DE2551457A1 - DEVICE FOR SEPARATING LARGE MATERIAL AND FINE MATERIAL IN THE CENTRIFUGAL FIELD - Google Patents

Description

Device for separating coarse material and peing material in a centrifugal field

The invention relates to a device for separating coarse material and fine material in a centrifugal field consisting of a cylindrical one Hollow body with one end of the jacket tangentially opening into a helical line of sight material fluid supply pipe, at least an axially arranged fine material outlet pipe and a tangentially exiting one attached to the other end of the jacket Coarse material outlet pipe.

The separation of powdery, granular or fibrous goods according to certain grain sizes, densities or shapes is necessary for the Separation of unwanted components or for fractionation of mixtures.

Various devices are known for this.

In the countercurrent sifter it flows under gravity or centrifugal force A gas flow counteracts the falling mixture, which separates the light particles and transports them away. The flow is not uniform and causes an unclean separation. In addition, an economic separation can only be made in the rough range (d> 100yum), because the smaller the particles

Le A16819

709820/0586

₃ 255U57

are, the lower the limit load, which is well known indicates the condition in which all particles of a given size are just being transported away. Hence there is only one low gas velocity possible, which in turn results in a low throughput.

With the cross-flow separator, this is turned into an air stream from the side Mixture introduced under the influence of air and mass forces fanned out. The air flow then transports the fine material away, while the coarse material falls down by gravity. The residence time of the goods in the viewing zone is only short, so that the performance is low. With a high load (product flow to gas flow), the selectivity decreases, especially since an unfavorable accumulation of material on the opposite wall of the feed point can occur.

In a spiral sifter one is introduced into a round body Mixture air flow into the coarse material thrown outwards by centrifugal force and into the coarse material with it the. Fine material flowing out of the air stream is broken down. The disadvantage is the high air throughput and the low overload capacity due to overload. This is due to friction on the wall Mixture braked, this changes the centrifugal force and thus the size of the separating particles. The separation time is great because that Product transported as a strand along the wall and thereby the fine material is hindered from the drain. With abrasive A high level of wear and tear is to be expected on the product.

Furthermore, there are separators in which the separation of fine particles from a mixture kept in a fluidized state in one Container with lower perforated plate takes place. Batch operation limits the performance. Because of the long lines of sight In a mixture, this process is energy-intensive, because there must be a sufficient amount of air at the appropriate pressure Flow through the mix. The size is many times larger than other classifiers with the same throughputs.

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The invention is based on the object of finding a device that has a within a large grain size range Mixture flow from dust quickly without significant overlap of the two grain size ranges by sifting into coarse and fine material separates, the wear and the added amount of pluid should be as low as possible.

This object is achieved in that in the jacket of the elongated, cylindrical hollow body on the Area distributed outlet openings for the sighting fluid from the surrounding distribution chamber, into which in turn sighting fluid inflow pipes open out, are located.

The advantages achieved by the invention are in particular that the continuously advancing flat mixture of material at each point of the cylindrical circumference the amount of fluid required for the sifting process is supplied in a targeted manner can be. This makes it possible to run the device in strand or fluidized bed operation, the latter being the case leads to shorter viewing times due to the moving, loose packing structure. At the same time, the adjustable fluid metering allows Adaptation of the device to different grain sizes or densities without loss of selectivity. The material to be viewed is when sifted Treated gently so that the device can also be used for sensitive substances.

The energy requirement is low, as only a small amount of fluid is consumed, which is particularly advantageous in the case of fluids to be cleaned, cooled or heated to be recovered 1st.

The construction is simple and can easily be adapted to the operating requirements by means of axial expansion. In addition, the Device can be installed in any position. The wear that would otherwise be destroyed in a very short time with abrasive mixes the sifter wall is through the air cushion in between small amount.

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According to a special embodiment of the invention Device, the outlet openings in the jacket of the cylindrical hollow body 1 'for the sighting fluid at an angle of 2 to ^ 0 °, preferably 5 to 15 °, to the perpendicular of the radius and / or at an angle of 2 to 20 °, preferably 4 to 12 °, arranged inclined to the axis in the conveying direction.

With the aid of the outlet openings in the same direction, the ratio of the drag force can be determined with an appropriate supply of visual fluid be kept equal to the centrifugal force to the outside, so that the cut size does not change over the entire working area. This advantage is especially true for small ones Particles <c 10 / µm efficient.

According to a further embodiment, a helical rising guide helix is used for the mixture in the cylindrical hollow body arranged.

The advantage of this construction is based on the fact that the separation conditions are met by the more precise guidance of the mixture to be classified become more even in the sifter. A backflow of the mixture or an accumulation is avoided. The dwell time each individual particle in the classifier is the same. It is easier to adhere to a given cut size.

In a further embodiment of the invention, several separators of different separating grain sizes are connected one behind the other in this way / that the coarse material outlet pipe of the preceding sifter is the same as the sifted material fluid supply pipe of the following sifter.

Particular advantages are that when a mixture flow is divided the mixture is metered into several fractions only once, namely at the first sifter Has. In this way, preparative separation and grain size analysis can also be carried out quickly and reliably.

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In the drawing, the device according to the invention is shown purely schematically and its mode of operation on two Examples explained below.

example 1

Via a material to be fluid supply pipe 1 (diameter 25 ″ mm), ^{around sifting} air with a volume flow of 90 nr / h is passed between the distribution space 2 made up of two nested pipes and passes through the outlet openings 3 below an angle of 11 ° to the vertical of the radius and 9 ° to the axis with a diameter of 1 mm and an occupancy density of 10 exit

openings / 4 cm (Conidur plate No. 70) in a cylindrical Hollow body 5 are arranged, which has a length of l4o mm and a Has a diameter of 100 mm. A silicon dust of approx. 6θ kg / h is introduced with air via the material-fluid-feed pipe 6 tangentially to the helical spiral 7 and pneumatically conveyed as a fluidized bed spirally along the wall of the shell 4 on a visual air cushion. The fine goods (about 25 #) leaves the cylindrical hollow body 5 axially Fluid material outlet pipes 8, while the coarse material (about 75 #) in Coarse material outlet pipe 9 arises. The cut size is 22 µm.

example 2

When using an air volume of IbO nr / h the then falls adjusting streak of mixed material 20 $ fine material and 8o # coarse material to the designated places. The separation size is 16 µm.

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Claims (4)

Claims; Device for separating dust into coarse and fine material in a centrifugal field consisting of a cylindrical hollow body with one end of the jacket tangentially opening into a helical line of sight material fluid supply pipe, at least an axially arranged fine material outlet pipe and a tangentially exiting one attached to the other end of the jacket Coarse material outlet pipe, characterized in that in the jacket (4) of the elongated cylindrical hollow body (5) over the surface distributed outlet openings (3) for the sighting fluid from the surrounding distribution chamber (2), into which sighting fluid inflow pipes (1) open, are located. 2.) Device according to claim 1, characterized in that the outlet openings (3) in the jacket of the cylindrical hollow body (5) for the sealing fluid at an angle of 2 to 30 °, preferably 5 to 15 ° to the perpendicular of the radius and / or at an angle of 2 to 20 °, preferably 4 to 12 °, to the axis in the conveying direction are arranged inclined. J.) Device according to claim 1,2, characterized in that a helical rising guide helix (7) for the mixture is arranged in the cylindrical hollow body (5). 4.) Device according to claim 1, 2 and 3, characterized in that that several separators of different separating grain size are connected in series so that the coarse material outlet pipe (9) of the preceding The classifier is the same as the classifying material fluid supply pipe (6) of the following classifier. Le A 16 819 - 6 709820/0586