Arrangement for delaminating a fibrous material

Abstract

The invention relates to an arrangement (1) for delaminating a fibrous material, the arrangement comprising a screw (2) and a spool (3). The invention is characterised in that the regions of greatest curvature (11) of the spool contour are arranged at or closer to an outer envelope (9) of the spool than to an inner envelope (10) of the spool, and the regions of greatest curvature (12) of the screw contour are arranged at or closer to an outer envelope (7) of the screw than to an inner envelope (8) of the screw. The invention enables advantageous delamination of the fibrous material, in particular avoiding delamination by cutting.

Description

[0001] ARRANGEMENT FOR DELAMINATING A FIBER

[0002] The invention relates to a compression screw, in particular a maceration screw or stuffing screw, comprising a screw of the compression screw and an arrangement for delaminating a fibrous material, in particular a lignocellulosic material, the arrangement comprising a screw and a spool, wherein the screw is connected to the screw of the compression screw and the screw is rotatable relative to the spool about an axis of rotation, the screw or the spool having a screw contour or a spool contour in a plane normal to the axis of rotation, wherein the screw contour is formed between an outer envelope of the screw and an inner envelope of the screw and the spool contour is formed between an outer envelope of the spool and an inner envelope of the spool.

[0003] Compression screws are well known in the prior art. These comprise a screw with a helix arranged within a housing. The screw is mounted to rotate around an axis of rotation relative to the housing. The fibrous material is fed into the compression screw via an inlet and transported by the screw from the inlet to an outlet, where the fibrous material is processed in the area between the housing and the screw, i.e., compressed, dewatered, macerated, etc. Compression screws designed as maceration screws or plugging screws are known. Maceration screws, in particular, aim to macerate the fibrous material, separating it into individual fibers as effectively as possible.

[0004] The object of the invention is an arrangement for a compression screw that allows improved delamination of a fibrous material, particularly lignocellulose, and especially avoids a cutting treatment of the fibrous material. The fibrous material processed in this way is better suited for the absorption of liquids, chemicals, etc., and subsequent process steps enable fiber processing with lower energy consumption.

[0005] According to the invention, this is achieved by arranging the areas of greatest curvature of the coil contour on or closer to the outer envelope of the coil than on the inner envelope of the coil, and by arranging the areas of greatest curvature of the worm contour on or closer to the outer envelope of the worm than on the inner envelope of the worm.

[0006] Compression screws known from the prior art typically comprise a screw with a helix, with the fibrous material being processed between the housing and the screw. The housing according to the prior art is typically free of a helix, thus giving the housing an essentially circular contour. Typically, the screw is supported on one side of the compression screw, i.e., cantilevered, with the inlet located between the outlet and the bearing. However, the screw can also be supported on both sides of the compression screw, i.e., in the inlet region and in the outlet region.

