Abstrict The invention relates to a multi-roller crusher for the comminuting
of mineral mill-feed, whereby the crushing rollers are provided
with crushing teeth, extending in the circumferential and longitudinal
axial directions. Viewed in plan, the crushing teeth are arranged
on each crushing roller such that several serial crushing teeth
groups are formed behind each other, the imagined connection lines
of which run successively at an inclined angle to the plan (1',2')
of each crushing roller outer edge in the direction of the crushing
roller centre.
Claims 1. Multi-roller crusher for comminuting mineral material to be
crushed, the crushing rollers (12) being provided with radially
projecting crushing teeth (33',44'), extending both in the circumferential
and longitudinal axial directions, characterised in that when viewing
the developed view (1',2') of each crushing roller (12) in plan
view the crushing teeth (33',44') are so arranged that they form
a plurality of successive crushing tooth groups (A,B,C,D), whose
imaginary connection lines (55',66') at a presettable angle of
inclination in relation to the developed view (1',2'), extend towards
one another from the respective outer edge (1a,2a,1b,2b) of the
crushing roller in the direction of the crushing roller centre (X,Y).
2. Multi-roller crusher according to claim 1 characterised in
that the imaginary connection lines (55',66') of the individual
crushing tooth groups (A,B,C,D) are straight lines.
3. Multi-roller crusher according to claim 1 characterised in
that the imaginary connection lines (55',66') of the individual
crushing tooth groups (A,B,C,D) are curves with presettable curvature.
4. Multi-roller crusher according to any one of claims 1 to 3
characterised in that the individual crushing tooth groups (A,B,C,D)
of each crushing roller (12) are arranged essentially in mirror-image
like fashion in relation to one another.
5. Multi-roller crusher according to any one of claims 1 to 4
characterised in that the imaginary connection lines (55',66')
of the crushing tooth groups (A,B,C,D) of each crushing roller (12),
in relation to the developed view (1',2'), are so oriented towards
one another that in the case of a twin-roller crusher (10) arrows
are formed, which are oriented towards one another.
Description [0001] The invention relates to a multi-roller crusher for comminuting
mineral material to be crushed, the crushing rollers being provided
with radially projecting crushing teeth, extending both in the circumferential
and longitudinal axial directions.
[0002] The practically viable methods of comminution differ by
the type of stress or deformation of the particles to be comminuted
in the crushing chamber. When stressing the particles between two
roller surfaces, pressure, shearing and tensile stresses are generated
in the particles. The design of the roller surface as well as the
rate of rotation determine the type of stress and the intensity.
[0003] U.S. Pat. No. specification 3240436 describes a crushing
apparatus for solid materials. In this case glass products, such
as television tubes or the like are regarded as solid materials.
[0004] The counter-rotating crushing rollers are driven synchronously
by way of a joint drive mechanism and comprise crushing teeth, provided
in the form of annular gears and arranged in the peripheral and
longitudinal axial directions. The cross-section through each crushing
roller shows that a plurality of crushing teeth per annular gear
exists so that in the region where the individual crushing teeth
of the two crushing rollers comb with one another relatively small
crushing chambers are formed in the entry region above the crushing
rollers. It is shown that even relatively large glass products may
be gripped by the teeth and are pre-crushed in the course of a first
crushing process. As the crushing gap of the counter-rotating crushing
rollers further decreases, a second, subsequent comminution is performed.
[0005] EP-B 0 167 178 describes a mineral crusher comprising two
crushing rollers, each of them equipped with a number of mineral
crusher teeth projecting radially from the roller, the teeth on
each roller being arranged in groups, extending in peripheral direction,
spaced axially along the roller, the groups of teeth extending in
peripheral direction being so arranged on a roller that they are
positioned between adjoining groups of teeth of the other roller,
extending in the peripheral direction and being axially spaced apart
from them, so that in the event of counter-rotation of the rollers
the teeth of the individual groups pass between two axially spaced
teeth in adjoining groups of teeth on the other roller, seizing
in the course thereof mineral lumps between one another, effecting
the breaking up or crushing of the said lumps. The teeth of each
roller are so arranged in relation to one another and are of such
size and shape that they define a number of discrete, peripherally
spaced, spiral or helical configurations extending along the roller.
