Note: Descriptions are shown in the official language in which they were submitted.
ARC-SHAPED AND POLYGONAL CRUSHING TOOTH
ARRANGEMENT IN ROTOR CRUSHERS AND ROLLER
CRUSHERS
FIELD OF THE INVENTION
100011 The subject of the present invention is the arc-shaped and polygonal
arrangement of
crushing teeth on the periphery of rotors or rollers of rotor crushers or
roller crushers (arc
formation and polygonal formation). The tooth height h related to the rotor or
roller outside
diameter D determines whether it is a rotor crusher (wave-type crusher, sizer)
with toothed
rotors (h/D > 0.17) or a roller crusher with toothed rollers (h/D < 0.17).
BACKGROUND OF THE INVENTION
100021 Rotors and rollers equipped with teeth are used in rotor crushers and
roller crushers
to improve the draw-in conditions and to facilitate the crushing by means of a
concentrated
application of force. Of decisive importance here is the arrangement of the
crushing teeth
(tooth formation/crushing tooth arrangement). This arrangement has an effect
on the draw-
in behavior, particularly on the draw-in duration of large chunks of material,
as well as on
the throughput behavior, particularly the material distribution along the
rotor or roller
length (throughput behavior) and finally also on the discharge behavior,
particularly the
oversized and deformed parts in the crushed product. Furthermore, the crushing
behavior,
particularly the needed crushing work as well as the time course of the
crushing force and
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thus also the tooth wear along the rotor or roller length can be influenced by
the formation
of the crushing teeth.
[0003] Eponymous for the tooth formation type is the shape of the connecting
line of the
tooth tips of a row of teeth in the rotor or roller unwinding. For the clear
characterization of
the formation type, at first, it must be determined which partial quantity of
teeth belongs to
a row of teeth, because, otherwise, any number of periodic patterns can be
found. Figure 1
shows this in an example of an unwound roller with spiral tooth arrangement
according to
EP 0 167 178 Bl, in which besides the correct connecting line of the spiral
formation (a),
e.g., also those of an arrow formation (b), multispiral (c) formation or
alignment formation
(d) can be drawn in.
[0004] At first, it follows that the formation type depends only on the shape
or slope of the
axial connecting lines, and radial connecting lines as in Figure 1 (d) are not
eponymous.
The connecting line may be oriented in the radial direction partly (Figure 1
a, b) or even
completely (Figure 1 c), but it must extend over the entire roller length.
Furthermore, if it is
assumed that the shortest and geometrically simplest axial connecting line is
to be selected,
variants (b) and (c) also do not apply and only the desired variant (b)
remains. Thus,
straight lines or polygon courses always form the shortest, but not in each
case the
geometrically simplest connecting line (e.g., arrow formation with curved
arrow flanks
according to EP 1 385 630 B1). Finally, complete equipping of the roller with
teeth results
from radial offset of the row of teeth defined in Figure 1 (a) by the value of
the
circumference pitch tu.
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[0005] Thus, a row of teeth comprises all teeth in the axial direction which
describe the
complete equipping with teeth in the unwinding alone due to radial offset and
form the
shortest and geometrically simplest connecting line (= formation line).
Analogously to the
row of teeth, the toothed ring is defined in the radial direction, such that
the number of teeth
n is the product of the number of toothed rings nu and the number of rows of
teeth nu.
[0006] The tooth arrangements belonging to the free or patented state of the
art can be
defined based on this definition. The simplest formations include the
alignment formation,
in which the row of teeth forms a straight line parallel to the axis of
rotation of the roller or
rotor body. Likewise sufficiently known are various offset formations, in
which the row of
teeth forms a straight line, which is not axially parallel, or a curved
function.
[0007] Thus, EP 0 167 178 B1 discloses a spiral formation, in which the row of
teeth forms
a straight line sloped by an angle in the rotor or roller unwinding. This
formation is found
on the two crushing rollers of a mineral crusher, which rotate in opposite
directions,
between which feed material is crushed. The spiral arrangement of the one
roller may run in
the same direction or the opposite direction to the counter-roller. If the
feed material is fed
parallel to the roller axes from the side (axially parallel feed), then the
opposing spiral
formation leads to a directed transport from the equipped side to the opposite
side of the
roller. On the other hand, same-direction spiral formation brings about an
undirected
transport of material above the rollers. In case of axially vertical feed,
where the material is
above all concentrated in the roller center, the opposing spiral formation is
also only still
conditionally suitable, since it directs the material away from the center
only in one
direction and thus effectively utilizes only one roller half. In both variants
of this formation,
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each tooth of the one roller is axially offset to its corresponding tooth on
the counter-roller
by ta/2 (cf. Figure 1), so that they can mesh with one another during the
rotation of the
rollers.
