properties used e. poor quality of fuel oil
used26.What causes diesel engine to automatically stop? Ans. a.
Over speed b. Low L.O. pressure of System. Crosshead and cylinder
L.O. c. Low pressure and high temperature of cooling water27.What
causes crankcase explosion? Ans. a. blowpast of hot gases inside
the underpiston?Japanese Licensure Examination6 b. Formation of
flamm able vapor inside the crankcase c. Presence of hot spot
inside the crankcase (Main Bearing) d. Excessive crankcase
pressure28.Whatdoyoucalltheclearingofairinsidecylinderaftercombustion?
Ans. Scavenging method ( Uniflow , Loop and Cross scavengin
g)29.What is the circulation of l.O. pump to diesel engine? Ans.
Sump tank.. ~ Suction strainer ~L.O. pump ~ L.O. cooler ~ Aut o
backwash filter L.O. ~ M/E30.What causes diesel engine trouble when
using heavy oil? Ans. a. poor combustion b. excessive formation of
carbon deposits c. excessive corrosion and wear of engine parts d.
high thermal load31.What causes turbocharger surging? Ans. a.
fouling of turbocharger b. rough sea condition c. contamination of
exhaust and scavenging ducting ports and filters d. variation in
gas supply to turbo charger due to unbalanced output. e. Mechanical
damage in turbo charger32.What pressure is highest L.O. Gravity
Head or S.W. of the stern tube circulation Ans.Japanese Licensure
Examination7 Pressure of L. O. gravity tank 33.What is fuel
catalytic cracking Ans. Method of separating fuel into different
grades by the use of a catalyst.34.Contaminants of fuel oil Ans. 1.
Sodium-iscontaminantwhichmaybepresentduetoseawater in the fuel. 2.
Vanadium removedand byneutralizedSulfurthe by-arepurifier.
alkalidissolvedTheeffectadditivesinin
ofthefuelthedieselandsulfurenginecannot becylinderlubricants. 3.
Silicon purifierand oraluminum
clarifierI-catalyticbutslowfinesarethroughoutremove
isintheessentialforoptimum results.35.Crankcase oil mist detector
Ans. it uses photoelectric cells to measure small increases in 011
mist density which is harmful and may lead to crankcase
explosion.36.Inspection for intermediate shaft bearing. Ans. Shaft
bearings are of two types, the aftermost tunnel bearing and all
others. The aftermost tunnel bearing has a top and a bottom bearing
shell because It must counter act the propeller mass and take a
vertical upward thrust at the forward end of the tailshaft. The
intermediate shaft bearing only support the shaft weight and thus
have only lower half bearing shell. lubrication is from a bath in
the low er half of the casing and should be inspected. Also t he
cooling process by water circulating through a tube cooler in the
bottom of the casing.37.What are the causes of main engine bla ck
smoke? Ans. 1.Poor atomization of fuelJapanese Licensure
Examination8 2. 3.Insufficient air (Restricted air Intake
system)4.Damaged piston rings and exhaust valve5.low fuel oil
pressure and temperature6.38.Damaged fuel injectorsFouled Exhaust
gas EconomizerCauses of emergency trip of diesel en gine Ans. 1.low
lube oil
pressure2.Shutdownoftheenginefromthebridgeshouldthecommunication
fail while the vessel is in hazardous position. 3. 4.Control air
failure5.39.Over speeding, governor failureJacket cooling water
high temperatureWhat are the causes if one cylinder In a diesel
engine has a high temperature? Ans. 1.Damaged exhaust
valves.2.Poorjacketcoolinginasinglecylinderduetoscaleformation. 3.
4.Damage exhaust valve5.Clogged scavenging port6.40.Damaged fuel
injector nozzles.Excessive cylinder and piston ring wearExplain how
the lubricating oil circulates in a diesel engine. Ans. Lubricating
crankcase,foranknownengine astheisstoredpump,orin
inathebottomdraintankofthelocatedbeneath the engine. The oil is
drawn from the tank throu gh a strainer, one of a pair of pumps,
into one of a pair of fine filters. It is then passed to a cooler
before entering the engine and being distributed to the various
branchpipes. The branch pipesfor a particular cylinder may feed the
main bearing, fo r instance.Japanese Licensure Examination9
Someofthisoilmypassalongadrilledpassageintheconnecting rod t o the
gudgeon pin or crosshead bearing. An alarm at the end of the
distribution pipes ensures that adequate pressure is maintained by
the pump. Pumps and fine filters are arranged in a duplicate with
one standby. The fine filters will be arranged so that one can
clean while the other is operating. After used in the engine the
oil drains back to a sump tank or a drain tank for reuse. A level
gauge gives a local read -out of the drain tank contents. A
centrifuge is arranged for cleaning the lubricating oil in the
system and clean oil can be provided from a storage tank. The oil
cooler is circulated by seawater, which is at a lower pressure than
the oil. As a result any leak in t he cooler will mean a loss of
oil and not contamination of the oil by seawater.41.What are the
causes of damage to propellers? Ans. ~ Cavitation - the forming and
bursting of vapour filled cavities or bubbles, can occur as result
of pressure variation at th e back of a propeller blade. ~
Corrosion ~ Small Cracks - due to loads and wears. ~ Grounding -
this causes bents and worn out propellers.42.What causes friction
in the cylinder? Ans. 1. 2.Faulty combustion.3.Used of incorrect
cylinder oil.4.43.Inadequate or incorrect lubrication.Overloading
of the engine.What causes damage to impellers? Ans. 1.Over
speeding2.Vibrations3.CorrosionJapanese Licensure Examination10
4.44.WearsIn a four-stroke diesel engine, in what stroke exhaust
valve will open? Ans. Exhaust Stroke45.How is propeller fitted in
shaft? Ans. The propeller is fitted unto a taper on the tailshaft
and a key
maybeinsertedbetweenthetwo;alternativelyakeylessarrangement maybe
used. A large nut is fastened and locked in place on the end of the
taishaft; a cone is then bolted over the end of the tailshaft to
provide a smooth flow of water from the propeller.46.What valves
are fitted in a four-stroke diesel engine? Ans. Exhaust valves and
intake valves.47.What are the automatic tripping devices of diesel
generator? Ans.
1.Automaticshutdownoftheengineduetohighorlowtemperature in various
systems. 2.Automatic shutdown of the engine due to low pressure in
the lubricating or cooling system.3.48.Over speed tripWhat is the
purpose of thrust bearing? Ans. Its purpose is to transmit thrust
of the propell er to the hull to prevent the main engine from being
forced out alignment.Japanese Licensure Examination11 49.What is
fuel oil viscosity, specific gravity? Ans. Viscosity is the
resistance to flow specified by Redwood Viscosity in Seconds being
replaced by Kinematic Viscosity in Centistoke s. The specific
gravity or relative density is the weight of a given volume of fuel
compared to the weight of the same volume of water expressed as a
ratio and measured at a fixed temperature.50.What are the causes of
low compression in the main engine? Ans. 1. 2.Damaged
valves3.Leaking cylinder head4.Cam not in proper
position5.Restricted air passages6.Back pressure of exhaust due to
fouled Economizer7.51.Worn out piston rings.High scavenging air
temperatureWhat do you measure in the banana and mountain diagram?
Ans. Therelationsofpressureandvolumearemeasuredinthisindicator
diagram. The compression, power and expansion curves are
shown.52.What is a brake horse power? Ans. The power developed by
an engine as measured by the force applied to a friction brake or
by an absorption dynamometer applied to the shaft or
flywheel.Japanese Licensure Examination12 53.What are the
requirements of a good fuel? Ans. The fuel oil must have a good
viscosity at specific gravity. The ignition quality should have of
higher value for better ignition. The flash point must be also
obtained for maximum safe storage.
Thepourpointandcloudpointmustbegood.Lowsulphurcontent to minimize
engine wear. No water content and free from dirt and solid
particles such as sand and small metal chips.54.What is the purpose
of a settling tank? Ans. The purpose of a settling tank is for fuel
oil to settle down before it is drawn by purifiers and delivers it
to the service tank.55.What is the purpose of the turning gear?
Ans. The purpose of the turning gear is to revolve the cr ankshaft
of the engine while in stop position. This is done for the purpose
of inspection and maintenance work.56.What is the purpose of
starting air? Ans. Starting air is used to initially turn the main
engine and other auxiliary engine during starting by the use of
pressurize air.57.What is the purpose of engine preheating? Ans.
The engine must be preheated to warm up the engine and reach the
temperature at which it will be easier to start. This is done to
avoid sudden rise of temperature during combustion which may result
to thermal cracking and stress to the metals.Japanese Licensure
Examination13 58.What is the purpose of air blow? Ans. Air blow is
done to clear and check the combustion chamber from any leaks of
jacket water and accumulation of moisture present before starting
the engine to prevent for hydraulic knock.59.What is the purpose of
stern tube? , Ans. Stern tubes are constructed to secure an hold
the tailshaft and prevent seawater from entering.60.Where can you
find thermometers in diesel engines? Ans. Thermometers can be found
o n exhaust ports, jacket cooling lines, fuel oil lines and
lubricating oil lines.61.What would happen if there is air in fuel
oil? Ans. a. Poor combustion fuel. b. Injection valve will not
function properly. c. Air pocket . d. Damage to engine parts. e.
Pulsation of fuel oil lines e. Stop or operate with reduced power
f.62.Failed to startWhat type of pump is lubricator pump? Ans.
Positive displacement63.What is the purpose of piston rings?
Ans.Japanese Licensure Examination14 The piston is so attached to
the piston to prevent combustion gasestoleakbetweent
hecylinderandpistonduringcombustion. To provide a gas tight
sealing.64.The advantage of a controllable pitch propeller? Ans. 1.
2.65.It allows the main engine a single direction rotation. Fast
action on reversing.Explain the fresh water cooling system s. Ans.
