EP2313199A2

EP2313199A2 - Apparatus and method for producing flour and/or semolina

Info

Publication number: EP2313199A2
Application number: EP09772511A
Authority: EP
Inventors: Arturo Bohm; Kurt Grauer; Urs DÜBENDORFER
Original assignee: Buehler AG
Current assignee: Buehler AG
Priority date: 2008-07-02
Filing date: 2009-07-02
Publication date: 2011-04-27
Anticipated expiration: 2029-07-02
Also published as: RU2498854C2; KR101821088B1; US20110186661A1; RU2011103519A; WO2010000811A2; WO2010000811A3; US10981177B2; JP5854835B2; US9067213B2; EP2313199B1; KR101678625B1; KR20160134878A; CN102076418B; BRPI0915366B1; KR20110038651A; CN102076418A; BRPI0915366A2; US20150321196A1; JP2011526538A

Abstract

The apparatus according to the invention relates to a grinding arrangement (1) for producing flour from cereal, the latter in particular being bread wheat, durum wheat, maize or buck wheat. The grinding arrangement is characterized by at least one grinding mechanism (2) which is designed in particular as a stock-bed roller mill (16). The grinding mechanism has at least one feed opening (3) and at least one dispensing opening (4). The grinding arrangement comprises at least one separating stage (5) for separating ground products into finer ground product and coarser ground product, and a return arrangement (8) for returning at least some of the coarser ground product into the feed opening of the grinding mechanism.

Description

Apparatus and method for producing flour and / or semolina

The present invention relates to the field of production of flour and / or semolina from cereals having the features of the preambles of the independent claims.

From EP 0 335 925 B1 a method and an apparatus for producing milled grain products such as e.g. Flour, semolina or haze known according to the principle of high milling. The material to be ground is mill-rolled here many times, preferably twelve times to twenty times, and repeatedly sieved. The material to be ground is thereby guided at least twice over double-roller grinding stages without screening between the individual stages of the double-grinding and then each sighted at the Doppelvermahlung.

These prior art devices and methods have the disadvantage that the material to be milled is strongly heated in the grinding arrangements during the grinding process. This is particularly disadvantageous in the milling of grain to flour, since the introduced into the grain heat the proteins present in the grain are changed or damaged. In particular, gluten is changed by the introduced heat, since this is thermolabile. Since gluten has a very large influence on the bread quality of a bread to be baked with the flour, changes in the gluten through the milling process lead to changes in the bread quality, which must be compensated for example in a bakery during the production process of a bread from the flour produced.

A further disadvantage of the previously known method and the device for producing flour from cereals is the compulsory use of several sequential grinding machines for flour milling. Position, because they are expensive and their operation is energetically complex. This use of multiple grinders also results in the need for large buildings for the mill, further increasing the cost of constructing a mill.

In addition, the previously known method and the device have the disadvantage that they require a high energy requirement for the production of flour and / or semolina from cereals. For example, in the prior art, at least 25 to 27 kWh / t, or even more than 33 kWh / t, are needed to produce flour of common fineness, i. common particle size.

From DE 27 08 053 a process for fine and ultrafine comminution of ores is disclosed by means of a Goodbettwalzenmühle, this comminution takes place under strong compressive stress, but limited to protect against oversized compressive stresses and pressure peaks.

It is therefore an object of the present invention to avoid the disadvantages of the known, in particular therefore to provide a device and a method with which flour from cereals with less heat input during the grinding process can be produced. A further object of the present invention is to provide a device and a method by which flour from cereals can be produced inexpensively and energetically.

These objects are achieved by an apparatus and a method according to the characterizing part of the independent claims. The device according to the invention relates to a grinding arrangement for producing flour from cereals, this being, in particular, bread wheat, durum wheat, maize or buckwheat. The grinding arrangement is characterized by at least one grinder, which is designed in particular as a good bed roller mill. The grinder has at least one supply opening and at least one discharge opening. The grinding arrangement comprises at least one separation stage for separating ground products into finer ground product and coarser ground product and a return arrangement for returning at least a portion of the coarser ground product into the feed opening of the grinder.

Bread wheat is also known as Triticum aevestivum and durum wheat as Triticum durum.

For the purposes of the application, rice is also understood as cereals.

Roll mills usually have two rollers rotating at different speeds, between which a nip and thus a grinding force is adjustable, is transported through the example, grain and thus ground. The freeness, ie the particle size of the mill product to be achieved, is determined primarily by the size of the nip. During the grinding process, the nip remains constant. A grain to be ground is fed into this roll mill. In order to grind grain with such a roll mill, the nip must be adjusted to the particle size of the grain. In such a milling, a lot of heat is introduced into the grain by the mechanical grinding process and the pressure in the nip, especially in small nip widths, so that the grain is strongly heated. Since the grain is fed into the roll mill, ie in particular as a single particle, the throughput at a small nip, so in particular especially in the final, so-called Feinmahlstufen, very small.

For the purposes of the present application, a good-bed roller mill is understood to mean a force-controlled roller mill. For example, mechanically biased springs or hydraulically coupled gas pressure accumulators are used to generate power. A pressure is applied to the rollers in the direction of the nip, so that a nip between these rollers, depending on the amount and the type of grain to be ground in the nip and the set pressure. For example, a gap of about 0.5% to 2% of a roll diameter may occur. The resulting grinding gap thus results in the collection of the grain, which is in particular friction-dependent, through the rollers. In this case, a part of the particles may be larger than the gap. Typically, however, the particles are smaller than the resulting gap. In the catchment area between the rolls, a good bed then results when the good bed roll mill is made up of an oversupply of grain, e.g. by means of a filled material shaft or funnel, this can feed. The comminution is based on a packed particle bed in the grinding gap. The setting of the grinding force is used to control the energy input at the mill. The energy input determines - depending on material and grain size - the production of finer ground product in the good bed and is set to an optimum range.

