- •Vocabulary
- •1. Give English equivalents.
- •2. Ask questions according to the models.
- •3. Supply prepositions.
- •4. Complete the sentences. Choose the right word from the list. There are more words than necessary!
- •5. Answer the questions.
- •6. Translate into English.
- •7. Write a dictation.
- •Vocabulary
- •1. Choose the proper verb form.
- •2. Answer the questions.
- •Vocabulary
- •1. Give English equivalents:
- •2. Complete the sentences:
- •3. Give English equivalents to the words in brackets:
- •4. Self-assessment questions:
- •5. Translate into English:
- •1. Translate the word combinations into Russian and use them in your own sentences.
- •2. Choose the proper verb form, active or passive.
- •Vocabulary
- •1. Translate into English.
- •2. Supply the proper preposition.
- •Vocabulary
- •Give English equivalents:
- •Answer the questions according to the models:
- •Match the type of the boiler with its principle of classification:
- •Self-assessment questions:
- •5. Translate into English:
- •Vocabulary
- •1. Give answers to the questions:
- •2. Translate into English:
- •Vocabulary
- •1. Give English equivalents:
- •2. Ask questions according to the model:
- •3. Complete the sentences:
- •4. Answer the questions:
- •5. Translate into English.
- •Vocabulary
- •1. Give English equivalents:
- •2. Change these sentences using the modal verbs may, can, must:
- •3. Change these sentences into the passive:
- •4. Supply prepositions:
- •5. Answer the questions:
- •6. Translate into English:
- •Vocabulary
- •1. Give English equivalents:
- •2. Supply prepositions:
- •3. Self-assessment questions:
- •4. Translate the words into Russian.
- •5. Choose the proper verb and put it into the correct form. There are more verbs than necessary.
- •6. Translate into English:
- •Unit VI. The superheater
- •Vocabulary
- •1. Give English equivalents:
- •3. Answer the questions:
- •Unit VII. The economizer
- •Vocabulary
- •1. Give English equivalents:
- •2. Ask questions according to the model in the singular or in the plural:
- •3. Insert prepositions and conjunctions:
- •4. Answer the questions:
- •5. Translate the phrases containing comparatives and superlatives:
- •6. Translate into English:
- •How to operate a boiler? Boiler Starting Procedure - Checks and Techniques
4. Answer the questions:
1. What characteristics should be known to determine the quality of fuel?
2. What is oil composed of?
What does the grade of oil depend on?
What is the calorific value?
How do we measure the heat value of fuel oil?
Is viscosity essential for fuel practicability?
Does the temperature affect the flow?
What is the specific gravity?
What is the difference between the flash point and the ignition temperature?
Why is it necessary to know the pour point?
What other characteristics should we know?
5. Translate into English.
Качество топлива определяется его элементарным составом, теплотой сгорания, вязкостью, удельным весом, температурой вспышки, температурой воспламенения и застывания, а также некоторыми другими характеристиками.
Топливо состоит из следующих химических элементов – углерода, водорода, кислорода, азота и частично серы.
Теплота сгорания топлива – это тепловая энергия, высвобождаемая во время сгорания.
Различают две теплоты сгорания: высшую и низшую.
Вязкость – это сопротивление при течении жидкости.
Вязкость определяют с помощью вискозиметров.
Тяжелое топливо обычно характеризуется высокой вязкостью.
Удельный вес - это соотношение веса определенных равных объемов топлива и воды.
При температуре воспламенения топливо начинает гореть.
Температура застывания – это самая низкая температура, при которой топливо можно перекачивать.
Следует также принимать во внимание следующие характеристики топлива: содержание золы, серы, влаги, содержание механических примесей, общую кислотность и некоторые другие характеристики.
TEXT B
Fuel oils characteristics
Fuel oils have various characteristics which determine their performance and are quoted in specifications.
The specific gravity 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.
Viscosity is a resistance to flow. A highly viscous fuel will therefore require heating in order to make it flow. Measurement of viscosity is by Redwood, Saybolt seconds for a given volume of fuel.
The ignition quality of a fuel is measured by the time delay between injection and combustion, which should be short for good controlled burning.
The flash point is the temperature at which the fuel is ignited with a small open flame.
The pour point is slightly above the temperature at which the fuel just flows under its own weight. It is the lowest temperature at which the fuel can be easily handled.
Sulphur content is of importance since it is considered a cause of engine wear. A maximum limitis usually included in specifications.
The calorific value of a fuel is the heat energy released during combustion. Two values are used, the more common being the Higher Calorific Value, which is the heat energy resulting from combustion. The Lower Calorific Value is a measure of the heat energy available and does not include the heat energy contained in steam produced during combustion but passing away as exhaust. The measurement is obtained from a calorimeter test where a small fuel quantity is burnt under controlled conditions.
E X E R C I S E S
1. hydrometer; calorific value; pour point; flash point; heavy; specific gravity
The specific gravity is obtained by means of a …
… is the lowest temperature at which the fuel can be easily handled.
… oils usually have high viscosity.
Deposits; viscosity; calorimeter; hydrometer; fuel; automatically; steam.
In Europe to measure … they use either Redwood or Saybolt seconds.
The practical method of determining the B.t.u. equivalent of oil fuel is by means of a … .
2. … is a relation between the weights of a definite volume of oil and water.
TEXT C
Пивненко стрю47 -9
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 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 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.