EP3017879A1 - Screening device with filter rollers for preventing oversized particles from getting stuck - Google Patents

Abstract

Sieve device for sorting screenings into one or more fine grain fractions and one or more oversize grain fractions, the screening device comprising: (a) a frame (2, 3) and (b) a roller screen (1) with screen rolls (20, 30) supported on the frame (2, 3) and supported on the frame (2, 3) next to each other by one roller axis (R), preferably rotatably mounted at both axial ends on the frame (2, 3), each having a roller body (21; 31) and one or more screen structures (22; 32) projecting radially relative to the roller body (21; (c) wherein between the roller bodies (21; 31) of adjacent screen rollers (20; 30) there is in each case a fine grain screen gap through which a fine grain fraction falls, while during rotary drive of the screen rollers (20; 30) an oversize fraction on the roller screen (1) in the roller axial direction (X), characterized in that (d) the roll body (21; 31) of at least one of the screen rolls (20; 30) radially expands in an axial expansion section (25; 35) in the roll axis direction (X) (e) and the width (w) of the fine grain screen gap formed by the widening roller body (21; 31) with the roller body (21; 31) of an adjacent screen roller (20; 30) along the widening portion (25; 35) in the roller axial direction (X) decreases.

Description

The invention relates to a screening device with screen rollers, which are arranged side by side rotatably drivable on a frame to form a roller screen for sorting screenings in one or more fine grain fractions and one or more oversized grain fractions. The screen rollers are adapted to convey at least a portion of an oversize fraction in roll axis direction. The invention further relates to a screen roller suitable for forming such a screening device as such.

A screening device of the type mentioned is for example from the EP 1 570 919 B1 known. The screening device comprises a roller screen with juxtaposed rotationally drivable arranged, intermeshing screw or spiral rollers. A screened material placed on the roller screen is separated into a fine grain fraction falling between these screen rollers, a first oversize grain fraction conveyed onto the screen rolls transversely to the roll axis direction, and a second oversize grain fraction conveyed in the roll axis direction by screwing action of the screen rolls. The first oversize fraction is discharged at one end of the roller screen transversely to the roller axis direction. The screen rollers are mounted only at one end and thus on the fly, so that the second oversize grain fraction can be discharged unhindered at the freely projecting end of the screen rollers.

The EP 2 329 891 B1 describes another example of a screening device. Instead of helical or spiral rollers, the screening device has screen rollers with roller axes in parallel juxtaposed screen discs, which together form a disc screen. However, in order to convey a portion of the oversize grain fraction in the roll axis direction, the screen rolls of the screen screen are arranged such that the roll axes are inclined obliquely downward from a feed region of the screen screen toward an output region. The relevant oversize fraction is therefore conveyed by gravity in Walzenachsrichtung. In contrast to the first-mentioned screening device, the screen rollers of the screen screen are mounted on both sides, so that precautions must be taken so as not to unduly obstruct the removal of the relevant oversize fraction beyond the axial ends of the screen rollers.

It is an object of the invention to reduce the risk of jamming of parts of this oversize fraction in a roller screen on which a Überkornfraktion is promoted in Walzenachsrichtung, especially in embodiments in which screen rollers of the roller screen are mounted on both sides. It is also an object to provide a screen roll which, when installed in a roller screen counteracts in particular in the case of a two-sided storage of the risk of jamming by promoted in Walzenachsrichtung oversize.

The invention is based on a screening device for sorting screenings into one or more fine-grain fractions and one or more oversize fractions, comprising a frame and a roller screen with screen rolls arranged side by side about a respective roll axis and supported on the frame. The screen rollers each have a roller body and one or more relative to the roller body radially projecting screen structures. The screen rollers are designed and arranged such that between the roller bodies of adjacent screen rollers there is in each case a fine-grain screen gap through which a fine-grain fraction falls, while an oversize-grain fraction is conveyed on the roller screen in the direction of the roller axis when the screen rollers are rotated.

The one or more radially projecting screen structures of the respective screen roller may be screen discs, in particular screen stars with radially projecting star fingers. Screen discs of this kind are for example from the EP 1 088 599 B1 known. The protruding fingers of the individual screen stars can advantageously be elastically yielding as described in this document, but in principle the screen stars can also be unyielding in their intrinsic properties or have a negligible elasticity in practical operation. In order to promote an oversize fraction in Walzenachsrichtung, the screen discs of the screen rollers of a Scheibensiebs be inclined with respect to the respective roll axis, ie in plan view of the roller screen to the respective roll axis an inclination greater than 0 ° and less than 90 ° to the respective oversize fraction To promote screwing in Walzenachsrichtung. Instead of screen stars also simple circular or oval or similarly shaped screen discs can be used. In principle, the screen discs of any kind can also be arranged orthogonal to the respective roller axis. In designs with only orthogonally oriented screen disks or other screen structures, the screen rollers are inclined downwards in the roller axis direction into which the oversized grain fraction in question is to be conveyed in order to effect gravity conveyance.

In preferred embodiments, however, the screen rollers or at least a part of the screen rollers of the roller screen are screw or spiral rollers and each have a screen structure radially projecting over the roller body in the form of a helical structure running helically around the roller axis. In such embodiments, two or possibly even more helically rotating screen structures can rotate around the same roller body, which together form a multi-layer screen structure of the respective screen roller. Appropriately, however, the screen rollers each have only a single screw-like circumferential screen structure, so are catchy. A screen structure formed as a helical structure advantageously proceeds continuously the roll axis in question so that its course over the entire axial length or at least the vast majority of the length of the screen structure is mathematically expressed continuously differentiable.

The one or more screen structures of adjacent screen rollers protruding radially with respect to the respective roller body advantageously engage one another in a plan view of the roller screen. As seen in plan view, the screen structures thus protrude into the fine grain sieve gaps formed between adjacent roll bodies through which the fine grain falls, followed by a protruding screen structure or a protruding screen structure section of an adjacent screen roller in a roll axis direction onto a protruding screen structure or a protruding screen structure section of one screen roller. In principle, however, it would also be possible not to arrange the screen structures of adjacent screen rolls in roll axis direction "gap" so that they intermesh with one another in a comb-like manner, but to form them so that they face axially at the same height and thus directly in the transverse direction. However, the intermeshing of screen structures of adjacent screen rolls gives rise to constructive freedom with regard to the design of the "mesh width" of the wire screen in addition to the dimensioning of the gap width between the roller bodies.

According to the invention, the roll body of at least one of the screen rolls widens radially in an axial expansion section in the roll axis direction so that the width of the fine wire screen gap which the expanding roll body forms with the roll body of an adjacent screen roll decreases in the expansion section in the roll axis direction. The roller axis direction is the direction in which the relevant oversize grain fraction is conveyed to the widening section. While elongated and light parts of the oversized grain fraction are primarily conveyed transversely to the roll axis direction, the oversized grain fraction conveyed in the roll axis direction mainly contains pieces which are compact and heavy in terms of their external dimensions. If the screenings are, for example, excavated earth or construction debris, the oversized grain fraction conveyed in the roll axis direction contains caked earth clods and / or larger stones which do not fall down through the wire screen, but because of their dimensions and their weight in the troughs formed between adjacent screen rolls Roll axis direction to be promoted. This oversize fraction is caused to float in the expansion section, ie by the rolling body which widens there, since the parts concerned can protrude less deeply into the fine-grained screen gap narrowing due to the expansion. The groove formed over the fine-grain screen gap with an adjacent roller body becomes flatter and the conveying action of the screen roller in the circumferential direction, transverse to the roller axis direction, becomes stronger. If the one or more protruding screen structures have an inclination relative to the roller axis direction and therefore exert a conveying effect on the oversize in the roller axis direction, this axial conveying effect, on the other hand, weakens along the widening section.

Because of the increased cross-promotion in the area of widening even of compact oversize and concomitantly reducing the risk of jamming, they can be stored at both ends in a roller screen with expanding screen rollers, which benefits the stability and robustness of the screening device. A frame wall may limit the roller screen at the downstream ends of the screen rollers, which offers advantages in many applications or facilitates the installation of the roller screen.

The screen roller can also have in the expansion section one or more screen structures projecting radially with respect to the roller body, for example one or more screen disks or preferably a section of a helically revolving, ie helical screen structure. In principle, a helical screen structure can extend up to an axial axial end of the expansion section in the direction of the roll axis or a screen disk can be arranged at this end. However, in preferred embodiments, the amount of radial protrusion, the height, of the one or more screen structures in the flare section decreases, i. H. the one or more screen structures flat in Aufweitabschnitt in Walzenachsrichtung. If one thinks of an envelope applied to the outer circumference of the one or more screen structures, a virtual envelope, then this envelope tapers in the preferred embodiments in the expansion section in the roll axis direction. The radial height of the flanks, with which the one or more screen structures in roll axis direction produce a conveying effect, if it is inclined to the Walzenachsrichtung, thereby decreases not only due to the expansion of the roll body, but additionally by the radial flattening of the one or more screen structures , The already achieved by the expansion of the roll body effect of floating is enhanced and further attenuated any axial conveying effect.

The roll body can in particular expand conically in the expansion section. Instead of widening with a constant widening angle, the roll body in the widening section can also expand in a trumpet shape, ie with increasing widening angle and thus progressively, or bell-shaped, ie with decreasing widening angle or degressive. Although the expansion may take place discontinuously, in stages, and in this case preferably in several small stages, embodiments are preferred in which the roll body widens gradually and continuously in the expansion section, mathematically speaking, continuously differentiable and preferably monotonous. The expansion extends over a section length which is larger in preferred embodiments, preferably at least twice and more preferably at least five times greater than the gap width of the fine-grain screen gap which the roller body forms in the roll axis direction in front of the expansion section with an adjacent roller body of the roller screen.

The roll body expands in Aufweitabschnitt up to a maximum width. The largest width is preferably at most as large as a maximum radial width of the one or more screen structures, which is or are arranged with respect to the Walzenachsrichtung before the Aufweitabschnitt. More preferably, the largest radial width that the roll body has in the expansion section is smaller than the largest radial width of the outer periphery of this one or more screen structures that are upwardly with respect to the roll axis direction. The one or more upward screen structures preferably have a constant width over the length of an upright roll body portion to which the expansion portion in the roll axis direction adjoins, so that said envelope is cylindrical in the upstream roll body portion.

The roll body can expand continuously in the expansion section from an initial width to a largest radial width, that is to say be conical, trumpet-shaped or bell-shaped over the entire axial length of the expansion section, with a monotonously increasing width. In preferred embodiments, however, the expansion section has a first subsection and, immediately thereafter, a second subsection. In the first axial subsection, the roller body widens, preferably as already described, until it has a greatest radial width at an axial end of the first subsection. Preferably, the radial width in the second subsection is at least substantially constant, wherein the radial width of the second subsection may correspond in particular to the greatest radial width of the first subsection. In the second subsection, the roller body is preferably at least substantially cylindrical. A cylindrical second subsection may in particular be circular-cylindrical.

