Separation plate, plate package and centrifuge

Abstract

Separating plate (7) for a plate pack (2) for use in a centrifuge, which has an inner edge (17) and an outer edge (16) which are spaced apart from one another at a maximum radial distance (A), characterized in that the separating plate (7) has rising channels (12), the center of which, starting from the inner edge (17), is less than 20% of the maximum radial distance (A) and that the separating plate (7) has, in the radial direction beyond the rising channels (12), only tabs (9, 10) which have a length of less than three times their width.

Description

[0001] The present invention relates to a separation plate, as well as a plate pack and a centrifuge.

[0002] Many variants of separation discs with flaps are known from the state of the art. However, it is often the case that the separation discs have risers in an outer edge or central area, with the flaps arranged above these risers in the direction of the rotation axis. These have generally proven to be effective. However, in isolated applications of centrifugal separation and / or clarification, backmixing can occur in the area of ​​the flaps. An example of flaps on both sides of the risers, i.e., radially inside and outside, is given, for example, in DE 10 2019 130 796 A1 or EP 3 501 659 A1.

[0003] It may also happen that longitudinal plates on separating plates between the risers are used instead of point plates. Examples of this would be DE 202021104728 U1 or DE 10 2013 101 654 A1.

[0004] Based on the aforementioned prior art, it is now the object of the present invention to provide a separation plate which allows a more efficient separation of a light phase, particularly when a large amount of heavy phase is discharged.

[0005] The present invention solves this problem by providing a separating plate with the features of claim 1.

[0006] A separating disc according to the invention is intended for a disc stack for use in a centrifuge. The separating disc typically has an inner edge and an outer edge. The two edges are spaced apart at a maximum radial distance.

[0007] The separating plate also has riser channels whose center is less than 20% of the maximum radial distance from the inner edge.

[0008] In the radial direction beyond the riser channels, the separating plates only have tabs that are less than three times longer than their width.

[0009] The tabs described above are described below as point tabs, whereby the shape of the tabs, as previously defined, can also deviate from the optimal point shape.

[0010] The arrangement of the riser channels on the inside allows for longer contact of the heavy phase with the surface of the separation plate, thus resulting in a quantitatively better separation of the light phase when a large amount of heavy phase is present. This is the case, for example, when separating cream from skim milk.

[0011] The arrangement of point flaps instead of longitudinal flaps reduces the buildup of a cream-skim milk mixture on the flaps, especially in their flow shadows, when milk is transferred over the separating disc. Furthermore, flaps with a smaller flow cross-section reduce turbulence on the disc surface and the resulting backmixing of cream and skim milk. Furthermore, the shear stress, especially on cream, is lower with smaller flaps, thus reducing mechanical stress on the cream and even unintentional churning.

[0012] Advantageous embodiments of the separating plate are the subject of the subclaims.

[0013] It is advantageous if, at least in some areas, longitudinal tabs are arranged between the riser channels, with a length greater than three times their width. These longitudinal tabs prevent rotation of the light phase, e.g., cream, and shearing of the light phase in the area of ​​the riser channels.

[0014] The longitudinal tabs can preferably be arranged in the radial direction on the separating plate.

[0015] Apart from the riser channels, the separating plate is designed as a circumferentially closed surface between the inner and outer edges.

[0016] The aforementioned riser channels, whose centers are located less than 20% of the maximum radial distance (A) from the inner edge, are the only riser channels on the separation plate. Therefore, a central or lower-lying discharge of the heavy phase at another location on the separation plate is not provided.

[0017] The riser channels cannot extend beyond 20% of the maximum radial distance from the inner edge. Thus, not only the center but also the extent of the riser channels is defined. Discharge beyond the previously defined area from the plate surface is therefore not possible.

[0018] It is also advantageous if the longitudinal tabs do not extend beyond the radial extent of the riser channels starting from the inner edge.

[0019] The length of the longitudinal tab in the radial direction in relation to its width may have a ratio of at least 5:1, preferably more than 8:1.

[0020] It is also advantageous if the longitudinal tabs do not extend beyond half the radial extent of the risers. This prevents unintentional diversion past the risers.

[0021] Some of the tabs, which are designed as point tabs, can be arranged in radial alignment with the center of the riser channels.

[0022] It is also advantageous if the tabs in radial alignment with the center of the riser channels are spaced closer to each other, preferably at least twice as far apart, in the radial direction than the tabs outside the aforementioned alignment. This allows for better radial flow guidance through the tabs without causing shearing, since part of the product is still guided between the tabs.

[0023] The distance between the tabs in radial alignment to the center of the riser channels can be at least twice as large as their longitudinal extension.

[0024] Furthermore, it is advantageous if some of the tabs, preferably all of the tabs, of the separating plate are welded.

[0025] The separating plate can particularly preferably be conical, preferably as a conical sheet which, apart from the tabs, has a uniform wall thickness.

