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МЕТОДИЧЕСКОЕ ПОСОБИЕ
К практическим занятиям по дисциплине
«Английский язык» для студентов IV курса
специальности 0905
«Эксплуатация судовых энергетических установок»
дневной формы обучения
Севастополь 2017
УДК 629.123+656.61.052
Рабочие неполадки I= MALFUNCTIONS
Методическое пособие к практическим занятиям по дисциплине «Английский язык» для студентов IV курса специальности 0905 «Эксплуатация судовых энергетических установок» дневной формы обучения / Сост. ст. преп. Мороз Ю..А. – Севастополь: Изд-во СевГУ, 2017 – 40 с.
Целью данного методического пособия является привитие навыков чтения и понимания литературы по специальности, обучения активному владению языковым материалом, ведению беседы на английском языке в пределах рассматриваемых тем и специальности студентов, которые являются основой для дальнейшего совершенствования навыков беседы на профессиональные темы.
Методическое пособие утверждено на заседании кафедры ПРГЯ.
Допущено учебно-методическим центром в качестве методического пособия.
Рецензент: Михайлова Е. В. доцент кафедры Романской и германской филологии Севастопольского государственного университета.
СОДЕРЖАНИЕ
Введение………………………………………………………………………………………….4
Test yourself……………………………………………………………………………………..37
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Приложение………………………………………………………………………………….…39
Библиографический список……………………………………………………………………41
ВВЕДЕНИЕ
Методическое пособие предназначено для студентов IV курса специальности «Эксплуатация судовых энергетических установок» и состоит из 8 уроков.
Целью данного методического пособия является привитие навыков чтения и понимания литературы по специальности, обучения активному владению языковым материалом, ведению беседы на английском языке в пределах рассматриваемых тем и специальности студентов, которые являются основой для дальнейшего совершенствования навыков беседы на профессиональные темы.
В каждом разделе даны: тексты для просмотрового чтения, список слов и выражений для запоминания, которые рекомендуется использовать в своей речи; примечания к тексту, объясняющие, как правило, трудно переводимые словосочетания; лексико-грамматические упражнения, цель которых отработать специальную лексику; тест для проверки знаний студентов; в приложении дан краткий список синонимов.
Система упражнений к урокам включает в себя упражнения, направленные на:
- развитие навыков различных видов чтения;
- усвоение специальной лексики;
- формирование специальных навыков профессиональной устной речи (диалогической и монологической);
- развитие навыков письма.
При составлении упражнений использован коммуникативный принцип, и, следовательно, ситуативность, которые могут возникнуть на судах смешанного плавания.
The More You Know Your Machine, The Better It Will Perform.
An accident is a specific, unpredictable, unusual and unintended external action which occurs in a particular time and place, with no apparent and deliberate cause but with marked effects.
Standing Orders
When watch engineers are to call the chief engineer
1. IF any fire, no matter how small, is discovered in any machinery space or in any other part of the ship.
2. IF the generator trips off (выключаться, отключаться) the line or any difficulty is experienced in maintaining constant frequency, voltage or load requirements.
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3. IF the temperature of the generator stator or rotor increases suddenly or exceeds the prescribed limits.
4. IF any difficulty is experienced in maintaining a steady water level in boilers or any difficulty in maintaining satisfactory operation of the boiler feed pump or water level regulations.
5. IF there is any increase in consumption of make-up feedwater (питательная вода).
6. IF there is any seawater leak in main condenser, auxiliary condenser or other system that is contaminating the boiler feed system.
7. IF any difficulty is experienced with water in fuel or loss of fires.
8. IF pressure drop across generator, superheater or economizer tube banks (пучок трубок) exceeds limit marked on boiler front.
9. IF any local or general overheating of boiler casing is discovered.
10. IF superheat temperature should show abnormal increase that is not corrected by adjustment of excess air.
11. IF any difficulty is experienced in keeping bilges pumped dry.
12. IF any air, oil, fuel, water or steam leaks occur that are other than minor.
13. IF any difficulty is experienced with plugged or choked sea chest (кингстонная коробка).
14. IF any leak is discovered in any sea connection valve or fitting, especially in the body (корпус клапана), bonnet (крышка или колпак) or joint (соединение или разъем).
15. IF bridge requests speed increase requiring a greater steam flow to H.P. turbine than the limit set by chief engineer’s standing orders.
16. IF any unusual, concentration of dirt or foreign matter, especially particles, is discovered in the main lubricating oil strainers.
17. IF any abnormal temperature rise is noticed in the main turbine, reduction gear, line shaft or turbo generator bearing.
18. IF any unusual vibration is noticed, especially in the main propulsion system or turbo generators.
Exercise 5. Translate the sentences into Russian.
1.When taking over the underway watch the engineer is considered the oncoming watchkeeper and at such time he shall obtain all relevant information from the engineer that he is relieving and that is called the offgoing watchkeeper.
2. Both engineers shall make a joint inspection round of the machinery spaces, note the condition of machinery, equipment, piping and bilges, take fuel oil meter readings and standard entries in the engineer’s log.
3.The watchkeepers shall maintain cleanliness in machinery spaces, take precautions to avoid fire hazards, clean strainers and filters, discharge separators, change-over from running to stand-by machinery components.