Each roller includes therefore tooth formations extending spirally
from one end face to the other, in which context the spiral shape
may be present in the same or in the opposite direction. The object
and purpose of the spiral or helical configuration of the crushing
teeth is based on transporting the material to be comminuted in
the longitudinal direction of the crushing rollers and in comminuting
the former during transport. However, an arrangement of the spiral
or helical tooth formation in the same direction would in this case
be non-sensical, as no defined transport can be performed. This
is only possible when arranged counter-directionally.
[0006] A mineral crusher designed in this manner comprises relatively
few teeth per annular gear, viewed in peripheral direction, so that
with counter-rotating rollers a larger crushing chamber is formed
already, serving to comminute larger lumps as well. However, it
is a drawback of this mineral crusher that the material to be crushed
must be fed essentially from the end face side in order to exploit
the transport effect, thereby causing various conditions of wear
even when considering the transport of the material in the longitudinal
direction of the rollers.
[0007] If the material were to be fed elsewhere than at the end
face, transport would take place, but it would not be optimal and
it would be undefined.
[0008] The subject of the invention relates to the state of the
art as established by EP 0 167 178 i.e. by a slow running double
roller crusher. Such machines are used both for the comminution
of medium-hard rock as well as for materials with a tendency to
cake, i.e. brown and hard coal, limestone, clay marl and similar
raw materials. Parallel and counter-rotating crusher rollers are
equipped--as set out in the characterising part of the first patent
claim--with crushing teeth, the size, shape and configuration of
which define, during the interaction of both rollers, a crushing
chamber, ensuring the required quality of the discharge particle
size and the throughput performance during comminution.
[0009] It is an object of the invention to optimise the multi-roller
crusher described in the characterising part of the first patent
claim in such a manner that, in contrast to EP 0 176178 due to
the formation of simultaneously effective primary crushing chambers
substantially more large-grained lumps may also be comminuted parallel
and effectively in less time, in order, thereby, to attain an increase
of the effective comminution output. Wear should occur uniformly
across the length of the roller, with regard to the serviceable
life of the multi-roller crusher.
[0010] This object is attained in that when viewing the developed
view of each crushing roller in plan view, the crushing teeth are
arranged on each crushing roller such that they form a plurality
of successive crushing teeth groups, the imaginary connection lines
of which, at a presettable angle of inclination in relation to the
plan view, extend towards one another from each crushing roller
outer edge in the direction of the crushing roller centre.
[0011] Advantageous further developments of the object of the invention
are apparent from the subsidiary claims.
[0012] The subject of the invention relates therefore to a comminuting
apparatus, whose crushing rollers are equipped with a small number
of large tooth formations, viewed over the periphery. The ratio
between the outer diameter of the roller and the tooth height should
in this case be less than 5:1 in which context the number of teeth,
seen in the peripheral direction of each crushing roller, should
be small, e.g. limited to nine teeth.
[0013] The fewer teeth are present over the periphery, uniformly
spaced from the centre, and over the outer diameter of the crusher
rollers and the lower the peripheral velocity and therefore the
tooth engagement frequency, the more aggressively the roller surface
acts on the material to be fed, ensuring effective material intake.
Because of the small basic diameter of the crushing rollers in relation
to the centre distance, the tooth height and an axial tooth separation,
in the case of this type of crushing chamber design, relatively
large free spaces are created between the adjoining and opposite
crushing teeth in the region between the crushing rollers. In particular,
due to the mutually facing arrow configuration, viewed in the longitudinal
direction of the rollers, two successive primary crushing chambers
of approximately the same size are formed. The person skilled in
the art considers the continuous formation of deep three-dimensional
troughs for the entry of large material lumps on the roller surfaces
as primary crushing chambers.
[0014] The actual comminution process of larger material lumps
commences in this case with positive material feeding. It is characterised
in that the material lumps are seized between two or more corresponding
crushing teeth of the crushing rollers and undergo a first size
reduction. With further rotation of the crushing rollers the combing
of the corresponding teeth formations brings about the formation
of secondary crushing chambers, in which the pre-crushed or smaller
material is clamped and is locally stressed under bending and shearing
action. In this step the comminution is performed between the crushing
teeth diameter and the basic diameter of the crushing rollers, or,
respectively, between the tooth front and the tooth back of the
opposing crushing roller.
