EP2962772A1 - Plastic screen lining for a screen for classifying in particular coarse-grained material to be screened - Google Patents

Abstract

The invention relates to a plastic screen covering for a screening machine for classifying, in particular, coarse-grained screenings whose screen meshes (1) formed by longitudinal webs (4) and transverse webs (5) extend longitudinally or transversely to the direction of wire movement (A) and mirror-symmetrically in the longitudinal direction (L) opposite end portions (7a, 7b), wherein the two opposite end portions (7a, 7b; 7a ', 7b') of the screen mesh (1a; 1b; 1c; ld) arcuate or with rounded corner regions (9a ', 9b', 9a ", 9b") are formed on adjacent edge portions (x and y; y and z).

Description

The invention relates to a plastic screen covering for a screening machine for classifying, in particular, coarse-grained bulk material, the screen meshes formed by longitudinal webs and transverse webs extend longitudinally or transversely to the direction of wire movement and each have a mirror-symmetrical shape both in the longitudinal direction and in the transverse direction. In addition, the invention also relates to a sieve machine comprising this plastic sieve covering with an electrically operated mechanical oscillating drive.

The field of application of the invention extends to the screening of bulk material, which may be in the form of a dry solid or in a suspension. In particular, the solution according to the invention can also be used in the field of treatment of sand, slags, salts and minerals. Screen coverings of the type of interest here are usually not made of metal, but of plastic, in particular polyurethane, and have a plurality of openings, so-called sieve mesh through which the sieved bulk material falls through, whereas the relatively coarse-grained residue on the Sieboberseite remains. The Siebarbeitsbewegung in the form of a main back and shake the Siebbelags is performed by a known screening machine, in addition to the receiving box for the screenings usually an electrically operated mechanical vibration drive is mounted. The plastic sieve is interchangeable mounted in the area of the bottom of the sieve box.

From the WO 2011/133 238 A1 is a Kunststoffsiebbelag made of polyurethane material, its regularly on longitudinal and transverse webs separately arranged Siebmaschen a have elongated rectangular shape. In the webs reinforcing threads are molded from a fiber material to increase the tensile strength of the material.

In sieve operation, a workload is exerted on the rectangular sieve meshes, as a result of which critical notch stresses occur, in particular in the rectangular corners of the rectangular sieve meshes, which can lead to cracking. This causes premature wear of the screen lining.

In order to solve this problem, it has hitherto been attempted to reinforce the plastic material at the points of intersection of the stitches, in particular by broadening the webs between the stitches. However, this measure leads to a reduction of the specific open screen area and thus to a reduction of the throughput through the screen covering.

It is therefore an object of the present invention to provide a Kunststoffsiebbelag, which is characterized by a high specific open screen area and a long service life.

The object is achieved on the basis of a screen covering according to the preamble of claim 1 in conjunction with its characterizing features. The following dependent claims give advantageous developments of the invention.

The invention includes the technical teaching that the two opposite end portions of the sieve mesh are formed arcuate or with rounded rear portions of successive straight edge portions.

In other words, the solution according to the invention overcomes the problem of rectangular meshes described above by making their head ends specially rounded are. Such shaped meshes make it possible to optimize the material use of plastic material at the intersections of the sieve mesh, as due to the low notch effect in the mesh edges of the material used can be reduced. In particular, in fiber-reinforced Kunststoffverbundsiebbelägen this measure has a lifetime extending due to the low Siebbelagdicke and allows a larger specific open screen area.

Thus, the solution according to the invention leads to more stable screen coverings and a larger screen throughput. According to a first preferred embodiment of the invention, it is proposed that the arcuate end regions of the screen meshes are each semicircular and thus have a ratio of mesh width extending in the transverse direction of the mesh mesh and the radius of the corner region of b / r = 2. By means of this semicircular design, a tangentially uniform transition of the end region to the middle region of the screen mesh is achieved, which preferably consists of mutually parallel edge sections. The screen meshes produced by semicircular end regions are therefore particularly stable, but require a higher material requirement in the arrangement of rows in the intersections of adjacent screen meshes.

