Compressor Cooling And Lubrication System, Functional Description - Sullair LS20T Operator's Manual And Parts List

Section 2
DESCRIPTION
Figure 2-1B Sullair Series LS20T Rotary Screw Compressor- Water-cooled (Typical)
or inspection of the internal parts of the compressor
unit permitted in accordance with the terms of the
warranty.
Fluid is injected into the compressor unit at each
stage, and mixes directly with the air as the rotors
turn, compressing the air. The fluid flow has three
main functions:
• As coolant, it controls the rise of air temper-
ature normally associated with the heat of
compression.
• Seals the leakage 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
compressor unit, the fluid is separated from the air.
At this time, the air flows to the service line and the
fluid is cooled in preparation for reinjection.
2.4 COMPRESSOR COOLING AND LUBRICATION
SYSTEM, FUNCTIONAL DESCRIPTION
Refer to Figures 2-2,
6
2-3A and 2-3B. The Cooling
and Lubrication System consists of a fluid cool-
er, aftercooler, full flow fluid filters, fluid stop
valve, thermal valve and interconnection piping.
For water-cooled models, a shell and tube fluid
cooler and aftercooler are mounted on the com-
pressor package. For air-cooled models, they are
radiator-type coolers, and are mounted on the com-
pressor package.
The pressure in the receiver/sump causes fluid flow
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
when the discharge temperature is below 220ºF
(104.4ºC). The fluid passes through the thermal
valve, the main fluid filter and directly to the com-
pressor unit, thus feeding the bearings, seals and
rotor area.
As the discharge temperature rises above 220ºF
(104.4ºC), due to the heat of compression, the ther-
mal valve begins to close and a portion of the fluid
then flows through the cooler. From the cooler, the