WO1989004721A1

WO1989004721A1 - Process and device for separating mixed grain

Info

Publication number: WO1989004721A1
Application number: PCT/EP1988/001078
Authority: WO
Inventors: Roman Mueller
Original assignee: Gebrueder Buehler Ag
Priority date: 1987-11-27
Filing date: 1988-11-28
Publication date: 1989-06-01
Also published as: EP0318053B1; AU612759B2; CZ280323B6; BR8807330A; HU208501B; JPH02502351A; KR890701213A; HUT54534A; HU893383D0; DE3873035D1; KR940006018B1; WO1989004722A1; KR890701214A; BR8807331A; JP2530736B2; EP0318054A1; HU204449B; ES2033403T3; SK778288A3; JP2525493B2

Abstract

A process and a device for separating mixed corn, for example for separating heavy admixtures such as stones (28) from grain, in which the grain is conducted in layers over an inclined vibrating layering table surface traversed by a current of air and the layering air is conducted as a circulating air, whereby the circulating air used for layering grain is conducted through separated ducts for the incoming and outgoing air and the ducts are set in vibration in synchronization with the layering table surface.

Description

Method and device for separating grain mixture

The invention relates to a process for separating grain mixture, e.g. for reading out heavy admixtures such as stones from grain material, in which the material is directed in a layered manner over an inclined, air-flowing, vibrating layer table surface, and the layer air is conducted as recirculated air.

From GB-PS 1 536 905 a grain separating device operating in recirculation mode is known, which essentially consists of a vibrating table surface and a stationary box that completely encloses the table surface. In its lower area, the stationary box has a fan, by means of which the air is blown upwards through the table surface. The air flowing out from the top of the table surface is directed laterally between the swinging table surface and the walls of the stationary box back into the fan inlet. The air is circulated. This is called recirculation mode. This has the great advantage that complex aspiration systems with appropriate filter devices for the stratified air. The fact is, however, that to date these air circulation systems have only been able to establish themselves to a very limited extent.

In general, it was found that the devices operating with air recirculation are either complicated in construction or that it is not possible to achieve a sufficient quality of separation, for example a sufficiently high degree of selection for stone selection. The reason for this partly lies in the fact that for the air recirculation mode, compromises are made for the product guidance, especially the introduction and execution of the product, as well as for the air guidance. So that the vibrating table can swing freely, either sufficient play must be provided between the vibrating and the stationary parts, or flexible rubber bands must be attached around the entire table surface, but these have a negative influence on the vibrating behavior of the table. False air regularly interferes with the formation of a good product stratification and thus the success of separating the various good parts. The actually unsolved point was the accumulation of dust, dirt and shell parts within the stationary box. The type of devices mentioned is predominantly those for separating grain and other seeds from third-party stock, for example 1-2% third-party stock is quite common. With throughputs of, for example, 5 to 20 tons per hour, there are also large quantities for the annoying small stock. Therefore forced air systems provide to the operator ^"higher requirements, due to higher expenses for cleaning, otherwise they are problematic from a hygienic point of the theoretical advantages therefore remained only major practical drawbacks often occurred in the known Umluftap- Paraten dust-laden air into the environment.. off because the pressure conditions were not adequately controlled.

The invention has for its object a new in To create a circulating air separation process that allows a high throughput while reducing the disadvantages of the known solutions as much as possible.

The invention is achieved in a generic method in that the circulating air used for the stratification of the material is passed through separate guides for the supply and exhaust air, the. Guides are placed in common vibrations with the shift table surface.

In addition to solving the stated problem, the invention has the advantage of a high separation quality, simple construction and clean operation.

The formation of a vibrating unit of the shift table and air ducts has the very special advantage that with a "little more" of vibrating mass almost every starting point for the deposition of dust etc. is effectively avoided. It is not just the effect of the air that sweeps the dust away. Due to the vibration of all wall parts that come into contact with dust, they are constantly shaken clean.

