Page 115 - Air and Gas Drilling Manual

Chapter
Four

Compressors

There are a variety of air and gas compressor designs in use throughout industry.
These designs vary greatly in the volume amounts of air or gas moved and the
pressures attained. The largest usage of compressors is in the oil and gas production
and transportation industries, and in the chemical industry. The information
regarding this technology will be used to develop an understanding of how
compressors can be used in air and gas drilling operations.
Air or gas compressors are very similar in basic design and operation to liquid
pumps. The basic difference is that compressors are movers of compressible fluids;
pumps are movers of incompressible fluids (i.e., liquids).

4.1 Compressor Classification
Similar to the classification of pumps, compressors are grouped in one of two
general classes: continuous flow (i.e., dynamic) compressors, and intermittent flow
(i.e., positive displacement) compressors (see Figure 4-1) [1, 2]. Intermittent flow
or positive displacement compressors move the compressible fluid through the
compressor in separate volume packages of compressed fluid (these volume packages
are separated by moving internal structures in the machine). The most important
subclass examples of positive displacement compressors are reciprocating and rotary
compressors. Continuous flow or dynamic compressors utilize the kinetic energy of
the continuously moving compressible fluid in combination with the internal
geometry of the compressor to compress the fluid as it moves through the device.
The most important subclass examples of dynamic compressors are centrifugal and
axial-flow compressors.

4-1
Copyright 2001 by The McGraw-Hill Companies, Inc. Click Here for Terms of Use.