[0008] If throughput and wear behavior are essential, then a uniform material
distribution
should be noted above all along the complete rotor or roller length. In case
of axially
parallel material feed out from one rotor or roller, this can best be achieved
by an opposing
spiral formation, since this activates an axial transport to the opposite side
and thus relieves
the feed side. Axial transport actions above the rotors or rollers are brought
about by offset-
arranged tooth formation of rotor or roller and counter-rotor or counter-
roller. While they
move on one another, these form an opening angle 6 in the unwinding. In case
of opposing
spiral formation, this corresponds, e.g., to the doubled offset angle y (6 =
27, cf. Figure 1).
Rotor crushers or roller crushers are, however, usually equipped in an axially
vertical
manner, whereby depending on the dumping cross section on the feed conveyor, a
different
material distribution along the rotors or rollers results. An axially parallel
material feed
directed on one side is then less advantageous.
100091 An arrow formation, which is also to be included in the offset
formations, with
which the problem of the one-sided material transport in centric, axially
vertical feed shall
be solved, is described in EP 1 385 630 Bl. The rollers of the multiroller
crusher described
in this publication are equipped with rows of teeth, which run towards the
center in an
arrow-shaped pattern in the roller unwinding. The opposing arrow formations of
both
rollers are usually offset to one another by the half axial pitch ta/2 to make
possible a
meshing of the teeth. The following formations are disclosed in the patent:
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a. Formations with equal/unequal-sided arrow flanks,
b. formations with equally/unequally sloped arrow flanks,
c. formations with straight/hollow-cone-shaped, curved arrow flanks,
d. formations, whose arrow tip points towards the crushing gap / away from it.
[0010] A material transport on both sides to the roller edges is only possible
in case of
arrow tips pointing towards the crushing gap. Otherwise, the material moves to
the rotor or
roller center.
[0011] Furthermore, tooth arrangements, in which the basic formations per rows
of teeth
occur repeatedly, as a result of which a zigzag-shaped (multiarrow formation)
or obliquely
offset (multispiral formation) shape results, are known from the state of the
art.
[0012] It is likewise known to combine a plurality of basic formation types
with one
another in each row of teeth. Thus, DE 20 2006 014 902 U1 describes a spiral-
arrow
formation, for example, of a single-roller crusher, in which the toothed
roller interacts with
an anvil and thus crushes the feed material. The arrangement principle is
subsequently
applied to a two-roller crusher. It is characterized in that the teeth are
first combined into
toothed rings in the circumferential direction. Two adjacent toothed rings of
a roller are
offset to one another by a defined angle and form a pair of toothed rings.
Since, besides the
toothed rings of a pair of toothed rings, the pair of toothed rings of a
roller are also offset
axially, a spiral tooth arrangement with superimposed arrow formation forms.
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SUMMARY OF THE INVENTION
[0013] A basic object of the present invention is to overcome the drawbacks of
the state of
the art and to optimize the draw-in, discharge, throughput, crushing and/or
wear behavior of
rotor crushers and roller crushers by means of improved tooth arrangements.
[0014] The object is accomplished by a crushing tooth arrangement on the
periphery of
both rollers or rotors of a roller crusher or rotor crusher, characterized in
that the rows of
teeth of the rollers or rotors have opposing offset angle courses in the axial
direction, which
correspond to the course of an axial mass flow needed for homogenizing an
inhomogeneous material distribution along the length of the rollers or rotors
(arc
formation).
[0015] The axial mass flow needed for homogenizing or blending arises from the
differential mass balance between the too much or too little fed material in
relation to a
uniform dumping cross section along the roller or rotor axis (Figure 2 A).
Thus, a doubled
parabolic course over the roller or rotor length arises for a real dumping
cross section, with
a linear increase on both sides to a feed maximum in the roller or rotor
center at L/2 (L ¨
roller length), and with maxima at L/4 and 3L/4 and minimum at L/2 for the
material to be
carried away or to be fed axially (Figure 2 B). This axial mass flow, with
which a unifon-n
material distribution along the rotor or roller length is achieved, results
from the integration
of the linear course of the dumping height difference between the idealized
homogeneous
and the real dumping cross section (Figure 2 A, B).
