EP2465617A1 - Method and device for separating fine particles from granulate bulk goods in a pipe - Google Patents

Abstract

The method involves conveying a product stream (3) in input side of a pipe separator (1) provided in pipeline (2). The annular cross-section (6) of pipe separator is greater than that of pipeline. A diameter-enlarged tubular jacket (40) is provided at outside of the annular cross section of pipe separator. The cleaning air (9) is flowed out at preset angle with respect to product stream in the region of a cleaning layer (16) provided in the inner structure (14) of pipe separator so as to separate fine particles from product stream. An independent claim is included for pipe separator.

Description

The invention relates to a method and a device for the separation of fines (particles, threads, nests or dust) from granular bulk materials, which are conveyed in a pipeline.

1. a) während und direkt nach dem Herstellungsprozess (z. B. nach dem Extruder bei Kunststoffgranulat)
2. b) beim pneumatischen oder mechanischen Weitertransport
3. c) beim Mischen und Lagern
4. d) beim Befüllen und Abfüllen

von granulatförmigen Schüttgütern.
Bei diesen Prozessen wird das granulatförmige Schüttgut mechanisch oder thermisch beansprucht. Dabei können sich z. B. kleinere Partikel vom granulatförmigen Schüttgut lösen. Diese feineren Partikel liegen entweder in loser Form zwischen den granulatförmigen Schüttgütern vor oder halten aufgrund von mechanischen Kräften (z. B. verhaken) oder elektrostatischer Kräfte direkt am granulatförmigen Schüttgut. Sehr oft sind diese Gemenge von granulatförmigen Schüttgütern mit Feinanteil nicht gewünscht. Ein hoher Feinanteil erfordert im Prozess einen höheren Abscheideaufwand (Filter) oder verursacht in einem nachfolgenden Prozess (Extrusion von Folien), z. B. Fehlstellen in einer Kunststofffolie. Auch unterliegen Feinanteile oft einem schnelleren Alterungsprozess (z. B. Lebensmittel).In an overall plant for granular bulk materials (plastic granulate, food, etc.) fines can be produced at different points. The origin of fines are, for example:

1. a) during and directly after the production process (eg after the extruder with plastic granules)
2. b) during pneumatic or mechanical onward transport
3. c) during mixing and storage
4. d) during filling and bottling

of granular bulk materials.
In these processes, the granular bulk material is mechanically or thermally stressed. This z. B. solve smaller particles from the granular bulk material. These finer particles are either in loose form between the granular bulk materials or hold due to mechanical forces (eg, hooking) or electrostatic forces directly on the granular bulk material. Very often, these mixtures of granular bulk materials with fines are not desired. A high fines content in the process requires a higher separation effort (filter) or caused in a subsequent process (extrusion of films), eg. B. defects in a plastic film. Also, fines are often subject to a faster aging process (eg food).

For the separation of fines on granular bulk solids, there are different separation principles.

Examples are mechanical, pneumatic, hydraulic, electrostatic, thermal, chemical, biological and optical cleaning processes. In the field of mechanical cleaning processes, sieving represents a simple separation of coarse material and fine material. Pneumatic cleaning processes are, for example, air classification (separation of wheat grain and husk) and countercurrent separation.

For the cleaning of granular bulk materials directly in the pneumatic conveying line, there is still no procedurally implemented solution that has been established in plant construction.

With the subject of DE 10 2008 045 613 A1 Although a promotion of granular bulk materials in a pipeline has become known, in which a separator device is used. Disadvantage of this arrangement, however, is that not the fine fraction is separated from the coarse stream, but that the feed material, which includes both the auszuschcheidenden portion of particles and other substances, as well as the granules is taken as a whole and subjected to a deposition. After the separation, the cleaned material must be returned to the pipeline.
This lacks the feature that such a pipe sifter could be installed directly in the feed line for the feedstock. This is not possible there. Disadvantage of this arrangement is therefore that a relatively large amount of space is required that the plant must be the discharge of the feed material with subsequent separation of particles and threads and that then again the so-cleaned feed stream must be returned.

