DE102014009704B3 - Plastic screen covering for a screening machine for classifying in particular coarse-grained bulk material - Google Patents

Abstract

The invention relates to a plastic screen covering for a screening machine for classifying, in particular, coarse-grained bulk material, the 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 regions (7a, 7b), the two opposite end regions (7a, 7b; 7a ', 7b') of the mesh (1a; 1b; 1c; 1d) having rounded corner regions (9a ', 9b', 9a ' ', 9b' '); 9a '', 9b '') are formed adjacent straight edge portions (x and y; y and z), the rounded corner portions (9a ', 9b'; 9a '', 9b '') of adjacent straight edge portions (x and y; y and z) a ratio of mesh width (b) extending in the transverse direction (Q) of the screen mesh (1 '; 1' ') and a radius (r) of the corner region (9a', 9b '; 9a' ', 9b' ') from b / r = 2 to 10.

Description

The invention relates to a plastic screen covering for a screening machine for classifying in particular coarse-grained bulk material, the screen mesh formed by longitudinal webs and transverse webs extend longitudinally or transversely to the Siebarbeitsbewegungsrichtung and have mirror-symmetrically opposite end portions in the longitudinal 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 interest here type usually do not consist of metal, but of plastic, in particular polyurethane, and have a variety of openings, so-called sieve mesh through which the sieved bulk material falls through, whereas the relatively coarser 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, whose regularly arranged on longitudinal and transverse webs Siebmaschen have an 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.

Furthermore, the beats US 4 062 769 A before, arcuate form opposite end portions of Siebmaschen.

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. It is a further object of the invention to provide a sifting machine in which downtime for changing the Siebbelags over the prior art are reduced.

The objects are achieved on the basis of a screen covering according to the preamble of claim 1 in conjunction with its characterizing features or with regard to the screening machine with the features according to claim 12. 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 as straight edge portions meeting each other with rounded corner portions, the rounded corner portions of adjacent straight edge portions having a ratio of mesh width extending in the transverse direction of the mesh and a radius of the corner portion of Figs 10 have.

In other words, the solution according to the invention overcomes the above-described problem of rectangular meshes by their head ends are designed specially rounded. 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 one embodiment of the prior art, the arcuate end portions of the meshes are each formed semicircular and thus have a ratio of transverse in the Siebmasche mesh width and the radius of the corner 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 Siebmaschen generated by semicircular end regions are thus particularly stable, but require a higher material requirement in series arrangement in the nodes of adjacent Siebmaschen.

According to 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 portion 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. As a result of the fact that the material requirement tends to be lower than that of the prior art described above, the specific open screen area and thus the throughput of screenings continue to increase.

The length of the screen mesh is preferably in the range of 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 having a screen lining thickness in the range of 0.5 to 5 mm.

According to a further measure improving the invention, it is proposed that the sieve mesh be conical in cross-section and extend from 0.5 to 20 ° under an edge angle widening in the direction of diarrhea of the sieve material. 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.

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:

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

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

3 FIG. 2 is a schematic plan view of a selection of meshes according to an embodiment of the prior art. FIG.

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

5 1 is a schematic partial view of a sieve mesh according to an embodiment of the prior art,

6 1 is a schematic partial view of a sieve mesh according to a first variant,

7 1 is a schematic partial view of a sieve mesh according to a second variant,

8th a schematic plan view of a selection of Siebmaschen with a mesh width identical web width, and

9 a schematic plan view of a selection of Siebmaschen with a compared to 8th reduced web width.

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

To reinforce the Kunststoffsiebbelags extend 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 coating. The reinforcing threads 2 thereby run within the web area next to the Siebmaschen 1 ,

According to the alternative embodiment according to 2 are reinforcing threads 2 ' 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 a wedge-shaped shape seen in cross-section.

After the in 3 illustrated embodiment of the prior art for a plastic screen covering with a regular grid structure are the exemplary Siebmaschen 1a and 1b such as 1c and 1d arranged one above the other in the longitudinal direction L. In the transverse direction Q are the Siebmaschen 1a and 1c such as 1b and 1d arranged exactly next to each other. Schematically, only a portion of the Siebmaschen the Kunststoffsiebbelages are shown here.

The row of meshes 1a and 1c gets from the row of sieve meshes 1b and 1d through longitudinal webs 4 divided. In each case adjacent Siebmaschen 1a and 1c such as 1b and 1d be through crossbars 5 shared by each other. As a result of the regular grid structure of the mesh arrangement created in this way, the longitudinal webs are created in the intersection area 4 with the crossbars 5 in each case a four-sided node K1, which is indicated here by a dashed circle.

