Centrifugal screw, solid bowl centrifuge, and method for producing a centrifugal screw

Abstract

The invention relates to a centrifugal screw having a screw hub (10) that has at least one longitudinal portion with an open wall structure. The longitudinal portion has at least two hub portions (20) that are connected together, each monolithically formed, and each monolithically formed hub portion (20) has a circumferential wall (21) and two end faces (33, 34), and a plurality of openings (32) are formed in the circumferential wall. According to the invention, at least two hub portions (20) that rest against each other are connected together at least partly, preferably completely, at the end faces (33, 34) resting against each other by means of a positively locking connection and by means of an integrally bonded connection, in particular by means of a welded connection.

Description

[0001] Centrifuge screw, solid bowl screw centrifuge and method for producing a centrifuge screw

[0002] Description

[0003] The invention relates to a centrifuge screw having a screw hub according to one of claims 1 or 4 or 5 or 6 or 8 or 11. Furthermore, the invention relates to a solid bowl screw centrifuge according to claim 23. Furthermore, the invention relates to a method for producing a centrifuge screw, in particular a centrifuge screw according to the invention, according to claim 24.

[0004] Solid bowl centrifuges are characterized by a bowl with a closed or solid bowl. The bowl rotates at high speed, allowing a multiphase mixture contained within the bowl to be separated into at least one heavy phase and one light phase. The heavy phase is usually a solid phase, which is removed from the bowl by a screw, i.e., a centrifuge screw. For this purpose, the screw is mounted within the bowl so it can rotate relative to the bowl and has a screw flight. The screw flight is attached directly or indirectly to the screw hub and surrounds it in a spiral configuration.

[0005] The screw flight sweeps along the inside or inner surface of the drum, thus conveying the heavy phase material to an axial end of the drum. At the end of the drum, the heavy phase material is discharged, for example, from a discharge cone. The multiphase mixture to be clarified is therefore primarily located between the inside of the drum and the screw hub.

[0006] In certain solid-bowl screw centrifuges, a large pond depth is desired, particularly for treatment-related reasons. At the same time, however, the pond depth is limited by the diameter of the screw hub and the resulting buoyancy and sedimentation effects of the mixture to be clarified or the light phase. Furthermore, there is a constant effort to design a screw hub with sufficient or increased rigidity.

[0007] The pond depth can be increased by making the screw hub particularly permeable to media, but this may weaken the structure of the screw hub.

[0008] Furthermore, it is a constant effort to avoid components in connection with screw hubs that negatively influence the flow characteristics inside and outside of a screw hub.

[0009] The invention is therefore based on the object of providing a centrifuge screw, in particular a centrifuge screw for a solid bowl screw centrifuge, which has increased rigidity and at the same time improved flow properties due to an improved structural design.

[0010] At the same time, a modular design of the centrifuge screw should be made possible so that the size, in particular the longitudinal extent, of the centrifuge screw can be designed according to a modular principle.

[0011] Furthermore, the invention is based on the object of providing a further developed solid bowl screw centrifuge.

[0012] Furthermore, it is an object of the present invention to provide a simplified method for producing a centrifuge screw, in particular a further developed one.

[0013] According to the invention, this object is achieved with regard to the centrifuge screw by the subject matter of claim 1 or 4 or 5 or 6 or 8 or 11.

[0014] With regard to the solid bowl screw centrifuge, the above-mentioned object is achieved by the subject matter of claim 22.

[0015] With regard to the method for producing a centrifuge screw, the above-mentioned object is achieved by the subject matter of claim 24. The subclaims comprise at least expedient embodiments and further developments.

[0016] Specifically, the object is achieved in a first main aspect of the invention by a centrifuge screw having a screw hub, wherein the screw hub has at least one longitudinal section with an open wall structure, wherein the longitudinal section has at least two interconnected, each monolithically formed hub sections, wherein each monolithically formed hub section has a peripheral wall and two end faces and a plurality of openings are formed in the peripheral wall.

[0017] According to the first main aspect of the invention, at least two adjacent hub sections are connected to one another at least in sections, preferably completely, at the adjacent end faces by means of a positive connection and by means of a material connection, in particular by means of a welded connection.

[0018] The centrifuge screw according to the first main aspect of the invention combines several advantages due to the novel design of at least interconnected hub sections, with at least two of the connected hub sections being monolithically formed. Due to the monolithic design, the hub section exhibits particularly high rigidity. At the same time, a great pond depth can be achieved due to the large number of openings.

[0019] Since the at least two adjacent hub sections are connected at least in sections both by means of a positive connection and by means of a material connection, a particularly good connection is achieved between the at least two adjacent hub sections.

[0020] Secondly, such a design of a centrifuge screw facilitates the production of the centrifuge screw, in particular the production of the screw hub. In a first step of a joining or manufacturing process, a positive connection of the at least two adjacent hub sections can be made. This is followed by the production of the integral connection, in particular a welded connection, in a second joining step.

[0021] Due to the positive connection, a preliminary adjustment of the adjacent hub sections can be performed. In this pre-adjusted state, the additional material connection, particularly a welded joint, can then be established.

[0022] A positive connection is understood in particular to be a connection of at least two monolithically shaped hub sections that blocks the relative movement of the at least two monolithically shaped hub sections to one another in at least one direction. Depending on the specific design of the positive connection, the at least one direction to be blocked can be different directions, for example, the direction of rotation. A positive connection is preferably understood to be a connection of at least two monolithically shaped hub sections that blocks the relative movement of the at least two monolithically shaped hub sections to one another in at least one direction.In a further preferred embodiment of the invention, a positive connection is understood to be a connection of at least two monolithically formed hub sections that blocks the relative movement of the at least two monolithically formed hub sections to one another in at least two directions. Depending on the specific design of the positive connection, the at least two directions to be blocked can be different directions, including, for example, the direction of rotation.

[0023] In one embodiment of the invention, the positive connection is formed by projections formed complementarily to one another on the adjoining end faces of two monolithically formed hub sections.

[0024] In other words, at least one first projection is formed on a first end face of a first monolithically formed hub portion. A second projection is formed on a first end face of a second monolithically formed hub portion, which abuts the first monolithically formed hub portion. The first projection is complementary to the second projection, so that the two abutting hub portions are connected or connectable in a form-fitting manner.

[0025] For example, the first projection can be designed as a step-like projection protruding from the end face. The second projection, however, can be designed as a nose-like projection protruding from the end face. The projections designed in this way can form a positive connection by the two end faces abutting against one another. It is possible for the step-like projection and / or the nose-like projection to be formed over the entire circumference of the end face.

[0026] Furthermore, it is possible that the first projection and / or the second projection is formed only in sections.

[0027] Furthermore, it is possible for a plurality of step-like projections to be formed on the first end face. Preferably, especially in this case, a plurality of nose-like projections are formed on a first end face of the second hub portion. In such a case, the nose-like and step-like projections can be configured to engage one another in such a way that a positive connection can be established.

[0028] When forming a shoulder-like projection and / or nose-like projection that extends over the entire front side, the design advantage is that this projection / these projections can be manufactured extremely easily and, at the same time, an extremely stable form fit can be formed between two adjacent or mutually adjacent hub sections.

[0029] In a further embodiment of the connection, the positive connection can be formed, for example, by locking elements. At least one locking element of the first type can be formed on a first end face of a first hub section, and at least one locking element of the second type can be formed on a first end face of a second hub section, which is to be connected to or is connected to the first hub section. The at least one locking element of the first type and the at least one locking element of the second type are designed to complement one another, so that the two locking elements (of the first and second type) can form a positive connection.

[0030] Preferably, a hub section has a connecting element, in particular at least one projection, with a first shape on the first end face, whereas at least one connecting element, in particular at least one projection, with a second shape is formed on the second end face of the hub section. By forming connecting elements, in particular projections, on both end faces of a hub section, which are designed to be complementary to one another in such a way that the connecting element, in particular the projection, of a first shape creates or can create a positive connection with a connecting element, in particular a projection, of a second shape, it is possible for several similarly designed, monolithically shaped hub sections to be connected to one another.

[0031] In a further embodiment of the invention, it is possible for only the end face of a monolithically shaped hub section to have a connecting element, in particular a projection, which is to be connected to another monolithically shaped hub section. It is possible, for example, for an end face of a monolithically shaped hub section that is to be connected to a different type of hub section and / or an end part of the screw hub and / or a bearing section and / or a solids discharge section to have no connecting element, in particular no projection.

[0032] In a further embodiment of the invention, it is possible for the shape of the positive connection of at least two adjacent hub sections and / or sections of the adjacent end faces to form a groove, wherein the material connection, in particular at least one weld seam section, is formed in the groove.

[0033] In this case, the groove forms a type of welding aid, so that the process for creating a material-to-material connection, in particular a welded connection, can be simplified. The formation of a groove can form a type of marker in an automated welding process, indicating at which point on the hub sections to be materially joined a material-to-material connection section, in particular at least one weld seam section, is to be formed.

[0034] In other words, the groove can also be referred to as a recess or cutout which is formed on the outside of the worm hub structure which has previously been positively connected to one another when the hub sections are in contact with one another.

[0035] Forming a positive connection between at least two monolithically formed hub sections by forming projections is particularly suitable for the formation of end faces that have a continuous end face. The end faces can be annular or essentially annular. Forming projections is also suitable for inclined or spiral-shaped end faces.

[0036] Furthermore, it is possible for a plurality of monolithically shaped hub sections, which at least partially form a worm hub, to be arranged and configured in a complementary manner to one another, with overlapping and / or oblique and / or spiral-shaped end faces, such that they are designed to engage one another, so that the positive connection of at least two adjacent hub sections occurs at least partially, preferably completely, at the adjacent end faces due to the shape of the end faces. In this case, a particularly advantageous connection of adjacent or juxtaposed hub sections can be realized, both with regard to the rigidity of the worm hub structure and with regard to the positive connection as such.

[0037] It is possible for at least one end face of a monolithically shaped hub section to be formed by end faces of web elements. The web elements are preferably arranged relative to one another in such a way that prongs, in particular triangular ones, are formed, which can be recognized as triangular or prong-shaped elements in the longitudinal direction of the hub section. Preferably, at least two web elements delimit a triangular opening, at least in sections. In other words, at least two web elements of the end face of a monolithically shaped hub section form two of three sides of a triangular opening. It is possible for a front face of a hub section to have a plurality of prongs, in particular at least three prongs, preferably at least four prongs.

[0038] Two hub sections arranged next to one another can be designed to be complementary to one another in such a way that both end sections have the same number of teeth, so that the teeth each engage in free spaces formed between the teeth of the adjacent hub section.

[0039] At least one end face of a monolithically formed hub section can be formed from multiple end face sections. Multiple end face sections, which are separated from one another, for example, by corners and / or edges and / or radii, or which form individual end face sections by corners and / or edges and / or radii, can collectively form one end face of a monolithically formed hub section.

[0040] The end face sections can, for example, be formed obliquely to the longitudinal axis of the monolithically formed hub section, so that when the end face sections lie against one another, they can form a positive connection with end face sections of another monolithically formed hub section.

[0041] Particularly in embodiments of the invention that comprise at least one connection of monolithically formed hub sections with adjacent end faces formed obliquely to the longitudinal axis, the end faces of the monolithically formed hub sections, which form an end face of the longitudinal section of the open wall structure of the screw hub, can be formed perpendicular to the longitudinal axis. This enables the formation of a straight end of the longitudinal section, so that the longitudinal section can be easily connected to other sections and / or components of the screw hub.

[0042] In particular, depending on the specific positioning of a monolithically formed hub section, it is possible to form a first end face oblique to the longitudinal axis and a further end face perpendicular to the longitudinal axis. Furthermore, it is possible for at least one end face section, in particular a plurality of end face sections, of at least one end side to be curved, wherein the curvature can be concave and / or convex in relation to the longitudinal axis of the monolithically formed hub section. The curvature of the at least one end face section, preferably of all end face sections, is preferably complementary to the curvature of an end face section, in particular of all end face sections, of an adjacent monolithically formed hub section, so that the at least two adjacent hub sections can form a particularly good form-fitting connection.

[0043] In a further embodiment of the invention, it is possible for the end face of a monolithically formed hub section to be formed from two end face sections, wherein a first end face section extends spirally relative to the longitudinal axis of the monolithically formed hub section or around the longitudinal axis. The ends of the spiral end face section can be connected, for example, by means of a second end face section that extends linearly or slightly spirally compared to the first end face section.

[0044] Even when designing a monolithically shaped hub section with such end face sections, it is possible for the two end faces of a hub section to be designed to be complementary to one another, so that several such hub sections can be connected to one another with their end faces abutting one another.

[0045] A further second main aspect of the invention relates to a centrifuge screw having a screw hub which has at least one longitudinal section with an open wall structure, wherein the longitudinal section has at least two interconnected, respectively monolithically formed hub sections, wherein each monolithically formed hub section has a peripheral wall and two end faces and a plurality of openings are formed in the peripheral wall, wherein according to the invention at least one of the monolithically formed hub sections, preferably all monolithically formed hub sections, has / have at least one screw flight root and / or one screw flight.With regard to the centrifuge screw according to the second main aspect of the invention, it should be noted that all features, explanations, and embodiments previously mentioned in connection with the centrifuge screw according to the first main aspect of the invention can also be applied to a centrifuge screw according to the second main aspect of the invention. This results in similar or identical advantages as those already stated in connection with the centrifuge screw according to the first main aspect of the invention.

[0046] According to the second main aspect of the invention, at least one monolithically formed hub section can have at least one worm screw base and / or one worm screw. In other words, the monolithically formed hub section can already have a worm screw base and / or one worm screw in its monolithic basic structure.

[0047] In such a case, the worm screw root and / or the worm screw blade is part of the monolithic structure of the hub section. In such a case, the worm screw root and / or the worm screw blade is not applied to the hub section in a separate manufacturing process. In other words, the worm screw root and / or the worm screw blade is part of the monolithic basic structure of the hub section. If the monolithically formed hub section has only one worm screw root, additional sections of a worm screw blade can be applied in a separate process.

[0048] For example, the screw spiral blade can be welded onto the screw spiral foot.

[0049] In other words, the worm helix root and / or the worm helix are a structural design of a component section that must already be provided during the design or manufacture of the monolithically formed hub section.

[0050] If several monolithically formed hub sections have a screw helix base or the (complete) screw helix, the complete centrifuge screw, comprising a screw hub and a screw helix, is formed when the individual hub sections are joined together. When only one screw helix base is formed, the formation of the centrifuge screw is simplified in such a way that, in conjunction with the monolithically formed hub sections, the subsequent application and / or completion of the screw helix can be carried out quickly and cost-effectively within the framework of an automated manufacturing process.

[0051] The screw helix base can have a V-shaped or trapezoidal contour in its cross-section, which is perpendicular to the longitudinal axis of the at least one monolithically formed hub section. The screw helix can be applied to this contour in a subsequent manufacturing process. This has the advantage, for example, in the case of repairs, that the separately applied screw helix blade can be removed in the event of damage, and a new screw helix blade can be attached to the screw helix base.

[0052] Due to the formation of a screw helix foot and / or a complete screw helix as a component section of the monolithically formed hub section, for example, a web-like wall section, in particular a spirally extending web-like wall section, can be designed to be relatively narrow, since due to the monolithic structure, no wide base is required for attaching the screw helix or the screw helix blade.

