WO2001085322A1

WO2001085322A1 - Two-shaft compulsory mixer, use of the two-shaft compulsory mixer and method for operating a two-shaft compulsory mixer

Info

Publication number: WO2001085322A1
Application number: PCT/IB2000/000578
Authority: WO
Inventors: Ulrich Andreas Ammann
Original assignee: Ammann Aufbereitung Ag
Priority date: 2000-05-05
Filing date: 2000-05-05
Publication date: 2001-11-15
Also published as: AU2000241379A1; ATE248643T1; EP1278594A1; DE50003593D1; CN1452509A; CN1199719C; EP1278594B1

Abstract

The invention relates to a two-shaft compulsory mixer (1) whose mixing tools (4) are situated on two parallel mixer shafts (3a, 3b) in such a way and whose mixer shafts (3a, 3b) are also synchronised in such a way that with each rotation of the shafts (3a, 3b), the mixing tools (4) of both mixer shafts (3a, 3b) run from bottom to top through the horizontal line between the shafts (3a, b), axially adjacent to each other, in pairs, successively. In this way, the mixing tool pairs produce essentially continuous formations (9) as they pass through the area between the mixer shafts (3a, 3b), said formations emerging in a vertical direction between the two shafts (3a, 3b) from bottom to top. This significantly reduces the mixing times for a particular mixing quality compared to known two-shaft compulsory mixers with an identical number of middle mixing planes (5a-5h).

Description

TWO-SHAFT MIXER, USE OF THE TWO-SHAFT MIXER AND METHOD FOR OPERATING A TWO-SHAFT MIXER

TECHNICAL AREA

The invention relates to a two-shaft compulsory mixer, a use of the two-shaft compulsory mixer and a method for operating a two-shaft compulsory mixer in accordance with the preambles of the independent claims.

STATE OF THE ART

Two-shaft compulsory mixers are preferably used where medium to large quantities of powdery and / or granular mixes have to be mixed together dry or with the addition of liquid additives (binders). Especially in the provision of building material mixtures, such as concrete or asphalt, two-shaft compulsory mixers are preferably used to mix the starting materials. Since the requirements for the mixing quality are relatively high in these applications, the mixing is usually carried out in so-called batch mixers, in which certain amounts of starting materials are mixed with one another until a mixture of substances having the desired mixing quality is obtained. The mixer is then emptied and is available for mixing another specific quantity of substance (batch). The starting materials can also be mixed with one another using so-called continuous mixers, which are normally built longer than batch mixers, ie generally have more central mixing levels than these. With both twin-shaft compulsory mixer types, the batch mixer and the continuous mixer, the economy depends to a large extent on the ability of the mixer to achieve the best possible homogeneous in the shortest possible time To achieve mixing of the raw materials to be mixed.

PRESENTATION OF THE INVENTION It is therefore the task of a

To provide two-shaft compulsory mixers and a method for operating a two-shaft compulsory mixer, which, compared to the prior art, achieve a given mixing quality for a certain quantity of substance in a shorter mixing time or for an increased throughput quantity with the same or a shorter mixing time.

This object is achieved by the two-shaft compulsory mixer with the characterizing features of claim 1. In one aspect of the invention is a

Provide the two-shaft compulsory mixer with two mixer shafts equipped with mixing tools and driven in opposite directions of rotation. The mixer shafts are synchronized with each other. Their axes of rotation are arranged parallel to one another in a substantially horizontal plane and the mixing tools are arranged axially one behind the other on the mixer shafts, forming several center mixing planes arranged axially one behind the other on each mixer shaft. Mixing tools which form center-mixing planes are considered here exclusively as mixing tools which do not adjoin the end faces of the mixing trough for stripping mixed material from the same or for causing a flow and reversal of the mixed material in the wall area. The mixing tools according to the definition used here are thus located axially between these tools arranged in the end wall area of the mixing trough. Consequently, the term “center mixing planes” exclusively refers to those mixing planes that lie between the planes formed by the reversing or stripping tools. The mixing tools are arranged around the axes of rotation of the mixer shafts in such a way that they radially in different directions extend. Also, the arrangement of the mixing tools on the mixer shafts is such that the mixer shafts have opposite conveying directions when rotating in the direction of rotation and that the axial running direction of the axial sequence of two adjacent center mixing planes of the same mixer shaft, the tools of which pass the horizontal between the shafts directly in succession when rotating in the direction of rotation. is rectified in both waves. In each case, the starting point to be considered is a center mixing plane which is flanked on both sides by neighboring center mixing planes and not one which is adjacent on one side to a plane of the mixer shaft and which has stripping and / or reversing tools. The axial running direction of the aforementioned

Sequence is therefore rectified in one mixer shaft with its conveying direction, while in the other mixer shaft it is opposite to the conveying direction thereof. In the further description, the two mixer shafts are also referred to as the for explanation purposes

"Co-rotating mixer shaft" or the "counter-rotating mixer shaft" referred to. The arrangement of the mixing tools on the shafts and the synchronization of the shafts with respect to one another is also designed in such a way that at regular intervals, mixing tools of both mixer shafts pass through the horizontal between the mixer shafts, essentially axially and / or radially adjacent to one another, from bottom to top.

