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|United States Patent Application
December 27, 2007
Rotary Drum for the Aerobic Heating of Pourable Solids
The invention concerns a rotary drum (1), in which the hygienic status of
separated, pourable cow manure solids (3) is modified by aerobic heating
such that the solids can be re-used as bedding in cowsheds. The aim of
the invention is that of achieving a high charge level of the drum (1),
which lies horizontally for incorporation in an insulated container (2),
with a filling level of 60-70% being achieved. According to the
invention, the loaded solid (3) is kept in a chamber (4,8) and is passed
to the drum (1) only when there is no solid surrounding the chamber
(4,8). An important element is a flap (4,9) of the chamber (4,8), which
opens and closes in this area only. If there is solid material on the
outside of the flap, then the flap is prevented from opening (4,9).
Eichler; Dietrich; (Grosskarolinenfeld, DE)
EDWARDS ANGELL PALMER & DODGE LLP
P.O. BOX 55874
November 8, 2005|
November 8, 2005|
May 14, 2007|
|Current U.S. Class:
|Class at Publication:
||F26B 11/06 20060101 F26B011/06|
Foreign Application Data
|Nov 16, 2004||DE||10 2004 051 802.5|
|May 20, 2005||DE||10 2005 023 258.2|
1. A rotary drum for aerobic heating of a pourable solid by constantly
revolving a still damp solid and supplying fresh air, wherein the solid
at the inlet side of the rotary drum enters an antechamber through a
funnel and a central opening, said antechamber being bounded by an outer
side wall and an inner side wall located behind and spaced from the outer
side wall, wherein an inlet channel is provided between these side walls
on the wall of the rotary drum, which picks up the solid in the direction
of rotation, wherein, in the inner side wall, there is an opening which
leads to a chamber located in the interior of the drum, said opening is
covered by a flap which opens into the interior of the drum and only
opens when the chamber is in a portion of the rotary drum wherein no
pourable solid is present and closes again before it re-enters the solid,
and wherein the fresh air is sucked in through a ring-shaped discharge
weir for the pourable solids and is sucked out through a ventilating
means located in the vicinity of the filling device and an axially
2. The rotary drum according to claim 1, wherein several filler devices
for charging the pourable solid incorporating correspondingly effective
flaps are provided around the periphery of the drum.
3. The rotary drum according to claim 1, wherein blades directly attached
to the casing of the drum advance the pourable solid towards the
discharge side whereat guide plates effective in opposite direction are
fixed at a distance of half a radius from the casing.
4. The rotary drum according to claim 1, wherein there is a fixed
ventilation pipe located in the vicinity of the inlet side for the solid
comprising a radial pipe portion leading into the solid-free portion of
the drum, a downwardly directed elbow portion and a succeeding axial pipe
 The invention relates to a rotary drum in which the hygienic status
of pourable solids separated from liquid cattle manure is modified by
aerobic heating in such a manner that said solids can be reused as
bedding in cattle sheds.
 The object of the invention is to obtain a high loading factor
amounting to 60-70% filling of the drum which is located horizontally for
installation in an insulated container.
 In accordance with the invention, the loaded solid is kept in a
chamber and is only transferred to the drum when there is no solid
surrounding the chamber.
 The crucial element is a flap of the chamber which only opens and
closes in this area. If there is any solid resting on the outside of the
flap then opening of the flap is prevented.
 In order to enable ventilation to be effected despite the filling
process taking place along the axis, supply air is sucked in through the
ring-shaped weir required for the discharge of the solid in a direction
opposed to that in which the solid is being advanced and is then sucked
out through a fixed pipeline at the inlet end.
FIELD OF APPLICATION
 The subject matter of the invention is a rotary drum in which germs
can be reduced and water removed by means of an aerobic heating process.
The field of application is mainly in the treatment of pourable solids
separated from liquid cattle manure. Hereby, the object is to modify the
hygienic status of the solid in such a way that it can be reused as
bedding in cattle sheds.
TYPICAL CHARACTERISTICS OF KNOWN TECHNICAL SOLUTIONS
 Rotary drums for the treatment of materials in different ways have
been known for a long time. The pourable solids are introduced through
funnels as is disclosed in specifications DE 26 34 220 C2 and U.S. Pat.
No. 4,168,915. Consequently, without special adapters in the loading area
thereof, it is only possible to fill a horizontal drum to a capacity of
approximately 35% taken with respect to the diameter of the drum.
 In order to get quantities above this into the drum, it is
necessary to have blades, baffle plates and guide plates or screw
conveyers of various designs installed in the drum. A plurality of
similar built-in features are provided for this purpose in patent
specification DE 270 86 98.
 In order to enable the drum to be ventilated by means of a suction
draught from the supply to the discharge side, a spiral channel using the
solid being discharged as a closure member is arranged at the discharge
side in DE-PA 199 28 883,6. This solution requires precise dosage of the
quantities being fed-in and discharged. The drum would otherwise be
either overfilled or emptied. In this publication, the drum is
accommodated in a container. This arrangement has the advantage that the
heat from the biological process and the heated air from a drive motor
can be distributed uniformly over the outer casing of the drum.
THE OBJECT OF THE INVENTION
 An object of the invention is to obtain a filling degree of 60-70%
for a horizontal drum that is be installed in a container utilising a
simple device. Furthermore, just as much solid as is being supplied to
the filling side should always be automatically leaving the drum.
