SEPARATING DEVICE AND TURBOMACHINE COMPRISING SEPARATING DEVICE
20230009371 · 2023-01-12
Inventors
- Johannes Walter (Durbach, DE)
- Ansgar Harnischmacher (Kappelrodeck, DE)
- Hannes Butscher (Sinzheim, DE)
- Matthias Kruse (Buehlertal, DE)
Cpc classification
F04D29/426
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F04D29/167
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F04D29/685
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F04D29/16
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F04D29/42
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F04D29/68
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
The invention relates to a separating device for a turbomachine, comprising at least one housing (12) that has at least one bearing receiving area (24), which defines at least one bearing axis (26), and at least one wheel-side area (28). The separating device also comprises at least one swirling unit (32), which is arranged on the housing (12) in particular, for deflecting and/or swirling at least one fluid and/or particle flow (34), wherein the swirling unit (32) has at least one flow recess (38) which is delimited by a wall (36) of the housing (12) and which extends within the wheel-side area (28) at a distance from the bearing axis (26). According to the invention, the swirling unit (32) comprises at least one seal gap element (40) which is arranged on a wall (36) of the housing (12) and which is designed to deflect and/or swirl at least one fluid and/or particle flow (34) flowing through the flow recess (38) along the bearing axis (26) and/or towards the bearing axis (26).
Claims
1. A separating device for a turbomachine, the separating device having at least one housing (12) which has at least one bearing receptacle (24) defining at least one bearing axis (26) and which has at least one impeller side chamber (28), and the separating device having at least one swirling unit (32) for diverting and/or swirling at least one fluid and/or particle flow (34), wherein the swirling unit (32) has at least one flow recess (38), which is delimited by a wall (36) of the housing (12) and which extends within the impeller side chamber (28) so as to be spaced apart from the bearing axis (26), characterized in that the swirling unit (32) comprises at least one sealing gap element (40) which is arranged on a wall (36) of the housing (12) and which is configured for diverting and/or swirling at least one fluid and/or particle flow (34) flowing through the flow recess (38) along the bearing axis (26) and/or toward the bearing axis (26).
2. The separating device as claimed in claim 1, characterized in that the sealing gap element (40) at least partially delimits the flow recess (38).
3. The separating device as claimed in claim 1, characterized in that the swirling unit (32) comprises at least one further sealing gap element (88) which is arranged on a wall (36) of the housing (12) and which at least partially delimits the flow recess (38).
4. The separating device as claimed in claim 1, characterized in that the swirling unit (32) comprises at least one further sealing gap element (88) which, as viewed at least substantially perpendicularly with respect to the bearing axis (26), has a minimum radial spacing (110) to the bearing axis (26) which is greater than a minimum radial spacing (112) of the sealing gap element (40) and of the bearing axis (26), wherein the flow recess (38) is, as viewed from the bearing axis (26), arranged between the sealing gap element (40) and the further sealing gap element (88).
5. The separating device as claimed in claim 1, characterized in that the swirling unit (32) comprises at least one further sealing gap element (88), wherein at least two outer surfaces (92, 94, 96), which adjoin one another and which form a sealing edge (114), of the further sealing gap element (88) span an angle (118) of less than 90° as viewed at least substantially perpendicularly with respect to the bearing axis (26).
6. The separating device as claimed in claim 1, characterized in that the swirling unit (32) comprises at least one further sealing gap element (88) which has a sealing edge (114) arranged such that at least one of two outer surfaces (92, 96), which form a sealing edge (114), of the further sealing gap element (88) is oriented at least substantially parallel to the bearing axis (26).
7. A turbomachine, comprising at least one drive unit (14) which has at least one drive axis (16), at least one conveying unit (18) which is driven around the drive axis (16), which serves for conveying a fluid and which has at least one conveying element (22), and at least one separating device (20) having at least one housing (12) which has at least one bearing receptacle (24) defining at least one bearing axis (26) and which has at least one impeller side chamber (28), and the separating device having at least one swirling unit (32) for diverting and/or swirling at least one fluid and/or particle flow (34), wherein the swirling unit (32) has at least one flow recess (38), which is delimited by a wall (36) of the housing (12) and which extends within the impeller side chamber (28) so as to be spaced apart from the bearing axis (26), characterized in that the swirling unit (32) comprises at least one sealing gap element (40) which is arranged on a wall (36) of the housing (12) and which is configured for diverting and/or swirling at least one fluid and/or particle flow (34) flowing through the flow recess (38) along the bearing axis (26) and/or toward the bearing axis (26), wherein the conveying unit (18) is arranged at least predominantly within the impeller side chamber (28) around the drive axis (16).
