Drum lid of a solid-wall screw centrifuge

Abstract

Drum lid (30) for discharging clarified medium (56) from a drum (14) of a solid-wall screw centrifuge (10) rotatable about a centrifuge axis (18), with - a first disc-shaped drum lid section (32) in which several outlet openings (38) are located, through which a clarified medium (56) can flow from inside the drum (14) over a weir edge (40) to outside the drum (14), - a second drum cover section (34) which, viewed in the axial direction (20), is located outside the first drum cover section (32) and which is designed to rotatably support the drum (14), and - at least a third drum cover section, via which the first drum cover section (32) is statically connected to the second drum cover section (34), characterized in that the at least one third drum cover section (82; 86; 94) is located radially outside in the radial direction (22) with respect to the weir edge (40).

Description

Background of the invention

[0001] The invention relates to a drum lid for discharging clarified medium from a drum of a solid-jacket screw centrifuge rotatable about a centrifuge axis, comprising a first disc-shaped drum lid section in which several discharge openings are located, through which a clarified medium can flow from inside the drum over a weir edge to outside the drum, as well as a second drum lid section which, viewed axially, is located outside of the first drum lid section and which is designed to rotatably support the drum, and at least a third drum lid section via which the first drum lid section is statically connected to the second drum lid section.

[0002] Solid-wall screw centrifuges, also known as decanters, continuously separate free-flowing mixtures using a drum that rotates at high speed around a centrifugal axis. The mixture is separated within the drum into at least two phases, with a lighter phase, usually a clarified medium, floating on top of a heavier phase, such as particles or sludge, forming what is known as a pond.

[0003] The drum is closed at one of its two axial ends with a drum cover. The drum cover has several sections, which are usually either made from a single piece or bolted or welded together and merge seamlessly. A first drum cover section contains at least one outlet opening through which the clarified medium can flow from inside the drum over a weir edge to the outside. This first drum cover section is generally designed as a disc extending radially from the inside to the outside. A second drum cover section is located, axially speaking, outside the first drum cover section relative to the drum's interior and rotatably supports the drum there. A drum bearing is usually located on or within this second drum cover section.Furthermore, there is at least one third drum lid section, via which the first drum lid section is statically connected to the second drum lid section. This third drum lid section is generally designed as a thickening or a thick-walled hollow cylinder, through the interior of which an inlet pipe for the mixture to be clarified or a drive shaft for a screw extends.

[0004] The outlet opening is normally fitted with a weir plate on the outside of the drum, which has a weir edge facing the outlet opening. This weir edge at the outlet opening determines or regulates the water level or pond depth of the shallow water phase inside the drum.

[0005] From DE 10 2014 108 722 A1, such a solid-jacketed screw centrifuge with a rotor drum for separating a light phase from a solid phase is known. The rotor drum has a disc-shaped end wall which is provided with discharge openings for the light phase. Each discharge opening is associated with a weir which is attached to the end wall.

[0006] From US 2014 0 038 806 A1 a solid shell screw centrifuge is known with a drum and an end-face, disc-shaped drum lid which includes several outlets for a liquid phase. Underlying task

[0007] The invention is based on the objective of creating a drum lid for a solid-wall screw centrifuge for the discharge of clarified medium, in which it is possible to place several discharge openings radially far inwards and thus provide a large pond depth inside the drum. Inventive solution

[0008] This object is achieved according to the invention with a drum lid for discharging clarified medium from a drum of a solid-jacketed screw centrifuge rotatable about a centrifuge axis, comprising a first disc-shaped drum lid section in which several discharge openings are located, through which a clarified medium can flow from inside the drum over a weir edge to outside the drum, and with a second drum lid section which, viewed in the axial direction, is located outside of or in front of the first drum lid section and which is designed to rotatably support the drum, as well as with at least one third drum lid section, via which the first drum lid section is statically connected to the second drum lid section, wherein the at least one third drum lid section is located radially outside with respect to the weir edge when viewed in the radial direction.

[0009] In conventional drum lids, at least one third drum lid section is located radially inward with respect to the at least one weir edge. The weir edge(s) are therefore located radially outward of this third drum lid section. Clarified medium exiting at the respective weir edge can thus be discharged freely radially outward. This free discharge is essential because the drum rotates at high speed, and the exiting medium is therefore subjected to a high centrifugal force and is consequently flung radially outward at the outlet relative to the rotating drum lid.

