SCREW HUB, CENTRIFUGAL SCREW, AND SOLID BOWL SCREW CENTRIFUGE

Abstract

The invention relates to a screw hub (10) for a centrifugal screw (80), said screw hub (10) having, in the longitudinal direction (R), at least one cylindrical longitudinal portion (11) and a portion (12) at the solid-discharge end, the cylindrical longitudinal portion (11) having an open wall structure (40), and the portion (2) at the solid-discharge end having an at least partly closed shape that differs from a simple conical shape.

Claims

1. A screw hub (10) for a centrifugal screw (80), wherein the screw hub (10) in the longitudinal direction (R) has at least one cylindrical longitudinal portion (11) and a portion (12) at the solid-discharge end, wherein the cylindrical longitudinal portion (11) at least in sections has an open wall structure (40), and the portion (12) at the solid-discharge end has an at least partially closed shape deviating from a simple cone shape.

2. The screw hub (10) according to claim 1, characterized in that the portion (12) at the solid-discharge end is designed to be a cylinder portion (45) and/or a cylindrical tube portion.

3. The screw hub (10) according to claim 2, characterized in that the cylinder portion (45) and/or the cylindrical tube portion are designed to be stepped such that the cylinder portion (45) and/or the cylindrical tube portion have/has at least two portions having different diameters in the longitudinal direction (R) of the screw hub (10).

4. The screw hub (10) according to claim 1, characterized in that the portion (12) at the solid-discharge end has a double truncated cone shape (70).

5. The screw hub (10) according to claim 1, characterized in that the cylindrical longitudinal portion (11) consists of an open wall structure (40).

6. The screw hub (10) according to claim 1, characterized in that the open wall structure (40) at least in sections is formed by a plurality of web elements delimiting a plurality of openings, wherein the web elements relative to a longitudinal axis are arranged to be radially outside at the cylindrical longitudinal portion and form a circumference of the longitudinal portion, wherein two web elements each form a web pair delimiting at least one opening, wherein the two web elements of the web pair extend in the longitudinal direction and transversely to the longitudinal direction, or a first web element of the web pair respectively extends in the longitudinal direction, and a second web element of the web pair respectively extends transversely to the longitudinal direction.

7. The screw hub (10) according to claim 1, characterized in that the open wall structure (40) at least in sections is formed by a tube in which a plurality of openings is designed for the passage of a medium, wherein the openings each have a longitudinal extension which is larger than the width of the respective opening.

8. The screw hub (10) according to claim 1, characterized in that the open wall structure (40) at least in sections is formed by longitudinal rods (41).

9. A centrifugal screw (80) having a screw hub (10) according to claim 1, and a screw spiral (20) surrounding the screw hub (10).

10. A solid bowl screw centrifuge comprising a centrifugal screw located within a drum, wherein the screw hub (10) of the centrifugal screw is designed according to claim 1.

Description

[0069] In these are shown:

[0070] FIG. 1 a longitudinal cut through a centrifugal screw having a screw hub according to the invention according to a first exemplary embodiment; and

[0071] FIG. 2 a longitudinal cut through a centrifugal screw having a screw hub according to the invention according to a further exemplary embodiment according to the invention.

[0072] In the following, the same reference numerals will be used for equal part or parts having the same action.

[0073] In FIG. 1, a centrifugal screw 80 according to the invention having a screw hub 10 according to the invention is presented. The screw hub has a cylindrical longitudinal portion 11 and a portion 12 at the solid-discharge end in the longitudinal direction R.

[0074] The longitudinal direction R essentially extends in parallel to the longitudinal axis L of the screw hub 10. In the present case, the longitudinal direction R is defined as the direction of transport of the solid material discharge. According to the illustration of FIG. 1, the solid material transport is performed up to the solid material discharge from the right to the left side.

[0075] The screw hub 10 of the centrifugal screw 80 is constituted by all of the illustrated portions and components except for the screw spiral 20. The screw spiral 20 cannot be designed or defined as being associated to the screw hub 10. The screw spiral 20 is to be defined as being a part of the centrifugal screw 80.

[0076] In the present case, the longitudinal portion 11 is designed to be longer than the portion 12 at the solid-discharge end.

[0077] The illustration of the portion 12 at the solid-discharge end makes clear that this portion does not only relate to the first frontal side 31 of the screw hub 10, but rather is to be understood as being a functional portion serving in particular the transport of the solid material separated from the material to be processed into the direction R of the solid material discharge.

[0078] The cylindrical longitudinal portion 11 has an open wall structure 40. The open wall structure 40 is formed by several longitudinal rods 41 and transverse discs 42 stabilizing these longitudinal rods 41. The longitudinal rods 41 are arranged to be evenly distributed in equal distances across the circumference of the screw hub 10 in the longitudinal direction R thereof, thus in parallel to the longitudinal axis.

