Double-shaft crusher with horizontal maintenance concept

Abstract

The present invention relates to a two-shaft grinder (1) for grinding solids or solids in liquids, wherein the grinder (1) comprises a grinder housing (2), a first cutting disc unit (14), and a second cutting disc unit (16). The first cutting disc unit (14) has a first bearing unit (80) having a first bearing housing (81) at a first axial end and a second bearing unit (82) having a second bearing housing (83) at a second axial end, and a first cutting disc block (40) is rotatably mounted about a first rotation axis (A1). The second cutting disc unit (16) has a third bearing unit (84) having a third bearing housing (85) at a first axial end and a fourth bearing unit (86) having a fourth bearing housing (87) at a second axial end, and a second cutting disc block (42) is rotatably mounted about a second rotation axis (A2). The grinder housing (2) has a first maintenance hatch cover (50), and the first maintenance hatch cover (50) may have a release position (P21) and a closed position (P11), and at the release position (P21), the first cutting disk unit (14) is allowed to be removed together with the first and second bearing units (80, 82).

Description

Technology Field

[0001] The present invention relates to a two-shaft grinder for grinding a solid in a solid or liquid, the grinder comprising: a grinder housing defining an internal grinding space; an inlet opening in the grinder housing for supplying a solid to the grinder housing; an outlet opening in the grinder housing substantially opposite the inlet opening for discharging a ground solid from the grinding space; a first cutting disc unit comprising a first cutting disc block having a plurality of first cutting discs disposed on a first hub body such that a space is provided between each of two adjacent first cutting discs; and a second cutting disc unit comprising a second cutting disc block having a plurality of second cutting discs disposed on a second hub body such that a space is provided between each of two adjacent second cutting discs, wherein the first and second cutting disc blocks have their rotation axes offset from each other axially such that at least some of the first cutting discs engage with the space between two adjacent second cutting discs and some of the second cutting discs engage with the space between two adjacent first cutting discs. Background Technology

[0002] Two-shaft or twin-shaft shredders of this design are used to shred solids, such as organic materials like animal carcasses, branches, twigs, and plants, or other materials generally such as plastic waste or recycled materials. The solids to be shredded can be fed into the two-shaft shredder through an inlet opening in a dry form or as a liquid stream.

[0003] For the purpose of effective grinding, a 2-shaft grinder has 2 shafts, and a plurality of cutting discs are disposed on each shaft and are referred to as cutting disc blocks. The cutting discs are reciprocally engaged with each other, and this advantage is made possible and achieved by the fact that between two adjacent cutting discs of one cutting disc block, there is an axial distance greater than the thickness of the cutting disc of the other cutting disc block, and the axial distance from each other of the two cutting disc blocks is smaller than the diameter of the cutting discs.

[0004] The two cutting disc blocks of a 2-shaft grinder are typically driven in opposite directions and are coupled to each other, for example, via a corresponding gearbox. Excellent grinding results are achieved particularly when the two cutting disc blocks rotate at different speeds. In this way, high shear and tearing forces are generated by the cutting discs rotating in opposite directions in the space between the two cutting disc blocks, ultimately leading to the effective grinding of solids. Furthermore, the different rotational speeds cause the different cutting segments of adjacent cutting discs to interlock with each other through their respective rotations, so that the cutting discs automatically clean the attached grinding material.

[0005] A disadvantage of this 2-shaft grinder design is that, due to the type of relative movement of the 2-shafts on which the cutting discs are positioned, a hard solid body may enter the grinding chamber and get caught between the two cutting discs or between the cutting discs and the opposite shaft, potentially causing damage. This can severely damage the cutting discs in the area of ​​their cutting edges, rendering further operation of the 2-shaft grinder impossible or resulting in only low grinding efficiency. Similarly, wear may occur on the cutting discs depending on the type and amount of material to be ground.

[0006] For this reason, it is known that a quick-change system is equipped on a 2-shaft grinder to remove the blade from the shaft in order to replace such a damaged blade. This ensures that the function of the 2-shaft grinder can be restored with minimal maintenance effort.

[0007] Another system known from WO 2018 087 398 uses a monolithic cutting disc block in which individual blades are integrally connected to a shaft or hub. A shaft journal is inserted into the axial end, so that the entire cutting disc block can be easily and quickly replaced.

[0008] The monolithic cut disk block is known from DE 20 2010 010 662U1.

[0009] A two-shaft grinder with a quick-change device is known from EP 3 248 687. Here, two cutting shafts each have an axial recess on one side and a shaft journal on the other side, so that these shafts can be removed through an inlet opening after a specific section is loosened. In particular, the entire engine block is removed from the section. This requires considerable effort, especially since the infeed funnel, etc., must also be removed to replace the cutting shafts.

[0010] DE 20 2012 007 418U1 discloses a grinding device in which individual blades can be replaced via a lateral flap that can be opened around a vertical axis in a door-like manner. To this end, the blades are positioned on a shaft so that they can be easily replaced. However, rotary blades are not provided. Accordingly, this concept cannot be applied to a cutting disc shaft or a cutting disc block as previously described.

[0011] Another two-shaft grinder is known from US 5,580,009B1. The two-shaft grinder disclosed herein is driven by a motor and a gearbox, and two cutting shafts rotate in opposite directions at a fixed speed ratio. The shafts are connected to their respective bearings or drive units via shaft connectors, and the shaft connectors can be detached. On the side of the grinder housing, wall elements can be removed to allow the cutting shafts to be replaced. Here, the disadvantage is particularly the shaft connection, and the advantage entails certain strength disadvantages.

[0012] Furthermore, EP 2 846 918B1 discloses a maintenance-friendly two-shaft grinder in which the hopper can be opened along with part of the cutting shaft bearing so that the cutting shaft can be accessed from above. The cutting shaft can then be released by removing a special bearing plate from the housing. The cutting shaft can then be removed upward and replaced with a new or different cutting shaft. The feed hopper and bearing housing are then closed again. A disadvantage of this is that the feed hopper must rotate far. For this reason, the two-shaft grinder disclosed in this document is not suitable for installations where, for example, a pipeline is provided instead of the feed hopper, or for two-shaft grinders where the feed hopper is fixed in some other way and cannot be easily removed.

[0013] Other 2-shaft grinders are known, for example, from EP 3 566 777 A1, DE 10 2007 049 028 A1, US 2014 0103152 A1, EP 2 662 143 A2, DE 4 315 671 A1, EP 3 453 460 A1 and EP 2 736 645 A1. The problem to be solved

[0014] The object of the present invention is to provide a two-shaft grinder of the aforementioned type that is improved with respect to maintenance and / or wear and service life. In particular, the grinder should be user-friendly, save maintenance time, and preferably prevent errors. means of solving the problem

[0015] In a first aspect, the present object is solved by a two-shaft grinder having the characteristics of claim 1. Accordingly, the two-shaft grinder is characterized in that a first cutting disc unit has a first bearing unit having a first bearing housing at a first axial end and a second bearing unit having a second bearing housing at a second axial end, and a first cutting disc block is rotatably mounted about a first rotation axis. A second cutting disc assembly has a third bearing unit having a third bearing housing at a first axial end and a fourth bearing unit having a fourth bearing housing at a second axial end, and a second cutting disc block is rotatably mounted about a second rotation axis. According to the present invention, the grinder housing further comprises a first maintenance hatch cover, the first maintenance hatch cover may have a release position and a closed position, and in the release position, allows for the removal of the first cutting disc unit together with the first and second bearing units.

[0016] According to this first aspect, the present invention is based on two main results: First, the inventors recognized that it is advantageous to provide a cutting disc unit as a structural unit comprising a cutting disc block and two bearing units—which can be removed from the device as a whole. In this way, the problems associated with the bearings of the cutting disc block can be avoided. Each of these bearing units has a bearing housing—which can be connected to and attached to the grinder housing. Therefore, when replacing or exchanging the cutting disc block, it is not necessary to disassemble the bearings of the cutting disc block as well. Rather, the bearings are removed immediately and are completely removed together with the disc block. This also makes maintenance of the bearings themselves easier. In prior art solutions for such purposes, such as the detachable shaft described in the background art, the bearings remain in the grinder housing, and only the shaft is replaced along with the knife. This subsequently makes maintenance of the bearings more difficult and again entails the almost complete disassembly of the entire two-shaft grinder. To avoid this, according to the present invention, it is proposed to remove the first and second bearing housings together with the cutting disc block.

[0017] A second basic idea of ​​the present invention is that a first maintenance hatch cover is provided to allow the cutting disc unit to be removed. Accordingly, it is not necessary to remove the first cutting disc unit by, for example, removing a supply hopper or removing a pipe from the discharge opening. Rather, the first maintenance hatch cover provides access to the grinder housing so that the first cutting disc unit can be removed.

