WO1996032197A1

WO1996032197A1 - Multiple rotary impact crusher

Info

Publication number: WO1996032197A1
Application number: PCT/NL1996/000154
Authority: WO
Inventors: Johannes Petrus Andreas Josephus VAN DEN ZANDEN
Original assignee: Van Den Zanden, Rosemarie, Johanna; Ihc Holland N.V.
Priority date: 1995-04-11
Filing date: 1996-04-10
Publication date: 1996-10-17
Also published as: AU5163596A; NL1000114C2

Abstract

A multiple rotary impact crusher, by means of which granular material is flung out over the edge of the rotor blade (3), following which said material strikes against an armoured ring (10) which rotates along with the rotor blade and of which the flat impact face is a conical shape, and which is disposed at such an angle that after impact the granular material is guided obliquely further downwards to a second armoured ring (13) which rotates along with the rotor blade (3) and is disposed below the edge of the rotor blade, which second ring is also equipped with a conically shaped flat face, after which impact the coarse and the fine fraction of the broken fragments can be separated from each other by means of a partition (15) which is adjustable in height and is disposed around the impact face of the second armoured ring (13), following which the coarse broken fragments which are guided over the edge of the partition strike against impact plates disposed in a stationary manner in a V-shape, during which impacts the coarse granular material is comminuted further.

Description

MULTIPLE ROTARY IMPACT CRUSHER

TECHNICAL FIELD

The invention relates to an impact crusher, having a dish-shaped rotor blade which is mounted in such a way that it is rotatable about a vertical axis, and which is provided with shorter or longer guides which are straight, curved or bent and have a smooth steel guide face, or which are in the form of a chamber vane in which granular material settles under the influence of centrifugal force when the rotor blade is turning, which granular material as such forms a natural guide face there, which guides run from the centre part in a radial or non-radial direction towards the edge of the rotor blade, and by means of which rotor blade granular material which has been taken to the centre of the rotating rotor blade, under the influence of centrifugal force, is brought to velocity along, or by a blow from, the guides and is flung outwards over the edge of the rotor blade, following which the granular material strikes against an armoured ring which is disposed around the rotor blade, during which impact the material breaks.

BACKGROUND ART

Such impact crushers, by means of which material for crushing is brought to velocity by means of a rotor blade which is provided with guides, following which the material strikes against an armoured ring disposed around the rotor blade, are known from various patent specifications.

The take-off angle of the granular material from the rotor blade normally lies between 35" and 45" in the case of the known impact crushers. After leaving the rotor blade, the granular material moves virtually in a straight line; over the short distance covered by the granular material until it strikes against the armoured ring, gravity and the rotating movement of the granules have no appreciable influence on the direction of movement. The impact angle which the granular material makes against the armoured ring is therefore determined by the take-off angle of the granular material from the rotor blade and the angle at which the impact face of the armoured ring is disposed at the position of the impact.

