|Title of Invention||
A DEVICE FOR TREATING PARTICULATE MATERIALS
|Abstract||An apparatus (10) for treating participate material has a proc- ess chamber (16) for receiving and treating the material. A bottom (18) is composed of a plurality of overlapping guide plates (22—24) which are placed one above the other and between which annular slots (25, 26) for process air to pass through are formed. An annular-gap nozzle (30) is arranged centrally in the bottom (18), the orifice (32) of this annular-gap nozzle (30) beihg designed in such a way that a planar spray pancake (44) which runs approximately parallel to the bottom plane can be sprayed. (Fig. 1)|
|Full Text||Apparatus for treating particulate material
The invention relates to an apparatus for treating particulate
material, having a process chamber which is intended for re-
ceiving and treating the material and has a bottom which is
composed of a plurality of overlapping guide plates which are
placed one above the other and between which annular slots are
formed, via which process air having an essentially horizontal
component motion directed radially outward can be introduced.
Such an apparatus has been disclosed, for example, by DE 102 48
Such known apparatuses serve to dry, granulate or coat particu-
late material. A gaseous medium, "process air", is introduced
into the process chamber via the bottom and enters the process
chamber in an approximately horizontally oriented manner
through the numerous slots between the overlapping guide
plates. Due to overlapping, annular guide plates, between which
numerous slots are formed, a flow of process air directed ra-
dially from inside to outside forms in the process chamber and
is deflected upward by the wall of the process chamber. The
material to be treated is entrained in the process, but falls
centrally downward on account of the gravitational force and
again strikes the air cushion of the process air. If a certain
extensive component is imposed on the process air, a toroidally
revolving swirl flow ring gradually forms.
If larger agglomerates are to be formed from powders as fine as
dust, that is to say if the material is to be granulated, a
sticky medium is sprayed toward the toroidal ring via nozzles.
In DE 102 48 116 B3 mentioned at the beginning, for example,
spray nozzles directed obliquely upward are inserted into the
wall of the container which encloses the process chamber.
During coating, a coating layer is to be applied as uniformly
as possible to a larger body already present, that is to say
said coating layer is to be sprayed on.
Various configurations of nozzles are known, the common feature
of which is that a usually liquid or also particulate treatment
substance is sprayed by means of spray air to form a fine mist.
To this end, it has become known, for example, to expel the
liquid under high pressure from a slot-shaped nozzle orifice
and to spray it through spray-air orifices, whether on one side
or on both sides of the liquid gap.
DE 102 32 863 Al has disclosed an atomizing nozzle which has
flow passages which are annular in cross section. Depending on
the spray angle and looping angle, radiate, conical or more or
less planar spray pancakes are produced. At a spray angle of
180° and a looping angle of 360°, a virtually planar spray
pancake is produced.
In this technology, which is widely used in the pharmaceutical
field of application, it is attempted to achieve a result which
is as uniform as possible, i.e. to achieve granulates with a
very narrow grain size distribution, and to achieve during the
coating a coating layer which is as uniform as possible, i.e.
in particular a coating layer of identical thickness, at all
particles of the charge which are contained in the apparatus. A
considerable problem consists in the fact that material parti-
cles which wander around in an uncontrolled manner and are
wetted with the moist and usually sticky spray liquid adhere to
one another to form unwanted agglomerates.
Therefore precisely defined flow conditions which permit an
optimum treatment result are desired in the toroidally rotating
material band. In particular, it is desired that, after the
spraying, the particles assume a flight path in which they move
away from one another where possible and not toward one another
in order to prevent undesirable agglomerates.
It is therefore the object of the present invention to provide
for an improvement in such apparatuses for the treatment of
particulate material to the effect that a harmonious sequence
of movement with an optimum treatment result can be achieved.
According to the invention, the object is achieved in that, in
an apparatus of the type mentioned at the beginning, an annu-
lar-gap nozzle is arranged centrally in the bottom, the orifice
of this annular-gap nozzle being designed in such a way that a
planar spray pancake which runs approximately parallel to the
bottom plane can be sprayed.
The combination of such an annular-gap nozzle with a bottom of
annular guide plates having a flow of process air directed from
inside to outside now leads surprisingly to an especially har-
monious guidance of air and material. The process air discharg-
ing through the annular slots forms an air cushion which glides
radially from inside to outside over the bottom and leads the
material to be treated radially outward into an increasingly
larger available space; the particles thus first of all move
away from one another.
