US 2825318 A
Description (OCR text may contain errors)
AIR CLEANER Filed Deo. 28, 1956 FIEZ.
JAMES H. MA F1 y BY N5 ELD ATTYS,
c ,A V2,825,318 :PatentedMar. 4,1958
' 2,325,318 AIR ,CLEANER (JamesH.iMansfield, Philadelphia, Pa.
Application DecemberzZS, 1956, Serial No. 631,261
3 Claims. '(Cl. 1215-4156) This invention relates-,to apparatus forsupplying clean air to the carburetor of aninternal combustion engine, or to otherdevice or mechanism rwhich requires a ysupply of substantially dust-free air.
It is well known that dust or othersolid matter of any kind carried by incoming air into a carburetor or engine combustion chamber tends to-clog the jets and valves of the carburetor and chamber and thereby to render the engine inoperative until the rsolidrnatter is removed from all small oriiices and openings through which the air must pass in controlled quantities. Furthermore, internal enginefparts are subjected to `excessive wear if dirt or dust is permitted to flow into Athe combustion chamber. Two cycle engines are especially vulnerable to foreign particles, due to the type of intake-valves used, which are either reed or rotary. f The necessity of providing air-cleaning means is accordinglyrrecognized.
One ofthe `nowconventional methods of cleaning air on its way toy acarburetoristopass it through a filter, of which there are-various types. Such filters are, in general, elhcient andsatisfactory, but have one drawback, viz.: they accumulate ine-themselves the solid matter filtered out of the air as itpassesthroughthem, with'the eventual result of reducing the amount kof rair that can pass through the iilterin consequence of which Vthe ,carburetor receives graduallyless and lessair until it isvunable to deliver the requisite volume of fuel-'laden air Vto the engine or to maintain the proper-mixture of air and fuel necessary to good engine performance. Accordingly, Yit is necessary to clean the lter more or less frequently. Moreover, lilters may get wet and freeze solid during cold weather use.
This invention obviatesthe need of an air filter and delivers substantially dust-free air, at the'same time automatically disposing of the solid matter removed from the air.
This invention also delivers air to the carburetor at constant and slightly more than atmospheric pressure, which contributes to the eliiciency of the carburetor.
This invention is Yapplicable to any air cooled internal combustion engine or other mechanism which comprises an enclosed fan which functions so as to produce a centrifugal flow of air the course of which may subsequently be changed and so channelled and directed as to be useful.
It is conventional to provide such a fan with a screen over its intake opening. Sometimes more than one screen is incorporated, and in some instances a screen is so mounted as to rotate with the fan. Such screens, however, must be relatively coarse and open, so that they function only to exclude large particles such as chips, pebbles, grass, leaves, straw, feathers, strings or other such bodies which may be present in the air in the vicinity of the fan and associated mechanism. The screen does not lter the air to the extent of excluding small particles, for the exclusion of small particles is not necessary to the continuous and satisfactory functioning of the fan.
In the accompanying drawings:
Fig. 1 is a top view of a'small internal combustion engine made in accordance with the invention;
Fig. 2 is an end elevational view of theengine from the 'the power takeoff side;
Fig. 3 is a side viewv of the engine with a portion of the fan shroud or housing broken open so as to render the fan visible;
Fig. 4 is a view in perspective of the fan detached fromA the engine;
Fig. 5 is a fragmentary'side elevation and partial sectional view ofan engine with a different type of fanwithin the scope of the invention, and
Fig. 6 is a sectional view on the line 6,6, Fig.5.
Withr reference 'to the drawings, the invention comprises a rotary fan 1 of centrifugal type which in operation tends to impel air radially into a shroud 2. The shroud Z encloses the fan and has a screened opening 3 adapted to admit outside air axially to oneV side of the fan adjacent the axis 4 of the latter, said shroud also having another opening 5 adjacent the periphery and'in the present instance at the top of the fan adaptedto discharge the air in-a desired direction. A radial baie 6 forms a solid wall in proximity to the side of the fan-remote from the admission opening 3; and a tube 7, constituting the air supply duct of a carburetor 8, has its intake end in proximity to the said bafe as illustrated. The bafe may be stationary or may be integral with or otherwise rotatable with the fan. The inner or'rear wall 9 of the shroud extends upwardlyin spaced relation to and at the back of the baile 6 to a point near the outer peripheryof the fan and in the present instance the upper edge 10 of thewall defines the lower edge of the discharge opening 5.
A suitable assembly in accordance with the principle rof the invention, therefore, consists of a fan having a radial Wall on the side of its fins or blades which lies remote from the intake opening of a'shroud, so that only air newly admitted through said opening reaches the axial area of the fan, said baffle providing a space adjacent the shaft of the fan on the side remote from the said intake opening, which space is accessible during operation only to air which has been subjected to the action of the ns .or blades of the fan.
