Roll crusher and scraper device for roll crusher

Abstract

The utility model provides a roller crusher and a scraper device for 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 scrapers each comprise a scraping element having a scraping surface, where the scraping surface comprises polycrystalline diamond (PCD), and the rotatable multi-head scraper unit is constructed and arranged such that each scraping surface at least partially faces a tangential direction defined at the scraper surface and oriented along a reference rotational direction of the rotatable multi-head scraper 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 this gap. A roller crusher is called a high-pressure grinding roller or a high-pressure roller crusher. This type of crushing has been described in US4357287, in which it was determined that when trying to achieve fine and / or very fine crushing of the material, it is not actually necessary to strive for the breakage of individual particles. On the contrary, it has been found that by introducing a sufficiently high compressive force so that briquetting or agglomeration of the particles occurs during the crushing, significant energy savings and increased production can be achieved. This crushing technology is called intergranular crushing. Here, the material to be crushed or comminuted is not only crushed by the crushing surfaces of the rollers, but also by the particles in the material to be crushed, hence the name intergranular crushing. US4357287 points out that this "agglomeration" can be achieved by using higher compressive forces than before. For example, previously, up to 200 kg / 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 achieve only 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, meaning 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 filling to a certain height above the gap to keep the gap full and maintain particle-to-particle compression. This will increase throughput and reduce the need for finer materials. This is in sharp contrast to earlier solutions, which always emphasized that single particle breakage was the only way to achieve fine and very fine particle size reduction.

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

[0004] To maintain the crushing effect along the entire length of the grinding rollers, flanges can be placed at the ends of the crushing rollers; one flange at each end of a roller, or one flange at one end of each roller, but located at opposite ends of the roller crusher. This arrangement creates a more efficient and uniform feed inlet to the rollers. The flanges allow for feed that produces optimal material pressure across the entire length of the crushing rollers. It has been shown that the use of flanges can increase the production capacity of a given roller crusher by up to 20%, sometimes even more. A common problem with grinding rollers without flanges is that the ratio between roller diameter and roller width is very important due to the significant edge effect (i.e., reduced crushing effect at the roller edges). This is because material can overflow from the edges of the rollers, reducing the crushing pressure on the material entering the gap at the roller edges. Therefore, without flanges, it is necessary to recover material that escapes the rollers, as well as some material that has passed through the gap at the edges of the crushing rollers due to reduced fracture caused by the lower pressure at the edges.

[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 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 scrapers. Utility Model Content

[0008] According to a first embodiment of the present disclosure, this 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 arranged tangentially around the rotatable multi-head scraper unit at respective radial distances from the rotation axis of the rotatable multi-head scraper unit. The scraper device further 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 operatively used at a time, the braking device being configured to prevent and / or limit 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 being constructed and arranged such 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] The expression "each scraper 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" means that the scraper surface has a projection greater than zero in a plane orthogonal to the tangential direction. As will be readily understood by a person skilled in the art, this achieves the effect that, when the scraper arrangement is arranged on a roller crusher, the scraper 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 manner along the reference rotation direction, when the scraper having each scraper surface is the active scraper, each scraper surface can at least partially serve as an impact surface. The scraper surface can be planar or non-planar. If the scraper surface is planar, its normal can be parallel to or substantially parallel to the tangential direction. However, if the scraper surface is non-planar, its normal can alternatively form an acute angle with the tangential direction. As will be readily understood by a person skilled in the art, both alternatives result in a non-zero projection in a plane orthogonal to the tangential direction, and both alternatives result in the effect that, when the scraper arrangement 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. 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 worn scrapers with new scrapers as the active scrapers, it is also conceivable that the rotatable multi-head scraper unit can be rotated opposite the reference direction of rotation in order to replace worn scrapers with new scrapers as the active scrapers.

[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 would comprise 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 comprising, 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 attached 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 (hard alloys) 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 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. Once the diamond particles have been sintered and compacted to form the impact surface polycrystalline diamond (PCD), image analysis with the aid of a scanning electron microscope is used to determine the final microstructural particle size distribution, i.e., the diamond particle size of the impact surface polycrystalline diamond (PCD).

[0021] One advantage of the disclosed scraper arrangement is that the arrangement enables a compact scraper arrangement, which reduces the space required for assembly into the roller crusher. Another advantage is that it reduces maintenance time for replacing worn scrapers, wherein unused new scrapers on a rotatable multi-head scraper unit can be simply repositioned into an operating position by rotating the rotatable multi-head scraper unit, without having to completely shut down the roller crusher for scraper replacement. Another advantage of the scraper arrangement is that it allows for an easier replacement procedure should a scraper replacement become necessary. 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, thereby effectively replacing two or more individual scrapers in one replacement operation.

[0022] Another advantage is that the ability to rotate the multi-head scraper unit allows for a fully automated scraper replacement procedure. In contrast to 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 assembly contemplated by the present disclosure allows for 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 that has 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 "braking device" as used herein should be interpreted broadly. The term is used herein to refer to any arrangement that is constructed and arranged to prevent and / or limit rotation of the rotatable multiple scraper unit during operation of one of the at least two scraper blades. Thus, the term "braking device" naturally includes typical braking systems, such as friction brakes and clutches. However, the term "braking device" must also be interpreted to include mechanical systems, such as gear trains and any other mechanical linkages, whether or not they are used to perform additional tasks within the device, that are also constructed and arranged to prevent and / or limit rotation of the rotatable multiple scraper unit during operation of one of the at least two scraper blades. A "braking device" can be configured to prevent and / or limit rotation of the rotatable multiple scraper unit to varying degrees. Some braking devices contemplated by the present disclosure can be configured to provide a reaction torque on the rotatable multiple scraper unit that is sufficiently strong to prevent undesirable rotation during normal operation, but still selected to allow rotation of the rotatable multiple scraper unit in the event that excessive accumulated material impacts the scraper blades of the rotatable multiple scraper unit. This can be advantageous because it provides a means of releasing the rotatable multi-head squeegee unit from its operating position in the event of an impact force high enough to damage the squeegee arrangement. That is, it is also conceivable that the "braking device" of 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 those skilled in the art, the rotation of the rotatable multi-head scraper unit is provided to reposition the individual scrapers of the rotatable multi-head scraper unit relative to the roller surface. This means that the rotatable multi-head scraper unit is not rotated during the scraping operation. In other words, the scraper device is configured to prevent and / or limit the rotation of the rotatable multi-head scraper unit during the crushing operation so that it remains stationary relative to the roller crusher.

[0026] According to one embodiment, the rotatable multi-headed squeegee unit is arranged at a first end of the squeegee arrangement and the rotary actuator is arranged at an opposite second end of the squeegee arrangement, and wherein the rotatable multi-headed 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 that includes polycrystalline diamond (PCD). Similar to the PCD on the scraping surface, also on this surface facing the rotary actuator, the 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 a normal to a 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 having such an arrangement of scraping surfaces is that, in the case where the scraper arrangement is arranged and operated in a roller crusher, 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 can be substantially flat. Therefore, according to this embodiment, the varying distance described above can 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 within a tangential plane of the scraper that is orthogonal to the reference plane. The angle α can be 1° to 15°, or 2° to 10°, or 3° to 8°, or 4° to 6°, or 5°.

