EP0492062A2 - Air separator - Google Patents

Abstract

An air separator is proposed, having a housing, at least one upper material feed device, at least one lower finished product discharge device and one fixed ring of blades provided within the housing, it being possible to feed separating air to the ring of blades through at least one air inlet connecting piece running tangentially on the housing. A rotationally driveable rotor is provided concentrically within the ring of blades and is formed from at least two rings of rotor blades arranged concentrically with respect to one another, a plurality of finished product discharge devices being provided in order to be able to achieve in this manner a plurality of finished product streams of different granule size distribution in one working process. The rings of rotor blades are preferably rigidly connected to one another. <IMAGE>

Description

The invention relates to a wind sifter for classifying dusty bulk materials, in particular lime, ground clinker, quartz powder, cement raw material or the like. With a housing, at least one material feed device, at least one finished product discharge device, a fixed blade ring provided inside the housing in its outer region as well as a rotor, including guide vanes with an essentially cylindrical cross-section, which is arranged so as to be rotatably drivable concentrically within the blade ring, visible air being able to be fed to the blade ring through at least one air inlet nozzle running tangentially on the housing.

From DE-PS 35 45 691 a device for classifying dusty bulk goods, in particular ground clinker, limestone or cement raw material by air classification is known, the material to be classified is fed via a material inlet to the cover plate of a cylindrical rotor with vertical rotor blades and a ring cylindrical Visible space is given up, which extends between the rotor and a fixed blade ring surrounding it at a distance, through which visible air is sucked in approximately tangentially from an external fan. Fine material is transported radially inward as a result of the flow conditions within the classifier and discharged through a central discharge pipe, while coarse material is removed from the classifier by means of a drain pipe provided in the outer peripheral region.

From DE-AS 25 56 382 a centrifugal air classifier with an essentially cylindrical visible space is known, into which the visible air and the visible material are introduced with a twist on the outer circumference, the coarse material being drawn off on the outer circumference of the visible space, and the visible air together are discharged with the fine material through a central, stationary suction pipe covering the axial extent of the visible space, the suction pipe having inlet openings distributed around its circumference.

Furthermore, US Pat. No. 1,746,686 shows an air classifier which has a housing in which two classifying devices arranged axially one above the other are arranged, by means of which a total of three fractions can be generated which are discharged in the region of the housing base. As a result of the superimposed viewing devices builds the housing axially relatively high, and the overall structure of the device is also considered to be expensive.

Furthermore, DE-OS 35 21 638 shows a scattering classifier, in particular for classifying cement, which contains a good task, a spreading plate with drive which distributes the good stream to a good veil, a classifying wheel, a classifying air supply opening and a coarse material and fine material discharge . The material flow feed and the fine material discharge are arranged in the classifier axis and for the coarse material discharge a conveyor channel is provided in a ring around the fine material discharge, the good veil through which the visible air flows is designed as a bell-shaped outer surface.

In the viewing gap of these air classifiers, which are also known as cross-flow classifiers (classifying air is supplied laterally or tangentially), there are uneven flow velocities in the tangential direction. This leads to turbulence at the classifier rotor, which can lead to an insufficient visual effect. It is also disadvantageous to note that this type of air classifier only includes the possibility of dividing the feed material into two sight streams, namely into the coarse material and the fine material component.

In some applications, e.g. in the cement industry, however, it can be advantageous to divide the feed material into three or more material flows with different grain size distributions.

The aim of the invention is to develop a wind sifter, as described, for example, in DE-PS 35 45 691, in such a way that the feed material can be divided into at least three material streams of different grain size distribution with optimized visibility efficiency, without significantly changing the vision concept , whereby it can be very useful to merge two or more material flows after the visual process.

This object is achieved according to the invention in that the rotor contains at least two concentrically arranged rotor blade rings including guide vanes, that below the rotor blade rings or the Guide vanes are provided several independent finished goods discharge devices, and that the semolina outside of the finished goods discharge devices are brought together and can be removed by a semolina discharge device.

Advantageous further developments of the subject matter of the invention can be found in the subclaims.

The finished product discharge device is divided into a first and a second finished product discharge when using two rotor blade rings, which are separated from each other by labyrinths on the one hand and on the other hand from the Graesse discharge, the first finished product discharge optionally being operated with or without air flow.

The finished product can either be discharged downwards, only upwards or - depending on the application - both upwards (air flow) and downwards. The respective selection is made dependent on the bulk material to be classified. The same applies to the selection or arrangement of the guide vanes. On the one hand, these can be rectilinear or slightly curved, and they can be of different lengths radially. As an alternative or in addition, round bars can also be used as guide elements. Depending on the material, it may it also makes sense to make the guide vanes at least partially radially so long that they connect at least two rotor blade rings to one another. However, this requirement only makes sense for rotor blade rings which are firmly connected to one another.