[0018] The first and second cutting disc units are known from DE 20 2010 010 662U1, specifically as monolithic cutting disc blocks. In this case, the cutting discs are formed integrally with their respective hub bodies. The term “hub body” is therefore understood in the context of this disclosure not strictly as a shaft / hub connection, but rather defines an internal region for the cutting discs. However, the cutting disc units may also be formed from shafts to which individual blades are detachably attached, as is known in the prior art. Mixed forms or other designs may also be conceived and preferred. Particularly preferred, however, is a monolithic cutting disc block in which shaft journals are provided directly to each internal shaft, and these internal shafts are then accommodated in the first and second bearing units. In this embodiment, the monolithic cutting disc block and the internal shafts are formed integrally and manufactured as a semi-finished product. This provides particularly high rigidity and simplifies the manufacture of the cutting disc blocks.

[0019] According to the present invention, the first maintenance hatch cover may remove only the first cutting disc unit. That is, when the maintenance hatch cover moves from the closed position to the release position, only the first cutting disc unit may be removed. However, the first maintenance hatch cover may also allow the second cutting disc unit to be removed. In the release position of the first maintenance hatch cover, this may remove the first cutting disc unit and the second cutting disc unit. In this way, particularly simple and comprehensive maintenance can be achieved.

[0020] In a first preferred embodiment, however, the grinder housing has a second maintenance hatch cover, the second maintenance hatch cover may have a release position and a closed position, and in the release position, allows for the removal of the second cutting disc unit together with the third and fourth bearing units. Accordingly, preferably, only the first cutting disc unit can be removed through the first maintenance hatch cover, and only the second cutting disc unit can be removed through the second maintenance hatch cover. To remove the first cutting disc unit, the first maintenance hatch cover must therefore be brought from the closed position to the release position, and to remove the second cutting disc unit, the second maintenance hatch cover must be brought from the closed position to the release position. Each cutting disc unit is accordingly assigned its own maintenance hatch cover. This means that only the maintenance hatch cover associated with the cutting disc unit must be opened. For example, if two cutting disc units are accessible through a single maintenance hatch cover, the cutting disc unit in front of the hatch cover must be removed to service the rear cutting disc shaft.

[0021] Preferably, the bearing unit includes first, second, third, and fourth bearing units to seal the bearings of the bearing unit against the cutting disc block. The bearings of the bearing unit—usually ball bearings, roller bearings, etc.—must be protected against water ingress from the grinding chamber into the bearings. For this purpose, a seal is provided. The seal is also part of the bearing unit and is housed inside each bearing housing. That is, the seal can be removed from the grinder housing along with the cutting disc unit when the cutting disc unit is removed, and can also be replaced or serviced. Furthermore, there is no risk of damaging the corresponding seal when the cutting disc block is simply removed from the grinder housing. This advantage improves the maintenance and service life of the 2-shaft grinder. The bearing housing, together with the bearing and seal positioned at the end of the cutting disc block, forms an integral bearing and seal concept, which allows for particularly easy maintenance.

[0022] In the assembled state, each bearing housing of the bearing unit can preferably be secured to the grinder housing against rotation. In this way, the bearing unit also serves to secure the cutting disc unit to the grinder housing. For example, the bearing unit can be fastened to the grinder housing by screw and / or clamp connections.

[0023] The grinder housing preferably has an inlet side having an inlet opening, an outlet side having an outlet opening, and first and second end sides positioned perpendicular to the first and second rotation axes. Additionally, the grinder housing preferably includes first and second transverse sides. Accordingly, the grinder housing is preferably formed in a substantially rectangular shape. Preferably, a first maintenance hatch cover is positioned on the first transverse side, and a second maintenance hatch cover is positioned on the second transverse side. In this way, it is particularly evident that other attachments on the grinder housing, such as peripheral devices on the inlet opening, peripheral devices on the outlet opening, or peripheral devices on the end faces, do not need to be removed or disassembled to remove the first and second cutting disc units from the grinder housing. This advantage greatly simplifies maintenance. It has been found that 2-shaft grinders, when installed in a plant, often have peripheral equipment or attachments on both the inlet and outlet sides that cannot be easily removed. By positioning maintenance hatch covers on the transverse sides, particularly easy maintenance is achieved. Preferably, the grinder housing is oriented so that the rotation axes of the first and second cutting disc units are aligned horizontally. The first and second cutting disc units can then be removed perpendicular to their rotation axes but parallel to the plane formed by the two rotation axes. This advantage is again particularly easy, as, for this purpose, a lift truck, etc., can be provided so that the cutting disc units can be removed from the grinder housing and the cutting disc units can be serviced.

[0024] In a preferred embodiment, the first cutting disc unit is positively fastened to the grinder housing by the first and second counter holders. Correspondingly, the second cutting disc unit is positively fastened to the grinder housing by the third and fourth counter holders. The first and second or third and fourth counter holders may be fastened to the grinder housing, for example, such that the corresponding bearing housings are frictionally held between the counter holders and the grinder housing, respectively. The counter holders, on the one hand, serve to provide sufficient stability to the first and second cutting disc units, while simultaneously acting as an anti-loss device when the first and second maintenance hatch covers are in the release position. In this embodiment, the first and second maintenance hatch covers do not intend to absorb force or support or hold the first and second cutting disc units against the grinder housing. Lateral forces and moments may be supported by the first, second, third, and fourth mating retainers and also by bolt connections additionally provided between the respective bearing housings and the grinder housing.

[0025] Preferably, the first and second counter holders are covered by the first maintenance hatch cover when the hatch cover is in the closed position. In the release position of the first maintenance hatch cover, the first and second mating holders are preferably released. In this way, on the one hand, the fastening elements of the mating holders can be protected, and on the other hand, the loosening of the first and second mating holders is prevented when the first maintenance hatch cover is in the closed position. Preferably, the same applies to the second maintenance hatch cover. Accordingly, the second maintenance hatch cover covers the third and fourth counter holders when it is preferably in the closed position. When the second maintenance hatch cover is in the release position, the third and fourth mating supports are preferably released.

[0026] A first kinematic system may be provided to move the first maintenance hatch cover from a closed position to a release position and vice versa. The kinematic system may, for example, allow the first maintenance hatch cover to be raised without rotating about its own axis. Such a kinematic system is very suitable for moving this maintenance hatch cover from a closed position to a release position. In the prior art, a concept is known in which the maintenance hatch cover rotates about the hinge of the door. In this case, however, it is not possible to also provide a scraper on the maintenance hatch cover. By means of the kinematic system, the maintenance hatch cover may be raised relative to the grinder housing so that the scraper can be attached to the maintenance hatch cover without any problems, because the scraper moves only parallel to the cutting disc even when the maintenance hatch cover is opened. At the same time, the maintenance hatch cover is opened to a wide area that is very easily accessible in the release position. Preferably, the same applies again to a second maintenance hatch cover to which a second kinematic system may be provided. The first and second kinematic systems are preferably identical.

[0027] Furthermore, preferably, a first lifting device acts on the first parallel motion system to move the first maintenance hatch cover from a closed position to a release position. The first lifting device is preferably designed as a hydraulic device, a pneumatic device, a spindle actuator, or an electromagnetic actuator. Preferably, the lifting device can control a force, i.e., a supporting force, so that an operator can more easily bring the first maintenance hatch cover to the release position. Preferably, a second lifting device is again applied in the same way to the second maintenance hatch cover, which is preferably provided.

[0028] Preferably, at least one of the first and second cutting disc blocks, preferably both, are each provided with at least one first groove. The first groove is preferably designed as a circumferential groove and extends circumferentially around the axis of rotation of each cutting disc block. The first groove is preferably provided between two adjacent cutting discs of each cutting disc block. Preferably, a second groove is provided at an axial distance from the first groove in each case. The grooves may be used to guide each cutting disc block on a carrier when the corresponding cutting disc block is removed from the grinder housing. Such a carrier may be attached to the grinder housing for the purpose of removing the first and / or second cutting disc blocks at this time.

