DE4210770A1 - Sieving machine with shallow V=section screen - giving reduced tendency for overloading - Google Patents

Abstract

Sieving apparatus having at least one sieve unit possessing a swinging frame, a sieve screen carried on the frame, and as necessary a collector unit for the under-size, and where the swinging frame is elastically mounted and able to be caused to swing by an oscillating device, with the novel features that the sieve screen is inclined from its centre outwards, with an opening for the over-size at the deepest point, and includes a discharge device for removing the oversize. USE/ADVANTAGE - Compact sieving machine with reduced tendency for screen to become overloaded by the feedstream.

Description

The invention relates to a screening device with at least one egg ner a swing frame, one carried by the swing frame Sieve bottom and possibly one essentially below the Siebbo dens arranged collecting device for the undersize send screening machine, the swing frame mounted elastically and vibratable by a vibrating device is.

Screening devices of the type in question have been around for years known from practice. Basically, these are Devices for separation from solid-liquid mixtures or for separating granular substances according to grain sizes, whereby here too Liquids, for example water, can be added. The actual work surface of the device in question gene, the so-called sieve plate, z. B. from pinhole with punched, drilled or more recently also by laser provided sieve openings of certain width, from so-called Sieve wire cloth, d. H. from intersecting metal or art fabric wires, or from corrugated longitudinal wires with in certain Distances woven in cross wires exist.

The simplest screening devices are the so-called litter sieves in which the material to be separated is usually against the inclined sieve plate is thrown. With technical Sieve devices are distinguished from fixed sieves, in which there are the material to be screened over the fixed sieve plate, e.g. B. over an inclined Sieve trough, moving and moving sieves, where the sieve area as a whole is moved. Such screening devices vibrating sieves, especially since the vibrating frame with the sieve bottom in Vibration is spent.

Screening devices of the type in question, d. H. so-called Vibrating screens have so far been used with the most varied  Types of vibrations applied or different Vibrations stimulated. So are as vibrating devices at for example eccentric vibrators, circular vibrators, linear vibrators and elliptical oscillators are used, the circular oscillators inso cause far more problems than the specific so generated Swinging movement for a targeted transport of the screened material predetermined direction leads. Linear oscillators and also ellipses become vibrating with screening devices of the one in question Kind basically preferred.

Sieving devices can be used in chemistry, for example Application in laboratories, but also in the field of "stones, Er the ", i.e. especially in the construction industry in the broadest sense, use. Wherever granular, granular or even pulverulent material should be separated into fractions, screening devices are required. By using sieve floors with different sieve grids can be fractions achieve different grain size.

Screening devices are particularly useful in the field of "stones, earth" with enormous sieving capacities required, especially here always large ones Amounts of screenings to be fractionated. In addition known Siebvor directions are usually equipped with sieve trays, which in the Linear conveyors are designed in the manner of a belt. At One end of the linear sieve bottom becomes too frak tioning screenings fed or placed on the sieve bottom brings and then along along the sieve bottom different. According to the sieve bottom grid, smaller grains fall, the so-called undersize, through the sieve bottom and the larger grains, the so-called Oberkorn, is due to the Vi bration of the swing frame or the sieve bottom and due to usually provided there, at least slight inclination of the Sieve bottom promoted over this.  

However, screening devices of the type discussed above are in practice, at least extremely problematic if they with large quantities of screenings. The area of the The sieve bottom is then no longer sufficient for the material to be sieved overall contacted the screen grid. Rather, they get high quantities of the screenings via the accumulation of the screenings across the sieve bottom without the sieve screen ever touching to have. As a result, particles become more normal should wisely fall through the sieve screen as undersize, conveyed over the sieve bottom and thus reach the Oversize, although it is actually the undersize in size are to be assigned. To compensate for the after occurring here in some cases, the length of the sieve plate has so far been used given screen section extended so that the upper layers of the screened material Coming into contact with the screen grid in the course of the screen length men. However, the more screenings at the feed station, i.e. H. to the one end of the sieve plate is placed on the sieve plate, the worse the sieving performance becomes even with long sieve gusts the. In other words, the sieve tray should be very large Amounts of material to be screened have an enormous length Completely impractical in view of the always limited space is.

The invention is therefore based on the object, a Siebvor direction of the type mentioned above and to further develop that the screening device with increased screening has only a small space requirement.

The screening device according to the invention solves the foregoing Task by the features of claim 1. After that the aforementioned sieve device designed so that the Sieve bottom is inclined towards the middle, at the deepest point has a passage for the oversize and that the  Passage a discharge device for removing the oversize connects.