8. The turbomachine as claimed in claim 7, characterized in that a maximum spacing (120), oriented at least substantially parallel to the drive axis (16), between the sealing gap element (40) and the conveying element (22) is less than 2 mm.
9. The turbomachine as claimed in claim 7, characterized in that the swirling unit (32) has at least one further sealing gap element (88) which, as viewed at least substantially perpendicularly with respect to the drive axis (16), is arranged at least partially within a maximum longitudinal extent (102) of the conveying element (22).
10. The turbomachine as claimed in claim 9, characterized in that a maximum spacing (124), oriented at least substantially perpendicular to the drive axis (16), between the further sealing gap element (88) and the conveying element (22) is less than 2 mm.
11. The turbomachine as claimed in claim 7, characterized in that the conveying element (22) has at least one bevel and/or at least one rounded portion (134) in an edge region on at least a side facing toward the sealing gap element (40) and/or the flow recess (38).
12. The turbomachine as claimed in claim 7, characterized in that the sealing gap element (40) has a minimum radial spacing (112) to the drive axis (16) which corresponds to at most 90% of a maximum radial extent (142) of the conveying element (22) around the drive axis (16).
13. The separating device as claimed in claim 1, wherein the swirling unit (32) is arranged on the housing (12).
14. A coolant pump comprising at least one drive unit (14) which has at least one drive axis (16), at least one conveying unit (18), which is an impeller disk, which is driven around the drive axis (16), which serves for conveying a coolant, and which has at least one conveying element (22), wherein the conveying element is a vane, and at least one separating device (20) having at least one housing (12) which has at least one bearing receptacle (24) defining at least one bearing axis (26) and which has at least one impeller side chamber (28), and the separating device having at least one swirling unit (32) for diverting and/or swirling at least one fluid and/or particle flow (34), wherein the swirling unit (32) has at least one flow recess (38), which is delimited by a wall (36) of the housing (12) and which extends within the impeller side chamber (28) so as to be spaced apart from the bearing axis (26), characterized in that the swirling unit (32) comprises at least one sealing gap element (40) which is arranged on a wall (36) of the housing (12) and which is configured for diverting and/or swirling at least one fluid and/or particle flow (34) flowing through the flow recess (38) along the bearing axis (26) and/or toward the bearing axis (26), wherein the conveying unit (18) is arranged at least predominantly within the impeller side chamber (28) around the drive axis (16).
15. The turbomachine as claimed in claim 14, characterized in that a maximum spacing (120), oriented at least substantially parallel to the drive axis (16), between the sealing gap element (40) and the conveying element (22) is less than 2 mm.
16. The turbomachine as claimed in claim 15, characterized in that the swirling unit (32) has at least one further sealing gap element (88) which, as viewed at least substantially perpendicularly with respect to the drive axis (16), is arranged at least partially within a maximum longitudinal extent (102) of the conveying element (22).
17. The turbomachine as claimed in claim 16, characterized in that a maximum spacing (124), oriented at least substantially perpendicular to the drive axis (16), between the further sealing gap element (88) and the conveying element (22) is less than 2 mm.
18. The turbomachine as claimed in claim 17, characterized in that the conveying element (22) has at least one bevel and/or at least one rounded portion (134) in an edge region on at least a side facing toward the sealing gap element (40) and/or the flow recess (38).
19. The turbomachine as claimed in claim 18, characterized in that the sealing gap element (40) has a minimum radial spacing (112) to the drive axis (16) which corresponds to at most 90% of a maximum radial extent (142) of the conveying element (22) around the drive axis (16).
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Further advantages will emerge from the following description of the drawings. The drawings illustrate an exemplary embodiment of the invention. The drawings, the description and the claims contain numerous features in combination. A person skilled in the art will expediently also consider the features individually and combine them to form meaningful further combinations.
