EP2785472A1

EP2785472A1 - Device for sifting granular material

Info

Publication number: EP2785472A1
Application number: EP12790561.0A
Authority: EP
Inventors: Harald Günter; Thomas HANSTEIN; Eberhard Neumann; Eggert De Weldige
Original assignee: Maschinenfabrik Koeppern GmbH and Co KG
Current assignee: Maschinenfabrik Koeppern GmbH and Co KG
Priority date: 2011-11-28
Filing date: 2012-11-23
Publication date: 2014-10-08
Anticipated expiration: 2032-11-23
Also published as: ES2592632T3; US9636712B2; DE102011055762A1; WO2013079416A1; EP2785472B1; DE102011055762B4; CN104039466A; FI2785472T4; US20140306044A1; EP2785472B2; DK2785472T4; IN2014KN01125A; DK2785472T3; CN104039466B

Abstract

The invention relates to a device (1) for sifting granular material into at least three fractions, comprising at least one static sifter (2) forming a first sifting stage and at least one dynamic sifter (3) forming a second sifting stage, wherein the static sifter (2) has several impact installations and conducting installations (8, 9) arranged one below the other in the manner of stairs in a sifter housing (4) having a first material inlet (5), a sifting gas inlet (6), and a coarse material outlet (7), wherein the dynamic sifter (3) is designed as a rod basket sifter having a rotary rod basket (12) and has a sifter housing (11) having at least one medium material outlet (17) and one fine material outlet (18). The static sifter (2) is directly connected laterally to the second sifter housing (11) of the dynamic sifter (3) by means of the sifter housing (4) of the static sifter, which sifter housing is arranged, for example, in the manner of a shaft and at an angle to the vertical, and the static shifter transitions into the second shifter housing. The rod basket (12) of the dynamic sifter (3) rotates about a vertical axis (14).

Description

Device for sifting granular material

Description:

The invention relates to an apparatus for sifting granular material into at least three fractions, comprising at least one static sifter forming a first sizing stage and at least one dynamic sifter forming a second sizing stage, the sifter in a sifter housing having at least a first material inlet, at least one sifter inlet and at least one Grobgutaustritt has a plurality of stair-like mutually arranged impact and Leiteinbauten, wherein the dynamic classifier is designed as a rod basket sifter with rotating rod basket and having a second classifier housing with at least one Mittelgutaustritt and a fine material outlet. In the grainy good to be seen, it may, for. For example, cement, cement-containing substances, cement raw material, limestone or slag but also to ores or the like. For the comminution of such granular materials in particular roller presses or good bed roller mills are used in practice. In this high-pressure crushing of the granular material to be crushed this in the gap between two press rolls (Gutbettzerkleinerung). In the course of comminution, agglomerates are formed, called slugs. Such good bed roller mills can be operated in a closed circuit with static and / or dynamic classifier. The good bed roller mill is then positioned below a sifter, for example, so that the coarse material fraction emerging from the sifter is (again) fed to the roller mill. The material emerging from the roller mill is in turn fed to the material inlet of the viewing device.

led, which is composed as a multi-stage device of a static classifier and a dynamic classifier. In the static classifier, a deagglomeration of the slugs takes place via the baffles and Leitinstallations, and at the same time the coarse material fraction is deposited and fed to the roll press. The "finer" material passes with the classifier gases into the dynamic classifier, where it is subjected to fine classification. The fines from this classifier are removed together with the classifying gas and collected in the following cyclones and / or filters as finished product. The weighted from the dynamic classifier middle fraction can, for. B. also be fed again to the roll press or another grinding stage. Such measures are known from the prior art (cf., for example, DE 43 37 215 A1).

A generic sighting device of the type described above is known z. B. from DE 42 23 762 B4. This classifier has in a housing a rotatably driven rod basket with distributed over the rotor circumference arranged turbo elements and with inlets and outlets for Sichtluft, Sichtgut, fines, medium and coarse material. The horizontally arranged bar basket is preceded by a shaft-like caution chamber at the same height at the same height, the top of a view of the separate air entry port for the Sichtgut, the side of the rod basket opposite arranged opening for the classifying air, below a discharge opening for a coarse grain fraction and two opposing, has between it a caution zone forming, for the Sichtluft permeable Schachtbegren- tion walls. These view-air-permeable shaft boundary walls of the caution chamber have obliquely downwards in the direction of the discharge opening of the coarse material fraction inclined inclined louvre-like baffles, which at the same time provide as baffle and Leiteinbauten for a deagglomeration of the scabs.

