Screw hub, centrifugal machine screw and full-cover type screw centrifugal machine

Abstract

The invention relates to a screw hub (20) for a centrifuge screw (10), comprising at least one integrally formed hub section (30), in particular at least two interconnected integrally formed hub sections (30), the at least one hub section (30) having a peripheral wall (31) and two end faces (33, 34) and a plurality of openings (32) being formed in the peripheral wall (31), the hub section (30) has at least one transverse disc (40).

Description

Technical Field

[0001] The invention relates to a screw hub for a centrifuge screw according to claim 1, comprising at least one integrally formed hub section, in particular at least two integrally formed hub sections connected to one another. The invention further relates to a centrifuge screw according to claim 14 with a screw hub according to the invention. The invention further relates to a fully covered screw centrifuge according to claim 15. Background Art

[0002] Fully covered screw centrifuges are characterized by a closed or completely covered drum. The drum rotates at a high speed, whereby a multiphase mixture located in the drum can be separated into at least one heavy phase and one light phase. The heavy phase is usually a solid phase, which is drawn out of the drum by means of a screw, i.e. a centrifuge screw. For this purpose, the screw is supported in the drum rotatably relative to the drum and has a screw spiral. The screw spiral is fastened directly or indirectly to the screw hub and spirally surrounds the screw hub.

[0003] The screw spiral sweeps along the inner side or inner cover of the drum and thus conveys the heavy phase material to the axial end area 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 purified is therefore located between the inner side of the drum and the screw hub.

[0004] In certain full-cap screw centrifuges, large sump depths are required, in particular for purification reasons, but at the same time this sump depth is limited by the diameter of the screw hub and the lift-off and sedimentation effects of the mixture or light phase to be purified that occur there.

[0005] On the other hand, efforts are constantly being made to construct screw hubs with sufficient or increased rigidity.

[0006] The pool depth can be increased by configuring the screw hub in particular to be permeable to the medium, but this may weaken the structure of the screw hub to a certain extent. Summary of the invention

[0007] It is therefore an object of the present invention to provide a screw hub for a centrifuge screw which, due to an improved structural design, has increased rigidity and at the same time improved flow characteristics.

[0008] Furthermore, the object of the invention is to enable a modular design of the screw hub, so that the dimensions of the screw hub, in particular the longitudinal extension, can be configured in accordance with the modular principle.

[0009] Furthermore, the object of the present invention is to provide a screw hub and a full-cover screw centrifuge.

[0010] According to the invention, this object is achieved with respect to the screw hub by the solution of claim 1. With respect to the centrifuge screw, this object is achieved with respect to the solution of claim 14. With respect to the full-cover screw centrifuge, this object is achieved with respect to the solution of claim 15. The dependent claims include at least suitable embodiments and improvements.

[0011] In particular, the object is achieved by a screw hub for a centrifuge screw, which comprises at least one integrally formed hub section, in particular at least two integrally formed hub sections connected to one another. The screw hub extends along a longitudinal axis. The longitudinal axis also forms the longitudinal axis of the centrifuge screw or the full-cover screw centrifuge.

[0012] The at least one hub segment has a circumferential wall and two end faces. A plurality of openings are formed in the circumferential wall, wherein the hub segment, in particular the at least one hub segment, has at least one transverse disk.

[0013] The screw hub according to the invention combines several advantages due to the novel design of at least one, preferably at least two, hub segments connected to one another. Due to the one-piece design, the hub segment has a particularly high rigidity. At the same time, due to the multiple openings, large pool depths can be achieved. Since at least one transverse disk is part of the integrally formed hub segment, this simplifies the production of the hub segment, since the transverse disk does not have to be connected to the hub segment in a separate process, but is already part of the screw hub.

[0014] In particular, a hub section that is designed in one piece and seamlessly is to be understood to mean a hub section that is formed in one piece.

[0015] The longitudinal direction of the screw hub is substantially defined by the orientation of the longitudinal axis of the screw hub.The longitudinal axis of the screw hub is the axis about which the screw hub rotates in use.

[0016] The longitudinal direction is preferably defined as the transport direction of the solid discharge.

[0017] In the longitudinal direction of the centrifuge screw, the centrifuge screw can have at least two different sections. In this case, the first section is a cylindrical longitudinal section. The other section that follows in the longitudinal direction is a section on the solid discharge side. The section on the solid discharge side can be designed, for example, conical or biconical or tubular compared to the cylindrical longitudinal section with a smaller diameter.

[0018] The medium to be processed or separated by means of a centrifuge screw can be a multiphase medium. The medium can be, for example, a 2-phase mixture or a 3-phase mixture. The screw hub according to the invention can also be used for a centrifuge screw to separate a 3-phase mixture, in which there is a solid phase and two liquid phases.

[0019] The integrally formed hub segment is preferably one of the hub segments of a screw hub. In other words, the screw hub is preferably formed from a plurality of, i.e. at least two, hub segments connected to one another. In a particularly preferred embodiment of the invention, the screw hub is formed from at least two integrally formed hub segments, wherein the two integrally formed hub segments have the features according to the invention, i.e. the two hub segments preferably have a peripheral wall and at least two end faces, and a plurality of openings are formed in the peripheral wall and each hub segment also has at least one transverse disk.

[0020] It is possible that the at least two integrally formed hub segments are designed differently with respect to their features according to the invention. This means that the at least two integrally formed hub segments each have a transverse disk, but these transverse disks are arranged at different positions relative to the longitudinal extension of the respective hub segment. Furthermore, the at least two integrally formed hub segments can differ from one another with respect to their openings (e.g. arrangement, number, shape).

