III. Select the correct phrase out of the phrases given in the right-hand column to complete each statement from the left hand column. Translate the completed sentences into Russian.

1. A steam turbine is a prime mover which …       . 2. The blades serve for converting … . 3. The rotor is the rotating part which ….  4. The turbine rotor, as carrier of blades transmits the mechanical energy impulses on the running blades…      . 5. The moving blades are mounted in the grooves …    .

a. carries the blades or buckets.  b. in the form of rotational energy to the driven machinery. c. converts heat energy into mechanical energy. d. made on the rotor. e. the thermal energy of the steam into mechanical energy.

IV. Answer the following questions.

1. What is a stage in a steam turbine?

2. What are four types of turbine seals?

3. What are the two basic types of steam turbines?

4. What is the operating principle of an impulse turbine?

5. What is the operating principle of a reaction turbine?

 

V. Translate into English.

1. Турбина состоит из следующих основных частей: корпуса (цилиндра) с направляющими (сопловыми) аппаратами, обоймами, диафрагмами и уплотнениями; ротора; подшипников; соединительных муфт; валоповоротного устройства; системы смазки, регулирования и защиты.

2. К статору турбину относятся корпус, обоймы для установки и крепления диафрагм и диафрагмы.

3. Для размещения направляющих лопаток, образующих сопловые каналы и обеспечивающих эффективный вход пара на рабочие лопатки служат диафрагмы.

4. В современных мощных турбинах используют два типа диафрагм: литые и сварные.

5. Одним из самых ответственных элементов корпуса является паровпуск, через который поступает пар.

ВАРИАНТ 3

I. Translate into Russian.

REDUCTION GEARS AND COUPLINGS

Steam turbines must operate in a relatively high rpm range for greatest efficiency while propellers operate most efficiently in a relatively low rpm range. One means of accomplishing the necessary step down from high turbine shaft rpm to lower propeller shaft rpm is by use of an electric drive. The most common means of obtaining the required propeller rpm for ship propulsion is by use of reduction gears.

The use of reduction gears is by no means limited to ship propulsion. Other steam turbine-driven machinery such as ship’s service generators, air compressors, and various pumps also have reduction gears. In these, as in ship propulsion units, turbine operating efficiency requires a higher rpm range than that suitable for the driven unit.

Reduction gears are classified by the number of steps used to bring about the speed reduction and the arrangement of the gearing. There are single and double reduction gears,although double reduction is more usual.

Since the shaft (rotor) is made in small parts due to forging limitations and other technological and economic reasons, the couplings are required between any two rotors. This coupling permits angular misalignment, transmits axial thrust and ensures axial location.

The types of couplings generally employed in power plants are:

· Flexible coupling

· Solid shaft coupling

II. Read the following definitions in column A and find the corresponding terms which they explain. Translate the completed sentences into Russian.

1. This is a system of gears where one or more wheels travel around the outside or inside of another wheel whose axis is fixed. 2. It is an arrangement by which an input speed can be lowered for a requirement of slower output speed, with same or more output torque. 3. This unit is usually known as reduction gear box. 4. This arrangement consists of only one pair of gears. 5. This arrangement is generally used in applications involving very high speeds. In this arrangement the pinion is connected to the input shaft using a flexible coupling.

A.The reduction gear assembly   B. Double Reduction gear   C. Reduction Gear   D.Single Reduction gear   E. Epicyclical gearing.

 

 

⇐ Предыдущая123Следующая ⇒

Поделиться: