EP2119496B1 - Mixing device and tool - Google Patents

Abstract

The mixing tool (2) comprises a mixing coil (4) and an arm (3) with two ends. A mixing tool drive is provided for driving the mixing coil. A connecting element is provided for connecting the mixing tool with a mixing device on one end of the arm. The connecting element is formed as a flange (11), where the position of the mixing coil is adjusted in the mixing device.

Description

Field of the invention

The invention relates to a mixing tool for installation in a plate mixing device for mixing concrete quantities or other mixtures of several components. The mixing tool comprises at least one arm with two ends, wherein at one end of the at least one arm, a rotating mixing helix is mounted with a mixing helix rotation axis. The invention also relates to a mixing device for mixing a mixture of several components with such a mixing tool.

State of the art

The market for concrete products and precast concrete products is characterized by a large variety of products in terms of their material composition, their geometric dimensions, the surfaces, colors and solid concrete properties. In the last two decades, concrete technology has undergone a development that requires a rethink in dealing with the material concrete. Innovations such as high-performance concretes or self-compacting concretes, which basically can only be produced since there are powerful concrete admixtures and highly effective superplasticizers, are prerequisites, for example, for the realization of modern, in particular architectural requirements. The processing of cement-bound mixtures and in particular the machine technology used in this case is of particular importance in meeting the material-technical requirements.

The process chain of the processing of cementitious mixtures for the production of concrete products ranges from the preparation and metering of raw materials through the mixing process, transport and shaping to compaction. The mixing process is of particular importance. Mixing is one of the basic operations of process engineering. This is understood to mean the material combination of different starting materials. Before the mixing process, the starting materials are separated and often present in different states of aggregation, and the composition also varies as a rule. In the mixing process, these starting materials are mixed, combined, homogenized or homogenized. The aim of each mixing process consists in a uniform distribution of all components of the starting materials in the total mixture, the so-called population. Each sample should therefore have the same composition as the population after mixing. The degree of homogenization is called mixed quality. The prerequisite for achieving a high product quality with high efficiency is therefore the creation of an evenly distributed mixing quality in the population within the shortest possible time. The assessment of the mixing quality is regulated in DIN 459-2 (11/1995).

For the production of concrete and mortar with hydraulic binders mixing device, mainly mechanical mixers are used. In accordance with DIN 459-1 (11/1995), a distinction is made between discontinuously operating batch mixers and continuously operating continuous mixers, depending on the mode of operation. Depending on the design, the discontinuous concrete mixers are subdivided into plate, trough and drum mixers. These mixer types are predominantly used in the precast concrete industry. You will be charged with a container size and type associated amount of mix. The mix is mixed for a predetermined period, then the mixing container is emptied. All Mischgutbestandteile be equally subjected over a certain period of the mixing process, the mixing time can be variably adapted to the properties of the batch.

Another type of classification of mixer types can be made by the nature of the movement of the mix, as for example in an article by P. Nolt and R. Loewe in the journal BWI - Concrete Plant International, No. 3, June 2004, pages 54-77 described. According to this classification, there are so-called compulsory mixers, which forcibly move the mix by rotating mixing tools and thereby mix thoroughly and with high mixing quality. So-called free-fall mixers on the other side have a rotating drum vessel with internal blading. By turning the drum, the mix is lifted and mixed in free fall. However, compared to compulsory mixers, free-fall mixers have a long mixing time and lower mixing quality.

A type of compulsory mixer often encountered in concrete works is the so-called plate mixer. This consists of a stationary in operation or rotating mixing container with vertical or inclined symmetry or rotation axis. Depending on the design of the plate mixer as ring trough mixers, planetary mixers, cone mixers or Eirich mixers, to name a few mixer types, the plate mixer has fixed or rotating mixing tools which are arranged centrically or eccentrically with respect to the axis of symmetry. Due to the rotational movements of the movable components, a homogenization of the mixed material is achieved, wherein the main direction of movement of the batch components runs parallel to the mixer bottom. In the mixing tools are usually mixing blades, which are arranged obliquely, so that an additional vertical movement of the mixed material takes place in order to achieve in this way over the entire volume uniformly high mixing quality. However, since these blades are arranged, for example, in a ring trough mixer or planetary mixer with drum-shaped mixing container on the bottom of the mixing container or at a fixed height, the mixing in the vertical direction is often not sufficient, the batch flows do not go through the entire batch height. On the contrary, areas occur in which the mixing is poor. In particular, when mixing water, this can lead to consistency variations within a batch of the mixture, so that ultimately quality losses are to be expected.