[0015] To that extent the type of comminution is to be considered
analogous to that described in EP 0 167 178. However, in contrast
to the state of the art, in the sense of momentary views taken over
the length of the roller, large intake regions are brought about
either simultaneously one behind the other or continuously forming
anew, so that in this case, contrary to the state of the art, a
substantially higher portion of coarse material may be pre-crushed,
which considerably increases the effective comminution output. In
view of the fact that, contrary to the state of the art, material
transport is now brought about on both sides, intake of the material
to be crushed may now take place centrally from above, i.e. directly
into the developing larger crushing regions. Wear of the multi-roller
crusher according to the invention, viewed over its length, is substantially
more uniform in comparison with the state of the art, which may
also increase the useful life.
[0016] In addition, subsequent comminution may optionally take
place below the central crushing gap in that a crusher beam, known
per se is provided, combining the function of an anvil or comb.
[0017] Essential factors for effective comminution with high throughput
performance by reducing the comminution time for large material
lumps are seen in the following points
[0018] Peripheral velocity
[0019] Tooth configuration or distribution
[0020] Tooth arrangement
[0021] Positioning of rotor
[0022] In the developed view the successively arranged crushing
tooth formations comprise, as imaginary connection lines, straight
lines or bends with predeterminable curvature. However, an essential
difference in contrast to the state of the art according to EP 0
17 178 is that for each crushing roller successive mutually facing
crushing tooth groups are formed, which ideally, i.e. in the case
of a rectilinearly proceeding imaginary connection line, result
in arrows oriented towards or away from one another.
[0023] The uniform crushing tooth formations over the periphery
(annular gear) in the case of the multi-roller crusher according
to the invention are arranged axially in relation to one another
on a crushing roller at a particular offset-angle, so that, viewed
spatially, two counter-oriented tooth rows are formed, which in
the event of an uneven number of annular gears have their vertex
in the region of the central annular gear of each crushing roller.
In the event of an even number of annular gears there exists no
central annular gear, so that the vertex will be formed differently.
The corresponding opposite crushing roller is equipped with the
same tooth arrangement, viewed over its length. In plan view onto
the crushing rollers in operation an arrow-like configuration extending
in opposite direction thus comes about, subdividing the overall
roller length into two large regions of about the same size.
[0024] A further development of the invention may provide that
the imaginary connection lines of the crushing teeth of each crushing
roller are provided in relation to one another appropriately set
off in relation to one another. In this particular arrangement the
uniform crushing tooth formations are arranged axially in relation
to one another on a crushing roller at a particular offset-angle
over the periphery (annular gear), such that when viewed spatially,
two rows of teeth are formed facing in opposite directions, which,
offset by a predeterminable angle of circumferential pitch, extend
towards one another. The matching opposite roller is equipped with
the same tooth arrangement, viewed over the roller length. In practical
use, when viewed in plan view of the crushing rollers, an offset
arrow configuration is brought about extending counter-directionally,
subdividing the overall roller length into two regions of approximately
equal size.
[0025] This arrangement differs from the first one mentioned above
in that the intake regions developing during operation in the course
of combing of the counter-rotating crusher rollers are not formed
simultaneously, but successively. By way of this configuration the
object of a continuous comminution process/force concentration may
even be realised in the case of smaller crushing roller lengths
comprising a smaller number of teeth/circumference.
[0026] Therefore, in contrast to the state of the art, a continuous
formation of a plurality of deep, three-dimensional, primary crushing
chambers is brought about for the simultaneous entry of large material
lumps.
[0027] For the development of primary crushing chambers crushing
rollers are advantageous, which rotate approximately synchronously.
This is brought about by mechanically coupling the crushing rollers,
but has to be regarded as complex, since the crusher housing corresponds
to the gear housing. In this context a double or single drive mechanism
may be used. In order to realise this approximately synchronous
roller rotation without mechanical connection, it is possible to
equip both rollers with independent drive means and to provide them,
for example, with a master slave control, permitting precise roller
timing.
