RU2428264C2 - Flexible screening mat for fine fractions - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to screen for sieving coarse and fine fractions. Screen comprises first moving system with first crosswise beams, second moving system with second crosswise beams. Note here that first and second moving systems displace relative to each other. Besides, there is at least one synthetic screening mat jointed with first and second crosswise beams to allow compression and expansion of screening mats. Jointing element features higher elongation at rupture to prevent mat tear and seizure of material particles in mat cells. Said jointing element represents plastic clamping element that may be fixed on appropriate first crosswise beams and/or appropriate second crosswise beam, wherein mat is poured. Said jointing element represents plastic clamping element that may be fixed on appropriate first crosswise beams and/or appropriate second crosswise beam, wherein mat is poured. Mat cell size makes less than 2 mm.

EFFECT: higher efficiency of screening, ruling out mat rupture.

15 cl, 11 dwg

Description

Field of Invention

The invention relates to a screen with a wavy tension of a screening surface including a first movable system comprising a first transverse beam and a second movable system comprising a second transverse beam, the first and second systems being movably relative to each other, and at least one a sieve mat made of synthetic fabric that is fixed both to the corresponding first transverse beam and to the corresponding second transverse beam to achieve alternating compression and stretching of the screening mats, according to the restrictive part of claim 1 of the formula, as well as to the screening unit with a wavy tension of the screening surface containing the screening mat and intended to be fixed on one transverse beam of one movable screening system located in the edge zone of the clamping element, according to the restrictive part of paragraph 12 of the formula.

Screens with wavy tension on the screening surface are already known. They are used for screening large and small fractions and are characterized by compression and stretching of screening mats, which significantly reduces the formation of stuck particles compared to screens with fixed screening mats.

State of the art

Traditional screening mats are made in most cases from polyurethane, and the holes are made by punching. These traditionally made screening mats are durable and have a long load capacity, and both of these criteria are crucial for use in such screens, since alternating stretching and compression of the screening mats causes alternating loads that adversely affect the durability of the materials used.

Hole punching is, however, a time-consuming and expensive process associated with the long production time of the sifting mat. In addition, the diameter of the holes during punching cannot be arbitrarily reduced, which is due to the technology, or, in other words, there is a limit to the size of the holes, from which their punching is no longer possible both from the point of view of the technology itself and from the point of view of profitability. In practice, this limit value is approximately 1 mm for square holes and approximately 0.4 × 4 mm for slit-like holes.

However, practice shows that there is a sufficient need for screens for extremely finely sifted screening material, and so far no adequate solutions have been found in the area of screens with wavy tension of the screening surface due to the mentioned technological difficulties to adequately satisfy this need.

US 4,430,211 discloses a wavy pulling screen containing two movable systems of transverse beams, the first and second systems being movably relative to each other, and plastic screening mats are provided that are mounted on the corresponding first transverse beam and on the corresponding second transverse beam for Achieve alternating compression and stretching of screening mats. At the same time, the screening mats are fixed on the transverse beams with traditional clamping bars.

From other areas of screening, but not from the field of such screens, it is known to use screening mats made of wire mesh. Such a screening mat is described, for example, in DE 3811641 A1. These sifting mats provide, however, the manufacture of especially small holes, but their use in a screen with wavy tension is not possible, which is due to the material, since the alternating compression and stretching of the screening mats arising in such a screen are impossible in the case of screening mats from wire mesh or in a short time lead to their rupture.

In the case of particularly finely sifted screening material from other screening areas, it is known to use screening mats from synthetic fabric, for example polyamide fabric. Due to their fabrication, in contrast to polyurethane screening mats with punched holes, these screening mats make it possible for them to be especially finely meshed, which also results in a significantly larger open screening surface, which also leads to a decrease in the design value of equipped with such screening mats screening.

The problem of sifting mats made of synthetic fabric for fine fractions, however, is their insufficient tensile elongation for use in screens with wavy tension, so that such synthetic fabrics have not yet been used in such screens. As already mentioned, in order to prevent particles from getting stuck in them, the screening mats are alternately compressed and stretched, and each time the process of stretching follows the compression process, the screening mats are excessively stretched so that the whip effect resulting from this almost completely prevents particles from getting stuck and releases blocked holes.

In the case of traditional polyurethane screening mats used in such screens, this whip effect is not a problem since the polyurethane has a tensile elongation of about 400%. The term "tensile elongation" is a term used for elastomers, which for other materials sounds like "relative elongation" and indicates how much percent the material can stretch before it breaks. Due to the high tensile elongation, the polyurethane screening mats were immune to the whip effect that occurs when using them in the described screens.

