Scraper device for roller crusher, roller crusher and operation method thereof

Abstract

The invention provides a scraper device for a roller crusher, a roller crusher and an operation method of the roller crusher. The scraper device comprises a rotatable multi-head scraper unit having at least two scrapers which are arranged tangentially around the rotatable multi-head scraper unit at respective radial distances from the axis of rotation thereof. The squeegee device further comprises a rotary actuator arranged to selectively rotate the rotatable multi-head squeegee unit to permit operative use of one of the at least two squeegees at a time. The scraper device further comprises at least one braking device configured to prevent and / or limit rotation of the rotatable multi-head scraper unit during operation of one of the at least two scrapers. The at least two blades each comprise a scraping element having a scraping surface, where the scraping surface comprises polycrystalline diamond (PCD), the rotatable multi-head blade unit being constructed and arranged such that each scraping surface at least partially faces a tangential direction defined at the blade surface and oriented along a reference direction of rotation of the rotatable multi-head blade unit.

Description

Technical Field

[0001] The present disclosure relates to a scraper arrangement for a roller crusher, a roller crusher having two substantially parallel rollers and a method for operating the roller crusher, wherein the roller crusher comprises a flange attached to at least one end of one of the rollers. Background Art

[0002] When crushing or grinding rocks, ores, cement clinker and other hard materials, a roller crusher can be used, which has two approximately parallel rollers that rotate in opposite directions and are separated by a gap. The material to be crushed is then fed into the gap. A roller crusher is called a high-pressure grinding roller or a high-pressure roller crusher. This type of comminution has been described in US4357287, in which it has been determined that when trying to achieve fine and / or very fine comminution of materials, it is actually not necessary to strive for individual particle breakage. On the contrary, it has been found that by introducing sufficiently high compression forces so that briquetting or agglomeration of particles occurs during comminution, significant energy savings and increased production can be achieved. This crushing technology is called intergranular crushing. Here, the material to be crushed or shredded is not only crushed by the crushing surface of the roller, but also by the particles in the material to be crushed, and is therefore named intergranular crushing. US4357287 points out that this "agglomeration" can be achieved by using higher compression forces than before. For example, previously up to 200kg / cm 2 The solution in US4357287 suggests using at least 500kg / cm 2 And up to 1500kg / cm 2 In a roller crusher with a roller diameter of 1 meter, 1500kg / cm 2 This translates into forces greater than 200,000 kg per meter of roller length, whereas previously known solutions could and only could achieve a fraction of these forces. Another characteristic of inter-particle crushing is that the roller crusher should be fed with the material to be crushed in a choke feed, which means that the gap between the two opposing rollers of the roller crusher should always be filled with material along its entire length, and there should also always be material filled to a certain height above the gap to always keep the gap full and maintain a state of particle-to-particle compression. This will increase the yield and reduce it to finer materials. This is in sharp contradiction with earlier solutions, which always emphasized that single particle rupture was the only way to obtain fine and very fine particle comminution.

[0003] In contrast to some other types of crushing equipment (e.g. screens), inter-particle crushing has the characteristic that it does not produce a series of shocks and widely varying pressures during use. Instead, equipment using inter-particle crushing works with very high, almost constant pressure on the material in the gap between the rollers and in the crushing zone formed around the gap.

[0004] In order to maintain the crushing effect along the entire length of the grinding roller, flanges can be arranged at the ends of the crushing rollers; one flange is arranged at each end of one roller, or one flange is arranged at one end of each roller, but located on opposite ends of the roller crusher. With this arrangement, a more efficient and uniform roller feed inlet can be produced. The flanges will allow such a feed that a preferred material pressure is generated over the entire length of the crushing roller. It has been shown that the production capacity of a given roller crusher can be increased by up to 20%, and sometimes even more, by using flanges. A general problem associated with grinding rollers without flanges is that the ratio between the roller diameter and the roller width is very important due to the significant edge effect (i.e., the crushing result at the edge of the roller is reduced). This is because the material may overflow from the edge of the roller, thereby reducing the crushing pressure on the material towards the gap at the edge of the roller. Therefore, in the absence of flanges, it is necessary to recover the material escaping from the roller and some of the material that has passed through the gap at the edge of the crushing roller due to reduced rupture caused by the lower pressure at the edge.

[0005] However, during operation of a grinding mill having flanges, the flanges and the edges of the opposing crushing rollers are subject to significant stress and wear, and build-up material will accumulate at the transition between the crushing roller surface and the flanges. This excess build-up material needs to be continuously removed during operation of the grinding mill.

[0006] The prior art has proposed a scraper element for removing accumulated material in the transition between the crushing roller surface and the flange, see for example AU2018264756 or US5054701.

[0007] Starting from this, an object of the present disclosure is to provide a scraper device and a roller crusher including such a scraper device, which have a reduced maintenance time. Another object of the present disclosure is to provide a scraper device and a roller crusher including such a scraper device, which have a simplified procedure for replacing the scraper. Summary of the invention

[0008] According to a first embodiment of the present disclosure, this object and other objects are fully or at least partially achieved by a scraper device for a roller crusher, the scraper device comprising a rotatable multi-head scraper unit having at least two scrapers, the at least two scrapers being tangentially arranged around the rotatable multi-head scraper unit at respective radial distances from the axis of rotation of the rotatable multi-head scraper unit. The scraper device also comprises a rotary actuator and at least one braking device, the rotary actuator being arranged to selectively rotate the rotatable multi-head scraper unit to allow one of the at least two scrapers to be used operatively at a time, the braking device being configured to prevent and / or limit the rotation of the rotatable multi-head scraper unit during operation of one of the at least two scrapers. Each of the at least two scrapers comprises a scraping element having a scraping surface, the scraping surface comprising polycrystalline diamond (PCD), and the rotatable multi-head scraper unit is constructed and arranged so that each scraping surface at least partially faces a tangential direction defined by the scraper surface and oriented along a reference rotation direction of the rotatable multi-head scraper unit.

[0009] With regard to the statement "each scraping surface at least partially faces a tangential direction defined by the scraper surface and oriented along the reference rotation direction of the rotatable multi-head scraper unit", it means that the scraping surface has a projection greater than zero in a plane orthogonal to the tangential direction. As is easily understood by a person skilled in the art, this achieves the effect that, when the scraper device is arranged on a roller crusher, the scraping surface of the active scraper can be arranged so that it at least partially faces the material to be removed. Since each scraper surface is arranged in approximately the same way along the reference rotation direction, when the scraper having each scraping surface is the active scraper, each scraping surface can at least partially act as an impact surface. The scraping surface can be planar or non-planar. If the scraping surface is planar, its normal can be parallel to or substantially parallel to the tangential direction. However, if the scraping surface is non-planar, its normal can alternatively form an acute angle with the tangential direction. As will be readily appreciated by a person skilled in the art, both alternatives achieve a non-zero projection in a plane orthogonal to the tangential direction and both alternatives achieve the effect that, when the scraper arrangement is arranged on a roller crusher, the scraping surface of the active scraper can be arranged such that it at least partially faces the material to be removed. The reference direction of rotation is to be understood only as a reference. Thus, even if the rotatable multi-head scraper unit can be rotated along the reference direction of rotation in order to replace a worn scraper with a new scraper as the active scraper, it is also conceivable that the rotatable multi-head scraper unit can be rotated opposite to the reference direction of rotation in order to replace a worn scraper with a new scraper as the active scraper.

[0010] The first advantage of having a scraping surface comprising polycrystalline diamond (PCD) is that the wear life of the scraper blade is significantly extended. Typically, such scraping surfaces will include a wear-resistant material such as ceramic or a composite material containing tungsten carbide, titanium carbide or vanadium carbide, but using a scraping surface comprising polycrystalline diamond (PCD), the wear life can be extended by up to about 50 times compared to a composite material containing, for example, tungsten carbide alone.

[0011] It is conceivable to provide other surfaces of the scraper element with polycrystalline diamond (PCD). For example, the side surface of the scraper element may include polycrystalline diamond (PCD). In other words, the scraping surface can be extended to also include the side surface of the scraper element. Therefore, it should be understood that the concepts of the present disclosure should not be interpreted as being limited to scrapers whose only forward surface includes polycrystalline diamond (PCD).

[0012] According to one embodiment, the scraper element further comprises a wear resistant material at least partially embedded with polycrystalline diamond (PCD).

[0013] In an alternative embodiment, polycrystalline diamond (PCD) may be adhered to the surface of the wear resistant material of the blade.

[0014] Wear-resistant materials may include ceramic materials such as titanium carbide, vanadium carbide or tungsten carbide; metal-ceramic composites such as cemented carbides (cemented carbides), such as titanium carbide, tungsten carbide or vanadium carbide, with cobalt as a binder; or metal matrix composites including titanium carbide, tungsten carbide or vanadium carbide.

[0015] In one embodiment, the wear resistant material is a cemented carbide including tungsten carbide and cobalt as a binder, wherein the binder content may be 10-15 weight percent (wt %).

[0016] In one embodiment, polycrystalline diamond (PCD) is embedded in tungsten carbide, vanadium carbide, or titanium carbide.

[0017] According to one embodiment, the scraping surface of the scraper element may include a layer of polycrystalline diamond (PCD). The layer of polycrystalline diamond (PCD) may have a thickness of 0.4 to 3.2 mm, or 1.0 to 2.0 mm, or 1.35 to 1.8 mm, or 1.4 to 1.6 mm, or about 1.5 mm.

[0018] According to one embodiment, the scraping surface of the scraper element may include two or more layers of polycrystalline diamond (PCD). The two or more layers may be attached to each other, for example, by an adhesive. The number of layers and / or the thickness of each layer may depend on the particle size and / or the application in which it is used.

[0019] The diamond grain size of the polycrystalline diamond (PCD) of the impact surface may be 0.8 to 30 μm, which is determined by image analysis using a scanning electron microscope (SEM).

[0020] The particle size of the diamond can be measured by various measurement techniques such as a laser particle size analyzer or a scanning electron microscope (SEM). An example of a laser particle size analyzer is a Malvern particle size analyzer device based on laser diffraction. The value determined using the laser particle size analyzer can be the initial diamond particle size, which for some embodiments can then be subjected to high pressure and high temperature sintering. When the diamond particles have been sintered and compacted to form a polycrystalline diamond (PCD) that impacts the surface, image analysis by means of a scanning electron microscope is used to determine the final microstructure particle size distribution, i.e., the diamond particle size of the polycrystalline diamond (PCD) that impacts the surface.

[0021] One advantage of the disclosed scraper arrangement is that the arrangement enables a compact scraper arrangement, which reduces the space required for assembly to a roll crusher. Another advantage is that it reduces maintenance time for replacing worn scrapers, wherein an unused new scraper on a rotatable multi-head scraper unit can be simply repositioned to an operating position by rotating the rotatable multi-head scraper unit, without having to completely shut down the roll crusher for scraper replacement. Another advantage of the scraper arrangement is that it allows for an easier replacement procedure once a scraper replacement is required. The rotatable multi-head scraper unit can be prefabricated and preassembled, so that the replacement procedure can be limited to removing the old rotatable multi-head scraper unit and attaching a new rotatable multi-head scraper unit in its place, thus effectively replacing two or more individual scrapers in one replacement operation.

[0022] Another advantage is that the rotatable multi-head scraper unit allows a fully automated scraper replacement procedure. Compared to the prior art solutions, the rotary actuator can be actuated by a drive unit (e.g., a motor) that can be controlled by a control system. Thus, the scraper device contemplated by the present disclosure allows the replacement of worn scrapers without manual intervention by an operator.

[0023] Another advantage of the scraper device is that the rotatable multi-head scraper unit allows the distance between the scraper performing the scraping operation (referred to herein as the "scraper in operation") and the envelope surface of the roller to be adjusted by adjusting the angular position of the rotatable multi-head scraper unit. This built-in (built-in, inherent) adjustment capability of the scraper device can allow the thickness of the accumulated material allowed to remain on the envelope surface of the roller to be adjusted. It can also eliminate the need to mount all scrapers on the rotatable multi-head scraper unit in a manner with exactly the same radial distance from the axis of rotation. In addition, it can allow compensation for scraper wear, which will be described in detail later.

[0024] The term "brake device" used herein should be interpreted broadly. The term is used here to represent any arrangement that is constructed and arranged to prevent and / or limit the rotation of the rotatable multi-headed scraper unit during the operation of one of the at least two scrapers. Therefore, the term "brake device" naturally includes typical braking systems, such as friction brakes and clutches. However, the term "brake device" must also be interpreted as including mechanical systems, such as gear trains and any other mechanical linkage devices, whether or not they are used to perform additional tasks in the device, and are also constructed and arranged to prevent and / or limit the rotation of the rotatable multi-headed scraper unit during the operation of one of the at least two scrapers. The "brake device" can be configured to prevent and / or limit the rotation of the rotatable multi-headed scraper unit to varying degrees. Some brake devices contemplated by the present disclosure can be configured to provide a reaction torque on the rotatable multi-headed scraper unit that is strong enough to prevent its undesired rotation during normal operation, but is still selected to allow the rotatable multi-headed scraper unit to rotate in the event that excessive accumulated material impacts the scraper of the rotatable multi-headed scraper unit. This can be advantageous because it provides a means of releasing the rotatable multi-head squeegee unit from the operating position in the event that the impact force is high enough to damage the squeegee arrangement. That is, it is also conceivable that the "braking device" contemplated by the present disclosure is configured to lock the rotatable multi-head squeegee unit in its operating position by a locking engagement.

[0025] As will be readily understood by a person skilled in the art, the rotation of the rotatable multiple scraper unit is provided for repositioning the individual scrapers of the rotatable multiple scraper unit relative to the roller surface. This means that during the scraping operation, the rotation of the rotatable multiple scraper unit is not performed. In other words, the scraper device is configured to prevent and / or limit the rotation of the rotatable multiple scraper unit during the crushing operation so as to be stationary relative to the roller crusher.

[0026] According to one embodiment, the rotatable multi-head squeegee unit is arranged at a first end of the squeegee device and the rotary actuator is arranged at an opposite second end of the squeegee device, and wherein the rotatable multi-head squeegee unit extends in a reference plane orthogonal to the rotation axis.

[0027] According to one embodiment, each of the at least two scrapers has a surface facing the rotary actuator, which surface includes polycrystalline diamond (PCD). Similar to the polycrystalline diamond (PCD) on the scraping surface, also on this surface facing the rotary actuator, the polycrystalline diamond (PCD) can be at least partially embedded in the wear-resistant material as described above.

[0028] According to one embodiment, each scraping surface of the at least two scrapers is arranged to be inclined relative to the normal to the reference plane, as defined in front of the scraping surface, and the inclination is such that the distance between the normal and the scraping surface decreases towards the rotary actuator. The advantage of the scraping surface having such an arrangement is that, with the scraper device arranged and operated in a roller crusher, the material removed from a position in the corner formed by the outer surface of the roller and the inner surface of the flange will tend to flow along this surface facing the flange, and as the distance away from the scraping surface and downstream of the scraping surface increases, the removed material will be allowed to be removed towards the center of the roller, rather than being squeezed and compacted between the scraper and the inner surface of the flange. The normal is defined as a straight line orthogonal to the reference plane.

[0029] According to one embodiment, the scraping surface may be substantially flat. Therefore, according to this embodiment, the varying distance as described above may be further expressed as an angle α defined between the scraping surface and the normal to the reference plane, wherein the angle α is defined in a tangential plane of the scraper orthogonal to the reference plane. The angle α may be 1° to 15°, or 2° to 10°, or 3° to 8°, or 4° to 6°, or 5°.

[0030] A "tangential plane of the scraper blade" is herein understood to mean a plane parallel to the tangential direction of the scraper blade, as defined at the scraper blade surface and oriented along a reference rotation direction of the rotatable multi-head scraper blade unit, and which plane is orthogonal to the reference plane. Thus, each of the at least two scrapers has an associated tangential plane, which are all angled relative to each other as the scrapers are arranged tangentially around the rotatable multi-head scraper blade unit.

[0031] According to one embodiment, each of the at least two scrapers has a surface facing the rotary actuator, which surface has an extension (extension) from the scraping element tangentially towards its rear end, wherein the scraper is constructed and arranged so that the distance between the surface facing the rotary actuator and the rotary actuator decreases towards the scraping element over at least a portion of the extension. The expression "the surface has an extension from its scraping element tangentially towards its rear end" means that the scraper has an extension on the back side of the scraper element. When the scraper device is arranged on a roller crusher, the surface facing the rotary actuator will therefore be located downstream of the scraping surface for the active scraper. Therefore, the expression "extension along the tangential direction..." should be interpreted broadly and be interpreted as including any surface having an extension or dimension that is substantially parallel to the tangential direction at the position of the scraper element. The extension does not have to be the main extension of the scraper, which will be further described in the permissible disclosure. The advantage of providing such an arrangement for the surface facing the rotating actuator is that, when the scraper device is arranged and operated in a roller crusher, as the distance between the inner surface of the flange and the rotatable multi-head scraper unit increases away from the scraper surface and toward its rear end, material removed from a position in the corner formed by the outer surface of the roller and the inner surface of the flange will be allowed to be easily removed and flow toward the center of the roller, rather than being squeezed and compacted between the rotatable multi-head scraper unit and the inner surface of the flange.

[0032] According to one embodiment, the surface facing the rotary actuator is substantially flat. Therefore, according to this embodiment, the varying distance as described above can be further expressed as an angle β defined between the surface facing the rotary actuator and the reference plane, wherein the angle β is defined in a tangential plane of the scraper orthogonal to the reference plane. The angle β can be 1° to 45°, 1° to 40°, 1° to 30°, 5° to 25°, or 5° to 20°, or 5° to 15°, or 8° to 12°, or 10°.

