WO2020007508A1

WO2020007508A1 - Separating device

Info

Publication number: WO2020007508A1
Application number: PCT/EP2019/051648
Authority: WO
Inventors: Ferdinand Doppstadt
Original assignee: Doppstadt Familienholding Gmbh
Priority date: 2018-07-02
Filing date: 2019-01-23
Publication date: 2020-01-09
Also published as: CN112041092A; DE112019003347A5; DE102018005187B3

Abstract

The invention relates to a device (1) for separating feedstock (2), comprising at least two worm shafts (3), wherein the worm shaft (3) comprises a central tube (4) and a helix (5) which extends in particular helically around the central tube (4) and has a plurality of windings (6), wherein adjacent windings (6) are spaced apart from one another by a winding distance (7) and wherein the conveying direction (X) of the worm shaft (3) extends at least substantially in parallel with the rotational axis (8) of the worm shaft (3). The winding distance (7) reduces at least in regions in the conveying direction (X) of at least one worm shaft (3).

Description

Disconnecting device

The invention relates to a device for separating feed material with at least two worm shafts, the worm shaft having a core tube and a spiral, in particular spiraling around the core tube, with a plurality of turns, with adjacent turns being spaced apart from one another by a winding pitch and wherein the conveying direction of the worm shaft runs at least substantially parallel to the axis of rotation of the worm shaft.

The invention relates in particular to the technical field of sorting and / or classifying feed material, especially in the area of waste separation. A clean or sufficiently precise separation of the feed material into different fractions gives the possibility of directly utilizing different fractions of the feed material or of being able to supply different post-treatment processes or stages. For example, large and / or elongated parts can be separated from smaller particles or components of the feed material.

In connection with the invention, the term “separating” encompasses both classifying and sorting. Classifying is understood to mean a mechanical separation process for solid mixtures, with different geometric features, for example the size, being used for the separation process. A division can include in coarse and fine goods. In this context, sorting is understood to mean a mechanical separation process in which a solid mixture with different material characteristics is divided into fractions with the same material characteristics. The density, color, shape and wettability or magnetizability of the feed material are suitable for sorting, for example. Accordingly, the term separation in the vorlie invention includes a separation of the feed so that it can be divided into different fractions. This separation or separation is mostly used for the processing of recycling material or for the classification of at least essentially solid material.

EP 1 570 919 B1 discloses a device for sorting essentially solid material, in the known device so-called spiral rollers or worm shafts as rotation elements rotate about their longitudinal axes. The spiral rollers are arranged parallel to one another in approximately one plane. orderly. In addition, the spiral rollers are only supported on one side, engage in one another and have the same direction of rotation. In the known device, the feed material is fed at least substantially transversely to the longitudinal axis or axial direction of the spiral rollers or specifically in the axial direction of the spiral rollers. The known device is designed to separate the materials to be sorted into two fractions above the spiral rollers, namely into a long fraction and a fraction of cubic parts above the spiral rollers. A third fraction can be separated underneath the spiral rollers, the third fraction comprising, for example, the fine material of the feed material. A discharge of at least one fraction above the spiral rollers can take place across the open side transversely to the longitudinal axis of the spiral rollers, since these are only held on one side.

A disadvantage of the separating device known from EP 1 570 919 B1 is that feed material made of lumpy, hard material, in particular stones, pebbles, rubble and / or metal parts, such as screw nuts, in particular with an at least essentially cubic structure, can be clamped between the spiral rollers , When the feed material is pinched in this way, strong local overload events can occur. Such an overload event can result in severe machine damage, which can result in a prolonged downtime. Ultimately, due to the overload event, the connecting means of the drive device, in particular special gear roller chains, which connect the screw shafts, can loosen or jump off or even tear.

In addition, a high noise or noise level occurs in an overload event, accompanied by a loud crunch and other, especially high-frequency, noises. Such shrill noises are often due to Ver wear processes.

Incidentally, the separation result for highly branched feed material and / or for feed material with an increased layer height is usually unsatisfactory and a separation into different functions cannot be adequately guaranteed.

The object of the present invention is to avoid or at least substantially reduce the disadvantages in the prior art.