[0028] A further parameter for optimising the primary crushing
chamber-design is seen in driving the crushing rollers asynchronously.
In this case an independent drive means may be assigned to each
crushing roller or a single drive mechanism comprising a mechanical
step-down gear unit may likewise be employed. The optimal differential
velocity of the crushing rollers for a high incidence of primary
crushing space formation may, for example, be controlled or set
by a frequency converter or hydraulic motor. The optimal differential
velocity depends in this case on the process-technological task
to be completed and the number of teeth over the circumference.
[0029] Both in the case of the advantageous arrow-shaped configuration
as well as in the case of the crushing tooth groups, provided in
an offset manner in relation to one another, a distribution function
is performed on both sides from the centre of the crushing chamber
in order to exploit the overall width of the crushing roller by
axial force components, especially in the case of larger sized material
lumps. The material is fed to the comminution apparatus, controlled
by a feeding conveyor, in which context the feed direction may be
transverse to the longitudinal direction of the rollers. The point
of impact of the discharge parabola may be set between the counter-rotating
crushing rollers as target-oriented as possible. This arrangement
avoids power--and wear-intensive deflecting and lifting of the material
flow. In particular, the fine content in the feed material may be
put through directly and with the lowest resistance and dwell time
possible, using as large as possible a passage cross-section over
the length of the roller.
[0030] The subject of the invention is shown by way of a working
example in the drawing and is described as follows. There is/are
shown in
[0031] FIGS. 1 and 2 schematic diagrams of counter-rotating crushing
rollers of a multi-roller crusher, not shown in detail, as well
as their developed views
[0032] FIGS. 3 and 4 schematic diagrams of alternative embodiments
of crushing rollers as well as their developed views
[0033] FIG. 5 a plan view of the installed crushing rollers according
to FIG. 1 and 2
[0034] FIG. 6 a side elevation of the installed crushing rollers
according to FIG. 1 and 2
[0035] FIGS. 7 to 9 different spatial illustrations (according
to FIGS. 1 and 2) of different momentary views for generating enlarged,
successive crushing chamber regions
[0036] FIGS. 10 and 11 schematic diagrams of tooth formations on
crushing rollers as an alternative to FIGS. 1 to 4
[0037] FIGS. 12 to 14 different spatial illustrations (according
to FIGS. 10 and 11) of different momentary view for generating enlarged,
successive crushing chamber regions
[0038] FIG. 15 the developed view of an arrow-shaped tooth formation
with an even number of annular gears and different pitches
[0039] FIG. 16 the developed view of an arrow-shaped tooth formation
with an even number of annular gears and even pitch
[0040] FIG. 17 the developed view of a curve-like tooth formation
[0041] FIGS. 18 and 19 momentary views during asynchronous operation
of the crushing rollers forming primary and secondary crushing spaces
[0042] In the form of schematic diagrams FIGS. 1 and 2 show counter-rotating
crushing rollers 12 of a multi-roller crusher not shown in detail.
FIG. 1 shows the crushing rollers 12 in their normal state, while
FIG. 2 illustrates the crushing rollers 12 in their developed view
1',2'. The indicated dots define crushing teeth 33',44'. It is
apparent both from the crushing rollers 12 shown in FIG. 1 as well
as from their developed view 1',2' that the imaginary lines 55',66'
interconnecting the crushing teeth 33',44' extend on each crushing
roller 12 in such a manner that successive arrows are formed. The
crushing teeth 33',44' of each crushing roller 12 form crushing
tooth groups A,B,C,D, in which case the crushing teeth 33',44'
of each crushing tooth group A,B,C,D extend from the respective
outer edge 1a,2a,1b,2b of the crushing roller in the direction of
the centre X-Y of the crushing roller. The uniform crushing tooth
formations over the circumference (annular gear) are in this crushing
roller arrangement disposed axially in relation to one another on
the crushing roller 1 at a special offset angle, such that, when
viewed spatially, two rows of teeth are formed facing in opposite
directions, having their vertex in the region of the central annular
gear 7 of the crushing roller 1. The corresponding opposite crushing
roller 2 comprises the same tooth arrangement, viewed over the length
of the roller, in which case the tooth rows 66' (imaginary connection
lines) have their vertex in the region of the associated central
annular gear 7'. Viewing the crushing rollers 12 or their developed
views 1',2' in plan view, a counter-directional arrow configuration
AB;CD thus forms, dividing the overall roller length into two uniform
regions, as shown in more detail in FIGS. 7 to 11. In FIGS. 1 and
2 the arrows formed in this manner are directed towards one another.
