GB2217232A - Helical roll crusher - Google Patents

Abstract

The roll crusher comprises at least one crushing roll mounted for rotation in a casing open at least partly at top and bottom. The crushing roll has a peripheral helix 4, Fig 8. The helix whorls are formed with recesses 7, Fig 2 and thus with rippers 9. The recesses 7 are disposed offset on the periphery in consecutive whorls 6. A channel-like row 8 of recesses is thus formed, and extends not parallel to the roll axis 5 but helically therearound. Two crushing rolls 1 with or without recesses 7 can co-operate with a grating formed with crusher strips and crusher webs. The crushing rolls 1 can vary as regards speed and/or the pitch and/or number of helixes 4. …<IMAGE>…

Description

Agent's Reference: P5609GB-H/JCC/ac DESCRIPTION OF INVENTION Title: "Roll crusher" THIS INVENTION relates to a roll crusher for reducing waste, preferably bulky and in large pieces, and aims to solve the problem of so improving such a roll crusher that, more particularly, elongate waste can also be efficiently reduced without unnecessary reversing of the rolls and the consequent disadvantages regarding idle time and increased mechanical stress.

According to the invention, there is provided a roll crusher for reducing waste, preferably bulky and/or in the form of large pieces, characterised in that at least one crushing roll having at least one helix projecting like a web from its periphery is mounted for rotation in a casing open at least in top and bottom zones.

In one embodiment, a roll crusher comprises at least two rolls mounted parallel and side by side in a casing and driven in opposite directions when there is a central feed apparatus and formed with peripheral oppositely-directed helixes, a grating being disposed under the rolls, the rolls being driven at different speeds and/or the helixes having different pitches, and the grating comprising crusher strips adapted to the contour of the helixes, extending transversely t the roll axes, and interconnected by longitudinal crusher webs and the helixes rotating at short distances from one another.

The rolls may be driven by either an electromechanical or a hydraulic or a diesel-hydraulic system.

As a result of the co-operation of the rolls in conjunction with the grating disposed under the rolls, and also as a result of the construction of the rolls and the grating and the fact that the sequence of motions of the rolls can be controlled by the drive as required, the materials thrown in are reduced. The method of reduction is as follows: the material is drawn between the rolls and initially crushed and simultaneously pressed against the grating. In the process the material is pushed axially and transversely over the grating and finally crushed, so that it is automatically ejected through the outlet openings in the grating formed by the crusher strips and webs. The crushing process is reliable because the rolls continuously move and press the incoming material over the grating. The result is a self-cleaning effect on the outlet openings, which therefore cannot clog.

The axial and transverse flow of material between the rolls and the grating is influenced by the shape and motion of the helixes, which cause the material for reduction to move axially and peripherally.

The reduction sequence can be varied by altering the grating and the construction and sequence of movements by the helixes.

When the helixes rotate and have their pitch in opposite directions, the rolls can either rotate at different speeds and both have the same pitch and number of whorls, or can have the same speed and different numbers of whorls or different speeds and different number of wnorls.

The reduction process is made up of -a number of sequences, i.e. a crushing, tearing and shearing process.

Special importance is attached to the shearing process, since reduction b shearing uses less energy than rushing or tearing. Another result is much less noise, and an improvement in the environment.

Since there is preferably a difference in the speed of the helixes on the two rolls, the roll producing the slower axial feed slows down the material axially to some extent, as compared with the other roll. This results in the actual shearing process, because the roll with the faster axial feed overtakes the other roll in the axial direction. The rolls preferably operate in opposite directions, not only tangentially (peripherally) but also axially. The two crushing rolls preferably rotate or act in opposite directi ons. A double or triple pitch on one roll will additionally increase the axial relative motion on the peripheral surfaces of the helix, at the place where the rolls come close together.

The maximum size of an article for reduction which can be safely gripped by the rolls and drawn between them, will depend on the overall size of the roll crusher in question.

Apart from the shape and speed of rotation of the rolls, the shape of the grating has a critical effect on the reduction process, more particularly with regard to the particle size and the risk of clogging the outlet openings of the grating.