In a device for separating the type mentioned in the introduction, the aforementioned object is at least essentially achieved according to the invention in that the Winding distance of at least one worm shaft increases at least in regions in the conveying direction. Preferably, the distance between the turns increases, at least in regions, for all, in particular special, parallel and / or intermeshing, screw shafts in the conveying direction.

A widening of the winding spacing in some areas is to be understood according to the invention in such a way that the length of at least two successive winding spacings increases in the conveying direction. The length preferably increases by at least three, more preferably by at least four, successive turns in the conveying direction.

The conveying direction is understood to be the direction which runs at least substantially parallel to the longitudinal extension of the core tube and parallel to the axis of rotation of the worm shaft. The device according to the invention can also have a further conveying direction, which can be provided orthogonally and / or transversely to the axes of rotation of the worm shafts. The distance between two successive turns of the helix characterizes the pitch of the spiral, in particular the spiral, the pitch of the turns being the pitch of each 360 ° of the helix (one revolution). Consequently, a 360 ° section of the helix is to be understood as a turn and the length or distance from the start of the one turn to the start of the turn immediately adjacent in the conveying direction is to be understood as the turn distance. The winding spacing or the pitch of the helix can thus be interpreted analogously to the pitch of a spiral spring.

When the invention came about, it was recognized that the overload events occur due to the jamming of the feed material between the worm shafts when the feed material is caught in a gap between two worm shafts. The screen gaps arise between two immediately adjacent screw shafts between the respective immediately adjacent helixes when the helixes of the worm shafts interlock. The separation grain or the fine grain fraction is separated out via the screen gaps. A screen gap has an at least parallelogram-shaped opening.

It has also been recognized that overload events and jamming of the feed material usually occur in a screen gap when the screen gap narrows in the conveying direction. Such a reduction can result from a decrease in the winding spacing of a worm shaft in the conveying direction, what is due to manufacturing technology. In practice, it is usual to weld the, in particular previously rolled, coil to the core tube, with welding solutions generally showing a greater deviation in precision than components produced by machine, preferably by turning and / or milling.

Frequently - as has been shown in tests carried out - jamming of feed material in the sieve gap due to a reduction in the sieve gap in the conveying direction, especially in applications with a high proportion of very hard, cubic feed material in the border area of the separating grain size, which is separated via the sieve gap will be on.

According to the invention, a technical solution can consequently be provided which is very likely to reduce the frequency of such local overload events. According to the invention, the screen gap, in particular the width of the screen gap, advantageously increases in the conveying direction, so that jammed feed material, in particular cubic feed material, can be separated out as a fine grain fraction below the worm shaft deck. As a result, the constraint and the previously described, borderline and critical dimension of the screen gap can be avoided. As a result, it can also be reliably prevented that changes in pitch or changes in length caused by manufacturing tolerances between immediately successive winding distances lead to a local reduction in the width of the screen gap.

The operating conditions of the separating device are ultimately significantly improved by the invention, since overload events, in particular due to, preferably cubic, feed material which is clamped in the screen gap, can be reduced by up to 80%. This increases the operating time of the entire separating device and also reduces the operating costs when using the separating device according to the invention, since expensive repairs after a machine breakdown due to an overload event can be significantly reduced, preferably by more than 70%.

In addition, according to the invention, the noise level during operation of the device can be significantly reduced, preferably by at least 30%. In addition, the overload events accompanied by shrill noises and loud crunching can be safely prevented. Due to the, preferably increasing, increase in the spacing of the turns of the worm shaft in the conveying direction, the feed material is pulled apart in the axial direction of the conveying screws - that is, in the conveying direction. At the free end and / or shedding end of the worm shaft, the distance between the turns is thus preferably greater than at the end or end of the bearing. The distance between the turns and the free end and / or discharge end preferably increases. The conveying direction extends from the end of the task to the end of the discharge.

The pulling apart of the feed material causes a reduction in the layer height of the feed material towards the end of the discharge and thus brings about an improvement in the separating effect. By at least in some areas increasing the distance between the turns in the conveying direction of the worm shaft, the separation result can be achieved by better branching of interlocked feed material.