[0007] The arrangement according to the invention can, for example, be directly connected to a conventional compression screw, in particular a maceration screw or a plugging screw. The resulting screw – the screw of the arrangement and the screw of the compression screw – can be formed in one piece or in multiple pieces. The housing of the arrangement is likewise connected to the housing of the compression screw, wherein the resulting housing – housing of the arrangement and housing of the compression screw – can be formed in one piece or in multiple pieces. Advantageously, more than one arrangement according to the invention can be connected to the compression screw. Likewise, a first arrangement according to the invention can be arranged between a first compression screw and a second compression screw.The arrangement according to the invention is characterized in particular by the fact that it comprises a worm and a coil, the worm is arranged inside the coil, and the worm is rotatable relative to the coil about an axis of rotation. In particular, neither the worm nor the coil of the arrangement according to the invention has a helix. Furthermore, the worm and the coil have a worm contour and a coil contour, respectively, in a plane normal to the axis of rotation. According to the invention, the worm contour is formed between an outer envelope of the worm and an inner envelope of the worm, and the coil contour is formed between an outer envelope of the coil and an inner envelope of the coil. Firstly, the discrete envelopes of the worm and the coil are explicitly distinguishable from one another – i.e., the envelopes of the worm and the coil are discretely distinguishable.Secondly, the envelopes are typically circular and have a diameter. For example, a typical diameter of the inner envelope of the screw is between 100 mm and 950 mm, and the diameter of the outer envelope of the coil is, for example, between 130 mm and 1000 mm. According to the invention, the areas of greatest curvature of the coil contour are arranged at or closer to the outer envelope of the coil than at the inner envelope of the coil. "Outer" and "inner" are to be understood as radially outer and radially inner, respectively, starting from the axis of rotation, and "curvature" refers to the change in the direction of the contour. Furthermore, the coil is concave in the areas of greatest curvature—viewed from the inside—where "from the inside" is understood as viewed from the projecting axis of rotation. Similarly, according to the invention, the areas of greatest curvature of the screw contour are located at or closer to the outer envelope of the coil than to the inner envelope of the coil.The circular envelopes are arranged closer to the outer envelope of the helical spiral than to the inner envelope. In the regions of greatest curvature, the spiral is convex when viewed from the outside, where "from the outside" refers to the view along the projecting axis of rotation. Regarding the term "regions of greatest curvature," it can be stated that the respective circular envelopes exhibit a curvature corresponding to the inverse of their radius, with each "region of greatest curvature" having a curvature greater than that of the respective envelope.

[0008] The effect according to the invention consists of a particularly gentle singulation of the fibers or delamination of the fibrous material, whereby any cutting effect on the fibers or the fibrous material is minimized. This is achieved in particular by the kneading effect according to the invention, wherein the gap formed between the spool and the screw has a gap height that varies around the circumference as a result of the rotation of the screw. The kneading results from the compression and decompression of the fibrous material. The kneading effect is defined as the quotient of a first difference and a second difference, wherein the first difference is formed by the diameter of the outer envelope of the spool minus the diameter of the inner envelope of the screw, and the second difference is formed by the diameter of the inner envelope of the spool minus the diameter of the outer envelope of the screw.The kneading effect is thus a measure of the change in the gap height when the screw rotates in the spool, and therefore a measure of the kneading of the fiber material. The kneading effect can range from a value greater than 1 to, for example, a value of 5, where a value of exactly 1 corresponds to the kneading effect of a cylindrical annular gap.

[0009] According to the invention, the minimum gap, i.e., the minimum gap height between the spool and the screw, is achieved when the area of ​​greatest curvature of the screw contour meets an area of ​​the spool with less curvature, which is located between two areas of greatest curvature of the spool contour. Advantageously, this ensures that the fiber material is not subjected to a cutting action despite the minimal gap height.

[0010] If, on the other hand, only ribs were attached to the screw and the spool (which is not part of the invention), the minimal gap would form between the rib of the screw and the rib of the spool, and the fiber material would be cut in the minimal gap.

[0011] The invention, however, avoids a situation where, during operation of the arrangement, an area of ​​greatest curvature of the screw meets an area of ​​greatest curvature of the coil simultaneously, with only the minimal gap being formed between the two areas of greatest curvature.

[0012] In an advantageous embodiment of the arrangement, both the screw and the spool are rotatable relative to the axis of rotation, with the spool in particular being rotatable in the opposite direction to the screw. The resulting increased relative speed between the screw and the spool improves the kneading action and consequently the delamination of the fiber material. In a further advantageous embodiment of the arrangement, the screw contour and / or the spool contour is designed as a cycloid, in particular as a hypocycloid or hypotrochoid.

[0013] A cycloid is the path described by a point on the circumference of a circle when that circle rolls along a guiding curve.

[0014] A trochoid is the path if the guide curve is a circle, where the point under consideration lies either outside or inside the rolling circle.

[0015] A hypocycloid is formed when the conduction curve is a circle and the rolling circle rolls inside the conduction curve.

