EP2150330B1 - Stirring member for stirring abrasive media - Google Patents

Description

The invention is concerned with a radially ferderuchen stirrer, which is particularly intended for abrasive media. When agitating abrasive media, such as suspensions with high solids loading, which occur for example in the ore processing, such as oxidation autoclave for gold and copper extraction occurs due to abrasion increased wear, resulting in that the agitator only relatively short life has and then needs to be replaced.

It has also been attempted to provide coatings to reduce the abrasion on the stirrers with abrasion resistant materials, which may be, for example, hard metals, metal carbides or the like. Such coatings are not only extremely expensive, but the application of coatings may also partially lead to the weakening of the substrate, resulting in further difficulties. Especially in wet chemical processes in the ore processing extreme corrosive conditions are given, which make it necessary to use for the substrate particularly resistant materials, such as titanium materials. In particular, it has been found that such, the wear resistance-improving coatings are often not chemically resistant enough and can be removed by corrosion.

So-called disk stirrers are known as radially conveying stirrers, which comprise a carrier disk to which a plurality of stirrer blades are connected, which are connected perpendicularly to the carrier disk and radially thereto. The carrier disc is aligned horizontally in such a disc stirrer and the stirrer blades are connected to the carrier disc over approximately half the blade height, as in FIG Fig. 1 the drawing shown. Disc stirrer of this type may have a different number of stirrer blades and / or the stirrer blades may have different sized blade surfaces.

US 2005/007874 A1 shows a stirrer with which a local shear is to be reduced with respect to the product, and thus a low-shear stirrer. The stirrer is attached via a carrier to a drive shaft and has stirrer blades, which are in particular folded. The stirrer is described by the employment of Rührorganblätter as axial conveyor, which causes the homogenizing and suspending effect of this stirring element.

DE 203 13 722 U1 refers to the homogenization / mixing of liquids (such as paints). Although solids in the form of pigments are mentioned, they will not be discussed further. The main advantage over existing similar systems for mixing colors is the ease of cleanability. In particular, a stirrer with a (carrier) disc and a shaft (a drive shaft) is shown, wherein agitator blades are spaced from each other and tilted inserted in the disc.

WO 2007/013415 A and the corresponding European patent application EP 1 911 511 A1 show an axially conveying stirrer, wherein agitator blades are arranged on a drive shaft. The stirrer is used to disperse a product, which means that a shear is introduced into the product. Therefore, the stirrer also has very small leaf surfaces.

US 3,526,467 A refers to the structural design of a stirrer. The stirrer is fixed to the stirrer shaft in a hub-to-hub configuration. A simple introduction into the stirred tank, a simple cleanability, a maximum corrosion resistance and a good coatability of the stirring element are described as advantages of this structural design.

The document published after the priority date of the present application WO 2008/083673 A2 shows a stirring arrangement with stirrer and gassing. This stirring arrangement is intended to prevent flooding of the stirring element with gas.

DE 34 46 741 A1 describes a circulation device which is intended to prevent solids from segregating or settling in a suspension. This is achieved by a method that generates circular horizontal flow movements. This process creates a uniform velocity field in the container.

US 6 637 926 B1 describes an apparatus for mixing two fluids. Figures 5a to 5f show typical stirring elements which can be used in the apparatus.

GB 2 034 187 A describes a glass-coated stirrer having a constant blade radius, wherein the geometry of the blade has been changed to allow introduction into a container through a manhole smaller than the agitator orifice diameter.

JP 57 059625 A describes an energy saving, ie an increase in the pumping rate of the stirrer at a given stirring power, as the target.

US 3 470 265 A refers to the preparation of liquid-liquid dispersions in which a particular drop size (distribution) is the target size.

EP 1 776 999 A1 describes a stirrer that can be manufactured cost-effectively due to its construction. Replaceable sheets of various shapes can be attached to a carrier.