[0010] In contrast, on the drum lid according to the invention, at least one third drum lid section is located radially outside the weir edge when viewed in the radial direction. This is initially surprising because the drum lid section in this location would actually impede the outflow of clarified medium. However, the invention takes advantage of the fact that the at least one third drum lid section does not necessarily have to extend over the entire circumference of the drum lid, but that free spaces can remain radially outside the weir edges despite the third drum lid section, through which the clarified medium can then flow outwards radially. Thus, the solution according to the invention, with its at least one third drum lid section, creates a supporting effect between the first and second drum lid sections without requiring any space radially inside the weir edge(s).The term "radially outwards when viewed in the radial direction" used here does not mean that the third drum cover section lies on the same radius or radial line outside the weir edge, but only that it is located on a circular ring that is radially further outwards, i.e., has a larger radius, than a circular ring radially further inwards on which the weir edge is located.

[0011] According to the invention, the at least one outlet opening can be positioned radially far inwards or close to the centrifuge axis. The fact that this weakens the rigidity of the drum lid in that location is compensated for by the at least one third drum lid section arranged radially outwards according to the invention.

[0012] In the invention, a comparatively large pond depth can be achieved in the solid-jacket screw centrifuge without excessive weakening of the drum lid due to radially far inwardly positioned outlet openings.

[0013] An advantage of the drum lid according to the invention is that the at least one third drum lid section is positioned and dimensioned such that, at the operating speed of the solid-bowl screw centrifuge, the clarified medium can exit the multiple outlet openings circumferentially and radially outwards without impacting the at least one third drum lid section. The operating speed of solid-bowl screw centrifuges is typically between 600 and 10,000 rpm (six hundred and ten thousand revolutions per minute). As mentioned, this high operating speed causes the clarified medium to be flung outwards from the at least one outlet opening circumferentially and, in particular, radially outwards. This embodiment of the invention ensures that the clarified medium, thus flung outwards, is not obstructed from flowing away.

[0014] Advantageously, the at least one third drum lid section is located, circumferentially, essentially within a circular sector adjacent to the weir edge. A circular sector is a "slice" of a circle. By thus advantageously arranging the third drum lid section, at least substantially, within a circular sector located next to a corresponding or adjacent weir edge, it is particularly possible for the clarified medium to flow freely out of the associated outlet opening in a radial direction during centrifugation. This immediate, unimpeded radial flow is advantageous because the clarified medium does not encounter a rotating component and slow it down, which would result in increased energy consumption of the solid-bowl screw centrifuge.If several weir edges are arranged circumferentially, it is advantageous to have several third drum cover sections located between the circular sectors of the respective weir edges. If the drum cover sections are located circumferentially next to the weir edges, the corresponding weir plates can be easily mounted and dismounted from the radial outside. In particular, the circular sectors of the third drum cover section(s) and the circular sectors of the weir edge(s) can also partially overlap. The respective third drum cover section can then be designed to be comparatively wide, especially circumferentially, and thus correspondingly stable and rigid.

[0015] Furthermore, in the drum cover according to the invention, the number of third drum cover sections is preferably equal to the number of outlet openings. As a rule, the drum cover according to the invention has several outlet openings arranged consecutively and regularly at equal intervals around its circumference. It is also statically advantageous if several third drum cover sections are distributed around the circumference and, in particular, also arranged consecutively and generally at equal intervals. Alternatively, several third drum cover sections can be spaced irregularly or alternately, especially to reduce noise. The number of outlet openings is particularly preferred to be even or odd, between 2 and 10 (in words: two and ten).With an equal number of third drum lid sections and outlet openings, it is possible to provide exactly one third drum lid section at each outlet opening. In this way, not only can a particularly rigid static structure in the form of a grid be created, but unimpeded flow of clarified medium between the respective third drum lid sections is also possible.

[0016] Particularly preferred is the at least one third drum lid section having a substantially triangular cross-section when viewed axially. This triangular cross-section prevents the accumulation of escaping medium on the respective third drum lid section. A substantially triangular cross-section is also advantageous to prevent the outflowing, clarified medium from coming into contact with a component of the drum lid.

