Figure 10-35.—Path of contaminated oil through a disc-type purifier bowl (Delaval).
at the top to allow the fluid and water to discharge. The
bowl of the purifier is connected by a coupling unit to a
spindle. The spindle is suspended from a ball bearing
assembly. The bowl is belt-driven by an electric motor
mounted on the frame of the purifier.
The lower end of the bowl extends into a flexibly
mounted guide bushing. The assembly restrains
movement of the bottom of the bowl, but it also allows
the bowl enough movement to center itself during
operation. Inside the bowl is a device with three flat
plates that are equally spaced radially. This device is
commonly referred to as the THREE-WING DEVICE,
or just the three-wing. The three-wing rotates with the
bowl and forces the liquid in the bowl to rotate at the
same speed as the bowl. The liquid to be centrifuged is
fed, under pressure, into the bottom of the bowl through
the feed nozzle.
After priming the bowl with water, separation is
basically the same as it is in the disc-type purifier.
Centrifugal force causes clean fluid to assume the
innermost position (lowest specific gravity), and the
higher density water and dirt are forced outward towards
the sides of the bowl. Fluid and water are discharged
from separate openings at the top of the bowl. The
location of the fluid-water interface within the bowl is
determined by the size of a metal ring called a RING
DAM or by the setting of a discharge screw. The ring
dam or discharge screw is also located at the top of the
bowl. Any solid contamination separated from the liquid
remains inside the bowl all around the inner surface.
GENERAL NOTES ON PURIFIER
OPERATIONS
For maximum efficiency, you should operate
purifiers at the maximum designed speed and rated
capacity. Since reduction gear oils are usually
contaminated with water condensation, the purifier
bowls should be operated as separators and not as
clarifiers.
When a purifier is operated as a separator, you
should prime the bowl with fresh water before any oil
is admitted into the purifier. The water seals the bowl
and creates an initial equilibrium of liquid layers. If the
bowl is not primed, the oil is lost through the water
discharge port.
There are many factors that influence the time
required for purification and the output of a purifier,
such as the
1. viscosity of the oil,
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