[0033] According to one embodiment, each of the at least two scrapers has a surface facing away from the rotary actuator, which surface has an extension from its scraping element tangentially toward its rear end, wherein the scraper is constructed and arranged so that the distance between the surface facing away from the rotary actuator and the rotary actuator decreases toward the scraping element over at least a portion of the extension. On at least two scrapers, the surface facing away from the rotary actuator is opposite to the surface facing the rotary actuator. As is easily understood by a person skilled in the art, the distance defined between the surface facing away from the rotary actuator and the rotary actuator itself must inevitably be defined as passing through the scraper having the surface. In the context of defining the distance, "surface" should be understood as a mathematical or geometric surface. Similarly, in the case where the scraper device is arranged and operated in a roller crusher, it is beneficial that the scraper provides a surface that will cause the removed material to move toward the center of the roller.

[0034] According to one embodiment, the surface of the back-rotating actuator comprises a substantially flat surface. Therefore, for this embodiment, the distance of the variation described above can be further represented by the angle γ defined between the surface of the back-rotating actuator and the reference plane, wherein the angle γ is defined in the tangential plane of the scraper orthogonal to the reference plane. The angle γ can be 1° to 45°, or 1° to 40°, or 1° to 30°, or 5° to 45°, or 5° to 25°, or 5° to 20°, or 5° to 15°, or 8° to 12°, or 10°. Although preferably angled so that the distance between the surface of the back-rotating actuator and the rotary actuator is reduced toward the scraping surface on at least a portion of the extension, it is also conceivable to provide such a scraper having a surface of the back-rotating actuator, the scraper being arranged so that the distance between the surface of the back-rotating actuator and the rotary actuator is increased toward the scraping surface on at least a portion of the extension. As will be readily appreciated by those skilled in the art, for substantially flat surfaces, this will be defined using the negative angle γ using the above definition. For such embodiments, the angle γ may therefore be -1° to -45°, or -1° to -40°, or -1° to -30°, or -5° to -25°, or -5° to -20°, or -5° to -15°, or -8° to -12°, or -10°.

[0035] According to one embodiment, the at least two scrapers are arranged to form an axial protrusion on one or both sides of the rotatable multi-head scraper unit. In other words, the at least two scrapers are arranged so that they extend axially beyond one or both axial ends of the remaining part of the rotatable multi-head scraper unit. Therefore, when the scraper device is arranged in a roller crusher and the at least two scrapers have an axial protrusion toward the flange, the distance between the active scraper and the flange is narrower than the distance between the remaining part of the rotatable multi-head scraper unit and the flange. One advantage of this is that when the scraper device is arranged and operated in a roller crusher, once the removed material flows along the surface of the scraper facing the flange, it is easy to be removed through the wider gap between the inner surface of the flange and the remaining part of the rotatable multi-head scraper unit and flow to the center of the roller, rather than being squeezed and compacted between the rotatable multi-head scraper unit and the inner surface of the flange.

[0036] According to one embodiment, the axial protrusion has an axial extension in the range of up to 75 mm, or 5 to 50 mm, or 10 to 40 mm. Although the ranges disclosed above are currently preferred, it is conceivable that the axial extension may also be greater than 75 mm. The axial extension may depend on the roller crusher, the operating conditions and the material to be crushed, among other things. Therefore, the axial extension must be selected based on parameters such as, but not limited to, the crushing gap, the size of the crushing rollers and the size of the built-up material to be removed. Larger material build-ups may require larger axial extensions.

[0037] According to one embodiment, each of the at least two scrapers extends in a reference plane along a scraper axis towards the scraper element, and wherein the scraper axis forms a first acute angle along a reference rotation direction with a radial axis of the rotatable multi-head scraper unit, which intersects the scraper element. An advantage of this is that the forces acting on the scraper element during operation will become substantially aligned with the scraper element axis and are more likely to be absorbed in the direction of the scraper element axis, which is well supported and attached by the rotatable multi-head scraper unit.

[0038] According to one embodiment, each scraping surface of the at least two scrapers extends in a plane having a normal which forms an acute angle with the scraper axis along the reference direction. Again, an advantage of this is that during operation, the forces acting on the scraper element become substantially more aligned with the scraper axis and are more likely to be absorbed in the direction of the scraper axis, which is well supported and attached by the rotatable multi-head unit.

[0039] According to one embodiment, at least two scrapers each have a surface facing away from the rotary actuator and a surface facing the rotary actuator, and at least one of the surface facing away from the rotary actuator and the surface facing the rotary actuator comprises a ceramic insert. Arranging ceramic inserts on these surfaces will extend the wear life of the at least two scrapers.

[0040] According to one embodiment, the rotatable multi-head scraper unit has an annular joint portion, and each of the at least two scrapers is releasably arranged to the annular joint portion. The term "annular joint portion" should be interpreted as an annular portion of a structure, which may consist of one element or an assembly of multiple elements, which forms the periphery on which at least two scrapers are releasably arranged. The annular joint portion can, for example, be a peripheral annular portion of a rotatable disc. Providing releasable scrapers can be advantageous because this allows selective replacement of individual scrapers. Thus, for example, if one scraper is damaged, the remaining scrapers can remain stationary and only the damaged element can be replaced.

[0041] According to one embodiment, the rotatable multi-head scraper unit further comprises a main support structure and at least two scraper support structures, wherein the at least two scraper support structures are releasably arranged relative to the main support structure and are shaped as a circular ring sector (circular ring section) that together form a circular ring, and the circular ring has an annular engagement portion. In principle, the rotatable multi-head scraper unit may include any number of scraper support structures. Therefore, it is also conceivable to provide a single scraper support structure. However, the advantage of providing at least two scraper support structures is that it allows installation on the main support structure, which is rotatably arranged on the through-axis. At least two scraper support structures may have the same size. Therefore, for an embodiment with two scraper support structures, each scraper support structure may constitute a 180-degree circular ring sector. Alternatively, for an embodiment with three scraper support structures, each scraper support structure may constitute a 120-degree circular ring sector. Alternatively, for an embodiment with four scraper support structures, each scraper support structure may constitute a 90-degree circular ring sector. It is also conceivable that two or more scraper support structures have different sizes. However, each embodiment has one thing in common: the at least two scraper support structures will form a ring together, and the ring will have an annular joint portion. These exemplary embodiments may be advantageous because they provide modularity of the design, thus facilitating easier and faster maintenance. By providing at least two scraper support structures, a complete module including several scrapers may be removed from a scraper device in a single operation. This may also increase speed and reliability when replacing scrapers on a scraper device, since each scraper may be replaced by replacing only the at least two scraper support structures.

[0042] According to one embodiment, each of the at least two scrapers is releasably arranged in the annular joint portion by a geometric locking engagement. This can be advantageous because it allows the structure to be impact-resistant. During operation, the scraper in operation will repeatedly hit the accumulated material on the flanged roller, which will result in a torsional load on the connection area between the scraper and the annular joint portion. By providing a locking engagement, this load can be at least partially absorbed by the structure itself, thereby reducing the load on the fasteners (such as bolts, screws and nuts) that are typically used to provide the releasable arrangement of the scraper to the annular joint portion. The geometric locking engagement can be implemented in different ways, which will be described in detail below.

[0043] According to one embodiment, the geometric locking engagement is at least partially defined by a protruding structure of the scraper blade being inserted into an associated recess of the annular engagement portion, wherein the protruding structure and the associated recess have complementary shapes.

[0044] This is considered to be a preferred way to provide a locking engagement. This is achieved by providing complementary shapes on the at least two scrapers and the annular engagement portion, respectively. This complementary shape can be a protrusion, which, when inserted into the recess, is locked to the recess only by the shape of the protrusion. A simple example can be a rod extending into a hole. A conceivable way to provide a locking engagement can be to provide a plurality of radially inwardly directed holes on the periphery of the annular engagement portion and allow the scrapers to extend into these holes. They can then be fixed to the annular engagement portion by bolting. As those skilled in the art will readily appreciate, bolts will not absorb most of the torsional loads, instead, these loads will be absorbed by the hole-protrusion arrangement with complementary shapes.

[0045] According to one embodiment, the associated recess of the annular engagement portion is defined on its side surface. This can be advantageous because it allows easier replacement. Providing the recess on the side surface of the annular engagement portion can reduce the risk of jamming between the annular engagement portion and the scraper due to dust and contaminants entering the recess.

[0046] According to one embodiment, each of the at least two scrapers comprises a scraper body, and wherein the protruding structure forms part of the scraper body. This can be advantageous because it allows a more modular system. The dedicated scraper (referred to herein as the "active scraper") allows for individual replacement without having to replace the rest of the scraper (i.e., the scraper body). However, during replacement, it is conceivable that it is easier to replace the entire scraper including the active scraper and the scraper support structure with a new scraper. However, once the scraper is removed, it can be taken to a workshop or other dedicated facility, where the worn active scraper can be replaced with a new scraper, mounted on the scraper body. Thus, the same scraper body can be used multiple times.

[0047] According to one embodiment, the scraper device further comprises a wear-resistant cover constructed and arranged to protect at least a portion of the rotatable multi-head scraper unit. Wear-resistant covers can be advantageous because they allow the rotatable multi-head unit to be protected from the harsh environment in which it is intended to work. Typically during crusher operation, in particular during the removal of accumulated material from the flanged rollers, there will be a high density of high-speed stones, sand and dust constantly impinging on the surface of the rotatable multi-head scraper unit, thus increasing the risk of wear of the parts, as well as damage due to penetration into cavities and gaps, which may also increase the complexity of maintenance and replacement.

[0048] According to an embodiment of the scraper device, the rotatable multi-head scraper unit is releasably arranged in the scraper device to allow replacement of the rotatable multi-head scraper unit. For example, such a replacement of the rotatable multi-head scraper unit can be performed when at least two scrapers are completely worn.

[0049] According to one embodiment of the scraper device, the rotatable multi-head scraper unit comprises at least three, or at least four, or at least five scrapers, which are arranged tangentially around the rotatable multi-head scraper unit at corresponding radial distances from the axis of rotation. As is easily understood by a person skilled in the art, having a greater number of scrapers on the rotatable multi-head scraper unit will extend the operating time of the scraper device before the rotatable multi-head scraper unit has to be replaced after all scrapers have been worn. The maximum number of scrapers arranged on the rotatable multi-head scraper unit depends on the radial extension of the rotatable multi-head scraper unit. Therefore, the larger the radial extension of the rotatable multi-head scraper, the greater the number of scrapers that can be arranged on the rotatable multi-head scraper unit. Its size is designed according to the available space of the roller crusher and the flanged end of the roller to be used.

[0050] According to an embodiment of the scraper arrangement, the first scraper in the train and the last scraper in the train are positioned such that they are separated by an angle of at least 120 degrees upstream of the first scraper in the train.

[0051] The term "first scraper in the queue" refers to the scraper that will be used first in operation among the at least two scrapers arranged on the rotatable multi-headed scraper unit when the scraper device has been installed in the roller crusher or when a new rotatable multi-headed scraper unit has been arranged on the scraper device. It should be understood that the term is not necessarily used to distinguish a specific scraper among the at least two scrapers on the rotatable multi-headed scraper unit. The first scraper in the queue can be any one of the at least two scrapers. Alternatively, the first scraper in the queue will be the scraper that first performs the scraping operation. For some embodiments of the rotatable multi-headed scraper unit, the at least two scrapers can be positioned so that one scraper will be the natural first scraper in the queue. This applies to such a rotatable multi-headed scraper unit in which the at least two scrapers are unevenly distributed on the rotatable multi-headed scraper unit.

[0052] The term "last scraper in the queue" refers to the scraper that will be used last in operation among the at least two scrapers arranged on the rotatable multi-head scraper unit when the scraper device has been installed in the roll crusher or when a new rotatable multi-head scraper unit has been arranged on the scraper device. Thus, when two scrapers are arranged on the rotatable multi-head scraper unit, the second scraper in the queue is the last scraper in the queue, or when three scrapers are arranged on the rotatable multi-head scraper unit, the third scraper in the queue is the last scraper in the queue, or when four scrapers are arranged on the rotatable multi-head scraper unit, the fourth scraper in the queue is the last scraper in the queue, and so on.

[0053] The phrase "upstream of the first scraper in the queue" refers to the area in front of the scraping surface of the first scraper in the queue which will encounter any accumulated material as the rollers of the roller crusher rotate during operation of the roller crusher. Thus, the "stream" in this case will correspond to the accumulated material at the flange which typically extends annularly around the roller surface of the roller at the flange and thus often continuously impinges on the scraper surface as a "stream" of material during crushing operations. However, as will be readily appreciated by those skilled in the art, "upstream" is used herein only to define a direction and thus the expression should not be interpreted as limiting the material distribution at the flange in any particular way.

[0054] An advantage of this arrangement is that any accumulated material scraped off by the first scraper in the queue has little or no impact on the back surface of the last scraper in the queue. This can be beneficial because it reduces wear on the scraper and thus extends the life of the scraper assembly.

[0055] According to one embodiment of the scraper arrangement, a wear protection lining is arranged on the back surface of the last scraper in the train.

[0056] An advantage of this arrangement is that if any accumulated material scraped off by the first scraper in the queue has an impact on the back surface of the last scraper in the queue, the wear protection lining will protect the last scraper in the queue from damage before it is used during operation.

[0057] According to one embodiment of the scraper arrangement, the first scraper in the train and the last scraper in the train are positioned such that they are separated by an angle of at least 140 degrees upstream of the first scraper in the train.

[0058] According to one embodiment of the scraper arrangement, the first scraper in the train and the last scraper in the train are positioned such that they are separated by an angle of at least 160 degrees upstream of the first scraper in the train.

[0059] According to one embodiment of the scraper arrangement, the first scraper in the train and the last scraper in the train are positioned such that they are separated by an angle of at least 180 degrees upstream of the first scraper in the train.

[0060] An advantage of this arrangement is that the scraper arrangement can be arranged relative to the roller crusher so that the accumulated material scraped off by the first scraper in the queue has no or little impact on the back surface of the last scraper in the queue, because the scraped accumulated material will pass through the rotatable multi-head scraper unit in an area where neither scraper is arranged tangentially at a radial distance from the rotation axis of the rotatable multi-head scraper unit. In addition, when the first scraper in the queue is worn, the second scraper in the queue will be rotated into position for operation. During the operation of the second scraper in the queue, the scraped accumulated material will have an impact on the back surface of the first scraper in the queue, but since the first scraper in the queue is already worn and needs to be replaced anyway, the wear of its back surface is irrelevant when the second scraper in the queue is in operation. In addition, when the second scraper in the queue is worn, a possible third scraper in the queue will be rotated into position for operation. In the operation of the third scraper in the possible row, the scraped accumulated material will have an impact on the back surface of the second scraper in the row, but since it is already worn, it needs to be replaced anyway, so when the third scraper in the possible row is in operation, the wear of its back surface is not a big deal. If four or five scrapers are arranged as at least two scrapers on the rotatable multi-head scraper unit, the same is true for the fourth scraper in the possible row or the fifth scraper in the possible row.

[0061] Typically, the at least two scrapers are arranged at the same radial distance from the axis of rotation of the rotatable multi-head scraper unit. In other words, the respective radial distances may be equal to one another. However, it is also conceivable that at least one of the at least two scrapers is arranged at a radial distance that is different from the radial distance at which the other of the at least two scrapers is arranged. It is also conceivable that the at least two scrapers are arranged at radial distances that are different from one another from the axis of rotation of the rotatable multi-head scraper unit.

[0062] The purpose of providing different distances may be to allow the degree of scraping to be conveniently selected. For example, there may be situations where a higher degree of tolerance for accumulated material is present than in other situations. This may occur, for example, when a roller crusher is operated with a relatively large crushing gap. In this case, the rotatable multi-head scraper unit may be rotated so that a scraper positioned close to the roller is interchanged with another scraper positioned away from the roller.

[0063] According to one embodiment, the scraper device may further include a shaft member having a first end and a second end and being rotatably arranged, wherein the rotatable multi-head scraper unit is attached at the first end of the shaft member, and wherein the rotary actuator is arranged at the second end of the shaft member.

[0064] This can be advantageous because it allows the rotatable multiple scraper unit to be controlled from a distance. This is particularly advantageous on roller crushers where the rotatable multiple scraper unit must be arranged at a flange area of ​​the roller, which area is not always easily accessible from the outside. The shaft member can, for example, be arranged to protrude through a wall or structure of the roller crusher, so that the rotatable multiple scraper unit is arranged on a first side of the wall / structure and the rotary actuator is arranged on the other side of the wall / structure.

[0065] The rotatable multi-head scraper unit can be releasably attached to the shaft member. This can be achieved in many optional ways. For example, the rotatable multi-head scraper unit can be releasably attached to the shaft member by a releasable fastening device (such as a flange connector or a bushing). The bushing can be, for example, a tapered bushing, an XT bushing or a QD bushing.

[0066] According to one embodiment, the scraper device further comprises a support device, which is arranged to at least partially surround the shaft member and is also arranged to be connected to the frame of the roller crusher. This means that the rotatable multi-head scraper unit can be supported by the shaft member, which in turn is supported by the support device. This can be advantageous because it allows replacing the rotatable multi-head scraper unit without having to interact with the support device.

[0067] As will be readily appreciated by those skilled in the art, the support means need not necessarily completely surround the shaft member.As a non-limiting example only, the shaft member may be supported by two concave elements engaging the shaft member from opposite directions.

[0068] According to one embodiment, a first braking device of the at least one braking device is supported by the supporting device, and wherein the first braking device comprises a friction element configured to selectively engage with the shaft member or an engagement element attached thereto, thereby preventing and / or limiting rotation of the rotatable multi-head scraper unit.

[0069] The friction element may be elastic. The friction element may be made of rubber or polyurethane. Alternatively, the friction element may be attached to another element, which is elastic. The further element may be made of rubber or polyurethane. The use of an elastic element may be advantageous because it allows a more uniform application of pressure on the shaft member or engagement element in response to the elastic element being subjected to an external force.

[0070] According to one embodiment, the friction element is elastic or attached to an elastic support element, and wherein the first braking device further comprises a support structure constructed and arranged to at least partially surround the friction element or the support element.