In particular, the throughput through a good bed roller mill, for example, depends on the speed of the rollers. In general, a higher speed leads to a higher throughput. For example, peripheral speeds of the rolls, ie, the speed on the surface which is in engagement with the grain during the grinding process, can range from 1 m / s to 1.5 m / s, in particular less than 1 m / s and especially less than 0.1 m / s. In general, smaller peripheral speeds are set for finer mill products.

If, for example, the introduction of grain into the high-bed roller mill is not sufficient for friction, so that so-called fluidization phenomena occur, then a compressor, e.g. a so-called compressor screw, are used, which promotes the grain in the nip, supporting, for example, to gravity.

The good bed roller mill is thus characterized by a variable nip during grinding, an adjustment of the pressure in the grinding gap and in that an increase in the grain volume in the nip leads to an enlargement of the grinding gap.

Advantageously, the rolls of the good bed roller mill rotate at a different speed. This leads to an increased shear of the grain in the nip and thereby to an improved grinding in bran and semolina.

By bran is meant in the sense of the application also a mixture of bran and shell parts of the grain.

Furthermore, a separation stage in the sense of the present invention is understood to mean an apparatus for separating cereals into different sizes, shapes or densities, wherein a separation can take place either on the basis of one of these parameters or due to any combination of these parameters. For example, a separation can only take place in different particle size of the ground grain. Thereupon, for example, a further separation into different densities of the particles of a Size range possible. For example, in a first step, the ground grain can be separated into particles with particle sizes of 280 μm to 560 μm and particles with particle sizes of 560 μm to 1120 μm. In a second separation step, for example, the particles from the size range from 280 .mu.m to 560 .mu.m can then be sorted according to the density and / or the shape of the particles, while the particles from the size range from 560 .mu.m to 1120 .mu.m are ground a second time.

For the purposes of the present application, a separation of a ground product into a finer ground product and a coarser ground product means a relative separation according to particle sizes of the ground product. For example, when separating a milled product into particles having particle sizes from 100 μm to 200 μm and from 200 μm to 300 μm, i. in two fractions, the milled product in the first size range, the finer milled product and in the second size range, the coarser milled product. A separation is also possible in two, three, four or more fractions.

The inventive grinding arrangement has the advantage that by returning at least part of the coarser ground product into the feed opening of the grinder by means of the return arrangement to a reduction in the number of necessary grinders to achieve a defined degree of grinding, ie a particle size to be achieved after the grinding process, leads, as the ground product is passed through the grinder again until the defined degree of grinding is reached. This leads to a more cost-effective grinding arrangement over the prior art, since the number of grinders and the size of the entire grinding arrangement are reduced. Another advantage of the grinding arrangement, especially when using a good bed roller mill, is the selective grinding of the grain in the grinder, ie the bran is less ground than the meal body, also called endosperm. In other words, the bran retains a larger particle size than the ground meal body, making it easier to separate in a separation step.

The recirculated ground product is mixed, for example, before re-grinding in the grinder with not yet ground grain, so that a throughput of the mixture of grain and recycled ground product is kept as constant as possible in the grinder. This can be achieved for example by a control mechanism for the not yet ground grain.

Preferably, in the grinding arrangement, a specific grinding force of the grinder is adjustable so that grain is heated during the grinding process by less than 30 ⁰ C compared to the temperature of the grain before the respective grinding. The grain to less than 15 ° C is preferred, more preferably less than 10 ⁰ C, and most preferably heated to less than 5 ° C.

For the purposes of the present application, the ratio between the pressure exerted on the rollers in the direction of the grain, i.e., the specific grinding force S, is. the pressing force F, roller diameter D and the effective, with the grain engaging roller length L according to the formula S = F / LD understood.

The adjustability of the specific grinding force of the grinder in such a way that the heating of the grain is limited by the grinding process has the advantage that the change or damage of the proteins, in particular of the gluten in the cereals is reduced. This leads to better reproducible properties of the flour prepared according to the present invention. In special applications, for example, even a cooling of the rollers, the grain or the rollers and the grain provide.

The specific grinding power is thus advantageously adjusted so that the desired grinding result is achieved, i. producing a high level of finer milled product without overheating the grain during the grinding process. This also achieves a reduction in the energy consumption of the grinding plant over the prior art, since the grain is heated less.

Preferably, a nip between two rollers of the grinder of the grinding arrangement is variable at a constant specific grinding force on the einbringbare in the nip grain.

It is also possible, the specific grinding power, e.g. depending on the particle size, the number of resulting particles or the heating of the grain by hand or by means of control or regulating device adjustable or regulated to make.

The exercise of a constant specific grinding force on grain in the nip has the advantage that the grain is ground under constant conditions, ie substantially constant heat input into the grain by the grinding process. This is achieved in that the nip between the two rolls of the grinder is variable so that, for example, as the amount of grain in the nip increases, it becomes larger and thus the specific one exerted on the grain Grinding power remains constant. In the case where the amount of grain in the nip is reduced, the nip also decreases and the specific grinding force applied to the grain remains constant.

However, it is also possible that as the nip increases, the specific grinding force increases in a defined manner. This is achieved in that, for example, when using a mechanically biased spring for generating force an enlargement of the nip leads to a further elongation of the spring and thus an increased specific grinding force is adjusted due to the spring characteristic of the spring. Since the throughput of grain is increased by the enlarged nip at the same time increasing the specific grinding force an energy input per grain quantity remains approximately constant, so that the grinding conditions remain constant here. When the size of the grinding gap is reduced, the specific grinding force decreases accordingly so that an energy input per quantity of cereal remains approximately constant.

Quite surprisingly, it has now been shown that despite the gentle grinding of the grain by limiting the heat input into the compacted grain in the nip, the starch cores, i. the main constituent of the endosperm, be damaged. This damage is particularly adjustable, for example by adjusting the specific grinding force or a conditioning of the grain.

