Compressor Discharge System, Functional Description; Control System, Functional Description - Sullair LS-200S Operator's Manual And Parts List

Section 2
DESCRIPTION
by forcing the fluid from the high pressure area of
the sump to an area of lower pressure in the com-
pressor unit.
Fluid flows from the bottom of the receiver/sump to
the thermal valve. The thermal valve is fully open to
the compressor unit when the fluid temperature is
below 180ºF (82ºC). The fluid passes through the
thermal valve, the main filter and directly to the
compressor unit where it lubricates, cools and seals
the rotors and the compression chamber.
As the discharge temperature rises above 180ºF
(82ºC), due to the heat of compression, the thermal
valve begins to close and a portion of the fluid then
flows through the cooler. From the cooler, the fluid
flows to the main filter and on to the compressor
unit.
The filter has a replacement element and an inte-
gral pressure bypass valve. When the element
pressure drop exceeds 20 psid (1.4 bar), an internal
switch contact opens and the Supervisor module
displays a maintenance requirement message.
Water-cooled models have a water pressure switch
to prevent operation with inadequate water pres-
sure.
2.5 COMPRESSOR DISCHARGE SYSTEM, FUNC-
TIONAL DESCRIPTION
Refer to Figures 2-2
discharges the compressed air/fluid mixture into the
combination receiver/sump. The receiver has three
functions:
• It acts as a primary fluid separator.
• Serves as the compressor fluid sump.
• Houses the final fluid separator elements.
The compressed air/fluid mixture enters the receiv-
er and is directed through a centrifugal baffle.
Through centrifugal action and a velocity reduction
large droplets of fluid form and fall to the bottom of
the receiver/sump. The fractional percentage of
fluid remaining in the compressed air collects on the
surface of the dual separator elements as the com-
pressed air flows through them. Two return lines (or
scavenge tubes) lead from the bottom of each sep-
arator element to the low pressure region of the
compressor unit. Fluid collecting on the bottom of
each separator is returned to the compressor by a
pressure difference between the receiver and the
compressor inlet. Sight glasses are located in the
return lines to observe this fluid flow. There are also
orifices (protected by strainers) within the sight
glasses to assure proper flow. When the total pres-
sure drop across the elements exceeds 10 psid (0.7
8
and 2-4. The compressor unit
bar), the Supervisor displays a maintenance
requirement message.
The receiver is a pressure vessel designed and
built to codes administered by appropriate govern-
ing bodies. A combination minimum pressure/check
valve, located downstream from the separator,
assures a minimum receiver pressure of 50 psig
(3.5 bar) during all conditions. This pressure is nec-
essary for proper air/fluid separation and proper
fluid circulation while supplying air to the system.
This valve also acts as a check valve preventing
compressed air in the service line from bleeding
back into the receiver on shutdown and during
operation on the compressor in an unloaded condi-
tion.
A pressure relief valve (located on the wet side of
the separator) is set to open if the sump pressure
exceeds 210 psi (14.5 bar). For added safety the
Supervisor is programmed to shutdown the pack-
age when:
a) A pressure level, above unload setting but below
relief valve setting, is reached.
b) A temperature level exceeding 235ºF (113ºC) is
reached.
See Supervisor functional description for further
details on shutdown pressure levels.
LS-200S models are equipped with a high pressure
shutdown protection to shut down the compressor
at 20 psig (1.4 bar) above rated pressure. This pre-
vents the pressure relief valve from opening under
routine conditions, thereby preventing fluid loss
through the pressure relief valve. A temperature
switch will shut down the compressor if the dis-
charge temperature reaches 235ºF (113ºC).
DO NOT remove caps, plugs, and/or other com-
ponents when compressor is running or pressur-
ized.
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- SUPERVISOR CONTROLLER™
Refer to Figures 2-5A, 2-5B, 2-5C,
The purpose of the compressor Control System is
to regulate the amount of air being compressed to
2-5D and 2-5E.