[0071] This can be advantageous because it allows the engagement with the shaft member or engagement element to be initiated by exposing the elastic friction element or the elastic support element to a compressive force having an arbitrary direction relative to the shaft. This technical effect occurs because the elastic friction element, due to its elastic properties, will apply pressure to the shaft member or engagement element in response to any attempt to compress the elastic friction element or the elastic support element within the support structure. Therefore, there is no need to provide a compressive force on the elastic element in a direction substantially parallel to the direction in which the elastic element engages with the shaft member or engagement element. As long as the elastic element is compressed, it will expand in a direction towards the shaft member or engagement element, thereby applying pressure to it.

[0072] According to one embodiment, the at least one braking device comprises a locking device configured to selectively lock the rotation of the rotatable multi-head scraper unit during operation of one of the at least two scrapers. The locking device is releasable and may comprise: a first structure having a first set of through holes and a second structure having a second set of through holes, wherein the first structure is connected to the rotatable multi-head scraper unit and the second structure is configured to be connected to a frame of the roller crusher; and one or more bolts for rotationally locking the first and second structures relative to each other by inserting the one or more bolts through overlapping associated through holes in the first set of through holes and the second set of through holes.

[0073] According to one embodiment, the rotary actuator comprises a gearbox.

[0074] The term "gearbox" refers to a part of a transmission system that includes a gear train including at least one driving gear that is provided with torque and a driven gear that is mechanically connected to the driving gear and transmits torque from the gearbox. A simple gearbox may consist of only a driving gear and a driven gear. In such a gearbox, the driving gear meshes directly with the driven gear. The gearbox may optionally include one or more additional intermediate gears, also called idler gears, which interconnect the driving gear and the driven gear so as to provide a mechanical link between the driving gear and the driven gear. It is conceivable that any type of gear may be used in a gearbox according to the present disclosure. The gears include spur gears, bevel gears, worm gears, etc.

[0075] Providing a gearbox can be advantageous because it allows providing a suitable gear ratio to selectively rotate the rotatable multi-head scraper unit. It is conceivable that many embodiments of the scraper device disclosed herein will require providing a considerable torque to rotate the rotatable multi-head scraper unit. By providing a gearbox, the rotatable multi-head scraper unit can be manipulated by hand, for example by means of a steering wheel or crank. Another advantage of the gearbox is that it allows torque to be provided in a direction that is not parallel to the axis of rotation of the rotatable multi-head scraper unit. This can be achieved by a gearbox including gearing such as a worm drive, hypoid gears, cross helical gears, etc.

[0076] According to one embodiment, the gearbox is configured to act as a second braking device of the at least one braking device.

[0077] As previously described with reference to the first embodiment, the braking device of the present disclosure need not be limited to what is conventionally referred to as a brake. Instead, the term "braking device" should be interpreted as encompassing all devices configured to prevent and / or limit rotation. As will be readily appreciated by those skilled in the art, a gearbox will always have a certain degree of frictional resistance, which will provide a certain degree of braking force to the mechanical system engaged with the gearbox. The braking force will increase as the friction in the gear train increases.

[0078] According to one embodiment, the gearbox comprises a gear train having a transmission ratio greater than 1. Alternatively, the gear train may have a transmission ratio greater than 10, or greater than 20, or greater than 40.

[0079] The gear ratio of a gear train is defined as the ratio of the number of revolutions of the driving gear to the number of revolutions of the driven gear. This means that a gear ratio greater than 1 will allow a higher number of revolutions generated by applying a lower torque to the driving gear to be converted into a lower number of revolutions with a higher torque on the driven gear.

[0080] A gearbox having a gear train with a transmission ratio greater than 1 can be beneficial for several reasons. First, as previously mentioned, it provides a method of converting a low torque rotation into a high torque rotation. This can be advantageous because it allows the rotatable multi-head scraper unit to be manipulated by hand, for example, with the aid of a steering wheel or crank. In addition, the transmission ratio will also affect the braking force that the gearbox can provide to the rotatable multi-head scraper unit. Specifically, the braking force will increase as the transmission ratio of the gear train increases.

[0081] According to one embodiment, the third braking device of the at least one braking device is a ratchet device.

[0082] The ratchet device is configured to prevent rotational movement in one rotational direction and allow rotational movement in the opposite rotational direction. The ratchet device may include a ratchet in the form of a gear having uniform but asymmetrical teeth, each tooth having a moderate slope on one edge and a steeper slope on the other edge. The ratchet device may also include a pivoting, usually spring-loaded finger (sometimes called a pawl) that engages the teeth. When the teeth move in an unrestricted (i.e., forward) direction, the pawl easily slides up and over the gently inclined edge of the teeth, and the spring forces the pawl into the recess between the teeth as the pawl passes the tip of each tooth. However, when the teeth move in the opposite (rearward) direction, the pawl will get stuck on the steeply inclined edge of the first tooth it encounters, thereby locking it on the tooth and preventing any further movement in that direction.

[0083] The ratchet device can be advantageous because it is used to limit movement to only one rotational direction, which allows better control of the scraper device. The ratchet device can be configured to prevent rotation in a rotational direction opposite to the rotational direction of the roller having the flange. This can be advantageous because it can prevent one of the at least two scrapers from being forced backwards in response to an impact from the accumulated material at the flange. However, it is conceivable that a release mechanism can be used in the event that the impact force exceeds the maximum permissible impact force. Therefore, the ratchet device can include a torque limiter configured to disable the ratchet mechanism, thereby allowing rotational movement along both rotational directions.

[0084] According to one embodiment, the scraper device includes two rotatable multi-head scraper units, which are arranged at opposite ends of a roller, and the roller has two flanges attached to the opposite ends, each rotatable multi-head scraper unit has at least two scrapers, which are arranged tangentially around the rotatable multi-head scraper unit at corresponding radial distances from the rotation axis of the rotatable multi-head scraper unit, and wherein the rotary actuator is arranged to selectively cause the two rotatable multi-head scraper units to rotate together.

[0085] This may be advantageous as it would allow dual scrapers to be controlled using a single actuator mechanism.

[0086] According to one embodiment, the squeegee device further comprises a drive unit arranged to provide kinetic energy to the rotary actuator for selective rotation of the rotatable multi-head squeegee unit.

[0087] This can be advantageous as it allows the scraper replacement to be controlled remotely.

[0088] According to one embodiment, the scraper arrangement has a rotation indexing capability for enabling the rotatable multi-head scraper unit to selectively rotate between predetermined angular positions.

[0089] The rotational indexing capability may be advantageous because it facilitates the selection of a suitable operating position. For example, the rotational indexing capability may be beneficial when replacing a scraper in operation, which is achieved by rotating the rotatable multi-head scraper unit so as to exchange one of the at least two scrapers with the other of the at least two scrapers at the flanged end of the roller. The rotational indexing capability may also be beneficial when adjusting the position of the scraper in operation without replacing the scraper. The multi-head scraper unit may be rotated so that the scraper in operation moves from a first operating position to a second operating position, which operating positions have different distances from the envelope surface. The rotational indexing capability may be used to define a plurality of predetermined operating positions for the scraper in operation, each operating position corresponding to an associated predetermined angular position of the rotatable multi-head scraper unit.

[0090] The rotary indexing capability may be achieved by an integrated motion system. Such an integrated motion system may typically include a motor and a mechanical power transmission device as well as an encoder, a sensor and a controller. Therefore, the scraper device may also include at least one sensor for determining the angular position of the rotatable multi-head scraper unit and / or the position of one or more of the at least one scraper. The scraper device may also include at least one drive unit for rotating the rotatable multi-head scraper unit. The scraper device may also include at least one control unit for rotating the rotatable multi-head scraper unit.

[0091] According to one embodiment, the periphery of the rotatable multi-head scraper unit, when viewed between a pair of adjacent scrapers of the two or more scrapers, has a radial extension which is at least 20 mm smaller than a minimum radial distance of the pair of adjacent scrapers.

[0092] In this context, the term "circumference of the rotatable multi-headed scraper unit" refers to the radial extension of the rotatable multi-headed scraper unit defined transversely to the axis of rotation.

[0093] Providing a perimeter that is at least 20 mm smaller than the minimum radial distance of the pair of adjacent scrapers can be advantageous because it allows the removed accumulated material to more easily leave the rotatable multi-head scraper unit. If the perimeter of the rotatable multi-head scraper unit is too close to the minimum radial distance of the pair of adjacent scrapers, as seen between a pair of adjacent scrapers of two or more scrapers, there is a risk that the removed accumulated material may get stuck between the perimeter and the envelope surface of the roller.

[0094] The minimum difference between the radial extension of the periphery of the rotatable multi-head scraper unit and the minimum radial distance of the pair of adjacent scrapers, as seen between the pair of adjacent scrapers, may vary with the roller diameter. The reason for this is that the crushing gap generally increases with the roller diameter, resulting in an excessive amount of thicker deposited material accumulating on the envelope surface of the roller at the end portion adjacent to the flange and / or on the flange. It is conceivable that the minimum difference defined above must exceed the thickness of the deposited material. Therefore, for a roller crusher with a large crushing roller, the difference defined above may have to be greater than 20 mm. The radial extension may be in the range of 20 mm to 150 mm less than the minimum radial distance of the pair of adjacent scrapers.

[0095] According to a second embodiment of the present disclosure, this object and other objects are fully or at least partially achieved by a roller crusher having two substantially parallel rollers arranged to rotate in opposite directions and separated by a gap, each roller having two ends, and the roller crusher comprising: a flange attached to one of the two ends of one of the rollers, the flange extending in the radial direction of the roller, and the flange having an extension (E1) that exceeds (past, passes) the envelope surface of the roller. The roller crusher also includes a scraper device as disclosed in the first embodiment of the present disclosure, wherein the rotatable multi-head scraper unit is arranged so that one of the at least two scrapers is selectively positioned at the end of the roller having the flange by a rotary actuator, and is prevented and / or restricted from moving relative to the roller by at least one braking device, thereby at least partially allowing the removal of materials accumulated on the envelope surface and / or on the flange at the end portion of the roller adjacent to the flange.

[0096] According to one embodiment, the scraper device is arranged such that the active scraper is arranged at a distance from the outer surface at the end of the roller and / or from the flange.

[0097] The roller crusher can be operated for an economically acceptable period of time at this position of the functioning scraper before the scraper has worn to the point where the distance between the scraper and the outer surface of the roller will approach the minimum gap between the rollers for crushing and the scraper must be repositioned or replaced. The minimum gap between the rollers is set by a movement blocking device that physically prevents the rollers from moving closer to each other than the distance specified by the predetermined minimum gap.

[0098] The distance between the active scraper and the roller surface and / or the flange can alternatively be defined using a minimum roller distance and a minimum flange distance, respectively. The minimum roller distance is defined as the minimum distance between the active scraper and the roller outer surface. Similarly, the minimum flange distance is defined as the minimum distance between the active scraper and the flange inner surface.

[0099] According to an embodiment of the second aspect, the roller crusher comprises two flanges attached to opposite ends of one of the rollers, and wherein a scraper device according to the first aspect is arranged at each end of the roller having a flange.

[0100] According to an embodiment of the second scheme, the roller crusher includes two flanges attached to opposite ends of one of the rollers and a scraper device, the scraper device including two rotatable multi-head scraper units, each rotatable multi-head scraper unit having at least two scrapers, the scrapers being arranged tangentially around the rotatable multi-head scraper unit at corresponding radial distances from the rotation axis of the rotatable multi-head scraper unit, and wherein the rotary actuator is arranged to selectively rotate the two rotatable multi-head scraper units together, and wherein the scraper device is arranged so that the two rotatable multi-head scraper units are arranged at opposite ends of the roller, and the roller has two flanges attached to the opposite ends.

[0101] According to an embodiment of the second aspect, the roller crusher further comprises a sensor system for monitoring the status of the scraper arrangement, and a controller operatively connected to the sensor system and to the drive unit.

[0102] This is advantageous because it allows to automatically determine when a worn scraper needs to be replaced. It is conceivable that such a replacement operation is possible during the operation of the roller crusher, thus eliminating the need to shut down the roller crusher. In addition, the sensor system can allow an improved prediction of when the roller crusher must be shut down to replace a completely worn rotatable multi-head scraper unit. For example, the sensor system can be configured to determine how many of the at least two scrapers are still available for scraping.

[0103] The second solution generally has the same advantages as the first solution. In addition, the embodiments disclosed for the first solution are also applicable to the second solution.

[0104] According to the third embodiment of the present disclosure, this object and other objects are fully or at least partially achieved by an operating method of a roller crusher for grinding granular materials, wherein the roller crusher has two substantially parallel rollers, which are arranged to rotate in opposite directions and are separated by a gap, each roller having two ends, and the roller crusher includes: a flange attached to one of the two opposite ends of one of the rollers, the flange extending in the radial direction of the roller, and the flange having an extension (E1) passing through the envelope surface of the roller, wherein the roller crusher also includes a scraper device as disclosed in the first embodiment of the present disclosure, wherein the rotatable multi-head scraper unit is arranged so that one of the at least two scrapers is selectively positioned at the end of the roller having the flange by a rotary actuator, and is prevented and / or restricted from moving relative to the roller by at least one braking device; wherein the method includes at least the following steps: by means of one of the at least two scrapers, at least partially removing material accumulated on the envelope surface and / or on the flange at the end portion of the roller adjacent to the flange.

[0105] According to an embodiment of the third aspect, the method further comprises the step of rotating the rotatable multi-head scraper unit so that one of the at least two scrapers is exchanged with another one of the at least two scrapers at the end of the roller having the flange.

[0106] According to an embodiment of the third scheme, the method also includes the following steps: enabling the rotatable multi-head scraper unit to rotate so that one of the at least two scrapers moves from a first operating position to a second operating position, wherein the distance between one of the at least two scrapers and the envelope surface defined in an unworn state of one of the at least two scrapers is larger in the first operating position than in the second operating position.

[0107] During the scraping operation, the scraper blade is subject to wear. Therefore, the radial extension of the scraper blade (i.e. the radial distance from the axis of rotation of the rotatable multi-head scraper unit) will gradually decrease during the life of the scraper blade. This will cause the accumulated material at the flange to gradually thicken over time. In other words, even if the scraper blade in operation always performs effective scraping of the envelope surface, the scraping operation will not be consistent in time. By adjusting the angular position of the rotatable multi-head scraper unit, the scraper blade in operation can be moved to a position closer to the envelope surface, thereby compensating for the wear effects on the radial extension of the scraper blade.

[0108] The scraper device may preferably have a rotation indexing capability for selectively rotating the rotatable multi-head scraper unit between predetermined angular positions. The rotation indexing capability may be advantageous because it facilitates the selection of a suitable operating position. In particular, the rotatable multi-head scraper unit may be rotated so that the scraper in operation moves from a first operating position to a second operating position, the operating positions having different distances from the envelope surface. The rotation indexing capability may be used to define a plurality of predetermined operating positions of the scraper in operation, each operating position corresponding to an associated predetermined angular position of the rotatable multi-head scraper unit.

[0109] According to an embodiment of the third aspect, the squeegee device further comprises a drive unit arranged to provide kinetic energy to the rotary actuator for selective rotation of the rotatable multi-head squeegee unit, and wherein the method further comprises rotating the rotatable multi-head squeegee unit by means of the drive unit.

[0110] This can be advantageous as it eliminates the need to manually change the scraper at the roll crusher. In addition to the benefit of reduced manual labour, it allows the scraper change to be initiated from a distance.

[0111] According to an embodiment of the third scheme, the roller crusher also includes a sensor system for monitoring the status of the scraper device; and a controller operably connected to the sensor system and connected to the drive unit, wherein the method also includes the control unit controlling the rotation of the rotatable multi-head scraper unit based on output data from the sensor system.

[0112] This can be advantageous because it allows automatically determining when a worn scraper needs to be replaced, or when one of the at least two scrapers needs to be moved from a first operating position to a second operating position. It is envisaged that such a replacement or moving operation can be performed during operation of the roller crusher, thus eliminating the need to shut down the roller crusher. Furthermore, the sensor system can allow an improved prediction of when the roller crusher must be shut down to replace a completely worn rotatable multi-head scraper unit. For example, the sensor system can be configured to determine how many of the at least two scrapers are still available for scraping.

[0113] The third solution generally has the same advantages as the first and second solutions. In addition, the embodiments disclosed for the first solution are also applicable to the third solution.

[0114] Other objects, features and advantages of the present disclosure will appear from the following detailed disclosure, the attached claims and the drawings. Note that the present disclosure relates to all possible feature combinations.

[0115] In general, unless otherwise explicitly defined herein, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field. Unless otherwise explicitly stated, all references to "a / an / the [element, device, component, means, step, etc.]" should be publicly interpreted as referring to at least one instance of the element, device, component, means, step, etc. Unless explicitly stated otherwise, the steps of any method disclosed herein do not have to be performed in the exact order disclosed.

[0116] As used herein, "comprise", "comprises" and its variations are not intended to exclude other additives, components, integers or steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0117] The present disclosure will be described in more detail with reference to the accompanying drawings, which show examples of currently preferred embodiments of the present disclosure.

[0118] Figure 1 It is a perspective view of a roller crusher according to the prior art.

[0119] Figure 2A yes Figure 1 Schematic top view of the two rollers of a roller crusher.

[0120] Figure 2B is a schematic top view of two rollers of a prior art roller crusher according to an alternative embodiment.

[0121] Figure 3A is a top cross-sectional view of a section of a roller crusher according to the prior art.

[0122] Figure 3B is a side cross-sectional view of a section of a roll crusher according to an embodiment of the present disclosure.

[0123] Figure 3C is a top view of a portion of a roll crusher according to an embodiment of the present disclosure.

[0124] Figure 4 is a perspective view of a rotatable multi-head scraper unit according to an embodiment of the present disclosure.

[0125] Figure 5 is a perspective view of a rotatable multi-head scraper unit according to another embodiment of the present disclosure.

[0126] Figure 6 According to the embodiment of the present disclosure Figure 4 A cross-sectional side view of a rotatable multi-head scraper unit arranged at the lower end of a flanged roller.

[0127] Figure 7 According to the embodiment of the present disclosure Figure 5A cross-sectional side view of a rotatable multi-head scraper unit arranged at the upper end of a flanged roller.