The process air directed upward on the wall carries the mate-
rial particles along with it vertically upward. These material
particles separate from the process air flowing off, are moved
in a radially inwardly directed manner toward the center and,
on account of the gravitational force, fall downward approxi-
mately centrally in the center onto the cushion of process air
passing through the bottom. Due to the central provision of the
annular-gap nozzle with the planar spray pancake sprayed from
said annular-gap nozzle, the material falling down can be
sprayed uniformly and can then immediately be moved radially
outward in a radiated manner, that is to say the material par-
ticles can be moved away from one another. The material parti-
cles are therefore sprayed in a very specific manner by the
spray pancake when falling down, are cushioned by the process
air cushion and are moved radially outward. After leaving the
spray pancake, the further path directed horizontally radially
outward, with the subsequent movement rising vertically upward
and the movement returning again to the center, is available in
order to dry and accordingly solidify the sprayed particles by
means of the process air before they strike the spray pancake
again. Due to the 360° looping of the spray pancake, all the
material falling down centrally can be sprayed uniformly by the
It has now been surprisingly found that a harmonious uniform
optimum treatment of the material can be achieved by this com-
bination. The annular-gap nozzle works "amidships" and "under-
bed". The material falling onto the spray pancake is received
by the process air cushion and is treated in an especially
harmonious and uniform manner.
Even in the case of very large test batches up to 650 kg, a
perfect granulating, coating and drying process is achieved.
The air cushion on the bottom side keeps the bottom surface
completely free of sprayed substance, i.e. all the sprayed
substance is fed into the material, so that no spray losses
occur, which is extremely important in particular in the phar-
In a further embodiment of the invention, discharge openings
for support air are provided between the orifice of the annu-
lar-gap nozzle and the bottom lying underneath in order to
effect a support cushion on the underside of the spray pancake.
It is generally known that a certain vacuum is produced in the
immediate region of a nozzle orifice, and this vacuum results
in accumulations of material next to the spray orifice. In the
case of the spray pancake mentioned at the beginning, no prob-
lem is to be seen on its top side in this respect, since of
course the material particles fall down centrally and are di-
rected away horizontally. On the underside of the spray pan-
cake, however, such vacuum zones could gradually cause particle
accumulations. Support air is provided by the provision of the
additional discharge openings, this region on the underside in
the region of the orifice of the annular-gap nozzle being
"blown free" by said support air. A further additional effect
is that the support air can actually support the sprayed planar
spray pancake on its underside, that is to say said support air
prevents the spray pancake from undesirably moving downward on
account of the gravitational force or on account of the spray
cone forming in cross section. This rules out the possibility
of spray losses or of the sticky materials being deposited on
the top side of the bottom.
In a further embodiment of the invention, the support air is
provided from the annular-gap nozzle itself and/or by process
These measures enable the support air to be brought about in
many different ways. Discharge openings may be provided on the
annular-gap nozzle itself, via which discharge openings some of
the spray air discharges in order to help to form the support
air. In addition or alternatively, some of the process air
which flows through the bottom can be directed in the direction
of the underside of the spray pancake and can thus help to form
the support air.
In a further embodiment of the invention, the annular-gap noz-
zle has an approximately conical head, and the orifice runs
along a circular area of a conic section.
This measure has the advantage that, by means of the cone, the
material particles moving vertically from top to bottom are fed
uniformly, smoothly and specifically onto the spray pancake
which is sprayed from the circular spray gap in the bottom end
of the cone.
In a further embodiment of the invention, a frustoconical wall
is provided in the region between the orifice and the bottom
lying underneath, this frustoconical wall having through-
openings for support air.
This measure has the advantage that the abovementioned harmoni-
ous deflecting movement is maintained by the continuation via
the frustum, and support air can discharge through the through-
openings in this region and provides for the corresponding
support on the underside of the spray pancake.
In a further embodiment of the invention, an annular slot for
process air to pass through is formed between the underside of
the frustoconical wall.
This measure has the advantage that the transfer of the mate-
rial particles to the air cushion of the bottom can be con-
trolled especially effectively and, starting in a specific
manner/ can be carried out directly in the region below the
In a further embodiment of the invention, an orifice of a feed
for a substance is arranged above the annular-gap nozzle.
It has been found that an additional substance can be fed very
effectively on account of the harmonious flow of the selected
combination of annular gaps and annular-gap nozzle. It is
therefore possible, for example, to directly feed a powder
centrally onto the spray pancake when the latter is being
formed, so that a powder can be put in a firmly adhering manner
onto the surface, made sticky by the nozzle, of the material to
be treated. As a result, a rapid increase in the layer thick-
ness during the coating can be achieved. This is not the only
advantage. A further considerable advantage consists in the
fact that, for example, it is possible to feed an active sub-
stance which is sensitive to moisture and therefore cannot be
processed in a suspension or in a solution and sprayed through
the annular-gap nozzle. In this case, the annular-gap nozzle
sprays only the sticky medium; the actual active substance is
fed centrally as powder. This further feeding, which of course
from the fluidic point of view is an additional parameter to be
taken into account, can therefore be carried out, since a
highly defined and harmonious flow can be achieved by the
In a further embodiment of the invention, guide elements are
arranged between the annular guide plates, these guide elements
additionally imposing an extensive flow component on the proc-
ess air passing through.