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

[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 scrapers are 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 scrapers. Therefore, the expression "extension in the tangential direction..." should be interpreted broadly and be read as including any surface having an extension or dimension that is essentially parallel to the tangential direction at the position of the scraper element. This extension does not have to be the main extension of the scraper, as will be further described in the permissible disclosure. The advantage of providing such an arrangement for the surface facing the rotary actuator is that, where the scraper arrangement 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. Thus, according to this embodiment, the varying distance described above can be further expressed as an angle β defined between the surface facing the rotary actuator and a reference plane, wherein the angle β is defined within a tangential plane of the scraper that is orthogonal to the reference plane. The angle β can be 1° to 45°, 1° to 40°, 1° to 30°, 5° to 25°, 5° to 20°, 5° to 15°, 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 tangentially from its scraping element towards its rear end, wherein the scrapers are constructed and arranged so that the distance between the surface facing away from the rotary actuator and the rotary actuator decreases towards 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 will be readily 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 said surface. In the context of defining a 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 towards the center of the roller.

[0034] According to one embodiment, the surface facing away from the rotary actuator comprises a substantially flat surface. Thus, for this embodiment, the varying distance described above can be further expressed as an angle γ defined between the surface facing away from the rotary actuator and a reference plane, wherein the angle γ is defined within a tangential plane of the scraper that is 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°. While the angle is preferably such that the distance between the surface facing away from the rotary actuator and the rotary actuator decreases over at least a portion of its extension toward the scraping surface, it is also contemplated to provide a scraper having a surface facing away from the rotary actuator that is configured such that the distance between the surface facing away from the rotary actuator and the rotary actuator increases over at least a portion of its extension toward the scraping surface. As will be readily appreciated by those skilled in the art, for a substantially flat surface, this would be defined using the above definition using a negative angle γ. For such embodiments, the angle γ would 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 axial protrusions 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 remainder 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 axial protrusions toward the flange, the distance between the active scraper and the flange is narrower than the distance between the remainder 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 easily removed through the wider gap between the inner surface of the flange and the remainder of the rotatable multi-head scraper unit and flows 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.

[0036] According to one embodiment, 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. 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, among other things, the roller crusher, the operating conditions, and the material to be crushed. 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 accumulated material to be removed. Larger material build-ups may require a larger axial extension.

[0037] According to one embodiment, each of the at least two scrapers extends in a reference plane along a scraper axis toward the scraper element, and wherein the scraper axis forms a first acute angle with a radial axis of the rotatable multi-head scraper unit along a reference rotation direction, the radial axis intersecting the scraper element. One advantage of this is that 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 that forms an acute angle with the scraper axis along the reference direction. Also, an advantage of this is that during operation, the forces acting on the scraper elements 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, the 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 includes a ceramic insert. The placement of the ceramic insert on these surfaces increases 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 the 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 for 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 circular ring sectors that together form a circular ring with an annular joint. In principle, the rotatable multi-head scraper unit can 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 them to be mounted on the main support structure, which is rotatably arranged on the through-shaft. The at least two scraper support structures can have the same size. Therefore, for an embodiment with two scraper support structures, each scraper support structure can form a 180-degree circular ring sector. Alternatively, for an embodiment with three scraper support structures, each scraper support structure can form a 120-degree circular ring sector. Alternatively, for an embodiment with four scraper support structures, each scraper support structure can form a 90-degree circular ring sector. It is also conceivable that the 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 together form a ring, and the ring will have an annular joint. These exemplary embodiments can be advantageous because they provide modularity in the design, thereby facilitating easier and faster maintenance. By providing at least two scraper support structures, a complete module including several scrapers can be removed from a scraper assembly in a single operation. This can also improve speed and reliability when replacing scrapers on a scraper assembly, as each scraper can be replaced by simply replacing 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 impact 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 of providing a locking engagement. This is achieved by providing complementary shapes on the at least two scrapers and the annular joint 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 of providing a locking engagement can be to provide a plurality of radially inwardly directed holes on the periphery of the annular joint portion and allow the scrapers to extend into these holes. They can then be fixed to the annular joint portion by bolting. As will be readily appreciated by those skilled in the art, the bolts will not absorb most of the torsional loads, which will instead 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 for easier replacement. Providing the recess on the side surface of the annular engagement portion can reduce the risk of sticking between the annular engagement portion and the scraper blade 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 assembly further comprises a wear-resistant cover constructed and arranged to protect at least a portion of the rotatable multi-head scraper unit. The wear-resistant cover can be advantageous because it allows the rotatable multi-head scraper unit to be protected from the harsh environment in which it is intended to operate. Typically during crusher operation, particularly during the removal of accumulated material from the flanged rollers, a high density of high-speed stones, sand, and dust will continuously impact the surface of the rotatable multi-head scraper unit, thereby increasing the risk of wear on the parts and 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 multiple-head scraper unit is releasably arranged in the scraper device to allow replacement of the rotatable multiple-head scraper unit. For example, such a replacement of the rotatable multiple-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 will be readily 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 worn out. 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 greater 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 queue and the last scraper in the queue are positioned such that they are separated by an angle of at least 120 degrees upstream of the first scraper in the queue.

[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-head scraper unit when the scraper arrangement has been installed in the roller crusher or when a new rotatable multi-head scraper unit has been arranged on the scraper arrangement. It should be understood that this term is not necessarily used to distinguish a specific scraper among the at least two scrapers on the rotatable multi-head scraper unit. The first scraper in the queue can be any 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-head scraper unit, the at least two scrapers can be positioned so that one scraper will naturally be the first scraper in the queue. This applies to such rotatable multi-head scraper unit in which the at least two scrapers are unevenly distributed on the rotatable multi-head 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 roller 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 line" refers to the area in front of the scraping surface of the first scraper in the line that will encounter any accumulated material as the rollers of the roller crusher rotate during operation of the roller crusher. Thus, the "stream" in this context would 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 impacts the scraper surface as a "stream" of material during crushing operations. However, as will be readily understood by those skilled in the art, "upstream" is used herein only to define a direction, and thus this expression should not be construed as limiting the distribution of material at the flange in any particular way.

[0054] One 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 scrapers and therefore 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 queue and the last scraper in the queue are positioned such that they are separated by an angle of at least 140 degrees upstream of the first scraper in the queue.

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

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

[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 very little impact on the back surface of the last scraper in the queue, because the accumulated material scraped off will pass through the rotatable multi-head scraper unit in an area where neither scraper is arranged tangentially at a radial distance from the axis of rotation 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 operation of the second scraper in the queue, the accumulated material scraped off 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 on its back surface is of no concern while 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. During 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 applies to 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 distances at which the other scrapers of the at least two scrapers are arranged. It is also conceivable that the at least two scrapers are arranged at different radial distances from the axis of rotation of the rotatable multi-head scraper unit.

