WO1993004780A1

WO1993004780A1 - Milling process and installation for its operation

Info

Publication number: WO1993004780A1
Application number: PCT/EP1992/001935
Authority: WO
Inventors: Peter Dyk
Original assignee: Tradepoint Handelsgesellschaft Mit Beschränkter Haftung
Priority date: 1991-08-30
Filing date: 1992-08-24
Publication date: 1993-03-18
Also published as: CH684576A5; AU2439592A

Abstract

The process for the production of flours, flakes of suitable quality or meal from various cereals and grains comprises in succession the processing stages wetting, steeping, dry-husking by means of an abrasive disc husker (9) or wet-husking by means of a wet husking machine, pre-crushing using a pair of crushing rollers (14) and sorting using plane sieves. Milling then takes place in a single pass through an impact pin mill (17) of a single milling stage. The impact pin mill (17) has a plurality of counter-rotating rings of impact pins running at a relative peripheral speed of 50 to 160 m/s. The actual milling process is followed by sieving using a drum sieving machine (22). All these processing stages are operated in a compact installation fitted in a container transportable by road or in several, functionally coupable road transport containers.

Description

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The present invention relates to a grinding process which can be used universally for the production of flours, meal, and at most flakes of suitable quality from various types of cereals and crops. In addition, the invention relates to a special installation for operating the grinding method according to the invention.

In the known grinding processes and grinding plants for the production of flour from cereals and other crops, a large number of specialized processes and plants have been developed, starting from the original, simple grinding stone. Grain, especially wheat, rye and maize, is processed into flour in so-called roller mill in several stages. On the other hand, oats are de-husked on special impact machines, then steamed and then ground or flaked again on rollers. You peel barley, millet and sorghum on emery disc peelers and then grinds the regrind to flakes and grist on flaking rollers or hammer mills. If different grain types and other crops are to be milled and usable ground products of sufficient quality are to be obtained, several different methods have hitherto been used and a complex special system is required to operate each individual method. Every such special system means a high investment that is only worthwhile if the system is used appropriately. In many regions, the harvest of specific cereals or crops is too small to make it worthwhile to buy specific plants. The grain and crops of the harvests are therefore transported from the fields over long distances to the corresponding large mills, in order to be subsequently brought back to the regions of consumption, which often coincide with those of production, as flour, flakes or grist. If there were smaller, universally applicable grinding plants, their locations could be spread regionally and still be sufficiently utilized, so that it would be worthwhile to purchase them and, on top of that, the transport routes for the grain and afterwards the flour products would be considerably shortened. Especially in emerging and developing countries, where the transport routes are not well developed, small grinding plants would be very advantageous if they could be used universally for all types of grain and crops. By using small units, the capacity could be fine-tuned to the circumstances. In contrast, large mills are expensive investments and must be made are operated and maintained by highly qualified personnel. In the event of technical malfunctions, the entire grinding operation of a large mill fails, whereas in the case of a mill composed of several small, independent units, a technical malfunction on a single unit has a less fatal effect on the entire mill.

It is the object of the present invention to provide a grinding process which can be used universally for different types of cereals and crops, which guarantees a suitable grinding quality and which can be operated by means of a compact, mobile system. The grinding process should also allow a longer shelf life of the ground material. Another object of the invention is to provide a system for operating the grinding method according to the invention which is particularly inexpensive to purchase and maintain and simple to operate, so that it can be operated by merely trained personnel. In particular, it is an object of the invention to provide a transportable system of this type.

These objects are achieved on the one hand by a process for the production of flours, possibly flakes of suitable quality or grist of various types of cereals and crops, which is characterized by the characterizing features of patent claim 1, and on the other hand by a system for operating the method according to the invention with the characterizing Features of claim 3. In the drawings, an example of a plant for operating the method according to the invention is shown in a schematic representation, on the basis of which the method is described below. In addition, an example of a system is shown in its concrete structure, this system being accommodated in a 20-foot standard container and thus being easy to transport.

It shows:

Figure 1: A schematic representation of a system with the process-specific workstations according to the invention;

Figure 2: The grinding elements of an impact pin mill according to the invention;

Figure 3: A perspective view of a system according to the invention, which is housed in a 20 foot container.

The method according to the invention is described below with reference to FIG

Procedure explained in detail. The figure shows a running diagram in which all system parts are connected to one another with continuous lines in the direction of flow of the material flow.