According to the invention one has in the sense of a linear för their sieve trays completely removed. Rather, it is has been known that when sieving enormous amounts of screenings he required long sieve section can be compensated that the sieve bottom tilts towards the middle and at the deepest Place has a passage for the oversize, so that on Edge area abandoned screenings on all sides, d. H. on all sides of Edge area, is promoted towards the center. Hence the long distance required for linear conveyors trained sieve trays through a shortened route to Zen strum of the sieve bottom replaced, here an all-round Promotion of the screenings to the center is given. In the opposite to the sieve trays designed as linear conveyors here in the manner according to the invention the circumference of the sieve bottom Appropriate "widening" of the sieve bottom is achieved so that to achieve a sufficient sieving result for large Amounts of screenings require a much shorter screen section is. The scope given by the scope tapers Width of the sieve bottom towards the center considerably, however, increases towards the center also the amount of the material to be screened due to the already screened fraction from accordingly the transfer to be carried out in the center via the discharge device grain actually has a size that passes through the sieve grid of the sieve bottom could no longer get through.

By arranging for the middle passage closing discharge device for removing the oversize furthermore effectively avoided that the oversize grain again with the undersize through the mesh of the sieve bottom can mix. Here is an effective separation between Oversize and undersize achieved in the smallest space, with the  This space essentially by the area of the sieve plate give is.

With regard to the design of the sieve bottom, it is from before part of doing this round. Within the scope of such an issue the sieve bottom would be approximately conical towards the passage fall off, so that the screenings from the edge area evenly can get to the center.

The sieve bottom could also be angular. An inso the quadratic training would be a far preferred configuration dung of the sieve plate, the sieve plate then being advantageous could be composed of four surfaces and roughly could fall pyramid-shaped towards the passage. As part of such a configuration could the four surfaces of the sieve as an independent, held in a sieve tray frame and interchangeable sieve plate elements are designed. A such an arrangement would have the enormous advantage that in the case clogging or damage to one of the surfaces of the Sieve bottom easily and independently replaced could be without the other areas at the same time to have to Such a configuration certainly helps Operating costs of the screening device according to the invention significantly to reduce.

In a further advantageous manner, the sieve bottom could be a task device for the screenings. This task The screenings could essentially be set up on preference the entire edge area of the sieve falling towards the center Distribute the floor almost automatically, so that there is no distribution the screenings by hand or otherwise would be necessary. For this purpose, the feeding device could move from the edge area have falling distribution chute that circumferentially with at least slightly smaller dimensions adapted to the sieve bottom  would be so that the screenings over the edge of the distribution slide would be fed across the entire edge area of the sieve bottom. This could be the feeding device or the distribution slide fall from the center to the edge area and pyramid-shaped ge have stalt. Likewise, a conical shape would be the opening delivery device or the distribution slide possible. Essential in any case here is that the material to be screened from the feeding device is brought to the edge area of the sieve tray from there to the center of the sieve in the manner explained above to reach the bottom, only the so-called oversize falls through the passage in the center of the sieve plate, because the so-called undersize on the way to the center the mesh of the sieve bottom falls through.

In a further advantageous manner, the feed device one of the funnels upstream of the distribution slide, which the Feed material to the distribution chute approximately in the middle. From there the screenings come out due to the pyramidal or ke gel-shaped configuration of the distribution slide is approximately the same moderately distributed to the edge of the distribution slide and slips there over the edge of the distribution slide onto the Randbe realm of the sieve bottom. The screenings then migrate from there due to the vibration movement and inclination of the sieve bottom Middle.

If you want to form more than two factions, he points them out screening device according to the invention at least two screening machines each with a swing frame, a sieve plate and one in front switched feeder on. The discharge device of the first screening machine could for example become a second - downstream - sieving machine or to its task lead. This would mean that the fractional over grain, which goes through the central passage of the sieve bottom has failed, a subsequent, new screening process  would be fed. Likewise, the fall arrester of the he Most screening machine as feed device of a second screen be executed. In this case, that would be fractional Undersize, d. H. through the mesh of the sieve bottom arrived grain, be subjected to a further sieving process. Without further ado it is also possible to oversize as well to subject the undersize to another sieving process hen, then both the discharge device and the Thief floor as a quasi catch device a second or third Subordinate screening machine would be.

In the case of a configuration such that the catchment direction as a feed device of a second screening machine could be the distribution slide of the second Siebma machine directly under the sieve bottom of the first sieving machine be arranged so that here no further supply and correspond no additional feed device for the undersize is required.

As previously indicated, numerous could be used to attract Fractions several feeding devices and sieve trays arranged according to the modular principle - cascade-like will. The sieve trays and / or the discharge devices would then in each case a feed device with in turn reshaped Follow sieve trays. In this respect, cascading would be possible numerous other branches for generating any many fractions possible.

In material terms, it is advantageous if the Ver divider slide made of steel, preferably made of stainless steel represents is. In this respect, the use of stainless steel is special advantageous when the screenings to be fractionated are often moist or even rinsed with water, making corrosion effective is prevented. The distribution slide could also be made of art  fabric-coated steel, being made by choice a suitable plastic also the sliding of the screenings can be favored towards the edge.

