EP2089167A1

EP2089167A1 - Classifier for classifying granular material

Info

Publication number: EP2089167A1
Application number: EP07819048A
Authority: EP
Inventors: Siegfried Strasser; Silke Liedtke; Jörg BINNER
Original assignee: KHD Humboldt Wedag AG
Current assignee: KHD Humboldt Wedag AG
Priority date: 2006-10-21
Filing date: 2007-10-17
Publication date: 2009-08-19
Also published as: DE102006049742A1; CN101528367A; WO2008046592A1

Abstract

In order to provide a classifier which can be inserted in a grinding circuit and whose grit discharge quantity recirculated to the mill is to be kept constant within certain limits without having to use a grit bunker arranged between the classifier and the mill, it is proposed according to the invention to design the classifier space above the coarse-material discharge opening (16) as an intermediate bunker for the classifier coarse material and to equip said bunker with level measurement means (19), and to control the filling level (20) between a bottom and a top limit value, and to arrange a controllable mechanical conveying member (22), which builds up the classifier coarse material (12) in the intermediate bunker, at the coarse-material discharge opening (16) of the classifier.

Description

Classifier for sifting grainy goods

DESCRIPTION

The invention relates to a classifier for sifting granular material, with a classifier housing with inlets and outlets for classifying air, Sichtgut, fines and coarse material.

A sifter of the type mentioned is usually turned on in a grinding circuit, where he used the ground of a mill such. As ores, cement raw material, cement clinker, etc., which is introduced at one point in the grinding circuit, separates into coarse material and fine material, which latter is discharged from the grinding circuit, while the coarse material is recirculated for further grinding for material feeding the mill.

In such continuously operated Mahlkreisläufen the amounts of recirculated Sichtergrobgutes, also called greek, subject to considerable fluctuations. Severe changes in recirculated classifier gobs can lead to irregularities in the operation of the mill, especially if this is a high pressure, high pressure roller crimping press, in whose nip the air filled grits must be drawn. The irregularities disturb the smoothness of the mill z. B. roller press and reduce the grinding efficiency.

It would be costly to first store the classifier seed in a bunker of its own and to regulate the contents of the bunker in a controlled manner via a dosing belt weigher of the mill. The problem will not solved by the known from DE-A 39 26 882 Mahlkreislauf with Gutbettzerkleinerungs roller press and dynamic rod basket sifter. Although the total amount of fresh goods and grass is measured there in the material feed chute of the roller press, no precaution is taken that the amount of classifier grain recirculated to the roller press can be subject to considerable fluctuations.

The invention has for its object to provide a run in a Mahlkreis- run sifter whose Grießeaustragsmenge recirculated to the mill is to be kept constant within certain limits without having to use a arranged between the sifter and the mill semolina bunker.

This object is achieved according to the invention with a separator with the features of claim 1. Advantageous embodiments of the invention are specified in the subclaims.

In the classifier according to the invention, a Greek bunker is integrated within it, by using a cavity, which is present in any case in the classifier, as a semolina bunker. This happens because the classifier space is formed above the grit or coarse material discharge opening as Sichtergrobgut intermediate bunker and used as such. Here, this Sichtergrobgut intermediate bunker is equipped with a level measurement, and the level height in the intermediate bunker is regulated between a lower and upper limit. At the coarse material discharge opening of the classifier, a controllable mechanical conveying member, which accumulates the inert material in the intermediate bunker, such as, for example, is disposed of. B. pressure screw, rotary valve, Trogket- thtenförderer etc. arranged. The level measurement in the Sichtergrobgut intermediate bunker is involved in the regulation of the grinding circuit, in which the separator according to the invention is used by a control action on the arranged on the Grobgutaustragsöffnung mechanical conveying member and / or on the amount of introduced into the grinding circuit to be ground fresh food done. In any case, according to the invention with relatively simple means strong fluctuations of recirculated semolina amounts in Mahlkreisläufen be avoided with mill and classifier.

For level measurement of Sichtergrobgutes in the intermediate bunker of the classifier can in this z. B. a layer height radar, and / or the entire classifier and thus the content of the integrated intermediate bunker can, for. B. be weighed via pressure cells.

Static air flow classifiers or dynamic rod basket classifiers often have an inner cone within the classifier housing for collecting the safety material to be separated in the classifying zone, via whose lower, conically tapered discharge end the inert material is discharged. In the separator according to the invention, the lower part of this inner cone of a static Luftstromsichters or a dynamic Stabkorbsichters is used as Sichtergrobgut- intermediate bunker and used.

The invention and its further features and advantages will be explained in more detail with reference to the embodiment schematically illustrated in the drawing.

