DE102004053530B4 - Classifying wheel for a device for separating dusty, fibrous or granular goods - Google Patents

Abstract

classifier for one Device for separating dust-like, fibrous or grainy Goods after the Sink rate under the influence of grain shape, grain size and density, consisting of a substantially cylindrical body with a concentric core or pin for receiving a drive shaft, a variety over the cylinder circumference distributed flow openings and a fine material outlet, the cylindrical body consists of a monolithic block, between the flow openings Webs (7) remain in the cylinder jacket (5) and the flow openings formed as a plurality of radially oriented holes (9) are the bore longitudinal axes at an angle at an angle are arranged extending and the imaginary extended bore longitudinal axes outside the cylinder longitudinal axis (2) cutting, wherein the cylinder jacket wall thickness in the range of 0.1 to 0.4, preferably 0.125 to 0.3 times the cylinder outer diameter and based on a cartesian coordinate system of origin on the cylinder longitudinal axis (2) the skew angle in the range between 40 ° and 50 ° and the respective holes (9) in the circumferential direction of adjacent Bore rows are offset from one another.

Description

The The invention relates to a classifying wheel for a device for separation dusty, fibrous or grainy Goods after the rate of descent under the influence of grain shape, grain size and density, consisting of a substantially cylindrical body with a concentric core or pin for receiving a drive shaft, a variety over the cylinder circumference distributed flow openings and a fine material outlet.

winnowing presents itself as a process for separating dust-like, grained or fibrous goods, the separation according to the rate of descent under the influence of grain shape, Grain size and density he follows.

One quality criterion an air classifier is the separating effect, where possible all particles larger than the separating boundary are, into the coarse material and smaller particles into the fines promoted become.

For air classifier come so-called sifter wheels from e.g. Steel or ceramics are used, with the possibility also There are 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.

Between the over Spacers spaced apart from each other is a plate Variety of conveyor blades, which for the necessary flow of goods in conjunction with the aforementioned drive to care. The shovels associated with the abandoned good have to extremely durable especially at high speeds and be abrasion resistant to a technologically meaningful life of the respective Classifier wheel to reach.

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 mounted adjustable 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.

From the DD 290 318 A7 For example, a classifier wheel for a countercurrent centrifugal air classifier with forced swirling flow is known for separating a stock to a coarse and a fine fraction. The local Sichterrad has a cylindrical shape and has on the lateral surface numerous, to the interior of the Sichterrades through holes. Specifically, the holes are evenly distributed over the entire surface of the Sichterrades arranged. In a first local embodiment, the holes are all arranged in the radial planes of the classifier wheel, ie have no inclination. In a further embodiment, the cylindrical bores are at an angle of approximately 20 ° to the radial planes of the classifier wheel. Likewise is from the DD 290 318 A7 an angular position of the holes in a range of 10 ° to the radial direction of the classifying wheel already known. This 10 ° embodiment reveals that it was considered that, when tilted in relation to the radial direction, it should be kept smaller than 45 °, preferably 10 °, in any case.

The DE 41 40 656 C1 shows a Sichterrad for blower air classifier with slit-shaped openings, but which have no inclination.

It However, it has been found that known sizing wheels in terms the selectivity, the yield of fines and the life still not all requirements suffice for various applications. In particular occurs at usual Sifter wheels in particular at the fines exit a very high, hardly avoidable wear on, with the consequence that one more or less frequent Changing the Sichterrads and thus a production interruption becomes necessary.

From the foregoing, it is therefore an object of the invention to provide a further developed Sichterrad for a device for separating dusty, fibrous or granular goods after the rate of descent under the influence of grain shape, grain size and density, this Sichterrad compared to the prior art longer life by a smoother wear, finer To ensure separation limits and even finer finished goods, in particular the latter quality criterion is to be ensured by the use of higher speeds.

The solution The object of the invention is achieved with a Sichterrad according to the feature combination according to claim 1, wherein the dependent claims expedient refinements and developments include.

at the proposed Sichterrad is of a known, essentially cylindrical body assumed that the cylindrical body has a concentric core or pin for receiving a drive shaft, preferably for a having a motor drive and a plurality distributed over the circumference of the cylinder flow openings and has a fines exit.

According to the invention the cylindrical body from a monolithic block, the cylinder shell thickness in comparison chosen to be much larger in 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 for a sufficient Strength against Wear worry will be carried. The flow openings are formed as a plurality of radially oriented holes.

The bore longitudinal axes are slanted at an angle arranged extending, with the imaginary extended bore longitudinal axes outside the cylinder longitudinal axis to cut.

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

Based on a Cartesian coordinate system originating on the cylinder longitudinal axis is the skew angle the holes in the range 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 is usually inclined or can be executed as a circular arc section.