In preferred embodiments, the roll body in the expansion section has a transverse conveyor structure or a return conveyor structure, which also includes the combination of a transverse and return conveyor structure. Due to the widening and consequent floating on the reached in the Aufweitabschnitt oversize grain already exerted in comparison to the roll body before the expansion section promoted transverse to the roll axis direction. By a transverse conveying structure, this cross-conveying effect is enhanced in the expansion section. The transverse conveying structure may in particular be formed in the form of a surface structuring, such as a knurling or corrugation, or an external toothing or rib structure with protruding, axially extended teeth or ribs. The conveying structure may be further developed into a transverse and return conveying structure in order to be able to exert not only an increased conveying action in the circumferential direction of the screen roller but also against the roller axis direction on oversize particles which have reached the expanding section. A transverse and Rückförderstruktur can also be advantageously formed in the manner of an external toothing or rib structure with teeth or ribs, with respect to the Roll axis have an inclination greater than 0 ° and less than 90 °. Thus, for example, a helical gearing or a rib structure with ribs which extend at an angle on the circumference of the widening section can form the transverse and return conveying structure. If the roll body in the expansion section has the subsections already explained, which differ from one another with respect to the widening, the transverse and / or return structure is preferably provided in the second subsection, preferably only in the second subsection.

In first embodiments, the expansion section forms an axial conveying end of the screen roller, wherein the roller body preferably has a greatest radial width at this conveying end. The axial conveying end is one end of the screen roller, which can not be conveyed either axially due to a limitation or leaves the roller screen on the oversize conveyed in the roller axis direction and in particular can fall from the roller screen between the screen rollers.

The frame in preferred embodiments comprises a frame wall defining the roller screen at one axial end of the screen rollers and projecting beyond the top of the roller screen. The axial conveying ends of the screen rollers can face this frame wall axially. The roller screen therefore conveys the relevant oversize grain in the roll axis direction onto the frame wall. If the oversize is conveyed in roll axis direction up to the frame wall, there is the risk of clogging or jamming at the axial conveyor end. This danger is counteracted in the first embodiments by the widening of the roller body at the conveyor end, since the oversize floats in the widening section and undergoes increased transverse conveyance through the rotating roller body in the widening section, which can be reinforced by forming the aforementioned transverse and / or return structure.

In a preferred variant of the first embodiments, the roller bodies are diluted at least at a part of the screen rollers on the frame wall near the axial end or end at a distance in front of the frame wall. The respective screen rollers each have a slender roller section immediately in front of the frame wall. The width of the gaps obtained in the region of the slender roller sections between adjacent screen rollers is greater than the width of the fine-wire screen gap. In this way, at the ends of the screen rollers, which are downwards in relation to the roller axis direction, an edge strip is produced, in which oversize particles conveyed up to the edge strips can fall through between adjacent screen rollers. The distance between the axial conveying end of the respective screen roller and the facing opposite frame wall is expediently at least as large as a width measured transversely to the roller axis direction of the oversize grain conveyed on the roller screen at least primarily in the roll axis direction. The distance that the axial conveying end of the screen roller from the axially facing frame wall, is preferably at least twice, more preferably at least three times as large as the width of the fine-mesh screen gap formed by the screen roller with the adjacent screen roller for the fine-grain fraction falling through the roller screen, upwardly from the expanding section. In the slender from the axial conveyor end to the facing frame wall roller section, the screen roller has a maximum radial width, preferably a constant over the entire section maximum radial width, which is in preferred embodiments at most half as large as the radial width of the roller section, with the Screening roller forms the Feinkornsiebspalt through which the fine grain fraction falls upstream of the Aufweitabschnitt therethrough. Although in principle one or more screen rollers of the roller screen with the full width of the respective roller body or with its expansion section to directly to said frame wall can extend or may, it is preferred if all screen rollers of the roller screen, which extend axially to the frame wall, a As described slender roll section in front of the frame wall, so that immediately in front of the frame wall in the transverse direction continuously continuous edge strip is obtained, in which the promoted in Walzenachsrichtung oversize grain fraction can fall down. Preferably, a conveying means, such as a belt conveyor, is arranged under the edge strip, whereupon the oversize grain fraction can fall and be conveyed away.

In second embodiments, the roll body has an axially upwardly extending roll body portion and an axially downward roll body portion and the expansion portion axially between the upstream and downstream roll body portions with respect to the roll axis direction. The widening forms in the second embodiments, no axial conveying end of the roller body, but a central portion. The length of the axially upwardly extending roll body portion may be the same or substantially as long as the length of the axially downward roll body portion. The lengths of these two sections may, however, also differ significantly from each other. In the second embodiment, the screen roller may have only a single expansion section or, in further developments, a further expansion section. In the further expansion section, the roller body can expand, in particular, against the roller axis direction. However, embodiments in which the roller body expands in the further expansion section into the roller axis direction should not be excluded. In particular, in embodiments in which the roll body expands in the further expansion section against the Walzenachsrichtung, it is further preferred if the two Aufweitabschnitte adjacent to each other, so that in Walzenachsrichtung an expansion and then a taper is obtained. Preferably, the expansion sections, each having a greatest radial width, adjoin one another. The remarks made on the expansion section are preferably equally applicable to the further expansion section.

In the second embodiments, in which the screen roller has the expansion section axially between an upwardly and downwardly directed roller body section, it is advantageous if the one or more protruding screen structures have an inclination of greater than 0 ° and less than 90 ° in radial views of the screen roller relative to the roller axis direction and the inclination in the up-facing roll body section is positive to or into the expansion section and negative in the downstream roll body section. During the rotary drive of the screen roller, the axially conveyed oversized grain fraction is conveyed from two sides of the screen roller in each case in the direction of the expanding section. Preferably, the screen roller in training for axially opposing promotion on the other, against the Walzenachsrichtung widening Aufweitabschnitt so that not only promoted in Walzenachsrichtung to Aufweitabschnitt oversize fraction in Aufweitabschnitt, but also from the other side against the Walzenachsrichtung promoted oversize fraction in the further Aufweitabschnitt floats and is conveyed in the transverse direction in the area of the two expansion sections. A discharge is, however, in principle already then effected when the screen roller over the entire length of the roller body is set up only for a promotion in Walzenachsrichtung, since in such embodiments, at least a portion of the axially conveyed oversized grain fraction floats in Aufweitabschnitt and there transverse to Walzenachsrichtung and only one remaining part of the oversize fraction is conveyed axially over the Aufweitabschnitt away in the downstream roll body portion.

In order to reduce forces acting on the respective screen roller by jamming screen material, the roller body of at least one of the screen rollers, in particular of the roller body having the expansion section, can be mounted so as to be axially movable, ie axially floating. Preferably, the relevant roller body is axially movable against the restoring force of an elastic element. This includes embodiments in which the respective screen roller is mounted as a whole axially movable or floating and in particular embodiments in which the roller body is mounted axially floating on a rotatably mounted shaft of the screen roller. Namely, in preferred embodiments, the screen rollers each have a comparatively slender shaft which is rotatably supported by the frame, preferably at both shaft ends, and in each case a roller body which is joined torque-tight with the shaft, preferably rotationally immovable. In such embodiments, preferably, the roller body is mounted axially movable relative to the shaft of the respective screen roller, for example by means of an elastic element at one axial end or one elastic element at both axial ends of the roller body. The extent of axial mobility is typically in the range of a few millimeters, in many embodiments, the extent of axial mobility is between 1 and 3 mm. The elastic element may in particular be an elastomeric element or a natural rubber element. In principle, however, a spring can also form the element.

In expedient embodiments, the roller screen has a plurality of screen rollers of the type according to the invention. For these screen rolls, the comments made to the at least one screen roller apply equally. Thus, as seen in plan view, for example, every other screen roller may be a screen roller of the type according to the invention, more preferably the roller screen comprises screen rollers of the type according to the invention, which are arranged directly next to each other. Conveniently, all or at least the majority of the screen rollers of the roller screen are formed according to the invention.

The roll body is expediently rotationally symmetrical, preferably also in the expansion section. In such embodiments, it comprises one or more circular-cylindrical roller body sections and one or more rotationally symmetrical expansion sections. The roll body is advantageously a uniform, inherently rigid body of revolution, d. H. it can be considered as consisting of a single piece. For practical reasons, however, it may be composed of a plurality of roll body sections, for example one or more cylindrical roll body sections and one or more expansion sections.

The screen rollers can be arranged horizontally at the same height next to each other, so that the roller screen as a whole forms a horizontal plane. In modifications, the roller screen in the transverse conveying direction with a constant slope or constant slope inclined or inclined in the transverse conveying direction upward or fall down by two or more of the screen rollers are arranged according to different heights side by side. The roller screen as a whole can also form a trough by arranging one or more screen rollers located on the sides of the roller screen with respect to the transverse conveying direction higher than one or more screen rollers in the center of the screen. In a further modification, the screen rolls may be arranged inclined in the roll axis direction, preferably rising in the roll axis direction. When promoting the compact oversize in Walzenachsrichtung and against gravity also the risk of jamming is reduced. Furthermore, clumping materials, such as loamy earth excavation, loosened up, as the lumps undergo increased shocks due to gravity and also remain longer on the roller screen.

However, the invention relates not only to the screening device with the roller screen, but also a screen roller of the type according to the invention as such. The screen roller according to the invention has a roller body with an outer roller body circumference, at least one axial end of a bearing journal for pivotal mounting of the roller body about a roller axis and one or more with the roller body torque transmitting, preferably drehunbeweglich connected over the roller body circumference radially projecting sieve structures. As already described, the one or more screen structures of the screen roller one or more to the Roll body circumference helically encircling helix structure (s) or a plurality of axially spaced apart screen disks, such as screen stars, be. According to the invention, the roll body circumference widens radially in an axial expansion section in the roll axis direction. As far as previously a screen roller was described only in connection with the screening device, the statements made for the screen roller of the screening device apply in the same way for the screen roller according to the invention as such, at least as far as features of the screen roller are concerned as such.

Advantageous features are also described in the subclaims and the combinations of the subclaims.