Due to the design of the two-shaft compulsory mixer described above, at least two of the mixing tools of both mixer shafts, i.e. at least one tool from each shaft, regularly form an essentially coherent structure as they pass through the area between the mixer shafts, which form in the vertical direction between the two shafts from below passes upwards and has a projected area in the direction of movement, which is essentially the The sum of the surfaces of the adjacent mixing tools projected in the direction of rotation corresponds. It has been shown that, compared to the two-shaft compulsory mixers known from the prior art, with an identical number of center mixing levels, this leads to a significant reduction in the mixing times for a specific mixing quality.

In a preferred embodiment of the mixer, all the mixing tools of a mixer shaft have the same radial extension from the axis of rotation of the mixer shaft, i.e. that circles of the same size are described by the outer edges of the mixing tools when the mixer shaft rotates about its axis of rotation in all center mixing planes of this shaft. The mixing tools of both mixer shafts preferably have identical radial extensions around the axes of rotation of the mixer shafts. This has the advantage that the two-shaft compulsory mixer has a symmetrical structure, which is conducive to uniform mixing, and that only a few different components are required to produce the mixer shafts.

In a further preferred embodiment, the mixer shafts are driven at an identical speed, which is particularly the case with mixer shafts in which

Mixing tools with the same radial extents adjacent to each other pass through the horizontal between the shafts, which has the advantage that the outer edges of the mixing tools have the same speeds on a circular path around the axes of rotation of the shafts.

In another preferred embodiment, the mixer shafts are driven at an uneven speed, which is advantageous, for example, if the mixing tools which pass through the horizontal between the mixer shafts adjacent to one another have different radial extents or if the number of axes on their center mixing planes ordered mixing tools unequal, the distribution of which is uniform over the circumference of the shaft if there is more than one mixing tool per center mixing plane. For example, if one of the mixer shafts per center mixing level has two mixing tools that are rotated by 180 ° around the axis of rotation of the shaft and the other mixer shaft per center mixing level has only one mixing tool, it may make sense to rotate the shaft with one mixing tool per center mixing level at twice the speed to drive the other mixer shaft and to synchronize the shafts in such a way that the two mixing tools arranged on the double arm pass through the horizontal between the mixer shafts, alternately adjacent to the mixing tool of the single arm. Advantageously, both mixer shafts of the two-shaft compulsory mixer have the same number of center mixing levels, it being preferred that these center mixing levels are arranged at the same axial positions, which means that the radial lines running through the center of the axial extent of the mixing tools are essentially congruent. Furthermore, it is preferred that the mixing tools of each mixer shaft have the same axial extent. If the distance between the axes of rotation of the mixer shafts is smaller than the sum of the greatest radial extents of the mixing tools of the two mixer shafts arranged on two center mixing planes with the same axial position and / or on two center mixing planes with adjacent axial positions, there is an overlap of the circles between the mixer shafts described by the tools when the mixer shafts rotate about their axis of rotation, which leads to an intensification of the mixing in the area between the mixer shafts. If there is an overlap of the maximum radial extents of the mixing tools arranged on center mixing planes with an axially adjacent position, then these can Mixing tools pass through the horizontal axially adjacent to each other, provided that there is no additional axial overlap between the mixing tools. The overlap ratio, ie the quotient of the rotational axis distance and the sum of the greatest radial extents of the mixing tools of both mixer shafts arranged on two center mixing planes with the same axial position and / or on two center mixing planes, is preferably in the range between 0.7 and 0.9. This results in an intensive mixing zone of advantageous width between the mixer shafts. If there is no overlap between the mixing tools arranged on the center mixing planes of the same axial position, these mixing tools can pass radially adjacent to one another through the horizontal between the shafts.

Depending on the design of the mixing tools, their arrangement on the mixer shafts and the synchronization of the mixer shafts, two-shaft compulsory mixers are also conceivable in which some mixing tools pass axially and others radially adjacent to one another through the horizontal between the mixer shafts. Are e.g. If different numbers of mixing tools with different radial extensions are arranged on center mixing planes of the mixer shafts with the same axial position, it is also conceivable that in the same center mixing planes, mixing tools alternately pass through the horizontal between the mixer shafts, once axially and once radially adjacent to other mixing tools.

In a preferred embodiment, each mixer shaft of the two-shaft compulsory mixer has exactly one mixing tool on each of its center mixing levels, i.e. both mixer shafts are exclusively equipped with single-arm mixing tools.

In another preferred embodiment has at least one mixer shaft on at least one center mixing level, at least two mixing tools, advantageously at least two on each of their center mixing levels. It is also preferred if both mixer shafts have exactly two mixing tools on each of their center mixing levels. In these cases, the at least two mixing tools arranged on a center mixing plane of a mixer shaft are advantageously arranged uniformly around the axes of rotation of the mixer shafts, for example in the case of double-arm mixing tools with an angular division based on the angle of rotation of the mixer shaft of 180 °. In this way, for example, mixers are provided with a mixing shaft equipped with 180 ° double-arm mixing tools and a mixer shaft equipped with single-arm mixing tools or mixers with two mixer shafts equipped with 180 ° double-arm mixing tools.