4. During the watch watchkeeper will check operating pressures and temperatures, liquid levels and flows, running machinery bearing for overheating, piping for leakage, plant components for unusual (excessive) noise or vibration, alarms and automatic control devices for proper functioning, availability and operable condition of fire-fighting and safety equipment.
5. Are there any problems with fuel and lube oil pipes, tubes or hoses? – There are no leaks on piping, all joints are tight.
6. Have you taken the pressure gauge reading? – Yes, I have. Circulating oil pressure is 3.5 kg/cm2, which is above normal, valve gear lube oil pressure is 1 kg/cm2, it’s normal and cooling water pressure is 0.5 kg/cm2, I think it’s below normal.
7. What is the sounding in the port fresh water tank? – Fresh water sounding is 6.5 meters.
8. What does the order “Stand by engine” mean? – It means that engine room personnel are fully ready to manoeuvre.
9. Do you know the standard engine orders? – They are Full/Half/Slow/ Dead slow ahead or astern; Emergency full ahead or astern.
10. Is there any break down of machinery? – Blackout in boiler room.
Exercise 6. Translate the sentences into English.
1.Вахтенный моторист подчиняется непосредственно вахтенному механику и выполняет распоряжения под его присмотром.
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2. Моторист ведет контроль над работой порученных ему действующих технических средств, немедленно докладывает вахтенному механику о замеченных неполадках в работе технических средств и принимает меры к их устранению.
3. Вахтенный моторист поддерживает в машинном отделении чистоту и порядок.
4. Перед запуском любого механизма необходим его наружный визуальный осмотр. 5.Вахтенному мотористу без разрешения вахтенного механика категорически запрещается производить работы, связанные с вводом и выводом действующего технического средства, за исключением случаев, связанных с угрозой жизни.
6. Я еще не проверил те механизмы на правильность работы.
7. Он проверил рабочие давления и температуры, а также подшипники на перегрев.
8. Моторист действует в соответствии с распоряжениями вахтенного механика.
9. Вы можете заменить неисправное оборудование? – Да, но только в присутствии вахтенного механика.
10. Все произведенные замеры в топливных цистернах и снятые показания приборов должны быть занесены в журнал машинного отделения.
Watch the video “Vessel Safety Inspections” and discuss the following topics:
[https://www.youtube.com/watch?v=7ZVfSt7NGZs]
Application of calipers
A caliper is a device used to measure the distance between two opposite sides of an object. A caliper can be as simple as a compass with inward or outward-facing points. The tips of the caliper are adjusted to fit across the points to be measured, the caliper is then removed and the distance read by measuring between the tips with a measuring tool, such as a ruler.
It is used in many fields such as mechanical engineering, metalworking, forestry, woodworking, science and medicine.
A caliper must be properly applied against the part in order to take the desired measurement. For example, when measuring the thickness of a plate a vernier caliper must be held at right angles to the piece. Some practice may be needed to measure round or irregular objects correctly.
Accuracy of measurement when using a caliper is highly dependent on the skill of the operator. Regardless of type, a caliper's jaws must be forced into contact with the part being measured. As both part and caliper are always to some extent elastic, the amount of force used affects the indication. A consistent, firm touch is correct. Too much force results in an underindication as part and tool distort; too little force gives insufficient contact and an overindication. This is a greater problem with a caliper incorporating a wheel, which lends mechanical advantage. This is especially the case with digital calipers, calipers out of adjustment, or calipers with a poor quality beam.
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Simple calipers are uncalibrated; the measurement taken must be compared against a scale. Whether the scale is part of the caliper or not, all analog calipers—verniers and dials—require good eyesight in order to achieve the highest precision. Digital calipers have the advantage in this area.
Calibrated calipers may be mishandled, leading to loss of zero. When a calipers' jaws are fully closed, it should of course indicate zero. If it does not, it must be recalibrated or repaired. It might seem that a vernier caliper cannot get out of calibration but a drop or knock can be enough. Digital calipers have zero set buttons.
Vernier, dial and digital calipers can be used with accessories that extend their usefulness. Examples are a base that extends their usefulness as a depth gauge and a jaw attachment that allows measuring the center distance between holes. Since the 1970s a clever modification of the moveable jaw on the back side of any caliper allows for step or depth measurements in addition to external caliper measurements, in similar fashion to a universal micrometer.
Exercise 6. Answer the following questions.
1) What is caliper? Give a definition
2) In what fields calipers are used?
3) How to measure the thickness of plate correctly?
4) What causes underindication and overindication?
5) What can indicate that caliper is mishandled?
6) Describe the modification of caliper.
Lesson 4. SYSTEM DEFECTS
Exercise 1. Read and learn the following words and expressions.
Synonyms:
Vocabulary notes:
1. shoal/shallow water – мелководье
2. stroke – ход, такт
3. suction – всасывание
4. particle – частица, комок
5. micrometer – микрометр
6. hiss – посторонний шум, шипение
7. air pocket – воздушная пробка
8. indicator cock – индикаторный кран
9. fuel nozzle – форсунка
10. valve stem – шток клапана
11. discharge valve – выпускной клапан
12. jellyfish – медуза
13. air injection engine – компрессорный двигатель
14. pipe – труба
15. copper – медь
16. devastating – разрушительный
17. public system – коммунальная система водоснабжения
18. joint – место соединения
19. stopcock – кран
20. blowlamp – паяльная лампа
Exercise 2. Read, translate and discuss the text.