With the subject of DE 10 2007 047 119 A1 Another compressed air conveyor system for bulk material has become known in which a granulate separator receives the feed material via a suction conveyor. The coarse material is retained on a sieve and sucked the excreted fines. It is therefore basically a vacuum cleaner principle, but this is not suitable for a transport of granular materials in pipelines. Therefore, there is a great procedural effort in the use of such separator.

At the subject of DE 41 13 285 A1 it is a filter, in which it is not possible to integrate the classifier or separator as an integral part in a pipeline, because downstream of the filter separator shown there, a delivery line termination is arranged. The solid is in this case completely separated from the conveying gas, which is done by the aforementioned pipeline termination, and thus it is not possible to integrate such an arrangement in a pipeline for the transportation of feed of feed.

The invention has for its object to form a separator according to the preamble of claim 1 so that it can be integrated directly into a pipeline for the promotion of a feed material, which is conveyed in the form of a pneumatic conveying along the pipeline.

To solve the problem, the method is characterized by the technical teaching of claim 1. A device is characterized by an independent subsidiary claim.

An essential advantage of the technical teaching is that there is now no need for regulated or uncontrolled conveyance of material or conveyed material or pressure maintenance (for example with the aid of a lock) in the vicinity of the separator, as was the case in the prior art. This undesirably affected the pneumatic conveyance of the bulk flow.

In the present invention therefore has the advantage that the pipe sifter according to the invention can now be used as an integral part of the pneumatic conveying suitable bulk flow, which was not previously known.

• ● Er ist strömungsgünstig konstruiert und hat eine sehr geringe Baugröße.
• ● Er beinhaltet keine beweglichen Teile und vermeidet Todzonen.
• ● Schüttgutspezifische Anpassungen können so leicht umgesetzt werden.
• ● Ein Produktwechsel erfordert keinen oder nur einen geringen Reinigungsaufwand.
• ● Er ist eine preisgünstige Variante, da er direkt in die Förderleitung (horizontal und vertikal) eingebaut werden kann.

The invention relates to a pipe sifter, which is installed directly in a pneumatic conveying line (preferably in a flight or Dünenförderung).

• ● It has a streamlined design and is very small in size.
• ● It contains no moving parts and avoids dead zones.
• ● Bulk material adjustments can be easily implemented.
• ● A product change requires little or no cleaning effort.
• ● It is a low-cost version, as it can be installed directly in the delivery line (horizontal and vertical).

From the feed line the granules enter either along the central axis in the pipe sifter or perpendicular to the central axis (shown here with a Disperger). The granules must be distributed well dispersed on a ring cross-section. After cleaning in the ring cross section, the purified product stream is collected in a cone and added back to the delivery line.

The product stream on the input side contains conveying gas, granulate content and fine fraction. The fine fraction contains particles, threads, nests or dust. The fines content of the product stream on the outlet side depends on the separation efficiency of the classifier.

The amount of cleaning air is provided via an air generator. The fines are removed from the recycle gas stream via a separator (eg filter or cyclone). The amount of cleaning air passes into a sealed against the product flow inner body, which is distributed on the circumference, the wall of the inner body passing through, has cleaning openings. Through these openings, the amount of cleaning air enters at a certain angle to the product flow (conveying gas, granulate content & fines) and passes through this product flow. This gives the light product flow components (fines: particles, filaments, nests or dust) a different flight curve than the heavier granules. The change in this curve for the lighter product flow components compared to the flight curve of the heavier granule parts is used for their separation from the conveyed.

The dimensioning of the cleaning openings, as well as their angle to the conveying air flow can be designed individually depending on the product. It can both the direction and the opening cross section are changed. Likewise, nozzle-like inserts can be arranged in the cleaning openings.

The amount of cleaning air flows through the product flow in the ring cross-section and passes through a radially outside of the ring cross-section attached, air-tightly connected to the cleaning air, ring jacket in the exhaust air line. When flowing through the product stream with cleaning air therefore fine particles or filaments or nests of threads are entrained, blown into the radially outer ring jacket, collected there and deposited as laden cleaning air in a separator. The inert granules can not be entrained by the cleaning air blowing obliquely or at right angles into the product stream. They essentially maintain their trajectory.

Since the piping classifier is installed in a pipeline (with pneumatic delivery), there is a higher or lower static pressure at this point than in the environment. As a result, the pipe sifter, the air generator and the separator must be able to operate at a higher or lower pressure level (pressure or suction delivery) than the ambient pressure.

