CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a national phase application of PCT Application No. PCT

EP2018/070364, filed Jul. 7, 2019, which claims the benefit of the filing date of European Patent Office patent application No. EP3437741, filed on Aug. 3, 2017, the disclosures of which are incorporated by reference herein.

FIELD OF THE INVENTION

The invention refers to a comminution device comprising a feed opening for feeding material to be comminuted, a comminution shaft for comminuting the fed material, and a cutting chamber arranged between the feed opening and the comminution shaft and delimited by a cutting chamber wall.

PRIOR ART

Commercial waste, industrial waste, household waste, etc., e.g. (hard) plastic, textiles, composites, rubber or waste wood (such as pallets and chipboards) require comminution before they are finally disposed of or, in particular, before they are returned to the recycling cycle. Single-shaft or multi-shaft comminutors, which are for example fed by wheel loaders, forklifts or conveyor belts via a hopper for material feed, are particularly well known in the prior art for comminuting such waste.

A conventional comminutor comprises a rotor unit in a cutting chamber, which rotor unit comprises one or more comminution shafts equipped with ripping hooks or knives. The knives are for example fastened by screwing to knife carriers which can be welded into knife pockets or for example screwed on, which are milled into the comminution shaft. The comminution of the fed material takes place between the knives rotating with the comminution shaft and stationary, i.e. non-rotating, counter knives (stator knives, scraper combs). The rotor unit is driven by a motor (e.g. combustion engine/electric motor).

A conventional comminutor can also include a secondary presser that pushes or presses the fed material in the direction of the rotating rotor. After comminution between the rotating knives and the counter knives, the material can be discharged through a sieving device (if present), which determines the comminution factor according to the size of the sieve, and can be transported further by using a conveyor belt, a transport screw, a chain conveyor or an extraction system, etc. Material that is still too large is returned to the cutting chamber by the rotation.

For an efficient comminuting performance, it is of great importance to feed the material permanently to the cutting area. There are substantially two different approaches here:

Flat Cutting Chamber Wall

Some comminution devices have at least one flat cutting chamber wall, which delimits the cutting chamber on one side, in conjunction with a pressing system or secondary pressing system, which presses the material towards the rotor or counter knife. This can be, for example, a kind of pusher or a screw conveyor. Flat means that the cutting chamber wall near the comminution shaft has a small angle to the horizontal (e.g. within +1-20°).

The advantage here is that by reducing the pressure force of the secondary presser, even materials that are difficult to comminute can be comminuted without the machine coming to a standstill due to overload. However, the disadvantage is that the throughput capacity of the machine decreases considerably during the time during which the secondary presser retracts. On the other hand, materials that are easy to comminute require a great deal of force and thus also energy from the secondary presser in order to achieve high throughput rates.

Steep Cutting Chamber Wall

Other comminution devices work with a steep, in extreme cases even vertical, cutting chamber wall, whereby the material slides automatically to the cutting area due to its own weight, resulting in a great pull-in action. In addition, a secondary presser can be installed. Steep means that the cutting chamber wall near the comminution shaft has a large angle (e.g. greater than 45°) to the horizontal. If the cutting chamber wall is curved upwards, an even greater angle to the horizontal can then be provided at an upper end of the cutting chamber wall.

The throughput rate of a material averaged over a predetermined period of time without secondary pressing can be designated as pull-in mechanism or action.

A more constant throughput capacity/throughput rate is here advantageous, since the material slides permanently to the cutting area. A disadvantage is that the comminution of materials that are difficult to comminute (e.g. solid and/or coarse materials) is not possible at all, or only by increased force or energy expenditure of the rotor, or a permanently low dosage of the feed material.

DESCRIPTION OF THE INVENTION

It is the object of the invention to at least mitigate the disadvantages in the case of a steep cutting chamber wall with pull-in action of the material. The comminution device according to the invention is suitable for waste as described above in connection with the prior art.

The object is achieved by a comminution device comprising a feed opening for feeding material to be comminuted into a cutting chamber; at least one comminution shaft for comminuting the fed material, wherein the cutting chamber is arranged between the feed opening and the comminution shaft and delimited by cutting chamber walls, and wherein at least one cutting chamber wall is pivotable to thereby control the pull-in action of the fed material to the comminution shaft based on the fed material's own weight; and a control device for adjusting a pivoting angle of the at least one cutting chamber wall, wherein the control device controls the pivoting angle during operation of the comminution device depending on at least one selected from the group consisting of (1) a load applied to the comminution shaft; (2) a torque applied to the comminution shaft; (3) a current supplied to an electric motor driving the comminution shaft; (4) a hydraulic pressure supplied to a hydraulic motor driving the comminution shaft; and (5) an operating condition of an internal combustion engine driving the comminution shaft; and wherein the pivoting angle is adjusted in such a way that the pull-in action is reduced based on an increase in at least one selected from the group consisting of the load, the torque, the current, and the hydraulic pressure, respectively.