In a further preferred embodiment, the mixing tools are arranged on a mixer shaft in such a way that the angles of rotation which the mixer shaft in the intended operating direction of rotation between the passage through the horizontal between the mixer shafts of two mixing tools of this mixer shaft, which in the intended operating direction of rotation directly follow the horizontal pass between the mixer shafts and are located on axially adjacent center mixing planes of the mixer shaft, swept over, are of the same size. The mixing tools are thus arranged axially on the shaft and radially on the circumference of the shaft such that, when the same is rotated, the mixing tools of axially successive center mixing planes pass through the horizontal between the shafts directly in succession, and thereby the angle which, when rotated about their axis of rotation in the direction of operation is swept between two mixing tools, is the same size between all mixing tools. Here, too, a center mixing plane is to be considered as the starting point, that on both sides of neighboring ones o Φ o Φ po, d

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Operating direction of rotation between the passage through the horizontal between the mixer shafts of said first mixing tool and a next mixing tool of this first mixer shaft, which is located on an axially adjacent center mixing plane and directly follows said first mixing tool when rotated in the operating direction of rotation. As a result, axially adjacent pairs of mixing tools of both mixer shafts are formed in the area of the horizontal between the mixer shafts as they pass through the horizontal.

Said first mixer shaft is preferably the mixer shaft, the conveying direction of which when rotated in the operating direction of rotation is opposite to the axial running direction of the axial sequence of two adjacent center mixing planes of this mixer shaft, the tools of which pass through the horizontal between the shafts directly in succession when rotated in the operating rotational direction, that is to say the “opposing mixer shaft” Since the surfaces of the mixing tools pointing in the direction of rotation have to be set to form a conveying direction of the respective mixer shaft with respect to the axis of rotation of the respective mixer shaft, the mixing tools adjoining one another when passing through the horizontal in this embodiment each form a V-shaped structure in the area between the mixer shafts with the axial extension of these two mixing tools, which is moved upwards between the mixer shafts, whereas the said first mixer shaft is the mixer shaft , whose conveying direction when the mixer shaft rotates in the operating direction of rotation is the same as the axial running direction of the axial sequence of two adjacent center mixing planes of this mixer shaft, the tools of which, when rotating in the operating direction of rotation, pass the horizontal between the shafts directly in succession, that is to say the "synchronous mixer shaft", so When passing through the horizontal, the mixing tools adjoining one another in the area between the mixer shafts each form a pointed roof-shaped structure with the axial extension of two mixing tools, which is moved upward between the mixer shafts.

Since the fluidic properties of these two types of structure are very different in the direction of movement (the V-shaped structure "shovels" with its entire surface projected in the direction of movement exclusively upwards, while the pointed roof-shaped structure divides the material when moving upwards and displaces it axially in opposite directions) Depending on the material to be mixed and / or the speed of the mixing tools, one or the other version is preferred. With these versions, it is also advantageous if both mixer shafts have mixing tools with uniform radial extensions, both mixer shafts have an identical number of mixing tools, preferably single-arm mixing tools, per center mixing level the shafts are driven at the same speed, creating a uniform transfer logic across the entire mixing zone between the shafts.

If the two-shaft compulsory mixer has areas in which there is no overlap between the mixing tools arranged on the center mixing planes of the same axial position nor between the mixing tools arranged on axially adjacent center mixing planes, then the mixing tools of both shafts arranged on the center mixing planes of the same axial position pass through them

Areas of the horizontal between the waves are advantageous at the same time.

In a further preferred embodiment, each of the mixer shafts of the two-shaft compulsory mixer has at least 3 center mixing levels, in particular at least 4 center mixing levels and in particular at least 8 center mixing levels. In another preferred embodiment, the two-shaft compulsory mixer is designed as a batch mixer or as a continuous mixer.

According to claim 20, the two-shaft compulsory mixer described above is used for mixing powdery, granular or plastic materials, in particular for mixing concrete and in particular for mixing asphalt. This can be done with and without the addition of liquid substances (binders). The invention is further based on the object of providing an operating method for a two-shaft compulsory mixer in which, compared to the prior art, a given mixing quality is achieved for a certain amount of substance in a shorter mixing time or for an increased throughput amount with the same or a shorter mixing time.

This object is achieved by the method for operating a two-shaft compulsory mixer with the characterizing features of claim 21. Accordingly, a two-shaft compulsory mixer, which has a synchronous and an opposing mixer shaft, which is equipped with mixing tools, driven in opposite directions, synchronized with one another and arranged with their axes of rotation in a substantially horizontal plane parallel to one another, is operated in such a way that moderate intervals, the mixing tools of the two mixer shafts pass through the horizontal between the mixer shafts, essentially axially and / or radially adjacent to one another, from bottom to top. The mixing tools of the _^

Mixer shafts are arranged axially one behind the other, forming several center mixing planes for each mixer shaft, and arranged at several circumferential positions around the axes of rotation of the mixer shafts in such a way that the mixer shafts have opposite conveying directions when rotated in the direction of rotation and that the axial running direction of the axial sequence of two adjacent center mixing planes the same mixer shaft, the tools of which, when rotating in the direction of rotation, pass the horizontal between the shafts directly in succession, are rectified in both shafts. A two-shaft compulsory mixer, which has a single-arm mixing tool on each center mixing plane of each mixer shaft, is preferably operated in the manner described above.