The high temperature of the working cycle would quickly heat up the
metal forming the cylinders, cylinder covers and pistons if steps
werenot taken to prevent this happening. It is necessaryto keep the
piston rings at temperatures sufficiently l ow for the lubricating
oil surrounding them to survive and mechanisms such as fuel valves,
exhaust valves and starting air valves must be kept at temperatures
at which they will work satisfactorily and remain
lubricated.Alsothemetalofpartsformingthecombustionspaces must be
kept at a temperature low enough to avoid losing mechanical
strength. The necessary control of temperature is carried out by
the surrounding the cylinders with a jacket and by providing
cylinder covers and pistons with passages t hrough which the
cooling fluids maybe passed. The coolant is fresh water in the case
of the cylinder covers. Pistons are cooled by fresh water in some
designs and by lubricating oil in others.
Theheatpickedupbythesecoolingfluidsistransferredtoseawater in heat
exchangers and thus rejected to the sea, the cooling fluids
becoming cooled and ready to circulate the jacket spaces again. Sea
water cannot be used readily in the cooling spaces of modern
engines as it Is both corrosive and liable to leave deposit s. OPEN
AND CLOSED FRESH WATER SY STEM A fresh water system may be open or
closed. In the open system water is drawn from a tank at
atmospheric pressure, it is pumped through a heat exchanger (often
termed the jacket water cooler) and then upwards th rough the
engine emerging from the top ofJapanese Licensure Examination15 the
engine. There are usually a number of outlets; one for each
cylinder or cylinder cover and one for each piston if the pistons
are water cooled. The cooling water spaces of turbochargers are
usually included in the circuit also and will each have a water
outlet. The water from these outlets is led to a hopper or tun dish
which serves as a visual flow indicat or. At this point the wat er
reachesatmosphericpressureagain.Eachtundishisusuallyencased and
viewed through a glass window in tne interests of safety and
cleanliness. From here the water descends by gravity to the drain
tank, the individual outlets usually being gathered together at a
convenient point en -route. In the closed system there is no
collectin g tank. The engine jackets, the heat exchanger and the
pump form a continuous circuit which is not open to the atmosphere.
However, provision has to bemadefor theexpansionofthe waterdueto
theincrease in temperature and due to small amounts of air w hich
may enter the system and become entrained. These eventualities are
met by a small header tank. The header tank is open to the
atmosphere and place at a higher level than any other point in
thesystemchangesinvolumecanbeaccommodatedbychanging the level of
the free surface of the water in the tank. The header tank is
generally connected into the system at the pump suction, as this
minimizes the chance of air being drawn into the system at the
pump. With closed systems it is customary for the pump to circulate
the water first to the engine jackets and then to the heat
exchanger. The minimum height of the header tank may be based on
maintaining pressure of fresh water in the heat exchanger above
that of the sea water to ensure that in the event of a small
internal leak developing sea water cannot enter the fresh water
system. Alt ernatively, it may be based on the for a minimum
pressure to be maintained within the jacKets to avoid cavitation
effects. The maximum height of the header tank is determined by the
pressure which joints and seals in the fresh water system can
withstand. Open systems are self-venting but closed systems usually
need vents if steam pockets or air locks are not to cause trouble.
Vent pipes of small bore tube are lead from any loc al high point
in the system to the top of the header tank so that the steam or
air does not collect in these local high places. The temperature of
the water entering the engine jackets is regulated by means of a
by-passacrosstheheatexchanger.Thepropo rtionofwaterpassing through
the cooler, or by -passing it are controlled by a three way valve
arranged either as a diverting valve if upstream of the heat
exchanger, or as a mixing valve if downstream. TheJapanese
Licensure Examination16 temperature is usually adjusted to maintain
a co nstant outlet water temperature from the engine regardless of
the load or speed or the temperat ure of the sea wat er. Almost alw
ays t his is done automatically by using temperature sensitive
controls for the valves. Fuel Injector valves require precise contr
ol of the temperature at the tip of the nozzles; too high a
temperature leading to the
formationofcarboncorrosion.Theyaretrumpets,
generallytooIowaprovidedtemperature withacausingcoolingwatersystem
which is either a branch of the jacket wate r system or an entirely
separate circuit. Ineither case there will be a separateheat
exchanger or a cooling tank and some means of adjusting, or at
leastsetting, the rate of flow to the injector whichisindependent
of that flow to the engine cylinder jackets.66.What are the typical
indicator diagrams? Ans. The power and draw cards should be closely
studied. Diagrams given are for compression ignition engines of the
2 and 4 stroke types. Pressures and temperatures are shown on the
sketches where appropriate. The draw card is an extended scale
picture of the of the combustion process. In early marine practice
the indicatorcardwasdrawnbythehand -hencethename.Inmodern practIce
an 'out of phase' (90 degrees) cam would be
providedadjacenttothegeneralindicatorcom.Incorrectcombustion
details show readily on the draw card. There is no real marked
difference between the diagrams for 2 stroke or 4 stroke. In
general the compression point on the draw card is more difficult to
detect on the 2 strok e as the line is fairly continuous. There is
no induction - exhaust loop for the 4 stroke as the spring used in
the indicator is too strong to discriminate on a pressure
difference of say 1/3 bar only. With the fuel shut off expansion
and compression shoul d appear as one line. Errors would be due to
a time lag in the drive or a faulty Indicator com
settingorrelativephasedifferencebetweencamshaftandcrankshaft.
Normally such diagrams would only be necessary on initial engine
trials unless loss of comp ression or cam shift on the engine was
suspected.Japanese Licensure Examination17 67.What is the trunk
type and crosshead type piston Ans. Trunk type - work done in the
piston is directly transmitted to the crankshaft Crosshead type -
the piston is connected to a vertical member, the lower end of
which is attached to a sliding member called a crosshead. It moves
up and down in guides and is connected on the lower end of the
connecting rod.68.What is higher IHP or BHP Ans. IHP is always
higher than BHP69.What is the sensitive part of the li ner Ans. The
upper most portion of the liner is the most sensitive part. It is
where high pressure and temperature occurs.70.Discuss how to
prepare the M/E in standby condition Ans. I.Before a large diesel
is started it must be warmed through by circulating hot water
through the jackets, etc. This will enable the various engine parts
to expand in relation to one another.2.The various supply tanks,
filters, valves and drains are all to be checked.3.The lubricating
oil pumps and circulating water pumps are started and all the
visible returns should be observed.4.All cont rol equipment and
alarms should be examined for correct operation.5.The indicator
cocks are opened, the turning gear engaged
andtheengineturnedJapanese Licensure
Examinationthroughseveralcomplete18
revolutions.Inthiswayany.waterwhichmayhavecollected in the
cylinders will be forced out. 6.The fuel oil system is checked and
circulated with hot oil.7.Auxiliary scavenge blowers, if manually
operated, should be started.8.The turning gear is remov ed and if
possible the engine should be turned over on air before closing the
indicator cocks.9.The engine is now available for standby.
Thelengthoftimeinvolvedinthesepreparationswilldepend upon the size
of the engine.71.Explain now to clean LO Ans. L.O. requires
treatment before passing to the engine, This will involve storage
and heating to allow separation of water present,
coarseandfinefilteringtoremovesolidparticlesandalsocentrifuging.72.Explain
the principle of Sulzer Fuel oil inj ection pump Ans. Sulzer
engines are provided with a fuel pump of timed double valve type,
driven by the camshaft. Each pump consists of a plunger and guide
bush and a driving piston. The roller is kept in contact with the
cam by a powerful spring. A fuel p ump can be taken out of service
by a mechanical cut -out lever, which lifts the driving piston and
roller clear of the cam. This lever can also be used for priming
the injection system. The fuel pump delivery is controlled by
suction and spill valves. As the suction valve remains off its seat
no fuel is delivered.
Whenthefuelpumpplungerisraised,thesuctionvalveislow ered on t o it
s seat . As soon as the suction valve closes, fuel is delivered.
effectiveNormally strokeisthestartcontrolledofdelivery
byisadjustingconstant theandspillthevalve.Retarding the spill valve
increases the effective delivery stroke, while advancing reduces
the effective stroke. These adjustments mustbemade whentheengine
isstoppedandnever whenrunning. Ignition pressures are equalised
only by turning the camsJapanese Licensure Examination19 and not by
altering the length of the pushrod. The fuel charge for
individualcylinderscanbe temporarilyreduced, for instancewhen
running in a spare part such as a liner or piston, etc. by fitting
a spacer between the pushrod and the regulating rod. This raises
the suction valve by 2.4 mm. When adjusting the fuel pump control
valves no spacers should be fitted.73.What is the volume develop by
the piston from BDC to TDC Ans. Swept volume is volume swept by the
piston from BDC to TDC74.Enumerate some trouble of fuel injection
valve Ans. -stuck-up needle-75.leaking F.O. injection valveclogged
up atomizerCauses of M/E high exhaust valve temperature Ans.
-leaking hot combustion
gas-Incompletecombustionleadingtohighexhausttemperature I 76.
.Insufficient cooling of valve seatWhat is the purpose of scrapper
ring Ans. Scrapper ring distributes the cylinder oil injected in
the surface of the cylinder.77.What are the items to inspect after
cylinde r liner is pulled out Ans. -corrosion of the
flange-circumferential crack of the fillet shoulderJapanese
Licensure Examination20 -longitudinal crack of the inside of
liner-crack on corner of the oil hole and oil groove-crack and
corrosion of cooli ng surface-condition of liner surface-condition
of lubrication-78.wear down and corrosion of sliding
surfacecylinder liner wearWhat resistance the ship encounter when
the vessel is at sea Ans. -Hull resistance due to marine
growth-79.Wave resistanceWeather (rough wind and sea condition)What
will you do in case of scavenging fire Ans.
-Whenalarmhasbeengiven,thespeedoftheengineshould be reduced to slow
and fuel cut off to the particular cylinder. The cylinder oil
supply should be maintained or even increased.
