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Патент USA US3071340

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Jan, 1, 1963
Filed Nov. 9, 1959
2 Sheets-Sheet 1
Gihééer cl'lz'ai’eb?g
BY 6ll°kuobsy gain‘
Jan. 1, 1963
Filed Nov. 9, 1959
2 Sheets-Sheet 2
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Unite States Patent
Gunther Jaclrering, Harnrn, Westphalia, Germany, as
signor to Altenhurger Maschinen G.m.h.H., Post
Wabern, Bezirk Kassel, Germany, a ?rm of Germany
Filed Nov. 9, 1959, Ser. No. 851,782
Claims priority, appiication Germany Nov. 18, 1958
3 Claims. (Cl. 241-53)
Patented Jan. 1, 1963
rotary discharge apparatus located behind the last grind
ing stages. The result was substantial impediments in
operation, particularly since the centrifugal force must
be quite high for the required high circumferential veloci
An object of the present invention is the provision of a
grinding method and a grinding apparatus which elimi
nate the above described drawbacks of prior art con
This invention relates to a method and an apparatus 10 structions and which make it possible to regulate in a
most effective manner the relationship of the amount of
for ?ne grinding, and refers more particularly to a grind
air to the amount of the substance to be ground.
ing apparatus having a regulated feed of the material to
Other objects will become apparent in the course of the
be ground and a regulating and sorting withdrawing de
vice for the ground substance.
In recent times, industrial grinding procedures have
eliminated to a large extent the standard crushing meth
ods, such as the impact, the throwing of the material, the
following speci?cation.
The present invention is based in part on the discovery
that even the ?rst grinding stage must be charged com
pletely uniformly. ‘Consequently, according to this in
vention, the substance to be ground is introduced with an
air current underneath the rotor, and the material is dis
tributed completely uniformly over the entire cross-section
before it reaches the ?rst grinding stage. The supply of
air is arranged in such manner that immediately after
pneumatically and is connected through zones of cyclones
the mechanical-1y carried out supply of the substance to
or eddies. The material is subjected in these cyclone zones
be ground takes place, an air passage provides the suc
to intensive movements, changes in pressure and charges
of energy, so that an intensive grinding operation takes 25 tion of the amount of air which is necessary for the fur
ther transportation of the substance to be ground. The
place which is also effected by the friction of the particles
of air which is necessary for grinding purposes
against each other. This procedure is particularly ad
and which is considerably greater than the amount of air
vantageous for ?ne grinding or extra ?ne grinding.
required for transportation, is sucked in only in the ven
structurally this procedure is carried out through the
tilator zone.
compression of the material, the friction, the shearing and
the press rolling, and instead have placed in the fore
ground machinery wherein the substance to be ground,
usually consisting of individual pieces, is transported
use of a rotor having radial blades which move past a
vertically corrugated stator, whereby the eddies created
behind the blades are particularly effective, since in these
This process in accordance with the present invention
makes it possible to regulate the ratio of the amount of
air to the amount of the ground substance in the best
possible manner and with very ?ne precision. The de
zones the substance to be ground is subjected alternately
to high pressure and low pressure which are produced
by the quick movement of these blades past the corru 35 scribed second supply of air, shortly before the distributing
ventilator state, attains by renewed cyclonic mixing, for
gated stator. These grinding procedures are particularly
?rst time, a completely uniform mixture of air and
noticeable in the case of substances, the structure of which
of the substance to be ground.
has inner tensions and which have the tendency to break
The invention will appear more clearly from the fol
up along these inner tension lines.
lowing detailed description when taken in connection with
I have found in the course of my studies of the opera
the accompanying drawings showing by way of example,
tion of such machines that it is necessary to pay more at
a preferred embodiment of the apparatus of the present
tention to the supply of air and to the regulation of the ~
amounts of air than hitherto was considered necessary
In the drawings:
on the ground of the prior art knowledge of the interre
FIG. 1 is a section through a grinding device of the
lated procedures. Since air participates in the grinding
present invention and illustrates the supplying device and.
process and is also partly a carrier of the grinding energy,
the so-called air lock.
there must be a predetermined optimal ratio between the
FIG. 2 is a transverse section along the line II-II of
amount of air, the amount of the substance to be ground,
FIG. 1.
and the velocity of air in the grinding current.