WO 2006/057560 A1 describes a stirring member for producing a liquid spray film. This is due, inter alia, to the fact that the specially shaped upper part of the stirrer blade is mounted outside the liquid. The advantage of the special geometry of the stirring element is that the mass transfer of air oxygen into water is increased by the drops of water thrown into the air space.

DE 10 2005 058724 A1 relates to a method for producing a chemical substance (tertiary amine). It is mentioned that various standard stirrers can be used in this process. DE 10 2005 058724 A1 refers to certain operating conditions that are set with the stirrers can - as they could be adjusted with any other stirring device.

The invention aims to provide a radially conveying stirrer, in particular for abrasive media, with a carrier disk on which perpendicular to the carrier disk and radially extending stirrer blades are connected in the outward direction and which has a hub for receiving a stirrer shaft, which abrasionsarm is to be interpreted and has a longer life in a proper use.

According to the invention, for this purpose, a radially conveying stirrer, in particular for abrasive media, provided with the features of claim 1.

In the stirring element according to the invention, therefore, the agitator geometry in the region of the carrier disk, the stirring blade, the Rührorganblattanbindung and the Rührorgannabe or the like is chosen and tuned so that even with abrasive media with high solids loadings and with large Rührleistungseinträgen to reduce abrasion As well as corresponding high peripheral speeds, the wear phenomena can be significantly reduced by abrasion or can even be completely ruled out. In the stirring element according to the invention thus the Rührorgangeometrie is changed and optimized to obtain stirrers, which have a prolonged life, thereby reducing maintenance and replacement intervals of the stirring elements and thereby significantly reduce system downtime.

Further preferred embodiments are specified in claims 2 to 8.

In the case of the radially conveying stirring element according to the invention, such a configuration is provided to the abrasion-endangered areas, such as the sides of the agitator leaves which are facing away from the flow and / or to the areas of the blade connections on the carrier plate, by means of geometric means a largely vortex-separation-free configuration will, in particular to reduce impact and Gleitverschleißerscheinungen the intended use of such Rührorgans, as a radial conveyor in the form of a Scheibenrührers sustainable to improve the service life of such a stirring without time-consuming and costly additional measures on the stirring element, such as coatings and the like to make , In the invention, in particular, such measures are proposed which allow an original reduction of the unfavorable with regard to wear behavior vortex shedding and provide more favorable Blattumströmungsverhältnisse without affecting the basic performance of such a stirring member. By a correspondingly changed shaping of the stirring element, therefore, the wear mechanism can be suppressed in the invention so that an agitator with extended service life is obtained and a considerable potential for savings in maintenance and plant downtimes can be realized. Of course, should be taken in such a geometry-improved stirrer no loss of performance in purchasing.

Figur 1

zeigt eine übliche Ausführungsform eines Rührorgans in Form eines radial fördernden Scheibenrührers;

Figur 2

zeigt eine Ausgestaltungsform einer Rührorganform mit einer winket Anstellung der Ruhrorganblatter,

Figur 3

zeigt ein Rührorgan mit abgeändeter Blattform der Rührorganblätter;

Figur 4

zeigt eine bevorzugte Ausführungsform mit einer geänderten Blattform und einer Anstellung der Rührorganblätter in radialer Richtung;

Figur 5

zeigt ein Rührorgan mit abgeänderter Anbindung der Rührorganblätter an der Trägerscheibe;

Figur 6

zeigt ein Rührorgan mit einer geänderten Ausgestaltungsform einer Trägerscheibe;

Figur 7

zeigt ein Rührorgan mit einer abgewandelten Trägerscheibenkonstruktion;

Figur 8

zeigt ein Rührorgan mit teilweise abgeänderter Trägerscheibe und optimierten Anbindungsstellen der Rührorganblätter an der Trägerscheibe; und

Figur 9

zeigt ein Rührorgan mit zusätzlichen Maßnahmen zur Verbesserung der Umströmung der Rührorganblätter an der Blattinnenkante.

