Unit VII. The Infinitive

Famous People

Furnace

Furnace is a part of steam generating unit in a fossil-fuel steam power plant. It is a well-insulated space in which gas, oil, pulverized coal or combustible gases may be burned with complete combustion. Fuel is burned inside the furnace, creating hot gas which heats up water in the steam-generating tubes (the water filled tubes that make up the walls of the furnace to generate steam). There can be more than one burner in a furnace. The major function of the furnace is providing space in which the fuel may be burned with a minimum loss. In some services, the steam reenters the furnace through a superheater in order to become superheated. Superheated steam is used in driving turbines. Since water droplets can severely damage turbine blades, steam is superheated to 730°F (390°C) or higher in order to ensure that there is no water in the steam.

The design of a furnace is based upon the “three T’s of combustion”: temperature, turbulence, and time.

For each particular fossil fuel, there is a minimum temperature, known as the ignition temperature, at which the combustion of that fuel takes place with the proper amount of air. In burning fuels such as gas, oil, or pulverized coal, the incoming fuel-air mixture must be heated above the ignition temperature. If the fuel is cooled below the ignition temperature, it will not burn, regardless of the amount of air present. Therefore a furnace must be large enough and be maintained at a high temperature.

Turbulence is essential if combustion is to be complete in a furnace of economical size. Violent mixing of oxygen with the combustible gases in a furnace increases the rate of combustion, shortens the flame and reduces the required furnace volume. Turbulence is obtained, in the case of oil, gas, and pulverized coal, by using burners with a violent whirling action. High-velocity steam air jets may be used to increase the turbulence in furnaces fired with coal.

Since combustion is not instantaneous, time must be provided for the oxygen to react with the fuel in the furnace. Gaseous fuels burn very rapidly when thoroughly mixed with air. Oil and pulverized coal burn longer.

Furnace designs depend therefore on its function, type of fuel and method of burning the fuel as well as introducing combustion air. However, all furnaces have some common features.

· Transcribe the following words, practice reading them, give Russian equivalents:

Furnace, insulated, combustible, combustion, burn, turbulence, ignition, violent, whirling, instantaneous, pulverized, mixture, design, reenter, ensure

· Are the following sentences true or false? Correct the false sentence.

1. Three T-s of combustion are: temperature, turbulence, transmission.

2. Combustion takes place below the ignition temperature.

3. Turbulence helps the mixing process between the fuel and oxygen.

4. Combustion in furnaces is always slow.

5. More time is needed to burn coal than to burn gases.

6. The furnace designs depend on many factors.

· Use the following paragraphs to answer these questions:

Paragraph 1

Where can furnaces be used? What is the major function of a furnace?

Paragraph 3

What is ignition temperature?

Paragraph 4

What is the use of turbulence? How can turbulence be obtained?

Paragraph 5

What kinds of fuels burn faster?

Paragraph 6

What factors does furnace design depend on?

Robert Boyle (1627-1691)

Robert Boyle was one of the leading intellectual figures of the seventeenth century who is often referred to as the father of modern chemistry. He also made important contributions to physics and is best known for Boyle's law (sometimes called Mariotte's Law) describing an ideal gas. He was a dedicated experimenter. He made studies of combustion and proved that flame required air. He investigated the propagation of sound and showed that sound did not travel in a vacuum. Boyle made a wide variety of experiments with his vacuum pump. Although he was especially noted for his experimental work, Boyle also contributed to physical theory. He deeply believed in the atomic theory of matter, which he called the corpuscular philosophy, and used it to explain many of his experimental results. Boyle argued against Aristotle's view of the four elements of earth, air, fire and water. He argued that matter was composed of corpuscles which themselves were differently built up of different configurations of primary particles. Boyle's scientific range was wide. During the course of his life he worked constantly to improve the life of humanity. He was interested in the improvement of agricultural methods, in the improvement of medicines and medicinal practice, in the possibility of preserving food by vacuum packing, and other useful things.

Read the following sentences. State the voice and the tense forms of the predicates. Find the infinitive in each sentence and explain the use of it. Translate the sentences into Russian.

1. The material to be attacked by X-rays is placed on the screen.

2. The method to be chosen in any particular case depends on many factors.

3. The object to be detected is placed on one side of the lens.

4. We multiply volts by amperes to obtain the number of watts.

5. To determine the composition of this substance is of great importance for us.

6. To determine the composition of this substance we always use this reaction.

7. In order to understand this phenomenon the laws of motion should be considered.

8. To explain the pressure of gases and their diffusion we must take into consideration that all substances are made of molecules.

9. He was the first to determine the thermal conductivity of this substance.

10. The problem to be considered next deals with the loss of heat in the pipeline.

11. To understand this problem you must read this article.

12. To understand this problem is impossible.

13. To answer this question we studied a lot of publications.

14. To make this experiment without special equipment is absolutely impossible.

15. Hero of Alexandria was the first to invent a steam engine.

· Read the following text. Find the predicate in each sentence and state the voice and the tense form. Which of the sentences contain infinitives?Translate the text into Russian.

Дата добавления: 2017-02-01; Просмотров: 71; Нарушение авторских прав?; Мы поможем в написании вашей работы!