The mixing of fibers or the mixing of self-compacting concrete - the latter must be mixed with a high-performance fluid - requires an intensive mixing process to achieve a high mixing quality, with the movements of the mixing tools many shear planes must be generated in the mix.

In order to improve the mixing, various possibilities are proposed in the prior art, which inter alia include vertical conveying of the mixture to improve vertical mixing. So is in the DE 31 14 447 C1 a ring trough mixer described, which has for mixing the mixing material mixing tools that rotate about a vertical, eccentric axis. These mixing tools can be designed as Rührwendel, such as in the compact mixer B53-D Beba. Although turbulence is possible with such tools, the necessary material flows are not reached upwards for the highly technical mixtures used today, but turbulence rather takes place in the plane in which the stirring heads of the stirring tools move.

In order to improve the vertical material transport, is in the De 198 06 140 A1 proposed over the entire radius of a drum-shaped mixing vessel at least one, but preferably to use two superimposed snails with horizontal and radial rotational axes. These screws are used in addition to the other existing tools. In this device, above all, a thorough mixing along the entire radius of the mixing container is achieved, whereby inevitably the mixture is also moved to a small extent vertically, namely on the diameter of the horizontal screw lying.

In the DE 199 50 743 A1 a cone mixer is described, which also has several mixing tools. These are on the one hand mixing arms with mixing paddles which coat the mixing container surface touched by the mixture, and on the other hand a stirrer, which comprises a vertically arranged screw whose axis of rotation is arranged centrally with respect to the cross-sectional area of the mixing container. The axis of rotation of the agitator and that of the mixing arms are coaxial. With the centrally running worm agitator, the mix can be conveyed in the vertical direction, the mixed material conveyed by the worm also experiences a rotational movement. Thus, although a good vertical mixing of the mixture is achieved in the center of the mixing device, in the outdoor areas, the mixture is still only whisked, so that both movements are rather separated and thus the vertical transport of the mixture takes place in a region in which the mixture is not is whisked. In this way, the mixing times can not be significantly shortened to achieve a correspondingly high mixing quality.

In the DE 101 37 489 A1 a mixing device for mixing powdered or fine-grained substances with water is described. The mixing tool comprises an approximately triangular bearing seat plate, at the corners of which mixing helices are arranged at a fixed distance from a central axis of rotation. The mixing helices are driven by a mixing tool drive. The connection to a mixing device takes place via a flange. The mixing spirals transport mixture downwards.

In the US 4,034,967 a mixer is described which consists of a mixing container and two mixing spirals, wherein the elements are adapted in size and arrangement relative to each other so that no areas are formed in which unmixed components can settle. The two mixing spirals are arranged close to each other, so that on the one hand their spirals interlock and they can be driven to the other via a common gear, engage in the appropriate, attached to the mixing helices gears.

In the DE 297 22 838 U1 describes a ring trough compulsory mixer, which has a radially projecting housing, set on the mixing tools. The mixing tools are designed rod-shaped.

Description of the invention

The object of the invention is therefore to develop a mixing tool with which an improved compared to the prior art, more efficient mixing of mixture of a plurality of components, in particular concrete amount is achieved.

This object is achieved for a mixing tool of the type described above by the position of the mixing helix rotational axis in the plate mixing device with respect to a central axis of rotation is variably adjustable. The mixing spiral - also referred to as a screw - promotes mixing against gravity during rotation. The position of the mixing helix, i. The position of the mixing helix rotational axis with respect to a central axis of rotation or symmetry of the plate mixing device is adjustable with respect to the distance to this central axis of rotation.

In a preferred embodiment of the invention, the mixing tool has two arms, the arms preferably include an angle of 180 degrees. At the outer, opposite ends of the two arms, i. the ends further away from each other, the mixing helices are arranged. In this way, the mixing can be improved without driving the design effort too much in the air. The two arms can also be combined and manufactured as a structural unit, which increases the stability. The mixing tool drive, which can be arranged, for example, in the interior of the arms designed as a unit, then drives both mixing spirals. The use of several arms is possible. For example, three arms may be arranged in a star shape around the connector at an angle of 60 degrees, or four and more arms. Also asymmetric arrangements with respect to the angle and the length of the arms are feasible variants, the latter in particular to reach as far as possible areas of the batch. Also in the middle, below the connector, an additional mixing coil can be arranged.