In a particularly preferred embodiment, it is provided that the threads of immediately adjacent worm shafts mesh with one another. When the helixes of the worm shafts mesh, a self-cleaning process can be achieved, with almost a non-winding system or device being available. This means that feed material can be reliably prevented from wrapping around the outside of the worm shafts or from "winding up" on them. The outer edge of the helix of an immediately adjacent worm shaft engages in the space between two turns of the helix of the immediately adjacent worm shaft. Accordingly, meshing of immediately adjacent worm shafts is provided.

The intermeshing of the helixes leads to the, preferably parallelogram-shaped, opening between the directly opposite helixes of the worm shafts, the opening also being referred to as the screen gap. This gap defines the size of the separating grain that is separated below the deck. This clear dimension therefore characterizes the angle of rotation offset between two adjacent worm shafts. By intermeshing the worm shafts, highly branched or adhering feed material can be separated from one another and divided into different fractions. Likewise, the exposed surface of the core tube can also be freed of feed material adhering to the core tube, in particular loam-containing. In addition, it is provided in a further preferred embodiment that at least two immediately adjacent worm shafts, in particular al le worm shafts, have the same direction of rotation. The same sense of rotation of the worm shafts ultimately results in a further conveying direction orthogonal to the axis of rotation. In the direction of the further conveying device, in particular elongated feed material can be separated.

The device is preferably designed in such a way that it is separated into at least three fractions, in particular with separation into at least two fractions above the screw shafts. The first feed material can be separated in the conveying direction parallel to the axis of rotation. In this direction of conveyance, in particular cubic, not elongated feed material is separated. Another fraction can take place below the spiral shaft deck or below the spiral waves, the separating grain size resulting from the screen gap between immediately adjacent screw shafts. A third fraction can finally be separated in the direction of the further conveying direction orthogonal to the axes of rotation, the third fraction comprising elongated, non-cubic feed material which preferably has a length of greater than one turn spacing, preferably greater than two turn spacings.

Ultimately, however, it can also be provided that the worm shafts, in particular at the ends, have a different direction of rotation in sections.

It is very particularly preferred that the winding spacing of all worm shafts increases at least in regions in the conveying direction. The increase in some areas is to be understood according to the invention in such a way that the length of at least two immediately successive turns of a worm shaft increases in the conveying direction. An advantage of the increase in the distance between the turns of all worm shafts in the conveying direction is that, in the case of intermeshing worms, the screen gap increases at least in regions in the conveying direction. In this way, feed material jammed in a screen gap can be separated in the conveying direction by means of a transport along the worm shaft.

For the rest, according to a preferred embodiment of the inventive concept, it is provided that the winding spacings in the conveying direction increase monotonously, preferably strictly monotonously. According to the invention, a monotonous increase in the winding spacing is understood to mean that the winding spacings increase in the conveying direction or remain at a constant level. If n the Indicates the number of turns and a _n the length of the turn spacing after n turns, this means:

The number of turns n increases in the conveying direction.

According to the invention, a strictly monotonous increase in the winding spacing is understood to mean that all winding spacings increase in the conveying direction:

3n-1 <3n

A monotonous increase in the winding spacing in the conveying direction accordingly means that immediately adjacent winding spacings in the conveying direction either increase or stagnate at a constant value. In the end, it is possible according to the invention that the worm shaft has a constant turn pitch / pitch up to half of its effective length, in particular starting from the clamping point, and on the second half the turn pitch is monotonous, preferably strictly monotonous, in particular non-linear and / or disproportionate , preferably exponentially, increases.

Consequently, a strictly monotonous increase in the winding spacing in the conveying direction means that all immediately adjacent winding spacings in the conveying direction increase, so that the winding spacing in the conveying direction increases in particular continuously or continuously. An advantage of such an increase in the winding spacing is that it can be prevented in this way that the length and / or size of the screen gap could be reduced after the screen gap has widened. A monotonous, preferably strictly monotonous, increase or increase in the spacing of the turns can ensure that the screen gap of directly adjacent screw shafts increases or increases monotonically, preferably strictly monotonously, in the conveying direction.