Every sieve mesh 1c (Exemplary) has in the longitudinal direction L opposite each other semicircular end regions 7a and 7b on which in the connecting middle area 6 by mutually parallel edge portions 8a . 8b connected to each other.

The sectional view AA according to 4 clarifies that the mesh 1b (by way of example) extends from the screen top side to the bottom side of the sieve in a widening manner at an edge angle β, in order to jam sieved particles within the sieve mesh 1b ' to avoid.

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

To 6 have rounded corner areas 9a ' and 9b ' coincident straight edge sections x and y and - opposite - y and z a ratio of transverse direction Q of the screen mesh 1' running mesh width b and a radius r of the corner area 9a ' respectively. 9b ' from b / r = 3 up.

To 7 results in an even further adapted to the rectangular envelope geometry mesh shape by the rounded end 9a '' such as 9b '' coincident straight edge portions x and y and y and z a ratio in the transverse direction Q of the mesh screen 1'' running mesh width b and a radius r of the corner area 9a '' respectively. 9b '' of b / r = 10.

In the arrangement of Siebmaschen each other according to 8th are adjacent rows of transversely juxtaposed meshes 1a ' . 1c ' respectively. 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 arrangement of Siebmaschen each other according to 9 is the web width b '' compared to the mesh width b reduced to a lower value. This results in a larger specific Sieboberfläche by correspondingly smaller web widths.

The invention is not limited to the embodiments described above. On the contrary, modifications are conceivable which are included in the scope of protection of the following claims. So it is also possible, for example, reinforcing threads 2 only in the longitudinal direction L or in the transverse direction Q and by several Siebmaschen spaced apart from each other to integrate. The rail-shaped Materialanformungen 3 can thereby material reinforcements in the area guided by reinforcing threads 2 form.

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 (12)

Plastic screen covering for a screening machine for classifying, in particular, coarse-grained bulk material, whose longitudinal webs ( 4 ) and transverse webs ( 5 ) formed Siebmaschen ( 1 ) extending longitudinally or transversely to the Siebarbeitsbewegungsrichtung (A) and in the longitudinal direction (L) mirror-symmetrically opposite end portions ( 7a . 7b ), characterized in that the two opposite end regions ( 7a . 7b ; 7a ' . 7b ' ) of the mesh ( 1a ; 1b ; 1c ; 1d ) than with rounded corners ( 9a ' . 9b '; 9a '' . 9b '' ) are formed adjacent straight edge portions (x and y, y and z), wherein the rounded corner areas ( 9a ' . 9b '; 9a '' . 9b '' ) of juxtaposed straight edge sections (x and y, y and z) a ratio of transversely (Q) of the mesh ( 1'; 1'' ) running 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 two end regions ( 7a . 7b ) of the mesh ( 1a ; 1b ; 1c ; 1d ) ( 6 ) of two mutually parallel edge portions ( 8a . 8b ) consists. Plastic sieve covering according to claim 1, characterized in that the length of the sieve mesh ( 1a ; 1b ; 1c ; 1d ) is in the range of 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 of 0.5 to 5 mm. Plastic sieve covering according to claim 1, characterized in that the sieve mesh ( 1a ; 1b ; 1c ; 1d ) in the cross-section conically under a extending in the direction of diarrhea of Siebguts edge angle (β) of 5 ° to 20 °. Plastic sieve covering according to claim 1, characterized in that by the longitudinal webs ( 4 ) and transverse webs ( 5 ) formed sieve structure is made of a polyurethane material. Plastic sieve according to claim 1, characterized in that at least by a part of the longitudinal webs ( 4 ) and / or transverse webs ( 5 ) within the polyurethane material reinforcing threads ( 2 ) extend from a fiber material. Plastic sieve covering according to claim 1, characterized in that on the sieve top side in the region along at least one reinforcing thread ( 2 ) a wedge-shaped in cross section, arcuate or polygonal Materialanformung ( 3 ) is arranged for guiding the Siebguts. Plastic sieve covering according to claim 1, characterized in that the sieve meshes ( 1a ; 1b ; 1c ; 1d ) are juxtaposed and stacked in series to form a regular lattice structure. Plastic sieve covering according to claim 1, characterized in that adjacent rows in the longitudinal direction (L) of sieve meshes arranged one above the other ( 1a ; 1b ; 1c ; 1d ) are offset from one another. Plastic sieve covering according to claim 1, characterized in that adjacent rows in the transverse direction (Q) of adjoining sieve meshes (Q) 1a ; 1b ; 1c ; 1d ) are offset by up to a mesh width (b) to each other. 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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