[0016] A hypotrochoid is formed when the guiding curve is a circle, the rolling circle rolls inside the guiding curve, and the point under consideration lies outside or inside the rolling circle.

[0017] In particular, the worm or coil contour is designed as a closed curve.

[0018] Preferably, the screw or spool contour is designed as an elongated hypotrochoid with inflection points, as an elongated hypotrochoid with approximate straight lines, or as an elongated hypotrochoid without inflection points. Designing the screw or spool contour as a cycloid allows for a precise contour definition, which can be optimally and accurately realized within the framework of machine manufacturing. In particular, it has been found that cycloids, and especially hypocycloids or hypotrochoids, allow for particularly gentle delamination of the fiber material and, in particular, avoid cutting, i.e., fiber-shortening, processing.

[0019] In a further advantageous embodiment of the arrangement, the screw contour and / or the spool contour is designed as a polygon. A polygon is defined as a multi-sided figure formed by a closed polygonal segment, wherein the closed polygonal segment includes vertices and segments connecting the vertices. Vertices themselves represent areas of greatest curvature. Preferably, the vertices are chamfered or rounded, with the rounded vertex still representing an area of ​​greatest curvature. Manufacturing contours designed as polygons is optimally achievable within the framework of machine production. This also results in the advantageous delamination of the fiber material while avoiding simultaneous fiber shortening.

[0020] In a preferred embodiment of the arrangement, the screw contour or the coil contour each comprises first sections and second sections. The first sections are tangent to or in contact with the inner envelope of the screw or the inner envelope of the coil, respectively. The second sections are tangent to or in contact with the outer envelope of the screw or the outer envelope of the coil, respectively. The first sections have a lesser curvature, in particular a lesser curvature than the respective envelopes. The second sections comprise the areas of greatest curvature and, in the case of a polygonal contour, are formed as corners. Advantageously, this avoids the situation where, during operation of the arrangement, a second section of the screw simultaneously collides with a second section of the coil, resulting in only a minimal gap between the second sections.Rather, in the operation of the arrangement, the minimum gap is formed when a second section of the screw, i.e., an area of ​​greatest curvature, meets a first section of the coil, i.e., an area of ​​lesser curvature, which in particular allows the advantageous delamination of the fiber material while avoiding fiber shortening of the fiber material.

[0021] In a particularly advantageous embodiment of the arrangement, the screw contour or the coil contour is formed from the first and second sections, the number of first and second sections determining the respective order of the screw contour or coil contour. Preferably, the order of the screw contour or coil contour is less than 20, and particularly preferably less than 13. For example, with a coil diameter of approximately 400 mm, an order of 5-7 is preferred; with a coil diameter of 600 mm, an order of 10; and with a coil diameter of 800 mm, an order of 12-13. An advantageous kneading effect can be achieved by appropriately selecting the order. In a particularly advantageous arrangement, the order of the screw contour differs from the order of the coil contour. Particularly preferably, the order of the screw contour is lower than the order of the coil contour.For example, the order of the worm gear can be 5 and the order of the coil 6. This has a beneficial effect on the torque development during one revolution of the worm gear in the coil. If the same order N is chosen for the coil and the worm gear, all N minimum gaps are engaged simultaneously. This directly results in torque peaks for the worm gear drive. By choosing different orders, however, it is avoided that all minimum gaps are engaged simultaneously, resulting in a smoother torque curve.

[0022] In an advantageous embodiment of the arrangement, the coil and the screw are cylindrical around the axis of rotation. This means that the coil contour has been imprinted onto a substantially cylindrical coil, or the screw contour has been imprinted onto a substantially cylindrical screw.

[0023] In an equally advantageous embodiment of the arrangement, the spool and the screw are conically shaped around the axis of rotation, with the opening angle of the cone preferably being less than or equal to 90° and particularly preferably less than or equal to 30°. The screw and the spool are essentially conical in shape, with the respective contour imprinted on the cone. The conical shape of the screw and the spool is particularly advantageous in combination with an arrangement in which the screw and the spool are movable relative to each other in the direction of the axis of rotation. By moving the conical screw and the conical spool in the direction of the axis of rotation, the size of the gap between the screw and the spool can be influenced, thus allowing direct control over the intensity of delamination of the fiber material.

