Device for producing pellets

Abstract

Proposed is a device for producing pellets, comprising: a machine frame (1); a hollow outer cylinder (2) which is mounted in said machine frame and has a first axis of rotation (5); and an inner cylinder (3) which is arranged in the outer cylinder (2) and has a second axis of rotation (6); wherein: a wedge-shaped gap (4) is formed between an inner surface of the outer cylinder (2) and an outer surface of the inner cylinder (3); the outer cylinder (3) and / or the inner cylinder (3) has radial holes (16) for pressing through material; and a pivot arm (7) is arranged on each of the two sides next to the inner cylinder (3), on which pivot arms the inner cylinder (3) is rotatably mounted. Each pivot arm (7) is mounted on the machine frame (1) on a pivot bearing having a pivot axis (10), and is pivotable about the pivot bearing (10) by means of at least two drives (11a, 11b, 11c).

Description

[0001] DEVICE FOR PRODUCING PELLETS

[0002] The invention relates to a device for producing pellets, with a machine frame, a hollow outer cylinder mounted therein with a first axis of rotation and an inner cylinder arranged in the outer cylinder with a second axis of rotation, wherein a wedge-shaped gap is formed between an inner surface of the outer cylinder and an outer surface of the inner cylinder, wherein the outer cylinder and / or the inner cylinder has radial holes for pressing material through, and wherein a pivot arm is arranged on either side next to the inner cylinder, on which pivot arm the inner cylinder is rotatably mounted, wherein each pivot arm is mounted on a pivot bearing with a pivot axis on the machine frame.

[0003] Such a device is known from WO 2018 / 104457 A1.

[0004] Pressing shredded material into pellet form, also known as pelletizing, offers numerous advantages, such as increased bulk density, standardized material size, and the avoidance of segregation of different raw materials. In the processing of fuel, feed, or bedding, pellets made from shredded biomass, such as wood pellets, straw pellets, or residual pellets, have gained importance in recent decades and now occupy an important position.

[0005] Since the material to be compressed, especially shredded biomass, can vary greatly in nature, particularly with regard to material properties and the size of the shredded material, it is advantageous to be able to adapt the pressing force to specific requirements. Some materials that are difficult to pelletize and therefore require high pressing forces can result in high mechanical stress and thus in mechanical deformation of the device, which leads not only to faster material fatigue but also to increased wear of the device.

[0006] The invention is therefore based on the object of providing a device of the type mentioned at the outset which is better adapted in particular for higher loads.

[0007] This object is achieved according to the invention with a device which has the features of claim 1.

[0008] Preferred and advantageous embodiments of the invention are the subject of the dependent claims.

[0009] According to the invention, at least two drives are connected to each pivot arm, allowing the respective pivot arm to pivot about the pivot bearing. This not only allows the force applied by the drives to be better distributed among the pivot arms, but also makes it possible to generate higher pressing forces for materials that are difficult to pelletize.

[0010] It is particularly preferred in the invention if three drives are connected to each swivel arm, as this allows the aforementioned advantages to be realized even more effectively. If necessary, more than three drives can be used.

[0011] A practical and advantageous embodiment of the invention is characterized in that all drives are arranged on one side of the swivel arm. In this case, they can be located next to each other and both the machine frame and the swivel arms can preferably be reinforced only in this area. Each drive can, in a particularly preferred

[0012] According to an embodiment of the invention, a force, preferably a tensile force, is generated along a force vector.

[0013] In this context, it is further preferred in the invention if the force vectors of the drives are arranged parallel to one another. This leads to a uniform and, with regard to the position of the inner cylinder relative to the outer cylinder, optimal force transmission into the pivot arms.

[0014] In the invention, it is further preferred if the force vectors of all drives are located on the side of the inner cylinder's rotational axis facing away from the pivot axis. Even if this is not absolutely necessary, it is nevertheless advantageous because it provides all drives with a longer lever arm than the lever arm of the inner cylinder's rotational axis, which is advantageous in terms of force distribution.

