TM 5-3810-300-24&P-3
3.1
AIR CLEANER
The air cleaners are designed to remove the foreign
matter from the air, pass the required volume of air for
proper combustion and scavenging, and maintain their
efficiency for a reasonable period of time before requiring
service.
Air cleaners have been classified as light duty or heavy
duty according to their application and dirt holding
capacity.
The importance of keeping dust and grit-laden air out of
an engine cannot be overemphasized since clean air is
so essential to satisfactory engine operation and long
engine life. The air cleaner must be able to remove fine
materials such as dust and blown sand as well as coarse
materials such as chaff, sawdust, or lint from the air. It
must also have a reservoir capacity large enough to
retain the material separated from the air to permit
operation for a reasonable period before cleaning and
servicing are required.
Dust and dirt entering an' engine will cause rapid wear of
valve mechanism with a resultant loss of power and high
lubricating oil consumption. Also, dust and dirt which is
Fig. 1 - Light Duty Oil Bath Air Cleaner and Silencer
allowed to build-up in the air cleaner passages will
Assembly
eventually restrict the air supply to the engine and result
in heavy carbon deposits on the pistons and valves due
down through the center tube. At the bottom of the tube,
to incomplete combustion.
the direction of air flow is reversed and oil is picked up
Light Duty Oil Bath Type Air Cleaner
from the oil reservoir cup. The oil laden air is carried up
Light duty oil bath type air cleaners, Fig. 1, consists
into the separator screen where the oil which contains
essentially of a wire screen element supported inside a
the dirt particles is separated from the air by collecting on
cylindrical housing which contains an oil bath directly
the separator screen.
below the element. Air drawn through the cleaner
passes over the top of the oil bath. The air stream
A low pressure area, (Fig. 3), is created toward the
direction reverses when the air impinges on the oil in the
center of the air cleaner as the air passes a cylindrical
sump and is then directed upwards by baffles. During
opening formed by the outer perimeter of the central tube
this change in the direction of air flow, much of the
and the inner diameter of the separator screen. This low
foreign matter is trapped by the oil and is carried to the
pressure is caused by the difference in air current
sump where it settles out. The air passes upward
velocity across the opening. The low pressure area, plus
through the metal-wool elements where more dust and
the effect of gravity and the inverted cone shape of the
the entrained oil are removed. A second change of air
separator screen, causes the oil and dirt mixture to drain
direction, at the top of the cleaner directs the air
to the center of the cleaner cup. This oil is again picked
downward through the center tube and into the blower
up by the incoming air causing a looping cycle of the oil,
inlet housing.
however, as the oil is carried toward another cycle,
Heavy Duty Type Air Cleaner
In all heavy duty air cleaners, Fig. 2 air is drawn through
the air inlet hood, which acts as a cleaner,
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