The regrind to be processed is emptied from a storage silo or from bags and poured into a pouring channel 1 then brought from a cup elevator 2 into a universal cleaning machine 3. The purpose of this cleaning machine 3 is to separate dust, stones and other impurities from the ground material. In the case of later extracting flour production, about 2-3% of water is added when passing through the now switched on power paddle screw 4. However, if one wants to produce whole flour from the regrind, the product passes through the machine without the addition of water, since for reasons of durability the flour moisture should not exceed 13.5% in this case. The subsequent stand-off cells 5 must be dimensioned so large that there is sufficient time for the network water to penetrate the ground material and penetrate it. This protrusion results in a grinding of the flour grain and better elasticity of the grain shells. Through a dispenser 6 and a bucket elevator 7 with a folding box 8, the grain flow is now conducted - in the case of dry peeling for, for example, barley, sorghum, millet, rice, with whole flour production also wheat, rye and corn - to an emery disc peeler 9, each of which after the set throughput speed, more or less shell rubs off. If you want to produce pull-out flours, mostly from wheat, rye and maize, the grains are fed onto the net peeler 10 by switching the switch 8. By adding water to the grain flow and then rubbing the grains with one another in the agitator cylinder, this machine 10 brings about a simultaneous, intensive penetration of the water through the grain shell and a formation of the grains. All machines and conveying elements in the area of cleaning and peeling equipment are aspirated by central aspiration for the purpose of dust and shell removal. All suction lines in this area lead to a separating cyclone 25 with a built-in low-pressure fan 26.

From the net peeler 10, the regrind passes through a further cup elevator 11 into a small storage container 12 and from there, after a short dwell time, through a feed device 13 to the primary crushing rollers 14. The primary crushing roller 14 has the task of the grain break into sections in order to separate coarse shell parts and the fatty seedling from the other regrind at the downstream sorter 15, primarily when grinding maize. This sorter 15 works by means of vibrating flat screens and can also sort out semolina from the broken ground material. However, if you do not want to sort out partial products, such as when producing whole flour, you can simply go through this machine with no effect by simply removing the sorting sieves. The adjoining separating device 16, consisting of a magnet and a heavy goods trough, has the task of separating iron parts and other foreign bodies. In the subsequent impact pin mill 17, which is driven by two electric motors 25, the ground material is comminuted to the desired particle size in a single pass. FIG. 2 shows the actual grinding elements of an impact pin mill according to the invention in a section through the axis of the driving electric motors 25, 26. On the output shafts 27, 28 of the two opposite electric motors 25,26 a ring washer 29,30 is mounted. The two ring disks 29, 30 lie opposite one another at a short distance and have a common axis of rotation 31. A large number of impact pins 32, 33 are now arranged on each ring disk 29, 30 at right angles to the ring disk surface, so that the impact pins 32 of the one ring disk 29 oppose those 33 of the other washer 30. The baffle pins 32, 33 on each annular disk 29, 30 are arranged in concentric circles with respect to the axis 31, such that, starting from the axis 31 in the radial direction, a ring of baffle pins 32 of the one annular disk 29 is aligned with those 33 of the alternate alternate washer 30 at small intervals. For example, 180 impact pins can be arranged in such concentric circles on each annular disk 29, 30. In the example shown, the washer 29 has three, the washer 30 four concentrically arranged rings of impact pins. Of course, the number of rings can also be larger. The speed of rotation of the impact pins is, depending on the ring in which they are arranged, approximately between 50 to 160 m / s. In grinding operation, the two ring disks 29, 30 now run in opposite directions to one another, so that the individual impact pins 32, 33 of the two ring disks 29, 30 pass each other barely. Depending on the desired fineness of the ground product, various ring disks with correspondingly spaced baffle pins are used. The regrind comes from above through a feed to the center of the grinding disks, where it is broken up by the rotating pins, going from the inside out. It goes without saying that the outer impact pins are subject to greater wear, due to their higher speed than the inner impact pins. The speed and the amount of impingement of the impact pin mill 17 are preferably designed for a fineness with a coarse grain of the flour particles in the range between 50 and 300 μ, preferably between 100 and 250 μ. In the case of the production of whole flour, the coarse particle sizes of the shell particles amount to 1 to 4 mm, preferably 1 to 2 mm.

