EP0140869B1 - Waste comminuting apparatus - Google Patents

Abstract

1. A device for size reduction of refuse, with a housing (1) having a charging orifice (2), in the there underneath located working space whereof there are arranged with axial spacing a pair of comminuting roller driven in counter-rotation, each having several comminuting discs (6, 7) with peripherally fitted ripping teeth (20), which alternately mesh with each other, with a discharge shaft (3) connecting to the working space (29), a deflector element (9) fast with the housing for each comminuting disc (6, 7), which extends between the two drive shafts (4, 5) in the axial interspace (8) between two comminuting discs (6, 7, respectively) of one comminuting roller, characterized in that each deflector element (9) rests on a central girder (21) arranged parallel to the drive shafts (4, 5) underneath the working space (29), which at least partly covers the drive shaft (5, 4) traversing the interspace (8) and, on the side of the charging orifice, above the drive shafts (4, 5), is proximal to the comminuting disc (6, 7), of the other comminuting roller, projecting into the interspace (8) and is provided with a cutting edge (18) which cooperates with the ripping teeth (20) of the comminuting disc (6, 7).

Description

The invention relates to a device for shredding waste, according to the preamble of claim 1. Such a device is disclosed in the document GB-A-2 031 754 described below.

In devices of this type for comminuting any, in particular combustible, waste, it is introduced into a filling opening, is grasped by fangs on intermeshing comminution disks and conveyed between them by their counter-movement at low speed, whereby it is broken up or torn into smaller parts. In order to prevent, depending on the type of waste, to a greater or lesser extent waste residues wedging between the shredding disks that severely impair the function, wipers fixed to the housing are provided which engage between the shredding disks. Such a device is shown, for example, in AT-B-339 705, GB-A-1 558 423 and GB-A-1 574 027. The scrapers stand there from the vertical side wall of the housing and thereby fill the between the comminution rollers and a large part of the existing space on the side wall of the housing. This also prevents shredded material adhering to the shredding discs from being conveyed back upwards. However, this is particularly disadvantageous in the case of non-brittle or only slightly brittle waste, since a storage space is formed in the wall area below the rollers, which is filled with partially shredded material and, after a relatively short operating time, leads to high loads and ultimately to the plant being blocked. This also has a detrimental effect on the fangs and the drive.

It has also already been proposed to equip rolls with cutting knives (AT-B-320 405) running over their entire length or with a series of circumferentially offset knives (US-A-3 578 252) which interact with fixed central knife bars. Since the two counter-rotating rollers do not intermesh, the problems described above do not occur in this embodiment. However, there is an increasing risk that oversized waste parts suddenly block the entire facility by spreading between the cutter bar and the rotating cutter.

From DE-A-2 741 033 a file shredding machine is known which also has intermeshing shredding rollers, a ring being loosely arranged on the drive shaft in each space between two shredding disks, the inside diameter of which is larger than the diameter of the drive shaft and the outside diameter of which is smaller than that The diameter of the shredding roller is. The material drawn in between the shredding disks constantly urges each ring to the drive shaft in a horizontal or slightly inclined direction, as a result of which the diametrically opposite area of the ring partially emerges from the space between the disks. Any material that remains between the panes is thereby discharged to the outside. This document shredder is particularly suitable for shredding waste paper and similar materials that are cut into narrow, long strips. Their use for waste material of any kind, especially for bulky waste such as boxes, packaging boxes, waste with a higher moisture content, e.g. Pieces of bark etc. are hardly possible.

Another shredding machine for paper is described in GB-A-2 031 754. There, in each interspace of the intermeshing shredding rollers, there is an almost completely filling deflector element, these being threaded onto parallel, outside rods. The deflecting elements are each approximated to the opposing shredding disk to such an extent that they practically touch its cutting teeth in a curved section leading downward from the drive shafts.

In the section leading upwards, they jump back, forming a cutting edge at the level of the drive shafts, so that the paper is gripped between the fangs of the shredding discs. sufficiently enabling insertion gap is formed. The paper torn into longitudinal strips by the fangs is then cut into tiny pieces by means of the cutting edges of the deflector elements. This paper shredder is also not suitable for processing other waste, especially bulky, wet waste containing plastic parts.