[0017] The clarified medium can then always flow easily radially outwards. Furthermore, if a point of the triangular cross-section of the third drum lid section points towards the centrifuge axis, this pointed area of ​​the drum lid section can extend radially almost to the centrifuge axis. In this way, the third drum lid sections can withstand comparatively large forces. Another advantage of this triangular cross-section of the third drum lid section is that there is a relatively large amount of space or clearance radially inside between the respective third drum lid sections, allowing for the placement of an outlet opening and the installation of a corresponding weir plate.

[0018] Alternatively, the at least one third drum lid section is advantageously designed with a substantially polygonal, particularly hexagonal, cross-section when viewed axially. This polygonal cross-sectional shape of the third drum lid section results in a comparatively large cross-sectional area for the third drum lid section, despite its small circumference. With this cross-sectional shape, greater forces can be transmitted for the same surface area. To ensure efficient discharge of the clarified medium when starting or stopping the associated centrifuge, preferably at least one side surface of the third drum lid section is arranged to point in the direction of the centrifuge axis, i.e., largely radially.

[0019] Furthermore, the drum lid according to the invention preferably includes at least a fourth drum lid section, via which the first drum lid section is also statically connected to the second drum lid section. This fourth drum lid section is located radially inside the respective weir edge when viewed in the radial direction. This fourth drum lid section is therefore located on an annular ring between the weir edge and the centrifuge axis when viewed radially. Together with the third drum lid section, it connects the first and second drum lid sections. The first and second drum lid sections are thus connected to each other by means of the third and fourth drum lid sections on an "outer" and an "inner" annular ring, respectively. The drum lid according to the invention is accordingly reinforced or stiffened in this area in a "lattice-like" manner.This stiffening enables the transmission of large forces from the first to the second drum cover section. The fourth drum cover section is particularly preferably formed in cross-section as a ring or a hollow cylinder, and especially integrally with the first and second drum cover sections.

[0020] Preferably, the weir edge is formed on a weir plate which, viewed axially, is attached to the first drum lid section in front of the associated outlet opening. When the weir plate is attached to the first drum lid section, it can create a fluid-tight seal at the associated outlet opening. The clarified medium exiting the outlet opening is thus retained by the weir plate until, when the drum is filled with the medium to be clarified, the desired pond depth or the defined liquid level is reached and the clarified medium flows over the weir edge.

[0021] Alternatively, the weir edge is preferably formed on a channel which, viewed axially, is located downstream of the weir edge on the first drum lid section in the direction of flow of the clarified medium. This channel can deflect the clarified medium exiting through the outlet opening circumferentially, against the direction of rotation of the drum. In this way, the outflow of the clarified medium can be used to assist the rotary drive of the drum of the solid-bowl screw centrifuge. This deflected outflow results in energy recovery from the outflowing, clarified medium. If this channel is positioned radially close to the weir edge, a comparatively large amount of energy can be recovered from the outflowing, clarified medium.

[0022] Advantageously, the weir edge is also formed on a discharge surface that extends axially from the first drum cover section to the second drum cover section. This discharge surface largely "connects" the first drum cover section with the second drum cover section, thus bridging the gap between them. The discharge surface also serves to deflect the outflowing medium circumferentially. Unlike a channel, this discharge surface does not have a channel wall but uses the second drum cover section as a radially oriented boundary surface. This allows for circumferential deflection of the outflowing medium even without a channel shape. This is particularly advantageous with regard to the potential risk of clogging at the discharge surface. Brief description of the drawings

[0023] Exemplary embodiments of the solution according to the invention are explained in more detail below with reference to the accompanying schematic drawings. These show: Fig. 1 a longitudinal section of a solid-wall screw centrifuge according to the prior art along its centrifuge axis, Fig. 2 the right part of the longitudinal section according to Fig. 1 in enlarged view, Fig. 3 the section III - III according to Fig. 2, Fig. 4 the detail IV according to Fig. 2, Fig. 5 the detail V according to Fig. 2, Fig. 6 a part of a longitudinal section of a solid-wall screw centrifuge according to a first embodiment of the invention, Fig. 7 the section VII - VII according to Fig. 6, Fig. 8 a part of a longitudinal section of a solid-wall screw centrifuge according to a second embodiment of the invention, Fig. 9 the section IX - IX according to Fig. 8, Fig. 10 the detail X according to Fig. 8 of a first variant, Fig. 11 the detail XI according to Fig. 6 of a second variant, Fig. 12 the part of a section IX - IX according to Fig. 8 of a third embodiment of the invention, and Fig. 13 the detail XIII according to Fig. 12 in another variant. Detailed description of the exemplary implementations

