Sullair LS20 Operator's Manual And Parts List page 14

Section 2
DESCRIPTION
Figure 2-4 Compressor Fluid Cooling/Lubrication and Discharge System- Water-cooled
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 fluid temperature is below 175ºF (79ºC).
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 175ºF
(79ºC), due to the heat of compression, the thermal
8
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 then on to the compres-
sor unit.
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 enter-
ing the compressor unit, this fluid is taken through
the fluid filter, thus assuring properly filtered lubri-
cant for bearing supply.
The fluid filter has a replacement element and an
integral pressure bypass valve. An indicator on the
instrument panel shows when the filter needs serv-