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[0016] Axial feed forces, which are generated in rotating rollers or rotors by
means of tooth
tips of tooth arrangements with an offset angle y> 0, are necessary for
generating this axial
mass flow. The amount of this feed force depends on sin(y) and since sin(y) =
7 applies to
small angles, a proportional connection arises between offset angle 7 and
axial feed force or
speed. As a result of this, the offset angle course needed for homogenizing
corresponds to
the course of the axial mass flow needed for homogenizing (Figure 2 B). A
directed
movement results from the axial feed forces generated in each case only with
an opposing
arrangement of the rows of teeth of both rollers or rotors.
[0017] Since the slopes of a row of teeth of both rollers or rotors correspond
precisely to
the offset angle, its course can be determined directly by means of
integration of the offset
angle course or of the course from axial mass flow (Figure 2 B). For the
nonuniform
dumping cross section with a linear slope on both sides to the feed maximum at
L/2 (Figure
2 A), arc-shaped rows of teeth are thus needed for homogenizing (Figure 2 C).
For
integration, the offset angle course must be continuous at least in sections
(cf. Figure 2, B).
As a result, the resulting formation line of the crushing teeth can be
continuously
differentiated along the entire axial extension of the roller.
[0018] A random, unequal material feed, provided it is known, can thus be
homogenized
along the rollers or rotors, respectively, by means of the crushing tooth
arrangement. Such a
blending along the rotors or rollers is meaningful, since tooth wear in the
roller center can
thus be reduced and thus a longer service life of the roller or of the rotor
can be achieved. In
addition, the material flow is increased in the edges, in which the flow is
low, and
consequently, a higher throughput is made possible.
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[0019] Each tooth of the one roller is axially offset to its corresponding
tooth on the
counter-roller, so that they can mesh with one another during the rotating of
the rollers.
[0020] In a preferred embodiment of the arc formation according to the present
invention,
the rows of teeth in the axial direction can be represented by polynomial
functions of
second (cf. Figure 4, A), third (cf. Figure 4, B) or higher degree. Especially
preferably, the
offset angles of the rows of teeth here decrease continuously up to a vertex
and have a
continuous course over the entire axial extension of the roller or of the
rotor. Unlike known
arrow formations, the vertices of the arc-shaped connecting lines do not form
any points of
discontinuity (arrow tip), such that an excess stressing of the center toothed
ring is
counteracted. With the furthermore preferred rows of teeth having a parabolic
course in the
axial direction, many real dumping cross sections can advantageously be
blended in a
simple manner, without knowledge of the exact cross section and thus favorably
along the
roller or rotor axis.
[0021] Furthermore, multiformations of the crushing tooth arrangement
according to the
present invention, whereby the rows of teeth have crushing tooth arrangements
repeating in
sections in the axial direction or offset angle course, are preferred. Thus, a
plurality of
crushing centers can be established along the roller or rotor axis and even
complicated
dumping cross sections can be homogenized. Especially preferably, such a
crushing tooth
arrangement has rows of teeth, which have wave-like courses in the axial
direction. If a
plurality of tooth formations are arranged behind one another in the axial
direction, the
multiformation forming cannot be continuously differentiated at the
transitions of the
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repeating crushing tooth arrangements. Preferably, the multiformations, apart
from these
transitions, has no further points of discontinuity.
[0022] In a, furthermore, preferred embodiment of the arc formation, the rows
of teeth of
both rollers or rotors have offset angle courses deviating from one another.
Thus, the axial
feed forces generated by the individual rollers may deviate from one another.
This makes it
possible advantageously to use various rollers, whereby, e.g., a heavily
loaded roller is
replaced after a certain service life, but the other one remains in the roller
crusher or rotor
crusher.
[0023] Also in the crushing tooth arrangement according to the present
invention, it is
necessary for a meshing of the teeth that the rows of teeth of both rollers
have an offset to
one another in the axial direction. Arc formations according to the present
invention, in
which the rows of teeth of both rollers or rotors can be made congruent by
shifting in the
axial direction by a distance da > 0 (cf. Figure 5) and reflection on an axis
of symmetry
parallel to the axis of rotation, are hence especially preferred. Thus,
crushing tooth
formations with decentering or centering action with rows of teeth, whose
vertices point
towards the crushing gap or away from it, can advantageously be achieved.
[0024] With the crushing tooth arrangement according to the present invention
it is
advantageously ensured that the rotor or roller teeth are uniformly centered,
which
increases both the service life of the teeth and the throughput of the rotor
crusher or roller
crusher.