F uel system defects
Derangements in the fuel system are most likely to occur at the fuel measuring pumps. These pumps must handle a very small amount of oil at high pressure on each stroke and in order to do this the suction and discharge valves must be kept in perfect condition. A frequent source of trouble with these valves is dirt or grit in the oil. A small particle of sand or a thread qf waste under a valve will cause it to leak. Good strainers should be provided in the fuel oil supply line to the pumps and the strainers should be cleaned frequently. The pump plungers should be very carefully packed to prevent leakage of oil outward and air inward. Accumulation of air in the pumps will cause either irregular supply of fuel to the engine or stoppage. Stoppage of fuel supply to any one cylinder throws extra load on the other cylinders when the governor acts to increase the pumps discharge. Repeated regrinding of the pump suction valves will require careful checking of the pump timing.
Combustion defects
Normally the combustion in each power cylinder should be smokeless and complete and occur early in the stroke. Insufficient breaking up of the oil during injection will cause slow and incomplete burning and may be the result of clogged fuel nozzles, oil too cold or incorrect timing. Other causes of incomplete burning are compression too low, injection valves not correctly timed and air inlet pipes clogged.
Lubricating system defects
All Diesel engines today are lubricated by the forced feed method and no hand oiling of any part is required. This requires that the engine housings be closed in, to prevent loss of oil through splashing, and the oil piping, with the oil circulating pump, forms a closed circuit through which the same oil circulates repeatedly. Of course the most serious derangement in such a system is loss of pressure.
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Air system defects
The most serious derangement that can occur in the air system of an air injection engine, aside from the remote possibility of an explosion, is loss of injection air. Assuming that the compressor suction is open and the bleeder valve in the first stage properly adjusted, a falling off in the air pressure may be due to leaky, broken or stuck compressor valves, an injection valve sticking open, leaky air valve stem packing, leaky joints in the air piping or failure of the cooling water supply. If the air pressure falls to somewhere near the compression pressure in the power cylinders, unless the trouble can be located immediately, the engine should be stopped. If the engine is kept running, there will be a possibility of an explosion inside the injection valve body.
Exercise 3. Answer the following questions.
1) What derangements in the fuel system are most likely to occur?
2) What will cause the valve of the fuel measuring pump to leak?
3) When should combustion occur in each power cylinder?
4) What are the causes of incomplete burning?
5) When can complete stoppage of the cooling water supply occur?
6) What sea suctions do most well-designed ships have?
7) When is the high suction used?
8) Which sea suction is used in shallow water?
9) How are all Diesel engines lubricated today?
10) What is the most serious derangement that can occur in the air system of an air injection engine?
Exercise 4. Translate into English.
1. Неисправности топливной системы чаще всего встречаются в клапанах топливных насосов.
2. Скопление воздуха в насосах либо нарушит регулярную подачу топлива к двигателю, либо совсем прекратит ее.
3. Повторные притирки всасывающих клапанов требуют внимательной проверки.
4. Как правило, сгорание топлива в цилиндре должно быть полным, бездымным.
5. Неполное сгорание может происходить вследствие очень низкой компрессии.
6. Большинство судов, предназначенных для плавания на мелководье, имеют нижние и верхние приемные патрубки забортной воды.
7. При стоянке в тропической гавани приемный патрубок забортной воды может быть забит попаданием в него медузы.
Exercise 5. Make up a dialogue of your own based on the one given below.
A.: What are some of the causes of loss of injection air pressure?
В.: Leaky, broken or stuck compressor valves, injection air valve sticking open, leaky spray air valve stem packing, leaky joints in air piping, loss of cooling water.
A.: How can a start be had if there is no compressor available?
В.: Procure a bottle of CO2 gas and connect it to the starting air line. This gas is non-explosive and safe to use for this purpose.
A.: What are some of the causes of failure of an engine to start firing after it begins to turn on air?
В.: Fuel pumps not discharging oil, incorrect timing of fuel valves, low compression, injection air pressure too low and cylinders too cold.
A.: What are some of the causes of cracked cylinder heads?
В.: Unequal heating, due to poor design, air pockets in jacket, insufficient cooling water and overloading.
A.: How does wear on main bearings cause crank shaft to break?
В.: By throwing the shaft out of line and causing it to be bent in alternate directions twice in every revolution.
A.: Give the valve timing for the average and large 4-cycle engine.
В.: Injection valve opens 5 degrees before top center, injection valve closes 49 degrees past top center, exhaust valve opens 140 degrees past top center, air inlet valve opens 15 degrees before top center, exhaust valve closes 10 degrees past top center, and air inlet closes 214 degrees past top center. When in use, the air starting valve opens at top center and closes at 128 degrees past top center.
Burst of pipes
Burst of pipes in the water system is one of the most common plumbing problems both in the home and the public system. Several things can cause burst pipes, the main one is freezing conditions.