[0062] The purpose of providing different distances may be to allow for convenient selection of the degree of scraping. For example, there may be situations where a higher degree of tolerance for accumulated material is required than in other situations. This may occur, for example, when a roller crusher is operated with a relatively large crushing gap. In such cases, the rotatable multi-head scraper unit can be rotated to interchange a scraper positioned closer to the roller with another scraper positioned further away from the roller.

[0063] According to one embodiment, the scraper device may further comprise 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 remotely. This is particularly advantageous on roller crushers where the rotatable multiple scraper unit must be positioned in the flange area of ​​the roller, which 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, such that the rotatable multiple scraper unit is positioned on one side of the wall / structure and the rotary actuator is positioned 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 a number of optional ways. For example, the rotatable multi-head scraper unit can be releasably attached to the shaft member by a releasable fastening device (e.g., 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 further 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 the rotatable multi-head scraper unit to be replaced 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 that engage 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 a 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 elastic element. The other element may be made of rubber or polyurethane. Using an elastic element may be advantageous because it allows for more uniform application of pressure on the shaft member or engagement element in response to external forces acting on the elastic element.

[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 engagement with the shaft member or engagement element to be initiated by exposing the resilient friction element or resilient support element to a compressive force having any direction relative to the shaft. This technical effect occurs because the resilient 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 resilient friction element or resilient support element within the support structure. Therefore, there is no need to apply a compressive force on the resilient element in a direction substantially parallel to the direction in which the resilient element engages the shaft member or engagement element. As long as the resilient element is compressed, it will expand in a direction toward the shaft member or engagement element, thereby applying pressure thereto.

[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 portion of a transmission system that includes a gear train comprising at least one drive gear to which torque is applied and a driven gear that is mechanically connected to the drive gear and transmits torque from the gearbox. A simple gearbox may consist of only a drive gear and a driven gear. In such a gearbox, the drive gear meshes directly with the driven gear. The gearbox may optionally include one or more additional intermediate gears, also known as idler gears, that interconnect the drive gear and the driven gear to provide a mechanical link between the drive gear and the driven gear. It is contemplated that any type of gear may be used in a gearbox according to the present disclosure. Such gears include spur gears, bevel gears, worm gears, and the like.

[0075] Providing a gearbox can be advantageous because it allows for 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 for providing torque 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, or the like.

[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 mentioned with reference to the first embodiment, the braking device of the present disclosure is not necessarily limited to what is conventionally referred to as a brake. Instead, the term "braking device" should be interpreted as encompassing any device configured to prevent and / or limit rotation. As those skilled in the art will readily appreciate, a gearbox will always exhibit a certain degree of frictional resistance, which will provide a certain degree of braking force to the mechanical system engaged with the gearbox. This 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 with a gear train 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 rotation into high-torque rotation. This can be advantageous because it allows the rotatable multi-head scraper unit to be manually operated, for example, using a steering wheel or crank. Furthermore, 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 the unrestricted (i.e., forward) direction, the pawl easily slides upward and over the gently sloping edges of the teeth, and as the pawl passes the tip of each tooth, the spring forces the pawl into the recess between the teeth. However, when the teeth move in the opposite (rearward) direction, the pawl will catch on the steeply sloping edge of the first tooth it encounters, thereby locking it to the tooth and preventing any further movement in that direction.

[0083] The ratchet device can be advantageous because it serves to limit movement to only one direction of rotation, which allows for better control of the scraper device. The ratchet device can be configured to prevent rotation in a direction of rotation opposite to the direction of rotation 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 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 in both directions of rotation.

[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 can be advantageous as it will 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 scraper changes to be controlled remotely.

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

[0089] The rotational indexing capability can be advantageous because it facilitates the selection of a suitable operating position. For example, the rotational indexing capability can 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 can also be beneficial when adjusting the position of a scraper in operation without replacing the scraper. The multi-head scraper unit can 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 can 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 can be achieved by an integrated motion system. Such an integrated motion system typically includes a motor and a mechanical power transmission device as well as an encoder, a sensor, and a controller. Thus, the scraper assembly may further 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 assembly may further include at least one drive unit for rotating the rotatable multi-head scraper unit. The scraper assembly may further 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 squeegee unit, when viewed between a pair of adjacent squeegees of the two or more squeegees, has a radial extension that is at least 20 mm smaller than a minimum radial distance of the pair of adjacent squeegees.

[0092] In this context, the term "circumference of the rotatable multi-head squeegee unit" refers to the radial extension of the rotatable multi-head squeegee 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 become 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, as seen between a pair of adjacent scrapers, and the minimum radial distance between the pair of adjacent scrapers can vary with the roller diameter. The reason for this is that the crushing gap generally increases with the roller diameter, which results in an excess of thick, bulk 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 bulk material. Thus, for roller crushers with large crushing rollers, the difference defined above may have to be greater than 20 mm. The radial extension can be in the range of 20 mm to 150 mm less than the minimum radial distance between the pair of adjacent scrapers.

[0095] According to a second embodiment of the present disclosure, this and other objects are achieved in whole or in part 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, the roller crusher comprising: a flange attached to one of the two ends of one of the rollers, the flange extending in a radial direction of the roller and having an extension (E1) past the envelope surface of the roller. The roller crusher further comprises 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 material 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 in this position of the active scraper blades for an economically acceptable period of time before the scraper blades have worn to the point where the distance between the scraper blades and the outer surfaces of the rollers approaches the minimum gap between the rollers for crushing and the scraper blades must be repositioned or replaced. The minimum gap between the rollers is set by a travel stop 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 blade and the roller surface and / or 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 blade and the outer surface of the roller. Similarly, the minimum flange distance is defined as the minimum distance between the active blade and the inner surface of the flange.

[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, the roller having 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 for automatic determination of when worn scrapers need to be replaced. It is envisioned that this replacement operation could be performed while the roller crusher is in operation, thereby eliminating the need to shut down the roller crusher. Furthermore, the sensor system can allow for improved prediction of when the roller crusher must be shut down to replace a completely worn rotatable multi-scraper unit. For example, the sensor system can be configured to determine how many of the at least two scrapers are still usable 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 a 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 material, 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 scraping operation, the scraper blade is subject to wear. Consequently, 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 over 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 closer to the envelope surface, thereby compensating for the effects of wear on the radial extension of the scraper blade.