According to a second preferred embodiment of the invention, the rounded corner portions of adjacent straight edge portions have a ratio of mesh width extending in the transverse direction of the mesh and a radius of the corner region of b / r = 2 to 10. Thus, with rounded end regions, this mesh shape is oriented closer to the rectangular basic shape of the sieve mesh, which forms the shell geometry for this purpose. Experiments have shown that the claimed ratio range of the mesh width to the radius represents an optimum of long service life and material requirements for the plastic screen covering. By the opposite of the above described first embodiment tends to lower material requirements continue to increase the specific open screen area and thus the throughput of screenings.

The length of the screen mesh is preferably in the range between 0.3 to 20 mm and is always greater than the mesh width. As a result, the generously elongated mesh shape is achieved. Larger lengths for coarser screenings are at the expense of the service life of Siebbelags; smaller lengths of the sieve mesh are not exactly reproducible in the inventive sieve mesh form production technology, and therefore not recommended.

A screen mesh formed with the above dimensional ranges is particularly suitable for plastic screen coverings with a screen lining thickness in the range between 0.5 to 5 mm.

According to a further measure improving the invention, it is proposed that the sieve mesh taper in cross section and extend between 0.5 ° to 20 ° in the diagonal direction of the screen material widening edge angle. This edge angle prevents jamming of screen particles within the screen mesh. In this case, a tendency of lower edge angle of the service life of the plastic screen covering benefits.

The plastic sieve is preferably made of polyurethane material and is formed by longitudinal webs and transverse webs, so that there is a kind of lattice structure.

At least through a part of the longitudinal webs and / or transverse webs reinforcing threads can run from a fiber material within the polyurethane material. Due to the reinforcing threads, the tensile strength of the Kunststoffsiebbelags and its load capacity increases.

As a further measure improving the invention, it is proposed that a wedge-shaped, arcuate or polygonal material configuration for conducting screenings be arranged on the screen top side and preferably in the region along at least one reinforcing thread. Through the management of the Siebguts the throughput is increased and the inner reinforcing threads are surrounded by sufficient plastic material.

According to a preferred embodiment, the meshes are arranged side by side and one above the other in series, so that a strictly regular lattice structure results. This makes it possible to form particularly stable nodes between the meshes. Alternatively, however, it is also possible to arrange adjacent rows of longitudinally stacked sieve meshes offset from one another or to arrange adjacent rows in the transverse direction of juxtaposed sieve meshes up to a mesh width offset from one another. In this way, the web widths of adjacent Siebmaschen can be varied and adapted to different load situations and Siebeigenschaften.

Figur 1

eine schematische perspektivische Ansicht eines Kunststoffsiebbelags in einer ersten Ausführungsform,

Figur 2

eine schematische perspektivische Ansicht eines Kunststoffsiebbelags in einer zweiten Ausführungsform,

Figur 3

eine schematische Draufsicht einer Auswahl von Siebmaschen in einer ersten Ausführungsform,

Figur 4

eine Detaildarstellung im Schnitt A-A einer Siebmasche aus Figur 3,

Figur 5

eine schematische Teilansicht einer Siebmasche gemäß einer ersten Variante,

Figur 6

eine schematische Teilansicht einer Siebmasche gemäß einer zweiten Variante,

Figur 7

eine schematische Teilansicht einer Siebmasche gemäß einer dritten Variante,

Figur 8

eine schematische Draufsicht einer Auswahl von Siebmaschen gemäß einer zweiten Ausführungsform, und

Figur 9

eine schematische Draufsicht einer Auswahl von Siebmaschen gemäß einer dritten Ausführungsform.

Further measures improving the invention will be described in more detail below together with the description of preferred embodiments of the invention with reference to FIGS. It shows:

FIG. 1

a schematic perspective view of a Kunststoffsiebbelags in a first embodiment,

FIG. 2

a schematic perspective view of a Kunststoffsiebbelags in a second embodiment,

FIG. 3

a schematic plan view of a selection of meshes in a first embodiment,

FIG. 4

a detailed representation in section AA of a sieve mesh FIG. 3 .