[0021] In other words, it is possible that the screw hub can be assembled or manufactured by a plurality of hub segments formed in the same manner. For this purpose, the hub segments formed in one piece of the same manner are connected to one another.

[0022] In particular, the hub segments can be connected to one another in a material-locking and / or force-locking manner. In particular, a welded connection is suitable for a material-locking connection. On the one hand, this allows a stable connection of the hub segments. On the other hand, it is a relatively simple method for connecting the hub segments, wherein the corresponding welding process can also be carried out automatically.

[0023] When the hub segments are connected in a force-locking manner, especially during a threaded connection, the hub segments can be easily and quickly released and thus replaced, for example due to wear. In addition, this connection of the hub segments allows a modular design of the screw hub that can be easily realized, so that the screw hub can be easily manufactured in different structural sizes or structural lengths.

[0024] In a particularly preferred embodiment of the invention, the plurality of openings in the peripheral wall are formed as part of the overall shape of the hub segment. In other words, the openings are not openings which are subsequently provided in the peripheral wall, but the overall shape of the hub segment already has these openings. In other words, the integrally formed hub segment is formed such that, due to the manufacturing process, it already has its final shape. Therefore, no additional post-processing steps for forming, such as milling processes, are necessary.

[0025] The openings of the peripheral wall can have different shapes or geometries. For example, the openings can have essentially a triangular shape and / or a quadrilateral shape. In particular, it is possible that the openings of the hub section can vary in size and shape, i.e. be configured differently. This makes it possible to form a peripheral wall with an optimal distribution of the openings, in particular with regard to providing a web-shaped, in particular helically extending wall section, which serves to tighten the screw helix.

[0026] The opening of the peripheral wall can be limited by pillar-shaped and / or web-shaped elements. In other words, the geometric structure or shape of the opening can be formed by pillar-shaped and / or web-shaped elements.

[0027] The web-shaped element can be, at least in sections, a web-shaped wall section or a subsection of a web-shaped wall section, which serves to fasten the screw turn. Preferably, each opening is formed by at least one subsection of a web-shaped wall section and at least two struts, wherein struts are preferably defined as wall sections which serve only to delimit the opening and do not form or have an additional wall section for fastening the screw turn.

[0028] Furthermore, it is possible that the opening can be formed by two partial sections of one or more web-shaped wall sections and at least two struts.

[0029] In a preferred embodiment of the invention, the opening has a triangular shape, wherein two triangular openings are arranged relative to each other in such a way that the two openings form a rhombus shape. In a particularly preferred embodiment of the invention, the hub segment has a plurality of openings with a triangular shape, wherein two such openings each together form a rhombus shape. The rhombuses are again arranged offset from each other in the hub segment. In a particularly preferred embodiment of the invention, a web-shaped wall segment (which serves to tighten the screw helix) in this case extends through the node of the strut. This configuration of the hub segment enables a particularly stable and at the same time lightweight construction of the hub segment.

[0030] The length of the integrally formed hub segment 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 segment. With such a length / diameter ratio, an integrally formed hub segment can be provided, with which the screw hub can be formed from a plurality of preferably identical or identical integrally formed hub segments.

[0031] In a possible embodiment of the invention, the at least one transverse disk is formed on an end side of the hub segment. The end side of the hub segment is one of the two end sides of the hub segment which close the circumferential wall in the longitudinal direction of the hub segment.

[0032] The configuration of the transverse disk only on one end side of the hub segment has the advantage that material can be saved in the configuration of the transverse disk. By connecting a plurality of hub segments, a transverse disk can be formed between two hub segments to be connected.

[0033] In a further embodiment of the invention, a transverse disk can be formed on each of the two end sides of the hub segment. This in turn has the advantage that the hub segment formed in this way can be formed at any position of the screw hub to be formed. This means that the hub segment formed in this way can also form the end piece of the cylindrical longitudinal section of the screw hub. This applies not only to the end piece on the output side of the cylindrical longitudinal section of the screw hub, but also to the end piece on the input side of the cylindrical longitudinal section of the screw hub.

[0034] In a construction in which a hub segment has two transverse disks, the corresponding transverse disks can be constructed with a relatively thin material thickness, since when two such integrally formed hub segments are connected, a common transverse disk with a correspondingly greater material thickness can be formed due to the fact that preferably at least two transverse disks abut against one another.

[0035] In a further embodiment of the invention, the at least one transverse disk of the at least one integrally formed hub segment can be configured in the longitudinal direction of the hub segment at a position which substantially corresponds to the length bisector of the hub segment length. A position which substantially corresponds to the length bisector of the hub segment length is to be understood in particular as a position which is configured centrally with respect to the length of the hub segment. This need not, even for manufacturing reasons, correspond 100% precisely to the length bisector of the length. Slight deviations are possible here, in particular deviations of ±10%, in particular ±5%.

[0036] When constructing a plurality of hub segments of this type, which have at least one transverse disk at a position which corresponds essentially to the length bisector of the hub segment length, in particular to the length bisector of the hub segment length, the end faces of the hub segments need not necessarily be constructed in a plane which is constructed perpendicularly to the longitudinal axis of the hub segment. Rather, it is possible for the end faces to be constructed obliquely or helically or overlappingly in comparison with adjacently arranged hub segments. In this embodiment of the invention, two integrally formed hub segments to be connected can also be connected to one another by means of a connecting section, for example a weld seam, which does not correspond to a circular seam.

[0037] The shape of such a hub section with, for example, an inclined end corresponds to the shape of an obliquely sectioned cylinder. The inclined surface can be formed on both end sides or end faces of the hub section. It can also be formed only on one side, if, for example, the hub section in question is formed or positioned as an end section of a cylindrical longitudinal section of the screw hub.