[0108] The scraper assembly may preferably include a rotational indexing capability for selectively rotating the rotatable multi-head scraper unit between predetermined angular positions. This rotational indexing capability may be advantageous because it facilitates selection of a suitable operating position. Specifically, the rotatable multi-head scraper unit may be rotated such that an operating scraper moves from a first operating position to a second operating position, each operating position having a different distance from the envelope surface. This rotational indexing capability may be used to define a plurality of predetermined operating positions for the operating scraper, 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 because it eliminates the need to manually change the scraper blades at the roll crusher. In addition to the benefit of reduced manual labor, it allows the scraper blade 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 for automatic determination of when a worn scraper blade 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 contemplated that such replacement or movement operations can be performed while the roller crusher is in operation, thereby eliminating the need to shut down the roller crusher. Furthermore, the sensor system can allow for improved prediction of when the roller crusher must be shut down to replace a completely worn rotatable multi-scraper unit. For example, the sensor system can be configured to determine how many of the at least two scrapers are still usable 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 appended claims and the drawings.Note that the present disclosure relates to all possible feature combinations.

[0115] In general, unless otherwise expressly defined herein, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field. Unless expressly stated otherwise, all references to "a / an / the [element, device, component, means, step, etc.]" should be interpreted as referring to at least one instance of the element, device, component, means, step, etc. Unless expressly 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 variations thereof 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 roller crusher according to an embodiment of the present disclosure.

[0123] Figure 3C is a top view of a portion of a roller 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 an 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 an 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] Figure 8A The carrier according to the embodiment of the present disclosure Figure 4 A partially cutaway perspective view of a scraper device capable of rotating a multi-head scraper unit.

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

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

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

[0132] Figure 10 is a schematic side view of a portion of a roller 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] Figure 11 is a schematic side view of a rotatable multi-head squeegee unit arranged in two different operating positions relative to a roller according to an embodiment of the present disclosure.

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

[0135] Figure 12B yes Figure 12A A three-dimensional view of a rotatable multi-head scraper unit of a scraper device.

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

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

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

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

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

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

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

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

[0144] Figure 14E is formed Figure 14A Exploded view of the scraper body and scraper support structure of a portion of a rotatable multi-head scraper unit.

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

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

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

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

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

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

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

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

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

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

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

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

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

[0158] Figure 20 yes Figure 19 An enlarged perspective view of one of the scraper devices.

[0159] Figure 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 presently preferred embodiments of the present disclosure are shown. However, the present disclosure may be embodied 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. Like reference numerals refer to like 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 is arranged at each end of one of the grinding rollers (such as Figure 2A and discussed further below), or by arranging a flange on each grinding roller (e.g. Figure 2BThe roller crusher is a roller crusher that is designed to maintain a crushing effect along the length of the rollers (as shown and discussed further below). However, during operation of the roller crusher, these flanges and the edges of the opposing rollers are subject to significant stress and wear due to the accumulation of ground material in the transition between the flanges and the envelope surface of the rollers. The prior art has proposed scraper elements for removing such material accumulations, but the present disclosure aims to provide a scraper arrangement that reduces maintenance time and simplifies the scraper position adjustment and replacement procedures.

[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 be selectively rotated 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 scraper replacement is required, 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. This roller crusher 1 comprises a frame 2, in which a first, stationary 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 a slidable manner in the frame 2. The bearings 6, 6' are movable in the frame 2 in a direction perpendicular to the longitudinal direction of the first and second crushing rollers 3, 4. Typically, guide structures 7, 7' are arranged along the upper and lower longitudinal frame elements 12, 12', 13, 13' of the roller crusher 1 on a first side 50 and a second side 50' of the frame. The bearings 6, 6' are arranged in movable bearing housings 8, 8', which are slidable 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 against the forces generated at the grinding rollers 3, 4 due to the feed of material into 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 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 FIG. Figure 3A ), and is positioned on the axial outside of the roller body of the opposite grinding roller 4.

[0166] Another prior art roller crusher is disclosed, for example, in WO 2013 / 156968, in which each grinding roller having a bearing is arranged in interconnected arched frame segments, wherein each interconnected arched frame segment is pivotally connected to a base frame. The subject matter disclosed in the present disclosure is equally applicable to this prior art roller crusher arrangement.

[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, as this will 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 pass through the crushing gap for crushing. 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 FIG. 1 has a flange 36 disposed on the second grinding roller 4' (rather than the first grinding roller 3'), meaning each grinding roller 3', 4', has a flange 36, 36'. As will be readily understood by those skilled in the art, the technical effect of preventing material from leaving the roller crusher 1, 1' at both ends of the gap is equally well achieved in both disclosed embodiments. Importantly, the disclosed utility model concepts are 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. 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 which are known in the prior art and 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 blocks 35, 35'. For some roller crushers and / or materials to be crushed, the minimum gap M can 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, larger minimum gaps are conceivable, 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 in the corners 40 between the envelope surface 37 of the grinding roller 3 and the inner surfaces 39 of the flanges 36, 36' (see FIG. Figure 3A ). Figure 3A The schematic diagram shows the Figure 1 and Figure 2A This material accumulation 41 of the roller crusher 1 is not present and is generally undesirable because it creates an increased local load in this area during operation, which can 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, means are provided for removing at least a portion of this material accumulation 41. The present disclosure relates to such means in the form of a scraper device 200 utilizing a mechanical scraper 100. First, reference will be made to Figures 3A to 3C Discussion of the mechanical scraper 100, and subsequent 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 arrangement 200 which will be described in detail later but is shown here separately with respect to the grinding rollers 3, 4 for the sake of clarity. The mechanical scraper 100 comprises two wear-resistant members 102a, 102b provided at one end of the scraper 100, thereby defining a scraping surface 104 which 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 a tangent to 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 Figure 3C As can be seen in Figure 3C As shown, the figure shows the 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 contributing to 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 carved recesses in the pile over time. This is particularly true in 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 reduces overall wear on the scraper 100 because the scraper experiences significantly less wear when 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 100 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 operated for an economically acceptable period of time before the scraper 100 has worn to the point where the distance between the scraper 100 and the outer surface 37 of the roller 3 approaches 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 surprising, as it is foreseeable that in order to completely avoid contact between the roller 4 and the material accumulation 41, the scraper 100 might miss material that must be removed. However, positioning the scraper 100 closer to the flange 36 presents other disadvantages. First, it increases the risk of damage to the scraper 100 by the flange 36 and / or the material accumulation 41 on the flange 36, a risk that increases with decreasing distance from any moving surface. Second, it increases the risk of damage to the flange 36 itself. By positioning the scraper 100 at a minimum flange distance S2 greater than the distance F, a reasonable compromise is achieved. A sufficient amount of material is removed from the accumulated material 41 at the flange 36 while maintaining the scraper 100 at a safe distance from the flange 36, resulting in extended scraper 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 it 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 flange 36 of the roller. Figures 4 to 21 , the scraper (eg 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 the 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 of the accumulated material 41 present at one end of the roller 3, while the other scrapers 100 are located at a position away from the envelope surface 37 of the roller and are therefore idle scrapers that do not perform any scraping. Therefore, at any point in time, only one scraper 100 of the scraping device 200 performs scraping. Now reference will be made to Figure 4 and Figure 5 Two different exemplary embodiments of rotatable multi-head squeegee 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 equidistantly spaced 120 degrees from each other. 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 previously mentioned, each scraper 100 comprises a scraper body 103 and two wear-resistant members 102a, 102b, which together have Figure 4 and Figure 5 The scraping surface 104 is represented by the dotted area in the figure. Each scraper 100 is releasably fixed to the star bracket 230' at a dedicated support structure 220 by bolting. The bolting allows for an easy assembly process when preparing the rotatable multi-head scraper unit 210' for installation 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 scraping operation, significant material will impact the rotatable multi-head scraper unit 210', and without the wear protection element 232', there is a risk of irreversible damage to the star bracket 230' even before all three scrapers 100 are in service. The rotatable multi-head scraper unit 210' is attached to a shaft member 240', which 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 when viewed between a pair of adjacent scrapers 100 of the two or more scrapers 100, which is at least 20 mm smaller than the minimum radial distance T between the pair of adjacent 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 become 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', as seen between a pair of adjacent scrapers 100, and the minimum radial distance T of the pair of adjacent scrapers 100, can vary with the roller diameter. This is because the crushing gap G generally increases with roller diameter, resulting in a greater accumulation of excess bulk material having a greater thickness 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 important to consider that the minimum difference defined above must exceed the thickness of the bulk material 41. Therefore, for a roller crusher 1 with a large crushing roller, the difference defined above may need to be greater than 20 mm. The radial extension can be in the range of 20 to 150 mm less than the minimum radial distance between the pair of adjacent scrapers 100.

