TWI836603B - rotor - Google Patents

Abstract

The invention provides a rotor for a stirring ball mill. The rotor has a multi-part metal base frame, a plurality of grinding tools arranged on the base frame and at least one, preferably a plurality of non-metallic housing elements. The at least one housing element is preferably detachably mountable to the base frame and is designed such that the surface of the base frame is substantially covered or wrapped by the housing element. In addition, a grinding disc assembly for a rotor, a housing element and a metal base frame for the rotor are also provided.

Description

Rotor

The present invention relates to a rotor, in particular to a rotor used in a metal-free processing zone of a stirring ball mill.

Due to the growing demand for batteries, the production of cathode active materials or anode active materials is becoming increasingly important. Active materials such as lithium iron phosphate (LFP), lithium nickel manganese cobalt oxide (NCM), silicon (Si) have to be ground using a stirred ball mill (RWKM) with a metal-free processing zone. The volume of the processing zone can exceed 60 liters. The processing zone has a rotor and a cooled stator. Since water cooling is required, the stator is usually made of silicon carbide (SiC), while the rotor, which does not require separate cooling, can be freely selected. If the product to be ground is water-based, rotors made of low-cost plastics such as polyurethane (PU) are generally used. If the product is a solvent-based formulation, rotors made of ceramic materials such as zirconium oxide (ZrO) are used.

However, ceramic rotors in particular are expensive, heavy and susceptible to shock when installed in the RWKM. In addition, the coefficient of thermal expansion of some ceramics is different from that of steel, making the design and manufacture of rotors complex and expensive. Rotors made purely of plastic or metal rotors coated with plastic are not resistant to solvents and are therefore also unsuitable for many products. In addition, the rigidity of the rotor is also important to prevent the component from deforming during operation.

Documents such as CN205304429U, DE10064828B4, CN210279354U, CN204134699U, CN210357393U and CN204724256U are related to prior art related to the present invention.

Therefore, the object of the present invention is to overcome the disadvantages of the previous rotors. This is achieved by the features described below. The invention is defined in the independent claims. The dependent claims describe the preferred embodiments.

The present invention provides a rotor for a stirred ball mill. The rotor has a metal base frame composed of multiple parts, multiple grinding tools arranged on the base frame, and at least one, preferably multiple non-metallic shell elements. The at least one shell element can be detachably mounted on the base frame, and is designed so that the surface of the base frame is substantially covered or coated by the shell element.

At least one part of the base frame can be formed by one or more grinding discs arranged side by side and/or by spacer bushings and/or guide cages arranged between every two adjacent grinding discs.

During operation, the rotor should be arranged in the grinding chamber of the stirred ball mill containing the materials to be ground and grinding aids. The surfaces of the base frame covered by the shell elements are those that are not covered during the use of the rotor. The surface of the object will come into contact with the material to be ground and the grinding aids.

The at least one housing element is preferably provided with an opening through which the grinding tool can pass.

A part of the rotor is in particular a cylindrical drive part, wherein a metal base frame forms a grinding disc frame part in the area of the drive part, which is formed by one or more metal grinding discs arranged at a distance from each other, wherein each grinding disc has two side surfaces, a through hole formed in the center of the grinding disc for accommodating a stirring shaft for driving the rotor, and an outer peripheral surface, wherein a plurality of grinding tools are arranged on the outer peripheral surface, wherein the part of the housing element for covering the grinding disc is always formed by two half shells made of plastic, which surround at least the side surfaces and the outer peripheral surface of the grinding disc.

Furthermore, another part of the rotor can form a cylindrical cage part, wherein the metal base frame forms an air guide cage in the area of the cage part, which air guide cage consists of metal longitudinal struts spaced apart from each other in the circumferential direction. Formed, the longitudinal struts extend in the direction of the rotation axis of the rotor, wherein longitudinal gaps are formed between the longitudinal struts. A plurality of grinding wheels may be arranged on the longitudinal struts, wherein the portion of the housing element covering the longitudinal struts is formed by a housing element covering the portion of the longitudinal struts between the grinding wheels.

The longitudinal struts of the cage part can be connected to the grinding disc of the driving part adjacent to the cage part through pull rods/push rods respectively.

One end of the base frame can be formed in the region of the cage part by a metallic annular end element which is connected to the longitudinal strut. The housing element for covering the end element can be formed by an arcuate element fixed to the end element on both sides.