[0128] Fig. 8A According to the embodiment of the present disclosure, Figure 4 A partially cutaway stereoscopic view of a scraper device capable of rotating a multi-head scraper unit.

[0129] Figure 8B yes Fig. 8A An exploded perspective view of the scraper device and the part of the rotatable multi-head scraper unit.

[0130] Fig.9A According to another embodiment of the present disclosure Fig. 8A A perspective view of a scraper device, but here instead of carrying Figure 5 The multi-scraper unit can be rotated.

[0131] Fig. 9B yes Fig.9A A partially cut-away front view of a scraper device and a rotatable multi-head scraper unit.

[0132] Fig.10 is a schematic side view of a portion of a roll crusher, a scraper assembly, and a sensor system for monitoring the condition of the scraper assembly according to an exemplary embodiment of the present disclosure.

[0133] Fig.11 is a schematic side view of a rotatable multi-head scraper unit arranged in two different operating positions relative to a roller according to an embodiment of the present disclosure.

[0134] Fig. 12A is a perspective view of a portion of a scraper device according to another embodiment of the present disclosure.

[0135] Fig. 12B yes Fig. 12A A stereoscopic view of a rotatable multi-head scraper unit of a scraper device.

[0136] Fig. 12C yes Fig. 12A A three-dimensional diagram of a scraper device in which the rotatable multi-head scraper unit is omitted.

[0137] Fig.13A yes Fig. 12A and Fig. 12B A stereoscopic view of a portion of a rotatable multi-head scraper unit.

[0138] Fig. 13B yes Fig.13A A side view of the portion of the rotatable multi-head scraper unit.

[0139] Fig. 13C yes Fig.13AA top view of the portion of the rotatable multi-head scraper unit.

[0140] Fig.14A is a perspective view of a portion of a rotatable multi-head scraper unit according to another embodiment of the present disclosure.

[0141] Fig. 14B yes Fig.14A A side view of the portion of the rotatable multi-head scraper unit.

[0142] Fig. 14C yes Fig.14A A top view of the portion of the rotatable multi-head scraper unit.

[0143] Fig.14D is formed Fig.14A Exploded view of a scraper that is part of a rotatable multi-head scraper unit.

[0144] Fig.14E is formed Fig.14A An exploded view of a scraper body and a scraper support structure that is part of a rotatable multi-head scraper unit.

[0145] Fig.15A is a perspective view of a portion of a rotatable multi-head scraper unit according to another embodiment of the present disclosure.

[0146] Fig. 15B yes Fig.15A A side view of the portion of the rotatable multi-head scraper unit.

[0147] Fig. 15C yes Fig.15A A top view of the portion of the rotatable multi-head scraper unit.

[0148] Fig.16A is a perspective view of a portion of a rotatable multi-head scraper unit according to another embodiment of the present disclosure.

[0149] Fig. 16B yes Fig.16A A side view of the portion of the rotatable multi-head scraper unit.

[0150] Fig. 16C yes Fig.16A A top view of the portion of the rotatable multi-head scraper unit.

[0151] Fig.17A is a perspective view of a portion of a rotatable multi-head scraper unit according to another embodiment of the present disclosure.

[0152] Fig. 17B yes Fig.17A A side view of the portion of the rotatable multi-head scraper unit.

[0153] Fig. 17C yes Fig.17A A top view of the portion of the rotatable multi-head scraper unit.

[0154] Fig.18A is a side view of a rotatable multi-head scraper unit according to another embodiment of the present disclosure.

[0155] Fig.18B yes Fig.18A A three-dimensional view of a rotatable multi-head scraper unit.

[0156] Fig. 18C is formed Fig.18A and Fig.18B A stereoscopic view of a scraper that is part of a rotatable multi-head scraper unit.

[0157] Fig.19 is a perspective view of two scraper devices according to another exemplary embodiment of the present disclosure, the two scraper devices being located on opposite sides of a frame of a roll crusher.

[0158] Fig. 20 yes Fig.19 An enlarged stereoscopic view of one of the scraper devices.

[0159] Fig.21 is a perspective view of a wear cover for a rotatable multi-head scraper unit according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0160] The present disclosure will be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the present disclosure are shown. However, the present disclosure may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for purposes of thoroughness and completeness and to fully convey the scope of the present disclosure to those skilled in the art. The same reference numerals indicate the same elements throughout.

[0161] As discussed in the background section of this disclosure, flanges (such as Figure 2A As shown and discussed further below), a flange (such as Figure 2A and further discussed below), or by arranging a flange on each grinding roller (such as Figure 2BThe invention relates to a roller crusher which is a type of roller crusher which is used to crush the rollers. The roller crusher ...

[0162] Reference Figures 4 to 21 This is achieved completely or at least partially by a scraper device 200, 200', 400, 500, 1100, 1100' and a roller crusher 1 comprising such a scraper device 200, 200', 400, 500, 1100, 1100', which includes a rotatable multi-head scraper unit 210, 210', 510' 0, 1010, 1110, which has at least two scrapers 100, 501, 601, 701, 801, 901, 1001, 1101, which are arranged tangentially around the rotatable multi-head scraper unit 210, 210', 510, 1010, 1110 at a corresponding radial distance T from the rotation axis A of the rotatable multi-head scraper unit 210, 210', 510, 1010, 1110. The scraper device 200, 200', 400, 500, 1100, 1100' also includes a rotary actuator 202, 580 and at least one braking device B1, B2, B3, 570, the rotary actuator being arranged to enable the rotatable multi-head scraper unit 210, 210', 510, 1010, 1110 to selectively rotate to allow one of the at least two scrapers 100, 501, 601, 701, 801, 901, 1001, 1101 to be operatively used at each time, and the braking device being configured to prevent and / or limit the rotation of the rotatable multi-head scraper unit 210, 210', 510, 1010, 1110 during operation of one of the at least two scrapers 100, 501, 601, 701, 801, 901, 1001, 1101.

[0163] The scraper devices 200, 200', 400, 500, 1100, 1100' disclosed herein provide many advantages, such as enabling a compact scraper arrangement, reducing maintenance time for replacing worn scrapers, allowing an easier replacement procedure once the scraper needs to be replaced, allowing a fully automated scraper replacement procedure, and allowing adjustment of the distance between the scraper performing the scraping operation (referred to herein as the "scraper in operation") and the envelope surface of the roller by adjusting the angular position of the rotatable multi-head scraper unit.

[0164] Figure 1A roller crusher 1 according to the prior art is shown. Such a roller crusher 1 comprises a frame 2, wherein a first, fixed crushing roller 3 is arranged in bearings 5, 5'. The bearing housings 35, 35' of these bearings 5, 5' are fixedly attached to the frame 2 and are therefore immovable. The second crushing roller 4 is arranged in bearings 6, 6' in the frame 2, which are arranged in the frame 2 in a slidably movable manner. The bearings 6, 6' can be moved in the frame 2 in a longitudinal direction perpendicular to the first crushing roller 3 and the second crushing roller 4. Typically, guide structures 7, 7' are arranged in the frame on a first side 50 and a second side 50' along the upper and lower longitudinal frame elements 12, 12', 13, 13' of the roller crusher 1. The bearings 6, 6' are arranged in movable bearing housings 8, 8', which can slide along the guide structures 7, 7'. Furthermore, a plurality of hydraulic cylinders 9, 9' are arranged between the movable bearing blocks 8, 8' and first and second end supports 11, 11', which are arranged at or near the first end 51 of the roller crusher 1. These end supports 11, 11' are attached to upper and lower longitudinal frame elements 12, 12', 13, 13' and also serve as support for the forces generated at the hydraulic cylinders 9, 9' when the hydraulic cylinders 9, 9' adjust the gap width and react to the forces generated at the grinding rollers 3, 4 due to the feeding of material to the roller crusher 1.

[0165] This roller crusher works according to a technique called inter-particle crushing. The crushing rollers 3, 4 rotate in opposite directions to each other. Figure 1 The gap between the crushing rollers 3 and 4 is adjusted by the interaction of the feed load and the hydraulic system that affects the position of the second crushing roller 4. Figure 1 and the rollers 3 and 4 are shown in a top view. Figure 2A As shown, one of the grinding rollers 3 further comprises flanges 36, 36' arranged at two opposite ends of the grinding roller 3, wherein each flange 36, 36' has an extension E1 exceeding the envelope surface 37 of the roller body of the roller 3 (see Figure 3A ) and is positioned axially outside the roller body of the opposite grinding roller 4.

[0166] Another prior art roller crusher is disclosed in, for example, WO 2013 / 156968, wherein each grinding roller having a bearing is arranged in interconnected arched frame sections, wherein each interconnected arched frame section is pivotably connected to a base frame. The subject matter disclosed in the present disclosure is equally applicable to such prior art roller crusher arrangements.

[0167] Likewise Figure 3AAs shown, each flange 36 is arranged at one end of the roller 3 so that the inner surface 39 of the flange 36 is located at a distance F from one end of the opposite roller 4. The distance F is necessary to avoid contact between the flange 36 and the roller 4, which may cause material damage. At the same time, the distance F should not be too large, because this would increase the risk of the material leaving the roller crusher through the gap formed thereby. The distance F can be achieved by mounting the flange 36 on the roller 3 via the spacer 15, as shown in FIG. Figure 3A The purpose of the flanges 36, 36' is to prevent the material from flowing out of one end of the gap, thereby forcing all the material entering the roller crusher to be crushed through the crushing gap. Figure 2B An alternative embodiment of a roller crusher with flanges is shown. The only difference between the two embodiments is that Figure 2B The roller crusher in the embodiment has a flange 36 arranged on the second grinding roller 4' (rather than the first grinding roller 3'), which means that each grinding roller 3', 4' has a flange 36, 36'. As will be readily appreciated by those skilled in the art, the technical effect of preventing the material from leaving the roller crusher 1, 1' at both ends of the gap will be equally well achieved for both disclosed embodiments. Importantly, the disclosed inventive concept is equally applicable to both embodiments.

[0168] As mentioned above, the gap between the rollers 3, 4 can be adjusted. For the crushing operation, the roller crusher 1 is preset to have a specific distance between the rollers, the so-called starting gap G. This Figure 3A The starting gap G is selected based on several different factors, such as the size of the roller crusher (i.e., the diameter of the grinding rollers), the desired characteristics of the crushed material, etc. The starting gap G can be in the range of 10 to 140 mm. However, typically, the starting gap G is in the range of 60 to 90 mm.

[0169] The roller crusher 1 further comprises a movement blocking device 20 which is constructed and arranged to limit the gap G between the rollers to a minimum gap M. There are many different ways of providing such a movement blocking device 20 known in the prior art and therefore will not be discussed in detail here. A common solution ( Figure 1 The solution shown) is to provide a pair of mechanical engagement elements 20a, 20b on the bearing seats 35, 35'. For some roll crushers and / or materials to be crushed, the minimum gap M may be relatively small, for example in the range of 10 mm to 30 mm. However, typically, the minimum gap M is at least 45 mm. However, it is conceivable that the minimum gap is larger, for example at least 55 mm, or at least 60 mm, or at least 65 mm or at least 70 mm.

[0170] As previously mentioned, a problem with this type of grinding assembly is that material tends to accumulate at the corner 40 between the envelope surface 37 of the grinding roller 3 and the inner surface 39 of the flanges 36, 36' (see FIG. Figure 3A ) at. Figure 3A The schematic diagram shows the Figure 1 and Figure 2A This material accumulation 41 of the roller crusher 1 is often undesirable because it creates an increased local load in this area during operation, which may cause wear, damage and / or deformation on the opposite grinding roller 4 without flanges and the flanges 36, 36'. In order to provide a solution to this problem, a means for removing at least a portion of this material accumulation 41 is provided. The present disclosure relates to such a means in the form of a scraper device 200 utilizing a mechanical scraper 100. First, reference will be made to FIG. 3A to FIG. 3C The mechanical scraper 100 is discussed below with reference to Figures 3A to 10 Scraper assemblies 200, 200' and 300 are described.

[0171] Figure 3B A front view of a mechanical scraper 100 according to an embodiment of the present disclosure is shown. The mechanical scraper 100 is attached to a scraper device 200, which will be described in detail later, but for the sake of clarity, is shown separately here relative to the grinding rollers 3, 4. The mechanical scraper 100 includes two wear-resistant members 102a, 102b arranged at one end of the scraper 100, thereby defining a scraping surface 104 that is generally facing the material to be removed. The expression "generally facing the material to be removed" means that the scraping surface 104 is arranged to be substantially orthogonal to the tangent of the roller surface. The arrangement of the scraping surface 104 will be discussed further later. The wear-resistant members 102a, 102b are attached to the scraper body 103 (at Figure 3B Not visible in the front view, but in Figure 3C ). Figure 3C As shown, the figure shows a top view Figure 3B The scraper 100 together with a portion of the roller 3 with the flange 36, when rotating toward the scraper 100 as shown by the arrow (the arrow indicates the tangential velocity of the rotating roller 3), the wear-resistant members 102a, 102b can be provided on the scraper body 103, so that the scraping surface 104 of the scraper 100 is arranged to be inclined relative to the normal line NS of the inner surface 39 of the flange 36, as defined in front of the scraping surface 104, and is inclined so that the distance L between the normal line NS and the scraping surface 104 is toward Figure 3C This makes it easier for the material, once scraped off, to be transported away from the corner 40 between the inner surface 39 of the flange 36 and the envelope surface 37 of the roller 3, thereby facilitating an efficient material removal process.

[0172] The nature of the material pile 41 and the speed at which the at least one mechanical scraper 100 and the material pile 41 encounter each other tend to cause the material removal to be substantially impact driven. Thus, when encountering the scraper, a large surface portion of the material pile 41 is more or less instantly destroyed, rather than the scraper creating a carved recess in the pile material over time. This is particularly true in the case of mechanical scrapers 100 and 100. Figure 3B and Figure 3C Schematically shown in FIG. It has been found that the remaining portion of the material accumulation 41 has a relatively uniform outer surface. It is not necessary to completely remove the material accumulation 41. Preferably, only a portion of the accumulation 41 should be removed. Partial removal of the material accumulation 41 will reduce the overall wear of the scraper 100 because the scraper is significantly less worn when it is positioned away from the roller surface 37.

[0173] It has been recognized that a preferred position of the scraper 100 may be one in which the scraper 100 is in a position such that the minimum roller distance S1 between the scraper 100 and the outer surface 37 of the roller 3 is at least 70% of the minimum gap M. The minimum roller distance S1 is at least 70% of the minimum gap M. Figure 3B It should be noted that for Figure 3B In the exemplary embodiment shown, the scraper 100 is constructed and arranged so that the distance between the scraper 100 and the outer surface 37 of the roller 3 is substantially constant. This means that the minimum roller distance S1 will coincide with a substantially constant distance. However, for other undisclosed embodiments, the scraper may be constructed and / or arranged so that the distance between the scraper 100 and the outer surface 37 of the roller 3 varies. For such embodiments, the minimum roller distance S1 will be the shortest distance between the scraper and the outer surface 37 of the roller 3. With the scraper 100 in this position with the minimum roller distance S1, the roller crusher 1 can be in operation for an economically acceptable period of time before the scraper 100 has worn to the extent that the distance between the scraper 100 and the outer surface 37 of the roller 3 will become close to the minimum gap M and the scraper 100 must be repositioned or replaced.

[0174] like Figure 3B As shown, the scraper 100 is positioned at a minimum flange distance S2 from the inner surface of the flange 36. Figure 3A and Figure 3BAs shown, this minimum flange distance S2 is greater than the distance F between the roller 4 and the inner surface 39 of the flange 36. This may seem somewhat surprising, because it is foreseeable that in order to completely avoid contact between the roller 4 and the material accumulation 41, the scraper 100 may miss the material that must be removed. However, positioning the scraper 100 closer to the flange 36 brings other disadvantages. First, it increases the risk of the scraper 100 being damaged by the flange 36 and / or the material accumulation 41 on the flange 36, and this risk increases as the distance from any moving surface decreases. Secondly, it increases the risk of damaging the flange 36 itself. By positioning the scraper 100 at a minimum flange distance S2 greater than the distance F, a reasonable compromise is obtained. A sufficient amount of material is removed from the accumulated material 41 at the flange 36 while keeping the scraper 100 at a safe distance from the flange 36, which leads to an extended scraper life and flange life. Preferably, the scraper 100 is positioned so that the minimum flange distance S2 between the scraper 100 and the inner surface 39 of the flange 36 is 1-25 mm. More preferably, the scraper 100 is positioned so that the minimum flange distance S2 between the scraper 100 and the inner surface 39 of the flange 36 is at least 11 mm. It has been found that the risk of flange damage is significantly reduced at this distance. Needless to say, flange bending is undesirable because this will allow material to slip out of the crusher gap at the sides, thus causing part of the material to bypass the roller crusher, with the end result that the material output from the roller crusher will not have the specified size distribution.

[0175] Scraper 100 only Figure 3B and Figure 3C , to allow defining a preferred position of the scraper 100 relative to the roller crusher 1, or more specifically relative to the envelope surface 37 and / or the flange 36 of the roller. Figures 4 to 21 , the scraper (e.g. Figure 3B How to install the scraper 100) on the scraper device 200, 200' for the roller crusher 1.

[0176] The scraper device 200, 200' is essentially a multi-scraper device with the ability to replace the scraper 100 at an operating position P located at the envelope surface 37 of the roller or the roller 3 with the flange 36. The ability to replace the scraper 100 is achieved by providing a rotatable multi-head scraper unit 210, 210' that carries the mechanical scraper 100. During operation of the roller crusher 1, one scraper 100 is located in the operating position P and performs scraping on the accumulated material 41 present at one end of the roller 3, while the other scraper 100 is located away from the envelope surface 37 of the roller and is therefore an idle scraper that does not perform any scraping. Therefore, at any point in time, only one scraper 100 of the scraping device 200 performs scraping. Reference will now be made to Figure 4 and Figure 5 Two different exemplary embodiments of rotatable multi-head scraper units 210, 210' are described.