The various crushing edges of the crusher strips and crusher webs are preferably made in the form of particularly wear-resistant cutting edges having a specific shape.

Optionally, the outlet openings can be shaped so as to prevent clogging by material. In addition the material which continually presses over the rolls ensures a continuous flow through the outlet openings.

If the rolls jam or block, e.g. if they have to reduce too much material at once or material which is very hard in the operating direction of rotation, the rolls are prefer ably automatically switched to reverse, so as to run free.

The rolls remain reversed e.g. for a few seconds, during which they rotate in the opposite direction from normal, until they are automatically switched back to the operating direction of rotation.

Reversing can be initiated when preset loads on the rollers are reached (maximum torque and/or minimum speed) or by timed programming of a freely programmable electric control system. Timed program control is particularly suitable for materials which cake during reduction and may thus clog up parts of the grating, e.g. shrubbery with leaves and sticky soil. In the case of material of this kind, the set loading parameters for the rolls during the reduction process may-not be reached and consequently there will be no changeover to reverse unless the required command is given directly via a program control system.

When the rolls reverse, the already-reduced and the non-reduced material are subjected to a different crushing sequence, i.e. are not broken first between the two rolls and then between the rolls and the grating, but are now conveyed between the longitudinal inner walls of the crusher casing and rolls and initially broken, before the material is finally broken between the rolls and the grating.

The reversing of the two rolls therefore has to serve the following purposes.

To clean the grating when clogged. To this end, after reversing, the material striKes the grating from a different direction and at a different angle.

To release the rolls so that they can rotate in the operating direction after they have been blocked or jammed by material in the sad direction, and To protect the roll crusher from damage e.g. if relatively large pieces of iron are thrown in and cannot be crushed. The method of protection is as follows: the rolls switch off the crusher e.g. after two or three commands to reverse have been given in quick succession.

Preferably the crusher strips disposed underneath and transversely to the rollers are disposed close to and intimately follow the cylindrical contour of motion of the helical peripheral surfaces, and the highest points of the crusher strips form upwardly directed sharp ridges in the vertical central longitudinal plane between the crushing rolls. As a result of this configuration the material is regularly formed into a wedge when drawn through the crushing rolls and is initially split up and, owing to the simultaneous peripheral and axial movement, is conveyed out of the rolls and over the entire grating and in the process reduced to a finer particle size.

The particle size of the reduced material can be varied e.g. by changing the grating. If the gaps are particularly narrow and relatively deep, the material for reducing is automatically kept somewhat longer in the crushing zone, and is therefore crushed to an extent depending on the reduction process which occurs here. In addition to this effect, the apparatus can be used for another purpose, in addition to reducing material, i.e. for mixing various materials together and simultaneously reducing them.

The particle size can also be influenced by varying the frequency with which the rolls are reversed.

Material which has been thrown into the roll crusher, or material which has not yet been completely reduced and has not yet fallen through the grating rus; not be pressed in front of the end wall of the crusher casing in the direction of advance. To this end, a crusher roll can be equipped with two oppositely directed helix portions. In this construction, the length of one helix portion along the roll axis is about 25% of the length of the other helix portion on the same crushing roll. Alternatively, the lengths of the helix portions can be equally distributed (at least 50%, advantageously between 50 and 25%).

When the rolls rotate in the operating direction, material is conveyed backwards at one helix portion and forwards at the other helix portion. In the process, it is simultaneously reduced and expelled through the outlet openings in the grating in this region.

The crusher webs may be disposed substantially in the vertical central longitudinal planes of the rolls and have a slim trapezoidal cross-section which narrows downwards.

Alternatively, the crusher webs may be disposed substantially in the longitudinal vertical parting plane between the rolls and have a wedge-shaped cross-section with an upwardly directed knife edge.

Preferably the grating is mounted so as to be vertically pivotable around a longitudinal axis extending at the side of the crusher rolls.

If a part made of non-reducible material, e.g. a relatively large piece of iron, enters the roll crusher and is not ejected during the normal sequence of processes occurring in the crusher, the grating can be swung up so that the bulky piece of material can be removed manually.

The grating can also be swung up and cleaned when necessary, e.g. after treatment of sticky materials.