The comminution device according to the invention comprises a feed opening for feeding material to be comminuted, a comminution shaft for comminuting the fed material, and a cutting chamber arranged between the feed opening and the comminution shaft and delimited by a cutting chamber wall. The comminution device according to the invention is characterized in that the cutting chamber wall is pivotable.

The advantage of the comminution device according to the invention is that by pivoting the cutting chamber wall, the pull-in action of the fed material to the comminution shaft, which is based on its own weight, can be controlled.

The waste comminution device according to the invention can be further developed as follows.

The at least one cutting chamber wall can be pivoted during operation of the comminutor, in particular it is pivotable in an automatically controlled manner. In addition, or as an alternative, the at least one cutting chamber wall may be pivotable outside the operation of the comminution device, in particular manually pivotable.

Another development consists in the fact that the cutting chamber wall may be pivotable about a pivot axis parallel or substantially parallel to a rotation axis of the comminution shaft, in particular wherein the pivot axis may be provided at a lower end of the cutting chamber wall. Substantially parallel means that the angle between the direction (or direction vector) of the rotation axis of the comminution shaft and the direction (or direction vector) of the pivot axis is 10° or less, preferably 5° or less, most preferably 2° or less. The angle between the axes is therefore also defined for skew axes as the angle between the direction vectors. In this way, the cutting chamber wall can be placed close to the comminution shaft and/or the comminution shaft is uniformly fed along the axis or along the comminution shaft.

According to another development, the comminution device may also include a pressing device for pressing the material to be comminuted against the comminution shaft. The pressing device allows the material to be comminuted to be temporarily pressed against the comminution shaft with increased pressure to increase throughput.

A further development is that the pressing device can be pivoted together with the cutting chamber wall. This has the advantage that the relative position of the pressing device in relation to the cutting chamber wall is maintained (remains constant) when the cutting chamber wall is pivoted.

According to another development, the pressing device can be rotated around a rotary axis, in particular the rotary axis can be arranged parallel or substantially parallel to the pivot axis but offset to it. Substantially parallel means that the angle between the direction (or the direction vector) of the rotary axis and the direction (or the direction vector) of the pivot axis is 10° or less, preferably 5° or less, most preferably 2° or less.

The cutting chamber wall may comprise a cylindrical section therein, and the rotary axis of the pressing device may be arranged in the central axis of the cylinder. In this way it is possible for the pressing device to be at a constant distance from the cutting chamber wall during rotation of the pressing device relative to the cutting chamber wall.

According to another development, the comminution device may also include a control device for adjusting a pivoting angle of the cutting chamber wall. This allows the pivoting angle to be automatically adapted to the material to be comminuted during operation of the comminution unit.

This can be further developed in such a way that the control device adjusts the pivoting angle during the operation of the comminution device depending on a load applied to the comminution shaft and/or a torque applied to the comminution shaft and/or a current supplied to an electric motor driving the comminution shaft and/or a hydraulic pressure supplied to a hydraulic motor driving the comminution shaft and/or an operating condition (e.g. rotational speed) of an internal combustion engine which drives the comminution shaft, in particular wherein the pivoting angle is adjusted in such a way that the pull-in action is reduced when the load and/or the torque and/or the current and/or the hydraulic pressure increase.

The above-mentioned object is also achieved by a method for operating a comminution device as disclosed herein.

The comminution device comprises a feed opening, a comminution shaft and a cutting chamber arranged between the feed opening and the comminution shaft and delimited by a cutting chamber wall. The method comprises the steps: feeding material to be comminuted into the feed opening and comminuting the fed material with the comminution shaft, wherein the method is characterized by pivoting the cutting chamber wall to control the pull-in action of the fed material to the comminution shaft based on its own weight.

According to a further development, the pivoting of the at least one cutting chamber wall can take place during the operation of the comminution device, in particular by automatically controlled pivoting; or the pivoting of the at least one cutting chamber wall can take place outside the operation of the comminution device, in particular by manual pivoting.

The method according to the invention can be further developed by the step of pressing the material to be comminuted against the comminution shaft.

Another development consists in the fact that the following further step may be provided: adjusting the pivoting angle during the operation of the comminution device depending on a load applied to the comminution shaft and/or a torque applied to the comminution shaft and/or a current supplied to an electric motor driving the comminution shaft and/or a hydraulic pressure supplied to a hydraulic motor driving the comminution shaft and/or an operating condition of an internal combustion engine driving the comminution shaft.

The pivoting angle can be adjusted in such a way that the pull-in action is reduced when the load and/or torque and/or current and/or hydraulic pressure increase.

Further features and exemplary embodiments as well as advantages of the present invention are explained in more detail hereinafter with reference to the drawing. It goes without saying that this embodiment cannot exhaust the entire scope of the present invention. It also goes without saying that some or all of the features described below can also be combined in other ways.