The housing element can be connected to the base frame in a form-fitting manner by means of a snap connection, or preferably is screwed to the base frame.

The housing element is made in particular from a thermoplastic, thermosetting plastic or elastomer, such as PA, PE, PU, NBR, or fiber-reinforced plastic. The metal base frame can be made of stainless steel, and the abrasive tool can be made of ceramics, preferably zirconia or silicon carbide, or plastic.

The housing components can be manufactured using cutting methods such as milling, turning or drilling, or using 3D printing methods or as injection molded parts.

The invention further provides a grinding disk assembly for a rotor, in particular for a rotor according to the invention as described above. The assembly has a metal grinding plate with two sides, a through hole formed in the center of the plate body to accommodate the agitator, and an outer peripheral surface. In addition, there are a plurality of grinding tools arranged on the outer peripheral surface and protruding radially outward from the outer peripheral surface, and two half-shells made of plastic, which are used to cover the grinding disc and be fixed on the metal grinding disc 4 superior. The half shell surrounds at least the sides and outer peripheral surface of the grinding disc.

The invention also relates to a housing element configured for a rotor according to the invention or a grinding disc assembly according to the invention.

Another aspect of the invention is a metal base frame for a rotor, in particular for a rotor according to the invention. The base frame has: a grinding disc part with a plurality of grinding discs arranged side by side and spacing bushings arranged between every two adjacent grinding discs; a flow guide cage consisting of a rotating shaft spaced apart from each other in the circumferential direction and on the rotation axis of the rotor. Metal longitudinal struts extending in the direction, longitudinal gaps arranged between the longitudinal struts, and metallic annular end elements connected to the longitudinal struts are formed; and a plurality of stabilizing elements are arranged between the grinding discs and between the grinding discs and the ends. between components.

The operating principle of a stirred ball mill is known and will not be described in detail here. A stirred ball mill usually has a stator and a rotor, wherein, depending on the specific design, grinding tools in the form of pins or bumps can be provided on the rotor. In addition, grinding tools can be mounted on the inner wall of the stator, which are arranged offset in the axial direction relative to the rotor grinding tools so that the rotor can rotate. A grinding chamber is provided between the stator and the rotor, in which the material to be ground is dispersed or ground when the rotor rotates around the rotation axis (central longitudinal axis). Grinding aids are often used in this process, for example in the form of ceramic balls located in the grinding chamber.

A screen is installed on the discharge end to prevent grinding aids or larger solids from entering the discharge and contaminating the product. The rotor is at least partially mounted around the screen, that is, radially outside. In order to ensure that the product flows through the screen, the rotor around the screen is usually formed as a guide cage. This cage prevents grinding aids from accumulating on the screen and hindering the discharge of ground materials. This cage shape is usually achieved by multiple rods in the axial direction, which are connected through circular parts to form a hollow cylinder that allows materials to pass. The drive side shown on the right side of Figure 1 is connected to the drive shaft.

Figure 1 shows an exemplary base frame 1 of a rotor according to the present disclosure. A rotor with a base frame as described here can be used in particular, but not exclusively, in horizontal agitator ball mills, ie mills with a horizontal axis of rotation. The base frame 1 is composed of multiple parts. In particular, the base frame 1 can be designed as an essentially hollow cylindrical object.

In Fig. 1 can be seen the flow guide cage 121, which, as mentioned above, is formed by a plurality of longitudinal struts 6 spaced apart from each other in the circumferential direction, and these longitudinal struts are respectively connected at both ends by Ring end elements 7 or circular elements are connected to each other. Thus, a longitudinal gap 61 is formed between the longitudinal struts 6 and can be used to discharge the materials or products to be ground. During operation, the screen is installed inside the guide cage 121, that is, located radially inward (not shown). The flow guide cage 121 can also adopt other designs that allow the material to be ground to pass. The drive side portion on the right side of the figure is formed from one or more grinding discs 4 as the grinding disc frame portion 111 . The grinding discs can be separated from each other by spacing bushings 5 to ensure that the distance between the grinding discs 4 or between the discharge side grinding discs 4 and the flow guide cage 121 is consistent. The last spacer bushing can also be formed as part of the flow guide cage 121 .

