Note: Descriptions are shown in the official language in which they were submitted.
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CYCLONE TYPE DIRT SEPARATOR
AND
ELECTRIC VACUUM CLEANER
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a cyclone type dirt separator which is
provided at an intermediate point of the suction tube of an electric vacuum
cleaner
and further relates to an electric vacuum cleaner that uses such a separator.
2. Description of the Related Art
In typical electric vacuum cleaners, suction air that involves dirt that is
sucked in via a suction fitting (suction nozzle) is led to the cleaner main
body via a
suction tube. Here, the suction air that contains dirt passes through a filter
installed in the cleaner main body, and dirt is collected by this filter.
In collection of the dirt, if relatively large pieces of dirt such as paper
debris,
sludge and the like are contained in large quantities in the dirt that is
sucked in,
the filter quickly becomes clogged, so that the suction capacity soon drops.
Accordingly, the filter must be cleaned frequently, and this frequent filter
cleaning
is in fact a problem of poor efficiency. In order to solve this problem, a
system has
been proposed in which a cyclone type dirt separator is interposed at an
intermediate point of the suction tube that connects the suction fitting and
the
cleaner main body, so that the cyclone type dirt separator captures and
removes
relatively large pieces of dirt.
In the cyclone type dirt separator disclosed in Japanese Patent No.
3102864, the lower end of an exhaust tube that sucks air from the vicinity of
a
spiral flow into the cleaner main body is closed, numerous fine through-holes
are
formed in the outer circumferential surface of this tube, and air is sucked
from
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these fine through-holes and discharged into the cleaner main body. In this
structure, the dirt that is separated from the spiral flow is collected in a
contaminant collection trough (a dirt collection part) that extends downward
and
surrounds the exhaust tube.
On the other hand, in the cyclone type dirt separators of Japanese Patent
Application Laid-Open (Kokai) Nos. 2003-735336 and H10-85159, the open lower
end of an exhaust tube is caused to face the vicinity of the center of the
dust
separating section that generates a spiral flow, and the lower part of the
dust
separating section is communicated with a dust collecting part that is
provided
below the dust separating section via a dust collecting opening that is in the
form
of a funnel. In this structure, the dirt that is separated by the spiral flow
in the dust
separating section drops into the dust collecting part via the dust collecting
opening.
However, in the system of Japanese Patent No. 3102864, dirt separated by
centrifugal force in the spiral flow is conducted downward along the inside
circumferential wall of the contaminant collecting trough; accordingly, the
separation of dirt and air can be accomplished with good efficiency. However,
since the fluid motion of the spiral flow enters the interior of the
contaminant
collecting trough along the inside circumferential wall of the contaminant
collecting
trough, the air inside the contaminant collecting trough undergoes a spiral
flow.
As a result, the dirt that collects in the bottom of the contaminant
collecting trough
is entrained by the fluid motion (spiral flow) of this air and may be
discharged from
the exhaust tube. This dirt causes clogging of the filter of the cleaner main
body.
In the systems of Japanese Patent Application Laid-Open (Kokai) Nos.
2003-135336 and H10-85159, a spiral flow is generated in the dust separating
section, and dirt is collected in the dust collecting part separated by the
dust
collecting opening installed in the funnel-form bottom. Consequently, the
spiral
flow inside the dust separating section tends not to enter the dust collecting
part.
Accordingly, it would appear that the amount of dirt that is entrained by the
spiral
flow in dust collecting part is small compared to that seen in the system of
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Japanese Patent No. 3102864.
However, a spiral flow would be generated inside the dust collecting part
according to the amount of suction air, so that dirt may be entrained; and
secure
prevention of the entrainment of dirt in the dust collecting part is
difficult.
Furthermore, since the dust collecting part is installed separately from the
dust
separating section, the total length of the structure increases, causing a
problem
of increased size of the apparatus.