Such single impact crushers are known from US Patent Specifications 5,184,784 - 4,784,339 - 4,756,484 - 4,699,326 - 4,690,341 - 4,560,113 - 4,326,676 - 4,090,673 - 3,606,182 - 3,540,667 - 3,474,974 - 3,300,152 - 3,258,211 - 3,148,840 - 1,547,385 and European Patent Specifications 01 6 674 A2 and 0166 672 A2. A number of the impact crushers have a rotor blade with radially directed guides, by means of which the material for crushing is flung against an armoured ring disposed around the rotor blade, which armoured ring is composed of impact plates which are placed vertically next to each other and in the horizontal plane are rotated at such an angle that the impact occurs as vertically as possible. The armoured ring, with the projecting corners of the impact plates, consequently as a whole is a knurled shape. Most of these known impact crushers are provided with shorter guides which are disposed, radially or otherwise, along the edge of the rotor blade. Since the space between the guide strips on the rotor blade increases further towards the outside, thicker guide strips or guide blocks can be fitted in this case, which are disposed more along the edge of the rotor blade, and which have a longer service life and therefore need not be changed as often. Through the high tangential speed which these guide blocks have, and depending on the way in which the pieces of material for crushing are received by the guide blocks, the granular material is brought to velocity partly along and partly by a blow from the guides. The take-off angle and the take-off velocity, and thus the impact velocity and the impact angle, of the granular material against the armoured ring, can consequently exhibit a great spread. Compared with the abovementioned known impact crushers with long guides, the known impact crushers which are designed with guide blocks disposed towards the edge of the rotor blade therefore have an even lower breaking probability, while the spread in the quality of the crushed product increases. US Patent Specifications 4,756,484 - 4,690,341 - 4,659,026 - 4,560,113 - 4,575,014 and European Patent Specifications 0216 913 A3 - 0166 674 A2 and 0166 672 A2 disclose single impact crushers which are equipped with rotor blades provided with chamber vanes, in which the granular material settles when the rotor blade is turning and forms a natural guide face, with the result that wear is limited. The take-off velocity and the take-off angle vary very widely with these types of rotor blade, in most cases being highly tangentially directed, with the result that the breaking probability is limited, while here again the spread in quality of the crushed product increases. The problem with the known single impact crushers described above is that the comminution process takes place during a single impact which is directed as vertically as possible. Research has shown that for the comminution of material by means of impact load a vertical impact is not optimal for most materials and that, depending on the specific type of material, a greater breaking probability can be achieved at an impact angle of approximately 75", or at any rate between 70" and 85°. The breaking probability can be increased further if the product for crushing is not impact-loaded singly, but multiply, or at any rate at least doubly, in rapid succession. Furthermore, in the impact crushers described the impact of the granular material is partially greatly disrupted by the projecting corners of the impact plates. This disruptive influence can be indicated as the length which is calculated by multiplying the diameter of the pieces of material for crushing by the number of projecting corner points of the armoured ring relative to the total length or the circumference of the armoured ring. This disruptive influence increases as the corners of the impact plates become rounded through wear. The movement and the impact of the granular material are further impeded by broken fragments which, if the granular material breaks during vertical impact, fly in all directions and can consequently come between an impacting granule and the impact face of the impact plate, with the result that the full impact of the following granules is prevented. The great speed at which the rotor blade rotates also causes strong air currents and eddies to occur in the space between the edge of the rotor blade and the armoured ring disposed around the rotor blade, with the result that the progression of the comminution process is disrupted further.

The single impact, the impact angle which is vertical as far as possible, the disruptive influences of the projecting points of the armoured ring, the broken fragments flying around and the strong air current are the reasons why the breaking probability of the known single impact crushers described above is limited, while the quality of the crushed product can show great variations. In order to achieve a reasonable degree of comminution, the impact velocity must be increased, which requires additional energy, causes wear to increase, and can give rise to the occurrence of an undesirably large fine particles content.

As indicated earlier, the take-off angle of the individual granules from the edge of the rotor blade is between 35° and 45° for the known impact crushers and, depending on the specific construction of the rotor blade, is fairly constant or can exhibit a greater spread. In order to achieve the most vertical impact angle possible, the impact plates are normally disposed in the horizontal plane at an angle - measured in the horizontal centre of the impact face of the impact plate relative to the radius of the rotor blade - which is directed at right angles to the take-off path of the pieces of material for crushing. This means that the impact takes place to the left or right of the horizontal centre of the impact plate, at a slightly modified impact angle. This problem can be partially eliminated by choosing shorter impact plates, but this increases the total number of corner points of the armoured ring, or by choosing longer impact plates and making the impact faces of these longer impact plates curved - or hollow - in the horizontal plane, with such a circular arc that the impact in the horizontal plane takes place as vertically as possible. US Patent Specifications 3,150,838 - 3,110,449 - 3,093,329 - 3,074,657 - 3,044,720 - 2,844,331 and British Patent Specification 309,854 disclose such impact crushers, but they have the problem that the corners in particular wear relatively quickly, with the result that the envisaged impact geometry is changed and a partial disruption of the vertical impact pattern occurs. All known impact crushers described here exhibit fairly great wear, while the specific design oi the known impact crushers is the reason for such impact crushers being able to function only with the rotor blade turning in one direction, with the result that the wear pattern develops at one side, and the impact face changes, which can influence the progression of the comminution process, and thus the quality of the crushed product. If the guide construction on the rotor blade is radially directed and symmetrical, and the impact plates of which the armoured ring is composed are also made symmetrical, it is ensured that the rotor blade can be used rotating both clockwise and anticlockwise. With such an impact crusher the wear occurs more evenly, with the result that the guides and the impact plates are utilized better, while the progression of the comminution process, and thus the quality of the crushed product, is influenced less. Such impact crushers, which function with both clockwise and anticlockwise rotating rotor blade, are known, inter alia from British Patent Specification 394,478, from US Patent Specifications 3,873,047 and 1 ,532,742 and from European Patent Specification

0562 194 A2, in which the symmetrically knurled armoured ring still has a large number of projecting corners which disrupt the movement and the impact of the material for crushing, and the same applies to the influence of the flying broken fragments and the influence of the air movements in the crushing space which were described above. Although more advantageous as regards wear, while a crushed product of more uniform quality is produced, the breaking probability of these known impact crushers as a whole remains low.