[0079] As is explained in the previous description, the open wall structure may also be formed by web elements, specifically web pairs.

[0080] Alternatively, it is possible for the open wall structure to be formed by a tube in which a plurality of openings is designed for the passage of a medium.

[0081] The cylindrical longitudinal portion 11 extends from a second frontal side 32 of the screw hub 10 up to a connecting disc 50. The connecting disc 50 serves for connecting the cylindrical longitudinal portion 11 to the portion 12 at the solid-discharge end.

[0082] The cylindrical longitudinal portion 11 furthermore comprises a bearing portion 60 for supporting the illustrated centrifugal screws 80 in a drum (not illustrated) of a solid bowl screw centrifuge.

[0083] In the present case, the portion 12 at the solid-discharge end is designed to be a cylinder portion 45. The cylinder portion is formed by a solid material and has an equal outer diameter across the entire longitudinal extension of the portion 12 at the solid-discharge end.

[0084] By means of such a cylinder portion, a particularly low-wear screw hub 10 is formed contributing additionally for relaxing a solid material to be transported in the area of the portion 12 at the solid-discharge end.

[0085] It is possible for the portion 12 at the solid-discharge end to be formed by a cylindrical tube portion. In this case, a hollow cylinder would be designed.

[0086] According to the exemplary embodiment of FIG. 1, the screw spiral 20 extends over the entire longitudinal extension of the screw hub 10. The screw spiral 20 is arranged both on the cylindrical longitudinal portion 11 and the portion 12 at the solid-discharge end.

[0087] In FIG. 2, a further embodiment of a screw hub 10 according to the invention or of a centrifugal screw 80 according to the invention is illustrated. The contrast to the embodiment illustrated in FIG. 1 is related to the portion 12 at the solid-discharge end. The cylindrical longitudinal portion 11 of the screw hub 10 has a design corresponding to the embodiment according to FIG. 1.

[0088] The portion 12 at the solid-discharge end has a double truncated cone shape 70. The double truncated cone shape 70 is formed by two truncated cones, i.e., a first truncated cone 71 and a second truncated cone 72.

[0089] The first truncated cone 71 is designed to lie next to the cylindrical longitudinal portion or to be connected to it. The second truncated cone 72, however, points into the direction of the first frontal side 31 of the screw hub 10 or comprises the first frontal side 31 of the screw hub 10.

[0090] The two truncated cones 71 and 72 are arranged relative to each other such that the respective (imaginary) surface areas in the connecting portion 73 are designed to adjoin each other.

[0091] The cover surface 75 of the first truncated cone 71 and the cover surface of the second truncated cone 72, however, point away from each other. The cover surface 75 of the first truncated cone 71 is adjacent to the cylindrical longitudinal portion 11. The cover surface 75 may also be an imaginary cover surface. The first truncated cone 71 may be designed to be open in the direction of the upper side.

[0092] The cover surface 76 of the second truncated cone 71, however, is actually formed. It may be designed, for example, to be a part of the first frontal side 31 of the screw hub 10.

[0093] In the presently illustrated case, the two truncated coned 71 and 72 have almost the same heights H1 and H2. It is possible for the heights H1 and H2 to be different from each other in alternative embodiments of the invention.

[0094] It is likewise possible that a connecting disc is designed between the cylindrical longitudinal portion 11 and the portion 12 at the solid-discharge end. Such a connecting disc 50, for example, is provided according to the embodiment of FIG. 1.

[0095] By means of the embodiment of the screw hub 10 illustrated in FIG. 2 it is possible that further installations of a solid bowl screw centrifuge such as, e.g., the baffle plate (not illustrated), are less stressed. Also, the screw spiral 20 is less stressed than it is the case, for example, in simple cone-shaped geometries, due to the formation of the portion 12 at the solid-discharge end.

[0096] It should be noted in conclusion that all of the features mentioned in the documents of application and in particular in the dependent claims, despite the formal back reference made to one or several certain claim/s, should receive an autonomous protection singly or in an arbitrary combination.

LIST OF REFERENCE NUMERALS

[0097] 10 screw hub [0098] 11 cylindrical longitudinal portion [0099] 12 portion at the solid-discharge end [0100] 20 screw spiral [0101] 31 first frontal side of the screw hub [0102] 32 second frontal side of the screw hub [0103] 40 open wall structure [0104] 41 longitudinal rod [0105] 42 transverse disc [0106] 45 cylinder portion [0107] 50 connecting disc [0108] 60 bearing portion [0109] 70 double truncated cone shape [0110] 71 first truncated cone [0111] 72 second truncated cone [0112] 73 connecting portion [0113] 75 cover surface of the first truncated cone [0114] 76 cover surface of the second truncated cone [0115] 80 centrifugal screw [0116] H1 height of the first truncated cone [0117] H2 height of the second truncated cone [0118] L longitudinal axis [0119] R longitudinal direction