• Aspekt 1. Siebvorrichtung zum Sortieren von Siebgut in eine oder mehrere Feinkornfraktionen und eine oder mehrere Überkornfraktionen, die Siebvorrichtung umfassend:
  1. (a) ein Gestell (2, 3) und
  2. (b) ein Walzensieb (1) mit nebeneinander um jeweils eine Walzenachse (R) drehantreibbar angeordneten, am Gestell (2, 3) abgestützten Siebwalzen (20; 30), die jeweils einen Walzenkörper (21; 31) und eine oder mehrere relativ zum Walzenkörper (21; 31) radial vorstehende Siebstrukturen (22; 32) aufweisen,
  3. (c) wobei zwischen den Walzenkörpern (21; 31) benachbarter Siebwalzen (20; 30) jeweils ein Feinkornsiebspalt besteht, durch den eine Feinkornfraktion fällt, während bei Drehantrieb der Siebwalzen (20; 30) eine Überkornfraktion auf dem Walzensieb (1) in Walzenachsrichtung (X) gefördert wird,
     dadurch gekennzeichnet, dass
  4. (d) sich der Walzenkörper (21; 31) wenigstens einer der Siebwalzen (20; 30) in einem axialen Aufweitabschnitt (25; 35) in Walzenachsrichtung (X) radial aufweitet
  5. (e) und die Weite (w) des Feinkornsiebspalts, den der sich aufweitende Walzenkörper (21; 31) mit dem Walzenkörper (21; 31) einer benachbarten Siebwalze (20; 30) bildet, längs des Aufweitabschnitts (25; 35) in Walzenachsrichtung (X) abnimmt.
• Aspekt 2. Siebvorrichtung nach dem vorhergehenden Aspekt, wobei sich eine virtuelle Umhüllende (H), die an den äußeren Umfang der einen oder mehreren Siebstrukturen (22; 32) der wenigstens einen den Aufweitabschnitt (25; 35) aufweisenden Siebwalze (20; 30) angelegt ist, längs des Aufweitabschnitts (25; 35) in Walzenachsrichtung (X) verjüngt.
• Aspekt 3. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei die Siebwalze (20; 30) auch im Aufweitabschnitt (25; 35) eine oder mehrere über den Walzenkörper (21; 31) radial vorstehende Siebstrukturen (22; 32) aufweist.
• Aspekt 4. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei sich der Aufweitabschnitt (25; 35) in einem ersten Unterabschnitt (26; 36) in Walzenachsrichtung (X) über eine Länge (a) allmählich, vorzugsweise monoton und kontinuierlich, bis auf eine größte Weite aufweitet und in einem zweiten Unterabschnitt (27; 37), der sich in Walzenachsrichtung (X) an den ersten Unterabschnitt (26; 36) anschließt, zumindest im Wesentlichen zylindrisch ist, vorzugsweise mit der größten Weite.
• Aspekt 5. Siebvorrichtung nach dem vorhergehenden Aspekt, wobei die Länge (a) des Aufweitens größer als die Weite (w) des Feinkornsiebspalts ist, den der Walzenkörper (21; 31) bezüglich der Walzenachsrichtung (X) aufwärts vom Aufweitabschnitt (25; 35) mit einer benachbarten Siebwalze (10; 20; 30) bildet.
• Aspekt 6. Siebvorrichtung nach einem der zwei unmittelbar vorhergehenden Aspekte, wobei die Länge (a) des Aufweitens wenigstens mehrere Zentimeter beträgt.
• Aspekt 7. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei sich der Aufweitabschnitt (25; 35) in einem ersten Unterabschnitt (26; 36) in Walzenachsrichtung (X) aufweitet, vorzugsweise monoton und kontinuierlich und vorzugsweise bis auf eine größte Weite, und in einem zweiten Unterabschnitt (27; 37), der sich in Walzenachsrichtung (X) an den ersten Unterabschnitt (26; 36) anschließt, eine größte Weite aufweist, vorzugsweise zumindest im Wesentlichen zylindrisch ist, und wobei sich die eine oder mehreren vorstehenden Siebstrukturen (22; 32) in Walzenachsrichtung (X) bis maximal zu dem zweiten Unterabschnitt (27; 37), vorzugsweise in den ersten Unterabschnitt (26; 36), erstreckt oder erstrecken.
• Aspekt 8. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei der Walzenkörper (21; 31) im Aufweitabschnitt (25; 35), vorzugsweise im zweiten Unterabschnitt (27; 37) nach einem der zwei direkt vorhergehenden Aspekte, am äußeren Umfang eine Quer- und/oder Rückförderstruktur (28; 38), vorzugsweise eine Oberflächenstrukturierung oder eine Zahn- oder Rippenstruktur mit axial geraden oder unter einer Neigung zur Walzenachsrichtung (X) erstreckten Zähnen oder Rippen, aufweist, um auf in den Aufweitabschnitt (25; 35) gefördertes Überkorn eine quer zur Walzenachsrichtung (X) und/oder gegen die Walzenachsrichtung (X) gerichtete Förderwirkung auszuüben.
• Aspekt 9. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei sich der Walzenkörper (21; 31) im Aufweitabschnitt (25; 35) über eine Länge (a) von wenigstens mehreren Zentimetern stetig differenzierbar aufweitet.
• Aspekt 10. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei sich der Walzenkörper (21; 31) im Aufweitabschnitt (25; 35) über eine Länge (a) von wenigstens mehreren Zentimetern konisch, trompetenförmig oder glockenförmig aufweitet.
• Aspekt 11. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei die eine oder mehreren Siebstrukturen (22; 32) in Draufsicht auf das Walzensieb (1) zur Walzenachsrichtung (X) eine Neigung (α) von größer 0° und kleiner 90° aufweisen, um bei Drehantrieb der Siebwalzen (20; 30) zumindest einen Teil der Überkornfraktion in die Walzenachsrichtung (X) zu fördern.
• Aspekt 12. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei der den Aufweitabschnitt (25; 35) aufweisende Walzenkörper (21; 31) axial beweglich ist, vorzugsweise gegen die Rückstellkraft eines elastischen Elements (15).
• Aspekt 13. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei an wenigstens einer der Stirnseiten des den Aufweitabschnitt (25; 35) aufweisenden Walzenkörpers (21; 31) ein axial elastisches Element (15) angeordnet und der Walzenkörper (21; 31) gegen die Rückstellkraft des elastischen Elements (15) axial beweglich ist.
• Aspekt 14. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei die Siebwalzen (20; 30) an beiden axialen Enden am Gestell (2, 3) drehbar gelagert sind.
• Aspekt 15. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei an einem in Walzenachsrichtung (X) abwärtigen Ende der Siebwalzen (10; 20) eine Gestellwand (3) über eine Oberseite des Walzensiebs (1) hinaus aufragt und wenigstens ein Teil der Walzenkörper (11; 21) an den der Gestellwand (3) zugewandten Enden verdünnt sind oder in einem axialen Abstand vor der Gestellwand (3) enden, so dass die Siebwalzen (10; 20) an den der Gestellwand (3) zugewandten Enden jeweils einen schlanken Walzenabschnitt (14) aufweisen, und der lichte Abstand zwischen jeweils benachbarten schlanken Walzenabschnitten (14) wenigstens doppelt, vorzugsweise wenigstens dreimal so groß wie eine größte Weite (w) des Feinkornsiebspalts zwischen benachbarten Walzenkörpern (11; 21) ist, so dass die schlanken Walzenabschnitte (14) einen quer zur Walzenachsrichtung (X) erstreckten und an die Gestellwand (3) grenzenden Randstreifen (8) bilden, in dem bis in den Randstreifen (8) gefördertes Überkorn zwischen den Siebwalzen (10; 20) hindurch fallen kann.
• Aspekt 16. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei der Walzenkörper (31) einen weiteren Aufweitabschnitt (35') aufweist und sich im weiteren Aufweitabschnitt (35') entweder ebenfalls in oder vorzugsweise gegen die Walzenachsrichtung (X) aufweitet.
• Aspekt 17. Siebvorrichtung nach dem vorhergehenden Aspekt, wobei die Aufweitabschnitte (35, 35') gemeinsam einen zusammenhängenden Aufweitabschnitt bilden, in dem sich der Walzenkörper (31) in die Walzenachsrichtung (X) aufweitet und anschließend wieder verjüngt.
