Orals EKM With Ans

7/30/2019 Orals EKM With Ans

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1. Procedure for Overhaul of A/E.

a. Chec whether all tools and spares are available or not.

b. If so, then start the Stand by generator.

c. Chec all parameters are normal.

d. Now share the load with the help of synchroscope.

e. Again chec all the parameters are within normal range.

f. Put full load on the Stand by generator.

g. Stop the generator on which wor has to be carried out.

h. Put MEN AT WORK tag.

i. Shut the air starting valve, fuel oil inlet & outlet valves and isolate the system.

j. Let lube oil priming pump run for half hour after then stop it.

. Drain the jac et water.

l. Remove the cylinder head cover.

m. Remove high pressure pipe.

n. Ta e out the injector using its tool.

o. Open the roc er arm bolts & remove it from its place.

p. Remove the Jac et water outlet pipe.

q. Disconnect the scavenge & exhaust manifold from the cylinder head.

r. Open the cylinder head bolts using the Torque spanner or hydraulic jac (As provided on your vessel).

s. Chec the lifting gear (Crane & chain bloc , Eye bolt, etc.)

t. Lift the cylinder head & put it at a suitable place.

u. Open the cran case door.

v. Bring the piston to TDC position & attach eye-bolt on it and Attach hoo of chain bloc to it.(Before bringing Piston to TDC, the top part of liner needs tobe cleaned)

w. Bring the piston to BDC and open the bottom-end bolts & remove bottom end bearing.

x. As load of piston is now on Lifting gear, so ta e it out & put it on the piston stand.

y. Remove the piston rings using ring extractor.

z. Remove the circlip from the gudgeon pin & ta e out the gudgeon pin, so connecting rod can be ta en out.


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1. How do you decide if piston rings should be changed or not?

a. Butt clearance increased then its normal range.

b. Axial clearance increased.

c. Visual condition of piston ring.

1. How you chec lifting gear.

a. Chec the condition of wire rope & grease it.

b. Chec the visual condition of chain.

c. Chec the limit switches in the forward, aft, Port & starboard direction arewor ing.

d. Chec that emergency button is wor ing.

e. Chec the visual condition of the insulated cover is satisfactory.

f. Chec overload trip is wor ing satisfactorily.

g. Chec the visual condition of chain bloc , no crac s should be there.

h. Chec that safety latch is there on chain bloc .

1. What chec s on piston and liner.

a. Piston:-

i. Chec the piston for any crac s.

ii. Chec the piston top profile.

iii. Chec for any carbon deposits.

iv. Chec the butt clearance, axial & radial clearance.

1. What to do if valve seat damaged?

1. Chec s on cran case inspection in Main Engine?

Safety Precautions:

1. Inform bridge and Chief Engineer.2. If in port, ta e Immobilization certificate.3. Get propeller clearance from the duty officer.4. Shut off starting air valve.

5. Put Men at Wor tag.6. Stop lube oil pump.7. Indicator coc s to open.8. Turning gear should be engaged9. Wear proper PPE, Shoes & helmet.

10. No na ed lamp to be ta en inside.11. Open the cran case door ta ing it as a shield.12. Ventilate the cran case door properly.13. No items should be inside the poc ets of boiler suit.


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Inspection:

a. Chec the condition of lube oil, for any smell, discoloration, degradation.

b. No paint parts to be there in the sump.

c. Turn the engine to BDC and under stuffing box area for any blac oil.

d. Chec piston rod for any scoring & roughness.

e. Chec piston palm bolts & loc ing.

f. Chec the guide shoes and the area around it.

g. Chec guide shoe end cover bolts.

h. Chec X-head bearing general condition.

i. Chec all bearing for white metal.

j. Chec oil pan area of every unit for any sludge formations, bearing metals &foreign particles.

. Chec top & bottom of connecting rod bolts, nuts & loc ing device.

l. Chec the axial movement of bottom end bearing.

m. Chec slippage of web & journal by reference mar s.

n. Chec the teeth of transmission gear.

o. Chec the tightness of chain drive.

p. Chec c/case relief door spring tension, wire mesh & sealing ring.

q. Chec & clear the O.M.D sampling pipes.

r. Start the lube oil pump & chec flow .

s. Chec c/case door sealing condition & close it c/case door.

t. Ma e sure no foreign matter or tools should be left inside the c/case.

1. Tappet clearances why plus how to chec .

Tappet clearance is ta en to ensure positive closing of the valve & for thermalexpansion of the valve.