A particularly surprising advantage for the vibrating unit has been the attachment of the product feeder in the area of the higher table end and the air extraction, for example in the middle area above the bed table, and the air recirculation over the lower area of the bed table. Each of the functions can be geared to the maximum, which until now was only possible with the best individual machines without air circulation. The cascading, oscillating product feed or product feed, widened from top to bottom, ensures full expansion and loosening of the product right from the start, while at the same time functioning as an airlock. The installation of the product feed cascade in the area of the The higher end of the table ensures unobstructed and therefore manageable flow conditions not only through but also above the entire shift table area. The air recirculation in the form of a circulating air supply duct, which is guided around the lower end of the table and opens out below this, also ensures optimal flow conditions. However, it is also very particularly important that the circulating air is guided from shift to shift operation without jolts and essentially without swirls. The recirculated air can now, depending on demand, be cleaned in stationary devices arranged ^¬. Since the air in question remains in the circuit, mechanical cleaning without filtering is sufficient. However, it is also possible to pass only a small proportion of the circulating air into a dust filter. This also has the advantage that the entire system remains under negative pressure to the outside.

For the various other advantageous embodiments, reference is made to claims 2 _β to 7.

The invention further relates to a device for separating grain mixtures, in particular for reading out heavy admixtures, such as stones from grain material, with an air-flowed, oscillatable, inclined shift table with air guides for circulating air operation of the device, and is characterized in that the shift table and the guides for air extraction and air recirculation form a vibrating box.

It was really a surprise for the experts involved that all the disadvantages mentioned at the outset have been eliminated with the new separating device working in the recirculating air mode.

Characterized in that not only the parts necessary for the separation function are set in vibration, but also the supply and exhaust air ducts for the Air, the problem of dusting the device is effectively eliminated. The fine dust simply passes through the device. An easy-to-control swingarm box can be formed, on which each function is given a clear local assignment. The material feed is preferably arranged on the side of the higher end of the shift table. On this side you can pull out the shift tables for service work. The air return is preferably attached to the other lower end side. This can be designed as a flat channel so that air vortex-free air flows out of it and enters the lower table surface. Air extraction is installed in the upper middle area of the box. The good and fluid connection of the vibrating parts with the stationary parts can be done by round fabric or rubber sleeves, as is done in practice with many vibrating machines without problems.

For further advantages, reference is now made to claims 9 to 15.

A very particularly advantageous design idea is that one or two table surfaces can be attached in the same swinging box, the lower table taking over part of the goods of the upper table, and the product transfer can preferably take place at the higher table end.

The upper table surface can also - possibly even additionally - have a trough-shaped depression (stone or manor swamp) with through-openings in the trough bottom to separate the product flow into a heavy and a light fraction in its lower area. In this case, the transfer of goods from the upper to the lower table takes place via a slide arranged in the opposite direction to the main flow direction of the upper table, which slide onto the lower table flows.

With the invention a high degree of grain separation, in particular also stone reading, can be achieved. In addition, little air is advantageously used, and the method and the device are simple and, in particular, not very sensitive to fluctuations in throughput and do not dust inside.

some exemplary embodiments of the invention are explained in more detail below. It shows

1 shows the simplest form of a small table reader for stones, FIG. 2 shows the product feed on the shift table,

3 the same approach as Fig. ^' 1, but with two table surfaces, especially for a large product throughput,

4 shows a solution according to FIG. 1, but with a circulating air duct,

5 shows a solution according to FIG. 3, but with a U air duct,

6 shows the FIG. 5 with circulating air separator,

FIG. 7 is a solution similar to FIG. 3 with the additional formation of two heavy fractions in addition to the

Stone selection,

8 is an embodiment variant of FIG. 7,

FIG. 9 shows a stone sump on the layered table surface, FIG. 10 shows the device as in FIGS. 3, 7 and 8 with the recirculated air duct led through the box.