FIG. 3 is a transverse section along the line III—III
In some prior art devices, the substance to be ground is 50
of FIG. 1.
transported directly to the level of the ?rst and second ro
FIG. 4 is a transverse section along the line 1V-—IV
tor blades. It was then found that breaking and increased
of FIG. 1.
Wearing out effects were produced, and that there is a
substantial drop in the grinding output both qualitively
FIG. 5 is a top view of the upper discharge device for
and quantitively. According to another machine known in 55 the ground substance.
prior art, the substance to be ground is carried centrally
FIG. 6 is a plan view of the rotary discharging body.
through a high central shaft to the lower rotor blades, but
FIG. 7 is a partial central section through the body
then it must reverse its direction of flow to the extent
shown in FIG. 6 with parts shown in side elevation.
of 180°, with the result that a uniform ?ow which is so im
FIG. 8 is a section through one of the shock plates of
the rotor.
portant for the grinding, cannot be attained. Further
more, the parts wherein the ?ow of the substance is
FIG. 9 is a side view of the shock plate shown in
PEG. 8.
changed are subjected to increased wear and tear.
Prior art rotors of grinding apparatus were provided
The grinding apparatus shown in the drawings in
with rigid shock plates with a constant spacing between
cludes a main substantially cylindrical casing 12. carrying
the edge of the stator and the outer edge of the plates.
a vertical shaft 4, which is driven by any slidable means;
This constant spacing did not take into consideration the
not shown in the drawings, and which carries the rotors
different grinding procedures of the individual grinding
stages and produced a drop in output. Another draw
back was caused by the grinding method which employed
consisting of superposed plates 11 forming the different
grinding stages. The shaft 4 also carries a rotary body
14 for the discharge of the ground substance.
pressure variations which followed each other in quick suc 70
The device supplying the substance to be ground in
cession. The high oscillation frequencies which were thus
a supply hopper 1 leading to a tubular casing con
produced, caused regularly the breakage of stems of the
taining a feed screw 2.. A vertical pipe 3 connects the
upper discharge chamber of the machine with the feed
screw. A short pipe connects the casing of the feed screw
with the main casing 12 of the machine and is provided
with an opening 5 which will be described hereinafter
as an air vent or an air lock.
The casing 12 of the machine which constitutes the
receives the second current of air which carries the sub
stance through the grinding stages provided by the rotors
11. The amount of this second current of air which is
introduced into the machine through the openings 7 and
8, is regulated by adjusting the size of the openings 7
and 8 by means of the shutters 9 and 10 which move in
the direction of arrows shown in FIG. 2. This regu
stator, may be provided with vertical corrugations if
lation provides the correct mixture of air and the sub
stance to be ground required for the speci?c grinding
The lower portion of the casing 12 contains a supply
ing chamber 6 which is located directly above the bottom
Furthermore, the operator before the grinding oper'
of the casing ‘12. The bottom is provided with openings
ation can conveniently adjust the position of the shock
7 and 8 for the in?ow of the second current of air serv~
plates 11 relatively to the casing ‘12 depending on the
ing as the carrier of the substance during the grinding
type of the substance to be ground and the required ex
operation. As shown in FIG. 2, the openings 7 and 8
tent of grinding. As already stated, this is possible through
may be conveniently closed or only partly opened by 15 the provision of longitudinal slits in the shock plates 11
shutters 9 and 10, so as to provide the correct amount
of the rotors.
of air. Air is supplied to the openings 7 and 8 through
The plates 11 provides air cyclones which quickly fol
passages surrounding the shutters.
low each other and which result in the grinding of the
The rotor discs of the machine carry shock plates 11.
substance which passes upwardly through the rotors.
According to the present invention, the plates 11 are not 20 When the substance has left all the individual grinding
located any more, as was the case in prior art, at the
zones of the rotor, it reaches the upper ejecting chamber
same distance from the casing or stator 12 for each rotor
13 containing the rotary body 14. As already stated,
stage, but can be shifted closer to or further away from
the ejecting plates 17 of the body 14 are located at such
the casing 12 depending on the type of the substance to
an angle to the inner surfaces of the casing 12, that
be ground and the required extent of grinding. In order 25 they will convey the heavy or large particles, or such
to attain this, the shock plates 11 are provided with longi
particles which have not been su?iciently ground, tan
tudinal slits which make it possible to adjust the plates
gentially toward the outlet 18. Due to the provision of
radially. Obviously, the adjustment must be carried out
the trap 19, only the speci?cally heavy particles which
within such limits that the plates 11 will not contact the 30 were driven against the inner walls of the casing 12, will
casing 12. FIG. 3 shows diagrammatically and in top
be able to pass through the out?ow passage 18. Ob
view the arrangement of the shock plates 11.
