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Modern Uses of Oxygen
Although oxygen has been used in industry for more than 100 years, there has been interest in this colourless, odourless, tasteless gas for several' hundred years. Its presence as an active element in the air was suspected as long ago as 1500 A. D., but only in 1777 Antoine Lavoisier, a French chemist, named oxygen and described its properties.
The actual development of the industrial application of oxygen for the next hundred years was extremely slow. Then, at the turn of the twentieth century, two factors greatly speeded progress. One was a method for economically producing oxygen of high purity from the air, and the other was a method for producing calcium carbidc on a commercial scale.
Probably 95 per cent of the huge volume of oxygen used today is obtained from the air by a process which was developed by Dr. Carl von Linde in Germany in 1895 and 1902. This method is based upon the liquefaction of air and its fractional distillation. Technically, the process is complicated, as it requires one of the lowest temperatures used industrially — more than 300°F below zero (-194.4eC). The liquid air is a very cold mixture of liquid oxygen and liquid nitrogen. Oxygen is then separated by rectification. Most oxygen produced for industrial purposes is purer than 99 per ccnt.
Calcium carbidc treated with water produces acctylcnc, a gas which burns in air with a brilliant white light. When the two gases, oxygen and acctylcnc are mixed in proper proportions and burned, their combustion produces the hottest flame known — more than 5400°F (» 3000°C). This flame for the past 100 years has formed the basis for the oxy-acctylcnc process for welding and cutting metals.
Today there is practically no industry which does not use the process. Broadly speaking, applications are divided into two fields — repair and production. The repair field is perhaps the better known, for practically every garage uses the oxy-acctylcnc process for repairing automobile parts.
In industry, there is not a factory which does not use the process in many different ways for repairing the equipment.
Another process where acetylene is used, is called “hard-facing”*. Extremely hard alloys are applied to the surfaces of metal parts, increasing the life of the parts many times.
Certain industries have developed mostly due to welding. This is true in the manufacture of airplanes, automobiles, refrigerators, railway roads.
But the greatest amount of oxygen is used in cutting iron and steel — one of the most spectacular applications of oxygen in industry. This simple process has literally revolutionized the metalworking industries. It was found that any cuts were made quite easily.
* hard-facing — покрытие твердым слоем, улрочненне поверхности
One of the most recent applications of the oxy-acctylcnc process is for removing surface defects from steel. In this way, larger amounts of cleaner and better steel are made possible at lower cost.
Although by far the greatest volume of oxygen— amounting to several billion cubic feet a year— is used for industrial puiposcs, an ever increasing amount of oxygen is being used in mcdicinc, the treatment of diseases, such as pneumonia or heart diseases. It has saved many lives. Besides, while breathing oxygen, aircraft pilots operate at altitudes otherwise impractical without it.
It may be said that oxygen is men’s best friend— both in industry and for human health.
Words and Word-Combinatlons to Be Memorized
acetylene, actual, amount, apply, base, below, besides, bum, calcium, carbide, commercial, complicated, development, distillation, divide, equipment, ever, extremely, factor, foot (feet), fractional, human, interest, iron, liquid, manufacture, mix, nitrogen, operate, past, possible, practically, presence, process, production, proportion, recent, scale, separate, speed, steel, taste, tasteless, technically, temperature, than, true, at the turn of the ccntuiy, while
Ex. 6. Give the Uzbek equivalents for the following:
long ago, more than, less than, industrial application, extremely slow, at the turn of the twentieth ccntuiy, speed progress, high, purity, on a commercial scale, huge volume, obtain by a process, develop a process, liquid air, separate, for industrial purposes, treat with smth., mix in proper proportions, form the basis for smth., automobile parts, the metalworking industries, remove a dcfcct, treat a disease, breathe oxygen
Ex. 7. Give the English equivalents for the following:
Faol element, sanoat miqyosida, ehtimol, havodan olingan kalsiy karbidi usulni ishlab chiqadi, fraksiyali distillash, eng past harorat, noldan past, noldan yuqori, suyuq havo, sanoat maqsadlari uchun, havoda bir hovuch, bo'lingan, metall qismlarga , eng katta miqdordagi oddiy jarayon, shuning uchun insonning eng yaxshi do'sti bo'lishi mumkin.
Ex. 8. Fill in the blanks with prepositions where necessary.
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