[0026] Some of the tabs may be ovoid and / or ellipsoid.

[0027] Also according to the invention are a disk stack comprising the separating disk according to the invention and a centrifuge comprising the disk stack according to the invention. The disk stack can have at least one or more separating disks.

[0028] More than 90% of all separating discs can have an identical shape. This significantly improves centrifugal processing efficiency. Adjacent separating discs in a disc stack rest on the tabs, especially on all tabs of the separating disc.

[0029] It is also advantageous if the plate package has an axis of symmetry and if the centers of all riser channels of the separating plates lie one above the other on a connecting axis, which are arranged parallel to the axis of symmetry.

[0030] A centrifuge according to the invention is provided with a rotatably mounted centrifuge drum and a disk pack according to the invention rigidly arranged relative to the rotatably mounted centrifuge drum, wherein the disk pack is arranged within the centrifuge drum.

[0031] The invention is explained in more detail below using an embodiment with the aid of the enclosed figures.

[0032] They show: Fig. 1 a sectional view of a separating plate according to the invention; Fig. 2 a side view of the separating plate of the Fig. 1; Fig. 3 a perspective view of the separating plate of the Fig. 1 and Fig. 2; Fig. 4 a top view of the separating plate of the Fig. 1-3; and Fig. 5 a schematic representation of a separation plate and a plate pack in a centrifuge drum of a centrifuge.

[0033] Fig. Figure 5 shows a schematic representation of a centrifuge 100 designed as a separator with a centrifuge drum 1, into which a separating plate package 2 with an axis of symmetry S is inserted. The function of such nozzle separators with an inlet 3 and outlets 4, 5, 6 has long been generally known and therefore requires no further explanation. Fig. 5 riser channels shown only schematically, in this figure not corresponding to the actual position when using separating plates according to the invention.

[0034] Fig. 1-4 show various representations of a separating plate 7 according to the invention of a separating plate stack 2 with several identically shaped separating plates stacked one above the other. These can preferably be made of sheet steel.

[0035] In the figures, a separating plate 7 is designed as a conical, in particular hollow truncated cone-shaped, closed-walled outer surface 8, preferably with a uniform wall thickness. Due to the conical shape, the outer surface 8 also has a longitudinal axis L, which, with respect to a separator according to the invention, is arranged coaxially with its axis of rotation.

[0036] Below, an extension of the tabs on this surface is explained using the lateral surface as an example. There is an arrangement of tabs on a common orbit U around the lateral surface 8. This orbit is defined by a circular path that runs exclusively on a plane perpendicular to the longitudinal axis L.

[0037] A radial extension R runs along the lateral surface 8, perpendicular to the orbit U and inclined by the cone angle K relative to the longitudinal axis L.

[0038] The separating plate 7 also has an inner edge 17, at which the conical shape of the lateral surface 8 begins, and an outer edge 16, at which the conical shape of the lateral surface 8 ends. The inner edge 17 and the outer edge 16 are spaced apart by a maximum distance A. If the inner edge or outer edge has notches that reduce the distance compared to the other edge, the maximum distance must be determined outside these notches.

[0039] From the inner edge 17, the separating plate 7 can have a collar 14 which extends from the lateral surface, perpendicularly in the direction of the longitudinal axis L and which therefore does not lie on the conical shape of the lateral surface 8. The collar 14 can also have recesses 15 which enable additional anti-twist protection of the respective separating plate.

[0040] Projections, so-called tabs 9, 10, and 11, protrude from the lateral surface 8, preferably in the direction of a respective surface normal to this lateral surface 8. Tabs on the surface of a separating plate 2 are known per se. They serve to define a minimum distance between the plates. The tabs can, for example, be welded on in a defined shape.

[0041] The tabs 9 and 10 are designed as so-called point tabs. Point tabs as defined in the present application have a radial extension that does not exceed three times their extension on the orbit. The point tabs can therefore be circular or, as in Fig. 2-4 recognizable, slightly ovoid in shape.

[0042] Furthermore, in the area of ​​the inner edge 17, so-called longitudinal tabs 11 with a radial extension of more than three times the extension on the orbit protrude from the lateral surface 8.

[0043] Furthermore, in the inner edge-side upper quarter of the separation plate 7, several riser channels 12 are arranged on a circular path U. This arrangement of the riser channels 12 relative to the axis of rotation enables, for example, in the case of centrifugal separation of cream from milk, separation of skimmed milk with the lowest possible residual cream content, whereas discharge through riser channels in the middle region results in lower separation efficiency with simultaneous backmixing of a certain proportion of skimmed milk in the cream, since less effective clarification surface is available up to the riser channel.

[0044] Furthermore, the longitudinal tabs 11 are arranged within the upper 20% of the total extension of the separating plate 7 in the radial direction. The longitudinal tabs 11 are preferably arranged exclusively in this area. The longitudinal tabs 11 extend at least partially or completely into the space 13 between two riser channels 12. This prevents rotation of the cream and thus mixing between the riser channels. Shearing is also advantageously prevented.