viously, it is possible to change the position of the trap
The upper portion of the casing 12 contains a discharge
‘19 so as to adjust the amount or the size of the particles
chamber 13. A rotary body 14 which is driven by the
which will reach the passage 18.
shaft 4 is located in the chamber 13. The rotary body 14 35 if the ejected particles which pass through the passage
carries plates 14a provided with milled grooves 15 shown
18 are not to be treated any more. they can be easily
in FIG. 7. Inserts or pieces 16 ?t in these grooves and car
ry ejecting plates 17 which extend at such an angle to
collected by an suitable means (not shown), or placed in
the casing 12 that the heavy, large or unground particles
However, as shown in FIG. 1, the out?ow passage can
of the substance being treated can be ejected tangentially. 40 be connected with a vertical tube 3 so that the particles
The chamber 13 communicates with an outlet 18 shown
in FIG. 4. A trap 19 is located at the outlet 18 and forms
will be resubmitted to the feed screw 2 and reintroduced
into the machine for rpnewed grinding.
a narrow passage 21 which permits only the speci?cally
FIGURE 4 illustrates by arrows the process of remov
heavy particles to pass through the outlet 18 (FIG. 4).
The top of the casing 12 is connected with ventilator
ing the particles, while the chamber 13 is illustrated in
FIG. 4. F168. 6 and 7 show the construction of the
rotary body 14 provided with the supports 16 and the
22 (FIG. 1) which creates a suction, by means of which
the particles which have been ground to the desired ex
tent of ?neness, are sucked into the out?ow casing 23.
As shown in FIG. 5, the casing 23 has the form of a
ejecting plates 17.
The operation of the described apparatus is as follows:
Particles of the substance to be ground are introduced
into the machine through the hopper 1 and reach the feed
The substance which has been ground to the desired
extent, is sucked in from the chamber 13 through the
upper ventilator 22 and reaches the out?ow casing 23
which is of spiral form, as shown in FIG. 5. The spiral
widens toward the exit so that here the ground particles
have only small velocities.
screw 2. The feed screw 2 which is driven by any suit
able means not shown in the drawings, transports the
can be used to receive the particles leaving the casing 23.
Any suitable separator, not shown in the drawings,
substance to be ground toward the opening 5. Should the
Extensive experimentations with apparatus constructed
feed screw 2 transport a larger amount of substance
in accordance with the above described principles of
than can be ground by the machine, the supply of this
substance provided by the feed screw 2 will be gradually
the present invention, have produced the surprising ef
accumulated at the opening 5 and in time will cover a
part of the opening 5. If the supply continues to in
crease thereafter, the substance will close the opening 5
entirely, so that no more air will be able to ?ow into
the interior of the machine through the opening 5. Then
feet that the described method of introducing the sub
stance to be ground and of moving it by air currents
in the described manner, results in an output which
is many times greater than that of prior art machines.
While heretofore there was always the danger that the
machine would be operated with an insufficient amount
due to insufficient ventilation effect and also since the
of air and that the machine may be overheated to an
air current serving as a carrier for the substance to be
extent which will endanger its further operation, the
novel feed methods of the present invention have not
only eliminated this danger, but have also made possible
ground is interrupted, the grinding process will be in
terrupted completely. Thus, the opening 5 serves not
grinding operations which heretofore could be carried
only as an air vent, but also has a self-regulating air lock
and as a safety device, in that instead of a ?ow of air, 70 out by prior art machinery either with considerably greater
expenditure or not at all.
the substance to be ground may drop downwardly through
Furthermore, in accordance with the present invention,
the described process makes it possible to combine to
some extent the grinding step with the step of drying
.The substance to be ground carried by air supplied
ground substance. It will be noted in this connection
through the opening 5 reaches the chamber 6 and there 75
the openings 7 and 8, thereby avoiding damage to the
that the temperature in the described machine can be
technically regulated by a regulation of the air supplied
through the openings 5, 7 and 8. Thus, these openings
can be connected with suitable heaters (not shown) so
and above said bottom in said casing, means feeding
a substance to be ground along with air into said casing
and to the lowermost rotor, said bottom having at least
two openings for introducing air into said casing, said
that even warm air with gradually increasing tempera
openings being spaced in the direction of said feed, the
tures can be introduced into the machine. Practical ex
air introduced through said openings forming a separate
perimentation with machines constructed in accordance
current of air transporting said substance upwardly
with the principles of the present invention, has shown
through said rotors, said rotors producing a quickly fol
that in this manner it is possible to introduce air during
lowing sequence of air cyclones for grinding said sub
continuous operation at a temperature of up to 200° C., 10 stance, and shutters carried by said bottom for varying
with the result that the ?nal temperature of the ground
the size of said openings.
