Note: Descriptions are shown in the official language in which they were submitted.
CA 02272493 1999-OS-20
KITCHEN WASTE COMPOSTER
FIELD OF THE INVENTION
This invention relates to a composter for kitchen waste and is particularly
directed to a space-saving configuration of the container into which the waste
is
introduced.
BACKGROUND OF THE INVENTION
While the art of composting has been practiced for many years, the means
provided to practice composting inside the home have not advanced to any
appreciable
extent. Commonly, home-owners will dispose of kitchen scraps into a bucket or
other
container which may be provided with a lid. Less frequently, special purpose
containers
fitted with activated carbon odour absorption means are used. The bucket is
periodically
emptied into a garden composter where the waste is left in a heap to
decompose. If the
home-owner is keen, the compost heap will be turned at regular intervals and
appropriate
activators will be added to the heap to promote decomposition.
Characteristically, the garden composter is located in a remote area of the
yard,
where it will be hidden from view. As a result, journeys to empty the bucket
from the
kitchen become an unwelcome chore, particularly in the winter in areas
enjoying colder
climates.
An object of this invention is to provide a composter which will facilitate
composting of kitchen waste inside the home. One of the challenges is to
provide a
container having sufficient capacity for decomposing the waste while occupying
a
minimum of space.
-1-
CA 02272493 1999-OS-20
SUMMARY OF THE INVENTION
In accordance with this invention, there is provided a composter adapted to
receive kitchen waste comprising vegetable matter. The composter is
characterized by an
outer drum having an axis for rotation which is disposed horizontally for
rotation inside
an outer housing. The outer drum and the housing have respective waste inlet
means
which are in communication with each other for receiving waste so that waste
which is
introduced into the housing is received inside the outer drum. An inner drum
having an
axis for rotation which is disposed horizontally for rotation of the inner
drum is disposed
with a first end wall thereof inside the outer drum and spaced from a closed
end wall of
the outer drum. Waste outlet means formed in a second end wall of the inner
drum and
spaced from the first end wall is adapted to discharge decomposing waste
through an open
end wall of the outer drum.
In addition, the outer drum has liquid outlet means formed in a side wall
remote
from the waste inlet means and a liquid drain tray is disposed beneath the
liquid outlet
means and is adapted to be removed from the housing. A compost finishing
drawer is
adapted to receive decomposing waste exiting from the waste outlet means and
is also
adapted to be removed from the housing. Rotation means are provided for
turning the
outer drum and also for turning the inner drum. In use, waste received inside
the outer
drum is mixed and enters waste inlet means of the inner drum when a minimum
load has
been exceeded. Continued rotation of the inner drum causes the decomposing
waste to
mix further and to eventually leave the waste outlet means for final
decomposition in the
compost finishing drawer.
-2-
CA 02272493 1999-OS-20
In a preferred embodiment of the invention, the outer drum comprises an outer
cylindrical wall, a closed end wall and an open end wall defining an opening
which
receives the inner drum, the inner drum comprising an inner sleeve having an
outer
cylindrical wall and an open end wall formed integrally with the open end wall
of the
outer drum, the open end wall defining the waste inlet means for the inner
drum. Most
preferably, the inner drum additionally comprises an outer sleeve having an
outer
cylindrical wall and an open end wall defining the waste outlet means, the
outer sleeve
and the inner sleeve together defining a side wall for the inner drum.
BRIEF DESCRIPTION OF THE DRA~L1INGS
In order that the invention may be more clearly understood, a preferred
embodiment is described below with reference to the accompanying drawings, in
which:
Fig. 1 is a perspective view from the front and to one side of a kitchen waste
composter in accordance with the invention with a liquid drain tray and a
compost
finishing drawer removed from the composter;
Fig. 2 is a similar view to Fig. 1 from the other side of the composter;
Fig. 3 is a similar view to Fig. 2 (drawn to a larger scale) and partially cut
away to show
an outer drum and an inner drum located inside an outer housing of the
composter;
Fig. 4 is a sectional view drawn on line 4-4 of Fig. 3;
Fig. 5 is a schematic sectional side view drawn on line 5-5 of Fig. 2;
Fig. 6 is a schematic sectional front view drawn on line 6-6 of Fig. 2;
Fig. 7 is an exploded view showing the assembly of the inner drum and outer
drum and
a boss formed in the outer housing for supporting the inner drum during
rotation thereof;
-3-
CA 02272493 1999-OS-20
and
Fig. 8 is a similar view to Fig. 1 showing an alternative embodiment of the
invention
which includes a motor drive assembly.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A kitchen waste composter made in accordance with the invention is generally
indicated in Fig. 1 by reference numeral 20. The composter 20 comprises an
outer
housing 22 which is rotation-moulded from synthetic plastic material and has a
wall
thickness of 5 mm selected to provide sufficient rigidity to be self
supporting and to
additionally provide structural support for the drum components rotatably
supported
inside the housing, as described further below. It will be seen that planar
vertical surfaces
of the housing are formed with a matrix of ridges 24 in order to provide
additional
structural support and reinforcement.
