System Dynamics; Description & Application; Principles Of Compression Cycles - Quincy Compressor QR-25 Series Instruction Manual

SECTION 2 SECTION 2
SECTION 2 SECTION 2 SECTION 2
Fig. 2-1 Cross Section of Typical QR-25
2 Stage Pressure Lubricated Cylinder & Crankcase
QR-25 Series
52201-105, May 2003
der. The air is then compressed in the cylinder during the upstroke of the
piston. Total compression, from atmospheric pressure to the final discharge
pressure, is accomplished in one stroke of the piston.
Two Stage Compressors
During the downstroke of the piston of a two stage compressor, air is drawn
through an intake valve in the head of the compressor into the low pressure
cylinder and compressed during the upstroke of the piston.
The compressed air is then released through a discharge valve in the head
of the compressor to an intercooler (usually finned tubing) where the heat
resulting from compression is allowed to dissipate. The cooler compressed air
is then drawn into a second compression cylinder, the high pressure cylinder,
for compression to final pressure.
From there the compressed air is released through a discharge valve to an
air receiver tank or directly to a network of compressed air supply lines. In one
revolution of the crankshaft a compression cycle is completed.
4

SYSTEM DYNAMICS

SYSTEM DYNAMICS
SYSTEM DYNAMICS SYSTEM DYNAMICS SYSTEM DYNAMICS
Description & Applica-
tion
The Quincy Compressor QR-25
Series consists of heavy duty
industrial, belt driven, single or
two stage compressors. Single
stage compressors are capable of
delivering up to 100 PSIG con-
tinuously.
compressors are capable of de-
livering up to 150 PSIG
intermittantly (with proper con-
trols and modifications). Two
stage compressors can deliver
up to 200 PSIG continuously,
and up to 250, 350 or 500 PSIG
intermittently depending upon
the model, controls and configu-
ration.
Principles of Compres-
sion Cycles
Single Stage Compressors
During the downstroke of a single
stage compressor, air is drawn
through an intake valve in the
head of the compressor and into
Pix 1064
the cylinder. At the bottom of
the stroke, the intake valve closes
and air is trapped in the cylin-
3501 Wismann Lane, Quincy IL - 62305-3116
Some single stage
Quincy Compressor