Pellet press for the production of pellets with a flat die and a breaking device designed as a breaking plate.

Abstract

Pellet press (100) for producing pellets by pressing a material using extrusion granulation, wherein the pellet press (100) has a flat die (10) with a plurality of press channels (11), wherein the pellet press further comprises at least one roller (12) running or retractable on the flat die (10), wherein the pellet press (100) has a break-off device (13) rotatable relative to the flat die (10) with a contact surface (14) oriented towards the flat die (10) and spaced apart from the flat die (10), characterized in that the break-off device (13) is resiliently mounted on a support (15) below an exit side (16) of the flat die (10).

Description

Technical field

[0001] The invention relates to a pellet press for producing pellets by pressing a material using extrusion granulation, wherein the pellet press has a flat die with a plurality of press channels, wherein the pellet press further has at least one roller running or retractable on the flat die, wherein the pellet press has a breaking device rotatable relative to the flat die with a contact surface oriented towards the flat die and spaced apart from the flat die. State of the art

[0002] Pellet presses are used to compress raw material into pellets. Rollers typically force the material through press channels, causing it to emerge in strands of pellets. Blades positioned away from the exit side of the press channels then break these strands, producing pellets of varying lengths.

[0003] Pelletizing is also called extrusion granulation. Essentially, two different types of pellet presses are known in the prior art: pellet presses with flat dies and ring dies.

[0004] In a pellet press with a flat die, the material is applied from above onto a perforated disc, namely a die, and forced through the press channels in the die by multiple passes of rollers. This creates numerous strands, which are broken off by contact with the rotating knife located below the perforated disc. The contact of the knife with the pellet strands results in a rough breakage of the strands, producing pellets of slightly varying lengths. The distance between the knife and the die defines only the median length distribution of the pellets.

[0005] In DE 10 2013 022 395 B3 a pellet press with ring die is described.

[0006] DE 20 2018 000 161 U1 shows a pellet press with a flat die and a breaking device arranged below the flat die.

[0007] AT 519 145 A1 and CN 1 08 501 437 describe devices for cutting the material strands emerging from a flat die to length in order to obtain pellets. In this process, the respective material strand is cut laterally by rotating knife-like components. Description of the invention: Problem, solution, advantages

[0008] The object of the present invention is to improve a previously described pellet press with a flat die in such a way that the variance in the length distribution of the pellets or the pressed pieces is significantly reduced, so that the pellets are to a significant extent of the same length.

[0009] According to the invention, a pellet press for the production of pellets by pressing a material by means of extrusion granulation is proposed, wherein the pellet press has a flat die with a plurality of press channels, wherein the pellet press further has at least one roller running or retractable on the flat die, wherein the pellet press has a breaking device rotatable relative to the flat die with a contact surface oriented towards the flat die and spaced apart from the flat die.

[0010] According to the invention, the breaking device is spring-mounted on a support below an exit side of the flat die.

[0011] Because the breaking device is spring-mounted on a support below the flat die and has a contact surface, the pellet strands are broken upon contact with the contact surface of the breaking device. In the prior art, a breaking device based on a knife is typically used, whereby the pellet strands are broken by the lateral impact of the knife. In this process, the knife-shaped breaking device rotates below the flat die, producing pellets with a relatively large variance in their length.

[0012] The flat breaking device, or the breaking device with a contact surface, whereby the pellet strands are broken upon impact by contact with the contact surface and not by lateral impact of the knife, significantly reduces the variance in terms of pellet length.

[0013] According to the invention, the pellet press has a flat die and not a ring die. The flat die is designed as a type of perforated disc with press channels. The at least one roller is rotatably arranged relative to the flat die. That is, the at least one roller is rotated about its own axis, so that the material is forced through the press channels from above. Preferably, several rollers are provided, for example, three or four rollers.

[0014] The material is fed into the pellet press and preferably applied gravimetrically to the top of the flat die. Multiple passes in a roller mill force the material through the press channels, producing small strands.

[0015] The breaking device has a contact surface onto which the strands strike and break in a controlled manner, thus preventing them from being broken by a lateral impact of a knife. In the solution according to the invention, the length of the pellets is therefore limited by the distance between the underside of the flat die (i.e., its exit side) and the contact surface of the breaking device. In the prior art, the distance between the flat die and the knife merely represents the median of the pellet length distribution and does not limit the maximum length.

[0016] According to the invention, the breaking device rotates relative to the flat die, whereby the centrifugal force carries the pellets outwards after or during breaking. In the prior art, the pellets typically fall between the blades and are then conveyed out of the pellet press by means of an ejection disc arranged below the blades.

[0017] To improve accuracy and thus further reduce the variance in the length distribution of the pellets, the breaking device is, according to the invention, spring-mounted on a support below the exit side of the flat die. The support is arranged below, i.e., spaced from, the underside or exit side of the flat die, around a central axis of the pellet press and can be rotated, for example, by the rotatable axle (vertical shaft) of the pellet press together with the rollers. The support could be designed as a kind of pedestal or as an ejection disc below the flat die.

