Phrases & word combinations to the text

EXERCISES

TASK 1. Answer the questions:

1. Why did not science and engineering develop very much during the Middle Ages? __________________________________________________________________

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2. Do technical achievements appear at once? _____________________________

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3. Were the technological developments of that time far behind the flight of ideas from Leonardo da Vinci's famous notebooks? _____________________________

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4. What had happened throughout the seventeenth and eighteenth centuries? _____

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5. Who was Denis Papin? What have you known about him? __________________

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6. What does Papin’s “bone-digester” look like? ____________________________

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7. How did Papin introduce his bone-digester to the scientists of the Royal Society? ___________________________________________________________

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8. How did his invention become known throthout the world? ________________

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9. How did a really efficient prime mover appear? __________________________

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10. Were Newcomen machines the only practical steam-engines from the early to the late eighteenth century? ____________________________________________

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TASK 2. Translate the passage from “Throughout the seventeenth and eighteenth centuries …” to “ … technical progress was so slow and inven­tive ideas so rare. ” in the written form.

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TASK 3. Match the equivalents:

Сondensation, bone-digester, investigations, steam-engine, superstitious, Century of Inventions, succession, craftmanship, electricity, available

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электричество

костеварка

паровая машина

суеверный

исследования

последовательность

ремесло

век изобретений

доступный

конденсация

TASK 4. Fill in the blanks with words and word combinations from the text:

Papin's ___________________________, as he called his machine, worked on the ______________________ that when water or juice is boiled in a hermetically closed _____________________ so that the steam cannot escape, the ___________________ increases so much that the steam is heated far beyond the ___________________ of water. The superheated steam helps to cook the ______________________ much faster and more thoroughly than is possible in ordinary _________________________.

TASK 5. Continue the sentenses according to the text:

1. We must try to visualize these circumstances if__________________________

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2. Apart from the incentive to the_______________________________________

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3. From these five thousand pages______________________________________

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4. It was an odd succession of__________________________________________

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5. The super­heated steam helps to_______________________________________

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6. A political event of great importance__________________________________

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7. It was a complicated and rather_______________________________________

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8. A few miles down the river__________________________________________

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9. In the same year an ironmonger______________________________________

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10. Newcomen machines were__________________________________________

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TASK 6. Translate into English:

Он построил экспериментальную модель в Марбурге. Это была сложная и довольно неуклюжая машина, чья энергия происходила больше из атмосферного давления, чем из мощности расширения пара; работник должен был приводить в действие печь через определенные интервалы времени, чтобы производить пар и выключать ее снова, чтобы вызывать конденсацию.

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TASK 7. Give a short summary of the text.

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TASK 8. Give annotation of the text.

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TASK 9. Give your own opinion on the text.

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TEXT 2

THE STEAM TURBINE

The steam-turbine must be a much more efficient and powerful prime mover than the reciprocating engine be­cause it must shortcut the complicated process of con­verting steam energy into rotary motion via reciprocating motion. But the problems involved in building such a ma­chine seemed formidable, especially that of high-precision engineering.  It was only towards the end of the nine­teenth century that engineering methods were developed highly enough for a successful attempt.

Two men undertook it almost simultaneously. The Swedish engineer, Gustaf Patrik de Laval, built his first model in 1883. He made the steam from the boiler emerge from four stationary nozzles arranged around the rim of a wheel with a great number of small inch, de Laval turbine wheel rotated at up to 40, 000 revolutions per min­ute. He supported the wheel on a flexible shaft so that it would adjust itself to fluctuations of pressure — which, at such speeds, would have broken a rigid shaft in no time.

De Laval geared an electric generator to his turbine after he had succeeded in reducing the speed of rotation to 3, 000 r. p. m. His turbo-generator worked, but its capac­ity was limited, and it was found unsuitable for large-scale power stations.

In 1876 Charles Parsons began to work on the idea of a steam-turbine, for which he forsaw a wide range of applications. The reciprocating steam-engine, which was unable to convert more than 12 per cent of the latent energy of coal into mechanical power, was not nearly effi cient enough for the economical generation of electricity energy leaked out right and left from the cylinder, and the condenser.

As he studied the problem he understood that the point where most would be turbine inventors  had been stumped was the excessive velocity of steam. Even steam at a com­paratively low pressure escaping into the atmosphere may easily travel at speeds of more than twice the velocity of sound — and high-pressure steam may travel twice as fast again, at about 5, 000 feet per second.

Parsons had the idea of reducing the steam pressure and speed, without reducing efficiency and economy, by causing the whole expansion of the steam to take place in stages so that only moderate velocities would have to be reached by the turbine wheels. This principle still forms the basis of all efficient steam-tirbines today. Parsons put it into practice for the first time in his model of 1884, a little turbine combined with an electric gen­erator, both coupled without reducing gear and revolving at 18, 000 r. p. m. The turbine consisted of a cylindrical rotor enclosed in a casing, with many rings of small blades fixed alternately to the casing and to the rotor.

It was a more complicated solution of the problem than de Laval, but it proved to be the right one. The speed of 18, 000 r. p. m. used the energy of the steam very well, anci the generator developed 75 amperes output at 100 volts. The little machine, built in 1884, is now at the Science Museum.

Parsons expected, and experienced, a good deal of opposition — after all, there were enormous vested in­terests in the manufacture of reciprocating steam-engines. He began to build some portable turbo-generators, but there were no buyers. Strangely enough, a charity event created the necessary publicity for the turbine. In the winter of 1885-1886, a pond froze over, and a local hospi­tal decided to raise funds  by getting young people to skate on the ice and charging for admission.

The event was a great success, and the newspapers wrote about it. The next step was that the organizers of the Newcastle Exhibition of 1887 asked Parsons to supply the current for its display of electric lighting. Parsons, who died in 1931 at the age of 76, lived long enough to see one of his turbines producing more than 200, 000 kW. He also suceeded in introducing his steam-turbine as a new prime mover in ship propulsion.

The steam which drives them in the power stations may be raised by coal, oil, natural gas, or atomic energy — but it is invariably the steam-turbine which drives the generators; Diesel-engines are the exceptions, and are only used where smaller or mobile stations are required and no fuel but heavy oil is available. Steam-turbines, large or small, run at much lower speeds than Parson's first model, usually at 1, 000 — 3, 000 r. p. m.

When, a quarter of a century after Charles Algernon Parsons's death, the first nuclear power station in the world started up, his steam-turbines were there to convert the heat from the reactor into mechanical energy for the generators.