Sieve

Abstract

Sieve comprising a sieve body (1), a plurality of sieve holes (2) penetrating the sieve body (1) and opening onto a sieve body surface (1.1) of the sieve body (1), and wear protection beads (3) associated with the sieve holes (2) and arranged on the sieve body surface (1.1), characterized in that a safety area (1.2) leaving the sieve body surface (1.1) free is provided between a hole edge (2.1) of the sieve hole (2) and the wear protection bead (3).

Description

The invention relates to a sieve according to the preamble of claim 1. A sieve of the type mentioned above is known from document DE 25 32 379 A1. This sieve consists of a sieve body, a plurality of sieve holes penetrating the sieve body and opening onto a sieve body surface, and wear-resistant beads associated with the sieve holes and arranged on the sieve body surface. A very similar solution is also known from document DE 197 19 482 C2. These types of screens are used in the steel industry for screening highly abrasive bulk materials such as coke, ore, or similar substances. Therefore, they must be very wear-resistant to deliver good screening results, at least for a certain period of time. Wear, such as edge rounding or widening, on these screens causes bulk materials to pass through that should not have, which in turn has a massively negative impact on process efficiency. The invention is based on the objective of further improving a sieve of the type mentioned above. In particular, a particularly reliable sieve is to be created. This problem is solved with a sieve of the type mentioned at the outset by the features listed in the characterizing portion of claim 1. According to the invention, a safety area is provided between at least one edge of the sieve hole and the wear protection bead, leaving the sieve body surface uncovered. In other words, the solution according to the invention is characterized by the fact that a safety zone is provided at the edge of the hole, thus leaving the edge of the hole completely free; consequently, the wear-resistant bead is arranged at a (certain) distance from the edge of the hole. This feature ensures that the size of the sieve hole, which is so important for the sieving process, is not altered when the wear-resistant bead is applied. This risk exists with the prior art mentioned above, since it is practically impossible to apply the wear-resistant bead precisely at the edge of the sieve hole with respect to the hole size. In contrast, the safety zone provided by the invention ensures that the sieve hole remains exactly the same size after the wear-resistant bead has been applied as it was before.The probability that, in all of this, a bulk material has a size that is larger than the sieve hole but smaller than the distance between two wear protection beads is comparatively low, i.e. the edges of the sieve holes are very well protected despite the safety area according to the invention, which is so important for the damage-free application of the wear protection beads. Other advantageous embodiments of the sieve according to the invention result from the dependent claims. For the sake of completeness, reference is also made to document DE 2 318 601 C3, from which a solution is known in which the sieve holes are subsequently cut out by plasma cutting or the like; in which, however, the aforementioned wear protection beads are completely absent. The sieve according to the invention, including its advantageous further developments according to the dependent claims, is explained in more detail below with reference to the graphic representation of a preferred embodiment. It schematically shows Fig. 1 in top view the sieve with the safety area according to the invention; and Fig. 2 in section along line AA the sieve with the safety area according to Fig. 1 . The sieve shown in the figures consists, in a known manner, of a sieve body 1, a plurality of sieve holes 2 penetrating the sieve body 1 and opening onto a sieve body surface 1.1 of the sieve body 1, and wear protection beads 3 associated with the sieve holes 2 and arranged on the sieve body surface 1.1. It is preferably provided that the sieve body 1 is made of metal, preferably of sheet steel or cast metal. Furthermore, it is preferably provided that the sieve body 1 is designed as a preferably flat plate. In particular with reference to Fig. 2 and to ensure good removal of material already sieved on the sieve body surface 1.1, it is preferably provided that the sieve holes 2 have a cross-section that increases in size from the sieve body surface 1.1 into the sieve body 1. As can also be clearly seen from Fig. 1, it is further preferred that either the sieve holes 2 and / or the wear protection beads 3 have an elongated cross-section. Furthermore, it is preferably provided that the sieve holes 2 have a teardrop shape in cross-section, and it is particularly preferably provided that the teardrop-shaped cross-section, viewed oriented towards a main material conveying direction (see the arrow on the left in Fig. 1), is initially narrower and later becomes wider. Regarding the geometric arrangement, it is also preferably provided that the sieve holes 2 and / or the wear protection beads 3 are optionally arranged in rows transversely, preferably perpendicularly, to a main material conveying direction (see again the arrow on the left in Fig. 1). A key feature of the sieve according to the invention is that a safety zone 1.2, which leaves the sieve body surface 1.1 free, is provided between a hole edge 2.1 of the sieve hole 2 and the wear-resistant bead 3. As already explained at the outset, this feature ensures, on the one hand, that the edges of the sieve holes 2 are very well protected against damage. On the other hand, the safety zone 1.2 ensures that the edges of the sieve holes 2, which define the exact size, are not impaired or damaged when the wear-resistant bead 3 is applied. As can be seen from the figures, a wear-resistant bead 3 is preferably arranged on opposite sides of a sieve hole 2. In this context, it is also preferably provided that the sieve holes 2 and the wear-resistant bead 3 are arranged alternately relative to each other in a direction transverse, preferably perpendicular, to a main material conveying direction. In more detail, it is particularly preferred that the safety zone 1.2 between the hole edge 2.1 and the wear-resistant bead 3 has a dimension of at least 0.5 mm, preferably at least 1 mm, and most preferably at least 2 mm. Depending on the material being screened, the dimension can also be larger, preferably at least 3 mm, 4 mm, or even 5 mm. To further improve wear protection, it is also preferably provided that the wear protection bead 3 or wear protection bead 3 is or are made of a material that is at least as hard, preferably harder, than the sieve body 1. For particularly simple production of the sieve according to the invention, it is further preferably provided that the wear protection bead 3 is attached to the sieve body 1 by joining, in particular by welding. With regard to optimal dimensioning, it is further preferably provided that the extension of the wear protection beads 3 in a perpendicular direction to the surface of the sieve body 1.1 is at most one eighth, preferably at most one quarter, particularly preferably at most half, as high as the thickness of the sieve body 1 also extending perpendicular to the surface of the sieve body 1.1. Particularly in cases where several sieves are arranged consecutively, often with a step between them from which the material to be sieved falls onto the subsequent sieve, it is especially preferred that the wear-resistant ridges 3, viewed in the main material conveying direction, are optionally higher and / or harder at the beginning of the sieve body 1 than further along the sieve body 1. This feature ensures particularly good protection of the sieve in a particularly stressed area. As can be seen from Fig. 1, it is further preferably provided that at least one wear protection bead 3, oriented towards a main material conveying direction (again arrow to the left), is shorter than, preferably at most half as long as, an adjacent sieve hole 2. Alternatively, it may also be preferable, which is readily conceivable but not explicitly shown in the figures, that at least one wear-resistant bead 3 extends over a length of several sieve holes 2. Reference symbol list 1 Sieve body 1.1 Sieve body surface 1.2 Safety area 2 Sieve hole 2.1 Hole edge 3 Wear protection bead QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature DE 25 32 379 A1