The invention has now set itself the task of creating a crushing device with repelling elements that crushes any, especially combustible waste material, the clogging of the spaces is prevented as possible, so that it is less susceptible to interference. In a preferred embodiment, the comminuted waste material should also be suitable for briquetting in a screw press.

This object is achieved according to the invention by a device with the features specified in patent claim 1.

The cutting edge is preferably formed on a counter knife mounted on the deflector.

Due to the support by the central support, the deflecting elements can absorb extreme loads and represent massive counter knives which are comparable to the knife bar of the above-mentioned US-A-3 578 252 and AT-B-320 405.

Due to the cutting edges arranged on the inlet opening, in contrast to all known proposals, in which the cause of the malfunction is usually that the material is only partly shredded or not shredded by the rollers, the waste before and after is removed in the device according to the invention Indirectly shredded when entering the work area, ie only material with a size is processed between the shredding disks, which can in any case come loose from the device. The susceptibility to malfunction can be reduced even further if the cutting edge of each of the shredding disks assigned to the one shredding roller lies within the cylindrical envelope surface of the other shredding roller, so that the fangs of the shredding disks in the upper area as feed tools to the central shredding area between the two shredding rollers and the shredder if the end face of the deflecting element facing the comminution disk has a section that starts from the cutting edge and is concavely curved. The latter limits the receiving volume between two teeth of a rice milling disk and the Abweiselemen _t, so that this assists to define the size of the comminuted particles. A combination of two different types of comminution is achieved by shearing off a portion of the waste piece to be processed between each fang of a comminution disc and the corresponding deflecting element, and then immediately or simultaneously by the interaction of the fangs of the intermeshing comminution discs further dismemberment takes place.

Relatively bulky waste material, which is placed in the mostly funnel-shaped filling opening, can or the like with feed rollers. be brought into the attack area of the shredding rollers so that bridging is prevented as far as possible above the shredding rollers.

In a further embodiment, it is provided that the deflecting element surrounds the drive shaft passing through the intermediate space and preferably consists of two parts placed against one another in the common axial plane of the two drive shafts, the lower part of which rests on the central carrier. In this embodiment, the end face of the deflecting element on the inlet opening is convex in the section extending over the bridge area, whereupon a section preferably rising between the bridge area and the side wall continues in order to largely prevent a dead space there.

Since the shredding rollers only feed material particles of the desired size due to the design according to the invention, a special space is not necessary on the underside of the shredding device, the clearance of which then again brings with it the problems mentioned at the outset.

The shredding device is therefore particularly suitable for combination with a screw press, in that the outlet shaft forms the filler neck of a screw press, the press screw of which is arranged below the two drive shafts of the shredding rollers parallel to the latter, the end face of each deflecting element facing the shredding disk serving as a guide surface for the press screw represents shredded material to be introduced.

In the case of material that can be easily shredded, the discharge quantity can be greater than the screw capacity. However, this can be metered in a simple manner if a cutting edge is formed on the side of each slide facing the central web. It has no effect on the function of the comminution device if a short-term excess that possibly does not pass the slide is again conveyed upward by the fangs, since this consists only of material that has already been comminuted to the correct extent. Of course, the fact that, in a preferred embodiment, the space accessible from below between two axially successive shredding disks, in which a blockage could primarily be caused by material accumulations, is filled by the deflection elements. It has also been shown to be favorable in this embodiment if a recess is provided in the lower end face in the axially parallel projection of the free support end of a deflecting element projecting beyond the central support onto the lower part of the next displaced deflecting element, as a result of which an im in the exit region of the comminuted material results in a substantially axially parallel cavity through which material which has possibly penetrated between a deflecting element and an axially adjoining comminution disk can emerge more easily.

A further embodiment of the device according to the invention as a filling funnel of a screw press provides that the central web is U-shaped in cross section and forms the section of the screw tube which has the inlet opening. This version is characterized by a particularly low overall height, since the shredded material leaving the work area falls directly into the press screw or is even pressed into it.

The invention will now be described in more detail with reference to the accompanying drawings, without being limited thereto.