substance will drop to the extent of 10%. This makes
it even possible to introduce viscous substances for grind
3. An apparatus for ?ne grinding, said apparatus com
prising a vertical casing having a top and bottom, a
ing purposes into the grinding apparatus.
plurality of blade-carrying rotors located one above the
Obviously, heated air can be introduced into the ap— 15 other in said casing, another casing connected with the
paratus at such locations at which cold or cooled air can
?rst-mentioned casing below said rotors, a feed screw
be also introduced into the apparatus.
located in the second-mentioned casing for feeding a sub
It will be noted that described methods and apparatus
stance to be ground to the ?rst-mentioned casing below
follow the general development of the art which requires
said rotors, said feed screw having an inner end spaced
breaking up procedures, grain ?neness and sorting which 20 from the interior of the ?rst-mentioned casing, the sec
must be always more precise and have greater ?neness.
oud-metioned casing having an air vent opening located
An important advantage of the present invention is that
between said inner end of the feed screw and the interior
it makes it possible to carry out grinding processes in a
of the ?rst-mentioned casing, said bottom having at least
single grinding apparatus which heretofore were not
two openings forming a separate current of air transport
considered possible for continuous operation. A further 25 ing said substance upwardly through said rotors, shutters
advantage is that the described grinding method was
carried by said bottom for varying the size of the last
found to be considerably less expensive and much more
mentioned openings, said rotors producing a quickly fol
etfective in actual operation than methods known in prior
lowing sequence of air cyclones for grinding said sub
stance, said casing having a space between said top and
It is apparent that the example shown above has been 30 the uppermost rotor for unground particles of said sub
described solely for the purposes of illustration and not
stance, a separate rotary body located in said space and
for the purposes of limitation and that it is capable
operatively connected with said rotors, supporting pieces
of many variations and modi?cations within the scope
carried by said rotary body, ejecting plates carried by
of the present invention. All such variations and modi
said supporting pieces and extending at an angle to the
?cations are to be included within the scope of the present 35 radial direction for projecting said unground particles
What is claimed is:
1. An apparatus for ?ne grinding, said apparatus com
against the walls of said casing, a hopper carried by the
second-mentioned casing adjacent the outer end of said
feed screw and a vertical pipe having an upper end con
prising a casing, a vertical row of blade-carrying rotors
nected with the ?rst-mentioned casing adjacent said eject
in said casing, another casing connected with the ?rst 40 ing plates and a lower end connected with the second
mentioned casing below said row of rotors, and a me
mentioned casing between said hopper and the ?rst-men
chanical feed device located in the second-mentioned
tioned air vent opening.
casing for feeding a substance to be ground to the ?rst
mentioned casing below said rotors, said mechanical feed
References Cited in the ?le of this patent
device having an inner end spaced .from the interior of 45
the ?rst-mentioned casing, the second-mentioned casing
Harrington ___________ __ Feb. 18, 1930
having an air vent opening located between said inner
Crites _______________ __ Mar. 30, 1937
end of the mechanical feed device and the interior of the
?rst-mentioned casing, whereby the operative size of
said opening is regulated by an accumulation of said sub 50
stance in the space between said inner end of the me
chanical feed device and the interior of the ?rst-mentioned
casing, the ?rst-mentioned casing having at least one other
air vent opening for feeding the substance to be ground
from the space below said rotors to said rotors.
2. An apparatus for ?ne grinding, said apparatus com
prising a vertical casing having a ‘bottom, a plurality
of blade-carrying rotors located one above the other
Ga?ney ______________ __ Sept. 7,
Crites ________________ __ May 14,
Lykken ______________ __ Sept. 8,
Les Veaux ___________ __ May 15,
Lecher ______________ __ May 31,
Beushausen et al. ______ __ July 5,
Lecher ______________ .. June 26,
France ______________ __ Nov. 15, 1951
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