[0053] In a further third main aspect of the invention, the invention relates to a centrifuge screw comprising a screw hub having at least one longitudinal section with an open wall structure, wherein the longitudinal section has at least two interconnected, monolithically formed hub sections, each monolithically formed hub section having a peripheral wall and two end faces, and a plurality of openings formed in the peripheral wall. According to the invention, at least one monolithically formed hub section has at least one balancing element and / or one balancing section.

[0054] With regard to the centrifuge screw according to the third main aspect of the invention, it should be noted that all features, explanations, and embodiments previously mentioned in connection with the centrifuge screw according to the first and / or second main aspect of the invention can also be applied to a centrifuge screw according to the third main aspect of the invention. This results in similar or identical advantages as those already stated in connection with the centrifuge screw according to the first and / or second main aspect of the invention.

[0055] At least one monolithically formed hub section can have a balancing element and / or a balancing section, in particular if it is designed as a cast body.

[0056] A balancing element is understood to be a thickening of the material that is visible from the outside.

[0057] A balancing section can, for example, also be an increase in the volume of a wall section of the hub section. Alternatively or additionally, it is possible for a balancing section to be designed as a targeted material minimization, such as a wall thickness reduction.

[0058] The balancing element / balancing section is preferably a structural adaptation that is already provided during the design or manufacture of the monolithically formed hub section, since an imbalance in the hub section can already be calculated by calculation or simulation, which can be compensated with the help of the balancing element and / or balancing section.

[0059] In other words, to prevent imbalance, a material shape can be deliberately formed at a previously calculated and / or simulated location on the hub section. Such an embodiment of the invention has the advantage that, after assembly of a worm hub, a design is already improved with regard to any imbalance.

[0060] In a further fourth main aspect of the invention, the invention relates to a centrifuge screw comprising a screw hub which has at least one longitudinal section with an open wall structure, wherein the longitudinal section has at least two interconnected, each monolithically formed hub sections, wherein each monolithically formed hub section has a peripheral wall and two end faces and a plurality of openings are formed in the peripheral wall.

[0061] According to the invention, the monolithically shaped hub sections each have a plurality of webs delimiting the openings of the circumferential walls, wherein at least two webs of a monolithically shaped hub section are connected to one another and form a node point, and wherein a plurality of node points are formed on at least one end face of a monolithically shaped hub section, and the at least two interconnected monolithically shaped hub sections are connected to one another, in particular welded, at least in sections at node points formed on the end faces.

[0062] With regard to the centrifuge screw according to the fourth main aspect of the invention, it should be noted that all features, explanations, and embodiments previously mentioned in connection with the centrifuge screw according to the first and / or second and / or third main aspect of the invention can also be applied to a centrifuge screw according to the fourth main aspect of the invention. Similar or identical advantages arise as those already stated in connection with the centrifuge screw according to the first and / or second and / or third main aspect of the invention.

[0063] Preferably, it is provided that front-side nodes of a first monolithically shaped hub section, which are connected to front-side nodes of a second, adjacent monolithically shaped hub section, form a node of at least four webs.

[0064] A first monolithically formed hub section is connected to at least one second monolithically formed hub section on each end face by means of nodes formed on the end faces.

[0065] The design and arrangement of the nodes on the respective end faces of monolithically formed hub sections to be connected is such that the nodes to be connected each form an enlarged node when the monolithically formed hub sections are connected, whereby these enlarged nodes form a node of at least four webs.

[0066] For example, the nodes are evenly arranged on one end face of a monolithically formed hub section. In particular, in such an embodiment of the invention, the nodes are arranged at equal distances from one another on one end face of the monolithically formed hub section.

[0067] Preferably, especially in this fourth main aspect of the invention, the hub sections are of identical design. In other words, the monolithically shaped hub sections that form an open wall structure of a longitudinal section of the screw hub have the same shape, so that the alignment of the nodes of the monolithically shaped hub sections to be connected can be carried out in a simple and predictable manner.

[0068] Preferably, the first end face of a first monolithically formed hub portion has the same number of nodes as the first end face of a second monolithically formed hub portion.

[0069] Particularly preferably, a monolithically formed hub section has the same number of nodes on both end faces, i.e., on the first end face and on the second end face. This configuration of a monolithically formed hub section serves, in particular, to provide identical parts that can be easily connected to one another.

[0070] In addition, it is possible for a section of a web-like wall section extending spirally with respect to the longitudinal direction of the fully formed hub section to be formed on an end face of a monolithically formed hub section, in addition to at least two nodes. The section of a web-like wall section preferably has a larger area on the at least one end face of the monolithically formed hub section than a single node. Due to the formation of at least one section of a spirally extending web-like wall section on an end face of the monolithically formed hub section, a larger contact surface for monolithically formed hub sections to be connected, in particular for the end faces of the monolithically formed hub sections to be connected, can be enabled in this region.On the one hand, this facilitates the pre-adjustment of the monolithically formed hub sections to each other. Furthermore, the enlarged contact surface in this area allows for the creation of a larger section of a material-to-material connection, particularly a welded joint.

[0071] At least one end face of at least one monolithically formed hub section according to a fourth main aspect of the invention does not have a continuous surface when forming nodes. Rather, the end face is formed from a plurality of end face sections. The end face sections are preferably formed in a common plane that runs perpendicular to the longitudinal axis of the monolithically formed hub section. This allows for the formation of a plurality of monolithically formed hub sections with such end faces, allowing them to be easily aligned with one another.

[0072] Preferably, at least one end face of at least one monolithically formed hub section has at least two, preferably at least three, particularly preferably at least four node points.

[0073] It is possible for at least one web, preferably a plurality of webs, of at least one monolithically formed hub section to be rod-shaped. A web is considered to be rod-shaped if the cross-section of the web is round, at least in sections, and in particular completely.

[0074] A further fifth main aspect of the invention relates to a centrifuge screw, comprising a screw hub having at least one longitudinal section with an open wall structure, wherein the longitudinal section has at least two interconnected hub sections, wherein each hub section has a peripheral wall and two end faces and a plurality of openings is formed in the peripheral wall. At least one hub section of the screw hub is formed from at least two monolithic segments, wherein each monolithic segment forms a radial and / or outer circumferential partial section of the peripheral wall and preferably extends over the entire longitudinal extent of the at least one hub section. With the aid of monolithic segments formed in this way, large hub sections formed from individual monolithic segments, viewed in the radial direction of the hub section, can be produced.

[0075] With regard to the centrifuge screw according to the fifth main aspect of the invention, it should be noted that all features, explanations, and embodiments previously mentioned in connection with the centrifuge screw according to the first and / or second and / or third and / or fourth main aspect of the invention can also be applied to a centrifuge screw according to the fifth main aspect of the invention. Similar or identical advantages arise as those already stated in connection with the centrifuge screw according to the first and / or second and / or third and / or fourth main aspect of the invention.

[0076] A hub section according to the fifth main aspect of the invention is to be understood in particular as an independent component which can be or is connected as an intermediate component to at least one further hub section and / or component.

[0077] Preferably, the monolithic segments forming a hub section are designed such that at least one of the monolithic segments extends over the entire longitudinal extent of the at least one hub section. Particularly preferably, all monolithic segments of the hub section to be formed or already formed extend over the entire longitudinal extent of the at least one hub section.

[0078] In particular, the hub section formed from monolithic segments is not to be understood as being assembled from several annular segments. A radial partial section of the circumferential wall is to be understood as a partial section of the circumferential wall in the radial direction of a hub section. In a further or alternative embodiment of the invention, in particular according to the fifth main aspect of the invention, at least one hub section of the screw hub is formed from at least two monolithic segments, wherein each monolithic segment forms an outer circumferential partial section of the circumferential wall and preferably extends over the entire longitudinal extent of the at least one hub section. In other words, an outer circumferential partial section of the circumferential wall is a partial section of the circumferential wall in the circumferential direction.The circumferential direction is understood to mean, in particular, a direction along the course of the circumferential wall on the outside of the screw hub, clockwise or counterclockwise. The circumferential direction is particularly evident in a cross-section through the screw hub that runs perpendicular to the longitudinal axis of the screw hub.

[0079] In a further or alternative embodiment of the invention, in particular according to the fifth main aspect of the invention, the radial partial section of the circumferential wall is to be referred to as an outer circumferential partial section. In other words, in such an embodiment of the invention, a radial partial section of the circumferential wall is a partial section of the circumferential wall in the circumferential direction. This is also shown by way of example in Figs. 5a and 5b. In such an embodiment of the invention, at least one hub section of the screw hub is formed from at least two monolithic segments, wherein each monolithic segment forms an outer circumferential partial section of the circumferential wall and preferably extends over the entire longitudinal extent of the at least one hub section.

[0080] Preferably, a hub section is formed from only two monolithic segments, wherein both segments extend over the entire longitudinal extent of the at least one hub section and both segments preferably each have abutting surfaces at which the segments abut one another.

[0081] Further preferably, a hub section is formed from three monolithic segments, wherein the three segments extend over the entire longitudinal extent of the at least one hub section, and the segments preferably each have abutting surfaces at which the segments abut one another. The formation of three segments is particularly advantageous when forming a hub section with a large diameter.

[0082] The abutting surfaces preferably have an oppositely inclined profile relative to the longitudinal extent of the hub section. This creates a temporary loose connection between the segments when the segments are joined together. The segments can then be joined laterally at the adjacent abutting surfaces, in particular by applying a weld seam. Depending on the actual size of the hub section to be produced and / or the design of openings in the hub section and / or the area of ​​application of the hub section, it can also be formed from more than two segments.

[0083] A monolithic segment preferably has a plurality of openings that form openings in the peripheral wall of the hub portion. Thus, by manufacturing a segment, a radial and / or outer circumferential section of the peripheral wall with a plurality of openings can be provided.

[0084] If a hub section is made up of only two segments, these segments can also be referred to as half shells, which when joined together form a hub section.

[0085] By joining several segments to form a hub section, it is possible to machine the segments before joining, particularly on the inside—that is, on the side facing the hub section's future longitudinal axis. For example, curvatures can be formed on the inside. Access to the inside of the hub section is significantly easier due to the segment-like design.

[0086] In a preferred embodiment of the invention, at least two hub sections of the screw hub are each formed from at least two monolithic segments, each monolithic segment forming a radial subsection and / or outer circumferential subsection of the circumferential wall of the respective hub section. This radial subsection and / or outer circumferential subsection can preferably extend over the entire longitudinal extent of the respective hub section. In other words, in such an embodiment of the invention, two hub sections, which are preferably connected to one another, are each formed from several monolithic segments.

[0087] Preferably, at least one monolithic segment has rod-shaped peripheral wall sections. In a particularly preferred embodiment of the invention, at least one hub section of the screw hub is formed from at least two monolithic segments, each of which has rod-shaped peripheral wall sections.

[0088] In particular, a web of a peripheral wall which has a, in particular substantially, round cross-section can also be referred to as a rod-shaped peripheral wall section.

[0089] A rod-shaped peripheral wall section can, in particular, have a circular cross-section. With the aid of rod-shaped peripheral wall sections, in particular with the aid of rod-shaped peripheral wall sections with a round cross-section, particularly good separation results are possible with the screw hub having such a monolithic segment. The at least one rod-shaped peripheral wall section can be configured to extend in the longitudinal direction of the screw hub. In such a case, a rod-shaped peripheral wall section runs parallel, in particular substantially parallel, to the longitudinal direction of the screw hub.

[0090] In a further embodiment of the invention, it is possible for at least one rod-shaped peripheral wall section to run at an angle to the longitudinal direction of the fully formed hub section or at an angle to the longitudinal direction of the screw hub. The angle is preferably 1° to 50°, in particular 5° to 45°, in particular 5° to 20°. If at least one rod-shaped peripheral wall section of at least one monolithic segment runs at an angle to the longitudinal direction of the screw hub or at an angle to the longitudinal direction of the hub section, the stability of the segment and of the hub section and consequently of the screw hub is increased. It is possible for several rod-shaped peripheral wall sections to be arranged in alignment with one another. The aligned arrangement with one another occurs when the screw hub is viewed in the longitudinal direction.The rod-shaped peripheral wall sections arranged in alignment with one another can, for example, be interrupted by a curved wall section, in particular by a spirally curved wall section.

[0091] If the monolithic segment has a plurality of rod-shaped peripheral wall sections, a plurality of openings is formed, in particular, between the rod-shaped peripheral wall sections.

[0092] It is also possible for a monolithic segment to have a plurality of rod-shaped peripheral wall sections in the longitudinal direction. In this case, at least two rod-shaped peripheral wall sections may be aligned with one another. The rod-shaped peripheral wall sections, arranged at least in pairs, may be separated from one another by other peripheral wall sections, such as, for example, a spiral-shaped wall section.

[0093] At least one monolithic segment, in particular all monolithic segments, is / are designed as a cast body.

[0094] In other words, at least one of the monolithic segments is manufactured using a casting process. Standard casting materials can be used. A casting process can generally be used to produce extremely complex segment designs. Compared to manufacturing processes that rely on subsequent milling of openings or welding together several bar elements, the production of a segment using a casting process is simpler and more cost-effective.

[0095] When using a casting process, at least one segment is preferably formed from a chromium-nickel steel and / or a duplex steel and / or a nickel-based steel. In a particularly preferred embodiment of the invention, at least one monolithic segment can be produced by a lost-wax casting process.

[0096] Within the framework of a casting process, particularly a lost-wax casting process, it is possible to produce individual sections of at least one segment in different casting quality levels. The casting quality levels to be achieved for individual sections can thus be selected depending on the subsequent component loading and / or acting material stresses.

[0097] Furthermore, it is possible to produce or form individual sections of at least one segment with different wall thicknesses within a casting process, in particular a lost-wax casting process. In other words, individual sections of at least one segment can have different wall thicknesses. The wall thicknesses can be selected depending on the subsequent component loading and / or acting material stresses.

[0098] It is possible to form a multitude of segments using a mold.

[0099] A further sixth main aspect of the invention relates to a centrifuge screw, comprising a screw hub which has at least one longitudinal section with an open wall structure, wherein the longitudinal section has at least two hub sections connected to one another, wherein each hub section has a peripheral wall and two end faces and a plurality of openings are formed in the peripheral wall, wherein the peripheral wall is each formed by a plurality of rods running in the longitudinal direction of the screw hub.

[0100] With regard to the centrifuge screw according to the sixth main aspect of the invention, it should be noted that all features, explanations, and embodiments previously mentioned in connection with the centrifuge screw according to the first and / or second and / or third and / or fourth and / or fifth main aspect of the invention can also be applied to a centrifuge screw according to the sixth main aspect of the invention. Similar or identical advantages arise as those already stated in connection with the centrifuge screw according to the first and / or second and / or third and / or fourth and / or fifth main aspect of the invention.

[0101] This centrifuge screw according to the invention can be designed such that at least one end face of at least one hub section, preferably both end faces of at least one hub section, particularly preferably all end faces of the hub sections, is / are formed by a transverse disc(s). Furthermore, it is possible for at least two adjacent hub sections to be connected to one another at least partially, preferably completely, at the adjacent end faces by means of a material connection, in particular by means of a welded connection.

[0102] This centrifuge screw can be further developed in such a way that at least two hub sections lying against one another are connected to one another at least in sections, preferably completely, at the end faces lying against one another by means of a positive connection and by means of a material connection, in particular by means of a welded connection.

