раб 3 вар 5 Boiler make-up water treatme

Вариант 5
I. Перепишите следующие предложения, определите в каждом из них видо-временную форму и залог сказуемого. Переведите предложения на русский язык.
1. Much attention is being paid to the development of three-dimensional television.
2. Our specialists had workers out a new flexible line some month ago.
3. The tests were being carried out well.
4. Many graphics programs are controlled by a mouse or some other device.
II. Перепишите следующие предложения и переведите их на русский язык, обращая внимание на разные значения слов it, that, one.
1. It is necessary to obtain accurate data on the possibility of living and working in space.
2. The peoples know that their joint efforts can secure peace in the whole world.
3. We had to find new methods of investigation because the old ones were unsatisfactory.
III. Перепишите следующие предложения и переведите их на русский язык, обращая внимание на разные значения глаголов to be, to do, to have.
1. A programme for the construction of new types of spaceships is to be carried out this year.
2. This device does help them a lot in their work.
3. We had to change the design of this machine.
4. The speed of electrons is almost the same as that of light.
IV. Перепишите следующие предложения и переведите их на русский язык, обращая внимание на бессоюзное подчинение.
1. We know electricity produces heat.
2. The new materials the Russian chemists developed were used in space technology.
V. Перепишите следующие предложения и переведите их на русский язык, определите функцию инфинитива.
1. It is necessary for Russian specialist to know a foreign language.
2. Our idea was to design a new device for automatic control.
3. To increase the productivity of labour one must use the methods we have just described.
VI. Перепишите и письменно переведите предложения на русский язык. Обратите внимание на правила перевода объектного и субъектного инфинитивного оборотов.
1. We know him to have been an excellent portrait painter.
2. We knew the report to have consisted of two parts.
3 Light and radio waves are said to be of similar nature.
4. The laser beam seems to have almost unlimited industrial possibilities.
VII. Прочитайте перепишите и письменно переведите на русский язык текст.
Boiler make-up water treatment plant and storage
Since there is continuous withdrawal of steam and continuous return of condensate to the boiler, losses due to blowdown and leakages have to be made up to maintain a desired water level in the boiler steam drum. For this, continuous make-up water is added to the boiler water system. Impurities in the raw water input to the plant generally consist of calcium and magnesium salts which impart hardness to the water. Hardness in the make-up water to the boiler will form deposits on the tube water surfaces which will lead to overheating and failure of the tubes. Thus, the salts have to be removed from the water, and that is done by a water demineralising treatment plant (DM). A DM plant generally consists of cation, anion, and mixed bed exchangers. Any ions in the final water from this process consist essentially of hydrogen ions and hydroxide ions, which recombine to form pure water. Very pure DM water becomes highly corrosive once it absorbs oxygen from the atmosphere because of its very high affinity for oxygen.
The capacity of the DM plant is dictated by the type and quantity of salts in the raw water input. However, some storage is essential as the DM plant may be down for maintenance. For this purpose, a storage tank is installed from which DM water is continuously withdrawn for boiler make-up. The storage tank for DM water is made from materials not affected by corrosive water, such as PVC. The piping and valves are generally of stainless steel. Sometimes, a steam blanketing arrangement or stainless steel doughnut float is provided on top of the water in the tank to avoid contact with air. DM water make-up is generally added at the steam space of the surface condenser (i.e., the vacuum side). This arrangement not only sprays the water but also DM water gets deaerated, with the dissolved gases being removed by a de-aerator through an ejector attached to the condenser.