• Aspekt 18. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei der Aufweitabschnitt (25) ein axiales Förderende der wenigstens einen Siebwalze (20) bildet, vorzugsweise am Förderende eine größte Weite aufweist.
• Aspekt 19. Siebvorrichtung nach einem der Aspekte 1 bis 17, wobei der Walzenkörper (31) in Bezug auf die Walzenachsrichtung (X) einen aufwärtigen Walzenkörperabschnitt (31a) und einen abwärtigen Walzenkörperabschnitt (31b) und den Aufweitabschnitt (35) axial zwischen dem aufwärtigen und dem abwärtigen Walzenkörperabschnitt aufweist.
• Aspekt 20. Siebvorrichtung nach dem vorhergehenden Aspekt, wobei die eine oder mehreren vorstehenden Siebstrukturen (32) der wenigstens einen den Aufweitabschnitt (25; 35) aufweisenden Siebwalze (20; 30) in Draufsicht auf das Walzensieb (1) zur Walzenachsrichtung (X) eine Neigung (α) von größer 0° und kleiner 90° aufweisen und die Neigung (α) im aufwärtigen Walzenkörperabschnitt (31a) bis zum oder in den Aufweitabschnitt (35) positiv und im abwärtigen Walzenkörperabschnitt (31b) bis maximal zum Aufweitabschnitt (25; 35), vorzugsweise bis zum oder in den weiteren Aufweitabschnitt (35') des Aspekts 17, negativ ist, um bei Drehantrieb der Siebwalze (30) zumindest einen ersten Teil der Überkornfraktion in Walzenachsrichtung (X) und zumindest einen zweiten Teil der Überkornfraktion gegen die Walzenachsrichtung (X) zu fördern und im Bereich des Aufweitabschnitts (35), vorzugsweise im Bereich der Aufweitabschnitte (35, 35') des Aspekts 17, quer zur Walzenachsrichtung (X) abzufördern.
• Aspekt 21. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei das Walzensieb (1) mehrere Siebwalzen (20; 30) aufweist, die jeweils wenigstens einem der vorhergehenden Aspekte entsprechen.
• Aspekt 22. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei in Draufsicht auf das Walzensieb (1) wenigstens jede zweite der Siebwalzen (20; 30) jeweils wenigstens einem der vorhergehenden Aspekte entspricht.
• Aspekt 23. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei in Draufsicht zwei oder mehr unmittelbar nebeneinander angeordnete Siebwalzen (20; 30) des Walzensiebs (1) jeweils wenigstens einem der vorhergehenden Aspekte entsprechen und die Aufweitabschnitte (25; 35) benachbarter Siebwalzen (20; 30) nebeneinander angeordnet sind und sich in die gleiche Richtung aufweiten, so dass sich die Weite (w) des Feinkornsiebspalts zwischen den benachbarten Aufweitabschnitten (25; 35) von beiden Seiten verringert, vorzugsweise symmetrisch.
• Aspekt 24. Siebvorrichtung nach einem der drei unmittelbar vorhergehenden Aspekte, wobei die Aufweitabschnitte (25; 35, 35') der Siebwalzen (20; 30) so angeordnet sind, vorzugsweise in Walzenachsrichtung (X) auf gleicher Höhe nebeneinander, dass sie in Draufsicht auf das Walzensieb (1) gemeinsam einen geraden, zur Walzenachsrichtung (X) schrägen oder vorzugsweise orthogonalen Streifen von Aufweitabschnitten (25; 35, 35') bilden.
• Aspekt 25. Siebvorrichtung zum Sortieren von Siebgut in eine oder mehrere Feinkornfraktionen und eine oder mehrere Überkornfraktionen, vorzugsweise nach einem der vorhergehenden Aspekte, die Siebvorrichtung umfassend:
  1. (a) ein Gestell (2, 3) mit einer Gestellwand (3) und
  2. (b) ein Walzensieb (1) mit nebeneinander um jeweils eine Walzenachse (R) drehantreibbar angeordneten, am Gestell (2, 3) abgestützten Siebwalzen (20; 30), die jeweils einen Walzenkörper (21; 31) und eine oder mehrere relativ zum Walzenkörper (21; 31) radial vorstehende Siebstrukturen (22; 32) aufweisen,
  3. (c) so dass zwischen den Walzenkörpern (21; 31) benachbarter Siebwalzen (20; 30) jeweils ein Feinkornsiebspalt besteht, durch den eine Feinkornfraktion fällt, während bei Drehantrieb der Siebwalzen (20; 30) zumindest eine Überkornfraktion auf dem Walzensieb (1) in Walzenachsrichtung (X) auf die Gestellwand (3) zu gefördert wird,
  4. (d) wobei die Siebwalzen (20; 30) an beiden axialen Enden am Gestell (2, 3) drehbar gelagert sind und die Gestellwand (3) das Walzensieb (1) an einem in Bezug auf die Walzenachsrichtung (X) abwärtigen Ende begrenzt und über eine Oberseite des Walzensiebs (1) hinaus aufragt, so dass in Walzenachsrichtung (X) kein Überkorn über die Gestellwand (3) gefördert werden kann,
  5. (e) und wobei wenigstens ein Teil der Walzenkörper (21) an den aufwärtigen Enden verdünnt sind oder in einem axialen Abstand vor der Gestellwand (3) enden, so dass die Siebwalzen (10; 20) an den der Gestellwand (3) zugewandten Enden jeweils einen schlanken Walzenabschnitt (14) aufweisen, und der lichte Abstand zwischen jeweils benachbarten schlanken Walzenabschnitten (14) wenigstens doppelt, vorzugsweise wenigstens dreimal so groß wie eine größte Weite (w) des Feinkornsiebspalts zwischen benachbarten Walzenkörpern (11; 21) ist, so dass die schlanken Walzenabschnitte (14) einen quer zur Walzenachsrichtung (X) erstreckten und an die Gestellwand (3) grenzenden Randstreifen (8) bilden, in dem bis in den Randstreifen (8) gefördertes Überkorn zwischen den Siebwalzen (10; 20) hindurch fallen kann.
  Eine Siebvorrichtung gemäß Aspekt 25 kann eine oder mehrere Siebwalzen jeweils mit einem Aufweitabschnitt der erfindungsgemäßen Art aufweisen, insbesondere eine oder mehrere Siebwalzen jeweils mit einem Aufweitabschnitt, der sich nur in die Walzenachsrichtung aufweitet, wobei der Aufweitabschnitt bevorzugt das dem Randstreifen nahe axiale Förderende der jeweiligen Siebwalze bildet. Die Siebvorrichtung gemäß Aspekt 25 ist wegen des der Abförderung dienenden Randstreifens aber auch als solche, ohne den Aspekt der Aufweitung, von Vorteil, insbesondere in Anwendungen, in denen das Walzensieb von Gestellwänden an beiden axialen Enden der Siebwalzen eingerahmt ist.
• Aspekt 26. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei die eine oder mehreren Siebstrukturen (22; 32) schraubenförmig um die Drehachse (R) der jeweiligen Siebwalze (10; 20; 30) umlaufen.
• Aspekt 27. Siebvorrichtung nach einem der vorhergehenden Aspekte, wobei die eine oder mehreren Siebstrukturen (22; 32) benachbarter Siebwalzen (10; 20; 30) in Draufsicht auf das Walzensieb (1) axial zueinander versetzt sind und die jeweils benachbarten Siebwalzen (10; 20; 30) in der Draufsicht mit ihren vorstehenden Siebstrukturen (12; 22; 32) ineinander greifen.
• Aspekt 28. Siebwalze für eine Siebvorrichtung zum Sortieren von Siebgut in eine Feinkornfraktion und eine Überkornfraktion, vorzugsweise für die Siebvorrichtung nach einem der vorhergehenden Aspekte, die Siebwalze umfassend:
  • (a) einen Walzenkörper (21; 31) mit einem äußeren Walzenkörperumfang,
  • (b) einen Lagerzapfen (23; 33) zur Drehlagerung des Walzenkörpers (21; 31) um eine Drehachse (R)
  • (c) und eine oder mehrere mit dem Walzenkörper (21; 31) Drehmoment übertragend verbundene, über den Walzenkörperumfang radial vorstehende Siebstrukturen (22; 32), die von einer um den Walzenkörperumfang schraubenförmig umlaufenden Wendelstruktur oder mehreren axial voneinander beabstandeten Siebscheiben gebildet wird oder werden,
  • (d) wobei sich der Walzenkörperumfang in einem axialen Aufweitabschnitt (25; 35) in Walzenachsrichtung (X) radial aufweitet.
• Aspekt 29. Siebwalze nach dem vorhergehenden Aspekt, wobei die Siebwalze (20; 30) jedes beliebige Merkmal aufweisen kann, das in einem der auf die Siebvorrichtung gerichteten Aspekte für die wenigstens eine den Aufweitabschnitt (25; 35) aufweisende Siebwalze (20; 30) beschrieben wird.