1 shows a vertical section through the working space of a comminution device according to the invention along the line II of FIG. 2, FIG. 2 shows a horizontal section along the line 11-11 in FIG. 1, FIG. 3 shows a vertical section along the line 111- 111 in Fig. 4 by a second embodiment as a hopper of a screw press, Fig. 4 is a section along the line IV-IV of Fig. 3, Fig. 5 is a vertical section through a third embodiment and Fig. 6 is an enlarged bottom view of third execution.

The shredding device, which consists of a housing 1 with an upper hopper 2 and a lower one Exit shaft 3 exists, contains in the part enclosed by the side walls 17 two counter-rotating crushing rollers which are arranged on the two drive shafts 4, 5. The two comminution rollers each consist of comminuting disks 6, 7 which are spaced apart from one another and which mesh with one another, so that an intermediate space 8 is provided between two comminuting disks 6 and 7 axially successive on a drive shaft 4 and 5, respectively. The shredding disks 6, 7 are equipped on their circumference with fangs 20, which are fastened, for example, in contact with one another in the circumferential direction on a carrier. In each intermediate space 8 with a shredding disk 7 or 6 of the other shredding roller, a deflecting element 9 is arranged in alignment, which is attached to the side wall 17, which surrounds the drive shaft 4 or 5 passing through the clearance 8, projects above the shredding roller downwards and on the underside an axially parallel center support 21 rests. The end face 10 of each deflector element 9 facing the corresponding comminution disk 6, 7 is circularly concave in an upper section 30 and approximated to the cylindrical envelope surface of the comminution roller. The outermost edge of each tear tooth 20 and the upper edge 18 of the end face 10 thereby continuously form effective shearing or cutting elements, which separate two pieces of low height from a piece of waste to be inserted vertically between the two shredding rollers in the height direction of the hopper. The height of these parts corresponds approximately to the peripheral distance of a tear tooth 20 compared to the previous one of the same shredding disk. It is also determined by the number of fangs 20 per disc and the staggered arrangement of the discs on the two drive shafts 4, 5, so that the height of the parts is rather less. The cutting edge 18 of the end face 10 is primarily formed on a counter knife 19 mounted on the deflector element 9.

In addition to the above-mentioned denomination in terms of height, there is also the size reduction stage, which also exists in known devices and which divides the material in the axis-parallel direction by the overlapping of the rotating size reduction rollers. The two essentially simultaneous crushing stages therefore only allow material particles below a size causing a build-up of dust or complete blocking to pass into the working space 29 between the two crushing rollers or between a crushing disc 6, 7 and the associated deflecting element 9, which on the underside without problems can exit freely.

Each deflector element 9 could, for example, be of U-like design in its basic form, one side leg being used for attachment to the side wall, the other side leg having the concave end face 10 and resting on the central support 21. The embodiment shown in FIG. 1, whose compact design can absorb particularly large forces, provides a deflecting element 9 which surrounds the drive shaft 4, 5. It preferably consists of two parts 11, 12 which are screwed together, for example. The upper region of each deflecting element 9, which spans the drive shafts 4, 5, is convexly curved in the first section 15, which extends from the cutting edge 18, to which an obliquely rising flat or concave section adjoins the side wall 17. The distance between the convex end face section 15 and the axis of the drive shaft 4 or 5 is less than the radius of the comminution disk 6, 7, so that the effective areas of the fangs 20 protrude radially. Material slipping on the wall of the filling funnel 2 slides along the inclined edge sections up to their transition into the convex sections 15, where it is gripped by the emerging fangs 20 and conveyed towards the cutting edge 18 on the counter knives 19. The lower end face facing the outlet shaft 3 is flat. Along these lower end faces of all deflecting elements 9, a horizontally adjustable slide 25 is provided per comminution roller, through which the partial opening 37 of the outlet shaft 3 created by the central carrier 21 can be changed, and which is provided with a cutting edge 26. The slide also enables the material particles to be shredded.