The vibrating device acting on the vibrating frame can advantageously approximately in the middle under the sieve tray or be arranged in the passage, always being ensured here must be that there is a rigid connection to the swing frame is posed. As mentioned earlier, the Schwingein could direction as a linear oscillator known per se be.

Furthermore, it is particularly with regard to an optimal one Vibration of the entire screening device is advantageous if - in In case of cascading of several screening machines - each Sieve tray is assigned an independent vibrating device. This would have the enormous advantage that, depending on the Frak the vibrating devices for generating vibrations different frequencies applied separately can be. One or the other Schwingeinrich could also remain completely switched off while swinging Direction only a certain screening machine is activated.

The one to be vibrated by the vibrating device Swing frame requires sufficient freedom of movement Vibration. For this purpose, the swing frame is advantageous via elastic means on a rigid machine frame hangs. Tear-free can be used, for example, as elastic means Use the most rubber strands. With regard to a particularly one fold configuration, it is advantageous here, the elastic rule means as tension springs, so that the screening machine within the elasticity or spring stiffness of the springs would be suspended from the machine frame. Preferably here much tension springs provided on the edge of the Schwingrah  mens - in the case of a square design of the sieve size machine or the sieve bottom - at the corners of the sieve frame are directing.

There are now several ways to teach the present the present invention in an advantageous manner and white to train. On the one hand, this is based on the claim 1 subordinate claims, on the other hand to the subsequent Er purification of two embodiments of the invention based on the Reference drawing. In connection with the explanation of the preferred embodiments of the invention based on the Drawing are also generally preferred configurations and further training of teaching explained. In the drawing shows

Fig. 1 in a sectional view an execution of a screening device according to the invention, for example with two screens,

Fig. 2 in a plan view, schematically the screening machine from Fig. 1 with upstream feeder and

Fig. 3 is a schematic representation of a second exemplary embodiment of a Siebvorrich device according to the invention with several cascaded screening machines.

Fig. 1 shows a screening device having two screens 1. Each screening machine 1 has an oscillating frame 2 , a sieve plate 3 carried by the oscillating frame 2 and a collecting device 4 for the undersize grain arranged below the sieve plate 3 . The vibrating frame 2 is mounted elastically and can be brought into vibration by a vibrating device 5 .

According to the invention, the sieve bottom 3 is inclined towards the center and has a passage 6 for oversize particles at the deepest point. A discharge device 7 adjoins the passage 6 for removing the oversize.

In Fig. 2 it is indicated that the sieve bottom 3 is made square. The sieve bottom 3 is composed of four surfaces and falls pyramid-shaped towards the passage 6 .

A feeding device 8 for the material to be sieved is arranged upstream of the sieve tray 3 . The feed device 8 distributes the screenings over the entire edge region 9 of the screen bottom 3 falling towards the center. Fig. 1 also reveals that the task device 8 has a sloping to the edge region 10 distributor 11 cal. The distributor chute 11 is circumferentially adjusted with slightly smaller dimensions to the sieve plate 3, so that the screening material the entire Randbe 9 of the sieve can be supplied via the distributing chute 11 rich. 3 Fig. 2 shows that the feed device 8 drops from the center to the edge region 10 and has a pyramidal shape. A conical shape would also be conceivable.

Furthermore, FIG. 1 shows that the feed device 8 has a funnel 12 arranged upstream of the distribution slide 11 . The funnel 12 feeds the screened material to the distribution chute 11 approximately in the center.

In the embodiment shown in FIG. 1, the collecting device 4 is designed as a feeding device 8 of a second screening machine 1 . The distribution slide 11 of the second screening machine 1 is arranged directly under the sieve bottom 3 of the first screening machine 1 .

In the second embodiment shown in FIG. 3 egg ner sieving device according to the invention, a plurality of task devices 8 and sieve trays 3 , ie a plurality of sieving machines 1 , are arranged according to the modular principle - cascade-like. The sieve trays 3 and the discharge devices 7 are each followed by a feed device 8 with a sieve tray 3 connected downstream.

With regard to the generation of vibrations on the vibrating frame 2, it is also essential that the vibrating device 5 is arranged approximately centrally under the sieve bottom 3 or the passage 6 (cf. FIG. 1). Each sieve tray 3 is assigned an independent oscillating device 5 , the oscillating device being designed as a linear oscillator.

Finally, Fig. 1 clearly shows that the swing frame 2 is suspended on a machine frame 13 by elastic means. The elastic means are designed as tension springs 14 . Overall, four tension springs 14 are provided which are articulated on the edge region of the swing frame 2 at the corners thereof.