Incidentally, it has been proposed to provide roof-shaped installations in air classifiers, which are arranged in cascade such that the ridge edge of each installation lies approximately perpendicularly below the discharge edge of the surface of the installation disposed beyond that (see DE 1 002 600).

From WO 03/097241 A1 is also known a generic viewing device, wherein the dynamic classifier - as well as in DE 42 23 762 B4 - is equipped with a rod axis rotating about a horizontal axis. In order to minimize the problems of mechanical transport of circulating ground material is proposed in this prior art, to arrange the static cascade classifier below the nip of the roller press and above this roller press to arrange the indulgence, which should be designed in particular as a dynamic rod basket sifter. A disadvantage is the considerable height in this embodiment. The connecting line between the two classifiers increases investment and operating costs. An alternative embodiment of a multistage classifier with a compact design is known from US Pat. No. 7,854,406 B2. The viewing device consists of a plurality of concentric housings, wherein a rotating about a vertical axis rod basket is provided as a Nachsichtstufe. The precautionary stage is formed by a simple cyclone with the sight and the sighting gas supplied via a common supply line spirally connected to the classifier housing. A deagglomeration of the scapula is limited in the static vision level possible.

DE 10 2004 027 128 A1 discloses a device for sifting granular material into at least three grain fractions with a static sifter and a dynamic sifter, which are arranged rotationally symmetrically about a common axis in a common housing.

Finally, DE 10 2006 039 775 A1 discloses a classifying device in a special construction with a static cascade classifier and a further classifier as a classifier, wherein the cascade classifier has two packets each spaced above one another and concentrically arranged conical rings.

Incidentally, DD 253771 A1 describes an air classifier for classifying, in particular, fine-grained bulk materials in at least two fractions, consisting of a cylindrical upper housing part, followed by a semolina cone with semolina discharge at the bottom. The rod basket rotates about a vertical axis. Here, the distribution of goods in the viewing area of classifiers with baskets to be improved so that the selectivity is increased and the energy consumption, based on the final product, regardless of speed and shape of a spreading plate is lowered. For this purpose, an annular container with a fluidized-bed as dispersing device is provided, which is arranged above the Sichtgaseintritts- nozzle in the region of the rod basket inside or outside of the classifier housing and communicates with the viewing space via an annular gap and / or an annular channel. The known classifiers of the type described have basically proven themselves in practice, but they are capable of further development, in particular with regard to their visual efficiency.

The invention is therefore an object of the invention to provide a device for sifting granular material in at least three fractions of the type described above, which is characterized not only by a particularly compact design, but in particular by low investment and operating costs and higher visual efficiency. In particular, such a sifting device should enable economical operation of a grinding plant with at least one roller press with high visual efficiency.

To solve this problem, the invention teaches in a generic ago direction for sifting granular material in at least three fractions of a type initially described that

- The static sifter with a z. B. shaft-like and obliquely oriented to the vertical classifier housing is connected directly laterally to the separator housing of the dynamic classifier and passes into this and

- That the bar basket of the dynamic classifier rotates about a vertical axis.

The invention is initially based on the generally known knowledge that it is advantageous to combine a static classifier and a dynamic classifier in the embodiment as Stabkorbsichter together, as on the static classifier a first coarse material fraction can be spied out, so that the dynamic sifter with the relatively sensitive rotating components is not unnecessarily burdened with coarse material. According to the static and the dynamic classifier in a particularly efficient and compact design summarized by a rod basket with a vertical axis of rotation is used for a

and on the other hand, the static sifter is connected directly to the side of the dynamic sifter, wherein the static sifter, in terms of process technology, fulfills both the task of the agglomerate agglomeration and a first coarse separation. The static sifter and the dynamic sifter are consequently brought together close to each other, so that both sifters work energetically very efficiently and the static sifter can fulfill the task of sludge deagglomeration.

In combination with the connection according to the invention of the static classifier to the dynamic classifier, the use of the rod basket classifier rotating about a vertical axis is of particular importance. Because this configuration with "vertical" rod basket sifter is characterized by a uniform flow of the rod basket or rotor and thus by improved visual efficiency. The problems occurring in the prior art with "horizontally" arranged rod basket axes problems are avoided in the invention, so that an overall improved visual efficiency is realized.

According to a first embodiment, there is the possibility that the classifier of the static classifier opens in tangential or spiral orientation in the classifier of the dynamic classifier. Alternatively, in a second embodiment there is the possibility that the sifter housing of the static sifter merges in the radial direction into the sifter housing of the dynamic sifter. Finally, as an alternative, embodiments are also included in which the connection of the static separator lies between the tangential orientation and the radial orientation.

