RU2669305C1 - Mill and method of milling loose materials - Google Patents

Abstract

FIELD: technological processes.SUBSTANCE: invention relates to technological processes for the production of food products, namely, to mills for bulk materials, and can be used to produce flour from cereals, milling mineral materials or obtaining powdered sugar. Mill comprises receiving funnel (1), horizontal rotating shaft (2), grinding chamber (4) in which hammers (10) loosely attached to rotating shaft (2) are located, and an air pipe with discharge turbine (3). Rotating shaft (2) is hollow and forms an air duct, which through the holes in the walls is brought into the cavity of grinding chamber (4). Cavity is communicated through the window (14) in the rear wall with calibration chamber (5), along which rotating shaft (2) passes. Receiving funnel (1) is connected to the axial part of grinding chamber (4) inside the primary processing unit. Block is formed by a set of nested perforated sleeves (6–9), some of them are alternately attached to the front fixed wall of grinding chamber (4), others to rotating shaft (2). Loose material cut into the pretreatment block is further destroyed by hammers (10) in grinding chamber (4), where the grinding products are sorted by centrifugal force in terms of density and sail parameters. Particles with the required parameters by air flow from the holes in the walls of hollow rotating shaft (2) through window (14) in the rear wall are transferred to calibration chamber (5), and the larger particles continue to be ground until the required parameters are reached.EFFECT: improved product quality.5 cl, 1 dwg

Description

The invention relates to technological processes for the production of food products, namely, mills for bulk materials, and can be used to obtain flour from cereals (wheat, rye, barley, buckwheat, rice, oats, corn, etc.), grinding of mineral materials ( chalk, talc) or powdered sugar, and also, if the mill is equipped with a cooling jacket, to grind frozen spices.

In the classical method of producing flour in roller mills, grain grinding occurs due to compression and shear forces when rolling cereals between corrugated shafts rotating at different speeds. The process has to be carried out in several (up to six) stages. This is done in order to avoid crushing the cellulose of the casing, which after each grinding has to be blown off on sieve machines and sieved in sieving systems. In total, a minimum of 15 pieces of equipment are used in a standard flour-grinding line (6 roller machines, detacher, entoleitor, 5 strainer machines, grinding machine, sieving). The main disadvantages of this technical solution are complexity and high material consumption. A large number of different equipment leads to the need for maintenance staff, the construction of individual buildings and transport systems.

Closest to the technical nature of the proposed device is a mill containing a receiving funnel, a horizontal rotating shaft, a grinding chamber in which hammers are freely attached to the rotating shaft, and an air duct with an injection turbine (see patent CN 104415820, class B02C 13/02 published on 03/18/2015). The main disadvantage of the known device is the lack of classification of the grinding product according to particle size after winding. The criterion for the sufficiency of grinding is the size of the cell of the outer contour, so it is possible to obtain only wallpaper flour. In addition, the known technical solution involves grinding to a certain size of the finished product, and when grinding, the resulting product will include either all parts of the grain in a crushed form (wallpaper flour), or by means of preliminary operations only starch-containing endosperm (high-grade flour) will be sent to the grinding .

A technical problem is the need to eliminate this drawback and create a compact grinding machine that uses the speed of particles in the air flow as a criterion for the sufficiency of grinding, which can be used, for example, to organize varietal and multi-grain grinding directly in farms (grain producers), or at points flour consumption (bakeries, confectionery). The technical result consists in improving the quality of the resulting product.

The problem is solved, and the technical result is achieved in part of the device by the fact that in a mill containing a receiving funnel, a horizontal rotating shaft, a grinding chamber, in which hammers are freely attached to the rotating shaft, and an air duct with an injection turbine, said rotating shaft is made hollow and forms an air duct, which through holes in the walls leads into the cavity of the grinding chamber, communicating through a window in the rear wall with a calibration chamber, along the axis of which passes the specified shaft, and the receiving funnel is brought to the axial part of the grinding chamber inside the primary processing unit, formed by a set of perforated bushings nested in each other, which are alternately attached one to the front fixed wall of the grinding chamber, the other to the rotating shaft, and the diameter of the perforation holes decreases from inner sleeve to the outer. The hammers can be attached to the shaft using a drum mounted on it, covering the outer sleeve of the primary processing unit. A screw attached to a rotating shaft may be located in the inner sleeve. The calibration chamber can be equipped with a grid separating two independent descents.