[0024] Fig. Figure 1 shows a solid-wall screw centrifuge 10 according to the prior art, comprising a housing 12 and a drum 14, which is rotatably mounted, in particular by means of a bearing arrangement 16. The drum 14 can rotate at high speed about a centrifuge axis 18, which defines an axial direction 20 and a radial direction 22. In the axial direction 20, the drum 14 includes a conical drum end 24 in which several discharge openings 26 are distributed around the circumference. Furthermore, the drum 14 is formed from a circular cylindrical drum body 28 and a plate-shaped drum cover 30.

[0025] The drum cover 30 is divided into three drum cover sections: a first, disc-shaped drum cover section 32; a second, hollow cylindrical, thin-walled drum cover section 34; and a third, hollow cylindrical, thick-walled drum cover section 36. The first, disc-shaped drum cover section 32 is connected to the drum body 28. The second, hollow cylindrical, thin-walled drum cover section 34 is located at the bearing assembly 16 and rotatably supported by the bearing assembly 16. The third, also hollow cylindrical but thick-walled drum cover section 36 is located between the first and second drum cover sections 32 and 34 and is integrally connected to them at both of its axial ends.

[0026] Furthermore, in the first, disc-shaped drum cover section 32, there are several outlet openings 38. A weir edge 40 is arranged at each of the outlet openings 38.

[0027] Inside the drum 14, a screw 42 rotates around the centrifuge axis 18 at a comparatively low differential speed. The screw 42 has a hollow cylindrical screw hub 44 and a surrounding screw helix 46. The screw 42 is rotatably mounted on the drum cover 30 by means of a bearing arrangement 48. A medium 52 to be separated or clarified is introduced into the drum 14 through the drum cover 30 and the screw hub 44 via a feed tube 50.

[0028] The medium 52 to be clarified is subjected to a high centrifugal force by rotating the drum around the centrifuge axis 18 and is thus separated into several phases. It separates into a first phase, or separated medium 54, and a second phase, or clarified medium 56. The separated medium 54 settles on the inside of the circular cylindrical drum body 28 of the drum 14 and is conveyed axially by the screw 42 to the conical drum end 24 and then radially inwards along this end and outwards through the discharge openings 26. The usually liquid, clarified medium 56 floats on top of this separated medium 54 and collects as a so-called pond towards the centrifuge axis 18. When a predetermined pond depth or liquid level 58 is reached, the clarified medium 56 flows over the weir edges 40 and is discharged away from the centrifuge axis 18, especially in the radial direction 22 to the outside.

[0029] In Fig. 2 is in detail IV or in Fig. Figure 4 shows such a weir edge 40 on a disc-shaped, radially oriented weir plate 60. Furthermore, detail V or in Fig. 5 represents a weir edge 40 on a trough-shaped channel 62.

[0030] The Fig. Figure 3 shows the drum lid 30 with its direction of rotation 64 and with six outlet openings 38. The outlet openings 38 are spaced apart circumferentially on a ring or circle and extend axially through the drum lid 30. At the outlet openings 38, the liquid level 58 inside the drum 14 reaches the radial height of the weir edges 40 in the axial direction 20 outwards.

[0031] The three outlet openings 38 on the left side and at the top in the Fig. 3 are covered with weir plates 60. The clarified medium 56 flows over these weir plates 60 in three wide discharge streams 66, curved against the direction of rotation.

[0032] At the outlet openings 38 on the right side and at the bottom in the Fig. Three channel channels 62, each with a weir edge 40, are arranged. The clarified medium 56 flows through these channel channels 62, deflected circumferentially, in a comparatively narrow outflow stream 68. The channel channel 62 thus deflects the outflowing medium 56 circumferentially.

[0033] The three weir plates 60 and the three channel channels 62 are screwed to the drum cover 30 by means of fastening screws 70. In the middle of the Fig. 3 is the third drum lid section 36, which can be identified as a thick-walled, hatched ring according to the prior art.

[0034] Fig. Figure 4 shows one of the weir plates 60 as a flat, thin plate whose width completely covers the outlet opening 38 circumferentially and partially extends outwards in the radial direction 22. The weir plate 60, with its weir edge 40, thus determines the liquid level 58 of the clarified medium 56 within the drum 14.

