Types of Air Cleaners
Air Cleaners and It's Types
The fuel system provides a combustible air-fuel mixture to the engine. The mixing of air
and fuel takes place in the carburettor. For the normal running of the petrol engine, one
part of petrol requires 16 parts of air by weight. It is a great amount of air that passes
through the carburettor to the engine in comparison to petrol.
The air is likely to contain dust and dirt. If the air is not cleaned before it exerts the
carburettor, the dust and dirt particles will seriously damage the engine. They will foul
the carburettor parts and spark plug, increase abrasive wear on piston, piston rings,
cylinder walls, bearings and any relative moving parts.
Therefore, the air must be cleaned before it enters the carburettor. For this purpose, an
air cleaner is used. It is mounted on the air horn or air entrance of the carburettor. All
air entering the engine through the carburettor must first pass through the air cleaner.
The air cleaner not only cleans the air by removing the dust and dirt particles but also
muffles the noise resulting from the intake of air through the carburettor, muffle and
valve ports. In addition, the air cleaner acts as a flame arrester in case the engine
backfires through the carburettor.
Backfiring occurs at certain times due to the ignition of the air-fuel mixture in the
cylinder before the intake valve closes. When this happens, there is a momentary flask-
back through the carburettor. The air cleaner prevents this flame from spreading
through the carburettor and possibly igniting the petrol fumes outside the engine.
Types of Air Cleaners in Engine
Air cleaners are classified on the bases of principles of filtration and nature of filtering
material. The type of filter adopted for a particular engine depends upon the
atmosphere in which the engine has to operate.
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Types of Air Cleaners
The air cleaners generally used are of the following types:
1. Oil bath type air cleaner
2. Dry-type air cleaner
3. Oil wetted type air cleaner
4. Paper pleated type air cleaner
5. Centrifugal type air cleaner
1. Oil Bath Type Air Cleaner
It is a heavy-duty air cleaner. It is designed in a variety of shapes. The type shown in
figure is designed to be placed on the top of the carburettor and to be clamped to the air
horn. It consists of a filter element saturated with oil. At the bottom, there is a separate
oil pan. The operation of air cleaning is carried out in two stages.
In the first stage, the airstrikes on the oil surface and then reverse upward into the filter
element. The dust particles applied to the oil surface and absorbed by it. In the second
stage, the partly cleaned air passes through the filter element in which the remaining
dust particles are retained. Finally, the cleaned air passes to the carburettor through the
passage away.
Depending on the severity of operation, this type of air cleaner is cleaned periodically.
The filter is removed and cleaned carefully in petrol. The oil in the cleaner is also
replaced.
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Types of Air Cleaners
2. Dry Type Air Cleaner
It is a light-duty air cleaner. It consists of a cleaning element only and not the oil bath.
The cleaning element is a specially pleated element, over which is put a fire mesh screen
to provide strength. This cleaning element is enclosed in a silencing chamber. The figure
shows the part of a dry-type air cleaner.
3. Oil Wetted Type Air Cleaner
It consists of a filtering element generally wire mesh, coated with an oil film. The air
passes through this element, and the dust particles of the air adhere to the oil film. This
type of air cleaner should be cleaned periodically, about every 800 km, by washing the
wire mesh in petrol or paraffin. After drying is properly, coat it with engine oil, allow it
to drain and again fit it for working.
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Types of Air Cleaners
4. Paper Pleated Type Air Cleaner
It consists of a filtering element of the resin-impregnated paper. This type of air cleaner
is made in the form as shown in the figure. It has a high filtering efficiency. By pleating
the paper element, a large filtering surface is provided and yet restriction of airflow is a
minimum. The element should be cleaned periodically, about every 20,000 km.
5. Centrifugal Type Air Cleaner
The figure shows a centrifugal type air cleaner. In this type of air cleaner, a whirling
motion is given to the air due to which heavy dust particles are thrown out by the
centrifugal force to the periphery of the casing, where they leave through slots.
The main airflow passes through vanes set at an angle, to correct the airflow to a
straight direction, and then enters the main air cleaner. The air is not perfectly cleaned
by this cleaner and hence it acts as first stage cleaner on installations dealing with heavy
dust concentrations. It is known as a centrifugal cleaner.
Read Next:
1. Types of Combustion Chamber and Cylinder Head
2. What is Governor? Three Major Types of Governors Used in Automobile Engine
3. Suspension System: Types, Parts, Working
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