Also in the aspects formulated below, features of the invention will be described. The aspects are formulated in the nature of claims and can replace them. Features disclosed in the aspects may further supplement and / or relativise the claims, show alternatives to individual features, and / or extend claim features. In parenthesized reference numerals refer to an embodiment illustrated below in figures. They do not limit the features described in the aspects in the literal sense as such, but on the other hand show preferred possibilities of realizing the respective feature.

• Aspect 1. Screening device for sorting screenings into one or more fine grain fractions and one or more oversize grain fractions, the screening device comprising:
  1. (a) a frame (2, 3) and
  2. (b) a roller screen (1) with screen rollers (20; 30) supported on the frame (2, 3) and supported on the frame (2, 3), each one a roller body (21, 31) and one or more relative to Roller bodies (21, 31) have radially protruding screen structures (22, 32),
  3. (c) wherein between the roller bodies (21; 31) of adjacent screen rollers (20; 30) there is in each case a fine grain screen gap through which a fine grain fraction falls, while during rotary drive of the screen rollers (20; 30) an oversize fraction on the roller screen (1) in the roller axial direction (X) is promoted,
     characterized in that
  4. (d) the roll body (21; 31) of at least one of the screen rolls (20; 30) radially expands in an axial expansion section (25; 35) in the roll axis direction (X)
  5. (e) and the width (w) of the fine grain screen gap formed by the widening roller body (21; 31) with the roller body (21; 31) of an adjacent screen roller (20; 30) along the widening portion (25; 35) in the roller axial direction (X) decreases.
• Aspect 2. A sifting apparatus according to the preceding aspect, wherein there is a virtual wrapper (H) attached to the outer circumference of the one or more screen structures (22; 32) of the at least one screen roll (20; 30) having the widening portion (25; is applied, along the Aufweitabschnitts (25; 35) in Walzenachsrichtung (X) tapers.
• Aspect 3. A screening device according to one of the preceding aspects, wherein the screen roller (20; 30) also has in the expansion section (25; 35) one or more screen structures (22; 32) radially projecting over the roller body (21;
• Aspect 4. A screening device according to one of the preceding aspects, wherein the expansion section (25; 35) in a first subsection (26; 36) in the roll axis direction (X) over a length (a) gradually, preferably monotonically and continuously, except for a largest Width widens and in a second subsection (27, 37), which adjoins the first subsection (26, 36) in roll axis direction (X), is at least substantially cylindrical, preferably with the greatest width.
• Aspect 5. A sifting apparatus according to the preceding aspect, wherein the length (a) of widening is greater than the width (w) of the fine grain sifting nip upwardly of the widening portion (25; 35) of the roll body (21; 31) with respect to the roll axis direction (X). with an adjacent screen roll (10; 20; 30) forms.
• Aspect 6. A screening device according to one of the two immediately preceding aspects, wherein the length (a) of the expansion is at least several centimeters.
• Aspect 7. A screening apparatus according to any one of the preceding aspects, wherein the expansion portion (25; 35) widens in a first subsection (26; 36) in roll axis direction (X), preferably monotone and continuous, and preferably to a largest width, and in one second subsection (27; 37), which adjoins the first subsection (26; 36) in roll axis direction (X), has a greatest width, is preferably at least substantially cylindrical, and wherein the one or more protruding screen structures (22; 32) extends in the roll axis direction (X) to at most the second subsection (27; 37), preferably in the first subsection (26; 36).
• Aspect 8. A screening device according to one of the preceding aspects, wherein the roller body (21; 31) in the expansion section (25; 35), preferably in the second subsection (27; 37) according to one of the two directly preceding aspects, at the outer periphery of a transverse and /or Return conveyor structure (28; 38), preferably a surface structuring or a tooth or rib structure with axially straight teeth or ribs extending at an inclination to the roll axis direction (X), for transversing the transverse surface of oversize particles conveyed into the expansion section (25; Roll axis direction (X) and / or directed against the Walzenachsrichtung (X) conveying action exert.
• Aspect 9. A screening device according to one of the preceding aspects, wherein the roller body (21; 31) in the expansion section (25; 35) widens in a continuously differentiable manner over a length (a) of at least several centimeters.
• Aspect 10. A screening apparatus according to any one of the preceding aspects, wherein the roller body (21; 31) in the expansion section (25; 35) widens conically, trumpet-shaped or bell-shaped over a length (a) of at least several centimeters.
• Aspect 11. A screening device according to one of the preceding aspects, wherein the one or more screen structures (22; 32) in plan view of the roller screen (1) to Walzenachsrichtung (X) have an inclination (α) of greater than 0 ° and less than 90 ° during rotary drive of the screen rollers (20; 30) to convey at least a portion of the oversize fraction in the Walzenachsrichtung (X).
• Aspect 12. A screening device according to one of the preceding aspects, wherein the roll body (21; 31) having the expansion section (25; 35) is axially movable, preferably against the restoring force of an elastic element (15).
• Aspect 13. A screening device according to one of the preceding aspects, wherein an axially elastic element (15) is arranged on at least one of the end faces of the roll body (21; 31) having the widening section (25; 35) and the roll body (21; 31) against the restoring force the elastic element (15) is axially movable.
• Aspect 14. A screening device according to one of the preceding aspects, wherein the screen rollers (20; 30) are rotatably mounted at both axial ends on the frame (2, 3).
• Aspect 15. A screening device according to one of the preceding aspects, wherein a frame wall (3) projects beyond an upper side of the roller screen (1) at a downstream end of the screen rollers (10; 20) in the roll axis direction (X) and at least a part of the roller bodies (11 21) are thinned at the ends facing the frame wall (3) or terminate at an axial distance in front of the frame wall (3), so that the screen rollers (10, 20) adjoin the frame wall (3) facing each have a slender roll section (14), and the clear distance between each adjacent slender roll sections (14) at least twice, preferably at least three times as large as a largest width (w) of the fine grain screen gap between adjacent roll bodies (11; ), so that the slender roller sections (14) form an edge strip (8) which extends transversely to the roller axis direction (X) and adjoins the frame wall (3), in which oversized grain conveyed up to the edge strip (8) passes between the screen rollers (10; 20) can fall through.
• Aspect 16. A screening device according to one of the preceding aspects, wherein the roller body (31) has a further expansion section (35 ') and in the further expansion section (35') either also in or preferably against the Walzenachsrichtung (X) expands.
• Aspect 17. A sifting apparatus according to the preceding aspect, wherein the widening sections (35, 35 ') together form a continuous widening section, in which the roller body (31) widens in the roll axis direction (X) and subsequently tapers again.
• Aspect 18. A screening device according to one of the preceding aspects, wherein the expansion section (25) forms an axial conveying end of the at least one screen roller (20), preferably has a greatest width at the conveying end.
• Aspect 19. A sifting apparatus according to any one of Aspects 1 to 17, wherein the roller body (31) has an upstream roller body portion (31a) and a downstream roller body portion (31b) with respect to the roller axial direction (X), and the widening portion (35) axially between the upward and downward having the downward roller body portion.
• Aspect 20. A screening apparatus according to the preceding aspect, wherein the one or more protruding screen structures (32) of the at least one screen roller (20; 30) having the expansion section (25; 35) in plan view of the roller screen (1) to the roller axial direction (X) Inclination (α) of greater than 0 ° and less than 90 ° and the inclination (α) in the upright roll body portion (31a) up to or in the expansion portion (35) positive and in the downward roll body portion (31b) to maximally to the expansion portion (25; ), preferably up to or into the further expansion section (35 ') of aspect 17, is negative, in order to rotate the screen roller (30) at least a first part of the oversize fraction in roll axis direction (X) and at least a second part of the oversize fraction against the roll axis direction (X) and in the region of the expansion section (35), preferably in the region of the widening sections (35, 35 ') of the aspect 17, transverse to the roller axis direction (X) countries.
• Aspect 21. A screening apparatus according to any one of the preceding aspects, wherein the roller screen (1) comprises a plurality of screen rollers (20; 30) each corresponding to at least one of the preceding aspects.
• Aspect 22. A screening device according to any one of the preceding aspects, wherein in plan view of the roller screen (1) at least every second one of the screen rollers (20; 30) corresponds to at least one of the preceding aspects.
• Aspect 23. A sifting apparatus according to any one of the preceding aspects, wherein in plan view, two or more screen rolls (20; 30) of the wire mesh (1) immediately adjacent to each other correspond to at least one of the foregoing aspects, and the widening portions (25; 35) of adjacent screen rolls (20; 30) are juxtaposed and widen in the same direction, so that the width (w) of the fine grain sieve gap between the adjacent widening portions (25; 35) decreases from both sides, preferably symmetrically.
• Aspect 24. A screening device according to one of the three immediately preceding aspects, wherein the expansion sections (25; 35, 35 ') of the screen rollers (20; 30) are arranged, preferably in the same direction next to each other in the roller axis direction (X), that they are in plan view the roller screen (1) together form a straight strip of expanding sections (25; 35, 35 ') which is oblique or preferably orthogonal to the roller axis direction (X).
• Aspect 25. Screening device for sorting screenings into one or more fine grain fractions and one or more oversize grain fractions, preferably according to one of the preceding aspects, comprising the screening device:
  1. (A) a frame (2, 3) with a frame wall (3) and
  2. (b) a roller screen (1) with screen rollers (20; 30) supported on the frame (2, 3) and supported on the frame (2, 3), each one a roller body (21, 31) and one or more relative to Roller bodies (21, 31) have radially protruding screen structures (22, 32),
  3. (c) such that between the roller bodies (21; 31) of adjacent screen rollers (20; 30) there is in each case a fine grain screen gap through which a fine grain fraction falls, while at least one oversize grain fraction on the roller screen (20) when the screen rollers (20; in Rollachsrichtung (X) on the frame wall (3) to be promoted,
  4. (D) wherein the screen rollers (20; 30) are rotatably mounted at both axial ends on the frame (2, 3) and the frame wall (3), the roller screen (1) at one with respect to the Roll axis direction (X) limited downstream end and on an upper side of the roller screen (1) also protrudes, so that in Walzenachsrichtung (X) no oversize on the frame wall (3) can be promoted,
  5. (e) and wherein at least a part of the roller bodies (21) are thinned at the upstream ends or end at an axial distance in front of the frame wall (3), so that the screen rollers (10; 20) at the ends facing the frame wall (3) each have a slender roll section (14), and the clear distance between each adjacent slender roll sections (14) is at least twice, preferably at least three times as large as a largest width (w) of the fine grain screen gap between adjacent roll bodies (11; 21), so that the slender roller sections (14) form an edge strip (8) extending transversely to the roller axis direction (X) and bordering the frame wall (3), in which oversize grain conveyed up to the edge strip (8) can fall between the screen rollers (10, 20) ,
  A screening device according to aspect 25 may comprise one or more screen rollers, each having a widening section of the type according to the invention, in particular one or more screen rollers each having a widening section which widens only in the roller axis direction, the widening section preferably the axial end of the respective screen roller close to the edge strip forms. The screening device according to aspect 25 is also advantageous as such, without the aspect of widening, because of the demolding, especially in applications where the roller screen is framed by frame walls at both axial ends of the screen rolls.
• Aspect 26. A screening apparatus according to any one of the preceding aspects, wherein the one or more screen structures (22; 32) helically revolve about the axis of rotation (R) of the respective screen roll (10; 20; 30).
• Aspect 27. A screening device according to one of the preceding aspects, wherein the one or more screen structures (22; 32) of adjacent screen rollers (10; 20; 30) are axially offset from each other in plan view of the roller screen (1) and the respective adjacent screen rollers (10; 20; 30) in plan view engage with their protruding screen structures (12; 22; 32).
• Aspect 28. Screening roller for a screening device for sorting screenings into a fine-grain fraction and an oversize-grain fraction, preferably for the screening device according to one of the preceding aspects, the screen-type roller comprising:
  • (a) a roller body (21; 31) having an outer roller body circumference,
  • (b) a bearing journal (23; 33) for rotational mounting of the roller body (21; 31) about an axis of rotation (R)
  • (c) and one or more with the roller body (21; 31) transmitting torque, over the roller body circumference radially projecting sieve structures (22; 32), which is formed by a helically around the roller body circumference spiraling helical structure or a plurality of axially spaced apart screen discs or be .
  • (D) wherein the roll body circumference in an axial Aufweitabschnitt (25; 35) radially widening in Walzenachsrichtung (X).
• Aspect 29. A screen roll according to the preceding aspect, wherein the screen roll (20; 30) can have any feature which in one of the aspects directed to the screen device for the at least one screen roll (20; 30) having the expansion section (25; is described.

Figur 1

eine Siebvorrichtung mit Siebwalzen in einem ersten Ausführungsbeispiel in isometrischer Darstellung,

Figur 2

nebeneinander angeordnete Siebwalzen in einer Draufsicht,

Figur 3

die Siebvorrichtung des ersten Ausführungsbeispiels in einer Draufsicht,

Figur 4

die Siebvorrichtung des ersten Ausführungsbeispiels in einem Schnitt,

Figur 5

eine Siebwalze eines zweiten Ausführungsbeispiels mit einem Aufweitabschnitt an einem axialen Förderende,

Figur 6

einen Aufweitabschnitt mit Quer- und Rückförderstruktur,

Figur 7

eine Siebwalze eines dritten Ausführungsbeispiels mit zwei Aufweitabschnitten als mittleren Walzenabschnitt,

Figur 8

zwei Aufweitabschnitte mit Querförderstruktur für einen mittleren Walzenabschnitt und

Figur 9

mehrere nebeneinander angeordnete Siebwalzen des dritten Ausführungsbeispiels in einer Draufsicht.

Hereinafter, embodiments of the invention will be explained with reference to figures. The features which become apparent in the exemplary embodiments in each case individually and in each combination of features form the above-described embodiments of the invention and in particular the subject-matters of the claims and the subjects of the aspects in each case advantageously. Show it:

FIG. 1

a screening device with screen rollers in a first embodiment in an isometric view,

FIG. 2

juxtaposed screen rollers in a plan view,

FIG. 3

the screening device of the first embodiment in a plan view,

FIG. 4

the screening device of the first embodiment in a section,

FIG. 5

a screen roller of a second embodiment with an expansion section at an axial conveyor end,

FIG. 6

an expansion section with transverse and return conveyor structure,

FIG. 7

a screen roller of a third embodiment with two Aufweitabschnitten as a middle roller section,

FIG. 8

two Aufweitabschnitte with transverse conveying structure for a central roller section and

FIG. 9

a plurality of juxtaposed screen rollers of the third embodiment in a plan view.

FIG. 1 shows a screening device with a roller screen 1 of wire rollers 10 in a first embodiment. To form the roller screen 1, the screen rollers 10 are arranged side by side and rotatable about a respective axis of rotation in a frame of the screening device at both Roll ends stored. The screen rollers 10 are each rotatably supported with a roller end on a frame wall 2 and with the other end of the roll on a frame wall 3 and thereby supported on both sides. The frame walls 2 and 3 protrude beyond an upper side of the roller screen 1 and frame the roller screen 1 at the two roller ends. They form with the roller screen 1 a channel for a sorted by means of the screening device into different fractions Siebgut. The screening device further comprises a drive device for a same-direction rotary drive of the screen rollers 10. From the drive means are in FIG. 1 only clutches 4 for the connection of drive motors and a traction mechanism for coupling the screen rollers 10 for the common rotary drive with the same direction of rotation recognizable. The traction mechanism comprises a plurality of traction means, in the embodiment chains, and rotatably connected to the screen rollers 10 driving wheels 5, in the example gears. The traction devices loop around only the drive wheels of two adjacent screen rollers 10. The drive wheels 5 are correspondingly formed as double drive wheels, so that the driven via the traction elements screen rollers 10 are each driven via one of the double drive wheels and abort over the other of the double drive wheels on the next screen roller 10.

FIG. 2 shows a small section of the roller screen 1 in a plan view on the top thereof. The screen rollers 10 each have a roller body 11 and a screen structure 12, which is formed as a helical structure and rotates about an outer circumferential surface of the roller body 11. Accordingly, the screen structure 12 protrudes radially over the roller body 11 of the respective screen roller 10 in the form of a helix. With rotary drive of the screen rollers 10, these with their screen structures 12 exert a screw action and, consequently, a conveying action in the roller axis direction X.

The roller bodies 11 are in the first embodiment over their entire length each cylindrical, but preferably only by way of example, they are circular cylindrical over their entire length. Between the roller bodies 11 of each adjacent screen rollers 10 remains a fine grain screen gap, which has a constant gap width w over the entire length of the roller body 11. The screen structures 12 of respectively adjacent screen rollers 10 extend axially offset with respect to the roller axis direction X, so that the helix of each one screen roller 10 engages the screen structure of the respective adjacent screen roller 10, ie the screen rollers 10 are formed and arranged with their mesh structures 12 interlocking , With R is in FIG. 2 the axis of rotation of one of the screen rolls 10 arranged in parallel designates.