[0029] In a second aspect of the present invention or in a preferred additional embodiment of a two-shaft grinder according to the first aspect of the present invention, the two-shaft grinder further comprises a first drive motor preferably configured to drive a first cutting disc block through a first transmission, a second drive motor preferably configured to drive a second cutting disc block through a second transmission, and an electronic control unit for controlling the two drive motors. By providing two motors, the first and second cutting disc blocks can be driven independently, so that the two-shaft grinder can operate in different modes. The drive motors may be of any type, such as an electronic motor, a hydraulic motor, etc. Preferably, a first coupling is provided between the first cutting block and the first drive motor or the first transmission, and a second coupling is provided between the second cutting block and the second drive motor or the second transmission. The first coupling preferably has a first centering means for centering the first drive motor or the first transmission with respect to the first cutting disc block, and the second coupling preferably has a second centering means for centering the second drive motor or the second transmission with respect to the second cutting disc block. The first and second centering devices are preferably self-centering. When the first and second cutting disc units are removed from the 2-shaft grinder, the first and second couplings are preferably separated to separate the cutting disc block from the first and second drive motors and gears, respectively. The first and second clutches are preferably solid clutches. The first and second centering devices are also preferably provided to align the first and second cutting disc blocks with the first and second drive motors and transmissions, respectively. In this way, in addition to radial misalignment, angular errors can also be compensated, and each element can be aligned with each other.

[0030] The first and second centering devices preferably each have a corresponding cone section, and these cone sections engage with each other by a clamping method. They preferably engage with each other so that self-centering is achieved. For example, a female cone is provided on a gear or motor output shaft, and a male cone is provided on a corresponding stub shaft or shaft journal of a cutting block. The cone angle is preferably selected so that self-locking or friction locking does not occur.

[0031] Furthermore, it is preferable that the first and / or second drive motors be mounted in a floating manner. Preferably, they are mounted on the grinder housing or on the machine frame. Preferably, when the first and second couplings are engaged, the drive motors are carried by the first and second cutting disk units and are supported laterally on their respective rotational axes. Preferably, the first and second drive motors, together with the first and second gears, are supported by the first and second torque supports, where appropriate. However, the first and second torque supports do not serve to center the first and second drive motors and / or gear units. Only when the first and second couplings are separated do the first and second torque supports also support the respective weights of the first and second drive motors, preferably together with the first and second gear units, where appropriate. This greatly simplifies the assembly or disassembly of the cutting disk units. As was required in the prior art, there is no need to assemble or disassemble the drive motors separately or to center them relative to the cutting disk units. Instead, only the coupling part must be opened or closed, and all operations are to release the disc motor from the cutting disc block or to coupling the disc motor to the cutting disc block and simultaneously center it.

[0032] In another preferred embodiment, an electronic control unit is connected to a first drive motor, and the electronic control unit is arranged to control the drive motor in at least a first operation mode and a second operation mode—different from the first operation mode. The first and second operation modes are preferably different in the rotational direction, speed, torque, speed change and / or drive profile of the first and second cutting blocks.

[0033] Preferably, the electronic control unit is connected to a first drive motor to supply power to the first drive motor, preferably to determine a first current consumption of the first drive motor, and is connected to a second drive motor to supply power to the second drive motor, preferably to determine a second current inflow of the second drive motor.

[0034] Preferably, the electronic control unit is also configured to control the drive motor in a first operation mode so that the cutting disc block is driven in opposite directions at substantially the same rotational speed, and to control the drive mode in a second operation mode so that the cutting disc block is driven at different rotational speeds and / or in the same rotational direction.

[0035] According to a second aspect, the present invention is based on the particular advantage of providing two drive motors that can be controlled independently of each other. In this way, different speeds, including variable speeds, can be easily set, and different modes of operation can be executed. In the prior art, a two-shaft grinder is generally driven by a single drive motor, whereby the cutting disc blocks are coupled together via a gearbox. A two-shaft grinder using two drive motors is also known in principle, but these motors cannot be controlled independently. Independent control of the drive motors allows not only the selection of a specific mode of operation but also the diagnosis of the two-shaft grinder. Accordingly, the current consumption of each drive motor and the torque applied to each cutting disc block accordingly can be determined. If, for example, it is discovered that one of the cutting disc blocks is bearing a significantly increased load for a specific period of time, this may indicate a failure of the two-shaft grinder. On the other hand, foreign matter may have been trapped in the area of ​​the cutting disc block, which may have caused the increased load. On the other hand, the corresponding cutting disc block may be damaged. Both cases can be determined by the increased load absorption of each drive motor.

[0036] If two cutting disc blocks are driven in opposite directions at essentially the same speed, uniform size reduction is achieved. On the other hand, different speeds eventually cause stronger relative movement between the cutting disc blocks, allowing them to freely "mill" against each other. Here, in a second operating mode, it is particularly advantageous if the first cutting disc block is driven at a first speed and the second cutting disc block is driven at a second speed, such that for a first predetermined time period, the first speed is higher than the second speed, and then for a second predetermined time period, the second speed is higher than the first speed. In this way, the respective spaces between the blades of the cutting disc blocks can freely mill against each other. Furthermore, such alternating speed changes of the cutting disc blocks eventually result in a more uniform load and, consequently, more uniform wear on these blocks. In both cases, this leads to improved maintenance and an improved service life of the 2-shaft grinder.

[0037] The rotational direction of the joint of the cutting disc blocks is particularly useful if foreign matter becomes trapped in the crushing chamber. For example, one of the maintenance hatch covers can be opened and the cutting disc blocks can be driven in the same direction so that the foreign matter can be transported out of the 2-shaft crusher through the opened maintenance hatch cover. If a corresponding maintenance hatch cover is provided, according to the first aspect of the invention and also a lifting device, such as a hydraulic system, for opening the corresponding maintenance hatch cover, this may also be automated and / or periodic. In this case, an electronic control unit also controls the lifting device to cause the maintenance hatch cover to be opened for a short period of time. The control unit may have or be connected to an enable switch through which the opening of the corresponding maintenance hatch cover may be further operated. Such an enable switch may increase operator safety. After the foreign matter is discharged, the maintenance hatch cover may then be moved back to a closed position by the electronic control unit if necessary.

[0038] Preferably, the electronic control unit includes an internal memory and a processor, the internal memory stores a code means internally, and the code means, when executed by the processor, causes the electronic control unit to control the first and second drive motors as described.

[0039] In a preferred embodiment, the electronic control unit is configured to control the drive motor so that the cutting disc blocks have a low differential speed relative to each other. A low differential speed has proven to be particularly suitable for milling the intermediate space between the cutting discs. Here, it is also preferable that one cutting disc block and then another cutting disc block be driven at a higher speed alternately. These predetermined periods are preferably about 30 seconds, 1 minute, 2 minutes, 10 minutes, or 1 hour.

[0040] In a preferred embodiment, the electronic control unit is configured to control the drive motor so that only one of the cutting disc blocks rotates while the other is stopped. This is particularly useful for transporting a jammed element out of the gap from the stopped cutting disc block. Additionally, the stopped cutting disc block may be rotated at a very low speed—approximately 10% or 5% of the speed of the faster rotating cutting disc block. In this way, the stopped or slow-rotating cutting block can be freely milled either continuously or in small increments.

[0041] In this process, the rotary cutting disc block is preferably rotated in the opposite direction to the grinding direction. As a result, the jammed element can be transported in the direction of the inlet opening and finally out of the 2-shaft grinder, for example, through one of the open maintenance hatch covers.

[0042] It has been found that various control strategies can be used to solve the problems of a 2-shaft grinder. For example, as a first problem-solving strategy, the ratio of rotational speeds can be swapped. That is, for example, if the first cutting block rotates at a faster speed than the second cutting block, this is reversed so that the second cutting block rotates at a faster speed than the first cutting block. A second problem-solving strategy is to stop one cutting block or reduce the rotational speed of the second cutting block to 5% to 10%. A third problem-solving strategy is to change the rotational direction of the cutting disc block that rotates when the second problem-solving strategy is used. A fourth problem-solving strategy is to drive the cutting disc block in the same direction, preferably by opening one or both of the maintenance hatch covers. Additionally, in a fifth problem-solving strategy, it may also be conceivable to change the rotational speed for a short period of time, for example, by pulsed, by changing it into a sine wave form, or by driving at maximum power for a short period of time. The electronic control unit may be designed to sequentially undergo the aforementioned problem-solving strategies upon failure—specifically determined based on the current consumption of the first and second drive motors. Each problem-solving strategy is preferably performed for a predetermined duration. If it is determined that the failure still exists or has not been sufficiently corrected, the next problem-solving strategy is applied. Here, the electronic control unit may be made to learn. In particular, learning may be accomplished such that if an additional error occurs after the first error has been corrected, the electronic control unit applies the last successful problem-solving strategy first, and then applies the others only afterward. In this way, efficiency can be increased. Preferably, a hierarchy of problem-solving strategies—determined by their success frequency—is stored in the electronic control unit. It is desirable to apply problem-solving strategies according to this hierarchy.