[0024] In an equally advantageous embodiment of the arrangement, the surface of the screw and / or the inner surface of the spool is formed by twisting the screw contour or twisting the spool contour about the axis of rotation while simultaneously displacing it along the axis of rotation. This results in a respective helix angle to the axis of rotation of preferably less than or equal to 30°. Due to the rotation of the respective contour along the axis of rotation, the helix angle can be identified in a top view as the angle between the axis of rotation and the twisted contour. Designing the screw and / or the spool with a helix angle allows a conveying or retarding effect to be exerted on the fiber material guided through the arrangement.If the helix angle is selected such that, for a given conveying direction and screw rotation, a conveying effect on the fiber is achieved, this advantageously allows for a loosening of the conveyed fiber, while also preventing clogging within the assembly. Conversely, if the helix angle is selected such that, for a given conveying direction and screw rotation, a backflow effect on the fiber is achieved, this advantageously allows for an increased kneading effect and thus delamination of the fiber. In a particularly advantageous embodiment of the assembly, the twist of the screw contour occurs in the opposite direction to the twist of the spool contour. This allows for a particularly uniform kneading effect.

[0025] The invention will now be described using the drawings as an example.

[0026] Fig. 1 shows a compression screw comprising the arrangement according to the invention. Fig. 2 shows a detail from Fig. 1 and in particular the arrangement according to the invention.

[0027] Fig. 3 shows the arrangement according to the invention.

[0028] Fig. 4 shows a snail of the arrangement according to the invention.

[0029] Fig. 5 shows another compression screw according to the invention.

[0030] Fig. 1 shows a compression screw comprising the arrangement according to the invention, wherein the compression screw 17 can be configured as a maceration screw or a plugging screw. The compression screw 17 comprises a screw with a helix, the screw being rotatable about the axis of rotation 4. The fibrous material is processed between a housing and the screw. The housing is free of a helix and has a substantially circular contour. The screw is supported on one side, i.e., cantilevered, in the compression screw, with an inlet arranged between an outlet and the bearing. In Fig. 1, the arrangement 1 according to the invention is directly connected to the compression screw, the arrangement 1 being positioned between the outlet and the compression screw. The screw 2 of the arrangement and the screw of the compression screw are connected, resulting in a multi-part screw in this example.The housing of the arrangement comprises the coil 3 of the arrangement and is connected to the housing of the compression screw, so that the resulting housing is also multi-part. The screw 2 of the arrangement is arranged inside the coil 3 and is rotatable relative to the coil 3 about the axis of rotation 4. Neither the screw 2 nor the coil 3 of the arrangement 1 according to the invention has a helix.

[0031] Fig. 2 shows a detail from Fig. 1 and, in particular, the arrangement according to the invention. It is clearly visible that the screw is free of a helix and has a screw contour according to the invention. It is also evident that the surface of the screw is formed by a twist of the screw contour about the axis of rotation while simultaneously shifting it along the axis of rotation. In Fig. 2, the fibrous material is conveyed from left to right. Assuming a viewing direction in the conveying direction and a screw rotating counterclockwise in that direction, a backflow effect on the fibrous material would result, corresponding to the helix angle shown in Fig. 2.

[0032] Fig. 3 shows the arrangement according to the invention. The arrangement 1 is shown in a section normal to the axis of rotation 4, i.e., the axis of rotation 4 is shown as a projection or as a point. According to the invention, the worm 2 or the coil 3 has a worm contour 5 or a coil contour 6, respectively. The worm contour 5 is formed between an outer envelope 7 of the worm and an inner envelope 8 of the worm, and the coil contour 6 is formed between an outer envelope 9 of the coil and an inner envelope 10 of the coil. The envelopes 7, 8, 9, and 10 are circular.