[0015] Furthermore, in the present invention, it is preferred that the pivot axis of the pivot bearings and the points of engagement of the drives on the pivot arms lie essentially on one line, and that the force vectors are aligned essentially at right angles to this line. This also leads to optimal transmission of the forces generated by the drives into the pivot arms and onto the inner cylinder.

[0016] Hydraulic cylinders are preferred as the drive units in this invention, as these can be used to generate high forces in a proven manner. However, other drive types, such as spindle drives, are also conceivable.

[0017] Within the scope of the invention, an embodiment is particularly preferred in which each pivot arm is mounted in the pivot bearing by means of an eccentric shaft. This allows the distance between the rotational axes of the outer and inner cylinders, and thus the gap width, to be very precisely reduced or increased and, if necessary and depending on the position of the eccentric shaft, also adjusted transversely to the force vectors.

[0018] In a preferred development of this embodiment, the eccentric shaft has a first section with a first axis and a second section with a second axis at both ends. The second axis is parallel to the first axis, i.e. it is at a distance from it, whereby the second section is eccentric to the first section. The eccentric shaft is rotatably mounted with the first section in the machine frame and with the second section in the respective swivel arm. By turning the eccentric shaft, the position of the inner cylinder in the outer cylinder can be adjusted.

[0019] In a particularly advantageous embodiment, the inner cylinder is hollow and has substantially radially aligned holes.

[0020] Preferably, the inner cylinder is driven by a drive via a gear mechanism, and the material, in particular the shredded biomass, is introduced into the wedge-shaped, tapered gap and pressed through the holes into an interior of the inner cylinder and out of the outer cylinder. The material is thereby compressed and formed into pellets.

[0021] Further details, features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, which do not limit the scope of protection, with reference to the attached drawings. Therein: Fig. 1 is a roughly schematic, isometric view of a device according to the invention,

[0022] Fig. 2 is a side view of the device of Fig. 1, Fig. 3 is an isometric view of an alternative embodiment of the invention, and

[0023] Fig. 4 is a side view of the device of Fig. 3.

[0024] The drawings illustrate embodiments of devices according to the invention, which, however, are only examples and, apart from the inventive features as defined in the claims, many components may also be implemented differently within the scope of the present invention without this requiring special mention below. In particular, components and features described in the various embodiments of the invention may be combined with one another in any way, even without this being expressly mentioned in every possible case.

[0025] Figures 1 and 2 show a roughly schematic view of a first embodiment of an apparatus according to the invention for producing pellets, in particular from comminuted biomass, in an isometric view and in elevation.

[0026] A hollow outer cylinder 2 is rotatably mounted in a machine frame 1, and a hollow inner cylinder 3 is arranged in the hollow outer cylinder 2. A wedge-shaped gap 4 is formed between an inner surface of the outer cylinder 2 and an outer surface of the inner cylinder 3.

[0027] The outer cylinder 2 has a rotation axis 5 and the inner cylinder has a rotation axis 6 which are parallel to each other.

[0028] On both sides of the outer cylinder 2 and the inner cylinder 3, pivot arms 7 are movably mounted on the machine frame 1. The rotation axis 6 of the inner cylinder 3 lies approximately in the upper central region of the pivot arms 7.

[0029] Each pivot arm 7 has two ends 8 and 9. One end 8 of the pivot arms 7 is mounted on the machine frame 1 around a pivot bearing, the pivot bearings having a common pivot axis 10.

[0030] Towards the other end 9 of each swivel arm 7, in the illustrated embodiment of the invention, three drives 11a, 11b, 11c in the form of hydraulic cylinders are arranged, which are mounted with one end, preferably the cylinder 12a, 12b, 12c, on the machine frame 1 and with the other end, preferably the piston rod 13a, 13b, 13c, on the respective swivel arm 5.

[0031] The force that the drives 11a, 11b, 11c apply to the respective swivel arm 7 has force vectors 14a, 14b, 14c, which are preferably (but not necessarily) parallel to one another and lead past the rotation axis 6 on the side facing away from the swivel axis 10.

[0032] In the embodiment of the invention shown in Figs. 1 and 2, the attack points, more precisely the bearing axes 15a, 15b, 15c, with which the piston rods 13a, 13b, 13c are mounted on the respective pivot arm 7, lie in a line 16, whereas the pivot axis 10 of the pivot arms 7 is at a distance from this line 16.

