INLET REGION OF A CENTRIFUGE SCREW, AND SOLID BOWL CENTRIFUGE

Abstract

The invention relates to: an inlet region (80) of a centrifuge screw (30), the centrifuge screw (30) having, at least in the inlet region (80), a screw hub (32) with an open wall structure, in particular with longitudinal bars (58); and an inlet tube opening (47) of an inlet tube (46), the inlet tube opening (47) opening into the inlet region (80). Opposite the inlet tube opening (47) there is an impact element (70), in particular an impact disc, having an acceleration element (75), the acceleration element (75) being designed such that a medium impinging on the acceleration element (75) can be accelerated in the direction of open spaces (85) of the open wall structure, said open spaces being in particular between the longitudinal bars (58).

Claims

1. An inlet region (80) of a centrifuge screw (3), the centrifuge screw (30) having, at least in the inlet region (80), a screw hub (32) with an open wall structure, in particular with longitudinal bars (58), wherein an inlet tube opening (47) of an inlet tube (46) opens into the inlet region (80), wherein opposite the inlet tube opening (47), there is formed an impact element (70), in particular an impact disc, having an acceleration element (75), wherein the acceleration element (75) is designed such that a medium impinging on the acceleration element (75) can be accelerated in the direction of free spaces (85) of the wall structure, said free spaces being in particular formed between the longitudinal bars (58).

2. The inlet region (80) according to claim 1, characterized in that the free spaces (85) constitute outflow openings for the medium.

3. The inlet region (80) according to claim 1, characterized in that the inlet region (80) is not designed as an inlet chamber having massive and mostly closed walls.

4. The inlet region (80) according to claim 1, characterized in that in the region between the inlet tube opening (47) and the acceleration element (75), no further medium directing installations are formed.

5. The inlet region (80) according to claim 1, characterized in that the acceleration element (75) has struts (88), which are in particular arranged in a cross-shape to one another.

6. The inlet region (80) according to claim 5, characterized in that the height (H) of the struts (88) increases in the direction of a point of intersection (89) of the struts (88).

7. The inlet region (80) according to claim 1, characterized in that the acceleration element (75) is formed as a protrusion protruding from the impact element (70) and pointing in the direction of the inlet tube opening (47), and which preferably has several radial flanks (95).

8. The inlet region (80) according to claim 7, characterized in that channels (96) are formed between the flanks (95), wherein the channels (96) have a swirling course.

9. The inlet region (80) according to claim 1, characterized in that the acceleration element (75) is formed as a protrusion protruding from the impact element (70) and pointing in the direction of the inlet tube opening (47), and which has several impact surfaces (98) arranged obliquely to the longitudinal extension of the inlet region (80).

10. The inlet region (80) according to claim 1, characterized in that, to the impact element (70), in particular to the impact disc, several oblique struts (64) are attached stabilizing the screw hub (32).

11. A solid bowl screw centrifuge (10) comprising a centrifuge screw (30) located within a drum (16), wherein the centrifuge screw (30), at least in the inlet region (80), comprises a screw hub (32) which has an open wall structure, in particular longitudinal bars (58) and/or is created of longitudinal bars (58), characterized in that the inlet region (80) is formed according to claim 1.

12. The solid bowl screw centrifuge (10) according to claim 11, characterized in that free spaces (85) are formed within the wall structure, in particular between the longitudinal bars (58), and constitute outflow openings in the direction of a drum interior (65) created between the screw hub (32) and a drum inner surface (17).

13. The solid bowl screw centrifuge (10) according to claim 11, characterized in that the inlet region (80) can be variably positioned.

14. The solid bowl screw centrifuge (10) according to claim 13, characterized in that the variable position of the inlet range (80) is adjustable by positioning the impact element (70) and by selecting the length of the inlet tube (46).

15. The solid bowl screw centrifuge (10) according to claim 11, characterized in that the longitudinal extension of the inlet range (80) is at most 50% of the total length of the centrifuge screw (30), in particular at most 33% of the total length of the centrifuge screw (30), in particular at most 25% of the total length of the centrifuge screw (30).

Description

[0063] Shown are in:

[0064] FIG. 1 a longitudinal cut of the solid bowl screw centrifuge according to the invention, which has an inlet region according to the invention;

[0065] FIGS. 2a and 2b a first embodiment of an acceleration element;

[0066] FIGS. 3a and 3b a representation of a further embodiment according to the invention of an acceleration element; and

[0067] FIGS. 4a and 4b a representation of a further embodiment according to the invention of an acceleration element.

