Compressor Discharge System, Functional Description - Sullair LS-32 Operator's Manual And Parts List

fluid flow by forcing the fluid from the high pressure
area of the sump to an area of lower pressure in the
compressor unit. In case of low pressure
machines*.
Fluid flows from the receiver/sump to strainer, pump
and the thermal valve. The thermal valve bypass is
fully open to the compressor unit when the dis-
charge temperature is below 170°F (77°C) for all
compressors, except water-cooled 24KT models,
which is fully open up to 195°F (91°C). The fluid
passes through the thermal valve, the fluid stop
valve, the main fluid filter and directly to the com-
pressor unit.
As the discharge temperature rises above 170°F
(77°C) for all compressors (195°F [91°C] for water-
cooled 24KT models), due to the heat of compres-
sion, the thermal valve bypass begins to close and
a portion of the fluid then flows through the cooler.
From the cooler, the fluid flows to the fluid stop
valve, the main filter, and on to the compressor unit.
The fluid filter has a replacement element and an
integral pressure bypass valve.
The fluid stop valve prevents fluid from flooding the
compressor unit when the compressor is shut
down. When the compressor is operating, the fluid
stop valve is held open by air pressure from the
fluid pump allowing a free flow of fluid from the
receiver/sump back to the compressor unit. On
shutdown, the compressor unit pressure is reduced,
causing the fluid stop valve to close and isolate the
compressor unit from the cooling system.
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
through a discharge check valve into the combina-
tion receiver/sump. The discharge check valve pre-
vents air/fluid in the receiver from returning to the
compression chamber after the compressor has
been shut down. The receiver has three functions:
1. It acts as a primary fluid separator.
2. It serves as the compressor fluid sump.
3. It houses the final fluid/air separator elements.
The compressed air/fluid mixture enters the receiv-
er and is directed against an internal baffle. The
direction of movement is changed and its velocity
*An external pump is provided to assist the fluid flow.
and 2-4. The compressor unit
DESCRIPTION
significantly reduced, thus causing the large
droplets of fluid to fall to the bottom of the receiv-
er/sump. The fractional percentage of fluid remain-
ing in the compressed air collects on the surface of
the nested separator elements (primary and sec-
ondary) as the compressed air flows through them.
Two return lines (or scavenge tubes) lead from the
bottom of each separator element to the low pres-
sure inlet region of the compressor unit. Fluid col-
lecting on the bottom of each separator is returned
to the compressor due to the pressure difference
between the receiver and the compressor inlet.
Sight glasses are located in the return lines to
observe this fluid flow.
Controller microprocessor control monitors the
TM
condition of the separator elements by reading the
differential pressure on the digital display. At a dif-
ferential of 10 psig (0.7 bar), or greater, the opera-
tor will be told to service the separator elements. At
this time, separator element replacement is neces-
sary.
The receiver is an ASME pressure vessel. A combi-
nation minimum pressure/check valve, located
downstream from the separator, assures a mini-
mum receiver pressure of 40 psig (2.8 bar) during
full load operation. This pressure is necessary for
proper air/fluid separation and proper fluid circula-
tion 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 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 rated pressure of the tank.
All Sullair compressor models are equipped with
high pressure shutdown protection to shut down the
compressor at 20-35 psi above rated pressure. This
prevents the pressure relief valve from opening
under normal conditions, thereby preventing fluid
loss through the pressure relief valve. The
Supervisor Controller will shut down the compres-
sor if the discharge temperature reaches 235°F
(113°C).
DO NOT remove caps, plugs, and/or other com-
ponents when compressor is running or pres-
surized.
Stop compressor and relieve all internal pressure
Section 2
dP1 on the Supervisor
7