The most likely cause of a burst pipes will come from frozen temperatures and unprotected piping. A pipe bursts when frozen due to the expansion of the water as it becomes ice. This puts pressure on the pipe from the inside and something has to give. This almost always is the soft copper or plastic of the pipe. Sometimes these breaks can be at the weaker joints or in the middle of the pipe. As quite a lot of piping is hidden in flooring, roof spaces or walls, the damage caused can be devastating.
If a pipe freezes...
Remember: don't leave taps dripping or running as the water may not drain down the plughole if the pipe below is frozen.
If a pipe bursts...
Exercise 6. Answer the following questions.
1) What is the main cause of burst of pipes?
2) Explain why pipes burst when frozen.
3) What kind of material in pipes can’t stand the pressure?
4) Why is the damage so devastating?
5) What is necessary to do when pipes got frozen or burst?
6) What other advice can you give?
Starting difficulties.
Failure of the engine to start on air may be due to one or more of the following causes: starting air pressure too low, incorrect timing of starting air valves, one or more starting air valves stuck, compression relief gear out of order, stop valve in air line closed, or, if starting after working on the engine, the jacking gear may still be engaged.
Improperly refined oil.
Fuel oil must, during the refining process, be treated with sulphuric acid and this acid must later be neutralized with soda. If this neutralizing agent is not thoroughly washed out of the oil, its presence cannot be detected without chemical analysis nor is it removed by the filtering and straining methods ordinarily used on shipboard. When the engine is opened up after running on this insufficiently washed oil the entire surface of the combustion spaces in the cylinders will be found to have a coating of gritty material which looks and feels like sand but which is mostly sodium sulphate. It does not cause any immediate derangement of the engine but it does cause considerable wear of piston rings and cylinder liners. When such deposits are found the only remedy is to stop using the fuel from that particular refinery.
Cracked crank shafts.
During the early development period cracked crank shafts were so common that it was considered one of the inevitable hazards associated with Diesel engine operation. This trouble has become very rare, however, in modern practice.
Vibration.
The amount of vibration of an engine and of the ship's hull in which it is installed will depend on how well the reciprocating and rotating masses in the engine are balanced and the position of the engine relative to a nodal point in the hull. These are both matters over which the operating engineer has no control. Normally Diesel engines, especially in the large sizes, run with very little vibration but it sometimes happens that an engine will have a critical speed, a speed at which the twisting impulses imparted to the crank shaft by the pressure acting on the pistons coincide with the natural period of vibration of the crank shaft. When the engine operates at this speed violent vibration will occur that may result in loosening nuts, shaking off small fittings, breaking pipes and even breaking of the crank shaft, if continued long enough.
Exercise 3. Answer the following questions.
1) Due to what causes may the engine fail to start on air?
2) How can water get into fuel oil?
3) What is the only remedy against improperly refined oil?
4) What may a distinct loss in efficiency sometimes result from?
5) Why are cracked heads and cylinders not so common as they used to be in the early days of Diesel engineering?
6) What does the amount of vibration of an engine and of the ship's hull depend on?
7) Why was a cracked crank shaft considered one of the inevitable hazards associated with Diesel engine operation?
8) When may violent vibration occur?
Exercise 4. Translate into English.
1. Неисправности в двигателе, связанные с пневмозапуском, могут быть вызваны неправильной регулировкой воздушного пускового клапана и другими причинами.
2. Вода может попасть в топливо вследствие переменного использования цистерн для топлива и водяного балласта.
3. Резкое снижение температуры забортной воды влияет на мощность двигателя.
4. Трещины цилиндров происходят вследствие неравномерного нагрева, из-за конструктивных недостатков, плохой отливки, воздушных пробок.
5. Самой серьезной неисправностью, которая встречается в воздушной системе пневмозапуска, является падение давления воздуха, поступающего в цилиндр.
6. Бдительность со стороны механиков может исключить причины, вызывающие аварии двигателя.
7. На заре дизельных двигателей считалось, что трещины в цилиндрах – неотъемлемая часть эксплуатации данного типа двигателей.
8. При работе двигателя на максимальной скорости вибрации особенно опасны.
Exercise 5. Make up a dialogue of your own based on the one given below.
A.: What type of injection valve is used on modern engines?
В.: Modern engines use mechanical fuel injection and the valve is simply a spring loaded check valve with a nozzle on inner end containing one or more fine holes. When the pressure from the pump overcomes the tension of the spring the valve lifts and oil at high pressure is forced through the nozzle as a mist.
A.: What are some of the troubles experienced with injection valves?
В.: Leaks, due to grit or scale, burning of valve or seat, sticking of stem in its guide, bending of stem, leaky packing, clogging of atomizer plates and plugging of holes in flame plates or nozzles.
A.: How is a leaky injection valve repaired?
В.: Small leaks can be stopped by grinding the valve on its seat with very fine ground glass, carborundum, or prepared grinding compound, finishing up with polishing paste. If seat and valve are badly scored, the valve should be refinished by grinding in the lathe with a tool post grinder and the seat should be reamed, finished up by grinding.
A.: What precaution should be observed in cleaning injection valve stems?
В.: Cleaning should be done with kerosene, emery cloth should be used sparingly, or not at all, as it wears away the metal and increases the clearance between stem and guide. If this clearance becomes too great it offers an easy place for gummy oil and carbon to accumulate and the tendency of the stem to stick in the guide is increased.
A.: Why does the exhaust valve require more attention than the inlet valve?