In a preferred method for operating a two-shaft compulsory mixer, the mixer shafts are driven at identical speeds.

In another preferred method, these are driven at different speeds, it being preferred that one mixer shaft is driven at twice the speed of the other mixer shaft.

In a further preferred method for operating a two-shaft compulsory mixer with mixer shafts which have a shaft core designed as a polygonal shaft, the synchronization between the mixer shafts is set in such a way that the angles of rotation which a mixer shaft in the intended operating direction of rotation between the passage through the horizontal between the Mixer shafts from each of two mixing tools of this mixer shaft, which pass through the horizontal between the mixer shafts in succession in the intended direction of rotation and are located on adjacent center mixing planes of the mixer shaft, sweep the angle between two adjoining surfaces of the polygonal shaft or correspond to one another or an integral multiple, an integer Fraction or a sum of integral fractions of the angle between two adjacent surfaces of the polygonal wave to each other.

In yet another preferred method for the operation of a two-shaft compulsory mixer with mixer shafts that have an identical number of center mixing levels at the same axial positions, the synchronization between the mixer shafts is set so that the angle of rotation which a first mixer shaft in the intended direction of rotation rotates between passing through the horizontal between the mixer shafts of a first of their mixing tools and a mixing tool of the second mixer shafts arranged in the center mixing plane with the same axial position is the same as the angle of rotation which this first mixer shaft in the intended direction of rotation between passing through the horizontal between the mixer shafts of said first mixing tool and a next mixing tool of this first mixer shaft, which is located on an adjacent center mixing plane and directly follows said first tool when rotated in the operating direction of rotation, berstreicht. It is particularly preferred if, in the method described above, the synchronization of the mixer shafts is set such that the first mixer shaft is the mixer shaft, the conveying direction of which, when the mixer shaft rotates in the direction of operation, is opposite to the axial running direction of the axial sequence of two adjacent center mixing planes of this mixer shaft. whose tools, when rotating in the direction of rotation, pass the horizontal between the shafts in direct succession, that is, the "counter-rotating mixer shaft".

Alternatively, it is preferred to set the synchronization of the mixer shafts in such a way that the first mixer shaft is the mixer shaft, the conveying direction of which, when the mixer shaft rotates in the operating direction of rotation, is the same as the axial running direction of the axial sequence of two adjacent center mixing planes of this mixer shaft, the tools of which when rotating in the operating direction. Direction of rotation pass through the horizontal between the shafts in direct succession, ie the "synchronous mixer shaft".

In a further preferred method for operating a two-shaft compulsory mixer with mixer shafts, in which the radial dimensions of the mixing tools in each center mixing plane of a mixer shaft are essentially the same, the speed of the mixer shafts is set such that a Froude number in the range of 0.5 to 1.0 or in the range from 1.0 to 2.0, in particular in the range from 0.6 to 0.9, preferably for concrete, and in particular in the range from 1.1 to 1.6, preferably for asphalt.

BRIEF DESCRIPTION OF THE DRAWINGS

Further refinements, advantages and applications of the invention result from the dependent claims and from the following description based on the figures. Show:

Figure 1 is a plan view obliquely from above of a two-shaft compulsory mixer.

FIG. 2 is a side view in the axial direction of the two-shaft compulsory mixer from FIG. 1; and Fig. 3 is a top plan view of the

Two-shaft compulsory mixer from FIG. 1.

WAY (S) OF CARRYING OUT THE INVENTION

In Fig. 1, a preferred embodiment of the two-shaft compulsory mixer 1 with 8 center mixing planes 5a-5h is shown partially in section, viewed obliquely from above. The mixer is designed as a batch mixer for concrete and asphalt. As can be seen, two mixer shafts 3a, 3b are arranged in a horizontal plane parallel to one another in the mixing trough 2. The mixer shafts 3a, 3b are equipped with one-armed mixing tools 4, which axially one behind the other on the shafts 3a, 3b are arranged and form several axial center mixing planes 5a-5h for each mixer shaft 3a, 3b. The mixing tools 4 extend radially in different directions around the axes of rotation of the mixer shafts 3a, 3b and in this case consist of mixer arms with mixer blades arranged on their side facing away from the shaft axis of rotation. As already mentioned, the tools 6 adjoining the end faces of the mixing trough and arranged on the shafts essentially serve to scrape off the mixed material from the end sides of the mixing trough and, if necessary, to reverse the flow of the mixed material flow in the wall area and are not considered as mixing tools in the analysis presented here 4 viewed and do not form any center mixing levels 5a-5h according to the definition used here.