In the examples the imaginary connection lines 55',66' are rectilinear,
while curved designs of the protection region are likewise included
(FIG. 17), without departing from the arrow configuration.
[0043] FIGS. 3 and 4 show an alternative to FIGS. 1 and 2 in which
case the imaginary connection lines 55' as well as 66' are likewise
so arranged in relation to one another that arrows AB;CD directed
away from one another are formed. The uniform arrangement of the
crushing teeth 33',44', viewed over the circumference (annular
gear), results in two counter-oriented rows of teeth 55',66',
viewed spatially, having their vertexes in the region of the central
annular gear 77' of each crushing roller 12 or, respectively
its developed view 1',2'. For the remainder, the structure of the
crushing tooth groups A,B,C,D is be considered analogous to that
according to FIGS. 1 and 2.
[0044] FIG. 5 shows the plan view of a multi-roller crusher 10
according to FIGS. 1 and 2. Identical components are denoted by
identical reference numerals. The crushing rollers 12 can be seen
housed inside a housing 11. The crushing rollers 12 are to be driven
in counter-direction to one another (see arrows). Annular gears
1213 are apparent, to which the crushing teeth 34 are replaceably
fitted. FIG. 5 is a momentary view of successively positioned, continuously
repetitive crushing chambers, in which context in the present example
the primary crushing chamber B1 can be seen, formed by the imaginary
connection line 56 extending along the crushing teeth 34.
[0045] FIG. 6 shows a side elevation of the multi-roller crusher
10 where the annular gears 1213 carrying the crushing teeth 34
can be seen with the crushing teeth 34 arranged in offset relationship
to one another when viewed in the longitudinal direction of the
crushing rollers 12. Furthermore the housing 11 surrounding the
crushing rollers 12 can be seen. In the present example, each crushing
roller 12 comprising 4 crushing teeth 34 per annular gear 1213
so that the arrow-shaped profile shown in FIGS. 1/2; 3/4 is brought
about.
[0046] FIGS. 7 to 9 show different perspective illustrations of
momentary views of the multi-roller crusher 10 with an arrow-shaped
tooth arrangement. This is done with regard to the continuously
changing crushing chambers B1 B2 B3. In this case as well, the
same reference numerals denote identical components. The two crushing
rollers 12 are shown, the annular gears 1213 positioned thereon
as well as the crushing teeth 33',44' provided thereon. The crushing
rollers 12 are arranged inside the housing 11 in which context
the crushing teeth 33',44' may be passed between formations 1415
on the side of the casing. The formations 1415 have a particular
configuration and are designed like a comb. It is their function
to deflect the material fed to the crushing chamber directly to
the central crushing gap, without causing the material to be raised
in counter flow. Moreover, they serve as means to avoid oversized
particles, since they ensure compliance with the separation size
diameter in the side regions. In addition, they exercise a stripping
function, in order to protect the space between the annular gears
from caking materials. The parameter to be allocated to the crushing
spaces B1 B2 B3 is recognisable by way of the imaginary connection
lines 55',66' and illustrates--as already mentioned--merely a
momentary view.