The synthetic fabric used as sifting mats in other screens, however, has a tensile elongation of only 30-40%, which is why when using such sifting mats in the described screens and with their excessive stretching or with the whip effect, they would burst.

However, the rejection of the whip effect would drastically reduce the screening performance due to increased particle jamming and would require downtime during which stuck particles would have to be manually removed from the mats.

SUMMARY OF THE INVENTION

Therefore, the objective of the present invention is to eliminate this drawback and improve the known screens with a wavy tension of the screening surface so that they can also be used for extremely finely sifted material.

Another objective of the invention is the adaptation of screens with a wavy tension of the screening surface so as to make it possible to use screening mats made of plastic for small fractions without breaking these mats or without reducing their resistance to values that are unacceptable in practice.

According to the invention this is achieved by the distinguishing features of claim 1 of the formula.

Moreover, it is provided that in the screens known per se with undulating tension of the screening surface including a first movable system comprising first transverse beams and a second movable system containing second transverse beams, the first and second systems being movably with respect to each other, and at least one sieving mat made of synthetic fabric is provided, which is fixed both to the corresponding first transverse beam and to the corresponding second transverse beam to achieve alternating compression and stretching of the screening mats, the screening mat is made in the form of a screening mat for fine fractions and is connected to the corresponding first transverse beam and / or to the corresponding second transverse beam through at least one corresponding connecting element, which compared to the manufactured made of synthetic fabric, the mat has a greater tensile elongation.

Due to the aforementioned lower tensile elongation of the synthetic fabric compared to polyurethane screening mats with punched holes due to the location of one or more elastic connecting elements between the mat and the first and second movable systems or between the mat and the corresponding first and second transverse beams, the whip effect is suppressed, which, however, Does not interfere with its hole-cleaning action. In this case, it is important to precisely match the material of the connecting element or the tensile extension of its material (for example, due to the elastic modulus). It should be chosen so that the sharply arising load during alternate compression and stretching of the mats is not extinguished too much and so that this does not prevent the whip effect from occurring, as a result of which cleaning from stuck particles will not occur. On the other hand, the material should be selected so that the mats are not too wide.

According to a preferred embodiment of the invention according to claim 2, it is provided that the at least one connecting element is a spring element, wherein, for example, a conventional coil spring could be used, which secures the mat on a first movable system, for example, a screen box, and on a second movable system, for example a swinging frame, by means of corresponding transverse beams.

According to another preferred embodiment of the invention according to claim 3, it is provided that the connecting element is a plastic clamping element which is adapted to be fixed to the corresponding first transverse beam and / or the corresponding second transverse beam and into which the mat is poured. This option is particularly durable.

In another preferred embodiment of the invention according to claim 4, it is provided that the connecting element is a plastic liner embedded in a seat secured to a corresponding first transverse beam and / or to a corresponding second transverse beam of the clamping element. This plastic insert is also filled with a mat. In this case, the clamping element may well be made of a harder material and not have the use of tensile elongation or elasticity required for this case, since the quenching effect of the whip element in this embodiment is a plastic insert made in the clamping element into which the mat is poured. The fixing of the mat in a plastic insert can be carried out, for example, by pouring the mat in plastic or, for example, by vulcanization or gluing.

According to the distinguishing features of Clause 5, the slots are slotted, which makes it possible to especially fasten the mat in the nests or the plastic inserts inside them.

According to another preferred embodiment of the invention according to claim 6, it is provided that the connecting element and mat form a replaceable assembly. Due to this, it is already possible to make such a unit in advance and fix it in place on a screen, for example, clamp it. In particular, in the case of the clamping element provided, it can already have a shape corresponding to the possibilities of fastening on the screen, in particular the transverse beams, so that a quick and yet reliable fastening of the assembly on the screen is possible.

According to another preferred embodiment of the invention according to claim 7, it is provided that the connecting element is located on the corresponding first transverse beam and / or on the corresponding second transverse beam, mainly a separate elastic element. In this case, the synthetic fabric mat can be fixed directly to the corresponding first transverse beam and / or to the corresponding second transverse beam.

In this case, according to claim 8, fastening means are provided that connect the elastic element, on the one hand, to the mat and, on the other hand, to the corresponding first transverse beam and / or to the corresponding second transverse beam.

According to another preferred embodiment of claim 9, it is provided that at least one of both warp and weft thread groups forming a mat of synthetic fabric is located obliquely to the transverse beams, i.e. neither parallel nor at right angles to them. Thus, it is achieved that the synthetic fabric has in the directions of compression and tension a higher tensile elongation or elasticity than would be possible without oblique arrangement. Due to this, the connecting element can be made a little more rigid without the risk of tearing the mat of synthetic fabric.