Recapitulating, it can be said that in the known single impact crushers described here the vertical impact of the granular material against the armoured ring disposed around the rotor blade is greatly disrupted in all cases through the fact that the take-off angle from the edge of the rotor blade is not always constant, and through impact of the granules against the projecting corners of the impact plates of which the armoured ring is composed. The impact is further disrupted as the impact plates wear, in particular along the corners, while the movement and the impact of the material for crushing is impeded by flying broken fragments and air movements in the crushing space. The disruptive influences are the reason why the envisaged vertical impact is achieved only for part of the individual granules from the material for crushing. The comminution process also occurs during a single impact. For these reasons the breaking probability is low, a crushed product of variable quality is produced, the fine particles content is often undesirably high, while the energy consumption is relatively great, and great wear occurs. A greater breaking probability can be achieved only by increasing the impact velocity of the pieces of material for crushing against the impact plates, with the result that the energy consumption and the wear increase further, while even more fine parti¬ cles are possibly produced. As indicated earlier, the breaking probability can be increased considerably by subjecting the material for crushing to impacts occurring in rapid succession, or direct multiple impacts, and making the impacts occur at an impact angle or load angle which is optimum for comminution of the granular material. German Patent Specification 688 169 discloses a single impact crusher in which the impact plates of the finely knurled armoured ring, which are disposed around the rotor blade, are placed at a downward tapering angle in the horizontal plane, so that the broken fragments are deflected downwards during the impact and thereby do not impede the impact of the following granules, which promotes uniform progression of the comminution process. US Patent Specifications 3,474,974 and 1,267,110, the latter patent specification for treating nuts, disclose single impact crushers where for the same reasons the impact plates are placed with the impact face slanting slightly inwards.

US Patent Specification 5,323,974 discloses a single impact crusher in which the impact plates which are disposed around the rotor blade are adjustable in height, as a result of which the impact plates of the otherwise symmetrically designed impact crusher, which can function rotating both clockwise and anticlockwise, wear evenly.

German Patent Specifications 1 ,814,751 and 1,253,562 disclose impact crushers with rotor blades placed above one another and rotating about the same axis, the various rotor blades being fed on the centre part, and the impact of the granular material takes place against impact plates which are disposed at a downward slanting angle around the rotor blade, with the object of deflecting the crushed product downwards.

US Patent Specifications 1,911 ,193 and 1,656,756 disclose multiple impact crushers in which the granular material is flung by means of a rotor blade against an armoured ring disposed around the rotor blade, while in the vertical plane the impact face runs slightly outwards, so that the material for crushing is guided in a downward path, following which the material for crushing is received on a second rotor blade which is situated below the first rotor blade and is driven by the same shaft as the first rotor blade, with which rotor blade the material is flung against a following armoured ring which is disposed around the latter rotor blade. The multiple loading is indirect here, which is much less effective than if the multiple loading were to occur directly and in rapid succession. Besides, both rotor blades must be driven, which makes the energy consumption and the wear increase considerably. US Patent Specification 2,898,053 discloses a multiple impact crusher in which the knurled impact wall disposed around the rotor blade is continued downwards below the edge of the rotor blade, running inward slightly, while four radially directed vertical plates are fixed below the edge of the rotor blade, which plates rotate along with the rotor blade, and by means of which the granular material falling down after the first impact against the armoured ring around the rotor blade is again impact-loaded by a blow from the plates, as a result of which the granular material is flung again against the knurled outside wall of the crushing space. The multiple nature of the impact is extremely arbitrary in the case of the known crusher, while the disruptive influence is great, but as a whole the system produces a fairly high breaking probability, although the quantity of fine material can be great. US Patent Specification 3,881,664 discloses a multiple impact crusher in which the three impact walls are formed by a sort of open tube whose bottom wall is disposed slanting upwards around the rotor blade, so that immediately after the first impact the granular material is guided upwards to the adjacent impact wall which is disposed at an angle of 90° inwards relative to the first impact plate, with the result that the granular material is deflected horizontally inwards and strikes against the adjacent, third impact wall placed at right angles to the previous impact wall, during which impact the granular material is deflected downwards in a vertical direction. The successive impacts occur here at a fairly flat angle of approximately 45° in the horizontal plane and 45° in the vertical plane, as a result of which the granular material has a strong tendency to run around in the tubes, while the broken fragments leaving the tubular construction cross the path of the incoming granular material. Although the multiple nature of the impact is direct here, the very unfavourable impact angles and the disruptive influence through collision between the granules and the broken fragments are the reason for the breaking probability being limited and the quality of the crushed product varying widely; and the crusher is suitable only for surface treatment of finer granular material, for which the crusher was designed.