VLlhile the housing has a generally cuboid configuration, it will be observed
that
selected portions have a stepped profile in order to optimize the use of space
so as to
accommodate a hand crank 27 disposed on a side panel 26 and fan assembly 29
disposed
on a rear panel 28.
A front panel 30 for the housing has three openings 32, 34, 36 formed therein.
The opening 32 is formed adjacent a top panel 38 and has a hinged door 40
defining a
chute or waste inlet means through which kitchen waste comprising vegetable
matter is
introduced into the composter 20. The openings 34, 36 are formed adjacent to
each other
at the bottom of the front panel 30, opening 34 accommodating a shallow liquid
drain
tray 42 and opening 36 accommodating a deep compost finishing drawer 44.
-4-
CA 02272493 1999-OS-20
As will be seen in Figs. 3 to 7, an outer drum 46 having an axis for rotation
which is disposed horizontally for rotation of the outer drum inside the
housing 22
comprises an outer cylindrical wall 48, a closed end wall 50 and an open end
wall 52
defining an opening adapted to receive an inner drum 54.
U
The inner drum 54 is adapted to rotate with the outer drum on the same
horizontal axis for rotation. The inner drum 54 comprises an inner sleeve
having an
outer cylindrical wall 56 and an open end wall 58 formed integrally with the
open end
wall 52 of the outer drum 46. An outer sleeve having an outer cylindrical wall
60 and
an open end wall 62 is joined to the inner sleeve to define the inner drum 54,
the outer
cylindrical walls 56, 60 together defining a side wall for the inner drum 54
(Figs. 6, 7).
It will be appreciated that the inner drum 54 is partially disposed inside the
outer drum
46 so that the open end wall 58 is spaced from the closed end wall 50.
The outer drum 46 has waste inlet means in the form of an opening 64 (Fig. 5)
formed in the outer cylindrical wall 46 and which may be brought into
communication
with the chute 40 defining the waste inlet means for the housing 22 upon
rotation of the
drum. The opening 64 is normally closed during rotation of the outer drum 46
indicated
by directional arrow 66 in Fig. 5 by means of a hinged flap 68. It will be
appreciated that
the flap 68 hangs vertically inside of the outer drum 46 so as to liberate the
opening 64
when it is brought into alignment with the chute 40. Kitchen waste which is
introduced
into the housing 22 is thus received inside the outer drum 46.
Alignment of the opening 64 with the chute 40 is executed with the help of
stop
means 69 comprising a flexible guide plate 71 anchored at one end of the
housing 22 and
biased toward engagement with the surface of the outer drum 46. A
complementary
U
-5-
CA 02272493 1999-OS-20
recess 73 formed in the surface of the outer drum 46 receives the guide plate
71 and is
engaged by the guide plate 71 if the outer drum 46 is rotated in the opposite
direction.
It will be understood that the stop means 69 do not operate to obstruct any
rotational
movement of the outer drum 46 in the direction of rotation 66 and that an
audible "clap"
will be heard when the guide plate 71 falls from the surface of the outer drum
46 to the
recess 73, thereby alerting the user that the required openings are in
alignment.
As will be apparent from Fig. 5, waste material 94 received in the outer drum
46 will come to rest inside the drum to form a heap which is deeper at the
back of the
housing 22 (drawn to the left in Fig. 5) and is shallower at the front of the
housing
immediately beneath the opening 64. In this way, more space is provided close
to the
chute 40 where bulky fresh waste material is received into the composter.
A number of ribs 77 are formed on the interior surface of the outer drum 46 to
assist in lifting waste as the drum rotates.
A second opening 70 is formed in the outer cylindrical wall 56 of the outer
drum 46 remote from the waste inlet opening 64 and positioned so as to lie at
the bottom
of the outer drum 46 when the waste inlet openings 64 and 32 are brought into
alignment. The opening 70 is covered with a mesh 72 to define liquid outlet
means
whereby liquid will drain from the outer drum 46 into the liquid drain tray
42.