-Thebridgemustbeinformedandpermissiontostoprequested. Cut out fuel
priming pump. Personnel must keep clearfromequipmentdoors
isandfittedrelieftothevalves. airWherereceiverthisfire -fighting
shouldbebrought into operation as soon as possible. If no equipment
is available the fire will generally subside in about five to
fifteen minutes. -Do not open scavenge space doors or crankcase
doors before the site of the fire has cooled down. When opening up
care must be taken to keep cleat of any flame.-After opening up all
scavenge spaces must be thoroughly cleaned and all debris
removed.-The piston rods and cylinder liner should be examined for
surfaceblemishes,straightnessetc.,andthediaphragmglands examined to
ensure that they are operational and not damaged.Japanese Licensure
Examination21 If possible the piston head in question should be
renewed-attheearliestpossiblemomentandthedamagedunitoverhauled. On
engines fitted with tie bolts it may be necessary to re --tighten
the bolts adjacent to the fire. The-flatexaminedsurfaces
forofthedistortionasscavenge alignmentspace
ofshouldthebecamshaftbearings and the cylinder liners etc may be
affected. When starting the engine again care must be taken
after-switching on the fuel to the cylinder in question that the
cylinder lubricating oil quantities are reduced to normal. Due to
the large volume of air being blown through the receiver the
formation of an explosive gas/air mixture Is extremely improbable.
Conscientious-maintenanceoftheengineandregularinspection and
cleaning of the scavenge air spaces will help to eliminate scavenge
fires.80. .Draw the flow of F.O. diagram from service tank to main
engine? Ans.81. What are the types of cleaning main engine Turbo
charger blower side? Ans. ~ Water washing82.What are the causes of
main engine Turbo Charger blower side dirty? Ans. ~ Poor combustion
due to low grade fuel ~ Damaged air filter83. .Sketch the jacket
coling system. Ans.Japanese Licensure Examination22
84.WhatwillcauseifyourunyourengineincriticalRPMcontinuously? Ans.
It affects the torsional load resulting to torsional vibration. The
first mode of torsional vibration in the shafting system will have
to noode and the highest torsional alternating stresses occur
immediately aft of propulsion of the engine, for vessels with
fairly long runs shafting, the first mode frequency usually occurs
at a low shaft rpm.85. What are the properties of fuel oil? Ans. ~
Sulfur -is present inmost crude oils to varying degrees and
ischemically bound in the fuel, the higher viscosity residual
fractions tend to have higher sulfur contents. ~ Carbon residue -
is the percentage of coked material remaining the sample of fuel
oil has been exposed to high temperatures. Carbon
reachfuelsaremoredifficulttoburnandtherefore,havepoorcombustion
characteristics which lead to the formation of soot and
carbondeposits.Sincecarbondepositscanbemajorsourceofabrasive wear,
the fuel carbon residue value may be an important parameter in the
operation of a diesel engine. ~ Asphalt enes - are those component
s of asphalt that are insoluble in petroleum ~ Naphtha but are
soluble in carbon disulfide. They can be hard and brittle, are made
up largely of high molecular weight, polynuclear
hydrocarbonderivativescontainingcarbon,hydrogen,nitrogen,oxygen,
and usually one or more of the three heavy metals - nickel, iron,
and vanadium as well as sulfur. ~Compatibilitybecome cuttermore
stocks-isveryintensely ofimportantrefi
ned,lightthedistillatefuelquality,resulting toasfuelproducea
isresidual blendedusableoils withhandlingcharacteristics. When
light fractions with predominance of aliphatic hydrocarbon are
mixed with a heavy fuel, the collidal dispersion of highmolecular
weightsubstancesisdisturbed. Due to thislossofequilibrium, the
heavier constituents tent to precipitate, This is usuallyJapanese
Licensure Examination23 seen as sludge formation, causing clogged
strainers and fouled filters and purifiers. ~ Vanadium - is a
metallic element that is che mically bound in oil in the form of a
soluble organometallic compound. The vanadium levels in residual
fuels vary widely, depending the origin of crude oil, when present
in critical amounts which vary with temperature involved, it forms
adherent slag on high temperature surface, which include the super
heater tubes in steam plant boilers and the exhaust valve and seats
in valved diesel
engines,aswellaspistoncrowns,causinglocalizedhotspotandeventual
burning of high temperature surfaces. ~ Nickel - is another
metallic element that is found in heavy crude oils, but in smaller
amounts than vanadium. When compared to vanadium the combustion
problems associated with nickel are minor.
~Sodium-isanalkaline,metallicelementthatisfoundonlyincombined form,
one of which is common salt, sodium salt (NaCI). Most sodium
compounds are watersoluble. Sodium found in fuel can comeseveral
sources but most of it is a direct result of storing and handling
procedures from the time fuel leaves the refinery u ntil it is
delivered to bunkers. Salt water contamination in barges used to
transport fuel is not uncommon, to some extent even salt air
condensation in fuel tanks contributes to a fuel overall sodium
content. Regardless of the manner ofcontamination, sod iuminfuelis
usually watersolubleand cantherefore, be removed with the water by
a centrifugal separator. ~ Ash cont ent - The ash content of a fuel
oil is a measure of the
metalliccontentandthenoncombustibleinorganicsolidcontamination in
the fuel. The ash content specially of heavy fuels, provides a
method of assessing the quality of fuel oil and takes into account
dispersedcharacteristics anddissolvedsuchassolidcompoundsforeign
metalsofmaterials suchasandthevanadium,sodium, iron and nickel.
~Oxidationstability,productsespecially-Residualwhenfuelsmaintainedmay
inahaveaheatedpoorstorageconditionforext ended periods of time. As
fuel ages it becomes oxidize by air and begins to polymerize,
forming sludge, gums, and res ins that can foul filters and heaters
and can sometimes cause fouling of the injectors, combustion
chambers, and exhaust system. Oxidation products can remain soluble
in the fuel or become insoluble and precipitate out, forming an
organic sediment. ~ Sediment - in fuels consists of insoluble
matter, which may include
sand,rust,andcatalyticfinessuchastarlikepolymerizedhydrocarbons and
precipitated asphaltenes, both of which break downJapanese
Licensure Examination24 under the heat of combustion and form
lacquer and tarry deposits that impair the movement of parts and
sometimes interfere with fuel nozzle
spraypatterns.Sedimentscontainingabrasivematerialsorlargeamount
organic materials can damage high pressure fuel pumps and fuel
nozzles. Sediments are removed by centrifuges and filters.86. What
will you check if one cylinder of your engine is not like the
others? Ans. ~ Exhaust temperature ~ Jacket cooling water outlet
temperature ~ Fuel pump rack scale ~ Fuel injection timing ~ Fuel
injector atomization and opening pressure ~ Check Pmax and Pcom87.
What do you do when in your duty, ME alarm oil mist detect high
density? Ans. ~ Reduce speed to slow down level ~ Ask the bridge
for permission t o st op ~ When engine stop order is received, stop
the engine and close thefuel oil supply ~ Switch off the auxiliary
blowers ~ Open the skylights and/or store hatch ~ Leave the engine
room ~ Lock the casing doors and keep away from themMEASURES TO BE
TAKEN WHEN OIL MIST HAS OCCURRED: ~ Don'tstand near crankcase doors
or relief valves nor in thecorridors in the engine room casings. ~
Don't open crankcase until 30 min. after stopping the engine. ~
When opening-up keep clear of possible spurtsof flame andavoid
naked lights.Japanese Licensure Examination25 88. Classification of
bunkers? Ans. ~ Specific gravity at 15 deg centigrade ~ Flashpoint
~ Viscosity ~ Water content ~ Sulfur content ~ Temperature89. What
is the purpose of increasing the pressure on the F.O system of the
engine? Ans. To open the fuel oil injector to the desired opening
pressure for good atomization.90. What are the advantages of white
metal? Ans. ~ Easy to manufacture ~ Relatively cheap ~Uniform
microstructure~ Good bearing surface ~ Good anti frictional
properties91. What is the use of white metal? Ans. Production of: ~
Main bearing ~ Bottom end bearings ~ Stern tubes ~ Propeller shaft
bearings ~ Crosshead and top end bearings92. What is the cause of
cylindrical liner overheating?Japanese Licensure Examination26 Ans.
~ Too high thermal load or overloading ~ Lack of cylinder
lubrication ~ Faulty injector
nozzles93.Whatareyougoingtoinspectorcheckwhenyouopenthecrankcase?
Ans. ~ Check the tension of all bolts and nuts ~ Check the presence
of cracks on engine frame ~ Check the presence of foreign matters
and particles of metal in the crankcase ~ Visually check the oil
circulation for bearings and gears ~ Check the camshaft driving
gear94. Draw L.O. system in diesel engine Ans.95. What is the
specific gravity of F.O and C.O? Ans. ~F.O - .9 to .9 grams !cubic
centimeter~ 0.0 - .85 grams! cubic centimeter96. What is pou point?
Ans. This is a determination of the lowest temperature value at
which oil will pour or flow under the prescribed test condition.97.
What is flashpoint? Ans.Japanese Licensure Examination27 Is the
minimum temperature at which enou gh fuel vapors will exist to
support momentary combustion when an ignition source is present
near the fuel surface.98. What materials are used for engine
propeller? Ans. ~ Copper base alloys ~ Manganese bronze ~Nickel
aluminum bron ze~ Manganese nickel aluminum bronze99. How fuel oil
consumed by medium engine? Ans. 30 metric tons100. What is the
remedy if due exchanging, valve broke out during engine running
operation? Ans. ~Cut off the fuel pump by li fting and securing the
roller guide~ Put the exhaust valve out of action sothat the valve
remainsclosed (lift the guide or stop the oil supply and remove the
hydraulic pipe) Spring air to be supplied.101. At 50 Centigrade
(Fuel oil) what is its cst? Ans. 380 Cst102. At 50 Centigrade
(Diesel oil) what is its cst? Ans. 180 Cst 103. What do you call a
piston travel from TDC to BDC? Ans. Piston displacementJapanese
Licensure Examination28 104. What happened if the exhaust valve is
leaking ? Ans. ~ Low combustion pressure ~ High exhaust gas
temperature105. Why and what cause of leak fuel oil in high
pressure pipe of main engine? Ans. ~ Vibration of engine ~ Material
fatigue/cracks ~Lack of tightening torque~ Unbalanced tightening
~Unequal surface between metal contact106. What device installed in
the F.O system when excess oil return to drain tank? Ans. Fuel oil
backwash filter / Main engine 2nd and 3rd Filter 107. What
parameters to be reported when we send lubricating oil for shore
analysis? Ans. ~ Lubricating oil running hours ~ Viscosity
~Sampling point or origin of oil~Type or grade of oil108. Heavy
fuel oil sulfur content and counter measures? Ans. 4% sulfur
Counter measures ~ Use of cylinder oil with TBN to neutralize the
formation of acidsJapanese Licensure Examination29 ~ Avoid low
combustion temperat ure and eventually leads t o excessive liner
wear ~ Maintaining the surface temperature of cylinder liners an d
valves stems sufficiently high to prevent sulfuric acid
condensation. ~ Lubricating oil analysis program is required to
assured a correct acid
/alkalinebalancethatprovidestheresistancetolowtemperaturecorrosion.109.