After the grating has been swung up, the rollers are also freely accessible from beneath, so that they can also be cleaned when necessary.

Preferably the vertically aligned crusher ribs which closely follow the contour of the helixes at the side of the rolls are formed on the inner walls of the casing.

Accordingly, reduced material which is not immediately ejected through the outlet openings when the rolls are rotating in the operating direction, strikes the inner walls of the crusher casing formed with ribs and, owing to the construction thereof, is deflected here and automatically conveyed by the two rolls back through the gaps between the rolls and the inner walls and up to the actual drawing-in region between the two rolls in the vertical central longitudinal plane of the crusher casing, where the material is drawn in together with material which has not yet been crushed.

An underlying idea of the preferred embodiment of the invention is for the recesses to be so integrated into the helix that a channel-like row of recesses does not extend parallel to the shaft axis, so that the rippers left by the recesses do not extend parallel to such axis either. It can therefore now be ensured that, irrespective of whether a roll having a helix co-operates with at least one other such roll or with a rigid abutment, elongate waste engaged by the rippers is pivoted out of a position in which it is parallel to the roll axis and is therefore supplied much more advantageously to the reduction process. This special arrangement of the recesses therefore ensures that waste which is disposed parallel to the roll axis is shifted into positions at an inclination to such axis.Jamming is therefore obviated and, therefore, so are the reversals previously necessary tc clear the jamming.

Another advantage of the preferred embodiment is that the transverse forces caused by jamming are substantially obviated. Wear of the roll bearings is reduced. The uptime is increased. Maximum loadings are reduced. Also, the drive loads are rendered uniform correspondingly. Another consideration in this connection is that power requirements are reduced since the reduction process is performed more satisfactorily overall.

The integration of the recesses to form a channel-like row extending to some extent helically of the helix axis can proceed irrespective of whether the helix extends continuously over the whole length of a roll or whether at least two oppositely arranged helixes are disposed on a single roll in order to retain the waste for reduction as far as possible in the central zone of the crusher.

Basically, the pitch of the helixes is of secondary importance. Also, two or more helixes can extend from one end o a roll to the other. In multiple-roll arrange=ents the number of helixes on the rolls and the speed thereof can be combined with one another as required.

Each helix may be formed with two or more rows of channel-like recesses. These features help further to accelerate the reduction effect since elongate waste remains parallel to the roll axes for only a short time, for even if there are only two diametrically opposite rows of recesses the rippers rotate the waste from its position parallel to the roll axis in as little as half a revolution of a roll.

In a parallel arrangement of at least two rolls the recesses of all the rows may be offset from one another in the same peripheral direction. Thus, all the channel rows extent in the same offset direction. Consequently, elongate waste can be engaged at one end by the rippers of one roll an at the other end by the rippers of the other roll and thus prevented from shifting into a position parallel to the rotational axes of the rolls. The waste is as it were clamped on alternate sides and therefore rotated relatively in its position and thus supplied in an advantageous manner to the reduction process without any risk of jamming.

Alternatively, in a parallel arrangement of at least two rolls the recesses of the rows of adjacent rolls may be offset from one another in opposite peripheral directions.

Thus, the recess rows of adjacent rolls extend, as it were, in a V-shaped relationship to one another. Conveniently in this case, the rolls rotate oppositely to one another and the rippers are effective in opposite directions to one another. This also leads in an advantageous manner to elongate waste which may be initially disposed parallel to the roll exes definitely being turned and, in a manner advantageous so far as forces are concerned, being reduced between the helixes.

Although the recesses of one row may be offset peripherally at different angles from whorl to whorl, the offset is preferably uniform and always at the same angle.

A convenient angular offset between the recesses of consecutive whorls is 100 in the light of practical circumstances governing the dimensional relationships of a roll crusher.

The offset between the first recess and last recess of a row over the length of a roll should be not more than 1800 to ensure satisfactory waste reduction. Preferably, however, the maximum angle is 900.

Preferably the rippers formed by the recesses are undercut and the bases of the recesses run out at an acute angle into the periphery of the helix. These features further enhance effective reduction. Also, redcejA material cannot -a= but can leave the recesses readily.

