17. Study the key words to the crossword from Unit III.

18. Engineer tested. Do you believe …

1) that compressed air generated from rotary screw compressors and proper clean air treatment is up to 10,000 times cleaner than the air we breathe?

2) that air volume increases (expands) as temperature increases?

3) that compressed air is the fourth utility in an industrial plant, after electricity, gas and water?

19. Study the compressor refrigerator schematic, operation and construction. Discuss the information in dialogues. How do you see the compressor refrigerator in the future?

Evaporator – испаритель, motor – двигатель/мотор, condenser (cooler) – конденсатор, compressor – компрессор, cooling fin- охлаждающее ребро

The most common refrigeration unit is the compressor type.

• A compressor, which is found at the base of the fridge, contains a gas refrigerant. A refrigerant is a liquid that can evaporate at very low temperatures. 'Freon 12' and liquid ammonia are examples of refrigerants that have been used in refrigerators. A small motor attached to the compressor forces the gaseous refrigerant into the condenser.

• The condenser cools and condenses the gas refrigerant back into a liquid. A condenser is visible on the outside of the back of a refrigerator, attached to which are a number of cooling fms, which help to cool the refrigerant by conducting heat away from the condenser.

• The refrigerant, which is now in a liquid state, passes into the evaporator, the coldest part of the fridge. Here the refrigerant evaporates by drawing heat from the fridge cabinet. In this way, the cabinet is cooled.

• The gaseous refrigerant is then pumped back to the compressor, where the cycle will begin again.

• A thermostat is fitted, which disconnects the electricity when the cabinet is cool enough and restarts the motor when temperatures rise.

Construction

1. The outer casing of a refrigerator is made from enamelled steel (сталь, покрытая эмалью). A variety of colors and finishes are available such as matt, gloss, textured and even wood grain.

2. The interior of the fridge is generally made from moulded polystyrene.

3. Sandwiched between the outer casing of steel and the inner plastic casing is a layer of insulating material.

4. The door of the fridge is fitted with a rubber gasket and a magnetic fastening to ensure that the low temperatures inside are maintained. Most models can have the door hinging to the right or the left. A light is automatically turned on when the door is opened.

5. The fridge cabinet houses a number of adjustable plastic-coated shelves and there are one or two clear or smoked-plastic drawers located at the base of the fridge.

6. Standard refrigerators have an icebox at the top of the fridge that is enclosed by a plastic hinged door.

7. A thermostat controls the temperature within the cabinet. Manufacturers usually indicate a normal setting that may need slight adjustment in very hot weather.

8. The door offers a range of moulded-plastic storage areas for butter, eggs and other dairy products.