Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a mobile compost bin in
a closed container form.
In modern waste management planning, such compost bins
fulfill an important function with respec-t to the necessity of
utili~ing fermentable organic waste. The container-shaped (cube-
shaped) cons-truction of these compost bins, permitting easy hand-
ling of the compost material, is of particular advantage since
these bins can be stacked not only if required for the period of
the decomposition process and thus -take up Little space, but can
also be moved and emptied by means of various lifting and trans-
port systems (e.g. dump truck, crane runway, bridge crane, con-
tainer crane, etc.).
Compost bins of a compost construction, which is known
from WLB 5 (1989~, page 53, are loaded through a loading hatch in
the top of the container, the hatch being fastened on ore side
with hinges, and are unloaded through a swing-out unloading hatch
on a narrow side of the container.
The connecting pieces for supplying and carrying off the
air required for rapid composting are also arranged in the area of
the unloading hatch. The bottom of the compost bin is designed as
a double bottom, the upper part of which is a continuous bottom
plate (perforated plate) with circular air holes. This perforated
plate is tightly connected to the container. The edges of the air
holes are sharp. The hollow space below the perforated plate
communicates with one of the air connecting pieces for supplying
or carrying off the air.
When air is circulated from top to bottom, condensation
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water, and possiDly also seepage water, collects on the lower
bottom plate in the hollow space below -the perforated plate. This
condensation water gets into the pipe of the air hole and must be
removed from there, necessitating appropriate manual intervention.
The permanently welded perforated plate constitutes a further dis-
advantage of the known compost bins since replacement in the event
of repair is very expensive. Furthermore, problems occasion ally
arise when emptying the container, which can as such be carried
out very simply by tilting the container, for example by means of
a container crane, whereby the compost slides out of the unloading
hatch. In this connection it can happen that the compost sticks
to tne perforated plate and to the side walls because the
container cannot be tilted far enough. Inclination to the hori-
zontal is often restricted to about 45. Moreover, cleaning a
compost bin after it is emptied in order to prepare it for the
next use is occasionally complicated. Cleaning is carried out by
rinsing the tilted container witn water. Removal, if required of
the compost scrap that fell into the holLow space of the double
bottom is difficult.
Finally, it is also a disadvantage that air cannot flow
through the perforated plate at points at which this plate is
placed on cross giraers to guarantee an adequate load-carrying
capacity and to prevent buckling, since the air hoLes are covered
by the cross girders.
It is therefore the object of the present invention to
improve a compost bin such that these disadvantages are to a large
extent avoided. In particular, it should be easy to e~pty and
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clean the compost bin.
The invention provides a mobile compost bin in a closed
container form comprising connections for supplying and carrying
off air for the decomposition process, a double bottom formed from
a continuous lower bottom plate and a perforated plate arranged
above it, a drainage pipe from the hollow space of the double
bottom, at least one loading hatch in the top of the compost bin
and as at least one unloading hatch in a side wall of this bin,
said perforated plate being configured from a plurality of
inverted U-profiles having webs arranged in closely adjacent co-
planar disposition, said web~ including air holes therein and said
U-profiles having longitudinal axes extending towards the unload-
ing hatch and having flanges that are loosely supported by on
cross girders in said double bottom (3).
The present invention will be described in greater de-
tail herebelow on the basis of the compost bin illustrated in the
accompanying drawings wherein:
Figure 1 is a side view of a compost bin,
Figure 2 is a top view of a perforated plate,
Figure 3 is a longitudinal section through the compost
bin,
Figure 4 is a cross-section through the compost bin,
Figure 5 is an enlarged top view of a perforated
plate/U-profile,
Figure 6 is a cross-section through a perforated plate/
~-profile, and
Figure 7 is a partial sec-tion in the area of the unload-
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ing 'hatch.
The mobile compost bin illustrated in Figure 1 is con-
structed of torsion-resistant section steel/steel plate and is
provided all around wit`h a 40 mm thick insulation with galvanized
sheet steel jacket (not shown) for thermal and low temperature
insulation. Rollers are attached to the bottom 3 so that it can
be transported as a roll-off container, for example by means of a
winch truck. The rollers can of course be dispensed with for
crane transport with a spreader. As can be seen in Figures 3 and
4, the bottom 3 is designed as a double 'bottom, i.e. a continuous
bottom plate 4 is provided at the bottom and a perforated plate 5
is arranyed at a distance above it. A hollow space, through which
the air required for rapid composting can be supplied or carried
off, is formed between the bottom plate 4 and the perforated plate
5. This hollow space is therefore in communication with the con-
nection piece 2 for supplying or carrying off air. A second air
connection piece, not illustrated, is arranged at the same level
as the connection piece 2 and communicates with the upper part of
the container interior. T'he compost bin 1 i5 loaded through a
loading hatch 6 that can be raised (Figure 4) and is unloaded
through a swing-out unloading hatch 7 (Figure I). Manual or motor
operated locking mechanisms are provided to open and hermetically
seal the hatches 6, 7.