[0068] In the following, the same reference numerals will be used for identical parts or parts of identical action.

[0069] In FIG. 1, a solid bowl screw centrifuge 10 is represented, which extends substantially along a horizontal longitudinal axis 12. The solid bowl screw centrifuge 10 has an outer housing 14, in which a drum 16 is mounted to be rotational about the longitudinal axis 12. By rotating the drum 16 at high rotational speed, a centrifugal force can be generated within it, by means of which a product to be clarified can be separated into a heavy phase and a light phase. For this purpose, the drum 16 is supported on a first drum bearing 18 and a second drum bearing 20. The represented solid bowl screw centrifuge 10 is a 2-phase solid bowl screw centrifuge. The inlet region according to the invention can be realized, however, in a 3-phase solid bowl screw centrifuge as well.

[0070] At the drum 16, an inlet 22 for the product to be clarified and an outlet 24 for the heavy phase and an outlet 26 for the light phase are formed. For rotating the drum 16, a drive 28 is formed.

[0071] The outlet 26 acts as an overflow for the light phase located radially inside the drum 16, so that the light phase exits there autonomously, if a predetermined level, the so-called pond depth 52, is reached within the drum.

[0072] At the drum 16, two front sides, namely a first front side 13 and a second front side 15 are moreover formed. The first front side 13 is in this case assigned to the area of the outlet 26 for the light phase. The second front side 15 in turn is assigned to the area of the outlet 24 for the heavy phase.

[0073] Furthermore, the longitudinal direction R is represented. The longitudinal direction R substantially runs in parallel to the longitudinal axis 12. The longitudinal direction R is defined in the represented example as the direction of transportation of the solid discharge. Accordingly, the first front side 13 is the first front side of the drum 16 in the longitudinal direction R. The second front side 15 is the second front side of the drum 16 in the longitudinal direction R.

[0074] So that the heavy phase located radially outside within the drum can be discharged from the drum 16, a centrifuge screw 30 is provided within the drum 16. The centrifuge screw 30 is rotated relative to the drum 16 by means of the drive 28. Thereby, the material of the heavy phase is discharged to radially inside and thus to the outlet 24 along a cone formed at the drum 16.

[0075] For this purpose, the centrifuge screw 30 is configured with a screw hub 32 extending longitudinally to the longitudinal axis 12, which screw hub is surrounded radially outside by a screw spiral coil 34. The screw hub 32 consequently serves the purpose of supporting the screw spiral coil 34 in the radial direction, of transmitting torque from the drive 28 to the screw spiral coil 34, and of receiving in particular tensile forces and thrust forces in this case. The screw hub 32 is configured by a grid structure 56 in the cylindrical longitudinal section 36.

[0076] The grid structure 56 has twelve longitudinal bars 58, which are arranged to be distributed at uniform distances across the circumference of the screw hub 32 in the longitudinal direction thereof, thus in parallel to the longitudinal axis 12. In the represented exemplary embodiment, the open wall structure thus is created due to the longitudinal bars 58. Alternative embodiments for constituting an open wall structure are possible. By way of example, an open wall structure may be created by forming a plurality of longitudinal slots in the screw hub 32.

[0077] The preferred number of longitudinal bars 58 is between 8 and 16, in particular between 10 and 14. Radially outside, the longitudinal bars 58 each constitute a contact surface for the screw spiral coil 34 and are supported radially inside on transverse discs 60. The longitudinal bars 58 extend in this case beyond the transverse discs 60, which are oriented transversely to the longitudinal axis 12 and thus form an inner support for the longitudinal bars 58.

[0078] Between two and six oblique struts 64 extend between each of two transverse discs 60. Particularly preferred, three oblique struts 64 are formed.

[0079] Within the conical longitudinal section 38, a screw hub 32 having a shell surface 44 is formed. The shell surface 44 is substantially closed and in particular configured by means of a sheet metal or a tube surface. The centrifuge screw 30 is mounted to be rotatable by means of a first screw bearing 40 and a second screw bearing 42.

[0080] In FIG. 1, an inlet tube 46 can be recognized furthermore. Through this inlet tube 46, the medium to be separated gets into the solid bowl screw centrifuge 10. The inlet tube 46 has an inlet tube opening 47.

[0081] The inlet tube 46 serves the purpose of supplying the product to be clarified centrally in the inlet region 80 and into the interior of the screw hub 32. The inlet region 80 in FIG. 1 is to be understood as being that section, which is represented between the two dashed lines. The inlet region is delimited in one direction by the inlet tube opening 47. Opposite the inlet tube opening 47, an impact element 70 is formed. In other words, the inlet region 80 of the screw hub 32 extends at least from the inlet tube opening 47 up to the impact element 70.