What will happen when engine stays in critical speed of 58 - 65
RPM? Ans. Torsional vibration110. What are the causes of L.O. high
temperature? Ans. ~ Fouled cooler ~ Hunting of control valve ~
Insufficient cooling water volume ~ Overloading111. How to detect
starting valve leaks? Ans. ~ Feel over method, by touching the
starting air inlet pipe 112. What are the causes of dirty
lubricating oil? Ans. ~ Prolong blow by ~ Centrifuge not working
properly ~ Too much carbon in suspension ~ Dilution of fuel oil ~
Ineffective sealing on stuffing box (worn out) 113. Identify the
parts of indicator diagram? Ans.Japanese Licensure Examination30
114. What are the symptoms of broken piston ring? Ans. ~ Prolong
blow by ~ Low Pmax ~ Low Pcom ~ High exhaust gas temperature ~
Higher scavenge air box temperature115. How much pressure on air
reservoir? Ans. ~ 25 bar ~ 30 bar116. Name the parts of piston
through connecting rod? Ans. ~ Piston crown ~ Piston skirt ~ Piston
pin bushing ~ Piston pin ~ Connecting rod ~ Connecting rod big end
~ Journal bearing117. What are the causes of positive and negative
propeller slip? Ans. ~ Weather condition ~ Wind force direction ~
Direction of current ~ Condition of hull118. What will be the cause
of scavenging fire?Japanese Licensure Examination31 Ans. If flakes
of burning carbon deposits drop into the oil sludge at the bottom
of the scavenging air box, this sludge can be ignited and if very
combustible material is found here, serious damage can be done
tothepistonrodandscavengeairboxwalls,thelatterpossiblecausing the
reduction in the tensile of the stay bolts. ~ Prolong blow-by ~
Slow combustion in the cylinder, owing in"torrect atomization ~
Blow back through the scavenge air ports or large resistance to
then exhaust system(back pressure)119. What will you do when
scavenge fire happened? Ans. ~ Reduce speed to slow and ask bridge
for permission to stop ~ When the engine stop order is received,
stop the engine and switch the auxiliary blowers ~ Stop the fuel
oil supply ~ Stop the lubricating oil supply
~Putthescavengingairboxfireextinguishingequipmentintofunction ~
Remove any deposits and sludge from all the scavenge air boxes ~
Clean respective piston rods and cylinder liners and inspect if in
order 119. What are you going to observe, when a diesel engine is
ru nning? Ans. ~ Lubricating oil pressure ~ Exhaust gas temperature
~ Jacket outlet/inlet temperature ~ Lubricating oil temperature in
and out ~ Scavenging air pressure and temperature ~ Fuel pressure ~
Cylinder oil glass indicators ~ Turbo charger rpm ~ Load
indicatorJapanese Licensure Examination32 ~ Piston cooling
lubricating oil temperature outlet ~ Exhaust valve opening and
confirm rotation ~ Starting air line pipe if increased in
temperature120. Where is the expansion tank located? Ans. At t he t
op most portion of the engine room How the FCW system of diesel
engine circulate? The cooling water system is divided into two
lines, the jacket line and the cooler line. The standard cooling
med ium used for jacket line is
freshwatertemperaturejacketandcontrolthatvalveforthecontrolscooler
thelineisjacketseawater.coolingTheoutlettemperature by passing or
by passing the fresh water cooler.121. What is mean effective
press? Ans. The positive work done in one cycle of operations by
the gas during the burning period and expansion of the gas. How to
get MEP ~ By finding the area of the banana with the use of PL ANI
METER ~ Area multiplied by the spring consta nt of mechanical
indicat or Or ~ Divide the banana of equal coordinates ~ Measures
the height ~ Add and find t he average or mean height
~Meanheightmultipliedbyspringconstantofmechanicalindicator122. Draw
a crankshaft and show the parts? Ans.123. What is the lower part of
connecting rod? Ans. ~ Crankpin bearing capJapanese Licensure
Examination33 124. What should you do before you start the engine?
Ans. ~ Pre heat the engine ~ Make sure that lubricating oil is p
roperly distributed to its system ~ Turn the flywheel with turning
gear and lubricate cylinder liner ~ Blow off to make sure free of
water in the cylinder125.When you will install a new piston ring,
what will be the positionof it? Ans. The ends of the piston ring
should not be in line or in other words it should be opposite to
each other to prevent blow by or gas escaping to its end 126. What
is max pressure? Ans. ~ The increase in pressure during the burning
of fuel being injected to the cylinder utilizing the heat of
compression127. What are the things to do when approaching the
port? Ans. ~ 12 hours before test steering gear ~ start another
generator for power reserved ~ stand by boiler ~ reduce rpm until
harbor speed ~ stand by engine ~ test main engine ahead and
astern128. What will be the cause of the loose compression in a
cylinder? Ans. ~ Worn out piston ring ~ Worn out linerJapanese
Licensure Examination34 129. What is the maximum P-max for a
cylinder in M/E. Ans. 120-125 bar130. What is the indication of
leaking starting valve of an engine? Ans. Increased in temperature
of starting air pipe 131. What is the thermal efficiency of a
diesel engi ne? Ans. The thermal efficiency of an engine is the
relationship between the quantity of heat energy converted into
work and the quantity of heat energy suppliedThermal Efficiency
=Heat energy converted into work Heat energy supplied132. What will
be the cause of high temperature in one cylinder ofD/E? Ans. ~
Defective fuel oil injector ~ More volume of fuel/rack adjustments
~ Injection timing ~ Leaky exhaust valveSecond Assistant Engineer
(2AE) AUXILIARY MACHINERY 1.Give five parts inside the centrifugal
pump and explain each? Ans.
Forexample,verticalsingle-stagesingle-suctioncentrifugalpump:
Impeller is of the single suction type and the balance holes
provide near the center of the back should serve to cancel the
axialthrustduetothepressurewateronthebackoftheimpeller.Japanese
Licensure Examination35 Pump casing The volute casing is split into
two halves along the vertical plane containing the axis, and the
removal half casing
canberemovedeasilywithoutdisturbingthesuctionanddischarge pipes,
both of which are provided in the stationary half casing.
StuffingboxsealThispumpcanbeprovidedwitheithermechanical seal or
gland packing for stuffing box sealing, which is its important
part. Glandpackingpressureofcarbonfiberisprovidedandsealedbywater
from discharge side.Mechanical packing unbalanced type mechanical
seal is fitted and flushed by pressure water from discharge side
same as gland packing. Bearing - For the upper ball bearing is
furnished to support the rot ating element . Alt hough it is fitted
int o the solid inner case, it
canbetakenouttogetherwiththerotatingelementifthebearing housing cap
is removed. It is grease lubricated. The lower bearing is a line
bearing fitted in the volute casing. For the
bearingmaterial,lubricationisgoodeffectedself-lubricating
bymeansoftheabilityispumpsusedanddischargedpressure water. Impeller
shaft serves as the rotating element of the pump.2.What type of
gear is the first reduction gear pinion? Ans. Helical gear3.List
the main parts of a Centrifugal pump Ans.
-impeller-shaft-bearing,-mouth ring,-volute casing.Japanese
Licensure Examination36 4.Enumerate the causes of pumps low
delivery of water Ans. air leakagespeed too lowsuction lift too
high impeller cloggedimpeller and mouth ring clearance is
bigger5.discharge head too highcavitationdue to high liquid
temperature.What type of pump is main L.O. pump? Ans. Positive
Displacement Screw -type rotary pump6.Howto shut down and overhaul
the centrifugal pumps?Ans. 1)Stop the pump by switching off the
electric motor2)Switch off the circuit breaker and put a notice
pump is to3)be overhauled like warning.Onmotor,that
theelectricdisconnectthe3 -phasewiringanddraw-out the said motor.
4)Draw-out the pump and start dismantling sequentially, e.g.
according to part number and the
like.5)Checkforwearandreplacewithnewspare,checkclearance between
the mouth ring and impeller (should be within the manufacturers
specific ations). Clean parts such as casing, gland and so on.
6)Assemble the pumpand mount with the electricmotor.Perform
coupling alignment to avoid vibration. 7)Connect the electric motor
wiring and start the pump by puttingon the power source. Visu al
check its conditionas well as feeling any abnormalities while
operating.7.What is the specific gravity or relative density of
fuel oil? Ans.Japanese Licensure Examination37 Specific gravity is
the ratio between the density of fuel oil to the density of
standard substance water which is 1.8.Properties of F.O. that cause
damage on auxiliary boiler. Ans. sulfur content9.Ash contentwater
contentDevice use to control flow rate of centrifugal pump. Ans. In
controlling flow rate of centrifugal pump, discharge valve should
be throttled.10.What is the use of gravity disc? Ans. Gravity disc
is responsible for the setting or positioning of the interface at
the outlet of the centrifuge. Various diameter rings are available
for each machine when different densities of oil are used. As
general rule the largest diameter ring which does not break the
seal should be used.11.What causes damage to impellers? Ans. 1.