Ta ing all safety precautions.(See Ans. 1)

Ma e sure the piston is on TDC.

i. From the mar ing on the flywheel.

ii. From the fuel cam.

iii. Push rod should be free.

Ma e sure the engine has cooled down.


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Loosen the loc nut of the roc er arm.

Now adjust the tappet clearance between the roc er arm & valve stem by tightening or loosing the nut below the loc nut.

If tappet clearance is less:

i. Valve will open early & close late

ii. Air induced through inlet valve may lea out. So, less air for combustion.

iii. Power will be reduced.

iv. Fuel consumption will increase, engine may become unbalanced, exhaust temp.will be very high.

v. In worst condition, valve may remain open, resulting in loss of compression pressure, burning of exhaust valve, T/C fouling will increase.

If tappet clearance is more:

i. Valve will open late & close early.

ii. Lesser heat energy to T/C, so reduction in scavenge air & hence power.

iii. No proper removal of gases.

iv. Hammering of valve stem-may cause damage to valve stem.

1. What to chec if Engine is not starting on air and fuel

Engine not starting on Air:-

a. Low air bottle pressure or air line valve may be shut.

b. Air bottle isolating valve or automatic valve or distributor not functioning.

c. Control air valves faulty or less control air pressure.

d. Start air automatic valve jammed.

e. Turning gear engaged.

f. Reversing has not ta en place completely.

g. Control valve for fuel or start is not in its end position.

h. Bursting diaphragm on start air line damaged.

i. Fuel lever on maneuvering stand not on remote mode.

j. Auxiliary blower not running or not on auto mode.

. Emergency stop has activated.

l. Interloc is operated.

m. Cylinder air start valve defective or stic y.

n. Piston not in firing mode.


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Engine not starting on fuel:

a. Less fuel in service tan .

b. Fuel filter is choc ed.

c. Fuel supply pumps not delivering required pressure. Or fuel pump tripped.

d. Fuel level on local maneuvering stand, is not on remote stand.

e. Fuel rac stuc .

f. Fuel pump malfunctioning, jammed plunger.

g. Injector nozzle needle stic ing or holes bloc ed.

h. Compression pressure is too low due to bro en piston ring or exhaust valve not closing properly.

i. Fuel pump relief valve lea ing.

j. Start air pressure insufficient to turn the engine fast enough.

1. What to chec if Engine is not ta ing load.

1. What precautions to ta e to start A/E After overhaul.

a. Water tightness to be chec ed.

b. Air to be removed from jac et water outlet line.

c. Priming lube oil pump to run before starting the engine.

d. Chec the lube oil level.

e. Chec the flow of lube oil.

f. Blow through the engine before starting.

1. How to change purifier to clarifier.

Remove the gravity disc.

1. How to select damn ring for purifier.

From the monogram provided with manual, which is drawn with respect to viscosityof oil & which size damn ring to be used.

If monogram not there, then

a. Chief Engineers experience will come into use.

b. Hit & trial method to be used.

i. First use the largest gravity disc and whether oil is overflowing, if so, then use small size gravity disc and follow this process until oil stops overflowing.

1. What to chec if purifier over flowing.


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a. Size of gravity disc.

b. High throughput.

c. Temperature of the oil.

1. How to stop Aux Engine if not stopping by stop handle.

a. Pull the fuel rac to zero position.

b. Operate any trip.

1. Charging gas in Dom Fridge?

1. Close the receiver outlet valve and collect the gas in the receiver.2. Chec the liquid level, if it is below L/3, Charging is reqd.3. Chec the weight of the refrigerant bottle & eep it upright.4. Connect the charging line to the connecting point and eep it loose.5. Open the bottle valve slightly and purge the line into the collecting cyli

nder and then tighten the connection.6. Open the charging valve and fully open the bottle valve.7. Chec the liquid level in the sight glass and ma e sure no air bubble pres

ent in the system.

8. Close the charging valve and the bottle valve.9. Open the receiver outlet valve & start the compressor.10. Carry out let detector test.

1. Charging oil in Domestic fridge.

Method 1.

1. Mostly ships have hand p/p provided which develop more pressure than the inside pressure.

Method 2.

1. Reduce the L.P Cut out setting.2. Dip the pipe inside the c/case of compressor.3. Run compressor, vaccum will develop.4. So, compressor will start suc ing the oil.5. Ma e sure the pipe is diped fully, because it has got chances of suc ing a

ir.6. If air gets in, then purge it in a separate bottle after charging of oil g

ets completed.

