1. The cartridge-type element (fig. 6-24) fits into a
permanent metal container. Oil is pumped
under pressure into the container where it passes
from the outside of the filter element to the
center. From here, the oil exits the container.
The element is changed easily by removing the
cover from the container.
2. The spin-on filter (fig. 6-24) is completely self-
contained, consisting of an integral metal
container and filter element. Oil is pumped into
the container on the outside of the filter element.
The oil then passes through the filter medium to
the center of the element where it exits the
container. This type of filter is screwed onto its
base and is removed by spinning it off.
The elements themselves may be either metallic or
nonmetallic. Cotton waste or resin-treated paper is the
most popular filter mediums. They are held in place by
sandwiching them between two perforated metal
sheets. Some heavy-duty applications use layers of
metal that are thinly spaced apart. Foreign matter is
strained out, as the oil passes between the metal layers.
There are two filter configurations. These are the
full-flow system and the bypass system. Operations of
each system is as follows:
Figure 6-24.Oil filters.