As can be seen from FIG. 1 together with FIG. 2, which is a side view in the axial direction of the mixer shafts 3a, 3b arranged in the mixing trough 2, the mixing tools 4 are arranged on the circumference of the mixer shafts 3a, 3b such that the angles of rotation, which each mixer shaft in the intended operating direction of rotation Dl, D2 between the passage through the horizontal between the mixer shafts 3a, 3b of two of their mixing tools, which in the intended operating direction of rotation Dl, D2 pass the horizontal between the mixer shafts 3a, 3b in succession and on each other adjacent center mixing planes 5a-5h of the mixer shaft are located, swept, are the same size from center mixing plane 5a-5h to center mixing plane 5a-5h and are also the same size in both mixer shafts 3a, 3b. In the case shown, the angle of rotation α is 135 ° and is thus identical to the angle formed by two adjacent surfaces of the octagonal shafts forming the mixer shaft cores. As can also be seen in FIG. 1, the mixing tools 4 are arranged on the mixer shafts 3a, 3b in such a way that the mixer shafts rotate when they are provided Operational directions of rotation Dl, D2 have opposite directions XI, X2. As can also be seen on closer inspection, in the mixer shaft 3b shown on the right, the direction of travel Y2 of the axial sequence of two adjacent center mixing planes 5a-5h of this mixer shaft 3b, the tools 4 of which, when rotating in the direction of rotation D2, the horizontal between the shafts 3a, 3b pass through, in the same direction as the conveying direction X2 of this mixer shaft 3b, that is to say that this shaft is a “synchronous one

For clarification in FIG. 1, consider, for example, the mixing tool 4 of the mixer shaft 3b arranged on the center mixing plane 5e, which in the drawing shown shows the horizontal between the mixer shafts 3a, 3b already as a result of the rotation of the mixer shaft 3b

The shaft 3b has passed in the direction of rotation D2, the adjacent center mixing plane, the mixing tool 4 of which, when rotating in the direction of rotation D2 directly following the tool 4 of the center mixing plane 5e, passes through the horizontal between the shafts 3a, 3b, is the center mixing plane 5d.

Center mixing plane 5d thus follows on center mixing plane 5e, as a result of which the axial running direction Y2 is fixed. When considering the determination of the axial running direction Yl, Y2, the axial sequence of two adjacent center mixing planes 5a-5h of the same mixer shaft 3a, 3b, the tools 4 of which pass through the horizontal between the shafts 3a, 3b directly in succession when rotating in the operating direction of rotation Dl, D2, It should be noted that the center mixing plane, which is the starting point, must be flanked on both sides by neighboring center mixing planes in order to enable the direction of travel Y1, Y2 to be determined on the basis of the sequence of the center mixing planes 5a-5h. In the case shown, only the center mixing planes 5b to 5g come as

Starting point of this consideration in question. Assumes a center mixing level that is adjacent to one If the plane of the shaft equipped with a reversing and / or stripping tool is arranged, i.e. in this case of center mixing plane 5a or 5h, then there is only a single adjacent center mixing plane 5a-5h on the other side of this center mixing plane, which is why a determination of the direction of travel Y1, Y2 is not possible based on these center mixing levels.

In the mixer shaft 3a shown on the left, however, this running direction Y1 is the same as that of the mixer shaft 3b and thus opposite to the conveying direction XI of the mixer shaft 3a, which is why it is an "opposing mixer shaft".

As can be seen from FIG. 3, the mixer shafts 3a, 3b are provided on one side with drives 7a, 7b which operate them in the intended manner

Drive direction of rotation Dl, D2 and are mechanically coupled to one another via a shaft with a positive coupling 8. The coupling means that the mixer shafts 3a, 3b are synchronized, i.e. they have a fixed angle of rotation relative to one another, and in the case shown are driven at the same speed during operation. The mixer shafts can alternatively also be coupled by means of electrical or electronic coupling of separate drives. As can also be seen from this illustration, both mixer shafts 3a, 3b have the same number of mixing tools 4 and the same number of center mixing planes 5a-5h in the same axial positions. The mixing tools 4 of both mixer shafts 3a, 3b have the same axial extents A and have no axial overlap. Their radial extension B from the axes of rotation of the shafts 3a, 3b is also the same, which is why the diameters of the circles which describe them when the mixer shafts rotate about their axes of rotation are the same in all center mixing planes 5a-5h for both mixer shafts 3a, 3b.

Since the distance C between the axes of rotation of the mixer shafts 3a, 3b is smaller than the sum of the largest radial extents B of the mixing tools 4 of both mixer shafts 3a, 3b arranged on two center mixing planes 5a-5h with the same axial position (the ratio is 0.85 in the example shown), there is an overlap of those of the mixer shafts 3a, 3b Outside edges of the mixing tools 4 of both shafts 3a, 3b on the center mixing planes 5a-5h in the same axial position circles. The extent of this overlap in the horizontal between the mixer shafts 3a, 3b in the example shown exceeds the radial extent of the mixer blades of the mixing tools 4, the axial boundary edges of which are perpendicular to the axes of rotation of the mixer shafts and the axial extensions of which are adjacent to one another in the direction of rotation. As a result, when passing through the horizontal between the shafts 3a, 3b, an essentially coherent structure 9 is formed from two mixer blade surfaces. If the extent corresponds to the overlap of the radial extent of the mixer blades of the mixing tools 4, then the axial boundary edges of the latter completely adjoin one another when passing through the horizontal between the mixer shafts 3a, 3b, as a result of which essentially coherent structures 9 with a width corresponding to the radial extent the mixer blades and an axial one

Extension corresponding to the axial extension of two mixer blades.