[0035] Fig. Figure 5 shows one of the channel channels 62 with its four sections 72, 74, 76, and 78 and a discharge surface 80. Like the weir plate 60, the channel channel 62 is also attached laterally to the drum cover 30, namely with the first section 72. The second section 74 points axially outwards and acts as a channel bottom. This second section 74 forms a discharge surface 80 and extends essentially in the circumferential direction. The third section 76 points outwards from the second section 74 in the radial direction 22 towards the centrifuge axis 18. The fourth section 78 closes off such a channel channel 62 in the direction of rotation 64.

[0036] The Fig. Figure 6 shows a part of the solid-bowl screw centrifuge 10 according to a first embodiment with the drum lid 30. The drum lid 30 is as shown in Fig. 1 divided into the first drum lid section 32, the second drum lid section 34, a third drum lid section 82 according to the invention and additionally a fourth drum lid section 84 according to the invention.

[0037] In the first drum lid section 32, outlet openings 38 are formed which extend obliquely inwards towards the centrifuge axis 18 and are designed to widen outwards.

[0038] The third and fourth drum cover sections 82, 84 are arranged between the first and second drum cover sections 32, 34. The third drum cover section 82 extends near the first drum cover section 32, within a first region 86 which has an annular cross-section, and near the second drum cover section 34, within a disc-shaped second region 88.

[0039] The first section 86 adjoins the first drum lid section 32 and is located radially outside the associated weir edges 40. The first section 86 is interrupted by several outflow openings 90, from which the clarified medium 56 can flow radially outwards through the drum lid 30.

[0040] The second section 88 is plate-shaped and arranged axially adjacent to the weir edges 40 and, with respect to the radial direction 22, both outside and inside them. It connects the first section 86 with the second drum cover section 34. Mounting holes 92 are provided axially adjacent to the fastening screws 70 in the second section 88, through which these fastening screws 70 can be mounted in the axial direction 20. Alternatively, the second section 88 can also be designed not as a plate, but in a star or grid shape using spokes or struts to connect the first section 86 with the second drum cover section 34.

[0041] The fourth, relatively thin-walled, tubular drum lid section 84 connects the first drum lid section 32 to the second section 88 in the radial direction 22, starting from the outlet openings 38. The fourth drum lid section 84 can alternatively be polygonal. The fourth drum lid section 84 thus provides additional radial stiffening to the drum lid 30 far inwards. It also serves to prevent outflowing, clarified medium 56 from flowing inwards in the radial direction 22.

[0042] As in Fig. As can be seen in Figure 7, six outlet openings 38 are provided. Three of these outlet openings 38, which are located in Fig. 7 on the left side and above, weir plates 60 with associated outflow streams 66 are shown. At the three remaining outlet openings 38, which are located in Fig. 7 on the right side and below, channel channels 62 with the respective outflow streams 68 are shown.

[0043] In the radial direction 22 outside the outlet openings 38 are in Fig. Figure 7 shows the first section 86 of the third drum lid section 82 according to the invention in cross-section, and the fourth, annular drum lid section 84 is visible in the radial direction 22 within the outlet openings 38. The annular shape of the first section 86 is subdivided circumferentially by the outlet openings 90 into several elements 94. In the cross-section shown, these elements 94 each have a substantially triangular shape, with one corner pointing towards the centrifuge axis 18. This corner is rounded, while the other two corners of the triangular shape are sharp-edged. The rounding of the radially inward-pointing corner has the advantage that the clarified medium 56 can flow outwards with minimal turbulence.

[0044] The elements 94 of the first area 86 are located in a circular sector in the circumferential direction essentially next to an adjacent weir edge 40. The number of elements 94 is equal to the number of weir edges 40 or outlet openings 38.

[0045] The clarified medium 56 flows through the outlet opening 38 over the associated weir edge 40. At the three weir plates 60, each with the wide outflow stream 66, the clarified medium 56 flows directly radially outwards through the outlet opening 90 located between two adjacent elements 94. At the three channel channels 62, however, due to the deflection in the direction of rotation, the clarified medium 56 flows through an outlet opening 90 adjacent in the circumferential direction. The clarified medium 56 thus "skips" one of the elements 94.