Particularly preferably, the separation stage of the grinding arrangement is configured such that cereal having a density of less than ² g / cm ³ and in particular smaller 1.5 g / cm ³ into finer ground product and coarser ground product is separable. The milling products have while a density of less than ² g / cm ³ and in particular less than 1.5 g / cm ³ .

This has the advantage that the separation step is adapted to the separation of grain into finer and coarser ground product and thus a better separation according to the density of the ground product is made possible. This is possible, for example, in separation stages which achieve separation by means of air flows, in that the geometry of the separation stage and the air flow are adapted precisely to the density range of the material.

More preferably, a specific grinding force in the grinding arrangement is set to less than 3 N / mm ² . This specific grinding force is preferably less than 2 N / mm ² , more preferably between 1 N / mm ² and 2 N / mm ² and most preferably less than 1 N / mm ² .

This limitation of the specific grinding power has the advantage that the heat introduced into the grain is further reduced by the grinding process, so that damage or changes in the proteins, in particular gluten, is further reduced.

Most preferably, the separation stage of the grinding arrangement comprises at least one device from the list of the following devices: zigzag sifter, grit cleaning machines, plan sifter, turbo sifter, sizing sifter, cross-sifter. Preferably, the separation stage comprises two of these devices, and more preferably at least two of these devices.

Zigzag classifiers are known from the prior art, for example from GB 468 212 and DE 197 132 107 C2 or from the textbook "Principles and Newer Methods of Air Classification" by H. Rumpf and K. Leschonski (CIT 39 (1967) 21, 1261ff).

Griesflutzmaschinen are known from the prior art, for example according to DE 612 639 Cl, DE 34 10 573 Al or the textbook "Maschinenkunde for Müller" by A. W. Rohner (1986) and are available for example from Buehler AG.

Planifters which are designed as screening devices are also known from the prior art, for example from the textbook "Maschinenkunde für Müller" by A. W. Rohner (1986) and are produced, for example, by Bühler AG.

Turbosensors are also known from the prior art, for example from the textbook "Handbook of Process Engineering" by H. Schubert (Wiley-Verlag) and are offered for example by the company Hosokawa Alpine AG, Augsburg in the series Turboplex or Statoplex.

This construction of the separation stage comprising at least one of the above-described devices has the advantage that for each separation according to particle size, particle shape or density, the respectively suitable device, ie zigzag sifter, grime cleaning machine, planifier or turbo separator can be integrated into the separation stage. For example, for a two-stage separation, it is possible to separate first according to the particle size and then according to the density of the particles. For example, a plan sifter is used for the first separation step and, for example, a zigzag sifter or a moth cleaning machine for the second separation step. In this case, the cereal separator is first separated into finer and coarser ground product with the plan sifter, and then, for example, the finer ground product is separated by means of a zigzag separator into components of different density. separated, ie especially in semolina and bran. It is also possible that the plan sifter separates the grain into several fractions and these fractions, including the coarser ground product, are then each conveyed to a separate zigzag sifter in which they are separated according to the shape and / or the density.

For the purposes of the application, semolina ground wheat with a small amount of bran, i. essentially clean semolina, understood.

However, it is also possible in particular for one separation stage to comprise one plan sifter and two or at least two successively arranged zigzag sifters.

Preferably, the grinding arrangement on two grinders. In particular, the grinding arrangement has three grinders, particularly preferably four grinders and very particularly preferably at least four grinders.

This has the advantage that, for example, structurally identical grinders can be arranged sequentially one after the other and in each grinder the grinding power for the grinding result to be achieved is individually adjustable. Furthermore, it is also possible, for example, to combine grinders of different construction, that is to say a good bed roller mill and a roller mill with a constant nip.

Particularly preferably, the grinding arrangement has two separation stages. This milling arrangement preferably has three separation stages, particularly preferably four separation stages and very particularly preferably at least four separation stages. This has the advantage that, for example, if the grinding arrangement has multiple grinders, each of these grinders can be followed by a separation stage. Furthermore, it may be advantageous that two separation stages are arranged sequentially and each of these separation stages carries out a separation of the ground product according to different parameters.

Also very particularly preferred is a flow-based separation stage, in particular with air flows, as a partial recirculation or circulating-air separation stage (5), in particular comprising a zigzag detector (13).

This has the advantage that at least a portion of the air passing through the separation stage is used to separate the meal product, for example, according to the density, i. Separation after, for example semolina and bran, is returned to the separation stage. This leads to a reduction in the energy consumption of the separation stage, as this, inter alia, the air consumption of the separation stage is lowered.

In a further preferred embodiment, the grinding arrangement comprises at least one separation stage for the separate removal of bran from the finer ground product.

This has the advantage that the bran, for example, still contained in the finer ground product is removed, which is particularly advantageous for the production of white flour.

In an alternatively preferred embodiment, the grinder has at least one roller type according to the following list: smooth rollers, corrugated rollers, profile rollers. For example, profile rolls have a defined surface roughness. This has the advantage that the grinder can be adapted to the respective grain to be ground and the grinding result to be achieved. It is possible that the grinder has two smooth rolls, two corrugated rolls or even a combination of smooth, profile and corrugated rolls.

Preferably, at least one grinder of the grinding arrangement, a conditioning device is vorschaltbar and / or nachschaltbar. At least one of the following cereal parameters can be set with this conditioning device: temperature, moisture, particle size, percentage of bran.

This has the advantage that the grain before and / or after grinding in the grinder is conditioned so that an optimum grinding result for the particular application is achievable. For example, the conditioning device may be formed as a shot peeper, in which the grain is ground with a roller mill with a constant nip. In this case, a ground product of bran and endosperm is produced. In the conditioning stage, for example, in a first step, a part of the bran can be separated and thus the proportion of bran in the grain can be adjusted. By adjusting the grinder in the shot stage, the particle size of the grain can also be adjusted, which is then fed into the subsequent grinder.

