EP3452233B1 - Circular screen and device for producing same - Google Patents

Description

The present invention relates to a cylinder mold and a production device for a cylinder mold.

From the DE 20 2006 011 089 U1 a sieve with a plurality of sieve openings in a sieve surface is known. The sieve has a plurality of sheet metal strip layers placed on edge, arranged next to one another and in some areas in contact with one another. The sheet metal strip layers are arranged in such a way that lateral end faces of the sheet metal strip layers are arranged essentially in the plane of the screen surface and areas of adjacent sheet metal strip layers that are not in contact define screen openings. Such a sieve has the disadvantage that its sieve openings often clog during operation.

It is therefore an object of the present invention to provide a cylinder mold which is inexpensive to manufacture and in which fewer blockages of the sieve openings occur during operation.

This object is achieved by the subject matter of the independent claims; advantageous developments emerge from the dependent claims.

A cylinder mold according to the invention comprises an essentially cylindrical and / or essentially frustoconical base body which is formed from a metal strip wound into a plurality of sheet metal strip turns; wherein the sheet metal strip describes a wavy line oscillating about a reference plane with wave crests and with wave troughs; Adjacent sheet metal strip windings in each case bear against one another in such a way that sieve openings are formed in the radial direction; and wherein the height of the wave crests and the wave troughs of the sheet metal strip windings, based on the reference plane, increases in the radial direction outward, so that the size of the sieve openings increases in the flow direction radially outward; or wherein the height of the wave crests and the wave troughs of the sheet metal strip windings, based on the reference plane, increases in the radial direction inwards, so that the size of the screen openings increases radially inwards in the flow direction.

Such a cylinder mold can be produced inexpensively. The essentially cylindrical or essentially frustoconical base body of the cylinder mold is formed from a sheet metal strip which is wound into a multiplicity of sheet metal strip windings and which describes an oscillating undulating line with wave crests and with wave troughs.

The respective adjacent sheet metal strip windings are in contact with one another in some areas and each form sieve openings in the radial direction between the contact areas. The screen openings have in particular a repeating or constant opening profile.

The sheet metal strips can be wound up in a helical manner in the axial direction, one above the other, resulting in an essentially cylindrical basic shape of the base body of the cylinder mold.

As an alternative to this, it is possible for the sheet metal strip to be wound up in a helical manner, that is to say with a diameter that changes in the axial direction, which essentially results in a truncated cone-like basic shape of the cylinder sieve base body.

It is also possible for a cylinder mold according to the invention to form a combination of essentially frustoconical and / or essentially cylindrical base body sections.

According to one of the knowledge underlying the invention, the inventors of the present application have found that the clogging of conventional round sieves, such as those from the DE 20 2006 011 089 U1 are known, can be attributed to the fact that sieve openings with a constant flow cross section in the radial direction have a strong tendency to clog.

According to a basic idea of the present invention, the height of the wave crests and the wave troughs of the sheet metal strip windings increases or decreases in the radial direction relative to the reference plane, so that the size of the sieve openings increases or decreases in the radial flow direction outward.

The reference plane lies in particular in a spiral shape and follows the winding direction of the sheet metal strip.

The sieve openings thus form a small inlet opening in the flow direction and a cross section that widens at least in some areas towards the outlet opening. On the one hand, this reduces the tendency to clog, and on the other hand, such sieve openings can simply be flushed free even if they are blocked during operation, for example in an intermittent flushing operation with a corresponding flushing medium such as water.

The sheet metal strip is in particular shaped to be periodically repeating. The wave line with wave crests and wave troughs is therefore essentially the same for the sheet metal strip windings lying one above the other.

A cylinder sieve according to the invention can also be referred to as a sieve basket and is used particularly in the paper and pulp industry, in wastewater treatment, in fiber recovery, in sludge thickening, in chemical production plants, in juice presses, in the food industry or generally in sorting and filtration processes.

According to a first embodiment of the invention, the cylinder mold is a cylinder mold with a flow direction from the inside to the outside; and the height of the wave crests and the wave troughs of the sheet metal strip windings, based on the reference plane, and thus the amplitude increases in the radial direction outwards, so that the size of the sieve openings increases in the flow direction from the inside, radially outwards

Such a round sieve has very good sieving results when a medium to be sieved flows through from the inside to the outside, and clogging of the sieve openings is largely avoided.

According to a further embodiment of the invention, the cylinder mold is a cylinder mold with a flow direction from the outside to the inside; and the height of the wave crests and the wave troughs of the sheet metal strip windings, based on the Reference plane, in the radial direction and thus the amplitude increases inward, so that the size of the sieve openings increases in the flow direction from the outside radially inward.

Such a round sieve has very good sieving results when a medium to be sieved flows through it from the outside in, and clogging of the sieve openings is largely avoided.

According to a further embodiment of the invention, the oscillating wavy line has wave peaks and wave peaks flattened with wave troughs and flattened wave troughs.

In the case of a wavy line with flattened wave crests and with flattened wave troughs, screen openings of greater width, but smaller height, typically result than in the case of an essentially sinusoidal wavy line.

According to a further embodiment, the oscillating wave line with wave crests and with wave troughs essentially has a sinusoidal shape with round or rounded wave crests and with round or rounded wave troughs.

In the case of a wavy line with round or rounded wave crests and with round or rounded wave troughs, screen openings of greater height but smaller width typically result than with a flattened wavy line.

According to a further embodiment, adjacent sheet metal strip windings are in contact with one another with their flank sections between the wave crests and the wave troughs in such a way that sieve openings are formed in the radial direction between the wave crests and the wave troughs of sheet metal strip windings lying one above the other.