1. a. Er kann an einer beliebigen Stelle direkt in die Förderleitung integriert werden.
2. b. Die Reinigungsöffnungen befinden sich im Innenkörper (ein Gegenstromsichter arbeitet nur mit einer Gegenströmung in einer Reinigungsstrecke)
3. c. Der Gegenstromsichter benötigt ein Ausschleusorgan (z.B. Schleuse) am Grobgutaustritt, um das Grobgut (Granulat) aus dem höheren Druckniveau im Gegenstromsichter auszuschleusen. Ohne ein Ausschleusorgan kann die Reinigungsluft nicht gegen den Produktstrom anströmen (Druck im Grobgutaustritt kann nicht angehalten werden).

The piping classifier differs from the counterflow classifier by the following features:

1. a. It can be integrated at any point directly into the delivery line.
2. b. The cleaning openings are located in the inner body (a countercurrent sifter works only with a countercurrent in a cleaning section)
3. c. The countercurrent sifter requires a discharge element (eg lock) at the coarse material outlet in order to discharge the coarse material (granulate) from the higher pressure level in the countercurrent sifter. Without a discharge element, the cleaning air can not flow against the product flow (pressure in the coarse material outlet can not be stopped).

The subject of the present invention results not only from the subject matter of the individual claims, but also from the combination of the individual claims with each other.

All information and features disclosed in the documents, including the abstract, in particular the spatial design shown in the drawings, are claimed to be essential to the invention insofar as they are novel individually or in combination with respect to the prior art.

In the following the invention will be explained in more detail with reference to drawings showing only one embodiment. Here are from the drawings and their description further features essential to the invention and advantages of the invention.

Figur 1

schematisierte Darstellung eines Rohrleitungssichters nach der Erfindung

Figur 2:

der Gesamtaufbau mit Fliessbild des Rohrleitungssichters nach Figur 1

Figur 3:

eine Variante des Aufbaus gegenüber Figur 2

Figur 4:

eine weitere Variante bezüglich des Aufbaus im Vergleich zu Figur 2

Figur 5:

schematisiert die Darstellung der Abreinigungsstrecke

Figur 6:

ein weiteres Beispiel im Vergleich zu Figur 5 bezüglich der Richtung der geführten Luftströme

Figur 7:

Darstellung verschiedener Möglichkeiten zur Führung der Abreinigungsluftströme

Figur 8:

eine gegenüber Figur 1 abgewandelte Variante, bei der das Aufgabegut in einem Winkel zur Längsachse nach der Abreinigung radial auswärts gerichtet abgelenkt wird.

Figur 9:

eine Darstellung wie Figur 1, bei der die Reinigungsluft von innen nach außen strömt

Figur 10:

eine Variante zur Figur 1 bei der die Reinigungsluft von außen nach innen strömt.

Show it:

FIG. 1

Schematic representation of a pipe sifter according to the invention

FIG. 2:

the overall structure with flow pattern of the pipe sifter to FIG. 1

FIG. 3:

a variant of the construction opposite FIG. 2

FIG. 4:

Another variant in terms of the structure compared to FIG. 2

FIG. 5:

schematizes the representation of the cleaning section

FIG. 6:

another example compared to FIG. 5 concerning the direction of the guided air flows

FIG. 7:

Presentation of various options for managing the Abreinigungsluftströme

FIG. 8:

one opposite FIG. 1 modified variant in which the feed material is deflected directed radially outwardly at an angle to the longitudinal axis after cleaning.

FIG. 9:

a representation like FIG. 1 in which the cleaning air flows from the inside to the outside

FIG. 10:

a variant to FIG. 1 in which the cleaning air flows from outside to inside.

The pipe sifter 1 is used for the deposition of fines (fine particles or monofilaments or nests of threads or dust) of granular bulk materials from a pipeline, preferably within a pneumatic conveying line.

It is installed directly on a pipeline 2, preferably within a pneumatic conveying line (preferably in a flight or dune production).

The pipe sifter 1 can be installed at any point of the delivery line.