The conditioning device may, for example, also contain a planer for separating different particle sizes or also a part of the bran. In addition, the conditioning device may also include a tempering for heating or cooling of the grain before the grinding process and a device for adjusting the moisture of the grain. The grinding plant preferably has at least one sensor for measuring the ash content, the moisture, the temperature and / or the particle size of the ground grain, in particular the finer ground product and / or the coarser ground product. However, it is also possible to measure the temperature and / or the humidity of the air flowing out of the separation stage, for example from the zigzag classifier, with this sensor. This at least one sensor is preferably contained in the separation stage.

This has, inter alia, the advantage that the ash content or else the moisture content of the separated ground product, i. of the finer milled product and / or the coarser milled product, for example, after separation in the separation step is measurable. The milled product can then be conditioned, for example in a conditioner, to an optimum moisture content for grinding.

Another advantage is the measurement of the temperature and / or the humidity of the effluent from the separation stage air. As a result of this measurement, it is now possible, for example, to regulate the separation stage, in particular the zigzag sifter, to optimum conditions, i. optimal flow conditions for optimal separation, in the separation stage.

In particular, this is a near-infrared spectrometer, i. NIR spectrometer, and / or a color sensor. The color sensor is particularly suitable for measuring the ash content of the meal product. The NIR spectrometer is particularly suitable for measuring the moisture content of the ground product and / or the air.

A further aspect of the invention is directed to a process for producing flour from cereals, preferably from bread dough. zen, durum wheat, corn or buckwheat. This process is carried out in particular with a grinding arrangement as described above. In one process step, the milling of the grain takes place in a grinder, which is in particular a good bed of wheat mill. This grinder has at least one supply opening and at least one discharge opening. The milling of the cereal is carried out in particular with a specific grinding force such that the grain heats up during the grinding process by less than 30 ⁰ C compared to the temperature of the grain before the respective grinding. Preferably, the cereal is ground with such a specific grinding power so that the grain during the grinding process by less than 15 ° C, more preferably less than 10 ⁰ C and most preferably by less than 5 ° C compared to the temperature of the cereal before heated the respective grinding. The cereal is in particular preferably ground with a specific grinding force of less than 3 N / mm ² , preferably less than 2 N / mm ² , more preferably between 1 N / mm ² and 2 N / mm ² and very particularly preferably less than 1 N / mm ² , In a further method step, the ground grain is conveyed by means of a conveyor arrangement in a separation stage. In a further step, the separation of the ground grain in the separation stage into finer ground product and coarser ground product. In particular, cereals having a density of less than 2 g / cm ³ , in particular less than 1.5 g / cm, are separated into finer ground product and coarser ground product, the ground products having a density of less than 2 g / cm ³ , in particular less than 1.5 g / cm. In a next step, at least a part of the coarser ground product is returned to the feed opening of the grinder by means of the return arrangement. Furthermore, finer ground product is removed from the separation stage. This method is preferably carried out with the device described above and thus has all the advantages of the device described above.

On the one hand, it is preferred to set starch damage to the grain by selecting the specific grinding force when grinding in the grinder. On the other hand, the heat input into the grain is limited by this setting of the specific grinding force.

Under starch damage to the grain is understood in the sense of the application damage to the starch core in the endosperm, so that this example, easier to absorb water or is more accessible to enzymes.

This adjustability of starch damage to the grain by selecting the specific grinding power has the advantage that the starch damage of the grain is adaptable to the respective market needs. For example, a strong starch damage is needed in breadmaking in England because high water absorption of the flour is required in breadmaking in England. In Asia, however, a small starch damage is required, so that the flour absorbs little water, since many products are sold in Asia in a dried state and thus after the manufacturing process of the product by starch damage increasingly absorbed water must be removed, which is energetically complex and thus is expensive.

Particularly preferably, the grain is ground by means of two passes through the grinder at least 90% in finer ground product. In particular, the cereals by means of three passes, more preferably by means of four passes and very particularly preferably milled by at least four passes through the grinder at least 90% in finer ground product.

This has the advantage that if the fraction of finer milled product with fewer passes is achieved, the throughput through the muller is increased, but a higher specific mulling force is required. This leads to a stronger heating of the grain during the grinding and to a greater starch damage to the grain. If the grinding plant is set to require several passes through the grinder to achieve 90% finer milled product, then the throughput will be reduced by the same milling plant, but the specific grinding power will be lower for the same crop to be processed. As a result, less starch damage to the grain is achieved as well as less heating of the grain during the grinding process.

Very particular preference is given to essentially separating bran from the vegetable ground product in the separation stage in one process step.

Particularly preferably, the separation stage is followed by a further grinder for further grinding of the finer meal product.

This has the advantage that after the separation of a finer grinding product, this can be ground in a separate grinder for the production of, for example, special flours.

Further particularly preferred is the first separation stage downstream of a further separation stage for further separation of the finer meal product. This has the advantage that each separation stage can be adjusted to the specific separation result. For example, the separation stages may have different separating powers with regard to the density of the particles to be separated.

More preferably, at least one grinder downstream of a dissolver for the dissolution of the grain after grinding in the grinder. This has the advantage that with a possible compression of the grain in the grinder, the ground product is dissolved by the resolver into individual particles and thus a separation into finer and coarser ground product in the separation stage is made possible.

As a dissolver, so-called impact dissolvers are preferably used in practice. But there are also known to the expert drum, agitators or so-called Attritionsmühlen or friction mills.

Most preferably, at least one of the following parameters of the grain is adjusted in a conditioning device before and / or after grinding: temperature, moisture, particle size, proportion of bran.

In particular, the conditioning device is designed as a scraping stage.

