EP3189889A1 - Mixing device and tool for mixing - Google Patents

Abstract

The invention relates to a mixing device (1) for mixing mixed material with a container (2) rotatably mounted about a vertical axis (3) for receiving the mixture with an opening (4) and through the opening (4) into the container (2). reaching in and around a rotation axis (9) rotatable mixing tool (7) with at least one mixing coil (12) to transport the mix substantially along a container wall (15) of the container (2) upwards, wherein the axis of rotation (9) of the mixing tool (7) obliquely to the vertical axis (3) of the container (2). The container bottom (11) is cone-shaped and the mixing tool (7) carries a plurality of mixing arms (20), wherein at least one of the mixing arms (20) on the side facing away from the central shaft (13) has a freestanding end.

Description

The invention relates to a mixing device for mixing mixed material, such as dry and / or wetted solids and / or liquids, with a rotatably mounted about a vertical axis container for receiving the mix with an opening and a reaching through the opening into the container and rotatable about an axis of rotation Mixing tool with at least one mixing spiral to transport the mix substantially along a container wall of the container upwards, wherein the axis of rotation of the mixing tool is in operation obliquely to the vertical axis of the container. Furthermore, the invention relates to a mixing tool.

Such a mixer is for example in the DE 29 02 570 C2 described. The mixer has a downwardly tapered container which is closed by a rotatably mounted on the container lid. A rotatably disposed in the container screw is held off-center on the lid and extends obliquely to the central axis and parallel to the side wall of the container in the direction of the container bottom, which is formed as tapering upwards. The problem with this mixer is that, in particular in the bottom area of the container wall, material accumulations can occur and that the mix can not be effectively mixed.

From the DE 707 621 A a device for mixing powdery substances is known, comprising a container for receiving the mixed material and a mixing tool in the form of a mixing screw on a worm shaft. The container has at its lower end an outlet for the mix. By rotating the worm shaft, the mixing screw conveys the mix from the lower end to the upper end of the container. The worm shaft is hollow and provided with nozzles to introduce liquid or plastic substances under pressure into the vessel interior.

To guide the worm shaft close to the container wall, this is made in two parts, with the individual parts are coupled via a universal joint. At the bottom of the container, which is just shaped, as well as at the upper end of the worm shaft this is rotatably mounted centrally on the container in each case. At the lower end or part of the screw, this has a stirring or bluff body in the form of an L-shaped arm, which is arranged directly above the bearing of the worm shaft. The disadvantage here is that, especially in the area of storage material accumulation arises that is not mixed effectively. The two-part design of the shaft is difficult, because it makes an additional storage in the lower tank area necessary. In addition, the system is not suitable for mixing devices in which the container is provided not only as a mixing container but also as a transport container that can be removed from the mixing device. For industrial use, such a mixing device is inefficient, because with removal of the mixing container and the agitator is removed.

A similar concept describes the DE 24 25 727 C3 , The mixing device described therein comprises a mixing vessel which widens conically upwards and which rotates about its central axis and which comprises two spiral-shaped stirring members which project into the container obliquely and on opposite sides of the container wall. Centrally at the bottom of the container, a vortex device is provided, which consists of a rotatably mounted in the container bottom hub, which comprises a concentrically provided with a nozzle injection pipe and mixing arms. The container bottom extends from the side wall in the direction of the container center initially obliquely upwards and then goes over into a steeply upwardly extending point on which the hub is rotatably mounted is. The mixing arms are arranged at the upper end of the hub and thus spaced from the container bottom

The object of the present invention is to propose a mixing device which exhibits more efficient mixing properties in the bottom area of the container. Furthermore, the mixing device should have a simpler structure.

This object is solved by features of claim 1.

According to the invention it is provided that the container bottom is conical and that the mixing tool carries at a directed to the container bottom of the container end multiple mixing arms, which are fixed at one end to a central shaft of the mixing tool and which are guided by rotation of the mixing tool along the bottom, said at least one of the mixing arms has a freestanding end on the side facing away from the central shaft side.

The at least one mixing arm is free-standing at the other end opposite the one end fixed to the central shaft and e.g. not attached to the mixing spiral. It extends from the central shaft in the direction of the container wall and ends in a section which in particular does not carry the mixing helix. He is to be distinguished from a holding arm. Retaining arms are provided on the central shaft to keep the mixing coil at a distance from the central shaft. They are attached at one end to the central shaft and at the other end they carry the mixing coil.