The end face 10 of each deflecting element 9, which faces the shredding disk 6, 7, and which ends in a tapering end 22, forms a guide surface 31 in the lower part 12 up to the central support 21 for the shredded material toward the partial opening 37, so that the one for the central support the deflecting elements 9 favorable central supports 21 do not impair the exit. In an axially parallel extension of the end 22 of each deflector element 9 of a comminution roller, a recess 23 is provided in each deflector element 9 inserted in an intermediate space 8 of the second comminution roller, so that continuous free spaces are created in this area on both sides of the central carrier 21. The shape of the recess 23 can be chosen arbitrarily. It enables a crushed material that has entered the space 8 to exit laterally.

In the annular space shown in FIG. 1 between the drive shaft 4, 5 and the deflecting element 9, a spacer ring 27 can be arranged, on the outer surface of which slanting grooves 28 are formed. These feed material that has entered there back into the gap between the shredding disk 4, 5 and each deflector element 9. The spacer ring 27 can also be formed by a roller bearing, so that a multiple bearing of each drive shaft 4, 5 is achieved.

The embodiment according to FIGS. 3 and 4 shows a comminution device as a filling funnel of a screw press. The shredder 1 and 2 consists of a housing 1 with a filling opening 2, in which feed devices can optionally be provided, a central part receiving the comminution roller and an outlet shaft 3, the opening width of which is small and the inlet opening into the Press screw 33 corresponds to the screw press.

The two shredding rollers in turn each consist of a plurality of shredding disks 6, 7, which are arranged in a rotationally fixed manner with axial gaps 8 on a drive shaft 4, 5 and which are equipped with tear teeth 20 on the circumference. Between each shredding disk 6 or 7 of a shredding roller, a deflector element 9, which is approximated to a shredding disk 7, the other shredding roller, is arranged in the intermediate space 8, which protrudes from the outlet shaft 3 through the working space 29 between the two drive shafts 4, 5 and into an inlet opening Cutting edge 18 runs out, which lies within the circumference of the shredding roller. Following the first arcuate section 30 of the end face 10 facing the comminution disk 9, a guide surface 31 for the comminuted material also closes here. The deflecting elements 9 are approximately L-shaped and extend below the drive shafts 4, 5 to the side wall 17, whereby they also rest on the central support 21. In this embodiment, however, the central support 21 is formed by a part 34 of the screw tube 35 with a U-shaped cross section, in which the press screw 33 runs. The guide surfaces 31 of the deflecting elements 9 are aligned on both sides with the inner surface of the U-shaped part 34, so that the comminuted material falls or is pressed directly into the open press screw 33. The size of the working space 29 is chosen so that for all materials to be processed at least a sufficient, but preferably an excess amount of the comminuted material is pressed into the press screw 33, so that a slight pre-compression can already be achieved. Between the part 34 of the worm tube 35 forming the central support 21 and the side walls 17, the shredding device is closed by base plates 39 on which the deflecting elements 9 also rest. It is therefore sufficient even in the case of heavy loads to have an L shape, so that an upper part 11 according to FIG. 1 can be omitted. Fig. 4 shows the thickness of each deflector 9 in the area of the working space 29 less than the width of each space 8 between the shredding discs 6, 7, so that in the lower part preferably by means of additional plates or the like. formed, further narrow guide surfaces 32 are provided, which prevent the passage of material between the drive shafts 4, 5 and the edges of the U-shaped part 34. Remnants that nevertheless get into the space near the side wall between the deflection elements 9 and are not conveyed upwards again by the comminution disks 6, 7 can optionally also be removed through cleaning openings in the side walls 17.

5 and 6 show a further embodiment in which the comminution device is part of a screw press. The two drive shafts 4, 5 of the shredding device are in turn mounted parallel to the pressing disk 33, each of which is equipped with the intermeshing shredding disks 6, 7 provided with tear teeth 20. A grid, a bar grate or the like extends below the comminution roller. through the outlet shaft 3, which divides its partial openings 37. The deflecting elements 9 again alternately extend through the working space 29 between the two drive shafts 4, 5, again from the central support 21, which (FIG. 6) forms a central rod of a bar grate 39, and they contact the tear teeth 20 of the shredding disks on the inlet opening side 6, 7 form approximate cutting edges 18. The lower section of each end face of the deflecting elements 9 again represents a guide surface 31 towards the partial openings 37. Sliders 25 are provided below the grid or the rod grate, which enable the correct metering of the amount of the crushed material to be fed to the press disk 33. To avoid material build-up, the openings of the grid or the spacing of the grate bars 38 are at least as large as the size of the material pieces comminuted between the tear teeth 20 and the cutting edges 18.