[0103] In addition, it is possible for at least two adjacent hub sections to be connected to one another at least in sections, preferably completely, at the adjacent end faces by means of a positive connection and by means of a material connection, in particular by means of a welded connection.

[0104] Secondly, such a design of a centrifuge screw facilitates the production of the centrifuge screw, in particular the production of the screw hub. In a first step of a joining or manufacturing process, a positive connection of the at least two adjacent hub sections can be made. This is followed by the production of the integral connection, in particular a welded connection, in a second joining step.

[0105] Due to the positive connection, a preliminary adjustment of the adjacent hub sections can be performed. In this pre-adjusted state, the additional material connection, particularly a welded joint, can then be established.

[0106] In one embodiment of the invention, the positive connection is formed by projections formed complementarily to one another on the adjoining end faces of two monolithically formed hub sections.

[0107] The design of a centrifuge screw according to this sixth main aspect of the invention combines several advantages. Firstly, the rod construction of the peripheral wall provides a particularly stable hub section. Furthermore, such a construction is made from common semi-finished products that are easy to obtain.

[0108] In the sixth main aspect of the invention, a hub section of the centrifuge screw according to the invention can consist of at least two cross discs and several rods. The rods can be secured using the cross discs. Such a cross disc can be either a closed cross disc or a cross disc with a central opening. This opening can serve as a flow opening and / or as an opening for the passage of an inlet pipe.

[0109] In a further embodiment of the invention, it is possible for at least one end face of a hub section, preferably both end faces, to be formed by a ring. This ring serves both to fix the rods in place and as a connection point for connecting another, adjacent hub section. The ring can, for example, have several recesses on the outside, with the rods arranged in the recess.

[0110] In a further embodiment of the invention according to the sixth main aspect of the invention, the at least two hub sections are each monolithically formed hub sections. In this case, both the end faces and the rods are, in other words, part of a monolithic basic structure of the hub section. A monolithic design of the hub section has a particularly robust construction, even when formed with rods running in the longitudinal direction of the screw hub. Furthermore, a particularly good separation effect can be achieved with such rods running in the longitudinal direction of the screw hub.

[0111] According to a first embodiment of the invention, rods running in the longitudinal direction of the screw hub are to be understood as a rod positioned in such a way that it runs exactly in the longitudinal direction of the screw hub or parallel to the longitudinal axis of the screw hub.

[0112] In a further embodiment of the invention, it is possible for such a rod which runs at an angle to the longitudinal direction of the screw hub to be referred to as a rod running in the longitudinal direction of the screw hub, provided that the angle to the longitudinal direction of the screw hub is less than 45°, in particular less than 30°, in particular less than 25°. In such an embodiment of the invention, the rod does not run exactly in the longitudinal direction of the screw hub or parallel to the longitudinal axis of the screw hub, but predominantly in the longitudinal direction of the screw hub or in the longitudinal axis direction of the screw hub. A rod which runs at an angle, in particular at one of the above-mentioned angles, to the longitudinal direction of the screw hub or to the longitudinal axis of the screw hub, ensures that a hub section formed in this way can withstand particularly high loads.If the rods run exactly in the longitudinal direction of the screw hub or exactly parallel to the longitudinal axis of the screw hub, they are easier to manufacture.

[0113] A further seventh main aspect of the invention relates to a centrifuge screw comprising a screw hub formed from a plurality of differently shaped hub sections. In other words, the screw hub comprises at least one first hub section and a second hub section, wherein a transition piece, in particular a conical one, is formed between the at least two hub sections. The transition piece establishes a connection between a first hub section with a first outer diameter and a second hub section with a second outer diameter, wherein the outer diameters are different.

[0114] With regard to the centrifuge screw according to the seventh main aspect of the invention, it should be noted that all features, explanations, and embodiments previously mentioned in connection with the centrifuge screw according to the first and / or second and / or third and / or fourth and / or fifth and / or sixth main aspect of the invention can also be applied to a centrifuge screw according to the sixth and / or seventh main aspect of the invention. Similar or identical advantages arise as those already stated in connection with the centrifuge screw according to the first and / or second and / or third and / or fourth and / or fifth and / or sixth main aspect of the invention.

[0115] The transition piece enables in particular a modular construction of a worm hub, whereby several differently designed hub sections can be connected to one another.

[0116] The differently shaped hub sections may differ from one another in terms of their size and / or shape and / or manufacturing method. The differently shaped hub sections may be monolithically formed hub sections and / or hub sections formed from multiple monolithic segments and / or hub sections with longitudinally extending rods and / or hub sections manufactured in a different way.

[0117] Each hub section which is / is connected to another hub section by means of the transition piece can be designed like a monolithically shaped hub section according to the first and / or second and / or third and / or fourth main aspect of the invention.

[0118] Furthermore, it is possible for a hub section, which is connected to at least one further hub section of the screw hub by means of the transition piece, to be a single hub section, as described in connection with the fifth main aspect of the invention. At least one hub section can therefore be formed from at least two monolithic segments, wherein each monolithic segment forms a radial and / or outer circumferential subsection of the circumferential wall, and preferably at least one monolithic segment extends over the entire longitudinal extent of the at least one hub section.

[0119] Furthermore, it is possible for the centrifuge screw according to the invention to have a screw hub, wherein at least one hub section, which is connected to another hub section by means of the transition piece, is a single hub section, as described in connection with the sixth main aspect of the invention. In other words, at least one hub section can have two end faces and a plurality of rods extending in the longitudinal direction of the screw hub, forming the peripheral wall.

[0120] At least one hub section can also be further components and / or sections and / or pieces forming the screw hub. For example, it is possible for a hub section to be designed as a tubular body longitudinal section. Such a tubular body longitudinal section can, for example, be a further cylindrical longitudinal section of the screw hub. It is also possible for the tubular body longitudinal section to form the solids discharge side section of the screw hub. Furthermore, the tubular body longitudinal section can be an end section of the screw hub. The end section can, for example, be the bearing section of a screw hub. Furthermore, it is possible for a hub section, in particular the solids discharge side hub section, to be designed as a double cone.

[0121] With the aid of the transition piece designed according to the invention, hub sections of different designs can be connected to one another, wherein the hub sections can be primarily the wall structure of hub sections forming a screw hub and / or further hub sections with other functions (for example, solids discharge side section or end section or bearing section).

[0122] This simplifies the production of the centrifuge screw in the sense of a modular principle.

[0123] In a particularly preferred embodiment of the invention, the transition piece is conically shaped, allowing for a flow-optimized connection between different sections of the screw hub having different outer diameters. The conical shape makes it possible to create a smooth transition in terms of rigidity between two hub sections, in particular between a hub section of the open wall structure and a longitudinal section of the tubular body. A further advantage is that a preferably performed welding process can be automated, eliminating the need for any interruption or discontinuation during the application of a screw helical weld seam.

[0124] Particularly preferably, the transition piece is designed as a cast body.

[0125] The transition piece can have several openings that preferably allow axial flow. In other words, the transition piece can have several axial flow openings. Axial flow refers to the flow of a medium starting from the interior of the open wall structure in the direction of the longitudinal axis of the screw hub, preferably in the direction of the liquid discharge.

[0126] The transition piece can, in particular if it is designed as a cast body, have at least one balancing element and / or one balancing section.

[0127] A balancing element is understood to be a thickening of the material that is visible from the outside.

[0128] A balancing section can, for example, also be an increase in volume of a wall section of the transition piece. Alternatively or additionally, it is possible for a balancing section to be designed as a targeted material minimization, such as a wall thickness reduction.

[0129] The balancing element / balancing section is preferably a structural adaptation that is already provided during the design or manufacture of the transition piece, since an imbalance in the transition piece can already be calculated by calculation or simulation, which can be compensated for using the balancing element and / or balancing section. In other words, to avoid an imbalance, a material formation can be deliberately formed at a previously calculated and / or simulated point on the transition piece. A further eighth main aspect of the invention relates to a centrifuge screw, comprising a screw hub that has at least one longitudinal section with an open wall structure, wherein the peripheral wall of the screw hub has a polygonal shape, in particular a regular polygonal shape, at least in sections in a cross-section perpendicular to the longitudinal axis of the centrifuge screw.

[0130] With regard to the centrifuge screw according to the eighth main aspect of the invention, it should be noted that all features, explanations, and embodiments previously mentioned in connection with the centrifuge screw according to the first and / or second and / or third and / or fourth and / or fifth and / or sixth and / or seventh main aspect of the invention can also be applied to a centrifuge screw according to the eighth main aspect of the invention. This results in similar or identical advantages as those already stated in connection with the centrifuge screw according to the first and / or second and / or third and / or fourth and / or fifth and / or sixth and / or seventh main aspect of the invention.

[0131] In other words, the centrifuge screw according to the eighth main aspect of the invention is characterized in that the cross-section perpendicular to the longitudinal axis of the centrifuge screw is not circular, at least in sections of the at least one longitudinal section. Rather, the cross-section is polygonal.

[0132] Such an embodiment of the invention provides several advantages. Due to the polygonal shape of the screw hub, the axial flow within a drum with a centrifuge screw according to the invention can be improved. With a polygonal shape of the screw hub, the screw hub can be designed, in particular constructed, such that the high point on the inside of the screw hub is at the same diameter as the low point on the outside of the screw hub. This enables axial flow across the entire diameter range or cross-sectional area.

[0133] In addition, the advanced cross-sectional shape offers manufacturing advantages. Firstly, a flat support surface, which can be achieved due to the polygonal or polygonal shape of the worm hub, is advantageous for clamping the component.

[0134] Secondly, any welded joints that may be formed between individual segments run in a single plane rather than in three-dimensional space. Such welded joints are easier to produce.

[0135] A polygon shape is preferably a pentagon, hexagon, heptagon, or octagon. It has been shown that the above-described advantage is achieved to a particularly high degree in connection with such polygons, especially with such regularly formed polygon shapes.

[0136] In the present invention, a polygon is also understood to mean cross-sectional shapes whose corners are rounded.

[0137] Between the corners, in particular the rounded corners, several side surfaces of the circumferential wall of the worm hub are formed. These side surfaces can be flat. In other words, these side surfaces can be substantially non-curved. A flat side surface is understood to mean, in particular, a side surface that deviates from a completely flat design only due to manufacturing inaccuracies.

[0138] It is possible for the longitudinal section of the screw hub to be monolithically formed. In this case, it may be possible for the entire longitudinal section of the screw hub to be formed as a monolithically formed hub section. In such an embodiment of the invention, the longitudinal section of the screw hub can be manufactured in a single work step, in particular by means of a casting process. In other words, the longitudinal section of the screw hub can be a cast body.

[0139] In a further embodiment of the invention, the longitudinal section can have at least two interconnected, each monolithically formed hub sections. In a further embodiment of the eighth main aspect of the invention, it is possible for the longitudinal section to be designed as such a hub section of the screw hub, which is formed from at least two monolithic segments, wherein each monolithic segment forms an outer circumferential partial section of the circumferential wall and preferably extends over the entire longitudinal extent of the at least one hub section.

[0140] A longitudinal section, in particular a hub section, according to the eighth main aspect of the invention, is to be understood in particular as an independent component which can be or is preferably connected as an intermediate component to at least one further hub section and / or component.

[0141] Particularly preferably, all monolithic segments of the hub section to be formed or formed extend over the entire longitudinal extent of the at least one hub section.

[0142] An outer circumferential partial section of the circumferential wall is to be understood as a partial section of the circumferential wall of a hub section which at least partially forms the outer circumference of a hub section in the circumferential direction.

[0143] Preferably, a longitudinal section, in particular a hub section, is formed from at least three monolithic segments, wherein the segments extend over the entire longitudinal extent of the at least one longitudinal section, in particular the hub section, and the segments preferably each have abutting surfaces at which the segments abut one another. The formation of three segments is particularly advantageous when forming a hub section with a large outer circumference.

[0144] The abutting surfaces preferably have an oppositely inclined profile relative to the longitudinal extension of the longitudinal section, in particular the hub section. This creates a temporary loose connection between the segments when the segments are joined together. The segments can then be joined laterally at the adjacent abutting surfaces, in particular by applying a weld seam.

[0145] At least one monolithic segment, in particular all monolithic segments, is / are formed as a cast body. In other words, at least one of the monolithic segments is manufactured using a casting process.

[0146] Standard cast materials can be used for this purpose. A casting process can generally produce extremely complex structures with a single segment. Compared to manufacturing processes that rely on subsequent milling of openings or welding together several bar elements, the production of a segment using a casting process is simpler and more cost-effective.

[0147] When using a casting process, at least one segment is preferably formed from a chromium-nickel steel and / or a duplex steel and / or a nickel-based steel.

[0148] In a particularly preferred embodiment of the invention, at least one monolithic segment can be produced by a lost wax casting process.

[0149] Within the framework of a casting process, particularly a lost-wax casting process, it is possible to produce individual sections of at least one segment in different casting quality levels. The casting quality levels to be achieved for individual sections can thus be selected depending on the subsequent component loading and / or acting material stresses.

[0150] Furthermore, it is possible to produce or form individual sections of at least one segment with different wall thicknesses within a casting process, in particular a lost-wax casting process. In other words, individual sections of at least one segment can have different wall thicknesses. The wall thicknesses can be selected depending on the subsequent component loading and / or acting material stresses.

[0151] In addition, it should be noted that all of the aforementioned main aspects, namely the first main aspect, the second main aspect, the third main aspect, the fourth main aspect, the fifth main aspect, the sixth main aspect, the seventh main aspect, and the eighth main aspect, are each to be understood as subordinate main aspects that do not necessarily have to have the inventive features of the other main aspects. However, it is not excluded that the aforementioned main aspects, namely the first main aspect, the second main aspect, the third main aspect, the fourth main aspect, the fifth main aspect, the sixth main aspect, the seventh main aspect, and the eighth main aspect, may be combined individually or multiple times.

[0152] The following embodiments and explanations regarding a centrifuge screw according to the invention can be related to all of the main aspects mentioned above, namely main aspects one and / or two and / or three and / or four and / or five and / or six and / or seven and / or eight.

[0153] The end face of an optionally monolithically formed hub section is one of the two end faces of the hub section that close off the circumferential wall in the longitudinal direction of the hub section.

[0154] A monolithically formed hub section is understood to mean, in particular, a hub section that is formed in one piece and without joints.

[0155] A hub section, optionally monolithically formed, is to be understood in particular as an independent component which can be connected as an intermediate component to at least one further hub section and / or component.

[0156] The centrifuge screw according to the invention extends along a longitudinal axis. This longitudinal axis also forms the longitudinal axis of the rotor component of a solid-bowl screw centrifuge. The longitudinal direction of a centrifuge screw is essentially defined by the orientation of the centrifuge screw's longitudinal axis. The longitudinal axis of a centrifuge screw is the axis around which the centrifuge screw rotates during use.

[0157] The longitudinal direction is preferably defined as the direction of transport of the solid discharge.

[0158] In the longitudinal direction of a centrifuge screw according to the invention, it can have at least two different sections. A first section is the cylindrical longitudinal section. A further section following in the longitudinal direction is a solids discharge section. This solids discharge section can, for example, be conical or double-conical, or tubular with a smaller diameter than the cylindrical longitudinal section. A further section of a centrifuge screw can, for example, be a bearing section of the centrifuge screw.