[0033] In the preferred embodiment of Figs. 3 and 4, the pivot axis 10 also lies on this line 16.

[0034] The force vectors 14a, 14b, 14c are preferably at right angles to the line 16. This configuration has the advantage of enabling optimal force introduction of all components and optimal running or optimal positioning of the inner cylinder 3 in the outer cylinder 2.

[0035] However, a distance of one or more of the axes 10, 15a, 15b, 15c from the line 16 and a deviation of the angle between the line 16 and the force vectors 14a, 14b, 14c is also possible without deviating from the core of the invention and without having to accept considerable disadvantages compared to the optimal solution.

[0036] 1 to 4, all drives 11a, 11b, 11c are located on one side (the underside in the drawings) of the pivot arms 7. However, it would also be possible for at least one of the drives 11a, 11b, 11c to be arranged at a different location, e.g. the top side, of the pivot arms 7, if this is advantageous for reasons of space or mechanical reasons. Likewise, it is also possible for at least one of the drives, for example drive 11a, to be located on the side of the axis of rotation 6 of the inner cylinder 3 facing the pivot axis 10, or for the force vector 14a of this drive 11a to pass the axis of rotation 6 on the side facing the pivot axis 10.

[0037] The pivot axis 10 can be formed by an eccentric shaft 17 in order to adjust the position of the pivot arms 7 and thus the position of the inner cylinder 3 within the outer cylinder 2. This also allows the position and size of the gap 4 to be influenced.

[0038] As can be seen in Fig. 4, the eccentric shaft 17 has two parallel axes 18, 19, the eccentric shaft 17 being mounted at both ends with a first section, which defines the axis 18, in the machine frame, and with a second section, which defines the axis 19, in the pivot arms 7. By rotating the eccentric shaft 17, either manually or with the aid of a drive, for example a three-phase motor, the ends 8 of the pivot arms 7 are raised or lowered and at the same time moved laterally. By means of the hydraulic cylinders 12a, 12b, 12c and the connections thus formed between the pivot arms 7 and the machine frame 1, each of which has two degrees of freedom, the pivot arms 7 are able to carry out the displacements associated with the rotating of the eccentric shaft 17.

[0039] The outer cylinder 2 is mounted on both sides in the machine frame 1 via roller bearings and the inner cylinder 3 is rotatably mounted in the swivel arms 5 via a roller bearing.

[0040] The wedge-shaped gap 4, which is adjustable as described above, has a maximum width in the upper central region and a minimum width in the lower central region. Although this is an optimal position for the gap 4 in the embodiments of the invention shown in the drawings, the minimum and maximum gap regions can also be rotated by several degrees in one direction or the other about the axis 5.

[0041] The rotary drive of the inner cylinder 3 can be designed as shown and described in WO 2018 / 104457 A1 and have a clutch that connects the inner cylinder 3 to a gear 20, which can be a planetary gear, for example. The gear can be connected via a further clutch to a drive shaft, e.g. a cardan shaft, which is driven by a main drive, whereby the inner cylinder 3 is set in rotation. The outer cylinder 2 rotates in the same direction as the inner cylinder 3 due to the frictional forces that arise between the cylinders 2, 3 and the material pressed together therebetween. The material is introduced into the upper region of the wedge-shaped gap 4 through a filling opening 20 between the cylinders 2, 3 and moved by the rotation of the latter to the lower region of the gap 4 into the region of the minimum width.

[0042] Both the outer cylinder 2 and the inner cylinder 3 can have substantially radially aligned holes through which the material, in particular shredded biomass, is pressed and formed into pellets when the inner cylinder 3 and outer cylinder 2 rotate in the region of the minimum width of the gap 4.

[0043] The pellets formed by the outer cylinder 2 fall out of the device at the bottom, for example directly into a

[0044] On a collecting container or on a conveyor system. The pellets formed by the inner cylinder 2 collect inside the inner cylinder 2 and, since the inner cylinder 2 can be open on one side, can fall out of the device or be removed laterally.