The flow guide cage 121 of the base frame 1 and the grinding plate frame part 111 (and optionally the spacer bushing 5) can be made of metal, such as stainless steel. The metal base frame 1 is the supporting structure of the rotor, giving the rotor the necessary stability and allowing efficient transmission of torque from the drive shaft, especially to the grinding tools that can be fixed to the base frame 1 . The base frame 1 shown in Figure 1 is shown in Figure 2 after being equipped with grinding tools 2. The grinding tools are fixed radially on the longitudinal support rod 6 at the guide cage 121, and are fixed along the longitudinal direction in the grinding plate part 111. Radially fixed on the grinding disc 4. In one embodiment, the grinding tool 2 is fixed with screws. As an alternative, the grinding tool 2 itself can have an external thread and be mounted to the base frame 1 by means of the external thread, that is, to the longitudinal strut 6 of the guide cage 12 or to the grinding plate 4 . The abrasive tool can be made of plastic or ceramic such as zirconium oxide (ZrO ₂ ) or silicon carbide (SiC). In addition, the grinding tool 2 itself may also have a basic structure made of, for example, metal and coated, encapsulated or coated. The shape of the grinding tool 2 is cubic in Figure 2 . The grinding tool 2 stirs and activates the grinding aid, and may also be circular, trapezoidal or mushroom-shaped, for example, and have functional surfaces to guide the grinding aid to the desired direction axially or radially. Among them, the grinding discs 4 can be installed and replaced one by one, thereby ensuring a modular structure.

When processing certain materials, it should be ensured that no metal chips get into the product. For example, in the case of LFP, a cathodic active material used in the manufacture of batteries, the processing area should remain metal-free. In other words, no metal chips should get into the grinding chamber. To this end, the metal surfaces of the base frame 1 that come into contact with the material to be ground or the grinding aid in the grinding chamber should be covered or coated, i.e. wear-protected. This is achieved by at least one housing element, preferably a plurality of housing elements 3, as shown in FIG. 3 .

In the simplest embodiment, the base frame as shown in FIG1 may be provided with an integral cylindrical shell element, which can be sleeved on the base frame 1 so that the surface of the base frame 1 is covered, wherein an opening may be provided so that the mold 2 can be fixed to the base frame after the shell element is sleeved. However, as shown in FIG3, it is preferred to provide a plurality of shell elements 3, which match the surface of the base frame 1 and can cover or envelop the surface as completely as possible. The shell element 3 is non-metallic and can be removably (or connectably) fixed to the base frame 1. The fixing can be achieved by a screw connection, a snap connection, a clamping connection or a similar connection. Thus, the rotor and the base frame 1 each have the same retainer portion 12 (or the guide retainer 121) and the drive portion 11 (or the grinding disc frame portion 111). These portions refer to the axial portions along the rotation axis.

The different geometries of the cage part 12 and the drive part 11 are taken into account when designing the housing element 3, i.e. the longitudinal support rod 6 and the annular end element 7 or the grinding plate 4 are covered by a precisely fitting housing element 3. Preferably, a plurality of housing elements 3 are arranged on the grinding plate 4 and the longitudinal support rod 6 or on the one-piece or composite circular end element 7, which surround the relevant components or sections of the base body 1. For example, the longitudinal support rod 6 of the guide cage 121 can be covered by a plurality of housing elements 3, which are connected to each other or to the base body 1 itself by means of a screw connection. The annular end element 7 can be covered or covered by an arched housing element 3. In the case of a snap-on or clamping connection, in order not to cause plastic deformation and thereby damage the shell element 3, the different expansion degrees of the shell element and the structure located thereunder when heated should be taken into account.

The housing element 3 may be formed of thermoplastic or thermosetting plastic, or may be formed of an elastomer such as PA, PE, PU, NBR, or the like, or may be formed of fiber-reinforced plastic. Furthermore, depending on the material selected, the housing element 3 can be produced by cutting (eg milling, turning or drilling) or 3D printing, or can be produced as an injection molded part. As an alternative, the housing parts can also be coated, encapsulated or spray-coated.

It should be noted that it is preferred to cover the larger metal surfaces of the base frame 1 or to keep them substantially away from the abrasive material flow in order to avoid metal debris, i.e. wear, there. Since the screw head is preferably a countersunk head in the case of a screw connection of the abrasive tool 2 and/or the housing element 3, there is no high degree of metal wear there. As an alternative, a plastic screw or a ceramic screw can be used, or the screw can be placed inside. As an alternative, the abrasive tool 2 can also be connected to the base frame 1 by bonding or clamping, so that the connection does not come into contact with the abrasive material flow.

