I. Read the following words, guess their meanings .

    stationary       commercial     gas turbine equivalent

 

compressor     extreme           final       diameter

 

electric            industrial        spiral     series

Reciprocating compressors use pistons driven by a crankshaft. They can be either stationary or portable, single or multi-staged, and are driven by electric motors or internal combustion engines. Reciprocating compressors are usually applied for continuous operation in commercial and industrial applications and may also be either stationary or portable.

Centrifugal compressors convert the velocity energy to pressure energy. They are used for continuous, heavy industrial uses and are usually stationary. Their application can be from 100 hp (75 kW) to thousands of horsepower. With multiple staging, they can achieve extremely high output pressures greater than 10,000 lb/in² (69 MPa). Many large snowmaking operations (like ski resorts) use this type of compressor. They are also used in internal combustion engines as superchargers and turbo-charges. Centrifugal compressors are used in small gas turbine engines or as the final compression stage of medium sized gas turbines.

Diagonal or mixed-flow compressor – are similar to a centrifugal compressor, The diagonal compressor has a lower diameter diffuser than the equivalent CF compressor.

Axial-flow compressor – use a series of fan-like rotating rotor to progressively compress the gas flow. Axial-flow compressors are normally used in high flow applications, such as medium to large gas turbine engines. They are almost always multi-staged.

The picture of the Axial-flow compressor .

Scroll compressor, also known as scroll pump uses two interleaved Archimedean spiral shaped scrolls to pump or compress fluids such as liquids and gases. These devices are known to be used for operating more smoothly, quietly, and reliably than conventional compressors. However, due to their smaller available free volume compared to reciprocating compressors, the reliability of scroll compressors is debatable. Many residential central heat pump and air conditioning systems and a few automotive air conditioning systems employ a scroll compressor instead of the rotary. The rotary compressor is a positive-displacement machine in which compression of the fluid is effected directly by a rotor and without the usual piston, connecting rod, and crank mechanism of the reciprocating compressor. Rotary compressors have advantages over other types of compressors by virtue of their high efficiency, small size and low cost. There are also reciprocating and wobble-plate compressors.

Diaphragm Compressor is used for hydrogen and compressed natural gas (CNG). Gas compressors are used in various applications where either higher pressures or lower volumes of gas are needed.

CNG Compressor has such system layout that makes the repair and maintenance convenient. It is important that no water is required for the compressor .

 

Notes: Centrifugal – центробежный, Diagonal or mixed-flow – диагональный , смешанный, Axial-flow – осевой, Scroll - спиральный , Diaphragm – диафрагменный , Archimedean – архимедова , c onventional – стандартный ; серийный , multi-staged – многоступенчатый, interleaved – перемежающийся, reciprocating – поршневой , wobble - plate – с качающейся шайбой , Rotary – ротационный , positive - displacement – нагнетательный , layout- компоновка , оборудование

 

Skim the text and answer the questions below.

1. What types of compressors can you name? 2. What are their main technical characteristics? 3. Where and what for are the compressors used? 4. Which compressors are used in internal combustion engines? 5. Could you decipher the abbreviation CNG?

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