The invention relates to a device for cooling and/or drying bulk
goods, provided with a bunker having a supply opening for the material to be cooled,
said supply opening being located near the upper side of the bunker, and with a
single grate construction located near the bottom side of the bunker, said grate
construction being provided with a number of bar-shaped means extending at least
substantially parallel to each other, as well as with means for supplying cooling
and/or drying air to the interior of the bunker through the grate construction
at the bottom side of the device and for discharging said air near the upper side
of the device after it has flowed through the material, whilst the bar-shaped means
can be pivoted forwards and backwards about a centre position during operation.
The dimensions of the products which are processed in such a device,
such as mealy products, granular products, flaky products, cylindrical products
etc., can vary within ample margins. Usually the varying dimensions of the products
also require varying dimensions of the passages present between the parts of the
grate construction for passing the material. With the known grate construction
the dimension of said passages can usually not be adjusted, however, so that a
certain grate construction can usually be used for a certain material only and
when another and/or finer and/or coarser material is to be processed it is necessary
to use another device or to build in another grate in a certain device.
The purpose of the invention is to obtain a device of the above kind
which is suitable for processing a large number of different bulk goods.
According to the invention this can be achieved in that the bar-shaped
means are provided with plate-shaped parts extending along both sides of the longitudinal
axes, said plate-shaped parts being arranged such that they can overlap each other
during normal operation, whilst the centre position of the bar-shaped means is
adjustable and the bar-shaped means with the plate-shaped means fixed thereto can
be pivoted forwards and backwards in any set centre position.
The passages for passing the material bounded by the overlapping
plate-shaped parts can be adjusted in a simple manner by changing the centre position
of the bar-shaped means, whilst in every centre position an even discharge of the
products to be processed can be ensured because of the possibility to pivot the
bar-shaped means with the plate-shaped parts fixed thereto forwards and backwards.
It is noted that from the British patent specification 9801/1912
there is known a drying device provided with a large number of floors arranged
at relatively short distances above one another, said floors being built up of
partly overlapping tiltable plates. Drying air is supplied between said floors
and can flow out via passages provided between the plates. At set intervals the
plates forming a floor will be tilted in order to deposit the material present
thereon onto a floor located thereunder. Thus the material will be moved in steps
from the one floor to the next floor. From said publication there is not known,
however, a device provided with a bunker for taking up the bulk goods and with
a single grate construction located near the bottom side of the bunker, built up
of bar-shaped means, which bar-shaped means can be pivoted forwards and backwards
during operation in order to be able to ensure a regular outflow of the material
from the bunker. Nor can an indication be found in said publication with regard
to a possible adjustment of the device for processing various kinds of materials.
From the German patent specification 318,693 there is known a similar
drying device, provided with a number of floors located at short distances above
one another, said floors being built up of a large number of plate-shaped parts
which may overlap one another. The plates are jointly pivotable thereby from the
position in which they form a floor into a position in which the material lying
on a floor falls in one movement onto a floor located thereunder. Neither is any
indication provided in this publication, therefore, with regard to the construction
of a drying device provided with a bunker containing the material to be processed
and a single grate construction located at the bottom side thereof, as constructed
in accordance with the proposal according to the present invention.
In some cases problems may arise when fine products, such as mealy
products, are processed when non-perforated plate-shaped parts are used because,
also when the plate-shaped parts are set such that only narrow gaps are present
between adjacent plate-shaped parts, so much air is still sucked in through the
gaps that local passages are formed in the layer of meal or the like material supported
by the plate-shaped parts.
As a result there may be a very irregular distribution of the air
speed and an irregular degree of flow of air through the meal or the like material
on the surface of the grate construction in such a case.
According to a further aspect of the invention such a disadvantage
can be met in that the plate-shaped parts are perforated.
When using such perforated plate-shaped parts it will be possible,
when meal or the like fine material is processed, to put the plate-shaped parts
into such a position that the edges of the plate-shaped parts are at least substantially
in contact with one another, and it is practically only possible for the air to
flow through the perforation openings during operation, as a result of which an
even passage of air through the material to be processed can be ensured.