[0177] Figure 4 A rotatable multi-head scraper unit 210' according to a first exemplary embodiment is shown. The rotatable multi-head scraper unit 210' has at least two scrapers 100 (for this specific exemplary embodiment: 3 scrapers 100), which are arranged tangentially around the rotatable multi-head scraper unit 210' at a corresponding radial distance T from the rotation axis A of the rotatable multi-head scraper unit 210'. For this exemplary embodiment, the scrapers 100 are equidistant from each other by 120 degrees. In other words, for this non-limiting exemplary embodiment, the rotatable multi-head scraper unit 210' is symmetrical. The rotatable multi-head scraper unit 210' comprises a spider 230', which is attached to a rotatably arranged shaft member 240', which in turn is rotatably attached to a part of the roller crusher via a support structure 250'. As mentioned above, each scraper 100 includes a scraper body 103 and two wear-resistant components 102a, 102b, which together have Figure 4 and Figure 5 104 is represented by the dotted area in the scraping surface 104. Each scraper 100 is releasably fixed to the star bracket 230' at the dedicated support structure 220 by bolting. The bolting allows an easy assembly process when preparing the rotatable multi-head scraper unit 210' to be installed on the roller crusher 1. The rotatable multi-head scraper unit 210' also includes a wear protection element 232', which is constructed and arranged to protect the peripheral edge of the star bracket 230' from wear. During the scraping operation, significant material will impact the rotatable multi-head scraper unit 210', and without the wear protection element 232', the star bracket 230' will be at risk of being irreversibly damaged even before all three scrapers 100 are in service. The rotatable multi-head scraper unit 210' is attached to the shaft member 240', and the shaft member 240' is rotatably attached to the support device 250'. The support device 250' is constructed and arranged to be connected to the frame 2 of the roller crusher 1. Figure 4 As shown, the periphery 248' of the rotatable multi-head scraper unit 210' has a radial extension K, which is at least 20 mm smaller than the minimum radial distance T of the pair of adjacent scrapers 100, when viewed from between a pair of adjacent scrapers 100 of the two or more scrapers 100. Figure 4 In the exemplary embodiment shown, the radial distance T is the same for all three scrapers 100, so the minimum radial distance will be Figure 4However, for alternative embodiments, a pair of adjacent scrapers may be disposed at different respective radial distances T from the axis of rotation A.

[0178] Providing a perimeter 248' that is at least 20 mm smaller than the minimum radial distance T of the pair of adjacent scrapers 100 can be advantageous because it makes it easier for the removed accumulated material 41 to leave the rotatable multi-head scraper unit 210'. If the perimeter 248' of the rotatable multi-head scraper unit 210' seen between a pair of adjacent scrapers 100 is too close to the minimum radial distance K, there is a risk that the removed accumulated material 41 may be stuck between the perimeter 248' and the envelope surface 37 of the roller 3.

[0179] The minimum difference (TK) between the radial extension K of the periphery 248' of the rotatable multi-head scraper unit 210' seen between a pair of adjacent scrapers 100 and the minimum radial distance T of the pair of adjacent scrapers 100 may vary with the roller diameter. The reason for this is that the crushing gap G generally increases with the roller diameter, resulting in a greater excess of accumulated material with a greater thickness accumulating on the flange 36 and / or on the envelope surface 37 at the end portion of the roller 3 adjacent to the flange 36. It is to be taken into account that the above-defined minimum difference must exceed the thickness of the accumulated material 41. Therefore, for a roller crusher 1 with a large crushing roller, the above-defined difference may have to be greater than 20 mm. The radial extension may be in the range of 20 to 150 mm less than the minimum radial distance of the pair of adjacent scrapers 100.

[0180] As those skilled in the art will readily appreciate, the above features may be less relevant to some exemplary embodiments than to other exemplary embodiments. Specifically, the above features may be less relevant to a rotatable multi-head scraper unit with a smaller number of scrapers than to a rotatable multi-head scraper unit with a larger number of scrapers. Figure 4 The exemplary embodiment shown has only three scrapers, so that if the perimeter 248 ′ is extended further outwards such that K>T-20 mm, the removed accumulated material 41 can also be removed.

[0181] Figure 5A rotatable multi-head scraper unit 210 according to a second exemplary embodiment is shown. The rotatable multi-head scraper unit 210 further comprises at least two scrapers (for this particular exemplary embodiment: comprising four scrapers 100a, 100b, 100c and 100d), which are arranged tangentially around the rotatable multi-head scraper unit 210 at respective radial distances T from the axis of rotation A of the rotatable multi-head scraper unit 210. The scrapers 100a-100d are equidistantly spaced apart, but in contrast to the first exemplary embodiment, the scrapers 100a-100d of the second exemplary embodiment are not equidistantly spaced apart from each other. Instead, all four scrapers 100 are unevenly distributed, so that they are generally arranged on one side of the rotatable multi-head scraper unit 210, leaving no scrapers on the other side of the rotatable multi-head scraper unit 210. In other words, the rotatable multi-head scraper unit 210 is asymmetrical. However, the scrapers 100a-100d and their associated support structures 220 can be connected to each other. Figure 4 The support structure of the first exemplary embodiment shown in is the same and is therefore not described further herein. Another way of describing the positioning of the scrapers 100a-100d is as scrapers in a queue. When the new rotatable multi-head scraper unit 210 is positioned on the roller crusher 1, the rotatable multi-head scraper unit 210 is arranged relative to the envelope surface 37 of the roller so that the scraper 100a will be positioned in the operating position P. Therefore, the scraper 100a will be the first scraper to perform scraping. For this reason, the scraper 100a is referred to herein as the "first scraper in the queue". The first scraper 100a in the queue is followed by scrapers 100b and 100c and finally scraper 100d, the latter of which is referred to herein as the "last scraper in the queue". For Figure 5 In the second exemplary embodiment shown, the first scraper 100a in the queue and the last scraper 100d in the queue are positioned so that they are separated by an angle of approximately 180 degrees upstream of the first scraper 100a in the queue. Therefore, although scrapers 100b and scrapers 100c are arranged downstream of the first scraper 100a in the queue, no scraper is arranged directly upstream of the first scraper 100a in the queue. Many alternative embodiments of the rotatable multi-head scraper unit are envisioned. For example, the first scraper in the queue and the last scraper in the queue can be positioned so that they are separated by an angle of at least 120 degrees upstream of the first scraper in the queue. The star bracket 230 of the rotatable multi-head scraper unit 210 is also asymmetric and has a periphery 248 on its scraper free side, which has a radially outward extension distance T a 、T b A rounded contour of only a portion of . Similar to Figure 4 In the first exemplary embodiment shown, the periphery 248 of the rotatable multi-head scraper unit 210 has a radial extension K as seen between a pair of adjacent scrapers 100a, 100b of the two or more scrapers 100a-100d.ab , the radial extension is greater than the minimum radial distance T of the pair of adjacent scrapers 100a, 100b. a At least 20mm smaller. Figure 5 In the exemplary embodiment shown, for the four scrapers 100a-100d, the radial distance T a 、T b Therefore, since scraper 100a is located slightly closer to the rotation axis A than scraper 100b, the minimum radial distance between adjacent scrapers 100a, 100b will be the radial distance T a The advantages of the above characteristics are usually related to Figure 4 The same as outlined in the first exemplary embodiment.

[0182] Providing an asymmetric rotatable multi-blade scraper unit 210 with a star bracket 230 formed in this manner provides an alternative way to minimize the problem of wear damage. Instead of actively protecting the rotatable multi-blade scraper unit by a wear protection element as in the first exemplary embodiment, the second exemplary embodiment minimizes damage by a design that minimizes the risk of material impacting the scraper 100 that is idling and waiting to be used as a scraper in operation. The rotatable multi-blade scraper unit 210 is releasably attached to the shaft member 240. It can be beneficial to use quick fasteners to provide a releasable attachment because this will reduce the time to replace the rotatable multi-blade scraper unit 210. Such a releasable fastening device can be, for example, a flange connector or a bushing. The bushing can be, for example, a tapered bushing, an XT bushing, or a QD bushing. For the second exemplary embodiment disclosed herein, a QD bushing 234 is used. Such a QD bushing 234 is well known in the art and will not be described further herein. The shaft member 240 is rotatably attached to the support device 250, and for the sake of clarity, Figure 5 The supporting device 250 is omitted in the figure, but will be described in detail later with reference to Figures 8 and 9. The supporting device 250 is constructed and arranged to be connected to the frame 2 of the roll crusher 1.

[0183] The advantage of the rotatable multi-head scraper unit 210, 210' contemplated by the present disclosure is that it can provide an active scraper and a series of spare scrapers in a relatively limited space at the grinding roller 3 of the roller crusher 1. It is conceivable that the rotatable multi-head scraper unit 210, 210' can be arranged at different positions relative to the grinding roller 3, depending on the type of roller crusher 1. This is particularly useful in Figure 6 , which discloses that the rotatable multi-head scraper unit 210' of the first exemplary embodiment is located at about 7 o'clock, that is, at the lower end of the roller 3, and Figure 7 2 shows that the rotatable multi-head scraper unit 210 of the second exemplary embodiment is located at about the 11 o'clock position, that is, at the upper end of the grinding roller 3.

[0184] The rotatable multi-head scraper unit 210, 210' of the present disclosure can be equipped with a scraper 100, which includes a wear-resistant member 102a, 102b, and the wear-resistant member 102a, 102b has a scraping surface 104 including polycrystalline diamond (PCD). The wear-resistant member 102a, 102b may also be referred to as a scraping element 102a, 102b in this article. Polycrystalline diamond (PCD) and its advantages will be further described in detail with reference to the following exemplary embodiments in the present disclosure.

[0185] Now refer to Figures 8A-9B Two exemplary embodiments of scraper devices are described, namely, scraper devices 200' and 200. The only difference between these two scraper embodiments is that in the first embodiment, Fig. 8A and Figure 8B The scraper device 200' is equipped with Figure 4 The rotatable multi-head scraper unit 210', while in the second embodiment, Fig.9A and Fig. 9B The scraper device 200 is equipped with Figure 5 The rotatable multi-head scraper unit 210. Since these two embodiments have so many common features, they will be described together here.

[0186] Both the rotatable multi-head squeegee unit 210' and the rotatable multi-head squeegee unit 210 can be releasably attached to the shaft member 240 via the QD bushing 234. The shaft member 240 extends from a first end 241, where the rotatable multi-head squeegee units 210, 210' are arranged, to a second end 242, where the shaft member 240 is connected to the rotary actuator 202, which will be described in detail later.

[0187] like Fig. 8A and Figure 8B As shown, the shaft member 240 is a stepped shaft. The shaft member 240 has a first shaft portion 243 connected to the first end 241 and a second shaft portion 244 connected to the second end 242. The first shaft portion 243 has a first shaft diameter D1, and the second shaft portion 244 has a second shaft diameter D2. The first shaft diameter D1 is smaller than the second shaft diameter D2, and the shaft member 240 has an annular surface 245, which is substantially transverse to the rotation axis A at the intersection between the annular surface 245 and the first shaft portion 243. The purpose of the annular surface 245 will be described below.

[0188] The scraper device 200', 200 also includes a support device 250, which is arranged to at least partially surround the shaft member 240 and is also arranged to be connected to the frame 2 of the roller crusher 1. The support device 250 includes a bracket 252 mounted on a mounting plate 258. The mounting plane (mounting plane, mounting plate) 258 is in turn connected to a support structure 64, which is connected to the frame 2 of the roller crusher 1 via a support rod 66 (see Fig.9A and Fig. 9B ).exist Fig.9A and Fig. 9B A portion of a dust enclosure 62 can also be seen in the figure, and the rotatable multi-head scraper unit 210 is arranged in the dust enclosure 62. However, as will be readily appreciated by those skilled in the art, the scraper assembly 200 is not supported by the dust enclosure 62. It extends through an opening 63 of the dust enclosure 62, but is fully supported by the frame 2.

[0189] The bracket 252 has through holes 254 on opposite sides thereof, through which the shaft member 240 extends. The bracket 252 has an inner space in which a first brake device B1 is housed, which is configured to prevent and / or limit the rotation of the rotatable multi-head scraper unit 210 during the scraping operation by applying a radially inwardly directed pressure on the shaft member 240. The first brake device B1 includes a friction element 262, which is arranged to surround the second shaft portion 244 of the shaft member 240 so as to abut against it. The first brake device B1 also includes a support element 264, which is made of an elastic material (for example, rubber or polyurethane). The support element 264 surrounds the friction element 262 and is arranged in a support structure 253, which, for an exemplary embodiment, forms a part of the bracket 252. The support structure 253 at least partially surrounds the support element 264, thereby serving to spatially constrain the support element 264 radially outwardly and axially in a direction toward the gear box 270. By fastening the bracket cap 255 to the bracket 252, the support element 264 is compressed from the outside. This compression of the support element 264 will affect its elastic material, causing it to expand in other directions, namely, axially towards the gearbox 270, radially outwardly and radially inwardly towards the friction element 262. Since the support structure 253 effectively prevents any expansion directed axially and radially outwardly, the end result will be that the support element 264 compresses the friction element 262, which in turn exerts pressure on the shaft member 240. As will be readily appreciated by those skilled in the art, this will create a potential rotational resistance or damping in the mechanical system, thereby providing a first braking device B1. Finally, the bracket cap 255 has a through hole 256, the diameter of which is smaller than the diameter of the adjacently arranged through hole 254b of the bracket 252. The diameter of the through hole 256 is selected to match the first shaft diameter D1 of the first shaft portion 243, while the through holes 254a and 254b are selected to match the second shaft diameter d2 of the second shaft portion 244. Importantly, the diameter of the through hole 256 is smaller than the second shaft diameter D2. This allows the shaft member 240 to be retained within the support device 250 (and thus retained on the roll crusher) using the bracket cap 255 when the bracket cap 255 is tightened relative to the bracket 252 (the shaft member 240 is retained from the other side by the gear box 270, which will be described below).

[0190] The rotary actuator 202 comprises a gearbox 270 and a steering wheel 279. The steering wheel 279 is attached to the drive shaft 277 of the gearbox 270 and is used to provide kinetic energy to the scraper device 200 in the form of a rotational movement to enable the rotating multi-head scraper unit 210 to rotate when a worn scraper (e.g., the first scraper 100a in the queue) needs to be replaced with a subsequent scraper in the queue (in this example: scraper 100b). The gearbox 270 comprises a gear train 272, which mechanically interconnects the drive shaft 277 with the shaft member 240. The gearbox 270 also comprises a housing 271, which supports the gear train and protects the gear train from foreign matter that may risk damaging the gear train 272. For the sake of clarity, in Fig. 8A Only part of the housing 271 is shown in FIG. Fig.9A and Fig. 9B The housing 271 is also shown in FIG. The drive train (gear train) 272 includes a drive gear 273 attached to a drive shaft 277. The drive gear 273 meshes with a first idler gear 274, which has a gear diameter greater than the gear diameter of the drive gear 273, thereby providing a gear ratio greater than 1. The first idler gear 274 is arranged on a first end of an idler shaft 278, and the second idler gear 275 is arranged on a second end of the idler shaft 278. Fig. 8A As shown, the second idler gear 275 is a worm, or sometimes a worm screw, which is a gear in the form of a screw. The second idler gear 275 engages a driven gear 276, which is connected to the shaft member 240. The driven gear 276 is a worm wheel that meshes with the worm. The second idler gear 275 and the driven gear 276 are sometimes referred to together as a worm drive. There are two purposes for providing a worm drive in the gearbox 270: first, the worm drive will allow the axis of rotation to change 90 degrees relative to the shaft member 240, which can be beneficial for some applications due to, for example, space limitations. Secondly, the worm drive provides a relatively large transmission ratio, which is also beneficial, as will be explained below.

[0191] The (total) transmission ratio of the gear train 272 is defined as the ratio between the number of revolutions of the drive gear 273 and the number of revolutions of the driven gear 276. This means that a transmission ratio greater than 1 will allow a larger number of revolutions generated by applying a lower torque to the drive gear 273 to be converted into a lower number of revolutions with a higher torque on the driven gear 276. A gearbox 270 having a gear train 272 with a transmission ratio greater than 1 can be beneficial for several reasons. First, as previously mentioned, it provides a method for converting low-torque rotations into high-torque rotations. This can be advantageous because it allows the rotatable multi-head scraper unit 210 to be manipulated by hand (in the exemplary embodiment by means of a steering wheel 279). However, the gearbox 270 of the scraper device 200 also has another function: it constitutes a braking device, referred to herein as the second braking device B2. As will be readily appreciated by a person skilled in the art, any gearbox will provide a certain degree of braking in the sense of preventing and / or limiting rotation. This function is caused by friction and inertial forces in the drive train. However, the ability of the gear train to act as a brake increases with the increase in the gear ratio (this is why we tend to use reverse gear or first gear after parking, because reverse gear and first gear have the largest gear ratio). In other words, the gear ratio will affect the degree of braking force that the gear box 270 can provide to the rotating multi-head scraper unit 210. Specifically, the braking force will increase with the increase in the gear ratio of the gear train 272.

[0192] Turn again Fig. 8A , Fig. 8A To most clearly illustrate these features, the scraper device 200', 200 may also include a third braking device B3 in the form of a ratchet device 280. The ratchet device 280 is disposed at one end of the idler shaft 278 and comprises a ratchet 281 attached to the idler shaft 278 and a pawl 283 pivotably disposed in the gear box 270. The pawl 283 is biased toward the ratchet 281 by means of a spring 284. The ratchet 281 comprises a plurality of asymmetric teeth 282, each having a moderate slope on one edge and a steeper slope on the other edge. When the teeth 282 move in the opposite (rearward) direction, the pawl 283 will catch on the steeply inclined edge of the first tooth 282 it encounters, thereby locking it on the tooth 282 and preventing any further movement in that direction.