In the following, reference is now made to FIGS. 1 and 2. 1 shows a basic type for a new stone reader 1, the fresh grain being passed through an inlet 2 to a shift table 3 and from there as cleaned grain via an outlet 4 1 is discharged. A closed hood 5 is arranged above the shift table 3 and has a suction opening 6. The hood 5 forms, together with the shift table 3, an oscillation device 7, which can be set in motion by a vibration exciter 8 with an oscillation component in the direction of the upper end of the shift table 3. The upper end of the layer table 3 is formed by a guide plate 19 as the end separation zone. The whole vibrating unit 7 is supported by spring elements 9 to 10 on a frame 10 which is fixed on a floor 11. Also fixed to the frame 10 is a non-vibrating head piece 12, in which the inlet 2 and an air suction line 13 are attached. In addition, an air quantity adjusting flap 14 for adjusting the air aspirated by the entire stone reader 1 is arranged in the air suction line 13. The connection of the vibrating parts, or the vibrating unit 7 and the head piece 12, takes place via flexible sleeves 15, which are arranged after the inlet 2. 0

When viewed in plan, the layer table 3 preferably has an at least approximately rectangular shape. On the side of the higher end of the shift table, the shift table 3 can be pulled out 5 for service work. The product transfer point extends across the full table width. The width is designated in FIG. 2 with "B", the layer thickness with "D". The formation of a wide-area flow of goods 20, also known as good veils, for the purpose of feeding in goods takes place in two stages. As 0 part of the swinging hood 5, the fresh grain is guided in a distribution box 17. The oscillation promotes the uniform, broad distribution of the grain material in the distribution box 17, which, in order to intensify this effect, is widened downwards and is cascaded. The same purpose is served by a stowage flap 18 which is also provided in the distribution box 17, so that the grain material is then directly onto the guide plate 19 which extends over the entire width of the table and then as a wide-area product stream is passed as a uniform, broad product stream 20 onto the shift table 3. The widespread expansion of the product stream 20 is further supported by the fact that the guide plate 19 has an overflow edge 16 at its free end, that is to say it is trough-shaped. For the pre-separation of heavy and light goods, the trough-shaped guide plate 19 can also have bottom openings for the passage of the heavier admixtures.

The broad, uniform product flow spreading on the shift table 3 is particularly illustrated in FIG. 2. In the same figure, the stratification is deliberately overemphasized. The layer table 3 has a rough mesh screen 21 as product supports and is constructed in a manner known per se in the so-called sandwich construction, the mesh screen 21 forming the upper side, supported by honeycomb-shaped sheet metal strips 34, which are downward through a fine Perforated plate 22 are held. In the individual fields 23 between the metal strips 34, cleaning bodies 24 are arranged which keep both the mesh 21 and the perforated plate 22 clean. It is also important here that the perforated plate 22 has an air resistance that is much greater than the air resistance of the mesh 21, z. B. in the order of 1: 10. With this measure, the air distribution can be kept approximately constant over the entire surface of the layer table 3 regardless of the layer thickness on the mesh screen 21.

The material stratification itself essentially consists of three different layers, a lower, heavy layer 25 containing the heavy admixtures being conveyed upward by the mechanical throwing motion. A light layer 26 freed from the heavy admixtures is kept in suspension not only in the relaxed state but also at a distance above the mesh 21 by the targeted air flow. There the shift table 3 is slightly inclined and the upper one

Light layer 26 does not directly receive an upstream table impulse, but is kept in vibration, it swims towards the lower table side. In addition, the inclination of the shift table 3 can be adjusted by an adjusting device 35. A third stratification 27 consists of the actual heavy admixtures, mostly only individual particles, individual foreign bodies, stones 28, etc. Good, heavy grains 29 .and light parts, e.g. B. half grains, shell parts 30 are shown in the approximately corresponding shape. ' The heavy goods with the stones 28 immediately sink onto the vibrating table surface 7 and move up the table due to the vibration and the rough table surface designed as a mesh 21.