2.Vibrations3.Corrosion4.12.Over speedingWearsGive the procedures
in starting centrifugal pumps. Ans. Open the air cock at the top of
the casing and turn over the impeller a few times by hand. Close
the discharge valve and prime the pump.Japanese Licensure
Examination38 Start the pump by pushing the motor switch or by
starting its turbine. As soon as impeller began to turn, close the
priming connec tions. When pump is running at full speed, open the
discharge valve gradually. Examine bearings to check operation of
automatic oilers.13.How to stop a purifier? Ans. 1. 2.Stop the fuel
oil feed pump.3.Close the fuel oil inlet outlet
valves.4.14.Manually push the Auto-stop button in the
controllerSecure heater ( steam in and out )What type of pump is
/are commonly used in auxiliary boilers? Ans. Centrifugal
pumps15.Explain the operation of a centrifugal purifier. Ans. The
centrifugal operation of two liquids, such as oil and water,
results in the formation of cylindrical interface between the two.
The positioning of this interface withinthe centrifuge is
veryimportant for correct operation. The setting or positioning o f
this interface is achieved by the used of dam rings or gravity
discs at the outlet of the centrifuge. Various diameter rings are
available for each machine when different densities of oil are
used. As a general rule, the largest diameter ring, which does not
break the seal, should be used.16.How would you increase the volume
efficiency of a centrifugal pump?Japanese Licensure Examination39
Ans. Centrifugal pump volume efficiency can be increased by fully
opening the discharge valve.17.What is fuel oil viscosity, specific
gravity? Ans. Viscosity is the resistance to flow specified by
Redwood Viscosity
inSecondsbeingreplacedbyKinematicViscosityinCentistokes.
Thespecific gravity or relative density is the weight of a
givenvolume of fuel compared to the weight of the same volume of
water expressed as a ratio and measured at a fixed
temperature.18.What type of pump is lubricator pump? Ans. Positive
displacement19.Identify or enumerate the partsof stern
tubeAns.20.Explain how to adjust pump pressureJapanese Licensure
Examination40 Ans. Pump pressure can be adjusted by throttling the
discharge valve, controlling the21.speedWhat is absolute pressure
Ans. Absolute pressure is the true pressure and can be found by the
following formula Absolute pressure Absolute pressure22.= gage
pressure - atmospheric pressure = atmospheric pressure -
vacuumPurpose of stern tube sealing Ans. The purpose of stern tube
sealing is to prevent the ingress of sea water to the engine
room.23.What is white metal Ans. White metal is the most common
type of bearing employed in
slowspeeddieselenginebecauseoftheirabilitytoabsorbparticles of
dirt, ease of manufacture and relative cheapness.24.What is
compound gage Ans. Compoundgageisaninstrumentwhichmeasure
sboththevacuum and pressure.25.What are the safety consideration in
welding job? Ans. ~ wearing of protective clothing ~ proper usage
of welding equipmentJapanese Licensure Examination41 26.Explain the
procedure in starting a F.O. purifier Ans. 1.Open the water supply
valves and make sure that the water supply is on2.Start the
separator3.Be alert on unusual noise and conditions4.Check the
current to the separator motor to ensure that the separator has
reached full speed5.Supply water to form the water seal6.Close the
water feed when water flows out through the water outlet7. 8.Fill
the bowl as quickly as possible9.27.Start the oil feed slowly to
avoid breaking the water sealAdjust to the desired throughputWhat
is a manometer and give an example of its application Ans.
Aninstrumentuse to measurelow pressure readings, canbecommonly
applied in economizer differential pressure. Air cooler and
turbocharger air filter28.What is acceleration Ans. Time rate of
change of velocity29.Enumerate or identify the parts ofJapanese
Licensure Examinationpurifier bowl assembly42 30.What are the types
of pump can be found in the engine room Ans. Centrifugal pump,
screw pump, reciprocating pump, vane pump, axial pump, rotary
pump,31.What is an oil mist detector Ans. An instrument use t o
detect the formation of flammable vapor inside the crankcase32.What
type of metal is used in a propeller Ans. Manganese bronze33.What
is the purpose of safety valve Ans. To relieve the system of excess
pressure34.What is the purpose of gravity tank in the stern tube
Ans. Tomaintainagoodsealingconditionbyprovidingaheadpressure to
give adequate sealing force.35.Explain the opening and closing of
water to the bowl of the purifier Ans. Water in the operating
chamber, builds up a pressure due to centrifugal force (despite
small loss through the drain nozzl e)
whichpushestheoperatingJapanese Licensure
Examinationslidedownagainstthesprings43
beneathit.Assoonastheoperatingslidebeginstomovedownwards, the drain
holes open and the high pressure operating water under the sliding
bowl escapes rapidly. Pressure exerted by
liquidinthebowlforcesthebottomdownandsolidsaredischarged through
the ports. When all of the operating water has drained from the
underside of the sliding bottom and discharge of solids is
complete, then with the solenoid valve closed the operating slid e
is moved back up by the springs to close the drain holes. To raise
the sliding bottom,thechamberunderitmustbefilledwithoperatingwater.
The filling is completed quickly by a short opening of the solenoid
valve. When the chamber is filled and pre ssurized the paring
chamber will start to fill.36.Which has the greater pressure in a
stern tube sealing seawater or L.O. Ans. L.O. has the greater
pressure37.What is the purpose of turning gear Ans. Turn the
flywheel during preheating prior to departure or during the
maintenance of the engine which require positioning of the
piston.38.Locate nozzle in a turbocharger Ans. Nozzle of
turbocharger can be located on the gas side directed towards the
blades of the turbine.39.What is the function of mouth ring Ans.
The mouth ring is installed in the pump to prevent the pump from
axialmovement.Topreventthecontactofcasingwiththeimpeller so as to
avoid wear between the two surface wear ring is also
installedJapanese Licensure Examination44 40.What is flash point
Ans. The lowest temperature at w hich fuel will evolve a flammable
vapor that will41.ignite. In the presence of flame.How do you check
steering gear Ans. The test procedure to be carried out not more
than 12 hours before departure (or weekly on short -voyage vessels)
requires operation
gear,of(whereauxiliaryposition,gear,emergencyapplicable) remote
powerthecontrol supply,following: systems,
ruddermainsteeringbridgesteeringindicator,powerfailure alarms for
remote control systems and also for the steering gear power unit.
While the gear is running, full movement must be checked and a
complete visual inspection must be carried out. The phone or
othermeansofcommunicationbetweenbridgeandsteeringcompartment must
be tested also. While the ship is at sea with the automatic pilot
in prolonged use, manual steering must be tested before entering
busy or restricted
waters.Wheninsuchwatersbothpowerunits(pumpsandmotors) must be
running if simultaneous operation is possible.
Atthree-monthlycontrolandintervalsemergencycommunication;anddrillsoperation(in
cluding withlocalalternativepow er) should be carried out . All
officers are required t o be
familiarwiththesteeringgearandthechangeoverarrangements.
Instructions for changeover must be displayed in the steering
compartment and on the bridge. The various tests and checks should
be logged.42.What is pitch Ans The distance in meter traveled by
the propeller in one revolution if it works in a solid an
unyielding medium43.What is the cause of pressure drop in a cen
trifugal pump Ans. ~ Loss of suctionJapanese Licensure
Examination45 ~ Impeller damage44.Identify the parts of
propeller45.Explain adiabatic expansionJapanese Licensure
Examination46 Ans. A process involving no change in energy during
expansion46. .What is entropy Ans. The measured quantity of
disorderliness47. .What is the common source of leak in stern tube
Ans. Stern tube seal aft side48.What is the purpose of bilge
separator Ans. An equipment that separate the oil content in the
bilge t o the quantit y allow ed by M ARPOL49.Reason why weshould
avoid low speed running on dieselgenerator? Ans. ~ Carbon build up
in the engine/prime mover ~ Low frequency50.What will you check if
one cylinder of your engine is not like others? Ans. ~ Exhaust
temperature ~ Jacket cooling water outlet temperature ~ Fuel pump
rackscale~ Fuel injection timing ~ Fuel injector atomization and
opening pressure ~ Check Pmax and PcomJapanese Licensure
Examination47 51.What is the purpose of gravity disc in centrifugal
purifier? Ans. For purifier operation, the interface for s
eparating light liquid and heavy liquid in the bowl must be held to
within the certain range. Gravity discs of different inner
diameters are used to change liquid outlet diameter, thereby
controlling the interface position.52. Causes of F.O Purifier
abnormal flow? Ans. ~ Inappropriate selection of gravity disc ~
Incorrect oil treating temperature ~ lack of sealing water/Interval
too short ~ Scale formation on operating water device ~ Defective
o-rings, main seal ring and inop erative pilot valve ~ Bowl not
closed ~ Dirty operating water strainer ~ Too much sludge
deposition on disc plates53. What type of pump use in boiler --F.O
system? Ans. Gear pump54. Give the function of evaporator? Ans. ~A
place were the refrigerant boils and changes it states~Absorbs heat
in the space being cooled55. What are the causes of L.O. high
temperature? Ans. ~ Fouled coolerJapanese Licensure Examination48 ~
Hunting of control valve ~ Insufficient cooling water volume ~
Overloading56. How to detect starting valve leaks? Ans. ~ Feel over
method, by touching the starting air inlet pipe57. What are the
causes of dirty lubricating oil? Ans. ~ Prolong blow by ~
Centrifuge not working properly ~ Too much carbon in suspension ~
Dilution of fuel 011 ~ Ineffective sealing on stuffing box (worn
out)58. What is the purpose of spiral gear in a purifier? Ans. ~ It
transmit the power from the motor to the ve rtical shaft ~ Increase
up the speed of the vertical shaft pinion gear59. How much pressure
on air reservoir? Ans. ~ 25 bar ~ 30 bar60. What is non-destructive
test and what is the purpose of it? Ans. Non-destructive test are c
arried out on components, not test pieces. They are use to detect
flaws or imperfections during manufacture or
thosethatdevelopduringservice.Thetestgivenoindicationofmechanical
properties. Visual inspection of surface defects is assisted by
penetrant or magnetic crack detection to find the presence
andJapanese Licensure Examination49 full extent of hairline cracks.