[0193] Fig.10 FIG. 8 shows a sensor system 80 for a roller crusher 1 for use with a scraper device 400 according to an exemplary embodiment of the present disclosure. The scraper device 400 is similar to Fig. 8AThe scraper device 200' is similar to the scraper device 200', but differs in that it also includes a drive unit 70 in the form of a motor. The drive unit 70 is attached to the drive shaft 277, replacing the manually operated steering wheel 279 of the scraper device 200'. The sensor system 80 includes a sensor 82 for monitoring the state of the scraper device 400, and a control unit 50 operably connected to the sensor system 80 and the drive unit 70. Fig.10 As shown, the sensor system 80 monitors the condition of the rotatable multi-head scraper unit 210' from both sides. The sensor 82 may include, for example, an optical sensor, such as a laser-based optical sensor. The sensor 82 may alternatively or additionally include a non-optical sensor, such as a microwave sensor, a radar sensor, or any other non-optical sensor suitable for the task. This is advantageous because it allows automatic determination of when the worn scraper 100 needs to be replaced. It is conceivable that this replacement operation is available during the operation of the roller crusher 1, thus eliminating the need for the roller crusher to be shut down. In addition, the sensor system 80 may allow for improved predictions about when the roller crusher 1 must be shut down to replace a completely worn rotatable multi-head scraper unit 210'. For example, the sensor system 80 may be configured to determine how many of the at least two scrapers 100 are still available for scraping.

[0194] Finally, refer to Fig.11 A detailed description of a scraper device disclosed herein is provided. Fig.11 Shows Figure 4 A rotatable multi-head scraper unit 210' and a roller 3. The specific roller and / or rotatable multi-head scraper unit is not essential to the solution, and this should only be interpreted as an exemplary embodiment. An inherent advantage of the scraper device of the present disclosure is that the rotatable multi-head scraper unit allows the distance between the scraper performing the scraping operation (i.e., the scraper in operation) and the envelope surface of the roller to be adjusted by adjusting the angular position of the rotatable multi-head scraper unit. This built-in adjustment capability of the scraper device can allow adjustment of the thickness of the accumulated material allowed to remain on the envelope surface of the roller. It can also eliminate the need to mount all scrapers to the rotatable multi-head scraper unit in a manner that has exactly the same radial distance from the axis of rotation. In addition, it can allow compensation for scraper wear, which will be explained below.

[0195] Scraper (eg Fig.11The scraper 100 shown in the figure will be subject to wear during the scraping operation. Therefore, during the life of the scraper 100, the radial extension T of the scraper 100 (i.e., the radial distance from the rotation axis A of the rotatable multi-head scraper unit 210') will gradually decrease. This will cause the accumulated material 41 at the flange 36 to gradually thicken over time. In other words, even if the scraper 100 in operation continuously performs effective scraping of the accumulated material 41, the scraping operation will not be consistent in time. By adjusting the angular position of the rotatable multi-head scraper unit 210', the scraper 100 in operation can be moved to a position closer to the envelope surface 37, thereby compensating for the wear effects on the radial extension T of the scraper 100.

[0196] This is Fig.11 When the scraper 100 is first in the operating position, that is, when the rotatable multi-head scraper unit 210' is selectively rotated to place the scraper 100 in contact with the accumulated material 41, the scraper 100 is arranged at a distance H1 from the envelope surface 37 of the roller 3. Fig.11 1 is shown as a first operating position P1 (indicated by the line P1 defining the angular position of the scraper 100 in the dashed outline). When the scraper 100 has been partially worn during operation (not shown), the rotatable multi-head scraper unit 210' can selectively rotate the angle B to the second operating position P2, where the scraper 100 is alternatively arranged at a distance H2 from the envelope surface 37 of the roller 3, as defined by the unworn state of the scraper 100. It should be emphasized that the distances H1 and H2 here are defined for the unworn scraper 100. It is easy for a person skilled in the art to understand that if worn, the scraper 100 will not reach the distance H2 in the second operating position P2. On the contrary, the scraper 100 can, for example, reach the distance H1, or approach the distance H1 in its worn state in the second operating position P2.

[0197] Fig. 12A FIG. 5 shows a portion of a scraper device 500 according to another exemplary embodiment. The scraper device 500 includes a rotatable multi-head scraper unit 510. Fig. 12B The rotatable multi-head scraper unit 510 shown separately in FIG. 5 has at least two scrapers 501 (eight scrapers 501 for this specific exemplary embodiment) arranged tangentially around the rotatable multi-head scraper unit 510 at respective radial distances T from the axis of rotation A of the rotatable multi-head scraper unit 510. For the exemplary embodiment, the scrapers 501 are equally spaced 45 degrees from each other. In other words, for this non-limiting exemplary embodiment, the rotatable multi-head scraper unit 510 is symmetrical. As shown in FIG. Fig. 12A and Fig. 13BAs shown, the periphery 548 of the rotatable multi-head scraper unit 510 has a radial extension K, which is at least 20 mm smaller than the minimum radial distance T of the pair of adjacent scrapers 501, when viewed from between the two or more scrapers 501. Fig. 12A In the exemplary embodiment shown, the radial distance T is the same for all eight scrapers 501, so the minimum radial distance will be Fig. 12A The radial distance T defined in . The rotatable multi-head scraper unit 510 has an annular joint portion 511, and each scraper 501 is arranged to the annular joint portion 511. Each scraper 501 can be attached to the annular joint portion 511 by bolting, threading or clamping. The rotatable multi-head scraper unit 510 includes a star bracket 530, which is attached to a rotatably arranged shaft member 540, which in turn is rotatably attached to a part of the roller crusher via a support structure or bracket 550.

[0198] The scraper device 500 further includes a rotary actuator 580, which is arranged to selectively enable the rotatable multi-head scraper unit 510 to rotate so as to allow one of the at least two scrapers 501 to be operatively used at a time. The rotary actuator 580 is only used when Fig. 12A The rotary actuator 580 may be, for example, the one previously described with reference to Fig. 8A The rotary actuator 202 described above is different from the rotary actuator 202 described above, but may be different. Alternative embodiments of the rotary actuator will be described later. The scraper assembly 500 also includes at least one braking device 570, which is configured to prevent and / or limit the rotation of the rotatable multi-head scraper 510 unit during operation of one of the at least two scrapers 501. The at least one braking device 570 is only used when the at least one scraper 501 is in operation. Fig. 12A The at least one braking device 570 may be similar to that previously described with reference to Fig. 8A The at least one braking device B1 , B2, B3 described herein may be different, but may also be different. Alternative embodiments of the at least one braking device 570 will be described later.

[0199] like Fig. 12A As shown, the rotatable multi-head scraper unit 510 is arranged at the first end 512 of the scraper device 500, and the rotary actuator 580 is arranged at the opposite second end 514 of the scraper device 500. The rotatable multi-head scraper unit 510 extends in a reference plane RP orthogonal to the rotation axis A. It will be apparent when viewing the drawings that the reference plane RP is shown at different axial positions for different drawings. This is done to make it easier to understand the geometry of the scraper. However, the reference plane RP is always orthogonal to the rotation axis A.

[0200] like FIG. 12A to FIG. 12CAs shown, the star support 530 of the rotatable multi-head scraper unit 510 includes a main support structure 509 and at least two scraper support structures 520 (including four scraper support structures 520 in the exemplary embodiment). The scraper support structures 520 are releasably arranged relative to the main support structure 509 and are shaped as annular sectors that together form a ring. The releasable attachment can be achieved by bolting the elements together with the help of fastening bolts 518 that enter the through holes 513 and are fixed in the threaded holes 508. The fastening bolts 518 are fixed in the threaded holes 508. Fig. 12A Not visible in , but in Fig.19 It can be seen that Fig.19 Shown is the installation Fig. 12C Another exemplary embodiment of a rotatable multi-scraper unit on the main support structure 509. Fig. 12A As shown, the ring has an annular engagement portion 511. The purpose of providing two or more scraper support structures 520 is to allow them to be replaced individually on site without completely disassembling the scraper device 500. Within the scope of the present disclosure, there are many conceivable ways to provide scraper support structures. They may appear in different numbers, have different shapes, and support different numbers of scrapers. The scraper support structure 520 has a 90-degree circular sector design, so four scraper support structures 520 are required to completely surround the main support structure 509 to form the annular engagement portion 511.

[0201] Each scraper 501 includes a scraper body 503 and a scraping element 502. The scraping element 502 has a Fig. 12A and Fig. 12B The scraping surface 504 is indicated by a dotted area in FIG. The scraping element 502 of the scraper 501 has a scraping surface 504 including polycrystalline diamond (PCD).

[0202] As will be readily appreciated by those skilled in the art, diamond can be a single continuous crystal, or it can be composed of many smaller crystals (polycrystals). Large, clear, and transparent single crystals of diamond are commonly used as gemstones. Polycrystalline diamond (PCD) is composed of numerous small particles that are easily visible to the naked eye through strong light absorption and scattering; it is not suitable for use as a gemstone, but is used in industrial applications such as mining and cutting tools. Polycrystalline diamond is often described by the average size (or grain size) of the crystals that make it up. Grain sizes range from a few nanometers to hundreds of micrometers, and are often referred to as "nanocrystalline" and "microcrystalline" diamond, respectively.

[0203] For the scraper 501, the scraping element 502 also includes a wear-resistant material in which polycrystalline diamond (PCD) is at least partially embedded. In an alternative embodiment, the polycrystalline diamond (PCD) can be attached to the surface of the wear-resistant material of the scraping element 502. For an exemplary embodiment, the wear-resistant material is a sintered carbide including tungsten carbide and cobalt (as a binder). The binder content can typically be 10-15 weight percent. Other wear-resistant materials are also possible. Such alternative materials include other ceramic materials, such as titanium carbide or vanadium carbide; metal-ceramic composites, such as sintered carbides, such as titanium carbide, tungsten carbide or vanadium carbide, with cobalt as a binder; or metal matrix composites including titanium carbide, tungsten carbide or vanadium carbide.

[0204] In one embodiment, polycrystalline diamond (PCD) is embedded in tungsten carbide, vanadium carbide, or titanium carbide.

[0205] An advantage of a scraping surface 504 comprising polycrystalline diamond (PCD) is that the wear life of the scraper 501 can be significantly extended. Typically, such a scraping surface 504 will comprise a wear-resistant material such as ceramic or a composite material comprising tungsten carbide, titanium carbide, and vanadium carbide, but using a scraping surface 504 comprising polycrystalline diamond (PCD), the wear life can be extended by up to about 50 times compared to a composite material comprising, for example, tungsten carbide alone.

[0206] The scraping element may include a layer of polycrystalline diamond (PCD). The layer of polycrystalline diamond (PCD) may have a thickness of 0.4 to 3.2 mm, or 1.0 to 2.0 mm, or 1.35 to 1.8 mm, or 1.4 to 1.6 mm, or about 1.5 mm. The scraping surface of the scraper element may include two or more layers of polycrystalline diamond (PCD). The two or more layers may be attached to each other, for example, by an adhesive. The number of layers and / or the thickness of each layer may depend on the particle size and / or its application.

[0207] The diamond grain size of the scraped surface polycrystalline diamond (PCD) may be 0.8 to 30 μm as determined by image analysis using a scanning electron microscope (SEM).

[0208] The particle size of the diamond can be measured by various measurement techniques, such as a laser particle size analyzer or a scanning electron microscope (SEM). An example of a laser particle size analyzer is a Malvern particle size analyzer device based on laser diffraction. The value determined using a laser particle size analyzer can be an initial diamond particle size, which for some embodiments can then be subjected to high pressure and high temperature sintering. When the diamond particles have been sintered and compacted to form a scraped surface polycrystalline diamond (PCD), image analysis by means of a scanning electron microscope is used to determine the final microstructure particle size distribution, i.e., the diamond particle size of the scraped surface polycrystalline diamond (PCD).

[0209] In addition to the scraper element 502, each scraper 501 of the scraper device 500 also includes a scraper element 505 on a surface 506 facing the rotary actuator 580, which surface 506 includes polycrystalline diamond (PCD). The scraper element 505 can be similar to the scraper element 502 already described in detail herein. It is also conceivable that the scraper element 505 is different from the scraper element 502. For example, the PCD of the scraper element 502 may have different properties from the PCD of the scraper element 505. This can be beneficial because the scraper element 502 will generally face the material to be removed and may therefore be mostly exposed to material impact, while the scraper element 505 will be oriented so that the material will impact at a certain angle, which makes the scraper element 505 more susceptible to sliding wear rather than impact wear. The rotatable multi-head scraper unit 510 is constructed and arranged so that each scraper surface 504 is at least partially facing the tangential direction Y defined at the scraper surface 504 and oriented along the reference rotation direction Z of the rotatable multi-head scraper unit 510. In other words, the scraping surface 504 has a projection PP in a plane PA orthogonal to the tangential direction Y, which projection PP is greater than zero. As will be readily appreciated by a person skilled in the art, this achieves the effect that when the scraper device 500 is arranged on the roller crusher 1, the active scraper (i.e. Fig. 12A The scraping surface 504 of the scraper 501A in the embodiment of the present invention can be arranged so that it at least partially faces the material to be removed. Since each scraper surface 504 is arranged in a substantially identical manner along the reference rotation direction Z, when the scraper 501 having each scraping surface 504 is the active scraper 501A, each scraping surface 504 can at least partially serve as an impact surface.

[0210] Each scraper 501 is releasably fastened to the star bracket 530 at the scraper support structure 520 by bolting. The bolting allows an easy assembly process when preparing the rotatable multi-head scraper unit 510 to be installed on the roller crusher 1. The rotatable multi-head scraper unit 510 is attached to the shaft member 540, which is rotatably attached to the support device 550. The support device 550 is constructed and arranged to be connected to the frame 2 of the roller crusher 1.

[0211] like Fig.13A Best shown in Fig.13A Showing each scraper 501 of the scraper device 500 in more detail, the surface 506 facing the rotary actuator 580 has an extension E2 from the scraper element 502 tangentially towards its rear end 507. The scraper 501 is constructed and arranged so that the distance L2 between the surface 506 facing the rotary actuator 580 and the rotary actuator 580 decreases towards the scraper element 502 over at least a portion of the extension E2. The distance L2 is only Fig.13ASchematically shown by arrows and dashed boxes, it is intended to define the relative position of the rotary actuator 580 relative to the scraper 501. However, Fig. 12A The distance L2 is shown more realistically in FIG.

[0212] For an exemplary embodiment, the surface 506 facing the rotary actuator 580 is substantially flat. Therefore, for the scraper 501, the varying distance L2 as described above can be further represented by an angle β defined between the surface 506 facing the rotary actuator 580 and the reference plane RP, wherein the angle β is defined within a tangential plane TPS of the scraper 501, which is orthogonal to the reference plane RP. The angle β can be 5° to 25°, or 5° to 20°, or 5 to 15°, or 8 to 12°, or 10°. The angle β of the scraper 501, the reference plane RP, and the tangential plane TPS are Fig.13A Shown in.

[0213] like Fig.13A and Fig. 13C As shown, the tangential plane TPS of the scraper 501 is parallel to the tangential direction Y of the scraper 501, as defined at the scraper surface 504 and oriented along the reference rotation direction Z of the rotatable multi-head scraper unit 510, and the tangential plane TPS is orthogonal to the reference plane RP. Therefore, each of the at least two scrapers 501 has an associated tangential plane TPS, and since the scrapers 501 are tangentially arranged around the rotatable multi-head scraper unit 510, these tangential planes TPS are angled relative to each other.

[0214] Fig. 13C The view in and the following Fig. 14C , Fig. 15C , Fig. 16C and Fig. 17C The view in is along the lines of Fig. 13B The radial axis RA defined in is intercepted.

[0215] like Fig. 13B As best shown in FIG. 1 , each scraper 501 extends from a bottom end 517 along a scraper axis 514 toward the scraper element 502 in a reference plane RP. The scraper axis 514 forms a first acute angle A1 with a radial axis RA of the rotatable multi-head scraper unit 510 along a reference rotation direction Z, which intersects the scraper element 502. Fig. 12A As best shown in FIG. 1 , this achieves the effect of "tilting forward" of the scraper 501 when the scraper arrangement is arranged in the roller crusher 1. Furthermore, each scraping surface 504 extends in a plane SP having a normal NP which forms an acute angle A2 with the scraper axis 514 along the reference rotation direction Z. This further helps to turn the scraping surface 504 towards the material to be removed when the scraper arrangement is arranged on the roller crusher 1.

[0216] like Fig. 12A and in more detail as Fig. 13C As shown, the scraper 501 is arranged to form an axial protrusion 515 on the side of the rotatable multi-head scraper unit 510 facing the rotary actuator 580. Fig. 13C As shown, the protrusion 515 has an axial extension X. The axial extension may be in the range of up to 75 mm, or 5 to 50 mm, or 10 to 40 mm. This particular exemplary embodiment has a protrusion only on the side facing the rotary actuator 580 (i.e. the side that will face the flange 36 when the scraper device 500 is mounted on the roller crusher 1). However, it is conceivable that the at least two scrapers are arranged to form an axial protrusion on one or both sides of the rotatable multi-head scraper unit. For example, Figure 5 The rotatable multi-head scraper unit 210 shown in the drawing has scrapers 100a, 100b, 100c which extend visibly from the star support 230 on both sides thereof. One advantage of this is that when the scraper device 500 is arranged and operated on the roller crusher 1, the removed material, once having flowed along the surface 506 of the scraper 501 facing the rotary actuator 580 (and thus facing the flange 36 when mounted on the roller crusher 1), is easily removed through the wider gap between the inner surface 39 of the flange 36 and the remainder of the rotatable multi-head scraper unit 510 (for the exemplary embodiment, the remainder will be the main support structure 509 and the scraper support structure 520) and flows towards the center of the roller 3, rather than being squeezed and compressed between the rotatable multi-head scraper unit 510 and the inner surface 39 of the flange 36. The scraper device according to the present disclosure can be implemented in many different ways. In the following, reference will be made to Figures 14A to 17C A number of alternative embodiments of the scraper assembly are described in detail. The scraper assembly 600, 700, 800, 900 is defined herein as a scraper support structure 620 and its associated scraper 601, 701, 801, 901. Each of these scraper assemblies 600, 700, 800, 900 can be fastened to Fig. 12C Main support structure 509 is shown. Providing the same interface for different blade assembly styles allows for varying the number of blades on a rotatable multi-headed blade unit as well as the structure and characteristics of the individual blades attached to the blade support structure.