[0082] The impact element 70 is formed in the present case as an impact disc. On the impact element 70, an acceleration element 75 is formed. The acceleration element 75 is substantially formed as a protrusion pointing from the impact element 70 in the direction of the inlet tube opening 47.

[0083] It can be recognized that the inlet region 80 is defined as such an area, which is formed between the inlet tube opening 47 and the impact element 70. In other words, the inlet region 80 is the area, which is formed due to the distance between the inlet tube opening 47 and the impact element 70. In this case, not only the perpendicular between the inlet tube opening 47 and the impact element 70, as can be recognized by the dashed representation, is to be understood as the inlet region 80, but also the complete radial space within the screw hub 32 having an extension in the longitudinal direction R, which corresponds to the distance between the inlet tube opening 47 and the impact element 70. In other words, the inlet region 80 may concern a cylindrical space.

[0084] In other words, the described distance between the inlet tube opening 47 and the impact element 70 corresponds to the longitudinal extension in the longitudinal direction of the inlet region 80. Preferably, the longitudinal extension of the inlet region 80 is at maximum 50% of the total length of the cylindrical longitudinal section 36.

[0085] The inlet region 80 in the represented example is formed to be approximately central in the cylindrical longitudinal section 36. In particular the impact element 70, in particular the impact disc, is formed in a central section of the cylindrical longitudinal section 36. The position of the inlet region 80, in particular the position of the impact element 70, may be formed in an impact element arrangement region 90. The maximum position of the impact element 70 is in this case formed in the transition area from the cylindrical longitudinal section 36 to the conical longitudinal section 38. In this case, the impact element 70 is formed as an end disc of the cylindrical longitudinal section 36. Furthermore, it is conceivable for the impact element 70 to be formed at the shown positions of the transverse discs 60. The first transverse disc 60 in the longitudinal direction R preferably is located at a position having a distance to the beginning of the screw 30, which corresponds at maximum to a third, at maximum to a fourth, at maximum to a fifth of the total length of the centrifuge screw 30.

[0086] Due to positioning of the impact element 70 and by correspondingly selecting the length of the inlet tube 46, the position of the inlet region 80 can be variably designed. The variable design of the position of the inlet region 80 basically is advantageous, since with the help of a variable position of the inlet region 80, an optimum inlet position for various media as well as for various throughputs can be realized in each case.

[0087] The acceleration element 75 is formed such that a medium impinging on the acceleration element 75 or the product to be clarified can be accelerated in the direction of free spaces 85 of the open wall structure. In the represented example, the free spaces 85 are formed between the longitudinal bars 58 of the screw hub 32. The free spaces 85 are created due to the distance formed in each case between the longitudinal bars 58. The free spaces 85 serve as outflow openings for the medium.

[0088] The product to be separated or the medium gets into the drum interior 65, which may also be referred to as a separating space, via the free spaces 85. The space, which is created between the drum 16 or the drum inner surface 17 and the screw hub 32 may be referred to as the drum interior 65. The size of the available openings, through which the medium can get from the inlet region 80 into the drum interior 65, is defined based on the size of the free spaces 85 and thus based on the distance formed between the longitudinal bars 58. These explanations apply in conjunction with all of the represented embodiments of the inlet region 80 or the acceleration element 75 according to the invention.

[0089] The acceleration element 75 causes the medium to be pre-accelerated and additives to be better mixed in.

[0090] In FIGS. 2a and 2b, FIGS. 3a and 3b, as well as FIGS. 4a and 4b, three different embodiments of acceleration elements are represented.

[0091] FIG. 2a shows a top view of an impact element 70. For better representability of the impact element and the acceleration element 75, further components of the screw hub 32 are not represented completely in the top view.

[0092] It can be recognized that the screw hub 32 is formed inter alia by longitudinal bars 58. In the present case, twelve longitudinal bars 58 are formed. The impact element 70 inter alia serves for stabilizing the screw hub 32. For this purpose, the impact element 70 has recesses 71 into which the longitudinal bars 58 are inserted.

[0093] Furthermore, a screw spiral coil 34 is represented schematically. This spiral coil extends helicoidally in the longitudinal extension of the longitudinal bars 58. The impact element 70, which may be referred to as an impact disc, has the acceleration element 75.