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_
[0025] Furthermore, the wide versatility of the arc formation, which can be
used for any
conditions of tooth height h to tooth tip diameter D, i.e., both in rotor
crushers with toothed
rotors (h/D> 0.17) and in roller crushers with toothed rollers (h/D < 0.17),
is advantageous.
Arc formations can, in addition, advantageously be formed from any number of
rows of
teeth nu and toothed rings na, which have any, especially not only equal
distances from one
another. In addition, arc formations can also be used for any rotor and roller
active pairing,
e.g., from a rotor and a roller or two or more rotors and rollers with any
tooth formation in
relation to the active partner.
[0026] Furthermore, the subject of the present invention is a crushing tooth
arrangement on
the periphery of both rollers or rotors of a roller crusher or rotor crusher,
characterized in
that the rows of teeth of the rollers or rotors consist of tooth subgroups,
which are arranged
axially aligned, with at least two teeth, which are offset in an arrow-shaped
manner and are
arranged opposing one another. Here, according to the present invention, each
tooth is
offset axially to its corresponding tooth on the counter-roller, so that they
can mesh with
one another during the rotation of the rollers (polygonal formation).
[0027] The rows of teeth here are each formed from at least three tooth
subgroups, whereby
the simplest arrow-shaped offset arrangement is that the outer tooth subgroups
in the roller
or rotor unwinding in the axial direction are positioned closer in the
direction of the
crushing gap than the center tooth subgroup. If the row of teeth consists of
more than three
tooth subgroups, the axially outermost tooth subgroups in the roller or rotor
unwinding in
each case are positioned in the radial direction closest to the crushing gap.
This radial
distance then increases tooth subgroup for tooth subgroup, whereby the tooth
subgroup
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_
forming an "arrow tip" in the roller or rotor unwinding has the greatest
distance to the
crushing gap. If the row of teeth of this "arrow tip" has the same offset
angle on both sides
in the direction of the next tooth subgroups, corresponding tooth subgroups in
the "arrow
flanks" each occupy the same radial positions.
[0028] A rotor or roller pairing with these crushing tooth arrangements with
the rows of
teeth arranged in opposite directions advantageously forms a polygonal
crushing space for
penetrating and crushing large chunks of material in the unwinding (cf. Figure
6, B).
Because of the dependence of the draw-in behavior on the primary crushing
space forming
between the teeth above the rotors or rollers, this crushing tooth arrangement
brings about
an optimized draw-in behavior, especially for large and hard chunks. In
addition, a more
uniform load can be achieved during crushing, since fewer teeth mesh at the
same time.
Furthermore, the polygonal formation according to the present invention
advantageously
reduces the risk of blockage during the crushing operation because of the
offset of the tooth
subgroups.
[0029] In a preferred embodiment of the polygonal formation, the row of teeth
from the
"arrow tip" has different offset angles in the direction of the next tooth
subgroups or
between two corresponding tooth subgroups of both "arrow flanks" (cf. Figure
7, A). Then,
corresponding tooth subgroups in both arrow flanks of a row of teeth occupy
different
radial positions in each case. Consequently, it is advantageously prevented
that elongated
oversize uncrushed between the rows of teeth slips through. Furthermore,
consequently, the
number of teeth meshing with the material to be crushed at the same time can
advantageously be further reduced.
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[0030] In a preferred embodiment of the crushing tooth arrangement, the tooth
subgroups
are pairs of teeth or a set of three teeth. Also preferably, the number of
crushing teeth
between the individual tooth subgroups varies. Consequently, even complicated
polygonal
crushing spaces can be formed, which can be advantageously adapted to a
crushing picture
frequently occurring in a certain type of rock.
[0031] A polygonal formation, in which the rows of teeth have multiple tooth
subgroups
offset to one another in an arrow-shaped manner, is also preferred.
Consequently, a
plurality of crushing zones can advantageously be created along the roller or
rotor length
(cf. Figure 8, A).
[0032] The polygonal formations according to the present invention are
advantageously
widely versatile, especially for any conditions of tooth height h to tooth tip
diameter D, i.e.,
both in rotor crushers with toothed rotors (h/D> 0.17) and in roller crushers
with toothed
rollers (h/D < 0.17), for any number of rows of teeth nu and toothed rings na,
which have
any, especially not only equal, distances from one another and for any rotor
or roller active
pairings from a rotor and a roller or two or more rotors and rollers with
tooth formation in
relation to the active partner.
