EP1807223B1 - Separator comprising a separating rotor for the separation of dust fibrous or particulate material - Google Patents

Description

The invention relates to a separator according to claim 1.

Air classification presents itself as a process for separating dusty, granular or fibrous goods, the separation according to the rate of descent being effected under the influence of grain shape, grain size and density.

A quality criterion of an air classifier is the separation effect, whereby, if possible, all particles which are larger than the separation limit are conveyed into the coarse material and smaller particles into the fine material.

For air classifiers so-called classifier wheels come from e.g. Steel or ceramic is used, with the possibility also exists to arrange several classifying wheels in a device to achieve an increase in performance.

The use of separator wheels of Al ₂ O ₃ or SiC in conjunction with a corresponding lining of a classifier can be achieved that iron-free powder available. Conventionally used Sichterräder have a substantially cylindrical shape with a bottom and a cover plate, which is usually provided in or on the bottom plate a receptacle for a motor drive, in particular for a drive shaft, such as from the document US-A-5,377,843 ,

Between the spacers spaced apart plates is a plurality of conveying blades, which provide the necessary flow of good in conjunction with the aforementioned drive. The blades coming into contact with the discontinued material must be extremely resistant and resistant to abrasion, especially at high speeds, in order to achieve a technologically meaningful service life of the respective classifier wheel.

With respect to the use of a classifier wheel within a flow chamber classifier head, refer to the multifunctional apparatus for grinding, sifting, mixing and / or deagglomeration according to DE 100 45 160 A1 made aware. Also in the local device is a Sichterrad application, which has a plurality of radially oriented blades between two opposite circular surfaces. The known classifier consists of a classifier housing with a spiral outlet for fines and has a closable by a door opening, wherein the classifier wheel is rotatably adjustable mounted on the door and the door is externally connected to an electric motor drive. In this way, it is ensured that only the classifier wheel itself comes into contact with the material to be inspected and damage to the axis or the receptacle for the classifier wheel can be largely excluded.

However, it has been shown that known sizing wheels do not meet all the requirements for different applications in terms of selectivity, the yield of fines and the service life. In particular occurs in conventional classifier wheels, in particular at the fine material outlet on a very high, hardly avoidable wear, with the result that a more or less frequent change of classifier wheel and thus a production interruption is necessary.

From the foregoing, it is therefore an object of the invention to provide a separator, which has a higher efficiency and allows trouble-free operation.

The object of the invention is achieved with a separator according to claim 1, wherein the dependent claims comprise at least expedient refinements and developments.

In a proposed Sichterrad is based on a known, substantially cylindrical body, wherein the cylindrical body has a concentric core or pin for receiving a drive shaft, preferably for a motor drive and a Variety over the cylinder circumference distributed flow openings and a fine material outlet has.

The cylindrical body consists of a monolithic block, wherein the cylinder jacket thickness is chosen to be much larger compared to the prior art. The cylinder jacket thickness is in the range of 0.1 to 0.4, preferably 0.125 to 0.3 times the cylinder outer diameter.

Between the, e.g. By milling introduced flow openings remain significant webs in the cylinder jacket, so that care is taken to ensure sufficient resistance to wear. The flow openings are designed as slots running in the cylinder longitudinal axis direction and / or a multiplicity of radially oriented bores.

In a preferred embodiment of the classifier wheel, the width of the slots is set smaller than the width of the remaining webs.

The slots extend, optionally interrupted by a support ring, over the length of almost the entire cylinder.

In the case of the formation of the flow openings as holes, the bore longitudinal axes are each directed to the longitudinal axis of the cylinder in an embodiment variant.

Alternatively, it is possible to arrange the bore longitudinal axes obliquely at an angle, wherein the imaginary extended bore longitudinal axes intersect outside the cylinder longitudinal axis.

The oblique arrangement or oblique orientation of the bores preferably runs in the direction of rotation of the classifier wheel.

Based on a Cartesian coordinate system originating on the cylinder longitudinal axis of the inclination angle of the holes is in the range between 30 ° and 60 °, preferably between 40 ° and 50 °.

The respective holes in the circumferential direction of adjacent rows of holes are arranged staggering staggered.