BRIEF SUMMARY OF' THE INVENTION
Accordingly, in a preferred embodiment of the present invention there is
provided a cyclone type dirt separator which prevents the entrainment of dirt
accumulated in the contaminant collecting trough or dust collecting part by
spiral
flow of air, thus preventing the exhaust of entrained dirt and intake of such
dirt into
the cleaner main body.
In another preferred embodiment of the present invention there is provided
an electric vacuum cleaner that is equipped with such a cyclone type dirt
separator.
According to a further preferred embodiment of the present invention, there
is provided a cyclone type dirt separator, which is interposed at an
intermediate
point of the suction tube connecting the suction fitting and a cleaner main
body of
an electric vacuum cleaner, and which separates dirt from the suction air
containing dirt that is sucked in from the suction fitting; and in the present
invention, the separator is comprised of:
a dirt separating section which causes the suction air to make a
spiral flow and conducts air from the vicinity of the center of this spiral
flow to the
cleaner main body,
a dirt collection chamber which is mounted on this dirt separating
section from below and causes the dirt separated from the spiral flow to drop
so
that the dirt is collected in said dirt collection chamber, and
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a recessed portion formed in the vicinity of the inside bottom center
of the dirt collection chamber so as to be recessed downward.
The invention thus provides a unique structure of the present invention for
an electric vacuum cleaner having
a cleaner main body provided with an electrically driven air blower;
a suction tube having opposed ends, one end thereof being
connected to a vacuum suction port of said cleaner main body;
a suction fitting attached to the other of said opposed ends of said
suction tube; and
a cyclone type dirt separator provided at an intermediate point
between said ends of said suction tube, said cyclone type dirt separator being
adapted to create suction air containing dirt to be sucked in through a
suction
fitting and form a spiral flow to separate dirt from said air and to cause
separated
dirt to drop into a substantially tubular dirt collection chamber and to be
collected
in said dirt collection chamber; the improvement wherein
said dirt collection chamber includes an inside bottom center and a
recessed portion, the recessed portion formed proximate said inside bottom
center of said dirt collection chamber and being recessed generally downwardly
relative thereto.
In this structure of the present invention, since the recessed portion is
formed in the vicinity of the center of the inside bottom of the dirt
collection
chamber, the dirt that enters the dirt collection chamber is conducted into
the
inside bottom surface and is collected in the recessed portion. In addition,
even if
a spiral flow is generated in the dirt collection chamber, since this spiral
flow tends
not to enter the sunken recessed portion, no entrainment of the dirt
accumulated
in the recessed portion occurs, and dirt in the vicinity of the inside bottom
likewise
tends not to become entangled and entrained with the dirt accumulated in this
recessed portion. Accordingly, dirt that has once entered the dirt collection
chamber is prevented from being discharged from the exhaust tube, so that the
need for frequent cleaning of the filter inside the cleaner main body is
eliminated.
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Accordingly, in the electric vacuum cleaner of the present invention, dirt
that has once entered the dirt collection chamber of the cyclone type dirt
separator
is prevented from being discharged from the exhaust tube, and the need for
frequent cleaning of the filter inside the cleaner main body is eliminated.
In the cyclone type dirt separator of the present invention, the separating
section may comprise an exhaust tube, which is disposed substantially in
coaxial
with the central axis of the spiral of the spiral flow, whose lower end is
closed off,
and which exhausts air via the exhaust openings in the circumferential
surface;
and the dirt collection chamber may have a substantially tubular shape that
extends downward while surrounding this exhaust tube. In this case, the dirt
that
is separated by the centrifugal force arising from the spiral flow can be
conducted
into the inside bottom of the dirt collection chamber with good efficiency, so
that
the dirt separation is done efficiently. Furthermore, one part (the upper
part) of
the dirt collection chamber surrounds the exhaust tube and forms an integral
unit
with the separating section, thus generating a spiral current of air;
accordingly, this
structure contributes the overall size reduction.
Furthermore, with a substantially flange-form baffling plate which narrows
the air flow path between this baffling plate and the inside wall of the dirt
collection
chamber, the entry of the spiral flow into the inside bottom of the dirt
collection
chamber is prevented, so that the entrainment of dirt accumulated in this
inside
bottom and the outflow of such dirt together with the exhaust can be much more
securely prevented.