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

[0181] Figure 5A rotatable multi-headed scraper unit 210 according to a second exemplary embodiment is shown. The rotatable multi-headed 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-headed scraper unit 210 at respective radial distances T from the axis of rotation A of the rotatable multi-headed 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, such that they are typically provided on one side of the rotatable multi-headed scraper unit 210, leaving no scraper on the other side of the rotatable multi-headed scraper unit 210. In other words, the rotatable multi-headed scraper unit 210 is asymmetrical. However, the scrapers 100a-100d and their associated support structure 220 can be arranged with 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 by scraper 100d, 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 provided 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 envisaged. 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 support 230 of the rotatable multi-head scraper unit 210 is also asymmetrical and has a periphery 248 on its scraper free side, which periphery 248 has a radially outward extension distance T a 、T b A rounded profile 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 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 positioned slightly closer to the axis of rotation A than scraper 100b, the minimum radial distance between the adjacent scrapers 100a, 100b will be the radial distance T a The advantages of the above features are usually related to Figure 4 The same as outlined in the first exemplary embodiment.

[0182] Providing an asymmetric rotatable multi-head scraper unit 210 with a star-shaped bracket 230 formed in this manner provides an alternative way to minimize the problem of wear damage. Instead of actively protecting the rotatable multi-head 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 hitting the scraper 100 that is idling and waiting to be used as a scraper in operation. The rotatable multi-head 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-head scraper unit 210. Such a releasable fastening device can be, for example, a flange connection 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 here. The shaft member 240 is rotatably attached to the support device 250, 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 roller crusher 1.

[0183] The advantage of the rotatable multiple scraper unit 210, 210' of the present disclosure is that it can provide active scrapers 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 multiple scraper unit 210, 210' can be arranged at different positions relative to the grinding roller 3 depending on the type of roller crusher 1. Figure 6 , which discloses that the rotatable multi-head scraper unit 210 ′ of the first exemplary embodiment is located at approximately 7 o'clock, ie, at the lower end of the roller 3, and Figure 7 , the rotatable multi-head scraper unit 210 of the second exemplary embodiment is shown located at approximately the 11 o'clock position, ie, 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 wear-resistant components 102a, 102b, which have a scraping surface 104 including polycrystalline diamond (PCD). The wear-resistant components 102a, 102b may also be referred to herein as scraping elements 102a, 102b. 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, Figure 8A and Figure 8B The scraper device 200' is equipped with Figure 4 The multi-head scraper unit 210' can be rotated, and in the second embodiment, Figure 9A and Figure 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 disposed, 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 Figure 8A and Figure 8B As shown, shaft member 240 is a stepped shaft. Shaft member 240 has a first shaft portion 243 connected to a first end 241 and a second shaft portion 244 connected to a second end 242. First shaft portion 243 has a first shaft diameter D1, and second shaft portion 244 has a second shaft diameter D2. First shaft diameter D1 is smaller than second shaft diameter D2, and shaft member 240 has an annular surface 245 that is substantially transverse to the axis of rotation A at the intersection between annular surface 245 and first shaft portion 243. The purpose of annular surface 245 will be described below.

[0188] The scraper arrangement 200', 200 further comprises a support arrangement 250 which is arranged to at least partially surround the shaft member 240 and is further arranged to be connected to the frame 2 of the roller crusher 1. The support arrangement 250 comprises a bracket 252 mounted on a mounting plate 258. The mounting plane 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. Figure 9A and Figure 9B ).exist Figure 9A and Figure 9B Also visible is a portion of a dust enclosure 62, within which the rotatable multi-head scraper unit 210 is disposed. However, as will be readily understood by those skilled in the art, the scraper assembly 200 is not supported by the dust enclosure 62. It extends through an opening 63 in the dust enclosure 62 but is otherwise fully supported by the frame 2.

[0189] The bracket 252 has through-holes 254 on opposing sides thereof, through which the shaft member 240 extends. The bracket 252 has an interior space within which a first brake device B1 is housed. The first brake device B1 is configured to prevent and / or limit rotation of the rotatable multi-head scraper unit 210 during scraping operation by applying radially inward pressure on the shaft member 240. The first brake device B1 includes a friction element 262 disposed around 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 made of an elastic material (e.g., rubber or polyurethane). The support element 264 surrounds the friction element 262 and is disposed within a support structure 253, which, in the exemplary embodiment, forms part of the bracket 252. The support structure 253 at least partially surrounds the support element 264, thereby spatially constraining the support element 264 radially outward and axially toward the gearbox 270. By fastening bracket cap 255 to bracket 252, support element 264 is externally compressed. This compression of support element 264 affects its elastic material, causing it to expand in other directions: axially toward gearbox 270 and radially outward and radially inward toward friction element 262. Because support structure 253 effectively prevents any expansion directed axially and radially outward, the end result is that support element 264 compresses friction element 262, which in turn exerts pressure on shaft member 240. As those skilled in the art will readily appreciate, this creates potential rotational resistance or damping in the mechanical system, thereby providing a first braking mechanism B1. Finally, bracket cap 255 includes a through-hole 256, the diameter of which is smaller than the diameter of the adjacent through-hole 254b of bracket 252. The diameter of through-hole 256 is selected to match the first shaft diameter D1 of first shaft portion 243, while through-holes 254a and 254b are selected to match the second shaft diameter d2 of second shaft portion 244. Importantly, the diameter of the through hole 256 is smaller than the second shaft diameter D2. This allows the bracket cap 255 to be used to retain the shaft member 240 within the support device 250 (and thus on the roller crusher) 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 arrangement 200 in the form of a rotational movement to enable the rotating multi-head scraper unit 210 to rotate when it is necessary to replace a worn scraper (e.g. the first scraper 100a in the queue) with a later 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 which may risk damaging the gear train 272. For the sake of clarity, Figure 8A Only part of the housing 271 is shown in FIG. Figure 9A and Figure 9B The housing 271 is also shown. The drive train (gear train) 272 includes a drive gear 273 attached to a drive shaft 277. The drive gear 273 engages 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. Figure 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 collectively referred to 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 be changed 90 degrees relative to the shaft member 240, which can be beneficial for some applications due to, for example, space limitations. Second, the worm drive provides a relatively large transmission ratio, which is also beneficial, as will be explained below.