[0002] DE 197 19 482 C2

[0003] DE 2 318 601 C3

[0010]

Claims

Sieve comprising a sieve body (1), a plurality of sieve holes (2) penetrating the sieve body (1) and opening onto a sieve body surface (1.1) of the sieve body (1), and wear protection beads (3) associated with the sieve holes (2) and arranged on the sieve body surface (1.1), characterized in that a safety area (1.2) leaving the sieve body surface (1.1) free is provided between a hole edge (2.1) of the sieve hole (2) and the wear protection bead (3). Sieve according to claim 1, characterized in that the safety area (1.2) between the hole edge (2.1) and the wear protection bead (3) has an extent of at least 0.5 mm. Sieve according to claim 1 or 2, characterized in that the wear protection bead (3) is formed from a material of at least the same hardness as the sieve body (1). Sieve according to one of claims 1 to 3, characterized in that the wear protection bead (3) is formed by joining it to the sieve body (1). Sieve according to one of claims 1 to 4, characterized in that the extension of the wear protection beads (3) in a perpendicular direction to the sieve body surface (1.1) is at most one eighth as high as the thickness of the sieve body (1) also extending perpendicular to the sieve body surface (1.1). Sieve according to one of claims 1 to 5, characterized in that the wear protection ridges (3) are optionally higher and / or harder at the beginning of the sieve body (1) when viewed in the main material conveying direction than in the further course of the sieve body (1). Sieve according to one of claims 1 to 6, characterized in that at least one wear protection bead (3) extends over a length of several sieve holes (2). Sieve according to one of claims 1 to 7, characterized in that at least one wear protection bead (3) is shorter than an adjacent sieve hole (2) when viewed from a main material conveying direction. Sieve according to one of claims 1 to 8, characterized in that the sieve holes (2) and the wear protection ridges (3) are arranged alternately to each other in a direction perpendicular to a main material conveying direction. Sieve according to one of claims 1 to 9, characterized in that the sieve holes (2) have a cross-section that increases in size from the surface of the sieve body (1.1) into the sieve body (1).

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