The piping classifier 1 does not require pressure limitation or mass flow control (e.g., in the form of a rotary valve) directly on its product stream inlet side 3 or product stream outlet side 4. It may be installed horizontally or vertically.

In the vertical design, it can be filled from below or from above with conveying product. In a delivery line, a pneumatic suction or pressure feed operation is possible. The pipe sifter is designed aerodynamically and has only a small size.

From the pipe 2, the product stream 3 passes either longitudinally, obliquely or perpendicular to the central axis 5 in the pipe sizer 1. The granules must be well dispersed on a ring cross-section 6 distributed. The ring cross-section 6 has a larger diameter than the pipe 2. The increase in diameter of the annular cross-section 6 with respect to the diameter of the pipe 2 is in the range between 10 to 500% of the diameter of the pipeline. On the outside, the annular cross section 6 is formed by the enlarged diameter tubular jacket 40 of the pipe 2, while the inner circumferential surface is formed by the outer periphery of the inner body 14.

After passing through the annular cross-section 6 and the cleaning carried out there, the cleaned product stream 4 is collected in a cone 7 of the pipe sifter 1 located downstream of the cleaning level 16 and re-added to the pipe 2.
The amount of cleaning air 9 is provided via an air generator 10 (eg fan). Dust and granules are removed from the recycle gas stream 12 via a separator 11 (eg filter or cyclone). This cleaning circuit 13 can operate at different pressure levels. The self-adjusting pressure level is dependent on the pressure at the installation of the pipe sifter. 1

A closed and thus gas-tight inner body 14 has at the periphery distributed cleaning openings 15 which break through the jacket of the inner body 14. Through the cleaning openings 15, the introduced into the interior of the inner body 14 cleaning air 9 can enter or exit. Both directions of flow of the cleaning air 9 are possible (see the Figures 9 and 10 ). Preferably, however, the cleaning air 9 will flow out of the inner body 14 through the cleaning openings 15 into the annular cross-section 6 in the region of the cleaning plane 16 (see FIG FIG. 1 and 7 ) and there meet at an angle to the axial product flow 18. For ease of description, this variant will be described in more detail below.

When flowing through the product stream 18 at an angle to this product stream 18 impinging cleaning air 9 fine particles or filaments or nests of threads or dust are entrained radially outward and collected in a radially outwardly surrounding the cleaning holes 15 ring jacket 17 and in an air-tight adjoining separator 11th deposited. The inert granules can by the cleaning air 9 are not entrained and essentially maintain their axial direction of flight (parallel to the longitudinal axis of the inner body 14).

The inner body 14 has one or more feeds in the form of an inlet nozzle through which the cleaning air 9 can be supplied or removed.

The dimensioning of the inner body 14 and the cleaning openings 15 can be designed individually for each product.

The optional operation with an acceleration air amount 20 is possible. In this case, a part of the cleaning air quantity 9 is branched off and the conveying air 21 is supplied close to the product inlet 3. This portion is returned to the cleaning circuit 13. This is in FIG. 3 shown.

The optional operation "partial Förderluftausblasung" with the aid of eg control element 22 via the cleaning air circuit 13 is also possible. As a result, the amount of conveying air is reduced at the product outlet. This is in FIG. 4 shown.

The FIG. 4 shows as a further variant that the control element 22 'can also be arranged on the suction side of the air generator.

According to the FIGS. 2 to 4 the air generator 10 sits in the cleaning circuit 13.

The in the FIGS. 2 to 4 shown separator 11 may be formed as a filter or cyclone.

According to FIG. 1 the active principle of the present invention is that the feed material 33, which is conveyed in flight promotion in a pipeline 2, is radially split in the region of the central longitudinal axis 5 of the pipe classifier 1, thus in a ring cross-section 6 of larger diameter on the outer circumference of an enlarged inner diameter body 14 to be directed.

The radial splitting of the feed material 33 takes place by means of an end-side cone 38, which is arranged on the end face of the approximately cylindrical inner body 14, which serves only the air flow of the feed material 33 and the lateral surface of which forms the radially inner boundary of the annular cross-section 6.

The outer boundary of the annular cross section 6, in which the feed material 33 to be cleaned is conveyed, is formed by an outer casing of the pipe sifter 1, which is designed as an annular ring 17 enlarged in diameter. The feed material 33 flows radially in the annular cross-section 6, which are typical for the flight promotion gas velocities of z. B. in the range 18 to 40 meters per second. This speed is product dependent.

