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Архитектура Аудит Военная наука Иностранные языки Медицина Металлургия Метрология Образование Политология Производство Психология Стандартизация Технологии |
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Архитектура Аудит Военная наука Иностранные языки Медицина Металлургия Метрология Образование Политология Производство Психология Стандартизация Технологии |
Choose the proper word or word combination from the list. There are more words than necessary. Translate the sentences into Russian.
Hydrometer; the ignition quality; the flash point; calorific value; pour point; heavy; specific gravity; the Lower Calorific Value; viscosity 1. … is the lowest temperature at which the fuel can be easily handled. 2. … oils usually have high viscosity. 3. … is a relation between the weights of a definite volume of oil and water. 4. In Europe to measure … they use either Redwood or Saybolt seconds. 5. … is the heat energy available and does not include the heat energy passing away as exhaust. 6. … of a fuel is measured by the time delay between injection and combustion, which should be short for good controlled burning. 7. … is the temperature at which the fuel is ignited with a small open flame.
Translate the word combinations and use them in your own sentences. to determine performance to quote in specifications to compare to the weight of water to express as a ratio to measure the ignition quality of fuel to handle fuel to release during combustion to pass away as exhaust to obtain measurement
TEXT C FUEL OIL SYSTEM
A furnace provides steady burning of fuel. When burning fuel the following characteristics of it should be taken into consideration: viscosity, specific gravity, flash point, pour point, heating value and some others. A furnace fuel oil system consists of a fuel tank from which fuel is drawn through a strainer by a pump. This pump delivers fuel under pressure through a filter and a heater to the burners. In the burners it mixes with air and is ignited inside the furnace. The complete furnace fuel oil system consists of: 1. Oil fuel filling system – to replenish the fuel tanks. 2. Suction system – to allow any tank to be used and for transferring fuel from remote tanks. 3. Discharge system – to deliver fuel under pressure to the burners. Fuel is burnt in the furnace in suspension. Therefore, a burner used for atomization is a very important element in fuel burning equipment. Although there are a lot of types of burners they work on the same principle. The fuel is heated to the burning temperature, which reduces viscosity and then delivered under pressure to the burner body. The fuel passes through the holes which give it a rotary motion and then through the orifice in a conical spray – to the furnace. Vocabulary
provide, v обеспечивать steady, adj устойчивый, постоянный strainer, n сетчатый фильтр; приемная сетка burner, n горелка ignite, n зажигать; воспламенять; запаливать fuel oil filling system система приема топлива replenish, v пополнять transfer, v передавать suspension, n суспензия; взвесь therefore, adv поэтому although, adv несмотря на то, что burner body корпус горелки orifice, n отверстие: сопло
E x e r c I s e s Supply prepositions. 1. Fuel oil characteristics should be taken … consideration when burning fuel. 2. A furnace fuel oil system consists … a fuel tank from which fuel is drawn … a strainer … a pump. 3. Fuel is ignited … the furnace. 4. Fuel is delivered … pressure … the burners. 5. Suction system is used … transferring fuel … remote tanks. 6. The fuel passes … the holes and then through the orifice … a conical spray … the furnace. Answer the questions. 1. What does a furnace provide? 2. What fuel oil characteristics should be taken into consideration when burning fuel? 3. Where is fuel drawn from? 4. Where does fuel mix with air? 5. What does the complete furnace fuel oil system consist of? 6. What is oil fuel filling system used for? 7. What system is used to deliver fuel under pressure to the burners? 8. What is the principle of burner operation?
UNIT 5
TEXT A FEED WATER
Feed water is the water supplied to a boiler to generate steam or hot water. It is delivered to the boiler by the feed pump. As the water is evaporated, the impurities in it remain in the boiler in the form of the salt deposits. Water containing impurities may lead to the following problems in boilers: scale, foaming, priming and corrosion. The chief salts forming scale are those of calcium and magnesium. Magnesium sulphate is a salt commonly found in boiler water and it forms a soft, sludgy mass, not very harmful, which can be removed by blowing down. Calcium sulphate produces a hard brittle scale. Alkalis or phosphate are sometimes put into marine boilers to prevent scale. Foaming may be the result of dirty water, certain types of organic matter, oils in solution, the presence of excess alkalinity. Oil is very injurious to a boiler: it adheres to the tube surfaces and causes overheating and rupture of tubes. Priming may be due to improper construction of boiler or extremely high ratings. The most common measure to prevent foaming and priming is to maintain the water at the lowest level. Avoiding high water levels, excessive boiler loads, and sudden load changes also helps. If foaming and priming occur, the blow off is opened several times, and fresh water is added. The main cause of boiler corrosion results from the dissolved gases, oxygen and carbon dioxide, found in feed water. They will react with the metals in the boiler system and lead to boiler corrosion. In order to protect the boiler from these contaminants, they should be controlled or removed, usually by use of a deaerator. Acids due to oils in solution may be neutralized by the addition of sodium carbonate. For efficient boiler operation a chemical analysis of the feed water must be run at least once a day.