When internal flaws are suspected, use is made of x-rays or
ultrasonic testing. There are special devices for examination of
machine finish. ~ Liquid penetrant methods One type of test uses a
low viscosity liquid, containing a fluorescent dye. The area to be
tested is sprayed or soaked and .@fter time lapsed, to allow for
penetration by capillary action, is wiped dry'. When viewed under
the ultra violet light, any fau lts will be shown up by the glow of
the penetrant in t hem. Anot her t est uses a penet rant containing
as powerful dye. This is sprayed on the suspect area with an
aerosol. Aft er aloowinng time for penet ration, this area is wipe
clean and covered with a liquid which dries to leave the chalky
sediment. The penetrant stains the developer along the line of the
crack.~ Magnetic crack detection
Thistypeoftestissuitableonlyformaterials,whichcanbemagnetized. Aft
er the test , the component is normally de
-magnetized.Amagneticfieldelectric
currentisproducedinthecomponentbymeansofanor permanent magnet
particles are spread on thesurface. Crarks are revealed by a line
of magnetic particles.~ Radiographic inspection X-rays and gamma
rays are used for inspections of welds, castings, forging. Faults
in the metal affect the intensity of rays passing through the
material. Film exposed by the rays gives a shadow photograph when
develop.~ Ultra sonic testing Internal flaw detection by ultrasonic
me ans is in principle similar to
radar.Thereflectedprobebackbyemitshighanyflawsfrequency
inthesoundobject.waveswhichReflectionsarewere alsoreceived back
from the opposite surface. The probe is connected to a cathode ray
oscilloscope, which shows the result in a simple way.61. Where can
you find feed check valve and feed stop valve and give the purpose
of it.Japanese Licensure Examination50 Ans. ~ Feed stop valve A
mounting valve fitted on the water drum intended to isolate the
feed line from the boiler in any even t of maintenance. ~ Feed
check valve A valve on a boiler in conjunction with the feed stop
valve to prevent back pressure on the feed line.62. What are the
causes of troubles in a boiler during operations? Ans. ~ Water on
fuel ~ Dirty atomizer assembly ~ Low fuel oil temperature ~ Dirty
flame eye ~ Clogged strainer63. What are the causes of positive and
negative propeller slip? Ans. ~ Weather condition ~ Wind force
direction ~ Direction of current ~ Condition of hull64. What is the
pressure of fuel oil on main engine and diesel generator? Ans.
Before and Aft er injection pump ~ Main engine 8.0- 9.0 to 320 bar
~ Diesel generator 8.0- 9.0 to 180 bar65. Preparation before
arriving portJapanese Licensure Examination51 Ans. ~ Start
additional generator and put on parallel ~ Prepare boiler ~ 12
hours before test steering gear ~ Main engine test ahead and astern
~ Powered by hydraulic line with coling ~ Prepared mooring lines66.
Where is the expansion tank located? Ans. At the top most portion
of the engine room 67. How the F.C.W. system of diesel engine
circulate? Ans. The cooling water system is divided into two lines,
the jacket line and the cooler line. The standard cooling medium
used for jacket line is fresh water and that for the cooler line is
sea water. The temperature control valve controls the jacket
cooling outlet temperature by passing the fresh water cooler.68.
What are the procedures on how to anneal? Ans. This is usually
accomplished by heating the material to slightly above the
ofthecritical temperature. holding it there until the
temperaturepieceisuniformthroughout.andthencoolingataslowlycontrolled
rate so that the temperature of the surface and that of the center
of the piece are approximately the same.69. How many percent (%) of
carbon content in a Cast Iron? Ans. Cast Iron ~ 2.0% ~ 3%-5% - gray
cast iron Carbon steel ~ low carbon -less than .30%Japanese
Licensure Examination52 ~medium carbon - .30% to .700/0~ high
carbon - .70 to 2.0% (normally the upper limit is 1.40%)70. What
will happen if the centrifugal pump has no pressure? Ans. ~ The
pump tends to overheat and vibrate71. What are the things to do
when approaching the port? Ans. ~ 12 hours before test steering
gear ~start another generator for power reserved~ stand by boiler ~
reduce rpm until harbor speed ~ stand by engine ~ test main engine
ahead and astern72. Give the safety precaution when working in a
high place. Ans. ~Secured permit for working aloft~ Tool box
meeting ~ Prepare tools and secured in a container ~ Use personal
protective equipment ~ Secure harness before doing something ~
Focus on the job73. Checking points in steering gear system? Ans. ~
Hydraulic oil working tanks ~ Motor amperage ~ Leaks of hydraulic
oil ~ Ram cylinders ~ Hydraulic valvesJapanese Licensure
Examination53 74. What are the procedures in paralleling DIG? Ans.
~ Start generator and check if nonnal ~ Check frequency and voltage
~ Switch synchroscope ~ Watch for the direction of pointer fast or
slow ~ Adjust frequency through governor control switc h, balancing
the frequency ~ Close ACB ~ Balance the load if both on IFO through
governor control switch75. What is the indication of leaking
starting valve of an engine? Ans. ~ Increased in temperature of
starting air pipe76. What will be the cause of high temperature in
one cylinder of DIE? Ans. ~ Defective fuel oil injector ~ More
volume of fuel/rack adjustments ~ Injection timing ~ Leaky exhaust
valve77. What is the purpose of air cooler of DIE? Ans.~ To reduce
temperature of scavenge air but above dew point and increase the
density of scavenge air.Japanese Licensure Examination54 Second
Assistant Engineer (2AE) STEAM PLANT 1.What are good
characteristics of good combustion in a boiler? Ans. Proper amount
of oil (sufficient pressure) Proper amount of air Proper
atomization (good mixture of oil and air) Proper oil
temperature2.What do you analyze from boiler water analysis? Ans.
Chloride Content , Alkalinit y, hydrazine, pH -value, conductivit
y3.What do you treat in high alkalinity of boiler water?Ans . Blow
Down and Chemical treatment4.What is a feed water pump? Dearator
feed heater? Ans. Feed Water Pump is the one which forces the water
to enter into the boiler. Deaerator Feed Heater is the one that s
ufficiently preheats the feed water to minimize oxygen5.before
entering the boiler.What is the purpose of the nozzle of impulse
turbine? Ans.Japanese Licensure Examination55 Nozzle is fitted in
impulse turbine to change thermal energy into velocit y. Also t o
direct jet of st eam from no zzles against blades mounted on a
wheel which is converted into work.6.What are the things needed to
have an efficient boiler burning? Ans. Proper amount of airProper
atomization (good mixture of oil and air )7.Coorect amount of oil
(sufficient pressure)Proper oil temperatureName Of Parts And Each
Purpose Ans. 1.CONDENSERwheretheexhauststeamofmainandauxiliaries
are put into. By means of cooling medium like seawater, the steam
condenses and converted into water. 2.8.FEED PUMP forces the feed
water into the boiler.What are the causes of emergency stop in a
steam engine? Ans. -overspeed,-low lub.oil pressure and back
pressure.-9.Whatisthenormalvacuumpressureinasteamturbineatmospheric
condenser? What would cause the press to fa ll? Ans. -Vacuum is
760mmHg (720mmHg and above is considerable)-Air leaks into the
condenser due t o poorly functioning low
pressuresteamsealsortoaleakattheconnectionbetween turbine and
condenser. -Air ejector may not be operating proper ly.Japanese
Licensure Examination56 -Insufficient cooling water. Steam side of
the condenser may be fouled, the waterside may be coated with mud,
or the division plate in the two-pass condenser may be
cracked.10.Steam turbine (function and parts) 1.Economizer - use to
heat feedwater before entering the steam drum utilizing the heat
from exhaustgas2.2nd dearator - remove oxygen and heat
feedwater3.Gland steam seal - prevents steam form high pressure
side of turbine from escaping and prevents air from entering the
low pressure
side4.1stfeedheater-increasethetemperatureofthecondensate
5.Condenser - exhaust steam is converted into condensate6.Main feed
pump - supply feedwater at high pressure to the boiler11.What is
the boiling point of water? Ans. 1000C at atmospheric
pressure12.What are thesafety devices of boiler?Ans. Fuel oil
cut-off for low low boiler water levelFuel oil cut-of for miss-fire
(flame eye system)Fuel oil cut -off at F.D. fan stop and Low press.
At omizingsteam Low control air pressure and Low F.O. pressureLow
Low boiler water level trip13.Fuel oil cut-off at Control room or
Boiler gauge BoardSafety valve for excess steam pressureWhat is the
effect of high alkaline water to a boiler? Ans.Japanese Licensure
Examination57 Scale and caustic embrittlement.14.Steps in starting
boilers. Ans. The uptakes should be checked to ensure a clear path
for the exhaust gases through the boiler; any dampers should be
operated and then correctly positioned. All vents, alarm wat er and
pressure gauge connections should be opened. The superheater
circulating v alves or drains should be opened to ensure a flow of
steam through the superheater. The other entire boiler drains and
blow down valves should be checked to ensure that they are not
closed. The boiler should then be filled to slightly below the
working lev el with hot de-aerating water. The various header vents
should be closed as water is seen to flow from them. The economizer
should be checked to ensure that it is full of water and all air
vented off. The operation of the forced draught fan should be check
ed and where exhaust gas air heaters are fitted they be by passed.
The fuel oil system should be checked for the correct positioning
of the valves, etc. The fuel oil should then be circulated and
heated.15.Small gear found in the steam turbine. Ans. Pinion gears
are used in steam turbine for the purpose of speed
reduction.16.What is an Economizer? Ans.
Theauxiliarysteaminstallationoreconomizerprovidedinamodern diesel
powered tankers usually uses an exhaust gas heat exchanger at the
base of the funnel and one or perhaps to water tube boiler.
Saturated or superheated steam may be obtained from the auxiliary
boiler. At sea it act s as st eam receiver or for the exhaust gas
heat exchanger which is circulated through it. In port it is oil
fired in the usual way.Japanese Licensure Examination58 17.What are
the methods of heat transfer? Ans.