In other words, in this embodiment the sheet metal strip turns are arranged in phase one above the other, so that the wave troughs of a sheet metal strip turn each lie above the corresponding wave troughs of the sheet metal strip turn below and that the wave peaks of a sheet metal strip turn each over the wave peaks of the respective sheet metal strip winding arranged underneath lie, each seen in the axial direction. The flank sections between the wave crests and the wave troughs of adjacent sheet metal strip windings lie against one another.

The screen openings formed in this way have, with an essentially sinusoidal design of the wavy line of the sheet metal strip, essentially a crescent-like basic shape and, with a flattened, wavy design of the corrugated line of the sheet metal strip, a roughly trapezoidal basic shape, each looking radially inward or radially outward.

Alternatively, the sheet metal strip turns can also be arranged offset to one another, so that the corrugation troughs of an upper sheet metal strip turn abut the corrugation peaks of the sheet metal strip turn below and the screen openings through the free cross section between a corrugation peak of an upper sheet metal strip turn and a are formed in the axial direction underlying wave trough of a lower sheet metal strip turn.

It is also possible for sheet metal strip windings to be arranged one on top of the other in intermediate positions between the two mentioned arrangement options.

It is also possible for the areas of adjacent sheet metal strip turns that are in contact with one another to vary over the course of the turns of the sheet metal strip.

According to a further embodiment, the circumferential surface formed by the sieve openings, in particular by the smallest openings of the sieve openings in each case, is 15-50% of the sieve opening area of the cylinder mold.

Thus, the ratio of the sieve opening area of the cylinder to the sieve opening area or total jacket area can be adjusted for the respective application by appropriately designing the corrugated shape of the sheet metal strips and by appropriately selecting the contact areas of adjacent sheet metal strip turns.

Larger screen opening area ratios based on the screen opening area can be achieved than is possible with round screens made from a bent and stamped sheet metal.

In particular if the wave crests and the wave troughs have a flattened shape, a large screen opening area ratio can be achieved, which is in a range of 30-50%.

According to a further embodiment, adjacent sheet-metal strip windings are in contact with one another, and the round screen furthermore has a frame which holds the respectively adjacent sheet-metal strip windings in the abutting position against one another.

In this embodiment, adjacent sheet metal strip windings do not have to be connected to one another by welding connections. The holding of the adjacent sheet metal strip turns in relation to one another and the sieve openings is brought about by a frame which fixes the sheet metal strip turns to one another in the axial direction.

As an alternative or in addition to this, each adjacent sheet metal strip windings can be welded to one another. In this embodiment, a separate frame is unnecessary, but can still be provided.

According to a further embodiment, each adjacent sheet-metal strip turns are welded to one another on at least some of the flank sections of adjacent sheet-metal strip turns that are in contact with one another. This represents a particularly durable and robust embodiment of the cylinder mold.

According to a further embodiment, the angle of inclination of the wave crests and the wave troughs of the sheet metal strip windings, based on the reference plane, is 1-20 ° in the radial direction.

According to a further embodiment, the sheet metal strip has an essentially rectangular cross section.

Typical dimensions of the sheet metal strip are as follows: width 2-5mm, height 3-5mm, stretched length, based on a period, 2-5mm.

Typical sieve openings have an opening width of 0.1-0.3mm and / or a height of 1-3mm.

• eine Zuführeinheit für einen Blechstreifen;
• wenigstens ein Paar von gegenläufigen Zahnrädern, die so ober- und unterhalb des durchzulaufenden Blechstreifens angeordnet und ausgebildet sind, dass der Blechstreifen beim Durchlaufen dadurch in eine Wellenform mit Wellenbergen und Wellentälern umgeformt wird; und
• wenigstens zwei Rundungswalzen, die so neben dem durchlaufenden Blechstreifen angeordnet und ausgebildet sind,
• dass der Blechstreifen zu einer Vielzahl von Blechstreifen-Windungen aufgewickelt wird, die eine um eine Bezugsebene oszillierende Wellenlinie mit Wellenbergen und mit Wellentälern beschreiben; und
• dass benachbarte Blechstreifen-Windungen so aneinander anliegen, dass in Radialrichtung Sieböffnungen gebildet sind;

wobei das wenigstens eine Paar von gegenläufigen Zahnrädern eine Zahnradgeometrie aufweist, die den Querschnitt des Blechstreifens so verändert, dass, nach dem Durchlauf des Blechstreifens durch die wenigstens zwei Rundungswalzen, die Höhe der Wellenberge und der Wellentäler der Blechstreifen-Windungen, bezogen auf die Bezugsebene, in Radialrichtung nach außen zunimmt, sodass die Größe der Sieböffnungen in Durchströmungsrichtung radial nach außen zunimmt; oder die Höhe der Wellenberge und der Wellentäler der Blechstreifen-Windungen, bezogen auf die Bezugsebene, in Radialrichtung nach innen zunimmt, sodass die Größe der Sieböffnungen in Durchströmungsrichtung radial nach innen zunimmt.The invention also relates to a manufacturing device for a cylinder mold of the type described above, which has the following features:

• a feed unit for a sheet metal strip;
• at least one pair of counter-rotating gears which are arranged and designed above and below the sheet metal strip to be passed through, that the sheet metal strip is thereby transformed into a wave shape with wave crests and wave troughs as it passes through; and
• at least two rounding rollers, which are arranged and designed next to the continuous sheet metal strip,
• that the sheet metal strip is wound up to form a multiplicity of sheet metal strip windings which describe a wavy line oscillating about a reference plane with wave crests and with wave troughs; and
• that adjacent sheet metal strip windings bear against one another in such a way that sieve openings are formed in the radial direction;

wherein the at least one pair of counter-rotating gears has a gear geometry that changes the cross section of the sheet metal strip so that, after the sheet metal strip has passed through the at least two rounding rollers, the height of the wave crests and the wave troughs of the sheet metal strip windings, based on the reference plane, increases in the radial direction outward, so that the size of the screen openings increases in the flow direction radially outward; or the height of the wave crests and the wave troughs of the sheet metal strip windings, based on the reference plane, increases in the radial direction inwards, so that the size of the sieve openings increases radially inwards in the flow direction.