The drawing shows in vertical section, partly in side view, an air classifier, which may be a static classifier or a dynamic classifier with the top of the classifier housing rotatably arranged rod basket.

According to the drawing embodiment, the classifier according to the invention has a conical surface, at least in its lower region. a truncated outer housing 10, in which a Sichtergrob- gut-collecting funnel or inner cone 11 is located, through the lower end of the collected Sichtergrobgut 12 is discharged. The granular feed material 13 to be viewed flows suspended in the visible air from bottom to top into the annular space between the outer housing 10 and the inner cone 11 of the classifier and flows through an optionally adjustable guide vane ring 14 from the outside in. Due to the flow deflection, the Suspension a coarse grain fraction 15 separated, which is transported by gravity on the inside of the funnel-shaped inner cone 11 down to the central coarse material discharge opening 16 of the classifier, while the remaining in the classifying air flow 17 fine grain fraction withdrawn via the central deflector 18 from the classifier zone and for the purpose of separation of the fine material In the drawing, not shown separator is supplied.

According to the invention, the space above the coarse material discharge opening 16 within the inner cone 11 is formed as an intermediate bunker for the Sichtergrobgut 12. This Sichtergrobgut intermediate bunker is equipped with a level measurement 19, z. B. with a layer height radar, which measures the current layer height 20 of the Sichtbrobgutes located in the intermediate bunker in an online measurement and keeps within certain limits by regulating operations described below. However, the amount of separator material 12 located in the intermediate bunker can also be determined by supporting the classifier housing 10 on pressure measuring cells 21 and thus weighing the sifter together with its contents. Finally, at the Grobgutaustragsöffnung 16 of acting as an intermediate bunker inner cone 11 a coarse material 12 in the intermediate bunker adjustable mechanical conveying member 22 arranged in the drawing embodiment, a pressure screw from the discharge opening 23 a regulated amount of Sichtergrobgut 12 to the mill such. B. Roller press, vertical mill / roller mill, ball mill, etc. of the grinding circuit is recirculated, in which the classifier is turned on.

To regulate the grinding circuit with the sensor according to the invention, the filling level 20 in the classifying material intermediate storage 1 1 is regulated within predetermined limits, whereby a regulating action is applied to the delivery rate of the mechanical conveying element 22 recirculating the classifying material 12 and / or to the amount of introduced into the grinding circuit Fresh good can be done.

From the drawing also shows that the sifter with the features according to the invention can not only be a static Luftstromsichter without moving parts, but also a dynamic rod basket sifter, in which a rotatably mounted, provided on the rotor circumference with Turboelementen rod basket with dashed lines vertical axis of rotation 24 is disposed concentrically within the vane ring 14 at the top of the classifier. Further, as indicated by the arrow 25, a portion of the first feedstock and / or a second feedstock may be loaded onto the sifter from above.

Claims

Classifier for sifting grainy goodsA NSPR Ü CHE

1. classifier for sifting grained goods, with a classifier housing (10) with inlets and outlets for classifying air, visual material, fine material and coarse material, characterized by the following features:

a) the classifier space above the coarse material discharge opening (16) is designed as Sichtergrobgut intermediate bunker;

b) the Sichtergrobgut intermediate bunker is equipped with a level measurement (19), and the level height (20) in

Intermediate bunker is regulated between a lower and upper limit;

c) at the Grobgutaustragsöffnung (16) of the classifier is a Sichtergrobgut (12) in the intermediate bunker accumulating controllable mechanical conveying member (22).

2. A separator according to claim 1, characterized in that the mechanical conveying member (22) for discharging the Sichtergrobgutes (12) from the intermediate bunker of the classifier is a pressure screw or a rotary feeder or a trough chain conveyor.

3. A separator according to claim 1, characterized in that for level measurement of the safety material in the intermediate bin bunker in this a layer height radar (19) is arranged and / or the classifier on pressure cells (21) is weighed.

4. A classifier according to claim 1, characterized in that the lower part of the inner cone (11) of a static air flow sensor or of a dynamic rod basket sifter is used as the classifier material intermediate bunker.

5. Classifier according to one or more of claims 1 to 4, characterized in that the classifier is integrated into a grinding circuit with a mill, wherein the coarse material discharge opening (16, 23) of the classifier is in contact with the crop of the mill.

6. A separator according to claim 5, characterized in that for controlling the grinding circuit with the integrated classifier the level (20) in the Sichtergrobgut- intermediate memory (11) of the classifier is controlled within predetermined limits, wherein a control intervention on the flow rate of the Sichtergrobgut (12 ) recirculating mechanical conveying member (22) and / or carried on the amount of introduced into the grinding circuit fresh material.