In any case, the sifter housing of the static sifter is always compactly connected laterally to the sifter housing of the dynamic sifter so that the static sifter housing merges into the dynamic sifter housing. Of the

Sifter according to the invention thus has housing areas which can be assigned to both the static classifier and the dynamic classifier as a transition between the static classifier and the dynamic classifier. For example, it is provided that the classifier housing of the dynamic classifier has an upper housing portion in which the rotating rod basket is arranged, and has a lower housing portion, in which z. B. a failure funnel is arranged for the middle goods, wherein the static separator is connected with its housing to the lower housing portion of the dynamic classifier and merges into this lower housing section. This lower housing section of the dynamic sifter thus forms the transitional area between static sifter and dynamic sifter. The housing of the dynamic classifier may preferably be cylindrical, so that the upper housing portion and / or the lower housing portion may be cylindrical. The lower housing section of the dynamic classifier then also has the function of a cyclone, which can influence both the function of the static classifier and the function of the dynamic classifier. Thus, this cyclone formed by the lower housing section can influence the effect of the static vision level. At the same time, however, one can also consider this cyclone as part of the dynamic classifier, since it forms a inflow channel for the vertical admission of the staff basket and since within this housing portion or cyclone also the failure funnel of the dynamic classifier can be arranged. This also makes it clear that according to the invention, the static classifier and the dynamic classifier are spatially and also functionally closely connected.

As described, the static sifter is preferably connected to the lower housing section of the dynamic sifter. Then the static sifter (in a side view) is usually positioned below the bar basket.

tioniert. Alternatively, however, it is within the scope of the invention to arrange the static classifier or the static classifier at the same height or at least in some areas at the same height as the rotating rod basket. Within the static sifter, not only is an initial separation of coarse material and medium, but also a slag disagglomeration can take place. The slide deagglomeration is realized with the help of integrated impact and guide fixtures in the static classifier. The baffle and Leiteinbauten can be formed in a conventional manner of mutually inclined baffles or baffles. In a preferred embodiment, these plates or sheets are adjustable in their inclination, z. B. pivotable about a horizontal axis or rotatable. Since the operation of the static classifier during operation - in contrast to a dynamic classifier - is influenced only limited, such a setting option is appropriate. It can be set the desired conditions of the static classifier, so that in particular the flow conditions can be optimized. Alternatively, the baffles and Leiteinbauten can also be formed by roof-like installations, as z. B. from DE 1 002 600 are known. The roof-like installations can optionally be displaced in the horizontal direction. In the static classifier, the task of puck agglomeration on the one hand and a first coarse material separation on the other hand are always combined.

While the (second) classifier housing of the dynamic classifier is generally cylindrical or at least partially cylindrical, the static classifier has a bay-like or box-like housing, which is preferably oriented obliquely to the vertical, so that also arranged inside the baffle and Leiteinbauten are arranged along a slope. The shaft-like housing has on the one hand the material inlet or

Material entries for the good to be seen and on the other hand, at least one Sichtgaseinlass on which z. B. Air is supplied. For this purpose, the shaft-like housing having a (lower) shaft wall, which at a predetermined angle α between 10 ° and 80 °, z. B. 40 ° to 60 ° oriented. The housing can thus be arranged (in the side view) as a whole obliquely to the vertical. The same applies to the inside of the housing staircase with each other arranged baffles and Leiteinbauten. Between these, the viewing zone of the first viewing stage is formed, which at a predetermined angle ß between 20 ° and 70 °, z. B. 20 ° to 40 ° oriented relative to the vertical. However, the invention also includes a shaft-like housing, which is not aligned obliquely to the vertical, but parallel to the vertical.

The Sichtgaseintritt can z. B. from at least one obliquely above the built-in structures arranged inlet opening are formed. Alternatively or additionally, there is the possibility that the sight gas inlet is formed by one or more openings arranged in the shaft wall. These openings can z. B. be closed by flaps, so that can be varied by opening and closing the view gas supply. It is therefore within the scope of the invention that either an (upper) inlet opening of the type described is provided or that openings are provided in the shaft wall. Preferably, however, a combination of these measures is realized, so that then both at least one obliquely arranged above the internals inlet opening and one or more arranged in the shaft wall openings are provided, said openings optionally z. B. are closed by flaps. It is then possible to work with "variable" air supply and consequently an air flow control. It is expedient if the individual flaps individually, in groups and / or to open and close together, being particularly preferred by

the adjustment of the openings a variable and targeted adjustment is possible. Flaps means in the context of the invention generally means for opening and closing the openings and in particular for adjusting the air passage rate. Appropriate air flow control offers the possibility of further increasing the visual efficiency.