В.: Because it is exposed to the action of the very hot gases that flow through it during the exhaust period. These gases may carry hard carbon, grit or scale which tend to cut the valve and seat and the heat tends to warp and burn the valve. The inlet valve passes no hot gas and is cooled by the inflowing clean air during each suction stroke.
Comprehensive reading. Read, translate into Russian and discuss the following text
Bedplates
Most bedplate troubles arise from surprising flexibility of what is usually a massive structure of cast iron. An example of this was the bed of a 500hp. engine that had been carefully reset to correct an original misalignment. After accurate alignment was complete and the bed was resting on permanent steel chocks, the spaces between chocks were closed with wooden filler pieces, as is a usual custom in marine work. It was found that a too thick filler piece driven under the bed at about its center with an ordinary hand hammer bowed up the bed enough to throw the coupling on the end of a crank shaft measurably out of line. This flexibility seldom results in any injury to the bed itself, but often has a serious effect on other parts of the engine structure, particularly the crank shaft.
Framing
Frames are subject to the same sort of deflection as the bed, and in many cases this deflection is caused by the bending of the bed.
Cylinders
Cylinders, or what may more precisely be termed cylinder jackets, give very little trouble, although on some of the of the older engines an occasional cracked cylinder will be found. Cylinder liners, however, are a prolific source of work for the repair yard. Liner casualities a occur either from wear or cracks. Wear is a normal result of engine use, but it sometimes assumes abnormal proportions if operating conditions are not right. Of course, the liner material has some bearing on rate of wear in service and there is some variation in the quality of liner iron found in different makes of engines, but there is not enough variation to make this an important factor in differences in length of liner life found in service. What appears to be the most important factor is the fuel used. Some fuel will contain more abrasive impurities than others, but it is believed that all fuel oil, even the highest commercial grades, should be passed through a centrifuge before being used in the engine.
Exercise 3. Answer the following questions.
1) What does the good condition of the engine depend upon?
2) What repairs can be done at sea?
3) Why are repairs at sea restricted to a certain amount of insignificant items?
4) What does the conscientious engineer take pride in?
5) What are the conditions under which maintaining the machinery becomes difficult?
7) What do most bedplate troubles arise from?
8) Why should all fuel oil be passed through a centrifuge?
9) Why are frames subject to the same sort of deflection as the bed?
10) What appears to be the most important factor in the length of a liner line?
11) How does the quality of liner iron influence the length of liner life?
Exercise 4. Translate the sentences from English into Russian
1. Fuel pumps should be examined and adjusted if necessary.
2. the condition of the cylinder bore is one of the main factors affecting the operation of a high speed oil engine.
3. Cylinder liners must be examined externally for deposits of scale.
4. The liner should be measured for wear and renewed, if the limit for wear has been reached.
5. The clearance of connecting-rod top and bottom ends should also be examined and adjusted.
6. At intervals of one year the maneuvering gear must be examined for wear at the joints of levers and rods.
7. Piston heads must be inspected for deposits of carbon in cooling spaces and cooling pipes.
8. Engine rooms and particularly the the floor areas between the underneath engine seatings and bilge areas, are frequently in need of coating maintenance.
9. All carbon deposits must be removed from cylinder ports.
10. When excessive lubricating oil consumption or excessive blow- by is observed the cylinder heads should be removed and the cylinder bores checked for wear.
Replacement parts
The most efficient and cost effective method of repair is the fitting of proper makers’ replacement parts in-situ by the ships’ engineers but this requires that the correct spare parts are always on the ship at the right time.
There are many thousands of different parts for the main and auxiliary diesels and hundreds more for each auxiliary machine. It soon becomes impossible to predict, even by computer, which part is going to be required next, so as to ensure its availability on board.
When an urgent request from a ship for spares is received, the problem of availability at makers’ works arises. Delivery times range from days to months. So delivery by air has become commonplace (usual).
When spares become available all that is necessary is an aircraft to deliver them. This may take only a few hours – always assuming the ship’s next destination is known.
Larger parts require special charter flights which take extra time to organize and the cost of transport can amount to many times the value of the part concerned.
Answer the following questions:
1 What is necessary to make repairs by replacement at the right time?
2 Why is it impossible to predict which spare part may be required next?
3 Why is the delivery of spares sometimes delayed?
4 What’s the most common way to deliver spares?
5 What information about the vessel should/must the makers’ works know to deliver the spares as soon as possible?
Watch the video “Shipyard repairs” and discuss the following topics.
[https://www.youtube.com/watch?v=FhzQ0sWOS4Y ]
1. Badplate troubles.
2. What are the main cause of cracked cylinder?
3. What does the good condition of the engine depend upon?
Head repairs
The head is usually the most complicated casting on the engine, and as such suffers most from heat troubles. The usual head repair is welding of cracks. Both oxyacetylene and electric welding are used, but the former is preferred if the location of the crack will permit its use. If the crack is near the outer edge of the head, where expansion and contraction stresses can be accommodated, gas welding can be used, but if the crack is near the center of the head or surrounded by unsymmetrical masses of metal, as is usually the case, electric welding must be resorted to. To make a successful head repair, electric welding must be done very skillfully and studding employed.