[0038] It is possible that a plurality of integrally formed hub segments with overlapping and / or inclined and / or spiral end sides forming a screw hub are arranged and constructed complementary to one another in such a way that they are constructed to interlock with one another, thereby enabling a particularly advantageous connection in terms of rigidity of adjacent or side-by-side arranged hub segments.

[0039] It is possible that the screw hub can be composed of a plurality of hub segments that are differently designed with respect to the arrangement of the transverse disks. Thus, for example, it is conceivable that the hub segments that are designed centrally with respect to the cylindrical longitudinal segment are each designed with two transverse disks, which are each designed on one end side of each individual hub segment. In contrast, the hub segments that are arranged at the end sides can, for example, be designed with only one transverse disk. It is possible here to design the transverse disk only on one end side of the hub section or, for example, at a position that substantially corresponds to the length bisector of the length of the hub segment.

[0040] In the context of the present application, a hub segment is not to be understood as an integrally formed hub segment which consists essentially of a tube in which a plurality of openings are subsequently introduced into the circumferential wall. Rather, the term integrally formed should relate to hub segments of the type whereby, based on a correspondingly selected manufacturing process, the hub segment shape including the formation of the openings and the formation of the at least one transverse disk is formed based on a single manufacturing process or manufacturing step.

[0041] The at least one transverse disk is preferably designed in an annular shape. The annular design makes it possible, for example, for the inlet pipe of a full-cap screw centrifuge to be passed through such a transverse disk. Furthermore, the annular shape can result in liquid being able to flow through the opening formed in the center of the transverse disk. Preferably, the annular transverse disk has an annular width which corresponds to at most half the radius of the outer circle of the transverse disk.

[0042] In a further embodiment of the invention, the transverse disk can have at least one opening which is formed in the center point of the transverse disk. The opening can be circular, for example. It is also possible that the opening can be elliptical or flower-shaped. Preferably, the opening of the transverse disk has such a shape that the inlet pipe of the full-cover screw centrifuge can be passed through the opening.

[0043] In a further embodiment of the invention, it is possible that the transverse disk of at least one hub section has a plurality of openings formed on the periphery. The openings are thus formed in this case such that a preferably circular peripheral edge is interrupted by a plurality of openings. Preferably, the openings are evenly distributed in the circumferential direction of the transverse disk. This enables, for example, the passage of liquids. In this case, it is also conceivable to introduce additional struts or reinforcing rods.

[0044] In a further embodiment of the invention, the at least one transverse disk can have a plurality of openings arranged distributed in the circumferential direction. Preferably, the openings are evenly distributed in the circumferential direction of the transverse disk. In other words, for example, the annular shape of the transverse disk can have a plurality of evenly distributed openings. Such openings allow the passage of liquids. The openings arranged distributed in the circumferential direction can be designed, for example, circularly or quadrilaterally or triangularly. The actual shape of the openings can be selected depending on the flow rate to be achieved. It is possible that the at least one transverse disk has a plurality of the above-mentioned features and / or embodiments.

[0045] Due to a specially selected manufacturing process, the transverse disk can have a variable thickness in its monolithic structure. Individual sections of the transverse disk can thus be constructed with a greater material thickness or a greater thickness, so that the transverse disk forms a reinforcement section at these locations. In particular, such locations of the transverse disk with a greater thickness can be designed as a reinforcing strut. For example, the thickness of the transverse disk can decrease from the radial outside to the radial inside. Furthermore, it is possible for sections of the transverse disk with an increased thickness or material thickness compared to the remaining sections of the transverse disk to be arranged radially from a (virtual) center point of the transverse disk to the radial outside.

[0046] The openings formed in the peripheral wall can be arranged in a spiral shape in the circumferential direction so that at least one web-shaped wall section is preferably formed between the openings adjacent in the longitudinal direction, which wall section extends in a spiral shape in the circumferential direction and forms at least a 120° rotation, in particular a 180° rotation or a 360° rotation over the entire length of the hub section. The at least one web-shaped wall section, which extends in a spiral shape in the circumferential direction, is used in particular as a fastening surface for a screw spiral to be fastened to the screw hub. The web-shaped wall section, which extends in a spiral shape in the circumferential direction, has the advantage that the screw spiral can be easily connected to the screw hub in an automated process, in particular in an automated welding process.

[0047] Due to the preferred embodiment of such a helically extending wall segment that rotates by at least 120°, in particular 180° or 360°, a plurality of integrally formed hub segments can be combined and connected to one another in a simple manner, so that the screw spiral is preferably wound with a constant pitch around the screw hub formed by the plurality of hub segments.

[0048] The spiral arrangement of the openings in the peripheral wall is preferably understood to mean that the openings form a spiral shape as a whole. This is achieved, for example, by different opening geometries and / or opening sizes and / or by staggered arrangements of the openings in the longitudinal direction and / or circumferential direction of the hub segment.

[0049] The helical arrangement of the openings is preferably configured such that the openings and / or the struts or strut-like elements delimiting the openings are positioned such that when connecting at least two hub segments, the opening structure or the strut structure is also configured continuously.

[0050] Particularly preferably, when a plurality of hub sections are connected, both the web-shaped wall sections and the opening structures or strut structures extend continuously or at the same inclination. A screw hub formed in this way achieves a particularly good cleaning effect.