[0046] The Fig. 8 and Fig. Figure 9 shows a part of a solid-bowl screw centrifuge 10 according to a second embodiment of the invention. As in the first embodiment according to Fig. In Figure 6, the drum cover 30 is divided into a first and second drum cover section 32 and 34 respectively, and a third drum cover section 82 according to the invention. A fourth drum cover section 84 does not exist in this embodiment.

[0047] In the first drum lid section 32 according to Fig. 8 and Fig. 9 is compared to Fig. 6. The outlet opening 38 with its weir edge 40 is positioned even closer to the centrifuge axis 18. This allows the liquid level 58 in the drum 14 to slide closer to the centrifuge axis 18, or the pond depth to be greater, than in the first embodiment according to [reference]. Fig. 6.

[0048] The third drum lid section 82 of this embodiment also comprises an annular, interrupted area 86 on the first drum lid section 32 and a disc-shaped area 88 on the second drum lid section 34. The area 86 is arranged closer to the centrifuge axis 18 in the radial direction 22. The disc of the area 88 is correspondingly smaller in diameter.

[0049] As in Fig. As can be seen in Figure 9, six outlet openings 38 with three weir plates 60 with outflow streams 66 are shown at the top left, as well as three channel channels 62 with outflow streams 68 at the bottom right. In contrast to Fig. 3 and Fig. 7 the weir plates 60 and the channel channels 62 are screwed to the outside of the outlet openings 38 by means of fastening screws 70 in radial direction 22.

[0050] According to the invention, here as in Fig. 7 in radial direction 22 outside the outlet openings 38, the first region 86 is formed. The first region 86 is also subdivided into several elements 94, which are arranged circumferentially on a concentric ring around the centrifuge axis 18. The elements 94 lie essentially on circular sectors next to an adjacent weir edge 40, and the number of elements 94 is equal to the number of outlet openings 38.

[0051] The elements 94 according to Fig. Nine of these have a hexagonal shape in cross-section. Two of the faces of this hexagon point towards the centrifuge axis 18. The hexagonal shape, as shown in the section, has Fig. As can be clearly seen in 9, it has a larger cross-sectional area than that shown in Fig. The triangular shape shown in Figure 7. Additionally, as mentioned, the first region 86 is positioned further radially inwards in this embodiment. These two circumstances allow higher forces to be transmitted with this region 86 than in the embodiment shown in Figure 7. Fig. 6 and Fig. 7. Especially under torsional stress, this geometric shape of the elements 94 according to Fig. 9 and their arrangement is particularly advantageous.

[0052] Fig. Figure 10 shows a channel 62 for the drum lid section 82 according to the invention. In contrast to the embodiment according to Fig. In Figure 5, this channel 62 has only three sections 72, 74, and 78. The third section 76 is replaced here by the inner wall of the second section 88 of the third drum cover section 82, which faces the outlet opening 38. The first three sections 72, 74, and 78 are largely identical to those in the embodiment according to Figure 5. Fig. 5.

[0053] The difference in this channel 62 lies in the fact that the second and fourth sections 74, 78 extend with the outflow surface 80 in axial direction 20 from the outlet opening 38 to the second section 88 of the third drum cover section 82. The second section 88 thus assumes the function of deflecting the exiting, clarified medium in the circumferential direction.

[0054] Fig. Figure 11, in comparison, shows the installation situation with a classic or conventional weir plate 60 in the drum cover 30 according to the invention.

[0055] In Fig. Figure 12 shows that in this alternative embodiment, element 94 has a substantially pentagonal cross-section. In this embodiment, element 94 is adapted to the direction of rotation 64 and is designed to be dependent on the direction of rotation. The design of element 94 is oriented towards the outer edges of the paths of the outflow streams 66 and 68 that face element 94. Element 94 fills precisely the space in which the outflow streams 66 and 68 cannot be located. This results in both outflow streams 66 and 68 being discharged with particularly little resistance and turbulence. To illustrate this, the following are shown in Fig. 12 also both outflow streams 66 and 68 are shown at a single outlet opening 38.

[0056] The rotation-direction-dependent, pentagonal shape, as seen in section according to Fig. Figure 12 shows a larger cross-sectional area than the one shown in Fig. 7 depicted triangular shape as well as the one in Fig. The hexagonal shape shown in Figure 9 allows for the transmission of higher forces due to its larger cross-sectional area compared to the embodiments shown in Figure 9. Fig. 6, Fig. 7, Fig. 8 to Fig. 9. Especially under torsional stress, this essentially pentagonal shape of the elements 94 according to Fig. 12 and their arrangement is particularly advantageous.