[0033] According to the invention, the areas of greatest curvature 11 of the coil contour are arranged at or closer to the outer envelope 9 of the coil than at the inner envelope 10 of the coil. The coil 3 is concave in the areas of greatest curvature 11 when viewed from the inside. Similarly, according to the invention, the areas of greatest curvature 12 of the screw contour are arranged at or closer to the outer envelope 7 of the screw than at the inner envelope 8 of the screw. The screw is convex in the areas of greatest curvature 12 when viewed from the outside. A gap is formed between the screw 2 and the coil 3, the gap having a height that varies around the circumference as a result of the rotation of the screw 2. According to the invention, the minimum gap, i.e., the minimum gap height between coil 3 and screw 2, is then given when the area of ​​greatest curvature 12 of the screw contour meets an area of ​​the coil 13 with less curvature, i.e.between the two areas of greatest curvature 11 of the coil contour. This ensures that the fiber material is not subjected to a cutting action despite the minimal gap height.

[0034] Fig. 4 shows a screw of the arrangement according to the invention. The surface of the screw 2 was formed by a rotation of the screw contour 5 about the axis of rotation 4 while simultaneously displacing it along the axis of rotation 4. In Fig. 4, this is shown in particular as the rotation and displacement of the areas of greatest curvature 12 of the screw contour, or of the second sections 14. The helix angle 16 thus formed with respect to the axis of rotation 4 is also shown. Fig. 5 shows a compression screw 17, wherein more than one arrangement 1 according to the invention is connected to the compression screw 17. Strictly speaking, only the screw of the compression screw 17 and the screw 2 of the arrangement 1 are shown in Fig. 5. In particular, a first screw 2 of a first arrangement 1 according to the invention is arranged between two screws of the compression screw.Furthermore, a second screw 2 of a second arrangement 1 according to the invention is arranged at the outlet of the compression screw 17. The first screw 2 of the first arrangement 1 according to the invention, shown on the left in Fig. 5, is cylindrical about the axis of rotation 4, whereas the second screw 2 of the second arrangement 1 according to the invention, shown on the right in Fig. 5, is conical about the axis of rotation 4. The screw 2 shown in Fig. 5 is designed in particular for bearing on both sides in a compression screw 17, with bearings arranged in the inlet area and in the outlet area.

[0035] The present invention offers numerous advantages. The fiber material treated with an arrangement according to the invention allows for improved, faster, and therefore more effective absorption of liquids, chemicals, etc. The liquid or chemicals can be added, for example, in the area of ​​the spool or in a downstream device. Furthermore, in subsequent process steps—e.g., in a cooker, refiner, etc.—further processing of the isolated fibers is possible with lower energy consumption. In general, improved delamination of the fiber material, or a particularly gentle separation of the fibers, is enabled, and in particular, a cutting treatment of the fiber material is avoided.

[0036] Reference sign

[0037] 1. Delamination arrangement

[0038] 2 snails

[0039] 3 coil

[0040] 4 Rotation axis 5 Screw contour

[0041] 6 Coil contour

[0042] 7 outer shells of the snail

[0043] 8 inner envelopes of the worm gear 9 outer envelopes of the coil

[0044] 10 inner envelopes of the coil

[0045] 11 areas of greatest curvature of the coil contour

[0046] 12 areas of greatest curvature of the snail contour

[0047] 13 First Section 14 Second Section

[0048] 15 opening angles

[0049] 16 Twist angles

[0050] 17 Compression screw

Claims

Patent claims 1. Compression screw (17), in particular maceration screw or plugging screw, comprising a screw of the compression screw (17) and an arrangement (1) for delaminating a fibrous material, in particular lignocellulose, the arrangement (1) comprising a screw (2) and a spool (3), wherein the screw (2) is connected to the screw of the compression screw and the screw (2) is rotatable relative to the spool (3) about an axis of rotation (4), the screw (2) or the spool (3) having a screw contour (5) or a spool contour (6) in a plane normal to the axis of rotation (4), wherein the screw contour (5) is formed between an outer envelope (7) of the screw and an inner envelope (8) of the screw and the spool contour (6) is formed between an outer envelope (9) of the spool and an inner envelope (10) of the spool, characterized in that the areas of greatest curvature (11) the coil contour orare located closer to the outer envelope (9) of the coil than to the inner envelope (10) of the coil, and the areas of greatest curvature (12) of the worm contour are located at or closer to the outer envelope (7) of the worm than to the inner envelope (8) of the worm.