For the function described, it is now important that the air flow is guided correctly. The entire layer table surface is flowed through uniformly from bottom to top by a suction air flow, the direction of flow of which is illustrated by arrows 31. This air flow 31 brings the grain to a highly fluidized state. Since only the heaviest parts, i.e. H. the stones 28 are separated onto the higher end of the table and are to be conveyed from there into a stone lock 45, a corresponding blowback stream 33 is formed, which prevents light parts or grains with the heaviest admixtures from being conveyed upwards. The blow-back stream is preferably formed under the guide plate 19. If the guide plate 19 is firmly connected to the hood wall, the air guided into the slot between the guide plate and the shift table can only escape in the direction 33.

With the exception of the stones 28 located therein, the material is prevented from moving further upwards by the air flow in front of the final separation zone. The stones 28 can continue their movement towards the higher end of the table. Zen.

The same blow-back flow 33 causes a flow front or flow direction reversal 32 which is clearly established in practice. At the location of the flow direction reversal 32, the grain 29 freed from the stones 28 is lifted off the table surface by the strong air flow 31, 33 and now flows freely together with all light goods with the upper lifted light layer 26 down the table. The lightest fraction is discharged immediately at outlet 4; an average grain fraction can possibly make a circular traveling movement up-table-down several times, which is particularly true for boundary grains.

In FIGS. 1 and 2, the product stream 20 is fed directly into the zone of the flow direction reversal 32. The flow direction reversal 32 is generated from the three forces of mechanical conveying action upstream of the table, floating off the upper layer 26 downward from the table, and blowback flow 33.

The main structural difference between FIG. 3 and FIG. 1 is that in FIG. 3 two shift tables, an upper shift table 3a and a lower shift table 3b are used. Basically, both shift tables 3a and 3b have the same structure, e.g. B. as in FIG. 2. In principle, the blow-back flow 33 is absent from the upper layer 3a, so that not only the heaviest admixtures but also the entire heavy layer 25 are moved up the table and can fall onto the guide plate 19 through a discharge channel 40 via a steering plate 41. Starting from the guide plate 19, the mode of operation of the shift table 3b is identical to that of the shift table 3 of FIG. 1, respectively 2.

To prevent the freshly entering product stream 20 from the distribution box 17 from being mixed directly with the heavy layer 25, there is between the distribution box 17 and the layer table 3a, a guide plate 42 is arranged at the uppermost point.

The flowing product stream is discharged via a product lock 43 directly into an outlet channel 44 of the lower layer table 3b. The two streams of material from the two shift tables 3a and 3b freed from the heaviest admixtures are then brought together again in the outlet 4. All the heaviest admixtures, such as stones 28, etc., are first separated from the upper layer table 3a together with the heavy layer 25. The actual separation and the separate removal of the stones 28 via the stone lock 45 then take place on the lower layer table 3b. The stone selection takes place here in two temporally and spatially separated stages. This is because concentrate is first formed with all heavy goods, e.g. B. 30% to 60% of the whole Gutdurchsatzes on the upper Schicht¬ table 3a and only from the reduced Gutdurσhsatz ^'are read out the stones and other hardest impurities and led away separately.

FIG. 4 is identical to FIG. 1 in terms of product management, and FIG. 5 corresponds to FIG. 3. The solution concept of FIGS. 4 and 5 additionally contains a box 50 which is closed all round, which can be closed by the, respectively the shift table (s) is divided into an upper suction chamber 51 and a lower suction chamber 52. At the lower end of the or the layer table (s) there is a recirculation channel 53, which is connected to an air return line 55 via a flexible hose 54 and an air return pipe 55 '. An air flow restrictor 56 is arranged in the air return line 55. 4 and 5, the box 50 itself is supported on the fixed frame 10 by means of spring elements 9. On the top of the box 50 there is on one end side an inlet spout 2 'which adjoins the inlet 2, approximately in the middle an outlet nozzle which is connected to the air outlet line 13 13 'and an air return connection 55' connected to the air return line 55 is arranged on the opposite end side. The aforementioned connections 2 ', 13', 55 'are connected via flexible sleeves 15, 54 on the one hand to the non-oscillating head piece 12 and on the other hand to the box 50 in order to be able to participate in its movement in this way. In the double machine in Fig. 5, two outlets 4 are arranged as tubular product channels 57 on both sides (perpendicular to the image plane), so that the remaining space between the two Produktka¬ nälen 5 ^• remains for the recirculation passage 53. The box 50- is bordered in Figures 4 and 5 for better identification with a dashed line.

