DE2650617C2 - Method and device for cleaning and sorting grain, seeds or similar useful goods - Google Patents

Description

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The invention relates to a method for cleaning and sorting grain, seeds or the like Useful material in which the mixed material is sorted into two fractions by means of an air stream is, of which the first fraction almost the entire share of the useful good and the two> e fraction in the essentially contains the light impurities, and in which this first fraction is divided into two substreams is divided, of which the first substream is essentially good useful goods and the second substream Contains both good and weaker Nutigut.

The invention also relates to a device for cleaning and sorting grain, seeds or The same useful material with a wind readout device, which has a substantially horizontally arranged and a grate traversed by an air stream substantially perpendicularly from bottom to top, over the the feed material is passed away, a first containing almost the entire portion of the useful material Fraction falls through the grate or down behind it, with a separator that separates the first fraction, seen in the horizontal flow direction of the feed material, in a first, front and a second, rear partial flow divided, and with separate collecting devices for the two partial flows.

A method and a device of the type mentioned above are disclosed in DE-PS 11 67 635 Known The known device has in a housing a grate made of profile bars, which opposite the Horizontal is slightly inclined and the goods in a substantially horizontal movement of one Is fed from the end. The grate is penetrated from below by such a strong air current that only the heavy parts of the abandoned goods fall down through the profile bars of the grate, while lighter parts like light impurities and more or less light grains with the Airflow can be torn upwards. The fraction of the abandoned that falls through the grate Guts therefore contains the predominant portion of the useful good, with the good useful good parts, the relative are difficult to fall through the grate at the beginning, while the lighter, weaker useful parts first a piece of the air flow over the grate and only near its end downwards fall. Under the grate there are two separate collecting devices for the falling goods, the are separated from each other by means of an adjustable flap that the front of the flap through the grate Falling material forms a first partial flow, which falls into a different collecting device than the second, behind partial flow falling through the grate of the flap. The useful goods contained in the first partial flow are on average better than that of the second substream. However, it is not possible to adjust the flap so that the first Partial flow contains only good useful goods and the second partial flow contains only weaker useful goods Rather, weaker ones as well as good ones in the second partial flow will each other Good parts are located. Exact sorting is therefore not possible with the known device.

At another grain cleaning machine known from the patent proprietor's "Primus" brochure ne is the material in a similar way first on the horizontally arranged grate of a wind readout device abandoned, which is penetrated from bottom to top by a stream of air, so that lighter Cereal bodies and light contaminants are torn up with the airflow, while only the heavier parts of the abandoned goods, which include both useful goods and impurities, by the Rust falling down. However, there is no division of the fraction falling through below the grate made of the abandoned goods in different substreams. Rather, the failing faction will evenly distributed over two separate sieve arrangements, both from a so-called scroll sieve and a sand sieve. The scroll screens are designed so that the good and the weaker Useful goods including the smaller contaminants corresponding in size to the useful goods the sieves fall through while scrolls, which are gross debris such as thistles, large stones and the like, remain on the sieve surface and are discharged from here as waste. The sieves of the scroll Passing parts reach a sand sieve through which fine-grained impurities and possibly broken grains falls through, while the useful material remains and is led to a Nutzgutauslaß. With This known device can achieve the desired separation of the useful material into good and weaker ones Useful goods are not made.

From DE-OS 21 35 295 it is known, following a wind sifting, a first, the useful material

split the fraction containing into two equal partial flows and separate these sieve arrangements to feed. Both substreams have the same composition and are subjected to the same sieve treatment. The object of the invention is to provide a method and a device that can A very high hourly output, i.e. a large throughput of goods per unit of time, enable an optimal to sort out a high proportion of the good useful good contained in the abandoned good.

According to the invention, this object is achieved in a method of the type mentioned at the outset by that the second substream is subjected to a sorting sieve for the purpose of sorting into good and weaker useful goods and that then the good useful material sorted out by the sorting sieve with the first partial flow is reunited.

