WO2004002629A1

WO2004002629A1 - Collision member with collision surface relief

Info

Publication number: WO2004002629A1
Application number: PCT/NL2003/000188
Authority: WO
Inventors: Johannes Petrus Andreas Josephus Van Der Zanden
Original assignee: Van Der Zanden, Rosemarie, Johanna
Priority date: 2002-06-28
Filing date: 2003-03-12
Publication date: 2004-01-08
Also published as: ATE329692T1; AU2003221266A1; EP1583608B1; EP1583608A1; NL1020957C2; DE60306204D1; WO2004002629A9; ES2266796T3; DE60306204T2

Abstract

The method and the device according to the invention relates to a stator and an armoured ring which are combined to give a stationary annular collision member that is arranged around the rotor, as it were in the form of a stator that is provided all round along the inside, which faces the axis of rotation, with protruding collision surface reliefs, each of which is provided with at least one collision surface that is arranged transversely in the ejection stream that the material describes when it is propelled outwards from the rotor.

Description

COLL SON MEMBER WITH COLLISION SURFACE RELIEF

FIELD OF THE INVENTION

The invention relates to the field of the acceleration of material, in particular a stream of granular or particulate material, with the aid of centrifugal force, with, in particular, the aim of causing the accelerated grains or particles to collide with a stationary collision member at such a velocity that they break.

BACKGROUND TO THE INVENTION

According to a known technique the movement of a stream of material can be accelerated with the aid of centrifugal force. With this technique the material is fed onto the central part (the circular feed surface of a receiving and distributing member) of a rapidly rotating rotor and is then picked up by one or more accelerator members which are carried by said rotor with the aid of a support member and are provided with an acceleration surface that extends from the outer edge of said feed surface in the direction of the outer edge of the rotor between the central feed and the take-off end of said accelerator member. The fed material is picked up from the receiving and distributing member by the central feed, then accelerated along the acceleration surface under the influence of centrifugal force and thereafter, when the accelerated material leaves the accelerator member at the location of said take-off end, is propelled outwards at high velocity. Viewed from a stationary standpoint, after it leaves the accelerator member, the material moves at virtually constant velocity along a virtually straight stream that is directed forwards. Viewed from a standpoint moving with the accelerator member, after it leaves the accelerator member, the material moves in a spiral stream that is directed backwards, viewed in the direction of rotation; during this movement the (relative) velocity increases (progressively) along said spiral path as the material moves further away from the axis of rotation.

The accelerated material can now be collected by a stationary collision member that is arranged in the straight stream that the material describes, with the aim of causing the material to break during the collision. The stationary collision member can, for example, be formed by an armoured ring that is arranged centrally around the rotor. The material strikes the stationary collision member at the velocity that it has when it leaves the rotor. The comminution process takes place during this single impact, the equipment being referred to as a single impact crusher.

In the known single impact crushers the material is accelerated with the aid of accelerator members that are carried by a rotor and are provided with acceleration surfaces that are directed radially (or forwards or backwards) and propelled outwards at high velocity - at a take-off angle («) of 35° to 40° - onto a stationary collision member in the form of an armoured ring made up of anvil elements, which is arranged around the rotor a relatively short distance away. The collision surfaces of the stationary collision member are in general so arranged that the collision with said stationary collision member as far as possible takes place perpendicularly. The consequence of the specific arrangement of the collision surfaces of the individual anvil elements that is necessary for this - at an angle - is that the armoured ring as a whole has a sort of knurled shape with projecting points. Equipment of this type with a non-symmetrical configuration that is operational in one direction of rotation is disclosed in US 2 991 949 (Sellars), US 4 065 063 (Johnson), US 5 184784 (Rose at al.), US 5 248 101 (Rose et al.) and US 5 921 484 (Smith, J., et al.) and in a symmetrical configuration that is operational in two directions of rotation is disclosed in US 5 323 974 (Watajima) and US 5 806 774 (Vis); both known configurations are of particular importance with regard to the collision member of the invention.

It is also possible to allow material to impinge autogenously on a bed of own material. Equipment of this type is disclosed in US 4 662 571. It is also possible to allow some of the material to impinge on an armoured ring and some to impinge on a bed of own material. Equipment of this type is disclosed in US 5 639 030 (Nakayama). Equipment that can be equipped with both a (knurled) armoured ring and a bed of own material is disclosed in US 4 560 113 (Szalanski) and US 4 579 290 (Terrenzio) and PCT/NL97/00565, which was drawn up in the name of the Applicant. In the known configurations the armoured ring blocks are arranged against the outside wall of the crusher or against the outside wall of a supporting construction in which the armoured ring blocks are arranged and which supporting construction can be installed and removed as a unit with the armoured ring blocks.

The collision surfaces of the individual anvil elements of the known single impact crushers are often made straight in the horizontal plane, but can also be made curved, for example in accordance with a circle evolvent. Equipment of this type is disclosed in US 2 844 331. What is achieved by this means is that the impacts all take place at the same (perpendicular) collision angle. US 3 474 974 discloses equipment for a single impact crusher where the stationary impact surfaces in the vertical plane are oriented obliquely downwards, as a result of which the material rebounds in the downward direction after impact. What is achieved by this means is that the collision angle is more optimum, the impact of subsequent grains is less disturbed by crushed fragments from previous impacts and the crushed fragments do not rebound against the edge of the rotor (or at least do so to a lesser extent). However, the projecting points are still there and when these wear away the shape of the collision surface rapidly becomes less important. In the case of the known armoured rings the protruding relief serves for comminution and the edge behind, from which the elements protrude, for supporting the protruding elements (relief) and for the support of the collision member as such by the crusher housing. For this purpose the edge behind, and sometimes also the bottom edge and the top edge are often provided with holes, grooves or projections which act as fixing member.

Instead of allowing the material to impinge directly on a stationary collision member, it is also possible first to allow the material to impinge on the impact surface of a co-rotating impact member associated with the accelerator member, which co-rotating impact member is carried by the rotor and is arranged a greater radial distance away from the axis of rotation than is the guide member, with the impact surface oriented transversely to the spiral stream, with the aim of allowing the material to collide once before the material strikes the stationary collision member. The material strikes the co-rotating impact member (impact surface) at the (relative) velocity that the material develops along said spiral path, the material being simultaneously loaded and accelerated during the impact, with which velocity the material is then loaded for a second time when it strikes the stationary collision member. With this arrangement there is said to be a direct multiple impact crusher, which has a very much higher comminution intensity than a single impact crusher. A direct multiple impact crusher is disclosed in PCT/NL97/00565, which was drawn up in the name of the Applicant. The rotor of the direct multiple impact crusher can also be of symmetrical construction, which makes it possible to allow the rotor to operate in both directions. A device of this type is disclosed in PCT/NLOO/00668, which was drawn up in the name of the Applicant and is of particular importance with regard to the invention. The known symmetrical rotor is provided with guide members that are symmetrical with respect to a radial plane from the axis of rotation of said rotor - for example V-shaped where the point is oriented towards the axis of rotation - which symmetrical guide member is provided with two guide surfaces, one for each direction of rotation, and each guide surface is associated with the impact surface of a co-rotating impact member. In order to achieve as high a possible a probability of breakage it is of essential importance that the collision as far as possible takes place free from disturbance. The angle at which the material impinges on the armoured ring also has an effect on the probability of breakage and the same applies for the number of impacts that the material makes or has to endure and how rapidly after one another these impacts take place. The impulse forces that are generated during the collision are directly related to the take-off velocity at which the material leaves the rotor; in other words, the faster the rotor turns in a specific set-up the higher is the collision velocity and, usually, the better is the crushing result.

The collision velocity is determined by the take-off velocity and the collision angle (β) by the take-off angle (α) (and, of course, the angle at which the impact surface is arranged or at which the impact takes place). The take-off velocity is determined by the rotational velocity of the rotor and is made up of a radial velocity component and a velocity component that is oriented perpendicularly to the radial velocity component, i.e. transverse velocity component, the magnitudes of which velocity components are determined by the length, shape and positioning of the accelerator member and the coefficient of friction. The take-off angle (α) is essentially determined by the magnitudes of radial and transverse velocity components and is usually hardly influenced by the rotational velocity. If the radial and transverse velocity components are identical, the take-off angle (α) is 45°; if the radial velocity component is greater, the take-off angle ( ) increases and if the transverse velocity component is greater the take-off angle (α) decreases.

Research has shown that for the comminution of material by means of impact loading a perpendicular impact is not optimum for the majority of materials and that, depending on the specific type of material, a (much) higher probability of breakage can be achieved with a collision angle of approximately 70°, or at least between 60° and 80°. Below 65° to 60° the probability of breakage starts to decrease progressively because the collision angle becomes too flat and a glancing blow starts to develop. As a result the wear increases. Furthermore, the probability of breakage can also be appreciably increased if the material for crushing is subjected not to single impact loading but to multiple, or at least double, impact loading in rapid succession, as is the case in the known multiple impact crusher.

The straight stream along which the material moves after it has been propelled outwards from the rotor moves ever further in the radial direction, viewed from the axis of rotation, as the material moves further away from the rotor. This makes it possible to construct the armoured ring, if this is arranged a sufficient distance away from the rotor, with a smooth annular impact surface - i.e. as a stator - against which the material impinges at an angle which yields adequate probability of breakage, i.e. a collision angle of > 60° and preferably > 70°. A stationary collision member of this type is disclosed in PCT/NLO 1/00482 that was drawn up in the name of the Applicant and is of particular importance with regard to the invention and is of particular importance with regard to the collision member according to the invention.

A (knurled) armoured ring with projecting points has the advantage that the armoured ring can be arranged around the rotor blade a short radial distance away and nevertheless a sufficiently large collision angle can be achieved. As a result the crusher housing can be made compact with a small diameter. However, the projecting points have the disadvantage that these partially disturb the impacts, as a result of which an excess of particles that are too fine and too coarse are produced; however, the major disadvantage is that as the projecting points wear away an ever smoother ring starts to form that, at the short radial distance from the rotor, leads to the impacts taking place at an increasingly acute angle, as a result of which the probability of breakage decreases substantially and at a given point in time there are glancing blows, which are no longer effective. The armoured ring must therefore be replaced in good time, as a result of which a great deal (usually more than 60 - 70 %) of the wear material remains and has to be thrown away. A collision member in the form of a stator, or constructed with a smooth annular impact surface, has the advantage that the impacts are not disturbed by projecting points as is the case with an armoured ring, as a result of which the probability of breakage is not substantially affected when wear occurs along the impact surface; moreover, such an impact member is symmetrical and makes it possible to allow the rotor to rotate in two directions. However, the known stator has the disadvantage that in order to achieve an effective collision angle, > 60° and preferably 70°, the impact surface has to be arranged a large radial distance away from the axis of rotation, which leads to a large diameter of the stator, which then also has to have a certain thickness in order to achieve a practical tool life. The consequence of this is that if the crusher housing is equipped with a stator it has to be constructed with an appreciably larger diameter than when it is equipped with an armoured ring with projecting points, or collision surface relief, which, as has been stated, has to be arranged a much smaller distance from the rotor because the projecting points are otherwise not effective.

