Note: Descriptions are shown in the official language in which they were submitted.
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~PPARATUS FOP~ HE~TINt: AND/OR DRYING
This invention relates to apparatus for heating
and/or drying of the klnd disclosed in the preamble
to claim 1.
Such apparatus for the treatment of wet materials
such as fishmeal, comminuted offal, mash *rom
breweries and similar moist, glutinous materials of
animal or vegetable origin are usally designed for
high performances, i.e. for the drying of several
tons of material at a time.
Such an apparatus is known from Danish patent no.
138.406, where the annular channels with hollow
spaces for the heating medium in each drying element
are in the orm of a spiral for the through-flow of
steam. The channels are spiral shaped, because one
c~n hereby more easily drive the condensate out of
the channels, 90 that a good and continuous through-
flow of steam is achieved. However, this form of
channel gives rise to drawbacks from tha point of
view of production, the reason being that in practice
the spiral shape is produced by a composltion of
circular sectors of suitably curvad bands, in that
these pieces of plate material are welded onto the
disc-shaped rotor elements. This glves rise to
difficult welding processes. Moreover, the ends of
the bands must also be welded together, naturally all
pressure-tight and generally executed in stainless
materials.
The ob;ect of the invention is to provide an
apparatus of the kind in question, but of such a con-
figuration that the production is to a great axtantmade easier without hereby giving rise to other
disadvantages.
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In accordance with the invention ther~ is provided apparatus
for heating and/or drying wet comminuted material including
a stationary housing rotatably accommodating a hollow rotor
having an inlet means and a discharge means for a heat medium,
annular drying elements disposed at intervals along the hollow
rotor and at least two hollow annular channels providing the
annular drying elements, to which the heating medium is fed
in parallel. Each of the annular drying elements comprises
two substantially planar plates directly welded to each other
so as to be coupled together and to form one drying element.
At least one of the two substantially pl~nar plates is
deformed so as to form the at least two annular channels
directly in the said at least one substantially planar plate.
By virtue of the above noted features of the present
invention, it is possible to feed several channels in parallel
at one time, which gives a more uniform distribution of heat
in the drying element and the possibility for the supply of
more thermal energy than wi~h the known constructions. In
practice, no probl~ms arise with pos~ible condensate if the
heating i9 effected by steam. ~he heating can, ho~ever, also
be carried out with, for example hot oil or the like. The
supply of l~rge amounts of thermal energy is of great
importance if, for example, the comminuted material shall ~e
boiled and possibly sterilized as quickly as possible.
With the new configuration of the appara~us, positioning of
the annular channels can be variad since the annular channels
can be placed in any positiQn over the whole of the drying
elements, i.e. in a one-sided or two-sided formation and
closely at the side of each other, or with a distance between
them. In accordance with still further features of the
present invention, the annular channels are configuration on
both sides of the drying elements so that a very great supply
of thermal ener~y can be achieved together with a uniform
heating of ~he whole of the drying element.
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The plates may be, in accordance with the present invention,
be roundels, with both roundels in e~ch drying element being
deformed for ~he formation of the channels. With such an
arrangement, the production is simplified since the welding
of the channel parts is avoided and the drying elements are
produced by providing a plate with suitable deformation so
that the desired channel pattern arises.
While the plates are preferably roundels, and it can be
sufficient for one roundel in each pair to be deformed for the
formation of channels, however, according to the invention,
the two annular channels do not necessarily have the same
cross-sectional area, whereby the possibility is provided for
channels of greater cross-sectional area and thus a greater
supply of thermal energy, hereby increasing the capacity of
the apparatus. This channel configuration also offers
advantages from the point of view of production technology.
Since the annular channels in each drying element are not, in
fact, of equal length, they do not have the same resistance
to flow. In order to achieve a uniform temperature
distribl1tion across each drying element, the channels may have
a greater cross-sectional area the greater the distance from
the channels and/or the annular channels mAy be disposed in
a circular manner on the drying element.
In accordance with yet further features of the present
invention, the circular channels are advantageously concentric
with respPct to each other, whereby, the whole of the welding
operation in~olved in welding the channels onto the drying
elemen~s can be automated and carried out by simple welding
robots, and a very even and uniform weld seam requiring the
minimum of after treatment is achieved.
The circular channels may alsol in accordance with the present
invention be concen~ric with the drying element and the rotor
and/or an outer edge of the annular drying elements may be of
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a polygonal configuration, whereby, the possibility is
provided for a large number of channels on each drying
element, and herewith a great supply of thermal energy.
The annular channels may be of a polygonal configuration
corresponding to the outer edge of the annular drying element
and/or the outer edge of the drying element may be a
quadratic, whereby changes can be made in the pattern of the
stirring and the heat distribution, e.g. depen~ing on what
kind of materials are to be handled. In accordance with
additional features of the present invention, a supply channel
for the heating medium may be disposed on one side of the
heating element with a return channel for the heating medium
being disposed on the other side of the drying element. By
virtue of this arrangement, an optimum utilization of raw
materials is realized in that the drying elements can be
produced by the shearing of lengths of material which are then
worked up in the formation of channelsl etc.
With the heating medium supplied on the one side of the drying
element and the return flow on the other side, the channels
can be executed in an almos~- completely annular manner.