Patent Specification PCT WO 94/29027, which is in the Applicant's name, discloses a multiple impact crusher consisting of two casings disposed in a stationary and radial manner and being in the form of downward widening truncated cones which are placed over one another, and the diameters υi which increase downwards, in which the outer casing is disposed with the top edge around the rotor blade, and the inner casing is disposed with the top edge below the edge of the rotor blade, and in which an annular and slit-shaped crushing space is formed by the space between the two truncated cones, which space is bounded by the inside wall of the outer casing and the outside wall of the inner casing. In the known multiple impact crusher the impacts of the granular material occur in succession at fairly flat angles against the inner casing of the truncated outer cone and the outer casing of the truncated inner cone. The flat angle of impact is the reason for the granules being subject to only a limited load during the impacts, while the granules and the broken fragments resulting therefrom are guided in a downward slanting, zigzag path of multiple impact through the crushing space. In this case the granules inevitably cross each other's paths, with the result that the granules can be impeded in their movement through the crushing space and during the impact against the crushing walls. These factors are the reason why on the whole the breaking probability of the known multiple impact crusher is not entirely satisfactory.

German Patent Specification 39 05 365 Al discloses a multiple impact crusher in which the granules are guided from the rotor blade between crushing plates, which are in the form of impact strips and which in the horizontal plane of the rotor blade are disposed in a stationary manner and are directed radially outwards, with the result that the impact strips form a sort of fan. After leaving the edge of the rotor blade, the granules are guided in a zigzag path of multiple impact between the strips, during which impacts the granules break. However, this known impact crusher has the problem that the many corners of the crushing plates, which face the rotor blade, constitute a very great disruptive influence for the flying granular material, with the result that only a limited part of the individual granules is guided out of the material for crushing unimpeded into the envisaged path of multiple impact. A large part of the granules from the material for crushing is disrupted in its movement by the points of the impact strips, while the granules are slowed down further in the horizontal plane between the crushing plates through friction with the bottom plate of the crushing space. The breaking probability consequently remains limited, while there is a wide spread in the quality of the crushed product. Moreover, owing to the specific asymmetrical shape of the impact strips, the crusher can function with the rotor blade in only one direction of rotation, with the result that the wear is unevenly distributed.

Patent Specification DD - PS - 16983 discloses an impact mill in which the crushing space is formed by the ring and the slit-shaped space between two casings placed over one another and being in the form of downward widening truncated cones. Strips running vertically from the top downwards along the walls are disposed along both the inside and the outside wall of the crushing space. The comminution process is achieved in the crushing space through the fact that the inner cone rotates, with the result that the granular material fed from the top into the crushing space is brought to velocity by the strips fitted on the wall of the rotating inner cone and are flung outwards, where the granules subsequently strike against the strips which are fitted against the inside wall of the outer cone, which is disposed in a stationary manner. In this case the material for crushing can pass between the strips rotating directly over one another, with the result that a large part of the material for crushing is pulverized. This means that it is more a question of grinding than crushing. The impact mills described, which are subject to great wear, deliver a ground product with in particular a large fine particles content, while the quality of the ground product as a whole can show great variations.

DE - C - 942,244 discloses a similar type of impact mill, in which the crushing space is likewise formed by the space between two casings placed over one another, and the diameter of which increases towards the bottom.