Another disadvantage of the known stationary collision member (with collision surface relief), which usually is made up of a number of individual blocks that are positioned next to one another in an annular support member, is the relatively low tensile strength of the structural material from which the block is made, which usually has a high hardness (> 60-65 Re) and is consequently brittle. The pointed collision surface relief can consequently break off or crack easily when material collides with it here at high velocity. This applies in particular for relatively harder, coarser (> 50 mm) fragments which impinge at a velocity of > 50 m sec. Moreover, the material can contain other types of foreign constituents, for example in the form of metal particles (impurities) which have passed into the feed stream and can cause severe damage. An additional problem is that when a block is (severely) damaged this affects the tool life of the entire ring. The same problem essentially arises with accelerator members (in particular co-rotating impact members) that are mounted on the rotor. A method for strengthening such hard and brittle accelerator members is disclosed in PCT/NLO 1/00482, which was drawn up in the name of the Applicant.

AIM OF THE INVENTION

The aim of the invention is, therefore, to provide a method as described above that does not have these disadvantages or at least displays these to a lesser extent. Said aim is achieved by essentially combining a stator and an armoured ring to give a stationary annular collision member that is arranged around the rotor, as it were in the form of a stator that on the inside, which faces the axis of rotation, is provided all round with protruding collision surface reliefs, each of which is provided with at least one collision surface that is arranged transversely in the ejection stream that the material describes when it is propelled outwards from the rotor. The method and device with the collision member with collision surface relief is described in detail in the appended claims, to which reference is made here.

Here material is understood to be a fragment, grain or a particle, or a stream of fragments, grains or particles, i.e. irregularly shaped (but also regularly shaped) material that usually is fed as a stream into and through the crusher, designated in general here as material or granular material.

If the radial distance between the rotor and the collision member or collision surface relief or collision surface or outer edge of the collision member is chosen well and the collision surface of the protruding collision surface relief is positioned well with respect to the straight path (ejection stream) that the material describes when it is propelled outwards from the rotor, such that the collision surface is oriented essentially transversely to the ejection stream and the collision member is arranged an adequate distance from the rotor, the collision member continues to be functional when the protruding collision surface relief starts to wear away and the collision member as it were gradually changes from an armoured ring with protruding collision surface relief to a stator with a smooth collision surface. This makes it possible to construct the collision member with the larger radial thickness and to arrange it around the axis of rotation a smaller radial distance away, which makes a smaller crusher housing possible and nevertheless yields an effective collision member with a long tool life, i.e. a compromise between a device constructed with armoured ring and a device constructed with stator. The method of the invention makes use of the fact that the direction of the movement of the material - in the ostensible, i.e. apparent, sense - changes. Specifically, when the material is propelled outwards from the rotor (which is provided with an accelerator member) at a take-off location, said material moves along an inclined straight ejection stream directed forwards, the direction of which in the apparent sense shifts increasingly in the radial direction as the grains move further away from the axis of rotation, viewed from the axis of rotation and viewed from a stationary standpoint, but the direction, of course, never becomes completely radial and is further explained in (PCT/NL01/00482), which was drawn up in the name of the Applicant.

The consequence of this is that when a smooth annular collision surface - in the form of a stator - that acts as a stationary collision member is arranged concentrically around the rotor, the collision angle at which the material strikes the collision surface of the collision member is constant all round for all grains and the magnitude of the collision angle increases as the free radial distance between the rotor and the annular collision surface increases. It is therefore possible to allow all grains from the stream of material to collide with the collision surface of the annular collision member in an essentially identical manner at a predetermined optimum collision angle, completely free from disturbance, i.e. in a completely deterministic manner.

For the majority of materials the optimum collision angle is approximately 70°, but usually may not be less than 60° because then a sort of glancing blow takes place, as a result of which the probability of breakage decreases substantially (and the wear increases substantially). The magnitude of the free radial distance between the rotor (or more accurately take-off location from which the material leaves the rotor) and the annular collision surface, required to achieve such an optimum collision angle, that is 60° to 70°, is determined by the take-off angle (α) and can be calculated with the aid of the equation:

cosα cosβ'

rl = the first radial distance from the axis of rotation to the take-off location. r3 = the second radial distance from the axis of rotation to the base circle, α = the take-off angle between the straight line having thereon the take-off location that is oriented perpendicularly to the radial line from the axis of rotation having thereon the take-off location and the straight line, from the take-off location, that is determined by the movement of said material along the straight ejection stream. β' = the base angle (in degrees) between the straight line having thereon the ejection stream and the straight line, having thereon the location where the straight line having thereon the ejection stream intersects the base circle, that is oriented perpendicularly to the straight line from the axis of rotation having thereon the location where the straight line having thereon the ejection stream intersects the base circle.

The radial distance between the take-off location and the impact location (smooth ring) - indicated as the ratio r3/rl - that is needed to achieve a base angle (β¹) of 60° and 70° respectively, against the smooth ring is:

ff angle (α) Base angle (β')

60° 70°

30° 1.73 2.53

35° 1.64 2.40

40° 1.53 2.24

45° 1.41 2.07

50° 1.29 1.77

In the case of a multiple impact crusher the take-off angle (α) is usually between 40° and 50°, depending on the configuration of the rotor. To achieve a base angle (β¹) (collision angle (β)) of 70°, the free radial distance must then be approximately equal to the diameter of the rotor. To achieve a collision angle of 60° the requisite free radial distance is appreciably less; » 50 % of the diameter of the rotor. In the case of a single impact crusher the take-off angle (α) is usually flatter, between 30° and 40°. The free radial distance then has to be taken appreciably greater, which leads to a crusher housing with a large diameter, but the acceleration surfaces can be so positioned that here again a relatively large take-off angle can be achieved. Thus, the two types of crusher can be combined with an annular collision surface (stator), but the multiple impact crusher is preferred here because the material has then already been loaded and (pre)crushed once before it impinges on the smooth armoured ring (stator).

However, the collision member according to the invention is not provided with a smooth annular collision surface. According to the method of the invention, the material that is fed onto the rotor with the aid of a feed member, accelerated in at least one step, with the aid of an accelerator unit, which accelerator unit is carried by the rotor and consists of at least one guide member that is provided with at least one guide surface that extends in the direction of the outer edge of the rotor, which accelerated material leaves the accelerator unit at a take-off location and is thrown (propelled) outwards from the rotor along an ejection stream, which take-off location is a first radial distance (rl) away from the axis of rotation, the accelerated material moving along the ejection stream in an increasingly radial direction from the axis of rotation as the material moves further away from the axis of rotation, viewed from a stationary standpoint.

The accelerator unit can consist of a guide member having a guide surface for accelerating the material on the rotor in one step or of a combination of a guide member and a co-rotating impact member that is associated with the guide member and has an impact surface for accelerating the material on the rotor in two steps.

The take-off location is the location from which the accelerated material leaves the rotor and is propelled outwards. Depending on the rotor construction, the take-off location is usually determined by the outer edge of the guide member in the case of a single impact crusher. However, if the guide surface is curved (backwards) the material can leave this guide surface before it has reached the outer edge. In the case of a multiple impact crusher the material is propelled outwards from the rotor from the co-rotating impact member. Depending on the angle at which the material strikes the co-rotating impact surface and the angle at which the co-rotating impact surface is arranged, the material can leave said co-rotating impact surface at the location where it impinges and thus rebounds immediately; however, the material can also be retained by the co-rotating impact surface following the impact and also make a guiding movement along the co-rotating impact surface. The material can then leave at the location of the outer edge of the co-rotating impact surface or from a location between the co-rotating impact location and the outer edge. The take-off location can therefore be defined in several ways but can be calculated fairly precisely and is thus predetermined. The outer edge of the accelerator member or the co-rotating impact member is often coincident with the outer edge of the rotor. To summarise, it can be stated that:

- The take-off location is a first radial distance (rl) away from the axis of rotation.

- The material ejected (propelled outwards) then collides with a stationary collision member that is a greater radial distance away from the axis of rotation than is the outer edge of the rotor and extends in an essentially regular manner around the axis of rotation;

- which collision member consists of at least one collision part that extends around the rotor:

- between, at least two radial planes from said axis of rotation, that is to say the collision member can consist of a ring (one piece), of a number of (two or more) collision parts that together form a ring or of one or more collision parts that span one or more (individual) segments; and in the plane of rotation around the rotor extends between:

- an inscribed circle having a radius (r2), the centre of which is essentially coincident with the axis of rotation, that touches the sides of the collision member on the inside, where r2 > rl, and;

- a circumscribed circle having a radius (r4), the centre of which is essentially coincident with the axis of rotation, that touches the sides of the collision member on the outside, where r4 > r2;

- with, between the inscribed circle and the circumscribed circle, an essentially imaginary base circle having a radius (r3), the centre of which is essentially coincident with the axis of rotation, that essentially divides the collision part into a ring segment and a relief segment where, r2 < r3 < r4;

- which ring segment essentially extends between (from the edge of) the base circle and (from the edge of) the circumscribed circle, and

- which relief segment is provided with at least one collision surface relief that extends in the direction of the axis of rotation and is provided with at least one collision surface that extends between (from the edge of) the base circle and (from the edge of) the inscribed circle and essentially is oriented transversely to the ejection stream,

- where:

- the third radial distance (r3) from the vertical axis of rotation to the base circle in relation to the first radial distance (rl) from the axis of rotation to the take-off location - i.e. the ratio r3/rl - is chosen at least sufficiently large that the line that is coincident with the ejection stream intersects the imaginary base circle at a base angle (β') that is equal to or greater than 60°, viewed from a stationary standpoint, the ratio r3/rl being determined by the take-off angle (a) but being at least equal to or greater than 1.70.