[0217] FIG. 14A to FIG. 14EA scraper assembly 600 according to an alternative embodiment of the present disclosure is shown. The scraper assembly 600 includes two scrapers 601 connected to each other and a scraper support structure 620. The scraper support structure 620 is similar to the previously described scraper support structure 520 in that it has the same interface for attachment to the main support structure 509 and it has the same 90 degree sector form factor. Therefore, the scraper support structure 620 provides the same releasable attachment as the scraper support structure 520, which is achieved by means of fastening bolts 518 that enter the through holes 613 and are fixed to the threaded holes 508 of the main support structure 509. The scraper support structure 620 also has through openings 614 distributed between the through holes 613. Reference will be made later Figures 19 to 21 The purpose of describing the through opening 614. Similar to the previous exemplary embodiment, the periphery 648 seen between a pair of adjacent scrapers 601 has a radial extension K that is at least 20 mm smaller than the minimum radial distance T of the pair of adjacent scrapers 601 (see Fig. 14B ). For the exemplary embodiment, the radial distance T is the same for all eight scrapers 601, so the minimum radial distance will be Fig. 14B The advantages of the above features are generally related to Figure 4 The same as outlined in the first exemplary embodiment.

[0218] Each scraper 601 is releasably arranged in the annular engagement portion 611 by means of a geometric locking engagement. The releasable arrangement of the scraper 601 on the scraper support structure 620 Fig.14E As best shown in Fig.14E As shown, the geometric locking engagement is at least partially defined by a protruding structure 660 of the scraper 601 inserted into an associated recess 662 of the annular engagement portion 611, wherein the protruding structure 660 and the associated recess 662 have complementary shapes. The recess 662 of the annular engagement portion 611 is defined on the side surface of the scraper support structure 620. The protruding structure 660 forms part of the scraper body 603, while the recess 662 forms part of the scraper support structure 620. The scraper 601 is releasably attached to the scraper support structure 620 by means of a fastening bolt 616 (see Fig.14E ).

[0219] Furthermore, scraper 601 is structurally different from scraper 501. In particular, scraper surface 604 is not oriented in the same manner. Scraper surface 604 is arranged to be inclined relative to normal line N of reference plane RP, as defined in front of scraper surface 604, and is inclined such that a distance L1 between normal line N and scraper surface is directed toward rotary actuator 580 (i.e., it is directed toward Fig. 14C See Fig. 12A and replace the scraper support structure 520 with the scraper support structure 620). Figure 3A-3C This particular feature of a scraper is described in slightly different terms.

[0220] For the exemplary embodiment, the scraping surface 604 is substantially flat. Therefore, for the scraper 601, the varying distance L1 as described above can be further expressed as an angle α defined between the scraping surface 604 and the normal N to the reference plane RP, wherein the angle α is defined in a tangential plane TPS of the scraper 601 that is orthogonal to the reference plane RP. Fig.14A and Fig. 14C The angle α may be 1° to 15°, or 2° to 10°, or 3° to 8°, or 4° to 6°, or 5°.

[0221] The scraper 601 shares some features with the scraper 501 already described. In particular, the scraper 601 also includes a scraper element 605 on one side thereof. The scraper element 605 includes a surface 606 containing polycrystalline diamond (PCD). The scraper 601 is constructed and arranged so that the surface 606 forms an angle β between the surface 606 facing the rotary actuator 580 and the reference plane RP, wherein the angle β is defined in a tangential plane TPS of the scraper 601 that is orthogonal to the reference plane RP. Another similarity is that the scraper 601 is arranged to form an axial protrusion 615 on the side of the rotatable multi-head scraper unit. As Fig. 14C As shown, the protrusion 615 has an axial extension X. The axial extension X may be in the range of up to 75 mm, or 5 to 50 mm, or 10 to 40 mm. Although the ranges disclosed above are currently preferred, it is conceivable that the axial extension X may also be greater than 75 mm. The axial extension may depend on the roller crusher 1, the operating conditions and the material to be crushed, among other things. Therefore, the axial extension X must be selected based on parameters such as (but not limited to) the crushing gap G, the size of the crushing rollers 3, 4 and the size of the accumulated material 41 to be removed. The larger the material accumulation 41, the larger the axial extension X may be required.

[0222] FIG. 15A to FIG. 15C A scraper assembly 700 according to another exemplary embodiment of the present disclosure is shown. The scraper assembly 700 is similar to the scraper assembly 600 already described and is therefore only briefly described here. Like reference numerals refer to like elements and have been described earlier in this document. The scraper assembly 700 includes the aforementioned scraper support structure 620 and two scrapers 701. The scrapers 701 differ from the scrapers 601 already described in that they do not have dedicated scraper elements on the sides of the scraper body 703. In addition, the scrapers 701 do not have angled side surfaces, i.e., the angle β=0 (see Fig.14A ). In order to provide a suitable form factor, the scraper body 703 is therefore slightly thicker than the scraper body 603. The scraper 701 is arranged to form an axial protrusion 715 on the side of the rotatable multi-head scraper unit. Fig. 15C As shown, the protrusion 715 has an axial extension X. The axial extension X may be in the range of up to 75 mm, or 5 to 50 mm, or 10 to 40 mm. FIG. 15A to FIG. 15C In the exemplary embodiment, the axial extension X is 15 mm. Similar to the previous exemplary embodiment, the periphery 748 seen between a pair of adjacent scrapers 701 has a radial extension K that is at least 20 mm smaller than the minimum radial distance T of the pair of adjacent scrapers 701 (see Fig. 15B ). For the exemplary embodiment, the radial distance T is the same for all eight scrapers 701, so the minimum radial distance will be Fig. 15B The advantages of the above features are generally related to Figure 4 The advantages of the first exemplary embodiment are the same as those of the first exemplary embodiment.

[0223] FIG. 16A to FIG. 16C A scraper assembly 800 according to another exemplary embodiment of the present disclosure is shown. The scraper assembly 800 is similar to the scraper assembly 700 already described and is therefore only briefly described here. Like reference numerals refer to like elements and have been described earlier in this document. The main difference between the scraper assembly 800 and the scraper assembly 700 is that the scraper 801 of the scraper assembly 800 is wider. This allows providing a protrusion 815 with a considerable axial extension X. For FIG. 16A to FIG. 16C In the exemplary embodiment, the axial extension X is 40 mm. To accommodate the wider form factor, both the scraper body 803 and the scraper element 802 are larger than FIG. 15A to FIG. 15C The scraper body 703 and the scraper element 702 in the scraper body 703 and the scraper element 702. Similar to the previous exemplary embodiment, the periphery 848 seen between a pair of adjacent scrapers 801 has a radial extension K that is at least 20 mm smaller than the minimum radial distance T of the pair of adjacent scrapers 801 (see Fig. 16B ). For the exemplary embodiment, the radial distance T is the same for all eight scrapers 801, so the minimum radial distance will be Fig. 16B The advantages of the above features are generally related to Figure 4 The advantages of the first exemplary embodiment are the same as those of the first exemplary embodiment.

[0224] FIG. 17A to FIG. 17CA scraper assembly 900 according to another exemplary embodiment of the present disclosure is shown. The scraper assembly 900 is similar to the scraper assembly 700 already described and is therefore only briefly described herein. Like reference numerals refer to like elements and have been described previously herein. The scraper assembly 900 includes a scraper 901 and a scraper support structure 620 already described. The scraper 901 differs from the scraper 701 already described in that the scraper 901 has a surface 919 that is angled relative to a reference plane RF. The surface 919 is oriented so that when the scraper assembly 900 is mounted on the main support structure 509 and the scraper device is mounted on a roll crusher, the surface 919 will face away from the flange 36. Therefore, as will be readily appreciated by those skilled in the art, the surface 919 will also face away from the rotary actuator 580 (see Fig. 12A ). Thus, in other words, the scraper 901 has a surface 919 facing away from the rotary actuator 580, which surface 919 has an extension E3 from its scraper element 602 tangentially towards its rear end 907, wherein the scraper 901 is constructed and arranged so that the distance L3 between the surface 919 facing away from the rotary actuator 580 and the rotary actuator 580 decreases towards the scraper element 902 over at least a portion of the extension E3. As is easily understood by a person skilled in the art, the distance L3 defined between the surface 919 facing away from the rotary actuator 580 and the rotary actuator 580 itself must inevitably be defined through the scraper 901 having said surface 919. In the context of defining the distance L3, the "surface" should therefore be interpreted as a mathematical or geometric surface. This is in Fig.17A , where the distance L3 is marked as a solid line outside the scraper 901 and as a dotted line inside the scraper 901.

[0225] For an exemplary embodiment, the surface 919 of the back-rotating actuator 580 is substantially flat. Therefore, for the scraper 901, the varying distance L3 described above can be further represented by an angle γ defined between the surface 919 of the back-rotating actuator 580 and the normal N to the reference plane RP, wherein the angle γ is defined within a tangent plane TPS of the scraper 901 that is orthogonal to the reference plane RP. The angle γ can be 1° to 45°, or 1° to 40°, or 1° to 30°, or 5° to 45°, or 5° to 25°, or 5° to 20°, or 5° to 15°, or 8° to 12°, or 10°. The angle γ of the scraper 901, the reference plane RP, and the tangent plane TPS are Fig.17A and Fig. 17C Shown in.

[0226] Similar to the previous exemplary embodiment, the periphery 948 seen between a pair of adjacent scrapers 901 has a radial extension K that is at least 20 mm smaller than the minimum radial distance T of the pair of adjacent scrapers 901 (see Fig. 17B). For the exemplary embodiment, the radial distance T is the same for all eight scrapers 901, so the minimum radial distance will be Fig. 17B The advantages of the above features are generally related to Figure 4 The advantages of the first exemplary embodiment are the same as those of the first exemplary embodiment.

[0227] Fig.18A and Fig.18B A further exemplary embodiment of the present disclosure is shown. In this case, the figures show a rotatable multi-head scraper unit 1010 comprising a star-shaped bracket 1030 arranged to be mounted on an axis, such as the axis 240, 540 of the exemplary embodiment of the scraper device disclosed previously. The rotatable multi-head scraper unit 1010 differs from the previous embodiments in that it comprises a scraper 1001 having a surface 1019 facing away from the rotary actuator 580 and a surface 1006 facing the rotary actuator 580, and wherein at least one of the surface 1019 facing away from the rotary actuator and the surface 1006 facing the rotary actuator comprises a ceramic insert 1090. Arranging ceramic inserts on these surfaces 1006, 1019 will extend the wear life of the scraper 1001. Similar to the previous exemplary embodiment, the periphery 1048 seen between a pair of adjacent scrapers 1001 has a radial extension K that is at least 20 mm smaller than the minimum radial distance T of the pair of adjacent scrapers 1001 (see Fig.18A ). For the exemplary embodiment, the radial distance T is the same for all ten scrapers 1001, so the minimum radial distance will be Fig.18B The advantages of the above features are generally related to Figure 4 The advantages of the first exemplary embodiment are the same as those of the first exemplary embodiment.

[0228] Fig.19 The complete assembly of two scraper devices 1100, 1100' according to the present disclosure is shown when arranged on the frame 1200 of the roller crusher 1. The scraper devices 1000 and 1000' are almost identical. The only difference between them is that the rotatable multi-head scraper unit 1110 is mounted in an opposite manner to the rotatable multi-head scraper unit 1110', thereby allowing the scraper surfaces 1104 of the scrapers 1101 to face the same direction despite the scraper devices 1000, 1000' being arranged in a mirrored manner.

[0229] Fig. 20The scraper device 1100 is shown in more detail. The rotatable multi-head scraper unit 1110 comprises four scraper support structures 620 (same as described with reference to the previous exemplary embodiment), each scraper support structure carrying two scrapers 1101, which means that the rotatable multi-head scraper unit 1110 comprises eight scrapers 1101. The scraper support structures 620 are mounted on the main support structure 509, which in turn is mounted on the shaft member 540 (see also Fig. 12C The scraper support structure 620 is covered by wear-resistant covers 1190a, 1190b, which will be referred to later. Fig.21 Further description. Fig. 20 In the embodiment, one of the four wear shields 1190b has been removed to expose the internal scraper support structure 620. Similar to the previous exemplary embodiment, the periphery 1148 seen between a pair of adjacent scrapers 1101 has a radial extension K that is at least 20 mm smaller than the minimum radial distance T of the pair of adjacent scrapers 1101 (see Fig. 20 ). For the exemplary embodiment, the radial distance T is the same for all eight scrapers 1101, so the minimum radial distance will be Fig. 20 The advantages of the above features are generally related to Figure 4 The same as that outlined in the first exemplary embodiment.

[0230] The scraping elements 1102 differ from the previously disclosed embodiments in that they are thicker and have a scraping surface 1104 having a front portion 1104a and a rear portion 1104b connected to each other. The front portion 1104a is arranged upstream of the rear portion 1104b so that the front portion 1104a will first encounter the material to be removed from the roller 3. When the scraper device 1100 is arranged on the roller crusher 1, the front portion 1104a will be arranged closer to the flange 36 than the rear portion 1104b. This can be advantageous because it allows a very strong impact force to be generated by the front portion 1104a on a local area of ​​the accumulated material on the roller 3 with the flange 36, thereby increasing the possibility of breaking a larger part of the material. The rear portion 1104b can then intervene and help further remove material from the roller 3 and / or convey the already removed material away from the flange 36. The front portion 1104a may include polycrystalline diamond (PCD). The rear portion 1104b may also include polycrystalline diamond (PCD). Fig. 20 As shown, the rear portion 1104b is angled relative to the front portion 1104a. Specifically, the rear portion 1104b is substantially flat and faces away from the rotary actuator 1180. Thus, an angle γ can be defined between the surface 1104b facing away from the rotary actuator 1180 and the reference plane RP defined above (see also Fig. 20 ). For the exemplary embodiment, the angle γ is 45°.

[0231] from Fig. 20 As can be seen in the drawings, another difference between the scraper device 1100 and the exemplary embodiments of the scraper devices described previously is the difference in the rotary actuator 1180 and the brake device 1170. The rotary actuator 1180 is provided by a first structure 1181 having a first set of through holes 1182 and a second structure 1183 having a second set of through holes 1184. The first structure 1181 is connected to the rotatable multi-head scraper unit 1110 via the shaft member 540, and the second structure 1183 is connected to the frame 1200 of the roller crusher 1. One or more bolts 1185 and limiters 1186 are also provided. The through holes 1182 of the first structure 1181 are arranged so that they overlap with at least some of the through holes 1184 of the second structure 1183 at predetermined angular positions along the periphery of the first structure 1181 and the second structure 1183. Bolts 1185 and limiters 1186 may be accommodated in at least some of the through holes 1182, 1184 to define a specific angular position of the rotatable multi-head scraper unit 1110 of the scraper device 1100. The rotary actuator 1180 is actuated by manually removing the bolts 1185 and limiters 1186 and manually rotating the first structure 1181 relative to the second structure 1183 by one or more angular positions until the unworn scraper 1101 enters a position to become a functional scraper. Manual rotation can be achieved by a wrench tool (not shown) that is designed to fit into two or more through holes 1182 of the first structure 1181. This process is convenient because the second structure 1183 has a smaller form factor than the first structure 1181, which allows easier access to the first structure 1181 with a wrench tool. In order to more easily find the angular position where the through holes 1182, 1184 overlap, the retainer 1186 can be inserted into one of the through holes 1182 of the first structure 1181. The abutment surface 11187 is defined on the frame 1200 so that when the retainer 1186 abuts the abutment surface 1201, the correct overlap between the through holes 1182, 1184 is achieved. After reaching the correct angular position, the bolt 185 is inserted into one or more overlapping through holes 1182, 1184 to fix the first structure 1181 to the second structure 1183, which marks the end of the actuation process. Alternatively, a hydraulic cylinder or any other suitable means can be used. The above method is for illustrative purposes only. Those skilled in the art are well aware of alternative methods that can be used to achieve the manual rotation.

[0232] As will be readily appreciated by a person skilled in the art, for this exemplary embodiment, the braking device 1170 is provided by the same structural features as the rotary actuator 1180. Specifically, for this exemplary embodiment, the braking device 1170 is a locking device 1170 configured to selectively lock the rotation of the rotatable multi-head scraper unit 1110 during operation of one of the at least two scrapers 1101. The locking device 1170 is releasable and is provided by a first structure 1181 and a second structure 1183 that are manually locked to each other by means of bolts 1185. In other words, the locking device 1170 is arranged to rotationally lock the first structure 1181 and the second structure 1183 relative to each other by inserting one or more bolts 1185 through overlapping associated through holes in the first set of through holes 1182 and the second set of through holes 1184. Therefore, the locking device 1170 is releasable.

