as it varies engine speed and air intake opening to meet
the demand for compressed air.
Because of the great variety of throttle control and
pressure-regulating devices used with compressors,
detailed instructions on their adjustment and
maintenance should be obtained from the
manufacturers maintenance and repair manual. When
a control valve fails to work properly, disassembly and
a thorough cleaning are necessary. Some control valves
are fitted with filters filled with sponge or woolen yarn
to prevent dust and grit from entering into the valve
chamber and to remove gummy deposits that come from
the oil used in the compressor cylinders. Replace the
filter with the specified material each time a valve is
Do NOT use cotton as a filter element as it will
pack down and stop the airflow.
AIR INTAKE SYSTEM
Air compressors are protected against ingestion of
dust and foreign particals by air cleaners. These maybe
oil bath or dry-filter type. The filtration system maybe
a single falter serving both the power source and the air
compressor, or each unit may have an individual filter.
Larger air compressors working in dirty conditions may
use a two-stage system (fig. 8-11). In most cases, the
falters are the same as those used on automotive and
construction equipment engines, just larger.
Satisfactory operation of the compressor depends
on a clean supply of air. Unless the filters are inspected
and cleaned regularly they become clogged, lose their
efficiency, become damaged, and compressor capacity
is lost. Air filters can be replaced or cleaned. Oil bath air
falter cleaning instructions can be found in the relevant
maintenance and repair manual. This type of air filter is
no longer common. The dry-type filter can be replaced
or cleaned. Before cleaning, check the filter for damage
Figure 8-11.Two-stage, oil bath, air filter system.