If the amount of material falling through the openings 37 cannot be absorbed by the press screw 23, the total passage area of the grate or bar grate is reduced by moving the slide 25. This can be done manually, but is preferably coupled to the screw press as a function of a function thereof.

6 shows the slide 25 in detail from below, that is to say from the side of the press screw 33. The slides 25 are formed by sheets which, in the closed state, also engage under the central support 21 which carries the deflecting elements 9 and have a toothing along their contact edges, for example the teeth 36 shown, which, in the closed state, completely close the outlet shaft 3 in an interlocking manner. With increasing pull-out movement of the slider 25, the openings 37 are gradually released from the center, FIG. 6 showing a central position. The slider 25 could also be moved in a different way than shown, parallel to the grate bars 38.

If the amount of material in the outlet shaft is greater than the amount that can be fed to the press screw 23, the comminuted material is taken up again by the comminution rollers with a correspondingly reduced passage cross section or is circulated until the total passage cross section of the outlet shaft 3 is increased again, so that essentially one the absorption capacity of the press screw 33 in a simple manner is achieved. Any further comminution that may take place during this is of no importance.

Claims (9)

1. A device for size reduction of refuse, with a housing (1) having a charging orifice (2), in the thereunderneath located working space whereof there are arranged with axial spacing a pair of comminuting rollers driven in counter-rotation, each having several comminuting discs (6, 7) with peripherally fitted ripping teeth (20), which alternately mesh with each other, with adischarge shaft (3) connecting to the working space (29), a deflector element (9) fast with the housing for each comminuting disc (6, 7), which extends between the two drive shafts (4, 5) in the axial interspace (8) between two comminuting discs (6, 7, respectively) of one comminuting roller, characterised in that each deflector element (9) rests on a central girder (21) arranged parallel to the drive shafts (4, 5) underneath the working space (29), which at least partly covers the drive shaft (5, 4) traversing the interspace (8) and, on the side of the charging orifice, above the drive shafts (4, 5), is proximal to the comminuting disc (6, 7), of the other comminuting roller, projecting into the interspace (8) and is provided with a cutting edge (18) which cooperates with the ripping teeth (20) of the comminuting disc (6, 7).

2. A device according to Claim 1, characterised in that the cutting edge (18) is formed on a counter- blade (19) mounted on the deflector element (19).

3. A device according to Claim 1 or 2, characterised in that the cutting edge (18) of each one of the comminuting discs (6, 7) of a deflector element (9) associated with one of the comminuting rollers is situated within the cylindrical envelope of the other comminuting roller.

4. A device according to one of Claims 1 to 3, characterised in that the fron face (10) of the deflector element (9) oriented towards the comminuting disc (6, 7) has a segment (30) extending from the cutting edge (18) in a concavely arcuate circulararc shape.

5. A device according to one of Claims 1 to 4, characterised in that the deflector element (9) surrounds the drive shaft (4, 5) traversing the interspace (8) and consists of two parts (11, 12) fitted together in the common axial plane of the two drive shafts (4, 5), of which the lower part (12) rests on the central girder (21).

6. A device according to one of Claims 1 to 5, characterised in that the discharge shaft (3) forms the feed intake of a screw press, the screw (33) of which is arranged underneath the two drive shafts (4, 5) of the comminuting rollers parallel to these, wherein the front face (10) turned towards the comminuting disc (6, 7) of each deflector element (9) constitutes a guiding surface (31, 32) for the comminuted material to be fed into the screw press (33).

7. A device according to Claim 5 and 6, characterised in that the central girder (21) divides the discharge shaft (3), and the discharge surface area of each partial aparture (37) can be adapted to the capacity of the screw press (33) by means of a horizontally displaceable slider (25).

8. A device according to Claim 7, characterised in that on that side of each slider (25) which points towards the central girder (21) a cutting edge (26) is formed.

9. A device according to Claim 5 or 6, characterised in that the central girder (21) has a U-shaped cross-sectionand forms that segment (35) of the press pipe (34) which carries the inlet opening.

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