In one particular embodiment of FIG. 10, it is provided that the synthetic fabric mat serves as a connecting element, and the necessary tensile elongation for using the mat in screens with wavy tension is ensured by an appropriate arrangement of the warp and the weft obliquely with respect to the transverse beams. In this case, an additional connecting element is no longer required to fix the mat on the transverse beams, and mats made of synthetic fabric can be mounted on them in the traditional way.

According to the distinguishing features of clause 11, the size of the square holes of the synthetic fabric mats is less than 2 mm × 2 mm, and the rectangular ones - 2 mm × X mm (X = more than 2 mm).

Sections 12-15 relate to a screening unit with a wavy tension, comprising a screening mat and designed to be fixed on one transverse beam of one movable screening system, a clamping element located in the edge zone, the screening surface being made in the form of a screening mat made of synthetic fabric for fine fractions, and the clamping element contains a connecting element having a greater tensile elongation compared to the mat. The location of the connecting element serving as a damping effect of the whip of the connecting element directly on the screening mat made of synthetic fabric provides the use of such mats with a correspondingly small size of the holes in the screens with wavy tension, the connecting element and the mat forming an interchangeable unit, which facilitates the replacement of the entire unit in the screen.

According to one preferred embodiment of claim 13, the clamping element itself, which creates the connection between the mat and the respective transverse beams, is made as a connecting element with a large elongation.

According to another preferred embodiment of claim 14, the clamping element has a predominantly slit-like socket with a plastic insert that serves as a connecting element and to which the mat is connected, for example by pouring.

Below the invention is described in more detail on the example of its implementation, shown in the drawings, which represent:

- figure 1: axonometric view of the screen with a wavy tension of the screening surface;

- figure 2: a schematic side view consisting of a screening mat and a connecting element of the node with the spring element;

- figure 3: schematic side view consisting of a screening mat and a connecting element of the node with a clamping element and a plastic insert;

- figure 4: schematic side view consisting of a sifting mat and the connecting element of the node with the clamping element without a plastic insert;

- figure 5: schematic side view of the node in the state fixed on the transverse beams;

- Fig.6: top view of the node;

- Fig.7: an alternative embodiment of the clamping element;

- Fig: schematic side view of the node in a state fixed on the transverse beams;

- Fig.9: a schematic side view of a screening mat in a state fixed on one transverse beam with a separate connecting element;

- figure 10: top view of the site with oblique duck and base;

- 11: a top view of a node with an oblique weft and a base.

Ways to implement the invention

Figure 1 in the form of a preferred design shows the screen 1 with a wavy tension of the screening surface, containing the box 3 with the side walls 3A, 3b as the first movable system, supported by shock absorbers 15 on a fixed base, and driving the box 3 into oscillation drive 16, which can be made, for example, in the form of a single or double unbalanced drive. The side walls 3a, 3b are interconnected by several transverse beams 2 of the box, forming the first transverse beams parallel to each other.

A second movable system is made on the box 3, in this case in the form of a swinging frame, containing push rods 17 mounted on the side walls 3a, 3b or on the slats 18 located on them. The push rods 17 are installed by means of elastic elements, for example rubber blocks or spring elements (not shown), so that the main vibration of the duct 3 causes further vibration of the swinging frame.

The push rods 17 are interconnected by means of the transverse beams 4 of the swinging frame, forming transverse beams parallel to each other and to the transverse beams 2.

The screening surfaces are formed by separate screening mats 5 arranged alternately on the transverse beam 4 of the swinging frame and the transverse beam 2 of the box.

The principle of operation of the screen is as follows. By means of the duct 3, driven by the drive 16, made in the form of an unbalanced drive, the swinging frame is also driven. Due to the elastic installation of the pushing rods 17 of the swinging frame on the box 3, its oscillation occurs, offset from the main vibration of the box 3. Due to the alternating fastening of the screening mats 5 on the box 3 or on its transverse beams 2 and the transverse beams 4 of the swinging frame, the mats 5 are alternately compressed and stretch or excessively stretch, as a result of which not only the screening of the sifted material occurs, but their clogging by stuck particles is also prevented. This, in turn, causes an optimal sieving effect.

In this example, a screen with a single screening plane is considered. It is understood that several sifting planes can be arranged one above the other, which is also common in screens with wavy tension on the sieving surfaces. In this case, either several pushing rods 17 are elastically mounted on the box 3, or several transverse beams 4 of the swinging frame passing in different planes on one pushing rod 17.