The conical bottom is formed so that it tapers upwards or tapers towards the top and effectively directs the mixture in the direction of mixing helix or mixing arms. As a result of the inclination of the axes of rotation rotate Mixing arms diagonally to the tank axis. When the container is rotated, a mixing arm and a section of the container bottom pass one another or pass each other and then move away from one another again. The additional mixing arms sequentially pass a bottom section and a mixing arm past each other. Deposition or even sticking to the floor are excluded. Ideally, a bottom section and a mixing arm pass very close together, effectively draining the material from the bottom.

The fact that the mixing arms move along the floor past this in rapid succession, this sensitive area is better mixed and material accumulation in the floor area are efficiently avoided. The mix therefore does not have time to settle. The additional mixing arms have a boosting effect in terms of mixing efficiency and act as a kind of booster that enhances the mixing effect before the material is transported up through the helix. The mixing tool preferably terminates at a distance from the ground, so that abrasion is avoided. The mixing tool thus projects only from above into the interior of the container. The mixing arms can be guided at a distance from the bottom along, which may be preferably 3 mm to 20 mm. In contrast to other constructions, the construction of the mixing device is significantly simplified.

The Mischarmkonstruktion differs from the mixing spiral in particular in that the mixing arms do not extend helically around the central shaft. The mixing arms may extend radially outward or towards the container wall from the central shaft of the mixing tool. It is also possible that the mixing arms are offset from the central shaft, so that the extension of the mixing arm or its longitudinal axis spaced from the axis of rotation of the central shaft and this does not intersect.

It has proven to be advantageous if the container is designed so that it tapers conically down to the container bottom. Opposite the container bottom is the opening through which the mix can be introduced and through which the mixing tool is also introduced into the container so that it floats above the floor. The container may be connectable to a drive which rotates the container about its vertical axis. Ideally, the upper end of the conical bottom converges with the vertical axis of the container, which may also be the axis of rotation of the container. In cross section, the container bottom may at least partially have the shape of a triangle.

Preferably, the number of mixing arms is greater than the number of mixing helices. This ensures that the mix is whirled up before it is transported up through the coil. The mixing arms provide turbulence effects between the coils, which further improves the mixing result. In particular, the rapid sequence of the mixing arms, which can cause considerable turbulence, comes into play in comparison with a mixing spiral.

Preferably, the mixing arms converge in a common portion of the central shaft. They can be distributed in a cone-shaped plane corresponding to the cone-shaped plane around the central shaft, so that the mixing arms open obliquely, that is not perpendicular to the rotation shaft in the central shaft.

The section of the central shaft, which carries the mixing arms, can connect directly to the helix or mixing helix. Accordingly, the helix can extend in the axial direction of the mixing shaft up to the section which carries the mixing arms. An advantageous embodiment provides the helix in one to end the mixing arms. This means that at least one of the mixing arms is also designed as a holding arm.

To realize a mixer bell to easily remove the lid and mixing tool from the container, the mixing tool can be attached to the container lid. Preferably, this carries the drive for the mixing tool. The mixing tool can be mounted on the container lid and / or stored and extend from the direction of the upper container opening in the direction of the container bottom, without being supported on this. Due to the oblique arrangement of the mixing tool, the axis of rotation of the mixing tool moves in the direction of the container opening from the high and medium and / or rotational axis of the container. The mixing tool may be formed as a mixing screw and having one or more helically upwardly extending coils that transport the material from the lower end of the mixing vessel to the upper end of the mixing vessel. Ideally, the helix is designed such that it runs along the inner container wall or inner lateral surface of the container during rotation of the central shaft and thereby transports the mix upwards.

The mixing coil can be formed continuously in the axial direction of the central shaft. But it can also be divided into individual, spaced apart helical segments, similar to an interrupted helical flight.

The proposed mixing device is particularly suitable for mixing powdered, granular, pasty and / or liquid mix and can be used for example in dough production with great efficiency.

A particularly advantageous embodiment of the invention provides that the mixing tool is preferably at least six in the circumferential direction of the central shaft having uniformly distributed mixing arms. These can be attached to the central shaft as indicated above and extend in a star-shaped outward direction. In particular, adjacent mixing arms can each have the same angular distance from each other.

The mixing arms can be designed so that a flat bottom of the mixing arms on the ground is long. According to a further embodiment of the invention, the underside of the mixing arms is guided parallel to the conical surface of the container bottom or on a portion of the conical surface of the container bottom.