With such a production device, a cylinder mold according to the invention can be produced inexpensively.

The advantages and embodiments given above with reference to the cylinder mold apply in the same way to the manufacturing device according to the invention and are not explained again here to avoid repetition.

The sheet metal strip can either already be supplied in the desired length, alternatively an endless sheet metal strip can be supplied and after production of the cylinder mold with the desired number of sheet metal strip turns.

According to a further finding on which the invention is based, the inventors have determined that in a rounding process in which a sheet metal strip with a wave shape with wave crests and troughs is wound up to form a plurality of sheet metal strip windings, some of which lie against one another and form sieve openings in between, so that overall a cylinder mold with a substantially cylindrical and / or substantially frustoconical base body is formed, the effects of stretching the waveform on the outside and compressing the waveform on the inside occur, so that the height of the wave crests and the wave troughs and thus the amplitude and the Size of the sieve openings increases radially from the outside inwards.

In other words, during the rounding process, the amplitude on the inside of the undulating sheet metal strip is higher because - to put it simply - the material has to evade.

According to a further basic concept of the present invention, the curvature of the wave-shaped sheet metal strip over its width can be specifically influenced in advance by a corresponding gear geometry of the at least one pair of counter-rotating gears after the rounding process.

A cylinder sieve in which the size of the sieve openings increases radially from the outside to the inside is well suited for applications in which the flow direction is radially from the outside to the inside. For applications in which the flow direction is, however, radial from the inside to the outside, such a cylinder sieve is less suitable because it has a very strong tendency to clog.

When producing a cylinder sieve in which the sieve openings enlarge radially from the outside to the inside, the enlargement of these sieve openings can be set to the desired size by means of the gear geometry of at least one gear pair. For this purpose, the effect of the elongation of the outside and the compression of the inside that occurs during the rounding process is specifically strengthened or reduced by the gear geometry.

If, on the other hand, a cylinder mold is to be produced with the production device according to the invention with a flow direction radially from the inside to the outside, in which an enlargement of the sieve openings radially from the inside to the outside is desired, the suitable choice of the gear geometry of the at least one pair of counter-rotating gears can be achieved that despite the effect of stretching on the outside and upsetting on the inside, the height of the wave peaks and the wave troughs of the sheet metal strip windings and thus the amplitude in the radial direction increases outwards and thus the size of the sieve openings in the desired flow direction radially from increases inside out.

With a production device according to the invention, it is thus possible to produce round sieves which are well suited for both directions of flow and show a significantly reduced tendency towards clogging for both directions of flow.

According to a first embodiment of the manufacturing device according to the invention, a first pair of counter-rotating gears is provided, which are arranged and designed above and below the sheet metal strip to be passed through so that the sheet metal strip is thereby transformed into a wave shape with wave crests and with wave troughs as it passes through. Alternatively or in addition to this, a second pair of counter-rotating gears can be provided, which are arranged and designed above and below the sheet metal strip to be passed through so that the sheet metal strip is transformed into a flattened wave shape with flattened wave crests and with flattened wave troughs as it passes through.

Thus, according to the present invention, both a round or rounded wave shape and a flattened wave shape can be produced.

According to a further embodiment of the invention, the teeth and the interdental spaces of the at least one pair of counter-rotating gears are designed to be inclined, in each case based on the axial direction of the respective gear, in order to give the sheet-metal strip, which is formed into a wavy line with crests and troughs, an inclined cross-section in order to the effect of upsetting the inside of the corrugated sheet metal strip and stretching the outside of the corrugated sheet metal strip as it is rounded through the at least two Reinforce or reduce rounding rollers in order to increase the height of the wave crests and the wave troughs of the sheet metal strip windings and to enlarge the screen openings in the flow direction radially outwards, based on the reference plane; or despite the effect of compressing the inside of the corrugated sheet metal strip and stretching the outside of the corrugated sheet metal strip when rounding by the at least two rounding rollers, an increase in the height of the wave crests and the wave troughs of the sheet metal strip windings and an enlargement of the sieve openings in the direction of flow radially inwards on the reference plane.

With such shaped teeth and interdental spaces of the at least one pair of counter-rotating gears, clogging-inhibiting round sieves can be reliably and inexpensively produced both with a flow direction radially outwards and with a flow direction radially inwards.

According to a further embodiment, the manufacturing device also has a welding unit that welds adjacent sheet metal strip turns to one another, in particular welds adjacent sheet metal strip turns to one another on at least some of the adjacent flank sections.

As a result, adjacent sheet metal strip windings are permanently and reliably welded to one another. A change in the sieve openings is reliably avoided.

According to a further embodiment of the invention, a frame attachment unit is also provided which, in particular, braces the sheet metal strip windings against one another in the axial direction.