As can be seen in FIG. 1, the two mixer shafts 3a, 3b are synchronized with one another in such a way that with each revolution of the mixer shafts 3a, 3b, their mixer blades in pairs of two each on axially adjacent planes 5a-5h on different shafts 3a, 3b Mixing tools 4 located axially adjacent to each other pass through the horizontal between the mixer shafts 3a, 3b. In the case shown, this is achieved by the synchronization between the mixer shafts 3a, 3b it is set that the angle of rotation β (shown in FIG. 2 in the center mixing plane 5b) which the mixer shaft 3b in the intended direction of rotation D2 between passing through the horizontal between the mixer shafts 3a, 3b of a first one of them

Mixing tools 4 and a mixing tool 4 arranged in a center mixing plane 5a-5h with the same axial position sweeps over the mixer shaft 3a, is the same size as the angle of rotation α, which they rotate in the intended direction of rotation D2 between the

Passing through the horizontal of said first mixing tool 4 and a next one of their mixing tools 4, which is located on an adjacent center mixing plane 5a-5h and directly follows said first when rotating in the direction of rotation. In the embodiment shown in this example, the synchronization of the mixer shafts 3a, 3b is selected such that the mixing tools 4 of the mixer shaft 3b, in which the conveying direction X2 is the same as the running direction Y2, that is to say the “synchronous mixer shaft”, in the center mixing planes 5a-5h pass through the horizontal between the mixer shafts 3a, 3b with the same axial position by the previously described angle of rotation β earlier than the mixing tools 4 of the “counter-rotating mixer shaft” 3a. This will form the passage through the

Horizontal pairs of mixer blades that arise in the area between the mixer shafts each have a pointed roof-shaped, essentially coherent structure 9 with the axial extension of two mixer blades, which is moved upward between the mixer shafts 3a, 3b.

If the synchronization is selected such that the mixing tools 4 of the mixer shaft 3a, in which the conveying direction XI is opposite to the direction of travel Yl, that is to say the “opposite mixer shaft”, in horizontal mixing planes 5a-5h with the same axial position, the horizontal between the mixer shafts 3a, 3b run through the previously described angle of rotation ß earlier than the mixing tools 4 of the "synchronous mixer shaft" 3b (this situation is not shown in the figures), V-shaped structures 9 are formed with the axial extension of two mixer blades as the horizontal traverses.

While preferred embodiments of the invention are described in the present application, it should be clearly pointed out that the invention is not restricted to these and can also be carried out in other ways within the scope of the following claims.

Claims

1. Two-shaft compulsory mixer (1) equipped with two mixing tools (4), driven in opposite directions of rotation (D1, D2), synchronized with one another and with their axes of rotation arranged in a substantially horizontal plane, mutually parallel mixer shafts (3a, 3b) and their mixing tools (4) axially one behind the other, forming several center mixing planes (5a-5h) for each mixer shaft (3a, 3b) and extending radially in different directions around the axes of rotation of the mixer shafts (3a, 3b), such that the mixer shafts (3a , 3b) when rotating in the direction of rotation (Dl, D2) have opposite conveying directions (XI, X2) and that the axial running direction (Yl, Y2) of the axial sequence of two adjacent center mixing planes (5a-5h) of the same mixer shaft (3a, 3b), the Tools (4) pass through the horizontal between the mixer shafts (3a, 3b) in direct succession when rotating in the direction of rotation (Dl, D2); do the same for both shafts (3a, 3b) ch is directed, and the arrangement of the mixing tools (4) on the shafts (3a, 3b) and the synchronization of the shafts (3a, 3b) to one another is such that at regular intervals mixing tools (4) of both mixer shafts (3a, 3b ) pass through the horizontal between the mixer shafts (3a, 3b) essentially axially and / or radially adjacent to each other from bottom to top.

2. Two-shaft compulsory mixer (1) according to claim

1, the diameters of the circles which are described by the outer edges of the mixing tools (4) when the mixer shafts (3a, 3b) rotate about their axis of rotation, in each center mixing plane (5a-5h) of a mixer shaft (3a, 3b) essentially the same are large and in particular, these diameters being essentially the same size for both mixer shafts (3a, 3b).

3. Two-shaft compulsory mixer (1) according to one of the preceding claims, wherein the two-shaft compulsory mixer (1) has drive means (7a, 7b) for driving the mixer shafts (3a, 3b) at an identical speed.

4. Two-shaft compulsory mixer (1) according to one of claims 1 to 2, wherein the two-shaft compulsory mixer (1) has drive means (7a, 7b) for driving the

Mixer shafts (3a, 3b) with an unequal speed, and in particular, the two-shaft compulsory mixer (1)

Drive means (7a, 7b) has for driving a first mixer shaft (3a, 3b) at twice the speed of the second mixer shaft (3a, 3b).

