Wood and the technology of wood drying (Древесина и технологии сушки древесины). Учебно-методическое пособие

Section 2.

REVISION GRAMMAR EXERCISES

1. Translate the following sentences paying attention to the Subject, Predicative and Object clauses:

1.It is no doubt that the word “figure” has several equivalents in Russian.

2.It is desirable that students should memorize the new words from the text “Methods of Drying Timber”.

3.Why they didn’t reach an agreement last year is not clear to anyone.

4.The problem was whether we could carry out all necessary tests in time.

5.This is what we were talking about.

6.He found it important that they should start as soon as possible.

7.It was necessary that an investigation should be made into the matter.

8.It was clear that something had happened.

9.That we need more people in math and science is clear to all.

10.His only desire was that life should fall in with his own plans.

11.Students were told that their home task was to learn the new words from the second part of the text “Methods of drying timber”.

2. Change the following sentences into Indirect speech. Mind the Sequence of Tenses.

Model: He said: “I shall do this work”.

He said that he would do this work.

1.Students asked the teacher: “What text shall we read after we finish reading “Methods of drying timber”.

2.“You have done very badly”, remarked the teacher.

3.They wrote, “It is time we settled the matter”.

4.Jonathan: “I've returned the dictionary to the library”.

5.“I never understand you,” she told me.

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6.“I have been waiting since the morning,” he complained.

7.“How long have you been standing here?” – He asked me.

8.“German is easy to learn”, she said. 9. The speaker said, “Be quiet and listen to my words”.

10.He said: ”He must be telling the truth. I am absolutely sure he is”.

11.“Can I ask you to do me a favour? If you see Martin tell him I need to talk to him, please”, said Dr. Pambrook.

12.He said: “I have finished the work”.

Section 3.

WORD-BUILDING

From base words or stems other words can be built by adding parts at the beginning or at the end. A word part added at the beginning of a word is called a prefix. Prefixes modify the lexical meaning of stems to which they are added. A word part added at the end of a word is called a suffix. Their chief function is to show that a word belongs to a particular class, such as nouns, verbs or adjectives. By adding or by changing a suffix we can change a word from one class to another.

EXERCISES

1. What meaning does the prefix add in each word below?

large – enlarge; round – surround; pass – surpass;

dependent – independent; side – outside, inside; advantage – disadvantage; production – reproduction; talk – crosstalk;

exist – coexist;

clockwise - counterclockwise

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2. By adding one of the suffixes given below, change each word to

a) noun (-er, - sion, -ment, - tion, -ing, -ence):

to listen, to extend, to refine, to enlarge, to compose, to arrange, to introduce, to advance, to reproduce, to separate, to record, to differ, to equip

b) verb (-ize, -ate)

computer, industrial, synthesis, origin

c) adjective (-less, -ent, -ic, -ive, -al, -ible)

bound, depend, base, relate, expenses, effect, origin, create, act, person, convert

d) adverb (-ly)

entire, mere, actual, wide, relative, expensive, active

3. Arrange antonyms in pairs and translate them:

a)large, minimize, left, complex, frequently, variable, benefit, equality, wide, important

b)constant, simple, seldom, maximize, inequality, small, narrow, right, unimportant, disadvantage

Section 4.

CHECK YOUR PROGRESS

1.How can words be built from base words or stems?

2.What is a suffix? A prefix?

3.Characterize the text “Wood-drying kiln”.

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Unit 7

Section 1.