A further embodiment of the invention provides that the mixing arms have an inclined surface in the direction of rotation intended for operation. The inclined surface may be formed on a front portion of the mixing arms and, upon rotation of the central shaft, form the front or a frontal portion of the mixing arms. In order to generate a kind of planing effect, the mixing arms can have a profiled, in particular sharp, acute-angled edge, so that the frontal section of the mixing arms extends at an angle of less than 90 ° to the underside or to the top of the mixing arms. In particular, the settling of unfused and compacted masses on the container bottom is prevented. Other pointed shapes of the front are possible, whereby the mixing arms drive in the manner of a knife through the mix and can provide additional homogenization of the mix.

In order to achieve a higher mixing efficiency, the at least one helix may be arranged at a distance from the central shaft. Thus, the mixing tool can have at least one holding arm, which connects the lower end of the mixing spiral with the central shaft. For this purpose, holding arms, which extend in the radial direction from the central shaft to the outside, the helix hold. The holding arms can additionally contribute to the mixing. According to the invention, at least one mixing arm can be designed as a holding arm for the at least one helix, so that the helix terminates at a distance from the central shaft.

According to a further embodiment of the invention, the mixing tool, in particular the central shaft, a passage and at least one nozzle or the like for supplying gases, liquids or solids into the container. Thus, additional loosening air can be passed through the mixing tool and introduced into the mix. This ensures that the mixing components are thoroughly mixed. The loosening air can also generate additional turbulence, which further increases the mixing effect.

Advantageously, at least one of the mixing arms has at its outer end such a nozzle for supplying gases, liquids or solids into the container. The introduction of substances at the outermost point of the circular path, which describes the mixing arm, ensures that even difficult to reach areas of the container, in particular the outermost edge of the container bottom, are mixed.

The object underlying the invention is further achieved by a mixing tool for a mixing device for mixing mixed material. The features and embodiments described herein with respect to the mixing tool of the mixing apparatus apply equally to the mixing tool. Suitable mixing devices are in particular those which have a container rotatably mounted about a vertical axis, in which the mixing tool extends obliquely to the vertical axis of the container in the container, and in which the container bottom is conical.

Further developments, advantages and applications of the invention will become apparent from the following description of an embodiment and the drawings. All described and / or illustrated features alone or in any combination form the subject matter of the invention, regardless of their summary in the claims or their back references.

Fig. 1

in einer Schnittansicht eine Mischvorrichtung nach einer ersten Ausführungsform der Erfindung;

Fig. 2

in perspektiver Ansicht das Mischwerkzeug aus Figur 1; und

Fig. 3

in perspektiver Ansicht den unteren Abschnitt des Mischwerkzeugs aus Figur 2.

Show it:

Fig. 1

in a sectional view of a mixing device according to a first embodiment of the invention;

Fig. 2

in Perspective view the blending tool FIG. 1 ; and

Fig. 3

in perspective view, the bottom section of the blending tool FIG. 2 ,

FIG. 1 shows part of a mixing device 1 for mixing mixed material with a mixing container 2 with a high and middle axis 3. At the top of the container 2 has an opening 4, via which the container 2 can be filled with mix. Above the opening 4, a cover 5 which can be applied to the container 1 is arranged. By means of a lifting device 6, the lid 5 can be removed from the container 2 or positioned above it and / or on this. In the lid 5, the mixing tool 7 is rotatably mounted in a drive unit 8. The drive unit 8 rotatably drives the mixing tool 7 in operation about an axis of rotation 9 extending through the longitudinal axis of the mixing tool 7. The drive unit 8 is fixedly mounted on the lid 5, so that by lifting the lid 5 and the mixing tool 7 can be removed from the container 2. Such covers are referred to as a mixer bell.

The mixing tool 7 protrudes from the cover 5 into the interior 10 or mixing space of the container 2 and extends to the container bottom 11, where the mixing tool 7 ends at a distance from the container bottom 11, so that the mixing tool 7 is not supported on the container bottom 11. Furthermore, the mixing tool 7 is arranged obliquely to the vertical axis 3 of the container 2.

The mixing tool 7 carries two mixing helices 12, which extend helically around the rotation axis 9 at a distance from a central shaft 13 of the mixing tool 7 from the lower end of the mixing tool 7, which faces the container bottom 11, upward in the direction of the cover 5.

The container 2 comprises, starting from the upper opening 4, a downwardly extending cylindrical section 14 of a container wall 15. The cylindrical section 14 merges into a container section 16 tapering towards the container bottom 11, the container wall 15 being inclined in this section to the vertical axis 3 of the container 2 is inclined. The outer portions of the coils 12 are guided along the inside of the oblique tank wall portion 16 during the rotation of the mixing tool 7, and due to their helical shape, transport mix in the tank 2 upwardly from the tank bottom 11 and mix it.