An additional aspect of the present invention is directed to a zigzag sizer which is particularly suitable for carrying out the method as described above. The zigzag sifter is designed in such a way that cereal having a density of less than 2 g / cm ³ and in particular less than 1.5 g / cm ^{3 can be separated} into finer ground product and coarser ground product. The milling Products have a density of less than 2 g / cm ³ and in particular less than 1.5 g / cm.

This zigzag sifter is preferably used in the grinding arrangement described above and thus has all the advantages of the zigzag sifter described above.

An additional alternative aspect of the invention is directed to a good bed roller mill which is particularly suitable for carrying out the method as described above.

This good bed roller mill is preferably used in the grinding arrangement described above and thus has all the advantages of this grinding arrangement described above.

Preferably, grain in the high-bed roller mill is grindable into finer ground product and coarser ground product. A specific grinding force is less than 3 N / mm ² , preferably less than 2 N / mm ² , more preferably between 1 N / mm ² and 2 N / mm ² and most preferably less than 1 N / mm ² .

Another aspect of the present invention is directed to the use of a good bed roller mill for making flours and / or semolina from cereals, especially bread wheat, durum wheat, corn or buckwheat.

The good bed roller mill is characterized by a variable nip during grinding, an adjustment of the pressure in the grinding gap and in that an increase in the grain volume in the nip leads to an increase in the grinding gap.

Another alternative aspect of the invention is directed to the use of a zigzag separator for separating cereals, preferably bread wheat, durum wheat, corn or buckwheat. The separation of grain takes place after a grinding process in a grinder into finer ground product and coarser ground product.

Preferably, cereals with a density of less than 2 g / cm, in particular less than 1.5 g / cm ³ , are separated into finer ground product and coarser ground product. The milling products have a density of less than 2 g / cm ³ , in particular less than 1.5 g / cm ³ .

The zigzag sifter is particularly preferably used for separating bran from a finer ground product and / or coarser ground product.

The invention will be explained in more detail below with reference to embodiments for better understanding.

Figure 1: Schematic representation of an inventive

Device with good bed roller mill and a separator;

Figure 2: Schematic representation of an alternative inventive grinding arrangement with a roll mill and a separator;

FIG. 3: Schematic representation of a further alternative device according to the invention with a good bed roller mill and an alternative separating device;

FIG. 4: flow chart of a method according to the invention;

Figure 5: Schematic representation of an additional alternative device according to the invention with a Goodbettwalzenmühle and a dissolver; FIG. 6: flow chart of an alternative method according to the invention;

Figure 7: Schematic representation of a mill diagram with

Good bed roller mill, disintegrator, planifier, zigzag sizer and cyclone separator;

Figure 8: Schematic representation of another alternative device according to the invention with a roller mill with a constant gap and computer control of the grain supply;

Figure 9: Schematic representation of a good bed roller mill with grain in the nip.

Figure 10: Schematic representation of a zigzag sifter.

FIG. 11: Schematic representation of an impact dissolver.

FIG. 12: Schematic representation of a plan sifter.

FIG. 1 shows a schematic representation of a grinding arrangement 1 according to the invention.

The grinding arrangement has as a grinder on a Goodbettwalzenmühle 16, as shown for example in Figure 9. The good bed roller mill 16 has a feed opening 3 and a discharge opening 4 for the cereal 20. Furthermore, the grinding arrangement 1 has a separating device 5 which has a zigzag seal 13, for example according to FIG. 10, as well as a plan sifter 15, for example according to FIG. Ground grain 20, the coarser ground product 21, finer ground product 22 and bran 23 contains is transported by means of a conveyor assembly 9 of the bed of material rolls 16 in the separation stage 5. The rolls of the good bed roller mill 16, not shown here, here have a diameter of 250 mm. The conveyor assembly 9 is designed as a downpipe, so that the ground grain 20 is conveyed by gravity into the separation stage 5. The separation stage 5 has an inlet opening 6 for receiving the coarser meal product 21, the finer meal product 22 and the bran 23. Furthermore, the separation stage 5 has three outlet openings 7, through which in each case the coarser ground product 21, the finer ground product 22 and the bran 23 are separately dischargeable. The coarser ground product 21 is returned to the grinder 2 by means of the return arrangement 8. As a return arrangement, a chain conveyor is used here. Alternatively, however, the use of a bucket elevator as a return arrangement is possible.

Cereal 20 is transported through the feed opening 3 into the good bed roller mill 16, the cereal 20 being ground in the good bed roller mill 16 into coarser ground product 21, finer ground product 22 and bran 23. For this purpose, a maximum specific grinding force of 1 N / mm ^{2 is set} in the good bed roller mill 16, which typically forms a nip of between 1.25 mm and 5 mm, depending on the amount of grain 20 fed. The ground product is transported via the discharge opening 4 and the conveyor assembly 9 and through the inlet opening 6 in the separation stage 5. In the separation stage 5, the ground product is sorted by size into coarser ground product 21 and a mixture of finer ground product 22 and bran 23 in a first step. For this purpose, the plansifter 15 is used. The coarser ground product 21 is transported through one of the outlet openings 7 in the return assembly 8 and returned to the grinder 2 for re-grinding. The mixture of finer ground product 22 and bran 23 located in the separation stage 5 is separated into bran 23 and finer ground product 22 by means of a zigzag sifter. The finer ground product 22 is discharged via the lateral outlet opening 7 and the bran 23 via the upper outlet opening 7.

The good bed roller mills here have rolls with a roll diameter of 250 mm with a length of 44 mm. On the rollers, a force of 22 kN is exercised. The grinding is carried out with a specific grinding force of 2 N / mm ² with a nip of a gap thickness of 2 mm. A flour yield in ground product here is 12.5%, with about 5.3% bran being separated with a zigzag sifter. The specific energy consumption at the mill is only 1.6 kWh / t, corresponding to approximately 12.8 kWh / t are needed for the production of finished flour.