• Figur 1 zeigt eine schematische Perspektivanischt eines Rundsiebs gemäß einem ersten Ausführungsbeispiel der Erfindung;
• Figur 2 zeigt anhand ihrer Teilfigur Figur 2(a) die schematische Perspektivansicht des Rundsiebs aus Figur 1, anhand ihrer Teilfigur Figur 2(b) eine Draufsicht auf einen Ausschnitt desselben und anhand ihrer Teilfigur Figur 2(c) eine Seitenansicht auf einen Umfangsbereich desselben;
• Figur 3 zeigt anhand ihrer Teilfigur 3(a) eine Seitenansicht der Innenseite eines sinusförmigen Blechstreifen-Windungs-Abschnitts, anhand ihrer Teilfigur 3(b) eine Schnittansicht durch ein Wellental einer Blechstreifen-Windung in einer durch die Symmetrieachse des Rundsiebs verlaufenden Ebene, und anhand ihrer Teilfigur 3(c) eine Seitenansicht der Außenseite eines sinusförmigen Blechstreifen-Windungs-Abschnitts;
• Figur 4 zeigt anhand ihrer Teilfigur 4(a) eine Seitenansicht der Innenseite eines abgeflacht wellenförmigen Blechstreifen-Windungs-Abschnitts, anhand ihrer Teilfigur 4(b) eine Schnittansicht durch ein Wellental einer Blechstreifen-Windung in einer durch die Symmetrieachse des Rundsiebs verlaufenden Ebene, und anhand ihrer Teilfigur 4(c) eine Seitenansicht der Außenseite des abgeflacht wellenförmigen Blechstreifen-Windungs-Abschnitts;
• Figur 5 zeigt anhand ihrer Teilfigur 5(a) eine Seitenansicht eines quadratischen äußeren Umfangsabschnitts des Rundsiebs aus Figur 1, anhand ihrer Teilfigur 5(b) eine Seitenansicht der Außenseite eines sinusförmigen Blechstreifen-Windungs-Abschnitts, anhand ihrer Teilfigur 5(c) eine Abmessungsdarstellung des sinusförmigen Blechstreifen-Windungs-Abschnitts über dessen Höhe und Breite, anhand ihrer Teilfigur 5(d) eine Seitenansicht des sinusförmigen Blechstreifen-Windungs-Abschnitts an der Innenseite, und anhand ihrer Teilfigur 5(e) eine Schnittdarstellung des Rundsiebs durch die Ebene A-A aus der Teilfigur 5(a).
• Figur 6 zeigt anhand ihrer Teilfigur 6(a) eine Seitenansicht eines quadratischen äußeren Umfangsabschnitts des Rundsiebs aus Figur 1, anhand ihrer Teilfigur 6(b) eine Seitenansicht der Außenseite eines abgeflacht wellenförmigen Blechstreifen-Windungs-Abschnitts, anhand ihrer Teilfigur 6(c) eine Abmessungsdarstellung des abgeflacht wellenförmigen Blechstreifen-Windungs-Abschnitts über dessen Höhe und Breite, anhand ihrer Teilfigur 6(d) eine Seitenansicht des abgeflacht wellenförmigen Blechstreifen-Windungs-Abschnitts an der Innenseite, und anhand ihrer Teilfigur 6(e) eine Schnittdarstellung des Rundsiebs durch die Ebene A-A aus der Teilfigur 6(a).
• Figur 7 zeigt eine schematische Darstellung einer Rundsieb-Herstellungsvorrichtung mit einem Blechstreifen, mit einem ersten Paar von gegenläufigen Zahnrädern, mit einem zweiten Paar von gegenläufigen Zahnrädern, mit einer Zahnformdarstellung, und mit Rundungswalzen.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the accompanying figures.

• Figure 1 shows a schematic perspective view of a cylinder mold according to a first embodiment of the invention;
• Figure 2 shows by means of its partial figure Figure 2 (a) the schematic perspective view of the cylinder mold Figure 1 , based on their partial figure Figure 2 (b) a plan view of a section of the same and based on its part of the figure Figure 2 (c) a side view of a peripheral area of the same;
• Figure 3 FIG. 3 (a) shows a side view of the inside of a sinusoidal sheet metal strip winding section, its partial figure 3 (b) shows a sectional view through a corrugation valley of a sheet metal strip winding in a plane running through the axis of symmetry of the cylinder mold, and its partial figure 3 (c) is a side view of the outside of a sinusoidal sheet metal strip winding section;
• Figure 4 FIG. 4 (a) shows a side view of the inside of a flattened, undulating sheet metal strip winding section based on its part figure 4 (b) a sectional view through a wave trough of a sheet metal strip turn in a plane running through the axis of symmetry of the cylinder mold, and, based on its partial figure 4 (c), a side view of the outside of the flattened, undulating sheet metal strip turn section;
• Figure 5 FIG. 5 (a) shows a side view of a square outer circumferential section of the cylinder mold from FIG Figure 1 , based on its sub-figure 5 (b) a side view of the outside of a sinusoidal sheet metal strip winding section, based on its sub-figure 5 (c) a dimensional representation of the sinusoidal sheet metal strip winding section over its height and width, based on its sub-figure 5 (d) a Side view of the sinusoidal sheet metal strip winding section on the inside, and based on its partial figure 5 (e), a sectional view of the cylinder mold through the plane AA from partial figure 5 (a).
• Figure 6 FIG. 6 (a) shows a side view of a square outer circumferential section of the cylinder mold from FIG Figure 1 , based on its partial figure 6 (b) a side view of the outside of a flattened, undulating sheet metal strip winding section, based on its partial figure 6 (c), a dimensional representation of the flattened, undulating sheet metal strip winding section over its height and width, based on its partial figure 6 (d ) a side view of the flattened, wave-shaped sheet metal strip winding section on the inside, and based on its partial figure 6 (e) a sectional view of the cylinder mold through the plane AA from partial figure 6 (a).
• Figure 7 shows a schematic representation of a cylinder mold manufacturing device with a sheet metal strip, with a first pair of counter-rotating gears, with a second pair of counter-rotating gears, with a tooth shape representation, and with rounding rollers.

Figure 1 shows a schematic perspective view of a cylinder mold 2.

