Прочитайте и переведите текст.

Any internal combustion engine has a four-stroke cycle or a two- stroke cycle.

The four-stroke cycle consists of:

1. the suction stroke

The piston starts downward; the air inlet valve is open and air is drawn into the cylinder; the exhaust valve and the fuel valve are closed.

2. the compression stroke

The air inlet valve closes; the piston rises; the air is compressed; the temperature rises.

3. the combustion expansion stroke

The fuel injection valve opens and the fuel oil is sprayed into the cylinder under the high pressure; the high temperature of the compressed air in the cylinder ignites the fuel; the piston starts down with the gas expanding.

4. the exhaust stroke

The exhaust valve opens and the burned gases flow out of the cylinder through the exhaust pipe. Then the exhaust valve closes, the air inlet valve opens and the cycle of operation starts again.

In the two-cycle diesel engine there is a ring of exhaust ports around the bottom of the cylinder and scavenging ports in place of air inlet valves. The complete cycle of operation takes place in two-strokes of the piston.

Lesson 3

Boilers Types of Boilers

Слова и словосочетания к тексту:

fire-tube boiler	—	огнетрубный котел
water-tube boiler	—	водотрубный котел
straight-tube water boiler	—	водотрубный судовой котел с прямыми трубами
bend-tube water boiler	—	водотрубный судовой котел с изогнутыми трубами
coil-tube water boiler	—	водотрубный судовой котел со змеевидными трубками
cross-drum boiler	—	котел с поперечным расположением коллекторов
longitudinal-drum boiler	—	котел с продольным расположением коллекторов

Прочитайте и переведите текст.

There are two types of boilers: fire-tube boilers and water tube boilers. A fire-tube boiler is a boiler in which water is outside the tube and hot gases pass through the tube.

In water-tube boilers water circulates through the boiler tubes. At present water-tube boilers are preferably used because they are lighter in weight and permit to use high pressures and temperatures combined with increased efficiency and safety in case of damage. Water-tube boilers can be classified according to the arrangement of water tubes into straight-tube, bent-tube or coil-tube types. According to the arrangement of the drums they can be classified into cross-drum boilers and longitudinal- drum boilers.

Упражнение 1. Ответьте на следующие вопросы.

1. What types of boilers do you know?

2. What are the fire-tube boilers?

3. What are the water-tube boilers?

4. What are the advantages of water-tube boilers?

General Information on Heat Transfer

Слова и словосочетания к тексту:

difference n	—	разница
heat exchange	—	теплообмен
heat transfer	—	теплопередача
conduction n	—	проводимость
convection n	—	конвекция
heating surface	—	поверхность нагрева
liquid n	—	жидкость
motion v	—	движение
particle n	—	частица
thermal radiation	—	тепловое излучение
vapour n	—	пар, водяные пары
specific heat	—	удельная теплота
glowing surface	—	поверхность накаливания
flue gases	—	топочные газы