Furthermore, optionally or additionally, there is the possibility that the sight gas inlet is formed by a region of the sifter housing which is free of the chute wall. In this embodiment, can be dispensed with the shaft wall, so that then worked with open flow.

Of particular importance in the context of the invention, the combination of the side, z. B. tangentially or spirally connected first classifier housing with the arranged in a vertical orientation rod basket. The direction of rotation of the bar basket can be oriented with or against the tangential or spiral connection direction of the static separator housing.

The dynamic sifter is particularly preferred in the upper part, z. B. in the upper housing section with one or more other material entries see. This is particularly useful when the sifter is integrated into a multi-stage grinding plant, because then the ground good of a second stage can be fed to this sighting over this (second) material inlet. It may be z. B. to the Austragsgut a second crushing device, for. B. a ball mill act. The integration of the classifier in a single or multi-stage grinding plant will be explained in more detail below.

It is basically within the scope of the invention that a single static separator in the inventive, z. B. tangential or spiral, Art

connected to the dynamic classifier. However, two or more static classifiers, each with a classifier housing, are preferably connected to the dynamic classifier, in particular in the case of large units. The precaution for prospecting a coarse material fraction and for deagglomerating the scoop can consequently be carried out in parallel in several stages of precaution, in which case the individual precautionary steps are applied in parallel to the same dynamic classifier. The connection of the plurality of static classifier takes place (in plan view) preferably symmetrical. So it is within the scope of the invention that the plurality of static classifier over the circumference "symmetrical" and therefore arranged equidistantly. The offset amounts to 360 n in relation to the circumference, where "n" means the number of static classifiers. Consequently, if two static classifiers are used, they are preferably connected in plan view at an angle of 180 ° to the dynamic classifier. If three static classifiers are used, these are preferably offset by an angle of about 120 °, and if four static classifiers are used, they are preferably offset by an angle of 90 °, and so on.

In addition to the impact and guide installations provided in the static classifier, it may be expedient to provide impact installations also in the area of the dynamic classifier, eg. B. within the classifier housing of the dynamic classifier, preferably in the lower housing portion, which can take over the function of a cyclone for the reasons explained. On the housing wall of this cyclone inside baffles can be connected, which can function as "stumbling edges" or "peeling edges". They should counteract the cyclone effect of this part of the classifier and thus reduce this cyclone effect. Because with the help of this wall-mounted internals that can be collected in the wall area

Material be brought back towards the center or axis, so that the visual function is optimized.

According to a further proposal, it is optionally provided that the classifier housing of the dynamic classifier is provided with one or more additional air supply lines which perform the function of an air bypass. It is then not only the air supply via the air inlet of the static classifier, but on the dynamic classifier additional air can be supplied. This then leads to the fact that the air supply is reduced in the range of the static classifier, so that in this way an optimized adjustment of the air duct is feasible. This additional air supply can, for. B. be realized in the upper housing portion of the classifier housing of the dynamic classifier. Finally, it is within the scope of the invention, optionally in the field of static classifier additional air distribution devices, eg. B. perforated plates o. The like., Provide. These can be arranged in the sifter housing of the static classifier in the flow direction in front of the baffles and Leitinstallations. They lead to a better air distribution over the entire height of the static classifier.

The separator device according to the invention can be used for the sifting of granular materials of various kinds, in particular for the screening of cement, cement raw materials, limestone and similar materials. Alternatively, however, the invention also includes the screening of ores or the like. The natural resources of such raw materials are sometimes largely exploited, so that the extraction moves into hard to reach regions without sufficient water resources. There, the separator according to the invention can be used particularly efficiently.

The invention also relates to a single-stage (Kreislaufmahlanlage) or multi-stage grinding plant for the crushing of granular material with - at least a first crushing device and

- At least one sorter device of the type described, wherein the material emerging from the first crushing material enters the viewing device via the first material inlet and wherein the from the coarse material outlet of the sifting device (or the static separator) exiting coarse material of the first crushing device is supplied, said The middle section or the middle fraction which also leaves the viewing device (or the dynamic classifier) is likewise fed to the first comminution device or alternatively also to a second comminuting device. Consequently, in addition to the first comminuting device, a second comminuting device is also preferably provided, so that an at least two-stage grinding system is then realized. The first crushing device may preferably be a good bed roller mill and thus a roller press. In the second crushing device may be, for. B. act a ball mill. The medium sized out of the sighting device (namely the second viewing step) can consequently be used for this second comminuting device, e.g. B. the ball mill, are fed, said this crushed with the second crushing device and then on the second material inlet turn the second viewing stage, namely the dynamic classifier, can be supplied. Thus, the coarse material being observed in the first stage of view is fed to the roller press, while the medium ("grit") is fed to the ball mill, the ball mill discharging material becoming the dynamic sifter and the discharged material of the ball mill

Roll press are led to the static vision stage. This overall results in a particularly energy-efficient comminution of the material, namely using the described multi-stage classifier, without the second crushing stage requires its own classifier.

