EP1871514A1

EP1871514A1 - Mixing blade provided with a removable wearable element

Info

Publication number: EP1871514A1
Application number: EP06725387A
Authority: EP
Inventors: Andreas Seiler; Wolfgang WÖRNER; Klaus Ahke
Original assignee: Maschinenfabrik Gustav Eirich GmbH and Co KG
Current assignee: Maschinenfabrik Gustav Eirich GmbH and Co KG
Priority date: 2005-04-22
Filing date: 2006-03-29
Publication date: 2008-01-02
Anticipated expiration: 2026-03-29
Also published as: CA2602970C; US20090219782A1; DE502006007038D1; DK1871514T3; BRPI0609180A2; US8235583B2; KR20080012858A; RU2007142846A; PL1871514T3; ZA200708851B; JP4891989B2; RU2392043C2; CN101163539B; ATE468910T1; ES2346241T3; WO2006111455A1; KR101274734B1; DE102005019010A1; EP1871514B1; MX2007012943A

Abstract

The invention relates to a mixing blade (6) consisting, of a base part (15) fixable to a shaft and a removable wearable element (12). The aim of said invention is to develop a more economical mixing blade. For this purpose, the wearable element (12) and the base part (15) overlap on at least 30% of the base part length and define different cross-sections of the mixing blade (6) in said area.

Description

Maschinenfabrik Gustav Eirich GmbH & Co. KG

Mixing blades with detachable wear element

The present invention relates to a mixing blade, comprising a base part which can be fastened to a shaft and a detachable wearing element.

A corresponding mixing blade is known from German Utility Model No. 203 07 420.3 and the corresponding EP 1 477 218 A. In the known mixing blade, the tip of the mixing blade is formed as a replacement element and has a matching with the subsequent section of the mixing blade cross section (perpendicular to the longitudinal direction of the mixing blade).

Such mixing blades are intended for use in mixers in which granular, abrasive materials are processed.

In the prior art mixers are known which have one or more, arranged perpendicular to the mixing vessel bottom mixer shafts, which are provided with arranged in several planes, radially extending mixing blades. The mixing vanes are generally of substantially rectangular cross-section, which cross-sectional shape is sometimes also tapered towards the front edge of the mixing blade, so that the mixing vanes have the overall shape of a flat, one-sided rectangular trapezium. The leading edge of the mixing blades is the front edge in the direction of rotation of the corresponding rotor, which comes into engagement with the material to be mixed with the rotor rotating in front of the remaining parts of the mixing blade. To achieve optimum mixing results, the leading edge is often chamfered like a knife to mitzugeben the Aufbereitungsgut at the same time an axial movement component during penetration. The mixing blade body is generally made in one piece and is made of a comparatively soft material, e.g. Mild steel, manufactured. To protect against wear, the leading outer edges and the extreme end of the mixing blade and their immediate environment are protected by wear-resistant steel, a brazed carbide plating or armor. The armor preferably applied by application welding may be e.g. made of a hard, wear-resistant coating, such as a tungsten carbide-containing alloy. The thickness of the armor is adapted to the effect on the mixing blades, locally different wear effects.

In the known mixing blades is considered disadvantageous that they are often interchangeable only as a whole. The replacement of the wear-resistant coating or armor is usually - -

very expensive and can not be done in the installed state. For reprocessing, the mixing blades must therefore be completely removed.

A mixing blade is already known from the above-mentioned German utility model, in which only the tip of the mixing blade can be exchanged separately from the rest of the mixing blade, whereby it should be taken into account that the tips of such mixing blades are the most heavily used due to the higher rotational speed Parts of a mixing blade belong.

Detachable parts of mixing tools are also known from various other documents. DE 200 04 488 describes a mixer blade fastened to a support arm projecting radially from a mixer shaft, in particular a bottom blade for concrete mixers, with a detachable blade nose.

As already mentioned, the mixing vanes are subject to wear during operation by the material flows flowing at different speeds above it. They are subject to a very different wear over the length of wear and wear preferably at its outer end, since there prevails the highest peripheral speed. In a knife-like beveled rectangular cross-section, however, next to the outer end of the mixing blade and the leading edge is exposed to a particularly high wear. This is especially true when coarse-grained products, such as broken rocks, are included in the mixture. Upon impact of such coarse-grained components on the front edge of the mixing tool, the narrower it is formed, the greater the weight of the individual coarse-grained components and the harder these constituents are.

