Device for producing pellets

Abstract

Device for producing pellets from renewable raw materials, in particular wood pellets, comprising a feed unit (1), a pelletizing device (3) and a discharge unit (2), characterized in that the feed unit (1) - has a mixer (4) in which raw material particles can be mixed by adding a liquid and / or an additive and - has a screw assembly (5) arranged below the mixer (4) through which the mixed raw material particles can be conveyed in a first direction and an opposite second direction, wherein the feed unit (1) and the discharge unit (2) form a common assembly which is arranged next to the pelletizing device (3), wherein the outlet (15) of the feed unit (1) and the inlet (18) of the discharge unit (2) are arranged on the same front side of the assembly.

Description

[0001] The invention relates to a device for producing pellets from renewable raw materials, in particular wood pellets, comprising a feeding unit, a pelletizing device and a discharge unit.

[0002] From Austrian patent AT 510 726 B1, a device for producing pellets from a renewable raw material is known, consisting as a unit of a feed unit, a pelletizing unit, and a discharge unit. The feed unit has a mixer, optionally a mill, a storage container, and a metering screw, by means of which raw material particles are pre-processed and then fed to the pelletizing unit. In the pelletizing unit, the raw material particles are compressed into pellets and then fed to the discharge unit, which is designed as a collection container. The known device has a compact design. However, it is not suitable for retrofitting existing pelletizing units.

[0003] From EP 0 193 666 A1, a screw assembly is known as part of a pelletizing device by means of which wood pellets are formed. For this purpose, the screw assembly is heated.

[0004] The object of the present invention is to further develop a device for producing pellets in such a way that a compact design is ensured in a simple manner, in particular ensuring the possibility of retrofitting existing pelleting equipment.

[0005] To solve the problem, the invention in conjunction with the preamble of claim 1 is characterized in that the feeding unit - has a mixer in which raw material particles can be mixed by adding a liquid and / or an additive and - has a screw arrangement located below the mixer, through which the mixed raw material particles can be conveyed in a first direction and an opposite second direction.

[0006] According to the invention, the feeding unit comprises a driven mixer and a screw conveyor. Raw material particles are mixed in the mixer with the addition of a liquid and / or an additive. The screw conveyor allows the mixed raw material particles to be transferred to a pelletizing unit in a space-saving and metered manner. The feeding unit has a compact design, with the screw conveyor located below the mixer.

[0007] According to a preferred embodiment of the invention, a lower screw of the screw assembly has an opening at the front of the feed unit, forming the outlet of the feed unit, for transferring the mixed raw material particles to the pelletizing unit. At the rear of the feed unit or screw assembly, a transfer section is provided connecting the lower screw to the upper screw of the screw assembly, so that the mixed raw material particles traverse twice the screw path before being transferred to the pelletizing unit. In this way, mixing and dosing of the mixed raw material particles can be carried out in a space-saving manner, with the throughput being adaptable to the requirements of the pelletizing unit.

[0008] According to a further development of the invention, the discharge unit is arranged vertically below the feed unit, so that the assembly thus formed is compact. The discharge unit includes means for cleaning and / or cooling the pellets. Advantageously, the assembly consisting of the feed and discharge units can be attached to conventional pelletizing equipment, with the inlet and outlet of this assembly being connected to the pelletizing equipment via standard connecting means.

[0009] Further advantages of the invention will become apparent from the further dependent claims.

[0010] An embodiment of the invention is explained in more detail below with reference to the drawings.

[0011] They show: Fig. 1. A perspective view of a construction unit consisting of a feed and discharge unit. Fig. 2 a front view of the assembly unit according to Fig. 1 and Fig. 3 a side view of the assembly unit according to Fig. 1, where a pelletizing device is schematically shown in the area of ​​a front of the assembly.

[0012] A device according to the invention for producing pellets is particularly suitable for producing wood pellets from renewable raw materials, especially from sawdust particles.

[0013] The in Fig. The device shown in Figure 3 essentially consists of a feed unit 1, a discharge unit 2 and a pelletizing device 3.

[0014] The pelletizing unit 3 can be designed as a conventional pelletizing plant in which wood pellets with a diameter in the range of 3mm to 20mm are formed by pressing.

[0015] The feed unit 1 essentially comprises a driven mixing drum 4 as a mixer and a twin screw arrangement 5 as a screw arrangement.

[0016] The mixing drum 4 has blades 6 which are continuously pivoted about a rotary axis A by means of a drive unit 7. The rotary axis A runs between a front wall 8 and a rear wall 9 of the feed unit 1. The drive unit 7 is designed as an electric motor which is attached to the front wall 8 of the feed unit 1 in line with the rotary axis A.

[0017] A diaphragm pump 10 is provided for supplying water (liquid) to the twin screw arrangement 5 so that the sawdust introduced via a removable cover 11 can be mixed into a sawdust mass.

[0018] The twin screw assembly 5 is arranged directly below the mixing drum 4 and consists of an upper first twin screw 5' and a second lower twin screw 5" arranged vertically below it. The sawdust mass is preferably transferred to the upper twin screw 5' in the area of ​​the front wall 8 of the feed unit 1, so that it is conveyed by the upper twin screw 5' towards the rear wall 9 of the feed unit 1 and then transferred by means of a transfer section 12 arranged at the rear 9 to the lower twin screw 5", by means of which the sawdust mass is conveyed back towards the front wall 8 of the feed unit 1. For this purpose, for example, the upper twin screw 5' is driven clockwise and the lower twin screw 5" counterclockwise by means of an electric motor 13.The conveying path of the sawdust mass through the twin screw arrangement 5 is approximately twice the length I of the respective twin screws 5', 5" or twice the distance between the front wall 8 and the rear wall 9 of the feed unit 1. The front wall 8 and the rear wall 9 are connected to each other via opposite side walls 20.