[0043] In a desirable further development, the gear unit is a bevel gear unit. On the one hand, bevel gear units are efficient, and on the other hand, they allow for a very space-saving arrangement of the drive motor. Preferably, the bevel gear unit is designed as a helical gear unit so that noise reduction and surface pressure within the gear unit can be reduced.

[0044] In a third aspect, the present invention solves the aforementioned problem by a method of servicing a two-shaft grinder, preferably one of the preferred embodiments of the two-shaft grinder described above according to the first aspect and / or the second aspect of the present invention. The method comprises the steps of moving a first maintenance hatch cover from a closed position to a release position; and removing a first cutting disc unit in a horizontal and lateral direction, comprising a first cutting disc block having a plurality of first cutting discs disposed on a first hub body such that there is a space between each of two adjacent first cutting discs, wherein the first cutting disc unit has a first bearing unit having a first bearing housing at a first axial end and a second bearing unit having a second bearing housing at a second axial end, and the first cutting disc block is rotatably supported about a first rotation axis. Lateral removal preferably refers to the flow direction of the two-shaft grinder from an inlet opening to an outlet opening. Laterally, with respect to the inlet opening and the outlet opening, the cutting disc unit is removed horizontally according to this method. It must be understood that the horizontal direction is not strictly in a geometric sense, but that practically, the removal of the horizontal direction is sufficient.

[0045] The two-shaft grinder according to the first aspect of the present invention and the method according to the third aspect of the present invention are particularly similar to those described in the dependent claims and have the same sub-aspects. In this regard, the above description regarding the first aspect of the present invention is fully referenced. By this method, similar or identical advantages are evident as described with reference to the two-shaft grinder according to the first aspect of the present invention. In particular, the first cutting disc assembly can be removed from the two-shaft grinder without disassembling the inlet hopper, etc. According to the present invention, this is done laterally and horizontally, so replacement is significantly simplified. Preferably, the method also includes the step of removing a second cutting disk unit in a horizontal and lateral direction, comprising a second cutting disk block having a plurality of second cutting disks disposed on a second hub body such that there is a space between each of two adjacent second cutting disks, wherein the second cutting disk unit has a third bearing unit having a third bearing housing at a first axial end and a fourth bearing unit having a fourth bearing housing at a second axial end, and the second cutting disk block is rotatably mounted about a second rotation axis. Preferably, the first cutting disk unit or the second cutting disk unit is removed from the 2-shaft grinder in a transverse direction on its respective rotation axis.

[0046] Preferably, the steps are performed without exposing the inlet opening and / or the outlet opening, particularly without disassembling the hopper at the inlet opening and / or the outlet tube at the outlet opening.

[0047] According to an embodiment, a step of releasing the counter holder may be performed prior to the removal step. Preferably, the step of releasing the counter holder is performed after the step of moving the first maintenance hatch cover from the closed position to the release position. The step of releasing the counter holder may include, in particular, a step of releasing the first, second, third, and fourth counter holders by releasing the screw connection between the first, second, third, and / or fourth counter holders and the grinder housing of the 2-shaft grinder.

[0048] Preferably, the method further comprises the steps of inserting a cutting disc unit in a horizontal and lateral direction, preferably attaching a counter holder to secure the first cutting disc unit positively and / or non-positively to the grinder housing, and moving the first maintenance hatch cover from a release position to a closed position.

[0049] Furthermore, in a fourth aspect, the present invention comprises a method for operating a two-shaft grinder, preferably a two-shaft grinder according to one of the previously described embodiments of a two-shaft grinder according to the first and / or second aspects of the present invention. This method for operating the two-shaft grinder may be understood as a further development of a method for servicing the two-shaft grinder, and the steps described below may particularly occur after or before servicing the two-shaft grinder. In a first embodiment, the method for operating the two-shaft grinder comprises the steps of: driving two cutting disc blocks in a first operating mode during a first operating period; terminating the first operating mode at the end of the first operating period; and driving two cutting disc blocks in a second operating mode during a second operating period.

[0050] Preferably, the first operation mode includes the step of driving two cutting disc blocks in opposite directions at substantially the same speed, and the second operation mode includes the step of driving only one of the two cutting disc blocks while the other is stopped. During the first operation period, the opposite-rotational driving of the two cutting disc blocks at substantially the same speed is preferably performed during the normal operation of the two-shaft grinder. In the cleaning operation, then, preferably, only one of the two cutting disc blocks is driven while the other is stopped. In this way, the intermediate space in the stopped cutting disc block can be "freely milled" by the rotating cutting disc block, and the jammed part can be cleaned.

[0051] Additionally or alternatively, the cutting blocks may be driven at substantially the same speed in the first operating mode and at different speeds in the second operating mode. These blocks may also be driven in opposite directions in the first operating mode and in the same direction in the second operating mode.

[0052] Two cutting disc blocks are driven in opposite directions at essentially the same speed, but the speeds are preferably alternate. Essentially the same speed also includes speeds that are slightly different from each other. During normal operation, preferably one of the cutting disc blocks rotates at a higher speed than the other cutting disc block. In this respect, the method comprises the steps of driving a first cutting disc block at a first rotational speed during the first part of the first operation period, preferably during normal operation, and driving a second cutting disc block at a second rotational speed, wherein the first rotational speed is greater than the second rotational speed. During the second part of the first operation period following the first part, the steps of driving the first cutting disc block at a first speed and driving the second cutting disc block at a second speed—wherein the second speed is greater than the first speed—. This may be followed by third, fourth, and fifth sections, in which case the third section is preferably formed like the first section, and the fourth section is formed like the second section. Preferably, the same applies to an additional N+1 sections. The method preferably comprises the step of moving a side maintenance hatch cover from a closed position to a release position; and further includes the step of driving two cutting disc blocks in the same direction toward the maintenance hatch cover to discharge foreign matter. Preferably, the cutting disc blocks rotate in this process at a slower speed than in normal operation, preferably at a speed of approximately 10% or less of the maximum speed. Elements that cannot be crushed by the cutting disc blocks may enter the crushing chamber through the inlet opening. This may be, for example, large metal, stones, etc. Such foreign matter must be discharged. Meanwhile, this can be done manually by an operator reaching into the inlet opening through the inlet hopper—while the cutting disc blocks are stationary—and manually removing the foreign matter.According to the solution proposed herein, however, either the lateral maintenance hatch cover, the first or the second maintenance hatch cover, moves from a closed position to a release position, and the cutting disc block rotates in the direction of this maintenance hatch cover. That is, with respect to the orientation of the 2-shaft grinder, the cutting teeth of the cutting disc block above it move in the direction of the maintenance hatch cover. Accordingly, if the maintenance cover is at the 3 o'clock position with respect to the rotation axis of the cutting disc unit, the cutting disc block must rotate clockwise. If the maintenance hatch cover is at the 9 o'clock position, the cutting disc block rotates counterclockwise. Foreign material typically sits on the cutting disc block and, consequently, cannot be ground. By driving the cutting disc block in the same direction toward the maintenance hatch cover, the foreign material can therefore be transported out of the grinding chamber. These steps may also be performed instead of the step in which only one of the two cutting disc blocks is driven during the second operation period while the other remains stationary. The opening of the first or second maintenance hatch cover may be performed by the control unit. This may include or be connected to an operable switch. This method may include a step of enabling the first maintenance hatch cover to be moved from a closed position to an operable position by the operable switch.

[0053] Preferably, the method further comprises the steps of closing a maintenance cover after discharging foreign matter and driving the first and second cutting disc blocks in normal operation. Preferably, normal operation includes the step of driving the cutting disc blocks in opposite directions at substantially the same speed.

[0054] Additionally, the method includes the step of detecting a first power inflow of a first drive motor of a first cutting block; the step of detecting a second power inflow of a second drive motor of a second cutting block; and the step of determining a failure of a 2-shaft grinder based on the detected first and second power inflows. For example, when an electric motor is used as the drive motor, current consumption can be measured. Alternatively, torque, stress on the shaft, force on the bearing or coupling part, noise, etc., can be detected.

[0055] Embodiments of the present invention will now be described below with reference to the drawings. These drawings are not intended to depict the embodiments to actual scale; rather, where useful for illustrative purposes, the drawings are schematic and / or slightly distorted. For additions to gauges that are immediately recognizable in the drawings, please refer to the relevant prior art. It should be kept in mind that a wide variety of modifications and changes to the shapes and details of the embodiments may be made without departing from the general idea of ​​the present invention. The features of the present invention disclosed in the detailed description, drawings, and claims may be necessary for further development of the present invention, individually and in any combination. Furthermore, any combination of at least two features disclosed in the detailed description, drawings, and / or claims is within the scope of the present invention. The general idea of ​​the present invention is not limited to the specific form or detail of the preferred embodiment that is limited to any feature that is limited by comparison with the features described below or claimed in the claims. In the case of specified design ranges, values ​​within the specified limits are also intended to be disclosed as limit values ​​and may be used and claimed as desired. For simplification, the same reference numerals are used below for identical or similar parts or parts having the same or similar functions.

