After text activity. Exercise 1.Read and memorize using a dictionary:

I. Reading Exercises:

Exercise 1. Read and memorize using a dictionary:

Facility, match, oversized, fuel bill, excessive, undersized, cope adequately, to be on the safe side, water treatment requirements, descriptive, brass, flue gases; burner; three-pass boiler;stack outlet; rear; encase; steam drum; mud drum;upper drum; heat application; commonality  

Exercise 2. Answer the questions:

1) What does a heating system consist of?

2) How are boilers classified?

3) How are steel boilers generally divided?

4) What are the advantages of a fire-tube boiler?

5) What are the advantages of a water-tube boiler?

Exercise 3. Match the left part with the right:

1 If the boiler is oversized,	a) it may not generate enough heat in winter.
2. If the boiler is undersized,	b) "high-pressure" or "low-pressure" and "steam boiler" or "hot water boiler.
3. Boilers are classified as	c) the exact opposite of a fire-tube.
4. A water-tube design is	d) the fuel bills will be excessive.

Exercise 4. Open brackets choosing the right words:

The boiler does not directly (govern/ control) the amount of radiators fitted to the system. It is the powerof the pump and circulation of the water through (adequately /sufficiently) sized pipes that determines the (number /quantity)of radiators you can have. But the total (output /production) of all the radiators, pipes, and cylinders determines the size of the boiler.

II. Speaking Exercises:

Exercise 1. Learn the definitions: boiler; fire-tube boilers; water-tube boilers: furnace

boiler -a strong metallic vessel, usually of wrought iron plates riveted together, or a composite structure variously formed, in which steam is generated for driving engines, or for heating, cooking, or other purposes.  

Fire tube boiler-is a type of boiler in which hot gases from a fire pass through one or more tubes running through a sealed container of water.  

Water tube boileris a type of boiler in which water circulates in tubes heated externally by the fire.

Furnace - an enclosed chamber in which heat is produced to generate steam, destroy refuse, smelt or refine ores, etc.

Exercise 2. Ask questions to the given answers:

1) Question: ___________________________________?

Answer: Boilers that operate higher than 15 psig (pounds per square inch, gauge) are called "high-pressure" boilers.

2) Question: ___________________________________?

Answer: But the total output of all the radiators, pipes, and cylinders determines the size of the boiler.

3) Question: ___________________________________?

Answer: In fire-tube boilers, combustion gases pass through the inside of the tubes with water surrounding the outside of the tubes.

4) Question: ___________________________________?

Answer: In a water-tube boiler the water is inside the tubes and combustion gases pass around the outside of the tubes.

III. Writing exercises:

Exercise 1. Complete the sentences with the suggested words: design; through; furnace; mud drum; produced.

A water-tube 1 is the exact opposite of a fire-tube. Here, the water flows 2 the tubes and is encased in a 3 in which the burner fires. These tubes are connected to a steam drum and a 4. The water is heated and steam is 5 in the upper drum.

Exercise 2. Compose a story on one of the topics (up to 100 words):

“Boiler Types and Classifications”

“Fire-tube boilers”

“Water-tube boilers”

Lesson 7

Read the text: Combustion chambers.

A combustion chamber is the part of an engine in which fuel is burned. The hot gases produced by the combustion occupy a far greater volume than the original fuel, thus creating an increase in pressure within the limited volume of the chamber. This pressure can be used to do work, for example, to move a piston on a crankshaft or a turbine disc in a gas turbine. The energy can also be used to produce thrust when directed out of a nozzle as in a rocket engine.

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