1. What to chec if Room temp (one room) not coming down?

-

1. What to chec if all room temp not coming down?

- Room doors not shut properly.

- Room insulation is bad.

- Air in system.

- Room fans not running.


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- Evaporators frosted.

- Compressor not wor ing satisfactorily, unloader defective, valve lea y, ringsdamagd.

- Expansion valves cho ed/ malfunctioning.

- Evaporator bloc ed.

1. What to do if dom. fridge is short cycling/

- L.P Cut out is defective.

- L.P Cut out setting not correct, too low difficult for Cut In.

- Lesser gas flow

1. Less gas in system.2. Drier Cho ed.3. Expansion valve filter cho ed or Expansion valve Malfunction.4. Evaporator Cho ed.5. Compressor valves lea ing.

Actions:-

a. Chec L.P. Cut out setting, Cut out pressure OK.

b. Chec flow of gas by seeing sight glass which should show full flow of refrigerant.

c. If no full flow- Either less gas or drier choc ed, Clean the drier.

d. Chec level in receiver, if low, then charge gas.

e. Expansion valve filter cho ed, then clean it.

f. Expansion valve malfunctioning- Change it.

g. Evaporator cho ed- Blow-thru evaporator with nitrogen.

1. Overhaul of centrifugal pump.

1. Changing pipe join below floor plate without removing pipe.

1. Can not pump out bilges. What chec s? What to do if pipe holed?

1. Chec Sounding of bilge tan .2. Chec Bilge tan outlet v/v open or not.3. Chec P/p inlet v/v open or not.4. Chec p/p wor ing properly.

5. If vaccum developing that means hole in pipeline.

If pipe is holed:-

1. Carry out Vaccum test by closing inlet valve & opening outlet /v.2. If hole is between the inlet v/v and p/p, vaccum will develop, now remove

top of v/v and put water.3. If hole is in between Inlet v/v and bilge tan outlet v/v, then again put

S.W


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1. Boiler press coming up and gone above the safety valve lifting pressure. What to do?

Use the easing gear to release the excess pressure.

1. Bridge informs steering not responding. What to do?

1. Air comp bumping clearance how to chec and adjust.

1. Start the Stand by compressor.2. Stop the compressor whose bumping clearance has to be ta en.3. Isolate the system.4. Put Men at Wor tag.5. Loosen the cylinder head bolts and lift it.6. Measure the diameter /size of the lead ball.7. Bring piston to TDC and put lead ball on centre of it.8. Now, put the cylinder head and tighten it to required torque.9. Now, again loosen the cylinder head bolt and remove the ball.

10. Measure the size of the ball.11. The difference between the initial size and final size is the bumping clea

rance.

It can be adjusted by either putting a thinner gas et or putting shim on top half of the bottom end bearing.

1. Removal of bro en stud.

First drill the stud little bit & then use Thread extractor which has left handthread.

1. Bridge informs lot of smo e from funnel what to do?

1. Reduce load on engine.2. Chec purifier operating alright/ reduce throughput to have better purific

ation.3. Drain water from settling & service tan .4. Chec scavenge air temperature & adjust if reqd. .

5. Soot blow the economizer.6. Ensure, fuel oil end heater outlet temperature proper corresponding to attain viscosity at the point of injection.

7. Chec , if any particular Exhaust temperature is higher than others, if so,then stop the engine, Change the injector with a spare overhauled injector.

8. Chec all fuel pump timings are correct or not.9. Dismantle and carry out overhaul of T/C.

10. Send fuel oil for Laboratory analysis.

Reasons:

1. Improper combustion.2. Burning of carbon particles collected at EGE.

3. Overloading of engine.4. Inform bridge & Chief engineer.5. Raise engineers call/emergency alarm.6. Before starting bilge pump note down the position of vessel & time of star

ting.7. Other engineers will in between try to locate the hole or burst of pipe an

d repair.8. If ingress of water very high, start another pump.9. Reduce the engine r.p.m.

10. Change over main s.w suction to emergency bilge suction.


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11. If level is still coming up try to protect the motor from short-circuiting, if required start emergency bilge suction valve.12. If situation is not coming in control, prepare lifeboat for lowering.

1. Flooding in Engine Room what to do?

1. What chec s to be made on Aux Engine when running?

Chec s:

1. Chec scavenge air temperature.2. Chec Exhaust gas temperature.3. Chec r.p.m4. Chec load on A/E.5. Carry out pea pressure.6. Chec for any abnormal noise or vibration.7. Chec jac et water inlet & outlet temperature.8. Chec Lube oil temperature & pressure.