Essentially a collision member must be sought where both [1] the collision surfaces of the relief segment (armoured ring) are arranged at an optimum collision angle (β) and [2] the base circle where the ring segment (stator) starts also describes an optimum base angle (β') with the ejection stream. In this context it is preferable that the rotor can be rotated in two directions, for which purpose the relief segments must be made symmetrical with two collision surfaces (one for each direction of rotation). Such a symmetry doubles the tool life of the rotor and guarantees uniform wear around the stationary collision member, even if the material is not fed precisely onto the centre of the rotor. The problem is that both collision surfaces have to be properly oriented to the ejection stream, such that the collision surfaces oriented in opposing directions do not interfere with the impacts (or at least do so as little as possible). A non-optimum configuration leads to the ejection stream striking these surfaces oriented in opposing directions at a very flat angle (glancing blow), which substantially reduces the probability of breakage and accelerates wear. The invention therefore provides the option of a higher r3/rl ratio - depending on the takeoff angle (α), the desired base angle (β') and the possibly symmetrical configuration - i.e. equal to or greater than 1.75 - 1.80 - 1.85 - 1.90 - 1.95 - 2.0 - 2.25 - 2.50 and higher.

The guideline is that in the case of a symmetrical configuration the optimum r3/rl ratio is usually between 1.70 and 2.0, up to a maximum of 2.50. In the case of a non-symmetrical configuration the r3/rl ratio can be chosen to be higher, from 1.70 to 2.50. Furthermore, the "thickness" of the relief segment plays a significant role here, especially in the case of a symmetrical configuration.

The material first impinges on the collision surface relief (collision surface) and when the collision surface relief, i.e. the relief segment, wears away an essentially smooth annular collision surface is produced all round that is essentially coincident with the base circle that the ring segment describes, after which said smooth annular collision surface of said ring segment gradually wears away further until the outer edge of the collision member, which is located a fourth radial distance (r4) away from said axis of rotation that is greater than said third radial distance (r3), has been reached. The thickness of the relief segment (r3 - r2) and the thickness of the ring segment (r4 - r3) can be "freely" chosen, the guideline being that:

- the radial distance between the base and the relief edge (r3 - r2) is preferably equal to or less than the radial distance between the relief edge and the outer edge of the collision member (r4 - r3), but can also be greater; - the thickness of the ring segment (r4 - r3) can be indicated as the ratio between r4 and r3, i.e. r4/r3, which is preferably chosen to be > 1.1, but can also be chosen to be smaller, which can be necessary in the case of a symmetrical configuration.

The invention provides the option that the collision member consists of [1] a collision part that is cast as a ring (consists of one piece) and [2] two or more collision parts that together form a ring. The size of the collision parts - i.e. the segments that the collision parts span - can be the same but can also differ. The height of the various collision parts also does not have to be the same. The collision parts are provided with one or more collision surface reliefs that protrude in the direction of the axis of rotation, i.e. extend between the base circle and the inscribed circle. The shape of the collision surface relief can be point-shaped (for example triangular and V- shaped), but can also be made with truncated points (for example truncated V-shaped or trapezium-shaped) or with round "points" (even semicircular or completely circular collision parts), it being possible to combine several shapes of collision surface reliefs. The embodiment provides the option that the collision element is made with two or more collision surface reliefs which not have to be the same shape.

The individual collision parts can be placed in a holder or container - such that an annular collision member is formed - that can be placed as a complete unit with the holder in the crusher chamber, for example bearing on projections that have been fixed to the inside wall of the crusher chamber. The holder can consist of a flat disc on which the collision parts are placed, but also of a sleeve, or sleeve with disc (channel), the collision parts being placed against the inside of the sleeve wall. The collision parts can also be arranged (with no special facilities) against the inside wall of the crusher housing.

However, it is preferable that the collision member is arranged such that it is as free as possible, that is to say that there is an open (free) space between the collision member and the inside wall of the crusher housing, which space extends at least over the middle of the collision member over at least 75 % of the height of the collision member, and bears on the support member or the crusher housing only along (one of) the edges. With this arrangement the spacer member can be borne by the collision member or by the crusher housing. This open space fills with own granular material when the collision member wears through, as a result of which an autogenous layer of own material, which protects the crusher wall against wear, deposits in this space. Such an all-round "autogenous open space" is found to be extremely effective in practice when holes (slit- shaped openings) form in the collision member as a result of wear and makes it possible to utilise the wear parts as completely as possible, to more than 80 % of the volume.

The collision parts can be placed cold in contact with one another on a support member (for example a flat disc that is fixed to the crusher wall all round); the blocks then as it were clamp against one another all round and are not able to move forwards (or are able to do so only to a limited extent). However, it is preferable to "anchor" the blocks, which can be achieved in a simple manner by, for example, filling the space behind the blocks with own material when the ring has been placed in position. However, it is also possible to provide the blocks with support members along the top edge (and optionally also the bottom edge) in the form of spacer ridges that bear on the inside of the crusher wall. The blocks can also be provided with a fixing member, for example in the form of fixing projections that drop into openings in an annular disc and optionally also with a disc on top of the ring such that the blocks are clamped between two discs, it being possible to "lock" the upper ring disc, for example by the cover, but optionally also with a different type of locking mechanism. It is also possible to provide the collision parts with hooks by means of which they can be mounted, or with other types of fixing members.

The rotor usually turns about an essentially vertical axis of rotation, but the invention provides the option that the rotor rotates about an axis of rotation that is not vertical.

The invention provides the option that the collision parts are provided with a connector member by means of which the collision parts are connected to one another, for example in that they hook into one another or with the aid of other types of connector members. In this context it is preferable that the connection is made along the bottom edge and/or top edge, i.e. away from the middle of the collision member so that the gap between the collision member and the inside wall of the crusher is free, i.e. stays free.

The invention provides the option that two or more collision members, i.e. rings, are placed on top of one another, one of the rings being oriented transversely to the ejection stream. The rings can be replaced when one of the rings has worn out. This has the advantage that deflecting grains that impinge higher or lower are effectively collected by the adjacent rings, whilst the crusher wall is protected. The rings can be placed on top of one another in such a way that the collision surface reliefs are aligned one another, but can also be staggered so that the collision surface reliefs are interspersed. The collision parts can be provided with projections and openings for projections along the top (and bottom), so that the collision parts can be firmly stacked (with a bond). The invention also provides the option that the blocks are stacked with a stagger in the vertical direction such that a horizontal seam that runs parallel to the plane of rotation is not produced.

The invention provides the option that a surface (plate) on which material is able to deposit protrudes along the bottom in front of the collision member, which material lies against some of the collision surfaces like a sloping wall so that some of the material impinges on own material and some impinges on the collision surfaces, i.e. semi-autogenously. The autogenous plate can extend all round but also in one or more segments, by means of which the comminution intensity of the crushing process can be substantially controlled.

The invention provides the option that the collision parts are provided with a strengthening member in the form of, for example, a steel plate that is firmly joined along one side to at least one of the sides of the collision member (not the collision side) or to one of the sides of the individual collision parts (not the collision side). The collision part then consists of a collision block that is provided with a strengthening plate along one of the sides. The strengthening plate is made of a material that has an appreciably higher tensile strength than the material from which the collision block is made. What is achieved by this means is that the collision block (collision part), which is usually brittle because of the high hardness, is held firmly together by the strengthening member and does not fracture (crack) when the collision part starts to wear through or if the granular material contains (harder) foreign constituents of a different type, for example in the form of metal particles, which can impinge with high force and can cause fracture of the collision parts. The high tensile strength of the strengthening member also offers the option of providing this with extremely efficient connector members (for connecting the collision parts to one another), fixing members (for fixing the collision parts to the support member or the crusher housing) and ridge members (for keeping the collision parts some distance away from the inside wall of the crusher housing).

A strengthening member can be very important for the method according to the invention because the back of the collision member (collision parts) is not (completely) supported as is the case with the known collision members. As a result the collision parts can fracture if they are subjected to too severe stress by (coarse and hard) colliding (impinging) material, and when the collision parts start to wear, especially when holes form in the back wall. The strengthening element prevents, (or at least reduces the risk of) the collision parts then starting to crack, as a result of which pieces can break off. The firm bond between the strengthening member and the collision block along the attachment surface can be achieved with the aid of heat. The collision block can be applied in the fluid state to (onto) the strengthening member, but can also be applied in another way, for example in the form of a spray. In this context it is preferable to heat the strengthening member in advance to a temperature approximately equal to that of the material of the collision block that is to be affixed (cast on) and to treat the strengthening member beforehand along the attachment side with a special agent that promotes adhesion.

The adhesion between the attachment side (of the collision block) and the attachment surface (of the accelerator block) can be achieved with the aid of heat treatment, the invention providing, inter alia, the following production methods: According to a first production method the strengthening member and the collision block are cast immediately one after the other and specifically the strengthening member is cast using a first melt and the collision block is cast immediately thereafter, using a second melt, onto the attachment side at the point in time when the first melt is still in the fluid state, or at least the attachment side is at a temperature such that complete fusion of the first and second melt takes place along the attachment surface/side, wherein the alloys of the first and second melt are not identical, wherein the composition of the alloys is so chosen that when the collision element is subjected to thermal after-treatment the collision block develops the desired hardness and the strengthening member retains the desired tensile strength, wherein the attachment side describes an essentially straight surface, wherein, during the production of the accelerator member, the attachment side describes an essentially horizontal surface, wherein, after the strengthening member has been cast, the attachment side is first provided with a film of an agent that prevents oxidation occurring along the attachment side or at least prevents this as far as possible.

It is also possible to cast the strengthening member and the collision block part simultaneously during the production of the collision element, using a melt of the same composition, and to subject only the collision block to a thermal after-treatment, such that the collision block acquires a greater hardness, and thus lower tensile strength, than the strengthening member.

According to another production method, the collision block is cast onto a strengthening member in the form of a piece of plate material. With this method, it is preferable, before the collision block is cast, to bring the metal plate to a temperature that is approximately equal to the temperature of the melt, an additional layer of melt material also being applied to the back of the metal plate, that is the side opposite the attachment side, during the production of the collision element, so that the metal plate assumes virtually the same temperature as the melt, which additional layer is then removed, for which purpose the back is provided with a film of an agent that prevents adhesion between the back and the melt cast on. The adhesion along the attachment side can also be achieved with the aid of sintering and with the aid of soldering.