5. Two-shaft compulsory mixer (1) according to one of the preceding claims, wherein both mixer shafts

(3a, 3b) have the same number of center mixing planes (5a-5h) and in particular, the center mixing planes

(5a-5h) are arranged in the same axial positions, and in particular, the mixing tools (4) of each mixer shaft (3a, 3b) having the same axial extensions (A).

6. Two-shaft compulsory mixer (1) according to one of the preceding claims, wherein the distance (C) of the axes of rotation of the mixer shafts (3a, 3b) to one another is smaller than the sum of the respective greatest radial extensions (B) of the two center mixing planes (5a- 5h) with the same axial position and / or with mixing tools (4) of both mixer shafts (3a, 3b) arranged on two center mixing planes (5a-5h) with adjoining axial positions, and in particular, the quotient of the axis of rotation distance (C) and the sum of said greatest radial extents (B) is in the range between 0.7 and 0.9.

7. Two-shaft compulsory mixer (1) according to one of the preceding claims, wherein each mixer shaft (3a, 3b) has exactly one mixing tool (4) on each of its center mixing planes (5a-5h).

8. Two-shaft compulsory mixer (1) according to one of claims 1 to 6, wherein at least one mixer shaft (3a, 3b) has at least two mixing tools (4) on at least one center mixing plane (5a-5h), and in particular, at least one the mixer shafts (3a, 3b) has at least two mixing tools (4) on each of their center mixing levels (5a-5h), and in particular, wherein both mixer shafts (3a, 3b) have two mixing tools (4) on each of their center mixing levels (5a-5h) ,

9. Two-shaft compulsory mixer (1) according to claim

8, the at least two mixing tools (4) arranged on a center mixing plane (5a-5h) of a mixer shaft (3a, 3b) being arranged uniformly at circumferential positions around the axes of rotation of the mixer shafts (3a, 3b).

10. Two-shaft compulsory mixer (1) according to one of the preceding claims, wherein the angle of rotation (α) which a mixer shaft (3a, 3b) in the intended direction of rotation (Dl, D2) between the passage through the horizontal between the mixer shafts (3a, 3b) each of two mixing tools (4) of this mixer shaft, which pass through the horizontal between the mixer shafts (3a, 3b) in direct succession in the intended direction of rotation (Dl, D2) and which are located on adjacent center mixing planes (5a-5h) of the same mixer shaft ( 3a, 3b) are located, swept over, are of the same size and in particular, these angles () being the same in both mixer shafts (3a, 3b).

11. Two-shaft compulsory mixer (1) according to claim 10, wherein the angles of rotation (α) are 135 ° or 120 ° or 90 ° or 60 ° or 45 °.

12. Two-shaft compulsory mixer (1) according to claim 6 and according to one of claims 7 to 11, wherein the angle of rotation (β), which a first mixer shaft (3a, 3b) in the intended direction of rotation (Dl, D2) between passing through the Horizontal between the mixer shafts (3a, 3b) of a first one of them Mixing tools (4) and a mixing tool (4) of the second mixer shaft (3a, 3b) arranged in a center mixing plane (5a-5h) with the same axial position, is the same size as the angle of rotation (α) which this first mixer shaft (3a , 3b) in the intended direction of rotation (Dl, D2) between the passage through the horizontal between the mixer shafts (3a, 3b) of said first mixing tool (4) and a next mixing tool (4) of this first mixer shaft (3a, 3b), which is located on an adjacent center mixing plane (5a-5h) and directly follows said first when rotated in the direction of rotation.

13. Two-shaft compulsory mixer (1) according to claim 12, wherein the first mixer shaft (3a, 3b) is the mixer shaft (3a), the conveying direction (XI) of which when the mixer shaft (3a) rotates in the operating direction of rotation (DI) is opposite to the axial running direction (Yl) the axial sequence of two adjacent center mixing planes (5a-5h) of this mixer shaft (3a), the tools (4) of which pass through the horizontal between the shafts (3a, 3b) in direct succession when rotating in the direction of rotation (Dl).

14. Two-shaft compulsory mixer (1) according to claim 12, wherein the first mixer shaft (3a, 3b) is the mixer shaft (3b), the conveying direction (X2) of which when the mixer shaft (3b) rotates in the direction of rotation (D2) is the same direction as the axial running direction (Y2) the axial sequence of two adjacent center mixing planes (5a-5h) of this mixer shaft (3b), the tools (4) of which pass through the horizontal between the shafts (3a, 3b) in direct succession when rotating in the direction of rotation (D2).

15. Two-shaft compulsory mixer (1) according to one of the preceding claims, wherein at least one

Mixer shaft (3a, 3b) comprises a shaft core designed as a polygonal shaft, on which the mixer witness (4) are attached, and in particular, which is designed as a square shaft, hexagonal shaft or octagonal shaft.