1. During running Main Engine stops. What chec s?

1. Chec whether Emergency stop operated by any personnel.2. Chec level of fuel oil in Service Tan .3. Chec whether purifier wor ing properly.

4. Chec whether water is there in Service tan due to improper purification.5. Low lube oil pressure trip operated, Chec L.O P/p developing correct pressure.

6. Control air trip operated, Chec control air pressure.

1. Boiler blow bac what to do and reasons?

Reasons:-

1. Insufficient pre-purging.2. Blower not wor ing.3. Accumulation of oil.4. Lea y solenoid valve.

5. Dripping of burner.

Action:-

1. Stop the firing.2. Chec the condition of burner, if it is dripping, then overhaul is require

d.3. Do the inspection of the furnace.4. Carry out sufficient pre-purging.5. Start the boiler on Auto mode.

1. Boiler extinguishes what to do?

1. Accept the alarm.2. Find out the reason for extinguishing:-3. if too low water level alarm came, then chec pump is developing correct p

ressure or not , its is wor ing properly.4. If Tripped on high pressure, let the steam pressure come down.5. Fuel oil low pressure alarm , then chec functioning of fuel pump, oil in

service tan .6. Fuel oil low temp. alarm, then use the heater.7. Flame failure trip, then clean flame eye, chec the furnace & overhaul the

burner.


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1. Overhaul of fuel valve?

Safety Precautions:-

a. Chec whether all tools and spares are available or not.

b. If so, then start the Stand by generator.

c. Chec all parameters are normal.

d. Now share the load with the help of synchroscope.

e. Again chec all the parameters are within normal range.

f. Put full load on the Stand by generator.

g. Stop the generator on which wor has to be carried out.

h. Put MEN AT WORK tag.

i. Shut the air starting valve, fuel oil inlet & outlet valves and isolate the system.

j. Let lube oil priming pump run for half hour after then stop it.

. Remove the loc nut of the high pressure pipe.

l. Now, remove the high pressure pipe.

m. Ta e out the fuel injector using it tool.

n. Put it on the testing it.

o. Chec the lifting pressure, atomization, pressure falling steadily, drippingof oil.

p. Now, ta e out the injector from the testing it, put in a diesel oil & cleanit.

q. Ma e sure the wor shop table should be clean, no rags or jute to be there.

r. Put the injector on the vice and tighten it.

s. Loosen the loc nut of the injector.

t. Now loosen the compression nut to release the spring pressure, then ta e outthe spring.

u. Open the cap nut and ta e out the needle and guide.

v. Put the parts on the cleaned table.

w. Chec the condition of spring by dropping on the floor plate, it should jumpand also chec it by tightening in the vice and then releasing. The difference in the length,no crac s to be there.

x. Chec visually needle, there shouldnt be any scoring mar s because it is madeof Nitrite material.


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y. Try to insert the needle inside the guide at angle of 45degree, the needle should on its own weight.

z. Chec the size of injecting holes by using Go or No go gauge.

i. If go gauge is going then hole size is OK.

ii. If no go gauge going, then it means the size has increased, then nozzle needs to be changed.

iii. Now assemble the injector and do the lifting pressure setting on test it by adjusting the compression nut.

iv. After this chec the injector again for its lifting pressure, atomization, steady fall of pressure and dripping.

1. How pressure testing of Globe Valve is done?

a. Blan one side of valve and put water from the other side, chec for any leaage.

1. Overhaul of a cylinder head & what all to chec ?

1. Overhaul of Inlet & exhaust valve of aux.enine?

1. Function of Roto-Cap in valves & how it is overhauled?

a. It helps to rotate the valve during operation with the help of the exhaust gas, so as less wear occurs and stress doesnt comes only at one point.

1. What is dye-pentration test, why is it done & how is it done?

Dye-Penetration test is a lea test carried out to now about the lea age/ cracin any part.

In it, first the part or unit is cleaned, paint is removed where the crac is suspected, then it mar ed on the unit. If water is coming, then colour will change

, which shows the crac .

1. How al alinity test is carried out?

1. Ta e 200 ml water sample in the stoppered bottle.2. Add one P.Al alinity tablet & sha e or crush to disintegrate.3. If P.Al alinity is present the sample will turn blue.4. Repeat the tablet addition, one at a time, until the blue colour turns to

permanent yellow.5. Count the number of tablets used and carry out the calculation:

P.Al alinity, ppm CaCO3 = (Number of tablet x 20) -10

f. Record the result obtainied on the log sheet provided, against the date on which result was obtained.