The shell element 3 may have a groove or opening 31 for the mold 2 to pass through. The shell element 3 may be further divided into a plurality of shell elements, which surround the base frame 1 and the mold 2 after being assembled.

Gaps may be provided between the housing elements 3 to allow thermal expansion without plastic deformation during operation. In addition, these gaps allow water expansion without plastic deformation. It may also be advantageous to provide seals between the housing elements 3 , between the housing elements 3 and the grinding tool 2 and/or between the housing elements 3 and the base frame 1 .

FIG. 4 shows a lateral section through a base frame 1 in which the housing element 3 described with reference to FIG. 3 is installed. FIG. 4 also shows in dotted lines the aforementioned rotational axis that is not clearly shown in FIGS. 1 to 3 .

Figure 5a is an exploded view of the grinding disc 4 with the grinding tool 2 and the housing element 3 according to the present disclosure. The grinding plate 4 is made of metal, such as stainless steel, and has two side surfaces 41 , a through hole 42 formed in the center of the grinding plate 4 to accommodate a stirring shaft or a driving shaft, and an outer peripheral surface 43 . The grinding plate 4 may have one or more bores for receiving screws. In addition, grooves and/or reinforcing ribs can also be provided. A plurality of grinding tools 2 protruding radially outward from the outer peripheral surface 43 are mounted on the outer peripheral surface. The housing element 3 surrounds at least the side surface 41 and the outer peripheral surface 43 , except for the grinding tool 2 . It can be seen from the exploded view that in this example, the grinding tool 2 and the housing component 3 are respectively fixed to the grinding plate 4 through screw connections.

FIG. 5 b shows the assembly state of the grinding disc 4 with the housing element 3 and the grinding tool 2. The grinding disc 4 can be provided separately as a spare part, whether with or without the housing element 3 and/or the grinding tool 2, and as mentioned above, can be used to form the base frame 1 of the rotor in a modular manner by means of the spacer sleeve 5. In addition, individual grinding discs 4, grinding tools 2 or housing elements 4 can also be replaced according to the wear condition.

That is, the housing element 3 of the grinding disc assembly shown in the figure has two plastic half shells for covering the grinding discs. The half shells are fixed to the metal grinding disc 4, respectively, wherein the half shells at least surround the side surface and the outer peripheral surface of the grinding disc 4. The half shells thus form the housing element 3. However, the housing element 3 can also be subdivided in other ways and can be composed of more than two parts, but the condition is that the metal surface that would come into contact with the ground material and the grinding aid without the covering is basically covered or coated.

Figure 6 shows another embodiment of the metal base frame 1 for the rotor as shown in figure 1 . The embodiment according to FIG. 6 furthermore has stabilizing elements 8 which, for example in the form of rods, connect the grinding disc 4 to the flow guide cage 121 . The stabilizing elements 8 are represented in FIG. 6 as round rods which are arranged between the grinding discs 4 and between the grinding discs 4 and the flow guide cage 121 or its end elements 7 .

These stabilizing elements 8 can supplement the base frame 1 .

The stabilizing element 8 can be arranged as a single short element between the grinding discs 4 , or can be designed as a continuous rod passing through the grinding discs 4 , optionally with separating or spacing elements between the grinding discs 4 . The stabilizing element 8 is preferably arranged near the outer circumference of the grinding disc 4 . The stabilizing element 8 can also adopt a composite design, for example, consisting of a tie rod and a pressure sleeve. These stabilizing elements can be fixed on the base frame 1 with screws and nuts using corresponding threads and holes.

The stabilizing element 8 has the function of stabilizing and reinforcing the base frame 1 . This will reduce the deformation of the rotor under the action of external forces such as gravity. Another advantage is that the distance from the rotating cage to the stationary screen located inside the cage can be chosen to be very small. When the distance from the screen to the cage is small, the grinding aid will be more easily retained by the screen. This enables the machine to have a higher product throughput rate and efficiency.

That is, the stabilizing element 8 can play the role of a pull rod or a push rod, thereby achieving a higher design stiffness and thus achieving low deflection of the drive shaft in horizontal operation.

Therefore, such a base frame 1 with a stabilizing element 8 is also an aspect of the present disclosure, wherein such a special design makes it possible to provide a lightweight base frame 1, which is particularly advantageous in combination with the housing of a large agitator ball mill (e.g., with a rotor diameter of 40 cm or more).