In addition, the percentage increase in the winding spacing in the conveying direction between two immediately adjacent winding spacings is preferably at least substantially the same. Consequently, between two immediately adjacent winding distances, the winding distance that is subsequently seen in the conveying direction is at least substantially greater by the same percentage increase factor. To calculate the length of the turns after n turns, an analogy to the compound interest increase can be assumed. The distance after n turns is thus calculated by the distance or the length of the first turn distance ao and the percentage increase in the slope or the turn distance p in the conveying direction:

n = number of turns

ao = length of first turn spacing

a _n = length of the turn spacing after n turns

p = percentage increase

Ultimately, it goes without saying that in practice there are deviations due to manufacturing tolerances for the theoretical calculation of the increase in the winding spacing. In particular, the deviation due to manufacturing tolerances to the calculated length of the turn spacing amounts to +/- 20% for up to ten turns.

Furthermore, according to a preferred embodiment, it is provided that the percentage increase in the winding spacing in the conveying direction is greater than 1%, preferably greater than or equal to 2%, preferably between 2% to 20%, more preferably between 4% to 10%, very particularly preferably between 4% to 6%. In practice, it has been found that, due to the welding position of the worm shafts, tolerances in the pitch or the winding spacing of the helix of a maximum of 2% per winding spacing or per 360 ° Qe revolution) of the helix, in particular of a maximum of 1% each Distance between turns or 360 ° e revolution) of the helix. According to the invention, the percentage increase between two immediately adjacent win spacings in the conveying direction exceeds the possible fierposition tolerance of the winch spacing resulting from the position of the worm screw worm shaft, so that it can be reliably ensured that the winding distance in För direction can increase at least in certain areas. Consequently, the sieve gap in the conveying direction can also increase at least in some areas.

Preferably, the pitch or the turn spacing as a whole increases - in comparison from the smallest to the largest turn spacing, that is to say from the beginning of the shaft or the end of the task to the end of the shaft or the end of the discharge - by up to 70%, preferably between 30% to 60%, more preferably between 40% to 50%.

In a further preferred embodiment of the inventive concept, it is provided that the smallest distance between immediately adjacent helixes and immediately adjacent worm shafts increases in the conveying direction. The smallest distance preferably increases monotonically, more preferably strictly monotonously, in the direction of conveyance. Immediately adjacent coils include two distances, the smallest distance between the coils and the separation grain size distance, which indicates the width of the larger screen gap. Consequently, the separation grain size spacing of immediately adjacent coils and immediately adjacent worm shafts preferably also increases in the conveying direction, in particular the separation grain size spacing increasing monotonously, preferably strictly monotonously, in the conveying direction. The separation grain size distance thus defines the distance between adjacent turns of adjacent coils.

The distance between adjacent turns of adjacent coils is preferably adjustable. In this way, a separation of materials that are difficult to separate with a screen gap adjustment option can be guaranteed.

The worm shafts are arranged in such a way that they form a screen deck, which is mostly used for classifying solid and lumpy application or feed material. The screen deck can have a screen length - transversely to the conveying direction - of 2 to 10 m, preferably of 4 to 6 m. The wire width or the length of the screw shaft in the conveying direction is between 0.5 to 5 m, preferably between 1 to 4 m, more preferably between 2 to 3 m. The device is intended for the separation of feed material from the recycling sector and for waste material, commercial waste and building rubble. The different task goods mentioned above have in common that they do not have equally distributed structures and geometries, and it is possible that goods to be fed are hooked together.

Especially when used in waste and recycling areas, an adjustment of the screen deck or screen size is advantageous for a clean or sharp classification of the feed material, in such a way that the smallest distance between the outer helical edge of the worm shaft and the immediately adjacent outer helix edge of the immediately adjacent worm shaft seen in the axial direction is changed. Ultimately, in order to change the screen deck, the worm shafts are rotated against each other so that the one between two immediately adjacent changes the existing free space and either becomes larger or smaller.

In practice, different configurations of the screen deck have been shown to be particularly advantageous. For example, a very small minimum distance and consequently a large distance between adjacent windings or a large separation grain size distance between two immediately adjacent coils was suitable for providing a large clearance or a large screen gap between two immediately adjacent core tubes and accordingly this arrangement enables a very large passage width, so that this arrangement is mostly used to separate elongated feed material or long parts.

By twisting or adjusting adjacent spiral waves arranged continuously in the working direction or in the direction of the further conveying direction, the smallest distance or the clear distance in the axial direction can be variably changed and also set to a maximum value, so that the free space between immediately adjacent worm shafts is kept to a minimum. This position can be used, for example, to separate less elongated material or bottles.