• das Aufgabegut wird in Produkt-Feingrieße und -Grobgrieße aufgeteilt, wobei die Grobgrieße der Klinkervorzerkleinerung und die Feingrieße einer Kugelmühle zugeführt werden können,
• das Aufgabegut kann in PZ 45, PZ 35 und Grieße aufgeteilt werden.

When grinding, for example cement, the subject of the application can result in the following advantages:

• the feed material is divided into product sizes and coarse sizes, whereby the coarse sizes can be fed to clinker pre-shredding and the sizes can be fed to a ball mill,
• the feed material can be divided into PZ 45, PZ 35 and Gresse.

• je nach Ausführung des Sichters und Betriebsart hat der Anwender die Wahl zwischen mehreren Sichtspaltdicken und Durchmessern, wobei der Anwender hierbei variabler in der Trennkorngröße ist,
• die Strömungsverhältnisse im Sichtspalt zwischen den beiden Rotorschaufelkränzen sind gleichmäßiger als im radial äußeren Sichtspalt, wodurch der Anwender eine verbesserte Trennwirkung erzielen kann,
• es besteht die Möglichkeit, mindestens drei Festgutströme unterschiedlicher Korngrößenverteilung in einem Arbeitsgang zu erhalten,
• der Spritzkornanteil zwischen dem Grob-Grieße-Austrag und dem zweiten Fertiggut-Austrag kann deutlich herabgesetzt werden.

In addition, the subject of the invention has the following advantages over the St.dT:

• Depending on the design of the classifier and operating mode, the user can choose between several viewing gap thicknesses and diameters, the user being more variable in the size of the separating grain,
• the flow conditions in the viewing gap between the two rotor blade rings are more uniform than in the radially outer viewing gap, as a result of which the user can achieve an improved separation effect,
• it is possible to obtain at least three solid material flows with different grain size distributions in one operation,
• the proportion of spray particles between the coarse-gravel discharge and the second finished product discharge can be significantly reduced.

If the finished goods discharge devices are each operated with an air flow, a so-called "dead flow" will occur in the separation curve in accordance with the ratio of the air throughputs at the second finished goods discharge to that at the first finished goods discharge. The normally disadvantageous "dead river" can be advantageous if e.g. PZ 45 and PZ 35 are to be produced at the same time. The "dead river" causes a high proportion of very fine material to remain in the PZ 35, which can contribute to a tolerable water requirement for the PZ 35.

Figur 1 -

Längsschnitt durch den erfindungsgemäßen Windsichter

Figur 2 -

Draufsicht auf Figur 1 im Querschnitt.

Figur 3 -

Windsichter mit zwei unabhängig voneinander antreibbaren Rotorschaufelkränzen als Prinzipskizze

Figuren 4 und 5 -

Windsichter mit zwei Rotorschaufelkränzen und sich zwischen diesen erstreckenden Leitschaufeln

Figur 6 -

Windsichter mit einer oberen sowie einer unteren Fertiggut-Austragseinrichtung

Figuren 7 und 8 -

Windsichter mit unterschiedlich langen Leitschaufeln

Figuren 9 und 10 -

Windsichter mit als Rundstäbe ausgebildeten zusätzlichen Leitelementen

The invention is illustrated in the drawing using an exemplary embodiment and is described as follows. Show it:

Figure 1 -

Longitudinal section through the air classifier according to the invention

Figure 2 -

Top view of Figure 1 in cross section.

Figure 3 -

Air classifier with two rotor blade rings that can be driven independently of one another as a schematic diagram

Figures 4 and 5 -

Air classifier with two rotor blade rings and guide vanes extending between them

Figure 6 -

Air classifier with an upper and a lower finished product discharge device

Figures 7 and 8 -

Air classifier with guide blades of different lengths

Figures 9 and 10 -

Air classifier with additional guide elements designed as round rods

Figures 1 and 2 show the wind sifter 1 according to the invention on the one hand in longitudinal section and on the other hand in cross section. The following components are shown:
a housing 2, an upper material feed device 3 in the form of a tube, two air inlet ports 4, 5 running tangentially to the housing 2, a first finished product discharge device 6, a second finished product discharge device 7 and a grit discharge device 8. Inside the housing 2 are in this example, two axially superimposed radially outer blade rings 9, 10 are provided. A rotor shaft 11 is arranged concentrically within these blade rings 9, 10 and is guided in bearings 12, 13 in the region of its two ends. The drive for the rotor shaft 11 is only indicated here by the direction of the arrow. Rigidly connected to the rotor shaft 11 are two rotor blade rings 14, 15 and 16, 17 arranged axially one above the other, together with guide blades 14 ', 15' and 16 ', 17', which are provided analogously to the blade rings 9, 10 provided axially one above the other. In this example, the rotor blade rings 14, 15 and 16, 17 are firmly connected to the rotor shaft 11 via radial webs 18, 19, 20. In order to reduce the spray grain area between grit discharge 8 and the finished product discharge devices 6, 7, labyrinths 21, 22 are provided in the lower region of the rotor blade rings 16, 17.