Alternatively, however, a multi-level, z. B. two-stage grinding system can be realized, in which in addition to the separator according to the invention, a further, separate separator is provided. The middle fraction of the described first classifier according to the invention is in turn subjected to a second size reduction device, e.g. B. supplied to a ball mill. The Austragsmaterial this ball mill is then not - as described above - again the first classifier, but the second, separate classifier supplied with the emerging from this second classifier coarse material is again fed to the ball mill, while emerging from the second classifier fines as turn Product can be removed.

Finally, according to the invention, however, single-stage grinding plants are also encompassed, in which both the coarse material emerging from the sighting device according to the invention and the middle product of a first (single) comminution device, e.g. B. roller press, is fed and wherein the material emerging from this crushing material in turn enters via the material inlet into the viewing device according to the invention. Thus, a single-stage Kreislaufmahlanlage is realized. It is within the scope of the invention that the first crushing device, for. B. roller press, is arranged above the sifter means. However, the roll press is particularly preferably positioned below the classifying device. In the following the invention will be explained in more detail with reference to a drawing showing only one exemplary embodiment. Show it:

Fig. 1 is a partial vertical section through an inventive

Fig. 2 is a plan view of the lower part of the article according to

1 in a first embodiment,

Fig. 3 is a plan view of the lower part of the article according to

1 in a second embodiment,

Fig. 4 shows a modified embodiment of the article according to

1 (detail in the region of the lower part),

Fig. 5 is a plan view of the lower part of the article according to

4 and

Fig. 6 shows schematically a two-stage grinding plant with a classifying device according to the invention. The viewing device 1 shown in FIGS. 1 to 5 is used for sifting granular material, for. As cement, in at least three fractions. The device 1 is composed of a static classifier 2 and a dynamic classifier 3, which are combined in a particularly compact manner. The static separator 2 forms a first viewing stage, and the dynamic classifier 3 arranged downstream of the static classifier 2 in the direction of the visual medium flow forms a second visual stage.

The static classifier 2 has a classifier housing 4 with the first material inlet 5, the classifying gas inlet 6 and the coarse material outlet 7. Within the classifier housing 4

are several, stair-like arranged with each other baffle and Leiteinbauten 8, 9 are arranged. In the exemplary embodiment, these fixtures are designed as baffles 8, 9, which also take over the function of baffles for the static separator. In Fig. 1 it can be seen that there are two groups of mutually inclined baffle plates 8, 9, wherein these baffles 8, 9 about pivot axes 10 are adjustable, so that the inclination of the baffles 8, 9 is adjustable.

The second viewing stage is formed by the dynamic classifier 3, which has a classifier housing 11. This cylindrical classifier housing 1 1 has an upper (cylindrical) portion 1 1 a and a lower (cylindrical) portion 1 1 b. In the upper part 1 1 a of this classifier housing 1 1, a rotating rod basket 12 is arranged, which surrounds a set of vanes 13. These are stationary vanes, which are arranged at a fixed or adjustable angle of attack to the axis of rotation of the bar basket. The rod basket 12 rotates about a vertical axis 14. For this purpose, a drive 15 is connected to the rod basket 12. Below the bar basket 12 a failure cone 16 is connected within the second classifier housing 1 1, which in turn is connected to the middle goods outlet 17. To the upper part 1 1 a of the classifier housing 1 1 of the fine material outlet 18 is connected, via which the gas-fine material mixture is discharged. Furthermore, further material inlets 19 are connected to the upper housing part 1 1 a.