Crank shafts
Breakage of crank shafts in years gone by was accepted as one of the hazards inherent in Diesel-engine operation, but at the present time such breakage is very unusual. Most repair work on crank shafts consists of refinishing pins and bearings that have become scored or worn, or connecting alignment of the shaft in its bearings. Whenever it is necessary to renew a broken shaft, it is found that breakage is due to misalignment of torsional vibration. Wear of main bearings is more rapid in marine engines than in land engines. The more flexible nature of the structure on which the engine rests, as compared to the mass of concrete under the land engine, makes it more difficult to maintain a continuously unbroken oil film between shaft and bearing box.
Torsional vibration is sufficiently well understood that its occurrence can be predicted with accuracy in new engines and steps taken to eliminate it. It is a much less common sourse of trouble than in former years, but it is found occasionally.
Piston rods
Piston-rod troubles may be said to be non-existent in single-acting engines that have such rods, but in double-acting engines that have such rods, but in double-acting designs piston-rod breakage has been rather common.
Pistons
From the repairman’s point of view, the piston seems to be the most troublesome of all the major parts of the Diesel engine. The trouble encountered is usually cracking, or wear of ring slots. There are two ways in which cracking occurs: approximately radial cracks develop in the crown or circumferential cracks in the side or skirt. The first is the most common kind, and the appearance of the cracks indicates that is associated with the phenomenon of metal growth by repeated heating. The second type of fracture, cracks in the side, is almost invariably due to piston seizure in the liner and is usually associated with cooling-system failure. Welding procedure has been developed to the point where most cracked pistons can be salvaged at a cost substantially less than the price of a new one.
Valves and valve gear
Under this heading there is comparatively little to be recorded. The exhaust valve is the one most frequently in need of repair, due to the fact that a leak usually results in a burned-out valve ore seat.
Exercise 3. Answer the following questions.
1. What is the most complicated casting on the engine?
2. What is the usual head repair?
3. Why was breakage of crank shafts accepted as one of the hazards inherent in Diesel engine operation?
4. What does most repair work on crank shafts consist of?
5. Why is torsional vibration much less common source of trouble now than in former years?
6. What is crosshead trouble normally confined to?
7. In what engines may piston-rod troubles be said to be nonexistent?
8. From whose point of view does the piston seem to be the most troublesome of all the major parts of the Diesel engine?
9. What repair does the exhaust valve frequently require?
Cylinder Head Crack Repairs
The cylinder head, often referred to simply as the head, sits above the cylinders on top of the engine block. It closes the top of the cylinder which creates the combustion chamber. The gap between the head and the block is sealed by the head gasket. The head usually contains the passages that supply fuel and air to the cylinder and remove the exhaust.
Symptoms of a cracked cylinder head are identical to those of a blown head gasket and include engine misfires, leaking oil that drains from the engine and the seemingly unexplained presence of coolant fluid in engine oil. Cracks in a vehicle's cylinder head may be large enough to see or may be invisible to the naked eye, and diagnosis of this issue as opposed to issues with similar symptoms, such as a blown head gasket, requires specific techniques including the use of dye and pressure to expose the cracks. Because it can be easily confused with other issues, diagnosing a cracked cylinder head requires more than simple knowledge of symptoms.
Cracks in aluminum heads and blocks are relatively easy to repair by welding, but cast iron is much more difficult to weld. That is why pinning has long been the most popular method of repairing small cracks in cast iron blocks and heads. Pinning can repair about 80 percent of all cracks but it can't fix every kind of crack. A lot depends on the location of the crack and its severity. Tapered pins with sealer work well on most applications. Welding, on the other hand, restores integrity and allows you to fill cracks and holes. You can even change the shape of the combustion chamber or a port by adding metal.
Pinning is the most commonly used technique for repairing cracks in cast iron head, blocks and manifolds because it is fast, reliable and cheap. Pins can also be used to repair cracks in aluminum heads and blocks, too, although welding is often the preferred repair method for aluminum. Pinning is a relatively easy technique to learn and use, does not require much in the way of tools except a drill, guide fixture and tap, and uses no heat. Essentially, pinning involves drilling holes in a crack, installing overlapping pins to fill the crack, then peening over the pins to seal and blend the surface.
Exercise 6. Answer the following questions.
1. Where is cylinder head located?
2. What are the symptoms of the cracked cylinder?
3. Is it easy to find cracks? Why?
4. Describe the two methods of repairing cracks.
5. What is the best method to repair cracks? Explain your point of view.
Failure of diesel engine
The 2-stroke marine engine is the main propulsion power source and also the biggest machinery on a ship. A great amount of efforts, resources and time is spent to ensure that this massive engine runs smoothly and efficiently, taking the ship from one port to another without breakdowns.
But no matter how many precautions are taken, problems/breakdowns are bound to take place considering the complexity and number of parts the 2-stroke marine engine has.
1. Stuck Fuel Rack: This is one of the most common problem with oil fired 2 stroke marine engines. The governor controls the fuel pump delivery through a fuel rack, which is a combination of mechanical links. Sometimes the fuel rack gets stuck leading to lack of fuel supply in the concerned unit which results in either fluctuation in the engine RPM if running or engine will not start from standstill.
