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.

PHRASES & WORD COMBINATIONS TO THE TEXT

1. especially that of high-precision engineering – особенно проблемы, связанные с созданием устройств высокой точности

2. most would-be turbine inventors – большинство мечтавших изобрести турбину

3. a local hospi­tal decided to raise funds – местная больница решила извлечь выгоду

EXERCISES

TASK 1. Answer the questions:

1. What is the steam turbine? ______________________________________

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2. Were engineering methods developed highly enough for that time? __________

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3.Who undertook it simultaneously? _____________________________________

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4. Who 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? __________

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5. Did De Laval gear an electric generator to his turbine? Was it succesful? ______

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6.Who forsaw a wide range of applications on the idea of a steam-turbine? ______

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7.Whose steam turbines were there to convert the heat from the reactor into mechanical energy for the generators? ___________________________________

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8. Were there any in­terests in the manufacture of reciprocating steam-engines? ___

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9. Did the organizers of the Newcastle Exhibition of 1887 ask Parsons to supply the current for its display of electric lighting? ______________________________

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10.When the first nuclear power station in the world started up? ______________

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TASK 2. Translate the passage from “ Two men undertook …” to “…  a rigid shaft in no time ” in the written form.

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TASK 3. Fill in the blanks with words and word combinations from the text:

As he studied the ______________ he understood that the point where most would be _________________ had been stumped was the __________________ of steam. Even steam at a _________________ escaping into the atmosphere may easily travel at speeds of more than twice the ________________________ — and high-pressure ___________________ may travel twice as fast again, at about 5,000 feet per second. Parsons had the ___________________ the steam pressure and speed, without ____________________, by causing the whole expansion of the steam ____________________ in stages so that only moderate _________________ would have to be reached by the _________________. This principle still forms the basis of all ____________ today.

TASK 4. Translate into English:

У Парсона возникла идея, уменьшить давление и скорости, не уменьшая эффективности и экономичности, путем полного расширение пара, чтобы колесами турбины были достигнуты умеренные скорости.

Эти формы составляли основу эффективности паровых турбин и были выпущены Парсоном на практику впервые в 1884.

Небольшая турбина объединялась с электрическим генератором, не уменьшая вращения. Турбина состояла из цилиндрического ротора, приложенного к корпусу с кольцами небольших лопастей, установленных в корпусе.

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