[0159] The medium to be processed or separated using a centrifuge screw according to the invention can be a multiphase medium. The medium can be, for example, a two-phase mixture or a three-phase mixture. It is also possible to use the centrifuge screw according to the invention to separate a three-phase mixture, in which one solid phase and two liquid phases are present.

[0160] The longitudinal section of the screw hub of the centrifuge screw according to the invention with an open wall structure can be formed from a plurality of hub sections, i.e., from at least two interconnected hub sections. The screw hub is formed by at least two, optionally monolithically formed, hub sections, wherein both hub sections have a peripheral wall and at least two end faces, and a plurality of openings are formed in the peripheral wall.

[0161] It is possible for the at least two, optionally monolithically formed, hub sections to be designed differently in terms of their specific configuration. This means that the at least two, optionally monolithically formed, hub sections can differ from one another, for example, in terms of their openings (e.g., arrangement, number, shape). This enables the creation of a customized centrifuge screw that can be specifically adapted to the product to be processed.

[0162] It is also possible for a worm hub to be assembled or manufactured from several similarly formed hub sections. For this purpose, the similar, optionally monolithically formed, hub sections are connected to one another. This allows the production of a large number of similar, optionally monolithically formed, hub sections.

[0163] In a particularly preferred embodiment of the invention, the plurality of openings in the peripheral wall are formed as part of the monolithic shape of the hub sections. This means that the openings are not subsequently introduced into a peripheral wall, but rather the monolithic shape of the hub sections already includes these openings. In other words, the individual monolithically formed hub section is designed such that, due to the manufacturing process, the monolithically formed hub section already has its basic shape. Thus, no further post-processing steps forming the basic shape, such as milling operations for creating openings, are necessary.However, this does not rule out the possibility of the monolithically formed hub section being polished and / or shortened and / or subsequently machined to include fastening elements and / or fastening sections, for example; however, the basic shape of the monolithically formed hub section / the monolithically formed hub sections is already present. The provision of possible projections, such as those required to form a connection point or to prepare a weld seam, cannot be ruled out either. The openings in the respective circumferential wall can have different shapes or geometries. For example, it is possible for the openings to be essentially triangular and / or quadrangular. In particular, it is possible for the openings in a hub section to vary in both size and shape, i.e. to be designed differently.This enables the formation of a peripheral wall with an optimal distribution of openings, particularly with regard to providing a web-like, particularly spiral-shaped, wall section that serves to secure a screw flight. The openings of the respective peripheral wall can be delimited by strut-like and / or web-like elements. In other words, the geometry or shape of the openings can be formed using strut-like and / or web-like elements. The strut-like and / or web-like elements can have a round cross-section.

[0164] At least in sections, the web-like elements can be a / the web-like wall section or a partial section of the web-like wall section that serves to secure a screw flight. Preferably, each opening is formed from at least one partial section of a web-like wall section and at least two struts, wherein the struts are preferably defined as wall sections that serve only to delimit the opening and do not form or have an additional wall section for securing a screw flight.

[0165] Furthermore, it is possible for an opening to be formed from two sections of one or more web-like wall sections and at least two struts.

[0166] In a preferred embodiment of the invention, the openings are triangular in shape, with two triangular openings being arranged relative to each other such that the two openings form a diamond shape. In a particularly preferred embodiment of the invention, the hub section has a plurality of triangular-shaped openings, with two such openings together forming a diamond shape. The diamonds are, in turn, arranged offset from each other in the hub section.

[0167] In a particularly preferred embodiment of the invention, a web-like wall section (which serves to attach a screw flight) runs through the nodes of the struts. This type of hub section design enables a particularly stable yet lightweight construction of the optionally monolithic hub section.

[0168] The length of the respective, optionally monolithically formed, hub section is preferably 0.5 to 3 times, in particular 1 to 2.5 times, in particular 1 to 2 times, the diameter of the hub section. Such length / diameter ratios can provide a monolithically formed hub section, which allows a screw hub of the centrifuge screw to be formed from several, preferably similar or identical, hub sections.

[0169] It is possible that the end faces of at least one, optionally monolithically formed, hub section do not necessarily have to be formed in a plane that is perpendicular to the longitudinal axis of the hub section. Rather, it is possible for at least one end face, preferably both end faces, to be formed obliquely or spirally or to overlap with an adjacently arranged hub section. In such an embodiment of the invention, two, optionally monolithically formed, hub sections to be connected can also be connected to one another by means of an optionally additional, materially bonded connecting section, for example a weld seam, which does not correspond to a circumferential seam.

[0170] The shape of such a hub section with, for example, beveled ends corresponds to the shape of a beveled circular cylinder. The bevel can be formed on both ends or front sides of the hub section. Formation on just one side is also possible, provided, for example, the relevant hub section is designed or positioned as the end section of a cylindrical longitudinal section of the worm hub.

[0171] Preferably, at least one of the monolithically formed hub sections, particularly preferably all monolithically formed hub sections, is designed as a cast body.

[0172] In other words, at least one of the monolithically formed hub sections is manufactured by a casting process.

[0173] Standard cast materials can be used for this purpose. A casting process can generally produce extremely complex designs for a hub section. Compared to manufacturing processes that rely on subsequent milling of openings or welding together several bar elements or components, the production of a hub section using a casting process is simpler and more cost-effective.

[0174] When using a casting process, at least one hub section is preferably formed from a chromium-nickel steel and / or a duplex steel and / or a nickel-based steel.

[0175] In a particularly preferred embodiment of the invention, at least one monolithically shaped hub section can be produced by a lost wax casting process.

[0176] Within the framework of a casting process, particularly a lost-wax casting process, it is possible to produce individual sections of at least one monolithically formed hub section in different casting quality levels. Thus, the casting quality levels to be achieved for individual sections can be selected depending on the subsequent component loading and / or acting material stresses.

[0177] Furthermore, it is possible to produce or form individual sections of at least one monolithically formed hub section with different wall thicknesses using a casting process, in particular a lost-wax casting process. In other words, individual sections of at least one monolithically formed hub section can have different wall thicknesses. The wall thicknesses can be selected depending on the subsequent component loading and / or acting material stresses.

[0178] It is possible to form a variety of hub sections using a mold.

[0179] In the context of the present application, a monolithically formed hub section is preferably not understood to mean a hub section that essentially consists of a tube into which a plurality of openings are subsequently introduced into the peripheral wall. Rather, the term "monolithic forming" refers to a hub section such that, due to an appropriately selected manufacturing process, the shape of the hub section, including the formation of the openings, is formed in a single manufacturing process or manufacturing step.

[0180] In a particularly preferred embodiment of the invention, at least one of the optionally monolithically formed hub sections does not have a cross disk. Particularly preferably, all of the optionally monolithically formed hub sections do not have a cross disk.

[0181] A transverse pane can be either a closed transverse pane or a transverse pane with at least one opening.

[0182] In other words, at least one of the optionally monolithically formed hub sections can be designed without a cross disk. Due to the, in particular optionally monolithic, design of the at least one hub section, it has been shown that the formation of a cross disk is not necessary.

[0183] A centrifuge screw having a screw hub with at least one monolithically formed hub section can be designed so stably, due to the design according to the invention, in particular due to the positive and material-locking connection according to the invention, that the formation of a cross disk is unnecessary. This has the advantage, on the one hand, that a more cost-effective production of the screw hub and thus of the centrifuge screw is possible. Furthermore, such a centrifuge screw has a flow-optimized shape inside the screw hub, at least in sections, since no cross disk influencing the flow is formed. This applies in particular in the case where all hub sections, optionally monolithically formed, do not have a cross disk. Due to the connection according to the invention, sufficient stability of the screw hub and thus of the centrifuge screw is provided.

[0184] It is possible that only one or only individual, but preferably not all, hub sections have a transverse disc.

[0185] In one possible embodiment of the invention, at least one cross disc is formed on one end face of a hub section. Forming a cross disc on only one end face of a hub section has the advantage that material can be saved with regard to the formation of cross discs. By connecting multiple hub sections, a cross disc can be formed between each of the two hub sections to be connected.

[0186] In a further embodiment of the invention, it is possible for a transverse disk to be formed on each of the two end faces of a hub section. This, in turn, has the advantage that the hub sections formed in this way can be formed at any position of the screw hub to be formed. This means that the hub section formed in this way, in particular monolithically, can also form the end part of a cylindrical longitudinal section of a screw hub. This applies both to a discharge-side end part of a cylindrical longitudinal section of a screw hub and to an inlet-side end part of a cylindrical longitudinal section of a screw hub.

[0187] When forming a hub section with two cross discs, it is possible to form the respective cross discs with a relatively thin material thickness. In particular, when connecting two monolithically formed hub sections, a common cross disc with a correspondingly greater material thickness can be formed due to the preferential abutment of at least two cross discs.

[0188] In a further embodiment of the invention, the at least one transverse disk of at least one, optionally monolithically formed, hub section can be formed in the longitudinal direction of the hub section at a position that essentially corresponds to the bisector of the length of the hub section. A position that essentially corresponds to the bisector of the length of the hub section is to be understood in particular as a position that is formed centrally with respect to the length of the hub section. For manufacturing reasons alone, this does not have to correspond 100% exactly to the bisector of the length. Minor deviations, in particular deviations of ± 10%, in particular of ± 5%, are possible here.

[0189] It is possible for a worm hub to be formed from a plurality of hub sections that are differently designed with regard to a possible cross-disk arrangement. For example, it is conceivable for the hub sections positioned centrally with regard to the cylindrical longitudinal section of a worm hub to each be formed with two cross-disks, each formed on an end face of each individual hub section. Hub sections arranged at the ends, on the other hand, can be formed with just one cross-disk, for example. In this case, it is possible for the cross-disk to be formed only on one end face of the hub cutout or, for example, to be formed at a position that essentially corresponds to the bisector of the length of the hub section.

[0190] At least one cross-disk can preferably be annular. Forming a ring shape allows, for example, an inlet pipe of a solid-bowl screw centrifuge to pass through such a cross-disk. Furthermore, a ring shape can allow liquid to flow through a central opening in the cross-disk. For example, the annular cross-disk has a circular width that corresponds at most to half the radius of the outer circle of the cross-disk.

[0191] In a further embodiment of the invention, it is possible for a cross-disk to have at least one opening formed in the center of the cross-disk. This opening can be circular, for example. Furthermore, it is possible for the opening to be elliptical, flower-shaped, or petal-shaped. Preferably, the opening of the cross-disk is shaped such that an inlet pipe of a solid-bowl screw centrifuge can be passed through the opening.

[0192] In a further embodiment of the invention, it is possible for a cross disk of at least one, optionally monolithically formed, hub section to have a plurality of openings arranged around its outer circumference. In this case, the openings are designed such that the preferably circular outer peripheral edge is pierced by a plurality of openings. The openings are preferably evenly distributed in the circumferential direction of the cross disk. This allows, for example, the passage of liquid. The introduction of additional struts or reinforcing rods is also conceivable in this case. In a further embodiment of the invention, at least one cross disk of an optionally monolithically formed, hub section can have a plurality of openings arranged distributed in the circumferential direction. The openings are preferably evenly distributed in the circumferential direction of the cross disk.In other words, the annular shape of a cross disc can, for example, have several evenly distributed openings. Such openings allow the passage of fluids. The circumferentially distributed openings can, for example, be circular, square, or triangular. The actual shape of the openings can be selected depending on the desired flow rate. It is possible for a cross disc of a hub section to have several of the aforementioned features and / or designs.

[0193] Due to a specially selected manufacturing process, the cross plate can have a variable thickness in its monolithic structure. It is therefore possible to form individual sections of the cross plate with a higher material thickness or greater thickness, so that the cross plate forms reinforcing sections at these points. In particular, such points with a higher thickness of the cross plate can be designed as a type of reinforcing strut. The thickness of the cross plate can, for example, decrease from radially outside to radially inside. Furthermore, it is possible for the sections of the cross plate which have a greater thickness or material thickness than the remaining sections of the cross plate to be arranged radially outwards from an (imaginary) center point of the cross plate.

[0194] In a possible embodiment of the centrifuge screw according to the invention, the screw hub can have at least in sections a tubular body longitudinal section, wherein a transition piece, in particular a conically shaped one, is formed between the at least one tubular body longitudinal section and the open wall structure, wherein the transition piece establishes a connection between a tubular body longitudinal section with a first outer diameter and the open wall structure with a second outer diameter, wherein the first outer diameter is preferably smaller than the second outer diameter.

[0195] The tubular body longitudinal section can, for example, be another cylindrical longitudinal section of the screw hub of the centrifuge screw. It is also possible for the tubular body longitudinal section to be the solids discharge section of the screw hub. Furthermore, the tubular body longitudinal section can be an end section of the screw hub. The end section can, for example, be the bearing section of a screw hub.

[0196] Configuring a hub section as a tubular body longitudinal section can, among other things, serve to variably adjust the length of the screw hub. This allows the use of similar hub sections, which are designed identically, particularly in terms of their length, and, for example, form the open wall structure of a screw hub. To customize the length of the screw hub, only an adjustment is necessary in the area of ​​the hub section, which is designed as a tubular body longitudinal section.

[0197] The transition piece(s) enables, in particular, a modular construction of a screw hub, so that the screw hub formed from several hub sections, in particular at least partially from several monolithically formed hub sections, can be connected to other components and / or sections and / or pieces forming the screw hub. This simplifies the production of the centrifuge screw in accordance with a modular principle.

[0198] In a particularly preferred embodiment of the invention, the transition piece is conically shaped so that a flow-optimized connection can be established between different sections of the screw hub which have different outer diameters.

[0199] The conical shape makes it possible to create a smooth transition in terms of stiffness between two hub sections, particularly between a hub section of the open wall structure and a longitudinal section of the pipe body. A further advantage is that a preferred welding process can be automated, eliminating the need for a helical weld seam to be interrupted.

[0200] The transition piece is particularly preferably designed as a cast body. The transition piece can have a plurality of openings that preferably permit axial flow. In other words, the transition piece can have a plurality of axial flow openings. Axial flow refers to the flow of a medium originating from the interior of the open wall structure in the direction of the longitudinal axis of the screw hub, preferably in the direction of the liquid discharge.

[0201] The transition piece, especially if it is designed as a cast body, can have at least one balancing element and / or a balancing section. A balancing element is understood to be, in particular, a material thickening visible from the outside.

[0202] A balancing section can, for example, also be an increase in volume of a wall section of the transition piece. Alternatively or additionally, it is possible for a balancing section to be designed as a targeted material minimization, such as a wall thickness reduction.

[0203] The balancing element / balancing section is preferably a structural adjustment that is already provided during the design or manufacture of the transition piece, since an imbalance in the transition piece can already be calculated by calculation or simulation, which can be compensated with the help of the balancing element and / or balancing section.

[0204] In other words, in order to avoid an imbalance, a material formation can be deliberately formed at a previously calculated and / or simulated point of the transition piece.

[0205] Preferably, a spiral-shaped wall section is formed in the circumferential wall of at least one, optionally monolithically formed, hub section, which extends spirally in the circumferential direction and forms at least one 120° rotation, in particular a > 360° rotation, particularly preferably a > 540° rotation or > 810° rotation, over the entire length of the, optionally monolithically formed, hub section.