From the impact pin mill 17, the millbase passes through a suction air stream 18 into a separator cyclone 19. There, the product is separated from the conveying air, which goes to the filter by means of the high-pressure fan 24. The regrind falls through a separating lock 20 onto a folding box 21, where the finished product is already obtained during full flour production. By flipping the flap and thus deflecting the ground material onto the drum sieve machine 22, it is possible to obtain shell parts as the sieve transition and the extract flour parts as the main finished product as sieve diarrhea. The sieve transition (bran) is still fed to the bran spinner 23 in order to increase the yield for extract flour. The flour particles adhering to the shells are thrown off and filter dust from the air filter 24 is returned to the separator cyclone 19 through a separate suction line, thereby ensuring a maximum yield. The system according to the invention can be built inside a container that can be transported by road, as shown in FIG. 3, or can be accommodated in several such containers that can be connected to one another in such a way that a system with a continuous flow of regrind is formed. An entire mill with a daily capacity of 20 tons (800 to 1000 kg / hour) can be accommodated in two 20-foot containers. A mill can then be adjusted to a certain extent in the modular system in terms of capacity, and moreover, when several smaller units are operated, technical malfunctions on a single unit have a less fatal effect, in that only a fraction of the capacity fails, whereas in the event of a malfunction in a large mill, the entire system comes to a standstill. The containers can easily be loaded onto trucks, which makes the system according to the invention mobile and can be moved to the respective locations of its need. All that is required to set up the containers is a foundation or sufficient floor mounting. The system can be put into operation within one to two weeks after installation. Operation and maintenance is so simple that it can be taken over by one or two trained assistants. Neither proven millers nor mechanics are required to monitor and operate the system.

The plant according to the invention and the method operated with it make it possible not only to use a certain type of grain, for example wheat, but also others such as maize or Process sorghum. Whereas three different plants were previously necessary for these three types of grain, wheat, corn and sorghum, the plant according to the invention practically combines three mills in one unit. The investment costs for a system according to the invention, measured in terms of its capacity, are less than half in comparison to a conventional stationary mill. The system can also be set up in a few days. To adapt the system to the processing of a specific type of grain, all that is required is to use the desired sieves with simple manipulations and to control the flow of regrind accordingly by means of the built-in switches. Impurities and foreign bodies are additionally separated from this by suction of more controllable starch, adapted to the respective regrind.

The whole flours milled according to the method according to the invention have a significantly higher durability than conventionally milled flours. If the moisture content is no more than about 12%, the whole flours can be stored in dry and cool stores for up to 9 months, in contrast to about 1 to 2 months with previous full flours.

Claims

1.Procedure for the production of flours, possibly flakes of suitable quality or grist of various types of cereals and field crops, in which the regrind in turn comprises the steps of wetting, standing, drying peeling using an emery disc peeler (9) or wet peeling using a wet peeling machine, pre-crushing using a Crushing roller pair (14) and sorting by means of plane screens, characterized in that the grinding is then carried out in a single pass through an impact pin mill (17) as the only mill stage, the impact pin mill (17) changing at least two counter-rotating ring disks (29, 30) thereon ¬ includes concentric circles to each other baffle pins (32,33), and then at most the sieving by means of a drum screen machine (22).

2. The method according to claim 1, wherein the grinding is carried out by means of an impact pin mill (17) in which the impact pin rings run at a rotational speed of 50 to 160 m / s.

3. Plant for the production of flour, possibly flakes of suitable quality or grist of various types of cereals and crops, characterized in that it includes an impact pin mill (17) as the only mill stage, the impact pin mill (17) having at least two counter-rotating ring disks (29, 30 ) with baffle pins (32, 33) arranged alternately on concentric circles.

4. Plant according to claim 3, characterized in that the only mill stage in the impact pin mill (17) consists of three to ten mutually rotating rings of impact pins (32, 33).

5. Plant according to one of claims 3 or 4, characterized in that it includes upstream of the impact pin mill (17) means for cleaning, wetting and standing of the ground material, and then an emery disc peeler (9) for dry peeling and a wet peeling machine for wet peeling, then a Crushing roller pair (14) for pre-crushing and plane screens for sorting, and downstream of the impact pin mill (17) a drum screening machine (22) for possible screening.

6. System according to claim 5, characterized in that the means for wetting consist of a mesh paddle screw (4) which is mounted on the output side of a cleaning machine (3), and that the means for protruding the Include ground material a stand-off cell (5) for penetration of the net water, to which either a sanding disc peeler (9) or a net peeler is connected via a folding box (6).

7. Plant according to one of claims 3 to 6, characterized gekenn¬ characterized in that to the impact pin mill (17) a screening machine, in particular a drum screening machine (22), and / or a bran spinner (23) are connected.

8. Plant according to claim 6, characterized in that for dust extraction, a separating cyclone (19) with the cleaning machine (3), with the mesh paddle screw (4) and with the emery disc peeler (9) or the mesh peeler is connected.

9 ". Plant according to claim 7, characterized in that a suction air system with a separating cyclone (25) and a folding box (21) for switching over to an output or to one of the sieve (22) or centrifugal systems (23 ) is available.

10. Plant according to one of claims 3 to 9, characterized gekenn¬ characterized in that it is built inside a road transportable container or is housed in several such containers that can be connected to each other in such a way that a system with a continuous flow of regrind is formed.