SK282590B6 - Device for production of flour, semolina and the like milling pro ducts - Google Patents

Abstract

Device for production of flour, semolina and the like milling products of corn and field crops contains front-end cleaning system (1), scourer (2) and steaming system (3) for moistening the grains. These systems are followed by first grinding through at least one double roller stool (4) and multi-stage sieving in the multi-stage sieve system (5). In this system the intermediates containing dark components, intermediates containing scales and others containing endosperm, are separated into three fractions and then at least two fractions are ground separately exclusively in the plug mills (13, 20). To the simple effects of the first plug mill (13) the wipe-outs (11) of the bran can be prefixed. Second plug mills (21) with two mutually opposite rotors (with double impact) are used for fine grinding.

Description

Technical field

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plant for the production of flour, meal and similar mill products from cereals and other field crops, equipped with at least one cleaning, peeling and sieving stage for preparation for the milling process. , peel-containing intermediates and white endosperm.

BACKGROUND OF THE INVENTION

In known flour production plants, the grain is first cleaned and peeled. This is followed by a grinding process with a large number of different grinding steps and the subsequent sieving steps. Grain kernels deprived of coarse husks are screened, using a sieve set, to fine flour and also to various fine other fractions, ranging from products rich in husks, bran to semolina and coarse flour, the different coarse fractions being then fed to different other grinding steps and subsequent sieving steps. Coarser grain constituents pass through many grinding stages in known plants. Each of these grinding steps comprises a number of cylindrical stands, each having two mutually opposed and different speeds rotating rollers, between which the grind is ground. The roller stands must be individually adjusted to achieve the required roller spacing in their parallel guide as well as the required roller speed. The coarse fraction remaining after the grinding steps falls off in the form of bran. The fines obtained after the grinding steps differ from each other in the quality and content of carbohydrates, proteins, enzymes, minerals and the like, and at the end of the milling product production process they are divided into individual or several different types and qualities of flour. Known plants for the production of bakery flours typically contain about eighteen grinding stages, including auxiliary equipment, and are therefore expensive. In order to produce plump, large and crispy types of sourdough bread which are well sold, such increased costs are considered necessary. Production of particularly white flour is also costly.

Known multi-stage modern machines with cylindrical stools, fitted with pairs of rolls, for the production of flour suitable for the preparation of baked goods have evolved from old millers in which the grain was ground between millstones in the form of horizontal discs. Also in these plants, multiple passes of coarser grinding material between the grinding stones, i.e. several pairs of millstones or several grinding steps, are required to produce sufficiently fine flour.

In addition, it is known to use pin grinding devices with impact pins in grinding devices in the form of teeth interlocking and mounted on mutually opposed coaxial disks or rotors. In these devices, the grinding material is fed into the space between the disks in the axial direction, where it is shattered by multiple impacts of the pins and after grinding it is removed from the grinding space in a tangential direction by centrifugal forces. These pin mills, operating at high peripheral or impact velocities, have hitherto been used to grind tough, hard-to-grind grinds, for example, to produce oatmeal from husked oat.

EP 0 418 801 A1 discloses a grinding method and an apparatus for carrying out this grinding method, in which the intermediate product is divided into only one sieve overflow and one sub-base after the roller stand. The sieve overflow contains only one fraction of the mixture. This mixture is first ground in a pin mill and then screened or sieved and re-milled on a roller mill. By unsorted co-milling in a pin mill, the semolina is ground together with the skins. The fine particles thus obtained can be sorted by size and weight, but due to their small dimensions and weights it is not possible to achieve a clear separation into the particles of husk and semolina.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a device of the above-mentioned type which allows the milling of particularly white flour types without having to arrange a plurality of successive two-roll grinding mills which require significant manufacturing, operating, maintenance and adjustment costs. Especially in developing countries, there is an increased demand for white flour. However, it is in these areas that there is a lack of skilled personnel for the operation of known devices requiring precise adjustment that would be suitable for the production of white flour.

SUMMARY OF THE INVENTION

These objects are solved by the device according to the invention, which consists in that at least two of the fractions are connected to at least one associated pin mill and the pin mills grind these fractions separately from one another, in particular in only one grinding stage. Thus, before milling in pin mills, the intermediate product is separated into at least three fractions by means of a sieving apparatus and then the separated fractions containing the husk and the semolina are each ground separately in their own separate pin mill. The resulting product then falls out separately and is sorted so that the quality achieved is substantially better due to the unambiguous prior separation into peel and semolina.

In the previous fine co-milling in a single pin mill, which has been carried out to date by a known method, and in the subsequent separation of husks and semolina, it is not possible to achieve approximately results as in the apparatus according to the invention. There is no need to equip the machine with additional double roller stands for each fraction that would require cost multiplication. The role of these additional cylindrical stools is always taken up by a single pin mill with impact pins, and it is of course possible to deliberately bring the fractions to the next stage in order to achieve the desired flour quality. Roller mills with pairs of rollers in the region of the pre-grinding stage do not have high adjustment requirements and are used for pre-crushing, followed by screening the grinding on sieves into dark skin products and white products containing endosperm. During the sieving, all the particles already having the size of the usual flour particles (<200 µm) are simultaneously separated from the white product. The remaining white and dark portions are then milled separately and screened according to the invention, using pin mills instead of a group of mill mills. By this separation, very white flour (T 450 - 700) can be produced from a light portion and dark flour (T 1300-1700) is obtained from a dark portion.