[0191] The (overall) 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 allows a higher 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 manually steered (in the exemplary embodiment, via the steering wheel 279). However, the gearbox 270 of the scraper assembly 200 also has another function: it constitutes a braking device, referred to herein as the second braking device B2. As will be readily understood by those skilled in the art, any gearbox will provide some 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 increasing gear ratios (this is why we tend to use reverse or first gear after stopping, as reverse and first gear have the largest gear ratios). In other words, the gear ratio will affect the degree of braking force that the gearbox 270 can provide to rotate the multi-head scraper unit 210. Specifically, the braking force will increase as the gear ratio of the gear train 272 increases.

[0192] Turn again Figure 8A , Figure 8A To illustrate these features most clearly, the scraper arrangement 200', 200 may also include a third braking device B3 in the form of a ratchet arrangement 280. The ratchet arrangement 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 pivotally disposed in the gearbox 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 sloped edge of the first tooth 282 it encounters, thereby locking it to the tooth 282 and preventing any further movement in that direction.

[0193] Figure 10 FIG. 8 shows a sensor system 80 for a roller crusher 1 for use with a scraper assembly 400 according to an exemplary embodiment of the present disclosure. The scraper assembly 400 is similar to Figure 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 status of the scraper device 400, and a control unit 50 operatively connected to the sensor system 80 and the drive unit 70. Figure 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 worn scrapers 100 need to be replaced. It is conceivable that such a replacement operation is available during the operation of the roller crusher 1, thereby eliminating the need to shut down the roller crusher. In addition, the sensor system 80 can allow for improved prediction of 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 can be configured to determine how many of the at least two scrapers 100 are still available for scraping.

[0194] Finally, refer to Figure 11 Describe in detail one embodiment of the scraper device disclosed herein, Figure 11 Shown Figure 4 rotatable multi-head scraper unit 210' and 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 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 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 Figure 11The scraper 100 shown in FIG. 1 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 axis of rotation 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 effects of wear on the radial extension T of the scraper 100.

[0196] This is Figure 11 In the figure, two different operating positions P1 and P2 are shown. 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 placed at a distance H1 from the envelope surface 37 of the roller 3. Figure 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 dotted outline). When the scraper 100 has been partially worn during operation (not shown), the rotatable multi-head scraper unit 210' can selectively rotate by an angle B to a second operating position P2, at which position the scraper 100 is instead 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 an unworn scraper 100. It will be readily understood by those skilled in the art 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, also in the second operating position P2.

[0197] Figure 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. Figure 12B The rotatable multi-head scraper unit 510 shown separately in FIG 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 apart from each other. In other words, for this non-limiting exemplary embodiment, the rotatable multi-head scraper unit 510 is symmetrical. Figure 12A and Figure 13BAs shown, the periphery 548 of the rotatable multi-head scraper unit 510 has a radial extension K when viewed between a pair of adjacent scrapers 501 of the two or more scrapers 501, which is at least 20 mm smaller than the minimum radial distance T between the pair of adjacent scrapers 501. Figure 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 Figure 12A The radial distance T defined in FIG. 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, clamping, etc. 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 comprises a rotary actuator 580 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 Figure 12A The rotary actuator 580 may be, for example, the one previously described with reference to Figure 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 further includes at least one braking device 570 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 plurality of scrapers 501 are in operation. Figure 12A The at least one braking device 570 may be similar to that previously described with reference to Figure 8A The at least one braking device B1 , B2, B3 is described, but may also be different. Alternative embodiments of the at least one braking device 570 will be described later.

[0199] like Figure 12A As shown, a rotatable multi-head scraper unit 510 is disposed at a first end 512 of the scraper assembly 500, and a rotary actuator 580 is disposed at an opposite second end 514 of the scraper assembly 500. The rotatable multi-head scraper unit 510 extends in a reference plane RP that is orthogonal to the axis of rotation A. As will be apparent upon reviewing the accompanying drawings, the reference plane RP is shown at different axial positions in different drawings. This is done to facilitate understanding of the scraper geometry. However, the reference plane RP is always orthogonal to the axis of rotation A.

[0200] like 12A to 12CAs shown, the star-shaped 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. Releasable attachment can be achieved by bolting the elements together with fastening bolts 518 that enter through holes 513 and are fixed in threaded holes 508. The fastening bolts 518 are fixed in the threaded holes 508. Figure 12A Not visible in , but in Figure 19 As can be seen, Figure 19 Shown is the installation Figure 12C Another exemplary embodiment of a rotatable multi-scraper unit on the main support structure 509. Figure 12A As shown, the ring has an annular joint portion 511. The purpose of providing two or more scraper support structures 520 is to allow them to be replaced individually in the field without having to completely disassemble the scraper assembly 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 structures 520 have 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 joint portion 511.

[0201] Each scraper 501 includes a scraper body 503 and a scraping element 502. The scraping element 502 has a Figure 12A and Figure 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 comprising polycrystalline diamond (PCD).

[0202] As those skilled in the art will readily appreciate, diamond can be a single, continuous crystal, or it can be composed of many smaller crystals (polycrystals). Large, clear, and transparent single-crystal diamonds are commonly used as gemstones. Polycrystalline diamond (PCD) is composed of countless small particles that are easily visible to the naked eye due to 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 blade 501 can be significantly extended. Typically, such a scraping surface 504 would 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) can extend the wear life by up to about 50 times compared to a composite material comprising, for example, tungsten carbide alone.

[0206] The scraping element may comprise 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 comprise 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 grit 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 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. Once the diamond particles have been sintered and compacted to form scraped-off polycrystalline diamond (PCD), image analysis using a scanning electron microscope is used to determine the final microstructure particle size distribution, i.e., the diamond particle size of the scraped-off polycrystalline diamond (PCD).