[0033] The present invention is explained in detail below based on a plurality
of exemplary
embodiments as well as figures without being limited to these examples. The
various
features of novelty which characterize the invention are pointed out with
particularity in the
claims annexed to and forming part of this disclosure. For a better
understanding of the
invention, its operating advantages and specific objects attained by its uses,
reference is
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=
made to the accompanying drawings and descriptive manner in which preferred
embodiments of the invention are illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] In the drawings,
[0035] Figure 1 shows the roller unwinding of a roller with plotted spiral
formation (a),
arrow formation (b), multispiral formation (c) or "alignment formation" (d),
as well as
offset angle 7, circumference pitch tu and axial pitch ta;
[0036] Figure 2 (A) shows the dumping height of an idealized (5) as well as of
a real (6)
dumping cross section plotted against the roller or feeder width under a
dumping angle with
a dumping height maximum at L/2; (B) shows the axial mass flow plotted against
the roller
width for blending or homogenizing the idealized (7) as well as the real (8)
dumping cross
section; (C) shows the roller unwinding with the row of teeth needed for
homogenizing the
idealized dumping cross section with alignment formation (9) as well as the
row of teeth
needed for homogenizing the real dumping cross section with arc formation
(10);
[0037] Figure 3 shows an isometric 3D view of a roller (A) as well as the
related roller
unwinding of an arc formation (10) (B);
[0038] Figure 4 shows an arc formation with formation lines of a polynomial
function of
second (A) and third (B) order;
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-
[0039] Figure 5 shows the roller unwindings of a decentering (A) and of a
centering arc
formation (B);
[0040] Figure 6 shows an isometric 3D view of a roller (A) as well as the
related roller
unwinding with polygonal formation (11) (B);
100411 Figure 7 shows the roller unwindings of a polygonal formation with
unequal (A)
and equal (B) offset angle between the tooth subgroups; and
[0042] Figure 8 shows the roller unwinding of a multipolygonal formation with
two
crushing spaces (A) and a polygonal formation with various tooth subgroups
(B).
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0043] A crushing roller with an arc formation 10 according to the present
invention is
shown in Figure 3 in a 3D view in cavalier projection as well as in a roller
unwinding.
[0044] The arc formations shown as examples in Figure 4 include an arc
formation with
formation lines of a polynomial function of second (A) and third (B) order.
Advantageously, the arc fon-nations can be shown by polynomial functions of
any order,
since these can always be continuously differentiated and rule out points of
discontinuity,
as they occur in case of the arrow formation at the arrow tip.
[0045] Figure 5 shows arc formations with decentering (A) or centering (B) arc
segments,
which point towards the crushing gap or away from it. In case of arcs pointing
in the
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-
direction of the crushing gap, the material is conducted to the rotor/roller
wall (decentering)
and otherwise to the center (centering).
[0046] It is also possible to connect in series a plurality of arc formations
in a multiarc
formation within a row of teeth in a wave-like manner.
[0047] A crushing roller with a polygonal formation 11 according to the
present invention
with a polygon-shaped crushing space 12 is shown in Figure 6 in an isometric
3D view as
well as in a roller unwinding.
[0048] The polygonal formations shown as examples, furthermore, in Figure 7
include
those with equal (Figure 7 B) and unequal (Figure 7 A) offset angle between
the tooth
subgroups as well as polygonal formation with two 4 (Figures 7, 8) and three
13 (Figures 6,
8) teeth per tooth subgroup. The number of teeth per tooth subgroup can, in
addition, vary
within a rotor or a roller or in relation to the counter-rotor or to the
counter-roller (Figure 8,
B). Finally, it is also possible that a plurality of polygonal formations are
series connected
(multipolygonal formation) within a row of teeth and consequently form a
plurality of
crushing spaces 12 (Figure 8, A).
[0049] While specific embodiments of the invention have been shown and
described in
detail to illustrate the application of the principles of the invention, it
will be understood
that the invention may be embodied otherwise without departing from such
principles.
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List of Reference Numbers
1 Row of teeth
2 Toothed ring
3 Crushing tooth (tip)
4 Pair of teeth
5 Idealized dumping cross section
6 Real dumping cross section under a dumping angle
7 Axial mass flow needed for homogenizing the idealized dumping cross
section
8 Axial mass flow or offset angle course needed for homogenizing the
real dumping
cross section
9 Row of teeth needed for homogenizing the idealized dumping cross
section
(corresponds to alignment formation)
10 Row of teeth needed for homogenizing the real dumping cross section
(corresponds
to arc formation)
11 Polygonal formation
12 Polygon-shaped primary crushing space
13 Tooth triple
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