PRE-TEXT EXERCISES 1. Check up if you read these words correctly:

accumulation [əˌkjuː.mjʊˈleɪ.ʃən], evaporate [ɪˈvæp.ər.eɪt], simultaneous [ˌsɪm.əlˈteɪ.ni.əs], trolley [ˈtrɒl.i], redistribute [ˌriː.dɪˈstrɪb.juːt], environment [ɪnˈvaɪə .rən .mənt], permit [pəˈmɪt], guarantee [ˌgær.ənˈtiː], autoclave [ˈɔː.təʊ.kleɪv], whereby [weəˈbaɪ], hazard [ˈhæz.əd], microorganism [ˌmaɪ.krəʊˈɔː.gən.ɪ.zəm], requirement [rɪˈkwaɪə.mənt]

2. Give the initial forms of the following words:

heating, degassing, stages, less, thickness, unloading, delivered, dryer, traditional, provides

3. State to what parts of speech the following words belong:

quality, alternating, necessary, therefore, supply, change, evaporation, impregnation, completely, various, representative, abundance, exactly

4. Check if you remember the following verbal forms correctly:

they have been obtained, they have been prepared, they have been isolated; he would be unable, it would be unknown, it would be excellent; we may add – we might add; we should add – we should have added; it appears; it seems; it is said; it is reported; it is considered

5. Translate the following word groups into Russian:

short production time; intense removal of moisture from timber; electrical heat-generator; loading and unloading wood; the

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surrounding environment; constant final moisture; impregnation material in the filling phase; automated charging system; fully automated control

6. Give the English equivalents for the following Russian words and word combinations:

использовать; сопоставить; особый; обычный; источник; изменять; источник информации; качество сушки; накопление энергии; испарение влаги; сушилка; порода древесины; толщина материала; сердцевина; вакуумная сушилка; процесс термической обработки; низкое давление; основная защита.

TEXT A

VACUUM WOOD DRYER

High quality drying and short production time in this drying chamber are achieved thanks to vacuum-convective wood drying method that consists of alternating degassing and heating stages.

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During heating heat energy accumulation and simultaneous drying takes place. After that degassing starts which is accompanied by intense removal of moisture from timber.

Chamber pressure drop causes moisture evaporation that consequently causes decrease of material temperature. At first evaporation affects upper layers of wood producing temperature gradient that results in up to 60% moisture transfer intensification comparing to conventional convective dryers. That is how this dryer enables you to dry green pine in less than 3 days and oak – in 10 days.

High quality dried wood is obtained due to lack of drying strains that appear at conventional drying processes due to moisture content difference between core and upper layers. Degassing provides intense redistribution of moisture and eliminates these strains. After completion of degassing stage the process repeats. Number of cycles depends on wood species, material thickness and required end moisture content (up to 6%).

Vacuum wood dryer configuration

*1600 mm in diameter 6500 mm long vacuum chamber with a lid and internal equipment;

*operating console;

*electrical heat-generator;

*internal heat exchangers;

*trolley and receiving device for loading and unloading

wood.

Process

The necessary technique for this process is delivered as additional equipment to the WTT vacuum dryer on a turn-key basis. The smoking of the wood thus takes place through supply of ammonia subsequent to drying of the wood.

An obvious advantage of this concept is that the plant is capable of operating with this special equipment while being fully functional as vacuum dryer as well. Even 65 mm oak plants are fully

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through-coloured within 2-3 weeks. That is one-third of the time required in conventional systems, which in addition are not able to guarantee a through-colouring. It is therefore evident that the cost of a WTT through-colouring only constitutes a small part of the costs normally associated with heartwood smoking.

Another significant advantage of the WTT smoking process is that through a fully new post process step, an odourless wood product is available at the end of treatment. Conventional systems require storage of the material in halls with cleaning of the exhaust air. With this new technology, the requirements to the surrounding environment and regulations regarding operational and work safety are fulfilled. An operational permit can therefore be issued after short period.

Vacuum Dryer

Gentle, colour-fast and quicker drying in WTT SSV vacuum dryer. This flawless and strainless drying is suitable for all high value hard woods and big sized soft woods.

In comparison with traditional drying and other vacuum systems, the WTT dryer offers great advantages:

*Big dimensions – 120mm spruce/construction timer is for instance dried from 80-15% in 96 hrs.

*Where quicker delivery and flexibility is important (3-8 times quicker than conventional dryers and other vacuum systems).

*Where wood needs to be dried without tensions and where a very low final moisture content is desired, e.g. 6%.

