Sullair 900 - 2.3 Sullair Compressor Unit Functional Description; 2.4 Compressor Cooling and Lubrication System

2: Description 600H, 750, 750H, 750HH, 825, 900, 900H, 1050 T3 CAT User Manual
02250197-981 R01
20 Subject to EAR, ECCN EAR99 and related export control restrictions.
2.3 Sullair compressor unit,
functional description
Sullair compressors feature the Sullair compressor unit, a
single-stage, positive displacement, flood lubricated-type
compressor. This unit provides continuous compression
to meet your needs.
Sullair compressors are factory-filled with Sullair AWF
®
lubricant. For more information on fluid fill, refer to Sec-
tion 3.5: Application guide on pa
ge 42.
Fluid is injected into the compressor unit hoses and
mixes dire
ctly with the air as the rotors turn, compressing
the air. The fluid flow has three basic functions:
• As coolant, it controls the rise of air tempera-
ture norm
ally associated with the heat of com-
pression.
• Seals the clearance paths between the rotors
and the stator and also between the rotors
themselves.
• Acts as a lubricating film between the rotors
allowing one rotor to directly drive the other,
which is an idler.
After the air/fluid mixture is discharged from the compres-
sor unit, the fluid is separated from the air. At this time,
the
ai
r flows through an aftercooler and separator then to
your service line while the fluid is being cooled in prepa-
ration for reinjection.
2.4 Compressor cooling and
lubrication system, functional
description
Refer to Figure 2-2 and Figure 2-3. The compressor cool-
ing and lubrication system is designed to provide ade-
quate lubrication as well as maintain the proper operating
temperature o
f the compressor. In addition to the cooler
and fan, the system consists of a main filter and thermal
valve.
Fluid is used in the system as a coolant and a lubricant.
The fluid is
housed in the receiver tank.
Upon start up, the fluid temperature is cool, and routing
to the cooler is not required. The fluid first enters the ther-
m
al valve and then flows on to the compressor unit,
bypassing the
cooler. As the compressor continues to
operate, the temperature of the fluid rises and the ther-
mal valve element begins to shift. This for
ces
a portion of
the fluid to the fluid cooler. The cooler is a radiator-type
that works in conjunction with the engine fan. The fan
draws air through the cooler removing the heat of com-
pression from the fluid. From the cooler, the fluid is
routed back to
the thermal va
lve.
Before the temperature of the fluid reaches the valve set
point, cool
ed fluid is mixed with warmer fluid. When the
temperature of the fluid reaches 170°F (77°C), the ther-
mal element shifts completely causing all fluid to flow to
the coo
ler.
The thermal valve incorporates a pressure
relief valve, which allows fluid to bypass the cooler, if the
cooler becomes plugged or frozen. This helps assure
that fluid will continue to be provided to the compressor
for lubrication. After the fluid passes through the thermal
valve it is then directed through the main fluid filter.
There, the fluid is filtered in preparation for injection into
the compression chamber and bearings of the compres-
sor unit. The filter has a rep
laceable elem
ent and a built-
in bypass valve which allows the fluid to flow even when
the filter element becomes plugged and requires chang-
ing or when the viscosity of the fluid is too high for ade-
quate flow. After the fluid is properly filtered, it then flows
on
to
the compressor unit where it lubricates, seals and
cools the compression chamber as well as lubricates the
bearings and gears.
NOTE
With a Sullair compressor, there is no mainte-
nance or inspection of the internal parts of the
compressor unit permitted in accordance with
the terms of the warranty.