FIG. 5

1 is a schematic partial view of a sieve mesh according to a first variant,

FIG. 6

1 is a schematic partial view of a sieve mesh according to a second variant,

FIG. 7

1 is a schematic partial view of a screen mesh according to a third variant,

FIG. 8

a schematic plan view of a selection of Siebmaschen according to a second embodiment, and

FIG. 9

a schematic plan view of a selection of Siebmaschen according to a third embodiment.

According to FIG. 1 a plastic sieve made of polyurethane in rows arranged side by side sieve meshes 1, each having both in the longitudinal direction L and in the transverse direction Q has a mirror-symmetrical shape. The meshes 1 extend longitudinally to the Siebarbeitsbewegungsrichtung A, which is produced by a - not shown - screening machine.

To reinforce the Kunststoffsiebbelags extending in the longitudinal direction L as well as in the transverse direction Q a plurality of mutually parallel reinforcing threads 2 made of a fiber material through the plastic screen covering. The reinforcing threads 2 run inside the web area next to the screen meshes 1.

According to the alternative embodiment according to FIG. 2 Reinforcement threads 2 'are provided only in the longitudinal direction L of the Kunststoffsiebbelags. At the Sieboberseite are along the reinforcing threads 2 'rail-like Materialanformungen 3 arranged. The rail-like Materialanformungen 3 have seen in cross section a wedge-shaped shape.

After the in FIG. 3 shown first embodiment for a plastic screen with a regular grid structure, the exemplary Siebmaschen 1a and 1b and 1c and 1d in the longitudinal direction L are arranged one above the other. In the transverse direction Q, the meshes 1a and 1c and 1b and 1d are arranged exactly next to one another. Schematically, only a portion of the Siebmaschen the Kunststoffsiebbelages are shown here.

The row of wire meshes 1a and 1b is divided by the row of wire meshes 1c and 1d by longitudinal webs 4. In each case adjacent sieve meshes 1a and 1c and 1b and 1d are divided by transverse webs 5 from each other. As a result of the regular grid structure of the mesh arrangement created in this way, a four-sided node K1, which is indicated here by a dashed circular line, is formed in each case in the crossing region of the longitudinal webs 4 with the transverse webs 5.

Each screen mesh 1c (by way of example) has in the longitudinal direction L opposite semicircular end regions 7a and 7b, which are connected to one another in the middle region 6 connecting them by mutually parallel edge sections 8a, 8b.

The sectional view AA according to FIG. 4 illustrates that the Siebmasche 1b (exemplary) from the Sieboberseite to the bottom of the sieve extending conically widening at an edge angle β to avoid jamming of sieved particles within the sieve mesh 1c '.

To FIG. 5 the semicircular end region 7a (by way of example) of a sieve mesh 1 results from a ratio of mesh width b running in the transverse direction Q of the sieve mesh 1 and the radius r of the corner region 9 of b / r = 2.

To FIG. 6 have rounded corner regions 9a 'and 9b' of meeting straight edge sections x and y and - opposite - y and z a ratio of transverse width Q of Siebmasche 1 'extending mesh width b and a radius r of the corner region 9a' and 9b 'of b / r = 3 on.

To FIG. 7 a mesh shape adapted even further to the rectangular envelope geometry results by the rounded end region 9a "and 9b" of adjacent straight edge sections x and y and y and z a ratio of transverse direction Q of the screen mesh 1 "extending mesh width b and a radius r of the corner region 9a "or 9b" of b / r = 10.

In the embodiment according to FIG. 8 adjacent rows of transversely juxtaposed Siebmaschen 1a ', 1c' and 1b ', 1d' offset by a whole mesh width b to each other, so that the web width b 'corresponds to the mesh width b.

In an alternative embodiment according to FIG. 9 the web width b "is reduced to a smaller value than the stitch width b, which results in a larger specific screen surface due to correspondingly smaller web widths.

