BENDIX TU-FLO 400-500-1000 AIR COMPRESSOR Manual page 2

DESCRIPTION AND OPERATION
GENERAL
The function of the air compressor is to build up and maintain
the air pressure required to operate air powered devices in
air brake or air auxiliary systems.
DESCRIPTION
Tu-Flo ® Type 400, 500, and 1000 compressors are single
stage, reciprocating piston type compressors. Tu-Flo
(Fig. 1) and 500 (Fig. 2) compressors have two cylinders
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while the Tu-Flo 1000 compressor (Fig. 3) is a V-type
design having four cylinders. The rated capacity of all Bendix
compressors is their piston displacement in cubic feet per
minute when operating at 1,250 RPM. The rated capacity
of the Tu-Flo ® 400 compressor is 7-1/4 cubic feet per minute.
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The Tu-Flo 500 compressor is rated at 12 cubic feet per
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minute and the Tu-Flo 1000 compressor has a rating of 24
cubic feet per minute.
Tu-Flo ® type compressors have automatic type inlet valves.
Their unloading mechanisms are located in the cylinder block
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FIGURE 1 - TU-FLO 400 AIR COMPRESSOR
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FIGURE 2 - TU-FLO 500 AIR COMPRESSOR
FIGURE 3 - TU-FLO ® 1000 AIR COMPRESSOR
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and they have no external moving parts. Both air and water
cooled type compressors are available. Various mounting
and drive adaptations are used as required by different vehicle
engine designs (Fig. 4).
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400
FIGURE 4 - VARIOUS COMPRESSOR MOUNTINGS
Compressors are either engine or self-lubricated. The
majority used are the engine lubricated types (Fig. 5) which
obtain the oil necessary to lubricate their moving parts from
the engines on which they are mounted. To meet the
requirements of some manufacturers and for field
installations, self-lubricated types (Fig. 6) are available. They
are compressors having a self-contained oil supply and
pumping system.
The method of lubricating the moving parts of the compressor
is the same in either type. Oil is forced through the oil
passage in the crankshaft and out around each connecting
rod journal. The turning motion of the crankshaft throws the
oil that is forced out at the journals, against the cylinder
bores and crankcase walls, lubricating the bores and
crankshaft bearings.
The wrist pins and wrist pin bushings are lubricated in two
ways depending upon the type connecting rods used. Older
design compressors had forged steel rifle-drilled rods through
which oil was forced to the wrist pin bushings. Later versions