The problem posed is solved, and the technical result is achieved in part of the method by the fact that according to the proposed method of grinding bulk materials using the mill described above, the bulk material cut in the pre-processing unit is subjected to further destruction with the help of hammers in the grinding chamber, where the products of grinding are sorted by the density and windage parameters and using the air flow from the holes in the walls of the hollow rotating shaft transfer particles with the required pairs through a window in the back wall to the calibration chamber, and larger particles continue to grind until the required parameters are achieved.

The drawing shows a cross section of the proposed mill.

The proposed mill consists of a receiving funnel 1, a primary processing unit, a hollow horizontal rotating shaft 2, forming an air duct with an injection turbine 3, a grinding chamber 4 and a calibration chamber 5.

The receiving funnel 1 is brought to the axial part of the chamber 4 inside the primary processing unit, formed by a set of perforated bushings 6-9 nested into each other. The bushings 6, 8 are attached to the front fixed wall of the grinding chamber 4, and the bushings 7, 9 are attached to the rotating shaft 2. The diameter of the perforation holes decreases from the inner sleeve 6 to the outer sleeve 9. In the chamber 4 are hammers 10, which are freely attached to the shaft 2 with the help of a drum 11 mounted thereon, covering the sleeve 9. In the sleeve 6 there is a screw 12 attached to the shaft 2.

The duct formed by the cavity of the shaft 2 through the openings 13 in the walls is connected to the cavity of the grinding chamber 4, which through the window 14 in the rear wall communicates with the calibration chamber 5. The shaft 2 passes along the single axis of the chambers 4 and 5. A mesh 15 is located inside the calibration chamber 5, separating two independent descents 16 and 17.

The proposed mill on the example of grinding grain works and implements the proposed method as follows.

The grain purified from metal and mineral impurities is fed to a receiving funnel 1, from which the screw 12 is distributed over the internal stationary perforated sleeve 6. The holes in the sleeve 6 are made based on the maximum possible size of the crushed product (for wheat 9 mm, for corn 12 mm). The number of holes in the sleeve 6 determines the feed rate of the bulk material and is selected for the performance of the mill. The grains that have fallen into the holes of the sleeve 6 abut against a rotating perforated sleeve 7 having a smaller diameter of the holes. The protruding parts of the grain, penetrated into the holes of the sleeve 7, when the shaft is rotated, are cut and fall to a stationary sleeve 8, which has even finer perforation. The crushed particles with a size smaller than the diameter of the holes of the sleeve 8 are advanced further towards the movable sleeve 9, and the particles with a large diameter are crushed by analogy with the process at the border of 6 and 7 of the bushings. The cutting process occurs at the boundaries of the bushings 6-7, 7-8, 8-9, as a result, grain particles with a size not exceeding the diameter of the holes of the sleeve 9 fall into the chamber 4 with corrugated walls, inside which the drum 11 rotates with freely suspended hammers 10. Further the destruction of grain particles is carried out by free blows of hammers 10 and reflected blows of particles on the flutes of the lateral cylindrical wall of the chamber 4. The impact speed is selected based on the sufficiency for breaking the starch grains, but no more, to avoid grinding fibrous (more durable) parts of the grain.

An integrated turbine 3 through the chamber 4 creates air movement from the openings 13 to the window 14. Due to the centrifugal force, the grinding products are sorted according to the density and windage parameters: particles with a higher density and lower windage are located at the walls of the chamber 4, and light particles with a lower density are moved closer to the axis. Particles with the required parameters (density and windage), whose rate of rotation has decreased to the air flow rate from the openings 13, is transferred with this flow to the calibration chamber 5. Thus, parts of the milled endosperm are removed from the grinding zone in small form, and parts of the shells in the form large flakes, while larger starch grains and bran flakes with an unseparated endosperm continue to grind in chamber 4 until the desired parameters are achieved. In the chamber 5, flour is sifted through the mesh 15 into the gathering 16, from bran and non-grind, discharged into the gathering 17.