Tecknik prior art and the invention will be explained in more detail below with reference to the accompanying drawings. In the drawing, the corresponding embodiments of the stirring elements are each illustrated in a figure in a plan view and underneath in a side view. In the drawing:

FIG. 1

shows a conventional embodiment of a stirring element in the form of a radially conveying Scheibenrührers;

FIG. 2

shows an embodiment of a Rührorganform with a winket employment of Ruhrorganblatter,

FIG. 3

shows an agitator with modified leaf shape of Rührorganblätter;

FIG. 4

shows a preferred embodiment with a modified blade shape and a position of the Rührorganblätter in the radial direction;

FIG. 5

shows a stirrer with a modified connection of the stirrer blades on the carrier disc;

FIG. 6

shows an agitator with a modified embodiment of a carrier disk;

FIG. 7

shows a stirrer with a modified carrier disk construction;

FIG. 8

shows a stirrer with a partially modified carrier disk and optimized attachment sites of Rührorganblätter on the carrier disk; and

FIG. 9

shows a stirrer with additional measures to improve the flow around the Rührorganblätter at the blade inner edge.

In the figures of the drawings, in each case the direction of rotation of the agitator shaft and thus of the carrier disk is entered with an arrow.

Furthermore, in the figures of the drawings, the same or similar parts are provided as far as possible with matching reference numerals.

In FIG. 1 is a schematic view of an example of a radially promoting stirrer, a so-called Scheibenrührers of the conventional design illustrates. The stirrer, generally designated 1, comprises a preferably horizontally arranged support disk 2, to which a plurality of stirrer blades 3 are attached perpendicular to this and substantially radially. In the illustrated example, the agitator blades 3 are straight and the agitator blades 3 have a rectangular shape. The agitator blades 3 are arranged symmetrically on the circumference of the carrier disc 2. Each rectangular blade body 3 has a height h and a length I. In the example shown, the Rührorganblätter 3 are attached to the support plate 2 in about half the blade height h. Such a stirring element 1 has a good dispersing effect, in particular in gassing, and generates a primarily radial flow direction with a corresponding pumping efficiency and a strong Gasdispergiervermögen.

The FIGS. 2 to 9 show geometric modifications of a radially conveying stirrer. Important in these geometrically modified design forms of the agitation system 1 is the fact that neither the primary flow direction, nor the pumping efficiency, the power input or the Gasdispergiervermögen are adversely affected in all the modifications.

In the design form of the stirring member 1a according to FIG. 2 the agitator blades 3a to the radial are made at an angle β , which is in a range of about 10 ° to 60 °, preferably in a range of about 20 ° to 50 °. As a result of this radial adjustment of the agitator blades 3a, vortex shedding can be prevented, in particular on the trailing side of the agitator blades 3, so that more favorable flow conditions in the agitator blade 3a and its connection to the carrier disc 2a are obtained in the agitator 1a.

In the design form of the stirrer 1b after FIG. 3 the leaf shape of the agitator leaves 3b is optimized and changed accordingly, as shown in particular in the lower illustration in FIG. 3 can be seen. By appropriate design of the stirrer blades 3b thus vortex shedding can be prevented and obtained favorable Umströmungsverhältnisse to the stirrer blades 3b and the associated connection areas on the support plate 2b.

In FIG. 4 is an embodiment of a stirring member 1c shown, in which the agitator blades 3c similar to at FIG. 2 at an angle β to the radial are employed, for better sheet flow around and to prevent vortex shedding the Rührorganblätter 3c at the connection region to the support plate 2c have a radius R, which is in a range R = (0.1 - 1.0) x Rührorgandurchmesser , The agitator orifice diameter is the largest outer diameter of the agitator 1c including the outer ends of the agitator blades 3c.

Based on FIGS. 5 to 7 Embodiments of stirrers 1 d to 1f are explained, in which the respective agitator sheets 3d to 3f are fixed on one side to the associated carrier disk 2d to 2f. The respective carrier disk 2d to 2f forms a cover for the attached agitator blades 3d to 3f, whereby a sheet flow around the agitator blades 3d to 3f is prevented. at the embodiment according to FIG. 5 are radially arranged Rührorganblätter 3d, which have substantially in the radial direction, attached to an end face of the support plate 2d.