In conclusion, it should be noted that the core of the present Invention - design of the conveyor path of the sieve plate a sieve towards the center of the sieve bottom - also at otherwise implemented sieve devices can. The embodiment selected above as an example only Examples are intended to illustrate the teaching of the invention, however, in no way limit it to the exemplary embodiments.

Claims (23)

1. Screening device with at least one oscillating frame ( 2 ), a sieve plate ( 3 ) carried by the oscillating frame ( 2 ) and possibly an essentially below the sieve plate ( 3 ) on arranged collecting device ( 4 ) for the undersize sieve machine ( 1 ) , wherein the swing frame ( 2 ) elastically gela gert and can be brought into vibration by a vibrating device ( 5 ), characterized in that the sieve bottom ( 3 ) is inclined towards the center, at the deepest point a passage ( 6 ) for oversize and that the passage ( 6 ) is followed by a discharge device ( 7 ) for removing the oversize. 2. Screening device according to claim 1, characterized in that the screen bottom ( 3 ) is made approximately round. 3. Screening device according to claim 2, characterized in that the screen bottom ( 3 ) falls approximately conically towards the passage ( 6 ). 4. Screening device according to claim 1, characterized in that the screen bottom ( 3 ) is angular, preferably square, leads out. 5. A sieve device according to claim 4, characterized in that the sieve bottom ( 3 ) is preferably composed of four faces and is approximately pyramid-shaped towards the passage ( 6 ). 6. Screening device according to claim 5, characterized in that the four surfaces of the sieve plate ( 3 ) are designed as independent, in egg nem sieve plate frame and interchangeable Siebbo denelemente executed. 7. Screening device according to one of claims 1 to 6, characterized in that the sieve bottom ( 3 ) is a feed device ( 8 ) upstream of the material to be screened and that the device device ( 8 ), the material to be screened essentially on the entire ge preferably edge area ( 9 ) of the sieve bottom ( 3 ) falling towards the center. 8. Screening device according to claim 7, characterized in that the feeding device ( 8 ) has a to the edge region ( 10 ) from falling distributor slide ( 11 ), the circumference with at least slightly smaller dimensions of the sieve bottom ( 3 ) is adapted so that the Material to be sieved can be fed to the entire edge region ( 9 ) of the sieve bottom ( 3 ) via the distributor slide ( 11 ). 9. Screening device according to claim 8, characterized in that the feeding device ( 8 ) drops from the center to the edge region ( 10 ) and has a pyramidal shape. 10. Screening device according to claim 8, characterized in that the feeding device ( 8 ) drops from the center to the edge region ( 10 ) and has a conical shape. 11. A screening apparatus according to any one of claims 8 to 10, characterized in that the feed device (8) has one of the Ver splitter chute (11) upstream hopper (12), which centrally feeds the screenings of the distributing chute (11) approximately. 12. Screening device according to one of claims 1 to 11, characterized in that the discharge device ( 7 ) leads to a second - downstream - screening machine ( 1 ) or to the object direction ( 8 ). 13. Screening device according to one of claims 1 to 11, characterized in that the collecting device ( 4 ) is designed as a task device ( 8 ) of a second screening machine ( 1 ). 14. Screening device according to claim 13, characterized in that the distributor slide ( 11 ) of the second screening machine ( 1 ) is arranged di rectly under the screen bottom ( 3 ) of the first screening machine ( 1 ). 15. Screening device according to one of claims 1 to 14, characterized in that a plurality of feeding devices ( 8 ) and sieve trays ( 3 ) can be arranged in any way according to the modular principle - cascade-like and that the sieve trays ( 3 ) and / or the discharge devices ( 7 ) a feed device ( 8 ) with a downstream sieve plate ( 3 ) can follow. 16. Screening device according to claim 8 and optionally one of claims 9 to 15, characterized in that the distributor slide ( 11 ) is made of steel, preferably of stainless steel. 17. Screening device according to claim 8 and optionally one of claims 9 to 15, characterized in that the distribution slide ( 11 ) is made of plastic-coated steel. 18. Screening device according to one of claims 1 to 17, characterized in that the oscillating device ( 5 ) is arranged approximately centrally under the sieve bottom ( 3 ) or the passage ( 6 ). 19. Screening device according to claim 12 or 13 and possibly one of claims 14 to 18, characterized in that each screen plate ( 3 ) is an independent vibrating device ( 5 ) is assigned. 20. Screening device according to one of claims 1 to 19, characterized in that the vibrating device ( 5 ) is designed as a Li nearschwinger. 21. Screening device according to one of claims 1 to 20, characterized in that the swing frame ( 2 ) is suspended via elastic means tel on a machine frame ( 13 ). 22. Screening device according to claim 21, characterized in that the elastic means are designed as tension springs ( 14 ). 23. Screening device according to claim 22, characterized in that preferably four tension springs ( 14 ) are provided which are articulated on the edge region of the oscillating frame ( 2 ), preferably at the corners.