All known single and multiple impact crushers described here have the problem that the movement of the granular material in the crushing space is impeded, while the impact of the granules is disrupted, with the result that the comminution process is not consistent, which is the reason why the breaking probability is relatively low and the quality of the crushed product can vary widely. DISCLOSURE OF INVENTION

The object of the invention is to design the impact crusher in such a way that each of the granules from the material for crushing passes along a geometrically virtually identical and independent or individual crushing path of multiple impact, with optimum impact angles for comminution of the material for crushing, while the granular material and the broken fragments resulting therefrom impede each other as little as possible, with the result that the breaking probability is increased considerably compared with the known impact crushers, so that less comminution energy is required, wear is limited, and a crushed product of consistent quality with the smallest possible quantity of undesirable fine particles is produced, while the coarse and fine fractions of the crushed product can be separated from each other the crusher.

To this end, the invention makes provision for the impact crusher to be provided with two flat armoured rings, of which one is disposed radially around the rotor blade and one below the edge of the rotor blade, and in which neither of the armoured rings is disposed in a stationary manner, but both rotate with the rotor blade, while an annular partition which is adjustable in height and rotates along with the rotor blade or is disposed in a stationary manner is placed along the outside or around the impact face of the second armoured ring. The impact faces of the armoured rings form such an angle in the vertical plane that, after the impact against the first armoured ring, the granular material is deflected in such a rebound direction that the granular material is guided in a radial and downward slanting path to the impact face oi the second armoured ring, where the impact face in the vertical plane forms such an angle that the material is guided further in a radial and downward slanting and outward directed vertical plane, while the respective angles of impact which the individual granules form against the impact faces of the armoured rings lie between 70" and 85"

At the moment when they leave the rotor blade the individual granules from the material for crushing have a velocity vector which is composed of a radial and a tangential component which, assuming that the material for crushing leaves the rotor blade at a take-off angle of approximately 45", each travel at the same velocity, which is approximately 70% of the vector velocity During the impacts against the simultaneously rotating armoured rings only the radial velocity component is active, and the tangential velocity component is retained This means that after leaving the rotor blade - viewed from the rotating position - the individual granules from the material for crushing pass between the armoured rings placed staggered below one another, and each follow a zi zag path of multiple impact, running in a radial plane vertically downwards, against the impact faces of the successive armoured rings, in the course of this the granules do not impede each other in their movement and during the impacts

The invention provides for the guides on the rotor blade to be of radial and symmetrical design, so that as a whole an impact crusher with a symmetrical construction is produced, with the result that the impact crusher can function rotating both clockwise and anticlockwise, as a result of which an even wear pattern is achieved. When the granules break, the coarser broken fragments rebound at a greater angle than the finer broken fragments, which rebound at a flatter angle. The very finest broken fragments rebound at a very flat angle, more or less along the impact face. There is therefore a sort of rebound fan of broken fragments, with the coarse broken fragments, directed more horizontally, in the top of the fan, and the finer broken fragments, directed more vertically downwards, in the bottom of the fan. By now placing a circular partition which is adjustable in height and is stationary or rotates along with the rotor blade, around the impact face of the second armoured ring, the top edge of which partition intersects the rebound fan, the broken fragments situated in the top of the rebound fan are guided over the partition and thus separated from the broken fragments which are situated below them in the rebound fan and which are deflected downwards along the front of the partition. A rough separation is thus made between the coarse and the fine fractions of the broken fragments; and the coarse fraction could possibly also contain granular material not yet crushed. At the moment when the granular material, following impact against the last or bottom armoured ring, leaves the rotating crushing space along the partition, the granules have each built up a velocity vector which is composed of the original tangential velocity component and the part of the radial velocity component which is still active after the two impacts. The absolute velocity of the broken fragments at the moment when the granules rebound towards the second impact is thus greater than the radial velocity component alone at which the granule fragment struck against the first armoured ring. Since the tangential velocity component is dominant, the take-off angle in the horizontal plane is highly tangential in direction. The considerable quantity of movement energy still stored in the granules is now utilized by making the granules strike against stationary impact plates at the most advantageous angle possible. This is achieved in the invented impact crusher by making the coarse broken fragments, which are guided over the first-mentioned partition, now strike, in the downward slanting movement plane along which the broken fragments are moving, against stationary impact plates which are disposed in a V-shape in the movement plane of the broken fragments, and which are disposed next to each other facing outwards, with the points in the direction of the flving broken fragment pieces. The broken fragments strike against the flanks of the V-shaped impact plates, the angle which the flanks of the V-shaped impact plates form being selected in such a way that the pieces of material for crushing make their impact at a load angle of 70" to 80" which is as advantageous as possible. Some of the granules strike against the points of the V-shapes. The granules must be prevented from striking against the flanks of the V-shapes not facing the flying path. Assuming that the take-off angle of the granular material from the edge of the rotor blade is maximum 30°, this means that the V-shaped point, by means of which the impact plates are disposed in the direction of the armoured ring must form an angle of less than 90°. The impact plates disposed symmetrically in a V-shape make it possible for the invented impact crusher to function rotating both clockwise and anticlockwise.