The invention provides the option that the collision member is partially composed, at least along the collision surfaces, of hard metal or ceramic material, which can have been cast in as separate sections or are subsequently fixed in openings, for example by gluing. Here hard metal is understood to be an alloy of at least one hard, wear-resistant constituent in the form of tungsten carbide or titanium carbide and at least one soft metal constituent in the form of cobalt, iron or nickel.

Here ceramic material is understood to be a material that at least partially consists of aluminium oxide (corundum - AI₂O3) and or at least partially consists of silicon oxide (SiOz), but here can also be understood to be materials such as carbides and silica sand.

The advantage of the collision member (collision element) with collision surface relief according to the invention is thus that the collision member can be arranged a shorter free radial distance away from the rotor than in the case of a stator ring, whilst a good probability of breakage can nevertheless be achieved which, because disturbing influences are avoided, is virtually constant as wear progresses, whilst a maximum quantity of the wear material is consumed and the collision member can consist of one piece, that is a (stator) ring with protruding relief (points), which is much easier to install, is self-supporting and makes it possible to use even more wear material effectively; the collision member can also consist of several collision parts, which is less expensive to produce (cast). BRTEF DESCRIPTION OF THE DRAWINGS

For better understanding, the aims, characteristics and advantages of the method and the device of the invention which have been discussed, and other aims, characteristics and advantages of the method and the device of the invention, are explained in the following detailed description of the method and the device of the invention in relation to accompanying diagrammatic drawings.

Figure 1 explains, diagrammatically, the method according to the invention. Figure 2 explains, diagrammatically, the method according to the invention. Figure 3 describes, diagrammatically, the movement of the material along a straight stream.

Figure 4 shows how the base angle is determined by, on the one hand, the free radial distance from the axis of rotation and by the take-off angle.

Figure 5 gives the relationship between the take-off radius and the requisite base radius for a base angle of 60°. Figure 6 gives the relationship between the take-off radius and the requisite base radius for a base angle of 70°.

Figure 7 gives the relationship between the take-off radius and the requisite base radius for a base angle of 80°.

Figure 8 shows, diagrammatically, a rotor and a collision member. Figure 9 shows, diagrammatically, a cross-section B-B according to Figure 10 of a first device according to the method of the invention.

Figure 10 shows, diagrammatically, a longitudinal section A-A according to Figure 9 of a first device according to the method of the invention.

Figure 11 shows, diagrammatically, a cross-section D-D according to Figure 12 of a second device according to the method of the invention.

Figure 12 shows, diagrammatically, a longitudinal section C-C according to Figure 11 of a second device according to the method of the invention.

Figure 13 shows, diagrammatically, a cross-section F-F according to Figure 14 of a third device according to the method of the invention. Figure 14 shows, diagrammatically, a longitudinal section E-E according to Figure 13 of a third device according to the method of the invention.

Figure 15 shows, diagrammatically, a cross-section H-H according to Figure 16 of a fourth device according to the method of the invention.

Figure 16 shows, diagrammatically, a longitudinal section G-G according to Figure 15 of a fourth device according to the method of the invention.

Figure 17 shows, diagrammatically, a cross-section J-J according to Figure 18 of a fifth device according to the method of the invention.

Figure 18 shows, diagrammatically, a longitudinal section I-I according to Figure 17 of a fifth device according to the method of the invention.

Figure 19 shows, diagrammatically, a cross-section L-L according to Figure 20 of a sixth device according to the method of the invention.

Figure 20 shows, diagrammatically, a longitudinal section K-K according to Figure 19 of a sixth device according to the method of the invention.

Figure 21 shows, diagrammatically, a cross-section N-N according to Figure 22 of a seventh device according to the method of the invention. Figure 22 shows, diagrammatically, a longitudinal section M-M according to Figure 21 of a seventh device according to the method of the invention.

Figure 23 shows, diagrammatically, a collision member.

Figure 24 shows, diagrammatically, the wearing through of a collision member.

Figure 25 shows, diagrammatically, a collision member that has worn through. Figure 26 shows, diagrammatically, a side view P-P according to Figure 27 of a collision member that is provided with a strengthening member that is provided with a fixing member.

Figure 27 shows, diagrammatically, a plan view O-O according to Figure 27.

Figure 28 shows, diagrammatically, a side view of a collision member that is provided with a strengthening member that is provided with a fixing member that is fixed to a support member. Figure 29 shows, diagrammatically, a front view R-R of a symmetrical collision part that is provided along the back with a strengthening member and is constructed with two trapezium- shaped impact surfaces, according to Figure 30.

Figure 30 shows, diagrammatically, a side view Q-Q according to Figure 29.

Figure 31 shows, diagrammatically, a plan view S-S according to Figure 30. Figure 32 shows, diagrammatically, a cross-section U-U according to Figure 33 of a symmetrical collision part that is provided along the back with a strengthening member.

Figure 33 shows, diagrammatically, a longitudinal section T-T according to Figure 32.

Figure 34 shows, diagrammatically, a cross-section W-W according to Figure 35 of a cylindrical collision part. Figure 33 shows, diagrammatically, a longitudinal section V-V according to Figure 34.

Figure 36 shows, diagrammatically, two collision parts that are connected to one another with the aid of a connector member in the form of a hook connector.

Figure 37 shows, diagrammatically, a collision member that is arranged in a bed of own material.

The drawings are not structural drawings but indicate diagrammatically - in sketch form - a number of possible embodiments and characteristics that are important or of essential importance for the description, the characterisation and the use of the rotor according to the invention. In the case of sections, shading is not always indicated and only the most important details are indicated by broken lines. Moreover, in sections frequently only the components which are located on or close to the sections, i.e. of a section, are indicated and no items and members located further towards the rear.

BEST WAY OF IMPLEMENTING THE METHOD AND DEVICE OF THE INVENTION

A detailed reference to the preferred embodiments of the invention is given below. Examples thereof are shown in the appended drawings. Although the invention will be described together with the preferred embodiments, it must be clear that the embodiments described are not intended to restrict the invention to those specific embodiments. On the contrary, the intention of the invention is to comprise alternatives, modifications and equivalents which fit within the nature and scope of the invention as defined by appended claims.

Figures 1 and 2 explain, diagrammatically, the method according to the invention for causing granular material to collide at least once with the aid of at least one collision member with the aim of comminuting the material, comprising: - feeding the material onto a rotor (1) that can be rotated (2) about an axis of rotation (3) in at least one direction, which feeding takes place with the aid of a feed member (not indicated here) at a feed location (4) close to the axis of rotation (3), which fed material moves outwards from the feed location (4) in the direction of the outer edge (5) of the rotor (1) under the influence of the rotary movement of the rotor (1); - accelerating the fed material in at least one step with the aid of an accelerator unit (6), which accelerator unit (6) is carried by the rotor (1) and consists of at least one accelerator member (here consisting of a guide member) that is provided with at least one acceleration surface (7) (a guide surface here) that extends in the direction of the outer edge (5) of the rotor (1), which accelerated material leaves the accelerator unit (6) at a take-off location (8) and is thrown outwards from the rotor (1) and then moves outwards along a straight ejection stream (9) at a takeoff angle (α) between the straight line (10) having thereon the take-off location (8) that is oriented peφendicularly to the radial line (11) from the axis of rotation (3) having thereon the take-off location (8) and the straight line (12), from the take-off location (8), that is determined by the movement of the material along the straight ejection stream (9), the material thrown outwards moving along the ejection stream (9) (or line (12)) in an increasingly radial direction as the material moves further away from the axis of rotation (3), viewed from a stationary standpoint and viewed from the axis of rotation (3), which take-off location (8) is located a first radial distance (rl) away from the axis of rotation (3);

- causing the ejected material to collide with the aid of a stationary collision member (13)(14) that is located a greater radial distance away from the axis of rotation (3) than is the outer edge (5) of the rotor (1) and extends in an essentially regular manner around the axis of rotation (3), at least between two radial planes from said axis of rotation (3), which collision member (13)(14) consists of at least one collision part (Figure 1 shows, diagrammatically, a collision member (13) that consists of one piece, i.e. a collision part, and Figure 2 shows, diagrammatically, a collision member (14) that consists of a number of collision parts (15)) that extends between an inscribed circle (16) having a radius (r2), the centre of which is coincident with the axis of rotation (3), that touches the sides (17)(18) of the collision member (13)(14) on the inside, where r2 > rl, and a circumscribed circle (19) having a radius (r4), the centre of which is essentially coincident with the axis of rotation (3), that touches the sides (20)(21) of the collision member (13)(14) on the outside, where r4 > r2, with, between the inscribed circle (16) and the circumscribed circle (19), an essentially imaginary base circle (22) having a radius (r3), the centre of which is essentially coincident with the axis of rotation (3), that essentially divides the collision member (13)(14) (and the individual collision parts (15)) into a ring segment (23) and a relief segment (24), where r2 < r3 < r4, which ring segment (23) extends essentially completely around the axis of rotation (3) between the base circle (22) and the circumscribed circle (19), which relief segment (24) is provided with at least one collision surface relief (25)(26) which protrudes in the direction of the axis of rotation (3) and is provided with at least one collision surface (27)(28) that essentially extends between the base circle (22) and the inscribed circle (16) and is essentially oriented transversely to the ejection stream (9), the straight line (12) having thereon the ejection stream (9) intersecting the base circle (22) at a base angle (β') between the straight line (12) having thereon the ejection stream (9) and the straight line (29), having thereon the location (30) where the straight line (12) having thereon the ejection stream (9) intersects the base circle (22), that is oriented peφendicularly to the straight line (31) from the axis of rotation (3) having thereon the location (30) where the straight line (12) having thereon the ejection stream (9) intersects the base circle (22); - characterised in that

- the third radial distance (r3) from the axis of rotation (3) to the base circle (22) in relation to the first radial distance (rl) from the axis of rotation (3) to the take-off location (8) - i.e. the ratio r3/rl - is chosen at least so large that the line (12) that is coincident with the ejection stream (9) intersects the base circle (22) at a base angle (β^τ) that is equal to or greater than 60°, viewed from a stationary standpoint and where the ratio r3/rl is at least equal to or greater than 1.70.