[0023] In the drawings:
[0024]
[0025]
[0026]
[0027]
DETAILED DESCRIPTION
[0028]
[0029] The conveying elements 22 delimit in each case one conveying channel 42 for conveying the fluid. The conveying channel 42 extends within the conveying element 22 from a conveying inlet 44 of the conveying channel 42, arranged at least substantially parallel to the drive axis 16, to a conveying outlet 46 of the conveying channel 42, oriented at least substantially perpendicular to the drive axis 16. The conveying unit 18, in particular the conveying element 22, is preferably provided for directing a fluid and/or particle flow 34, which has been diverted and/or swirled by the flow recess 38 and the sealing gap element 40, along a wall 48 of the conveying unit 18, in particular of the conveying element 22, in the direction 50 pointing away from the drive axis 16, preferably by way of a centrifugal force resulting from a rotation of the conveying element 22 about the drive axis 16. It is conceivable for the conveying unit 18, in particular the conveying elements 22, to comprise, on a side facing toward the flow recess 38, at least one fluid-directing element 52 which is provided for directing a fluid and/or particle flow 34, which has been directed onto the wall 48 of the conveying unit 18, in a direction 50 pointing away from the drive axis 16. For example, the fluid-directing element 52 is configured as a molded part, as a flow element, as a surface structure, as a fin and/or as some other fluid-directing element 52 that appears expedient to a person skilled in the art for diverting a fluid and/or particle flow 34.
[0030] The sealing gap element 40 is configured as a molded part configured as a sealing collar. The sealing gap element 40 is formed as a single piece with the housing 12. The sealing gap element 40 is of circular-ring-shaped configuration as viewed along the bearing axis 26. The sealing gap element 40 is at least predominantly of hollow cylindrical configuration. The sealing gap element 40 has an at least approximately rectangular cross-sectional area 54 in a plane in which the bearing axis 26 is arranged. The sealing gap element 40 is arranged uniformly around the bearing axis 26, wherein, in particular, the cross-sectional area 54 of the sealing gap element 40 is configured to be at least substantially constant along a circumferential direction 56 around the bearing axis 26. The sealing gap element 40 has a central axis 58, wherein the sealing gap element 40 is in particular configured so as to be symmetrical around the central axis 58. The sealing gap element 40 is arranged such that the central axis 58 of the sealing gap element 40 is arranged within the bearing axis 26. The sealing gap element 40 has an inner surface 60 and an outer surface 62 which are in particular at least partially arranged at least substantially parallel to one another. Preferably, the inner surface 60 and the outer surface 62 of the sealing gap element 40 are in particular at least partially arranged at least substantially parallel to the bearing axis 26. The outer surface 62 of the sealing gap element 40 is arranged at least predominantly on a side of the sealing gap element 40 which is averted from the bearing axis 26. The inner surface 60 of the sealing gap element 40 is arranged at least predominantly on a side of the sealing gap element 40 which faces toward the bearing axis 26. The sealing gap element 40 has a sealing gap surface 64 which is in particular arranged at least substantially perpendicular to the bearing axis 26. The sealing gap surface 64 is particularly preferably configured as a circular ring. In particular, the sealing gap surface 64 is delimited by the inner surface 60 and/or the outer surface 62 of the sealing gap element 40. Other configurations of the sealing gap element 40 are however also conceivable, for example in the form of a sealing ring and/or with a shape that differs from a hollow cylinder, in particular with a different arrangement on the housing 12.
[0031] The housing 12, in particular that wall 36 of the housing 12 which delimits the flow recess 38, is configured such that the flow recess 38 is of streamlined configuration as viewed at least substantially perpendicularly with respect to the bearing axis 26. That wall 36 of the housing 12 which delimits the flow recess 38 has, as viewed at least substantially perpendicularly with respect to the bearing axis 26, a contour 66 which is of rounded, in particular at least partially elliptical, configuration. In particular, the contour 66 of that wall 36 of the housing 12 which delimits the flow recess 38 is configured without corners. The flow recess 38 is arranged in an edge region 68 of the impeller side chamber 28 which is spaced apart from the bearing axis 26. The flow recess 38 is fluidically connected to the impeller side chamber 28. The flow recess 38 extends at least substantially all the way around the bearing axis 26. The flow recess 38 has, as viewed along the circumferential direction 56 around the bearing axis 26, a cross-sectional area 70 which, along the circumferential direction 56, has a maximum deviation of at most 5%, preferably at most 3% and particularly preferably at most 1%, of an average value of the cross-sectional area 70 of the flow recess 38. The housing 12 has a spiral chamber 72 which is fluidically connected to the impeller side chamber 28 and to the flow recess 38. The spiral chamber 72 extends at least substantially all the way around the bearing axis 26. The spiral chamber 72 is at least partially of helical configuration as viewed along the bearing axis 26. The spiral chamber 72 adjoins the edge region 68 of the impeller side chamber 28 and/or adjoins the flow recess 38. The spiral chamber 72 comprises at least one outlet opening 74 for the discharge of the fluid that is to be moved (cf.