It is possible to obtain the reading obtained by the wind, which contains almost the entire portion of the useful material To divide fraction into two such substreams, of which the first, possibly in addition to impurities, contains almost only good useful material. This has the consequence that the second substream is essentially weaker useful good, but also has a not inconsiderable part of good useful good this proportion of good useful material is also obtained in the second partial flow, this second partial flow becomes one Sorting sieving for the purpose of separation into good and weaker useful goods. This sorting sieving can be carried out with a good efficiency and a high screening capacity, as in the context of Such cleaning and sorting devices are the usual size for the second partial flow, which is only a more or less large part of the first fraction makes up a relatively large sieve area Can be provided.

A device of the type mentioned at the beginning is suitable for carrying out this method characterized in that the separating device is arranged so that the first partial flow is essentially only good useful material and the second partial stream contains good and weaker useful material that a sorting sieve arrangement and one that connects the collecting device for the second partial flow to this sorting screen arrangement first channel are present, the sorting screen device from the second partial flow the good • Useful goods sorted out, and that a second and a third channel are present, which carry the sorted out good useful goods and lead the first partial flow to the same Nutzgutauslaß.

A good effect of the separating device can be achieved if it consists of a horizontal Direction of flow of the feed material is arranged behind the grate peeling plate, which is preferably has a shape corresponding to the curvature of the flow of material in this area, notwithstanding this advantageous shape Embodiment of the separating device, however, the peeling plate can in principle also under or be arranged between the grate. The exact position of the peeling plate depends on the strength of the air flow and possibly also on the composition of the abandoned good. The location of the peeling plate is therefore preferably adjustable.

As a rule, the abandoned goods will contain coarse and / or fine-grained impurities also have to be removed from the first partial flow before it is passed to the useful material outlet. to For this purpose, a first roll screen can be used to remove coarse contaminants and / or a Cleaning sieve to remove fine-grained impurities for the first partial flow can be provided are connected by a further, fourth channel to the collecting device for the first partial flow. Fine-grained impurities are automatically removed from the second substream during sorting sorted out, so that only a second scroll screen is additionally provided for the second partial flow must if corresponding impurities are to be sorted out. As a cleaning sieve for the first Partial flow does not carry out useful goods sorting, the cleaning sieve for the first partial flow with a greater screening capacity, d. H. with more gui task per Sieve area and time unit are operated as the sorting sieve arrangement for the second partial flow.

A third collecting device is preferably located below the sorting sieve arrangement, which collects the catches weaker useful material falling through and possibly fine-grained impurities, whereby these third collecting device is connected via a fifth channel to a second outlet through which this weaker useful goods as second choice material, e.g. B. as feed grain, can be removed.

The second fraction of the abandoned good, which is carried by the airflow of the wind reading alignment over the grate Is torn up, is primarily made up of light impurities such as dust, peel and broken peel and straw and, depending on the type of feed, more or less useful material together. So on the one hand that In this second fraction, if necessary, useful material still contained can be obtained, and thus for Another precleaning of the air flow is achieved, it is advantageous if that with the second fraction loaded air flow is directed or deflected into an expansion space, whereby its flow velocity slowed down and the heavier part of the light impurities as well as possibly Set down useful goods on the floor of the expansion space. Then through an air outlet in the expansion space the air with the remaining impurities is sucked off and fed to an air purification device An opening can be arranged at the bottom of the expansion space, which has a sixth channel is connected to a third scroll screen. The scrolls remain on this third scroll screen back, while useful material and smaller impurities pass through the sieve to a subsequent sorting sieve reach. This sorting sieve is designed similarly to the sieve of the sorting sieve order already mentioned and lets fine-grained impurities and weaker goods fall through, while good in size Useful material remains on this sorting sieve. A fourth collecting device under the sorting sieve catches this falling goods and also leads it to the second outlet, d. H. to the outlet for material second Choice

The useful material of good size, which has passed through the third scroll sieve on the sorting sieve remains, however, can either go to the useful material outlet, to the second outlet or back to the material inlet the device are performed. The decision as to which of these alternatives is possible can be made in the Individual cases can be made dependent on an examination of this good. '