The end faces of the rippers facing the recesses are preferably wedge-shaped. These features further enhance penetration of the rippers into the waste and the resulting reducing effect.

Preferably the average depth of the recesses is about 70% of helix height. This feature further enhances the effectiveness of the rippers while avoiding jamming.

The rippers of all the rolls can be effective in the same operative direction as one another, or alternatively, the operative directions of the rippers of two rolls may be opposite to one another so that the waste is always drawn into the zone between two rolls.

When only a single roll is used, the same can cooperate with at least one toothed rack which extends adjacent the roll substantially in the horizontal plane of the roll axis. Another possibility would be for two toothed racks disposed opposite one another to extend in the horizontal plane of the roll axis.

Embodiments of the invention are described below, by way of example with reference to the accompanying drawings wherein: FIGURE 1 is a view in side elevation of a first form of a crusher roll for a roll crusher embodying the invention; FIGURE 2 is a vertical cross-section on the line II-II of Figure 1; FIGURE 3 is a view to an enlarged scale of a detail of the roll of Figure 2 viewed in the direction of an arrow III in Figure ; FIGURE 4 is a view in side elevation of a second form of a crusher roll; FIGURE 5 is a plan view of two crusher rolls disposed in parallel and adjacent relationship to one another; FIGURE 6 is another plan view of another arrangement of two crusher rolls disposed in parallel and adjacent relationship to one another; FIGURE 7 is a plan view of a crusher roll disposed between two toothed racks;; FIGURE 8 is a vertical cross-section through a roll crusher embodying the invention having a bottom grating or lattice or the like, FIGURE 9 is a plan view of the roll crusher of Figure 8, and FIGURE 10 is a plan view of the grating of the roll crusher of Figures 8 and 9.

A crusher roll 1 shown in Figure 1 forms part of a roll crusher (not shown in greater detail) adapted to reduce large and bulky waste such as stillage or forest and garden waste, waste timber such as railway sleepers, undergrowth and branches, industrial and bulky refuse, rubble and road surfacing. The roll 1 is rotatably disposed in a casing and comprises a cylindrical central tube 2 to the end faces of which are welded plates 3 visible in Figures 7 and 2 and which are perpendicular to the longitudinal axis of the roll. Extending between the two plates 3 is a helical metal strip 4, herein referred to simply as a helix. e helix 4 is of sheet metal of substantially uniform thickness and is thus of rectangular shape in section in a radial plane containing the (rotary) longitudinal axis of the roll.The helix 4 is welded along its radially inner edge to the periphery of tube 2. The helix 4 is welded to tube 2 radially of the roll axis 5, that is to say, in section in a plane containing the longitudinal axis of the roll, the major dimension of each of the sections through the helix lie perpendicular to said axis rather than, for example, being inclined to said axis in one direction or the other.

As can also be gathered from Figures 1 and 2, each whorl or turn 6 of the helix 4 is formed with two opposite recesses 7, i.e. the helix 4 is formed with recesses 7 in its outer edge, at substantially regular intervals such that there are two recesses 7 per complete turn of the helix.

However, successive recesses 7 around the helix are not arranged at precisely 1800 intervals, but at somewhat lesser or greater intervals so that, instead of the recesses 7 being arranged in two straight rows along the roll, on diametrally opposite sides of the roll, with said rows being parallel with the axis of the roll, the recesses are arranged in two opposing helical rows around the axis of the roll. In the arrangement shown in Figures 1 and 2, the angular spacing between successive recesses 7 along the helix 4 is slightly greater than 1800 so that the helical rows of recesses are of the same "hand" as the helix 4.

Thus, adjacent recesses 7 in each helical row of such recesses are offset anguarly with respect to one another, in the peripheral direction WR, by an amount OC of, for example, 100, about the axis of the roll. The same are offset from one another between consecutive whorls 6 in the peripheral direction WR in accordance with the extent of the helix 4 The maximum offset between the first recess 7 (i.e. the recess 7 at one end of the roll) and the last recess 7 (i.e. the recess 7 at the other end of the roll) is 900. A channel-like row 8 of recesses 7 therefore arses and extends not parallel to the roll axis 5 but therearound and at a distance therefrom after the fashion of a helix.

