6. Decide which statements are true and which ones are false.

1. A modern boiler generally consists of a circuit of metal tubes which is placed and arranged to present a maximum surface to a heat source, usually a combustion chamber.

2. Intermediate–size boilers are designed to match the demands of domestic heating systems.

3. Compact units are also required to produce steam for industrial use as a process–energy source.

4. Many space–heating systems utilize steam as a heat–circulation medium, but some systems are designed to use hot water as a medium.

5. The energy for most boilers is provided by the combustion of wood, oil, and gas.

6. The most important part of a boiler is the area where water absorbs energy to become steam.

7. In water–tube boilers the water is passed through metal tubes, which are heated either by convection and conduction from the hot combustion gases or by direct radiation from the fire.

8. All modern boilers are under complete automatic control.

7. Complete the following sentences by adding the phrases given in part b.

Part A.

1. Boilers range in size and function from the compact units in domestic heating systems to 20–story complexes…

2. A wide range of intermediate–size boilers are designed to match the demands of steam engines…

3. Other fuels such as wood, waste gases from industrial processes, and solid wastes such as…

4. Fire–tube boilers are limited to relatively low operating…

5. All boilers must be provided with equipment such as…

Part B

A. … bagasse (from sugarcane), sawdust, and even trash and garbage serve as energy sources to a limited extent.

B. ... pressures because of the difficulty of constructing a shell strong enough to with stand the high pressure required for efficient operation.

C. ... that drive giant steam turbines for electrical power production.

D. ... safety valves, water level controls, indicating gauges, and provision for rapid cutoff of fuel combustion and accessory equipment.

E.... and steam turbines in stationary, marine, and locomotive applications.

8. Answer the questions on the text.

1. What is a boiler?

2. Where is fuel burned?

3. What integrated complex may be called a boiler, a steam plant, or a steam generator?

4. What do boilers range in?

5. What are boilers designed and required to?

6. What is utilized as a heat–circulation medium in space–heating systems?

8. The energy for most boilers is provided by the combustion of wood, waste gases and solid wastes such as bagasse , sawdust, and even trash, isn’t it?

9. What is the most important part of any boiler?

10. How do water–tube boilers function?

11. Why are fire–tube boilers limited to relatively low operating pressures?

12. What kind of boilers are preferable for domestic and small industrial heating systems?

13. What equipment all boilers must be provided with?

14. The efficiency of modern boilers is extremely high, isn’t it?

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