The present disclosure further includes a housing element 3 or housing element assembly for the rotor and/or grinding disc 4 and/or grinding disc assembly as described above. Such a housing element 3 or a housing element assembly can be mounted on an existing base frame (eg a base frame according to the present disclosure) to cover a metal surface, or can replace worn housing elements.

In addition, the present disclosure also includes a use of a housing element 3 or a housing element assembly in the rotor and/or grinding disc 4 and/or grinding disc assembly as described above.

In summary, the present invention can provide a modular rotor for a stirred ball mill, which can also be used in a metal-free processing area. In addition, each housing element, grinding tool or grinding disc can be replaced individually according to the wear situation. The metal parts (i.e. the base frame or skeleton of the rotor, including the retaining frame, grinding disc and (if applicable) the spacer bushing and/or stabilizing element) will not be worn under the protection of the coating, thereby realizing metal-free crushing of the product.

The housing is shaped so that it forms a cylinder, which creates an annular grinding gap between the rotor and the grinding container. The housing is made of a wear-resistant material such as plastic or ceramic. Furthermore, the housing can be screwed to the metal structure, which makes it easy to replace in the event of wear. However, the housing can also be fixed in a form-fitting manner by means of a snap connection.

The housing components are only lightly loaded because the grinding tool conducts the forces onto the supporting structure, the base frame. The pull rod/push rod connects the disc body and the cage on a large diameter and reinforces the structure, so that the deflection of the shaft body is very small, so that it is possible to select a very small distance from the cage to the screen.

The hybrid design of metal, plastic and ceramic also ensures that the overall weight of the rotor is low while maintaining maximum rigidity. This also helps achieve low deflection of the drive shaft or rotor in horizontal operation and reduces the distance from the cage to the screen.

Although the present invention has been illustrated and described in detail with the aid of the accompanying drawings and related descriptions, the drawings and the detailed description should be understood as illustrative and exemplary rather than limiting of the present invention. It is understood that those with ordinary knowledge in the relevant fields can make modifications and changes without departing from the scope of the appended patent application. In particular, the invention also encompasses embodiments having any combination of the features mentioned or illustrated above with respect to different aspects and/or embodiments.

The invention also includes individual features which are illustrated in the accompanying drawings in conjunction with other features and/or which are not mentioned above.

Furthermore, the term "comprising" and its derivatives do not exclude other elements or steps. Likewise, the indefinite article "a" or "an" and its derivatives do not exclude plurality. The functions of multiple features listed in the patent application can be implemented by one unit. Terms related to properties or values such as "substantially", "approximately", and "approximately" also define the property or value particularly precisely. All symbols in the scope of the patent application should not be construed as limitations on the scope of the patent application.

1: Base frame 2:Abrasive tools 3: Shell components 4: Millstone 5: Spacer bushing 6:Longitudinal support 7: End elements 8: Stabilizing element 11: Drive part 12: Cage part 41:Side 42:Through hole 43: Outer peripheral surface 61: Longitudinal gap 111: Grindstone frame part 121: guide cage

The invention will be further described below with reference to the accompanying drawings. in: [Fig. 1] is an exemplary view of a metal base frame of a rotor according to the present disclosure, [Figure 2] is an exemplary view of the base frame in Figure 1 after being equipped with a grinding tool. [Fig. 3] is a perspective view of a rotor with a housing element installed according to an embodiment, [Fig. 4] is a side cross-sectional view of the rotor according to the present disclosure, [Fig. 5a] and [Fig. 5b] are views of the disk body according to the present disclosure, [Fig. 6] is an exemplary view of the rotor metal base frame with stabilizing elements.

1: Base frame

4: Millstone

5: Spacer bushing

6: Longitudinal support rod

7: End elements

61: Longitudinal gap

111: Grinding disc frame part

121: guide cage

Claims (14)