The grain fed to the circuit here has an ash content of 0.52%, the ash content of the flour produced being 0.47%.

FIG. 2 shows an alternative schematic representation of a grinding arrangement 1 according to the invention. The same reference symbols in FIGS. 1 and 2 denote the same components here.

The grinding arrangement 1 according to the figure has, in contrast to the grinding arrangement, a grinder 2 with two rollers 10, which are spaced at a fixed distance s. The fixed distance s is adjustable and is adapted to the grain size and can be, for example, 1 mm.

In contrast to the method described in FIG. 1, there is no return of the coarser ground product 21 into the feedstock. drove opening 3 of the grinder 2 instead. For example, the coarser ground product 21 can be conveyed into another, not shown here grinder.

FIG. 3 shows a further alternative schematic representation of a grinding installation 1 according to the invention. The same reference symbols in FIG. 2 and FIG. 3 denote the same components here.

In contrast to the grinding plant 1 according to FIG. 2, the grinding plant 1 according to FIG. 3 has a separating device 5 which comprises a zigzag sifter 13 and a muck cleaning machine 14. In the separation stage 5, the mixture of coarser ground product 21, finer ground product 22 and bran 23 is separated by means of the zigzag detector 13 into coarser ground product 21 and a mixture of finer ground product 22 and bran 23. In a second step, the finer ground product 22 is separated from the bran 23 in the grime cleaning machine 14.

The method for grinding the cereal 20 and for separating the ground product from coarser ground product 21, finer ground product 22 and bran 23 is otherwise substantially as described in Figure 1.

FIG. 4 shows a flowchart of a method according to the invention. Cereal 20 is transported to a conditioning device 11 which contains a shot stage and there pre-ground into a mixture of bran 23 and semolina (21; 22). In addition, the grain is tempered in the conditioning device 11 to a temperature of 20 ⁰ C. After this conditioning, the conditioned grain 20 is conveyed to a high bed mill 16 and further ground, where it is mixed prior to milling with coarser ground product 21 that is recycled. The temperature during grinding increases by less than 5 ° C. In other words, the temperature of the conditioned grain 20, which has a temperature of about 20 ⁰ C prior to grinding, even after mixing with the recirculated coarser grind product 21 is not heated above 25 ° C during the grinding process in the high-bed roller mill 16. After grinding in the high-bed roller mill 16, the ground product is conveyed to a separating device 5 which comprises a planifter 15 and a zigzag classifier 13. In this separation stage 5, therefore, the ground product is separated into coarser ground product 21, finer ground product 22 and bran 23 and discharged separately from the separator 5.

It is also possible that the grain is cooled between the grinding stages or even a cooling of the rollers takes place itself. The combination of both cooling options is also possible.

FIG. 5 shows an additional alternative schematic representation of a grinding arrangement 1 according to the invention. Cereal 20 is conveyed into a good bed roller mill 16 and ground therein. The grinding process compacts the meal so that it is conveyed into a dissolver 12 before separation into planifier 15 into individual particle sizes. The dissolver 12 is designed here as an impact dissolver as shown in FIG. In this dissolver 12, the compacted ground product is essentially dissolved into the individual particles and then conveyed into a planifter 15 according to FIG. This plansifter 15 separates the ground product into coarser ground product 21 and finer ground product 22. The coarser ground product 21 is conveyed by means of the return arrangement 8 to the high-pressure bed mill. Finer ground product 22 is removed from the grinding arrangement 1. As a return arrangement is here Bucket elevator used. Alternatively, however, the use of a chain conveyor as a return arrangement is possible.

FIG. 6 shows a flow chart of an alternative method according to the invention for the production of flour 24. Cereal 20 is conveyed into a good bed roller mill 16 according to FIG. 9 and ground there. Subsequently, the ground grain 20 is conveyed to a planifter 15 according to FIG 12 and separated there into coarser ground product 21 and a mixture of finer ground product 22 and bran 23. The coarser ground product 21 is returned to the high pressure bed mill 16 for re-grinding. The mixture of finer ground product 22 and bran 23 is ground again in another bed of fine-bed roller 16. The ground product is then conveyed to a grinder 14 from Bühler AG (article number: MQRF-30/200) and there separated into coarser ground product 21, bran 23 and flour 24. The coarser ground product 21, which was separated as a finer ground product 22 after the first grinding stage, is thereby conveyed back to the good bed roller mill 16 for re-grinding.

FIG. 7 shows a diagrammatic representation of a mill diagram according to the invention. Cereal 20 is conveyed to a comminution mill 16 according to FIG. 9 for grinding and conveyed after grinding into a dissolver 12, which is designed here as an impact dissolver according to FIG. Subsequently, the ground product is conveyed to a further bed of good-quality roller mill 16 and ground again there. Subsequently, the ground product is conveyed into a plan view 15 according to FIG. 12, which separates the ground product into four fractions, each of which has particles in a defined size range. Each of these four fractions is transported into a separate zigzag classifier 13 according to FIG. 10, in which the bran is removed from the ground product. The remaining ground product is then placed in another bed of material. Grind roller mill 16, fed to a further dissolver 12 and then separated in a further Plansichter 15 in at least two, three, four or even five fractions. These can be ground again in high-bed roller mills 16 or else be conveyed in zig-zag sifter 13 for the separation of bran. In addition, the mill diagram includes cyclone separator 18 for further separating bran from an air stream of a zigzag sifter 18.

FIG. 8 shows an additional schematic representation of a grinding installation 1 according to the invention. The same reference symbols in FIG. 1 and FIG. 8 denote the same components here.

