Figure 1 Figure 2
10.2 Reciprocating Compressor
A Reciprocating compressor uses a moving piston in an enclosed cylinder. In a
single-acting design, compression takes place on just one side of the piston and
produces air on only one stroke per revolution. Double-acting compressors develop
compression on both sides of the piston and produce air on two strokes per crank
shaft revolution. This results in almost twice the capacity of a single-acting design
of identical bore and stroke. In either case, the compressor might be air or water-
cooled, lubricated/non-lubricated.
Single-stage reciprocating compressors have one or more cylinders connected in
parallel to compress air from atmospheric pressure to the final discharge pressure
in one step. Reciprocating air compressors cover a broad range of output capacity.
They are typically found in applications from 1 horsepower to more than 600 horse
power. The practical limit for a single stage of reciprocating compressors is typically
considered to be 5 to 6 ratios. That is, if intake air is considered to be about 1 bar
the discharge limit from a single stage is about 6 bar. To achieve higher discharge
pressures the process is simply repeated in a second compressor piped in series with
the first to achieve two-stages of compression. This is termed as double stage
com pressor.Fig.2 shows the two stage double acting reciprocating compressor.