At the drive end, the cylindrical body has a chamfer, which can usually be designed obliquely or as a circular arc section.

The cylindrical body consists in a preferred embodiment of plastic, in particular a hard polymer.

Furthermore, the cylindrical body comprises a metal core insert, which in turn serves to receive a drive shaft.

Of course, the Sichterrad can be made of a metallic or ceramic material, without departing from the spirit of the invention.

With the use of the separator wheel described, it has been shown that, due to the large number of flow openings, in particular bores, the flowing air or the product / air mixture is distributed very uniformly over the entire surface circumference of the wheel. This results in a very uniform and low overall load of the wheel, i. the wheel surface, resulting in the Quintessenz longer life.

By locating holes in the monolithic body in an area ratio of bore to remaining lands of substantially about 1: 1, higher impeller strengths result allowing higher circumferential speeds of ≥ 60 m / sec, i. Even finer finished goods can be achieved by using the classifier wheel in an air classifier.

Overall, the use of the presented Sichterrads leads to a better selectivity, a higher yield of fines, which in turn is available low-fines coarse material.

The invention generally relates to a classifier with a classifying wheel for separating powdered or granular goods according to the rate of descent under the influence of grain shape, grain size and density, wherein the classifier wheel consists of a substantially cylindrical body with a concentric core or pin for receiving a drive shaft and has a plurality of distributed over the cylinder circumference flow openings and a fine material outlet.

According to the invention, the classifier wheel is non-centrically arranged in the viewing space in such a way that the flow cross section from the material feed side in the direction of the fine material outlet is reduced.

Returning to a finding of the Applicant has been found that in a centric arrangement, the distribution of the air flow in the vicinity of the Sichterrads is very inhomogeneous. This is due to the fact that gas or air is continuously removed from the circulating flow during the flow around the separator wheel. Since the flow cross section around the wheel is constant in known classifiers, the flow rate changes due to the reduced flow rate.
If the flow cross section from the material feed side in the direction of the fine material outlet is reduced, a constant flow velocity is achieved. As a result, constant conditions and thus uniform spreading of the fines are achieved by almost the entire wheel circumference. From the constant flow velocity results in a constant centrifugal force of the particles, which has the consequence that the coarse fractions occupy a constant distance to the Sichterrad. As a result, these coarse fractions no longer come into contact with the classifier wheel and can cause no wear there.

Furthermore, according to the invention, the arrangement of the suction point is tangential to the viewing space, in particular with the above-described non-centric arrangement of the classifier wheel. This technical solution ensures that increased wear or destruction of the wheel is excluded by direct bombardment of Sichtgut, Mahlkugeln or foreign parts. The incoming coarser particles or foreign parts are decelerated on the inside of the classifier. Such in speed slowed particles cause only a slight wear in the coarse grained area due to their lower kinetic energy.

The further development of the classifier according to the invention accordingly creates a homogeneous flow distribution around the classifier wheel, ensures a higher degree of efficiency, leads to a lower level of wear and tear, in particular grinding balls or very coarse material in the classifier not leading to disturbances.

The invention will be explained below with reference to an embodiment and with the aid of figures.

Fig. 1

eine Darstellung eines Sichterrads mit Längsschlitzen im Teilquerschnitt sowie Teillängsschnitt;

Fig. 2

eine Darstellung ähnlich der Fig. 1, jedoch mit einem Sichterrad mit innerem Verstärkungsring;

Fig. 3

eine Darstellung eines Loch-Sichterrads im Teilquerschnitt sowie Teillängsschnitt und

Fig. 4

eine Darstellung eines Sichters mit exzentrisch angeordnetem Sichterrad im Sichtraum.

Hereby show:

Fig. 1

an illustration of a Sichterrads with longitudinal slots in the partial cross-section and partial longitudinal section;

Fig. 2

a representation similar to the Fig. 1 but with a classifier wheel with inner reinforcing ring;

Fig. 3

a representation of a hole Sichterrads in partial cross-section and partial longitudinal section and

Fig. 4

a representation of a classifier with eccentrically arranged Sichterrad in the viewing area.