A vent defined by perforations 75 is formed in the outer drum 46 and is
diametrically opposite from the opening 70. VTlhile composting of vegetable
waste matter
is odourless with proper aeration of the waste, the composter 20 includes a
fan assembly
29 which is in open communication with the interior of the housing 22. The
discharge
air from the fan assembly 29 is optionally directed through an outlet pipe 31
(drawn in
-6-
CA 02272493 1999-OS-20
chain-dotted outline in Fig. 3) which is installed to vent any decomposition
gases through
an exterior wall of the kitchen. Alternatively, the discharge air from the fan
assembly 29
is directed to an activated carbon filter 33 (drawn as a block in chain-dotted
outline in Fig.
3) which may be replaced periodically, as the need arises.
The closed end wall 50 of the outer drum 46 is inwardly deformed on its
horizontal axis to define a bushing 74 (Figs. 2, 6) that receives a first boss
76 formed in
a left side panel 78 of the housing 22. The boss 76 is adapted to support the
outer drum
46 during rotation of the drum.
The drum is similarly supported at the other end by the open end wall 62 of
the
inner drum which forms a bushing 80 (Figs. 6, 7) rotatably received inside a
second boss
82 defined by an inwardly-directed cylinder integrally formed with the right
side panel
26 of the housing 22. Conveniently, the second boss 82 is closed at its outer
end by a
disc 84 which, in use, is cut from the open end wall 58 of the inner drum 54
to define a
waste inlet means 86 to the inner drum.
It will be appreciated that, when a predetermined volume of waste has
accumulated in the outer drum 46, continued rotation of the outer drum 46 will
cause
such waste to enter the inner drum 54 through the waste inlet means 86. The
quantity
of waste which is admitted to the inner drum from the outer drum is, in part,
determined
by the relative position of the inner drum to the outer drum.
The outer drum has a gear rim 88 (Fig. 3) formed in the outer cylindrical wall
48 adjacent to the closed end wall 50. A pinion wheel 90 is disposed outside
of the outer
drum to cooperate with the gear rim 88 and is supported on a drive shaft 92 of
which the
ends are likewise supported by the left and right side panels 78, 26 of the
housing 22.
_7_
CA 02272493 1999-OS-20
The hand crank 27 is turned to rotate the pinion wheel 90 which, in turn,
drives the
outer drum 46 for rotation inside the housing 22. Alternatively, the drive
shaft 92 may
be operatively connected to a motor drive assembly 93 shown schematically in
Fig. 8.
It will be appreciated that rotation of the outer drum 46 causes the inner
drum
54 to rotate with it and to thereby move any decomposing waste indicated by
reference
numeral 94 so that it exits through waste outlet means 80 in the open end wall
62.
Additional drainage of excess liquid is afforded by liquid outlet means 96
(Fig. 7) formed
in the outer cylindrical wall 60. Decomposing waste which leaves the inner
drum 54 is
discharged for final decomposition in the compost finishing drawer 44 through
an opening
98 formed in the second boss 80.
The flow of waste material thus proceeds from the chute 40 into the housing 22
as indicated by directional arrow 100 (Fig. 5) where it is discharged into the
outer housing
46 as indicated by directional arrow 102. The waste 92 settles at the bottom
of the outer
drum 46 where excess liquid is drained through opening 70 into the liquid
drain tray 42.
When the volume of waste material reaches the height of the inner drum 54, a
significant
proportion of the waste has been in residence in the outer drum 46 for
sufficient length
of time to begin decomposition. It will be understood that heavier waste which
requires
a longer residence time to decompose travels more slowly through the composter
while
lighter waste material, which generally requires a shorter residence time
tends to remain
on top of the heap and travels more quickly through the composter.
An overflow of such decomposed waste material is received into the inner drum
54 where the residence time is still further prolonged until it exits as
indicated by
directional arrows 104 (Fig. 6). Still further decomposition takes place in
the finishing
_g_
CA 02272493 1999-OS-20
drawer 44, which is disposed to receive the decomposed waste emerging from the
inner
drum and which occupies a significant height inside the housing so as to
maximize its
capacity.
It will thus be appreciated that the configuration of the outer drum 46 with
the
inner drum 54 disposed inside, allows for a two-stage decomposition of waste
matter,
thereby maximizing the capacity of the composter while occupying a minimum of
space
which is customarily at a premium in the kitchen environment.
It will be further appreciated that several variations may be made to the
above
described embodiment within the scope of the appended claims. In particular,
it will be
noted that the inner drum may be formed as a discrete piece of the composter
and that
its axis of rotation may be spaced from, and parallel to, the axis of rotation
of the outer
drum. In this way, the inner drum may be rotated independently of the outer
drum to
thereby regulate the flow of waste material through the composter.
05171500.APP
-9-
