SECTION 2 TS20C USER MANUAL
17
2.3 COMPRESSOR COOLING
AND LUBRICATION
SYSTEM—FUNCTIONAL
DESCRIPTION
Refer to Figure 2-5. For air-cooled models, the
cooling and lubrication system consists of a fan, fan
motor, aftercooler/fluid cooler, full flow fluid filter,
thermal valve, and interconnecting tubes. For water-
cooled models, a shell and tube fluid cooler,
aftercooler and water-flow regulating valve are
substituted for the radiator-type cooler on air-cooled
compressors.
The pressure in the sump tank starts the fluid flow by
forcing the fluid from the high pressure area of the
tank to an area of lower pressure in the compressor.
Fluid flows from the sump tank to the thermal valve
that is fully open when the fluid temperature is below
170°F (77°C). The fluid passes through the thermal
valve, the main filter, and directly to the compressor
where it lubricates, cools and seals the rotors, and
the compression chamber.
As the discharge temperature rises above 170°F
(77°C), 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 fluid filter and on to the compressor. A
portion of the fluid flow to the compressor is routed to
the anti-friction bearings which support the
compressor rotors. Water-cooled versions of the
compressor that have an optional water-flow
regulating valve, it operates to conserve water during
periods of varying load on the compressor. The same
valve automatically shuts off the water supply when
the compressor is shut down. In addition, water-
cooled models have a water pressure switch to
prevent operation with inadequate water pressure.
The fluid filter has a replacement element and an
integral bypass valve. Refer to Section 6.6 on page
112.
2.4 COMPRESSOR DISCHARGE
SYSTEM—FUNCTIONAL
DESCRIPTION
Refer to Figure 2-5. The compressor discharges the
compressed air/fluid mixture into the combination
sump tank. The sump tank has three basic functions:
1. It acts as an air/fluid separator.
2. Serves as the compressor fluid sump.
3. Houses the air/fluid separator elements.
The compressed air/fluid mixture enters the sump
tank and flows through an internal baffle system that
changes the flow’s direction and velocity, which
causes most of the fluid to fall to the bottom of the
sump tank. A small amount of fluid remaining in the
compressed air collects on the surface of the
separator elements as the air flows through the
separators.
Two return lines (or scavenge tube) lead from the
bottom of the separators dry side to a medium
pressure region in the compressor. Scavenged fluid
is returned by a pressure differential between the
sump tank and compressor.
Visual sight glasses are located on the return line to
observe this flow. This return line also has an orifice
(protected by a strainer) to ensure an unobstructed
flow.
The Supervisor™ Controller will show an abnormal
pressure drop through the separator if the element
becomes dirty or plugged. (Refer to Section 6.8 on
page 114.) It will also shut down the compressor if
the discharge temperature reaches 235°F (113°C).
A minimum pressure/check valve located
downstream from the separator maintains the sump
tank pressure at approximately 50 psig (3.4 bar)
during load conditions. This pressure level is
necessary for proper air/fluid separation and
sufficient fluid circulation.
A terminal check valve is a sub-component of the
minimum pressure/check valve that prevents
compressed air in the service line from back-flowing
into the sump tank on shutdown or when the
compressor is operating in an unload condition. Also,
a pressure relief valve on the compressor’s wet side
opens if the sump tank pressure exceeds its rating.
Add fluid to the sump tank through the capped fluid
filter port. There is also a sight glass that enables the
user to check the sump tank fluid level. See Section
4.5: Fluid Level Check on page 105.
WARNING
Stop the compressor and relieve all internal
pressure before removing caps, plugs, and/
or other components when the compressor
is running or pressurized.
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