The classifier wheels shown in the embodiments have a substantially cylindrical shape with a bottom portion which is designed flange-like and with respect to the cylinder axis 2 has a steel core insert 3 for receiving a drive shaft, not shown.

At the opposite end of the bottom of the cylindrical Sichterrads this has an opening portion 4, which serves the fine material outlet.

From the representations especially after the Fig. 1 to 4 It is clear that, in contrast to other known prior art, the thickness or thickness of the cylinder jacket is very large and, for example, in the range to 0.1 to 0.4, preferably 0.125 to 0.3 times the cylinder outer diameter.

In the cylinder jacket 5, as shown in the figures, flow openings are introduced.

According to the Fig. 1 and 2 the flow openings are realized in the form of slots 6. Between the respective adjacent slots remain webs 7, the web width is greater than the slot width in the embodiment shown.

The slots are in the embodiment according to Fig. 2 interrupted by a support ring 8, so that the necessary overall stability of the classifier wheel results even with larger longitudinal dimensions.

The slits 6 preferably extend over the entire length of the cylindrical body, with the exception of the bottom region 1.

The preferred direction of rotation of the classifier wheel is in the respective left part of Fig. 1 to 3 symbolized by an arrow.

Like in the Fig. 1 recognizable, it is possible to make the slots 6 also obliquely. This means that in contrast to the embodiment of Fig. 1 the imaginary longitudinal axes of the slots 6 do not meet on the cylinder axis 2 or cut there.
With respect to an imaginary coordinate system, which has its origin on the cylinder longitudinal axis 2, the slots 6 are as shown Fig. 1 oriented at an angle of, for example, 45 °.

In the embodiment according to the drawing according to Fig. 3 is assumed by a hole-Sichterrad, which also has a bottom portion 1, a cylinder longitudinal axis 2, a steel core insert 3 and an opening portion 4.

Also in this embodiment, the cylinder jacket 5 has a relatively large thickness or wall thickness.

In the cylinder jacket 5 hole-like holes 9 are introduced in a modification of the first embodiment.

The longitudinal axes of the holes 9 may each be directed towards the longitudinal axis of the cylinder (not shown) or at a predetermined angle (see Fig. 3 , left part of the picture).

Accordingly, the bore longitudinal axes of the holes 9 are arranged obliquely at an angle, wherein the imaginary elongated bore longitudinal axes intersect outside the cylinder longitudinal axis 2.

The oblique orientation of the bores 9 preferably runs in the direction of rotation of the classifier wheel (see arrow illustration).

Based on a Cartesian coordinate system originating on the cylinder longitudinal axis 2, the skew angle of the holes 9 is in the range between 30 ° and 60 °, preferably between 40 ° and 50 °.

The respective holes 9 in the circumferential direction of adjacent rows of holes have a staggered arrangement, as shown in Fig. 3 , right part of picture becomes clear.

At the drive end, the cylindrical body according to the embodiments on a chamfer 10.

Compared to standard Sichterrädern occurs in the embodiments of the invention, especially those with a plurality of holes or holes on a lesser and circumferentially uniform wear, so that there are longer service life.

The classifying wheels can be made of machinable steels as well as ceramics such as Al ₂ O ₃ , zirconium oxides, SiC or the like, but also of polyurethanes or plastics.

The geometries of the holes or the slots in the wheel are freely selectable in the field of theory of invention and can be realized according to the selected material types of the wheel by machining processes.

Experiments with kaolin using the air classifier with inventive Sichterrad at the same Sichterrad speed have shown that the maximum fine fineness is 95%, 5.7 microns in a pinwheel according to the invention D. On the other hand, the fineness of a standard wheel is 8.0 μm.

The percentage of defective grain in a standard wheel is between 33% and 34%; in contrast, in the case of a pinwheel according to the invention, only in the range between 30% and 32%. Despite much finer separation results in the use of the doctrine of invention, a better proportion of defective grain.

In further experiments with sand a significantly better selectivity and thus fines yield was detected. The proportion of defective grain was in this case with a standard wheel in the range between 15% and 16%, with the pinwheel according to the invention at approximately 5%.