It is important that a splitting or a radial distribution of the feed material 33 takes place in the form of an annular Massengutstromes by circulating the inner body 14, the flow around the lateral surface has a larger diameter than the diameter of the pipe 2, so the feed material 33 uniformly in shape to promote a product curtain along the inner body 14 along.

The invention is not limited to that the pipe 2 coincides in alignment with the central longitudinal axis 5 of the pipe sifter 1.

In another embodiment, it may also be provided that the feed material 33 at an angle of z. B. 90 degrees or at other angles, which are inclined to the center longitudinal axis 5, is entered.

It is now important that a cleaning air flow from cleaning air 9 passes through the so-called annular product curtain bulk flow at least at a certain angle to the flow direction of the bulk flow, so the lighter product flow components (fines: particles, filaments, nests or dust) from the bulk flow out radially outward directed to convey and in the area of an outside of the ring cross-section 6 of the Pipe sifter 1 subsequent annular casing 17 to convey, which is penetrated by the cleaning air 9 approximately perpendicular.

The terms "approximately radial" or "approximately perpendicular" for the angle between the cleaning air 9 and the axial conveying direction of the object to be cleaned 33 are to be understood as exemplary only as a preferred embodiment. However, this angle is variable within wide limits. This will be later based on the FIGS. 5 and 6 explained in more detail.

In addition, the invention is not limited to that the cleaning air flows radially from the inside out into the feedstock to be cleaned, after the FIG. 10 the reverse flow direction shows.

In this embodiment of the invention it can also be provided that the cleaning air flows radially from outside to inside the feed material and thus the cleaning air flow is carried on the inside of the pipe sifter and not on the outside, as shown in the later drawings ( FIG. 10 ) is described in more detail.

In the illustrated embodiment is after FIG. 1 the radial flow through the cleaning air stream from the otherwise air-impermeable inner body 14 by associated cleaning openings 15 in the shell of the inner body 14, wherein the cleaning air 9 in the direction of arrow 24 the feedstock 33 receiving annular cross-section 6 flows through.

The cleaning air 9 is circulated, wherein the cleaning air 9 flows in the direction of arrow 37 in the return gas flow 12 of a cleaning circuit 13 and is introduced in the direction of arrow 23 via an inlet port on one side of the pipe sifter 1.

After the cleaning of the feed material 33 (passing through the cleaning level 16), the thus cleaned feed material flows through the ring cross-section 6 as purified product stream 4 via a conically widening annular nozzle 8 on the outer circumference of the annular cross-section 6 and arrives in the direction of arrow 26 second cone 7, where the thus purified product stream 4 is returned in the form of a flight promotion in the pipeline 2. The conically widening radially outward shaping of the annular nozzle 8 provides an improved "catching power" - less contour - for the effluent through the annular nozzle 8, purified product stream.

With the given description of the method, there is the advantage of the invention, namely that the pipe sifter 1 is integrated directly into the pipe 2 provided for the flight promotion without any pipe connections or discharges of the bulk material stream from the pipe 2 required.

The invention is not limited to the integration of a pipe sifter 1 in a pressurized pipeline 2, but also relates to pipe sifter 1, which work together with a negative pressure in the pipeline 2.

In both cases, a flight promotion or Dünenförderung the abuzinigenden feedstock 33 is provided in the pipeline 2. The operating point for the generation and the guidance of the cleaning air 9 can according to the FIGS. 2, 3 and 4 also be provided differently.

When using a Saugförderung the pressure in the cleaning circuit is also negative to the atmosphere to allow generation of cleaning air 9 in the annular cross section 6 of the pipe sifter 1.

In a development of the present invention, it can also be provided that the cleaning circuit 13 is open, which means that it is not designed as a closed circuit, but that the cleaning air 9 in the in FIG. 1 shown nozzle blown in the direction of arrow 23 and flows freely from the output side arranged nozzle as a return gas stream 12 in the direction of arrow 25 without the return gas stream 12 is collected in any way. So it can take place a free blowing into the atmosphere.