The invention provides the possibility for the crusher to be designed with a single or a third armoured ring in which the partition and the impact plates of the stationary crusher disposed in a V-shape are disposed facing inwards. The impact crusher with a single armoured ring permits a very compact construction; with three armoured rings the breaking probability is increased, but the size of the construction increases. The choice of the number of armoured rings is determined partly by the hardness of the material for crushing.

The invention also provides the possibility for the rotating armoured rings and the stationary crushing ring to be jointly or individually adjustable in height, while the armoured rings are rotatably adjustable jointly or individually relative to the rotor blade also in the horizontal plane, so that through regular adjustment of the impact plates and the rotor blade, the wear on the impact faces of the armoured rings is as even as possible.

The invention also provides the possibility for the guides on the rotor blade to be in the form of chamber vanes in which granular material settles in the chambers under the influence of centrifugal force when the rotor blade is turning, and a natural guide face along which the remaining pieces of material for crushing are brought to velocity is produced, with the result that the wear on the guides is reduced considerably. In this case the invention provides for the design of the chamber vanes to be symmetrical, so that, with radial arrangement of the chamber vanes, the impact crusher, also with the chamber vane design, can function rotating both clockwise and anticlockwise.

In order to limit the influence of the air currents which arise through the rapidly rotating movement of the rotor blade and can influence the movement of the pieces of material for crushing in the space between the edge of the rotor blade and the armoured ring, the invention provides for the rotor blade and the armoured rings surrounding it and the partition to be mounted in a housing which rotates along with the rotor blade and the armoured rings and is the shape of a flat drum having in the centre of the top face an opening through which the material for crushing is deposited by means of a hopper on the centre part of the rotor blade, and in the bottom face is provided with outlet openings which are situated below the points of the edge of the rotor blade along which the material for crushing leaves the rotor blade, while the crushing space is divided into a number of chambers by means of partitions which are disposed between the guides and run into the bottom of the crushing space, so that as a whole the occurrence of air movements is prevented as far as possible. The partitions are situated in the crushing space in such a way that they do not impede the vertical and rotatable adjustment of the armoured rings and the partition.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1. Very diagrammatic cross-section of the multiple rotary impact crusher with two armoured rings, in which the main parts are indicated. Figure 2. Longitudinal section of the multiple rotary impact crusher with two armoured rings according to Figure 1. Figure 3. Longitudinal section of the multiple rotary impact crusher with two armoured rings according to Figure 1. Figure 4. The angle (α) which the impact face of the first armoured ring makes in the vertical plane. Figure 5. The angle (β) which the impact face of the second armoured ring makes in the vertical plane.

Figure 6. The angle (γ) which the stationary impact faces disposed in a V-shape make in the horizontal plane.

DETAILED DESCRIPTION Figure 1 is shown twice, for better comprehension of the respective longitudinal sections. Figures 1 to 3 show a crusher housing (7) in which a rotor blade (3) is disposed in the centre. The granular material is metered through the inlet (8) in the centre (4) of the rotor blade (3) and from there, under the influence of centrifugal force, brought to velocity along the guides (6), following which the granular material is flung out at great velocity over the edge (5) of the rotor blade (3).