[0094] As can be recognized in FIG. 2b, the acceleration element 75 has four struts 88 arranged in a cross-shape to one another. The point of intersection 89 constitutes at the same time the point of the acceleration element 75 having the largest height in relation to the impact element 70. Furthermore, it can be recognized that the heights H of the struts 88 increase in the direction of the point of intersection 89. The struts 88 themselves are arranged on a disc 87. Accordingly, it is possible for the acceleration element 75 to be first produced as an intermediate element or an autonomous assembly.

[0095] In other words, the height H of the struts 88 respectively increases starting from the circumference U of the disc 87 in the direction of the point of intersection 89.

[0096] In a further embodiment of the invention (not represented) additional struts may be arranged so that these struts 88 can constitute a star-shape. It is moreover possible for the struts 88 to have no edges 84 and to be formed rounded. An arcuate course of the struts 88 is also possible.

[0097] The free spaces 85 are formed between the longitudinal bars 58. The free spaces 85 thus constitute the outflow openings for the medium or the product to be clarified.

[0098] The point of intersection 89 of the acceleration element 75 is in particular formed on the longitudinal axis 12 of the solid bowl screw centrifuge.

[0099] In addition, oblique struts 64 (not represented) may be attached to the impact element 70. This serves in particular for stabilizing the screw hub 32.

[0100] A further embodiment of a potential inlet region 80 is at least in part represented in FIG. 3a. In the following, only the difference from the embodiment according to FIGS. 2a and 2b will be discussed. Accordingly, the acceleration element 75 directly arranged on the impact element 70 is formed differently.

[0101] In FIG. 3b, this is represented more clearly. The acceleration element 75 is formed as a protrusion protruding from the impact element 70. Several radial flanks 95 can be recognized. Between the flanks 95, channels 96 are created.

[0102] Both the flanks 95 and the channels 96 have a swirling course. Starting from the central point M of the acceleration element 75, the flanks 95 and thus the channels 96 formed between the flanks 95 run in a swirling manner in the direction of the circumference V. If a medium to be clarified impinges on the central point M of the acceleration element 75, pre-acceleration of the medium or the product to be clarified can take place due to the channels being formed in a swirling manner.

[0103] A further embodiment of a potential inlet region 80 is at least in part represented in FIG. 4a. In the following, only the difference from the embodiment according to FIGS. 2a and 2b will be discussed. Accordingly, the acceleration element 75 directly arranged on the impact element 70 is formed differently.

[0104] In FIG. 4b, this is represented more clearly. The acceleration element 75 is formed as a protrusion protruding from the impact element 70. The protrusion has several impact surfaces 98 arranged obliquely to the longitudinal extension of the inlet region 80. The impact surfaces 98 are arranged to one another in such a manner that a pyramidal protrusion shape is created. The protrusion, however, does not have a tip. The impact surfaces 98 rather have flattening segments 99 respectively.

LIST OF REFERENCE NUMERALS

[0105] 10 solid bowl screw centrifuge

[0106] 12 longitudinal axis

[0107] 13 first front side

[0108] 14 outer housing

[0109] 15 second front side

[0110] 16 drum

[0111] 17 drum inner surface

[0112] 18 first drum bearing

[0113] 20 second drum bearing

[0114] 22 inlet for the product to be clarified/medium

[0115] 24 outlet for the heavy phase

[0116] 26 outlet for the light phase

[0117] 28 drive

[0118] 30 centrifuge screw

[0119] 32 screw hub

[0120] 34 screw spiral coil

[0121] 36 cylindrical longitudinal section

[0122] 38 conical longitudinal section

[0123] 40 first screw bearing

[0124] 42 second screw bearing

[0125] 44 closed shell surface

[0126] 46 inlet tube

[0127] 47 inlet tube opening

[0128] 52 pond depth

[0129] 56 grid structure

[0130] 58 longitudinal bar

[0131] 60 transverse disc

[0132] 64 oblique disc

[0133] 65 drum interior/separating space

[0134] 70 impact element

[0135] 71 recess

[0136] 75 acceleration element

[0137] 80 inlet region

[0138] 84 edge

[0139] 85 free space

[0140] 87 disc

[0141] 88 strut

[0142] 89 point of intersection

[0143] 90 impact element arrangement region

[0144] 95 flank

[0145] 96 channel

[0146] 98 impact surface

[0147] 99 flattening segments

[0148] H height of strut

[0149] M central point

[0150] R longitudinal direction

[0151] U circumference of disc

[0152] V circumference of acceleration element