[0047] FIG. 7 shows an opened-up design of the roller surface,
i.e. a deep three-dimensional trough B1 for receiving large material
lumps entering there. As a result of the arrow-shaped arrangement
of the crushing teeth 33',44' in conjunction with the given, momentary
roller positioning (gripping position) oblong material lumps may
come to lie in the trough B1 deepening over the entire roller length
towards the centre. Because of the rebating on both sides of the
corresponding central tooth pair 77' of both crushing rollers 12
high comminution efficacy is attained. The less mutual interference
between the adjoining teeth 33',44' and the tooth pair 77' takes
place, the more results a favourable intake performance. In the
state of the art according to EP 0 167 178 a rebating exists only
on one side over the roller length of the crushing teeth. In the
course of further rotation of the crushing rollers further primary
crushing chambers B2 B3 (FIGS. 8 and 9) develop. If the material
lump in the primary crushing chamber B1 has not yet been adequately
comminuted, it is conveyed into a forced position axially towards
the exterior, defined by the respective housing side walls as well
as the crushing chambers B1 B2 and the axial force components,
exercised by the tooth formations onto the lumps. In these crushing
chambers B2 B3 the further primary comminution is performed. In
the state of the art only a single primary crushing chamber is formed
on the roller surface due to the helical arrangement of the crushing
teeth over the roller surface. Any larger sized material lumps remaining
at the end of the crushing rollers opposite the end face feeding
are therefore merely conveyed into a single forced position, formed
by the associated housing side panel. As a result of the frequency
of the developing primary crushing chambers B1-B3 the effective
primary comminution throughput is substantially increased as compared
with the state of the art. The material is transported less until
comminution takes place, resulting in faster comminution and lower
wear.
[0048] FIGS. 10 and 11 as schematic diagrams, show an alternative
embodiment of the tooth groups A,B,C,D in the region of the crushing
roller 12 as their respective developed views 1',2'. FIG. 11 shows
crushing teeth 33',44' forming successively positioned tooth groups
AB;CD, in which case the imaginary connection lines 55',66' extend
towards one another, but do not form an ideal arrow, but an offset
arrow configuration. In this example the imaginary connection lines
55',66' extend towards one another at different angles of inclination.
A profile is brought about, which may be compared approximately
to that of FIGS. 1 and 2 in which context, as an alternative to
FIGS. 3 and 4 a reversed arrangement of the crushing teeth 33',44'
is likewise conceivable.
[0049] Further momentary views, based on FIGS. 10 and 11 are shown
in FIGS. 12-14. The continuous modification of the successively
forming crushing chambers B2 B3 is shown, in which context in this
case as well identical components are denoted by identical reference
numerals.
[0050] In the examples cited in accordance with FIGS. 1 to 14 the
crushing rollers 12 are to be driven synchronously, in which case
each crushing roller 12 is provided with connected drive means,
not shown in detail, such as, for example, gear mechanisms, belts
or the like.
[0051] FIG. 15 shows the developed view 1',2' of an arrow-shaped
tooth formation with an even number of annular gears and different
pitches or angles of inclination of the imaginary connection lines
55',66' of the individual crushing teeth groups AB, CD. Except
for the different pitches of the lines 55',66' interconnecting
the crushing teeth 33',44', this illustration corresponds approximately
to that of FIG. 2.
[0052] FIG. 16 shows the developed view 1',2' of an arrow-shaped
tooth arrangement with an even number of annular gears and even
pitches or angles of inclination of the imaginary connection lines
55',66' and corresponds approximately to that according to FIG.
2.
[0053] FIG. 17 shows the developed view 1',2' of the crushing teeth
33',44' arranged on a curve segment (imaginary connection line
55',66') as an alternative to FIGS. 2415 and 16.
[0054] The person skilled in the art will select the type and arrangement
of the crushing teeth 33',44' on the crushing rollers 12 as a
function of the respective application.
[0055] FIGS. 18 and 19 are momentary views during an asynchronous
operation of the crushing rollers 12. In this example, the crushing
rollers 12 dispose of independent drive means, such as gears, not
shown in detail. Setting of the differential velocity of the two
crushing rollers 12 may, for example, be regulated by a frequency
converter. The primary crushing chamber B2 can be seen. Further
indicated is in each case a secondary crushing chamber B4 developing
in the narrowing crushing gap of the counter-rotating crushing rollers
12 in the course of the further intake of the pre-crushed material.
[0056] As a result of the alternative arrangement according to
the invention of crushing teeth 33',44' in the selected configurations,
the following technical advantages are attained:
[0057] Undelayed material intake of relatively large material lumps
is performed by the permanent, continuous provision of one or more
intake possibilities B1B2B3 viewed over the entire length of
the crushing rollers 12.