[0032] In particular, a fluid and/or particle flow 34 that is moved by means of the conveying unit 18 flows at least partially along the wall 36 of the housing 12 from the spiral chamber 72 into the impeller side chamber 28 and the flow recess 38 in the direction of the bearing axis 26. The fluid and/or particle flow 34 is shown in the figures with an exemplary course of the flow in each case. The separating device 20 is preferably provided for preventing the fluid and/or particle flow 34 from flowing from the impeller side chamber 28 in the direction of the bearing axis 26. In particular, the fluid and/or particle flow 34 is implemented within a fluid that is to be moved by means of the turbomachine 10. For example, the fluid and/or particle flow 34 takes the form of contamination and/or residues within the fluid that is to be moved. The swirling unit 32 is preferably provided for diverting the fluid and/or particle flow 34 flowing through the flow recess 38 along the bearing axis 26, and/or toward the bearing axis 26, into a direction 82 which points away from the wall 36 of the housing 12 and/or which is oriented at least substantially parallel to the bearing axis 26 and/or to a longitudinal extent of the sealing gap element 40.
[0033] The sealing gap element 40 at least partially delimits the flow recess 38. The sealing gap element 40 is arranged on that wall 36 of the housing 12 which delimits the flow recess 38. As viewed at least substantially perpendicularly with respect to the bearing axis 26, the outer surface 62 of the sealing gap element 40 is formed in a connecting region 86 of the sealing gap element 40 and that wall 36 of the housing 12 which delimits the flow recess 38 and, preferably flush, in a plane with that wall 36 of the housing 12 which delimits the flow recess 38. The outer surface 62 of the sealing gap element 40 is rounded, in particular oriented transversely with respect to the bearing axis 26, in the connecting region 86 of the sealing gap element 40 and that wall 36 of the housing 12 which delimits the flow recess 38.
[0034] The swirling unit 32 comprises a further sealing gap element 88 which is arranged on the wall 36 of the housing 12 and which at least partially delimits the flow recess 38. The further sealing gap element 88 is configured as a molded part. Other embodiments of the further sealing gap element 88 are however also conceivable. The further sealing gap element 88 is formed as a single piece with the housing 12. The further sealing gap element 88 is of circular-ring-shaped configuration as viewed along the bearing axis 26. The further sealing gap element 88 is of at least partially hollow cylindrical configuration. The further sealing gap element 88 has a central axis 90, wherein, in particular, the further sealing gap element 88 is arranged such that the central axis 90 of the further sealing gap element 88 is arranged within the bearing axis 26. The further sealing gap element 88 has an inner surface 92 and an outer surface 94 which are at least partially arranged at least substantially parallel to one another. The inner surface 92 and the outer surface 94 of the further sealing gap element 88 are at least partially arranged at least substantially parallel to the bearing axis 26. The further sealing gap element 88 has a side surface 96 which is arranged in particular transversely, preferably at least partially at least substantially perpendicularly, with respect to the bearing axis 26. The side surface 96 of the further sealing gap element 88 is delimited by the inner surface 92 and the outer surface 94 of the further sealing gap element 88. The further sealing gap element 88 is arranged on that wall 36 of the housing 12 which delimits the flow recess 38. The outer surface 94 of the further sealing gap element 88 is arranged at least predominantly on a side of the further sealing gap element 88 which is averted from the bearing axis 26. The inner surface 92 of the further sealing gap element 88 is arranged at least predominantly on a side of the further sealing gap element 88 which faces toward the bearing axis 26. In particular, as viewed at least substantially perpendicularly with respect to the bearing axis 26, the inner surface 92 of the further sealing gap element 88 is formed in a connecting region 98 of the further sealing gap element 88 and that wall 36 of the housing 12 which delimits the flow recess 38 and, preferably flush, in a plane with that wall 36 of the housing 12 which delimits the flow recess 38. The inner surface 92 of the sealing gap element 40 is preferably rounded, in particular oriented transversely with respect to the bearing axis 26, in the connecting region 98 of the further sealing gap element 88 and that wall 36 of the housing 12 which delimits the flow recess 38. The further sealing gap element 88 is configured and/or arranged such that the further sealing gap element 88, in particular the outer surface 94 of the further sealing gap element 88, at least partially delimits the spiral chamber 72. The further sealing gap element 88 is arranged between the impeller side chamber 28 and the spiral chamber 72. The further sealing gap element 88, in particular the side surface 96 of the further sealing gap element 88, at least partially delimits the fluid opening 76.