In the present invention, the inside surface in the vicinity of the opening of
the recessed portion and the inside bottom surface of the dirt collection
chamber
are not smoothly continuous, or such surfaces meet with a ridge in between.
For
example, the inside bottom surface of the dirt collection chamber can be
formed
as a so-called artillery shell-form curved surface in which the diameter is
smoothly
reduced downward, and this curved surface and the opening circular edge of the
recessed portion abuts at an obtuse angle to form a substantially annular edge
shape. With this structure, if a spiral flow occurs in the inside bottom, the
spiral
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flow is less likely to enter the recessed portion.
The recessed portion can be of a substantially cylindrical shape with a
closed bottom. However, the present invention is not limited to this
structure, and
a square tubular shape recessed portion that has a closed bottom or the like
can
be also used. By way of setting the diameter of the opening of the recessed
portion at approximately 1/2 to 1/3 of the diameter near the center of the
dirt
collection chamber, the intrusion of the spiral flow can be sufficiently cut
off while
maintaining the capacity (volume) of the recessed portion at a large value.
In the present invention, it is preferable that the cyclone type dirt
separator
be installed in the connecting portion between a flexible tube and an
extension
tube that constitute the suction tube of an electric vacuum cleaner; however,
this
cyclone type dirt separator can be disposed, for instance, in the vicinity of
the tip
end of the extension tube and in the vicinity of the vicinity of the rear end
of the
flexible tube (immediately before the cleaner main body or the like).
BRIEF DESCRIPTION OF THE DRAWINGS:
Reference will now be made to the accompanying drawings illustrating preferred
embodiments in which:
Figure 1 shows the electric vacuum cleaner of the present invention
equipped with a cyclone type dirt separator according to one embodiment of the
present invention;
Figure 2 is a sectional side view of the cyclone type dirt separator;
Figure 3 is a sectional view of the essential portion of the cyclone type dirt
separator;
Figure 4 is a sectional view taken along the line IV-IV in Figure 3;
Figure 5 is a sectional view taken along the line V-V in Figure 4; and
Figure 6 illustrates the exhaust openings of the exhaust tube inside the dirt
separator.
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DETAILED DESCRIPTION OF THE INVENTION
In Figure 1, the reference numeral 10 is a cleaner main body, and this
cleaner main body 10 is equipped with a filter 12 and an electrically driven
air
blower 14. A suction tube 16 connected to the cleaner main body 10 is
comprised
of a flexible tube 18 and an extension tube 20, and a cyclone type dirt
separator
22 is provided at an intermediate point of this suction tube 16. The
electrically
driven air blower 14 generates a suction force by rotating a fan (not shown)
at
high speed with an electric motor (not shown).
The electric vacuum cleaner 10 is indeed usable without a cyclone type dirt
separator 22; and in this case, the flexible tube 18 (or the forward end of
the
flexible tube 18) and the extension tube 20 (or the rear end of the extension
tube
20) are directly connected to each other to form the suction tube 16. When a
cyclone type dirt separator 22 is used, the cyclone type dirt separator 22 is
interposed between the flexible tube 18 and the extension tube 20. In other
words,
the forward end of the flexible tube 18 is connected to the rear end of the
dirt
separator 22 (or to the exhaust tube 32, which will be described later, of the
dirt
separator 22), and the rear end of the flexible tube 18 is connected to the
cleaner
main body 10, and a suction fitting (suction brush) 24 is attached to the
forward
end of the extension tube 20 and the rear end of the extension tube 20 is
connected to the dirt separator 22 (or to the suction intake tube 34, which
will be
described later, of the dirt separator 22) as shown by arrows in Figure 1.
When a switch (not shown) on the cyclone type dirt separator 22 is turned
on, the electric motor of the air blower is started; and an air suction
negative
pressure is generated in the suction fitting 24. Air that contains dirt is
sucked in
via the suction fitting 24, and relatively large pieces of dirt are separated
from this
suction air by the cyclone type dirt separator 22; and then the air enters the
cleaner main body 10. This air passes through the cleaner main body and is
exhausted to the outside.