Solution: All the mechanical links of the fuel rack must be well lubricated and greased before starting the main engine. If after starting the main engine, the engine rpm is constantly fluctuating even at lower speed in calm weather, check all the fuel rack as one or more of them must be stuck.
2. Starting Air Valve Leakage: Any leakage from the starting air valve will lead to hot gasses going back to the engine air line, which may contain thin oil film. Such mixture of oil and film can lead to starting air line explosion. This kind of explosion is not very common now-a-days due to safety features incorporated in the air line. However, one cannot overlook the possibility of malfunctioning of such devices which can lead to explosion.
Solution: Normally, there is no remote monitoring of temperature for the air line supplying air to starting air valve. The best way to determine such fault is to check the temperature of the air line manually during maneuvering. This problem is more likely to occur when the engine is started frequently and not when engine is running continuously.
3. Fuel Leakage/ Fuel Valve Malfunction: Problem in the fuel system are also commonly observed in the main engine. When there is a deviation in temperature of one unit, the fuel system, especially the fuel valve needs to be checked. Overhauling and pressure testing of fuel valve must be done as per PMS. If the engine is maneuvered in diesel oil, there are chances of leakage from the pump seals. Also if the fuel treatment is improper and the fuel temperature is not maintained, it can lead to cracks and leakages in high pressure fuel pipe.
Solution: Any leakage in the main engine fuel oil system can be determined from the “high pressure leak off tank” level and alarm.
4. Sparks in the Main Engine Exhaust At Funnel: Marine engineers normally experience getting a call from bridge officer informing about sparks coming out from the funnel, which is the main engine exhaust. Sparks from funnel occur due to slow steaming and frequent maneuverings, which build unburnt soot deposits on the EGB boiler path.
Solution: Frequent cleaning (monthly) of the exhaust gas boiler to be preferred by the ship staff to avoid this problem.
5. Starting Air Leakage: This is also one of the most underrated yet common problems related to marine engines. The control air supplies air to different parts and systems of the main engine. It is always in open condition when the engine is in use. Small leakages are normal and can be rectified only by tightening or replacing the pipes or joints.
Solution: When the Engine room machinery is in working condition it is difficult to hear any air leakage sound. The best way is to trace all the air lines and feeling all the connections/ joints by hand for air leakage. The easiest way to find air leakages is when there is an intentional black out done for any job. At this moment all the machinery will be in “stop” position and leakage sound (a hissing noise) will be loud and clear. Note the leakage area to perform the repairs later.
6. Stuck Air Distributor: Air distributor is responsible for maintaining the air supply which opens the starting air valve in the engine cylinders. Since it’s a mechanical part, it is prone to malfunctioning, especially getting stuck. The main engine will not start if air distributor does not supply air to open the starting air valves as no air will be present in the cylinder to commence fuel combustion
Solution: Many engines such as MAN B&W have their air distributor located at the end, with inspection cover, which can be opened when the engine is not running for inspection and lubrication to avoid this problem.
7. Malfunctioning of Installed Gauges: It is very important to have local parameter gauges on various systems of the main engine. To note down the readings in the log book, it is always recommended to take the the local readings rather than remote readings. Often engineers find that one or two gauges (pyrometer, pressure gauges, manometers etc.) installed in the main engine are not working or in dilapidated condition. The reason for such condition can be due to loose parts and connections, and even vibrations.
Solution: Replace the faulty parameter gauges with new ones as early as possible.
8. Faulty Alarms and Sensors: The main engine is fitted with various sensors, which measure and transmit actual data to alarm console. Due to factors such as vibration, high temperature, humidity, dust etc. these sensors can malfunction leading to false alarms.
Solution: A routine checks needs to be performed on all engine room sensors and alarms. Different main engine safety alarms and trips also to be tried out at regular basis and faults to be attended immediately.
Exercise 6. Answer the following questions.
1. Describe all the possible problems with 2-stroke diesel engine.
2. Describe all the solutions to these problems.
3. What is the most common malfunction? How can you escape it?
TEST YOURSELF
TEST 1
1. What is a purpose of cylinder head safety valve?
a) A valve for safety stop (emergency) of the engine
b) For indication of engine being overloaded
c) To relieve high pressure in the cylinder to protect the engine from being damaged
d) To adjust the cylinder pressure to a safe working pressure.
2. The starting air valve is fitted for the purpose of:
a) Tuning the engine for staring preparations
b) To retard the engine revolution for maneuvering purpose
c) Bringing the engine up to full rpm to start the engine
d) Bringing the engine up to sufficient number of revolutions for combustion take place and engine to run.
3. When the temperature of lubricating oil is lowered, an increase will occur in:
a) Viscosity
b) Flash point
c) Pour point
d) Concentration of contaminants
4.During operation of the main engine, the heat absorbed by lubricating oil is removed by the:
a) Scavenge air cooler
b) Sump vents
c) Lube oil cooler
d) Any of the above
5. An excessive pressure drop across a lube oil strainer could indicate:
a) Any of the above
b) That the strainer is ok
c) That the strainer needs cleaning
d) That a relief valve is stuck open
6.Why is it important to keep the lub oil viscosity within safe limits?
a) To keep the oil protective film between moving metal surfaces
b) It is not important
c) To keep the additives in good condition
d) The lub oil has no influence on the oil’s lubrication ability
7.What could be the reason if the lub oil viscosity increases?
a) Heavy fuel oil leakage to the lub oil system
b) Water leakage to the lub oil system
c) The lub oil viscosity will not increase
d) High lub oil temperature
8.What could be the reason if the lub oil viscosity decreases?
a) Heavy fuel oil leakage to the lub oil system
b) Low lub iol temperature
c) Wrong lub oil pressure
d) Diesel oil leakage to the lub oil system
9.What are the compartments to be regularly checked with regard to water and oil leakages?
a) Tank top in the engine room
b) Bilge wells
c) Bilge tank(s)
d) All those listed in the other alternatives.