1. Why water is ept heated in hot-well?

1. To prevent oxidation2. To avoid thermal stress on boiler.

1. Position of Unloader in AC & Ref. compressor ?


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Unloader in AC & Ref. compressor is located near the suction valve of the compressor.

1. What all clearances ta en in centrifugal pump?

1. The wear ring & impeller.2. The wear ring & the casing.3. Shaft and the bush.

1. Why centrifugal pump is not self priming?

Because of the churning effect it is not be able to remove air positively as mass of air is relatively zero.

1. What is the position of bearing in centrifugal pump?

Near the impeller.

1. What is the position of piston when ta ing bearing clearances

- Main Bearing Clearance --B.D.C

- Bottom End bearing clearanceB.D.C

- Cross-head bearing clearance.B.D.C

1. How to overhaul gear pump and centrifugal pump? And clearance to ta e.

1. How to ta e out connecting road?

1. How to test cylinder head relief valve onboard?

1. During maneuvering Bursting disc of air compressor get damaged, what action to ta e?

1. Inform the bridge about the problem and to give lesser ic s.2. Start the stand by compressor.

3. Isolate the compressor whose bursting disc is damaged.4. Change the bursting disc, if available onboard.5. If Not available, then let the S.W go into the E/room bilges, otherwise Fr

esh water cooled , then join a flexible hose and put into the expansion tan .

1. How will you test the cran case relief door?

The testing of the C/case relief door is done at shore.

1. Reasons of Purifier overflow?2. Procedure for doing boiler blow down?

Precautions

1. Ensure nobody is near the ship side blow down valve.2. Not to be carried out in drydoc or alongside.3. Valve sequence to be followed.4. Boiler shouldnt be left unattended during blow down.5. Monitor the end of blow down. Long blow down to be avoided.6. Dont blow down to the E/room bilges.

Procedure


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1. Ship side valve 1 is opened followed by valve 2.2. Valve 2 is NR which is fully opened to avoid cutting off seat.3. Rate of blow down controlled by Valve 3.4. For scum blow down valve 4 & 5 are used.

1. Action to be ta en, if chloride content is excess?

Blow down of boiler to be carried out.

1. How to blow through boiler Gauge Glass?

Procedure:

1. Ma e sure drain line is clear2. Close the steam outlet valve.3. Close the water outlet valve.4. Open the drain valve.5. Open the water out valve & let water flow thru it and close the valve afte

r blowing down with water.6. Open the steam out valve and blow thru with steam.7. Close steam valve.8. Close the drain valve.9. Now, open the water side valve.

10. Let water fill up 3/4th gauge glass.

11. Open the steam valve slowly.

1. How to tighten boiler gauge glass after overhauling?

Procedure of tightening:

1. First tighten all the bolts by hand slightly without putting any pressure.2. Now, tighten bolt 1 & 2 equally. Then 3 & 4.3. Tighten bolt 5 & 6. then 7 & 8 equally.4. Tighten bolt 9 & 10.5. Now again tighten 7 & 8. Then 5 & 6.6. Tighten bolt 3 & 4. then 1 & 2.

Or you can say we first tighten outward bolts of both side & then inward side.

Then we move in opposite steps. i.e. tight inward bolts & then outward bolts.

Differences betwn Watercooled and Oilcooled piston

W - High specific heat capacity therefore removes more heat per unit volume

O - Low specific heat capacity

W - Requires chemical conditioning treatment to prevent scaling

O - Does not require chemical treatment but requires increased separate and puri

fication plant

W - Larger capacity cooling water pump or separate piston cooling pump and coolers although less so than with oil

O - Larger capacity Lube oil pump, sump quantity and coolers

W - Special piping required to get coolant to and from piston without lea

O - No special means required and lea age not a problem with less ris of hammer


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ing and bubble impingement.

W - Coolant drains tan required to collect water if engine has to be drained.

O - Increased capacity sump tan required

W - Pistons often of more complicated design

O - Thermal stresses in piston generally less in oil cooled pistons

W - Cooling pumps may be stopped more quic ly after engine stopped

O - Large volumes of oil required to eep oxidation down and extended cooling period required after engine stopped to prevent co ing of oil

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Orals EKM With Ans