[0051] In a further embodiment of the invention, the integrally formed hub section has a plurality of webs which delimit the peripheral wall openings, wherein the webs, in particular the webs and the at least one web-shaped wall section, respectively extend in the longitudinal direction of the screw hub and transversely to the longitudinal direction. With the aid of such a web arrangement, a helical arrangement of the openings in the peripheral direction can be achieved in a structurally simple manner.

[0052] In a further embodiment of the invention, such a number of openings are formed in the peripheral wall and / or the openings of the peripheral wall have such an opening cross section that the peripheral wall is formed as an open wall structure.

[0053] An open wall structure is to be understood in particular as a wall structure which has a large number of openings and / or an overall high opening area in the relevant hub section. The opening area is to be understood in particular as the sum of all individual opening areas of the individual openings in the relevant hub section. In other words, the opening area does not have to be a continuous single opening area.

[0054] Preferably, the value of the open area is greater than the value of the closed area. The closed area is understood to be that part of the wall structure which is closed and does not allow material to pass from the interior of the screw hub to the outside (or vice versa). More preferably, the closed area is understood to be the sum of all individual closed areas in the circumferential wall of the hub segment.

[0055] Furthermore and / or additionally, such a wall structure of the hub section with a high proportion of openings in the circumferential direction can be understood as an open wall structure. Preferably, the proportion of openings is higher than the proportion of closed areas. Preferably, the proportion of openings in the circumferential direction of the screw hub is at least 50%, further preferably at least 60%, particularly preferably at least 65%, further particularly preferably at least 80% of the entire wall structure in the circumferential direction.

[0056] Particularly preferably, the portion of the opening is formed in the circumferential direction over the entire longitudinal extension of the open wall structure. In the sense of the invention, a longitudinal extension is understood to be an extension of a component, section, etc., which extends substantially in a direction preferably parallel to the longitudinal axis of the screw hub and / or the centrifuge screw.

[0057] 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 the above definition.

[0058] The construction of an open wall structure facilitates the creation of a large pool depth in a fully enclosed screw centrifuge.

[0059] In a particularly preferred embodiment of the invention, the at least one integrally formed hub segment is designed as a cast body. In other words, the integrally formed hub segment is manufactured by means of a casting method. Standard casting materials can be used here. In general, very complex structures with respect to the hub segment can be manufactured by means of a casting method. Compared to a manufacturing method based on subsequent milling of an opening or by welding together a plurality of rod elements or components, the manufacturing of the hub segment by a casting method is simpler and more cost-effective.

[0060] When a casting method is used, the at least one hub segment preferably consists of chromium-nickel steel and / or dual-phase steel and / or nickel-based steel.

[0061] In a particularly preferred embodiment of the invention, the at least one integrally formed hub segment can be produced by a wax melting method.

[0062] In the context of a casting method, in particular a wax melting method, it is possible to produce the individual sub-segments of the at least one integrally formed hub segment with different casting quality levels. The casting quality level to be achieved for the individual sub-segments can therefore be selected depending on the subsequent component loads and / or the material stresses that are acting.

[0063] Furthermore, the individual subsections of the at least one integrally formed hub section can be produced or formed with different wall thicknesses within the scope of a casting method, in particular a wax melting method. In other words, the individual subsections of the at least one integrally formed hub section can have different wall thicknesses. The wall thickness can be selected as a function of the subsequent component loads and / or the material stresses that are acting.

[0064] A plurality of hub segments can be formed by means of one casting mold.

[0065] In a further embodiment of the invention, the at least one integrally formed hub segment can be manufactured by means of a 3D printing method. When manufacturing by means of a 3D printing method, complex shapes or structures of the hub segment can also be designed. Based on the 3D printing method, all segments and partial regions of the hub segment can be manufactured by means of a single manufacturing step without the need for post-processing, such as subsequent opening by means of a milling process.

[0066] When using a 3D printing method, the at least one hub segment preferably consists of chrome-nickel steel and / or dual-phase steel and / or nickel-based steel.

[0067] The 3D printing method can be carried out, for example, by means of a shaping additive material application. The shaping additive material application can be carried out, for example, by means of a shielded gas welding device, wherein the shielded gas welding device is preferably operated with a welding gas and the welding gas is selected from a subgroup of main groups I, M1, M2 or N of the standard DIN EN ISO 14175.

[0068] Preferably, welding is performed using an active reactive welding gas or an inert welding gas. Such welding methods may also be referred to as MAG or MIG welding or welding with active or inert gases. Such welding methods are generally referred to as metal shielded gas welding methods (MSG).

[0069] Main group 1 includes welding gases having 100 volume percent nominal argon (subgroup 1), 100 volume percent nominal helium (subgroup 2), and 0.5 to 95 volume percent nominal helium and the remainder argon (subgroup 3). These welding gases are completely inert.

[0070] Main group M1 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 remainder argon or helium. These welding gases are low oxidizing and only low reducing. Main group M1 subgroup 2 includes welding gases with 0.5 to 5.0 volume percent nominal carbon dioxide and the remainder argon or helium. These welding gases are low oxidizing. Main group M1 subgroup 3 includes welding gases with 0.5 to 3.0 volume percent nominal oxygen and the remainder argon or helium. These welding gases are also low oxidizing. Main group M1 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 remainder argon or helium. These welding gases are again low oxidizing.

[0071] Main group M2 subgroup 0 includes welding gases having 5.0 to 15.0 volume percent nominal carbon dioxide and the remainder argon or helium. These welding gases are low oxidizing. Main group M2 subgroup 1 includes welding gases having 15.0 to 25.0 volume percent nominal carbon dioxide and the remainder argon or helium. These welding gases are also low oxidizing. Main group M2 subgroup 2 includes welding gases having 3.0 to 10.0 volume percent nominal oxygen and the remainder argon or helium. These welding gases are also low oxidizing. Main group M2 subgroup 3 includes welding gases having 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. Main group M2 subgroup 4 includes welding gases having 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 having 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 having 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 having 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 relatively low oxidizing.