In Figure 1 the recesses 7 are shown only in the first two turns or whorls 6. The recesses 7 in the other whorls 6 are indicated merely by chain-dotted lining for the row 8.

Each recess 7 is undercut on its trailing edge to form, with the periphery 10 of helix 4, a ripping tooth 9, herein also referred to simply as a ripper. Depth T of the recesses 7 is at most 70% of helix height H, the depth T and height H both being measured radially with respect to the roll axis 5, from the surface of tube 2. The ripper end faces 11 near the recesses 7 are, as can be seen in Figure 3, wedge-shaped, i.e. the leading edges of the rippers are feathered or reduced in thickness to give these leading edges the form of blunt "cutting edges.

As Figures 1 and 2 show, two rows 8 disposed at a 1800 offset from one another around the periphery are present in the roll 1.

In the embodiment of a crushing roll 1' shown in Figure 4, two oppositely disposed helixes 4', 4" are welded to the periphery of a tube 2. As will be apparent, one helix portion 4' extends over about two-thirds of roll length and the other helix portion 4" extends over only approximately one-third of the length of the roll 1'. Other relative lengths are also possible.

The construction shown in Figure 4 is formed with recesses 7 which are offset from one another peripherally of the rolls 1' between consecutive whorls 6 in the manner shown in Figure 1. As will also be apparent, a further recess row 8 is disposed at an offset of 1800 around the helix periphery relatively to a first such row 8. The rows 8 in the helix 4' can continue into the helix 4".

Figure 5 shows an embodiment in which two crushing rolls 1' of the kind shown in Figure 4 are disposed one beside another in a crusher casing (not shown) in further detail. The helical rows 8 of recesses in the two rolls 1 extend in the same sense, that is to say are of the same hand, being both left-handed in the arrangement illustrated although the helical "rows" 8 in the two rolls 1' could equally both be right-handed. Two or more such rows 8 per roll 1' can be present.

The embodiment of Figure 6 shows a construction similar to that of Figure 5, the only difference being that in Figure 6, the recess rows 8 in the two rolls 1' are of opposite hands, i.e. one row 8 has the form of a right-hand helix and the other has the form of a left-hand helix.

Figure 7 shows an embodiment having a roll 1 of the kind shown in Figure 1. The roll 1 co-operates with toothed racks 12 disposed on either side of the roll 1 substantially at the height of the roll axis 5.

In the embodiment shown in Figures 8 to 10 two crushing rolls 1" are disposed in parallel and side-by-side relationship to one another in a casing 20 with a charging hopper 24. The rolls can be, for example, of the kind having the reference 1" without recesses 7. The two rolls 1 are effective in opposite operative directions WR. The arrangement of the hexes 4 corresponds to the embodiment of Figure 4 except that the helix portions 4' and 4" of one roll 1" are disposed in opposition to those of the other roll 1", A grating or lattice or the like 14 pivotable around a horizontal lateral axis 13 is disposed below the rolls 1".

The grating 14 is embodied by transverse crusher strips 15 separated from one another by substantially trapezoidal cross-section crusher webs 16 which extend substantially in the vertical longitudinal planes intersecting the roll axes 5. The crusher webs have cutting edges 17 extending substantially in the zone of the sharp top edges 29 of the crusher strips 15.

The same have at the centre separating or dividing wedges 18 adapted to the contour of the helixes 4. The ridges 19 of the wedges 18 extend in the vertical plane between the rolls In n and somewhat below the horizontal plane intersecting the roll axes 5.

Beneath the ridges 19 the crusher strips 15 are reinforced by roof-shaped or wedge-shaped crusher webs 25 which also have cutting edges 26, 27.

Also Figure 8 shows that vertically aligned crushing ribs 21 can be disposed in spaced-apart relationship to one another laterally adjacent the rolls 1" on the crusher casing 20. The ribs 21 are also adapted to the contour of the rolls 1" in the zone below the axes 5. They have immediately above the crusher strips 15 cutting edges 22 which project beyond the longitudinal edges 23 of shearing strips 28 which form a part of the bottom of the casing 20.