[0045] Reference symbol list:

[0046] 1 machine frame

[0047] 2 outer cylinders

[0048] 3 inner cylinders

[0049] 4 gap

[0050] 5 axis of rotation

[0051] 6 axis of rotation

[0052] 7 swivel arms

[0053] 8 End

[0054] 9 End

[0055] 10 Swivel axis

[0056] 11a, 11b, 11c Drives

[0057] 12a, 12b, 12c cylinders

[0058] 13a, 13b, 13c piston rods

[0059] 14a, 14b, 14c Force vectors

[0060] 15a, 15b, 15c bearing axes

[0061] 16 Line

[0062] 17 Eccentric shaft

[0063] 18 Axis

[0064] 19 Axis

[0065] 20 Filling opening

Claims

Claims:

1. Device for producing pellets, comprising a machine frame (1), a hollow outer cylinder (2) mounted therein with a first axis of rotation (5) and an inner cylinder (3) arranged in the outer cylinder (2) with a second axis of rotation (6), wherein a wedge-shaped gap (4) is formed between an inner surface of the outer cylinder (2) and an outer surface of the inner cylinder (3), wherein the outer cylinder (3) and / or the inner cylinder (3) has radial holes for pressing material through, and wherein a pivot arm (7) is arranged on each side next to the inner cylinder (3), on which pivot arm the inner cylinder (3) is rotatably mounted, wherein each pivot arm (7) is mounted on a pivot bearing with a pivot axis (10) on the machine frame (1), characterized in that each pivot arm (7) is pivotable about the pivot bearing by means of a drive (11a, 11b, 11c), and that with each pivot arm (7) at least two drives (11a, 11b, 11c) are connected,with which the respective swivel arm (7) can be swivelled around the swivel bearing., 2. Device according to claim 1, characterized in that with each swivel arm (7) three or more than three drives (11a, 11b, 11c) are connected.

3. Device according to claim 1 or 2, characterized in that all drives (11a, 11b, 11c) are arranged on one side of the pivot arm (7).

4. Device according to one of claims 1 to 3, characterized in that the force of each drive (11a, 11b, 11c) acts along a force vector (14a, 14b, 14c).

5. Device according to claim 4, characterized in that the force vectors (14a, 14b, 14c) of the drives (11a, 11b, 11c) are arranged parallel to one another.

6. Device according to one of claims 1 to 5, characterized in that all drives (11a, 11b, 11c) are arranged on one side of the pivot arm (7).

7. Device according to one of claims 1 to 6, characterized in that the drives (11a, 11b, 11c) are hydraulic cylinders.

8. Device according to one of claims 4 to 7, characterized in that the force vectors (14a, 14b, 14c) of all drives (11a, 11b, 11c) lie on the side of the axis of rotation (6) of the inner cylinder (3) facing away from the pivot axis (10).

9. Device according to one of claims 4 to 8, characterized in that pivot axes (10) of the pivot bearings and the points of application of the drives (11a, 11b, 11c) on the pivot arms (7) lie substantially on a line (16), and that the force vectors (14a, 14b, 14c) are aligned substantially at right angles to this line (16).

10. Device according to one of claims 1 to 9, characterized in that each pivot arm (7) is mounted in the pivot bearing by means of an eccentric shaft (17).

11. Device according to claim 10, characterized in that the eccentric shaft (17) has at both ends a first section with a first axis (18) and a second section with a second axis (19), that the first axis (18) is parallel to the second axis (19), and that the eccentric shaft (17) is rotatably mounted with the first section in the machine frame (1) and with the second section in the respective swivel arm (7).

12. Device according to one of claims 1 to 11, characterized in that the inner cylinder (3) is mounted on the pivot arms (7) via bearings, in particular rolling bearings, preferably spherical roller bearings, and / or that the outer cylinder (2) is mounted on both sides on the machine frame (1) via bearings, in particular rolling bearings, preferably spherical roller bearings.

13. Device according to one of claims 1 to 12, characterized in that the inner cylinder (3) is hollow.

14. Device according to one of claims 1 to 13, characterized in that the inner cylinder (3) is connected on at least one side to a main drive via a gear.

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