Technical Terms of Reciprocating Air Compressors

Technical Terms of Reciprocating Air Compressors Points : Technical Terms of Reciprocating Air Compressors, Inlet Pressure, Discharge Pressure, Compressor ratio (or pressure ratio), Compressor Capacity, Free Air Delivery, Swept volume, Mean Effective Pressure The following technical terms, which will be frequently used in this site, should be clearly understood at this stage: 1. Inlet Pressure It is the absolute pressure of air at the inlet of a compressor. 2. Discharge Pressure It is the absolute pressure of air at the outlet of a compressor. 3. Compressor ratio (or pressure ratio) It is the ratio of discharge pressure to the inlet pressure. Since the discharge pressure is always more than the inlet pressure, therefore the value of compression ratio is more than unity. 4. Compressor Capacity It is the volume of air delivered by the compressor, and is expressed in m³/minor m³/sec. 5. Free Air Delivery It is the actual volume delivered by a compressor when reduced to the normal temperature and pressure condition. The capacity of a compressor is generally given in terms of free delivery. 6. Swept volume It is the volume of the air sucked by the compressor during its suction stroke: Mathematically, the swept volume or displacement of a single acting air compressor is equal to fR2l (Where “R” is the radius of cylinder bore and “1” the piston stroke). 7. Mean Effective Pressure As a matter of fact, air pressure on the compressor piston keeps on changing with the movement of piston in the cylinder. The mean effective pressure of the compressor is found out mathematically by dividing the work done per cycle with the stroke volume.