[0072] 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. These welding gases are inert at high argon or high helium contents, and these welding gases are only slightly reduced even with increasing hydrogen content.

[0073] In summary, it is therefore preferred to select an inert, low-oxidizing and / or low-reducing welding gas in a targeted manner. With such a method, it is possible to work with low-oxidizing welds and largely without slag in the case of structural welding or additive material application. This is particularly advantageous for stacking welds. In addition, it is possible to work with particularly fast welding rates. This firstly enables particularly short manufacturing times. However, the actual advantage of the fast welding rate is that the at least one integrally formed hub section is only slightly heated in a spot-like manner during welding and therefore only produces a small amount of warping or deformation.

[0074] A great advantage of the described procedure is that, in such structural welding, a particularly high wear resistance is achieved on the surface produced in this manner.

[0075] According to this exemplary embodiment, for example, a subsequent tempering treatment, in particular the application of a wearing layer, can be omitted.

[0076] For example, nominally, the welding gas has a carbon dioxide content of less than 20% by volume. This low carbon dioxide content makes it possible, in particular, to process structural steel by means of pulse welding. At the same time, a relatively high burnout of the welding wire is possible. This results in a high-quality structure and a particularly fast working method during welding. Furthermore, it is preferred to use a welding gas that nominally has an oxygen content of less than three% by volume as the welding gas. Such a welding gas is particularly low in oxidizing properties. Furthermore, welding gases with a high argon content are particularly inexpensive.

[0077] In an embodiment of the invention, the shielded gas welding device is operated with a pulsed arc. Such a pulsed arc allows the melting of the welding wire to be precisely controlled at the shielded gas welding device. In addition, the heat input into the at least one integrally formed hub section can be kept particularly low in a targeted manner. Therefore, deformations caused by temperature can be kept small. The welding current of such a pulsed arc welding device has, for example, a basic current of less than 200 amperes and a pulse current of more than 200 amperes. Such a welding current is advantageous in the case of particularly precise material constructions with relatively small heat introduction. Here, a welding gas with a nominal argon content of 98 volume percent and a nominal carbon dioxide content of 2 volume percent is advantageously used as the welding gas.

[0078] It is also particularly advantageous to operate the shielded gas welding tool with a short arc, in particular a short arc with reduced energy. Such a method with a short arc is also referred to as a cold arc, that is to say a method with a particularly cold arc. In order to achieve an arc that still has a high melting strength, it is particularly advantageous to operate with an increased melting current pulse.

[0079] The shielding gas welding tool is particularly advantageously operated with one welding wire or advantageously also with two welding wires (twin-wire welding method) having a diameter of 0.5 mm to 3.0 mm, preferably 1.0 mm to 1.6 mm.

[0080] Such a wire diameter enables high welding speeds and at the same time particularly low thermally induced deformations. Particularly preferred are individual welding layers or welding stacks with a width of 6 to 7 mm. If the profile is to be produced by means of the method according to the invention, the welding layer or welding stack has a width of at least 2 mm.

[0081] The at least one hub segment to be integrally formed can preferably be moved during production. With this movement, the at least one hub segment to be integrally formed is oriented at its welding location in such a way that an optimal position is obtained for the applied welding stack. In this case, the welding stack is particularly preferably applied on a horizontal surface.

[0082] It is also advantageous if the welding stack is applied to a surface that rises slightly in the welding direction. The angle of inclination is preferably between 5° and 15°, advantageously between 7° and 10°. Accordingly, the at least one hub segment to be integrally formed is preferably moved such that a horizontal welding surface or a welding surface that rises in the welding direction of the shielding gas welding device is present at the welding point of the shielding gas welding device.

[0083] The screw hub can have a plurality of, in particular two or three or four or five, hub segments connected to one another. These connected hub segments form a longitudinal segment of the screw hub, preferably the entire longitudinal segment of the screw hub. Thus, the cylindrical longitudinal segment of the screw hub can be formed by a plurality of, preferably identical or identical hub segments. This allows a screw hub to be assembled or spliced ​​together in a simple modular manner from a selectable number of hub segments.

[0084] In particular, the hub segments can be connected to one another in a materially and / or forcefully manner. With regard to the materially connected connection, a welded connection is particularly suitable in a particular manner and method. On the one hand, this allows a stable connection of the hub segments. On the other hand, it is a relatively simple method for connecting the hub segments, wherein the corresponding welding process can also be carried out automatically. When the hub segments are connected in a forcefully manner, in particular by tightening, the hub segments can be easily and quickly loosened, for example due to wear, and thus replaced. In addition, this connection of the hub segments allows a modular design of the screw hub, so that the screw hub can be easily manufactured with different structural sizes or structural lengths.

[0085] The hub segments are preferably connected to one another in such a way that the web-shaped wall segments of the individual hub segments, in particular the web-shaped wall segments according to dependent claim 6, are positioned relative to one another in such a way that a continuously spirally extending fastening segment for fastening the screw spiral is formed over the entire longitudinal section of the screw hub. This allows the screw spiral to be fastened to the screw hub reliably and automatically. In a further embodiment of the invention, a plurality of web-shaped wall segments can be formed in the peripheral wall. This allows a plurality of fastening segments to be formed for fastening a plurality of screw spirals.