The separator according to the invention according to the illustration Fig. 4 is formed so that the Sichterrad 80 is not arranged centrally in the viewing space 90.

This arrangement is such that the flow cross-section from the side 100, that is, the material feed side, to the side 110, that is reduced in the direction of fine material outlet. By this reduction of the flow cross-section from 100 in direction 110, a constant flow velocity is achieved. As a result, constant conditions and a uniform application of the fines content are established around the entire circumference of the separator wheel 80. From the consistent Flow velocity results in a constant centrifugal force of the particles (point representations in the Fig. 4 ), with the result that the coarse fractions occupy a constant distance to Sichterrad 80. These coarse fractions then no longer get in contact with the Sichterrad 80 and can not cause wear.

The suction point 120 is oriented tangentially with respect to the viewing space 90. This measure ensures that increased wear or destruction of Sichterrads 80 is excluded by direct bombardment of Sichtgut, Mahlkugeln or foreign parts. The incoming coarser particles 130 are decelerated on the inside of the viewing space 90, so that their kinetic energy is reduced in a meaningful way. In the Fig. 4 the fines outlet is provided with the reference numeral 140 and the coarse material outlet with the reference numeral 150.

REFERENCE NUMBERS

1

floor area

2

cylinder longitudinal axis

3

Steel core insert

4

opening section

5

cylinder surface

6

slot

7

web

8th

support ring

9

drilling

10

chamfer

80

classifier

90

view room

100

Material supply side

110

Direction of fines exit

120

suction

130

particle

140

fines outlet

150

Grobgutaustritt

Claims (13)

1. Separator having a separator wheel for separating dust-like, fibrous or granular materials according to sinking speed under the influence of grain shape, grain size and density, the separator wheel being comprised of an essentially cylindrical body (5) having a concentric core or pin for receiving a drive shaft, a plurality of flow openings distributed across the cylinder's circumference, as well as a fine material outlet (140),
   characterized in that
   the separator wheel is disposed within the separating chamber (90) to be non-centric such that the flow cross-section reduces from the material feeding side toward the fine material outlet (110).
2. Separator according to claim 1,
   characterized in that
   the cylindrical body of the separator wheel is comprised of a monolithic block, wherein the cylinder wall thickness is in the range of 0.1 to 0.4, preferably 0.125 to 0.3 times the cylinder's outer diameter, webs (7) remain between the flow openings in the cylinder envelope, and the flow openings are formed as slots (6) running in the cylinder's longitudinal direction and/or as a plurality of radially oriented bores.
3. Separator according to claim 2,
   characterized in that
   the width of the slots is less than the width of the remaining webs.
4. Separator according to claim 2 or 3,
   characterized in that
   the slots are arranged, where appropriate, interrupted by a support ring (8), to extend over the length of the cylinder.
5. Separator according to claim 2,
   characterized in that
   the longitudinal axes of the bores (9) are each directed toward the longitudinal axis of the cylinder.
6. Separator according to claim 5,
   characterized in that
   the bores' longitudinal axes are arranged to be obliquely extending by an angle, wherein the imaginary prolonged bores' longitudinal axes intersect outside the cylinder's longitudinal axis.
7. Separator according to claim 6,
   characterized in that
   the oblique orientation of the bores extends in the rotation direction of the wheel.
8. Separator according to claim 6 or 7,
   characterized in that,
   with respect to a Cartesian coordinate system having the origin on the cylinder's longitudinal axis, the tilt angle is in the range between 30° and 60°, preferably between 40° and 50°.
9. Separator according to claim 2, 5, 6 or 7,
   characterized in that
   the respective bores are arranged to be staggered from one another in the circumferential direction of adjacent bore rows.
10. Separator according to any one of claims 2 to 9,
    characterized in that
    the drive-side end of the cylindrical body exhibits a surrounding chamfer (10).
11. Separator according to any one of claims 2 to 10,
    characterized in that
    the cylindrical body is formed of a plastic, in particular a hard polymer material.
12. Separator according to claim 11,
    characterized in that
    the cylindrical body comprises a metal core insert.
13. Separator according to claim 1,
    characterized in that
    the intake position is oriented to be tangentially extending to the separating chamber.

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