The cylinder mold 2 has a cylindrical base body which is formed from a sheet metal strip 2 wound into a multiplicity of sheet metal strip turns. In the present, non-limiting exemplary embodiment, the cylinder mold 2 has about 40 sheet metal strip turns.

The rolled up sheet metal strip 2 has a regular wave shape with alternating wave crests and wave troughs, which in the present exemplary embodiment is approximately sinusoidal.

Except for the top sheet metal strip turn, the sheet metal strip turns are arranged in phase with one another, so that their troughs and their wave crests are arranged at corresponding circumferential positions, so that the troughs of a sheet metal strip turn each in the direction of the wave troughs of the sheet metal strip turn below extend so that the corrugation peaks of a sheet metal strip turn are arranged above the corrugation peaks of the respective sheet metal strip turn below and so that the flank or slope sections between a wave peak and an adjacent wave trough and a wave trough and an adjacent wave crest are each arranged on the corresponding underneath Flank or slope sections of the underlying sheet metal strip winding are in contact.

Welded connections can be provided between some or all of such abutting flank sections. Alternatively or in addition to this, the cylinder mold 2 can also be designed without such welded connections. In this case it is expedient to provide a frame which holds or braces the sheet metal strip turns 4 against one another in the axial direction in order to prevent adjacent sheet metal strip turns from diverging.

Between wave crests lying one above the other and wave troughs lying one above the other of respectively adjacent sheet metal strip windings, sieve openings are formed, which in the side view each have an upper or lower crescent-like shape.

As will be described in detail below, such sieve openings enlarge in the radial direction outward or in the radial direction inward, which in the Figures 1 and 2 is not yet recognizable.

The sheet metal strip windings thus describe a wavy line oscillating around a reference plane, which is in particular spiral-shaped, with wave crests and with wave troughs. The slope of this reference plane and thus the windings of the sheet metal strip is very small and lies in a range of 0-1 °.

The sheet metal strip is made of a metal material, in particular a rust and corrosion-resistant metal material.

The partial figure 2 (a) corresponds to Figure 1 , and to avoid repetition it is not explained again.

In the sub-figures 2 (b) and 2 (c) the wave shape of the sheet metal strip windings 4 is shown with the always recurring sequence: wave crest 6, downwardly directed flank section 8, wave trough 10, upwardly directed flank section 8, wave crest, etc. clearly visible.

In the partial figure 2 (c) it can be clearly seen that the corrugation peaks 6 and corrugation troughs 10 of adjacent sheet metal strip turns 4 are arranged one above the other in the circumferential direction and form crescent-shaped sieve openings 11 between them, and that the respective superimposed flank sections 8 of adjacent sheet metal strip turns 4 lie against each other.

The sub-figures 3 (a) and 3 (c) each show a period of a sinusoidal sheet metal strip winding section 12 from the trough 10 over the rising flank section 8, the crest 6, the falling flank section 8 to the next trough 10, each on the outside ( Figure 3 (c) ) and on the inside ( Figure 3 (a) ). It can be clearly seen that the amplitude of the sheet metal strip winding is higher on the outside than on the inside. In the valley figure 3 (b) shows a sectional illustration through the sinusoidal sheet metal strip winding section 12, specifically through a sectional plane which is perpendicular to the plane of the drawing and which extends through the sinusoidal winding section 12 Figures 3 (a) and 3 (c) The trough 10 located on the right intersects, looking to the left.

It can be clearly seen that the amplitude of the sheet metal strip winding section 12 changes from the inside (in Figure 3 (b) shown on the right) outwards (in Figure 3 (b) shown on the left) enlarged. One made from such sheet metal strip windings as shown in FIG Figure 1 The cylinder sieve 2 produced is thus well suited for a flow direction radially from the inside to the outside, because the sieve openings formed by the opposing corrugation troughs 10 and corrugation peaks 6 of adjacent sheet metal strip turns increase in size in the radial direction from the inside to the outside, and thus the The tendency of such a cylinder to clog is significantly reduced compared to a conventional cylinder.

The reference plane of the sheet metal strip winding 4 and the in Figure 3 The sinusoidal sheet metal strip winding section 12 shown intersects the sheet metal strip winding section 12 centrally in a horizontal left-right direction. In relation to such a reference plane, the height of the wave crests 6 and the wave troughs 10 increases from the inside to the outside in the radial direction.

The representation of the Figure 4 corresponds essentially to illustration 3, the sheet metal strip winding section 14 describing a flattened, undulating course instead of a sinusoidal course.

The wave crests 16 and the wave troughs 20 are therefore not rounded, but flattened, resulting in wider and less high screen openings when a plurality of sheet metal strip windings 14 of the Figure 4 shown type are wound to a substantially cylindrical or substantially frustoconical base body and the wave crests 16 and the wave troughs 18 of adjacent sheet metal strip windings 14 are superimposed and the rising and falling flank sections 18 each bear against each other.

Even with the sectional view of the Figure 4 (b) one can see that the amplitude of the flattened, undulating sheet metal strip turns increases radially from the inside to the outside and thus the height of the wave crests 16 and the wave troughs 18 increases radially from the inside to the outside, based on the horizontal left-right direction, the flattened, undulating sheet metal strip -Winding section 14 centrally intersecting reference plane, and that accordingly the size of the screen openings that are formed when a plurality of sheet metal strip windings of the type as shown in Figure 4 are shown, lie on top of one another.

The angle of inclination of the wave crests 6 and wave troughs 10 radially from the inside to the outside, in each case based on the reference plane, is 1.5 °. The one in the Figures 3 and 4th The opening angle α drawn between the wave valley 20 and the wave crest 16 is thus 3 °.