[0086] The screw hub formed according to the invention advantageously makes it possible to replace or repair individual hub segments of the screw hub if they are defective or have signs of wear. This also applies to hub segments of the screw hub that were not initially designed according to the invention, wherein after the repair has been carried out, the screw hub has a hub segment of the screw hub according to the invention.

[0087] A further, parallel aspect of the invention relates to a centrifuge screw having a screw hub according to the invention and a screw spiral which is arranged circumferentially on the screw hub.

[0088] Preferably, the screw is screw-fastened on a helically extending fastening section of the screw hub. The at least one helically extending fastening section is preferably formed by a web-shaped wall section of the circumferential wall.

[0089] Possibly, the centrifuge screw has a plurality of screw spirals, in particular two screw spirals. In this case, at least two rib-shaped wall segments spaced apart from each other are constructed in the peripheral wall of the at least one hub segment, preferably a plurality of hub segments, so as to enable the fastening of the two screw spirals.

[0090] A further, parallel aspect of the invention relates to a full-cap screw centrifuge comprising a centrifuge screw in a drum, wherein the centrifuge screw is designed according to the invention and / or has a screw hub according to the invention.

[0091] With regard to the centrifuge screw and with regard to the fully enclosed screw centrifuge, reference is made to the advantages explained in connection with the screw hub.

[0092] The invention will be explained in more detail below with reference to the accompanying drawings.

[0093] The embodiment shown is an example of how to construct a screw hub according to the invention or a centrifuge screw according to the invention. In particular, the figures show an integrally formed hub segment which can form a screw hub according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0094] In the accompanying drawings:

[0095] Figure 1shows a longitudinal section of a centrifuge screw according to the invention;

[0096] Figures 2 to 4 Different embodiments are shown with regard to an integrally formed hub segment for forming a screw hub according to the invention. DETAILED DESCRIPTION

[0097] In the following, the same reference numerals are used for identical and identically acting components.

[0098] exist Figure 1 1 shows a centrifuge screw 10 according to the invention with a screw hub 20 according to the invention. The screw hub 20 has a cylindrical longitudinal section 11, a conical section 12 and a bearing section 13 in the longitudinal direction R. The sections 11, 12 and 13 have a longitudinal axis L as a common axis.

[0099] In the present case, the conical section 12 corresponds to the section on the solids side, provided that the centrifuge screw shown is designed as part of a full-cap screw centrifuge.

[0100] The bearing section 13 serves to accommodate a bearing, in particular a screw bearing, in order to rotatably support the screw hub 20 .

[0101] It is possible that in another embodiment of the present invention, the section 12 has a shape different from a simple cone. For example, the section 12 can be constructed as a cylindrical section and a cylindrical tube section. It is also possible that the section 12 has a double truncated cone shape. The cylindrical longitudinal section 11 of the screw hub 20 is arranged between the conical section 12 and the bearing section 13 in the longitudinal direction R. The sections 11, 12 and 13 are fixedly connected to each other.

[0102] The screw hub 20 is surrounded radially on the outside by the screw spiral 60. The screw hub 20 thus serves to support the screw spiral 60 in the radial direction, to transmit the torque from the drive to the screw spiral 60, and in particular to absorb tensile and thrust forces.

[0103] The longitudinal direction R extends substantially parallel to the longitudinal axis L of the screw hub 20. The longitudinal direction R is defined in the present case as the transport direction of the solid discharge. Figure 1 The diagram proceeds from right to left.

[0104] The cylindrical longitudinal section 11 is longer than the conical section or the solids discharge-side section 12. The section 12 of the screw hub 20 is understood to be a section which is used in particular to transport solids separated from the material to be processed in the direction R of the solids discharge.

[0105] In the illustrated example, the cylindrical longitudinal section 11 of the screw hub 20 is composed of four hub sections 30a, 30b, 30c, 30d. The integrally formed hub sections 30a, 30b, 30c and 30d are connected to each other, in particular welded to each other. The two hub sections 30b and 30c can be called central hub sections. These central hub sections are positioned between the end-side hub sections 30a and 30d. Therefore, the end-side hub section 30a forms the end part or end section of the cylindrical longitudinal section 11 facing the conical section 12. On the contrary, the end-side hub section 30d forms the end part or end section of the cylindrical longitudinal section 11, which points toward the bearing section 13 or toward the end of the screw hub 20 opposite to the conical section 12.

[0106] Each hub segment 30a-30d has a peripheral wall 31, in which a plurality of openings 32 are constructed. In addition, each hub segment 30a-30d has a transverse disk 40. The transverse disk 40 is constructed on the end side, that is, on the second end side 34 of the corresponding hub segment 30a-30d. A single hub segment 30a-30d has two end sides, namely a first end side 33 and a second end side 34. The end sides 33 and 34 define the longitudinal extension of the peripheral wall in the longitudinal direction R. The first end side 33 is the first end side of the corresponding hub segment 30a-30d in the longitudinal direction R. The second end side 34 forms the second end side of the corresponding hub segment 30a-30d constructed along the longitudinal direction R. The hub segments 30a-30d are connected to each other in this way, so that the second end side 34 of a hub segment is connected to the first end side 33 of the adjacent or adjacent hub segment 30a-30d.

[0107] The transverse disk 40 is therefore located in each case in the connecting region between the two hub sections.

[0108] The length LN of the respective hub segment 30a-30d is preferably 1 to 2 times the diameter D of the hub segment 30a-30d. In the present case, the respective hub segments 30a-30d are all constructed identically. This also relates to the length LN of the hub segment and the ratio thereof to the respective diameter D of the hub segment. In the illustrated longitudinal section of the screw hub 20, it can be seen that at least one web-shaped, helically extending wall segment 35 is constructed in the peripheral wall 31. The web-shaped wall segment 35 forms a bearing surface for the screw spiral 60 on the outwardly directed surface 36. On this bearing surface, the screw spiral 60 can be connected to the screw hub 20.