[0056] Further advantages, features, and details of the present invention will become apparent from the following description of preferred embodiments and drawings. Brief explanation of the drawing

[0057] FIG. 1 is a perspective view of a 2-shaft crusher with closed first and second maintenance hatch covers. FIG. 2 is a perspective view of the 2-shaft crusher of FIG. 1 with open first and second maintenance hatch covers. Fig. 3a is a detailed view of Fig. 1. Fig. 3b is a detailed view of Fig. 2. FIG. 4 is a schematic diagram illustrating the lateral removal of the first and second cutting disk units. FIG. 5 is a schematic diagram of a parallel motion system for moving a first maintenance hatch cover from a closed position to a release position. FIG. 6 is a perspective view of the 2-shaft crusher from FIG. 1 with the maintenance hatch cover open and the cutting disc unit removed. FIG. 7 is a perspective view of a cutting disk unit including first and second counter holders. Figure 8 shows a cross-section of a cutting disk unit. Fig. 9 is another detailed view of Fig. 1. Figure 10 is an exploded perspective view of the joint. FIG. 11 is a cross-sectional view through the assembled joint of FIG. 10. Figure 12 illustrates the torque support portion of the drive motor. Figure 13 is a schematic diagram of the drive control of a 2-shaft grinder. Figure 14 is another schematic diagram of the drive control of a 2-shaft grinder. Specific details for implementing the invention

[0058] A two-shaft grinder (1) for grinding solids or solids in liquids has a grinder housing (2) - having an internal grinding chamber (4). The grinder housing (2) is placed on a machine frame (6), which supports the grinder housing (2). Referring to FIG. 1, on the upper side of the grinder housing (2), a feed hopper (10) is provided, and an inlet opening (8) is formed. The feed hopper (10) now has a grate (11) to prevent excessively large objects from passing through the feed hopper (10) into the inlet opening (8). The grate (11) is optional and may also be omitted, for example, if larger objects fill the feed hopper (10). Referring to FIG. 1, an outlet opening (12) of the two-shaft grinder (1) is placed on the lower side and is not shown in detail here. The discharge opening (12) is positioned opposite the inlet opening (8) so that fluid can flow vertically from the top to the bottom through the 2-shaft crusher (1) with reference to FIG. 1. When installed, the discharge opening (12) may be connected to a pipe or the like to discharge crushed material.

[0059] Inside the grinding chamber (4), the first and second cutting disk units (14, 16) rotate during operation, which will be described in more detail below with reference to FIGS. 4, FIGS. 6, FIGS. 7 and FIGS. 8. The first cutting disk unit (14) has a first rotation axis (A1), and the second cutting disk unit (16) has a second rotation axis (A2). The rotation axes (A1, A2) are parallel to each other but offset. In this way, the individual blades of the cutting disk units (14, 16) can interlock with each other to cut the material. This is known in principle.

[0060] A first drive motor (18) is provided to drive the first cutting disk unit (14), and a second drive motor (20) is provided to drive the second cutting disk unit (16). Both motors are controlled by a common electronic control unit (22), which is also attached to the machine frame (6). The electronic control unit (22) will also be described in more detail below. The first drive motor (18) is equipped with a first gear (19) and is connected to the first cutting disk unit (14) through this gear. The second drive motor (20) is equipped with a second gear (21) and is connected to the second cutting disk unit (16) through this gear. In this way, the accommodation of the first and second drive motors (18, 20) is simplified. The first and second gears (19, 21) are preferably bevel gears, but are not shown in more detail here.

[0061] As is more evident from FIG. 1, the grinder housing (2) has an inlet side (24), on which the hopper (10) is received and an inlet opening (8) is formed. The inlet side (24) is oriented substantially upward in the embodiment shown in FIG. 1. Furthermore, the grinder housing (2) has an outlet side (26), which is the lower side of the grinder housing (2), and this outlet side (26) includes an outlet opening (12). First and second drive motors (18, 20) are provided on the first and second end faces (28, 30), respectively. The first and second end faces (28, 30) are positioned substantially perpendicular to the first and second rotation axes (A1, A2) and interconnect the inlet side (24) and the outlet side (26). Furthermore, first and second transverse sides (32, 34) are formed on the crusher housing (2).

[0062] One problem with conventional 2-shaft grinders is the maintenance of the first and second cutting disc units (14, 16). For example, the first cutting disc unit (14) has a first cutting disc block (40), and the second cutting disc unit (16) has a second cutting disc block (42) (see FIG. 4 and FIG. 7). Each of the cutting disc blocks (40, 42) is provided with a plurality of cutting discs. That is, the first cutting disc block (40) is provided with a first cutting disc (44) (in FIG. 7 and FIG. 8, only one reference number is provided in each figure), and the second cutting disc block (42) is provided with a second cutting disc (46). The first and second cutting discs (44, 46) are each axially spaced apart from each other so that the cutting discs (44, 46) of the first and second cutting disc blocks (40, 42) can interlock with each other, as is basically known in the prior art, particularly with reference to DE 20 2010 010662 U1 and WO 2018 087 398. The cutting discs (44, 46) of the first and second cutting disc blocks (40, 42) wear out over time and must be maintained, i.e., replaced. To simplify this, the present invention implements a horizontal maintenance concept, which will be described later.

[0063] To enable horizontal maintenance, the 2-shaft grinder (1), more specifically the grinder housing (2), has a first maintenance hatch cover (50), which is preferably formed on the first transverse side (32) of the grinder housing (2). Through the first maintenance hatch cover (50), the first cutting disc unit (14) can be removed from the grinder housing (2). The second cutting disc unit (16) can also be removed from the grinder housing (2) through the first maintenance hatch cover (50). However, according to the embodiment illustrated herein, the grinder housing (2) has a second maintenance hatch cover (52) assigned to the second cutting disc unit (16). In the following, the first and second maintenance hatch covers (50, 52) will always be described, and it should be understood that there may be embodiments including only one of the maintenance hatch covers (50, 52) that provide access to the two cutting disc units (14, 16).

[0064] In FIG. 1, the first maintenance hatch cover (50) is in a closed position (P11). The second maintenance hatch cover (52) is also in a closed position (P12). In FIG. 2, however, the first maintenance hatch cover (50) is in a release position (P21), and the second maintenance hatch cover (52) is also in a release position (P22). In the release positions (P21, P22), the first and second maintenance hatch covers (50, 52) are pivoted upward, preferably without performing rotation around their own axes. To enable such pivoting of the first and second maintenance hatch covers (50, 52), the 2-shaft crusher (1) has a first parallel motion system (54) for the first maintenance hatch cover (50) and a second parallel motion system (56) for the second maintenance hatch cover (52). The first and second parallel motion systems (54, 56) are configured substantially identically, so only the first parallel motion system (54) will be described below. The second parallel motion system (56) may be configured in a manner similar to the first parallel motion system (54). The first and second parallel motion systems (54, 56) are particularly visible in FIGS. 3a and 3b, which will be referenced below. Additionally, the parallel motion systems (54, 56) are again illustrated in FIGS. 4 and 5. The first parallel motion system (54) has a first parallelogram lever (58) and a second parallelogram lever (60). The first parallelogram lever (58) is connected to the crusher housing (2) at a first joint point (59a) and to the first maintenance hatch cover (50) at a second joint point (59b). The second parallelogram lever (60) is connected to the crusher housing (2) at the first joint point (61a) and to the first maintenance hatch cover (50) at the second joint point (61b). The first joint points (59a, 61a) of the first and second parallelogram levers (58, 60) are substantially vertically aligned up and down and substantially aligned over the maintenance hatch cover (50).At the closed position (P11, P12), the first and second parallelogram levers (58, 60) pivot downward so that the first maintenance hatch cover (50) is substantially aligned below the first and second joint points (59a, 61a). The parallel motion system (54) is connected to the first lifting device (62), which includes the first pneumatic cylinder (63). In the illustrated embodiment, the pneumatic cylinder (63) engages with the first parallelogram lever (58) to pivot it around the first pivot point (59a). Eventually, the first maintenance hatch cover (50) is raised from the closed position (P11) and moves upward to reach the release position (P21) illustrated in FIGS. 2, FIGS. 3b, and FIGS. 4.

[0065] The first and second parallel motion systems (54, 56) are described only with reference to the first end surface (34) of the crusher housing (2). A corresponding parallel motion system is also positioned on the second end surface (30), so that the first and second maintenance hatch covers (50, 52) can be raised and lowered via two such parallel motion systems.