Due to the adjoining the edge, sloping surface of the wing, the product is deflected accordingly up or down. The adjoining the slope region of the cross section is significantly less affected by wear than the leading edge including the beveled surfaces.

Once the armor at the leading edge of the mixing blades is worn or worn away, the soft base material underneath is all the more easily worn and subject to a very strong abrasion, which also partially covers areas of still existing armor. This can cause whole parts of the wear protection and the body break out, which can lead to damage or even stoppages to downstream machines.

In operation, therefore, the complete mixing blades, which are usually releasably attached to the central mixer shaft, must be replaced at regular intervals, even if only small parts - -

of the mixing blade are worn down to the base material and the wear protection in other places is still sufficiently strong.

A mixing blade with detachable tail solves the problem only partially, as it may well be that occasionally radially located within the releasable end portions of the mixing blade have experienced a greater wear. In such a case, however, the entire mixing blade must be replaced. Furthermore, at the joint by permanent impact stress by very coarse-grained products at the top of the mixing blade a gap arise., In which fine product clamped and leads to the elongation of the screw connection up to their failure. Also, when using a releasable end made of solid carbide and very high peripheral speeds due to the large centrifugal forces on the mixing tool to a strong elongation of the fasteners come up to their failure.

A significant extension of the tail, which would cover a significantly larger portion of the mixing blade than just the tip, is also not a satisfactory solution to the problem, because then the replacement would be only relatively small replacement of the tail against a complete replacement of the mixing blade.

Compared to this prior art, the present invention seeks to provide a mixing blade of the type mentioned, which has an overall improved economy.

This object is achieved by a mixing blade, which is in addition to the features mentioned above still characterized in that the wear element (13) and the base (15) overlap over at least 30% of the length of the base and in this overlap portion different areas of the cross section of the Define mixing blade (6).

The length of the base is measured from its radially inner, to be fastened to the shaft or corresponding support members end to the radially outer tip.

The fact that the wear element and the base have different cross sections and overlap in the longitudinal direction of the base over a larger portion of at least 30%, one can exchange a larger portion of the mixing blade, without causing the entire, remaining portion of the mixing blade over the full Cross section must be removed or replaced. - -

According to the preferred embodiment, the wear element forms at least the radially outer third, preferably at least the radially outer half of the front edge of the mixing blade in the running direction.

In this case, the wear element next to the leading edge and the entire tip or the entire end of the mixing blade form and thereby cover the cross section of the tip of the base either completely or at least partially.

This embodiment makes it possible to replace the worn parts of a mixing blade, which usually includes the tail and the radially outer half of the leading edge, as needed, without the other parts, namely the main body of the mixing blade, must be replaced. The replacement of the wear elements can thus be limited to the parts or areas that are actually exposed to increased wear and the addition of the tail and the tip of the mixing blade and its leading edge at least in the radially outer ßere 30% of the (radial) length of the mixer.

In this case, an embodiment is particularly preferred, in which the wear element is formed in several parts, and for example consists of a leading edge portion and an end portion or a tip of the mixing blade, which are separately attached to the base of the mixing blade.

According to a first embodiment, the wear element in the plan view has a rectangular shape and fills a corresponding rectangular recess in the base part, wherein (partially to avoid notch loads), the corner areas are more or less rounded. The wear element forms e.g. in plan view, approximately the front half or the front third (respectively measured from the front edge) of the entire mixing blade, while the rear part of a mixing blade is formed by the main body, which may be made of a less hard, but easier to work material.

Furthermore, an embodiment of the invention is preferred in which the cross section of the wear element is tapered towards the front edge. This knife-like design with sloping ramp surfaces contributes to a particularly good mixing due to the vertical movement of the mix produced thereby, the sharp leading edges also provide for a comminution of coarse-grained ingredients or agglomerates. With sharp leading edges, however, embodiments are also meant here in which the front edge of the mixing blade is not "razor-sharp" in the narrower sense, but rather the edge is significantly narrower than the maximum thickness of the mixing blade (measured in the direction of the axis of the associated rotor) Thus, for example, only 1/4 to 1/20 (or less) of this thickness. - -

More preferably, the wear element has in cross-section the shape of a rectangular trapezium, i. a trapezoid having a right-angled end and a tip tapered at a relatively small angle, wherein the tip defined thereby may also be somewhat bevelled or rounded off.