Vocabulary
feed water питательная вода evaporate, v испаряться impurity, n примесь; загрязнение remain, v оставаться salt deposits отложения солей scale накипь foaming вспенивание priming вскипание soft sludge мягкий шлак; шлам brittle scale хрупкая, ломкая накипь harmful, adj вредный blowing down нижнее продувание alkali, n щелочь organic matter органическое вещество solution, n раствор excess alkalinity избыточная щелочность injurious, adj вредный adhere, v прилипать; приставать rupture, n разрыв rating, n мощность load, n нагрузка blow off верхнее продувание fresh water свежая; пресная вода dissolve, v растворять contaminant, n загрязняющее вещество; примесь deaerator, n деаэратор acid, n кислота sodium chloride хлорид натрия
E X E R C I S E S 1. Give English equivalents:
Питательная вода; подавать; питательный насос; содержать примеси; приводить к проблемам; коррозия; образовывать; кальций; магний; сульфат магния; мягкая масса; предотвращать образование накипи; наличие; вызывать перегрев; мера; избегать; чрезмерные нагрузки; углекислый газ; карбонат натрия, проводить химический анализ.
2.Change these sentences using the modal verbs may, can, must:
1. Foaming is due to the presence of dirty water in the boiler. 2. Oil in the feed water is very injurious to the boiler. 3. Priming is also due to a poorly designed steam drum. 4. Acids are neutralized by the addition of sodium carbonate. 5. A little of the chemicals is added at a time. 3. Change these sentences into the passive:
1. The addition of alkalis prevents scale formation. 2. The presence of oils in solution causes foaming. 3. Some of the salts produce a soft sludge. 4. The chlorides of sodium and magnesium and the sulphate of iron cause corrosion. 5. We may neutralize acids by the addition of sodium carbonate.
4. Supply prepositions: 1. Feed water is the water supplied … a boiler … the feed pump. 2. The impurities … the boiler remain … the form of the salt deposits. 3. Alkalis or phosphate are put … marine boilers to prevent scale. 4. Oil is very injurious … a boiler as it adheres … the tube surfaces. 5. Priming may be due … improper construction of boiler. 6. To prevent priming it is necessary to maintain the water … the lowest level. 7. Corrosion results … the dissolved gases found … feed water. 8. Acids may be neutralized … the addition of sodium carbonate. 5. Answer the questions: 1. What is feed water? 2. By what device is the feed water supplied to the boiler? 3. What substances remain in the boiler as the water is evaporated? 4. What problems may water containing impurities lead to? 5. How can a soft sludge be removed? 6. What salt produces a hard scale? 7. What may foaming be the result of? 8. What may priming be due to? 9. What gases cause corrosion? 10. How often must a chemical analysis of the feed water be run? 6. Translate into English: 1. Питательная вода подается в котел насосом. 2. Примеси воды остаются в котле в виде отложений. 3. Мягкий шлак может быть удален из котла продуванием. 4. Некоторые соли образуют твердую накипь. 5. Для предотвращения накипи в котле используются щелочи и фосфаты. 6. Содержание в воде органических веществ может привести к вспениванию. 7. В случае вскипания применяется продувание и добавляется свежая вода. 8. Растворенные в питательной воде кислород и углекислота вызывают коррозию стенок котлов. 9. Химический анализ питательной воды должен производиться на судне не реже одного раза в день.
TEXT B Purity of boiler feed water
Modern boilers require very pure feed water. The water required for boiler feed purposes, i.e. for steam generation should be of very high quality and thus requires a lot of treatment. Untreated water, containing impurities may lead to the following problems in boilers. Most pure water will contain some dissolved salts. These salts then adhere to the heating surfaces as a scale and reduce heat transfer, which can result in local overheating and failure of the tubes. Other salts remain in solution and may produce acids which will attack the metal of the boiler. An excess of alkaline salts in a boiler will cause cracking of the metal which may lead to serious failure. The presence of dissolved oxygen and carbon dioxide in boiler feed water can cause considerable corrosion of the boiler and feed systems. When boiler water is contaminated by suspended matter, an excess of salts or oil, foaming may occur. This is foam which collects on the water surface in the boiler drum. Foaming leads to priming which is the carry-over of water with the steam leaving the boiler drum. Any water present in the steam entering a turbine will do considerable damage. Various amounts of different metal salts can be found in water. These include the chlorides, sulphates and carbonates of calcium, magnesium. These dissolved salts in water make up the 'hardness' of the water. Calcium and magnesium salts are the main causes of hardness.
E X E R C I S E S 1. Find the corresponding Russian translation. Memorize the phrases.
Complete the sentences. 1. Boiler feed water is required for …. 2. Untreated water leads to …. 3. Dissolved salts may lead to such problems as …. 4. An excess of alkaline salts in a boiler causes …. 5. Foaming occurs when …. 6. Such metal salts as … make up the 'hardness' of the water.