It is advantageous if the first, second and third Scroll sieve, i.e. the scroll sieve for the first one Partial flow, that for the second partial flow and that for the

Deposits from the expansion space are arranged side by side in the same plane. This has, among other things, the Advantage that the Schroller remaining on the three scroll sieves. over a common channel can be discharged. For example, the three scroll screens can be in one opposite the horizontal be arranged slightly inclined plane, so that the scrolls due to gravity, supported by the screen vibrations, migrate to an edge of the scroll screen arrangement and there fall into the discharge channel. Another advantage of the arrangement of the three scroll screens side by side in one plane is that skipped parts are caught by the respective neighboring roller screen.

It has already been stated that the sorting sieve arrangement for the second partial flow should be as large as possible Should have sieve surface. This can be done with optimal use of the in a cleaning and sorting device of the usual dimensions available space can advantageously be achieved by that a number of individual sorting sieves, depending on the given height, lie one below the other in different levels are arranged, wherein a distribution device ensures that the in the second Scroll screen pre-cleaned second partial flow evenly on the sorting screens of the Sorting screen assembly is distributed.

The air extracted from the expansion space is usually heavily loaded with light impurities, in particular dust, straw and trash and the like be enriched so that this air is advantageously cleaned before it is returned to the wind readout device in a circuit will.

The invention is described below using an exemplary embodiment with reference to the drawings explained in more detail. It shows

F i g. 1 shows a schematic overview of the usual composition of a cereal and Contamination of existing property, its grain or nulzgulanleil sorted and its contamination should have been removed,

2 shows a schematic sectional side view of a device according to the invention,

F i g. 3 is an enlarged illustration of part of the sorting arrangement and the cleaning sieve of FIG. 2, and

4 shows a partial longitudinal section along the line IV-IV in FIG. 3 to explain the distribution facility.

Fig. 1 shows an overview of the form in which Grain, which is to serve here as an example of the useful goods to be cleaned and sorted, usually from the harvest is delivered. The grain is part of a mixed product, the grain grains are good and weaker The mix also contains so-called rolls, ie. Impurities that are larger than the good grains, and be equally heavy, lighter or heavier than these can. As further impurities are grains of sand available that are smaller than the grains and of different weights. Finally are still Light parts such as straw, dust etc. are not present are usable. Only part of this mix can therefore be processed as cleaned grain are fed. The task of the cleaning and sorting devices is to remove this grain portion Weed out and of the impurities too

to free.

To carry out this work, the device according to the invention provides a very specific combination of wind selection and screening. Fig. 2 shows schematically this device in a sectional side view. The housing of the device consists of two parts 1 and 2. In the housing part 1 are the Goods inlet 3 as well as an air inlet 4 and an air outlet 5. The goods delivered pass through the goods inlet 3 via a feed shaft 6 to the wind readout device. The feed shaft 6 ensures a uniform Distribution of the material task over the length of the device. The wind readout device consists of primarily from the grate 7, which can consist of several pivotably arranged profile bars. The grate 7 is penetrated from bottom to top by an air stream, which is indicated by the arrow 8 and comes from a fan 9 through the air inlet 4 into the housing part 1. To the Wind reading device also includes a guide surface 10, which is measured by the feed shaft 6 Mixture due to the action of gravity from an essentially vertical movement into an im A substantial horizontal movement over the grate 7 deflects guide or deflection surfaces 12, 13 and 14 the wind readout device are used to direct the resulting currents into suitable paths. These guide or deflection surfaces can be used to adapt to special compositions of the material to be mixed be adjustable.

When the mix leaves the guide surface 10 in a more or less horizontal direction, depending on the set inclination of this guide surface, it comes under the influence of the air flow 8. The heavy parts of the mix fall earlier, depending on their weight and the strength of the air flow or later down. In contrast, the lighter components of the mix are carried away by the air flow and lifted over the grate 7. The part of the mixed material that falls down by itself or after it hits one of the guide or deflection surfaces 12 or 13 is referred to as the first fraction, which is indicated by the arrow A in FIG. 1 is indicated. The remaining part, carried along with the air flow, is then the second fraction, which corresponds to arrow B.

