(last-chance filters) for straining the oil just before
There are several types of filters used for
it passes through the spray nozzles onto the bear-
filtering the lubricating oil. The filtering elements
come in a variety of configurations. The parts of
a main oil filter-include a-housing, which has an
internal relief valve and a filtering element.
The magnetic-chip detector is a metal plug
DISK-TYPE FILTER.-- The disk filter (fig,
with magnetized contacts, and is placed in the
5-10) consists of a series of spacers and screens.
The screens and spacers are stacked alternately
in the housing. The spacers direct oil through the
screens as it flows through the assembly. The
screen mesh (usually measured in microns)
determines the size of foreign matter allowed to
pass through the filter.
MICRONIC-TYPE FILTER.-- The micronic
filter is similar to the cartridge filter used on a
car's oil filter, as shown in figure 5-11. It uses
either a paper or metal cartridge type of oil filter.
The paper filtering element is removed and
replaced, while the metal type is cleaned and
Each of the oil filter types mentioned in the
preceding paragraphs has certain advantages. The
filter types just discussed are generally used as
main oil filters. These filters strain the oil as it
leaves the oil pump. In addition to main oil filters,
there are also secondary filters throughout the
system. For instance, there may be a finger screen
filter to trap large metal pieces before the magnetic
Figure 5-11.-Filtering assembly.
drain plug. Also, there are the fine mesh screens
Figure 5-10.-Spacers-and-screens oil filter.