Figures 3 to 8 explain, diagrammatically, the method in more detail. As is indicated diagrammatically in Figure 3, the take-off angle (α) essentially determines the first angle of movement (α¹ = 90° - α) and this angle of movement changes when the material moves along the straight stream (32), the angle being referred to as apparent angle of movement (α"). As the material moves further away from the axis of rotation (33) along the straight stream (32) the apparent angle of movement (α") becomes ever smaller. The take-off angle (α) and the shift in the apparent angle of movement (α") can be calculated reasonably accurately and simulated with the aid of a computer (see US 5 860 605 that was drawn up in the name of the Applicant) or established with the aid of high speed video recordings.

The reason for the shift in the apparent angle of movement (α") is that the grain leaves the rotor (35) from the take-off location (34) a first distance (rl) away from said axis of rotation (33), as a result of which the polar coordinates of the axis of rotation (33) are not coincident with the polar coordinates of the take-off location (34). As a result an - apparent - shift of the velocity components takes place along the straight ejection stream (32) that the grain describes. When the material moves further away from the axis of rotation (33) the absolute velocity (Vabs) remains the same but the radial velocity component (Vr) increases, whilst the transverse velocity component (Vt) decreases (see PCT/NLO 1/00482 that was drawn up in the name of the Applicant). The consequence of this is that, as it moves further away from the axis of rotation (33), the material starts to move - in the apparent sense - in an increasingly radial direction, viewed from said axis of rotation (33). Figure 4 shows, diagrammatically, how the base angle (β') is determined by, on the one hand, the free radial distance (r3) from the axis of rotation (36) and by the take-off angle (α); the base angle (β¹) can thus be calculated with the aid of the ratio (r3/rl) that essentially must comply with the equation:

r, cosα — > r_x cosβ'

rl = the first radial distance from the axis of rotation (36) to the take-off location (37). r3 = the second radial distance from the axis of rotation (36) to the base circle (38). α = the take-off angle (in degrees) between the straight line (39) having thereon the take-off location (37) that is oriented peφendicularly to the radial line (40) from the axis of rotation (36) having thereon the take-off location (37) and the straight line (41), from the take-off location (37), that is determined by the movement of the material along the straight ejection stream (42). β' = the base angle (in degrees) between the straight line (41) having thereon the ejection stream (42) and the straight line (43), having thereon the location (44) where the straight line (41) having thereon the ejection stream (42) intersects the base circle (38), that is oriented peφendicularly to the straight line (45) from the axis of rotation (36) having thereon the location (44) where the straight line (41) having thereon the ejection stream (42) intersects the base circle

(38).

The relationship between the take-off radius (rl) and the requisite base radius (r3) to achieve respective base angles (β') of 60°, 70° and 80° with take-off angles (_α) of 10°, 20°, 30°, 40°, 50° and 60° is shown in Figures 5, 6 and 7. To obtain a base angle (β¹) greater than 60°, and preferably of 65° - 75°, the radial distance between the rotor (rl) and the base circle (r3) must be chosen fairly large, but can be restricted if the take-off angle (α) increases.

In particular in the case of the known single impact crusher, where the material is propelled outwards from the accelerator member in the direction of the stationary collision member and the take-off angle (α) is usually no greater than 35° - 40°, the radial free distance must be chosen fairly large. To obtain a base angle (β') of 70° the ratio (r3/rl) must be set at « 2.4 for a take-off angle

(α) of 37.5° (Figure 6), at » 4.5 for a base angle (β') of 80° (Figure 6) and at « 1.5 for a base angle (β') of 60° (Figure 5).

Figure 8 shows, diagrammatically, a rotor (46) and a collision member (47) where the material is brought into a straight ejection stream (49) from a take-off location (48) at a take-off angle ( ), the straight line (50) that is coincident with the ejection stream (49) intersecting the base circle (51) at a base angle (β'). As is indicated diagrammatically, a shift (decrease) in the apparent angle of movement (α'") takes place along the straight ejection stream (49) which makes it possible to arrange the collision member (47) centrally around the rotor (46) at such a distance away from the axis of rotation (52) that the base angle (β') is essentially predetermined, which makes it possible first to allow the material to impinge at a specific collision angle (β) on the collision surface (53) of the collision surface relief (54) and then, when the collision surface relief (54) has worn away, to allow it to impinge on the base collision surface (55) that essentially is coincident with the base circle (51) at said base angle (β¹). Figures 9 to 22 show, diagrammatically a number of (seven) devices which are possible according to the method of the invention, but the invention is not restricted to these devices.

Figures 9 and 10 show, diagrammatically, a first device (56) according to the method of the invention for causing granular material to collide at least once with the aid of at least one stationary collision member (57), comprising: - a crusher housing (58) that is provided with a crusher chamber (59) in which crushing essentially takes place;

- a rotor (60) that is arranged in the crusher chamber (59) which rotor (60) can be rotated in at least one direction (two (61) here) about an axis of rotation (62) and is supported by a shaft (63);

- a feed member (64) for feeding the material onto the rotor (60) at a feed location (65) close to the axis of rotation (62);

- at least one accelerator unit (69) for accelerating the fed material in at least one step, which accelerator unit (69) is carried by the rotor (60) for accelerating the material under the influence of centrifugal force, which accelerated material leaves the accelerator unit at a take-off location (67) and is thrown outwards from the rotor (60) at a take-off angle (α) along a straight ejection stream (68) and then moves further outwards along the straight ejection stream (68), which take-off location (67) is located a first radial distance (rl) away from the axis of rotation (62);

- here the accelerator unit (69) is provided with at least one (four here) first accelerator member (70) and a second accelerator member (71) that is associated with the first accelerator member (70) for accelerating the material in two phases, which first accelerator member (70) is provided with at least a first acceleration surface (72) for accelerating the fed material in a first phase with the aid of guiding along the first acceleration surface (72), in such a way that the guided material is brought into a spiral path (73) directed backwards, viewed from a standpoint moving with the first accelerator member (70), which second accelerator member (71) is provided with at least a second acceleration surface (74) (here the second accelerator member (71) is of symmetrical construction and provided with two acceleration surfaces), that is oriented essentially transversely to the spiral path (73), for accelerating the guided material in a second phase by striking the second acceleration surface (74), the various aspects being such that the first acceleration phase takes place a shorter radial distance away from the rotor (60) than the second acceleration phase, which occurs an appreciably greater radial distance away;

- at least one stationary collision member (57) that is supported by the crusher housing (58) with the aid of a support member (75) and is located a greater radial distance away from the axis of rotation (62) than is the outer edge (66) of the rotor (60) and extends in an essentially regular manner around the axis of rotation (62), at least between two radial planes from said axis of rotation (3), which collision member (57) consists of at least one collision part (a number of collision parts (76) here) that extends between an inscribed circle (77) having a radius (r2), the centre of which is essentially coincident with the axis of rotation (62), that touches the sides (78) of the collision member (57) on the inside, where r2 > rl, and a circumscribed circle (79) having a radius (r4), the centre of which is essentially coincident with the axis of rotation (62), that touches the sides (80) of the collision member (57) on the outside, where r4 > r2, with, between the inscribed circle (77) and the circumscribed circle (79), an essentially imaginary base circle (81) having a radius (r3), the centre of which is essentially coincident with the axis of rotation (62), that essentially divides the collision member (57) (and each collision part (76)) into a ring segment (82) and a relief segment (83), where r2 < r3 < r4, which ring segment (82) extends essentially completely around the axis of rotation (62) between the base circle (81) and the circumscribed circle (79), which relief segment (83) is provided with at least one collision surface relief (84) which protrudes in the direction of the axis of rotation (62) (here each collision part (76) is provided with a symmetrical collision surface relief (84)) and is provided with at least one collision surface (two collision surfaces (85) here) that extends between the base circle (81) and the inscribed circle (77) and is oriented essentially transversely to the ejection stream (68);

- characterised in that:

- the third radial distance (r3) from the axis of rotation (62) to the base circle (81) in relation to the first radial distance (rl) from the axis of rotation (62) to the take-off location (67) - i.e. the ratio r3/rl - is chosen at least so large that the line (86) that is coincident with the ejection stream (68) intersects the base circle (81) at a base angle (β') that is equal to or greater than 60° (« 65° here), viewed from a stationary standpoint, the ratio r3/rl being at least equal to or greater than 1.70 (« 2.00 here). Here the support member (75) consists of an annular plate that extends from the inside (87) of the crusher housing (58) in the direction of the axis of rotation (62) on which support member (75) the collision member (57) is arranged. Here the collision member (57) is located partially some distance away from the inside wall (87) of the crusher housing (58) such that at least part of the side (80) of the collision member (57) that faces the inside wall (87) of the crusher housing (58) is not in contact with the inside wall (87), such that there is an open space (88) all round between the collision member (57) and the inside wall (87) of the crusher housing (58), which open space (88) can fill with own material when the collision member (57) wears through, such that the own material protects the inside wall (87) of the crusher housing (58) against wear when said collision member (57) wears through (see Figures 23 to 25). The space (88) between the collision member (57) and the inside wall (87) extends all round from the plane (89) that is essentially coincident with the plane along which the ejection stream (68) moves in the direction of the edges (90)(91) of the collision member (57) along at least part of the side (80) of the collision member (57) that faces the inside wall (87). To this end the inside wall (87) of the crusher housing (58) is provided here with a spacer member (two spacer members (92)(93) here) in the form of a spacer rim that is located between the top edge (90) of the collision member (57) and the inside wall (87) and the bottom edge (91) of the collision member (57) and the inside wall (87) such that the side (80) of the collision member (57) that faces the inside wall (87) of the crusher housing (58) is at least partially some distance away from the inside wall (87).

Here the rotor (60) can be rotated in both directions (61), forwards and backwards, and the collision surface relief (84) is provided with two collision surfaces (85) for each of the directions of rotation (61). Here the collision surface relief (84) is of mirror symmetrical construction with respect to a radial plane (94) from the axis of rotation (62) that intersects the collision surface relief (84) in the middle between the two collision surfaces (85).

The invention provides the option that the collision surface (85) is not of straight construction but, for example, has the shape of the evolvent of the ejection stream (68); the collision surface (85) can also be oriented obliquely downwards. Figures 11 and 12 shows a second device (95) according to the method of the invention that is essentially identical to the first device (56) from Figures 9 and 10, where the collision member (96) consists of a (collision) part and is provided with a number of symmetrical point-shaped (triangular) collision surface reliefs (97) that are of symmetrical construction and are each provided with two identical collision surfaces (98). Here the collision member (96) is supported by a support member (99) that consists of an annular plate that extends from the inside (100) of the crusher housing (101) in the direction of the axis of rotation (102), on which support member (99) the collision member (96) is arranged.