With the aforementioned settings, it is advantageous if all worm shafts have the aforementioned position with respect to one another or all worm shafts are at least essentially equivalent or in the same way to one another.

The setting of the screen deck or a change in the position of the worm shafts, in particular when the worm shafts are rotated, is also referred to as the setting of the angle of rotation offset. A changed position of the worm shafts from one to the next, relative to one another, enables the classification behavior to be influenced in the same way.

By rotating the worm shafts relative to one another and / or by changing the offset of two adjacent worm shafts, material with an at least substantially cubic and / or with an at least substantially non-elongated shape can be screened, in particular approximately, as a separating grain and / or sieve passage become. Feed items with a length that exceeds 2.5 to 4 turns or spiral pitches, in particular, remain above the screen deck. If a piece of goods has a length in the If the limit range is 1, 5 to 3 turns or pitch units, the separation cannot be deterministic but random.

The smallest distance between the coils affects not only the passage width or the size of the separating grain, but also the fraction and / or the fractions which are / are separated transversely or in the direction of the axis of rotation. By rotating the screw shafts to each other, a different process result or a different classification result can be made possible. Depending on the task at hand, adjustment of the classification result and the fraction to be deducted can be flexibly guaranteed.

According to a preferred embodiment of the inventive concept, as previously mentioned, the coils of immediately adjacent worm shafts interlock, with the radial distance from the outer helical edge to the core tube directly adjacent to the outer helical edge preferably being greater than 1 mm. In particular, the distance is in a range between 2 and 3 mm. Accordingly, there is the distance from directly adjacent core tubes via the web height of the coils and the distance from the outer edge of the coil to the core tube, that is to say ultimately the web height plus a few millimeters. Preferably, all worm shafts have at least essentially the same web height. The worm shafts are particularly preferably of at least substantially identical construction.

In addition, a drive device can be provided which drives the worm shafts at a synchronous angular velocity. Consequently, the worm shafts preferably all rotate in the same direction and are also driven at the same angular velocity, as a result of which the distance between adjacent windings does not change in the operating state of the device. The drive device can have a plurality of connecting means, in particular gear roller chains, which each interact with a drive means of the worm shaft. For example, at least one gear wheel can be provided as the drive means. It is preferred that the motor of the drive device is arranged only on one worm shaft. The further worm shafts are connected to this worm shaft via the connecting means, where one connecting means connects two directly adjacent worm shafts so that two connecting means are arranged on each worm shaft - apart from the worm shafts on the edge. In this context, another advantage of the invention can be seen. So far it has been the case that if a feed material gets caught in the middle of the screen deck between two worm shafts and can no longer be conveyed in the conveying direction, the worm shafts connected to one another by the clamped-in feed material can no longer rotate. As a result, all worm shafts following in the direction of further conveyance, which are connected to the fixed worm shafts, can no longer rotate. Medium bar, however, all worm shafts are connected to the motor of the drive device. As a result, at least part of the screen deck is at a standstill, and tearing of the connecting means - consequently the gear roller chains - cannot generally be prevented, so that serious damage to the drive device can occur. According to the invention, this problem can be avoided by increasing the distance between the turns in the conveying direction.

The core tube is particularly preferably at least substantially cylindrical, in particular with the core tube having a constant outer diameter in the conveying direction.

The axes of rotation of the worm shafts are preferably arranged parallel to one another and / or run parallel to one another, as a result of which the separation result can be optimized since the feed material is conveyed in the conveying direction and in the direction of the further conveying direction, that is to say transversely to the axis of rotation, over the screen deck can be.

The worm shafts can be arranged such that they form a flat or curved screen deck. In particular, the worm shafts are arranged in a horizontal or inclined plane or curved, preferably trough-shaped. In addition, the worm shafts can be supported on one side or on both sides in a formation. The choice between a flat or a curved screen deck can be made depending on the application and the feed material. A curved screen deck is particularly useful when feed material is to remain above the screen deck for a longer period. A combination of a flat and a curved screen deck can also be adapted to the process conditions depending on the application.