In Figure 5 (a) a cylinder screen cutout 22 with sinusoidal sheet metal strip windings is shown in a side view from the outside. This clearly shows that the sheet metal strip windings 4 lying one above the other are arranged in phase, the wave troughs 10 of which each form intermediate crescent-shaped screen openings 11, that their wave crests 6 are also arranged one above the other and also essentially form crescent-shaped screen openings 11 between them rising and falling flank sections 8 are each in contact with one another.

The height h of the sieve openings 11 on the outside is 0.25 mm in the present exemplary, non-limiting embodiment, and the area F on the outside, i.e. at the outlet opening of the sieve openings 11, is 0.16 mm in the present exemplary, non-limiting embodiment ² . Of course, other heights and other areas are possible.

According to Figure 5 (b) is again, as in Figure 3 (a) , a period of a sinusoidal sheet metal strip winding section 24 from the wave trough 10 via the rising flank section 8, the wave crest 6, the falling flank section 8 to the next wave trough 10, whereby this is the outside of the sinusoidal sheet metal strip winding section 24 acts.

The thickness d of the sheet metal strip winding section 24 is 0.45 mm in the present exemplary, non-restrictive embodiment, and the stretched one Length l on the inside, that is to say the length of one period of a sinusoidal sheet metal strip winding section 24, is 3.94 mm, and on the outside 4.23 mm.

In the partial figure 5 (d) the sinusoidal sheet metal strip winding section 24 is shown on the inside. It can be clearly seen that the amplitude and the height of the wave crests 6 and the wave troughs 10 are smaller than on the outside.

The angle of inclination of the wave crests 6 and the wave troughs 10 radially from the inside to the outside is in the present exemplary, non-restrictive embodiment, 1.5 °, based on the horizontal reference plane running in the left-right direction. In the dimensional illustration 26, the opening angle α between the wave crest 6 and the wave trough 10 lying next to it is shown, which in the present exemplary, non-limiting embodiment is 3 °.

The height of the amplitude h _i on the inside is 1.56 mm, the height of the amplitude h _a on the outside is 1.75 mm, the width b of the sheet metal strip winding measured in the radial direction is 3.7 mm. These values are only exemplary and not restrictive. Of course, sheet metal strip windings with other dimensions can be provided.

In the partial figure 5 (a) a vertical section line AA is drawn through the wave troughs 10 of the sheet metal strip windings. In the sectional view of the Fig. 5 (e) along the section line AA according to Figure 5 (a) one can clearly see the increase in the height of the wave troughs 10 in the radial direction from the inside to the outside and the enlargement of the sieve openings 11 radially from the inside to the outside.

The partial figure 5 (e) is a schematic representation. The waves overlap over the conical embossing and thus have a balancing effect. The deviation is then minimally different from the cylinder axis.

The sub-figures 6 (a) to (e) largely correspond to the sub-figures 5 (a) to (e), with the sheet metal strip windings not having a sinusoidal shape, but a flattened wave-like shape.

The height h of the sieve opening 11 on the outside is also 0.25 mm, the area F occupied by a sieve opening 11 on the outside is 0.26 mm ² . The stretched length l is 3.83 mm, the width b of the sheet metal strip windings seen in the radial direction is also 3.7 mm. The height h _{i of} the amplitude on the inside is 1.16 mm, the height h _{a of} the amplitude on the outside is 1.35 mm. The stretched length l on the inside is 3.64 mm, the stretched length l on the outside is 3.83 mm, the angle of increase in height of the wave peaks and troughs 16 and 18 with respect to the reference plane running horizontally in the left-right direction is 1 , 5 ° and the opening angle α radially from the inside to the outside is 3 °.

All these dimensions are only exemplary and not restrictive. Of course, other dimensions can be realized.

The circumferential surface occupied on the outside by the sieve openings 11, based on the entire outer circumferential jacket surface, is in accordance with a cylinder sieve with sinusoidal sheet metal strip windings Figure 5 exemplary 16% and for a cylinder mold with flattened, undulating sheet metal strips according to FIG Figure 6 exemplary 24.5%.

Figure 7 shows a schematic illustration of a cylinder mold production device 34 with a sheet metal strip 36, with a first pair of counter-rotating gears 38, with a second pair of counter-rotating gears 40, with a tooth shape representation 44, and with rounding rollers 42.

The mode of operation and the method for producing a cylinder mold according to the invention from a flat sheet metal strip 36 is as follows:
A sheet metal strip 6, in particular a sheet metal strip, the length of which corresponds to the number of corrugated sheet metal strip turns that are wound up to form the desired cylindrical or frustoconical base body, or an endless sheet metal strip which is then cut to length, is a first pair of counter-rotating gears 38 and then one second pair of counter-rotating gears supplied 40.

As it passes between the first pair of counter-rotating gears 38, the flat sheet-metal strip turns into a uniform, rounded, in particular substantially reshaped sinusoidal wave form with wave crests and wave troughs. The teeth of one of the two gears 38 each engage a little into the interdental spaces of the opposing gear 38, and the shape of the teeth is correspondingly rounded.

After passing through the first pair of counter-rotating gears 38, the now corrugated sheet metal strip is passed between the second pair of counter-rotating gears 40 and formed there into a flattened wave shape with flattened wave crests and flattened wave troughs, the amplitude also being reduced here. For this purpose, the teeth of one gear wheel of the gear wheel pair 40 again mesh with the gaps between the teeth of the respective opposing gear wheel, and the corrugated sheet metal strip 36 is fed in such a way that its waveform corresponds in phase with the tooth profile of the second gear wheel pair 40, so that the previously rounded Wave crests and wave troughs are reshaped into flattened wave crests and wave troughs.

In addition, the teeth and / or the spaces between the teeth of at least one of the two gear wheel pairs 38 and 40 can be designed to be inclined in the axial direction of the respective gear wheel in order to transform the sheet metal strip into an inclined wave shape along its width.