TEXT C CONTAMINATION OF FEED water
The quality of boiler water plays an important role in boiler operation. Contamination of boiler water leads to several types of problems, including the main ones – corrosion and scale formation. Inside the boiler system, the boiler feed water passes through a series of tubes and equipment. The feed water is always chemically treated to reduce the effects of harmful minerals and gases. The main problem starts when a lot of this boiler feed water is lost through leakages and processes such as boiler blow down, soot blowing etc., and make-up water is added to compensate this loss. This make-up water brings in a lot of the impurities into the boiler system. How is the make-up feed water contaminated? Boiler feed water is mainly taken from the fresh water generator. The sea water contains a large amount of salts and other dissolved minerals and gases. Many of them are harmful and eventually lead to boiler problems. Saltdeposits act as insulators and lower the heat transfer rate. The insulating effect of deposits also causes the boiler metal temperature to rise and lead to tube-failure by overheating. Large amounts of such deposits throughout the boiler can reduce the heat transfer and decrease the overall boiler efficiency.
Vocabulary contamination, v загрязнение treat feed water подготавливать питательную воду harmful, adj вредный, опасный leakage, n утечка, течь boiler blow down продувание котла sootblowing сажеобдувание fresh water generator опреснитель; опреснительная установка dissolve, v растворять salt deposits отложение солей insulator, n изолятор heat transfer rate скорость теплоотдачи overall, adj общий
E X E R C I S E S 1. Change these sentences using the modal verbs may, can, must:
1. Foaming is due to the presence of dirty water in the boiler. 2. Oil in the feed water is very injurious to the boiler. 3. Priming is also due to a poorly designed steam drum. 4. Acids are neutralized by the addition of sodium carbonate. 5. A little of the chemicals is added at a time. 2. Change these sentences into the passive:
1. The addition of alkalis prevents scale formation. 2. The presence of oils in solution causes foaming. 3. Some of the salts produce a soft sludge. 4. The chlorides of sodium and magnesium and the sulphate of iron cause corrosion. 5. We may neutralize acids by the addition of sodium carbonate.
UNIT 6
TEXT A BOILER PARTS. THE FURNACE
A furnace provides steady burning of fuel. The furnaces of marine water-tube boilers are lined with refractory firebrick backed up by the insulating bricks. This brickwork acts as furnace insulation and also, by maintaining a high furnace wall temperature, assists combustion. Water walls are used in water-tube boilers to contain the heat of the furnace and reduce the amount of refractory material required. Water walls consist of a number of tubes and extend along the sides of the furnace setting. To provide the efficient combustion process of burning oil fuel, a certain set of conditions is necessary: maintenance of high furnace temperature, provision of continuous oil fuel and air supply and removing products of combustion. The oil is first heated in steam or electric fuel oil heaters. This reduces its viscosity and makes it easier to pump, filter, and finally to atomize. The heated oil passes through the burners where it is atomized; this process breaks it up into a fine spray of droplets presenting a very large surface area of oil to the combustion processes. Different types of burners have been designed for burning liquid fuel. Mechanical oil burners and steam-assisted ones are employed to obtain efficient atomization. Mechanical atomizing oil burners may be classified according to their method of atomization as centrifugal atomizers and rotary cup atomizers. Steam-assisted oil burners are widely spread in marine practice. Their advantages are high quality atomization and a wide range of fuel oil feed control.
Vocabulary steady, adj устойчивый firebrick, n огнеупорный кирпич brickwork, n кирпичная кладка insulation, n изоляция assist, v помогать; способствовать water wall экран из водогрейных трубок amount, n количество setting, n кладка; обмуровка set of conditions комплекс условий maintenance, n поддержание atomize, v распылять; тонко измельчать to break up разбивать(ся) droplet, n капля surface, n поверхность mechanical oil burner механическая форсунка steam-assisted oil burner паромеханическая форсунка centrifugal atomizer центробежный распылитель rotary cup atomizer форсунка с вращающимся распылителем range, n диапазон oil feed подача топлива
E X E R C I S E S
Give English equivalents. Обеспечивать; горение топлива; облицовывать (футеровать); выступать в качестве; горение; тянуться; поддерживать; высокая топочная температура; непрерывная подача; продукты сгорания; топливоподогреватель; уменьшать вязкость; проходить; мелкораспыленная струя; по методу распыления; преимущество; регулирование.
Supply prepositions. 1. Water-tube boilers are lined … refractory firebrick. 2. The brickwork acts … furnace insulation. 3. Water walls consist … a number of tubes and extend … the sides of the furnace setting. 4. The oil is first heated … steam or electric fuel oil heaters. 5. The heated oil passes … the burners where it is atomized. 6. Mechanical atomizing oil burners may be classified … … their method of atomization. 7. Steam-assisted oil burners are widely spread … marine practice. 3.Self-assessment questions. 1. What does a furnace provide? 2. What are furnace walls lined with? 3. What is the function of water walls? 4. What set of conditions is necessary to provide the efficient burning of oil fuel? 5. Why should the oil be heated? 6. What types of burners do you know? 7. What are the advantages of steam-assisted oil burners? Популярное:
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