The use of one-sided and double-sided folding depends on the application of the separating device. With one-sided fluttering it is partial that a separation into at least two fractions can take place, namely into a fraction below the screen deck, a fraction in the direction of the further conveying direction, that is to say transversely to the axes of rotation, and a fraction in the conveying direction, that is to say at least substantially in parallel to an axis of rotation. Bearing on both sides can create a high level of stability of the screen deck, enable the classification of feed material with a very high dead weight and be designed to be safe against overloading or overstressing, so that machine breakage can be safely avoided. A separation into three fractions can also take place in the case of storage on both sides, wherein the fraction can be ejected in the conveying direction, that is to say in the direction of the axis of rotation, over the storage.

In particular, the folding with the worm shafts and / or the screen deck is designed to be tiltable in at least one direction, preferably in all directions. The fleas of the folding can be made adjustable. Accordingly, the entire screen deck with the worm shafts can be inclined depending on the respective application, in particular the feed material to be classified. Further features, advantages and possible uses of the present inven tion result from the following description of Ausführungsbeispie len with reference to the drawing and the drawing itself. Here, all described and / or illustrated features for themselves or in any combination on the subject of the present invention , regardless of how they are summarized in the claims and how they relate.

It shows:

1 is a schematic plan view of a device according to the invention for separating feed material,

2 shows a schematic perspective illustration of a further embodiment of a separation device according to the invention, FIG. 3 shows a schematic perspective illustration of a further embodiment of a separation device according to the invention, 4 is a schematic perspective view of a worm shaft according to the invention,

Fig. 5 is a schematic perspective view of the screw shaft according to the invention shown in Fig. 4 and

Fig. 6 is a schematic side view of the screw shaft according to the invention shown in FIGS. 4 and 5. 1 shows a device 1 for separating feed material 2 with at least two screw shafts 3. In FIG. 1, six screw shafts 3 are shown. The worm shaft 3 has a core tube 4 and a helix 5 with a plurality of turns 6. In the illustrated embodiments, the helix 5 runs spirally around the core tube 4. A turn 6 characterizes a revolution / rotation of the helix 5 by 360 °. Adjacent windings 6 are spaced apart from one another by the winding spacing 7. The winding spacing 7 is the so-called pitch of the helix 5. The conveying direction X of the worm shaft 3 runs at least substantially parallel to the axis of rotation 8 of the worm shaft 3. The conveying direction X extends from the feed end 17 - that is, the supported end - up to the discharge end 16 of the worm shaft 3. The discharge end 17 is shown as the free end of the worm shaft 3. In further embodiments, not shown, the discharge end 16 can also be supported.

1 also shows that the winding spacing 7 in the conveying direction X of at least one worm shaft 3 increases at least in regions. In the embodiments shown, it is shown that the winding spacing 7 not only increases in part but also over the entire longitudinal extent of the worm shaft 3. It is not shown that the winding spacing 7 only increases in sections or in regions over at least two adjacent winding spacings 7 in the conveying direction X. For example, starting from the clamping point or the beginning of the worm shaft 3, thus the feed end 17, the win distance 7 only increase from half the length of the worm shaft 3 in the direction of conveyance X. The direction of conveyance X results in each case for a worm shaft 3 and follows from the rotational movement of the worm shaft 3 - consequently from the rotation of the helix 5. FIG. 2 shows that the feed material 2 is fed via a loading device 14 by means of a loading device 15, in the exemplary embodiment shown a conveyor belt, onto the screen deck formed by the screw shafts 3. Here, cubic and / or non-elongated materials are separated in the direction of the conveying direction X - that is, above the screen deck. The separation grain or the fine grain fraction, that is, the smaller components, falls between the spaces between two immediately adjacent worm shafts 3 and thus below the screen deck. A third fraction can be deposited transversely to the direction of conveying X in the direction of the further conveying direction Y, whereby this fraction can comprise elongated feed material 2. The further conveying direction Y extends orthogonally or transversely to the conveying direction X.

1 to 3 show that the spirals 5 of immediately adjacent worm shafts 3 interlock, so that there is a meshing of the worm shafts 3. This causes the so-called self-cleaning effect of the screw shafts 3, since the surface can be kept free of feed material 2 adhering to it, for example, clay-containing feed material 2. In addition, wrapping of feed material 2 around the worm shaft 3 can be reliably prevented.