The invention will be further explained hereinafter with reference
to an embodiment of the construction according to the invention diagrammatically
illustrated in the accompanying figures.
- Fig. 1 is a diagrammatic view of a device according to the invention.
- Fig. 2 illustrates a few bar-shaped means according to a first embodiment of
the invention in three different positions.
- Figs 3 - 5 illustrate a few further embodiments of the bar-shaped means, each
illustrated in three different positions.
- Fig 6 diagrammatically illustrates a part of a mechanism for regulating the
pivoting of the bar-shaped means about their longitudinal axes.
The device illustrated in fig 1 comprises a frame 1 on which there
is placed a bunker 2. Under the bunker there is located a chute 3 supported by
the frame. Between the bunker 2 and the chute 3 there is arranged a grate construction,
which is built up of a number of bars 4 extending parallel to each other, which
bars are rotatably journalled near their ends in bearings, not shown, fixed to
the frame, such that the bars 4 are pivotable about their longitudinal axes. To
the ends of the bars 4 there are furthermore fitted arms 5 which are mutually
coupled by a coupling rod 6 only diagrammatically indicated by means of a chain-dotted
line. One of the arms 5&min; is longer than the other arms 5 and is coupled, with
its end remote from the relevant bar-shaped means 4, to the piston rod of a setting
cylinder 7, which setting cylinder is coupled to the frame with its other end.
During operation the bar-shaped means 4 can be pivoted forwards and backwards about
their longitudinal axes by means of the setting cylinder 7.
As is also further illustrated in fig 2 three plate-shaped parts
9 - 11, extending along the entire length of the bar-shaped means, are fixed to
each bar-shaped means 4. As appears from the figures thereby the two plate-shaped
parts 9 and 10 extend parallel to and spaced from each other because they are located
on both sides of the bar-shaped means 4 in question and extend in opposite directions
from said bar-shaped means 4 thereby. The third plate-shaped means 11 may be perpendicular
to the two plate-shaped parts 9 and 10 and extends downwards in the position of
the plate-shaped parts illustrated in fig 1.
At its upper side the bunker 2 is provided with a cellular valve
12, via which bulk goods to be processed can be supplied to the interior of the
Cold or hot air for cooling and/or drying can be supplied to the
interior of the bunker 2 via the grate formed by the bar-shaped means 4 with the
plates 9 - 11 fixed thereto, as indicated by means of the arrows A and, after having
flowed through the material present in the bunker 2, be discharged via a pipe 13
connected to the upper side of the bunker 2. Material flowed from the bunker 2
into the chute 3 through the grate-shaped means can be discharged via a spout 14
provided at the bottom side of the chute 3.
As is illustrated in fig 2a the bar-shaped means 4 forming a grate
can be pivoted such that the free ends of the overlapping parts 9 and 10 of adjacent
bar-shaped means substantially touch each other or are located at short distances
from each other, such that the gaps still present between the plate-shaped parts
9 and 10 of the grate-shaped construction are too small to pass the material, so
that no flow of the material from the bunkers is possible.
From the position of the bar-shaped means illustrated in fig 2a,
in which the outlet from the bunker will be at least substantially closed, the
bar-shaped means can be pivoted to an intermediate position illustrated in fig
2b, in which the distance between the overlapping plate-shaped means is such that
material present in the bunker 2 can flow out via the gap present between the plate-shaped
In order to start and stop said outflow the bar-shaped means 4 can
thereby be pivoted at an angle about the set intermediate position or centre position
by means of the setting cylinder 7, as a result of which the material lying on
the plate-shaped means 9 will be put into a slight upward and downward movement.
In particular when products which tend to stick are processed such a displacement
of the material in order to loosen the material is important. The bunker above
the grate construction may be slightly conical towards the top, which will prevent
bridge formation in the material in the bunker.