The starting material to be viewed is fed to the sighting device 1 via the first material inlet 5. About this passes the goods to be sighted consequently in the first viewing stage and consequently in the static classifier 2. By the gas inlet 3, the classifying gas, for. B. supplied air. It may be z. B. also act hot drying gases. The material to be sighted now falls on the system of baffle and guide plates 8, 9, whereby it is particularly suitable for the Desagglo-

The slugs and agglomerates produced during milling in a roller press come. In this case, the material is flowed through by the viewing medium with possible, simultaneous drying. The static separator operates as a cross-flow air classifier, so that the coarse material falls through the housing 2 in the lower failure cone 20 and is discharged from there via the coarse material discharge 7. This failure cone 20 is structurally connected to the lower part 1 1 b of the classifier housing 1 1 of the dynamic classifier 3.

The static sifter and the dynamic sifter are interconnected in a very compact manner so that the static sifter 2 merges into the dynamic sifter 3. Because the static separator is connected with its classifier 4 side of the sifter housing 1 1 of the dynamic classifier. In the exemplary embodiment, it can be seen that the classifier housing 4 of the static classifier 2 merges into the lower housing portion 11 b of the classifier housing 1 1, so that the housing portion 11 b of the classifier housing 1 1 is functionally partially on the one hand the static classifier and on the other hand the dynamic classifier can be assigned. It establishes the connection between the static classifier and the dynamic classifier, with the cylindrical lower housing portion 11b also fulfilling the function of a cyclone.

In any case, the selected from the static separator 2 fraction occurs together with the classifying gas in the dynamic classifier 3, namely in the upper portion 1 1 a of the classifier housing 1 1 and there in the area of the staff basket 12. Between this rotating rod basket 12 and the stator blades 13th it comes to the desired Feinsichtung. The "coarser" or middle portions reach via the inner failure funnel or failure cone 16 to the failure tube and thus Mittelgutaustritt 17 ("Grießausfallrohr"). This middle fraction is also called "grits". The fines will be together with

the gases discharged through the fines and gas outlet 18 from the classifier. About the additional material inlets 19 can be further material directly to the second stage of view perform. It may be z. B. to act, which consists of an additional crushing device, for. B. is fed to a ball mill. This will be discussed in more detail in connection with FIG. 6.

2 and 3 show that the static separator 2 according to the invention with a shaft-like and obliquely arranged to the vertical first Sichter housing 4 is connected directly to the second classifier housing 1 1 of the dynamic classifier 3, in tangential or spiral embodiment Orientation. FIG. 2 shows an embodiment with a spiral connection, while FIG. 3 shows an embodiment with a tangential connection.

It can be seen in the two embodiments that in each case two static classifier 2 are connected with two classifier housings 4 to the classifier housing 1 1 of the dynamic classifier 3. The dynamic classifier 3 is thus applied in parallel by two static classifiers 2. For this purpose, the two static classifier 2 are positioned offset in the exemplary embodiment by 180 °. The direction of rotation of the bar basket can correspond to the direction of connection of the tangential or spiral connection or can also be designed counter to this. The embodiment shown in FIGS. 4 and 5 substantially corresponds to the embodiment according to FIGS. 1 and 3. It differs geometrically in particular by the arrangement and configuration of the failure funnel 16 of the dynamic classifier, which in the embodiment according to FIGS 5 over the entire height of the lower portion 1 1 b of the

Classifier housing 1 1 and also over the entire height of the classifier housing 4 of the static classifier 2 extends. Apart from that, the embodiments according to FIGS. 1 to 3 on the one hand and FIGS. 4 and 5 on the other hand differ in their geometric design, in particular in the area of the static sensor and its guide elements. The basic structure and operation are identical.

The shaft-like first classifier housing, which is connected in a tangential or spiral orientation to the second classifier housing, is of particular importance. The figures show that this shaft-like first housing 4 or its (lower) shaft wall 21 is oriented at a predetermined angle α obliquely with respect to the vertical. In the exemplary embodiment, this angle α is about 40 ° to 60 °, z. B. about 50 °. Incidentally, it can be seen that the visual zone of the static classifier formed between the baffle plates 8, 9 which are arranged in the manner of a staircase below one another is oriented obliquely with respect to the vertical at a certain angle. In the embodiment, this angle ß is about 20 ° to 40 °, z. B. 25 °. This overall obliquely oriented housing 4 is according to the invention connected spirally or tangentially to the housing of the dynamic classifier.

The figures show an embodiment in which the static classifier, although connected laterally to the dynamic classifier, but is positioned spatially below the rotating rod basket. Optionally, however, embodiments can also be realized in which the static classifier is arranged (at least in some areas) at the same height as the rotating rod basket. The same applies to embodiments with multiple static separators.