This measure known per se has the advantage that the corre-
sponding extensive component motion can be imposed by these
guide elements in order to form the toroidally rotating band of
uniformly swirled material particles, which as a result can
uniformly strike the planar spray pancake.
It goes without saying that the abovementioned features and the
features still to be explained below can be used not only in
the specified combination but also in other combinations or on
their own without departing from the scope of the present in-
The invention is described in more detail below with reference
to a few selected exemplary embodiments in connection with the
attached drawings, in which:
Fig. 1 shows a highly schematic diametral cross section through
an apparatus for treating particulate material, and
Fig. 2 shows a corresponding section with an additional feed
for a further substance.
An apparatus shown in fig. 1 for treating particulate material
is provided overall with the reference numeral 10.
The apparatus 10 has a container 12 with an upright cylindrical
wall 14. This wall 14 encloses a corresponding process chamber
The process chamber 16 has a bottom 18, below which an inflow
chamber 20 is located.
As disclosed, for example by DE 192 48 116 B3 mentioned at the
beginning, the bottom 18 is composed of a total of ten annular
guide plates situated one above the other. The ten guide plates
are set one above the other in such a way that an outermost
annular plate connected to the wall 14 forms a lowermost annu-
lar plate, on which the further nine inner annular plates are
then placed, these nine inner annular plates partly overlapping
the respective annular plate underneath.
For the sake of clarity, only some of the guide plates are
provided with reference numerals, for example the two guide
plates 22 and 23 lying one above the other. By this placing one
above the other and by the spacing, an annular slot 25 is
formed in each case between two guide plates, through which
slot 25 process air 28 having an essentially horizontally di-
rected component motion can pass through the bottom 18, as is
of course known per se. Inserted from below in the central
uppermost inner guide plate 24 in its central opening is an
annular-gap nozzle 30. The annular-gap nozzle 30 has an orifice
32, which has a total of three orifice gaps 33/ 34 and 35. All
three orifice gaps 33, 34 and 35 are oriented in such a way
that they spray approximately parallel to the bottom 18, that
is to say approximately horizontally with a looping angle of
360°. Spray air is forced out via the top gap 33 and the lowest
gap 35, and the liquid to be sprayed is forced out through the
middle gap 34.
The annular-gap nozzle 30 has a rod-shaped body 36 which ex-
tends downward and contains the corresponding passages and feed
lines, as is known per se. The annular-gap nozzle may be de-
signed, for example, like the atomizing nozzle from DE 102 32
This annular-gap nozzle may be formed, for example, with a
"rotary annular gap", in which the walls of the passage through
which the liquid is sprayed rotate relative to one another in
order to rule out clogging or lumping, so that spraying from
the gap 34 can be effected uniformly over the entire looping
angle of 360°. With respect to the longitudinal axis of the
body 36 of the annular-gap nozzle 30, there is therefore a
spray angle of 180°.
The annular-gap nozzle 30 has a conical head 38 above the ori-
In the region below the orifice 32, there is a frustoconical
wall 40 which has numerous openings 42. As can be seen from
fig. 1, the underside of the frustoconical wall 40 rests on the
innermost guide plate 24, to be precise in such a way that a
slot 26 through which process air can pass is formed between
the underside of the frustoconical wall 40 and the guide plate
24 lying underneath and partly overlapping with said wall 40.
The flow conditions which form in the run-in state are shown in
the right-hand half of fig. 1.
h planar spray pancake 44 discharges from the orifice 32. Due
to the air which passes through the openings 42 in the frusto-
conical wall 40 and which may be, for example, process air, a
support air flow 46 forms on the underside of the spray pancake
44. Due to the process air 28 which passes through the numerous
slots 25, 26, a radial flow forms in the direction of the wall
14 and is deflected upward by the latter, as shown by an arrow
48. The process air and the material to be treated now separate
from one another, the process air is drawn off through outlets,
the swirled material is moved radially inward and falls verti-
cally downward in the direction of the conical head 38 of the
annular-gap nozzle 30 on account of the gravitational force.
The material falling down is smoothly diverted there and is
directed onto the top side of the spray pancake 44 and is
treated there with the sprayed medium. The sprayed particles in
the spray pancake move away from one another, since of course a
considerably larger space is available to the particles after
leaving the annular orifice 32. In the region of the spray
pancake, the material particles to be treated collide with
liquid particles and, remaining in this direction of movement,
are moved away from, one another and in the process are treated
very uniformly and harmoniously with process air, that is to
say they are dried.