Therearethreemethodsofheattransfer,byconduction,convection and
radiation. -Conduction heat is transferred through solid
body.-Radiation transfer of heat from a source across anintervening
space no material or subject. -Convection transfer of heat through
the motion of the heated matter that is through the motion of the
heated smoke, hot gases and air.18.Types of pressures Ans. At
mospheric pressure t he normal; pressure at open atmosphere which
is equal to 14.7 psi or 1 bar Gauge pressure- actual pressure that
can be read at mostcommon pressure gauges. Absolute pressure- the
sum of gauge pressure and atmosphericpressure.19.What are the
different parts of impulse reaction turbine? Ans. 1.
2.Casing3.Impulse and reaction moving blades.4.Metallic labyrinth
packing5.Steam nozzle6.Water seal7.Turbine shaft8.20. .Stationary
bladesDummy pistonWhat is the color of the flame of the boiler ru
nning in good condition?Japanese Licensure Examination59 Ans. Gold
color flame21.What type of pump is a commonly used in auxiliary
boiler? Ans. Multi stage Centrifugal pumps22.What is the specific
heat of water? Ans. 1 kcal/kg23.What do you do to prevent
flareback? Ans. 1. 2.Well maintained atomizer/nozzle3.24.Alw ays
clear furnace of foul gases before lighting off.Never allow firemen
to light off fires from hot brickwork.What is a brake horsepower?
Ans. The power developed by an engine as measured by the force
applied to a friction brake or by an absorption dynamometer applied
to the shaft or flywheel.25.What is the purpose of a
de-superheater? Ans. De-superheater acts to lower the temperature
of a superheated steam with its temperature just equal or greater
than satur ated steam used for auxiliaries.26.What is the purpose
of corrugated furnaces? Ans.Japanese Licensure Examination60 1.The
corrugation permits a bellow -like action, and so allows expansion
to take place with no strain being imposed on either the boiler
front or the combustion chamber.2.The corrugation offers an
enlarged area and so increases total heat transfer from the furnace
to the surrounding.3.The corrugations serve as stiffeners, which
reinforce the furnace.27.What are the causes of steam turbine
failure? Ans. 1. 2.Improper flow to the condenser.3.Air leaks int o
the condenser.4.Air ejector may not be operating
properly.5.Condensate pump speed my be slow.6.Priming or water
carry over7.Abnormal vibration8.28.Insufficient circulating
water.Insufficient lubricationWhat is the purpose of superheater?
Ans. Itreceivessteamfromthedrypipeandthissteam,beingsuperheated by
combustion gases passing around the outside of the tubes, is
increased in temperature, although the pressure stays practically
the same.29.Given a cutaway isometric view of the steam turbine]
Examinee was asked to identify the following parts: Ans.
a.Condenserb.First reduction gear pinionc.High pressured.Pinion
gearJapanese Licensure Examination61 30.What is thrust bearing?
Ans. Avoidcontactofbladeandcasingbypreventingaxialmovement 31.Give
five boiler mounting valves. Ans. Main Steam Stop valveFeed Check
ValveBlow Down valve32.Safety valvesAuxiliary Steam Stop Valve.In
steam boiler, what are the various test in water boiler? Ans.
Chloride Test , Alkalinit y Test , pH -value, hydrazine conductiv
it y, hardness, phosphate.33.How much calorific value of heat is
needed to heat 0 c
of-100C00C00C+100CIceIceH2OH2OHEAT34.HEATHEATWhat will happen if
boiler backfires? Ans. Accident to human occurs especially when it
was not lit prope rly. Shortens the lifespan of
brickwork.35.Whatisthecolorofflameiftheboilerisrunningingoodcondition?
How about when it is not in good condition? Ans.Japanese Licensure
Examination62 Ayellowishorange,rollingflameindicatesgoodcombustion.
An incandescent whit e flam e with jagged edges indicat es excess
air.36.How does the steam work in a steam turbine? Ans. A high
velocity jet of superheated steam is directly to the nozzles in
impulse turbine or by stationary blades in reaction turbine against
the blade row to prov ide rotational motion of the shaft
whichisconnectedtotheofreducereductiongearleadingtopropeller.37.Whatareprevent
itcausesboilerbackfireandstepsinhowtofrom happening?Ans. Too much
accumulation of unburned fuel and unpurged g ases in the furnace
resulting from inefficient combustion caused by the following: too
low or too high fuel oil temperature (should be
maintainedatpropertemperature),insufficientair -fuelratio(should be
properly adjusted considering the observed flam e) prepurging not
done before flashing (should always be the first step to do before
flashing up the boiler to emit the accumulated gases inside the
furnace), dirty burners and swirler (should be cleaned up38.and
check for proper atomization).What are the causes of high
alkalinity in boiler water? Ans. Presence of scale39.What are
sensible heat, latent heat, and specific heat of water? Ans.
-Sensible heat is the heat that is added to or taken away from a
substance which will cause an increase o r decrease of temperature
as recorded by a thermometer, but will not cause a change of state.
By change of state is meant the change of a solid to liquid, a
liquid to a gas, or vice versa.-Latent heat - is the heat that is
added to or taken away fromasubstancewithoutJapanese Licensure
Examinationanincreaseordecreaseof63 temperature. It does, however,
cause a physical change in the state of the substance such as a
change from solid to liquid, liquid to a gas, or vice versa.
-Specific heat is the ratio of the amount of heat, or the number of
heat units required raising the temperature of a
substanceone-degreetotheamountofheatrequiredraising the temperature
of an equal weight of water one degree.40.What are the causes of
turbine vibration Ans. -41.Insufficient warming -up procedure
Improper clearancesIdentify the parts of steam turbine Ans.42.What
is the normal Ph value of boiler water Ans. 10.5Japanese Licensure
Examination64 43. Causes of the dilution of lubricating oil in a
team turbine? Ans. ~ To much steam pressure on gland sea ling steam
~ Leaking tube bundle of lubricating oil cooler.44. Explain briefly
- good combustion of auxiliary boiler? Ans. However,
furnaceofCompleteatheachievementboilerrequirescombustioncanbeofgoodpracticalcombustionknowledgeobtainedthereisandwithintheexperience.sufficienttime(afunction
of furnace volume), turbulence (provided by the geometry of
theburnerassembly),andatemperaturehighenoughtoprovideignition. Some
aspects are to be observed: ~ Quality of fuel being burn ~
Temperature of fuel ~ Air/fuel ratio or excess air ~ Condition of
oil burners ~ Furnace pressure ~ Wind box pressure Such this
factors are observed and frequent checking of stack gas for
analysis if ever their need to increase air or fuel oil p
ressure.45. Method of testing or checking boiler water? Ans. Test
procedure: CONDENSATE PH TEST ~ Collect 50 ml of condensate sample
and pour into dish ~ Add t hree drops of phenolphthalein. Sample
should t urnpink.~ Add sulfuric acid N/10 drop by drop until pink
color disappears ~ Refer to chart for dosage
adjustmentAMERZINEJapanese Licensure Examination65 ~ Collect 25 ml
of cooled condens"ate ~ Use Amerzine ampoule refill and break the
tip ~ Agit ate for 10 min. for best result ~ Compare color for
dosage adjustmentEXCESS PHOSPHATE TEST ~ Collect and filter cooled
boiler water to 5ml mark on phosphate test tube ~ Add molybdate to
17.5 ml mark ~ Add one brass spoonful of dry stannous chloride ~
Put cork stopper and agitate the solution to stand 3 to 5 mln ~
Compare color with standards in block ~ Refer to chart for dosage
adjustmentPHENOLPHTHALEIN (P) ALKALINITY TEST ~ Collect 50 ml of
cooled boiler water sample and pour into dish ~ Add 4 drops of
phenolphthalein, sample t urns pink ~ Pink color alkaline, no color
P alkalinity zero ~ Add sulfuric acid N/10 until pink color
disappears ~ Note the level of acid in buret convert ml to ppm
using the chart and record results in ppm ~ Keep sample for T
alkalinity test, refer to chart for dosage adjustmentTOTAL (T)
ALKALINITY TEST ~ Add 3 drops of total alkalinity indicator ~ Add
sulfuric acid N/10 until pink color develops ~ Note the level of
acid in buret ~ Total alkalinity results must less than twice the P
alkalinityCHLORIDE TEST ~ Add 10 ml of cooled boiler water into
vial ~ Add 3 drops of phenolphthalein until pink color
developsJapanese Licensure Examination66 ~ Add sulfuric acid N/10
drop by drop until pink color disappear and add one more drop ~ Add
6 drops of potassium chromate, sample t urn to yellow ~ Add Silver
Nitrat e drop by drop and record t he number of drops ~ Note: 1
drop of silver nitrate equal to 10ppmCONDUCTIVITY TEST ~ See meter
instruction ~ Fill the cylinder to 100 ml top mark with cooled
boiler sample ~ Add 2 drops of phenolphthalein and mix ~ Add gallic
acid to pink sample, while mixing, u ntil color disappears ~
Measure temperature of sample and adjust temperature dial ~ Rotate
conductivity dial until both lights remain lighted at the same time
~ Refer to chart to adjust blow down.46. What is mean carryover of
Aux. Boiler? Ans. Consist of particles of leaving the boiler with
steam cause by
highalkalinity,highdissolvedsuspendedsolidandhighchloridecontent.47.
What are steam turbine parts usually come into damage? Ans. ~ Rotor
~ Blades ~ Labyrinth gland ~ Bearings . ~ Nozzle ring ~
DiaphragmJapanese Licensure Examination67 48. Why must we pay
attention when we drain steam in steam turbine. What factors are
observed? Ans. In draining the turbine, steam warming by -pass
valve should be open gradually to avoid hammering and dr ain valve
keep open all the time. ~ Thermal shock must be avoided all the
time ~ Procedure/checklist should be observed during warming
operation with regards to makers recommended procedure ~ Check all
parameters ~ Lubricating oil should be supplied49. What type of
pump use in boiler F.O system? Ans. Gear pump50. What parameters to
be reported when we send lubricating oil for shore analysis? Ans. ~
Lubricating oil running hours ~ Viscosity ~ Sampling point or
origin of oil ~ Type or grade of oil51. In boiler, what does steam
and smoke goes out to the funnel. What reasons? Ans. ~ Tube failure
~ Leaky safety valves or incorrect popping settingJapanese
Licensure Examination68 52. Where can you find the feed check valve
and feed stop valve and give the purpose of it? Ans. ~ Feed stop
valve A mounting valve fitted on the water drum intended to isolate
the feed line from the boiler in any event of maintenance. ~ Feed
check valve A valve fitted on a boiler in conjunctio n with the
feed stop valve to prevent back pressure on the feed line.53. What
are the causes of troubles in a boiler during operations? Ans. ~
Water on fuel ~ Dirty atomizer assembly ~ Low fuel oil temperature
~ Dirty flame eye ~ Clogged strainer54. Give the purpose of nozzle
in impulse turbine? Ans. ~ Serves to convert the high pressure and
high energy of the steam into a high velocity jet of steam with a
reduce pressure and energy content.55. What is gland sealing steam?