As is iLlustrated in Figures 2, 3 and 4, the perforated
plate 5 comprises a plurality of U-profiles 8 whic'h are arranged
close beside one another and are loosely supported on cross gird-
ers 12. These cross girder~ 12 are permanently welded at a dis-
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tance from the lower 'bottom plate 4 by means of supports 13. As
is indicated in Figure 2 and as can be clearly seen in Figures 5
and 6, the U-profiles 8 have numerous air holes 11 in their centre
webs 9 for aeration of the organic material to be composted. T'he
flanges 10 (Figure 7) of the U-profiles 8 are supported on the
cross girders 12 and t'he longitudinal axis of these U-profiles
points in the direction of t'he unloading hatch 7.
A number of advantages are achieved by means of this
arrangement. On the one hand, air can flow to the full extent
through the centre webs 9 via the air holes ll, i.e. there are no
points at which the air holes ll are blocked by the support of
a cross girder 12, as is the case with the known compost bin with
a continuous perforated plate. Therefore, more effective and more
uniform composting is possible with the U-profiles 8 arranged
endwise. On the ot'ner hand, the loose support of the U-profiles
allows the hollow space in the double bottom 3 to be uncovered
quickly without any connections having to be loosened for this
purpose. Cleaning this area of the compost bin 1 is thus simpli-
fied quite considerably and it is also possible to replace the
U~profiles without difficulty. Because the u-profiles 8 can be
easily replaced, they are advisably manufactured as expendable
parts from inexpensive structural steel. Thus, no high-grade,
corrosion-proof materials need be used. A further advantage
emerges from the shape of the U-profiles 8 since they have a high
static strength (flexural strength) even with a low wall thickness
and thus require comparatively little support through the cross
girders. Moreover, the orientation of the longitudinal axis of
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the u-profiles 8 makes it easy for the compost to slide out
smoo-thly when emptying the compost bin 1.
The U-profiles 8 are advisably secured separately so
that they cannot likewise slide out when emptying the bin. No
screw or clamping connections or the like are necessary for this
purpose; rather, as can be seen from Figure 7, it is sufficient to
provide an L-shaped cross girder 15 on which the U-profiles 8 abut
in the area of the unloading hatch 7.
A furt'ner advantageous embodiment lies in providing the
air holes 11 with rounded, preferably downwardly (to the hollow
space of the double bot-tom 3) flanged edges 16 (Figure 6) so that
the sliding surface on the perforated plate 5 is as smooth as
possible. Holes with sharp edges impede the emptying process.
A further improvement in the emptying of the bin results
when the air holes 11 are designed as elongated holes (Figure 5),
their longitudinal axis extending in the direction of the longitu-
dinal axis of the profile 8. Elongated holes with a width of
about 8 - 10 mm and a length of 20 - 25 mm have proven advanta-
geous. Moreover, it is oftentimes advantageous for the perforated
plate 5 to slope towards the unloading hatch 7. However, this
incline should be less than 5, preferably less than 3 (in parti-
cular, about 1.5~) to the horizontal so that the useful volume of
the compost bin 1 is not reduced too much. The idea of this
incline is that sufficient inclination of the perforated plate 5
can still be achieved when the compost bin 1 is tilted if the bin
1 itself cannot as such be tilted far enough. The degree of
incl:ne that is otherwise missing is often only in the range of 1
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to 2.
In a further advantageous embodiment of the present
invention the side walLs 17, 18 on the long side of the compost
bin 1 are slightly divergent in the direction towards the unload-
ing hatch 7, that is their distance from one another increases.
This likewise simplifies emptying of the compost bin 1. To this
end, an incline to the longitudinal axis of the compost bin of
less than 1, in particular of about 0.5. is often times suffi-
cient.
To facilitate removal of seepage water and condensation
water from the compost bin 1, it is recommended that a drainage
channel 14 (Figure 3, 7), which ends in a drain connection piece
(not illustrated), be provided in the lower bottom plate 4 of the
double bottom 3 at an outer surface of the compost bin 1, prefer-
ably in the area of the unloading hatch 7. In order to collect
the water in the channel 14, the lower bottom plate 4 need not be
inclined compared to the outer support points of the compost bin 1
that is set down since the compost bin can from -the start be set
down on a site with a suitable incline.
Since the cross girders in a further advantageous
embodiment of the present invention are merely supported on the
supports 13 on the bottom plate 4 of the compost bin 1, the water
can flow virtually unimpeded in the channel 14. The drain connec-
tion pieces are advisably equipped with a 3-way valve so that a
drainage line from the, for example siphon-Like, pipe connection
for supplying and carrying off air into or from the upper region
of the compost bin 1 can also be connected to the drain connection
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pieces without thereby reducing the circulation of air, since the
air can directly enter the siphon of the exhaust air duct via the
pipe connection of the channel 14, for example when compressed air
is supplied to the hollow space of the double bottom 3. In such a
case, the connection of the channel 14 would be blocked by the
3-way valve and only the drainage connection for the siphon of the
exhaust air duct 2 would be open. In any case, no condensate
would precipitate in the hollow space of the double bottom 3 with
air supplied in this direction.
The compost bin l designed in accordance with the pres-
ent invention per,nits, particularly by means of its novel perfor-
ated plate, empt~ing and cleaning to be carried out without diffi-
culty and, in the event of repair, also permits simple replacement
of damaged parts of the perforated plate. Since the air holes 11
can be manufactured from the start with flanged edyes by means of
an appropriate press tool, manufacture of the U-profiles does not
involve great expense.