A section comparable with the section in fig. 1 is shown in
perspective in fig. 2, the apparatus shown there being provided
overall with the reference numeral 50. Here, too, there is a
container 52 which has a cylindrical upright wall 54 in which a
process chamber 56 is defined. As described above in connection
with fig. 1, the bottom 58 is composed of ten guide plates
correspondingly placed one above the other, only the two guide
plates 62 and 63, for example, being designated here. The in-
flow chamber 60 is then again located below the bottom 58.
It is shown here that guide elements 64 and 65 are arranged
between the guide plates, these guide elements 64 and 65 lead-
ing to a situation in which not only does the process air pass-
ing though between the guide plates 62 and 63 flow exactly
radially outward, but a certain extensive component motion is
imposed on said process air, as shown by the arrow 68.
Here, too, a corresponding annular-gap nozzle 70 as described
above is again arranged centrally. A feed 72, for example a
laterally fed pipe, is arranged centrally above the annular-gap
nozzle, the orifice 74 of the feed 72 lying exactly coaxially
centrally above the annular-gap nozzle 70. The position of the
orifice can be adjusted vertically.
This makes it possible, for example, to bring a solid in the
form of a powder 78 onto the top side of the planar spray pan-
cake sprayed from the annular-gap nozzle 70.
In both configurations mentioned, the annular-gap nozzle 30 or
70, respectively, is designed in such a way that it can be
removed from the bottom from below even during operation, for
example in order to check for a malfunction or the like. Before
removal, the feed of the spray liquid is of course stopped;
however, it is still possible to circulate the material in the
apparatus 10 or 50, since a process-air column rising upward
forms in the central hole, so that it is impossible for mate-
rial particles to fall through this opening. This is again a
consequence of the highly defined harmonious swirling movement
within the limits of the toroidally rotating band.
1. An apparatus for treating particulate material, having a
process chamber (16, 56) which is intended for receiving and
treating the material and has a bottom (18, 58) which is com-
posed of a plurality of overlapping guide plates (22-24; 62,
63) which are placed one above the other and between which
annular slots (25, 26) are formed, via which process air (28,
68) having an essentially horizontal component motion directed
radially outward can be introduced, an annular-gap nozzle (30,
70) being arranged centrally in the bottom (18, 58), the ori-
fice (32) of this annular-gap nozzle (30, 70) being designed in
such a way that a planar spray pancake (44) which runs approxi-
mately parallel to the bottom plane can be sprayed.
2. The apparatus as claimed in claim 1, characterized in that
discharge openings (42) for support air (46) are provided be-
tween the orifice (32) of the annular-gap nozzle (30, 70) and
the bottom (18, 58) lying underneath in order to effect a sup-
port cushion on the underside of the spray pancake (44).
3. The apparatus as claimed in claim 2, characterized in that
the support air (46) can be provided from the annular-gap noz-
zle (30, 70) itself and/or by process air (28, 68) .
4. The apparatus as claimed in one of claims 1 to 3, charac-
terized in that the annular-gap nozzle (30, 70) has an approxi-
mately conical head (38), and in that the orifice (32) runs
along a circular circumferential line of a conic section.
5. The apparatus as claimed in claim 4, characterized in that
there is a frustoconical wall (40) in the region between the
orifice (32) and the bottom (18, 58) lying underneath, this
frustoconical wall (40) having through-openings (42) for the
support air (46).
6. The apparatus as claimed in claim 5, characterized in that
an annular slot (26) for process air (68) to pass through is
formed between the underside of the frustoconical wall (40) .
7. The apparatus as claimed in one of claims 1 to 6, charac-
terized in that the orifice (74) of a feed (72) for a substance
(78) is arranged above the annular-gap nozzle (70) .
8. The apparatus as claimed in claim 7, characterized in that
the position of the orifice (74) can be adjusted vertically.
9. The apparatus as claimed in one of claims 1 to 8, charac-
terized in that guide elements (64, 65) are arranged between
the annular guide plates (62, 63), these guide elements (64,
65) additionally imposing an extensive flow component on the
process air (68) passing through.
An apparatus (10) for treating participate material has a proc-
ess chamber (16) for receiving and treating the material. A
bottom (18) is composed of a plurality of overlapping guide
plates (22—24) which are placed one above the other and between
which annular slots (25, 26) for process air to pass through
are formed. An annular-gap nozzle (30) is arranged centrally in
the bottom (18), the orifice (32) of this annular-gap nozzle
(30) beihg designed in such a way that a planar spray pancake
(44) which runs approximately parallel to the bottom plane can
be sprayed. (Fig. 1)
|Indian Patent Application Number||2409/KOLNP/2005|
|PG Journal Number||25/2011|
|Date of Filing||28-Nov-2005|
|Name of Patentee||HUTTLIN, HERBERT|
|Applicant Address||RUMMINGER STRASSE 15, 79539 LORRACH, GERMANY|
|PCT International Classification Number||B01J 2/16|
|PCT International Application Number||PCT/EP2004/010096|
|PCT International Filing date||2004-09-10|