[0018] The spring-loaded mounting reduces the mechanical stress when the pellet strands strike the breaker or its contact surface. Under high pressure, the spring-loaded mounting allows the breaker to yield slightly.

[0019] Preferably, the breaking device is plate-shaped and / or ring-shaped, in particular disc-shaped. The breaking device, especially the disc-shaped one, can be arranged around the axis of the pellet press with a central opening. The breaking device is not directly attached to the axis itself, but is supported on the base below the flat die. Because the breaking device is plate-shaped and / or ring-shaped, in particular disc-shaped, it has, unlike the knives known from the prior art, a contact surface that covers a large area of ​​the press channels.

[0020] The snap-off device is preferably designed in multiple parts, with the contact surface of the snap-off device being formed by adjacent surfaces of individual segments of the snap-off device. The snap-off device thus preferably consists of several segments arranged side by side, in particular in a ring-shaped arrangement.

[0021] Preferably, the breaking device has between two and ten segments, more preferably between four and eight segments. The segments are more preferably designed as circular segments.

[0022] Furthermore, it is preferably provided that the individual segments of the break-off device are mounted separately on the support, in particular by means of springs. This means that each individual segment is mounted on the support, in particular by means of springs, on its own. Thus, the segments in areas of higher stress can yield more than other segments, thereby improving the mechanical load and thus the service life and, in turn, the precision of the device.

[0023] Furthermore, it is preferably provided that the contact surface of the breaking device has a surface structure designed to promote breaking and / or ejection. For example, a rough surface or a surface with edges can favor controlled breaking of the strands. Additionally, the shape of the contact surface could serve to convey the broken pellets outwards, thus promoting ejection immediately after breaking. Brief description of the drawings

[0024] The invention is explained below by way of example using preferred embodiments. The schematic representations show: Fig. 1: A perspective view of the essential components of a pellet press, Fig. 2: A side view of the essential components of the pellet press, Fig. 3: a pellet press with a break-off device spring-mounted below the flat die, and Fig. 4: A top view of a break-off device of the pellet press. Preferred embodiments of the invention

[0025] Fig. Figure 1 schematically shows in perspective a pellet press 100 for the production of pellets by pressing a material by means of extrusion granulation, wherein the pellet press 100 has a flat die 10 with a plurality of press channels 11.

[0026] Roller rollers 12 are arranged above the flat die 10 and can run along the flat die 10. The roller rollers 12 press the material through the press channels 11 of the flat die 10.

[0027] Below and spaced apart from the flat die 10, a breaking device 13 is arranged, which is rotatable relative to the flat die 10. The breaking device 13 has a contact surface 14. When the pellet strands strike the contact surface 14 of the breaking device 13, the pellet strands are broken in a defined manner.

[0028] The breaking device 13 is mounted on a support 15 below the exit side 16 of the flat die 10.

[0029] Fig. Figure 2 shows a side view of the pellet press 100. Fig. 1. In Fig. Figure 2 again clearly shows the mounting of the break-off device 13 on the support 15 below the flat die 10.

[0030] In Fig. Figure 3 shows a spring-loaded mounting of the break-off device 13 on the support 15.

[0031] Fig. Figure 4 schematically shows a top view of a break-off device 13 consisting of several ring-shaped segments 17. The segments 17 can be individually mounted on the support 15 or, in particular, be spring-mounted. The mounting of the individual segments 17 of the break-off device 13 is shown in Fig. 4 are not shown for the sake of clarity. Reference symbol list 100 pellet press 10 flat die 11 press channels 12 roller rollers 13 Break-off device 14 Contact area 15th edition 16 Exit side of the flat die 17 segments of the break-off device

Claims

Pellet press (100) for producing pellets by pressing a material using extrusion granulation, wherein the pellet press (100) has a flat die (10) with a plurality of press channels (11), wherein the pellet press further comprises at least one roller (12) running or retractable on the flat die (10), wherein the pellet press (100) has a break-off device (13) rotatable relative to the flat die (10) with a contact surface (14) oriented towards the flat die (10) and spaced apart from the flat die (10), characterized in that the break-off device (13) is resiliently mounted on a support (15) below an exit side (16) of the flat die (10). Pellet press (100) according to claim 1, characterized in that the breaking device (13) is plate-shaped and / or ring-shaped, in particular plate-shaped. Pellet press (100) according to claim 1 or 2, characterized in that the breaking device (13) is designed in multiple parts, wherein the contact surface (14) of the breaking device (13) is formed by adjacent surfaces of individual segments (17) of the breaking device (13). Pellet press (100) according to claim 3, characterized in that the demolition device (13) has between 2 and 10 segments (17), preferably between 4 and 8 segments (17). Pellet press (100) according to one of the preceding claims, characterized in that the individual segments (17) of the breaking device are mounted separately on the support (15), in particular in a resilient manner. Pellet press (100) according to one of the preceding claims, characterized in that the contact surface (14) of the breaking device has a surface structure which is designed to promote breaking and / or ejection.

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