[0045] The separating plate in Fig.1-4 is designed such that the point tabs 9, in radial alignment with the center of the riser channels, are spaced apart from each other by a smaller distance, preferably at least twice as small, in the radial direction than the point tabs 10 outside the aforementioned alignment. The point tabs enable flow to be directed toward the riser channels without excessive flow blockage or excessive accumulation in the area of ​​the tabs. Reference symbol 100 centrifuge 1 centrifuge drum 2 separator plate packages 3 Inlet 4 Procedure 5 Procedure 6 Procedure 7 separating plates 8 Shell surface 9 Tab (point tab) 10 tab (point tab) 11 Tab (longitudinal tab) 12 Riser channel 13 space 14 collars 15 recesses 16 Outer edge 17 inner edge L Longitudinal axis U orbit K Cone angle R radial extension A maximum distance S axis of symmetry QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2019 130 796 A1

[0002] EP 3 501 659 A1

[0002] DE 202021104728 U1

[0003] DE 10 2013 101 654 A1

[0003]

Claims

[1] Separating plate (7) for a plate pack (2) for use in a centrifuge, which has an inner edge (17) and an outer edge (16) which are spaced apart from each other at a maximum radial distance (A), characterized by that the separating plate (7) has riser channels (12) whose center, starting from the inner edge (17), is less than 20% of the maximum radial distance (A) and that the separating plate (7) has, in the radial direction beyond the riser channels (12), only tabs (9, 10) which have a length of less than three times their width. [2] Separating plate according to claim 1, characterized by that longitudinal tabs (11) are arranged at least in some areas between the riser channels (12) and have a length which is greater than three times their width. [3] Separating plate according to claim 1 or 2, characterized by that the longitudinal tabs (11) are arranged in the radial direction on the separating plate (7). [4] Separating plate according to one of the preceding claims, characterized by that, apart from the riser channels (12), the separating plate (7) between the inner edge (17) and the outer edge (16) is designed as a circumferentially closed surface. [5] Separating plate according to one of the preceding claims, characterized by that the riser channels (12), the center of which is less than 20% of the maximum radial distance (A) from the inner edge (17), are the only riser channels (12) of the separating plate (7). [6] Separating plate according to one of the preceding claims, characterized by that the riser channels (12) do not extend beyond 20% of the maximum radial distance (A) starting from the inner edge (17). [7] Separating plate according to one of the preceding claims, characterized by that the longitudinal tabs (11) do not extend from the inner edge (17) beyond the radial extent of the riser channels (12). [8] Separating plate according to one of the preceding claims, characterized by that the length of the longitudinal tab (11) in the radial direction has a ratio of at least 5:1, preferably more than 8:1, to its width. [9] Separating plate according to one of the preceding claims, characterized by that the longitudinal tabs (11) do not extend beyond half the radial extent of the riser channels (12). [10] Separating plate according to one of the preceding claims, characterized by that a part of the tabs (9) is arranged in radial alignment with the center of the riser channels (12). [11] Separating plate according to claim 10, characterized by that the tabs (9) in radial alignment with the center of the riser channels (12) have a smaller distance from one another, preferably at least twice as small a distance from one another, in the radial direction than the tabs (10) outside the aforementioned alignment. [12] Separating plate according to one of the preceding claims 10 or 11, characterized by that the distance between the tabs (9) in radial alignment to the center of the riser channels is at least twice as large as their longitudinal extent. [13] Separating plate according to one of the preceding claims, characterized by that some of the tabs (9-11), preferably all tabs (9-11), of the separating plate (7) are welded on. [14] Separating plate according to one of the preceding claims, characterized by that the separating plate (7) is conical, preferably as a conical sheet which, apart from the tabs (9-11), has a uniform wall thickness. [15] Separating plate according to one of the preceding claims, characterized by that a part of the tabs (9, 10) is ovoid and / or ellipsoid. [16] Centrifuge disk pack, characterized bythat the plate package (2) has at least one or more separating plates (7) according to one of the preceding claims. [17] Plate package according to one of the preceding claims, characterized by that more than 90% of all separating plates (7) of the plate package (2) have an identical shape. [18] Plate package according to one of the preceding claims, characterized by that adjacent separating plates (7) rest on the tabs (9-11), in particular on all tabs (9-11) of a separating plate (7). [19] Plate package according to one of the preceding claims, characterized by that the plate package (2) has an axis of symmetry (S), and that the centers of the riser channels (12) of all separating plates (7) according to one of the preceding claims lie one above the other on a connecting axis which is arranged parallel to the axis of symmetry (S). [20] Centrifuge (100) with a rotatably mounted centrifuge drum (1) and a plate pack (2) arranged rigidly relative to the rotatably mounted centrifuge drum (1) according to one of the preceding claims, which is arranged within the centrifuge drum (1).

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