A rotor for a stirring ball mill, comprising: - a metal base frame (1) composed of multiple parts, - a plurality of grinding tools (2) arranged on the base frame (1), and - at least one non-metallic shell element (3), wherein the at least one shell element (3) is designed so that the surface of the base frame (1) is substantially covered or coated by the shell element (3), wherein a part of the rotor forms a cylindrical driving part (11), wherein the metal base frame (1) forms a grinding disc frame part (111) in the area of the driving part (11), and the grinding disc frame part is composed of one or more metal grinding tools arranged separately from each other. The invention relates to a grinding disc (4), wherein each of the grinding discs (4) has two side surfaces, a through hole formed in the center of the grinding disc for accommodating a stirring shaft for driving the rotor, and an outer peripheral surface, wherein the plurality of grinding tools (2) are arranged on the outer peripheral surface, wherein the portion of the housing element (3) for covering the grinding discs (4) is formed by two half shells made of plastic, and the two half shells at least surround the two side surfaces and the outer peripheral surface of the grinding disc (4). A rotor as described in claim 1, wherein the base frame (1) further comprises a flow guide retainer (112) adjacent to the grinding disc frame portion (111). The rotor as described in claim 1, wherein the rotor is arranged in a grinding chamber of a stirred ball mill containing a material to be ground and a grinding aid during operation, wherein the surfaces of the base frame (1) covered by the shell elements (3) are those surfaces that will come into contact with the material to be ground and the grinding aid during the use of the rotor if there is no covering. A rotor as described in any one of the aforementioned claims 1-3, wherein an opening (31) is provided on the at least one shell element (3) for the molds (2) to pass through. The rotor according to claim 2, wherein a part of the rotor forms a cylindrical cage part (12), and wherein the metal base frame (1) forms the flow guide cage in the area of the cage part (12) (121), the flow guide cage is formed by metal longitudinal struts (6) spaced apart from each other in the circumferential direction, which extend in the direction of the rotation axis of the rotor, wherein in the longitudinal struts (6 ), a plurality of grinding tools (2) are arranged on the longitudinal struts (6), and the housing element (3) is used to cover the longitudinal struts (6) is formed by a housing element (3) covering the longitudinal strut portion between the grinding tools (2). The rotor as described in claim 5, wherein the longitudinal support rod (6) of the guide retainer (121) is connected to the grinding disc (4) adjacent to the guide retainer (121) of the driving part (11) through a pull rod/push rod. A rotor as claimed in claim 5 or 6, wherein one end of the base frame (1) is formed by a metal annular end element (7) in the region of the retaining frame portion (12), the end element being connected to the longitudinal support rods (6), and the shell element (3) for covering the end element is formed by an arched element fixed to the end element on both sides. The rotor according to claim 1, wherein the base frame (1) further has a plurality of stabilizing elements (8), which are arranged between the grinding discs (4) or pass through the grinding discs (4). The rotor as described in claim 1, wherein the shell elements (3) are connected to the base frame (1) in a form-fitting manner by snap-fit connection, or preferably, the shell elements (3) are screwed to the base frame (1). The rotor of claim 1, wherein the housing elements (3) are made of thermoplastic plastic, thermosetting plastic or elastomer, such as PA, PE, PU, NBR, or fiber-reinforced plastic, and/or, wherein the The metal base frame (1) is made of stainless steel, and/or the grinding tools (2) are made of ceramics, preferably zirconia or silicon carbide, or plastic. The rotor as described in claim 1, wherein the shell elements (3) are manufactured by cutting, such as milling, turning or drilling, or by 3D printing, or are manufactured as injection molded parts. A grinding disc assembly for a rotor, especially a grinding disc assembly for a rotor as described in any one of the preceding claims 1-11, including: a metal grinding disc (4) with two sides formed on the disc There is a through hole in the center of the body for accommodating the agitator, as well as an outer peripheral surface, a plurality of grinding tools (2) arranged on the outer peripheral surface and extending radially outward from the outer peripheral surface, and two semi-finished parts made of plastic. Shell, the two half-shells are used to cover the grinding plate (4) and be fixed on the metal grinding plate (4), wherein the two half-shells surround at least the two sides and the outer peripheral surface of the grinding plate (4). The grinding plate assembly as claimed in claim 12, wherein after the two half-shells surround at least the two sides and the outer peripheral surface of the grinding plate (4), there is an opening (31) for the grinding tools (2) to pass through. ) is provided on the two half-shells. A metal base for a rotor, in particular a metal base for a rotor as described in any one of claims 1 to 11, comprising: a grinding disc portion (111) having a plurality of grinding discs (4) arranged side by side and a spacer sleeve (5) arranged between every two adjacent grinding discs (4); a flow guide retainer (112) consisting of circumferentially spaced apart from each other and arranged in the circumferential direction; The rotor is formed of metal longitudinal support rods (6) extending in the direction of the rotation axis and metal annular end elements (7) connected to the longitudinal support rods (6), wherein longitudinal gaps (61) are formed between the longitudinal support rods (6), and a plurality of stabilizing elements (8) are arranged between the grinding discs (4) and between the grinding discs 4 and the end elements (7).