Ans. ~ Steam is prevented from leaking out of the rotor high
pressure end and air is prevented entering the low pressure end.56.
How to prevent back fire of boiler? Ans.Japanese Licensure
Examination69 ~Furnace purge~Check leaky fuel valves to t he
burner57. What is the used of economizer in boiler? Ans. ~ Feed
water pre-heater ~ Produce steam during underway58. What is the
Seal packing gland for turbine? Ans. ~ Steam is prevented from
leaking out of the high pressure en d and air is prevented from
entering the low pressure end by the use of glands59. What is the
flow of steam in an impulse turbine? Ans. ~ The high velocity steam
is directed on the blades fitted around the
turbinewheels,thebladesbeingofcur vedsectionsothatthedirection of
the steam is changed thereby imparting a force to the blades to
push the wheel around.60. What will happen if you blow the soot in
the boiler? Ans. ~ Increase in efficiency ~ More steam is produce
~Avoid t ubes overheating61. State the purpose of air heater? Ans.
To heat-up the draft air before entering the furnace by recovering
the heat of the exhaust gas62. How to operate soot blower of boiler
and economizer? Ans.Japanese Licensure Examination70 ~ Raise up
steam as high as possible ~ Drain the steam line until free of
condensate ~For boiler start force draft fan~ Increase draft air
pressure ~ Open steam valve and start soot blow on several
direction63. What do you mean by A.C. C.? Ans. Aut omatic
combustion control64. What is the thermal efficiency of a diesel
engine? Ans. The thermal efficiency of an engine is the
relationship between the quantity of heat energy converted into
work and the quantity of heat energy suppliedThermal Efficiency
=Heat energy converted into work Heat energy supplied65. What is a
blow down valves? Ans. A boiler mounting valve fitted on the bottom
of the water drum use to empty or control the degree of
contaminatio n in a boiler.Second Assistant Engineer (2AE)
REFRIGERATIONJapanese Licensure Examination71 9.What are the three
methods of heat transfer? Give example for each Ans. 1.
2.Convection liquid flow (circulation)3.10.Conduction transfer of
heat from metal to metalRadiation heat from sun
raysNamethefourmostimportantcomponentsofaFreonrefrigeration system.
Ans. 1. 2.evaporator3.condenser4.11.compressorexpansion valveWhat
is an expansion valve and its purpose? Ans.
Anexpansionvalveistheonethatregulatestheflowofrefrigerant entering
the evaporator.12.What happen when the expansion valve is
excessively open? Ans.
Floodingofrefrigerantintheevaporatortakesplace,backpressure would
rise and frost would form on the cylinders.13.Kind of refrigerant
use in a refrigerating system Ans. Boiling temp. R-22 at
atmospheric 410C Boiling temp. R-12 at atmospheric 300C Boiling t
emp. Amm onia at atmospheric 160C7.What are the characteristics of
Freon 12? Ans.Japanese Licensure Examination72 Colorless, odorless,
non -irritating, non-flammable, non-poisonous,
non-explosive,anexcellentsolvent,non -corrosivetometalsordinarily
used in refrigerating units.8.Purpose of condenser in refrigeration
system. Ans. Absorbs the high press. And high temperat ure
refrigerant gases from the compressor and converts its sta te in
liquefied form with the aid of cooling water.9.Kinds of
refrigerants and their properties. Ans. Freon 12 (CCl2F2)
a)Colorless, odorlessb)Non-flammable,
non-poisonousc)Non-irritating, non-poisonousd)Non-corrosive to
metal, excellent solvente)Boiling point 21.60F @ atmospheric
pressuref)Alw ays available in t he marketg)Low power consumption @
higher efficiencyh)Soluble when mixed with oil @ lower viscosity
and pour point.Ammonia (NH3) a)Colorless, corrosiveb)Pungent
odorc)Very soluble in waterd)Boiling point @ atmospheric pressure
280Fe)Combustible or explosive when mixed with airf)Health hazard
due to exposure affect lung tissuesg)Solubility is fairly low when
mixed with airh)Requirehighpowerconsumptionwhichgasneededtocondense
Carbon Dioxide (CO2) a)High specific gravityJapanese Licensure
Examination73 b) c)Non corrosive, non poisonousd)Non explosive and
very safe to healthe)10.Colorless, odorlessBoiling point @
atmospheric pressure 109.30FWhat will happen if there is moisture
in refrigeration system? Ans. There will be a decrease in heat tran
sfer, thereby not achieving the desired low temperature. One
instance is the expansion valve is frosting causing ice, which then
acts as an insulator.11.Explain the cycle of refrigeration system.
Ans. Four major parts involved compressor, condenser, expa nsion
valve and evaporator. The system is composed of two sides, the high
and low-pressure sides. High-pressure side components: From
compressor pressureoutletsidetotheinletcomponents:
Fromoftheoutletexpansion ofvalve.expansionLowvalve tocompressor
inlet.12.Give the different ways of detecting leaking refrigerant?
Ans. 1.A soapy lather spread over joint or pipes will bubbles at
the leak.2.Dampen a piece of litmus paper and run it along piping
joint s, valve stems, et c. An ammonia leak will t urn t he litmus
paper blue.3.A sulfur stick passed along the piping, etc will give
off a dense white smoke on coming in contact with a leak.4.Leaks in
the condenser may be detected by applying litmus paper in
circulating water discharge. The litmus paper turning blue will
indicate a leak.5.For freon, by the use of halide torch. Its normal
blue flame will turn green in the presence of freon13.What is the
cold side of the refrigeration system?Japanese Licensure
Examination74 Ans. The cold side of the refrigeration system is the
evaporator. The refrigerant entering the evaporator at a
temperature lowers than
thesecondarycoolantreceiveslatentheatandevaporates.Later this heat
is given up in the condenser when the refrigerant is again
liquefied. In larger installations the evaporator cools air or
brine. These are circulated in turn a secondary
refrigerants.14.What is the purpose of liquid receiver? Ans.
Theliquidreceiverrefrigerantintheisfittedsystemto togive
caterasufficientforvariousreserveofoperatingconditions. Secondly,
for storage of the refrigerant where it is required to pump over,
i.e., store the charge for maintenance purpose.15.What are specific
heat, latent heat and sensible heat? Ans. Specific heat is the
ratio of thee amount of heat required to raise a mass of a
material, 1 degree in temp. to the amount of heat required to raise
an equal mass of a reference substance, usually water. Latent heat
is the amount heat absorbed or evolved by one mole, or a unit mass
of a substance during a change of stat e at constant temperature
and pressure. Sensible heat the quantity of heat required to change
the temperatureofasubstancebutdoesnotchangeofthesubstance.16.Where
is the warm side of a refrigeration system? Ans. Condenser17.What
would happen if there was water in refrigeration line? Ans.Japanese
Licensure Examination75 Water circulating with Freon tends to
freeze on the regulator causing a build up of pressure on the
evaporator side due to blockage. The machine tends to stop by the
high pressure cut out.18.What safety device will activate to stop
the compressor in the refrigeration system? Ans. Solenoid
valve19.What phenomenon becomes when air mixed with refrigerant? a.
Delivery pressure increase b. Outlet gas temperature Ans.a.) ~ High
discharge gauge reading ~ Jumping of gauge pointers ~ Inefficient
working b.) ~ High cooling outlet temperature of condenser ~ High
refrigerant temperature20. What is the effect if your refrigeration
system has an air? Ans. This is indicated by an abnormally high
refrigerating compressor head pressure readings and possibly by the
presence of small bubbles in the sight glass21.What is short
cycling in refrigeration system?
Ans.Condensercoolantrestrictioncausinghighpressured
ischargecutouts, choked expansion valve giving low pressure22. What
is the hottest part of refrigerant in the refrigeration system?
Ans.Japanese Licensure Examination76 The high pressureside from
whichthe refrigerantis discharged.23. Diagram of refrigeration Ans.
~ Compressor ~ Condenser ~ Liquid receiver ~ Expansion valve ~
Evaporator coil24. Give the function of evaporator? Ans. ~ A place
were the refrigerant boils and changes it states ~ Absorbs heat in
the space b eing cooled25. What is a magnetic valve of
refrigeration system? Ans. ~ Solenoid valve26. In refrigeration,
why during operations is running low pressure at the suction side?
Ans. The expansion valve tends to control the degree o f superheat
in the evaporator, were the refrigerant boils and absorbs heat in a
lower pressure. 27. What is a liquid floodingin refrigeration
system?Ans. Liquid refrigerant enters the suction sude of the
compressor28. What are the safety device that are fitted in a
refrigeration system? Ans. ~ Lubricating pressure switchJapanese
Licensure Examination77 ~ High pressure switch ~ Lubricating oil
pressure switch29. What is flaring tool? Ans. Used for tubing
connections in enlarging the inside diameter of th e tube to a
tapered shape.Second Assistant Engineer (2AE) ELECTROTECHNOLOGY
1,How are voltmeter and am meter connected in the circuit? Ans.
Voltmeter - connected in parallel Ammeter - connected in
seriesJapanese Licensure Examination78 2,What is the function of s
pace heaters for motors? Ans.
Maintainsthetemperatureofmotorwindingstoavoidtheformation of
moisture.3.What is Ohm slaw? Ans. Ohm's law states that the current
o