Because in the centre position illustrated in fig 2b the free end
of the plate-shaped part 10 across which the material flows out of the bunker is
located at a short distance from the plate-shaped part 11 extending perpendicularly
to said plate-shaped part 10, which plate-shaped part 11 extends some distance under
the edge of the plate-shaped part 10, it is prevented that the material flows out
of the bunker too quickly, because the material is braked, as it were, by the plated-shaped
At the same time the plate-shaped part 11 contributes to the rigidity
of the bar-shaped means 4 in order to prevent bending of said bar-shaped means
4 under the influence of the weight of the material present in the bunker.
When it is desired to empty the bunker quickly the bar-shaped means
can be pivoted from the position of the grate illustrated in fig 2a or b at an
angle of about 90°, so that the plate-shaped parts 9 and 10 extend at least substantially
vertically thereby, whilst there is a relatively large gap present between the
free boundary edge of a plate- shaped part 11 located substantially horizontally
in that case and an adjacent bar-shaped means 4. Thus large passages are formed
between the adjacent bar-shaped means 4, through which the material can flow out
freely and without impediment. A little material at the very most will remain
behind on the plate-shaped parts 11 located substantially horizontally in that
case, but this material will also be discharged when the bar-shaped means are pivoted
back towards the closed position of fig 2a.
As is illustrated in more detail in figs 3 -5 the shape of the plate-shaped
means may possibly be adapted to the nature of the products which will mainly be
processed in the device. Thus, in the embodiment according to fig 3, the ends 15
of the plate-shaped parts 10 are bent upwards a little in the direction of the
plate-shaped parts 9 located thereabove. As a result of this the gap between the
overlapping plate-shaped parts can be reduced in a simple manner in the closed position
of the grate.
In the embodiment according to fig 4 not only the edges 15 of the
plate-shaped parts 10, but also the edges 16 of the plate-shaped parts 9 are bent
upwards. The upwardly bent edges of the plate-shaped parts 9 will thereby have
an extra scraping effect on the material in the bunker 2 when the bar-shaped means
are pivoted forwards and backwards during operation.
In the embodiment according to fig 5, on the contrary, the edges
17 of the plate-shaped parts 9 are bent downwards, in order to prevent that e.g.
small spherical products flow through the grate in the so-called closed position
of the grate.
There should always remain an opening between plate parts 9 and 10
for the passage of the air.
Fig 6 illustrates a part of a mechanism for regulating the stroke
of the setting cylinder 7 or the angle at which the bar-shaped means are pivoted
For that purpose an arm 18 is fixed to one of the bar-shaped means
4, which arm co-operates with a pair of switches 19 and 20 arranged on both sides
of the arm. The switch 19 is thereby movable in horizontal direction and adjustable
between the position 19 and the position 19&min; illustrated by dotted lines. In
a similar manner the switch 20 is adjustable in horizontal direction between the
position 20 and the position 20&min; illustrated by dotted lines.
When the arm 18 touches one of the switches the direction of rotation
of the bar-shaped means will be reversed via a mechanism (not shown). It will be
apparent that the angle at which the bar-shaped means are pivoted and the place
of said angle can be influenced by adjusting the switches 19 and 20. A further
switch 21, having a fixed arrangement and co-operating with the arm, is used for
stopping the pivoting motion when the bar-shaped means 4 have been put in the completely
open position, as is e.g. illustrated in fig 2c.
For processing very fine products, e.g. meal, it is desirable to
perforate at least those parts of the plate-shaped parts that project from the
When the plate-shaped parts 9 and 10 are then pivoted into such a
position that the free edges of adjacent plate-shaped parts at least substantially
rest on each other, the air supplied will mainly be supplied to the layer of material
lying above the plate-shaped means 9 and 10 exclusively via the perforations, so
that a very even distribution of air over the grate surface is obtained.
For the discharge of material the plate-shaped parts can be pivoted
at desired moments to a position in which the material can flow out through the
gaps formed between the plate-shaped parts.
The bars 4 may be hollow and perforated, so that a supply of air
over practically the entire grate surface can be created.