In addition, it is provided in the illustrated embodiments that we have at least two immediately adjacent worm shafts 3 in the same direction of rotation. According to the illustrated embodiment, all Schneckenwel len 3 have the same direction of rotation. The same direction of rotation of all worm shafts 3 enables the further conveying direction Y transversely to the conveying direction X and consequently transversely to the axes of rotation 8.

1 shows that the winding spacing 7 of all worm shafts 3 increases in the conveying direction X at least in some areas. In Fig. 1, the number of turns 7 of all worm shafts 3 in the conveying direction X increases not only in sections but also over the entire longitudinal extent of the worm shafts 3.

4 to 6 show that the turns 7 in the conveying direction X increase monotonously. According to the embodiment shown in Fig. 6, the winding spacing 7 in the conveying direction X increases strictly monotonously. A strictly monotonous increase in the winding spacing 7 requires that the winding spacing 7 following in the conveying direction X is always greater than the previous winding spacing 7 seen in the conveying direction X. Consequently, a ratio of the turns 7 is as follows: ao <ai <a ₂ <a ₃ <a ₄ <as <a6 <a7

The winding spacing ao is the smallest winding spacing 7, which increases in a strictly monotonous manner in the conveying direction X, up to the winding spacing a.

In an embodiment that is not shown, it is provided that the winding spacings 7 increase monotonically in the conveying direction X, but not strictly monotonically. For example, the winding spacings ao to a _{4 can be of} identical or identical design and only from the winding spacing as to the winding spacing a7 grow strictly monotonous. The result is: ao = ai = a ₂ = a ₃ = a ₄ and

a ₄ <as <a6 <a7

Alternatively, according to a further embodiment, it is also possible: a ₀ = a and

ai <a ₂ <a ₃ <a ₄ and

a ₄ - as ^- 3Q and

For the rest, in the embodiment shown in FIG. 6 it is provided that the percentage increase p of the winding spacing 7 in the conveying direction X between two immediately adjacent winding spacings 7 is at least essentially the same. This means that the increase p between two winding distances 7, for example between ai and a ₂ , is the same as the increase p of the winding distance 7 between a ₄ and as. The winding distance 7 a _n can thus be after n turns 6 - by analogy to increase compound interest - be calculated as follows:

Due to manufacturing tolerances, the aforementioned calculation can deviate by up to +/- 20% for up to ten turns 6. The percentage increase in the winding spacing 7 in the conveying direction is greater than 1%. In the above formula, the percentage increase would be p. In addition, the increase in the winding spacing 7 shown in FIGS. 4 to 6 is between 2 to 20%. 6, the percentage increase in the winding spacing 7 is approximately 6% +/- 1%.

Fig. 1 shows that between two immediately adjacent worm shafts 3 and the immediately adjacent spirals 5 two distances and consequently two screen gaps are included. The abovementioned distances are the smallest from 9 immediately adjacent coils 5 from immediately adjacent worm shafts 3 and the distance 10 from adjacent turns 6. The distance 10 characterizes the separating grain size and can also be referred to as separating grain size distance. The distance 10 or the separation grain size distance defines the parallelogram-shaped screen gap. Another gap is of course defined by the smallest distance 9.

The smallest distance 9 and the distance 10 between adjacent turns 6 immediate bar adjacent helixes 5 of immediately adjacent worm shafts 3 increases in the conveying direction X. In the exemplary embodiment shown in FIGS. 1 to 3, the smallest distance 9 and the distance 10 increase strictly monotonously in the conveying direction X.

It is not shown that the distance 10 - consequently also the smallest distance 9 - of adjacent turns 6 of adjacent coils 5 is adjustable. Accordingly, the so-called angle of rotation offset between immediately adjacent worm shafts 3 and consequently also the respective screen gap can be set.

In Fig. 1, a drive device 1 1 is shown, which drives the worm shafts 3 with egg ner synchronous angular velocity. The drive device 1 1 is arranged on an end worm shaft 3, the device 14 facing the Beschickungseinrich. The worm shafts 3 are interconnected via connecting means, not shown, in particular gear roller chains, which each act between two immediately adjacent worm shafts 3.

The connecting means, not shown, are angeord net to the drive means 18 and cooperate with them. In the illustrated embodiments, the drive means 18 are designed as chain gears or gearwheels and are arranged on the worm shaft 3 itself. The torque is transfer means and via the drive means 18 to the core tube 4. On the worm shafts 3, two drive means 18 are provided, since on the worm shafts 3 - apart from the edge-side worm shafts 3 - two connecting means are arranged.