*For sensitive wood that tends to change colour (100% oxygen-free drying through external condenser).

*Where very constant final moisture content is desired.

[from: http://www.invac.ru/catalogue/pdfs/vd.pdf ;

http://www.ecvv.com/product/3520058.html]

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ASSIGMENTS

1. Explain what the following words and word combinations mean:

-chamber;

-degassing;

-receiving device for loading and unloading wood;

-cleaning of the exhaust air;

-moisture content;

-environment;

-vacuum-convective wood drying.

2.Write a short summary of the text using the topical sentences.

3.Translate into English:

1.Процесс сушки материала состоит из перемещения влаги изнутри материала, парообразования и перемещения влаги с поверхности тепломассообмена в окружающую среду.

2.В первом периоде сушки этот переход осуществляется с преодолением только энергии парообразования жидкости.

3.Во втором периоде накладывается энергия связи жидкости с материалом.

4.Следует отметить, что последовательность уровней и соответствующих им явлений для процесса сушки условна и зависит от коллоидно-физических свойств материала, а также от периода протекания процесса.

4.Read text A again and retell it in your own words.

5.Read and translate text B.

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TEXT B

THERMAL TREATMENT

New heat treatment process results in very durable wood already at low temperatures.

The newly developed heat treatment process is now available with a very effective heat transfer made possible through a heated double casing of the pressurized autoclave in stainless steel. The process is very swift, particularly gentle and commercially feasible. Wear parts like for instance ventilators are not needed in the plant. A specialty of the process is that the wood is not fully dried during the process: a residual moisture content of approximately 6% HF is retained.

The high rate of wood rejection which one often sees with traditional thermo treatment processes, where the wood is completely dried out, is minimized in the WTT process.

The Summary of the Biological Results of Wood:

The wood types pine, fir and spruce were tested with similarly good results (a classification of this result cannot be carried out due to lack of standard till this point of time). The complete examination report should be available very shortly. With the first plants now in operation, calculations can be made regarding processing costs. Normally, hard and soft woods up to 60 mm can be processed within 24 hours, whereby total costs from energy, depreciation and interests lie at a cost level similar to that of “normal” impregnated wood.

WTT thermo treatment plants are turn-key and are delivered inclusive of heating source (electrical/oil/gas/wood chips), automatic charging system and fully automatic control.

Resistance Test of Thermo-Treated Wood

Standardization tests of beech wood that has undergone varied thermo treatment processes. Tests of the wood samples are conducted in earth contact according to ENV 807 for their resistance against

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fungus and other microorganisms found in earth (exposure after 7 weeks in a 32-week long test).

Low Pressure/Double Vacuum Impregnation

WTT double vacuum process for impregnation of dimensionally stable components like, e.g. window frames, doors, and garden furniture. In this plant the timber is preserved with organic wood preservatives (either water emulsion or organic solvent based) in a vacuum/low pressure process for hazard classes1-2. Through double vacuum impregnation, a basic protection is given to the wood at a fairly low pressure of up to 2 bar. WTT low pressure plants work with approximately 95% vacuum and a particularly quick filling in order to achieve better control of the absorbed wood preservative agent and to avoid excess uptake of impregnation material in the filling phase.

[from http://www.wtt.dk]

6.Summarize the general ideas developed in both texts of the Unit.

7.Translate into English:

1.Древесина – сложная многофазная система с ярко выраженной анизотропией, состоящая из твердой фазы – скелета древесного вещества, жидкой фазы – воды, находящейся в связанном и свободном состояниях, и газообразной фазы – паровоздушной смеси, заполняющей часть пор древесины, которая не занята водой.

2.Теория теплопроводности таких материалов еще мало разработана.

3.Материалы такого рода в отношении теплопроводности нельзя рассматривать как твердое тело.

4.Процесс сушки пиломатериалов сопровождается возникновением и развитием внутренних напряжений в древесине, которые являются одним из главных факторов, ограничивающих его ускорение.

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