Incidentally, in the illustrated embodiments, the air supply takes place in particular via the illustrated Sichtgaseintritt 6. Alternatively or additionally, additional Sichtgaseintritte be provided, which are formed in particular by arranged in the shaft wall 21 openings. This is not shown in the figures. Such openings may be made by suitable means, e.g. As valves, slides or the like to open and close, in particular by adjustable means a variable adjustment and thus air flow control is possible.

The arrangement of the baffle plates 8, 9 is shown in the figures only by way of example. It is indicated that the articulation points of the baffles 8, 9 need not lie on a common straight line, but may be arranged at a distance from each other. This is indicated in particular in Fig. 4. However, it is alternatively also within the scope of the invention that the articulation points of the baffles or baffles (approximately) are arranged on a straight line or are also toothed and thus formed interlocking. However, they can also - as shown in the figures - be carried out at a distance between the articulation points, wherein this distance is significantly larger in FIG. 4 than in FIG. 1. The vertical distance between the individual plates need not be the same, but can vary from plate to plate. The plates can also be set at different angles.

The multistage classifier 1 according to the invention can be particularly preferably integrated into a one-stage or multistage grinding plant, as shown by way of example in FIG. By way of example, a cement grinding plant is shown. In the center of the figure, the multi-level classifier 1 can be seen, which is composed of static classifier 2 and dynamic classifier 3. Below the sifter 1, a first crushing device 22 in the embodiment is shown as a roller press, and thus a good bed roller mill 22. Further

2, a second crushing device 23 is shown in the embodiment as a ball mill 23.

The illustrated two-stage grinding plant works as follows:

The starting material to be crushed is fed from one or more bunkers 24, z. B. on the transport devices 25, 26, which open via the material inlet 5 in the sighting device 1. There, in the manner already described, the sifting of the material into three fractions. The coarse material which has been emitted from the coarse material outlet 7 is fed again to the roll press 22. From there it passes via the transport devices 27 and 25, 26 again into the viewing device 1. The average material, that is to say the middle fraction, which is oriented from the second visual stage, is fed via the middle product outlet 17 and the transport device 28 to the ball mill 23. The grinding plant thus comprises the roller press 22 for the premilling of the material and the ball mill 23 for the post-milling of the material. The ball mill 23 is z. B. equipped with a material take-off 29, a dedusting filter 30 and a mill fan 31. The material emerging from the ball mill 23 is thus supplied via the transport means 29, 32, 33, with which it is brought to the dynamic classifier 3. There it passes through the material inlets 19 again in the second view stage.

The finest fraction is withdrawn from the sighting device, namely from the dynamic classifier 3 together with the gases through the fine material outlet 18 into the following separation cyclones 34. Here it is separated as a finished product of the gases, which are withdrawn with the fan 35 and partially fed back into the classifier 1 and partially or completely to a dedusting.

The illustrated two-stage grinding plant can be modified in an alternative embodiment. So z. B. the roller press 22 are placed in contrast to the arrangement shown above the classifying device 1. In this case, the fresh material to be ground is then first fed into the roll press, from which the pre-milled material is guided to the sifter device according to the invention. There, the material is again classified in the manner described in three fractions. This embodiment is not shown. Alternatively, it is also possible to integrate in the two-stage grinding a second, separate viewing device, so that the Austragsgut the ball mill is then not shown in the figures first viewing device, but a not shown, separate second viewing device is supplied. Alternatively, only with a single crushing device, z. As the roller press shown, are worked, so that is then dispensed with the additional ball mill. Then, the final grinding takes place in the roller press, the visual device according to the invention then form the roller press a "simple", "single-stage" Kreislaufmahlanlage. This is not shown in the figures. However, the multi-stage classifier according to the invention can be used equally for the different types of grinding equipment.

Claims

claims:

1 . Device (1) for sifting granular material into at least three fractions, comprising at least one static classifier (2) forming a first classifier and at least one dynamic classifier (3) forming a second classifier, the static classifier (2) being designed as a cross-section classifier and in a classifier housing (4) with at least one first material inlet (5), at least one Sichtgaseinlass (6) and at least one Grobgutaustritt (7) a plurality of stepped like each other arranged baffles and / or Leiteinbauten (8, 9), wherein the dynamic classifier (3) is designed as a rod basket sifter with a rotating rod basket (12) and a sifter housing (1 1) with at least one Mittelgutaustritt (17) and a fine material outlet (18), characterized in that the static sifter (2) with its classifier housing (4) immediately laterally connected to the classifier housing (1 1) of the dynamic classifier (3) and passes into this and that the bar basket (12) of the dynamic classifier (3) rotates about a vertical axis (14).