2. Arrangement (1) according to claim 1, wherein the screw contour (5) and / or the coil contour (6) are designed as cycloids, in particular as hypocycloids or as hypotrochoids.

3. Arrangement (1) according to claim 1, wherein the screw contour (5) and / or the coil contour (6) are formed as a polygon.

4. Arrangement (1) according to any one of claims 1 to 3, wherein the screw contour (5) or the coil contour (6) each comprise first sections (13) and second sections (14), the first sections (13) of each comprising the inner envelope (8) of the screw or the inner envelope (10) of the coil, respectively, and the second sections (14) of each comprising the outer envelope (7) of the screw or the outer envelope (9) of the coil. tangent or touching, with the second sections (14) encompassing the regions (11 ,12) of greatest curvature.

5. Arrangement (1) according to claim 4, wherein the screw contour (5) or the coil contour (6) is formed from the first sections (13) and the second sections (14), and the number of first sections (13) or second sections (14) determines the respective order of the screw contour (5) or order of the coil contour (6).

6. Arrangement (1) according to claim 5, wherein the order of the screw contour (5) or order of the coil contour (6) is less than 20, preferably less than 13.

7. Arrangement (1) according to claim 5 or 6, wherein the order of the screw contour (5) is different from the order of the coil contour (6), wherein preferably the order of the screw contour (5) is smaller than the order of the coil contour (6).

8. Arrangement (1) according to one of claims 1 to 7, wherein the coil (3) and the worm (2) are cylindrical around the axis of rotation (4).

9. Arrangement (1) according to one of claims 1 to 7, wherein the coil (3) and the worm (2) are conically formed around the axis of rotation (4), wherein the opening angle (15) of the cone is preferably less than or equal to 90° and particularly preferably less than or equal to 30°.

10. Arrangement (1) according to one of claims 1 to 9, wherein the surface of the screw (2) and / or the inner surface of the coil (3) is formed by a rotation of the screw contour (5) or rotation of the coil contour (6) about the axis of rotation (4) while simultaneously displacing it along the axis of rotation (4), wherein a respective twist angle (16) of preferably less than or equal to 30° is formed with respect to the axis of rotation (4).

11. Arrangement (1) according to claim 10, wherein the rotation of the worm contour (5) is opposite to the rotation of the coil contour (6).

12. Arrangement (1) according to one of claims 1 to 11, wherein the worm (2) and the coil (3) are movable relative to each other in the direction of the axis of rotation (4).

13. Arrangement (1) according to any one of claims 1 to 12, wherein the respective envelopes (7, 8, 9, 10) are circular and have a respective diameter, wherein the diameter of the inner envelope (8) of the screw is preferably between 100 mm and 950 mm, and the The diameter of the outer envelope (9) of the coil is preferably between 130 mm and 1000 mm.

14. Arrangement (1) according to claim 13, wherein a first difference is formed from the diameter of the outer envelope (9) of the coil minus the diameter of the inner envelope (8) of the screw, a second The difference is formed from the diameter of the inner envelope (10) of the coil minus the diameter of the outer envelope (7) of the screw, where the quotient of the first difference and the second difference denotes a kneading effect, and the kneading effect is in a range greater than 1 to 5.

15. Arrangement (1) according to one of claims 1 to 14, wherein both the screw (2) and the coil (3) are rotatable relative to the axis of rotation (4) and wherein the coil (3) is in particular rotatable opposite to the screw (2).

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