This oscillating system may also have a banana design with a continuously decreasing tilt of the deck.

So that such screens can be used for screening fine fractions, according to the invention, it is provided that at least one of the screening mats 5 is made in the form of a screening mat for fine fractions of synthetic fabric, which is connected to the corresponding transverse beam 4 of the swinging frame and / or with the corresponding transverse beam 2 of the box by means of at least one connecting element 6, 7, 8, having a greater tensile elongation than the mat 5 made of synthetic fabric.

In this case, different execution principles should be distinguished, namely, on the one hand, the principle in which the mat forms a removable assembly with the connecting element. In this case, the connecting element and the mat are interconnected mainly in one piece.

The second principle provides that the quenching effect of the whip connecting element is an element located on the element of the corresponding transverse beam 4 of the swing frame and / or the corresponding transverse beam 2 of the box, the tensile elongation of which according to the invention is higher than the mat.

Figure 2-4 shows examples in which the first principle is implemented.

Figure 2 schematically shows a mat 5, which is made in the form of a spring element 6 of the connecting element is connected to the clamping element 12 known per se, which does not have any additional requirements, except that it must be fixed on the transverse beam 2 , 4 of one of both mobile systems.

Figure 3 shows a node with a mat 5 and a clamping element 10 having a helical socket 11. In the socket 11 there is a connecting element made in the form of a plastic insert 7, which is poured into it or otherwise fixed in it. The ends of the synthetic mat fabric are embedded in a plastic insert 7. In this case, the clamping element 10 can also be made of a material with a lower tensile elongation, since there is a plastic insert 7 as a damping elastic element with a corresponding tensile elongation, which prevents the tearing of the synthetic mat fabric when it occurs whip effect.

Figure 4 shows another variant of the first exemplary embodiment. Moreover, made in the form of a clamping element 8, the connecting element is cast directly with the mat 5 and forms a connecting element. In this embodiment, it is therefore required that the clamping element has a desired tensile elongation, which according to the invention should be higher than the tensile elongation of the synthetic fabric forming mat 5.

In Fig.2-4, the clamping elements 8, 10, 12 have a special shape, which ensures their reliable and quick clamping on the transverse beams 2 of the box and the transverse beams 4 of the swinging frame, as shown in Fig.5. The clamping elements 8, 10, 12 have for this purpose a corresponding recess 19, with which they are put on the transverse beams 2 of the box and the transverse beams 4 of the swinging frame. To strengthen the fastening of the clamping elements 8, 10, 12 on the transverse beams 2 of the box and the transverse beams 4 of the swinging frame is provided / provided, for example, a pin 25 or a strap 25, so that the clamping elements 8, 10, 12 are fixed on the transverse beams 2 of the box and transverse beams 4 swinging frame without bias.

In the case of clamping elements in Fig.2-4 we are talking about a possible embodiment. Of course, other options are possible, providing reliable fastening of the nodes of the screening mats on the transverse beams 2 of the box and the transverse beams 4 of the swinging frame.

Such an alternative embodiment of the clamping element is shown, for example, in Fig.7. The assembly consists of a mat 5 and a clamping element 20, the latter having a different shape than in FIGS. 3 and 4, however, it is identical in construction, i.e. either has a socket with a plastic insert 7 into which the connecting element is poured, or itself forms the connecting element and is made accordingly elastic. However, in contrast to the clamping elements 8, 10 in FIGS. 2 and 3, the clamping element 20 is flat. In this case, fixing means 14, for example a screw, as shown in Fig. 8, are used to fix on the crossbeams 2 of the box and the transverse beams 4 of the swinging frame.

In Fig.6, when viewed from above, a mat 5 of synthetic fabric is shown, as shown in Figs. 2-5 and 7, 8. A clamping element 8, 10, by means of which the beam is fixed on the transverse beams 2 of the box and the transverse beams 4 of the swinging frame passes in the longitudinal direction of the mat along its edge zone.

Figure 9 shows a variant of the second principle of execution. In this case, the connecting element 13 is predominantly in the form of a separate element fixed on the transverse beam 2 of the box and the transverse beam 4 of the swinging frame with fixing means 14, for example a screw. The fastening means 14 serves simultaneously to directly fix the mat 5, which in this case does not have to contain a clamping element, on the cross beam 2 of the box and the transverse beam 4 of the swing frame by clamping between the clamping element 21 and the connecting element 13. In this way, a very elastic connection of a synthetic fabric mat with a transverse beam 2 of the box and a transverse beam 4 of the swinging frame.