[0058] Because of the continuously closing, narrowing crushing
chambers B1B2B3 the material, in the course of combing of the
counter-rotating crushing rollers 12 is stressed locally in respect
of bending and shearing as a result of the introduction of forces
via the crushing teeth 33',44' and not compressively.
[0059] A uniformly progressing comminution is attained in the maximally
three stress zones (primary, secondary, and, where applicable, tertiary
comminution), resulting in a division of the crushing roller length
into regions, in which, viewed in the peripheral direction, the
primary (B1-B3), secondary (B4) and, optionally, tertiary comminution
is performed. There are no dividing lines between the transition
points in this case. As the greatest crushing forces occur during
the primary size reduction, the installed provision for torque for
comminution may be lower, since there is a concentration of forces
onto few, operating tooth pairs 34;3',4'. The stress on all machine
elements, in particular the drive mechanism, is lessened and with
lower impact load. The overall stress dynamics are rendered more
even.
[0060] As a result of the particular crushing roller design and
the additional comminution by utilising a crushing comb in conjunction
with the stress on materials resulting therefrom, the gap width
being the defined smallest spacing of the roller surfaces as well
as of the tooth spacings to one another may be substantially greater
than in conventional roller crushers, in order to ensure the desired
end particle size.
[0061] Material transport on the crushing rollers, i.e. bringing
about axial force components on the material, in particular large
material lumps, in order to avoid grooving and, consequently, jamming
of large material lumps. The material remains in motion at all times
until a suitable intake and roller position comes about.
[0062] Depending on the crushing chamber design B1B2B3 determined
by the roller design including the tooth configuration and number
over the circumference, arrangement, rotor position or use of a
crusher beam, the particle size distribution of the final particle
may be set.
[0063] As a result of the tooth arrangement according to the invention,
contemplated in momentary views, a continuous formation of deep
three-dimensional, primary crushing chambers B1B2B3 for the penetration
of large material lumps takes place. Because of the arrow-shaped
or arrow-like configuration in conjunction with--if required--a
synchronised crusher roller positioning in gripping position, the
simultaneous (or successive) formation of intake regions B1B2B3
on the roller surface is brought about. In particular, the efficiency
of the corresponding central tooth pair 77' of both crushing rollers
12 is improved, as oblong material lumps may come to lie in the
recess(es) B1B2B3 deepening over the entire crushing roller length
towards the centre. The axial offset angle of the annular gears
1213 determines the pitch of the counter-oriented imaginary connection
lines 55',66' and is matched to the distribution on the periphery,
i.e. number of crushing teeth 33',44'. An arrangement is optimal,
which proceeds continuously, i.e. after passing through the first
arrow the central tooth pair 77' engages as start of the next following
arrow, in order to ensure a continuous crushing operation.
[0064] The arrow configuration, offset in opposite direction, described
in FIGS. 10 and 11 differs from the arrow configurations discussed
in FIGS. 1 to 4 in such a manner that the developing intake regions
B2 B3 are not formed simultaneously during combing of the counter-rotating
crushing rollers 12 but successively, i.e. once the one roller
half has passed through the primary intake region B2 the primary
engagement of the other roller half takes place continuously. With
this design the object of a continuous comminution process/force
concentration may even be realised in the case of short roller lengths
having a low number of teeth in relation to the circumference. As
a result of the serial succession of effects, the pitch of the imaginary
connection lines 55',66' may be reduced by half, as compared to
the arrangement illustrated in FIGS. 1 to 4. This permits the provision
of larger intake chambers B2B3.
[0065] Both arrangements necessitate a distribution function to
both sides from the centre of the crushing chamber in order to exploit
the entire roller width by axial force components, especially in
the case of relatively large material lumps. The material is fed
to the multi-roller crusher, controlled normally via a feed conveyor,
in which context the feed direction may be transverse to the longitudinal
direction of the roller. The point of impact of the discharge parabola
may be set between the counter-rotating crushing rollers 12 as
target-oriented as possible. This arrangement avoids power- and
wear-intensive deflecting of the material flow, while, in particular,
the fines content in the feed material may be put through directly
and with the lowest resistance and dwell time possible, using as
large as possible a passage cross-section over the length of the
roller. |