purifier. The bowl casing drain line directs drained
liquid into the sump tank. A short length of rubber
hose is installed in this line to perform the same
function as the flexible pipe connection in the water-
Drive Housing and Assemblies
The drive housing bolts to and supports the bowl
casing, cover, and bowl shell assembly. The drive
housing contains the spindle assembly, direct drive
assembly, speed counter, brake, and lubrication
The spindle assembly (fig. 4-29) is the vertical
drive shaft for the bowl shell assembly. Three sets of
ball bearings support the spindle assembly; a set at
the top, a set at the center, and a set at the bottom.
All three sets of ball bearings are lubricated by oil.
Located between the upper and lower bearings of the
center set of ball bearings is a large vertical spring.
This spring acts as a shock absorber to absorb any
vertical thrust of the spindles shaft when the purifier
is started. Six equally spaced horizontal springs
surround the upper set of ball bearings. These
springs absorb and cushion any horizontal movement
of the bowl shell assembly and thus reduce vibration.
The lower end of the spindles shaft is geared to the
horizontal drive shaft of the direct drive assembly.
The direct drive assembly transmits drive motor
power to the spindle, which, in turn, transmits power
to the bowl shell assembly. The direct drive assembly
(fig. 4-30) connects the purifier to the motor shaft by
a flexible coupling. The coupling consists of two
coupling halves, with the motor end fitted to the
motor shaft and the purifier end fastened to the
brake drum with four bolts. Each coupling half has
protruding studs (which are offset of each other) that
engage a rubber cushion installed between the two
The drive motor shaft turns the coupling, which
turns horizontal drive shaft. The horizontal drive
shaft is supported by two ball bearings; an outer and
an inner bearing. The outer and inner shaft bearings
are lubricated by oil. A worm wheel gear is keyed to
the drive shaft. This gear engages the gear at the
base of the spindle assembly. A smaller gear, which is
part of the worm wheel gear, is used to drive a speed
The speed counter (fig. 4-31) is used to determine
the rpm of the bowl shell assembly. Basically, it
consists of a shaft that penetrates the drive housing.
One end is
Figure 4-30.Direct drive assembly.
Figure 4-31.Speed counter.