In the sorting operation, a screenings material, which is placed in a feed area 7 on the top of the roll screen 1, separated into several different grain fractions. A fine grain fraction falls through the sieve gaps downwards, preferably to a below the roller screen 1 arranged Conveying device, such as a belt conveyor, to remove the fine grain fraction from the area of the roller screen 1. The maximum grain size of the fine grain fraction is determined by the gap width w and the axial distances between the intermeshing screen structures 12. The oversize grain not falling through the sieve gap is conveyed by the co-rotating screen rolls 10 on the roller screen 1. The screen rollers 10 exert on the oversize with their screen structures 12 a conveying action in Walzenachsrichtung X and also a conveying effect tangentially to the outer peripheral surface of the roller body 11 in the transverse direction Y from. The oversize is separated into a first oversize fraction and a second oversize fraction. The first oversize fraction contains essentially compact, comparatively heavy parts which, due to their external dimensions, protrude so deeply into the depressions formed between adjacent roll bodies 11 above the respective sieve gap that the sieve structures 12 can act on this oversize grain with their flanks to an extent sufficient to promote the oversize grain in the troughs or over several successive troughs in Walzenachsrichtung X in the edge region formed with the frame wall 3. A second oversize fraction, which in particular contains larger, approximately elongated, and / or lighter parts, is conveyed primarily in the circumferential direction of the screen rollers 10, ie in the transverse direction Y, to an exit area 9 located at the end of the roller screen 1 in the transverse direction Y. , In simple, not least therefore preferred embodiments, the second oversize fraction drops in the discharge area 9 from the roller screen 1 downwards, preferably to a discharge conveyor arranged in the discharge area 9 below the roller screen 1, such as a belt conveyor.

The roller screen 1 forms with the two frame walls 2 and 3, a conveyor channel for the oversize. Problems can arise in particular in the frame wall 3 near the edge region of the roller screen 1, since the screen rollers 10 consistently exert on the oversize grain directed in the Walzenachsrichtung X and thus in the direction of the frame wall 3 conveying effect. In this edge region, the first oversize fraction can accumulate, which can lead to jamming of screen rollers 10 and thus to the interruption of the sorting operation or even damage to the roller screen 1.

In order to counteract the risk of jamming, the screen rollers 10 are diluted in the frame wall 3 near end of roll, so that along the frame wall 3, an edge strip 8 is obtained, in which the gap width w between each adjacent screen rolls 10 is significantly greater than in the remaining region of the roll screen 1. The edge strip 8 can be, as in FIG. 1 shown, advantageously over the entire measured in the transverse direction Y length of the roller screen 1 extend. The measured in Walzenachsrichtung X width of the edge strip 8 may vary over the length of the roller screen 1. Conveniently, however, the edge strip 8 has a constant width. The screen rollers 10 have in their over the width of the edge strip 8 extended, slender roller sections no protruding screen structure, so that the screen rollers 10 in Edge strip 8 in Walzenachsrichtung X exert no conveying effect. The screen rollers may in particular each have a smooth, non-structured outer circumference over the lengths of their slender roller sections. Optionally, individual or each of the screen rollers 10 may have transverse conveyor structures in their thinned roller sections on the outer circumference in order to be able to exert a conveying effect in the transverse direction Y on oversized particles conveyed in the edge strips 8.

FIG. 3 shows a part of the screening device in a plan view of the roller screen 1. Visible is in particular a portion of the edge strip 8, the slender Walzenendabschnitte 14 of the screen rollers 10 form. The slender roller sections 14 are as preferred, but only by way of example each smooth cylindrical, circular cylindrical in the embodiment. The measured in Walzenachsrichtung X length l of the slender roller sections corresponds to the width of the edge strip 8. Between adjacent roller sections 14 each leaves a clear distance d. The distances d are greater than, advantageously at least twice as large as the width w of the sieve gaps for the fine grain. Preferably, the distances d are at least three times and more preferably at least five times as large as the gap width w. The lengths l of the slender roller sections 14 and thus the width of the edge strip 8 are or is greater than, advantageously at least twice as large as the width w of the sieve gaps for the fine grain and preferably at least as great as the distance d. In simple, not least therefore preferred embodiments, the distances d and also the lengths l over the entire edge strips 8 are constant. In principle, however, the distances d and / or the lengths l can vary. In the case of variable distances d, the lengths l are each preferably at least as great as a largest of the distances d. In preferred embodiments, the distances d are as large as structurally possible, ie the slender roller sections 14 are so slim and long in preferred embodiments that the "mesh width" of the roller screen 1 resulting therefrom in the edge strip 8 is so great that all parts of the oversize grain fraction , which get into the edge strip 8 and are not conveyed in the region of the edge strip 8 by the rotational movement of the slender roller sections 14 in the transverse direction Y, between each adjacent roller sections 14 can fall down.

FIG. 4 shows the screening device in a section along the axis of rotation R of the screen rollers 10. The screen rollers 10 each have a central shaft 13 which extends through the frame walls 2 and 3 and rotatably mounted on the frame walls 2 and 3 and thus supported on both sides , The roller body 11 of the screen rollers 10 are sleeve-shaped and rotatably connected in a coaxial arrangement with the shaft 13 of the respective screen roller 10 with the shaft 13. In each of the screen rollers 10, the shaft 13 extends through the roller body 11 and projects beyond both ends of the roller body 11 beyond, whereby the shaft 13 for the roller body 11 of the same screen roller 10 forms a journal at both ends. The helical screen structure 12 is rotatably connected to the associated roller body 11 and runs like a helix on the outer circumference about the roller body 11 to. The frame walls 2 and 3 frame the roller screen 1 left and right, so that no screenings axially over one of the two frame walls 2 and 3, in particular the frame wall 3, also can be promoted.

At the frame wall 3 axially facing ends, the screen rollers 10 each have the described slender roller section 14. As preferred, but only by way of example, the continuous shaft 13 directly forms the slender roller section 14, d. H. the roller section 14 is a section of the shaft 13. The screen rollers 10 dilute from the comparatively large cross-section of the respective roller body 11 in one step on the comparatively slender roller section 14 by the roller body 11 each at a distance l in front of the frame wall 3 ends and the waves thirteenth in each case by this distance l project beyond the axial conveying end of the respective roller body 11 to the facing frame wall 3 and for the purpose of pivotal mounting through the frame wall 3. The screen rollers 10 are seen from the respective roller body 11 out of the frame walls 2 and 3 stored. In the embodiment, the storage takes place directly on the frame walls 2 and 3. In modifications, the shafts 13 or other types of bearing pins of the screen rollers 10, the frame walls 2 and 3 simply protrude and otherwise be rotatably mounted on the frame.

In FIG. 4 are with directional arrows -Z the fall direction of the falling through the roller screen 1 fine grain fraction and registered in the edge strip 8, the direction of fall of up to the edge strip 8 promoted first oversize fraction.

Below the roller screen 1, a dividing wall 6 can expediently be arranged in order to keep away the oversize of the previously separated fine grain in the edge strip 8 between the slender rolling sections 14.

FIG. 5 shows a screen roller 20 of a second embodiment in a radial view. The screen roller 20 comprises a roller body 21 and a screen structure 22 projecting radially over the outer circumference of the roller body 21, which, as in the first embodiment, is helically formed around the roller body 21 in order to convey the first oversize fraction in roller axis direction X. The helical flanks of the screen structure 22 are inclined to the axis of rotation R at an angle α, thus have the inclination angle α corresponding to a slope.

The roller body 21 may, as in the first embodiment, be sleeve-shaped and rotationally immovable with a shaft 23 axially extending through the roller body 21. At a drive end of the screen roller 20, as in the first embodiment, a double drive gear 5 is rotatably connected to the screen roller 20.

Unlike in the first embodiment, the roller body 21 at an end of the roller body an axial Aufweitabschnitt 25, in which the roller body 21 in Walzenachsrichtung X uniformly widens over its entire circumference. The expansion is rotationally symmetric and as preferred, but only by way of example, conical. The expanding portion 25 forms a downstream end portion of the roller body 21 with respect to the roller axis direction X. The roller body 21 is cylindrical from its upstream end to the expanding portion 25, as in the first embodiment.

In a modified roller screen 1, one or more or preferably all of the screen rollers 10 equipped with cylindrical roller bodies 11 in the first exemplary embodiment are each replaced by a screen roller 20. In the roller screen 1 modified in this way, the respective fine-grain sieve gap from the upward end of the roller body 21 to the widening section 25 has the constant gap width w, which decreases in the roll axis direction X in the widening section 25 to a smaller gap width, in the exemplary embodiment gradually, continuously and monotonously. Because of the enlargement of the outer circumference of the roller body 21 in Aufweitabschnitt 25 and concomitantly the reduction of the sieve gap width, the screen roller 20 forms with the or the two adjacent screen rollers on the respective Siebspalt a shallower trough than in the cylindrical roller body portion, wherein the trough the course of expansion gradually flattening out. The engaging in the trough parts of the first oversize fraction are raised in the area of Aufweitabschnitts 25, the oversized grain floats, so to speak. This concomitantly reduces the conveying effect exerted by the screen structure 22 in Walzenachsrichtung X. Furthermore, the conveying action exerted in the circumferential direction Y of the roller body 21 on this oversize grain fraction increases. Each of these effects reduces the risk of jamming in the frame wall 3 (FIG. FIG. 1 ) near the edge region of the modified roller screen 1.

Although the two effects of the floating and the stronger conveying effect in the transverse direction Y over the wire mesh 1, which are advantageous in reducing the risk of jamming, are already achieved, not all, but only a subset of the screening rolls 10 of the first embodiment are replaced by screen rolls 20, For example, every second screen roller 10, and a positive effect is basically already achieved by replacing only a single screen roller 10, it corresponds to preferred embodiments, if in the modified roller screen 1 a plurality of screen rollers 20 are arranged directly adjacent to each other or, more preferably, the modified roller screen 1 exclusively or at least predominantly of screen rollers 20 is formed.

The modified roller screen 1, which has one or more screen rollers 20 instead of one of the screen rollers 10, may also have the edge strip 8 of the first embodiment in embodiments in which all or the majority of the screen rollers 10 are replaced by screen rollers 20 as preferred. As a result, jamming by oversized grain conveyed in the roller axis direction X can be counteracted even more reliably, in particular in embodiments in which the modified roller screen 1 also has one or more of the screen rollers 10. However, this is not necessary, since the second oversize fraction floats in the region of the widening 25, in the widening section 25 the conveying effect in the roll axis direction X decreases and the conveying effect in the transverse direction Y increases. The roller body 21 can accordingly extend directly to the frame wall 3. In the modified roller screen 1, an edge strip of juxtaposed Aufweitabschnitten 25 apart from slender rolling sections 14 (FIG. Figures 3 and 4 ) replace free edge strip 8 of the first embodiment.

