Section 1
DESCRIPTION
6
Figure 1-5 Compressor Air Inlet System
being used, the service line pressure will rise above
100 PSI. The pressure regulator valve gradually
opens, applying air pressure to the diaphragm
chamber of the Sullicon control which partially
closes the butterfly valve on the compressor air in-
let; reducing the amount of air entering the com-
pressor until it matches the amount of air being
used. The control system functions continually in
this manner, between the limits of 100- 110 PSI, in
response to varying demands from the service line.
The pressure regulator has an orifice which vents a
small amount of air to the atmosphere when the
pressure regulator controls the butterfly valve. The
orifice also bleeds any accumulated moisture from
the Sullicon control. A 1/4” check valve prevents
the regulator signal from opening the pneumatic
blowdown valve.
UNLOAD -IN EXCESS OF 110 PSI LINE PRES-
SURE
When no air is being used, the service line pressure
rises to the setting (cut-out pressure) of the pres-
sure switch. The pressure switch opens, interrupt-
ing the electrical power to the solenoid type pilot
valve. At this time, the pilot valve allows dry sump
tank air pressure to be applied directly to the con-
trol diaphragm, keeping the butterfly valve closed.
Simultaneously, the pilot valve sends a pneumatic
signal to the blow down valve. The blowdown valve
opens the sump to the atmosphere, reducing the
sump pressure to approximately 40 -55 PSI. The
check valve in the air service line prevents line pres-
sure from returning to the sump.
Whenthelinepressuredropstothelowsetting
(cut-in pressure) of the pressure sw itch (usually
100 PSI on low pressure machines and 115 PSI on
high pressure machines), the pressure switch
closes, re-energizing the three-way pilot valve and
allowing the blowdown valve to close. The re-ener-
gized pilot valve also prevents line pressure from
reaching the Sullicon control. Should the pressure
begin t o rise, the pressure regulator will resume its
normal function as previously described.
F or a machine with varied periods of time when
there are no air requirements, a ”Dual-Control” op-
tion is available. This option allows you to set the
machineinanautomaticpositionwherebythema-
chine will shut down when no compressed air re-
quirement is present and restart as compressed air
is needed.
1.7 AIR INLET SYSTEM, FUNCTIONAL DE-
SCRIPTION
Refer to Figure 1-5. The compressor inlet system
consists of a dry-type air filter, a restriction gauge
and an air inlet valve.
The restriction gauge, located on the compressor
instrument panel, indicates the condition of the air
filter by showing red when filter maintenance is re-
quired.
The butterfly-type air inlet valve directly controls the
amount of air intake to the compressor in response
to the operation of the Sullicon control (par. 1.6).
1.8 INSTRUMENT PANEL GROUP. FUNCTIONAL DE-
SCRIPTION
Refer to Figure 1-6 for specific location of parts de-
scribed. The instrument panel group consists of a
panel containing the line pressure and sump pres-
sure gauges, the discharge temperature gauge,
the air filter restriction gauge, and the maintenance
Figure 1-6 Instrument Panel Group
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