The spirals 5 of all worm shafts 3 have at least essentially the same web height 12. In addition, the worm shafts 3 are at least essentially of identical construction and only rotated against one another for arrangement in the holder 13.

The worm shaft 3 has a cylindrical core tube 4, as can be seen from FIGS. 4 to 6.

1 to 3, the axes of rotation 8 of the worm shafts 3 run parallel to one another. In addition, the worm shafts 3 are arranged in a horizontal plane. It is not shown that the axes of rotation 8 of the screw shafts 3 can also not run parallel to one another and / or that the screw shafts 3 are arranged in an inclined plane or curved, preferably trough-shaped. With a trough-shaped arrangement of the worm shafts 3, the conveying direction X results in each case for one worm shaft 3. A plurality of conveying directions X are therefore provided. The winding spacing 7 would consequently increase in the conveying direction X of the respective worm shaft 3 - at least one worm shaft 3 - at least in regions. In the illustrated embodiments, the worm shafts 3 are mounted on one side in a holding device 13. It is not shown that the worm shafts 3 can also be supported on both sides in a holder 13, wherein a fraction can also be ejected via the holder 13. Furthermore, it is not shown that the holder 13 with the worm shafts 3 can be tilted in at least one direction, in particular in all directions. Likewise, it is not shown that the height of the holder 13 is made adjustable. LIST OF REFERENCE NUMBERS

1 device

2 feed

3 worm shaft

4 core tube

5 coils

6 turns

7 turn spacing

8 axis of rotation

9 smallest distance

10 distance

1 1 drive device

12 bridge height

13 bracket

14 loading device

15 feed agents

16 dropping end

17 End of task

18 drive means

X direction of conveyance

Y further conveying direction

ao-a7 turn spacing

Claims

claims:

1. Device (1) for separating feed material (2) with at least two worm shafts (3), the worm shaft (3) having a core tube (4) and a spiral (in particular spiraling around the core tube (4)) ) with a plurality of turns (6), with adjacent turns (6) being spaced apart from one another by a win (7) and wherein the direction of conveyance (X) of the worm shaft (3) is at least substantially parallel to the axis of rotation (8) of the worm shaft (3) runs,

characterized,

that the winding spacing (7) of at least one worm shaft (3) increases in the conveying direction (X) at least in some areas.

2. Device according to claim 1, characterized in that the spirals (5) of immediately adjacent worm shaft (3) interlock.

3. Device according to claim 1 or 2, characterized in that at least two immediately adjacent worm shafts (3), in particular all worm shafts (3), have the same direction of rotation.

4. Device according to one of the preceding claims, characterized in that the winding spacing (7) of all screw shafts (3) in the direction of conveyance (X) increases at least in regions.

5. Device according to one of the preceding claims, characterized in that the winding spacings (7) in the conveying direction (X) increase monotonously, preferably strictly monotonously.

6. Device according to one of the preceding claims, characterized in that the percentage increase in the winding spacing (7) in the conveying direction (X) between two immediately adjacent winding spacings (7) is at least substantially the same.

7. Device according to one of the preceding claims, characterized in that the percentage increase in the winding spacing (7) in the conveying direction (X) is greater than 1%, preferably greater than or equal to 2%, preferably between 2% to 20%, more preferably between 4% to 10%, very particularly preferably between 4% to 6%.

8. Device according to one of the preceding claims, characterized in that the smallest distance (9) and / or the distance (10) adjacent

Windings (6) of immediately adjacent coils (5) of immediately adjacent worm shafts (3) rise in the conveying direction (X), in particular the smallest distance (9) and / or the distance (10) being monotonous, preferably strictly monotonous, in the conveying direction ( X) increases.

9. Device according to one of the preceding claims, characterized in that the distance (10) of adjacent turns (6) of adjacent Wen deln (5) is adjustable and / or that a drive device (1 1) is provided which the worm shafts (3rd ) drives with a synchronous angular velocity.

10. Device according to one of the preceding claims, characterized in that the coils (5) of all worm shafts (3) have at least essentially the same web height (12) and / or that the worm shafts (3) are at least essentially identical are trained.