The connection between the wear element and base preferably takes place via bolts from the back of the base forth through holes in the base, the bolts engage in threaded holes in the back of the wear element. The threaded holes can also be inserted or soldered threaded bushings.

According to an alternative embodiment, the wear element defining the major part of the leading edge has a cross section decreasing from the tip of the blade in the direction of its radially inner end, while the base part has a correspondingly increasing cross section in the same area. In this case, the cross section takes substantially only in the direction of the width of the mixing blade, i. in the direction measured from the front edge to the back direction. With continuously decreasing cross-section at the same rate, the top plan view then yields the shape of a right-angled triangle with a relatively acute angle for the wear element. The acute angle end is closer to the radially inner end of the mixing blade, i. towards the wave. In this way, an even larger part of the harder and more expensive wear material can be saved, since the wear to the radially inner portions of the mixing blade towards decreases more and there correspondingly less wear material is needed.

A modification to this, but based essentially on the same basic idea, is a shape that appears in the plan view in approximately Z-shaped or in which, starting from the triangular shape just described, the two vertices of the triangle (with angles smaller than 90 °) are cut off. Another variant has approximately an L-shape, wherein, however, the longer, the front edge of the mixing blade forming L-leg widened continuously in the direction of the second leg of the L. A third modification of the triangular basic shape (narrow wear body toward the center, which becomes progressively wider towards the outside) has a curved joint, thus replacing the hypotenuse of the triangular shape described first with a concave (or convex) arc.

Further advantages, features and possible applications of the present invention will become apparent from the following description of preferred embodiments and the associated figures. Show it: - -

1 shows a rotating mixing vessel with eccentrically arranged mixer shaft and stationary wall-floor scraper,

FIG. 2 shows a plan view of a mixing blade with detachable wear element,

FIG. 3 shows a side view of a mixing blade with a detachable wearing element,

FIG. 4 shows a plan view of a mixing blade with detachable triangular wear element and hard metal-clad base body,

5 is a plan view of a mixing blade with detachable wear element with excess,

FIG. 6 shows a side view of a mixing blade with excess wear element,

FIG. 7 shows a side view of a mixing blade with a wear element resting on a shelf,

8 is a plan view of a mixing blade with detachable L-shaped wear element with excess,

Figure 9 is a plan view of a mixing blade with releasable wear element and releasable end piece, and

FFiigguurr 1100 is an isometric view of a cut-open mixing blade with detachable wear edge and detachable corner piece.

FIG. 1 shows a mixer 1, which in the preferred embodiment is provided with a rotating mixing container 2, consisting of a round, flat mixer bottom 3 and a cylindrical mixer wall 4. The mixer further has an eccentrically arranged to the mixing vessel center, overhung, until just above the mixer bottom reaching rotor 5, which is arranged in several planes, radially extending mixing blades 6 carries with detachable wear element. The mixing container 2 and the rotor 5 are rotated by drives (not shown) in rotation. The cylindrical wall 4 and the mixer bottom 3 are stripped off by a stationary, combined wall bottom tool 7. The emptying of the mixing container 2 takes place via the central bottom emptying opening 8.

The rotor 5 consists of a polygonal shaft (not shown), on which a plurality of tool holders 9 are arranged one above the other displaced. In grooves 10 of the tool holder, the mixing blades 6 are suspended in pins (not shown) by means of the bore 11. The column of tool holders 10 with mixing blades 6 is clamped by a suitable releasable connection for operation. In an alternative embodiment, the mixing vanes 6 are integrally connected to the rotor 5. Also, it is not absolutely necessary for the effectiveness of the invention that the mixing container 2 rotates and the rotor 5 is arranged eccentrically in the mixing container 2. In addition to the use of a stationary mixing container 2, in which rotates one or more rotates about their vertical or inclined axis rotors on a planetary orbit about a center of the mixing vessel centrally arranged sun, the rotor 5 can also be arranged centrally with the mixing blades according to the invention in a stationary mixing container. Also, the Mischflü- - -

Gel radially from a horizontally extending rotor, which is arranged in a horizontal stationary mixing container, are used.