The constituents contained in fractions A and B are shown in FIG. 1. Then fraction A comprises heavy rolls, good grain, weaker grain and sand. Fraction B contains easy steps, possibly a small proportion of good grain as well as weaker grain and non-usable light parts.

A peeling plate 15 arranged behind the grate 7 (which does not necessarily have to be a metal plate) divides the falling fraction A into two partial flows I and II. The position of the peeling plate 15 is chosen so that the partial flow I, as can be seen from Fig. 1, contains only good grain apart from impurities curved, ie concave as seen from the input end of the grate. The peeling plate 15, which is arranged approximately at the level of the grate 7, protrudes above and below the plane of the grate. Since there is no sharp separation between good and weaker with the wind readout device

Grain, this position of the peeling plate 15 necessarily leads to the fact that the partial flow II except Includes impurities in both good and weaker grain. The partial flows I and II are under the wind readout device collected separately and treated further.

The air flow entraining the second fraction B is with the help of the guide or deflection surfaces 12 and 14 in an expansion space. 16 guided within the first housing part. In the expansion space 16, the flow slows down, which in connection with the deflection leads to the heavier parts of the second fraction settling on the floor of the expansion space, while the non-usable light parts are sucked off together with the air through the air outlet 5. This division of the second fraction into a third and a fourth substream is indicated in FIG. 2 again by corresponding arrows III and IV. According to FIG. 1, substream III contains light rolls, essentially weaker grain, sand and a little light parts. In contrast, the partial flow IV consists primarily of air enriched with dust and the like, which is slightly contaminated.

The air withdrawn from the air outlet 5 becomes an air cleaning device in the form of a pre-separator 17, which "can be a centrifugal separator. The pre-separator 17 separates the air sucked out of the housing part 1 in an at least 10% proportion of dirt-saturated air Air and a remainder of relatively purified air. The relatively purified air becomes that again Fan 9 supplied so that there is an air circuit. The dirt-saturated air is removed from the Pre-separator 17 is sucked off and fed to a second cleaning device before being sent to the Atmosphere is given off. The purpose of this is shown in FIG. 2 indicated blower 18 and the cleaning device 19, which can be a cyclone.

The housing part 2 houses collecting devices and screening devices for the first to third Partial flow The screening devices, which are described below in are described individually, are combined into a screen block 20, which by means of an unbalance drive 22 is set in vibration. The material falling in the first partial flow I through the grate 7 downwards meets a collecting surface 23 which is arranged in the housing part 2 under the grate and which carries the first partial flow I to the end of the feed of a first scroll screen 24 directs the scroll screen 24 is designed so that the Grain grains and the fine-grained impurities through the sieve into a collecting funnel 25 fall while the rolls remain on the sieve surface. A channel 26 connects the collecting funnel 25 with a cleaning sieve 27. The fine-grained impurities fall through this cleaning sieve 27. So primarily sand through it, while only the good grain you are looking for is on the sieve remains and passed through a channel, not shown in detail, to Nutzgutauslaß 28 can be. The removal of the parts remaining on the sieves is caused by the Sieves are inclined relative to the horizontal, so that parts remaining on the sieves as a result of the Imbalance drive 22 caused vibrations from the sieve inlet side to the lower sieve outlet side migrate and fall over the edge of the sieve into appropriate collecting devices or channels.

The second partial flow II is collected between collecting and guide surfaces 29 and to a second Scroll screen 30 passed. The second scroll screen 30 lies in the same inclined plane as the first Scroll sieve 24 and connects directly to this. Another is located under the scroll screen 30 Collecting funnel 32, which collects the portion of the second substream that has been cleaned of rolls and via a further channel 33 to a distribution device 34

ίο leads. The distribution facility 34 distributes the second partial flow evenly on three sorting sieves 35 which are arranged one below the other and which correspond in structure. The distribution facility 34 will be described later with reference to FIG. 4 explained in more detail. The sorting sieves 35 are constructed in such a way that only good grains remain on the sieve surfaces, while weaker ones Cereal grains and fine-grained impurities through the sieves into those arranged below Catch trays 36 fall. The good grain falls over the lower-lying edges of the inclined sorting sieves 35 into a channel 37 and via this likewise arrives at the usable material outlet 28 Catched goods, which primarily consist of weaker grain, are not shown another channel is fed to a second outlet 38 and can be used as a second choice material, e.g. B. as feed grain or the like can be used.