2. Device according to claim 1, characterized in that the classifier housing (4) of the static classifier (2) in a tangential or spiral orientation or in a radial orientation or an orientation between

a radial or tangential orientation in the classifier housing (1 1) of the dynamic classifier (3) passes.

3. Apparatus according to claim 1 or 2, characterized in that the classifier housing (1 1) of the dynamic classifier (3) has an upper housing portion (1 1 a), in which the rotating rod basket is arranged, and a lower housing portion (1 b), wherein the static separator (2) with its housing (4) to the lower housing portion (1 1 b) is connected and merges into these.

4. Device according to one of claims 1 to 3, characterized in that the baffle and / or Leiteinbauten of mutually inclined baffle and / or guide plates (8, 9) are formed.

5. Apparatus according to claim 4, characterized in that the inclination of the baffle and / or guide plates (8, 9) is adjustable.

6. Device according to one of claims 1 to 3, characterized in that the baffle and / or Leiteinbauten (8, 9) are formed by roof-like installations.

7. Apparatus according to claim 6, characterized in that the roof-like baffles are displaceable in the horizontal direction.

8. Device according to one of claims 1 to 7, characterized in that the z. B. shaft-like housing (4) or at least one shaft wall (21) of this housing of the static classifier (2) preferably obliquely to the vertical, z. B. at a predetermined angle (a) between 10 ° and 70 ° relative to the vertical, is oriented.

9. Device according to one of claims 1 to 8, characterized in that between the step-like with each other arranged baffle and / or Leiteinbauten (8, 9) formed viewing zone of the static classifier (2) at a predetermined angle (ß) between 10 ° and 70 ° to the vertical oriented.

10. Device according to one of claims 1 to 9, characterized in that the Sichtgaseintritt (6) of at least one obliquely above the internals (8, 9) arranged inlet opening is formed.

1 1. Device according to one of claims 1 to 10, characterized in that the Sichtgaseintritt (6) alternatively or additionally of several in the shaft wall (21) of the classifier (4) of the static classifier (2) arranged and optionally adjustable openings or of a shaft wall-free area this housing is formed.

12. Device according to one of claims 1 to 1 1, characterized in that in the classifier housing (3) of the static classifier (2) in the flow direction in front of the impact and / or Leiteinbauten (8, 9) air distribution devices, for. B. perforated plates are arranged.

13. Device according to one of claims 2 to 9, characterized in that the tangential or spiral connection in the direction of rotation or counter to the direction of rotation of the rod basket (12) is oriented.

14. Device according to one of claims 1 to 13, characterized in that the classifier housing (1 1) of the dynamic classifier (3) has at least one second material inlet (19).

15. Device according to one of claims 1 to 14, characterized in that the classifier housing (1 1) of the dynamic classifier (3) is at least partially cylindrical.

16. Device according to one of claims 1 to 15, characterized in that two or more static classifier (2), each with a classifier housing (4) are connected laterally to the dynamic classifier (3).

17. The apparatus according to claim 16, characterized in that the plurality of static classifier (2) are arranged over the circumference equidistant with an offset of 360 n, where n corresponds to the number of static classifier.

18. Device according to one of claims 1 to 17, characterized in that in the classifier housing (1 1) of the dynamic classifier (3), z. B. in the lower housing portion (1 1 b), additional baffle structures are arranged, which are preferably arranged on the inside of the housing wall.

19. Device according to one of claims 1 to 18, characterized in that the classifier housing (1 1) of the dynamic classifier (3) with one or more additional air supply lines (as a bypass) is provided, for. B. in the upper housing portion (1 1 a).

20. Grinding plant, in particular Kreislaufmahlanlage or multi-stage Mahl- anläge, for the comminution of granular material with at least a first crushing device (22) and with at least one viewing device (1) according to one of claims 1 to 19,

wherein the material emerging from the first crushing device (22) enters the sighting device via the first material inlet (5), the coarse material emerging from the coarse material outlet (7) of the static sifter (2) being fed to the first crushing device (22) and wherein the from the dynamic classifier (3) emerging middle goods of the first crushing device (22) or an additional second crushing device (23) is supplied.

21. Plant according to claim 20, comprising a second crushing device (23), wherein the medium emerging from the dynamic sifter (3) is fed wholly or partly to the second crushing device (23) and wherein the material leaving the second crushing device (23) enters via the second material (19) the dynamic classifier (3) or a separate, second viewing device, is supplied.

22. Plant according to claim 20 or 21, characterized in that the first crushing device (22) as a roller press and / or the second crushing device (23) is designed as a ball mill / are.