Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a device for
removing pollutant particles, particularly lead
particles,from the exhaust gases of an internal
combustion engine.
An object of the invention is to provide a
device as aforesaid which is efEective both as
a silencer of the engine exhaust and as a means of
removing lead particles from the exhaust gases.
According to the invention there is provided a
device for removing pollutant particles, particularly
lead particles, from the exhaust gases of an internal
combustion engine, characterised by the fact that
it comprises,in combination: a cylindrical casing
having-first and second end walls; two dividing walls
inside the cylindrical casing, subdividing the interior
of the casing into three chambers: a first end chamber,
an intermediate chamber and a second end chamber;
an axial inlet pipe extending through the first end wall
of the casing into the first end chamber up to the first
dividing wall, said inlet pipe having holes for the
passage of the exhaust gases in~o the space between
the said pipe and the internal surface of the
cylindrical casing; an annular chamber, containing
a porous packing, disposed within the first end
chamber and adjacent the internal surface of the
casing, delimited internally by a cylindrical wall
which is fixed to the casing and provided with holes
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for the passage of the exhaust gases into the annul~r
chamber, the first dividing wall also having holes,
arranged circumferentially around the inlet pipe, for
the flow of the exhaust gases into the intermediate
chamber; an axial pipe, disposed inside the casing
extending from the first dividing wall and passing
through the second dividing wall and the second end wall
of the casin~; a number of guide baffles, extending axi-
ally within the intermediate chamber between said axial
pipe and the internal surface of the casing, the guide
baffles being adapted to impress on the exhaust gases
a helicoidal vortex motion, the second dividing wall
having an annular opening surrounding the axial pipe,
for the passage of the exhaust gases into the
second end chamber; an annular chamber within the
second end chamber, delimited by said axial pipe and
enclosed by a frusto-conical wall, which encourages a
centrifugal flow of the exhaust gases, compelling
said gases to flow through said chamber and to reverse
their flow directions, the space between the frusto-conical
wall and the wall of the casing being filled with
a porous packing; a number of radial axially extending
partitions placed inside the said annular chamber
and surrounding said axial pipe; said partitions having
their radially outer ends in contact with a shroud, and
being adapted to straighten the vortex flow of the
exhaust gas s after the latter have reversed their flow
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direction in the annular chamber, the said axial
pipe being also provided with holes for the passage
of the straightened flow of exhaust gases into the
axial pipe for discharge to an outlet end of said pipe.
The invention will be further described, by way of
non-limiting example, with reference to the accompanying
drawings, in which:
Figure 1 is an axial sectional view of a device
according to one embodiment of the invention, and
Figures 2 to 6 are respective cross-sectional views
of the device taken on the lines II-II, III-III, IV-IV,
V-V and VI-VI respectively in Figure 1.
Referring to the drawings,the illustrated
device for removing lead particles from the exhaust
gases of an internal combustion engine includes a
cylindrical casing 1 made by forming a rectangular
steel sheet into a tube and welding the longer edges
together along a seam 2. The casing 1 has opposite
end walls 3, 4,-each of which is formed by a disc
welded externally to the wall of the casing 1.
Two transverse dividing walls 5, 6 are fixed
within the casing 1, each formed by a disc of sheet
steel welded peripherally to the inside surface
of the ¢asing 1, and dividing the in~erior of the casing
1 into three chambers, a first end chamber 7, an
intermediate chamber 8 and a second end chamber 9.
An exhaust gas inlet pipe 10 passes through the
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end wall 3 of the casing 1 and extends into the first
end chamber 7; the pipe 10 is welded at its internal
end to the dividing wall 5, which closes this end of
the pipe 10. The wall of the pipe 10 within the
casing is perforated with holes 11, uniformly
distributed on the surface of the pipe 10, for the
passage of the exhaust gases which flow through the
pipe 10 into the annular space between the external
wall of the pipe 10 and the wall of the casing 1.
An annular chamber 12, one wall of which is
formed by the internal surface of the casing 1 is
located in the chamber 7, the chamber 12 having an
inner cylindrical wall 13 perforated with holes 14.
The wall 13 is formed by two semi-cylindrical shells 15,
16 provided with longitudinal edge flanges 15a and 16a
which are welded together and are also welded to the
internal surface of the casing 1 (Figure 2).
The annular chamber 12 is filled with a porous
material, formed pxeferably by wire mesh or by pieces
of expanded metal.
The dividing wall 5 has a number of holes 17
distributed circumferentially around the inlet pipe 10
to allow the passage of the exhaust gases from the
chamber 7 into the intermediate chamber 8 (Figure 3).
An axial pipe 18 extends within the casing 1 and
is welded at one end to thP dividing wall 5, the pipe
18 passing through the dividing wall 6 and the end wall
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4 of the container 1.
