Упражнения

Упр.1. Найдите в тексте английские эквиваленты следующих слов и словосочетаний:

1. Установить сварочное оборудование; 2. науглероженное пламя; 3. комплект переносного оборудования; 4.тележка для перевозки газовых баллонов; 5. регулировать давление; 6. специфический запах; 7. зажигать, воспламеняться; 8. загрузочный механизм; 9. плавкий предохранитель; 10. соединительная гайка

Упр.2. Дайте русские эквиваленты следующих слов и словосочетаний:

1. Oxyacetylene welding; 2. to secure the equipment; 3. fixed location; 4. master regulator; 5. toolbox; 6. generating unit; 7. proper precautions; 8. inner cone tip; 9. to prevent excessive pressure; 10. a built-in part of the generator

Упр.3. Переведите следующие предложения на английский язык:

1. В комплект оборудования входит набор гаечных ключей для регулирования разных соединений, имеющихся на баллонах, редукторах и горелках. 2. Избыток ацетилена в науглероженном пламени приводит к его разложению на углерод и водород. 3. Кислород подается к месту сварки по трубопроводу с выходами для каждого рабочего места. 4. Баллоны крепятся к тележке цепями.5. В ходе реакции получения ацетилена выделяется большое количество тепла. 6. Ацетилен находится в баллонах в виде раствора в ацетоне под давлением 254 psi . 7. Плавкий предохранитель- это отверстие, заполненное сплавом металла с температурой плавления примерно 100 º. 8 Сварочное пламя имеет сложную структуру, и качество сварки во многом зависит от правильности его регулирования. 9. Для получения ацетилена карбид кальция добавляют к воде через загрузочный бункер со скоростью, которая поддерживает рабочее давление оборудования. 10. Окислительное пламя получается при избытке кислорода, а науглероживающее – при его недостатке.

Unit 48. OXYGEN AND ITS PRODUCTION

Oxygen is a colorless, tasteless, odorless gas that is slightly heavier than air. It is nonflammable but will support combustion with other elements. In its free state, oxygen is one of the most common elements. The atmosphere is made up of approximately 21 parts of oxygen and 78 parts of nitrogen, the remainder being rare gases. Rusting of ferrous metals, discoloration of copper, and the corrosion of aluminum are all due to the action of atmospheric oxygen, known as oxidation.

Oxygen is obtained commercially either by the liquid air process or by the electrolytic process. In the liquid air process, air is compressed and cooled to a point where the gases become liquid. As the temperature of the liquid air rises, nitrogen in a gaseous form is given off first, since its boiling point is lower than that of liquid oxygen. These gases, having been separated, are then further purified and compressed into cylinders for use. The liquid air process is by far the most widely used to produce oxygen. In the electrolytic process, water is broken down into hydrogen and oxygen by the passage of an electric current. The oxygen collects at the positive terminal and the hydrogen at the negative terminal. Each gas is collected and compressed into cylinders for use.

Always refer to oxygen as oxygen, never as air. Combustibles should be kept away from oxygen, including the cylinder, valves, regulators, and other hose apparatus. Oxygen cylinders and apparatus should not be handled with oily hands or oily gloves. Pure oxygen will support and accelerate combustion of almost any material, and is especially dangerous in the presence of oil and grease. Oil and grease in the presence of oxygen may spontaneously ignite and burn violently or explode. Oxygen should never be used in any air tools or for any of the purposes for which compressed air is normally used.

A typical oxygen cylinder is made of steel and has a capacity of 220 cu ft at a pressure of 2000 psi (13,790 kPa) and a temperature of 70ºF (21ºC). Attached equipment provided by the oxygen supplier consists of an outlet valve, a removable metal cap for the protection of the valve, and a low melting point safety fuse plug and disk. The cylinder is fabricated from a single plate of high grade steel so that it will have no seams and is heat treated to achieve maximum strength. Because of their high pressure, oxygen cylinders undergo extensive testing prior to their release for work, and must be periodically tested thereafter.

The gases compressed in oxygen and acetylene cylinders are held at pressures too high for oxyacetylene welding. Regulators reduce pressure and control the flow of gases from the cylinders. The pressure in an oxygen cylinder can be as high as 2200 psi (15,169 kPa), which must be reduced to a working pressure of 1 to 25 psi (6.90 to 172.38 kPa). The pressure of acetylene in an acetylene cylinder can be as high as 250 psi (1724 kPa) and must be reduced to a working pressure from 1 to 12 psi (6.90 to 82.74 kPa). A gas pressure regulator will automatically deliver a constant volume of gas to the torch at the adjusted working pressure.

The regulators for oxygen, acetylene, and liquid petroleum fuel gases are of different construction. They must be used only for the gas for which they were designed. Most regulators in use are either the single stage or the two stage type. Check valves must be installed between the torch hoses and the regulator to prevent flashback through the regulator. The single stage oxygen regulator reduces the cylinder pressure of a gas to a working pressure in one step. The single stage

oxygen regulator mechanism has a nozzle through which the high pressure gas passes, a valve seat to close off the nozzle, and balancing springs. Some types have a relief valve and an inlet filter to exclude dust and dirt. Pressure gauges are provided to show the pressure in the cylinder or pipe line and the working pressure.

In operation, the working pressure falls as the cylinder pressure falls, which occurs gradually as gas is withdrawn. For this reason, the working pressure must be adjusted at intervals during welding operations when using a single stage oxygen regulator.

The oxygen regulator controls and reduces the oxygen pressure from any standard commercial oxygen cylinder containing pressures up to 3000 psi. The high pressure gauge, which is on the inlet side of the regulator, is graduated from 0 to 3000 p s i . The low or working pressure gauge, which is on the outlet side of the regulator, is graduated from 0 to 500 psi.

A single stage oxygen regulator consists of a flexible diaphragm, which controls a needle valve between the high pressure zone and the working zone, a compression spring, and an adjusting screw, which compensates for the pressure of the gas against the diaphragm. The needle valve is on the side of the diaphragm exposed to high gas pressure while the compression spring and adjusting screw are on the opposite side in a zone vented to the atmosphere.

The two stage oxygen regulator is similar in operation to the one stage regulator, but reduces pressure in two steps. On the high pressure side, the pressure is reduced from cylinder pressure to intermediate pressure. On the low pressure side the pressure is reduced from intermediate pressure to work pressure. Because of the two stage pressure controls, the working pressure is held constant, and pressure adjustment during welding operations is not required.

VOCABULARY

Nonflammable – невоспламеняющийся, негорючий

Discoloration – обесцвечивание, потеря цвета

Liquid air process – сжижение воздуха

Electrolytic process=electrolysis - электролиз

Combustibles – горючие вещества

Air tools – пневматический инструменты

Removable metal cap – съемный металлический колпачок

Plate of steel – стальной лист

To heat-treat – закаливать, подвергать тепловой обработке

Extensive testing – усиленный \ многосторонний контроль

Regulator - редуктор

Single/two-stage regulator – одно\двухкамерный редуктор

Flashback – обратный удар пламени (в шланг или баллон)

To close off – перекрыть, отключить

Diaphragm - мембрана

Balancing/compensating spring – уравновешивающая пружина (редуктора)

Relief valve – предохранительный \ разгрузочный клапан

Compression spring – нажимная пружина

Vented – имеющий выход

glass wool filter – фильтр из стекловолокна

to bear down - передаваться

stirrup – хомут, скоба

set pressure – заданное давление