This grinding plant essentially corresponds to the grinding plant according to FIG. 1 and additionally has a sensor 31 for measuring the force which is exerted on the rolls 10 by the grain 20 in the nip W with the gap thickness s and a compressor 19 on. The sensor 31 is connected to a control device 30 for transmitting the measured forces to this control device 30. The control device 30 is further connected to the drive of the rollers 10 for adjusting the rotational speed of the rollers. In order to avoid overheating of the grain 20 by the grinding process, the force exerted on the rolls 10 by the amount of grain 20 in the nip W is measured. Increases now the measured force on the rollers 10 by, for example, a higher supply of grain 20 from the compressor 19, so more heat is introduced by the grinding process in the grinder 2 in the grain 20, resulting in changes or damage to the proteins, in particular Gluten, in the grain can lead 20. By means of the measured force by the sensor 31, the rotational speed of the rollers can now be reduced by the control device 30 such that the measured force on the rollers 10 again reached a setpoint. Thus, it can be ensured that not too much heat is introduced into the grain 20 by the grinding process and also the grinder 2 is not damaged.

The further process for producing flour corresponds to the process already described in FIG.

FIG. 9 shows a schematic representation of a good bed roller mill 16 with two rollers 10. In the good bed roller mill 16, grain 20 is drawn in by the opposing rotation r of the two rollers 10, so that a good bed situation arises in the roller gap W. On the rollers 10 with a diameter D of 250 mm and a length of 1000 mm, a force F of 300 kN is exerted, so that a specific grinding force of 1.2 N / mm ^{2 is} achieved. The ground grain 20 contains coarser ground product 21, finer ground product 22 and bran 23 ground. This ground product is compacted by grinding in the high-grade bed mill 16, so that it is to be dissolved into individual particles in a dissolver such as, for example, according to FIG. 11 before being separated in a separation stage not shown here.

Figure 10 shows a zigzag sifter 13 having an inlet 41 for a mixture of finer milled product 22 and bran 23 to be separated. A stream of air 40 is directed along the axis of the zigzag sifter and adjusted so that the bran 23 has a lower density than the finer milled product 22, is blown out through the outlet 42. The heavier ground product 22 falls in the zigzag classifier 13 so that it is conveyed out of the zigzag classifier 13 by the semen discharge. The so-called upward flow velocity of the air flow 40 is here in the range of 0.7 m / s to 2.5 m / s depending on the material to be separated. FIG. 11 shows an impact dissolver 15 with an impingement dissipator 51, rotors 51 and an impingement dissolver outlet 52. Compacted grain 53 is conveyed into the impingement dissolver 15, where it encounters the rotors 51, which dissolve the compacted grain inter alia by the impact, so that grain 54 substantially dissolved into individual particles is formed. This resolution can take place in several stages by successively connected rotors 51, for example two to six, wherein here two rotors 51 are shown, which are mounted on a shaft 55. The rotors 51 have a shape such that the grain is conveyed to the impact dissolver outlet 52.

Figure 12 shows a plan sifter 15 with a coarse screen 61, a middle screen 62 and a fine screen 63. Ground grain 20 containing coarser ground product, finer milled product 22 and bran 23 is conveyed into plan planer 15 so that the milled grain can be separated into several fractions of different sizes. The coarse screen 61 has a mesh size of the screen of 1120 μm, the middle screen 62 a mesh size of the screen of 560 μm, and the fine screen 63 a mesh size of the screen of 280 μm. The ground grain 20 is thus separated into three fractions, the first fraction having a size range of 1160 microns to 560 microns, the second fraction has a size range of less than 560 microns to 280 microns and the third fraction a size range of less than 280 microns. The first fraction and the second fraction are here classified as a coarser ground product 21 and contain bran 23. These two fractions are then promoted according to Figure 1, for example, in a high-pressure roller mill. The third fraction, which contains finer ground product 22 and bran 23, according to FIG. 1, for example, is conveyed into a zigzag classifier according to FIG. 10 for separating the bran.

Claims

claims

1. Grinding arrangement (1) for producing flour and / or semolina from cereals (20), in particular bread wheat, durum wheat, corn or buckwheat, characterized by at least one grinder (2), in particular a Gutbettwalzenmühle (16), with at least one Feed opening (3) and at least one discharge opening (4), at least one separation stage (5) for separating meal products (21; 22) into finer ground product (22) and coarser ground product (21) and a return arrangement (8) for returning at least one part of the coarser ground product (21) into the feed opening (3) of the grinder (2).

2. grinding arrangement (1) according to claim 1, characterized in that a specific grinding force of the grinder (2) is adjustable so that grain (20) during the grinding process by less than 30 ⁰ C, preferably by less than 15 ° C. , more preferably heated to less than 10 ⁰ C and most preferably by less than 5 ° C compared to the temperature of the cereal (20) before the respective grinding.

3. grinding arrangement (1) according to claim 1 or 2, characterized in that a nip (W) between two rollers (10) of the grinder (2) is variable at a constant specific grinding force in the nip (W) einbringbares grain ( 20).

4. grinding arrangement (1) according to one of claims 1 to 3, characterized in that the separation stage (5) is designed such that cereal (20) having a density of less than 2 g / cm ³ , in particular less than 1.5 g / cm ³ , in finer Ground product (22) and coarser ground product (21) is separable and the ground products (21; 22) have a density of less than 2 g / cm, in particular less than 1.5 g / cm.

5. grinding arrangement (1) according to one of claims 1 to 4, characterized in that a specific grinding force is less than 3 N / mm ² , preferably less than 2 N / mm ² , more preferably between 1 N / mm ² and 2 N. / mm ² and most preferably less than 1 N / mm ² , in the grinder (2) is set.

6. grinding arrangement (1) according to one of claims 1 to 5, characterized in that the separating step (5) one, preferably two, more preferably at least two devices from the list of the following devices comprises: zigzag sifter (13), Griesling machine ( 14), plansifter (15), turbo heaters (17).