The granular material subsequently strikes against the impact face (11) of a flat armoured ring (10) which is disposed around the rotor blade (3) and rotates along with the rotor blade (3), and which is designed as a conical ring in which the angle (α) of the impact face (11 ) in the vertical plane is chosen in such a way that the impact occurs at a load angle between 70" and 85", at which angle (α) the impact face (11) of the first armoured ring (10) is disposed. The co-rotating impact face (11) makes it possible to utilize only the radial velocity component of the velocity vector which the material has at the moment that it leaves the crushing space. Viewed from the co-rotating position, there is a radial outward movement of the granular material from the edge (5) of the rotor blade (3), so that the impact against the impact faces (11 ) of the impact plates (10) also occurs radially, and after impact the granular material rebounds in the radial direction and travels downwards at an angle. The granular material is now received by the impact face (14) of a second armoured ring (13), of which the angle (a) in the radial plane lies between 70' and 110°, which angle is selected in such a way that the impact occurs at the most advantageous load angle possible, between 70° and 85°, and the granular material is guided further radially outwards and further in a vertical plane downwards. The rotor blade (2) and both armoured rings (10, 13) can be disposed in the crusher housing (7) in a co-rotating crushing space (9) enclosing the rotor blade (3) and the two armoured rings (10; 13) This produces a dish-shaped, shut-off crushing space (23) which aerodynamically is particularly advantageous when the entire system is rotating at great speed In the top plate (24) of the rotating crushing space (23) an opening (25) is provided in the centre, in which opening a stationary casing (8) is freely suspended, and through which the granular material is metered onto the centre part (4) of the rotor blade (3) The slanting bottom plate (22) along the bottom edge of the rotating crushing space (23) which shuts off the space below the two impact rings (10, 13) is provided with openings (20) through which the broken fragments leave the rotating crushing space (23) Said openings (20) are situated below the points along which the granular material leaves the rotor blade (3), or below the ends of the guides (6) For good wear distribution it is necessary for the armoured rings (10, 13) to be adjustable both in height and rotatably relative to the rotor blade (3)

In order to limit the air movements in the crushing space (23) of the rotating crusher housing (9), partitions (21 ) can be disposed between the guides (6), which partitions run into the bottom of the crushing space (24), and by means of which the crushing space (23) is divided into number ot crushing chambers, one per guide (6)

When the material lor crushing leaves the rotating crusher housing (9) through the openings (20) in the bottom plate (23), the material is still travelling at considerable velocity, the tangential velocity component is still completely intact, as is a part of the radial velocity component The granular material moves outwards, viewed now from the stationary position, at a fairly tangential angle, measured in the horizontal plane, of between 20 and 30 , while the movement is directed slightly obliquely downwards A partition (15) is now disposed on the outside, along the bottom of the rotating crusher housing (9) The broken material can now be graded roughly, because the granules, when they break, develop a certain rebound pattern which is the shape of a sort of fan of broken fragments with the coarse fraction and the unbroken or only partially broken granules in the top of the fan, and the fine fraction lower down in the fan This partition (15) is interesting in particular because with it the granules which have not been broken can be separated in a simple manner tro the broken product The coarse fraction which is guided over the partition (1 ) now strikes against impact plates (17) which are disposed in a stationary manner in a V-shape on the outside around the partition (15), and the impact occurs against the Hanks (18) which face the flying granules and broken fragments The granules must be prevented from striking against the other flank (19) of the impact plates (17) disposed in a V-shape, because this would then be a deflecting partition which only slows down the velocity. The angle (γ) between the V-shape must therefore be chosen at less than 90°.

The construction of the rotating multiple impact crusher can be made fully symmetrical, so that the rotating crusher housing (9) with the rotor blade (3) can function rotating both clockwise and anticlockwise.

Claims

1 Multiple rotary impact crusher, having a dish-shaped rotor blade which is mounted in such a way that it is rotatable about a vertical axis, and which is provided with shorter or longer guides which are straight, curved or bent and have a smooth steel guide surface, or which are in the form of a chamber vane in which granular material settles under the influence of centrifugal force when the rotor blade is turning, which granular material as such forms a natural guide face, which guides run from the centre part in a radial or non-radial direction towards the edge of the rotor blade, and by means of which rotor blade granular material which has been taken to the centre of the rotating rotor blade, under the influence of centπhigal force is brought to velocity along, or by a blow from, the guides and is flung outwards over the edge of the rotor blade, which granular material subsequently strikes against the impact face of a flat armoured ring which is disposed around the rotor blade, the impact face of which armoured ring faces inwards and is a conical shape, and after this impact is guided further in the direction of the impact face of a flat armoured ring disposed below the edge of the rotor blade, the impact face of which armoured ring faces outwards and is a conical shape, during which impacts the material breaks, characterized in that the two armoured rings (10; 13), which are disposed around (10) the rotor blade (3) and around (13) the outside edge (5) of the rotor blade (3) respectively, rotate along with the rotor blade (3) at the same angular speed