When using such an open system for the cleaning circuit 13 care must be taken that the amount of cleaning air is controlled so that the amount of air blown corresponds approximately to the amount of air entered for the cleaning air flow.

Accordingly, the invention relates to a pipe sifter 1, which can be used both in a negative pressure or pressure relief with respect to the pipe 2.

In FIG. 5 schematically a cleaning in the pipe sifter 1 is shown.

It can be seen that the feedstock 33 is guided as a product curtain in the annular cross section 6 along the outer circumference of the inner body 14 in the direction of arrow 26, wherein the feedstock 33 of granules 28 and thus blended and separated particles 29 and threads 30 consists.

As soon as the feed material 33 conveyed in the direction of arrow 26 in the ring cross-section comes into the region of the cleaning plane 16, the desired separation takes place.

The cleaning air 9 flows in the direction of arrow 19 in the interior of the inner body 14 and flows in the region of the wall of the inner body 14 by breaking cleaning openings 15 in the annular cross-section 6 inside.

The size of the cleaning openings 15 and their dimensions determines the speed of the air flow, which blows in the direction of arrow 19 through these cleaning openings in the annular cross-section 6 of the pipe sifter. The size of these cleaning openings 15 and their dimensions are variable within wide limits.

With the design of the cleaning openings 15 and the speed of the cleaning air flow 9 and its direction can be adjusted in the cleaning level 16, as shown in the FIGS. 6 and 7 will be explained later.

The annular cross-section 6 is interrupted by the cleaning openings 15 extending over the entire outer circumference on the outer circumference of the inner body 14 over an angle of 360 degrees so as to form the cleaning plane 15 arranged therein. The cleaning openings are thus designed as an open ring cross-section. Of course, struts and other bridging means for axially bridging the open ring cross-section are present in order to avoid complete separation of the lateral surface of the inner body 14.

In a further embodiment of the present invention, it can also be provided that cleaning openings 15, for example, are distributed uniformly at a distance on the outer circumference of the inner body 14. are arranged as perforations or slot openings in the lateral surface of the inner body 14.

Therefore, they do not necessarily form a continuous, interrupted only by struts ring opening, but it can also be distributed evenly spaced around the circumference arranged cleaning openings 15 may be provided.

The shaping of the cleaning openings can be slit-shaped, cylindrical and in any other contour.

Likewise, outflow apertures can be used which ensure a certain orientation of the cleaning air 9 in the annular cross-section 6.

Likewise, these outflow openings can be formed as nozzle openings to allow an increase in the flow velocity of the outflowing from these nozzle openings cleaning air 9.

In the embodiment according to FIG. 5 passes through the cleaning air 9 approximately obliquely in the direction of arrow 24 to be cleaned Massengutstrom (feed material 33) and thus ruptures the separated particles 29 and the threads 30 in the direction of arrow 24 by an associated Abscheideöffnung 31 in the outer circumference of the Rohrsichtungssichters 1. The cleaning air 9 flows over the Separation opening 31 in a ring cross-section 17 a, which is arranged on the outer circumference of the pipe sifter 1 approximately in juxtaposition to the separation opening 31 and the air-tight is integrated into the cleaning circuit 13.

The thus purified bulk material flow continues in the direction of arrow 26 in the annular cross section 6, is captured in the mouth of a conically widening outwardly annular nozzle 8 and continues to flow in the annular cross section 6 on the outer circumference of the inner body 14 along. Beyond the cone 38 ', the ring cross-section 6 unites again centrally with the pipe 2, so that the cleaned product stream 4 flows there into the pipe 2.

In FIG. 6 various possibilities of air guidance of the cleaning air flow from the inside of the inner body 14 through the cleaning openings 15 are shown.

The cleaning air flow flows in the direction of arrows 19 coming from the inside of the inner body 14 coming through the cleaning openings 15, and depending on the steering of the cleaning air flow, he is either z. B. directed in the direction of arrow 24 obliquely against the inflowing in the direction of arrow 26 product stream 8, or it can also be directed in other angular directions, as shown by the direction of the arrow 24 '.

Also plays for the direction of the cleaning air flow in the annular cross-section 6 for forming the cleaning level 15 the - aligned or non-aligned - position of the separation opening 31 to the position of the plane of the cleaning openings 15 a role.