In the design form of the stirrer 1e after FIG. 6 At the same time, the shape and in particular the outer contour of the carrier disc 2e is changed and adapted, and at the same time the agitator blades 3e are connected on one side substantially radially to the carrier disc 2e. This gives similarly advantageous effects as in the embodiment according to FIG. 5 ,

In the embodiment according to FIG. 7 the stirring element 1f comprises a plurality of carrier disk parts 2f and 2f, which together form the carrier disk together. These two carrier disk parts 2f and 2f each form the outer contour of the stirring member 1f viewed in the axial direction, and the agitator blades 3f are connected and covered on both sides by the carrier disk parts 2f and 2f. This also makes it possible to effectively avoid wear-generating flow around the agitator blades 3f.

The FIGS. 5 to 7 Thus show embodiments of stirring members 1d to 1f, in which on the one hand the shape of the support disk 2e (in FIG. 6 or the number of carrier disk parts 2f, 2f (see FIG FIG. 7 ) can be varied.

In FIG. 8 an embodiment variant of a stirring element 1g is shown, in which the geometry and the size of the carrier disc 2g are changed. On the side of the agitator blades 3g facing away from the flow, 2g recesses 10 are provided on the carrier disk, whereby the attack surfaces for the abrasion are reduced.

How out FIG. 9 can be seen, which shows a further embodiment variant of a stirring member 1h, wing-shaped elements 11 are attached to the inner edge of the Rührorganblätter 3h, which extend substantially perpendicular to the radial extent of the Rührorganblätter 3h and have a corresponding extent b. With the help of these wing-shaped elements 11, a flow around the agitator blades 3h is prevented with negative vortex formation phenomena.

Claims (8)

1. Radially conveying stirrer device intended for use with abrasive media, having a carrier wheel (2a), in relation to which outwardly projecting radially rotating stirrer blades (3a) are attached vertically, and having a hub into which a stirrer shaft can be fitted, characterised in that the stirrer blades (3a) are set at an angle ß of 10° to 60° in relation to the radial axis and the respective stirrer blade (3c) in the vicinity of the blade attachment to the carrier wheel (2c) has a radius (R) facing in the direction of the flow, having a value of R = (0.1 - 1.0) x the diameter of the stirrer device, so that the sides of the stirrer blades (3a, 3c) facing away from the flow and/or the area of the blade connection of the carrier wheel (2a, 2c) are largely free of the radial flow effect.
2. Radially conveying stirrer device according to claim 1 above, characterised in that the stirrer blades (3a) are set at an angle ß of between 20° and 50° in relation to the radial axis.
3. Radially conveying stirrer device according to either of the preceding claims, characterised in that one side of the stirrer blades (3d to 3f) is attached to the carrier wheel (2d to 2f).
4. Radially conveying stirrer device according to any of the preceding claims, characterised in that an outwardly projecting outer contour of the carrier wheel (2e) is formed in each case at the point where the stirrer blades (3e) are attached corresponding to the outward projection of the radially moving stirrer blades (3e).
5. Radially conveying stirrer device according to any of the preceding claims, characterised in that the carrier wheel (2f, 2f¹) comprises a number of carrier wheel segments (2f, 2f¹).
6. Radially conveying stirrer device according to any of the preceding claims, characterised in that the carrier wheel (2g) has a recess (10) on the side of the stirrer blades (3g) facing away from the flow.
7. Radially conveying stirrer device according to any of the preceding claims, characterised in that wing-shaped elements (11) are arranged on the inside of the stirrer blades (3h).
8. Radially conveying stirrer device according to any of the preceding claims, characterised in that those areas of the stirrer blade (3a to 3h) that are exposed to abrasion are fully or at least partially coated with an abrasion-resistant material.

Images