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

Farther comprises the cylindrical body a metal core insert which in turn receives a drive shaft serves.

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

With Use of the classifier wheel according to the invention it has been shown that by the multitude of flow openings, especially holes, the flowing air or the product-air mixture very much evenly over the full area of the Rades distributed. This results in a very uniform and low overall load on the wheel, i. the wheel surface, where in the quintessence, longer ones Stand times arise.

By the arrangement of holes in the monolithic body in an area ratio bore to remaining ridges of substantially about 1: 1 arise higher Strengths of the impeller, whereby higher peripheral speeds of ≥ 60 m / sec possible are, i. it can even finer finished goods be achieved when using the Sichterrads in an air classifier.

All in all leads the Use of the presented Sichterrads for a better selectivity, a higher Fines yield, which in turn is available low-fines coarse material.

The Invention will be described below with reference to an embodiment and below With the help of figures closer explained become.

in this connection demonstrate:

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

2 a representation of the hole Sichterrads after 1 with recognizable obliquely oriented offset holes, circumferentially distributed over the cylinder jacket.

The classifier wheels shown in the embodiment have a substantially cylindrical shape with a bottom portion which is designed flange-like and with respect to the cylinder longitudinal axis 2 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 on, which serves the fines exit.

From the illustrations it is clear that, in contrast to the known prior art, the thickness or thickness of the cylinder jacket 5 is very large and, for example, in the range to 0.1 to 0.4, preferably 0.125 to 0.3 times the cylinder outside diameter is.

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

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

In the embodiment according to the drawings after 1 and 2 is assumed by a hole-Sichterrad, which is a floor area 1 , a cylindrical longitudinal axis 2 , a steel core insert 3 and an opening section 4 having.

In the cylinder jacket 5 are hole-like holes 9 brought in.

The longitudinal axes of the holes 9 run at a predetermined angle (see 1 , left part of the picture).

Accordingly, the bore longitudinal axes of the holes 9 arranged obliquely at an angle, wherein the imaginary extended bore longitudinal axes outside the cylinder longitudinal axis 2 to cut.

The oblique orientation of the holes 9 runs preferably in the direction of rotation of the Sichterrads (see arrow).

Based on a Cartesian coordinate system originating on the cylinder longitudinal axis 2 is the skew angle of the holes 9 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 1 , right part of picture becomes clear.

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

in the Compared to standard classifying wheels occurs in the embodiments according to the invention, in particular a lesser one for those with a large number of holes or holes and circumferentially even wear on, so that longer life result.

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 in the wheel are within the scope of the theory of the invention freely selectable and can be selected according to the selected material types of the wheel realized by machining processes.

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

Of the Misfire content in a standard wheel is in the range between 33% and 34%; in a pinwheel according to the invention, however, only in Range between 30% and 32%. Despite much finer separation results In the use of the doctrine of invention, a better proportion of defective grain.

at further attempts with sand was a significantly better selectivity and thus detected fines yield. The false grain share was here for a standard wheel in the range between 15% and 16%, the pinwheel according to the invention at about 5%.

1

floor area

2

cylinder longitudinal axis

3

Steel core insert

4

opening section

5

cylinder surface

7

web

9

drilling

10

chamfer

Claims (5)

Classifying wheel for a device for separating dusty, fibrous or granular goods at the rate of descent under the influence of grain shape, grain size and density, consisting of a substantially cylindrical body with a concentric core or pin for receiving a drive shaft, a plurality of flow openings distributed over the circumference of the cylinder and a fines exit, wherein the cylindrical body consists of a monolithic block, between the flow openings webs ( 7 ) in the cylinder jacket ( 5 ) and the flow openings as a plurality of radially oriented holes ( 9 ) are formed, the bore longitudinal axes are arranged obliquely at an angle and the ge thought elongated bore longitudinal axes outside the cylinder longitudinal axis ( 2 ), wherein the cylinder jacket wall thickness in the range of 0.1 to 0.4, preferably 0.125 to 0.3 times the cylinder outer diameter and based on a Cartesian coordinate system originating on the cylinder longitudinal axis ( 2 ) the skew angle is in the range between 40 ° and 50 ° and the respective holes ( 9 ) are arranged offset in the circumferential direction of adjacent rows of holes offset from one another. Classifying wheel according to Claim 1, characterized in that the oblique orientation of the bores ( 9 ) runs in the direction of rotation of the classifier wheel. Classifying wheel according to one of the preceding claims, characterized in that at the drive end, the cylindrical body has a circumferential chamfer ( 10 ) having. Classifier wheel according to one of the preceding claims, characterized characterized in that cylindrical body from a plastic, in particular hard polymer material. Classifying wheel according to Claim 4, characterized that the cylindrical body a metal core insert.