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As seen from Figure 2, the cyclone type dirt separator 22 is comprised of a
dirt separating section 26, a dirt collection chamber 28, and a grip section
30.
The dirt separating section 26 includes an exhaust tube 32, a suction intake
tube 34, a spiral flow passage 38 and a spiral flow compartment 40. The
exhaust
tube 32 is, at its end, connected to the flexible tube 18; and this exhaust
tube 32
extends downward and is bent at its intermediate point to take a substantially
shallow V shape when viewed from the side as seen from Figure 2. The suction
intake tube 34 is disposed parallel to and on a different axis than the lower
part of
the exhaust tube 32, and the lower end of the suction intake tube 34 is
connected
to the extension tube 20. The spiral flow passage 38 is provided so as to
communicate with the upper end of the suction intake tube 34 and is led to the
outer circumference of the exhaust tube 32 so that the suction air is put in a
spiral
flow 36 (see Figure 3). The spiral flow compartment 40 separates dirt from the
suction air by means of the spiral flow 36 of the air. The exhaust tube 32 is
disposed in substantially coaxial with the central axis of the rotation of the
spiral
flow 36.
As shown in Figure 5, the spiral flow passage 38 is formed by being
surrounded by a partition wall 38a that constitutes the lower wall of the
spiral flow
passage 38 which forms a partition with the spiral flow compartment 40, a flow
passage opening 38b that is formed in this partition wall 38a, an inclined
wall 38c
that constitutes the upper wall of the spiral flow passage 38, a circular arc
form
outer circumferential wall 38d, and an inner circumferential wall 38e. The
flow
passage opening 38b is formed by cutting away the partition wall 38a for the
length L in the circumferential direction. The inner circumferential wall 38e
is
formed by the outer circumferential surface of the exhaust tube 32. The
upstream
side of the inclined wall 38c (the upstream side being the part located on the
suction intake tube 34 side) is connected to the upper wall of the suction
intake
tube 34, and the downstream side (which is the portion located on the
partition
wall 38a side) is connected to the rear edge 38f (which is on the downstream
side
in the spiral direction) of the opening 38b.
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The exhaust tube 32 is formed, on its circumferential wall, with numerous
exhaust openings 42 (see Figure 6) so that the exhaust openings 42 face the
spiral flow compartment 40. Each of the exhaust openings 42 is in a slit-form
having longer longitudinal sides in the longitudinal direction of the exhaust
tube 32
than the width in the circumferential direction. Thus, the exhaust opening 42
is,
for instance, approximately 20 mm long and approximately 6 mm wide. These
exhaust openings 42 are provided in two (upper and lower) stages in the
longitudinal direction of the exhaust tube 32, and they prevent large pieces
of
debris such as paper scraps or the like from being sucked into the exhaust
tube
32. The lower end 32a of the exhaust tube 32 is closed, and a baffling plate
44
that extends substantially in the form of a cone is disposed on this lower end
of
the exhaust tube 32. In the shown embodiment, the baffling plate 44 has a
substantially circular (reversed) conical shape so that the diameter gradually
increases toward its lower edge.
With the structure described above, air or dirty air is sucked in through the
suction fitting (suction brush) 24 and rapidly flows through the extension
tube 20
and into the suction intake tube 34 of the separator 22. Then, the air enters
the
spiral flow passage 38, flows along the curved outer and inner circumferential
walls 38d and 38e and hits the inclined wall 38c, so that the air, while being
rotating, flows downward into the spiral flow compartment 40 through the flow
passage opening 38b, thus forming a spiral flow 36 or "cyclone." The spiral
flow
36, particularly the portion of the air which is in the vicinity of the center
of the
spiral flow 36, enters the exhaust tube 32 through the exhaust openings 42 of
the
exhaust tube 32 so that large pieces of dirt in the air are caught by the
striped
pattern portions between the exhaust openings 42 and thus separated and
removed from the spiral flow 36, and the air without large pieces of dirt
eventually
flows into the cleaner main body 10 through the flexible tube 18.
