CHARACTERISTIC DIMENSIONS :
Suction pressure – is the pressure measured at the compressor cylinder inlet flange.
Discharges pressure – is the total pressure measured at the discharge flange of the compressor
Compression ratio – is the ratio of the absolute discharge pressure to absolute suction pressure.
Top dead centre (TDC) - is the outer (at cylinder end) dead centre of the piston stroke
Bottom dead centre (BDC) – is the inner (crank side) dead centre of the piston stroke
Stroke – It is the distance traversed by the piston in moving between two dead centres (top and Bottom)
Suction volume – is the volume of gas that enters the compressor in each unit of time.
Piston displacement – is the volume of a gas displaced in a stroke
Volumetric efficiency – is the ratio of actual capacity of compressor to displacement (theoretical capacity)
Compression capacity – is ratio of the theoretical horsepower to indicated horsepower.
Mechanical efficiency – is the ratio of the indicated horsepower to the break horsepower delivered at the shaft.
Overall efficiency – is the product of compression efficiency and mechanical efficiency.
Compressor capacity - is expressed in ICFM (intake cubic feet per minute) or ACFM (actual cubic feet per minute) at intake conditions.
