Unit 1

TEXT A

MARINE BOILERS

A boiler in one form or another is found on every type of a ship. Where the main machinery is steam powered, one or more large water-tube boilers are fitted to produce steam at very high temperatures and pressures. On a diesel-powered vessel, a smaller boiler is fitted to provide steam for the various ship’s needs.

A boiler is used to heat feed water in order to produce steam. The energy released by burning fuel in the boiler furnace is stored (as temperature and pressure) in the steam. All boilers have a furnace or combustion chamber where fuel is burnt to release its energy. Air is supplied to the boiler furnace to enable combustion of the fuel to take place. A large area between the combustion chamber and the water enables the energy of combustion, in the form of heat, to be transferred to the water.

A drum is provided where steam and water can separate. In the steam generation process the feed water enters the boiler where it is heated and becomes steam. The feed water circulates from the steam drum to the water drum and is heated in the process. Some of the feed water passes through tubes surrounding the furnace, i.e. water-wall and floor tubes, where it is heated and returned to the steam drum.

Large-bore downcomer tubes are used to circulate feed water between the drums. The downcomer tubes pass outside of the furnace and join the steam and water drums. The steam is produced in the steam drum and may be drawn off for use from here. It is known as ‘wet’ or saturated steam because it contains small quantities of water. The steam may also pass to a superheater which is located within the boiler. Here steam is heated and ‘dried’ and water is converted into steam.

The hot gases produced in the furnace are used to heat the feed water and to generate steam. The gases pass over an economiser through which the feed water passes before it enters the boiler. The exhaust gases may also pass over an air heater that warms the air for combustion before it enters the furnace. In this way, a large proportion of the heat energy from the hot gases is used before they are exhausted from the funnel.

Vocabulary

marine boiler судовойкотел

main machinery главнаяЭУ; гребнаяустановка

steam powered паросиловой

water-tube boiler водотрубныйкотел

produce, v производить, выпускать; вырабатывать

fit, v устанавливать; монтировать; оснащать

provide, v снабжать; устанавливать; обеспечивать

heat, n, v тепло; греть, нагревать

feedwater питательная вода

inorderto для того, чтобы

release, v выделять; выпускать

furnace, n топка

store, v накапливать; хранить

enable, v делать возможным

takeplace происходить

drum, n барабан

water-walltubes боковые экранные трубы (трубки)

floortubes донные трубы (трубки)

large-bore с большим (внутренним) диаметром

downcomertubes нисходящие трубки

pass, v проходить

join, v соединять

draw (drew; drawn) off, v отводить; выводить

saturatedsteam насыщенный пар

superheater, n пароперегреватель

economizer, n экономайзер

airheater воздухоподогреватель

funnel, n дымовая труба

EXERCISES

1. Give English equivalents.

Котел; в той или иной форме; вырабатывать пар; дизельное судно, теплоход;

различные судовые нужды; топка котла; давление; камера сгорания, топка, топочная камера; подавать; горение; происходить; в виде; процесс выработки пара; поступать в котел; превращаться в пар; циркулировать; паровой барабан; водяной барабан; проходить по трубам; снаружи; отработавшие, выхлопные газы; таким образом; тепловая энергия.

2. Ask questions according to the models.

Model A. The heat is generated in the furnace. Where is the heat generated?

1. The steam is produced in a steam boiler.

2. Temperature and pressure are stored in the steam.

3. Air is supplied to the boiler furnace.

4. The superheater is located within the boiler.

5. The hot gases are produced in the furnace.

Model B. The tubes surround the furnace. What do the tubes surround?

1. A steam boiler produces steam from feed water.

2. Air enables combustion of the fuel.

3. Downcomer tubes join the steam and water drums.

4. Hot gases produce steam.

5. The feed water enters the boiler.

3. Supply prepositions.

1. Steam is produced … very high temperatures and pressures.

2. Fuel is burnt … the furnace.

3. The feed water circulates … the steam drum … the water drum.

4. There is a large area … the combustion chamber and the water … the boiler.

5. The energy of combustion is transferred … the water.

6. Hot gases are exhausted … the funnel.

4. Complete the sentences. Choose the right word from the list. There are more words than necessary!

Furnace, funnel, superheater, drum, tube, economizer, air heater

1. A part of the steam boiler that burns fuel is … .

2. A device of the boiler that heats the feed water is the … .

3. A device of the steam boiler that warms the steam is the … .

4. A device of the boiler that heats air for combustion is the … .

5. A device of the boiler that provides separation of steam and water is the … .