[0206] With the aid of such a spirally extending wall section, which forms at least a 120° rotation, in particular a > 360° rotation, particularly preferably a > 540° rotation or > 810° rotation, several, optionally monolithically shaped, hub sections can be combined and connected to one another in a simple manner, so that a spirally extending wall section extending over several hub sections can be formed.

[0207] If this spiral wall section serves as a fastening section of a screw helix, this screw helix can preferably wind with a constant pitch around the screw hub formed from several hub sections.

[0208] The openings formed in the circumferential wall of at least one, optionally monolithically formed, hub section can be arranged spirally in the circumferential direction such that, preferably between longitudinally adjacent openings, at least one web-like wall section is formed which runs spirally in the circumferential direction and forms at least one 120° rotation, in particular a > 360° rotation, particularly preferably a > 540° rotation or > 810° rotation, over the entire length of the hub section.

[0209] The at least one web-like wall section, which extends spirally in the circumferential direction, serves in particular as a fastening surface for a screw flight to be attached to the screw hub. Forming a web-like wall section that extends spirally in the circumferential direction has the advantage that the screw flight can be easily connected to the screw hub in an automated process, in particular in an automated welding process.

[0210] Due to the preferred design of such a spiral-shaped wall section, which forms at least a 120° turn, in particular a > 360° turn, particularly preferably a > 540° turn or > 810° turn, several, optionally monolithically shaped, hub sections can be easily combined and connected to one another, so that a screw flight winds preferably with a constant pitch around the screw hub formed from several hub sections. The spiral-shaped arrangement of the openings in the circumferential wall is preferably to be understood such that the openings as a whole form a spiral shape with regard to their arrangement pattern. This is possible, for example, by different opening geometries and / or opening sizes and / or an arrangement of the openings offset from one another in the longitudinal direction and / or circumferential direction of the hub section.

[0211] The spiral arrangement of the openings is preferably designed such that the openings and / or the struts or strut-like elements delimiting the openings are positioned such that when at least two hub sections are connected, the opening or strut structure is also formed continuously.

[0212] Particularly preferably, when connecting several hub sections, both the web-like wall section and the opening or strut structure run continuously or with the same pitch.

[0213] In an alternative embodiment of the invention, it is possible for at least one, optionally monolithically formed, hub section to lack a spiral wall section in the peripheral wall. This facilitates the basic structural design, as there is a greater degree of freedom with regard to the design of the openings in the peripheral wall. This applies to both the shape of the openings and their size and positioning.

[0214] In a further embodiment of the invention, at least one monolithically formed hub section has a plurality of webs defining the openings in the circumferential wall, wherein the webs, in particular the webs and the at least one web-like wall section, each extend in the longitudinal direction and transversely to the longitudinal direction of the screw hub. Such a web arrangement enables a spiral arrangement of the openings in the circumferential direction in a structurally simple manner.

[0215] As an open wall structure, such a

[0216] This refers to a wall structure that has a large number of openings and / or a large overall opening area in the relevant longitudinal section of the screw hub. The opening area is understood to mean, in particular, the sum of all individual opening areas of individual openings in the relevant hub section. In other words, the opening area does not have to be a single, continuous opening area.

[0217] Preferably, the value of the opening area is larger than the value of the closed area. The closed area is understood to be the portion of the wall structure that does not allow material to pass from the inside of the screw hub to the outside (or vice versa). Furthermore, the closed area is preferably understood to be the sum of all individual closed areas in the peripheral wall of the hub section.

[0218] Furthermore and / or additionally, an open wall structure is understood to mean a wall structure of the longitudinal section of the screw hub that has a high proportion of openings in the circumferential direction. Preferably, the proportion of openings in the circumferential direction of the screw hub is at least 30%, more preferably at least 40%, particularly preferably at least 50%, and further particularly preferably at least 60% of the total wall structure in the circumferential direction. Preferably, the proportion of openings is higher than the proportion of closed surfaces.

[0219] Particularly preferably, the described proportion of openings is formed in the circumferential direction over the entire longitudinal extent of the open wall structure. For the purposes of the invention, a longitudinal extent is understood to mean an extension of a component, a section, etc., that runs essentially in the direction, preferably parallel, to the longitudinal axis of the screw hub and / or the centrifuge screw.

[0220] In a particularly preferred embodiment of the invention, the cylindrical longitudinal section of the screw hub is completely formed with an open wall structure according to previous definitions.

[0221] The formation of an open wall structure contributes to the formation of a large pond depth in a solid bowl screw centrifuge. In a preferred embodiment of the invention, at least one, optionally monolithically formed, hub section can have at least one screw helix root and / or one screw helix. In other words, the optionally monolithically formed hub section can already have a screw helix root and / or one screw helix in its optionally monolithic basic structure.

[0222] The worm screw base and / or the worm screw blade is preferably part of the monolithic structure of the hub section. In such a case, the worm screw base and / or the worm screw blade is not applied to the hub section in a separate manufacturing process. If the optionally monolithically formed hub section has only one worm screw base, the additional worm screw blade can be applied in a separate process. For example, the worm screw blade can be welded onto the worm screw base.

[0223] If several, optionally monolithically formed, hub sections have a screw helix root or the (complete) screw helix, the complete centrifuge screw is already formed when the individual hub sections are joined together, or the formation is already simplified in such a way that when only one screw helix root is formed in conjunction with the hub sections, the subsequent application and / or completion of the screw helix can be produced quickly and cost-effectively within the framework of an automated manufacturing process.

[0224] The worm helix base can have a V-shaped or trapezoidal contour in its cross-section, which is perpendicular to the longitudinal axis of the hub section. The worm helix can be applied to this contour in a subsequent manufacturing process. This has the advantage, for example, in the case of repairs, that the separately applied worm helix blade can be removed in the event of damage, and a new worm helix blade can be attached to the worm helix base.

[0225] Due to the formation of a screw helix foot and / or a complete screw helix as a component section of a hub section, for example, a web-like wall section, in particular the previously explained spirally extending web-like wall section, can be designed to be relatively narrow, since due to the monolithic structure, no wide base is required for attaching the screw helix.

[0226] In a further embodiment of the invention, the peripheral wall of at least one, optionally monolithically formed, hub section can be at least partially

[0227] - on the inner side facing the longitudinal axis of the centrifuge screw, in particular in the direction of the longitudinal axis and / or in the circumferential direction, and / or

[0228] - have at least one bulge section on the outside, in particular in the circumferential direction and / or perpendicular to the longitudinal axis to the outside.

[0229] A bulge section is to be understood in particular as a bulge which is present in addition to the basic bulge of the inner side and / or outer side which is present due to the round cross-section of the hub section and which has a different radius of curvature than the basic bulge.

[0230] In other words, the inner side of the peripheral wall is the inner side of the screw hub, which is the side of the screw hub facing the longitudinal axis of the centrifuge screw. An additional curvature or an additional curvature section on the inner side of the peripheral wall, which can be formed in particular in the direction of the longitudinal axis and / or in the circumferential direction of the hub section, but also transversely to the longitudinal axis and / or transversely to the longitudinal axis, has the effect of minimizing deposition areas for sediment in the application. The inner side of the peripheral wall can thus be convex in sections, so that the size of deposition areas is reduced compared to concave inner side sections.

[0231] In particular, at least one additional bulged section is to be understood on the inner side of the peripheral wall in a transition region from the inner side of the peripheral wall to a side surface that at least partially delimits an opening in the peripheral wall. The side surface can preferably be a side surface of a web. Particularly preferably, a bulged section is formed on all transition sections formed to side surfaces of a web.

[0232] Alternatively or additionally, such an additional curvature or an additional curvature section can also be formed on the outer side of the peripheral wall. The curvature can be formed in the circumferential direction of a rotating centrifuge screw and / or perpendicular to the longitudinal axis.

[0233] In particular, at least one additional bulged section is to be understood on the outer side of the peripheral wall in a transition region from the outer side of the peripheral wall to a side surface that at least partially delimits an opening in the peripheral wall. The side surface can preferably be a side surface of a web. Particularly preferably, a bulged section is formed on all transition sections formed to side surfaces of a web.

[0234] Due to the optional formation of bulges on the outer side of the peripheral wall, a pressing / pressing effect on the solid material can be achieved with a rotating centrifuge screw.

[0235] Furthermore, it is possible for the outer side of the peripheral wall to be deliberately designed with sharp edges in the area bordering the openings. In other words, the boundary edges of the openings in the peripheral wall can be designed in such a way that they have a cutting effect during operation of the screw hub.

[0236] Due to the targeted formation of curvatures on the inside and / or outside as well as due to the targeted formation of sharp-edged sections in the peripheral wall, the shape of an optionally monolithically formed hub section can be deliberately selected so that either a cutting and / or a pressing / pressing effect of the centrifuge screw on the solid is achieved.

[0237] At least one hub section, optionally monolithically formed, can have at least one balancing element and / or balancing section, particularly if it is designed as a cast body. A balancing element is understood to be, in particular, a material thickening visible from the outside.

[0238] A balancing section can, for example, also be an increase in the volume of a wall section of the hub section. Alternatively or additionally, it is possible for a balancing section to be designed as a targeted material minimization, such as a wall thickness reduction.

[0239] The balancing element / balancing section is preferably a structural adjustment already provided during the design or manufacture of the optionally monolithically formed hub section, since an imbalance in the hub section can be calculated through calculation or simulation, which can then be compensated for using the balancing element and / or balancing section. In other words, to prevent an imbalance, a material shape can be deliberately formed at a previously calculated and / or simulated location on the hub section. Such an embodiment of the invention has the advantage that, after assembly of a worm hub, a design is already available that is improved with regard to any imbalances.

[0240] It is possible that the hub sections, which are optionally monolithically formed, are made of different materials and / or assembled.

[0241] The targeted application of wear protection materials to individual, optionally monolithically formed, hub sections or individual sections of hub sections is also possible. This type of wear protection can be applied during the production of a monolithically formed hub section.

[0242] Likewise, even within the scope of a monolithic forming process, additional internals can be formed on at least one monolithically formed hub section and / or on at least one monolithic segment of the centrifuge screw according to the invention. Such internals can be bars and / or acceleration bars and / or circulation devices and / or paddles. In yet another embodiment of the invention, it is possible for at least one, optionally monolithically formed, hub section not to have a consistently uniform outer diameter. Rather, it is possible for the outer diameter to vary such that from one end face to the next, there is initially an increase in the outer diameter and then a decrease in the outer diameter. In this case, an optionally monolithically formed hub section with such a curvature, which is bulbous, is formed.Furthermore, it is possible for several, optionally monolithically formed, hub sections to have different outer diameters compared to one another. In particular, it is possible for a hub section formed centrally in relation to the entire longitudinal extension of the screw hub to have a larger outer diameter than at least one adjacent hub section, which is preferably formed at the end of the screw hub. Thus, a correspondingly reinforced screw hub is formed at the most critical bending point of the screw hub or centrifuge screw.

[0243] In a further embodiment of the invention, a bearing support of the centrifuge screw can have the same shape as a / the transition piece. This allows the provision of identical parts, so that a centrifuge screw, in particular a screw hub of the centrifuge screw, can be constructed according to the modular principle.

[0244] The screw hub of a centrifuge screw according to the invention according to one of the preceding main aspects, in particular according to the first and / or second and / or third and / or fourth and / or fifth and / or sixth and / or seventh and / or eighth main aspect, can have several, in particular two or three or four or five, hub sections that are connected to one another. The connected hub sections form a longitudinal section of the screw hub, preferably the entire longitudinal section of the screw hub. Thus, the cylindrical longitudinal section of a screw hub can be formed from several, for example, similar or identical hub sections. This enables simple modular assembly or joining of the screw hub from a selectable number of hub sections. A cylindrical longitudinal section of a screw hub can optionally also be formed from different types of hub sections.The design of the hub sections of the same and different types makes it possible to initially produce a large number of similar hub sections.

[0245] These similar hub sections can be kept in stock and, in the case of an order for the production of a screw centrifuge, can be optionally removed from the warehouse and combined with other types of hub sections, for example. The combination of hub sections depends on the application of the centrifuge screw to be manufactured.

[0246] Multiple hub sections, especially multiple monolithically formed hub sections, can be connected to one another in a material-to-material and / or form-fitting manner. A welded connection is particularly suitable for a material-to-material connection. This enables a stable connection between the hub sections. It is also a comparatively simple method for connecting the hub sections, and the corresponding welding process can also be carried out automatically.

[0247] The hub sections are preferably connected to one another in such a way that web-like wall sections of the hub sections to be connected are positioned relative to one another in such a way that a continuously spiral fastening section for fastening a screw helix is ​​formed over the entire longitudinal section of the screw hub.

[0248] This enables the secure and automated attachment of a screw flight to the screw hub. In a further embodiment of the invention, several web-like wall sections can be formed in the peripheral wall. This allows the formation of several attachment sections for attaching several screw flights.

[0249] It is possible for the fastening sections to already have a screw helix base, so that an additional screw helix section can be easily attached to the screw helix base. With the aid of a centrifuge screw formed according to the invention, it is advantageously possible to replace or repair individual hub sections of screw hubs if they are defective or show signs of wear. This also applies to hub sections of screw hubs that are not or were not initially designed according to the invention, wherein the screw hub comprises a hub section of a screw hub according to the invention after a repair has been carried out.

[0250] It is possible for the centrifuge screw to have multiple screw flights, in particular two screw flights. In this case, at least two spaced-apart web-like wall sections are formed in the peripheral wall of the at least one hub section, preferably of the plurality of hub sections, to enable the two screw flights to be secured.

[0251] It is possible for at least one, optionally monolithically formed, hub section to have rod-shaped peripheral wall sections and / or webs. A rod-shaped peripheral wall section and / or a web can, in particular, have a round cross-section. With the aid of rod-shaped peripheral wall sections, in particular with the aid of rod-shaped peripheral wall sections with a round cross-section and / or webs with a round cross-section, particularly good separation results are possible using a screw hub having such a hub section.

[0252] The at least one rod-shaped peripheral wall section can be configured to extend in the longitudinal direction of the screw hub. In such a case, a rod-shaped peripheral wall section runs parallel, in particular substantially parallel, to the longitudinal direction of the screw hub. The rod-shaped peripheral wall section can be a strut-like or web-like element with a round cross-section.

[0253] In a further embodiment of the invention, it is possible for at least one rod-shaped peripheral wall section to extend at an angle to the longitudinal direction of the completely, in particular monolithically, formed hub section or at an angle to the longitudinal direction of the screw hub. The angle is preferably 1° to 50°, in particular 5° to 45°, in particular 5° to 20°.

[0254] If at least one rod-shaped peripheral wall section of at least one hub section runs at an angle to the longitudinal direction of the screw hub or at an angle to the longitudinal direction of the hub section, the stability of the hub section and consequently of the screw hub is increased.

[0255] It is possible for several rod-shaped circumferential wall sections to be arranged in alignment with one another. The aligned arrangement is apparent when viewing the screw hub in the longitudinal direction. The aligned rod-shaped circumferential wall sections can, for example, be interrupted by a curved wall section, in particular by a spirally curved wall section.

[0256] If the monolithic segment has a plurality of rod-shaped peripheral wall sections, the plurality of openings is formed between the rod-shaped peripheral wall sections.