The functioning of the air classifier 1 according to the invention is approximately as follows:
The material to be classified first reaches the cover plate 23 of the rotating rotor blade rings 14, 15 and 16, 17 and is thrown outwards in the radial direction, so that it enters the ring-cylindrical viewing spaces 24, 25 from above, which on the one hand between the rotor blade rings 14, 15 and 16, 17 and on the other hand between the rotor blade ring 15 and 17 and the blade ring 9 and 10 are formed. In these visible spaces 24, 25, the material to be classified is subjected to a suction effect, which results from the difference between the air speed of the blades 9 and 10 fed through the fixed blade rings Visible air and the air conveyed to the outside by the rotor blade rings 14, 15 and 16, 17 due to the rotation. Since the air speed of the visual air supplied to the blade ring 9, 10 via the air inlet ports 4.5 is greater than the speed of the air moved by the rotor rotation of the rotor blade rings 14, 15 and 16, 17, an air flow results overall on the entire circumference of the outer blade rings 9 or 10 transversely to the ring-cylindrical visible spaces 24, 25 and through the rotor blade rings 14, 15 or 16, 17 into the interior 26 of the housing 2.

Depending on its speed, this movement of the visible air takes part of the material falling down in the visible spaces 24, 25 into the visible space 24 on the one hand and into the interior 26 on the other hand. The material taken along thus forms the fine material components, which depend on the air speed and rotor speed set. The material not taken into the area of the viewing gap 24 or the interior 26 falls down as coarse material and arrives in the lower part 27, from which it is discharged through the grit discharge device 8, for example with the aid of an air conveyor not shown. The fine material portion, which is formed in the area of the visible space 24 between the rotor blade rings 14, 15 or 16, 17, reaches the ring-cylindrical upper part 28 of the finished product discharge device 6, while the other fine material portion is collected in the interior 26 of the housing 2 and over a cylinder 29 of the finished product discharge device 6 is supplied. The finished product discharge devices 6, 7 adjoin the cylindrical sections 28, 29 and taper in a funnel shape, being arranged concentrically to one another. The finished goods discharge device 6 runs into the drain pipe 30 and the finished goods discharge device 7 runs into the drain pipe 31, the materials being fed from here to their further determinations.

FIG. 3 shows an alternative wind sifter 32, which likewise contains two rotor blade rings 33, 34, which are arranged concentrically with the radially outer blade rings 9. In contrast to FIGS. 1 and 2, however, the rotor blade rings 33, 34 together with guide blades 33 ', 34' are not connected to one another but can be driven in rotation separately. The rotor blade ring 33 is connected on the one hand to a hollow shaft 35 and in stored its lower region 37. The rotor blade ring 34 is fixedly connected to a drive shaft 36 (not shown) which is guided inside and above the hollow shaft 35 and is mounted at the top and bottom. Both rotor blade rings 33, 34 can thus be driven at different speeds by means of drives (not shown further) in order in this way to achieve an optimal visual effect which is matched to different materials. The finished product discharge devices 6, 7 are designed analogously to FIG. 1 and run out into the drain pipes 30 and 31, respectively.

FIGS. 4 and 5 show a wind sifter 38 which corresponds in its basic structure to the wind sifter shown in FIG. 1. The main differences from the air classifier according to FIG. 1 are due to the fact that the rotor blade rings 39, 40 are designed to be relatively thin radially, the guide blades 41 being designed radially so long that they connect the two rotor blade rings 39, 40 to one another. The finished product discharge devices 6, 7, which open into the drain pipes 30, 31, are provided analogously to those in FIG. 1, so that despite the arrangement of the rotor blade rings 39, 40 there is the possibility, based on the guide blades 41, of two fine fractions to produce different grain sizes.

FIG. 6 shows a further alternative construction of an air classifier 42. The structure of the air classifier 42 corresponds to that shown in FIG. 1. Differences can be seen in the fact that the finished product discharge devices 43, 44 are arranged in such a way that part of the radially inward flowing air-material mixture between the rotor blade rings 45, 46 into the finished product discharge device 43 and thus into the drain pipe arranged below 47 arrives and the further part of the air-material mixture is conveyed upwards into the finished product discharge device 44 due to a negative pressure generated in the inner area 48 of the air classifier 42 and is drawn off there via a pipeline 49. The grains are - as shown in Figure 1 - discharged through a drain pipe 8.