Since the first partial flow I already comprises a third to half of the grain portion of the first fraction A , a large sieve surface is available for sorting the remaining grain portion in the second partial flow II. The sorting can therefore be carried out much more effectively and faster than if the division into partial flows I and II had not taken place and the entire first fraction A would have had to be subjected to sorting. Since the first partial flow I already has the desired high degree of purity due to the selection of the position of the peeling plate 15 in relation to the grain quality, the cleaning sieve 27 does not need to carry out any sorting but only cleaning. The sieving performance of the cleaning sieve, that is to say the amount of material to be fed in per unit of area and time, can therefore be very much greater than that of the sorting sieves 35. The greater part of the space available within the device can therefore be occupied with sorting sieves to create the largest possible sorting sieve area. The high screening capacity achieved in this way ensures that the second substream II is properly sorted into good and weaker grain.

As can be seen from Figure 2 are the Sorting sieves 35 arranged above the cleaning sieve 27. The distribution device 34 is located on the in F t g. 2 left, slightly raised ends of the sorting sieves 35. The channel 26, which the first Partial flow I from the collecting funnel 25 to the cleaning sieve 27 is located according to FIG. 2 on the left side of the distribution device 34, so that the first and the second substream without crossing from the The separation point defined by the peeling plate 15 up to the cleaning sieve 27 or the sorting sieves 35 reach. The Schroliensieben 24, 30, 46 are above the sorting sieves 35 and arranged below the collecting surface 23 or the collecting and guide surfaces 29. The common to the cleaning sieve 27 and the sorting sieves 35, the good grain receiving channel 37 is located in accordance with FIG the right side of the lower-lying dispensing ends of the

Cleaning and sorting sieves 27 or 35.

F i g. 3 shows a part of FIG. 3 on an enlarged scale. 2 with the channel 26, the distribution device 34, part of the Cleaning sieve 27 and parts of the sorting sieves 35 and their collecting trays 36. Below the sieves 27 and 35, respectively one recognizes sieve cleaner 39, which consist of rubber balls 40 which are held in a cage 42 so that they dance up and down as the sieve unit oscillates. These dancing rubber balls 40 push against grains or stones or the like that may have got stuck in a sieve opening. the Sieve cleaners are designed in such a way that they prevent the parts passing through the sieves 27 and 35 into the Do not interfere with collecting trays 36 or 43.

F i g. 4 shows the distribution device in a partial longitudinal sectional view according to the line IV-IV in FIG 34. The distribution device 34 is distributed alternately high over the length of the device arranged collecting arches 44. That falling down in the channel 33 evenly over the length of the device Good therefore meets the highest collecting tray 44 in a longitudinal section and in the adjacent one Longitudinal section on the middle collecting tray 44 and in the next but one longitudinal section on the lowest one Collecting tray 44 on. Summed up over the length of the device, it meets the uppermost collecting trays 44 the same amount of material as on the middle and on the lowest collecting trays 44. That on the top Collecting trays 44 falling material is delivered to the top sorting sieve 35, while the middle collecting tray the middle sorting sieve and the lowest collecting trays load the bottom sorting sieve.