[0257] It is also possible for a hub section, in particular a monolithically formed one, to have a plurality of rod-shaped peripheral wall sections in the longitudinal direction. In this case, at least two rod-shaped peripheral wall sections may be aligned with one another. The rod-shaped peripheral wall sections, arranged at least in pairs, may each be separated from one another by other peripheral wall sections, such as, for example, a spiral-shaped wall section.

[0258] In a further embodiment of the invention, it is possible for an optionally monolithically shaped hub section to have a peripheral wall which, at least in sections, forms a polygonal shape, in particular a regular polygonal shape, in a cross-section perpendicular to the longitudinal axis of the centrifuge screw.

[0259] In other words, such a hub section is characterized by the fact that the cross-section perpendicular to the longitudinal axis of the centrifuge screw is not circular. Rather, the cross-section is polygonal.

[0260] The polygon shape is preferably a pentagon, hexagon, heptagon, or octagon. In the present invention, a polygon shape also includes cross-sectional shapes with rounded corners.

[0261] Between the corners, in particular the rounded corners, several side surfaces of the circumferential wall of the worm hub are formed. These side surfaces can be flat. In other words, these side surfaces can be substantially non-curved. A flat side surface is understood to mean, in particular, a side surface that deviates from a completely flat design only due to manufacturing inaccuracies.

[0262] Another main aspect of the invention relates to a solid-bowl screw centrifuge comprising a centrifuge screw located in a drum, wherein the centrifuge screw is designed according to the invention. The solid-bowl screw centrifuge according to the invention has a centrifuge screw according to the first and / or second and / or third and / or fourth and / or fifth and / or sixth and / or seventh and / or eighth main aspect of the invention.

[0263] With regard to the solid bowl screw centrifuge, reference is made to the advantages explained in connection with the centrifuge screws according to the invention.

[0264] Another main aspect of the invention relates to a method for producing a centrifuge screw, in particular a centrifuge screw according to the invention.

[0265] The method comprises the steps of: a) providing at least two, optionally monolithically formed, hub sections, wherein each, optionally monolithically formed, hub section has a peripheral wall and two end faces and a plurality of openings are formed in the peripheral wall, b) positively connecting the at least two, optionally monolithically formed, hub sections, c) materially connecting, in particular welding, the at least two, optionally monolithically formed, hub sections.

[0266] According to step a), the method comprises providing at least two hub sections. These can be hub sections formed from monolithic segments and thus form a single hub section. These hub sections, as well as monolithically formed hub sections, each have a peripheral wall and two end faces, with a plurality of openings formed in the peripheral wall.

[0267] The provided hub sections are connected in a form-fitting manner according to step b). This form-fitting connection enables the hub sections to be connected to one another in such a way that sliding apart of such hub sections is prevented, at least in the radial direction. With the aid of this form-fitting connection, step c) can be simplified, namely the materially bonding, in particular welding, of the at least two hub sections.

[0268] Preferably, in step a), the monolithically formed hub sections are produced by means of a casting process.

[0269] The casting process allows the use of standard cast materials, among others. A casting process can generally produce extremely complex designs for a hub section. Compared to manufacturing processes that rely on subsequent milling of openings or welding together several bar elements or components, the production of a hub section using a casting process is simpler and more cost-effective.

[0270] When using a casting process, the at least one monolithically formed hub section is preferably formed from a chromium-nickel steel and / or a duplex steel and / or a nickel-based steel.

[0271] In a particularly preferred embodiment of the invention, the at least one monolithically formed hub section is manufactured using a lost-wax casting process. Within the framework of a casting process, in particular a lost-wax casting process, it is possible to produce individual sections of the at least one monolithically formed hub section in different casting quality levels. Thus, the casting quality levels to be achieved for individual sections can be selected depending on the subsequent component loading and / or acting material stresses.

[0272] Furthermore, it is possible to produce or form individual sections of the at least one monolithically formed hub section with different wall thicknesses using a casting process, in particular a lost-wax casting process. In other words, individual sections of the at least one monolithically formed hub section can have different wall thicknesses. The wall thicknesses can be selected depending on the subsequent component loading and / or acting material stresses.

[0273] In a further embodiment of the invention, the at least one monolithically shaped hub section can be manufactured using a 3D printing process. The 3D printing process described below can also be used to produce a monolithic segment of a hub section.

[0274] Manufacturing using 3D printing also enables the construction of complex shapes or structures within a monolithic hub section. Thanks to the 3D printing process, all sections and sub-areas of the hub section can be manufactured in a single production step, eliminating the need for rework, such as the subsequent creation of openings using a milling process.

[0275] When using a 3D printing process, the at least one hub section is preferably formed from a chromium-nickel steel and / or a duplex steel and / or a nickel-based steel.

[0276] A 3D printing process can, for example, be carried out through a shaping additive material deposition process. The shaping additive material deposition can, for example, be carried out using a shielding gas welding device. The shielding gas welding device is preferably operated with a welding gas selected from one of the subgroups of main groups I, M1, M2, or N of the DIN EN ISO 14175 standard.

[0277] Welding is preferably performed using an active, reactive welding gas or an inert welding gas. This type of welding process can also be referred to as MAG or MIG welding, or as welding with active gas or inert gas. Such welding processes are collectively referred to as gas metal arc welding (GMAW).

[0278] Main Group I includes welding gases with 100 volume percent nominal argon (Subgroup 1), 100 volume percent nominal helium (Subgroup 2), and 0.5 to 95 volume percent nominal helium, with the remainder argon (Subgroup 3). These welding gases are completely inert.

[0279] Main group Ml, subgroup 1 includes welding gases with 0.5 to 5.0 volume percent nominal carbon dioxide, 0.5 to 5.0 volume percent nominal hydrogen and the balance argon or helium. These welding gases are slightly oxidizing and only slightly reducing. Main group Ml, subgroup 2 includes welding gases with 0.5 to 5.0 volume percent nominal carbon dioxide and the balance argon or helium. These welding gases are slightly oxidizing. Main group Ml, subgroup 3 includes welding gases with 0.5 to 3.0 volume percent nominal oxygen and the balance argon or helium. These welding gases are also slightly oxidizing. Main group Ml, subgroup 4 includes welding gases with 0.5 to 5.0 volume percent nominal carbon dioxide, 0.5 to 3.0 volume percent nominal oxygen and the balance argon or helium. These welding gases are also slightly oxidizing.

[0280] Main group M2, subgroup 0 includes welding gases with 5.0 to 15.0 volume percent nominal carbon dioxide and the remainder argon or helium. These welding gases have low oxidizing power. Main group M2, subgroup 1 includes welding gases with 15.0 to 25.0 volume percent nominal carbon dioxide and the remainder argon or helium. These welding gases also have low oxidizing power. Main group M2, subgroup 2 includes welding gases with 3.0 to 10.0 volume percent nominal oxygen and the remainder argon or helium. These welding gases also have low oxidizing power. Main group M2, subgroup 3 includes welding gases with 0.5 to 5.0 volume percent nominal carbon dioxide, 3.0 to 10.0 volume percent nominal oxygen and the remainder argon or helium. The main group M2, subgroup 4 includes welding gases with 5.0 to 15.0 volume percent nominal carbon dioxide, 0.5 to 3.0 volume percent nominal oxygen and the remainder argon or helium.Main group M2, subgroup 5 includes welding gases with 5.0 to 15.0 volume percent nominal carbon dioxide, 3.0 to 10.0 volume percent nominal oxygen, and the balance argon or helium. Main group M2, subgroup 6 includes welding gases with 15.0 to 25.0 volume percent nominal carbon dioxide, 0.5 to 3.0 volume percent nominal oxygen, and the balance argon or helium. Main group M2, subgroup 7 includes welding gases with 15.0 to 25.0 volume percent nominal carbon dioxide, 3.0 to 10.0 volume percent nominal oxygen, and the balance argon or helium. These welding gases are also comparatively low in oxidation.

[0281] Main group N, subgroup 1 includes welding gases with 100 volume percent nominal nitrogen. Main group N, subgroup 2 includes welding gases with 0.5 to 5.0 volume percent nominal nitrogen and the balance argon or helium. Main group N, subgroup 3 includes welding gases with 5.0 to 50.0 volume percent nominal nitrogen and the balance argon or helium. Main group N, subgroup 4 includes welding gases with 0.5 to 1.0 volume percent nominal hydrogen, 0.5 to 5.0 volume percent nominal nitrogen and the balance argon or helium. Main group N, subgroup 5 includes welding gases with 0.5 to 50.0 volume percent nominal hydrogen and the balance nitrogen. All of these welding gases are inert. They are inert with high argon or helium content and they are only slightly reducing even with increasing hydrogen content.

[0282] In summary, welding gases that are inert, have low oxidizing and / or low reducing properties are preferably selected. With such a process, formative build-up welding or formative additive material deposition can be carried out with a low-oxidation weld bead and largely without slag. This is particularly advantageous for superimposing weld beads. In addition, a particularly fast welding speed can be achieved. This initially enables particularly short production times. The actual advantage of a fast welding speed, however, is that the at least one monolithically formed hub section is only heated to a small extent at specific points during welding, thus resulting in little distortion or deformation. A major advantage of the described procedure is that this type of build-up welding results in a particularly high level of wear resistance of the surface produced.

[0283] For example, according to this embodiment, subsequent treatment, in particular the application of wear layers, can be dispensed with.

[0284] For example, the welding gas has a nominal carbon dioxide content of less than 20 percent by volume. Such a low carbon dioxide content makes it possible, in particular, to process structural steels using pulse welding. At the same time, a comparatively high burn-off of the welding wire is possible. This results in high mass build-up during welding and particularly fast processing. Furthermore, welding gas with a nominal oxygen content of less than 3 percent by volume is preferably used as the welding gas. Such welding gases are particularly low in oxidation. Welding gases with a high argon content are also particularly inexpensive.

[0285] In one embodiment of the invention, a gas-shielded welding device is operated with a pulsed arc. Such a pulsed arc allows precise control of the melting of the welding wire on the gas-shielded welding device. Furthermore, the heat input into the at least one monolithically formed hub section can be deliberately kept particularly low. This makes it possible to minimize temperature-related deformations. The electrical welding current of such a pulsed arc welding device has, for example, a base current of less than 200 amperes and a pulsed current of greater than 200 amperes. Such welding currents are advantageous for particularly precise material build-up with comparatively low heat input. The welding gas used is advantageously a welding gas with 98 volume percent nominal argon and 2 volume percent nominal carbon dioxide.

[0286] It is also particularly advantageous to operate a gas-shielded welding system with a short arc, especially a reduced-energy short arc. This type of process with a short arc is also known as a cold arc, a process with a particularly cold arc. To achieve a still highly molten arc, it is particularly advantageous to use an increased melting current pulse.

[0287] A shielding gas welding device is particularly advantageously operated with one welding wire, or advantageously two welding wires (twin welding process) with a diameter of 0.5 mm to 3.0 mm, preferably from 1.0 mm to 1.6 mm.

[0288] Such a welding wire diameter enables high welding speeds and, at the same time, particularly low thermally induced deformation. Individual welding layers or welding passes with a width of 6 to 7 mm are particularly preferred. If a contour is to be produced using the method according to the invention, a welding layer or welding pass has a width of at least 2 mm.

[0289] The at least one hub section or segment to be formed monolithically can preferably be moved during manufacturing. During this movement, the at least one hub section / segment to be formed monolithically is aligned at its welding point in such a way that an optimal position is achieved for the applied welding layer. The welding layer is particularly preferably applied to a horizontal surface.

[0290] It is also advantageous if the weld layer is applied to a surface that slopes slightly in the welding direction. The slope angle is preferably between 5° and 15°, advantageously between 7° and 10°. The at least one hub section / segment to be formed monolithically is preferably moved such that a horizontal welding surface or a welding surface that slopes upwards in the welding direction of the inert gas welding device is present at the welding location of the inert gas welding device.

[0291] The invention is explained in more detail below with reference to the accompanying drawings.

[0292] The illustrated embodiments represent examples of how the centrifuge screw according to the invention can be designed. In particular, the figures depict monolithically shaped hub sections and / or monolithically shaped segments, which, according to particularly preferred embodiments, can form the screw hub of a centrifuge screw.

[0293] The figures show:

[0294] Fig. 1 is a side view of an inventive

[0295] centrifuge screw;

[0296] Fig. 2a and 2b show a first embodiment of a screw hub of a centrifuge screw according to the invention formed from monolithically shaped hub sections in longitudinal section and a side view;

[0297] Fig. 2c to 2f show two further embodiments with regard to a monolithically shaped hub section and associated representation of a worm hub formed from several monolithically shaped hub sections;

[0298] Fig. 3 a monolithically formed hub section with

[0299] snail-footed fungus;

[0300] Fig. 4a and 4b further embodiments with regard to a monolithically formed hub section and associated representation of several such monolithically formed hub sections in connected form for producing a centrifuge screw according to the invention,

[0301] Fig. 5a and 5b show a representation of a monolithic segment for producing a hub section and a corresponding representation of several hub sections formed in this way for producing the screw hub of a centrifuge screw according to the invention;

[0302] Fig. 5c shows a representation of another embodiment of a monolithic segment for producing a hub section; Fig. 6 shows a representation of a transition piece according to the invention;

[0303] Fig. 7 is a representation of a monolithically formed hub section with balancing section; and

[0304] Fig. 8 shows a representation of a hub section with hexagonal

[0305] Circumferential wall cross-section.

[0306] In the following, the same reference numbers are used for identical and equivalent parts.

[0307] Fig. 1 shows a centrifuge screw 100 according to the invention with a screw hub 10. The screw hub 10 has, in the longitudinal direction LR, a cylindrical longitudinal section 11, a solids discharge section 12, and a bearing section 13. Sections 11, 12, and 13 have the longitudinal axis L as a common axis.

[0308] The bearing section 13 serves to accommodate a bearing, in particular a worm bearing, in order to rotatably support the worm hub 10.

[0309] In the present case, the solids discharge section 12 is conical. It is possible for the section 12 to have a shape other than a simple cone in further embodiments of the invention. For example, the section 12 can be designed as a cylindrical section and a cylindrical tube section.

[0310] Furthermore, it is possible for section 12 to have a double truncated cone shape. The cylindrical longitudinal section 11 of the screw hub 10 is arranged in the longitudinal direction LR between the solids discharge section 12 and the bearing section 13. Sections 11, 12, and 13 are firmly connected to one another.

[0311] The worm hub 10 is surrounded radially on the outside by the worm spiral 80.

[0312] The screw hub 10 thus serves to support the screw flight 80 in the radial direction, to transmit torque from the drive to the screw flight 80, and in particular to absorb tensile and thrust forces. The longitudinal direction LR runs essentially parallel to the longitudinal axis L of the screw hub 10. In this case, the longitudinal direction LR is defined as the direction of transport of the solids discharge. The solids transport occurs from right to left as shown in Fig. 1.

[0313] The cylindrical longitudinal section 11 is longer than the solids discharge side section 12. The section 12 of the screw hub 10 is to be understood as such a section which serves in particular for transporting the solids separated from the material to be processed in the direction LR of the solids discharge.

[0314] In the example shown, the cylindrical longitudinal section 11 of the worm hub 10 is formed from five hub sections 20a, 20b, 20c, 20d and 20e.

[0315] The hub sections 20b, 20c, 20d, and 20e are monolithically formed hub sections. The shape of these monolithically formed hub sections 20b-20e essentially corresponds to the illustrations in Figs. 2a and 2b. Hub section 20a, on the other hand, is designed as a longitudinal tubular body section.