Thus, the proposed method of grinding consists in the phased destruction of bulk materials with the constant removal of air products of grinding into the zone of separation according to size. The method is based on differences in the nature of the destruction of crystalline starch and fibrous cellulose, as well as the unequal behavior of their particles in the air stream.

In the proposed method, the primary cutting of grain occurs in the block of bushings 6-9, i.e. immediately when it is fed into the grinding chamber 4, where particles are subsequently crushed by free blow in an upward air flow. The impact speed is selected in such a way that the destruction of starch occurs along the grain boundary, and its particles acquire a streamlined shape, while the cellulose-containing particles of the shell, separated from the grain, remain flakes. The difference in the shape of the particles leads to the fact that when blowing them with an upward flow of air, the particles of the shell, having a higher coefficient of aerodynamic drag, are removed earlier than the particles of the endosperm, which undergoes additional grinding. As a result, an air stream filled with flour and bran, passing through a sieve 15, carries small particles into one gathering 16, and large particles fall into another gathering 17.

In the production of flour from gymnosperms or prepared cereals, there are a number of obvious advantages:

- particles of the embryo and the aleuron layer, which are sources of vitamins and fiber, remain in the finished product, and are not thrown out with bran;

- the production of baking mixtures from several cereals does not require separate production and further mixing (when grinding in roll mills, each crop requires its own angle of cutting corrugations on the rolls);

- production is carried out in one go.

Due to the differentiated destruction of grain elements and grinding according to the aerodynamic properties of the particles of the crushed product, the proposed technical solution, using one unit of equipment, allows not only to improve the baking quality of the obtained flour, but also to make them individually ordered. The energy costs of direct grinding and sorting are similar to classical technology due to the objectivity of physical laws. However, the exclusion from the production process of the need to move intermediate products between different units of equipment (the route is measured in kilometers) leads to overall savings not only on the cost of transport systems, but also on their energy consumption.

An important advantage of the proposed technology is also its compactness, which allows saving on capital costs associated with the construction of large factories and infrastructure. The equipment is easily placed in small rooms, not necessary for external operating conditions. You can start the equipment both in the zone of growth of raw materials and in the areas of processing of the finished product. You can even include it in existing mealy raw material processing lines.

The proposed mill was implemented in metal and successfully passed tests on various types of raw materials.

Claims (5)

1. A mill containing a receiving funnel, a horizontal rotating shaft, a grinding chamber, in which hammers are freely attached to the rotating shaft, and an air duct with an injection turbine, characterized in that said rotating shaft is hollow and forms an air duct that is connected through openings in the walls into the cavity of the grinding chamber, communicating through a window in the rear wall with a calibration chamber, along the axis of which the specified shaft passes, and the receiving funnel is brought to the axial part of the grinding chamber measures inside the primary processing unit, formed by a set of nested perforated plugs, which are alternately attached to one - the front fixed wall of the grinding chamber, the other - to the rotary shaft, the diameter of perforation holes decreases from the inner to the outer sleeve. 2. The mill according to claim 1, characterized in that the hammers are attached to the shaft by means of a drum mounted on it, covering the outer sleeve of the primary processing unit. 3. The mill according to claim 1, characterized in that in the inner sleeve there is a screw attached to a rotating shaft. 4. The mill according to claim 1, characterized in that the calibration chamber is equipped with a grid separating two independent gatherings. 5. A method of grinding bulk materials, according to which the bulk material cut in the pre-processing unit is further destroyed with hammers in a grinding chamber, where, due to centrifugal force, the grinding products are sorted by density and windage parameters and by air flow from holes in the walls of a hollow rotating particles with the required parameters are transferred through the shaft through the window in the rear wall to the calibration chamber, and larger particles continue to grind until the required Settings.

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