Figures 13 and 14 show a third device (103) according to the method of the invention that is essentially identical to the first device (56) from Figures 9 and 10, where the collision member (104) consists of a number of collision parts (105), each of which is provided with two identical symmetrical collision surface reliefs (106)(107) each of which is provided with two identical collision surfaces (108). The collision member (104) is supported by a support member (109) that consists of a holder (here an upright edge (110) and a baseplate (111)) for the collision member (104), which support member (109) can be removed together with the collision member (104) and which support member (109) (holder) bears on a support member (112) in the form of an annular rim.

Figures 15 and 16 show a fourth device (113) according to the method of the invention that is essentially identical to the first device (56) from Figures 9 and 10, where the crusher housing (114) is provided with three essentially identical collision members (115)(116)(117), each of which consists of a (collision) part and each of which is provided with a number of symmetrical collision surface reliefs (118), which collision members (115)(116)(117) extend in parallel next to one another (stacked on top of one another) around the axis of rotation (119), the collision surfaces (120) of the middle collision member (116) being oriented essentially transversely to the ejection stream (121), such that the collision members (115)(116)(117) can be replaced when one collision member (116) has worn out as a result of wear. Here the collision members (115)(116)(117) are so stacked that the collision surface reliefs (118)(122) are staggered, but the collision members (115)(116)(117) can, of course, also be stacked precisely directly above one another (or with an arbitrary relationship). The invention provides the option of a stacked construction of collision members which consist of several collision parts that are stacked in a straight relationship or arbitrary relationship.

Such a stacked construction has the advantage that grains that deflect downwards or upwards to some extent are effectively collected by the adjacent collision members (115)(117); furthermore, the inside wall (123) of the crusher chamber (124) is effectively protected. Figures 17 and 18 show a fifth device (125) according to the method of the invention that is essentially identical to the first device (56) from Figures 9 and 10, where the collision member (126) is made up of a number of symmetrical collision parts (127), each of which is provided along the side (128) that faces the inside wall (129) of the crusher housing (130) along the top edge (131) with two spacer members (132) in the form of spacer ridges protruding in the direction of the outer edge (129) which hold the collision part (127) some distance away from the inside wall (129). Here the collision parts (127) are each provided along the back (the side (128) that faces the inside wall of the crusher housing (140)) with a strengthening member (135) in the form of a metal strengthening plate that is made of a structural material having a greater tensile strength than the structural material from which the collision part (127) (block) is made. The strengthening member (135) and the collision member (127) (block) are firmly joined to one another along the attachment side (back (128)). The collision part (127) with strengthening member is discussed further in Figures 26 to 36. The spacer members (132) form part of the strengthening member (135). Here the collision member (126) is supported by a support member (133) that consists of an annular plate that extends from the inside wall (129) of the crusher housing (130) in the direction of the axis of rotation (134), on which support member (133) the collision member (126) is arranged. The space (137) between the collision member (126) and the inside wall (129) of the crusher housing (130) is essentially completely open all round (is interrupted only by the spacer members (132)), such that granular material is able to deposit in this space (137) when the collision member (126) wears through (see Figures 23 to 25), such that the granular material protects the inside wall (129) of the crusher housing (130) against colliding material. Figures 19 and 20 show a sixth device (138) according to the method of the invention that is essentially identical to the first device (56) from Figures 9 and 10, where the collision member (139) consists of a number of collision parts (140) that are provided with a symmetrical collision surface relief (141) that here is of (semi-)circular construction.

Figures 21 and 22 show a seventh device (142) according to the method of the invention that is essentially identical to the first device (56) from Figures 9 and 10, where the collision member (143) is made up of cylindrical collision parts (144), the cylinder axis (145) of which is essentially parallel to the axis of rotation (146) of the rotor (147).

Figures 23, 24 and 25 show, diagrammatically, the wearing through of a collision member (148a)(148b)(148c) that has been arranged some distance (149) away from the inside wall (150) of the crusher housing (151). Here the collision member (148a) is supported by a support member (152) that consists of an annular plate that extends from the inside wall (150) of the crusher housing (151) in the direction of the axis of rotation (not indicated here). When the collision member (148a) wears completely through (148c), the space (153) (between the collision member (148c) and the inside wall (150) of the crusher housing (151)) fills with own material (154) that as an autogenous bed autogenously protects the inside wall (150) against impinging material.

Figures 26, 27 and 28 show, diagrammatically, a collision member (155) that is provided with a strengthening member (156) that is provided with a fixing member (157) (in the form of two hooks) for fixing said collision member (155) (collision part (159)) to the support member (158). The collision part (159) consists of a collision block (160) that is provided with a strengthening member (156) that extends along at least part of one of the sides (here the back (161)) of the collision block (160) that does not face the axis of rotation (not indicated here) and is firmly joined to the collision block (160), which strengthening member (156) is made of a structural material that has an appreciably greater tensile strength than the structural material from which the collision block (160) is made. The high tensile strength makes it possible to construct the fixing member (157) very simply (limited size/volume) and effectively, here in the form of two hooks by means of which the collision parts (159) are mounted on the support member (158), and the collision parts (159) are supported by an annular plate (162) (support member). The annular plate (162) is provided with a number of spacer ridges (163) which prevent the collision parts being able to shift. The open space (164) between the collision member (155) and the crusher wall (165) can fill with an autogenous bed, as is indicated in Figures 23 to 25. Figures 29, 30 and 31 show, diagrammatically, a symmetrical collision part (166) that is provided along the back (171) with a strengthening member (167) and is constructed with two trapezium-shaped impact surfaces (168), which makes it possible to save wear material.

Figures 32 and 33 show, diagrammatically, a symmetrical collision member (169) that is provided along the back (170) with a strengthening member (172), which strengthening member (172) is provided along the bottom (173) with a protruding edge (174) that drops into a groove (175) in the support member (176) that here consists of an annular plate that extends from the inside wall (177) of the crusher housing (178) in the direction of the axis of rotation (not indicated here). Behind each of the collision parts (169) there is also a spacer member (179) fixed to the inside wall (177) of the crusher housing (178) in the form of a protruding projection. Figures 34 and 35 show, diagrammatically, a cylindrical collision part (180), the cylinder axis (181) of which is essentially parallel to the axis of rotation (not indicated here), which collision part (180) is provided along the bottom (182) with a strengthening member (183) that is provided with a protruding projection (184) (round here, but can also be made square or some other shape) that drops into an opening (185) in the support member (186) that here consists of an annular plate that extends from the inside wall (187) of the crusher housing (188) in the direction of the axis of rotation (not indicated here). Behind each of the collision parts (180) there is also a spacer member (189) fixed to the inside wall (187) of the crusher housing (188) in the form of a protruding projection.

Figure 36 shows, diagrammatically, two collision parts (190)(191) that are joined to one another with the aid of a connector member (192) in the form of a hook connector by means of which the blocks (190)(191) are connected to one another such that they form a "fixed" ring that is not able to shift backwards (outwards).

Figure 37 shows, diagrammatically, a collision member (193) that is arranged in a bed (194) of own material that extends between the collision member (193) and the inside wall (195) of the crusher housing (196) (that is along the back) and along the bottom (197) and along the top (198) of the collision member (193). The collision member (193) bears on projections (not indicated here) that essentially are also in said bed (194) of own material.

The above descriptions of specific embodiments of the present invention have been given with a view to illustrative and descriptive puφoses. They are not intended to be an exhaustive list or to restrict the invention to the precise forms given, and having due regard for the above explanation, many modifications and variations are, of course, possible. The embodiments have been selected and described in order to describe the principles of the invention and the practical application possibilities thereof in the best possible way in order thus to enable others skilled in the art to make use in an optimum manner of the invention and the diverse embodiments with the various modifications suitable for the specific intended use. The intention is that the scope of the invention is defined by the appended claims according to reading and inteφretation in accordance with generally accepted legal principles, such as the principle of equivalents and the revision of components.

Claims

CLAMS

1. Method for causing granular material to collide at least once with the aid of at least one collision member with the aim of comminuting the material, comprising: - feeding the material onto a rotor (1) that can be rotated (2) about an axis of rotation (3) in at least one direction, which feeding takes place with the aid of a feed member at a feed location (4) close to said axis of rotation (3), which fed material moves outwards from said feed location (4) in the direction of the outer edge (5) of said rotor (1) under the influence of the rotary movement of said rotor (1); - accelerating said fed material in at least one step with the aid of an accelerator unit (6), which accelerator unit (6) is carried by said rotor (1) and consists of at least one accelerator member that is provided with at least one acceleration surface (7) that extends in the direction of said outer edge (5) of said rotor (1), which accelerated material leaves said accelerator unit (6) at a take-off location (8) and is thrown outwards from said rotor (1) and then moves outwards along a straight ejection stream (9) at a take-off angle ( ) that is determined by the movement of said material along said straight ejection stream (9), said material thrown outwards moving along said ejection stream (9) in an increasingly radial direction as the material moves further away from said axis of rotation (3), viewed from a stationary standpoint and viewed from said axis of rotation (3), which take-off location (8) is located a first radial distance (rl) away from said axis of rotation (3); - causing the ejected material to collide with the aid of a stationary collision member (13)(14) that is located a greater radial distance away from said axis of rotation (3) than is said outer edge (5) of said rotor (1) and extends in an essentially regular manner around said axis of rotation (3), at least between two radial planes from said axis of rotation (3), which collision member (13)(14) consists of at least one collision part (15) that extends between an inscribed circle (16) having a radius (r2), the centre of which is coincident with said axis of rotation (3), that touches the sides (17)(18) of said collision member (13)(14) on the inside, where r2 > rl, and a circumscribed circle (19) having a radius (r4), the centre of which is essentially coincident with said axis of rotation (3), that touches the sides (20)(21) of said collision member (13)(14) on the outside, where r4 > r2, with, between said inscribed circle (16) and said circumscribed circle (19), an essentially imaginary base circle (22) having a radius (r3), the centre of which is essentially coincident with said axis of rotation (3), that essentially divides said collision member (13)(14) into a ring segment (23) and a relief segment (24), where r2 < r3 < r4, which ring segment (23) extends essentially completely around the axis of rotation (3) between the base circle (22) and the circumscribed circle (19), which relief segment (24) is provided with at least one collision surface relief (25)(26) which protrudes in the direction of said axis of rotation (3) and is provided with at least one collision surface (27)(28) that essentially extends between said base circle (22) and the inscribed circle (16) and is essentially oriented transversely to the ejection stream (9);

- characterised in that

- the third radial distance (r3) from said axis of rotation (3) to said base circle (22) in relation to said first radial distance (rl) from said axis of rotation (3) to said take-off location (8) - i.e. the ratio r3/rl - is chosen at least so large that the line that is coincident with the ejection stream (9) intersects said base circle (22) at a base angle (β') that is equal to or greater than 60°, viewed from a stationary standpoint, the ratio r3/rl being at least equal to or greater than 1.70.