[0035]
[0036] As viewed at least substantially perpendicularly with respect to the bearing axis 26, the further sealing gap element 88 has a minimum radial spacing 110 to the bearing axis 26 which is greater than a minimum radial spacing 112 of the sealing gap element 40 and of the bearing axis 26, wherein the flow recess 38 is, as viewed from the bearing axis 26, arranged between the sealing gap element 40 and the further sealing gap element 88. The minimum radial spacings 110, 112 of the sealing gap element 40 and of the further sealing gap element 88 to the bearing axis 26 extend at least substantially perpendicular to the bearing axis 26. The minimum radial spacing 112 of the sealing gap element 40 extends from the inner surface 60 of the sealing gap element 40 to the bearing axis 26. The minimum radial spacing 110 of the further sealing gap element 88 extends from the inner surface 92 of the further sealing gap element 88 to the bearing axis 26. The minimum radial spacing 112 of the sealing gap element 40 is at least 40%, preferably at least 50% and particularly preferably at least 60% of the minimum radial spacing 110 of the further sealing gap element 88. The flow recess 38 is spanned within the impeller side chamber 28 by the sealing gap element 40 and the further sealing gap element 88 together with that wall 36 of the housing 12 which delimits the flow recess 38.
[0037] Two outer surfaces 92, 94, 96 of the further sealing gap element 88 which adjoin one another and which form a sealing edge 114 of the further sealing gap element 88, in particular the inner surface 92, the outer surface 94 and/or the side surface 96, span at least an angle 118 of less than 90°, preferably of less than 80° and particularly preferably of less than 70°, as viewed at least substantially perpendicularly with respect to the bearing axis 26, in particular in a vicinity of the sealing edge 114 of the further sealing gap element 88. The angle 118 that is spanned by the side surface 96 of the further sealing gap element 88 and the outer surface 94 or the inner surface 92 of the further sealing gap element 88, in particular in the vicinity of the sealing edge 114 of the further sealing gap element 88, is in particular less than 90°, preferably less than 80° and particularly preferably less than 70°. The sealing edge 114 of the further sealing gap element 88 is arranged at least substantially perpendicular to the bearing axis 26 and at least substantially all the way around the bearing axis 26. The sealing edge 114 of the further sealing gap element 88 is arranged such that at least one of two outer surfaces 92, 94, 96 of the further sealing gap element 88 which form the sealing edge 114 of the further sealing gap element 88, in particular the inner surface 92, is oriented at least substantially parallel to the bearing axis 26.