The mixing blade 6 in FIG. 2 consists of an approximately L-shaped main body 15 with a right-angled recess into which a corresponding, right-angled wear element 12 is suitably inserted. Here too, the corner of the wear element located in the joining area, as well as the corresponding corner of the recess, is preferably strongly rounded off. Thus, the mixing blade also has the shape of an oblong rectangle overall in plan view from above, wherein the largest part of the front edge is defined by the wear element 12 approximately to the longitudinal center of the mixing blade 6. The wear element 12 has, as can be seen, inter alia, in the front view according to Figure 3, over most of its length, the cross section of a rectangular trapezoid whose tip is slightly cut. Conversely, one could define the wear element as a parallelepiped having on one side (optionally on both sides) a significant bevel 13, so that there is a relatively narrow, knife-like leading edge for the wear element, and the bevel 13 a ramp surface for mixing Material forms.

In Figure 2 can be seen to the radially inner end towards a transition region in which the chamfer 13 increasingly smaller, so that the cross section of the wear member 12 at its inner end again assumes the shape of a rectangle, which also rectangular cross section of the body 15 to a longer, narrow rectangle added. The inner end of the base 15 has the same narrow rectangular cross section that the wear element 12 and the base 15 (apart from the chamfer 13) together form.

In the width of the mixing blade, the wear element accounts for about 20% bi 80%, preferably 30% to 70% and more preferably between 50% and 60% of the total width.

The detachable wear element 12 and the main body 15 of the mixing blade 6 are formed as separate components. As FIGS. 2 to 10 make clear, the components are detachably connected to one another by suitable fastening means. The connection must be able to transfer the forces acting on the wear element 12 from the mix to the base body 15 of the mixing blade 6. In addition, the wear element 12 must be secured against rotation relative to the main body 15 of the mixing blade 6.

The detachable connection and securing against rotation can be achieved in various ways, for example by two or more screw connections 14 (FIG. 2), by one or more centering pins in conjunction with a screw connection or by an overlap of wear and tear. - -

Element and body of the mixing blade (Fig. 7, Fig. 8), as well as with at least one releasable connection element.

In the variant of Figure 4, the releasable wear element in the plan view from above has a substantially triangular shape. In this case, the triangular wear element 12 has a width at the radially outer end 16, which corresponds to the total width of the mixing blade 6, and tapers therefrom inwardly towards a triangular point, in this case at about 40% of the total length of Blender wing 6 (measured from its radially inner end) ends.

This distribution of wear material with a mass of the material in the area of the tip and less and less wear material radially inward parts corresponds largely to the actual wear behavior in use, so that it can be assumed that after a certain time, when an exchange of the wear element 13 is due, this has over its entire length in relation to the different amount of wear material at different radial positions based even wear.

FIG. 5 shows an embodiment in which the wear element 12, which is rectangular in plan view, has an oversize compared with the recess provided in the base body 15 of the mixing blade 6 for this wear element. protrudes both in the forward direction and in the radial direction over the adjacent edges and surfaces of the base portion 15. The rectangular wear element 12 could alternatively consist of several assembled rectangular or L-shaped parts.

As shown in Figure 6, a corresponding wear element 12 may also be in the vertical direction, i. in Figure 5 perpendicular to the plane of the paper, protrude beyond the adjacent surfaces of the body 15, which results in the fact that the base body 15 is still much better protected against exposure to mix and thus better protected against wear, as in one embodiment, such as For example, it has been described in connection with FIGS. 2 and 3.

In the embodiment according to FIG. 7, the recess provided for the wearing element 12 is configured as a fold, so that a board 20 has remained standing in the lower area of the mixing blade main body 15, which serves as a support surface for the wear element 12. Such an embodiment is particularly favorable when strong torques (with respect to the longitudinal axis of a mixing blade) act on the wear element or the mixing blade 6. If the wear element 12 is fastened only with bolts, as shown by way of example in FIGS. 2 and 5, then in the case of such torques, very strong forces also act on the bolt bolts. - -

zenverbindung. The board 20 according to Figure 7 absorbs such torques, without the fastening screws 14 are excessively loaded.

In order to protect the lower front edge of the board 20 or the base body 15 against wear, the wear element 12 has at its front edge a downwardly projecting projection 28 which covers the front edge of the board 20.