In FIG. 6 It is shown that it is not necessary for the solution that the center axis 34 of the separation opening 31 coincides in alignment with the central axis 35 of the cleaning openings 15. Here, an offset 36 may be provided. The offset can be offset to the left or to the right.

The FIG. 6 shows a left offset 36. The left side offset means that the offset is located upstream of the bulk flow. However, it can also be downstream.

These directions also determine the direction of the outflow cleaning air flow, in the example after FIG. 6 flows out of the outlet port 39 in the arrow directions 37.

The FIG. 7 shows various ways of guiding the cleaning air flow, where various possible angular positions are shown.

In a preferred embodiment, the cleaning air flow will flow in the radial direction (90 degrees) in the direction of arrow 24 through the cleaning openings into the annular cross-section 6 and there approximately meet in the vertical direction to be cleaned mass flow (feed material 33).

The invention is not limited thereto. The invention shows that the cleaning air 9 can also be directed in the directions of the arrows 24 ', 24 ", 24''' and 24 '''', resulting in angular positions in the range between 0 degrees and 180 degrees as shown in FIGS FIG. 7 is shown schematically.

This inflow into the feedstock 33, which is conveyed with an assumed angular position of 0 degrees along the annular cross-section 6, also influences the outflow of the cleaning air stream, which contains the particles 29 and threads 30 to be cleaned off. Here, different arrow directions 37 ', 37 "and 37' '' are shown, in which the cleaning air flow, which now carries the fines, flows out as a return gas flow 12.

The FIG. 8 shows as a further embodiment, conically widening to the flow direction of the product stream 3 widening cleaning openings 15. The inner body 14 is divided into two with respect to the inner body 14 extending over the circumference cleaning openings. It forms a first cylindrical hollow body upstream of the cleaning openings 15 with a smaller diameter than comparatively the second part of the inner body, which merges downstream of the cleaning openings 15 in a larger diameter. Thus, the cleaned product stream 4 receiving annular nozzle 8 is enlarged in diameter relative to a ring nozzle 8 after FIG. 1 , It is thus achieved a lesser outline in abzureinigenden product stream 3, because a flow of the product stream 18 is oblique to the longitudinal axis of the annular cross-section 6. It is therefore a radially outwardly offset collection path for the cleaned product stream 18th
However, it should be ensured that the flow velocity in the annular cross-section 6 upstream of the cleaning openings 15 corresponds approximately to the flow velocity in the annular cross-section 6 downstream of the conically widening cleaning openings.

The FIG. 9 shows the structure of the pipe sifter 1 according to the FIG. 1 , wherein the different flow directions are shown to clarify the function.

The FIG. 10 shows the kinematic reversal of the leadership of the cleaning air flow of the cleaning air 9 compared to FIG. 1 and 9 , In FIG. 10 the leadership of the cleaning air flow from radially outside to radially inside. The cleaning level 16 is thus laid in the interior of the inner body 14.

The method according to the invention is thus distinguished by the fact that the product stream 3 is radially spread on a ring cross-section 6 on the input side of a pipe sifter integrated in the pipeline and there in the region of a cleaning plane 16 from an angle to the direction of the spread product stream. 3 flowing cleaning air stream 9 is interspersed, which deflects the entrained in the product stream 3, lighter particles, threads, nests, dust or the like. From the trajectory of the heavier granules and promotes in a flowed through by the cleaning air 9 ring jacket 17, from which they by means of a separator 11th or cyclones are removed. A first embodiment provides that the cleaning air stream 9 passes through the product stream 3 at an angle from radially inward in the direction radially outward and thus deflects the lighter particles from their trajectory into a radially outer annular jacket 17, through which the cleaning air flows.