The invention is not limited to the embodiments described above. On the contrary, modifications are conceivable which are included within the scope of the following claims. For example, it is also possible to integrate reinforcing threads 2 only in the longitudinal direction L or in the transverse direction Q and spaced apart by a plurality of meshes. The rail-shaped Materialanformungen 3 can form reinforcements in the area guided through reinforcing threads 2.

LIST OF REFERENCE NUMBERS

1

screen mesh

2

reinforcing thread

3

material accumulation

4

longitudinal web

5

crosspiece

6

the central region

7

end

8th

edge portion

9

corner

L

longitudinal direction

Q

transversely

A

Siebarbeitsbewegungsrichtung

b

mesh width

r

Radius of the corner area

x

first edge section

y

second edge portion

z

third edge section

β

edge angle

K1

Node, four sided

K2

Node, three-sided

Claims (14)

Plastic sieve covering for a screening machine for classifying, in particular, coarse-grained sieved material, the sieve meshes (1) formed by longitudinal webs (4) and transverse webs (5) extend longitudinally or transversely to the sieving movement direction (A) and in the longitudinal direction (L) have mirror-symmetrically opposite end regions (7a , 7b),
characterized in that the two opposite end regions (7a, 7b; 7a ', 7b') of the sieve mesh (1a; 1b; 1c; 1d) meet in an arc shape or with rounded corner regions (9a ', 9b'; 9a ", 9b") straight edge portions (x and y, y and z) are formed. Plastic screen covering according to claim 1,
characterized in that the arcuate end regions (7a, 7b) are each semicircular and a ratio of transverse width (Q) of the screen mesh (1) extending mesh width (b) and radius (r) of the corner region (9) of b / r = 2 have. Plastic screen covering according to claim 1,
characterized in that the rounded corner regions (9a ', 9b', 9a ", 9b") of adjacent straight edge sections (x and y; y and z) have a ratio of transverse direction (Q) of the screen mesh (1 ', 1 ") Mesh width (b) and a radius (r) of the corner region (9a ', 9b', 9a ", 9b") of b / r = 2 to 10. Plastic screen covering according to claim 1,
characterized in that the central region (6) connecting the two end regions (7a, 7b) of the sieve mesh (1a; 1b; 1c; 1d) consists of two edge sections (8a, 8b) running parallel to one another. Plastic screen covering according to claim 1,
characterized in that the length of the screen mesh (1a; 1b; 1c; 1d) is in the range between 0.3 to 20 mm, which is always greater than the mesh width (b). Plastic screen covering according to claim 1,
characterized in that the Siebbelagdicke is in the range between 0.5 to 5 mm. Plastic screen covering according to claim 1,
characterized in that the sieve mesh (1a; 1b; 1c; 1d) is conical in cross-section and extends between 5 ° to 20 ° under an edge angle (β) which widens in the direction of passage of the screened material. Plastic screen covering according to claim 1,
characterized in that the screen structure formed by the longitudinal webs (4) and transverse webs (5) is made of a polyurethane material. Plastic screen covering according to claim 1,
characterized in that extend at least by a part of the longitudinal webs (4) and / or transverse webs (5) within the polyurethane material reinforcing threads (2) made of a fiber material. Plastic screen covering according to claim 1,
characterized in that a wedge-shaped, arcuate or polygonal Materialanformung (3) for guiding the Siebguts is arranged on the Sieboberseite in the region along at least one reinforcing thread (2). Plastic screen covering according to claim 1,
characterized in that the sieve meshes (1a; 1b; 1c; 1d) are arranged side by side and one above the other in series to form a regular lattice structure. Plastic screen covering according to claim 1,
characterized in that adjacent rows in the longitudinal direction (L) of sieve meshes (1a, 1b, 1c, 1d) arranged one above the other are offset relative to one another. Plastic screen covering according to claim 1,
characterized in that adjacent rows in the transverse direction (Q) of adjacent sieve meshes (1a; 1b; 1c; 1d) are arranged offset from each other by up to one mesh width (b). Screening machine for classifying in particular coarse-grained screenings with an electrically operated mechanical oscillating drive, comprising an exchangeable plastic screen covering according to one of the preceding claims.

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