This inclination is chosen so that the effect of upsetting the inside of the corrugated sheet metal strip and stretching the outside of the corrugated sheet metal strip is specifically enhanced or reduced during the subsequent rounding by the rounding rollers 42.

As a result, either, despite the effect of upsetting the inside and stretching the outside of the corrugated sheet metal strip when rounding by the rounding rollers 42, an increase in the height of the wave peaks and the wave troughs of the sheet metal strip windings and an enlargement of the sieve openings in the direction of flow radially outward the reference plane.

Or the increase in height of the wave crests and the wave troughs of the sheet metal strip windings and an enlargement of the screen openings in the direction of flow achieved by the effect of compressing the inside and stretching the outside of the corrugated sheet metal strip when rounding by the rounding rollers radial inward tends to be maintained and only increased or decreased.

To a round sieve like in the Figures 4 and 6 described, with the increase in height of the wave crests and troughs radially from the inside to the outside and with the screen openings increasing radially from the inside to the outside, the teeth have at least one of the two gear wheel pairs 38 and 40 and, accordingly, the interdental spaces have a tooth shape, as shown in the tooth shape illustration 44 , with a tooth flank that rises outwards in relation to the radius of curvature, so that the flattened, undulating sheet metal strip has a higher amplitude and thus higher wave crests and troughs on its outside.

If a cylinder mold is to be produced with a flow direction from the outside to the inside, the inclination of the teeth and the interdental spaces of at least one gear pair 38, 40 is to be designed with a smaller, outwardly increasing inclination angle than shown in the tooth shape illustration 44.

The right area of the Figure 7 with the rounding rollers 42 is shown rotated by 90 ° with respect to the gear wheel pairs 38 and 40. This 90 ° rotation is illustrated in FIG. 7 by means of an arrow.

After the straight sheet metal strip 36 has been rolled into a sheet metal strip with a flattened and inclined wave shape by the gear wheel pairs 38 and 40, the rounding rollers 42, which are arranged to the left and right of the continuous, flattened corrugated sheet metal strip 36, round it to a round screen, like it in the Figures 1 , 2 , 4th and 6 is shown.

The flattened corrugated sheet metal strip 36 is wound up into a plurality of sheet metal strip windings which describe a wavy line oscillating around a reference plane with wave crests and with wave troughs in such a way that adjacent sheet metal strip windings lie against one another so that sieve openings are formed in the radial direction.

In one exemplary embodiment, the flattened, corrugated sheet metal strip 36 is wound up to form a base body made up of a multiplicity of wound sheet metal strip turns lying against one another in such a way that the adjacent Sheet metal strip windings lie in phase, so that their wave crests and wave troughs are arranged one above the other and their rising and falling flank sections rest against one another, as shown in the figures described above.

Due to the corresponding preforming of the flattened corrugated sheet metal strip with outwardly rising wave crests and wave troughs, despite the effect of compressing the inside and stretching the outside that occurs during rounding, an increase in the height of the wave crests and the wave troughs of the sheet metal strip windings and an enlargement of the sieve openings in the desired flow direction radially from the inside to the outside, based on the reference plane, achieved.

After completion of the cylinder mold with the desired height and the desired number of turns of sheet metal strips resting against one another, the manufacturing process can be stopped. Either the supplied sheet metal strip is completely wound up or it is cut to length accordingly.

In an exemplary embodiment not shown here, sheet-metal strip windings that are adjacent to one another can be welded to at least some of the areas that are in contact with one another.

In a further exemplary embodiment, not shown here, a frame structure can be mounted on the cylinder screen produced in this way, which supports the sheet metal strip windings in the axial direction or braces them against each other so that their adjacent areas remain permanently in contact.

If a cylinder mold with a sinusoidal wave shape of the rolled up sheet metal strip is to be produced, then the second pair of gears, which is responsible for shaping into a flattened wave-shaped wave shape, can be omitted.

List of reference symbols

• 2 cylinder sieves
• 4 turns of sheet metal strips
• 6 wave crests
• 8 flank sections
• 10 wave troughs
• 11 sieve openings
• 12 sinusoidal sheet metal strip winding section
• 14 flattened, wave-shaped sheet metal strip winding section
• 16 flattened wave crest
• 18 flank sections
• 20 flattened wave trough
• 22 Section of round sieve with sinusoidal sheet metal strip windings
• 24 sinusoidal sheet metal strip winding section
• 26 Dimensions
• 28 Section of round sieve with flattened, wave-shaped sheet metal strip windings
• 30 flattened, undulating sheet metal strip winding section
• 32 Dimensions
• 34 Cylinder Sieve Manufacturing Apparatus
• 36 metal strips
• 38 first pair of counter-rotating gears for waveform and / or bevel
• 40 second pair of counter-rotating gears for flattening and / or beveling
• 42 rounding rollers
• 44 Tooth shape representation

Claims (12)