The roller body 21 can expand in the expansion section 25 from a smallest radial width, preferably a smallest circle diameter, to a maximum radial width, preferably a largest circle diameter, and ends immediately upon reaching the greatest width. However, more preferably, the expansion portion 25, as in FIG. 5 recognizable, a first subsection 26 and in Walzenachsrichtung X to the lower portion 26 immediately thereafter a second subsection 27. In the exemplary embodiment, the two subsections 26 and 27 already form the entire widening section 25. In the subsection 26, the widening from the smallest radial width to the largest radial width of the widening section 25 and also of the roller body 21 takes place altogether. The subsection 27 is cylindrical, preferably circular cylindrical. The subsection 26 has an axial length a, and the subsection 27 has an axial length b. If the widening section 25 is composed of the two subsections 26 and 27, the total length of the widening section 25 thus corresponds to the sum of the lengths a and b. The subsection 26 is preferably longer than the subsection 27 to distribute the expansion over a correspondingly large length a and to avoid an abrupt transition. The length a is preferably at least 1.5 times greater, more preferably at least two times greater than the length b. Since the cylindrical or at least substantially cylindrical sub-section 27 serves the purpose of exerting a conveying action in the transverse direction Y on the oversize grain fraction conveyed into the sub-section 27, namely due to peripheral contact, the sub-section 27 should, on the other hand, have a length b sufficient for this purpose. It is advantageous if the length b is at least one tenth of the length of the expansion section 25 or one eighth of the length a. Preferably, the length b is at least one eighth of the length of the expansion section 25 and / or at least a sixth of the length a.

In order to reduce the conveying effect in the roll axis direction X in the area of the widening section 25, the wire structure 22 may end before or at the widening section 25. However, more preferably, the screen structure 22 extends into the expansion section 25, in the second embodiment into the subsection 26, and terminates a short distance from the downstream end of the expansion section 25. Preferably, the screen structure 22 extends only to a maximum of the subsection 27, which is advantageously free of in Rollachsrichtung promotional structures.

The screen structure 22 may be flattened in the expansion section 25. An imaginary virtual envelope H applied to the outer periphery of the screen structure 22 is shown in FIG FIG. 5 shown in dashed line. The envelope H, which may be cylindrical in particular over the entire axial length of the roller body 21 up to or preferably up to the expansion section 25, tapers in the expansion section 25 because of the flattening of the screen structure 22, preferably evenly over the entire circumference of the roller body 21.

FIG. 6 shows a modified expansion section 25, the in FIG. 5 can replace replacing section 25 shown. The modified expansion section 25 has in its roll body end forming subsection 27 on the outer periphery of a transverse conveying structure 28 in order to reinforce the conveying effect in the transverse direction Y yet. The transverse conveying structure 28 can be formed as a flat surface structure, for example as knurling or corrugation, which extends radially behind the screen structure 22 of at least the cylindrical roller body section, in comparison to the screen structure 22, or as peripherally extending external toothing or ribbing. The outer toothing or ribbing can be used as straight teeth or ribs with axial ribs or in further developments, as in FIG. 6 be formed as helical teeth or with differently with respect to the rotation axis R or Walzenachsrichtung X inclined teeth or ribs formed. In the roll axis direction X with inclined teeth or ribs, the screen roller 20 in the subsection 27 also exerts a conveying action against the Walzenachsrichtung X and thereby keeps the oversize away from the frame wall 3 safer or reduces one of the oversize possibly on the frame wall 3 in Walzenachsrichtung X exerted Print.

As far as the screen roller 20 no differences to the screen roller 10 of the first embodiment described or from the FIGS. 5 and 6 can be seen, the screen roller 20 of the second embodiment of the screen roller 10 of the first embodiment correspond, so that reference is made to the comments on the first embodiment in addition.

FIG. 7 shows a screen roller 30 of a third embodiment in a radial view. The screen roller 30 has a roller body 31 in the roller axis direction X progressively an upwardly rotating roller body portion 31 a, a widening portion 35, a further expansion section 35 'and a downward roller body portion 31b. The widening section 35 immediately adjoins the roller body section 31a, the further widening section 35 'directly adjoins the widening section 35 and the roller body section 31b directly adjoins the further widening section 35'. The roller body sections 31a and 31b are axially outer roller body sections and form the two ends of the roller body 31. The roller body sections 31a and 31b can have, in particular, a cylindrical outer circumference over their entire length. A shaft 33 extends through the roller body 31 and serves as in the other embodiments as a bearing pin for a two-sided storage of the screen roller 30. The shaft 33 protrudes on both sides beyond the roller body 31, as in the other embodiments on both sides of the screen roller 30 respectively to form a pivot bearing with the frame, for example, the frame walls 2 and 3. In principle, however, the roller body 31 can also have differently shaped roll necks for pivotal mounting.

The helical screen structure 32, which is also in the third exemplary embodiment, comprises a first screen structure section 32a, which extends helically in the first roller body section 31a, preferably over its entire axial length, and a second screen structure section 32b, which extends helically in the second roller body section 31b, preferably over the entire thereof axial length. An inclination angle α and thus a pitch of the helical screen structure 32 is selected such that the upward screen structure section 32a exerts a conveying action in the roller axis direction X on the oversize grain. The helix of the downstream screen structure section 32b has a course opposite to the screen structure section 32a. The inclination angle α or the pitch of the screen structure section 32b may be as great as the inclination angle α of the screen structure section 32a, but have a negative sign. The angles of inclination of the two sections 32a and 32b may, however, in principle also differ in magnitude and not only in sign. Due to the counter-rotating screen structure sections 32a and 32b, the screen roller 30 exerts a conveying action in the roller axis direction X on the oversize grain in the roller body section 31a and on the oversize in the roller body section 31b a conveying action against the roller axis direction X, d. H. in the -X direction.

Axially between the roller body sections 31a and 31b, the widening sections 35 and 35 'form a continuous widening section 35, 35'. In Aufweitabschnitt 35, the roller body 31 widens in Walzenachsrichtung X from the radial width of the roller body portion 31 a to a maximum radial width. In the further expansion section 35 ', the roller body 31 also widens, with respect to the roller axis direction X, from the radial width of the roller body section 31b to a maximum radial width. The largest radial width of Aufweitabschnitts 35 and the largest radial width of the further expansion section 35 'are the same, as preferred, but in principle may also be different.

The cylindrical roller body portions 31a and 31b have the same radial width, but basically, the radial widths of the roller body portions 31a and 31b may be different from each other. In the exemplary embodiment, the roller body sections 31a and 31b have the same length and / or the widening sections 35 and 35 'have the same length. In principle, however, the roller body sections 31a and 31b may differ in length from one another and / or the widening sections 35 and 35 'may differ in length from one another. However, in the third embodiment, the unitary screen roller body 31 is symmetrical with respect to a plane of symmetry extending between the expanding sections 35 and 35 'normal to the rotation axis R. Because of the reverse nature of the screen structures 32a and 32b, the screen structure 32 composed of the two screen structures 32a and 32b is also symmetrical about the same plane of symmetry.

As such, the expansion section 35 corresponds to the expansion section 25 of the second embodiment. The further expansion section 35 'also corresponds to the expansion section 25 of the second embodiment, apart from the widening taking place against the roller axis direction X. Both Aufweitabschnitte 35 and 35 'have in their axially facing end portions in which they abut directly against each other, a cylindrical portion. As in the second embodiment, the expansion portion 35 has a widening first sub-portion 36a and then the cylindrical sub-portion 37 thereafter. In mirror image, this also applies to the further expansion section 35 ', which widens in a first subsection 36b from the width of the roller body portion 31b to the largest radial width and cylindrical with the largest radial width in the second subsection 37 common with the widening section 35.

For the screen roller 30, an imaginary virtual envelope H applied to the above screen structure 32 is again drawn. The envelope H is cylindrical in the roll body portion 31a, constricts in the region of the expansion portion 35 except for the lower portion 37, then widens mirror-symmetrically in the further expansion portion 35 'to the width of the screen structure portion 32b and is again cylindrical over the length of the roll body portion 31b ,

In order to relieve the above screen structure 32 when jammed in Walzenachsrichtung X, the screen structure 32 may be arranged axially movable to a small extent. As preferred, but only by way of example, the axial mobility of the screen structure 32 is achieved by an axially movable arrangement of the roller body 31. The roller body 31 is axially floating on the shaft 33 arranged. The axially floating arrangement is realized by means of elastic elements 15, one of which is arranged at the left front end and one at the right front end of the roller body 31. The elastic elements 15 may in particular be elastomeric elements or natural rubber elements. Appropriately, they are the sleeve shape of the roller body 31 in accordance with annular. They allow due to their elasticity in and against the Walzenachsrichtung X elastic yielding of the roller body 31 and the immovably connected screen structure 32 in the millimeter range, for example, a yielding by a maximum of 1 to 3 mm. The elastic elements 15 force the deflected roller body 31 by means of elastic restoring force always again in the direction of an unloaded state corresponding axial position.

The roller screen 1 of the first embodiment can be modified by replacing one, several or preferably all screen rollers 10 by a respective screen roller 30. In that regard, the statements made for the second embodiment apply. In the sorting operation with the modified roller screen 1, in the region of each screen roller 30 in the roller body section 31a, oversize in the roller axis direction X is fed to the widening section 35 and in the roller body section 31b against the roller axial direction, in direction -X, oversize to the further widening section 35 '. In the contiguous expansion section 35, 35 ', the oversize undergoes an increased conveying effect in the transverse direction Y. The risk of jamming in an edge region near a frame wall, such as the frame wall 3, is counteracted particularly effectively.

Another advantage of the screen rollers 20 and 30 and in particular the screen roller 30 is that on a not usable for sorting edge strip 8 (FIG. FIG. 1, 3 and 4 ) can be omitted. A screening device with screen rollers 20 and / or screen rollers 30 can be shorter with the same screen quality in Walzenachsrichtung X. Alternatively, the selectivity of the roller screen 1 can be improved with the same width of the screening device and / or the throughput can be increased, since the effective area of the roller screen 1 can be increased at a constant total length in the transverse direction Y. Furthermore, no excess grain must be removed under the roller screen.

FIG. 8 shows from the screen roller 30 only the contiguous expansion section 35, 35 '. The axial lengths a of the subsections 36a and 36b are the same, but in principle may differ from one another. The subsection 37 connects the subsections 36a and 36b and has the length b. He is as preferred, but only as an example circular cylindrical. The roller body 31 can be smooth everywhere in the expansion section 35, 35 'outside. It can also have a transverse conveying structure in the expansion section 35, 35 '. The transverse conveying structure, if present, can be provided in particular in the subsection 37 and preferably only in the subsection 37. Thus, the roller body 31 in the expansion portion 35, 35 'on an outer peripheral surface, as in FIG. 8 have a transverse conveying structure 38 in the form of a surface structuring, such as a knurling or ribbing, or a more pronounced shaped external toothing or ribbing in order to enhance the cross-conveying effect. In sub-section 37 can also be formed a transverse and Rückförderstruktur. With regard to an optional transverse and / or return structure and the expansion sections 35 and 35 ', reference is made to the comments on the second embodiment, ie to the screen roller 20. As far as differences to the screen rollers 10 of the first embodiment and / or the screen roller 20 of the second embodiment is not described or from the FIGS. 7 and 8 can not be seen, the screen roller 30 of the third embodiment may be formed as one of the screen rollers 10 of the first embodiment and / or the screen roller 20 of the second embodiment, so that reference is made to the respective embodiments.