2 Multiple rotary impact crusher according to Claim 1 , characterized in that the impact face (11 ) of the first armoured ring (10), which is disposed around the rotor blade (3), is a conical shape, while the impact face (11 ) forms an angle (α) of between 70° and 85^l in the radially directed vertical plane relative to the axis (1 ) of the rotor blade (3)

3 Multiple rotary impact crusher according to Claims 1 and 2, characterized in that the impact face (14) oi the second armoured ring (13), which is disposed below the edge (5) of the rotor blade (3) ι-. a conical shape, and forms an angle (β) between 70° and 110" in the radially directed vertical plane relative to the axis (1 ) of the rotor blade (3) 4 Multiple rotary impact crusher according to Claims 1 to 3, characterized in that the rotor blade (3) and the armoured rings (10, 13) are mounted in a housing (9) which rotates u ith the rotor blade (3) and the armoured rings (10, 13) and is the shape of a flat, dish-shaped drum, having in the centre of the top side (24) an opening (25) through Inch the material for crushing is metered onto the centre part (4) of the rotor blade (3) through a casing (8) hanging freely in said opening (25) above the central part

(4) of the rotor blade (3), and having in the bottom (26) a number of openings (20) along which the material from the rotating crushing space (23) is guided, which openings (20) are situated below the points (6) on the edge (5) of the rotor blade (3) along which the material for crushing leaves the rotor blade (3), while partition faces (21) are disposed between the guides (6) on the rotor blade (3) and run into the bottom of the crushing space (23).

5. Multiple rotary impact crusher according to Claims 1 to 4, characterized in that the armoured rings (10; 13) can be adjusted jointly or individually, in height, parallel to the axis (1 ) of the rotor blade (3) and rotatably, radially about the axis (1) of the rotor blade (3).

6. Multiple rotary impact crusher according to Claims 1 to 5, characterized in that an annular partition (15) which is adjustable in height, parallel relative to the axis (1 ) of the rotor blade (3), is placed along the front or radially outside around the impact face (14) of the second armoured ring (13).

7. Multiple rotary impact crusher according to Claims 1 to 6, characterized in that a stationary crushing space (27) is situated on the outside radially around the partition (15), which space is adjustable in height, parallel relative to the axis (1) of the rotor blade (3), and consists of elongated impact plates (17) which are disposed symmetrically adjacent to each other in a V-shape and are d irected with the V-shaped points radially towards the impact face (14) of the second armoured ring (13), so that the entire system is an outward and slightly downward directed symmetrical fan shape, against the impact faces (18; 19) oi which impact plates (17) the material for crushing conveyed over the partition (15) strikes and breaks further in the process.

8. Multiple rotary impact crusher according to Claims 1 to 7, characterized in that the radially inward directed V-shaped points which are formed by the impact plates (17) of the stationary crushing ring (27) form an angle (γ) of less than 90°.

9. Multiple rotary impact crusher according to Claims 1 to 8, characterized in that the guides (6) on the rotor blade (3) are radially d irected and symmetrical, so that the multiple impact crushers can function rotating both clockwise and anticlockwise.

10. Multiple rotary impact crusher according to Claims 1 to 9, characterized in that the multiple rotary impact crusher is designed with one armoured ring (10) which is disposed with the impact face facing inwards around the rotor blade (3).

11. Multiple rotary impact crusher according to Claims 1 to 9, characterized in that the multiple rotary impact caisher is equipped with a third armoured ring which is disposed with the impact face facing inwards along the bottom of the inside of impact face (14) of the second armoured ring (13).

12. Multiple rotary impact crusher according to Claims 10 and 11 , characterized in that an annular partition which is adjustable in height, parallel relative to the axis (1) of the rotor blade (3), is placed along the front or radially inside the impact face of the first or the third, or in any case the bottom armoured ring.

13. Multiple rotary impact crusher according to Claims 10 to 12, characterized in that a stationary crushing space is situated radially along the inside of the partition, which space is adjustable in height, parallel relative to the axis (1) of the rotor blade (3), and consists of elongated impact plates which are disposed symmetrically in a V-shape and are directed with the V-shaped points radially towards the impact face of the bottom armoured ring, so that the entire system is an inward and slightly downward directed symmetrical fan shape.