In addition to FIGS. 4 and 5, FIG. 6 additionally shows a circulating air separator 60 with a suction fan 61 and a motor drive 62. The air extraction nozzle 13 leads directly into the air separator 60, the essential or disruptive part of fine shells and dust being removed from the air flow via a dust discharge line 64.

In most cases in which recirculated air is used, air cleaning is advantageous because it can effectively avoid dust accumulation in the entire device and increase operational safety and hygiene. The recirculation mode has the great advantage that only a minimal amount of air, e.g. B. 10% of the circulating air volume must be passed through fine dust filters. For this purpose, an aspiration connection 65 is provided. The circulating air separator 60 can be attached directly to the ceiling 66 with a fan.

FIG. 7 has a fundamental difference compared to FIG. 3 in that only a small part of the material throughput from the upper shift table 3c at the highest point through a row of larger holes 71 over the entire table width in FIG. 7 , to at the bottom of the upper zone of the direction of flow reversal of the lower layer table 3d. The majority of the heavy goods are guided in the area of the lower end of the table via a chute 72 approximately to the middle of the lower layer table 3d, again over the entire width of the table. Many series of measurements have shown that, with this solution, the large part of the stones is nevertheless released through the holes 71 directly onto the lower layer table 3d. In the solutions according to FIGS. 7 and 8, it is important that the upper layer table has only a less rough surface than the lower layer table 3d, as shown in FIG. 9, by the upper layer table 3c made of perforated sheet metal and the lower one Layer table 3d is formed from mesh.

A particularly interesting, independent idea is now shown in FIGS. 8 and 9. This is the use of a stone sump 80 in the area of the upper layer table 3c. The method of operation is as follows: The stone sump 80 consists of a trough-like depression 81 which extends over the entire width of the layer table 3c. Similar to FIG. 2, two different layers are formed in FIGS. 8 and 9, namely the heavy layer 25 and the light layer 26 freed from the heavy additives.

Because the surface of the upper layer table 13 has only a slight roughness, there is no actual upward flow; at least the whole heavy layer 25 cannot be moved up. Rather, the lower heavy layer 25 flows down the table with a considerable delay, as is indicated by the single arrow 82. In contrast, the light layer 26 flows down the table at high speed (double arrow 83). The heavy layer now sinks, once it has reached the area of the recess 81, into the stone sump 80. The stone sump 80 now has a number of through openings 84 on its bottom, through which part of the material passes is continuously discharged together with the stones onto the underlying slide 72 or the lower layer table 3d. With the correct coordination of the number of effective diaphragm openings 84 in relation to the mass flow of the heavy layer, the light and heavy layers can be separated such that the heavy layer 25 continuously sinks completely into the stone sump 80 and is discharged directly downwards. This has two major advantages:

1. This results in a very high degree of selection for the heaviest admixtures (stones, etc.)

2. In addition to separating the heaviest admixtures, it can be separated into a clean heavy fraction (good grains) and the rest into a light good fraction (shells, grainy and broken grains) with only a minimal additional effort.

This makes it possible to separate the different basic fractions (stones, etc., heavy, light) in a single device and with very high quality.

Finally, FIG. 10 shows a device which functions according to the same principles as the devices according to FIGS. 3, 7 and 8. For this reason, there is no need to repeat the description of the same components at this point. The device according to FIG. 10 differs from the aforementioned devices only in that a recirculating air duct 53 is arranged separately in the box 50, and the influence it has on the flow properties of the air in the box 50 can be avoided.

Claims

1. Process for separating grain mixture, e.g. for reading out heavy admixtures such as stones (28) from grain material, in which the material is essentially layered and passed over an inclined, air-flowing, oscillating layer table surface and the layer air is conducted as recirculating air, characterized in that the layering of the Good used recirculated air is passed through separate guides for the supply and exhaust air, whereby the guides are set in common vibrations with the screen surface.

