Air Inlet System, Functional Description; Instrument Panel Group, Functional Description - Sullair LS-12 Operators Manual And Parts Lists

Figure 2 ---5B Control System, Sequence of Operation (Typical)
SOLENOID
UNLOAD --- IN EXCESS OF 110 PSIG (7.6 BAR)
LINE PRESSURE
When no air is being used, the service line pres-
sures rises to the setting (cut---out pressure) of the
pressure switch. The pressure switch opens, inter-
rupting the electrical power to the solenoid valve. At
this time, the solenoid valve allows dry sump tank
air pressure to be applied directly to the control dia-
phragm, keeping the butterfly valve closed. Simul-
taneously, the solenoid valve sends a pneumatic
signal to the blowdown valve. The blowdown valve
opens the sump to the atmosphere, reducing the
sump pressure to approximately 40 to 50 psig (2.8
to 3.8 bar). The check valve in the air service line
prevents line pressure from returning to the sump.
When the line pressure drops to the low setting
(cut---in pressure) of the pressure switch (usually
100 psig [6.9 bar] on low pressure compressors
and 115 psig [7.9 bar] on high pressure compres-
sors), the pressure switch closes, re---energizing
the three---way solenoid valve and allowing the
blowdown valve to close. The re---energized sole-
noid valve again prevents line pressure from reach-
ing the Sullicon Control. Should the pressure begin
to rise, the pressure regulator will resume its nor-
mal function as previously described.
For a compressor 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
compressor in an automatic position whereby the
compressor will shut down when no compressed
air requirement is present and restart as com-
pressed air is needed.
2.7 AIR INLET SYSTEM,
SCRIPTION
R e f e r t o F i g u r e 2 --- 6
tem consists of a dry ---type air filter, a restriction
gauge and a control 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 re-
sponse to the operation of the Sullicon Control (see
S ec tion 2 . 6 , Contr ol S y
See Section 6 for Air Filter Maintenance Proce-
dures.
2.8 INSTRUMENT PANEL GROUP, FUNCTIONAL
DESCRIPTION
Ref er to Figur e 2 --- 7 f or spec if ic l oc a tion of par ts de -
scribed. The instrument panel group consists of a
panel containing the line pressure, sump pres-
sure and discharge temperature gauges, the air
filter, the separator element and the fluid filter,
Section 2
DESCRIPTION
FUNCTIONAL
. T h e c om p r essor i n l et sy s -
stem).
DE-
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