[0066] In particular, as can be seen in FIG. 4, the first and second scrapers (66, 68) are positioned on the first and second maintenance hatch covers (50, 52) to prevent non-crushing material from passing between the maintenance hatch covers (50, 52) and the corresponding cutting disc blocks (14, 16) during operation, while on the other hand, they serve to keep the intermediate space between the first and second cutting discs (40, 44) free. The first and second scrapers (66, 68) are positioned here on the first and second maintenance hatch covers (50, 52) and move together with the first and second maintenance hatch covers (50, 52) from a closed position to a release position. In this way, the first and second cutting disc units (14, 16) are released particularly easily and extensively.

[0067] After the first and second maintenance hatch covers (50, 52) are moved to release positions (P21, P22), the first and second cutting disc units (14, 16) can be removed from the grinder housing (2) along the first and second removal directions (E1, E2) (compare with FIG. 2). In FIG. 2 and FIG. 3b, the first and second cutting disc units (14, 16) have already been removed. Schematically, the removal of the first and second cutting disc units (14, 16) can be seen in FIG. 4, and will now be described in more detail with reference to FIG. 4, FIG. 6, FIG. 7, FIG. 8 and FIG. 9.

[0068] The first cutting disk unit (14) is shown separately and in a perspective view in FIG. 7. A cross-section of the first cutting disk unit (14) is shown in FIG. 8. The cross-section in FIG. 8 is in the horizontal direction, and FIG. 8 is a plan view. Although only the first cutting disk unit (14) is shown in FIG. 7 and FIG. 8, the second cutting disk unit (16) has the same structure, and it should be understood that the following description also applies to the second cutting disk unit (16).

[0069] The first cutting disc (44) is disposed on the first hub body (70) and, in the illustrated embodiment, is formed integrally with it. Thus, the cutting disc block (40) is formed as a so-called monolithic cutting disc block. However, this is not mandatory and includes embodiments in which the first cutting disc (40) is connected to the first hub body (70) in a non-positive and / or positive manner. Also illustrated in FIG. 8 are optional first grooves (300) and optional second grooves (300) formed on the hub body (70). The grooves (300) are indicated by dashed lines to indicate that they are optional.

[0070] Referring to FIG. 8, on the left, the first hub body (70) extends to a first stub shaft (72) that can be connected to the first transmission (19). Referring to FIG. 8, on the right, the cutting disc block (40) includes a second stub shaft (76). The left end of the cutting disc block (40)—where the first stub shaft (72) is positioned—is received in a first bearing unit (80), and the second stub shaft (76) is received in a second bearing unit (82). Accordingly, a second cutting disc unit (16) is also formed and has a third bearing unit (84) and a fourth bearing unit (86) (compare FIG. 4).

[0071] The first bearing unit (80) has a first bearing housing (81), the second bearing unit (82) has a second bearing housing (83), the third bearing unit (84) has a third bearing housing (85), and the fourth bearing unit (86) has a fourth bearing housing (87). Each of the first and second cutting disc blocks (40, 42) is rotatably supported within the first, second, third, and fourth bearing housings (81, 83, 85, 87). By the first, second, third, and fourth bearing housings (81, 83, 85, and 87), each of the first and second cutting disc units (14, 16) is attached to the grinder housing (2). Referring to FIG. 8, it can be seen that the first bearing (90), which is in the form of a double angle contact roller bearing in an X arrangement, is provided in the first bearing housing (81). A first seal (92) is provided between the bearing housing (81) and the first bushing (91) that supports the outer ring of the first bearing (90). The first seal (92) is configured here as a contact seal and serves to seal the cutting pulley block (44) from the bearing housing (81). The inner ring of the first bearing (90) is pressed onto the first stub shaft (72) and is frictionally fixed on the first stub shaft (72). In addition, a nut (93) is provided to support the inner ring. The bearing housing (81) is then closed by a first bearing cover (94). The first bearing cover (94) is screwed against the first bearing housing (81) by a screw (Fig. 9). A first lubrication port (95) is also provided in the first bearing cover (94) to supply lubricating oil to the first bearing (90).

[0072] The second bearing unit (82) has a second bearing (96) formed as a roller bearing and a floating bearing. The outer bearing ring is again received in the second bearing housing (83), and the inner ring is pressed onto the second stub shaft (76). The second shaft journal (76) is detachably connected to the hub body (70) as previously described. A second contact seal (98) is positioned between the bearing housing (83) and a second bushing (97) that frictionally engages on the second shaft journal (76), and now seals the cutting block (40) from the bearing housing (82) to prevent fluid from reaching the second bearing (96). A second bearing cover (99) closes the second bearing housing (82), and the second bearing cover (99) is now secured to the second bearing housing (82) by screws. The second bearing unit (82) is formed similarly to the third bearing unit (85), so that the shape of the second bearing cover (99) corresponds to the shape of the third bearing cover (100) shown in FIG. 9. A third lubrication port (102) is provided in the third bearing cover (100) to supply lubricating oil to the bearing housed therein. A similar lubrication port is also provided for the second bearing (96) and the fourth bearing (not shown).

[0073] A particular advantage of the present invention is that the cutting disc unit (14, 16) can be removed from the grinder housing (2) together with the first, second, third, and fourth bearing units (80, 82, 84, 86). In other words, disassembly of the bearings themselves is not required within the grinder housing, but this advantage makes these bearings much less susceptible to damage and also facilitates maintenance. To this end, the first and second bearing housings (81, 83) include first and second mounting surfaces (104, 106), the mounting surfaces (104, 106) on one side in contact with the first and second mounting recesses (108, 110) of the grinder housing (2) (compare FIG. 4), and on the other side can cooperate with the first and second counter holders (110, 112) to secure the first cutting disc unit (14) to the grinder housing (2). The first and second counter holders (110, 112) are also shown in cross-section in FIG. 8, as the cross-section according to FIG. 8 is a top view. To achieve additional sealing here, the first and second O-rings (105, 107) are also placed on the first and second mounting surfaces (104, 106), and the O-rings can make contact against the first and second counter holders (110, 112) on one side and against the first and second mounting recesses (108, 110) on the other side, so as to seal the first and second bearing housings (81, 83) against the grinder housing (2).

[0074] The third and fourth bearing housings (84, 86) are similarly configured and can be inserted into the third and fourth mounting recesses (114, 116) (compare with FIG. 4) and secured thereto by the corresponding third and fourth mating retainers (118, 120). The first, second, third, and fourth mating retainers (110, 112, 118, 120) have mating retainer surfaces (122, 124) corresponding to the first and second mounting surfaces (104, 106) of the first and second bearing housings (81, 83). Similarly, the third and fourth mating retainers (118, 120) have such surfaces. Additionally, the first and second mating retainers (110, 112) each have a mating hole (126) that allows the first and second mating retainers (110, 112) to be joined against the grinder housing (2) by being engaged by a mating retainer screw (128). The same mounting hole (126) and counter holder screw (128) are also provided in the third and fourth counter holders (118, 120) (compare with FIG. 9). The counter holder screw (128) and accordingly also the first and second counter holders (110, 112) are concealed by the first maintenance hatch cover (150) when the first maintenance hatch cover (150) is in the closed position (P11). Similarly, the mating retainer screws (128) of the third and fourth mating retainers (118, 120) are concealed by the second maintenance hatch cover (52) when the second maintenance hatch cover (52) is in the closed position (P12). This prevents the counter holder from becoming loose even when the first and second maintenance hatch covers (50, 52) are in the closed position.