2. The method according to claim 1, characterized in that the guides together with the shift table (3; 3a, 3b; 3c, 3d) form a box (50) which is set in vibration.

A method according to claim 1 or 2, characterized gekenn¬ characterized in that a stationary platform (12) and above a stationary fan (61) is arranged above the vibrating box (50), wherein the air circulation on the circulating air is maintained by the fan (61) .

4. The method according wenigstensn one of ^• preceding claims, characterized in that a portion of the grain mixture to a ^'table below the layer (3a; 3c) disposed further stratification table (3b; 3d) is passed, wherein the circulating air flows through both of bed tables.

5. The method according to at least one of claims 1 to

4, characterized in that the material as a broad-area stream in the area of the higher

The end of the table is fed in, the exhaust air is discharged in the middle at the top and the supply air is fed back over a large area in the area of the lower end of the shift table.

6. The method according to at least one of claims 2 to

5, characterized in that the material is fed in as a uniform falling stream which extends over the entire table width and the material feed (17, 19) provided for this purpose is firmly connected to the oscillating box (50) as a cascade widened from top to bottom.

7. The method according to at least one of claims 1 to

6, characterized in that the circulating air in the area above the central air discharge (13 ') in stationary arranged elements of dust parts is cleaned.

8. Device for separating grain mixtures, in particular for reading out heavy admixtures, such as stones (28), from grain material with an air-flowed, inclined layer table (3; 3a, 3b; 3c, 3d) that can be set into vibration with air - Guides (13 ', 53) for circulating air operation of the device. characterized in that the shooting table (3; 3a, 3b; 3c, 3d) .as well as the

Guides (13 ', 53) for the air suction and for the air return form an oscillating box (50).

9. The device according to claim 8, characterized in that within the box (50) are provided: an air suction space (51) above the layer table (3; 3a; 3σ) and a separate air supply duct (53) which in the area of lower end of the shift table (3; 3b; 3d) opens.

10. Apparatus according to claim 8 or 9, characterized in that a cascade-like Gutzufüh- (17, 19) part of the vibrating box (50), which is arranged in the region of the higher table end, is widened from top to bottom.

11. The device according to at least one of claims 8 to 10, characterized in that on the top of the box (50) at one end a Guteinlauf- connection (2 '), approximately in the middle an Luftabsaugstut¬ zen (13') and at an air return pipe (55 ') is arranged on the opposite end side.

12. The device according to at least one of claims 8 to 11, characterized in that in the box (50) at least two layer tables (3a, 3b; 3c, 3d) are arranged one above the other, the circulating air flowing through both strata from bottom to top, and a product transfer (40, 19; 43; 71; 72; 81, 84) for transferring a part of the goods of the top strata table (3a; 3c) to the bottom

Layer table (3b; 3d) is provided.

13. The device according to at least one of claims 8 to 12, characterized in that the material supply and / or the product transfer over the whole

Width of the shift table (3; 3b; 3d) opens, and the mouth has a guide plate (19) arranged at a distance above the shift table (3; 3b; 3d).

14. The device according to at least one of claims 8 to 13, characterized in that the box (50) is capable of swinging on a frame (10) which has a stationary head piece (12) in its upper region.

15. The apparatus according to claim 14, characterized gekennzeich¬ net that between the stationary head piece (12) on the one hand and the air extraction nozzle (13 ') or the air return nozzle (55') and the Guteinlaufstut¬ zen (2 ') on the other hand of the vibrating box ( 50) flexible cuffs (15; 54) are arranged.

16. The apparatus according to claim 14 or 15, characterized in that above the stationary

Head piece (12) a circulating air separator (60) is arranged.

17. The apparatus according to claim 16, characterized in that the circulating air separator (60) with a

Suction fan (61) and connected to a dust guide line (64).

18. The device according to at least one of claims 8 to 17, characterized in that the circulating air duct (53) is connected to an aspiration connection (65) for fine dust filters.