In the variation of the distance to the central axis of rotation care must be taken that no spatial conflicts with other, in particular rotating mixing tools, which are mounted in the plate mixing device arise. Possible settings include, for example, the tangential or radial alignment of the arm, so that either a large area along a radial or a tangential direction is mixed in the vertical direction, wherein at a radial position, a larger area of the batch is mixed vertically, while at a tangential Setting and rotating about the centric axis mixing tools mixing a range on the inner circumference of the mixing vessel. Basically, all other intermediate settings possible. Overall, in this way a required mixing quality in the aggregate aggregate can be achieved in a much shorter time than in the prior art.

The central axis of rotation and the mixing helix axes of rotation are usually parallel, i. the rotating mixing helixes in a direction corresponding to the screw guide set direction of rotation counter to gravity in the vertical direction upwards. The rotational relative movement between mixing tools and mixing container may mean, on the one hand, that the mixing container rotates about fixed mixing tools, but on the other hand, that the mixing container is fixed and rotate the mixing tools in this around the central axis of rotation. Both devices are equivalent in their effect. The mixing tools themselves can also be designed so that they rotate about a common axis. By way of example, the mixing tool according to the invention can be designed such that the mixing spirals rotate about a common axis of rotation in the middle of the arm. If the mixing tool is mounted in a planetary mixer, then this additional rotation can be realized for example by an additional planetary gear, which is itself driven by the planetary gear of the mixer.

In this case, the connector is designed as a flange - with holes mounted on the circumference - whose dimensions are selected so that a connection to the arms of conventional plate mixing devices, in particular planetary mixers or planetary countercurrent mixers, can be readily produced. An exchange with attached to these arms mixing tools in commercial mixers is readily possible in this way. If necessary, a corresponding Anflanschstück must be attached as an adapter to the plate mixing device, if it is not there. In this way, the position of the mixing coil (s) in the plate mixing device can be easily changed and set as variable: The position of the arm can be easily and mechanically robustly changed by means of the flange, since the existing holes usually on a flange insertion into different positions with subsequent screwing with a corresponding Anflanschstück on a boom of the plate mixing device allow. Alternatively, the position of the arm between radial and tangential with respect to the axis of symmetry of the plate mixing Vorrichung can also be motorized, this can be provided an internal or external control device. This allows adjustment during operation.

The mixing tool in this case has a mixing tool drive, which is preferably designed as a toothed belt drive or gear drive and drives both mixing spirals. The mixing tool may be provided with its own motor, but preferably it has a coupling through which the mixing tool drive with the drive of a plate mixing device is coupled. The clutch expediently comprises a drive pinion, which is set in rotation by the drive of the mixing device and transmits this to the drive. Other, common types of coupling are usable.

If the mixing tool is provided with its own motor, the rotational speed of the mixing spirals can also be adjusted by means of a corresponding control device. Alternatively, the mixing tool on Übersetzungsseinstellmittel, with which the ratio between the drive of the plate mixing device and the mixing tool drive can be variably adjusted. This allows adaptation to different batch types. Since the drive of the plate mixing device generally only produces rotations with low rotational frequencies, a translation into faster rotations is preferably carried out.

In the plate mixing devices, in which the mixing tool can be used, either the mixing container rotates with fixed - but rotating - mixing tools around the axis of symmetry of the mixing container, or the mixing tools in the container. An opposite rotation of container and tools is possible. In order to achieve the rotational movements, the plate mixing device generally has a planetary gear, wherein the sun gear rotates about the central axis of rotation and thereby drives the mixing tools and possibly rotated. About the coupling of the mixing tool drive is coupled via the planetary gear with the drive of the plate mixing device. The drive then drives the mixing tools via the planetary gear, so that they rotate about the axis of symmetry. In this way can be dispensed with a separate motor in the first mixing tool, the drive of the mixing tool drive via the planetary gear of the mixing device. The ratio between the planetary gear and the toothed belt drive is variably adjustable, for example, the clutch may have integrated Übersetzungsseinstellmittel.

