Compressor Discharge System, Functional Description; Control System, Functional Description- Standard Electro-Mechanical - Sullair LS-100L Operator's Manual

A portion of the fluid flowing to the compressor is
routed to the anti-friction bearings which support the
rotors inside the compressor unit. Prior to entering
the compressor unit, this fluid is taken through the
fluid filter, thus assuring properly filtered lubricant
for bearing supply.
The fluid filter has a replacement element and an
integral pressure bypass valve. A gauge on the
instrument panel shows red when the filter needs
servicing. This gauge has a pressure setting lower
than that of the bypass valve. The gauge should be
checked with compressor running at full system
pressure.
Water-cooled versions of the compressor have a
water-flow regulating valve, which operates to con-
serve water during periods of varying load on the
compressor and maintains discharge temperature.
In addition, water-cooled models have a water pres-
sure switch to prevent operation with inadequate
water pressure.
2.5 COMPRESSOR DISCHARGE SYSTEM, FUNC-
TIONAL DESCRIPTION
Refer to Figures 2-3A
unit discharges the compressed air/fluid mixture
into the combination receiver/sump.
The receiver has three basic functions:
1. It acts as a primary fluid separator.
2. Serves as the compressor fluid sump.
3. Houses the final fluid separator.
The compressed air/fluid mixture enters the receiv-
er and is directed against the internal baffle.
direction of movement is changed and its velocity
significantly reduced, thus causing large droplets of
fluid to form and fall to the bottom of the
receiver/sump. The fractional percentage of fluid
remaining in the compressed air collects on the sur-
face of the separator element as the compressed
air flows through the separator. A return line (or
scavenge tube) leads from the bottom of the sepa-
rator element to the inlet region of the compressor
unit. Fluid collecting on the bottom of the separator
is returned to the compressor by a pressure differ-
ential between the receiver and the compressor
inlet. A visual sight glass is located on the return line
to observe this fluid flow. There is also an orifice in
this return line (protected by a strainer) to assure
proper flow. This separation will reduce the fluid
carry-over to less than 2 ppm (parts per million). A
gauge, located on the instrument panel, shows red
if abnormal pressure drop through the separator
develops. At this time, separator element replace-
and 2-3B. The compressor
ment is necessary. This gauge must be checked
with the compressor running fully loaded.
A minimum pressure/check valve, located down-
stream from the separator, assures a minimum
receiver pressure of 50 psig (3.4 bar) during loaded
conditions. This pressure is necessary for proper
air/fluid separation and proper fluid circulation.
A terminal check valve is incorporated into the min-
imum pressure/check valve to prevent compressed
air in the service line from bleeding back into the
receiver on shutdown and during operation of the
compressor in an unloaded condition.
A pressure relief valve (located on the wet side of
the separator) is set to open if the sump pressure
exceeds the sump tank rating. A temperature switch
will shut down the compressor if the discharge tem-
perature reaches 235ºF (113ºC).
DO NOT remove caps, plugs, and/or other compo-
nents when compressor is running or pressurized.
Stop compressor and relieve all internal pressure
before doing so.
Fluid is added to the sump via a capped fluid filler
opening, placed low on the tank to prevent overfill-
ing of the sump. A sight glass enables the operator
to visually monitor the sump fluid level.
2.6 CONTROL SYSTEM, FUNCTIONAL DESCRIP-
TION- STANDARD ELECTRO-MECHANICAL
Refer to Figure 2-4. The purpose of the compressor
Control System is to regulate the compressor air
The
intake to match the amount of compressed air being
used. At approximately 10 psig (0.7 bar) air line
over-pressure, the control system will automatically
blow down the compressor and greatly reduce the
unload power consumption. The Control System
consists of an inlet valve, (located on the compres-
sor air inlet), blowdown valve, solenoid valve,
pressure switch, and a pressure regulator. The
functional descriptions of the Control System are
given below in four distinct phases of compressor
operation. The following guidelines apply to all LS-
100 Series compressors. For explanatory purpos-
es this description will apply to a compressor with
an operating pressure range of 125 to 135 psig (8.6
to 9.3 bar). A compressor with any other pressure
range would operate in the same manner excepting
stated pressures.
When the line pressure drops to the low setting (cut-
in pressure; usually 100 psig [6.9 bar] on low pres-
sure ["L"] compressors and 125 psig [8.6 bar] on
high pressure ["H"] compressors, 150 psig [10.3
Section 2
DESCRIPTION
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