[0075] Ultimately, in order to remove the first and second cutting disc units (14, 16) from the grinder housing (2), the first and second maintenance hatch covers (50, 52) must first be moved to the release position (P21, P22). Subsequently, the first and second counter holders (110, 112) and the third and fourth counter holders (118, 120), respectively, must be released. Prior to this, a maintenance bracket (130) is preferably attached to the machine frame (6) as shown in FIG. 6 to prevent the corresponding cutting disc unit (the second cutting disc unit (16) in FIG. 6) from falling after the third and fourth counter holders (118, 120) are released. The maintenance bracket (130) is supported on the machine frame (6) and, in this embodiment, has first, second, and third supports (131, 132, 133), wherein an optional gripper (134) is provided on the second support (132). In other embodiments, only two carriers may be provided, or four or more carriers may be provided. The gripper (134) has a claw (135) capable of grasping the cutting disc assembly (16) circumferentially. A pull rod (136) having handles (137a, 137b) is provided on the claw (135) so that the claw (135) can be guided to the cutting disc unit (16). As long as the cutting disc unit (16) is still placed within the grinder housing (2), it must be grasped by the claw (135). The cutting disc unit can be pulled out of the grinder housing (2) through a pulling rod (136) that is secured to the first, second, and third struts (131, 132, 133). The cutting disc block (40) may be provided with a first groove (300) as shown in FIG. 8. The width of the groove (300) is preferably slightly wider than the width of the struts (131, 132, 133).The struts (131, 132, 133) are positioned below the cutting disc assembly (16) so that the groove (300) and the struts (131, 132, 133) can be mutually locked. The groove (300) allows the cutting disc unit (16) to be positioned axially over the support (131, 132, 133). The cutting disc unit (16) can be rolled, for example, manually, along the support (131, 132, 133), whereby the cutting disc unit (16) is anchored to the first, second, and / or third support (131, 132, 133) and guided over the groove (300), so that the axial positioning of the cutting disc unit (16) is maintained even while rolling outward. This configuration has the advantage that the position of the bearing housing (81, 83) is maintained axially with respect to the axis of rotation or is fixed by the groove (300). From here, the cutting disc unit (16) can then be transported with the help of a crane. Preferably, the first and second cutting disc units (14, 16) are re-inserted into the crusher housing (2) in a similar manner. This allows for simple and safe maintenance on one hand, and minimizes the risk of injury on the other.

[0076] The first and second cutting disk blocks (40, 42) of the first and second cutting disk units (14, 16) are connected to the first and second driving motors (18, 20) through the first and second connecting parts (200, 202) as illustrated in FIGS. 10 and 11. Of these connecting parts (200, 202), only one, namely the first connecting part (200), will be described below as an example. The same design is preferably applied to the second connecting part (202), but it may be a different or similar design.

[0077] In the illustrated embodiment, the first and second cutting disc blocks (40, 42) are connected to the first and second drive motors (18, 20) through the first and second gearboxes (19, 21), but the gearboxes are not mandatory, and the drive motors (18, 20) can also be directly coupled to the cutting disc blocks (40, 42).

[0078] The first gearbox (19) has a first output shaft (204), and the first output shaft (204) is provided with a first clutch disc (206) at its upper end. The first clutch disc (206) has a first conical portion (208)—formed here as a conical shape—(see FIG. 11). A second clutch disc (210) is rotatably seated on a shaft journal (72). The first clutch disc (206) and the second clutch disc (210) are provided with a plurality of through holes so that they can be clamped against each other by a clutch nasse (212). A centering cup (214) is provided to center the first clutch disc (206) against the second clutch disc (210) and center the output shaft (204) against the shaft journal (72). The centering cup (214) also has a through hole and can preferably be clamped against the first and second clutch discs (206, 210) by a clutch screw (212). The centering cup (214) has a collar (216) positioned on the radial centering surface (218) of the second clutch disc (210) and a base (220) engaged behind the first clutch disc (206). A second cone (222) is formed on the centering cup (214) between the collar (216) and the base (220), corresponding to and working in cooperation with the first cone (208) to be centered. Accordingly, when the coupling screw (212) is tightened, the second cone (222) is pressed against the first cone (208), and the first coupling disc (206) is centered on the centering cup (214).

[0079] To also center the second clutch disc (210) on the shaft journal (72), a first conical ring (224) is provided in this embodiment, extending to a first conical projection (226) between the first clutch disc (210) and the shaft journal (72), and a second conical ring (228) extending to a second conical projection (230) between the first clutch disc (210) and the shaft journal (72) and positioned opposite the first conical ring (224). The two conical rings (224, 228) are tightened together by an eyebolt (232). In this way, the second clutch disc (210) is centered on the shaft journal (72). Furthermore, the output shaft (204) is also aligned with respect to the shaft journal (72) in this manner. Accordingly, angular error and radial misalignment are compensated.

[0080] FIGS. 10 and FIGS. 12 now illustrate in detail the drive bearings of the drive motors. The first drive motor (18) is supported on the machine frame (6) through the first drive bearing (240) (compare with FIG. 1), and the second drive motor (20) is supported on the machine frame (6) through the second drive bearing (242). Only the first drive bearing (240) will be described below, but the same description preferably applies to the second drive bearing (242) as well.

[0081] The first drive bearing (240) includes a first torque support (244) and a second torque support (246). The first drive bearing (240) is designed as a floating bearing and does not center the first drive motor (18) and the first gearbox (19) with respect to the first cutting block (40), and this advantage is achieved through the first coupling (200) as previously described. During operation, the first and second torque support (244, 246) preferably serve only to support torque. These support may also be configured to partially support heavy forces to partially relieve the load on the bearing of the cutting disc block. When the first and second coupling parts (200, 202) are opened, the first and second torque support parts (244, 246) sufficiently absorb the weight force of the first and second drive motors (18, 20) and, if applicable, the first and second gears (19, 21). Therefore, they will move slightly downward.

[0082] Here, the first torque support member (244) includes a first damper device (250) to support torque in a first rotational direction and a second damper device (252) to support torque in a second opposite rotational direction. The second torque support member (246) includes first and second damper devices that are similar to each other (not shown, see FIG. 10). Each damper device (250, 252) includes two rubbers that are also attached to the cross member (254). The cross member (254) is now attached to the first gear housing (260) via the first and second support plates (256, 258) and now also supports the first drive motor (18).

[0083] The first and second drive motors (18, 20) can be controlled independently by an electronic control unit (22). As a result, the 2-shaft grinder (1) can operate in two or more operating modes. For example, in the first operating mode, the first and second cutting disc blocks (40, 42) are controlled to rotate in the same direction at substantially the same speed. Then, in the second operating mode, the drive motors (18, 20) are controlled by the control unit (22) to drive the first and second cutting disc blocks (40, 42) at different speeds and / or in the same direction of rotation. FIG. 13 illustrates such a scenario. The horizontal axis is the time axis, and the speed (n) is identified on the vertical axis. At time (t0), the first cutting block (40) is driven at a higher speed (n1) than the speed (n2) at which the second cutting block (42) is driven. At time (t1), the electronic control unit (22) then begins to reverse and accelerates the second cutting disc block (42) until it reaches a first speed (n1) at time (t2). At the same time, the first cutting disc block (40) is slowed down at time (t1) until it has a lower speed (n2) at time (t2). After a predetermined time period between the second time (t2) and the third time (t3), the 2-shaft grinder (1) continues to operate. At time (t3), the first cutting disc block (40) is accelerated again from speed (n2) to speed (n1)—reaching time (t4). At the same time, the second cutting disc block (42) is decelerated again to reach a second speed (n2) at time (t4). An additional similar period may follow. This mode of operation has the advantage that there is relative movement between the first cutting disc block (40) and the second cutting disc block (42), so that they “freely scratch” each other, that is, any element attached to the gap between the individual cutting discs is transported outward.

[0084] FIG. 14 illustrates an additional mode of operation in which foreign objects (200) are transported outside the crushing chamber (4). When foreign objects (200) that cannot be crushed even in the grate (11) enter the crushing chamber (4), these foreign objects cannot reach the discharge opening (12) because they cannot be crushed and are held on the other side by the rake (66, 68). To automatically transport these foreign objects out of the size reduction chamber, it is preferable to open one of the maintenance hatch covers (50, 52), the second maintenance hatch cover (52) in FIG. 11. Subsequently, the cutting disc block (40, 42) rotates in the direction of the opened maintenance hatch cover, in this case, clockwise. In this way, the foreign objects (200) move toward the maintenance hatch cover (52) opened by the cutting disc block (40, 42) and accordingly fall out of the crusher housing (2).

[0085] In such a mode of operation, it is important to take appropriate safety measures for the operating personnel to prevent subsequent damage to the cutting block exposed laterally. For example, it may be stipulated that such operation can only be performed in a closed room.

[0086] Other such modes of operation may be conceived and preferred, as described above. It is desirable to store such modes of operation in the electronic control unit (22), preferably in the memory provided therein. For this purpose, the electronic control unit (22) preferably has an operation panel (202) (compare with FIG. 1), through which the operator can operate the 2-shaft grinder (1).