[0316] The hub sections 20b-20e form a longitudinal section of the screw hub 10 with an open wall structure. This open wall structure has a large number of openings 22 and a large overall opening area. The opening area is understood to be the sum of all individual opening areas of individual openings 22 in the respective hub sections 20b-20e. In the example shown, the opening area is larger than the closed area.

[0317] The hub sections 20b-20d can be referred to as the middle hub sections. These are located between the end hub sections 20a and 20e. The end hub section 20a forms the end part of the cylindrical longitudinal section 11 facing the solids discharge section 12. The end hub section 20e, on the other hand, forms the end part or end section of the cylindrical longitudinal section 11 facing the bearing section 13 or the end of the screw hub 10 opposite the solids discharge section 12. The hub sections 20b-20e each have a circumferential wall 21 in which a plurality of openings 22 are formed.

[0318] The hub sections 20b, 20c, 20d, and 20e are of identical design according to the embodiment of Fig. 1. This means that these hub sections 20b, 20c, 20d, and 20e are of identical design as monolithically formed hub sections, with openings 22 formed in the respective peripheral wall 21 of the hub sections. In this case, the openings 22 have triangular and quadrangular shapes. The arrangement of the openings 22, as well as the opening shapes and cross-sections, are selected such that a large opening area is provided and, in addition, a spiral-shaped wall section 25 is formed, which serves as the base or fastening base of a screw flight 80. Regarding the exact shape of the hub sections 20b-20e and the connection of these hub sections, reference is made to Figs. 2a and 2b.

[0319] The length LN of the respective hub section 20b-20d is preferably one to two times the diameter D of the hub section. In the present case, the hub sections 20b-20e are of identical design. This also applies to the length LN of the hub sections and the corresponding ratios to the respective diameter D of the hub section.

[0320] A transition piece 50 is formed between the hub sections 20a and 20b, which serves to connect the two hub sections 20a and 20b. The transition piece 50 is designed such that the two hub sections 20a and 20b can be connected to each other despite their different outer diameters. The first outer diameter of the hub section 20a, which forms a longitudinal section of the tubular body, is smaller than the second outer diameter of the monolithically formed hub section 20b.

[0321] In the example shown, the transition piece 50 is designed to be closed, meaning that starting from the interior of the longitudinal section with an open wall structure of the screw hub 10, no flow is possible in the direction of the solids discharge-side section 12. Designing a hub section 20a as a tubular body longitudinal section can serve, among other things, to variably adjust the length of the screw hub 10. This enables the use of similar hub sections 20b-20e, which are designed identically, in particular with regard to their length LN, so that with regard to individualizing the length of the screw hub 10, only an adjustment in the region of the hub section 20a is necessary.

[0322] Fig. 2a shows a longitudinal section through two interconnected hub sections 20b and 20c. Hub sections 20b and 20c each have a first end face 31, 31' and a second end face 32, 32'. The two hub sections 20b and 20c define the longitudinal extent of the peripheral wall 21 of the respective hub section.

[0323] The hub sections 20b and 20c, or in transfer to the centrifuge screw 100 shown in Fig. 1 the hub sections 20b-20e, are connected to one another in such a way that the second end face of a hub section is connected to the first end face of the adjacent or adjacent hub section.

[0324] No further components are present inside or on the inner side 37 of the hub sections 20a-20e connected in this way, as shown in cross-section. It has been shown that the formation of cross disks and the like is not necessary when forming the hub sections shown. The construction is sufficiently stable and resistant to bending.

[0325] The hub sections shown in Fig. 2a (also applies to Fig. 1 and Fig. 2b) are connected to each other in a form-fitting and material-fitting manner.

[0326] To create the positive connection, projections of complementary design are formed on the adjacent end faces 32 of the hub section 20b and 31' of the hub section 20c. Since the hub sections 20b and 20c are of identical design in the present case, projections of the first type are formed on the first end face 31, 31', and projections of the second type 34 are formed on the second end faces 32, 32'.

[0327] The projection of the first type 33 is a nose shape that projects beyond the remaining part of the first end face 31, which is ring-shaped here. The projection of the second type 34 is a step-like shape. Both the projection of the first type 33 and the projection of the second type 34 have inclined surfaces 35 or merge into inclined surfaces 35, so that when the two projections of the first and second type 33 and 34 abut one another, a groove 36 is formed. In Fig. 2a, the abutting end faces 32 and 31' show that the projection of the first type 33 rests on the projection of the second type 34. A positive connection is formed.

[0328] In a further process step, the material connection between the two hub sections 20b and 20c is established. For this purpose, the connecting means is introduced into the groove 36. Particularly preferably, a weld seam section 38, preferably a weld seam, is formed in the groove 36. The weld seam is annular due to the illustrated end faces 32 and 31', which run perpendicular to the longitudinal axis L.

[0329] Regarding the formation of weld seams 38, reference is made to the illustration in Fig. 2b. The weld seams can be applied in such a way that a flush transition from the hub sections 20b-20e to one another is possible. For example, the weld seam 38 can also be reground. The weld seam 38 preferably does not protrude beyond the outer sides 39 of the connected hub sections 20b-20c.

[0330] In particular, Fig. 2b also shows that the openings 22 in the circumferential walls 21 are predominantly formed by webs 40. Furthermore, the spiral wall section 25 can be seen. The individual hub sections 20b-20d (in the case of Fig. 1: 20b-20e) are positioned relative to one another such that the spiral wall sections 25 form a web-like wall section that runs continuously with respect to the longitudinal section of the screw hub 10 with an open wall structure. This continuous web-like wall section preferably has a constant pitch over the entire length of the cylindrical longitudinal section 11.

[0331] In the case of hub sections 20b-20d (or 20e according to Fig. 1), the respective spiral wall section 25 extends over the entire length LN of the hub section in such a way that a rotation of more than 360°, specifically a rotation of 540°, is formed. By offsetting the hub sections from one another by 180°, a spiral wall section can be formed that extends over the entire longitudinal section with an open wall structure.

[0332] Fig. 2c and 2d show a further possibility regarding the formation of hub sections 20, which are connected to each other both in a form-fitting manner and in a material-fitting manner.

[0333] Fig. 2c shows a single hub section 20. The peripheral wall 21 features a plurality of webs 40 that define openings 22. The openings 22 are triangular in shape, with the triangular openings extending spirally offset from one another (see Fig. 2b).

[0334] A spiral wall section 25 can serve to define two adjacent triangular openings. For all openings 22 of the hub section 20 shown in Fig. 2, these are each formed by two webs 40 and a partial section of the spiral wall section 25. Additionally, openings 22 can be positioned relative to one another such that they together form a diamond shape. Several diamonds are, in turn, arranged offset from one another in the hub section 20.

[0335] In the embodiment according to Figs. 2c and 2d, the positive connection is formed by projections 41, which in turn are formed by the shape of the open wall structure itself. Specifically, the projections 41 are designed as serrated projections, which are present as webs 40 bounding the openings 22. The projections 41 can also be referred to as serrated sections of the hub section. Specifically, the projections 41 on the first end face are offset from the projections 41 on the second end face 32. If several hub sections 20 formed in this way are positioned adjacent to one another, a projection 41 of a first end face lies in a free space 42 formed between two projections 41 on the second end face.

[0336] In the case of the hub section shown in Fig. 2c, the two end faces 31 and 32 are formed by a plurality of end face sections 44. The end face sections are connected to one another by rounded sections 45. As shown in the illustration according to Fig. 2d, the end face sections 44 are arranged obliquely in the direction of the longitudinal axis L.

[0337] In the embodiment according to Figs. 2c and 2d, the end face sections 44 are formed by side surfaces of webs 40 that define openings 22 in the peripheral wall 21. In other words, the positive connection of at least two hub sections can be achieved by appropriately shaping the opening structure of the peripheral wall 21.

[0338] Fig. 2d shows three interconnected hub sections 20a, 20b, and 20c. Due to the design of the end faces 31 and 32 of the respective hub sections, projections from adjacent hub sections engage with each other. Specifically, the complementary projections 41 engage in free spaces 42 of the adjacent end faces.

[0339] Fig. 2d also shows that the hub sections 20a, 20b, and 20c are arranged relative to one another in such a way that the adjacent end faces are serrated. A weld seam 38, which is applied between the hub sections 20a, 20b, and 20c to connect them, is Z-shaped or serrated.

[0340] It can also be seen that the outermost tips 46 of the end faces 31, 32 are not arranged in a plane perpendicular to the longitudinal axis. Rather, this plane E runs obliquely to the longitudinal axes L. This applies to both the first end face 31 of the hub section 20a and the second end face 32 of the hub section 20c.

[0341] Due to the plane E or the tips 46, a particularly good engagement of a first hub section into a second adjacent hub section can take place.

[0342] Figs. 2e and 2f show a further embodiment with respect to a monolithically formed hub section 20. This hub section also has triangular openings 22, a spirally extending, web-like wall section 25, and a first end face 31 and a second end face 32. The end faces 31 and 32 are complementary to one another, so that several similarly formed hub sections 20 can be positioned relative to one another in such a way that they can be connected to one another as shown in Fig. 2f.

[0343] The shape of the first and second end faces 31 and 32 follows the course of the spiral wall section 25 and is also formed by a web 40' which, together with another web 40, delimits an opening 22.

[0344] The end face 31 of the hub section 20 is formed from two end face sections. The first end face section 44, which follows the course of the spiral wall section 25, thus itself extends spirally relative to the longitudinal axis L of the hub section 20. The two ends of the spiral end face section 44 are connected to one another by means of the end face section 44', which in turn is formed by the web 40.

[0345] This shape applies to both end faces 31 and 32, so that the tip 46 of a first end face 31 formed by the two formed end face sections 44 and 44' can engage in the free space 42 in the region of the connecting edge 47 of the second end face 32 of an adjacent hub section.

[0346] Due to the shape of the complementary end faces 31 and 32, a positive fit is again achieved, creating an additional material connection. In this regard, at least one weld seam 38 is applied to connect two adjacent hub sections 20a, 20b. The weld seam 38 runs along the connecting joint or connection point defined by the end face sections 44 and 44'.

[0347] Fig. 3 shows a further embodiment of a monolithically formed worm hub section 20. This monolithically formed hub section has at least one worm screw base. The worm screw base 81 is a partial section of the monolithic basic structure of the hub section 20. According to the embodiment of Fig. 3, the worm screw base 81 is not applied to the hub section 20 in a separate manufacturing process. The additional worm screw blade, however, can be applied to this worm screw base 81 in a separate process. If the additional worm screw section is formed from a sheet metal, it can be welded to the worm screw base 81. Welding the worm screw blade separately is also possible.

[0348] If several hub sections 20, as shown in Fig. 3, have a worm helix root 81, these hub sections are to be joined together to form a complete worm helix root of the longitudinal section of the worm hub. This facilitates the complete application process with regard to the formation of a worm helix.

[0349] Alternatively, it is possible for the monolithically formed hub section to already have a complete screw flight in sections. By joining several hub sections of this design, the complete screw flight of the centrifuge screw according to the invention can thus already be present.

[0350] Figs. 4a and 4b show a further embodiment with respect to a monolithically formed hub section 20. This hub section 20 also has a wall 21 with openings 22 formed therein. The formation of a spiral-shaped wall section 25 can also be seen.

[0351] The monolithically formed hub section 20 has a plurality of webs 40 that delimit the openings 22 of the peripheral wall 21, with at least two webs 40 being connected to each other and forming a node 48. Four such nodes 48 are formed on the first end face 31. Four such nodes 48 are also provided on the second end face 32. Furthermore, a partial section 49 of the spiral-shaped wall section 25 can be seen.

[0352] Fig. 4a also serves as an example of the arrangement of additional bulging sections. In particular, at least one additional bulging section can be formed on the inner side 37 of the peripheral wall 21 in a transition region 27 from the inner side 37 of the peripheral wall 21 to a side surface 28 that at least partially delimits an opening 22 in the peripheral wall 21. The side surface 28 is a side surface of a web 40. Furthermore, at least one additional bulging section can be formed on the outer side 39 of the peripheral wall 21 in a transition region 26 from the outer side 39 of the peripheral wall 21 to a side surface 28 that at least partially delimits an opening 22 in the peripheral wall 21. The side surface 28 is a side surface of a web 40.

[0353] In Fig. 4a, only transition regions 26 and 27 are shown, which in the direction of rotation R of the hub portion 20 represent the first transition regions in relation to the openings 22. However, bulged sections can be or are preferably formed on all transition regions formed in the circumferential direction U between the outer side 39 and the side surfaces 28, as well as between the inner side 37 and the side surfaces 28.

[0354] As can be seen in Fig. 4b, the hub sections 20a and 20b, or 20b and 20c, are each connected, in particular welded, to one another at the nodes 48 formed on the end faces. Two interconnected nodes 48 each form a node 43 of a longitudinal section of the screw hub of at least four webs 40 to be connected. The hub sections 20a, 20b, and 20c are designed in such a similar manner that an open wall structure of a longitudinal section of a screw hub can be formed, since the alignment of the nodes 48 and any partial section 49 can be such that they abut complementary sections of an adjacent hub section.

[0355] This formation of a monolithically shaped hub section serves in particular to provide identical parts that can be connected to one another in a simple manner.

[0356] As shown in Fig. 5a and 5b, at least one hub section 20a and / or 20b can be formed from at least two monolithic segments 90. An exemplary segment 90 is shown in Fig. 5a. The segment 90 forms a radial partial section of the circumferential wall 21 of the hub section and preferably extends over the entire longitudinal extent of a hub section 20. The monolithic segment in turn has openings 22, preferably in triangular and quadrangular shapes. A wall section 25 that runs spirally at least in sections can also be seen. Furthermore, two abutting surfaces 91 can be seen, which do not run in a common plane but rather at an angle to one another.

[0357] In relation to the longitudinal axis L of the hub section 20, the abutting surfaces 91 have an opposing oblique course. This enables a preliminary loose connection of the two segments 90 to one another when the two segments 90 are joined together. It is also possible to form the connection of the segments 90 with a positive fit, so that a subsequent joining step, in particular the production of a welded joint, could be simplified. The two monolithic segments 90, preferably all of the segments 90 shown in Fig. 5b, are formed as cast bodies. This simplifies the manufacturing process.

[0358] The longitudinal section with an open wall structure shown in Fig. 5b can, for example, be created by first producing hub sections 20a and 20b. For this purpose, the segments 90 are first connected to one another, with the hub sections 20a and 20b being connected to one another in a subsequent step.

[0359] Within the scope of an automated joining process, it is also possible for all segment parts to be connected to one another step by step by appropriate clamping of the segments 91, whereby no distinction is made as to whether a hub section 20a, 20b is produced first or, for example, a circular weld seam 38 is first applied between the hub sections 20a and 20b.

[0360] Fig. 5c shows another exemplary segment 90. This segment 90 can itself serve to form hub sections 20a and 20b, as shown in Fig. 5b.

[0361] The segment 90 according to Fig. 5c forms a partial section of the peripheral wall 21 of the hub section in the circumferential direction of a worm hub and preferably extends over the entire longitudinal extent of a hub section 20.