[0209] In addition to the scraper element 502, each scraper 501 of the scraper assembly 500 also includes a scraper element 505 on a surface 506 facing the rotary actuator 580, the surface 506 comprising 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 can have different properties than 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 thus may be mostly exposed to material impact, while the scraper element 505 will be oriented so that the material will impact at a certain angle, making 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 at least partially faces a 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 understood by a person skilled in the art, this achieves the following effect, namely, when the scraper device 500 is arranged on the roller crusher 1, the active scraper (i.e. Figure 12A The scraping surface 504 of the scraper 501A in FIG. 1 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 a star bracket 530 at the scraper support structure 520 by means of a bolted connection. The bolted connection allows for an easy assembly process when preparing the rotatable multiple scraper unit 510 for installation on the roller crusher 1. The rotatable multiple scraper unit 510 is attached to a shaft member 540, which is rotatably attached to a 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 Figure 13A Best shown in Figure 13A Showing each scraper 501 of the scraper arrangement 500 in more detail, the surface 506 facing the rotary actuator 580 has an extension E2 tangentially from the scraper element 502 towards its rear end 507. The scraper 501 is constructed and arranged such 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 Figure 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, Figure 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 expressed as 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 Figure 13A Shown in.

[0213] like Figure 13A and Figure 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 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 arranged tangentially around the rotatable multi-head scraper unit 510, these tangential planes TPS are angled relative to each other.

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

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

[0216] like Figure 12A and in more detail as Figure 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. Figure 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 arrangement 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 either side thereof. One advantage of this is that when the scraper arrangement 500 is arranged and operated on the roller crusher 1, the material to be removed, once it has 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 arrangement according to the present disclosure can be implemented in many different ways. In the following, reference will be made to Figures 14A to 17C Detailed description of various alternative embodiments of the scraper assembly. 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 Figure 12C The main support structure 509 is shown. Providing the same interface for different squeegee assembly types allows for varying the number of squeegees on a rotatable multi-head squeegee unit as well as the structure and characteristics of the individual squeegees attached to the squeegee support structure.

[0217] Figures 14A to 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 scraper support structure 520 described above in that it has the same interface for attaching 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 to 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. Figure 14B ). For the exemplary embodiment, the radial distance T is the same for all eight scrapers 601, so the minimum radial distance will be Figure 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 is Figure 14E As best shown in Figure 14E As shown, the geometric locking engagement is at least partially defined by a protruding structure 660 of the scraper 601 being 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 a 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. Figure 14E ).

[0219] Furthermore, the scraper 601 is structurally different from the scraper 501. In particular, the scraping surface 604 is not oriented in the same manner. The scraping surface 604 is arranged to be inclined relative to the normal N to the reference plane RP, as defined in front of the scraping surface 604, and is inclined so that the distance L1 between the normal N and the scraping surface is toward the rotary actuator 580 (i.e., it is pointing toward the rotary actuator 580). Figure 14C See Figure 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 example embodiments, 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 within a tangential plane TPS of the scraper 601 that is orthogonal to the reference plane RP. Figure 14A and Figure 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 further comprises a scraper element 605 on one side thereof. The scraper element 605 comprises a surface 606 comprising polycrystalline diamond (PCD). The scraper 601 is constructed and arranged such that the surface 606 forms an angle β between the surface 606 facing the rotary actuator 580 and a reference plane RP, wherein the angle β is defined in a tangential plane TPS of the scraper 601 which 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 Figure 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. While the ranges disclosed above are currently preferred, it is contemplated that the axial extension X may be greater than 75 mm. The axial extension may depend on, among other things, the roller crusher 1, the operating conditions, and the material to be crushed. 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 and 4, and the size of the accumulated material 41 to be removed. Larger material accumulations 41 may require a larger axial extension X.

[0222] Figures 15A to 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 will therefore only be briefly described here. Like reference numerals refer to like elements and have already been described earlier in this document. The scraper assembly 700 comprises 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. angle β=0 (see Figure 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. Figure 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. Figures 15A to 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. Figure 15B ). For the exemplary embodiment, the radial distance T is the same for all eight scrapers 701, so the minimum radial distance will be Figure 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] 16A to 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 will therefore only be briefly described here. Like reference numerals refer to like elements and have already 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 the protrusion 815 to be provided with a considerable axial extension X. 16A to 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 Figures 15A to 15C 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 Figure 16B ). For the exemplary embodiment, the radial distance T is the same for all eight scrapers 801, so the minimum radial distance will be Figure 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] 17A to 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 will therefore only be 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 arrangement is mounted on a roller crusher, the surface 919 will face away from the flange 36. Therefore, as will be readily understood by those skilled in the art, the surface 919 will also face away from the rotary actuator 580 (see Figure 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 tangentially from its scraping element 602 towards its rear end 907, wherein the scraper 901 is constructed and arranged such that the distance L3 between the surface 919 facing away from the rotary actuator 580 and the rotary actuator 580 decreases towards the scraping element 902 over at least a portion of the extension E3. As will be readily 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, "surface" should therefore be interpreted as a mathematical or geometrical surface. This is in Figure 17A , where the distance L3 is marked as a solid line outside the scraper 901 and as a dashed 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 tangential 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 tangential plane TPS are Figure 17A and Figure 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. Figure 17B). For the exemplary embodiment, the radial distance T is the same for all eight scrapers 901, so the minimum radial distance will be Figure 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 FIG.

[0227] Figure 18A and Figure 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 support 1030 arranged to be mounted on a shaft, such as the shaft 240, 540 of the exemplary embodiments of scraper devices disclosed previously. The rotatable multi-head scraper unit 1010 differs from the aforementioned 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. The arrangement of ceramic inserts on these surfaces 1006, 1019 increases 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. Figure 18A ). For the exemplary embodiment, the radial distance T is the same for all ten scrapers 1001, so the minimum radial distance will be Figure 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 FIG.

[0228] Figure 19 The complete assembly of two scraper assemblies 1100 and 1100' according to the present disclosure is shown when arranged on the frame 1200 of the roller crusher 1. The scraper assemblies 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 assemblies 1000 and 1000' being arranged in a mirror-image manner.

[0229] Figure 20The scraper arrangement 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 Figure 12C ). The scraper support structure 620 is covered by wear-resistant covers 1190a, 1190b, which will be referred to later. Figure 21 Further description. Figure 20 In FIG. 6 , 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. 6 ). Figure 20 ). For the exemplary embodiment, the radial distance T is the same for all eight scrapers 1101, so the minimum radial distance will be Figure 20 The advantages of the above features are generally related to Figure 4 The same as outlined in the first exemplary embodiment.

[0230] The scraper elements 1102 differ from 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 positioned upstream of the rear portion 1104b so that the front portion 1104a will first encounter material to be removed from the roller 3. When the scraper arrangement 1100 is deployed on the roller crusher 1, the front portion 1104a will be positioned closer to the flange 36 than the rear portion 1104b. This can be advantageous because it allows the front portion 1104a to generate a very strong impact force on the localized area of ​​material accumulated on the roller 3 with the flange 36, thereby increasing the likelihood of breaking off a larger portion of the material. The rear portion 1104b can then intervene and help remove further material from the roller 3 and / or transfer already removed material away from the flange 36. The front portion 1104a may comprise polycrystalline diamond (PCD). The rear portion 1104b may also include polycrystalline diamond (PCD). Figure 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. Figure 20 ). For the exemplary embodiment, the angle γ is 45°.