[0233] Fig.21 The above-mentioned wear-resistant covers 1190a, 1190b are shown separately. The purpose of the wear-resistant covers 1190a, 1190b is to protect the rotatable multi-head scraper unit 1110 from wear during use on the roller crusher 1. The wear-resistant covers 1190a, 1190b include a first group of wear-resistant covers 1190a and a second group of wear-resistant covers 1190b. Each of these groups includes two or more wear-resistant covers 1190a, 1190b. As for the scraper support structure 620, the wear-resistant covers 1190a, 1190b are shaped as circular ring sectors that together form a circular ring, one on each side of the rotatable multi-head scraper unit 1110. The wear-resistant covers of the first group of wear-resistant covers 1190a have openings 1191 distributed mutually along their periphery. These openings 1191 are structures that allow the scrapers 1101 to extend through the wear-resistant covers 1190a, 1190b (see Fig. 20 ). An edge wall 1192 is provided between each of these openings 1191. These edge walls 1192 may protrude radially and axially, such as Fig.21As best shown. The wear shields of the first set of wear shields 1190a may also have a screw 1193 extending from the inwardly facing surface. When assembled together, the first set of wear shields 1190a together define a central opening 1194 for allowing the shaft member 540 to pass through the first set of wear shields 1190a. The second set of wear shields 1190b has edge walls 1195 along its periphery. These edge walls 1195 protrude axially. The wear shields 1190a, 1190b are designed so that after being assembled on the rotatable multi-head scraper unit 1110, the edge walls 1192 will meet the edge walls 1195 to form a continuous shield for protecting the inner portion of the rotatable multi-head scraper unit 1110 at its periphery. The second set of wear shields 1190b also includes through holes 1196, which are geometrically aligned to allow reception of a corresponding one of the screws 1193 of the first set of wear shields 160a-160c. Finally, the second set of wear shields 1190b have access openings 1197 aligned so that they allow access to the fastening bolts 118, as shown. Fig.19 The wear caps 1190a, 1190b are designed so that they can be mounted on the rotatable multi-head scraper unit 1110 after the scraper 1101 has been mounted on the rotatable multi-head scraper unit. This is done by inserting the screws 1193 of the wear caps of the first set of wear caps 1190a into the through openings 614 of the scraper support structure 620 (see for example Fig.14A and Fig. 15B ) and the through hole 519 of the main support structure 508 (see Fig. 12C ). Each through opening 614 and a corresponding one of the through holes 519 are positioned so that they are coaxially aligned with each other and with an associated one of the screws 1193 of the first set of wear covers 1190a. Once each of the wear covers of the first set of wear covers 1190a has been inserted into place, the second set of wear covers 1190b is assembled from the other side of the main support structure 509 by allowing each screw 1193 to pass through the associated through hole 1196. Finally, the fastening nut 1198 is used to secure the first set of wear covers 1190a to the second set of wear covers 1190b.

[0234] Those skilled in the art will recognize that the present disclosure is by no means limited to the preferred embodiments described above. On the contrary, within the scope of the appended claims, many modifications and variations are possible. In addition, by studying the drawings, the disclosure and the appended claims, those skilled in the art can understand and implement variations of the disclosed embodiments when practicing the claims.

[0235] Example

[0236] Embodiment 1. A scraper device for a roller crusher, comprising:

[0237] a rotatable multi-head scraper unit having at least two scrapers, the at least two scrapers being arranged tangentially around the rotatable multi-head scraper unit at respective radial distances from the axis of rotation of the rotatable multi-head scraper unit;

[0238] a rotary actuator arranged to selectively rotate the rotatable multiple-head squeegee unit to allow operative use of one of the at least two squeegees at a time; and

[0239] at least one braking device configured to prevent and / or limit the rotation of the rotatable multi-head scraper unit during operation of one of the at least two scrapers,

[0240] Each of the at least two scrapers comprises a scraping element having a scraping surface, the scraping surface comprising polycrystalline diamond (PCD), and wherein the rotatable multi-head scraper unit is constructed and arranged so that each scraping surface at least partially faces a tangential direction defined at the scraper surface and is oriented along a reference rotation direction of the rotatable multi-head scraper unit.

[0241] Embodiment 2. The scraper device according to embodiment 1, wherein the scraper element further comprises a wear-resistant material, and the polycrystalline diamond (PCD) is at least partially embedded in the wear-resistant material.

[0242] Embodiment 3. The scraper device according to embodiment 2, wherein the wear-resistant material is one of a ceramic material, a metal-ceramic composite material and a metal-based composite material.

[0243] Embodiment 4. A scraper device according to any one of embodiments 1 to 3, wherein the rotatable multi-head scraper unit is arranged at a first end of the scraper device, and the rotary actuator is arranged at an opposite second end of the scraper device, wherein the rotatable multi-head scraper unit extends in a reference plane orthogonal to the rotation axis.

[0244] Embodiment 5. The scraper assembly of embodiment 4, wherein each of the at least two scrapers has a surface facing the rotary actuator, the surface facing the rotary actuator comprising polycrystalline diamond (PCD).

[0245] Embodiment 6. A scraper device according to embodiment 4 or 5, wherein each scraping surface of the at least two scrapers is arranged to be inclined relative to the normal of the reference plane defined in front of the scraping surface, and is inclined so that the distance between the normal and the scraping surface decreases toward the rotary actuator.

[0246] Embodiment 7. A scraper device according to any one of Embodiments 4 to 6, wherein each of the at least two scrapers has a surface facing away from the rotary actuator, the surface facing away from the rotary actuator having an extension tangentially from its scraping element toward its rear end, wherein the scraper is constructed and arranged so that the distance between the surface facing away from the rotary actuator and the rotary actuator decreases toward the scraping element over at least a portion of the extension.

[0247] Embodiment 8. A scraper device according to any one of Embodiments 4 to 7, wherein each of the at least two scrapers has a surface facing the rotary actuator, the surface facing the rotary actuator having an extension tangentially from the scraping element toward its rear end, wherein the scraper is constructed and arranged so that the distance between the surface facing the rotary actuator and the rotary actuator decreases toward the scraping element over at least a portion of the extension.

[0248] Embodiment 9. The scraper device according to any one of embodiments 1 to 8, wherein the at least two scrapers are arranged to form an axial protrusion on one side or both sides of the rotatable multi-head scraper unit.

[0249] Embodiment 10. The scraper assembly according to embodiment 9, wherein the axial protrusion has an axial extension in the range of at most 75 mm, or 5 to 50 mm, or 10 to 40 mm.

[0250] Embodiment 11. A scraper device according to any one of Embodiments 4 to 10, wherein each of the at least two scrapers extends along a scraper axis in the reference plane toward the scraping element, and wherein the scraper axis forms a first acute angle with a radial axis of the rotatable multi-head scraper unit along the reference rotation direction, and the radial axis intersects the scraping element.

[0251] Embodiment 12. The scraper device according to embodiment 11, wherein each scraping surface of the at least two scrapers extends in a plane, the plane having a normal that forms an acute angle with the scraper axis along a reference direction.

[0252] Embodiment 13. A scraper device according to Embodiment 4, wherein each of the at least two scrapers has a surface facing away from the rotary actuator and a surface facing the rotary actuator, and wherein at least one of the surface facing away from the rotary actuator and the surface facing the rotary actuator includes a ceramic insert.

[0253] Embodiment 14. The scraper device according to any one of embodiments 1 to 12, wherein the rotatable multi-head scraper unit has an annular engagement portion, and wherein each of the at least two scrapers is releasably arranged to the annular engagement portion.

[0254] Embodiment 15. A scraper device according to Embodiment 14, wherein the rotatable multi-head scraper unit further comprises a main support structure and at least two scraper support structures, wherein the at least two scraper support structures are releasably arranged relative to the main support structure and are formed into circular sectors, the circular sectors together form a circular ring, and the circular ring has an annular joint portion.

[0255] Embodiment 16. The scraper arrangement according to embodiment 14 or 15, wherein each of the at least two scrapers is releasably arranged in the annular engagement portion by means of a geometric locking engagement.

[0256] Embodiment 17. The scraper assembly of embodiment 16, wherein the geometric locking engagement is at least partially defined by a protruding structure of the scraper that is inserted into an associated recess of the annular engagement portion, wherein the protruding structure and the associated recess have complementary shapes.

[0257] Embodiment 18. The scraper device according to embodiment 17, wherein the associated recess of the annular engagement portion is defined on a side surface thereof.

[0258] Embodiment 19. The scraper assembly of embodiment 17 or 18, wherein each scraper of the at least two scrapers comprises a scraper body, and wherein the protruding structure forms a part of the scraper body.

[0259] Embodiment 20: The scraper device according to any one of embodiments 1 to 19 further comprises a wear-resistant cover constructed and arranged to protect at least multiple parts of the rotatable multi-head scraper unit.

[0260] Embodiment 21. The squeegee device according to any one of embodiments 1 to 20, wherein the rotatable multi-head squeegee unit is releasably arranged in the squeegee device to allow replacement of the rotatable multi-head squeegee unit.

[0261] Embodiment 22. A scraper device according to any one of embodiments 1 to 21, wherein the at least one braking device includes a locking device, which is configured to selectively lock the rotation of the rotatable multi-head scraper unit during operation of one of the at least two scrapers.

[0262] Embodiment 23. The squeegee assembly of any one of embodiments 1 to 22, wherein the squeegee assembly has a rotational indexing capability for selectively rotating the rotatable multi-head squeegee unit between predetermined angular positions.

[0263] Embodiment 24. A scraper device according to any one of Embodiments 1 to 23, wherein the periphery of the rotatable multi-head scraper unit has a radial extension as viewed between a pair of adjacent scrapers among the two or more scrapers, and the radial extension is at least 20 mm smaller than the minimum radial distance between the pair of adjacent scrapers.

[0264] Embodiment 25. A roller crusher having two substantially parallel rollers arranged to rotate in opposite directions and separated by a gap, each roller having two ends, the roller crusher comprising:

[0265] a flange, attached to one end of one of the rollers,

[0266] The flange extends in the radial direction of the one roller, and

[0267] said flange having an extension (E) beyond the envelope surface of said one roller,

[0268] The roller crusher further comprises a scraper device according to any one of embodiments 1 to 24, wherein the rotatable multi-head scraper unit is arranged so that one of the at least two scrapers is selectively positioned at one end of a flanged roller by the rotary actuator, and is prevented and / or restricted from moving relative to the roller by the at least one braking device, thereby at least partially allowing the removal of material accumulated on the envelope surface of the roller at the end portion adjacent to the flange and / or on the flange.

[0269] Embodiment 26. A roller crusher according to embodiment 25, wherein the roller crusher comprises two flanges attached to opposite ends of one of the rollers, and wherein a respective scraper device according to embodiment 1 is arranged at each end of the one roller with flanges.

[0270] Embodiment 27. A method of operating a roller crusher for grinding granular material, wherein the roller crusher has two generally parallel rollers arranged to rotate in opposite directions and separated by a gap, each roller having two ends, the roller crusher comprising:

[0271] a flange, attached to one end of one of the rollers,

[0272] The flange extends in the radial direction of the one roller, and

[0273] said flange having an extension (E) beyond the envelope surface of said one roller,

[0274] wherein the roller crusher further comprises a scraper device according to any one of embodiments 1 to 24, wherein the rotatable multi-head scraper unit is arranged so that one of the at least two scrapers is selectively positioned at one end of a flanged roller by the rotary actuator and is prevented and / or restricted from moving relative to the roller by the at least one braking device; wherein the method comprises at least the following steps:

[0275] Material accumulated on the envelope surface at the end portion of the roller adjacent to the flange and / or on the flange is at least partially removed by one of the at least two scrapers.

Claims

1. A scraper device for a roller crusher, include: a rotatable multi-head scraper unit having at least two scrapers, the at least two scrapers being arranged tangentially around the rotatable multi-head scraper unit at respective radial distances from the axis of rotation of the rotatable multi-head scraper unit; a rotary actuator arranged to selectively rotate the rotatable multi-blade unit to allow one of the at least two blades to be operatively used at a time; as well as at least one braking device configured to prevent and / or limit the rotation of the rotatable multi-head scraper unit during operation of one of the at least two scrapers, Each of the at least two scrapers comprises a scraping element having a scraping surface, the scraping surface comprising polycrystalline diamond (PCD), and wherein the rotatable multi-head scraper unit is constructed and arranged so that each scraping surface at least partially faces a tangential direction defined at the scraper surface and is oriented along a reference rotation direction of the rotatable multi-head scraper unit. 2 . The scraper assembly according to claim 1 , wherein the scraper element further comprises a wear-resistant material, the polycrystalline diamond (PCD) being at least partially embedded in the wear-resistant material.

3. The scraper assembly according to claim 2, wherein the wear-resistant material is one of a ceramic material, a metal-ceramic composite material, and a metal-based composite material.

4. The scraper device according to any one of claims 1 to 3, wherein the rotatable multi-head scraper unit is arranged at a first end of the scraper device, and the rotary actuator is arranged at an opposite second end of the scraper device, wherein the rotatable multi-head scraper unit extends in a reference plane orthogonal to the rotation axis.

5. The scraper assembly of claim 4, wherein each of the at least two scrapers has a surface facing the rotary actuator, the surface facing the rotary actuator comprising polycrystalline diamond (PCD).

6. A scraper device according to claim 4 or 5, wherein each scraping surface of the at least two scrapers is arranged to be inclined relative to the normal of the reference plane defined in front of the scraping surface, and is inclined so that the distance between the normal and the scraping surface decreases toward the rotary actuator.

7. A scraper device according to any one of claims 4 to 6, wherein each of the at least two scrapers has a surface facing away from the rotary actuator, the surface facing away from the rotary actuator having an extension tangentially from its scraping element toward its rear end, wherein the scraper is constructed and arranged so that the distance between the surface facing away from the rotary actuator and the rotary actuator decreases toward the scraping element over at least a portion of the extension.

8. A scraper device according to any one of claims 4 to 7, wherein each of the at least two scrapers has a surface facing the rotary actuator, the surface facing the rotary actuator having an extension tangentially from the scraping element toward its rear end, wherein the scraper is constructed and arranged so that the distance between the surface facing the rotary actuator and the rotary actuator decreases toward the scraping element over at least a portion of the extension.

9. The squeegee device according to any one of claims 1 to 8, wherein the at least two squeegees are arranged to form an axial protrusion on one side or both sides of the rotatable multi-head squeegee unit.

10. Scraper arrangement according to claim 9, wherein the axial protrusion has an axial extension in the range of at most 75 mm, or 5 to 50 mm, or 10 to 40 mm.

11. A scraper device according to any one of claims 4 to 10, wherein each of the at least two scrapers extends along a scraper axis in the reference plane toward the scraping element, and wherein the scraper axis forms a first acute angle with a radial axis of the rotatable multi-head scraper unit along the reference rotation direction, and the radial axis intersects the scraping element.

12. The scraper device according to claim 11, wherein each scraping surface of the at least two scrapers extends in a plane having a normal which forms an acute angle with the scraper axis along a reference direction.

13. The scraper assembly of claim 4, wherein each of the at least two scrapers has a surface facing away from the rotary actuator and a surface facing the rotary actuator, and wherein at least one of the surface facing away from the rotary actuator and the surface facing the rotary actuator comprises a ceramic insert.

14. The squeegee device according to any one of claims 1 to 12, wherein the rotatable multi-head squeegee unit has an annular engagement portion, and wherein each of the at least two squeegees is releasably arranged to the annular engagement portion.

15. The scraper device according to claim 14, wherein the rotatable multi-head scraper unit further comprises a main support structure and at least two scraper support structures, wherein the at least two scraper support structures are releasably arranged relative to the main support structure and are formed into circular sectors, the circular sectors together form a circular ring, and the circular ring has an annular joint portion.

16. Scraper arrangement according to claim 14 or 15, wherein each of the at least two scrapers is releasably arranged in the annular engagement portion by means of a geometric locking engagement.

17. Scraper assembly according to claim 16, wherein the geometric locking engagement is at least partially defined by a protruding structure of the scraper that is inserted into an associated recess of the annular engagement portion, wherein the protruding structure and the associated recess have complementary shapes.

18. A scraper assembly according to claim 17, wherein the associated recess of the annular engagement portion is defined on a side surface thereof.

19. The squeegee assembly according to claim 17 or 18, wherein each of the at least two squeegees comprises a squeegee body, and wherein the protruding structure forms a part of the squeegee body.

20. The squeegee assembly according to any one of claims 1 to 19, further comprising a wear-resistant cover constructed and arranged to protect at least portions of the rotatable multi-head squeegee unit.

21. The squeegee device according to any one of claims 1 to 20, wherein the rotatable multi-head squeegee unit is releasably arranged in the squeegee device to allow replacement of the rotatable multi-head squeegee unit.

22. The squeegee device according to any one of claims 1 to 21, wherein the at least one braking device comprises a locking device configured to selectively lock the rotation of the rotatable multi-head squeegee unit during operation of one of the at least two squeegees.

23. The squeegee assembly according to any one of claims 1 to 22, wherein the squeegee assembly has a rotational indexing capability for selectively rotating the rotatable multi-head squeegee unit between predetermined angular positions.

24. A scraper device according to any one of claims 1 to 23, wherein the periphery of the rotatable multi-head scraper unit has a radial extension as viewed between a pair of adjacent scrapers among the two or more scrapers, and the radial extension is at least 20 mm smaller than the minimum radial distance between the pair of adjacent scrapers.

25. A roller crusher having two substantially parallel rollers arranged to rotate in opposite directions and separated by a gap, each roller having two ends, the roller crusher include: a flange, attached to one end of one of the rollers, The flange extends in the radial direction of the one roller, and The flange has an extension (E) beyond the envelope surface of the roller, The roller crusher further comprises a scraper device according to any one of claims 1 to 24, wherein the rotatable multi-head scraper unit is arranged so that one of the at least two scrapers can be selectively positioned at one end of a flanged roller by the rotary actuator, and is prevented and / or restricted from moving relative to the roller by the at least one braking device, thereby at least partially allowing the removal of material accumulated on the envelope surface of the roller at the end portion adjacent to the flange and / or on the flange.

26. A roller crusher according to claim 25, wherein the roller crusher comprises two flanges attached to opposite ends of one of the rollers, and wherein a respective scraper device according to claim 1 is arranged at each end of the flanged one roller.

27. A method of operating a roller crusher for grinding granular material, wherein the roller crusher has two substantially parallel rollers arranged to rotate in opposite directions and separated by a gap, each roller having two ends, the roller crusher include: a flange, attached to one end of one of the rollers, The flange extends in the radial direction of the one roller, and said flange having an extension (E) beyond the envelope surface of said one roller, The roller crusher further comprises a scraper device according to any one of claims 1 to 24, wherein the rotatable multi-head scraper unit is arranged so that one of the at least two scrapers can be selectively positioned at one end of the flanged roller by the rotary actuator and is prevented and / or limited from moving relative to the roller by the at least one braking device; wherein the method comprises at least the following steps: Material accumulated on the envelope surface at the end portion of the roller adjacent to the flange and / or on the flange is at least partially removed by one of the at least two scrapers.

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