[0362] The monolithic segment 90 has openings 22. A wall section 25, which at least partially extends spirally, can also be seen. Furthermore, two abutting surfaces 91 are indicated. With regard to the abutting surfaces 91, it is possible that they may not extend in a common plane, but rather at an angle to one another. In relation to the longitudinal axis L of the hub section 20, such abutting surfaces 91 preferably have an oppositely inclined course. This enables a preliminary loose connection of the segments 90 to one another when joining corresponding segments 90.

[0363] Compared to the webs 40 of the peripheral wall 21 shown in Fig. 5a, the embodiment according to Fig. 5c has rod-shaped peripheral wall sections 92a, 92b. It can be seen that two rod-shaped peripheral wall sections 92a and 92b are aligned with each other. The paired rod-shaped peripheral wall sections 92a and 92b are separated from each other by the spiral wall section 25. The paired rod-shaped peripheral wall sections 92a and 92b each form a long rod-shaped peripheral wall section 92.

[0364] It can also be seen that the rod-shaped peripheral wall sections 92, 92a, 92b extend substantially in the longitudinal direction of the hub section to be formed. This does not correspond to an exact longitudinal orientation, but rather the rod-shaped peripheral wall sections 92a and 92b are arranged or aligned at an angle to the longitudinal direction. In this case, the angle is a maximum of 20°. If two rod-shaped peripheral wall sections 92a and 92b are aligned with each other, both rod-shaped peripheral wall sections 92a and 92b are positioned at the same angle to the longitudinal direction.

[0365] If several hub sections are formed from several segments 90 as shown in Fig. 5c, it is advantageous to position the hub sections 20a, 20b relative to one another in such a way that the rod-shaped peripheral wall sections are arranged in alignment with one another over several hub sections.

[0366] Fig. 6 shows a transition piece 50, which can be used for selectively connecting hub sections. The transition piece 50 preferably serves to connect a first hub section with a first outer diameter to a second hub section with a second outer diameter, wherein the two outer diameters are different. The transition piece 50 enables, in particular, a modular construction of a screw hub of a screw centrifuge according to the invention, wherein several differently designed hub sections can be connected to one another.

[0367] The transition piece 50 is preferably designed as a cast body so that several transition pieces can be manufactured and stored.

[0368] The transition piece 50 has a wall 52 into which openings 55 are formed. The openings 55 serve in particular to create an axial flow. The openings 55 can thus also be referred to as axial flow openings. This allows a fluid connection to be established between the interior of a screw hub section, which is formed in particular in the region of the open wall structure, and the interior of the bowl of a solid bowl screw centrifuge.

[0369] In the present example, an end face 56 is also formed, which closes the transition piece 50 in this area. This prevents, for example, flow from a screw hub section associated with the open wall structure to the screw hub interior in the area of ​​a solids discharge side section.

[0370] The wall 52 essentially describes a conical shape, so that the transition piece has a first outer circumference 57 and a second outer circumference 58. This serves, in particular, to connect hub sections with different outer diameters. It is possible for the transition piece 50 to have a balancing section. This can specifically involve the formation of a wall section that is necessary to eliminate an imbalance in the transition piece 50 based on previous calculations.

[0371] Fig. 7 shows a monolithically formed hub section 20 having a circumferential wall 21 with webs 40, openings 22, and a spiral wall section 25. The end faces 31 and 32 in the present case are formed by annular end surfaces. A balancing section 60 is also indicated. In contrast to the opening 22' shown, this balancing section 60 is an explicitly provided circumferential wall section that is designed to compensate for a previously calculated imbalance. A balancing section is therefore an additionally applied circumferential wall section. In this case, material savings are specifically dispensed with in order to compensate for a structurally determined or simulated imbalance due to the additional wall material.Alternatively or additionally, it is possible to dispense with the formation of a material section at at least one point of the peripheral wall 21, specifically to form a type of recess / cutout so that a balance compensation can be achieved.

[0372] Fig. 8 shows a hub section 20, which forms a longitudinal section of a screw hub. The peripheral wall 21 forms a polygonal shape in a cross-section perpendicular to the longitudinal axis L of the centrifuge screw. In this case, the polygonal shape is a regular hexagon.

[0373] In Fig. 8, the hub section is formed from three segments 90. Each segment 90 is of identical design and has two corners 95. The corners 95 are rounded. In the present invention, a polygonal shape or polygon shape also includes cross-sectional shapes whose corners are rounded.

[0374] The segments 90 are formed so as to lie against one another at abutting surfaces 91, wherein weld seams (not shown) can be formed in the grooves 96 to connect the individual segments 90.

[0375] The monolithic segments 90 each have webs 40 that define openings 22 of different shapes. Both triangular and quadrangular shapes are formed in the peripheral wall 21. Due to the polygonal shape, essentially flat side surfaces 98 are formed, in which the openings 22 are formed due to the webs 40.

[0376] Using a hub section 20 as shown in Fig. 8, a screw hub can be formed that is composed of several flat side surfaces and simultaneously has an open wall structure. Also in the case of the screw hub shown in Fig.

[0377] 8, it is advantageous to form a spiral wall section 25 which can serve as a fastening base for a screw helix and / or as a screw helix foot.

[0378] Finally, it should be noted that all features mentioned in the application documents and in particular in the dependent claims, despite the formal reference made to one or more specific claims, are intended to be protected independently, either individually or in any combination.

[0379] List of reference symbols

[0380] 10 Worm hub

[0381] 11 cylindrical longitudinal section

[0382] 12 solids discharge section

[0383] 13 storage section

[0384] 20a-e hub section

[0385] 21 peripheral wall

[0386] 22, 22' opening

[0387] 25 spiral wall section

[0388] 26 Transition section

[0389] 27 Transition section

[0390] 28 side surface

[0391] 31, 31' first front side

[0392] 32, 32' second front side

[0393] 33 First-class advantage

[0394] 34 Second kind of advantage

[0395] 35 sloping surface

[0396] 36 grooves

[0397] 37 Inside

[0398] 38 Weld seam

[0399] 39 Outside

[0400] 40, 40' jetty

[0401] 41 lead

[0402] 42 open space

[0403] 43 Junction

[0404] 44, 44' frontal section

[0405] 45 rounded sections 46 tip

[0406] 47 Connecting edge

[0407] 48 Junction

[0408] 49 subsection

[0409] 50 transition piece

[0410] 52 wall

[0411] 55 Opening

[0412] 56 frontal area

[0413] 57 first outer circumference

[0414] 58 second outer circumference

[0415] 60 balancing section

[0416] 80 snail eggs

[0417] 81 Snail-shaped egg-foot

[0418] 90 monolithic segment

[0419] 91 Impact surface

[0420] 92, 92a, 92b rod-shaped peripheral wall section

[0421] 95 Corner

[0422] 96 grooves

[0423] 98 side area

[0424] 100 centrifuge screws

[0425] E Level

[0426] L Longitudinal axis

[0427] LN Length of hub section

[0428] LR longitudinal direction

[0429] R Rotation direction

[0430] U circumferential direction

Claims

Claims 1. Centrifuge screw (100) comprising a screw hub (10) which has at least one longitudinal section with an open wall structure, wherein the longitudinal section has at least two interconnected, respectively monolithically formed hub sections (20), wherein each monolithically formed hub section (20) has a peripheral wall (21) and two end faces (31, 32) and a plurality of openings (22) are formed in the peripheral wall (21), characterized in that at least two mutually abutting hub sections (20) are connected to one another at least in sections, preferably completely, at the mutually abutting end faces (31, 32) by means of a positive connection and by means of a material connection, in particular by means of a welded connection.

2. Centrifuge screw (100) according to claim 1, characterized in that the positive connection is formed by projections (33, 34, 41) formed complementarily to one another on the abutting end faces (31, 32) of two hub sections (20).

3. Centrifuge screw (100) according to one of claims 1 to 2, in particular according to claim 2, characterized in that the shape of the positive connection and / or sections of the adjoining end faces (31, 32) form a groove (36), wherein the material connection, in particular at least one weld seam section (38), is formed at least in sections in the groove (36).

4. Centrifuge screw (100) comprising a screw hub (10) which has at least one longitudinal section with an open wall structure, wherein the longitudinal section has at least two interconnected, respectively monolithically formed hub sections (20), wherein each monolithically formed hub section (20) has a peripheral wall (21) and two end faces (31, 32) and in the A plurality of openings (22) is formed in the peripheral wall (21), characterized in that at least one of the monolithically formed hub sections (20), preferably all monolithically formed hub sections (20), has / have at least one screw helix foot (81) and / or one screw helix (80).

5. Centrifuge screw (100) comprising a screw hub (10) which has at least one longitudinal section with an open wall structure, wherein the longitudinal section has at least two interconnected, respectively monolithically formed hub sections (20), wherein each monolithically formed hub section (20) has a peripheral wall (21) and two end faces (31, 32) and a plurality of openings (22) are formed in the peripheral wall (21), characterized in that at least one monolithically formed hub section (20) has at least one balancing element and / or one balancing section (60).

6. Centrifuge screw (100) comprising a screw hub (10) which has at least one longitudinal section with an open wall structure, wherein the longitudinal section has at least two interconnected, respectively monolithically formed hub sections (20), wherein each monolithically formed hub section (20) has a peripheral wall (21) and two end faces (31, 32) and a plurality of openings (22) are formed in the peripheral wall (21), characterized in that the monolithically formed hub sections (20) each have a plurality of webs (40) delimiting the openings (22) of the peripheral walls (21), wherein in each case at least two webs (40) of a monolithically formed hub section (20) are interconnected and form a node point (48), and wherein on in each case at least one end face (31,32) of a monolithically shaped hub section (20) a plurality of nodes (48) are formed and the at least two interconnected monolithically shaped hub sections (20) are connected to one another at least in sections at nodes (48) formed on the end face, in particular, welded.

7. Centrifuge screw (100) according to claim 6, characterized in that end-face formed nodes (48) of a first monolithically formed hub section (20), which are connected to end-face formed nodes (48) of a second adjacent monolithically formed hub section (20), form a node (43) of at least four webs (20).

8. Centrifuge screw (100) comprising a screw hub (10) which has at least one longitudinal section with an open wall structure, wherein the longitudinal section has at least two hub sections (20) connected to one another, wherein each hub section (20) has a peripheral wall (21) and two end faces (31, 32) and a plurality of openings (22) are formed in the peripheral wall (21), wherein at least one hub section (20) is formed from at least two monolithic segments (90), wherein each monolithic segment (90) forms a radial and / or outer circumferential section of the peripheral wall (21) and preferably at least one monolithic segment (90) extends over the entire longitudinal extent of the at least one hub section (20).

9. Centrifuge screw (100) according to claim 8, characterized in that at least two hub sections (20) are each formed from at least two monolithic segments (90), wherein each monolithic segment (90) forms a radial and / or outer circumferential section of the circumferential wall (21) of the respective hub section (20).

10. Centrifuge screw (100) according to claim 8 or 9, characterized in that at least one monolithic segment (90), in particular all monolithic segments (90), is / are designed as a cast body.

11. Centrifuge screw (100) comprising a screw hub (10) which has at least one longitudinal section with an open wall structure, characterized in that the peripheral wall (21) of the screw hub (10) has a polygonal shape, in particular a regular polygonal shape, at least in sections in a cross-section perpendicular to the longitudinal axis (L) of the centrifuge screw.

12. Centrifuge screw (100) according to claim 11, characterized in that the polygon shape is a hexagon.

13. Centrifuge screw (100) according to one of the preceding claims, characterized in that at least one of the optionally monolithically formed hub sections (20), preferably all of the optionally monolithically formed hub sections (20), does not have a transverse disc.

14. Centrifuge screw (100) according to one of the preceding claims, characterized in that at least one of the monolithically formed hub sections (20), preferably all monolithically formed hub sections (20), is / are designed as a cast body.

15. Centrifuge screw (100) according to one of the preceding claims, characterized in that the screw hub (20) has at least in sections a tubular body longitudinal section (20a), wherein a transition piece (50), in particular a conically shaped one, is formed between the at least one tubular body longitudinal section (20a) and the open wall structure, wherein the transition piece (50) establishes a connection between a tubular body longitudinal section (20a) with a first outer diameter and the open wall structure with a second outer diameter, wherein the first outer diameter is preferably smaller than the second outer diameter.

16. Centrifuge screw (100) according to claim 15, characterized in that the transition piece (50) is designed as a cast body.

17. Centrifuge screw (100) according to one of the preceding claims, characterized in that a spiral-shaped wall section (25) is formed in the circumferential wall (21) of at least one, optionally monolithically formed, hub section (20), which wall section runs spirally in the circumferential direction (21) and forms at least one 120° rotation, in particular a > 360° rotation, particularly preferably a > 540° rotation or > 810° rotation, over the entire length (LN) of the optionally monolithically formed hub section (20).

18. Centrifuge screw (100) according to one of the preceding claims, in particular according to claim 17, characterized in that the openings (22) formed in the circumferential wall (21) of at least one, optionally monolithically formed, hub section (20) are arranged spirally in the circumferential direction (21) in such a way that, preferably between openings (22) adjacent in the longitudinal direction, at least one web-like wall section (25) is formed, which runs spirally in the circumferential direction (21) and forms at least one 120 ° rotation, in particular a > 360 ° rotation, particularly preferably a > 540 ° rotation or > 810 ° rotation over the entire length (LN) of the optionally monolithically formed hub section (20).

19. Centrifuge screw (100) according to one of the preceding claims, characterized in that at least one, optionally monolithically formed, hub section (20), preferably all, optionally monolithically formed, hub sections, has / have at least one screw flight foot (80) and / or one screw flight (81).

20. Centrifuge screw (100) according to one of the preceding claims, characterized in that the peripheral wall (21) of at least one, optionally monolithically formed, hub section (20) is at least partially - in the direction of the longitudinal axis (L) of the centrifuge screw (100) facing inner side (37), in particular in the direction of the longitudinal axis (L) and / or in the circumferential direction (U), and / or - has at least one bulge section on the outer side (39), in particular in the circumferential direction (U) and / or perpendicular to the longitudinal axis (L) to the outside.

21. Centrifuge screw (100) according to one of the preceding claims, characterized in that at least one, optionally monolithically formed, hub section (20) has rod-shaped peripheral wall sections (92, 92a, 92a) and / or webs (40, 40'), wherein the rod-shaped peripheral wall sections (92, 92a, 92a) and / or webs (40, 40') are round in cross section.

22. Centrifuge screw (100) according to one of the preceding claims, characterized in that the peripheral wall (21) of the screw hub (10) has a polygonal shape, in particular a regular polygonal shape, at least in sections in a cross section perpendicular to the longitudinal axis of the centrifuge screw.

23. Solid bowl screw centrifuge with a centrifuge screw (100) according to one of claims 1 to 22.

24. A method for producing a centrifuge screw (100), in particular a centrifuge screw (100) according to one of claims 1 to 22, comprising the steps: a) providing at least two, optionally monolithically formed, hub sections (20), wherein each, optionally monolithically formed, hub section (20) has a peripheral wall (21) and two end faces (31, 32) and a plurality of openings is formed (22) in the peripheral wall (21), b) positively connecting the at least two, optionally monolithically formed, hub sections (20), c) materially bonding, in particular welding, of at least two, optionally monolithically formed, hub sections.

25. The method according to claim 24, characterized in that in step a) the monolithically formed hub sections (20) are produced by means of a casting process.

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