[0019] The lower twin screw 5" has an outlet opening 14 on the front wall 8 of the feed unit 1, which forms an outlet 15 of the feed unit 1. Via suitable connecting means, e.g. a discharge pipe 32, the outlet 15 of the feed unit 1 is connected to the pelletizing unit 3, so that the sawdust mass can be metered continuously according to direction 16 to the pelletizing unit 3.

[0020] The feed unit 1 also has a switching device 17 for switching on and off the electric motor 13 driving the twin screws 5', 5" or a speed controller.

[0021] According to an alternative embodiment not shown, the conveying path of the sawdust mass in the screw arrangement 5 can also be extended by providing three or more screws.

[0022] The discharge unit 2, located directly below the feed unit 1, has means for cleaning and / or cooling the pellets, which are transferred from the pelletizing device 3 via a pipe 33 to an inlet 18 or an inlet opening 19 of the discharge unit 2.

[0023] The discharge unit 2 has a funnel-shaped receiving chamber 21 for the pellets. A washing drum 22 for cleaning the pellets is provided in this receiving chamber 21 and is driven by the same drive unit 7 as the mixing drum 4. A sieve device is also provided in the discharge unit 2 for cleaning purposes. The cleaned and, if necessary, cooled pellets can then be fed via an outlet opening of the discharge unit 2 to a collection container (not shown).

[0024] In the feed unit 1, a further switching device 23 is provided for switching the motor 7 on and off for the mixing drum 4 and the washing drum 22. The switching devices 17 and 23 are part of an operating unit of the device, which is arranged at an ergonomically suitable distance from a base 24 of the assembly thus formed from the feed and discharge units 1, 2. To make the assembly 1, 2 mobile or movable, rollers 25 are provided on the base 24.

[0025] The feed unit 1 and the discharge unit 2 each have a cuboid housing made of sheet metal, with the feed unit 1 being mounted and fastened on the discharge unit 2.

[0026] The discharge unit 2 has a front wall 26, a rear wall 27, and opposing side walls 28. A base 29 of the feed unit 1 rests on a cover 30 of the discharge unit 2 and is detachably connected to the discharge unit 2 by means of fasteners not shown.

[0027] According to an alternative embodiment (not shown), only the feed unit 1 can be connected to the pelletizing unit 3. In this case, the feed unit 1 is arranged on a base 31, on which the pelletizing unit 3 is also arranged.

[0028] According to one embodiment of the invention (not shown), the pelletizing unit 3 is arranged below the feed unit 1 or the mixer 4 and the screw assembly 5. In this case, the discharge unit 2 has only a receiving chamber for the pellets, which can also be arranged below the feed unit. Alternatively, the discharge unit 2 can also be arranged horizontally offset from the feed unit 1. In this embodiment of the invention, no cleaning or cooling means are provided. In this embodiment of the invention, the device has a compact design that allows for easy placement or transport of the assembly thus formed.

[0029] According to a further alternative embodiment of the invention, the means for cooling and / or cleaning can also be arranged horizontally offset from the pelletizing unit 3 located below the feed unit 1. The pelletizing unit 3 is thus integrated into the movable assembly, making the device more compact and easier to transport.

Claims

[1] Device for producing pellets from renewable raw materials, in particular wood pellets, comprising a feed unit (1), a pelletizing device (3) and a discharge unit (2), characterized by , that the feed unit (1) - has a mixer (4) in which raw material particles can be mixed by adding a liquid and / or an additive and - has a screw assembly (5) arranged below the mixer (4) through which the mixed raw material particles can be conveyed in a first direction and an opposite second direction, wherein the feed unit (1) and the discharge unit (2) form a common assembly which is arranged next to the pelletizing device (3), wherein the outlet (15) of the feed unit (1) and the inlet (18) of the discharge unit (2) are arranged on the same front side of the assembly. [2] Device according to claim 1, characterized by, that the feed unit (1) and the discharge unit (2) are each designed as cuboid-shaped building units, with a front wall (8, 26), a rear wall (9, 27) and with opposing side walls (20, 28). [3] Device according to claim 1 or 2, characterized by , that the screw arrangement (5) is arranged directly below the mixer (4), wherein an upper first screw (5') and a lower second screw (5") are provided with a transfer section (12) on a rear wall (9) of the feed unit (1), so that the mixed raw material particles can be transferred from the upper first screw (5') to the lower second screw (5"). [4] Device according to any one of claims 1 to 3, characterized by, that the screw arrangement (5) is designed as a twin screw arrangement with only the upper screw (5') and the lower screw (5") and that the lower screw (5") has an outlet opening (14) on a front wall of the feed unit (1) for feeding the mixed raw material particles to the pelletizing device (3). [5] Device according to any one of claims 1 to 4, characterized by , that the discharge unit (2) has an inlet (18) with an inlet opening (19) for receiving pellets formed by the pelletizing device (3), to which a funnel-shaped receiving chamber (21) is connected, which is arranged below the feed unit (1). [6] Device according to any one of claims 1 to 5, characterized by , that the discharge unit (2) has means for cleaning and / or cooling the pellets. [7] Device according to claim 6, characterized by, that a washing drum (22) and / or a sieve device are provided as a means for cleaning the pellets. [8] Device according to any one of claims 1 to 7, characterized by , that the mixer (4) of the feed unit (1) and the means for cleaning the pellets of the discharge unit (2) are assigned the same drive unit (7). [9] Device according to any one of claims 1 to 3, characterized by , that the feed unit (1) or the discharge unit (2) is provided with rollers (25) for moving the same on a floor (31) on which the pelletizing device (3) is arranged.

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