FIG. 9 shows in a plan view a section of a modified roller screen, which is formed from screen rollers 30 of the third embodiment or at least one screen area with a plurality of juxtaposed screen rollers 30 has. The screen rollers 30 each have, as already explained, in an axially central roller section the contiguous expansion section 35, 35 ', so that from a right outer roller screen strip and a left outer screen strip oversize in the direction X and -X to each associated expansion section 35 and 35 'is promoted. In the contiguous expansion section 35, 35 ', due to the widening taking place on both sides of the respective screen roller 30, the gap width w of the fine-grain screen gaps formed between adjacent screen rollers 30 decreases. The oversized grain in question floats in the contiguous expansion section 35, 35 'and increasingly experiences a conveying effect in the transverse conveying direction Y when floating. For the sake of completeness, it should be noted that in many applications Siebgutchargen have an oversize grain fraction which is essentially also left and right of the home contiguous Aufweitabschnitt 35, 35 'is conveyed substantially only in the transverse conveying direction Y, so no practically significant fall promotion in or against the Walzenachsrichtung X experiences. This oversize fraction is conveyed substantially only in the roller screen strips on the left and right of the contiguous expansion section 35, 35 'in the circumferential direction or transverse conveying direction Y, while the oversized grain fraction, which is significantly conveyed axially, in the middle roller screen strip of the successive in the transverse direction Y, preferably immediately successive, Aufweitabschnitten 35, 35 'is conveyed in the transverse direction Y.

Reference numerals:

1

Roller screen

2

frame wall

3

frame wall

4

clutch

5

drive wheel

6

partition wall

7

remit

8th

edge strips

9

output area

10

dandy roll

11

roller body

12

protruding screen structure

13

wave

14

slender roller section

15

elastic element

16

-

17

-

18

-

19

-

20

dandy roll

21

roller body

22

protruding screen structure

23

wave

24

-

25

expanding section

26

subsection

27

subsection

28

Cross conveyor structure, transverse and return conveyor structure

29

-

30

dandy roll

31

roller body

31a

Roll body section

31b

Roll body section

32

protruding screen structure

32a

Siebstrukturabschnitt

32b

Siebstrukturabschnitt

33

wave

34

-

35

expanding section

35 '

expanding section

36a

subsection

36b

subsection

37

subsection

38

Transverse and / or return structure

R

axis of rotation

X

roll axes

Y

transversely

Z

vertical direction

a

Length first subsection

b

Length second subsection

d

distance

l

Width of the marginal strip

w

gap width

α

tilt angle

Claims (17)

Sieve device for sorting screenings into one or more fine grain fractions and one or more oversize grain fractions, the screening device comprising: (a) a frame (2, 3) and (b) a roller screen (1) with screen rolls (20, 30) supported on the frame (2, 3) and supported on the frame (2, 3) side by side so as to be rotatable about each roll axis (R), preferably rotatably mounted at both axial ends on the frame (2, 3), each having a roller body (21, 31) and one or more screen structures (22, 32) projecting radially relative to the roller body (21, 31), (c) wherein between the roller bodies (21; 31) of adjacent screen rollers (20; 30) there is in each case a fine grain screen gap through which a fine grain fraction falls, while during rotary drive of the screen rollers (20; 30) an oversize fraction on the roller screen (1) in the roller axial direction (X) is promoted,
characterized in that (d) the roll body (21; 31) of at least one of the screen rolls (20; 30) radially expands in an axial expansion section (25; 35) in the roll axis direction (X) (e) and the width (w) of the fine grain screen gap formed by the widening roller body (21; 31) with the roller body (21; 31) of an adjacent screen roller (20; 30) along the widening portion (25; 35) in the roller axial direction (X) decreases. A screening apparatus according to the preceding claim, wherein a virtual wrap (H) is applied to the outer circumference of the one or more screen structures (22; 32) of the at least one screen roll (20; 30) having the widening portion (25; along the Aufweitabschnitts (25; 35) in Walzenachsrichtung (X) tapers. Screening apparatus according to one of the preceding claims, wherein the screen roller (20; 30) also has one or more screen structures (22; 32) radially projecting over the roller body (21; 31) in the expansion section (25; Screening apparatus according to one of the preceding claims, wherein the expansion section (25; 35) in a first subsection (26; 36) widens gradually, preferably monotonically and continuously, to a maximum width in the roll axis direction (X) and in a second subsection (27 37) adjoining the first subsection (26; 36) in roll axis direction (X) is at least substantially cylindrical, preferably with the largest width. A screening apparatus according to any one of the preceding claims, wherein the expansion portion (25; 35) widens in a first subsection (26; 36) in the roll axis direction (X), preferably monotone and continuous and preferably to a maximum width, and in a second subsection (Fig. 27; 37), which adjoins the first subsection (26; 37) in roll axis direction (X), has a largest width, is preferably at least substantially cylindrical, and wherein the one or more protruding screen structures (22; Roller axial direction (X) to at most the second subsection (27; 37), preferably in the first subsection (26; 36), extend or extend. Screening device according to one of the preceding claims, wherein the roller body (21; 31) in the expansion section (25; 35), preferably in the second subsection (27; 37) according to one of the two directly preceding claims, at the outer periphery of a transverse and / or Rückförderstruktur (28, 38), preferably a tooth or rib structure with axially straight teeth or ribs extending at an inclination to the roller axis direction (X), in order to have an oversize transverse to the roller axis direction (X) on oversized grain conveyed into the expansion section (25; and / or to exert against the Walzenachsrichtung (X) directed conveying effect. Screening device according to one of the preceding claims and at least one of the following features: (i) the roll body (21; 31) expands continuously in the expansion section (25; 35) over a length (a) of at least several centimeters; (ii) the roll body (21; 31) widens conically, trumpet-shaped or bell-shaped in the expansion section (25; 35) over a length (a) of at least several centimeters. Screening device according to one of the preceding claims, wherein the one or more screen structures (22; 32) in plan view of the roller screen (1) to Walzenachsrichtung (X) have an inclination (α) of greater than 0 ° and less than 90 ° to the case of rotary drive of Screening rollers (20; 30) to promote at least a portion of the oversize grain fraction in the Walzenachsrichtung (X). Screening device according to one of the preceding claims and at least one of the following features: (i) the roll body (21; 31) having the expansion section (25; 35) is axially movable, preferably against the restoring force of an elastic element (15); (ii) an axially elastic element (15) is arranged on at least one of the end faces of the roll body (21, 31) having the widening section (25; Roller body (21; 31) is axially movable against the restoring force of the elastic element (15). A screening device according to one of the preceding claims, wherein a frame wall (3) projects beyond an upper side of the roller screen (1) at a downstream end of the screen rollers (10; 20) in the roll axis direction (X) and at least a part of the roller bodies (11; at the ends of the frame wall (3) facing ends or at an axial distance in front of the frame wall (3), so that the screen rollers (10; 20) at the frame wall (3) facing ends each have a slender roll section (14) , and the clear distance between respectively adjacent slender roller sections (14) is at least twice, preferably at least three times as large as a maximum width (w) of the fine-grain screen gap between adjacent roller bodies (11; 21) such that the slender roller sections (14) are transversely form to the Walzenachsrichtung (X) and bordering the frame wall (3) edge strips (8) form, in which up to the edge strip (8) promoted oversize between the S rolling (10; 20) can fall through. Screening device according to one of the preceding claims, wherein the roller body (31) has a further widening section (35 ') and widens in the further widening section (35') either likewise in or preferably against the roller axial direction (X), wherein in preferred embodiments the widening sections (35) 35, 35 ') together form a continuous expansion section, in which the roller body (31) widens in the roller axial direction (X) and subsequently tapers again. Screening device according to one of the preceding claims and exactly one of the following two features: (i) the expanding portion (25) forms an axial conveying end of the at least one screen roll (20) and preferably has a largest width at the conveying end; (ii) the roll body (31) has an upstream roll body portion (31a) and a downstream roll body portion (31b) with respect to the roll axis direction (X), and the expansion portion (35) axially between the upstream and downstream roll body portions. A screening device according to the preceding claim, wherein the one or more projecting screen structures (32) of the at least one screen roller (20; 30) having the widening section (25; 35) have an inclination (α) in plan view of the roller screen (1) to the roller axial direction (X) ) of greater than 0 ° and less than 90 °, and the inclination (α) in the upstream roll body section (31a) up to or into the expansion section (35) is positive and in the downward roller body section (31b) to at most the expansion section (25; 35), preferably to or into the further expansion section (35 ') of claim 15, negative, to at least a first part of the oversize grain fraction in rotational drive of the screen roller (30) Roll axial direction (X) and at least a second part of the oversize fraction against the Walzenachsrichtung (X) to promote and in the region of the Aufweitabschnitts (35), preferably in the region of the Aufweitabschnitte (35; 35 ') of claim 15, transverse to the Walzenachsrichtung (X) abzufördern , Screening device according to one of the preceding claims, wherein in plan view of the roller screen (1) at least every second of the screen rollers (20; 30) respectively corresponds to at least one of the preceding claims. Screening device according to one of the preceding claims, wherein in plan view two or more screen rolls (20; 30) of the roller screen (1) arranged next to each other correspond to at least one of the preceding claims and the expansion sections (25; 35) of adjacent screen rollers (20; 30) side by side are arranged and expand in the same direction, so that the width (w) of the Feinkornsiebspalts between the adjacent Aufweitabschnitten (25; 35) is reduced from both sides, preferably symmetrically. Screening device according to one of the three immediately preceding claims, wherein the widening sections (25; 35, 35 ') of the screen rollers (20; 30) are arranged, preferably in the same direction next to each other in the roller axis direction (X), that they are in plan view of the roller screen (10). 1) together form a straight, to Walzenachsrichtung (X) oblique or preferably orthogonal strip of Aufweitabschnitten (25, 35, 35 '). Screening roller for a screening device for sorting screenings into a fine-grain fraction and an oversize-grain fraction, preferably for the screening device according to one of the preceding claims, comprising the screen-type roller (a) a roller body (21; 31) having an outer roller body circumference, (b) a bearing journal (23; 33) for rotational mounting of the roller body (21; 31) about an axis of rotation (R) (c) and one or more with the roller body (21; 31) transmitting torque, over the roller body circumference radially projecting sieve structures (22; 32), which is formed by a helically around the roller body circumference spiraling helical structure or a plurality of axially spaced apart screen discs or be . (d) wherein the roll body circumference radially expands in an axial expansion section (25; 25) in the roll axis direction (X), (e) and wherein the screen roll (20; 30) may have any feature described in any of the claims directed to the screen device for the at least one screen roll (20; 30) having the widening portion (25;

Images