In the second embodiment it is provided that the cleaning air stream 9, the product stream 3 at an angle from radially outward direction radially inward passes through and thus deflects the lighter particles from their trajectory in a radially inner annular jacket 17, which is traversed by the cleaning air.

drawing Legend

1

Pipe sifter

2

pipeline

3

Product flow - input side

4

Product flow - outlet side

5

central longitudinal axis

6

Ring cross section

7

cone

8th

banjo union

9

cleaning air

10

air heaters

11

separators

12

Rear gas flow

13

Cleaning circuit

14

inner body

15

cleaning openings

16

cleaning level

17

ring jacket

18

product flow

19

arrow

20

Accelerating airflow

21

conveying air

22

regulating element

23

arrow

24

Arrow direction 24 '

25

arrow

26

arrow

27

arrow

28

granulate

29

particle

30

thread

31

separation opening

32

-

33

feed

34

Central axis (from 31)

35

Central axis (from 15)

36

offset

37

arrow

38

Cone 38 '

39

outlet

40

pipe casing

Claims (12)

Method for separating fine particles (29, 30) from granular bulk materials (3, 18, 33) which are conveyed as product stream (3) by means of flight or dune conveyance in a pipeline (2), characterized in that the product stream (3 ) is radially spread on a ring cross-section (6) on the inlet side of a tube sifter (1) integrated into the pipeline and penetrated in the region of a cleaning plane (16) by a cleaning air stream (9) flowing at an angle to the direction of the spread product stream (3) Is, which in the product stream (3) entrained, lighter particles, threads, nests, dust or the like. From the trajectory of the heavier granules deflects and promotes in one of the cleaning air (9) through which flows annular sheath (17) from which they by means of a Separator (11) (eg cyclones) are removed. A method according to claim 1, characterized in that the cleaning air (9) is guided in a closed circuit through the pipe classifier (1). A method according to claim 1, characterized in that the cleaning air (9) is guided in an open flow path through the pipe sifter (1). Method according to one of claims 1 to 3, characterized in that for forming an acceleration air quantity (2) in the cleaning zone (16) a part of the cleaning air quantity (9) is branched off and the conveying air 21 is supplied close to the product inlet (3), (Fig. 3). Method according to one of claims 1 to 3, characterized in that a partial Förderluftausblasung with the aid of a control element (22) via the cleaning air circuit (13), wherein the conveying air quantity is reduced at the product outlet, (Figure 4). Pipe sifter (1) for the separation of fine particles (29, 30) of granular bulk materials (3, 18, 33), which are conveyed in a product stream (3) by means of flight or Dünenförderung in a pipeline (2), characterized in that it is arranged in an air-tight manner in the pipeline (2) and consists of a double jacket (14, 40) which is widened in relation to the diameter of the pipeline (2) and forms an annular gap (6) extending in the axial direction, through which the product stream to be purged (3 ) is conveyed through, that the annular gap (6) by a radial, over the circumference of the annular gap extending cleaning plane (16) is interrupted, injected by the cleaning air (9) at an angle to the conveying direction of the product stream (3) in the product stream (3) is, and that radially outwardly of the cleaning plane (16) an annular gap (6) encompassing ring jacket (17) is arranged, which receives the cleaning air (9) and od a separator (11) od he supplies cyclone. Pipe sizer (1) according to claim 6, characterized in that the annular gap (6) is formed radially inwardly by the lateral surface of an inner body (14) having distributed on the periphery cleaning openings (15) which break through the jacket of the inner body (14) and by which the cleaning air (9) at an angle to the product stream (feed material 33) can be introduced into the product stream. Pipe sifter (1) according to one of claims 6 or 7, characterized in that the radial spreading of the product stream (3) by a frontally on the inner body (14) arranged cone (38), which with a parallel cone of the pipe (2) the Ring cross section (6) forms. Pipe classifier (1) according to any one of claims 6 to 8, characterized in that after the cleaning of the feed material (33) (passing the cleaning level 16), the purified feed as a purified product stream (4) via a second cone (7) in the pipeline. 2 is traceable. Pipe sifter (1) according to any one of claims 6 to 9, characterized in that the cleaning air (9) coming from radially inwardly in the direction radially outward in the product stream to be cleaned (3, 33) is steerable. Pipe sifter (1) according to one of claims 6 to 9, characterized in that the cleaning air (9) coming from radially outward in the direction radially inwardly in the product stream to be cleaned (3, 33) is steerable, (Fig. 9). Pipe classifier (1) according to any one of claims 6 to 11, characterized in that the feed material (3, 33) promoting annular gap (6) downstream of the cleaning openings (15) at approximately constant conveyor cross section is offset radially outward, (Fig. 8).

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