[0109] The web-shaped wall section 35 extends over the entire length LN of the hub section 30 in such a way that a rotation of at least 120° is formed. In the example shown, a rotation of more than 360° is formed. Since the hub sections 30a-30d are designed identically, the hub sections 30a-30d can be positioned relative to one another and fastened to one another in such a way that the individual web-shaped wall sections 35 form a web-shaped wall section that extends continuously with respect to the cylindrical longitudinal section 11 of the screw hub 20. The continuously extending web-shaped wall section of the cylindrical longitudinal section 11 preferably has a constant slope over the entire length of the cylindrical longitudinal section 11.

[0110] In the present case, the opening 32 of each hub segment 30a-30d has a triangular shape. Taking the hub segment 30d of the end side as an example, the triangular shape is formed by two pillars or pillar-shaped elements 37 and a sub-segment of a web-shaped wall segment 35. The two openings 32' are positioned relative to each other so that the two openings form a rhombus shape together. A plurality of rhombuses are arranged in the hub segment 30d staggered again. The web-shaped wall segment 35 (which is used to tighten the screw helix) extends through the node 38 of the pillar 37 in this embodiment. This construction of the hub segment 30d can realize a particularly stable and at the same time light structure of the hub segment 30d. In the example shown, all hub segments 30a-30d have the same basic structure.

[0111] exist Figure 2 A single integrally formed hub segment 30 is shown in FIG. Figure 1 The cylindrical longitudinal section 11 of the screw hub 20 can be formed. The perspective view shows in particular the design of the transverse disk 40. The transverse disk 40 is substantially annular in shape.

[0112] An annular surface is formed between the inner circular edge 42 and the outer circular edge 43 .

[0113] The opening 41 is formed in the center point M of the transverse disk 40 . The diameter of the opening 41 is formed by the inner circular edge 42 .

[0114] The ring width KB is preferably at most 50% of the radius r of the transverse disk 40 .

[0115] The opening 41 of the transverse disk 40 is used on the one hand for passing the introduction tube. This is necessary in particular when constructing the hub section 30, as long as it is arranged, for example, at the position of the screw hub 20 to form the hub section 30c or 30d (see Figure 1 In addition, the opening 41 is used for the passage of liquid.

[0116] Additional openings 44 are formed in the annular ring of the transverse disk. These openings are arranged evenly distributed in the radial direction of the transverse disk 40. These openings 44 also serve as passages for the liquid.

[0117] It has been found that a ring width KB having the indicated maximum dimension provides, on the one hand, sufficient stability and, on the other hand, forms the largest possible passage for the liquid.

[0118] The peripheral wall 31 of the hub section 30 is constructed with an open wall structure. That is, the peripheral wall 31 in the present case has a certain number of openings 32 and such an opening cross section of the openings 32 that the peripheral wall 31 as a whole can be referred to as an open wall structure. The openings 32 in the present case essentially have a triangular shape. The triangular shapes of the openings 32 are staggered and arranged alternately with each other, so that a web-shaped wall section 35 is constructed between the openings 32, which wall section extends helically in the circumferential direction.

[0119] The outwardly directed surface 36 of the web-shaped wall section 35 can be seen. The screw spiral 60 (not shown) can be fastened to the outwardly directed surface 36. The openings 32 are formed by struts 37 and subsections of the web-shaped wall section 35 to form the opening cross section, which is triangular in this case, wherein the struts 37 and the web-shaped wall section 35 each extend in the longitudinal direction R of the screw hub 20 and transversely to the longitudinal direction R. A hub section 30 of this shape can be produced in particular by means of a casting method, wherein the openings 32 are arranged offset to one another and alternately in shape.

[0120] exist Figure 3 2 shows an alternative embodiment of a hub segment 30. The hub segment 30 also has a transverse disk 40 on the end side, wherein the transverse disk 40 also has a circular ring shape.

[0121] The hub section 30 is connected to the Figure 2 The difference between the hub segments 30 of the embodiments of the embodiment lies in the shape of the openings 32 constructed in the peripheral wall 31. Each opening 32 is constructed in size and shape so that a wall segment 35 with a surface 36 pointing outward and extending in a spiral shape is formed. In order to form the wall segment 35 with a spiral extension, each opening 32 has different longitudinal extensions in the longitudinal direction R. In addition, the shapes of the openings 32 are different from each other. Each opening 32a basically has a quadrilateral basic structure. On the contrary, each opening 32b has a triangular shape. Thus, the segment of the peripheral wall 31 constructed between the end sides 33 and 34 and the web-shaped wall segment 35 is constructed to have an opening 32 as large as possible, wherein, at the same time, the spiral direction of the web-shaped wall segment 35 can be realized.

[0122] Figure 4 A further embodiment of the hub segment 30 is shown. The hub segment again has a transverse disk 40 on the end side 33. Figure 3As described in the embodiment of FIG. 1 , each opening 32 has a different opening shape. In addition to the triangular opening 32 b, a substantially quadrilateral opening 32 a is constructed.

[0123] The hub segment 30 has two web-shaped wall segments 35a and 35b. The web-shaped wall segments 35a and 35b extend helically and are spaced apart from one another. Due to the configuration of the two web-shaped wall segments 35a and 35b, a plurality of screw spirals 60 spaced apart from one another can be fastened to a screw hub. Both web-shaped wall segments 35a and 35b extend over the entire length LN of the hub segment 30 and each form a rotation of at least 120°.

