UNIT III

UNIT III

BOILERS

Прочтите текст A и ответьте на следующие вопросы:

1. What kind of boilers are mostly used in ships today?

1. What valves are fitted to the water-tube boilers? Enumerate them.

TEXT A

BOILERS

Boilers are used on board the ship for producing steam. This steam may be used for driving the main engines, when steam tur­bines are fitted, or for driving auxiliary machinery such as the windlass. There are two basic types of boilers in use in ships: the fire-tube boiler, and the water-tube boiler.

The fire-tube boiler consists of a cylindrical steel shell, which contains a furnace at the bottom. Two or more furnaces may be fitted, depending on the size of the boiler. The furnace is connected to a combustion chamber, situated in the middle part of the boiler. The furnace, the combustion chamber and the tubes are all surrounded by water. Boilers are now mainly used for auxiliary purposes on board ship.

Water-tube boilers have replaced fire-tube boilers for generating steam for main engines. They have a steam drum at the top, which is partly filled with water, and water drums at a lower level. Banks of tubes, which also contain water, connect these drums. The furnace is located at the bottom and the whole system is con­tained in a fireproof casing. Down comer tubes are placed outside the gas system to act as feeders to the water drums.

Gases are heated in the furnace and pass upward through the banks, transferring their heat to the water in the tubes. Because the steam drum provides a reservoir of relatively cool water, con­vection currents are set up causing the water to circulate round the system. The bank of tubes offers a large surface area to the radiant heat of the furnace gases. This makes them very efficient. Super­heaters are added to the system to increase its efficiency. These are located between the rows of tubes.

Various valves and gauges are fitted to the boilers. For a wa­ter-tube boiler these include the following: safety valves, which are needed to release any excess steam, from the boiler; a main stop valve in order to control the passage of steam to the engines; feed valves to add water into the boiler; water level indicators to show the level of water in the boiler; thermometers and pressure gauges for showing the temperature and pressure inside the boiler. In or­der to be able to drain water from the system drain valves are fit­ted. Salinometer valves are also fitted to allow samples of water to be drawn off for testing. Chemical dosing valves are also necessary so that chemicals can be added directly into the boiler.

Е X Е R C I S Е S

I. Проверьте, знаете ли вы значения глаголов: to connect, to consist, to contain. Найдите их в тексте.

II. Найдите эквиваленты следующих выражений. Обратите внимание на соответствующие предлоги в английском языке.

Для приведения в действие (вспомогательных механизмов); (быть) в употреблении; состоять из (нескольких частей); в зависи­мости от (размера); соединяться с (топочной камерой); быть ок­руженным водой; быть заполненным водой; действовать в качест­ве питателя; размещаться вне (газовой системы); проходить через пучок труб; передавать тепло воде; добавлять прямо (не­посредственно) в котел; размещаться между рядами труб; на вер­шине (наверху); на дне; на нижнем уровне.

III. Найдите синонимы среди перечисленных слов.

Main; to be fitted; to be heeded; to indicate; to be able; to con­nect; to be installed; to be located; partially; to be necessary; basic; to show; to join; to be capable.

IV. Задайте вопросы к тексту согласно модели.

Model: What is .. ./the function/of…?

V. Переведите следующие предложения, обращая внимание на употребление инфинитива в функции обстоятельства цели (см. §§ 4—7 (Приложений).

1. В котел дополнительно введены (добавлены) перегреватели, чтобы увеличить его КПД (эффективность).

2. Предохранительные клапаны нужны (для того), чтобы вы­пускать из котла избыток пара.

3. Главный стопорный (запорный) клапан необходим, чтобы управлять прохождением пара к машинам.

4. Питательные клапаны установлены, чтобы добавлять воду в котел.

5. Указатель уровня воды используется (установлен), чтобы показывать уровень воды в котле.

6. Термометры я манометры установлены, чтобы показывать температуру и давление внутри котла.

3. Для того, чтобы выпускать воду из системы, установлены спускные клапаны.

8. Для того, чтобы брать пробы воды, устанавливается солемер.

9. Клапаны дозировки химикатов нужны, чтобы можно было добавлять химикаты прямо в котел.

VI. Опишите конструкцию и работу: a) fire-tube boilers; b) wa­ter-tube boilers (fig. 1).

VII. Переведите следующие предложения на русский язык, об­ращая внимание на функции "ing" forms (см. § 9 Приложений).

1. Boilers are used on board the ship for producing steam.

2. The steam may be used for driving the main engines, when steam turbines are fitted and for driving auxiliary machinery such as windlass.

3. Water-tube boilers have replaced fire-tube boilers for generat­ing steam for main engines.

4. Two or more furnaces may be fitted, depending on the size of the boiler.

5. Because the steam drum provides a reservoir of relatively cool water, convection currents are set up causing the water to circulate, round the system.

Fig.1 a) fire-tube boilers; b) wa­ter-tube boilers

CAUSE, DEPEND, RESULT

Запомните:

to cause — вызывать, заставлять

to be caused by… - вызываться чем-либо

to depend (оn) —зависеть (от)

to result in — приводить к...

to result from — про­исходить в результате чего-либо

VIII. Ответьте на вопросы по моделям.

А. Используйте: certainly, of course, no doubt.

Model 1: — Is the efficiency of the boiler connected with steam conditions?

— Certainly, it depends on steam conditions.

1. Is the amount of heating surface connected with the number of generating fire-tubes?

2. Is the time required to raise steam connected with composition of scale?

3. Is the method used for boiler cleaning connected with the composition of scale?

4. Is the amount of fuel burned per hour in the furnace connec­ted with the furnace volume?

5. Is the life of the brickwork connected with the maintenance of the unit?

6. Is the severances (зд. степень) of the brickwork trouble con­nected with the quality of fuel oil?

В. Используйте: I think, I believe в слова в скобках.

Model 2: —What is the cause of erosion? (the use of wet, steam)

— I believe, erosion is caused by the use of wet steam.

1. What is the cause of wastage (зд. утечка)? (leaking of man­hole joints).

2. What is the cause of distortion (деформация) of the chamber crown? (accumulation of mud and scale).

3. What is the cause of grooving (образование канавок)? (we­akness of the material).

4. What is the cause of circulation? (the difference, in specific weight of water steam and height of tubes)

5. What is the cause of overheating? (accumulation of scale)

6. What is the cause of fires in the bundle of tubes? (poor com­bustion)