[0038] A maximum spacing 120, oriented at least substantially parallel to the drive axis 16, between the sealing gap element 40 and the conveying element 22 is in particular less than 2 mm, preferably less than 1.5 mm and particularly preferably less than 1 mm. It is preferable if the maximum spacing 120, oriented at least substantially parallel to the drive axis 16, between the sealing gap element 40 and the conveying element 22 extends from the sealing gap surface 64 of the sealing gap element 40 to the conveying element 22, in particular to at least one surface 122 of the conveying element 22 which is oriented at least substantially perpendicular to the drive axis 16. The sealing gap element 40 and the conveying element 22 are arranged such that a sealing gap is formed between the sealing gap element 40 and the conveying element 22, in particular by the maximum spacing 120. A maximum spacing 124, oriented at least substantially perpendicular to the drive axis 16, between the further sealing gap element 88 and the conveying element 22 is in particular less than 2 mm, preferably less than 1.5 mm and particularly preferably less than 1 mm. The maximum spacing 124, oriented at least substantially perpendicularly with respect to the drive axis 16, between the further sealing gap element 88 and the conveying element 22 preferably extends from the inner surface 92 of the further sealing gap element 88 to a side surface 126 of the conveying element 22 that borders the conveying outlet 46, wherein, in particular, the side surface 126 of the conveying element 22 is at least partially oriented at least substantially parallel to the drive axis 16. The further sealing gap element 88 and the conveying element 22 are arranged such that a further sealing gap is formed between the further sealing gap element 88 and the conveying element 22, in particular by the maximum spacing 124.
[0039] As viewed at least substantially perpendicularly with respect to the drive axis 16, the further sealing gap element 88 is arranged at least partially within a maximum longitudinal extent 128 of the conveying element 22. The maximum longitudinal extent 128 of the conveying element 22 is oriented at least substantially parallel to the drive axis 16. The further sealing gap element 88 is arranged, as viewed at least substantially perpendicularly with respect to the drive axis 16, outside a maximum longitudinal extent 130 of the conveying outlet 46 of the conveying channel 42, which is in particular oriented at least substantially parallel to the drive axis 16. The maximum longitudinal extent 130 of the conveying outlet 46 of the conveying channel 42 corresponds at least substantially to the opening width 78 of the fluid opening 76, which is in particular at least partially delimited by the further sealing gap element 88. In particular, the conveying element 22 is arranged relative to the separating device 20 such that the conveying outlet 46 and the fluid opening 76 are, as viewed in at least one section plane of the turbomachine 10 through the drive axis 16, arranged congruently one behind the other proceeding from the drive axis 16. As viewed in particular in at least one section plane of the turbomachine 10 through the drive axis 16, the side surface 96 of the further sealing gap element 88 is arranged at least partially in a plane with an inner surface 132, which delimits the conveying outlet 46, of the conveying element 22. The inner surface 132, which delimits the conveying outlet 46, of the conveying element 22 is oriented at least substantially perpendicular to the drive axis 16. The inner surface 132, which delimits the conveying outlet 46, of the conveying element 22 is arranged so as to be averted from the flow recess 38.
[0040] The conveying element 22 has a rounded portion 134 in an edge region on a side facing toward the sealing gap element 40 and/or the flow recess 38. It is alternatively or additionally conceivable for the conveying element 22 to have a bevel in the edge region on the side facing toward the sealing gap element 40 and/or the flow recess 38. The rounded portion 134 extends at least partially along the circumferential direction 56 around the drive axis 16. The rounded portion 134 is preferably arranged on the side surface 126 of the conveying element 22. The conveying element 22 has at least one sealing edge 136 which is in particular delimited by the side surface 126 and by the inner surface 132, which delimits the conveying outlet 46, of the conveying element 22. The sealing edge 136 of the conveying element 22 is at least partially configured so as to run at least substantially perpendicular to the drive axis 16 and along the circumferential direction 56 around the drive axis 16. The side surface 126 and the inner surface 132, which delimits the conveying outlet 46, of the conveying element 22 at least partially, in particular in a vicinity around the sealing edge 136 of the conveying element 22, have an angle 138 of in particular at most 90°, preferably at most 80° and particularly preferably at most 70°.
[0041] The sealing gap element 40 has the minimum spacing 112 to the drive axis 16 which corresponds to at most 90%, in particular at most 80%, preferably at most 70% and particularly preferably at most 60%, of a maximum radial extent 142 of the conveying element 22 around the drive axis 16. Preferably, the minimum spacing 112 of the sealing gap element 40 to the drive axis 16 corresponds in particular to at least 30%, preferably at least 40% and particularly preferably at least 50%, of the maximum radial extent 142 of the conveying element 22 around the drive axis 16. In particular, the minimum spacing 112 of the sealing gap element 40 to the drive axis 16 extends at least substantially perpendicular to the drive axis 16. The minimum spacing 112 of the sealing gap element 40 to the drive axis 16 preferably extends from the inner surface 60 of the sealing gap element 40 to the drive axis 16.
[0042]