As stated earlier, the second fraction entrained with the air flow in the wind readout device can still contain a not inconsiderable portion of usable grain, but at least weaker grain that can be used as feed grain, depending on the quality of the goods fed. This part of the second fraction B is heavier than the light impurities and is therefore deposited as a third partial flow 111 at the bottom of the expansion space 16. This third partial flow falls from an opening in the floor of the expansion space onto a collecting surface 45 underneath. The collecting surface 45 leads the material of the third partial flow III to the feed side of a third scroll sieve 46. The third scroll sieve 46 closes in the same plane as the first two scroll sieves 24 and 30 to the latter. In this way, the three scroll screens form a plane that is slightly inclined with respect to the horizontal, at the highest end of which the heaviest scrolls and at the lowest end the lightest scrolls remain on the screen surface. As already stated, due to the inclination of the sieve surface in connection with its vibration, the rolls migrate from the higher end of the sieve or sieve to the lower, in order to finally fall over the lower end edge of the third roll sieve 46 into a channel 47. The channel 47 leads the rolls to a waste outlet, not shown in detail. The fine-grained impurities that were sieved out of the first partial flow 1 with the aid of the cleaning sieve 27 and collected by the collecting tray 43 are also passed to the same waste outlet. The portion of the third partial flow III passing through the third spiral sieve 46 is collected by a sorting sieve 48 which is arranged directly below the third spiral sieve. Grain grains remain lying on the sorting sieve 48 and, at least in terms of size, are to be counted as good grain. This grain, which also falls into a further channel 49 due to an inclination of the sieve 48, can optionally be brought to the useful material outlet 28, to the second outlet 38 or back to the material inlet 3, depending on the result of a test. The quality of the grain collected in the channel 49 depends on the type of goods delivered, so that the decision for one of the three alternatives mentioned must be made depending on the individual case. The material collected by a collecting tray 50 under the sorting sieve 48, which consists primarily of weaker grain and possibly fine-grained impurities, is fed to the second outlet 38 for material of second choice via a channel (not shown).

The amount of material to be sorted by the sorting sieve 48 is significantly less than the amount of material of the second Partial flow II, so that the area of the sorting sieve 48 is very much smaller than that of the same sieving performance Total area of the sorting sieves 35 can be.

Below the air outlet 5, a pipe 52 opens into the housing part. The tube 52 is an elastic Connecting member 53 with suction pipes 54 and 5.S connected inside the screen block 20, whereby a Dust removal of the screen block is achieved. A window 56 within the housing part 1 enables FIG Connection with a lamp 57 to observe the function of the wind reading device from the outside. This facilitates the optimal setting of the adjustable wind readout parts. The ones provided for each sieve Sieve cleaners 39 are only indicated in FIG

For this purpose 3 sheets of drawings

Claims (22)