[0231] from Figure 20 As can be seen in the figure, another difference between the scraper assembly 1100 and the previously described exemplary embodiments of scraper assemblies is the difference in the rotary actuator 1180 and the brake assembly 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 a limiter 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 and second structures 1181 and 1183. Bolts 1185 and limiters 1186 can be received in at least some of the through-holes 1182 and 1184 to define specific angular positions for the rotatable multi-head scraper unit 1110 of the scraper assembly 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 is positioned to function as a functional scraper. Manual rotation can be achieved using a wrench tool (not shown) 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 for easier access to the first structure 1181 with a wrench tool. To more easily find an angular position where the through-holes 1182 and 1184 overlap, a retainer 1186 can be inserted into one of the through-holes 1182 of the first structure 1181. Abutment surface 11187 is defined on frame 1200 so that when retainer 1186 abuts abutment surface 1201, a proper overlap between through-holes 1182, 1184 is achieved. After the proper angular position is achieved, bolt 185 is inserted into one or more overlapping through-holes 1182, 1184 to secure first structure 1181 to second structure 1183, thus concluding the actuation process. Alternatively, a hydraulic cylinder or any other suitable means may be used. The above method is for illustrative purposes only. Those skilled in the art will appreciate alternative methods for achieving the described manual rotation.

[0232] As will be readily understood by those 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-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 and second sets of through-holes 1182 and 1184. Therefore, the locking device 1170 is releasable.

[0233] Figure 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 along their periphery. These openings 1191 are structures that allow the scrapers 1101 to protrude through the wear-resistant covers 1190a, 1190b (see Figure 20 ). An edge wall 1192 is provided between each of these openings 1191. These edge walls 1192 may protrude radially and axially, such as Figure 21As best shown. The wear shields of the first set of wear shields 1190a may also have screws 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 assembly 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 interior portion of the rotatable multi-head scraper unit 1110 around its periphery. The second set of wear shields 1190b also includes through-holes 1196 that are geometrically aligned to allow for receipt 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 aligned access openings 1197 such that they allow entry of the fastening bolts 118, as shown. Figure 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 Figure 14A and Figure 15B ) and the through hole 519 of the main support structure 508 (see Figure 12C ) is achieved in the main support structure 509. 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 wear cover 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, a tightening 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, many modifications and variations are possible within the scope of the appended claims. Furthermore, 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] Example 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 multi-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] wherein 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 such 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 assembly according to embodiment 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.

[0242] Embodiment 3. The scraper assembly 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] Example 4. A scraper device according to any one of Examples 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 squeegee assembly of 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 the 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 squeegee assembly of embodiment 11, wherein each scraping surface of the at least two squeegees extends in a plane having a normal that forms an acute angle with the squeegee axis along a reference direction.

[0252] Embodiment 13. A scraper assembly 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 squeegee device of any one of embodiments 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.

[0254] Example 15. A scraper device according to Example 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 forming a circular ring, and the circular ring has an annular joint portion.

[0255] Embodiment 16. The scraper assembly of embodiment 14 or 15, wherein each of the at least two scrapers is releasably arranged in the annular engagement portion by 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 assembly of embodiment 17, wherein the associated recess of the annular engagement portion is defined on a side surface thereof.

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

[0259] Embodiment 20. The squeegee assembly of any one of embodiments 1 to 19, further comprising a wear-resistant cover constructed and arranged to protect at least portions of the rotatable multi-head squeegee 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. The scraper device according to any one of embodiments 1 to 21, wherein the at least one braking device includes 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.

[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 arrangement 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 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 arrangement according to embodiment 1 is arranged at each end of the one flanged roller.

[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, characterized in that: The scraper device comprises: 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-head squeegee unit to allow operative use of one of the at least two squeegees at a time; and at least one braking device capable of preventing and / or limiting the rotation of said rotatable multi-head scraper unit during operation of one of said at least two scrapers, wherein 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 oriented along a reference rotation direction of the rotatable multi-head scraper unit.

2. The scraper device according to claim 1, characterized in that The scraper element further comprises a wear-resistant material, and the polycrystalline diamond (PCD) is at least partially embedded in the wear-resistant material.

3. The scraper device according to claim 2, characterized in that 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, characterized in that 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, wherein the rotatable multi-head squeegee unit extends in a reference plane orthogonal to the rotation axis.

5. The scraper device according to claim 4, characterized in that 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. The scraper device according to claim 4, characterized in that Each scraping surface of the at least two scrapers is arranged to be inclined relative to a normal to the reference plane defined in front of the scraping surface and to be inclined such that a distance between the normal and the scraping surface decreases towards the rotary actuator.

7. The scraper device according to claim 4, characterized in that 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 towards 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 towards the scraping element over at least a portion of the extension.

8. The scraper device according to claim 4, characterized in that 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 towards its rear end, wherein the scrapers are 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.

9. The scraper device according to any one of claims 1 to 3, characterized in that: 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.

10. The scraper device according to claim 9, characterized in that 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. The scraper device according to claim 4, characterized in that Each of the at least two scrapers extends in the reference plane along a scraper axis toward the scraper element, and wherein the scraper axis forms a first acute angle along the reference rotation direction with a radial axis of the rotatable multi-head scraper unit, which intersects the scraper element.

12. The scraper device according to claim 11, characterized in that 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 device according to claim 4, characterized in that 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 scraper device according to any one of claims 1 to 3, characterized in that: 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, characterized in that 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 circular ring sectors, the circular ring sectors together forming a circular ring, and the circular ring has an annular joint portion.

16. The scraper device according to claim 14, characterized in that Each of the at least two scrapers is releasably arranged in the annular engagement portion by means of a geometric locking engagement.

17. The scraper device according to claim 16, characterized in that 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.

18. The scraper device according to claim 17, characterized in that The associated recess of the annular engaging portion is defined on a side surface thereof.

19. The scraper device according to claim 17, characterized in that Each of the at least two scrapers comprises a scraper body, and wherein the protruding structure forms a part of the scraper body.

20. The scraper device according to any one of claims 1 to 3, characterized in that: The scraper assembly further includes a wear-resistant cover constructed and arranged to protect at least portions of the rotatable multi-head scraper unit.

21. The scraper device according to any one of claims 1 to 3, characterized in that 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 scraper device according to any one of claims 1 to 3, characterized in that The at least one braking device comprises a locking device capable of selectively locking the rotation of the rotatable multi-head squeegee unit during operation of one of the at least two squeegees.

23. The scraper device according to any one of claims 1 to 3, characterized in that The squeegee assembly has a rotational indexing capability for selectively rotating the rotatable multi-head squeegee unit between predetermined angular positions.

24. The scraper device according to any one of claims 1 to 3, characterized in that The periphery of the rotatable multi-head scraper unit, viewed between a pair of adjacent scrapers of the two or more scrapers, has a radial extension that is at least 20 mm smaller than a 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, characterized in that The roller crusher comprises: 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 roller, The roller crusher further comprises a scraper arrangement 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 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. The roller crusher according to claim 25, characterized in that 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 one flanged roller.

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