Thereby resulting in a very unîform heat distribution, and
avoiding thP supply channel and the return channel lying in
each oth~r~s way during the welding operation. With some
embodiments of the drying element, it can be advantageous that
both the supply channel and the return channel are positioned
on the same side, for example on the same side as the annular
channels.
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4a
Tha invent~on will now be described in more detail
with refarence to tha drawing, in that
fig. 1 shows a schematic longitudinal section in an
apparatus according to the invention,
fig. 2 shows on a larger scale a plan view of a
drying element according to a first em-
bodiment of the invention,
fig. 3 shows a radial section of the drying elemantin fig. 2 saen in the direction III-III,
fig. 4 shows a plan view of a drying element
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accordin~ to a second embodiment of the
invention,
fis. 5 shows partly a radial section of the drying
element in fig. 4 seen in the direc-tion V-V,
fig. 6 shows a plan view of 2 drying element
according to a third embodiment of the
invention, and
fig. 7 shows partly a radial section of the drying
element in fig. 6 seen in the direction VII-
VII.
The apparatus 1 shown schematically in fig. 1 com-
prises a stationary housing 2, possibly provided with
a heat shroud, a filling opening 7 for the material
to be dried, and a discharge opening 8 for the
finish-dried materlal. The material introduced is
dried ~y a haated, rotating rotor 3 with aircular,
plane drying elements 9 disposed at intervals. For
the sake of clarity, the expression drying elements
will be used when referring to the part ~, although
for different applications it heats the material more
or less.
When new, wet material is continously introducsd into
the apparatus, the material to be heat~d or boiled
will migrate towards the discharge opening 8. The
stationary housing 2 has not-shown discharge openings
for the steam which is given off by the wet material
during the drying.
The rotor 3 has a supply pipe 4 for the heating
medium, e.g. steam, leading to a cen-tral pipe 11, and
a dischargs pipe 5 for steam plus a second discharge
pipe 6 for condensate. The mode of operation is, in
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fact, the same as that known, e.g. from Danish patentno. 138.406.
In figs. 2 and 3 is seen a drying elemsnt 9 on a
larger scale and with two circular and concentric
channels 10 which are concentric with the ro-tor 3,
produced by arched, circular strips of stainless
steel being welded to the drying element 9, which is
a circular, plane disc, also of stainless steel.
The channels 10 are fed in parallel via a supply
channel 12, which via a supply pipe 14 is connected
to the central pipe 11. When the heating medium has
passed around through the channels 10, it passes
through holes 16 in the drying element 9 -to a return
channel 13 on the other side of the drying element,
and via a return pipe 15 to the rotor 3.
The channels 10 can have identical through-flow
clearance, or be configured with different clearance
and hereby regulate ths through-flow resistance as
dasired. The through-flow resistance can also be
regulated by inserting means such as throttle
elements or $he like. It is hereby ensured that the
flow of heating medium through the channels 10 is as
desired, e.g. uniform through-flow in all the
channels.
In the example in figs. 2 and 3, the channels 10 are
shown one-sided on the one side o~ the drying element
9. It will be obvious that the channels can also be
disposed on both sides of the drying element 9,
sither opposite one another or staggerad from one
another. The channals can be disposed at intervals
from one another or closely up against one another,
all depending on how uni~oxm the temperature distri-
bution is desired to be and on how great a supply of
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heat is required.
Figs. 4 and 5 show an example of a second embodiment
of the drying element 9 , in that two roundals 17,18
are suitably deformed and joined together, e.g. by
welding. In the shown example, both roundels are de-
formed, but in practice it is sufficient for only one
of the roundels to be deformed while the other is
plane. In the shown example~ the channels 10 are
disposed ~mmediately up against each other ovsr the
whole of the drying element 10 , but naturally thsy
can also be distributed with distance betw~en them as
shown in ig. 2.
In figs. 6 and 7 is shown a spscial embodiment of the
drying element shown in figs. 4 and 5, in that the
roundels 17 and 18 are provided with special channels
10 , so that the drying element 9 is given an even
haat distribution, in that the innermost channels
have less clearance than the outermost, e.g. evenly
decreasins as shown, whereby tha shorter the
channels, the greater becomes the through-flow
resistance.
In figs. 4-7 the supply means and the return means,
2.g. pipelines, for the heating medium and possible
condensate, are merely outlined. It will be obvious
to those familiar with the art that supply pipes and
discharge pipes for the channels 10 and 10 can be
executed in many other ways than those outlined.
All of the shown channels 10,10 ,10 are shown with
circular cross-sectional profile, but it will be
obvious to those familiar with the art that
innumerable other cross-sectional profiles can ba
used and produced with the same effect as the above-
described, and without deviating from the basic
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spirit of the invention.
In the examples in the drawing, all of the drying
elements 9,9 ,9 are shown with a circular
peripheral edge, and all channals 10,10 ,10 are
similarly shown circular. It will be obvious to those
familiar with the art that these parts can also have
other geometric forms. For example, the drying
element can be polygonal, possibly with a quadratic
outer edge, and have circular channels or channels
which follow the geomatry of the edge. Nor is there
anything to prevent a circular drying element from
having channels with another geometry, for example
polygonal.
