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Air Cleaners

The electrical circuit (grounded circuit) is as follows: From battery to ignition switch; switch to binding post on base, through magnet winding (16), through breaker spring, armature (10), base casting, through fuel pipes to battery.
Arcing of the contacts is reduced to the vanishing point by means of a "short circuited" secondary winding.
Capacity: About 7 gallons per hour through orifice rl„" dia., while lifting 18" to 20" and on a 6 or 12-volt battery.
Fuel pipe: For full capacity use rn" tubing; for installation where capacity is less than 6 gallons per hour use %" tubing; for duplex delivery use re" tubing.
INSTRUCTION No. 103
AIR CLEANERS:, Purpose; Types; Construction
Air Cleaners
Air cleaners are devices placed at the main air intake of carburetors, their purpose being to remove the road dust and deliver clean air to the carburetor.
It is said that automobile engines consume an average of 9,000 gallons of air for every gallon of gasoline and that if the air, containing road dust is placed under a powerful microscope it will be found that a portion contains minute particles of silica, an abrasive element, and also sand.
One manufacturer of an air cleaner states that tests have proved that 25 per cent to 75 per cent of the formation of carbon is silica or road dust and only from 5 to 25 per cent is actual carbon. Hence it is readily seen that by removing the road dust, carbon formation can be reduced considerably, as well as the wear on the moving parts.
Whether or not all road dust contains silica depends upon the locality and the kind of road dust, but there is no doubt that a large percentage of most road dust contains particles which are sharp, irregular crystals, hard enough to scratch the cylinder walls.
The air cleaner is not a new device. It has been used on tractor engines for a number of years.
Types of Air Cleaners
There are two major types of air cleaners: the wet and the dry types.
An example of the wet type is shown on page 989, which uses water to wash the air. On other makes oil is used instead of water. The wet type is con-fined to tractors and trucks.
The dry type is the type generally used on passenger cars, motor-coaches and trucks. The principle of construction and action may be: (1) filter; (2) centrifugal; (3) inertia.
Examples of some of the different makes of dry types of air cleaners are given below.
Operation: Air enters a large number of small openings (1) in outer shell at low velocity, and thus the coarse particles of dust are separated by gravity; specially constructed filtering material (2) consisting of a frame of galvanoid steel wire cloth covered with a piece of specially prepared felt, chemically treated, removes even the finest (those that cause wear) particles of dust, but readily permits air to pass through. Clean filtered warm air passes through this outlet to carburetor and engine, with the fine dust entirely removed.

Care: Under average conditions it needs no attention for 25,000 miles of use. However, when the car or truck is exposed to dust conditions such as are encountered on country roads or on construction work, the manufacturers recommend the cleaning of the felt every six months or every 5,000 miles of driving.

To clean: Unscrew the cap at the top of the retaining bolt and apply an air hose such as is used for inflating tires. With a few turns of the bolt in order to distribute the cleaning air blast throughout the interior of the fins, the insert is effectively cleaned. (\I'f'd. by Staynew Filter Corpn., Rochester, N.Y.)

Fig. 2. The United air cleaner. bus*r.o„...,w --This air cleaner uses what is termed by its manufacturer as a combination of centrifugal and centripetal force to eject the particles of dust and dirt from the air entering the carburetor. How this air cleaner is applied to a carburetor main air intake and its principle of action are described as follows:

Operation: The action of the United air cleaner depends upon centrifugal force.

Suction of the piston, during inlet stroke, draws air through the main air intake of the carburetor. With this device placed over the
main air intake of carburetor the passage of air through the cleaner turns the rotating member by means of a small fan. This fan is attached to a horizontal disk with four vertical vanes which by centrifugal force throw off and separate from the air stream particles of dust and dirt.

The lift valve moves up and down on a pin through its center. At extremely high speeds the suction of the engine raises this valve, thereby allowing the greater volume of air to pass into the carburetor.

The valve remains closed, however, at the driving range be-cause the suction of the engine is not great enough to raise it except at high speeds.

Clean air freed of dust, dirt and grit is drawn through the lift valve, as shown by arrows, into the carburetor past the spray nozzle where it mixes with gasoline and thence passes into the combustion chamber of engine.

Here is the principle in simplified form: you have seen the long chute down which the little folks slide in playgrounds and amusement parks. Now imagine that the youngsters were landed on a rapidly revolving circular table which was perfectly smooth. The youngsters would be deposited somewhere beyond the edge of the table very quickly.

That is the way the United air cleaner works. The particles of dust„ dirt and grit slide down an air current or chute on to a rapidly revolving table and are instantly shot over the edge. Being heavier than air, they are shot out of the way at a tremendous velocity.

Care: The hearing of the cleaner is supplied with felts which are thoroughly soaked with oil at the time the cleaner is assembled. In addition to this, oil bronze bushings of durex metal are used as guide bearings. The entire weight of the moving part lies upon a hardened steel ball which is highly polished, and because the weight of the moving part is extremely slight,
1 There are many other makes of air cleaners not shown here. See automobile trade magazines for advertisements.
Fig. 1. The Protectomotor, a filtering type of air cleaner, which filters the air through very fine textile fabric. It is claimed that
the effective filtering area is two hundred times the area of the carburetor air intake opening.

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