As a second mixing tool, for example, a slider or a mixing blade in question, or even a pair of such blades, which can also rotate about a common, eccentric second axis of rotation. A third mixing tool can be designed as a scraper. The use of further, known in the art mixing tools is also possible.

Brief description of the drawings

Fig.1

eine Mischvorrichtung mit verschiedenen Mischwerkzeugen,

Fig.2

die Mischwerkzeuge aus Fig.1 in einer perspektivischen Ansicht ohne die übrigen Elemente der Mischvorrichtung,

Fig.3

eine Ansicht eines Mischwerkzeugs von vorn und

Fig.4

das Mischwerkzeug aus Fig.3 in einer perspektivischen Ansicht von oben.

The invention will be explained in more detail by way of example with reference to the accompanying drawings, which also disclose features essential to the invention. Show it:

Fig.1

a mixing device with different mixing tools,

Fig.2

the mixing tools Fig.1 in a perspective view without the remaining elements of the mixing device,

Figure 3

a view of a mixing tool from the front and

Figure 4

the mixing tool Figure 3 in a perspective view from above.

Detailed description of the drawings

In Fig.1 a mixing device for mixing a mixture of several components is shown. The mixing device is based on the principle of a plate mixer and comprises a drum-shaped mixing container 1 with a circular cross-sectional area. The mixing device also comprises a first mixing tool 2, which in turn comprises two rotating mixing helices 4 with mixing helix axes of rotation attached to two arms 3. The arms 3 are here arranged at an angle of 180 degrees to each other and configured as a unit of two individual arms, but it can also be two single arms that do not form a unit used. A second mixing tool is designed as a conventional mixing star 5 with mixing blades 6. In Fig.1 is the second mixing tool, the mixing star 5 arranged behind the first mixing tool 2. The mixing blades 6 are here shown slightly above the bottom of the mixing container 1, but they can also be mounted in the vertical direction still higher or at different heights. As a third mixing tool, the mixing device also has one or more scrapers 7a, 7b, with scraper 7a mixture is scraped off the ground, with scraper 7b batch of the wall of the mixing container 1. mixing stars 5 and scrapers 7a, 7b belong to the standard equipment one mixing device. Above the mixing container 1 is a drive 8, by means of which a planetary gear 9, the mixing tools are driven, so that they rotate about a central axis of rotation R. With the help of the planetary gear 9 also the mixing star can be set directly in rotation, including a further planetary gear can be provided. In order to set the mixing spirals 4 in rotation, the first mixing tool 2 has a corresponding coupling and its own drive. About a Anflanschstück 10, the first mixing tool 2 can be connected to the planetary gear 9 of the mixing device, the orientation of the combined to form a unit two individual arms 3 with respect to the central axis of rotation R can be done arbitrarily between radial and tangential position.

In Fig.2 are the mixing tools off Fig.1 without the mixing device shown in detail in perspective view. As a counterpart to Anflanschstück 10 for the first mixing tool 2 is used at this a flange 11. Also shown is a drive pinion 12, which is basically assigned to the planetary gear 9 in the mixing device. Here, however, the drive pinion 12 is assigned to the first mixing tool 2, since a coupling, not shown, is connected to the drive pinion 12, which makes it possible to realize different gear ratios from the planetary gear 9 to the mixing tool drive. Since the rotation mediated by the planetary gear is rather slow and too low for an efficient mixing of the batch, it is preferable to choose a gear ratio to the faster, for example between 1: 2 and 1: 4. The mixing helices 4 may for example have a diameter between 300 mm and 1000 mm and an increase between 300 mm and 800 mm. However, these details are only to be understood as examples and relate to typical mixer sizes. Depending on the dimensions of the mixing container 1, deviating dimensions of the mixing coils 4 are also possible. The mixing helices 4 are also provided at their lower end with sliders 13. These allow an additional improvement of the horizontal and vertical mixing of the batch.

