Page 21 - Reciprocating Compressors Operation Maintenance
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8 Reciprocating Compressors: Operation and Maintenance
Compressors
Dynamic I Displacement
Ejector Radial Axial
Rotary Reciprocating
FIGURE 1 -5. Principal compressor types used in industry.
Positive displacement units are those in which successive volumes
of gas are confined within a closed space and elevated to a higher
pressure.
Rotary positive displacement compressors are machines in which
compression and displacement result from the positive action of
rotating elements.
Sliding vane compressors are rotary positive displacement
machines in which axial vanes slide radially in a rotor eccentrically
mounted in a cylindrical casing. Gas trapped between vanes is com-
pressed and displaced.
Liquid piston compressors are rotary positive displacement
machines in which water or other liquid is used as the piston to com-
press and displace the gas handled.
Two-impeller straight-lobe compressors are rotary positive dis-
placement machines in which two straight mating lobed impellers
trap gas and carry it from intake to discharge. There is no internal
compression.
Helical or spiral lobe compressors are rotary positive displacement
machines in which two intermeshing rotors, each with a helical form,
compress and displace the gas.