1. A manufacturing device for a circular screen, comprising a feed unit for a sheet-metal strip (36);
   at least one pair of counter-rotating gear wheels (38, 40) which are arranged and formed above and below the sheet-metal strip (36) to be passed therethrough in such a manner that the sheet-metal strip (36) upon passage therethrough is converted into a wave shape with wave crests (6) and wave troughs (10); and
   at least two rounding rollers (42) which are designed and arranged beside the sheet-metal strip (36) passing therethrough in such a manner that the sheet-metal strip (36) is wound into a plurality of sheet-metal strip windings (4) which describe a wavy line having wave crests (6) and wave troughs (10) and oscillating about a reference plane; and
   that adjacent sheet-metal strip windings (4) abut one another such that screen openings (11) are formed in radial direction;
   characterized in that the at least one pair of counter-rotating gear wheels (38, 40) has a gear wheel geometry which changes the cross-section of the sheet-metal strip (36) such that, after passage of the sheet-metal strip (36) through the at least two rounding rollers (42), the height of the wave crests (6) and the wave troughs and thus the amplitude (10) of the sheet-metal strip windings (4), in relation to the reference plane, increases radially outwards, so that the size of the screen openings (11) increases radially outwards in the direction of flow therethrough; or the height of the wave crests (6) and the wave troughs (10) and thus the amplitude of the sheet-metal strip windings (4), in relation to the reference plane, increases radially inwards, so that the size of the screen openings (11) increases radially inwards in the direction of flow therethrough.
2. The manufacturing device for a circular screen according to claim 1, wherein a first pair of counter-rotating gear wheels (38) is provided, which are designed and arranged above and below the sheet-metal strip (36) to be passed therethrough such that the sheet-metal strip (36) upon passage therethrough is converted into a wave shape with wave crests (6) and wave troughs (10); and/or
   wherein a second pair of counter-rotating gear wheels (40) is provided, which are designed and arranged above and below the sheet-metal strip (36) to be passed therethrough such that the sheet-metal strip (36) upon passage therethrough is converted into a flattened wave shape with flattened wave crests (16) and with flattened wave troughs (20).
3. A manufacturing device for a circular screen according to claim 1 or 2, wherein the teeth and the spaces between the teeth of the at least one pair of counter-rotating gear wheels (38, 40) are inclined, in each case with respect to the axial direction of the respective gear wheel, in order to give an inclined cross section to the sheet-metal strip (36) that is converted into a wavy line with wave crests (6) and wave troughs (10),
   so as to increase or decrease the effect of upsetting the inside of the corrugated sheet-metal strip (36) and of stretching the outside of the corrugated sheet-metal strip (36) when rounding through the at least two rounding rollers (42) is performed, in order achieve an increase in height of the wave crests (6) and the wave troughs (10) of the sheet-metal strip windings (4) as well as an enlargement of the screen openings (11) radially outwards in the direction of flow therethrough, with respect the reference plane; or
   so as achieve an increase in height of the wave crests (6) and the wave troughs (10) of the sheet-metal strip windings (4) and an enlargement of the screen openings (11) radially inwards in the direction of flow therethrough, with respect to the reference plane, despite the effects of upsetting the inside of the corrugated sheet-metal strip (36) and stretching the outside of the corrugated sheet-metal strip (36) when rounding through the at least two rounding rollers (42) is performed.
4. A circular screen, comprising
   a substantially cylindrical and/or substantially truncated conical base body, which is formed from a sheet-metal strip wound into a plurality of sheet-metal strip windings (4);
   wherein the sheet-metal strip describes a wavy line having wave crests (6) and wave troughs (10) and oscillating about a reference plane; wherein respective adjacent sheet-metal strip windings (4) abut one another such that screen openings (11) are formed in the radial direction; and characterized in that the height of the wave crests (6) and the wave troughs (10) and thus the amplitude of the sheet-metal strip windings (4), in relation to the reference plane, increases radially outwards so that the size of the screen openings (11) increases radially outwards in the direction of flow therethrough; or
   wherein the height of the wave crests (6) and the wave troughs (10) and thus the amplitude of the sheet-metal strip windings (4), in relation to the reference plane, increases radially inwards so that the size of the screen openings (11) increases radially inwards in the direction of flow therethrough.
5. The circular screen according to claim 4,
   wherein the circular screen (2) is a circular screen having a direction of flow from the inside to the outside; and
   wherein the height of the wave crests (6) and the wave troughs (10) of the sheet-metal strip windings (4), in relation to the reference plane, increases radially outwards so that the size of the screen openings (11) increases from the inside radially outwards in the direction of flow therethrough.
6. The circular screen according to claim 5,
   wherein the circular screen is a circular screen having a direction of flow from the outside to the inside; and
   wherein the height of the wave crests (6) and the wave troughs (10) of the sheet-metal strip windings (4), in relation to the reference plane, increases radially inwards so that the size of the screen openings (11) increases from the outside radially inwards in the direction of flow therethrough.
7. The circular screen according to any of claims 4 to 6,
   wherein the oscillating wavy line with wave crests and wave troughs comprises flattened with wave crests (16) and flattened wave troughs (20).
8. The circular screen according to any of claims 4 to 7,
   wherein the oscillating wavy line with wave crests and with wave troughs has substantially a sinusoidal shape with round or rounded wave crests (6) and with round or rounded wave troughs (10).
9. The circular screen according to any of claims 4 to 8,
   wherein respective adjacent sheet-metal strip windings (4) have their flank sections (8) abutting one another between the wave crests (6) and the wave troughs (10) such that, in the radial direction, screen openings (11) between the wave crests (6) and the wave troughs (10) are each formed by respective sheet-metal strip windings (4) lying one above the other.
10. The circular screen according to any of claims 4 to 9,
    wherein the circumferential surface formed by the screen openings (11), in particular by the respective smallest openings of the screen openings (11), is 15 to 50% of the screen opening surface of the circular screen.
11. The circular screen according to any of claims 4 to 10,
    wherein respective adjacent sheet-metal strip windings (4) abut one another and the circular screen further comprises a frame holding the respective adjacent sheet-metal strip windings (4) against one another in an abutting position.
12. The circular screen according to any of claims 4 to 11,
    wherein respective adjacent sheet-metal strip windings (4) are welded to one another; and/or wherein respective adjacent sheet-metal strip windings (4) are welded to one another on at least part of the mutually abutting flank sections (8) of respective adjacent sheet-metal strip windings (4).

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