The first mixing tool 2 is in the FIGS. 3 and 4 shown in more detail. The assembly of two individual arms 3 is shown open to more clearly show the mixing tool drive therein, a toothed belt drive. When the housing wall of the unit is still an upper housing part 14 and a lower housing part 15 can be seen, between which the toothed belt drive is located, which is shown here only schematically by a rotating toothed belt 16 which is guided over guide rollers 17. The pulleys 17 serve as tension rollers at the same time. Inside the arm housing is behind the timing belt 16 - not shown - the clutch. The translation is usually fixed, but the device may be designed to allow for the variable adjustment of translations - controlled manually or externally. By means of the flange 11, the first mixing tool 2 can be used on the Anflanschstück 10 a mixing device, in this way, the first mixing tool 2 on the one hand easily interchangeable and on the other hand universally used in various mixing devices, if they have corresponding Anflanschstücke 10. You may also be able to use adapters to deliver a connection. Another type of connection is possible, which allows a motorized and controlled adjustment of the positions of the mixing helix rotational axes E relative to the central symmetry or rotation axis R.

With the help of the first mixing tool 2, which can be used universally, in particular in planetary mixers and planetary countercurrent mixers, can be mixed in Mixed mass produce vertical streams against gravity, so that the mixture is mixed more efficiently. The transport of the mixture in the vertical direction takes place with the aid of the mixing helices 4. The mixing is intensified compared to the usual plate mixers by the additional vertical direction of movement, resulting in an overall shorter mixing time for the same or better mixing quality.

LIST OF REFERENCE NUMBERS

1

mixing tank

2

first mixing tool

3

poor

4

mixing shaft

5

mixing star

6

mixing paddle

7a

scraper

7b

scraper

8th.

drive

9

planetary gear

10

Anflanschstück

11

flange

12

pinion

13

pusher

14

Upper housing part

15

Lower housing part

16

toothed belt

17

guide rollers

R

centric axis of rotation

e

eccentric rotation axis

Claims (10)

1. Mixing tool (2) to be installed in a ring-pan-mixer device to mix fresh concrete or other mixtures consisting of several components, comprising

   - at least one arm (3) with two ends,

   - on one end of at least one arm (3) a mixing screw (4) with a mixing screw rotational axis (E),

   - a mixing tool drive, driving the mixing screw (4) and

   - a connection linkage designed as a flange (11) to connect the mixing tool (2) with a ring-pan-mixer device,

   - characterized in that the positioning of the mixing screw rotational axis (E) in the ring-pan-mixer device regarding the distance to the centric rotational axis (R) of the ring-pan-mixer device is variably adjustable.
2. Mixing tool (2) according to claim 1, characterized in that it has two arms and the mixing tool drive is moving the mixing screws (4) together.
3. Mixing tool (2) according to claim 2 characterized in that the two arms (3) are produced as one unit and are arranged in an angle of 180 degrees to each other.
4. Mixing tool (2) according to one of the claims 1 to 3, characterized in that the mixing tool drive is designed with a tooth belt drive or a gear wheel drive.
5. Mixing tool (2) according to one of the claims 1 to 4, characterized in that it comprises a clutch for the coupling of the mixing tool drive with the drive of the ring-pan-mixer devise, so that the mixing tool drive is powered by the ring-pan-mixer-device.
6. Mixing tool (2) according to one of the claims 1 to 5, characterized in that the clutch comprising one drive pinion (12).
7. Mixing tool (2) according to one of the claims 1 to 6, characterized in that the mixing tool (2) comprising an adjusting device for the gear ratio to variably manipulate the ratio between the drive of the ring-pan-mixer device and the mixing tool drive.
8. Mixing tool (2) according to one of the claims 1 to 4, characterized in that the mixing tool drive contains an engine.
9. Ring-pan-mixer device to mix fresh concrete or other mixtures consisting of several components, comprising

   - a drum-shaped mixing bucket (1) with a circular cross section,

   - a first mixing tool (2) according to one of the claims 1 to 8, with two arms (3) designed as one unit with an attached rotating mixing screw (4) with mixing screw rotational axis(E),

   - at least a second mixing tool,

   - Resources to create a rotational relative movement between the mixing tools and the mixing bucket (1) around a centric rotational axis (R), going vertical through the center of the circular cross section,

   - whereby the mixing screw (4) conveys the mixture against the force of gravity when rotating and

   - whereby the position of the mixing screw rotational axis (E) relative to the position of the centric rotational axis (R) is adjustable concerning the distance to the centric rotational axis (R).
10. Ring-pan-mixer device according to claim 9, characterized in that the first mixing tool (2) is coupled by a clutch with the planetary gear (9) that is driven by a drive, whereby the drive is driving at least the two mixing tools via the planetary gear, so that the mixing tools are rotating around the centric rotational axis (R).

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