If desired, however, the front edge of the wear member 12 can be made as sharp or narrow as in the example of Figure 6 by the wear element 12 is slightly extended with its dimensions in the forward direction or by the bevel 13 still slightly deeper or slightly steeper becomes.

FIG. 8 shows a variant in which the detachable wearing element 12 has an L-shaped configuration in plan view and thus better support is realized by a larger overlap and a larger connecting surface between the base body 15 and the wearing element 12. At the same time, the entire radially outer edge at the end of the mixing blade with the same wear protection material is protected against wear. In a fastening 22 of the short L-leg on the front side of the base 15 of this short leg L acts simultaneously as rotation and relieves the bolts 14 when torques with respect to the longitudinal axis of the mixing blade 6 on the wear member 12 and the beveled surface 13 act ,

FIG. 9 shows a preferred embodiment of the invention. Here, the detachable wear element 12 at the leading edge is combined with a detachable end piece 21 designed as a separate component. The screw 22 of the tail takes place in the axial direction and is possible lows deep in the end piece 21 sunk. The counterbore 23 is closed by a suitable, removable removable filling 24. The securing of the end piece 21 against rotation (about the axis of the bore 23) takes place here by overlapping 25 with the main body 15 of the mixing blade 6. The releasable wear element 12 at the leading edge is inserted between the base body and end piece 21.

A particularly preferred embodiment of the invention shows the isometric sectional view in Figure 10. The detachable wear element 12 at the leading edge covers only a part of the total length of the base body 15 and the mixing blade 6. The attachment of the detachable wear element 12 is made from the trailing edge of several screwings 14. At the corner of the trailing edge of the base body 15 is designed as a separate component releasable end piece 26 is flush. The screw 22 of the end piece 26 takes place in the axial direction. The securing of the end piece 26 against rotation takes place in this case by supporting an edge on the detachable wearing element 12. The main body 15 of the mixing blade 6 - -

can, as far as it is not protected by the releasable wear elements 12, 26, be protected by a non-detachable wear protection 27 according to the prior art against wear.

For purposes of the original disclosure, it is to be understood that all such features as will become apparent to those skilled in the art from the present description, drawings, and claims, even though they have been specifically described only in connection with certain further features, both individually and separately any combination with other of the features or feature groups disclosed herein are combinable, unless this has been expressly excluded or technical conditions make such combinations impossible or pointless. On the comprehensive, explicit representation of all conceivable combinations of features is omitted here only for the sake of brevity and readability of the description.

Claims

- PATENT APPLICATION E

1. mixing vanes (6), consisting of a fastened to a shaft base (15) and a releasable wear element (12), characterized in that the wear element

(12) and the base (15) over at least 30% of the length of the base overlap and define in this section, different areas of the cross section of the mixing blade (6).

2. mixing blade according to claim 1, characterized in that the wear element (12) comprises at least the radially outer third, preferably at least the radially outer half of the front edge of the mixing blade (6) in the running direction.

3. Mixer blade according to one of claims 1 or 2, characterized in that the wear element (12) forms the entire tip of the mixing blade (6) and the cross section of

Top of the base (15) at least partially covers.

4. mixing blade according to one of claims 1 to 3, characterized in that the mixing blade in a plan view appears parallel to the axis of the rotor substantially at right angles, wherein the base has a rectangular recess, in which the wear element substantially matching and optionally with supernatant in radial, in the axial and in the circumferential direction is used.

5. mixing blade according to one of claims 1 to 4, characterized in that the cross-section of the wear element (12) is tapered over the predominant part of its length to the front edge.

6. mixing blade according to one of claims 1 to 5, characterized in that the wear element (12) over most of its length substantially has the cross section of a rectangular trapezoid.

7. mixing blade according to one of claims 1 to 6, characterized in that the wearing element is connected by bolts (14) with the base part (15) extending from the back of the base part (15) through holes in the base part (15) to extends to the threaded holes in the wear element (12). - -

8. mixing blade according to one of claims 1 to 7, characterized in that the wear element consists of several parts (12, 21, 26), in particular a leading edge portion (12) and an end portion (21, 26).

9. mixing blade according to one of claims 1 to 8, characterized in that the wear element (12) has a decreasing from the top of the mixing blade in the direction of its radially inner end cross-section.