In a preferred embodiment of the device according to the invention, when a single-acting pin mill is used, in particular in the case of milling of husks, the pin mill is preceded by a scraper. This rotates the adhering particles of flour from the skins and at the same time separates the particles from the skins. It is also advantageous if fan separators or semolina purification machines are connected to the multi-stage screening system and the outlets to the separate fractions are each connected to one pin mill. The placement of fan traps between fraction sieves in the sifter and pin mills allows particularly good separation of the pure white flour components. Optimization of the milling results, despite the removal of the mill stands from the actual grinding process, can be achieved by equipping the apparatus for grinding white fractions containing endosperm with a pin mill with mutually opposing rotors, the circumferential velocities of the pins being in particular from 60 to 150 m / s.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the device according to the invention is shown schematically in the drawing where a block diagram of the device is shown.

DETAILED DESCRIPTION OF THE INVENTION

The apparatus for producing ground crop products, such as wheat flour, meal, meal, corn flour, bran and mixed products, comprises a first stage for the preparation of processed cereals, comprising a cleaning device 1 intended to remove foreign matter such as stones, peeling devices 2, in which the abrasion removes the cellulosic surface layer, and the dewhead device 3, which condition the grains for subsequent processing. By separating for two to three hours, the separation of thicker skins can be facilitated in this wet production process. On one or more double roller stands 4 grinding of the grinding material is carried out, followed by sorting on a multi-stage sieving device 5. In an exemplary embodiment, two sieving stages 6, 7, 8, 9 are connected to each other with a mesh size of 1000 pm, 560 pm, 315 pm, 150 pm. All fractions which fall off after passing the ground material through the pre-stages 1 to 4 in the form of flour can be taken from the outlet 10 and discharged to the packaging machine.

The fractions from the first sieve stage 6 into a bran scraper 11 which separates the bran from the flour. The product of this device (e.g. corn bran) can then be filled as the first result product into sacks 12. For wheat and other field crops, the deburring machine 11 is followed by a pin separating device 15, which is provided with a fixed disc with impact pins. its circular surface and the opposed driven rotor with impact pins arranged on concentric circles on the circular surface of the rotor. The feed fraction is milled due to the high peripheral velocity of the impact pins moving around the stationary parts of the apparatus, the product of this process being separated by sieves of 14.15 (e.g. 180 pm) into wheat bran and wheat flour (T 1300 - 1700) and can be filled into bag 16,

17th

The fractions obtained from the second screening stage 7 are fed to a fan separator 18, to which the outlet of the third screening stage 8 may also be fed. Two different fractions are discharged from this fan separator 18, the coarse fraction being fed to the pin mill 15 and cleaned. the fine fraction is fed either to the sacks 19, for example, or is further milled in a pin mill 20 with rotors 21 fitted with mutually opposing projecting pins. The product of this milling operation is sorted into individual fractions by sieves 22, 23, 24, 25, 26, the sieves having a mesh size of, for example, 180 µm and 300 µm, respectively. The products are filled into the first bags 27 (e.g., wheat flour T 660-750), the second bags 88 (e.g., wheat flour T-800) and the third bags 89 for wheat flour and finer wheat bran). The coarse and in any case undesirable fraction can be fed back to the inlet of the second pin mill 20.

By making the cross connections, for example represented by the conveyor shaft 30, it is possible to arbitrarily combine the intermediate products and thereby adjust any output quality of the milling products. As with conventional grinding machines, the transport between the individual stations is provided by fans, which are not shown in the drawings in the examples.

Since the main grinding stage downstream of the multi-stage sifting device 5 comprises exclusively single- or double-acting pin mills 13.20, but does not contain any series arrangement of roller mills, the construction of the device is simple and operational and also re-starting, for example problems. For example, in a container embodiment, the device according to the invention can be easily operated by trained operators.

Claims (4)

PATENT CLAIMS 1. Installations for the production of flour, meal and similar mill products of cereals and similar field crops, equipped with at least one cleaning, peeling and sieving stage for preparation for the milling process and containing milling stools for pre-crushing and sieves for separating at least three fractions of dark intermediates; of the intermediate products containing peel and light endosperm components, characterized in that at least two of the fractions are each connected to at least one associated pin mill (13, 20) and the pin mills (13, 20) separate these fractions separately from each other only one grinding stage. Apparatus according to claim 1, characterized in that, when a single-action pin mill (13) is used, in particular for grinding the husks, the pin mill (13) is preceded by a burr (11). Device according to claim 1 or 2, characterized in that fan separators (18) are connected to the multistage screening device (5) or the grits are cleaned and the outlets to the separate fractions are each connected to one pin mill (13). , 20). Apparatus according to claims 1 to 3, characterized in that it comprises a second pin mill (20) with counter-rotating rotors for grinding the light components containing the endosperm, the peripheral speed of the pins being in particular 60 to 150 m / s.