Claims

Claim 1 A two-shaft grinder (1) for grinding solid or solid in liquid, comprising: a grinder housing (2) defining an internal grinding chamber (4); an inlet opening (8) in the grinder housing (2) for supplying solid to the grinding chamber (4); an outlet opening (12) in the grinder housing (2) opposite the inlet opening (8) for discharging the ground solid from the grinding chamber (4); a first cutting disc unit (14) comprising a first cutting disc block (40) having a plurality of first cutting discs (44) disposed on a first hub body (70) such that there is a space between each of two adjacent first cutting discs (44); and a second cutting disc unit (16) comprising a second cutting disc block (42) having a plurality of second cutting discs (46) disposed on a second hub body such that there is a space between each of two adjacent second cutting discs (46), wherein the first and second cutting disc blocks (40, 42) are At least a portion of the first cutting disk (44) engages with the space between two adjacent second cutting disks (46), and a portion of the second cutting disk (46) engages with the space between two adjacent first cutting disks (44), and the rotation axes (A1, A2) of these cutting disk blocks are offset axially from each other, wherein the first cutting disk unit (14) has a first bearing unit (80) having a first bearing housing (81) at a first axial end and a second bearing unit (82) having a second bearing housing (83) at a second axial end, and the first cutting disk block (40) is mounted rotatably about a first rotation axis (A1), and the second cutting disk unit (16) has a third bearing unit (84) having a third bearing housing (85) at a first axial end and a fourth bearing unit having a fourth bearing housing (87) at a second axial end. It has a unit (86),A 2-shaft grinder characterized in that the second cutting disc block (42) is rotatably mounted about a second rotation axis (A2), and the grinder housing (2) has a first maintenance hatch cover (50), and the first maintenance hatch cover (50) may have a release position (P21) and a closed position (P11), and at the release position (P21), the first cutting disc unit (14) together with the first and second bearing units (80, 82) are allowed to be removed. Claim 2 A 2-shaft grinder according to claim 1, wherein the grinder housing (2) comprises a second maintenance hatch cover (52), the second maintenance hatch cover (52) may have a release position (P22) and a closed position (P12), and at the release position (P22), allows for the removal of only the second cutting disk unit (16) together with the third and fourth bearing units (84, 86). Claim 3 A 2-shaft grinder according to claim 1 or claim 2, wherein the bearing unit (80, 82, 84, 86) comprises a seal to seal the bearing (90, 96) of the bearing unit (80, 82, 84, 86) against the cutting disc block (40, 42). Claim 4 A two-shaft grinder according to claim 1 or claim 2, wherein each bearing housing (81, 83, 85, 87) of the bearing units (80, 82, 84, 86) can be fixed against rotation in the grinder housing (2) in an assembled state. Claim 5 A 2-shaft grinder according to claim 1 or claim 2, wherein the grinder housing (2) comprises an inlet side (24) having the inlet opening (8), an outlet side (26) having the outlet opening (12), first and second end sides (28, 39) arranged perpendicularly to the first and second rotation axes (A1, A2), and first and second side direction sides (32, 34), and the first maintenance hatch cover (50) is arranged on the first side direction side (32). Claim 6 A two-shaft grinder according to claim 1 or claim 2, wherein the first cutting disk unit (14) can be removed from the grinder housing (2) in a first removal direction (E1) that is transverse to the first rotation axis (A1) and parallel to the plane defined by the first and second rotation axes (A1, A2). Claim 7 A two-shaft grinder according to claim 1 or claim 2, wherein the first cutting disk unit (14) is positively fixed to the grinder housing (2) by first and second counter holders (110, 112). Claim 8 A 2-shaft grinder according to claim 7, wherein the first and second counter holders (110, 112) are concealed by the first maintenance hatch cover (50) when the first maintenance hatch cover (50) is in the closed position (P11) and are accessible when the first maintenance hatch cover (50) is in the release position (P21). Claim 9 A two-shaft grinder according to claim 1 or claim 2, comprising a first parallel motion system (54) for moving the first maintenance hatch cover (50) from the closed position (P11) to the release position (P21). Claim 10 A two-shaft grinder according to claim 9, comprising a first lifting means (62) for moving the first maintenance hatch cover (50) from the closed position (P11) to the release position (P21), which engages with the first parallel motion system (54). Claim 11 A 2-shaft grinder according to claim 1 or claim 2, wherein the first and second cutting disc blocks (40, 42) are provided with at least one first groove (300), and a carrier (131, 132, 133) can be engaged for guidance in the at least one first groove (300). Claim 12 A two-shaft grinder as described in claim 1 or claim 2, comprising: a first drive motor (18) capable of driving the first cutting disc block (40) through a first gear (19); a second drive motor (20) capable of driving the second cutting disc block (42) through a second gear (21); and an electronic control unit (22) for controlling the two drive motors (18, 20). Claim 13 A two-shaft grinder according to claim 12, further comprising: a first coupling portion (200) between the first cutting disk block (40) and the first driving motor (18); and a second coupling portion (202) between the second cutting disk block (42) and the second driving motor (20), wherein the first coupling portion (200) has a first centering means for centering the first driving motor (18) with respect to the first cutting disk block (40), and the second coupling portion (202) has a second centering means for centering the second driving motor (20) with respect to the second cutting disk block (42). Claim 14 A two-shaft grinder according to claim 13, wherein the first and second centering means each comprise corresponding conical portions that are clamped and engaged with each other. Claim 15 In claim 12, the first and second drive motors (18, 20) are in a floating configuration, a 2-shaft grinder. Claim 16 A two-shaft grinder according to claim 12, wherein the electronic control unit (22) is configured to control the drive motor (18, 20) in at least a first operating mode and in a second operating mode different from the first operating mode. Claim 17 A 2-shaft grinder according to claim 16, wherein the electronic control unit (22) is configured to control the first and second drive motors (18, 20) in the first operation mode so that the first and second cutting disk blocks (40, 42) are driven in opposite directions at the same speed (n1, n2), and the electronic control unit (22) is configured to control the first and second drive motors (18, 20) in the second operation mode so that the first and second cutting disk blocks (40, 42) are driven at different speeds (n1, n2) and / or in the same rotational direction. Claim 18 A two-shaft grinder according to claim 12, wherein the electronic control unit (22) is arranged to control the drive motor (18, 20) so that the cutting disk blocks (40, 42) have a low differential speed relative to each other. Claim 19 A two-shaft grinder according to claim 12, wherein the electronic control unit (22) is arranged to control the drive motor (18, 20) so that the cutting disk blocks (40, 42) have alternating speeds. Claim 20 A two-shaft grinder according to claim 12, wherein the electronic control unit (22) is configured to control the drive motor (18, 20) so that only one of the cutting disk blocks (40, 42) rotates while the other one stops. Claim 21 In claim 20, the rotating cutting disc block (40, 42) rotates against the grinding direction, a 2-shaft grinder. Claim 22 A two-shaft grinder according to claim 12, wherein the first and second gears (19, 21) are bevel gears. Claim 23 A method for servicing a 2-shaft grinder (1) as described in claim 1 or claim 2, comprising: moving a first maintenance hatch cover (50) from a closed position (P11) to a release position (P21); and removing a first cutting disc unit (14) having a first cutting disc block (40) having a plurality of first cutting discs (44) disposed on a first hub body (70) such that there is space between each of two adjacent first cutting discs (44), wherein the first cutting disc unit (14) has a first bearing unit (80) having a first bearing housing (81) at a first axial end and a second bearing unit (82) having a second bearing housing (83) at a second axial end, and the first cutting disc block (40) is rotatably mounted about a first rotation axis (A1). Claim 24 A method according to claim 23, wherein the steps are performed without exposing the inlet opening (8) and / or outlet opening (12). Claim 25 A method according to claim 23, comprising the step of releasing the counter holder (110, 112, 118, 120) before the step of removing. Claim 26 A method for operating a 2-shaft grinder (1) as described in claim 12, comprising: - driving two cutting disc blocks (40, 42) in a first operating mode during a first operating period; - stopping the first operating mode at the end of the first operating period; and - driving the two cutting disc blocks (40, 42) in a second operating mode during a second operating period. Claim 27 A method according to claim 26, wherein in the first operation mode, the two cutting disk blocks (40, 42) are driven at the same speed, and in the second operation mode, the two cutting disk blocks are driven at different speeds. Claim 28 A method according to claim 26, wherein in the first operation mode, the two cutting disk blocks (40, 42) are driven in opposite directions, and in the second operation mode, only one of the two cutting disk blocks (40, 42) is driven. Claim 29 A method according to claim 26, comprising: - moving a side maintenance hatch cover (50, 52) from a closed position (P11, P12) to a release position (P21, P22); and - driving the two cutting disc blocks (40, 42) in the same direction and in the direction of the maintenance hatch cover (50, 52) to discharge a foreign object (200). Claim 30 A method according to claim 23, comprising the step of freely moving the first maintenance hatch cover (50) from the closed position (P11) to the release position (P21) by means of a confirmation switch. Claim 31 A method according to claim 26, comprising: - detecting a first power inflow of a first drive motor (18) of the first cutting disc block (40); - detecting a second power inflow of a second drive motor (20) of the second cutting disc block (42); and - determining a failure of the 2-shaft grinder (1) based on the detected first and second power inflows.

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