The dirt collection chamber 28 has a shape of a substantially artillery shell
in which the upper end is open and the lower part shows a gradual and smooth
decrease in diameter. The dirt collection chamber 28 is, at its upper end,
attached
to the dirt separating section 26 in a coaxial relation with the exhaust tube
32, and
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the dirt collection chamber 28 is detachable with reference to the dirt
separating
section 26.
The spiral flow compartment 40 is provided in coaxial with the exhaust tube
32 between the exhaust tube 32 and the upper part of the dirt collection
chamber
28.
The diameter of the baffling plate 44 is set so that air is allowed to flow
between the baffling plate 44 and the inside surface of the dirt collection
chamber
28, so that the spiral flow 36 is prevented from flowing around beneath the
baffling
plate 44 and so that a gap that suppresses any back flow of dirt is formed.
The dirt collection chamber 28 is provided so that the inside bottom surface
46 is takes a curved surface that has a smooth decrease in diameter in the
downward direction. A recessed portion 48 that sinks downward is formed in the
center of this inside bottom surface 46 of the dirt collection chamber 28. The
recessed portion 48 is in a shape of a cylinder with a closed bottom, and the
diameter of this recessed portion is approximately 1/2 to 1l3 of the diameter
of the
dirt collection chamber 28. More specifically, the diameter of this recessed
portion
48 is approximately 1/2 to 1/3 of the diameter of the approximately the
vertically
central portion of the dirt collection chamber 28 which is substantially at
the height
of the baffling plate 44. As best seen from Figure 3, the central axis of the
recessed portion 48 is set on the central axis A of the exhaust tube 32, thus
being
on the axis of the rotation of the spiral flow 36.
The curved surface of the inside bottom surface 46 of the dirt collection
chamber 28 and the inside surface in the vicinity of the opening or of the
opening
edge 48a of the recessed portion 48 are formed so that they are not smoothly
continuous (or contiguous). In other word, as best seen from Figure 3, the
portion
where the inside bottom surface 46 of the dirt collection chamber 28 and the
opening or the opening edge 48a of the recessed portion 48 abut each other
with
an obtuse-angle and thus takes an obtuse-angle edge form surface or a step
form
surface. Since this abutting surface is thus a surface that is bent in a
discontinuous form, edge form or step form from the inside bottom surface 46
to
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the recessed portion 48, even if the spiral flow 36 drops down along the
inside
bottom surface 46, this spiral flow is blocked by the opening edge 48a of the
recessed portion 48, and dirt that has dropped into the recessed portion 48 is
not
entrained by the spiral flow. Furthermore, dirt that drops into the dirt
collection
chamber 28 is prevented from being entrained since such dirt dropping into the
dirt collection chamber 28 is entangled with dirt that has previously been
dropped
in the bottom of the dirt collection chamber 28.
The dirt collection chamber 28 is detachable. In other words, as shown in
Figures 1 and 2, the hook 50 provided in the vicinity of the lower end of the
suction intake tube 34 is provided so that it is engaged with and disengaged
from
the outside of the recessed portion 48 positioned at the lower end of the dirt
collection chamber 28. When the dirt collection chamber 28 is set on the
suction
intake tube 34 as shown in Figures 2 and 3, the dirt collection chamber 28 is
fastened in place by this hook 50. When dirt that has accumulated inside the
dirt
collection chamber 28 is to be discarded, the hook 50 is disengaged from the
recessed portion 48, the dirt collection chamber 28 is removed from the
suction
intake tube 34, and the dirt inside the recessed portion 48 is discharged.
While the invention has been described in terms of various preferred
embodiments, the skilled artisan will appreciate the various modifications,
substitutions, and changes which may be made without departing from the spirit
hereof. The descriptions of the subject matter in this disclosure are
illustrative of
the invention and are not intended to be construed as limitations upon the
scope
of the invention.
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