DE10040293A1 - Air sifter, to separate a material flow into at least two fractions, has a tangential air entry to give an air flow around the coarse fraction cylinder with an upward movement for an even action on the rotor mantle surface - Google Patents

Abstract

The air sifter, to divide a material flow into at least two fractions, has a vertical rotor (6) rotating in the assembly. The sifting air (2) is divided by a tangential air entry (11) below the sifting zone (17). The air flow rotates around the cylinder (16) for the coarse fraction, with an upward movement to give an even action on the rotor mantle surface. The coarse matter is taken out through a cone.

Description

The invention relates to an air classifier for separating a flow of material into two fractions, with a rotating rotor arranged vertically in the classifier.

Such air classifier for separating a crop flow into two fractions, with one rotating, vertically arranged in the classifier rotor are for example as basket classifiers (Cross-flow classifier) known and in the magazine Zement-Kalk-Gips, issue No. 2/1968, page 69.

The material to be sifted generally passes from above through the cover of the rotor z. B. is designed as a spreading plate, in the annular visual space between the outer Circumference of the rotating rotor and the guide vane ring, the visual air over a spiral inlet channel around the guide vane ring enters over the entire height of the rotor and the material to be sifted is flowed through by the sight air against gravity. The coarse material is thrown outwards by the centrifugal flow field in the rotor and falls along the inner boundary of the vane ring following gravity below in the conically shaped lower part, where it has the classifier through a nozzle Pendulum flap leaves.

Thanks to the rotor, which can be regulated in terms of speed, but also thanks to extensive control the separation air particle size can be in a wide range to be influenced. The fine air stream discharged from the rotor becomes a separator the fines z. B. fed to one or more cyclones; but it can also be used here A fine dust filter can be used to separate the fine material: For a separation sharp sighting, it is especially necessary that the air is evenly distributed on the Visible space is distributed, because for the dwell time of the material to be separated for separation in the air flow only the height of the rotor is available.

A good and even distribution of visible air over the surface of the visible space is the advance Setting for an optimal fines yield with a certain separating grain size.

The object of the invention is to provide a classifier, in which very special Emphasis is placed on optimizing the even distribution of the air flow the lateral surface of the vertically arranged rotor.

This measure will improve the efficiency of the sifting at the same time Energy saving achieved.

The disadvantage of today's rotor sifters is that the sifter air, over one Spiral casing supplied from the outside via a guide vane ring at the same height as the rotor is, with the disadvantage of the uneven loading of the air flow on the Rotor surface at the beginning and end of the volute casing.

According to the invention, the object is achieved in that the classifying air passes through a tangentially arranged air inlet is supplied below the viewing area.

The visual air flow rotates upwards around the coarse material cylinder and leads to it uniform application of the rotor surface.  

Further details, features and advantages of the invention result from the The following explanation is shown schematically in the drawing Embodiment:

It shows:

Fig. 1 shows an axial section through the classifier with the rotor and the air duct.

In FIG. 1, the arrow 1 denotes the object of the is characterized to sifting the material stream in the sifter, whereas the discharge of the coarse material from the conical Sichterunterteil with 1 '.

The arrow 2 indicates the direction of the air flow over the height of the guide vane ring into the rotor, with 1 "denoting the fine fraction of the material flow to be sifted out of the rotor, which as the fine air flow ( 3 ) via the outlet nozzle ( 4 ) the classifier leaves.

The classifying rotor ( 6 ) arranged in the classifier ( 5 ) is driven by the gear ( 8 ) speed-controllable motor via a classifying shaft mounted in the bearing body ( 7 ).

The bearing body is supported by a flange on the classifier cover ( 10 ).

The tangential air flow ( 2 ) flows through the tangentially arranged sight air inlet connection ( 11 ) into the sight air distribution space ( 12 ), which is closed at the bottom by a base plate ( 20 ). The sight air flow moves in a circle around the coarse material cylinder ( 16 ), as a result of which the sight air flow is distributed evenly over the outer surface of the rotor ( 6 ).

The material flow ( 1 ) to be sifted is fed via at least two inlet connections ( 14 ) to the distributor ring ( 15 ) which is connected to the rotor ( 6 ).

Due to the good material scatter, the annular visible space ( 17 ) between the guide vane ring ( 13 ) and the rotor ( 6 ) is fed more evenly over the entire visible surface.

In the annular classifying chamber the material flow (1) through which flows counter to the gravity from the sifting air stream (2). The coarser grain fraction ( 1 ') of the material flow ( 1 ) to be sifted falls down as a result of gravity into the conical sifter lower part ( 19 ) where it leaves the sifter.

The detected from the sifting air stream (2) fine material (1 "), which is in its grain structure depending on the rotor speed and the amount of sifting air stream (2), by the fine material air stream (3) via the outlet pipe (4) one or more cyclone separators ( 22 ) or a filter.

Claims (3)

1. Air classifier for separating a flow of material into two fractions, with a rotating rotor ( 6 ) arranged vertically in the classifier, characterized in that the distribution of the classifying air ( 2 ) is supplied through a tangentially arranged air inlet ( 11 ) below the classifying area ( 17 ) ,
The sight air flow rotates upwards around the coarse material cylinder ( 16 ) and thus drives the rotor jacket surface ( 6 ) evenly. Fig. 1 2. Air classifier according to claim 1, characterized in that the coarse material discharge is carried out via a coarse material cone ( 21 ) in order to avoid material deposits on the base plate ( 20 ) Fig. 1. Fig. 2 3. Air classifier according to claim 1, characterized in that existing cyclone air classifier (patent specification 11 78 284) can be economically converted to the current state of the art using this system. Fig. 3