[0057] Fig. Figure 13 shows a further embodiment of element 94 according to Fig. 12. In this embodiment, the corners of the essentially pentagonal cross-section, which point towards the centrifuge axis 18, are rounded. Rounding the corners of element 94 allows it to be adapted even more closely to the arc shape of the outflow streams 66 and 68. The cross-sectional area of ​​element 94 according to Fig. 13 is thus compared to element 94 according to Fig.Enlarged 12 times further.

[0058] Finally, it should be noted that all features mentioned in the application documents and in particular in the dependent claims shall, despite the formal reference made to one or more specific claims, be afforded independent protection, whether individually or in any combination. Reference symbol list 10 solid jacket screw centrifuges 12 cases 14 Drum 16 Storage arrangement 18 Centrifuge axis 20 Axial direction 22 Radial direction 24 Drum finish 26 Ejection opening 28 drum bodies 30 drum lids 32 first drum lid section 34 second drum lid section 36 third drum lid section 38 Outlet opening 40 Wehrkante 42 Snail 44 snail hub 46 snail spirals 48 Storage arrangement 50 feed pipe 52 medium to be clarified 54 isolated medium 56 clarified medium 58 Fluid level 60 Wehrplatte 62 Channel 64 Direction of rotation 66 Outflow 68 Outflow 70 fastening screws Area 72 Area 74 76 area Area 78 80 discharge area 82 third drum lid section 84 fourth drum lid section 86 first area 88 second area 90 Outlet opening 92 Mounting holes 94 Element

Claims

[1] Drum lid (30) for discharging clarified medium (56) from a drum (14) rotatable about a centrifuge axis (18) of a solid-wall screw centrifuge (10), with - a first disc-shaped drum lid section (32) in which several outlet openings (38) are located, through which a clarified medium (56) can flow from inside the drum (14) over a weir edge (40) to outside the drum (14), - a second drum cover section (34) which, viewed in the axial direction (20), is located outside the first drum cover section (32) and which is designed to rotatably support the drum (14), and - at least a third drum cover section, via which the first drum cover section (32) is statically connected to the second drum cover section (34), characterized by, that the at least one third drum lid section (82; 86; 94) is located radially outside in the radial direction (22) with respect to the weir edge (40). [2] Drum lid according to claim 1, characterized by , that the at least one third drum lid section (82; 86; 94) is positioned and dimensioned such that, at operating speed of the solid-jacket screw centrifuge (10), the clarified medium (56) exits from the multiple outlet openings (38) in a circumferential direction and radially outwards without impacting the at least one third drum lid section (82; 86; 94). [3] Drum lid according to claim 1 or 2, characterized by , that the at least one third drum lid section (82; 86; 94) is located next to the weir edge (40) when viewed in the circumferential direction. [4] Drum lid according to any one of claims 1 to 3, characterized by, that the number of third drum cover sections (82, 86; 94) is equal to the number of outlet openings (38). [5] Drum lid according to any one of claims 1 to 4, characterized by , that the at least one third drum lid section (82; 86; 94) is considered in the axial direction (20) and is essentially triangular in cross-section. [6] Drum lid according to any one of claims 1 to 4, characterized by , that the at least one third drum lid section (82; 86; 94) is considered in the axial direction (20) and is essentially hexagonal in cross-section. [7] Drum lid according to any one of claims 1 to 6, characterized by, that at least a fourth drum cover section (84) is provided, via which the first drum cover section (32) is also statically connected to the second drum cover section (34), wherein the at least one fourth drum cover section (84) is located radially inside in the radial direction (22) with respect to the respective weir edge (40). [8] Drum lid according to any one of claims 1 to 7, characterized by , that the weir edge (40) is formed on a weir plate (60) which, viewed in the axial direction (20), is attached in front of the associated outlet opening (38) on the first drum cover section (32). [9] Drum lid according to any one of claims 1 to 7, characterized by , that the weir edge (40) is formed on a channel trough (62) which, viewed in the axial direction (20), is attached in front of the associated outlet opening (38) on the first drum cover section (32). [10] Drum lid according to any one of claims 1 to 6, characterized by, that the weir edge (40) is formed on a discharge surface (80) which, viewed in the axial direction (20), extends from the first drum cover section (32) to the third drum cover section (82).

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