2. Method according to Claim 1, wherein said base angle is equal to or greater than 65°.

3. Method according to Claim 1, wherein said base angle is equal to or greater than 70°.

4. Method according to Claim 1, wherein said ratio r3/rl is essentially determined by the equation:

r, cosα cosβ'

where: rl = the first radial distance from said axis of rotation to said take-off location. r3 = the second radial distance from said axis of rotation to said base circle, α = the take-off angle (in degrees) between the straight line having thereon said take-off location that is oriented peφendicularly to the radial line from said axis of rotation having thereon said take-off location and the straight line, from said take-off location, that is determined by the movement of said material along said straight ejection stream. β' = the base angle (in degrees) between the straight line having thereon said ejection stream and the straight line, having thereon the location where the straight line having thereon said ejection stream intersects said base circle, that is oriented peφendicularly to the straight line from said axis of rotation having thereon the location where the straight line having thereon said ejection stream intersects said base circle.

5. Method according to Claim 1, wherein said ratio r3/rl is at least equal to or greater than 1.75.

6. Method according to Claim 1, wherein said ratio r3/rl is at least equal to or greater than 1.80.

7. Method according to Claim 1, wherein said ratio r3/rl is at least equal to or greater than 1.85.

8. Method according to Claim 1, wherein said ratio r3/rl is at least equal to or greater than 1.90.

9. Method according to Claim 1, wherein said ratio r3/rl is at least equal to or greater than

1.95.

10. Method according to Claim 1, wherein said ratio r3/rl is at least equal to or greater than 2.0.

11. Method according to Claim 1, wherein said ratio r3/rl is at least equal to or greater than 2.25.

12. Method according to Claim 1, wherein said ratio r3/rl is at least equal to or greater than

2.50.

13. Method according to Claiml, wherein the radial distance between said base circle and said inscribed circle, i.e. (r3 - r2), is equal to or less than the radial distance between said base circle and said circumscribed circle, i.e. (r4 - r3).

14. Method according to Claim 13, the ratio (r4 - r3)/(r3 - r2) is equal to or greater than 1.1.

15. Method according to Claim 13, wherein the ratio (r4 - r3)/(r3 - r2) is at least equal to or greater than 1.15.

16. Method according to Claim 13, wherein the ratio (r4 - r3)/(r3 - r2) is at least equal to or greater than 1.20.

17. Method according to Claim 13, wherein the ratio (r4 - r3)/(r3 - r2) is at least equal to or greater than 1.25.

18. Method according to Claim 1, wherein said accelerator unit is provided with at least a first accelerator member and a second accelerator member that is associated with said first accelerator member for accelerating said material in two phases, which first accelerator member is provided with at least a first acceleration surface for accelerating said fed material in a first phase with the aid of guiding along said first acceleration surface, in such a way that said guided material is brought into a spiral path oriented backwards, viewed from a standpoint moving with said first accelerator member, which second accelerator member is provided with at least a second acceleration surface, that is oriented essentially transversely to said spiral path, for accelerating said guided material in a second phase by striking said second acceleration surface, the various aspects being such that said first acceleration phase takes place a shorter radial distance away from said rotor than said second acceleration phase, which occurs an appreciably greater radial distance away.

19. Method according to Claiml, wherein said accelerator unit is provided with at least one guide member for accelerating said material in one phase, which guide member is provided with at least one guide surface that at least partially extends in the direction of said outer edge of said rotor.

20. Method according to Claim 1, wherein said axis of rotation is not oriented vertically.

21. Method according to Claim 1, wherein said collision element consists of a collision block that is provided with a strengthening member that extends along at least part of one of the sides of said collision block that does not face said axis of rotation and is firmly joined to said collision block, which strengthening member is made of a material that has an appreciably greater tensile strength than said material from which said collision block is made.

22. Comminution device for carrying out the method according to one of Claims 1 to 21, for causing granular material to collide at least once with the aid of at least one collision member (57), comprising:

- a crusher housing (58) that is provided with a crusher chamber (59);

- a rotor (60) that is arranged in said crusher chamber (59) which rotor (60) can be rotated in at least one direction about an axis of rotation (62) and is supported by a shaft (63);

- a feed member (64) for feeding said material onto said rotor (60) at a feed location (65) close to said axis of rotation (62);

- at least one accelerator unit (69) for accelerating said fed material in at least one step, which accelerator unit (69) is carried by said rotor (60) and consists of at least one accelerator member that is provided with at least one acceleration surface that extends in the direction of the outer edge (66) of said rotor (60) for accelerating the material under the influence of centrifugal force, which accelerated material leaves said accelerator unit (69) at a take-off location (67) and is thrown outwards from said rotor (60) along a straight ejection stream (68) and then moves outwards along a straight ejection stream (68) at a take-off angle (α) that is determined by the movement of said material along said straight ejection stream (68), which take-off location (67) is located a first radial distance (rl) away from said axis of rotation (62); - at least one stationary collision member (57) that is supported by said crusher housing (58) with the aid of a support member (75) and is located a greater radial distance away from said axis of rotation (62) than is said outer edge (66) of said rotor (60) and extends in an essentially regular manner around said axis of rotation (62), at least between two radial planes from said axis of rotation (62), which collision member (57) consists of at least one collision part (76) that extends between an inscribed circle (77) having a radius (r2), the centre of which is essentially coincident with said axis of rotation (62), that touches the sides (78) of said collision member (57) on the inside, where r2 > rl, and a circumscribed circle (79) having a radius (r4), the centre of which is essentially coincident with said axis of rotation (62), that touches the sides (80) of said collision member (57) on the outside, where r4 > r2, with, between said inscribed circle (77) and said circumscribed circle (79), an essentially imaginary base circle (81) having a radius (r3), the centre of which is essentially coincident with said axis of rotation (62), that essentially divides said collision member (57) into a ring segment (82) and a relief segment (83), where r2 < r3 < r4, which ring segment (82) extends essentially completely around said axis of rotation (62) between said base circle (81) and said circumscribed circle (79), which relief segment (83) is provided with at least one collision surface relief (84) which protrudes in the direction of said axis of rotation (62) and is provided with at least one collision surface (85) that extends between said base circle (81) and said inscribed circle (77) and is oriented essentially transversely to said ejection stream (68);

- characterised in that:

- said third radial distance (r3) from said axis of rotation (62) to the base circle (81) in relation to said first radial distance (rl) from said axis of rotation (62) to said take-off location (67) - i.e. the ratio r3/rl - is chosen at least so large that the line (86) that is coincident with said ejection stream (68) intersects said base circle (81) at a base angle (β') that is equal to or greater than 60°, viewed from a stationary standpoint, the ratio r3/rl being at least equal to or greater than 1.70.

23. Comminution device according to Claim 22, wherein said base angle is equal to or greater than 65°.

24. Comminution device according to Claim 22, wherein said base angle is equal to or greater than 70°.

25. Comminution device according to Claim 22, where: said ratio r3/rl is essentially determined by the equation:

r₃ cosα cosβ'

where: rl = the first radial distance from said axis of rotation to said take-off location. r3 = the second radial distance from said axis of rotation to said base circle. = the take-off angle (in degrees) between the straight line having thereon said take-off location that is oriented peφendicularly to the radial line from said axis of rotation having thereon said take-off location and the straight line, from said take-off location, that is determined by the movement of the material along said straight ejection stream. β' = the base angle (in degrees) between the straight line having thereon said ejection stream and the straight line, having thereon the location where the straight line having thereon said ejection stream intersects said base circle, that is oriented peφendicularly to the straight line from said axis of rotation having thereon the location where the straight line having thereon said ejection stream intersects said base circle.

26. Comminution device according to Claim 22, wherein the ratio r3/rl is at least equal to or greater than 1.75.

27. Comminution device according to Claim 22, wherein the ratio r3/rl is at least equal to or greater than 1.80.

28. Comminution device according to Claim 22, wherein the ratio r3/rl is at least equal to or greater than 1.85.

29. Comminution device according to Claim 22, wherein the ratio r3/rl is at least equal to or greater than 1.90.

30. Comminution device according to Claim 22, wherein the ratio r3/rl is at least equal to or greater than 1.95.

31. Comminution device according to Claim 22, wherein the ratio r3/rl is at least equal to or greater than 2.0.

32. Comminution device according to Claim 22, wherein the ratio r3/rl is at least equal to or greater than 2.25.

33. Comminution device according to Claim 22, wherein the ratio r3/rl is at least equal to or greater than 2.50.

34. Comminution device according to Claim 22, wherein the radial distance between said base circle and said inscribed, i.e. (r3 - r2), is equal to or less than the radial distance between said base circle and said circumscribed circle, i.e. (r4/r3).

35. Comminution device according to Claim 34, the ratio (r4 - r3)/(r3 - r2) is equal to or greater than 1.1.

36. Comminution device according to Claim 34, wherein the ratio (r4 - r3)/(r3 - r2) is at least equal to or greater than 1.15.

37. Comminution device according to Claim 34, wherein the ratio (r4 - r3)/(r3 - r2) is at least equal to or greater than 1.20.

38. Comminution device according to Claim 34, wherein the ratio (r4 - r3)/(r3 - r2) is at least equal to or greater than 1.25.

39. Acceleration device according to Claim 22, wherein said accelerator unit is provided with at least a first accelerator member and a second accelerator member that is associated with said first accelerator member for accelerating said material in two phases, which first accelerator member is provided with at least a first acceleration surface for accelerating said fed material in a first phase with the aid of guiding along said first acceleration surface, in such a way that said guided material is brought into a spiral path oriented backwards, viewed from a standpoint moving with said first accelerator member, which second accelerator member is provided with at least a second acceleration surface, that is oriented essentially transversely to said spiral path, for accelerating said guided material in a second phase by striking said second acceleration surface, the various aspects being such that said first acceleration phase takes place a shorter radial distance away from said rotor than said second acceleration phase, which occurs an appreciably greater radial distance away.