16. Two-shaft compulsory mixer (1) according to claim 15, wherein the angle of rotation (α) which the

Mixer shaft (3a, 3b) in the intended direction of rotation (Dl, D2) between the passage through the horizontal between the mixer shafts (3a, 3b) of each two mixing tools (4) of this mixer shaft (3a, 3b), which in the intended direction of rotation ( Dl, D2) pass through the horizontal between the mixer shafts (3a, 3b) in direct succession and are located on adjacent center mixing planes (5a-5h) of the mixer shaft (3a, 3b), swept over, correspond to the angle between two adjacent surfaces of the polygonal shaft or one correspond to integer multiples, an integer fraction or a sum of integer fractions of the angle between two adjacent surfaces of the polygonal shaft.

17. Two-shaft compulsory mixer (1) according to one of the preceding claims, wherein each of the mixer shafts (3a, 3b) at least 3 center mixing levels (5a-5c), in particular at least 4 center mixing levels (5a-5d) and in particular at least 8 center mixing levels (5a-5h ) having.

18. Two-shaft compulsory mixer (1) according to one of the preceding claims, wherein the mixer shafts (3a, 3b) are mechanically rotationally coupled or wherein the mixer shafts (3a, 3b) are electrically or electronically rotationally coupled.

19. Two-shaft compulsory mixer (1) according to one of the preceding claims, wherein the mixer (1) is a batch mixer or wherein the mixer (1) is a continuous mixer.

20. Use of the two-shaft compulsory mixer

(1) according to one of the preceding claims for mixing powdery, granular or plastic mixed materials, in particular for mixing concrete and in particular for mixing asphalt.

21. A method of operating a two-shaft compulsory mixer (1) which has two mixer shafts (3a.) Equipped with mixing tools (4), driven in opposite directions (Dl, D2), synchronized with one another and with their axes of rotation in a substantially horizontal plane , 3b), the mixing tools (4) of which are arranged axially one behind the other, forming several center mixing planes (5a-5h) for each mixer shaft (3a, 3b) and extending radially in different directions around the axes of rotation of the mixer shafts (3a, 3b), such that the mixer shafts (3a, 3b) have opposite conveying directions (XI, X2) when rotating in the operating direction of rotation (Dl, D2) and that the axial running direction (Yl, Y2) of the axial sequence of two adjacent center mixing planes (5a-5h) of the same mixer shaft (3a, 3b), whose tools (4) pass through the horizontal between the mixer shafts (3a, 3b) in direct succession when rotating in the direction of rotation (Dl, D2) The two shafts (3a, 3b) are aligned in the same direction, and the synchronization of the shafts (3a, 3b) to one another is set in such a way that mixing tools (4) of both mixer shafts (3a, 3b) go from bottom to top at regular intervals pass through the horizontal between the mixer shafts (3a, 3b) essentially axially and / or radially adjacent to one another.

22. The method for operating a two-shaft compulsory mixer (1) according to claim 21, wherein each mixer shaft (3a, 3b) of the two-shaft compulsory mixer (1) is equipped with exactly one mixing tool (4) on each center mixing plane (5a-5h).

23. A method for operating a two-shaft compulsory mixer (1) according to one of claims 21 to 22, wherein the mixer shafts (3a, 3b) are driven at identical speeds.

24. Method for operating a two-shaft A compulsory mixer (1) according to any one of claims 21 to 22, wherein the mixer shafts (3a, 3b) are driven at different speeds, and in particular, wherein one mixer shaft (3a, 3b) is driven at twice the speed of the other mixer shaft (3a, 3b) becomes.

25. A method of operating a two-shaft compulsory mixer (1) according to one of claims 21 to 24, wherein with mixer shafts (3a, 3b) have a shaft core designed as a polygonal shaft and the angle of rotation (α), which a mixer shaft (3a, 3b) in the intended direction of rotation (Dl, D2) between the passage through the horizontal between the mixer shafts (3a, 3b) of two mixing tools (4) each of these mixer shafts (3a, 3b), which in the intended direction of rotation (Dl, D2) directly successively traverse the horizontal between the mixer shafts (3a, 3b) and are located on adjacent center mixing planes (5a-5h) of the same mixer shaft (3a, 3b), sweeping over them, corresponding to the angle between two adjacent surfaces of the polygonal shaft or an integral multiple, an integer Corresponding to a fraction or a sum of integral fractions of the angle between two adjacent surfaces of the polygonal shaft s.

26. Method for operating a ^' two-shaft

A compulsory mixer (1) according to one of claims 21, 22 or 25 and according to claim 23 with mixer shafts (3a, 3b) which have an identical number of center mixing planes (5a-5h) which are arranged in the same axial positions, the synchronization between the Mixer shafts (3a, 3b) is set so that the angle of rotation (β), which a first mixer shaft (3a, 3b) in the intended direction of rotation (Dl, D2) between passing through the horizontal between the mixer shafts (3a, 3b) one first of their mixing tools (4) and a mixing tool (4) arranged in a center mixing plane (5a-5h) with the same axial position

are the same size, the speed of the mixer shafts (3a, 3b) being set such that a Froude number in the range from 0.5 to 1.0 or in the range from 1.0 to 2.0 results, in particular in the range from 0.6 to 0.9, and in particular in the Range from 1.1 to 1.6 results.