P r e s s u r e (psig)
Air motors, crane drives, and
7 0 - 125
s t a r t i n g motors for, internal
Laundries and dry cleaning
75 - 100
Starting aircraft jet engines 1
Instrumentation and control
40 - 90
G e n e r a l service (tools, cleaning,
Sootblowing for HTW generators
and steam boilers
Medium-pressure compressed air may also be used for this purpose.
3.2 Medium-Pressure Compressed Air Systems. These systems provide compressed
air within the range of 126 to 399 psig. Such systems are not extensive and
a r e generally provided with individual compressors located near the load.
T y p i c a l applications for medium-pressure applications follow.
100 - 399
S t a r t i n g diesel engines
145 - 175
Retread tire molds
175 - 200
3.3 High-Pressure Compressed Air Systems. These systems provide compressed
air within the range of 400 to 6,000 psig. To minimize the hazards that exist
w i t h higher pressures and capacities, separate compressors are used for each
required pressure. However, for systems at 3,000 psig that also require
r e l a t i v e l y small amounts of air at a lower pressure, but above 400 psig, air
may be supplied in the higher value for the main system and reduced to the
l o w e r pressure for small branches provided that safety relief valves are
used. E x a m p l e s of high-pressure applications follow.
600 and 3,000
100, 750, 1,500 and 4,500
T e s t i n g laboratories
4 AIR RECEIVERS. A i r receivers are tanks installed in the compressor plant
t h a t serve as reservoirs for the storage of compressed air. Air receivers
permit meeting peak demands in excess of compressor capacity and act as
p u l s a t i o n dampeners on reciprocating compressor installations. They also
s e p a r a t e , collect, a n d drain moisture, oil, and dirt from the system air.
F i g u r e 5-1 shows a typical air receiver.
4.1 Secondary Air Receivers. L o n g distribution lines that are marginally
sized may occasionally require secondary receivers located near a point of
heavy demand. Where peak demands are of relatively short duration, this
additional storage capacity located near the consumer avoids excessive
pressure drops in the line.