It is not necessary that the solid wall which functions as a baffle extend to the periphery of the fan. lts essential location and extent is adjacent the axis of the fan.
l A particular advantage from the standpoint of economy and practicability arises from the fact that the fan and other component assemblies and parts comprised inthis invention are to be found in many air cooled internal combustion engines in substantially the required form, while in practically all others a fan Yconforming to the functional requirements of this invention can be substituted and a baffle provided separately if not made integral with the fan, and such provisions will perform all of the functions required therefrom for other purposes, the prime purpose of a fan `in operative combination with an air cooled internal combustion engine being to circulate air to and around the engine cylinder or cylinders.
A typical air cooled engine assembly is illustrated in Figs. 1 to 4 of the drawings wherein, in'addition to the elements previously described, the crankcas'eof the engine is shown at 12, the fan 1 being mounted on one end of the shaft 13 of the engine. The engine cylinder or cylinders 14 occupy an upright position in the discharge opening 5 of the shroud 2, said opening terminating in the present instance in louvers 15 which shield the cylinder.
at a filter) to convey cleaned air to the carburetor, said opening being so disposed as to allow the movement into said tube of air from which dust and other solid matter hasbeen removed by the operation of the fan.
In imparting velocity to air the fan incidentally imparts velocity to the dust or otherv solid particles present in the air. The fan with its shrouding is adapted to deliverl a major portion of the air passing through it to a selected locality, radially and/ or tangentially, beyond the periphery of the fan where cooling effect is desired, and dust and other small particles of solid matter are carried along with such major portion ofthe air, without detriment to the cooling function since there is ample space for its passage.
Such minor portion of the air as does notjoin the main current and promptly escape, deviates from the direction in which the dust and other particles are impelled by the direct action of ,the fan or by the resulting (partially deflected) current. Inertia of motion causes the dust and other solid particles to `continue to travel in the direction in which they are impelled by the fan or by the air current travelling at the highest speed with the least change of direction` Accordingly, the dust and other solid particles do not travel with the slower moving air that eddies back into space near the fan shaft, remote from the main outlet and on the side of the bathe remote from the influx of outside air, where an air opening is provided for its exit into a tube leading to the carburetor.
In an experimental operative embodiment of this invention, a trap with a removable cap at the bottom was provided in the tube leading from such an opening to the carburetor, but even after running the engine for a protracted period of time no deposit of dust particles or other foreign matter was found in the trap. Meantime, throughi out extensive and lengthy service tests the engine maintained peak performance and no adjustment or servicing was necessary as a result of dust or foreign matter entering the carburetor.
Incidental to directing the flow of air from the fan to the location desired, and for the purpose of so doing, a fan such as described is necessarily associated with a surrounding shroud which confines the air except Where its egress is desired. Such a surrounding shroud functions to restrain the escape in undesired directions of air driven by the moi tion of the fan, and by confining said air to predetermined course of flow, and `in so doing brings about the accumulation within itself of air pressure slightly in excess of and more uniform than the atmospheric pressure outside of the shroud. This increased and uniform pressure is effective at the opening provided for the escape of air which passes therefrom to the carburetor, and results in improved functioning of the carburetor.
1. In combination with an air cooled internal combustion engine comprising `a carburetor, a centrifugal fan having air-impelling blades, bathe means at one axial side ot' the fan restricting the axial ow of air to the blades to one side only of the fan, shroud structure enclosing said fan and baffle and having an opening for admission of air axially to the said one side of said fan, and having also an opening for the discharge of air from the periphery of said fan, and an opening in said shroud structure adjacent the axis of said fan and on the side of said baffle remote from said blades for the delivery of air to the carburetor.
2. In combination, a centrifugal fan having an axis, shroud means substantially enclosing said fan and having an inlet port for admission of air axiallyto one rside only of said fan, said shroud means also having a discharge portiradially remote from said axis, a radial baffle at the other side of said fan, and air-withdrawal port means having an entrance near said axis between said baffle and said shroud for the withdrawal, `for external use, of air which has passed radially through said fan and around said baffle into space near said axis between said baffle and the side of said shroud opposite said inlet port.
3. Apparatus for providing a supply of air from which any suspended solid matter has been removed by centrifugal impulsion, said apparatus comprising a centrifugal fan having air impelling blades and an axis, a shroud substantially enclosing said fan, an inlet opening in said shroud adjacent said axis for admission of air axially to one side only of said fan, a discharge port in said shroud radially remote from said axis for the discharge of centrifugally impelled air and solid matter suspended therein, a bale located within said shroud on the other side of said fan between said fan and a side of said shroud opposite said inlet opening, the saidbafile extending radially from said axis and having an edge remote from said axis, said bafde and said side of said shroud defining between them a space adjacent said axis into which air can enter only after first passing beyond the said edge of said baille, and port means for withdrawing, for use outside of the apparatus, air which has passed around the edge of said baffle into said space.
References Cited inthe file of this patent UNITED STATES PATENTS 1,922,200 Frank Aug. l5, 1933