Claims (24)

1. A roll crusher for reducing waste, preferably bulky and/or in the form of large pieces, characterised in that at least one crushing roll having at least one helix projecting like a web from its periphery is mounted for rotation in a casing open at least in top and bottom zones.

2. A roll crusher according to claim 1, comprising at least two rolls mounted parallel and side by side in a casing and driven in opposite directions when there is a central feed apparatus and formed with peripheral oppositely-directed helixes, a grating being disposed under the rolls, characterised in that the rolls are driven at different speeds and/or the helixes have different pitches, and the grating comprises crusher strips adapted to the contour of the helixes, extending transversely to the roll axes, and interconnected by longitudinal crusher webs and the helixes rotate at short distances from one another.

3. A crusher according to claim 2, characterised in that at least one roll has two oppositely-directed helix portions.

4. A crusher according to claim 2, characterised in that the crusher webs are disposed substantially in the vertical central longitudinal planes of the rolls and have a slim trapezoidal cross-section which narrows downwards.

5. A crusher according to at least one of claims 2 or 4, characterised in that the crusher webs are disposed substantially in the longitudinal vertical parting plane between the rolls and have a wedge-shaped cross-section with an upwardly directed knife edge.

6. A crusher according to at least one of claims 2, 4 or 5, characterised in that the grating is mounted so as to be vertically pivotable around a longitudinal axis extending at the side of the crusher rolls.

7. A crusher according to at least one of claims 2 to 6, characterised in that vertically aligned crusher ribs which closely follow the contour of the helixes at the side of the rolls are formed on the inner walls of the casing.

8. A crusher according to claim 7, characterised in that the ribs are provided in the region between each two crusher strips.

9. A roll crusher according to at least one of claims 7 to 8, characterised in that the lower ends of the ribs end in a point and project beyond the longitudinal edges of shearing strips constituting components at the bottom of the crusher casing.

10. A roll crusher according to at least one of claims 1 to 9, in which recesses are formed in the ridges of the helixes, thus leaving rippers, characterised in that the recesses extend in a channel-like sequence over most of the length of the helix and are arranged at an offset from one another peripherally in the same direction in consecutive whorls of the helix.

11. A crusher according to claim 10, characterised in that each helix is formed with two or more rows of channel-like recesses.

12. A crusher according to at least one of claims 10 or 11, characterised in that in a parallel arrangement of at least two rolls the recesses of all the rows are offset from one another in the same peripheral direction.

13. A crusher according to at least one of claims 10 or 11, characterised in that in a parallel arrangement of at least two rolls the recesses of the rows of adjacent rolls are offset from one another in opposite peripheral directions.

14. A crusher according to at least one of claims 10 to 13, characterised in that the recesses in any row are offset by the same angle in the peripheral direction between consecutive whorls.

15. A crusher according to at least one of claims 10 to 14, characterised in that the recesses are offset from one another between consecutive whorls by an angle of approximately 100 in the peripheral direction.

16. A crusher according to at least one of claims 10 to 15, characterised in that the offset between the first recess and the last recess in any row is at most 180% and preferably 90%.

17. A crusher according to at least one of claims 10 to 16, characterised in that the rippers formed by the recesses are undercut and the bases of the recesses run out at an acute angle into the periphery of the helix.

18. A crusher according to claim 17, characterised in that the end faces of the rippers facing the recesses are wedgeshaped.

19. A crusher according to at least one of claims 10 to 7, characterised in that the average depth of the recesses is about 70% of helix height.

20. A crusher according to at least one of claims 17 or 18, characterised in that in a parallel arrangement of at least two rolls the rippers of all the rolls are operative in the same direction.

21. A crusher according to at least one of claims 17 or 18, characterised in that in a parallel arrangement of at least two rolls the rippers of adjacent rolls operate in opposite directions to one another.

22. A crusher according to at least one of claims 10, 11 or 14 to 19, characterised in that when only one roll is used, the rippers formed by the recesses are brought into operative engagement with at least one toothed rack extending parallel to the roll axis.

23. A roll crusher substantially as hereinbefore described with reference to, and as shown in, any one or more of the accompanying drawings.

24. Any novel feature or combination of features described herein.