40. Acceleration device according to Claim 22, wherein said accelerator unit is provided with at least one guide member for accelerating said material in one phase, which guide member is provided with at least one guide surface that at least partially extends in the direction of said outer edge of said rotor.

41. Comminution device according to Claim 22, wherein said collision member consists of one piece.

42. Comminution device according to Claim 22, wherein said collision member consists of at least two collision elements, each of which is provided with at least one collision surface relief.

43. Comminution device according to Claim 22, wherein said rotor can be rotated in both directions, forwards and backwards, and said collision surface relief is provided with two collision surfaces for each of said directions of rotation.

44. Comminution device according to Claim 43, wherein said collision relief is mirror symmetrical with respect to a radial plane from said axis of rotation that intersects said collision surface relief in the middle between said two collision surfaces.

45. Comminution device according to Claim 22, wherein said collision surface relief is essentially of pointed construction.

46. Comminution device according to Claim 22, wherein said collision surface relief is essentially of triangular construction in a section parallel to the plane of rotation.

47. Comminution device according to Claim 22, wherein said collision surface relief is essentially of trapezium-shaped construction in a section parallel to the plane of rotation.

48. Comminution device according to Claim 22, wherein said collision surface relief is essentially of V-shaped construction in a section parallel to the plane of rotation.

49. Comminution device according to Claim 22, wherein said collision surface relief is constructed with an essentially rounded point in a section parallel to the plane of rotation.

50. Comminution device according to Claim 22, wherein said collision surface relief is essentially of semi-circular construction in a section parallel to the plane of rotation.

51. Comminution device according to Claim 22, wherein said collision surface relief is essentially of truncated V-shaped construction in a section parallel to the plane of rotation.

52. Comminution device according to Claim 22, wherein said collision surface relief is constructed with an essentially rounded shape in a section parallel to the plane of rotation.

53. Comminution device according to Claim 22, wherein said collision surface is not of straight construction.

54. Comminution device according to Claim 22, wherein said collision surface is not oriented vertically.

55. Comminution device according to Claim 22, wherein said collision surface describes an evolvent of said ejection stream.

56. Comminution device according to Claim 22, wherein the collision angle (β) between the ejection stream and said collision surface is greater than or equal to 70°.

57. Comminution device according to Claim 22, wherein said collision member is supported by said crusher housing with the aid of a support member.

58. Comminution device according to Claim 22, wherein said collision member is essentially in firm contact with said inside wall of said crusher housing.

59. Comminution device according to Claim 22, wherein said inner crusher wall is provided with a wear part that extends around said axis of rotation and is in a location between said collision member and the inner wall of said crusher housing to protect said inside wall when said collision member wears through.

60. Comminution device according to Claim 22, wherein said collision member essentially is in firm contact with said protective wall for said crusher housing.

61. Comminution device according to Claim 22, wherein said circumscribed circle is some distance away from the inside wall of said crusher housing.

62. Comminution device according to Claim 22, wherein said collision member is at least partially some distance away from the inside wall of said crusher housing, such that at least part of the side of said collision member that faces the inside wall of said crusher housing is not in contact with said inside wall, such that there is an open space all round between said collision member and said inside wall of said crusher housing, which open space can fill with own material when said collision member wears through, such that said own material protects the inside wall of said crusher housing against wear.

63. Comminution device according to Claim 62, wherein said space between said collision member and said inside wall extends all round from the plane that is essentially coincident with the plane along which said ejection stream moves in the direction of the edges of said collision member along at least part of the side of said collision member that faces said outside wall.

64. Comminution device according to Claim 62, wherein said space between said collision member and said inside wall of said crusher housing is essentially completely open, such that granular material can deposit in this space when said collision member wears through, such that said granular material protects the inside wall of said crusher housing against colliding material.

65. Comminution device according to Claim 62, wherein said collision part is provided along the side that faces the outer edge of said crusher housing with at least one spacer member in the form of at least one spacer ridge that protrudes in the direction of said outer edge and holds said collision part some distance away from said inside wall, which ridge is located along at least one of the edges of said collision part that is essentially parallel to the plane of rotation.

66. Comminution device according to Claim 62, wherein said inside wall of said crusher housing is provided with a spacer member in the form of a spacer rim that is located between the top edge of said collision member and said inside wall such that the wall of said collision member that faces the inside wall of said crusher housing is at least partially some distance away from said inside wall.

67. Comminution device according to Claim 22, wherein said support member consists of a holder for said collision member, which holder can be removed together with said collision member.

68. Comminution device according to Claim 22, wherein said support member consists of an annular plate that extends from the inside of said crusher housing in the direction of said axis of rotation, on which plate said collision member is arranged.

69. Comminution device according to Claim 22, wherein said collision element is provided with at least one connector member for connecting said collision elements to one another.

70. Comminution device according to Claim 22, wherein said collision element is provided with at least one fixing member for fixing said collision element to said support member in such a way that said collision element can be removed.

71. Comminution device according to Claim 22, wherein said collision element consists of a collision block that is provided with a strengthening member that extends along at least part of one of the sides of said collision block that does not face said axis of rotation and is firmly joined to said collision block, which strengthening member is made of a material that has an appreciably greater tensile strength than said material from which said collision block is made.

72. Comminution device according to Claim 71, wherein said strengthening member is essentially in the form of a plate, at least part of one of the plate sides of which is firmly joined to said side of said collision block.

73. Comminution device according to Claim 71, wherein said strengthening member is provided with at least one fixing member.

74. Comrninution device according to Claim 71, wherein said strengthening member is provided with at least one connector member.

75. Comminution device according to Claim 71, wherein said strengthening member is provided with at least one spacer member.

76. Comminution device according to Claim 71, wherein said strengthening member is along the side of said collision member that faces the inside wall of said crusher chamber.

77. Comminution device according to Claim 71, wherein said strengthening member is located along a side that is parallel to the plane of rotation.

78. Comminution device according to Claim 22, wherein said collision member is made of a material that is harder than said colliding material.

79. Comminution device according to Claim 71, wherein said collision block is made of a material that has a hardness greater than or equal to Rc55.

80. Comminution device according to Claim 22, wherein said collision member is provided with at least one hard metal part.

81. Device according to Claim 80, wherein hard metal is understood to be an alloy of at least one hard, wear-resistant constituent in the form of tungsten carbide or titanium carbide and at least one soft metal constituent in the from of cobalt, iron or nickel.

82. Comminution device according to Claim 22, wherein said collision member is provided with at least one ceramic part.

83. Device according to Claim 82, wherein ceramic material is understood to be a material that at least partially consists of aluminium oxide (AI2O3).

84. Device according to Claim 82, wherein ceramic material is understood to be a material that at least partially consists of silicon oxide (Si0₂).

85. Comminution device according to Claim 22, wherein said crusher housing is provided with two essentially identical collision members that extend in parallel next to one another around said axis of rotation, wherein the collision surfaces of one of said collision members are oriented essentially transversely to said ejection stream, such that said collision members can be replaced when one collision member has worn out as a result of wear.

86. Comminution device according to Claim 22, wherein said collision member is arranged in a bed of own material that extends at least between said collision member and said inside wall of said crusher housing.

87. Comminution device according to Claim 71, wherein said strengthening member and said collision block are firmly joined to one another by successively casting said strengthening member and said collision block after one another in accordance with a first production method where said strengthening member is cast using a first melt and said collision block is cast immediately thereafter, using a second melt, onto the attachment side of said strengthening member at the point in time when said first melt is still in a fluid state, or at least said attachment side is at a temperature such that complete fusion of said first and second melt takes place along said attachment side, wherein the alloys of said first and second melts are not identical, wherein the composition of said alloys is so chosen that when said accelerator member is subjected to thermal after-treatment said collision block develops the desired hardness and said strengthening member retains the desired tensile strength, wherein said attachment side describes an essentially straight surface, wherein, during the production of said collision element, said attachment side describes an essentially horizontal surface, wherein, after the strengthening member has been cast, said attachment side is first provided with a film of an agent that prevents oxidation occurring along said attachment side or at least prevents this as far as possible.

88. Comminution device according Claim 71, wherein said strengthening member and said collision block are firmly joined to one another by simultaneous casting of said strengthening member and said collision block in accordance with a second production method where said collision element, said strengthening member and said collision block part are casted simultaneously using a melt of identical composition and only said collision block is subjected to a thermal after-treatment such that said collision block acquires a greater hardness, and thus lower tensile strength, than said strengthening member.

89. Comminution device according Claim 71, wherein said strengthening member and said collision block are firmly joined to one another by casting said collision block onto at least one side of said strengthening member, wherein said collision block is cast onto a strengthening member in the form of a piece of metal plate material, wherein, before said collision block is cast, the metal plate is brought to a temperature that is approximately equal to the temperature of said melt, wherein, during the production of said collision element, an additional layer of melt material is also applied to the back of said metal plate, that is the side opposite the attachment side of said strengthening member, such that the metal plate assumes virtually the same temperature as said melt, which additional layer is then removed, for which puφose said back is provided with a film of an agent that prevents adhesion between said back and said additional layer cast on.

90. Comminution device according to Claim 71, wherein said strengthening member and said collision block are firmly joined to one another by the adhesion of said strengthening member on said collision block, wherein the adhesion along the attachment side is achieved with the aid of sintering or with the aid of soldering.

91. Comminution device according to Claim 71, wherein said strengthening member and said collision block are firmly joined to one another by casting said strengthening member in a mould, wherein said strengthening member is arranged in the mould beforehand, which mould is then filled by pouring in melt material in such a way that melt material is cast onto at least two plate surfaces of said plate, it being possible to provide the plate surfaces with an agent, or to treat these surfaces in some other way, beforehand, so that the best possible adhesion is obtained, such that, when filling by pouring in the melt material, said strengthening member is brought to a temperature that is essentially equal to that of the melt, so that no or only limited stresses arise along the attachment side during cooling, wherein the composition of said alloys of, respectively, the structural material from which the collision block is made and the structural material from which the strengthening member is made is so chosen that when said collision element is subjected to a thermal after-treatment said collision block develops the desired hardness and said strengthening member retains the desired tensile strength.