 The supply of air necessary for the micro-biological process should
be designed in such a way that, by using the counter-flow principle, the
treated material comes into contact with cold fresh air whereas the
material in the vicinity of the supply side comes into contact with used
FEATURES OF THE INVENTION
 According to the invention, the pourable solid that is to be fed-in
is kept in a chamber and is only delivered in that area thereof in which
no solid is present. The crucial element is a flap provided in the
chamber which opens only within the area and closes. If any solid is
resting on the outside thereof, the flap cannot open.
 For the purposes of carrying out this operation, the pourable solid
at the inlet side of the rotary drum passes through a funnel and a
central opening into an antechamber bounded by an outer side wall of the
drum and an inner side wall located behind and spaced from the outer side
wall. An inlet channel provided on the wall of the drum and located
between these walls picks up the solid in the direction of rotation. An
opening in the inner side wall leads to a release chamber located in the
interior of the drum.
 The release chamber is covered by a flap which opens into the
interior of the drum but which does not open until, due to the rotation
of the drum, the release chamber is in an area where there is no solid
present. In the course of further rotation, the flap closes again before
it re-enters the solid.
 Depending on the quantity of solid that is to be introduced,
several such devices for inserting the pourable solid can be located
around the periphery of the drum.
 Supply air is sucked in through a ring-shaped weir required for the
discharge of the solid in a direction opposed to that in which the solid
is being advanced. Sucking off the air is effected through a fixed
axially located pipeline which is extended radially into the solid-free
portion of the drum in the vicinity of the filling side for the solid. A
downwardly arranged elbow portion is attached here for preventing solids
from falling into the pipe. The suction pipe is fixed to the funnel. A
fan produces a negative pressure required for the movement of the air.
 FIG. 1 shows a longitudinal section through a rotary drum (1) which
is installed in an insulated container (2). Goods to be treated (3) are
introduced into the interior of the rotary drum (1) through a filling
device (4). The rotary drum (1) is set into rotation by a drive (5). The
pourable solid (6) is constantly moved toward the discharge side by
blades (7) attached to the surface of the drum. Guide plates (8)
effective in opposite direction are located in the vicinity of the
discharge side and are fixed at a distance of approximately half a radius
from the surface of the drum. They dam up the solid in front of the
ring-shaped discharge weir (9). In consequence, a large portion of the
drum volume remains filled with 65-75% solid. Only that much solid as is
supplied by way of the filling device (4) is discharged from the drum
through the discharge weir (9).
 The air flowing through the discharge weir (9) in a direction
counter to that of the flow of the solid, over the filling volume (6), is
sucked out of the system by means of a fan (13) through a fixed
ventilation pipe (11) and the following axial pipe (12). If necessary, a
filter system corresponding to the state of the art can be connected here
at the outlet side thereof.
 FIG. 2 is an axial section of the drum (1) showing the filling
device (4) at the intake side and the positions of the sections A-A and
B-B shown in the following figures. The damp solid that is to be
composted passes through the funnel (4.1) and the central opening (4.2)
and enters the antechamber (4.3) which is formed by the face wall (4.4)
and the inner side wall (4.5).
 In this embodiment, two oppositely located identical filler systems
are provided for feeding purposes.
 During rotation of the drum, the pourable solid is picked up by the
inlet channel (4.6) that is open in the direction of rotation, and is
carried into the rear portion of this channel during further rotation of
the drum. Here, there is an opening (4.7) in the inner side wall (4.5)
through which the solid enters the release chamber (4.8) in the course of
 At the appropriate side thereof, this chamber has a flap (4.9)
which will only open when the chamber reaches that portion of the drum in
which no solid is present so that the flap can only open here. A further
condition for the position of the flap (4.9) is that it closes before it
re-enters the solid and remains closed whilst in the solid.
 For the purposes of a better overview, the reference symbols are
only provided at a few locations of the following figures.
 FIGS. 3, 4 and 5 show the section A-A through the antechamber (4)
illustrated in FIG. 1. The drum is rotated through approximately
33.degree. in FIG. 4 and through a further 45.degree. in FIG. 5. In FIG.
3, the solid begins to flow into the inlet channel (4.6) in the lower
filler device. In the upper filler device, the process of emptying the
channel through the opening (4.7) is already completed. In FIG. 4, the
process of filling the inlet channel (4.6) is almost completed and the
solid is already entering the release chamber (4.8) represented by dashed
lines through the opening (4.7) in the inner side wall (4.5). In FIG. 5,
just so much solid as the release chamber (4.8) can accommodate now
slides through the opening (4.7) from the inlet channel (4.6).
 FIGS. 6, 7 and 8 show the section B-B represented in FIG. 2.
Hereby, the drum is likewise rotated through approximately 33.degree. in
FIG. 7 and through a further 45.degree. in FIG. 8. In FIG. 6, the flap
(4.9) of the release chamber (4.8) of the now upwardly located filler
device has just opened and the solid has slid down into the drum. The
flap of the filler device in the lower position is held in a closed
position by the solid abutting the flap.
 In FIG. 7, the flap (4.9) of the filler device now located in the
upper position has reached its largest opening angle and then begins to
close again under its own dead weight. In FIG. 8, the outpouring solid
begins to cover the already closed flap (4.9). In the oppositely located
filler device, the associated flap would open under its own dead weight
if there were no solid in the drum. However, it cannot open up because
the still immoveable solid is preventing this action. In consequence, its
contents are carried into the area in which the flap can reopen due to
the flow-off of the solid thereby enabling 60-70% filling of the drum.
 In this figure furthermore, the fixed ventilation pipe (11) is
shown together with its elbow portion which leads away from the
solid-free part of the drum.
* * * * *