The wind sifter 50 shown in FIGS. 7 and 8 corresponds approximately to the wind sifter described in FIG. Here, too, the rotor blade rings 39, 40 are designed to be relatively narrow radially, with guide vanes, as can be seen in particular in FIG 41 are provided, which connect the two rotor blade rings 39, 40 to one another and, on the other hand, guide vanes 41 'are provided, which are radially shorter and are only connected to the rotor blade ring 40. Alternatively, there is also the possibility of connecting the guide blades 41 ′ to the inner rotor blade ring 39 or of providing an alternating construction.

FIGS. 9 and 10 show a further air classifier 51, which in turn corresponds to the structure of the wind classifier shown in FIG. The differences from FIG. 4 are due to the fact that, in addition to the guide vanes 41 between the rotor blade rings 39, 40, round bars 52 are provided in the area of the rotor blade ring 40 and, on the other hand, round bars 53 in the area of the rotor blade ring 39, the round bars 52, 53 as additional guide devices for serve the material flowing radially from the outside to the inside.

Claims (14)

Air classifier for classifying dusty bulk materials, in particular lime, ground clinker, quartz powder, cement raw material or the like, with a housing, at least one material feed device, at least one finished product discharge device, a fixed blade ring provided inside the housing in its outer area, and a concentric inside of the blade ring, with the rotor and guide vanes arranged so as to be driven in rotation, with an essentially cylindrical cross-section, with visible air being able to be supplied to the blade ring through at least one air inlet nozzle running tangentially to the housing, characterized in that the rotor has at least two rotor blade rings (14, 15 or 16, 17, arranged concentrically to one another) 33, 34, 39, 40, 45, 46) together with guide vanes (14 ', 15' or 16 ', 17', 33 ', 34', 41.41 ', 52.53) includes that below the rotor blade rings ( 14.15 or 16.17.33.34.39.40.45.46) or the guide vanes (14 ', 15' or 16 ', 17', 33 ', 34', 41.4 1 ', 52.53) a plurality of finished goods discharge devices (6, 7, 43, 44) which are independent of one another are provided, and that the slurry is brought together outside the finished goods discharge devices (6, 7, 43, 44) and by a slurry discharge device (8) are removable. Air classifier according to claim 1, characterized in that the rotor blade rings (14, 15 or 16, 17, 39, 40, 45, 46) are rigidly connected to one another. Air classifier according to claim 1, characterized in that the rotor blade rings (33, 34) can be driven independently of one another, in particular at different speeds. Air classifier according to claims 1 and 2, characterized in that the guide blades (41) of the individual rotor blade rings (39, 40) are at least partially radially wide enough that at least two rotor blade rings (39, 40) can be connected to one another, axially below the Guide vanes (41) at least two finished product discharge devices (6, 7) are provided. Air classifier according to claims 1 to 4, characterized in that the guide vanes (41, 41 ') of the rotor blade rings (39, 40) are of radially different widths. Air classifier according to claims 1 to 4, characterized by further guide elements (52, 53) in the area of the rotor blade rings (39, 40) in the form of round bars. Air classifier according to claims 1 to 6, characterized in that the finished product discharge devices (6, 7) are separated from one another by labyrinths (21, 22) and on the other hand from the grit discharge device (8). Air classifier according to claims 1 to 7, characterized in that when using two rotor blade rings (14, 15 or 16, 17, 33, 34, 39, 40, 45, 46) one of the finished product discharge devices (7, 43) is constantly and the other (6.43) can be operated either with or without air flow. Air classifier according to claims 1 to 8, characterized in that at least one finished product discharge device (44) is provided in the upper housing area of the air classifier (42), a part of the finished product and possibly also the fine size being discharged upward in the air stream . Air classifier according to claims 1 to 9, characterized in that the inlet (29) into the first finished product discharge device (6) is cylindrical and is arranged below the rotor blade ring (14 or 16). Air classifier according to claim 10, characterized in that the first finished product discharge device (6) is tapered in a funnel shape and ends in a drain pipe (30). Air classifier according to claims 1 to 11, characterized in that the inlet (28) into the second finished product discharge device (7) is designed as a ring cylinder and is arranged below the rotor blade rings (14, 15 or 16, 17). Air classifier according to claim 12, characterized in that the second finished product discharge device (7), tapering in a funnel shape, surrounds the first finished product discharge device (6) concentrically. Air classifier according to claims 12 and 13, characterized in that the tapering area of the second finished product discharge device (7) ends in a drain pipe (31).

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