Patent claims: 1. Process for cleaning and sorting grain, seeds or similar useful material, at which the mixed material is sorted into two fractions by means of an air stream, of which the first fraction has almost the entire share of the useful goods and the second fraction essentially which contains light impurities, and in which this first fraction is divided into two substreams is divided, of which the first substream is essentially good useful goods and the second substream contains both good and weaker useful goods, characterized in that the second partial flow (II) of a sorting sieve for the purpose of sorting into good and weaker useful goods is subjected and that then the sorted out by the sorting good useful material with the first partial flow (I) is reunited. 2. The method according to claim 1, characterized in that that the first substream (I) before the reunification with that from the sorting sieve coming good useful goods of a cleaning sieve for cleaning fine-grained impurities (e.g. sand) is subjected. 3. The method according to claim 2, characterized in that the cleaning sieve of the first Partial flow (I) with greater sieving capacity, i.e. with more material feed per sieve area and time unit is carried out as the sorting sieving of the second substream (II). 4. The method according to any one of claims 1 to 3, characterized in that the two partial flows (I, II) before the cleaning or sorting sieving of a roll sieving (sieving of coarse components such as thistles, large stones etc.) are subjected. 5. The method according to any one of claims 1 to 4, characterized in that after the separation of the first fraction (A) of the second fraction (B), d. H. the majority of the weaker useful material as well as light impurities such as Bowls and straw are subjected to expansion and / or deflection with the air flow leading to them, whereby the heavier material contained in it such as useful goods including impurities is deposited and the air flow with light contaminants is discharged. 6. The method according to claim 5, characterized in that the deposited heavier material if necessary including heavy contamination, is subjected to a sorting sieve. 7. The method according to claim 6, characterized in that the sorting screen is a scroll screening is connected upstream. 8. The method according to claim 6 or 7, characterized in that the sorting sieving obtained, the good useful good according to grain size, either with this or is combined with the weaker useful good or is returned to the entrance of the process. 9. The method according to any one of claims 5 to 8, characterized in that the air flow with the light soiling is subjected to a first cleaning stage, a predominant one of which Part of the roughly cleaned air flow is returned to the entrance of the process while from it a second air stream enriched with impurities is fed to a further cleaning stage from which this air flow is diverted into the atmosphere and the contaminants in solid form can be removed. 10. Apparatus for cleaning and sorting grain, seeds or the like useful material, for carrying out a method according to claim 1, with a wind reading device which comprises a substantially horizontally arranged and substantially vertically from bottom to top penetrated by an air stream grate over the the feed material is passed away, with a first fraction containing almost the entire portion of the useful material falling through the grate or down behind it, with a separating device that divides the first fraction, seen in the horizontal flow direction of the feed material, into a first, front and divided a second, rear partial flow, and with separate collecting devices for the two partial flows, characterized in that the separating device (15) is arranged so that the first partial flow (I) essentially only good useful goods and the second partial flow (II) good and contains weaker useful material that a sorting screen and this with the collecting device (29) for the second partial flow connecting channel (33) are present, wherein the sorting sieve arrangement sorts out the good useful material from the second partial flow, and that a second and a third channel {26, 37) are present, which the sorted out good Useful material and the first partial flow (I) lead to the same useful material outlet (28). 11. The device according to claim 10, characterized in that the separating device consists of one peeling plate arranged in the horizontal flow direction of the feed material behind the grate (7) (15) exists. 12. The apparatus according to claim 11, characterized in that the peeling plate (15) is one of the Curvature of the crop flow in this area has a corresponding shape. 13. Device according to one of claims 11 or 12, characterized in that the position of the Peeling plate (15) is adjustable. 14. Device according to one of claims 10 to 13, characterized by a first scroll sieve (24) for removing coarse impurities and / or a cleaning screen (27) for removing fine-grained contaminants for the first Partial flow (I), and through a collecting device (23) for the first partial flow with the first The fourth channel connecting the roll screen. 15. The apparatus according to claim 14, characterized by a second scroll screen (30) which the Sorting screen arrangement (35) for removing coarse impurities from the second partial flow (II) is upstream. 16. Device according to one of claims 10 to 15, characterized in that the screen surface of the sorting screen arrangement (35) is a multiple of Sieve area of the cleaning sieve (27) 17. Device according to one of claims 10 to 16, characterized by a third collecting device (36) under the sorting sieve arrangement (35), the weaker useful material falling through and possibly catches fine-grained impurities, and through a fifth channel, which is the third catcher connects to a second outlet (38) 18. Device according to one of claims 10 to 17, characterized by an expansion space (16) in which the air flow entraining the second fraction (B) is deflected and deflected there, the air flow in the expansion space slowing down and the useful goods contained in it and possibly some of the impurities settle and wherein the expansion space has an air outlet (5) through which the remaining contaminants are sucked off with the air and fed to an air cleaning device (17, 18, 19). 19. The device according to claim 18, characterized by an opening in the bottom of the expansion space (16) and a sixth channel connecting this to a third scroll screen (46), through a sorting screen (48) downstream of the third scroll screen and by a fourth collecting device (50) under the sorting sieve, which catches the falling material and leads via another channel to the second outlet (38) 20. The device according to claim 19, characterized in that the good, which is probably the third Scroll sieve (46), but not the sorting sieve (48), by means of appropriate connecting channels optionally to the usable material outlet (28), to the zv / eiten outlet (38) or back to the material inlet (3) can be directed. 21. Apparatus according to claim 19 or 20, characterized in that the three scroll screens (24, 30, 46) are arranged side by side in the same plane. 22. Device according to one of claims 10 to 21, characterized in that the sorting screen arrangement consists of several sieves (35) lying one below the other, and that a distribution device (34) is present, which distributes the second substream (II) evenly to the individual screens Sorting sieve arrangement distributed. 10