[0124] By connecting a plurality of hub segments 30, as in Figure 3 As shown in , a screw hub 20 , in particular a cylindrical longitudinal section 11 of the screw hub 20 , can be formed which has a plurality of, in particular two, screw turns.

[0125] Due to the number and size of the formed openings 32a and 32b, an open wall structure is again formed. The openings 32a and 32b are formed by struts 37 and partial sections of the web-shaped wall sections 35a and 35b.

[0126] Finally, it should be pointed out that, despite formal reference to one or more specific claims, all features mentioned in the application documents and in particular in the dependent claims may also be protected independently, individually or in any combination.

[0127] Reference numerals list

[0128] 10 Centrifuge screw

[0129] 11 Cylindrical longitudinal section

[0130] 12 Conical sections

[0131] 13 Bearing section

[0132] 20 Screw hub

[0133] 30, 30a, 30b, 30c, 30d hub section

[0134] 31 Wall

[0135] 32, 32', 32a, 32b openings in the peripheral wall

[0136] 33 First end side

[0137] 34 Second end side

[0138] 35, 35a, 35b: web-shaped wall section

[0139] 36 Outward-pointing face

[0140] 37 Pillar

[0141] 38 nodes

[0142] 40 Horizontal plate

[0143] 41 Opening of the transverse plate

[0144] 42 Inner round edge

[0145] 43 outer round edge

[0146] 44 Distributed openings

[0147] 60 screw spiral

[0148] L Longitudinal axis

[0149] LN Length of the hub segment

[0150] D diameter of the hub section

[0151] R Longitudinal direction

[0152] r Radius of the transverse disk

[0153] M Center point of the horizontal plate

[0154] KB Ring width

Claims

1. A screw hub (20) for a centrifuge screw (10), comprising at least one integrally formed hub section (30), in particular at least two integrally formed hub sections (30) connected to one another, wherein: The at least one hub section (30) has a circumferential wall (31) and two end faces (33, 34), and a plurality of openings (32) are formed in the circumferential wall (31), wherein the hub section (30) has at least one transverse disk (40).

2. The screw hub (20) according to claim 1, characterized in that: The length (LN) of the hub section (30) is 0.5 to 3 times, in particular 0.75 to 2.5 times, in particular 1 to 2 times, the diameter (D) of the hub section (30).

3. The screw hub (20) according to claim 1 or 2, characterized in that: The at least one transverse disk (40) is formed on an end face (33, 34) of the hub section (30).

4. The screw hub (20) according to any one of claims 1 to 3, characterized in that The at least one transverse disk (40) is configured in the longitudinal direction (R) of the hub section (30) at a position which substantially corresponds to a length bisection point of a length (LN) of the hub section (30).

5. The screw hub (30) according to any one of the preceding claims, characterized in that The at least one transverse disk (40) is annularly configured and / or has at least one opening (41) configured in a center point (M) of the transverse disk (40) and / or a plurality of openings configured on the outer circumference and / or a plurality of openings (44) distributed in the circumferential direction.

6. The screw hub (20) according to any one of the preceding claims, characterized in that At least one web-shaped wall section (35) is formed in the circumferential wall (32), which wall section extends helically in the circumferential direction in the circumferential wall and forms at least a 120° rotation, in particular a 180° rotation or a 360° rotation over the entire length (LN) of the hub section.

7. The screw hub (20) according to claim 6, characterized in that The openings (32) formed in the peripheral wall (31) are arranged helically in the circumferential direction so that, preferably between adjacent openings (32) in the longitudinal direction (R), at least one web-shaped wall section (35) is formed, which extends helically in the circumferential direction and forms at least a 120° rotation, in particular a 180° rotation or a 360° rotation, over the entire length (LN) of the hub section (30).

8. The screw hub (20) according to any of the preceding claims, in particular according to claim 6 or 7, characterized in that A plurality of webs (37) delimiting the opening (32) of the peripheral wall (31), wherein the webs (37), in particular the webs (37) and the at least one web-shaped wall section (35), respectively extend in a longitudinal direction (R) of the screw hub (20) and transversely to the longitudinal direction.

9. The screw hub (20) according to any one of the preceding claims, characterized in that Such a number of openings (32) are formed in the peripheral wall (31) and / or the openings (32) of the peripheral wall (31) have such an opening cross section that the peripheral wall (31) is formed as an open wall structure.

10. The screw hub (20) according to any one of the preceding claims, characterized in that The at least one hub segment (30) is designed as a cast body.

11. The screw hub (20) according to any one of the preceding claims, characterized in that The at least one hub segment (30) is produced by means of a 3D printing method.

12. The screw hub (20) according to any one of the preceding claims, characterized in that A plurality of, in particular two or three or four or five, hub segments (30) which are connected to one another, in particular materially and / or forcefully connected to one another, and which form at least one longitudinal segment (11), preferably the entire longitudinal segment (11) of the screw hub (20).

13. The screw hub (20) according to claim 12, characterized in that The hub segments (30) are connected to one another in such a way that the web-shaped wall segments (35) of the hub segments (30), in particular the web-shaped wall segments (35) according to claim 7, are positioned relative to one another in such a way that a continuously helically extending fastening segment for fastening the screw spiral (60) is formed over the entire longitudinal section (11) of the screw hub (20).

14. A centrifuge screw (10) having a screw hub (20) according to any one of the preceding claims 1 to 13 and at least one screw spiral (60) arranged circumferentially on the screw hub (20).

15. A full-cover screw centrifuge comprising a centrifuge screw (10) according to claim 14 and / or a screw hub (20) according to any one of claims 1 to 13.

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