10 and 11, when viewed from above, a mat 5 of synthetic fabric is shown in accordance with another preferred embodiment of the invention. To navigate, the transverse beams 2 of the box and the transverse beams 4 of the swinging frame are shown schematically. At the same time, the group of fabric threads forming the base 23 in FIG. 10 is located not parallel to the sieving direction 24, but obliquely.

In another embodiment of FIG. 11, a group of threads forming ducks 22 is also located obliquely to the transverse beams 2 of the box and the transverse beams 4 of the swinging frame. Due to the oblique arrangement in the direction of sieving 24, a higher elasticity of the synthetic fabric is achieved, and thereby breaking elongation is increased. With a sufficient arrangement of obliquely groups of threads, the clamping elements 8, 10 indicated in FIGS. 10, 11 are no longer required, so that in this special case the synthetic fabric itself forms a connecting element. In this case, an additional elastic connecting element is no longer required to connect the synthetic fabric mat with the transverse beams 2 of the box and the transverse beams 4 of the swing frame.

However, a combination of such mats with an oblique weft 22 and / or an oblique base 23 with clamping elements 8, 10, as in FIGS. 3, 4, or with spring elements 6, as in FIG. 2, may be provided.

Claims (15)

1. A screen with a wavy tension of the screening surface, comprising a first movable system comprising a first transverse beam (2) and a second movable system comprising a second transverse beam (4), the first and second systems being movably relative to each other, and is provided, at least one sieve mat made of synthetic fabric (5), which is fixed both on the corresponding first transverse beam and on the corresponding second transverse beam to achieve alternating compression and stretching I sifting mats (5), characterized in that the sifting mat (5) is made in the form of a sifting mat for fine fractions and connected to the corresponding first transverse beam (2) and / or to the corresponding second transverse beam (4) by at least , one corresponding connecting element (6, 7, 8), which, compared with the mat made of synthetic fabric (5), has a greater tensile elongation. 2. The screen according to claim 1, characterized in that the connecting element is a spring element (6). 3. The screen according to claim 1, characterized in that the connecting element is a clamping element (8) made of plastic, which is made with the possibility of fixing on the corresponding first transverse beam (4) and / or the corresponding second transverse beam (2) and in which flooded mat (5). 4. A screen according to claim 1, characterized in that the connecting element is a plastic insert (1) embedded in a socket (11) fixed on the corresponding first transverse beam (2) and / or on the corresponding second transverse beam (4) of the clamping element (10) 7) into which the mat is poured (5). 5. The screen according to claim 4, characterized in that the nest (11) is slotted. 6. The screen according to claim 1, characterized in that the connecting element (6, 7, 8) and the mat form a removable assembly. 7. The screen according to claim 1, characterized in that the connecting element is located on the corresponding second transverse beam (4) and / or on the corresponding first transverse beam (2), mainly a separate element (13). 8. A screen according to claim 7, characterized in that fastening means (14) are provided connecting the element (13), on the one hand, with the mat (5), and, on the other hand, with the corresponding first transverse beam (2) and / or with a corresponding second crossbeam (4). 9. The screen according to claim 1, characterized in that at least one of the two groups of threads consisting of a warp (23) and a weft (22) of threads forming a synthetic fabric mat (5) is located obliquely to the transverse beams or direction (24) transportation. 10. The screen according to claim 1, characterized in that the connecting element is part of the mat (5), and at least one of both groups of threads consisting of a warp (23) and a weft (22) of a synthetic fabric forming a mat (5) located obliquely to the transverse beams (2, 4). 11. The screen according to claim 1, characterized in that the cell size of the mats (5) is less than 2 mm 12. Assembly for a screen (1) with a wavy tension of the screening surface, containing a screening mat made of synthetic fabric (5) and designed to be fixed on the transverse beam (2) of the mobile screening system (1) located in the edge zone of the clamping element (8, 10), characterized in that the screening surface is made in the form of a screening mat made of synthetic fabric (5) for fine fractions, while the clamping element (8, 10) contains a connecting element or is made in the form of a connecting element having greater tensile elongation compared to mat (5). 13. The node according to item 12, characterized in that the clamping element (8) is made in the form of a connecting element. 14. The assembly according to claim 12, characterized in that the clamping element (10) has a predominantly slit-like socket (11) with a plastic insert (7) as the connecting element to which the mat (5) is connected is predominantly poured into it. 15. The node according to item 12-14, characterized in that the size of the holes of the mats (5) is less than 2 mm

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