10.During standstill liquid may condense in the crankcase or oil separator. Why is it important to heat up the oil before start?
a) The compressor will run better
b) Compressor oil regulating system will operate better
c) To avoid the compressor oil to disappear from the crankcase during starting
d) It should never be done.
TEST 2
Answer "False" or "True".
Keys to test 1: 1-b; 2-d; 3-a; 4-c; 5-c; 6-a; 7-a; 8-d; 9-d; 10-c.
Keys to test 2: 1-true; 2-true;3-false;4-true;5-false;6-false;7-true;8-false;9-false;10-true;11-true;12-true.
ПРИЛОЖЕНИЕ
Synonyms
недостаток
default
defect
deficiency
disadvantage
drawback
fault
failure
fuisance
weakness
иметь цель, ставить целью
to aim
to be concerned
to be directed
to be intended
to comprise
частично устранить недостаток
to improve
to lessen
to mitigate
to overcome
to reduce
to relieve
устранить недостаток
to cure
to deal with
to do away with
to eliminate
to get rid of
to improve
to remedy
to overcome
to solve
to surmount
cпециалист
an engineer
a skilled person
a worker in this field
one acquainted with
one familiar with the art
one skilled in the art
cинонимы к слову «относиться»
to be concerned with
to deal with
to be directed to
to be related to
to be relevance to
to pertain
to refer to
to absorb / to take up поглощать
to acknowledge / to confirm / to affirm подтверждать
accumulation / pilling / assemblage накопление, аккумуляция
to be apt / to be possible быть возможным
to be attached / to be fitted быть присоединенным
avoidance / evasion избежание
being relieved / offgoing механик, которого сменяют
to bind / to grip заедать
to be engaged / involved in заниматься чем-либо
complicated / complex сложный
derangement / fault / malfunction неполадка.
design / construction конструкция
to develop / to evolve / to expand развивать, расширять
to discharge / to use up / to run down разряжать
disrepair/failure плохое состояние, неиспраность
distinct / definite / plain явный, определенный
donkey boiler / auxiliary boiler вспомогательный котел
to enter into force / to come into force / to take effect вступать в силу
to familiarize / to acquaint (with) ознакомиться
frequent / rapid частый, повторяющийся
garbage / waste / refuse мусор
to grease / to lubricate смазывать
ground / basis / cause основание
hazard / danger угроза, опасность
to immerse / to plunge / to submerge погружаться в воду
impart / relate / disclose сообщать, передавать
implementation / execution / performance осуществление, выполнение
to investigate / to consider / to examine рассматривать, расследовать
in the vicinity / nearby по близости, в районе
to lift / to heave / to raise поднимать
looseness / slackness неплотность (крепления)
to lubricate / to smear / to oil смазывать
moisture / humidity / dampness влажность
objective / aim / goal цель
to occur / to happen возникать, случаться
to plug up / to clog / to obstruct засорять(ся)
rapid / prompt / fast быстрый
rare / uncommon / scarce редкий
reasonable / acceptable / admissible приемлемый
to refine / to purify / to clarify очищать
relieving engineer / oncoming сменяющий механик
to reveal / to show показывать, раскрывать
to rotate/revolve вращаться
to run off / flow down / trickle down стекать
probability / likelihood вероятность
shoal / shallow water мелководье
thoroughly / fully / completely полностью
tightness / seal плотность, герметичность
to top up / to fill up / to add доливать
volume/ capacity / bulk емкость, вместимость
БИБЛИОГРАФИЧЕСКИЙ СПИСОК
1. Борецкий В.В. Методические указания к практическим занятиям по дисциплине «Английский язык» для студентов III -IV курсов специальности «Эксплуатация судовых энергетических установок» дневной формы обучения (часть II) / В.В. Борецкий, Ю.А. Мороз, В.А. Стеценко. – Севастополь: Изд-во СевНТУ, 2007 – 64 с.
2. Китаевич Б.Е. Морские грузовые операции: Учебное пособие по английскому языку / Б.Е. Китаевич, А.И. Короленко, М.Л Калиновская. – М.: Росконсульт, 1999. – 160 с.
3. Писарева Л.П. Английский язык. Сборник текстов и упражнений для старших курсов специальности «Эксплуатация судовых энергетических установок» очной и заочной форм обучения / Л.П. Писарева. – Петропавловск-Камчатский: КамчатГТУ, 2006. – 92с.
МЕТОДИЧЕСКОЕ ПОСОБИЕ
К практическим занятиям по дисциплине
«Английский язык» для студентов IV курса
специальности 0905
«Эксплуатация судовых энергетических установок»
дневной формы обучения
Севастополь 2017
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