7. grinding arrangement (1) according to one of claims 1 to 6, characterized in that the grinding arrangement (1) two grinders (2), preferably three grinders (2), more preferably four grinders (2) and very particularly preferably at least four grinders (2).

8. grinding arrangement (1) according to one of claims 1 to 7, characterized in that the grinding arrangement (1) has two separation stages (5), preferably three separation stages (5), more preferably four separation stages (5) and very particularly preferably has at least four separation stages (5).

9. grinding arrangement (1) according to one of claims 6 to 8, characterized in that a flow-based separation stage (5), in particular with air flows, as a partial air or circulating air separation stage (5), in particular containing a Zigzag sifter (13), is formed.

10. grinding arrangement (1) according to one of claims 1 to 9, characterized by at least one separation stage (5) for the separate removal of bran (23) from the finer ground product (22).

11. grinding arrangement (1) according to one of claims 1 to 10, characterized in that the grinder (2) comprises at least one roller type from the list of the following types of rollers: smooth rollers, corrugated rollers, profile rollers.

12. grinding arrangement (1) according to one of claims 1 to 11, characterized in that at least one grinder (2) a conditioning device (11) is vorschaltbar and / or nachschaltbar for setting at least one of the following parameters of the cereal (20): Temperature, humidity, particle size, percentage of bran (23).

13. A method for producing flour from cereals (20), preferably from bread wheat, durum wheat, corn or buckwheat, and in particular with a grinding arrangement (1) according to one of claims 1 to 12, characterized by the following steps:

Grinding the cereal (20) in a grinder (2), in particular a good bed roller mill (16), with at least one feed opening (3) and at least one discharge opening (4), in particular with a specific grinding force such that the cereal (20) during the milling process by less than 30 ⁰ C, preferably by less than 15 ° C, more preferably by less than 10 ⁰ C and most preferably by less than 5 ° C warmed to the temperature of the cereal (20) before the respective Milling, in particular preferably with a specific grinding force of less than 3 N / mm ² , preferably less than 2 N / mm ² , more preferably between 1 N / mm ² and 2 N / mm ² and most preferably less than 1 N / mm ² ;

- conveying the ground grain (20) by means of a conveyor assembly (9) in a separation stage (5);

- Separation of the ground cereal (20) in the separation stage (5) in finer ground product (22) and coarser ground product (21), in particular that cereal (20) having a density of less than 2 g / cm, in particular less than 1.5 g / cm ³ , in finer ground product (22) and coarser ground product (21) is separated and the ground products (21; 22) have a density of less than 2 g / cm ³ , in particular less than 1.5 g / cm ³ ;

- Returning at least a portion of the coarser meal product (21) by means of return assembly (8) in the feed opening (3) of the grinder (2);

- Removal of the finer milled product (22) from the separation stage (5).

14. The method according to claim 13, characterized in that by selecting the specific grinding force during grinding in the grinder (2) starch damage to the grain (20) is set.

15. The method according to claim 13 or 14, characterized in that the grain (20) by means of two passes, preferably by means of three passes, more preferably by means of four passes and very particularly preferably by means of at least four passes through the grinder (2) at least 90% is ground into finer ground product (22).

16. The method according to any one of claims 13 to 15, characterized in that bran (23) from the cereal (20) in the separation stage (5) is substantially separated.

17. The method according to any one of claims 13 to 16, characterized in that the separation stage (5) is followed by a further grinder (2) for further grinding of the finer

Ground product (22).

18. The method according to any one of claims 13 to 17, characterized in that the first separation stage (5) is followed by a further separation stage (5) for further separation of the finer meal product (22).

19. The method according to any one of claims 13 to 18, characterized in that at least one grinder (2) a dissolver (12) is connected downstream of the dissolution of the grain (20) after grinding in the grinder (2).

20. The method according to any one of claims 13 to 19, characterized in that at least one of the following parameters of the cereal (20) in a conditioner (11), in particular a shot stage, before and / or after grinding is set: temperature, humidity, Particle size, percentage of bran (23).

21 zigzag sifter (13), in particular for carrying out the method according to one of claims 11 to 17, designed such that cereal (20) having a density of less than 2 g / cm, in particular less than 1.5 g / cm, in finer ground product (22 ) and coarser ground product (21) is separable and the ground products (21; 22) has a density of less than 2 g / cm, in particular less than 1.5 g / cm ³ .

22. Good bed roller mill (16), in particular for carrying out the method according to one of claims 13 to 20, that a specific grinding force of the good bed roller mill (16) is adjustable such that grain (20) during the grinding process by less than 30 ⁰ C, preferably to less than 15 ° C, more preferably by less than 10 ⁰ C, and is most preferably heated to less than 5 ° C above the temperature of the grain (20) in front of the respective grinding.

23. Good bed roller mill (16) according to claim 22, characterized in that grain (20) in finer ground product (22) and coarser ground product (21) is grindable and that a specific grinding force is less than 3 N / mm ² , preferably less than 2 N / mm ² , more preferably between 1 N / mm ² and 2 N / mm ² and most preferably less than 1 N / mm ² , in the grinder (2) is set.

24. Use of a good bed roller mill (16) for the production of flour and / or semolina from cereals (20), in particular from bread wheat, durum wheat, corn or buckwheat.

25. Use of a zigzag sifter (13) for separating cereals (20), preferably bread wheat, durum wheat, corn or buckwheat, after a grinding operation in a grinder (2) in finer ground product (22) and coarser ground product (21).

26. Use according to claim 22, characterized in that cereal (20) having a density of less than 2 g / cm ³ , in particular less than 1.5 g / cm, finer ground product (22) and coarser ground product (21) is separated and the meal - Products (21, 22) have a density of less than 2 g / cm ³ , in particular less than 1.5 g / cm.

27. Use according to claim 22 or 23 for separating bran (23) from a finer ground product (22) and / or coarser ground product (21).