Within the chamber 8, in the space defined between
the external surface of pipe 18 and the internal surface
of the casing 1, three symmetricallyarranged curved
guide baffles, 19, 20 and 21 are mounted. As shown in
Figure 4, each baffle 19 t 20, 21 comprises a cylindrical
segment of sheet steel fixed at its opposite axial ends
to the dividing walls 5 and 6, and disposed in such a
way as to compel the exhaust gases to flow through
the chamber 8 with a helicoidal vortex movement. The
dividing wall 6 is spaced from the external surface
of the axial pipe 18 by an annular opening 22 which
allows the exhaust gases to pass from the chamber 8
into the second end chamber 9.
A tubular wall 23 having a substantially frusto-
conical portion tapering towards the end wall 4 is
disposed within the chamber 9, and fixed therein by
welding of its larger cross-section end to the
dividing wall 6, its smaller cross-section end being
fixed to the external surface of the axial pipe 18 .
adjacent the end wall 4. An annular chamber 24 is
defined between the extPrnal surface of the pipe lB
and the internal surface of the tubular wall 23. The wall
23 is provided with slots 25 for the passage of the
exhaust gases from the chamber 24 into an annular
chamber ~6 delimited internally by the frusto-
conical surface of the tubular wall 23 and externally
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by the internal surface of the casing 1. The annular
chamber 26 is filled with a porous material,
preferably wire mesh or pieces of expanded metal.
A sheet metal strip 27 folded into corrugations
(Figure 5) is placed around the external surface of
the pipe 18 inside the chamber 24 so as to form radial
partitions 28. The outer ends of the partitions 28 are
in contact with a shroud 29 coaxial with ~he pipe 18
and fixed to the partitions 28 by means of three
radially inwardly projecting lugs 30 on the shroud.
The axial pipe 18 has, adjacent the radial
partitions 28, four slots 32, angularly equidistant from
each other. After a reversal in the direction of
flow the exhaust gases flow between the radial partitions
28 the exhaust gases flow through the slots 32 into
the interior of the axial pipe 18. A deflector 31 is
fixed to the shroud 29 and to the external wall of
the axial pipe 18, for the deflection of the exhaust
gases radially inwardly through the slots 32.
The operation of the illustrated device i5 as
follows:
The exhaust gases of an internal combustion engine
j~ are directed into the inlet pipe 10. Since there
'~ are no holes in the part of the dividing wall ~S which
closes the end of the pipe 10, the exhaust gases are
compelled to pass outwardly through the holes 11 o~ the
pipe 10, flowing into the space between the external
surface of the pipe 10 and the internal sur$ace ~
casing 1. Some of the exhaust gases flow into the
chamber 12 through the holes 14; in the chamber the
heavier lead particles contained in the exhaust gases
flow into and remain trapped in the packing material
in said chamber.
From the chamber 12 the exhaust gases pass through
the holes 17 in the dividing wall into the chamber 8.
In flowing through the chamber 8 the guide baffles 19,
20, 21 impress on the flow of exhaust gases a helicoidal
vortex motion. The vorte~ flow of exhaust gases around
the outside of the axial pipe 18, passes through the
annular opening 22 into the chamber 9. The vortex
flow of exhaust gases is deflected outwardly by the
deflector 31 to flow around the shroud 29 into the
chamber 24.
The gases flowing into the chamber 24 keep their vortex
motion by virtue of the decrease of the flow cross-
section of the-chamber due to the conicity of the wall
23. On reaching the smaller cross section end of the
chamber 24 the exhaust gases are compelled to reverse
their direction of flow in the chamher 24.. The
centrifuging thus effected will force the lead particles
contained in the exhaust gases, which had not been
trapped in the chamber 12, against the frusto-conical
part of the wall 23~ The slots 25 allow these lead.
particles to pass into the chamber 26 where they are trapped
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by the packing material therein.
The exhaust gases flowing in the reverse direstion
in the chamber 24 are compelled to pass between the
radial partitions 28 which eliminate the vortex flow
previously impressed on the gases. The straightened flow
is forced by the deflectors 31 to pass inwardly through
the slots 32 into the pipe 18, through which the
exhaust gases are then discharged to the atmosphere.
It will be evident that by means of the device
according to this invention lead particles and other
heavy particles contained in the exhaust gases o~ an
internal combustion engine are effectively removed from
the exhaust gases by means which take advantage both
of the principle of inertial impact, due - to
which the heavier particles are separated, and of the
principle of centrifugal separation.
It will be understood that practical embodiments
of the invention may be widely varied with respect to what
has been described and illustrated by w~y of non-
limiting example, without departing from the scope ofthe invention.
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