The container bottom 11 is conical. Starting from corner regions or an edge region 17, in which the container wall 14 merges into the container bottom 11 and in which the lowest points of the container interior 10 is located, the container bottom 11 extends pointedly upwards. The container 2 is rotatably supported about the vertical axis 3 via a bearing 18. A drive 19 drives rollers which act on the underside of the container 2 and through which the container 2 for the mixing process is rotationally driven about its vertical axis or axis of rotation 3.

At the lower end of the mixing tool 7, the mixing tool 7 ends at a distance from the container bottom 11 in a portion having a number of mixing arms 20. The mixing arms 20 extend outwardly from the central shaft 13 substantially in the radial direction to the outside, but are arranged slightly offset from the axis of rotation 9. The arrangement of the mixing arms 20 on the central shaft 13 is also apparent from the perspective view in the FIG. 2 ,

The FIG. 2 shows the lower end of the mixing tool 7. At the distal end or at the container bottom directed end of the mixing tool 7 six mixing arms 20 are connected to the central shaft 13. The mixing arms 20 extend in a star shape from the mixing shaft 13 and each have the same angular distance to the adjacent mixing arm. Four of the mixing arms 20 have a freestanding end. As the FIG. 2 also shows, are mounted on the mixing tool 7 two mixing coils 12. The mixing helices 12 are arranged at a distance from the central shaft 13, wherein the mixing helices 12 are connected via retaining arms 21 with the central shaft 13. The holding arms 21 provide an additional mixing effect.

The FIG. 3 shows in an enlarged view the distal end of the mixing tool 7. Here, two substantially opposite mixing arms 20 are formed as a support arm for the lower end of the mixing helices 12, wherein the mixing helixes 12 end at the back of the support arms 20. This ensures improved absorption of the mix. The intended for the operation of rotation of the mixing tool 7 about the axis 9 is characterized by the arrow 22 drawn there. The frontal portion 23 of the mixing arms 20 has a profiled edge with an inclined surface 24. Thus, the mixing arm 20 cuts through the mix in the manner of a knife when the mixing tool 7 rotates. At the outermost end of the mixing arms 20, which are formed as holding arms, a nozzle 25 is arranged, which is connected to a not shown Air passage in the central shaft 13 is in communication, so that air or other gases or solids and the like can be introduced through the central shaft 13 and the mixing arm 20 from the nozzle 25 into the mix.

In operation, the mixing tool 7 rotates about the axis of rotation 9, while the container 2 rotates about its axis of rotation 3. As the FIG. 1 shows, in each case one of the mixing arms 20 passes a portion of the conical container bottom 11 at the in the FIG. 1 shown on the right side of the container bottom 11. The mixing arms are guided at a distance 26 to the surface of the container bottom 11. The number of mixing arms 20 is greater than the number of mixing spirals 12. Upon rotation of the mixing tool 7, strong turbulences and turbulence effects occur in the bottom area of the container 2. This effect prevents material accumulation in the bottom area. This is supported by the fact that the container bottom 11 has a conical shape, which ensures that the mix is directed towards the container wall 14. The nozzles 25 are directed into the corner region 17 of the container bottom 11. As a result, in this sensitive area material accumulations that would otherwise not be mixed up are whirled up and directed into the mixing area. The nozzles 25 thus provide additional turbulence, which significantly improves the mixing result.

LIST OF REFERENCE NUMBERS

1

mixing device

2

container

3

vertical axis

4

opening

5

cover

6

lifting device

7

mixing tool

8th

drive

9

axis of rotation

10

inner space

11

ground

12

mixing shaft

13

central shaft

14

cylindrical section

15

container wall

16

tapered container section

17

edge region

18

storage

19

drive

20

mixing arm

21

holding arm

22

Rotation direction of the central shaft

23

front section

24

sloping surface

25

jet

26

distance

Claims (10)

Mixing device (1) for mixing mixed material with
a container (2) rotatably mounted about a vertical axis (3) for receiving the mixture with an opening (4) and a mixing tool (7) extending through the opening (4) into the container (2) and rotatable about a rotation axis (9) with at least one mixing spiral (12) in order to transport the mix substantially along a container wall (15) of the container (2), wherein the axis of rotation (9) of the mixing tool (7) is oblique to the vertical axis (3) of the container (2 ) lies,
characterized in that the container bottom (11) is cone-shaped and that the mixing tool (7) at a container bottom (11) of the container (2) directed end carries a plurality of mixing arms (20) having at one end to a central shaft (13) of the mixing tool (7) are fixed and which are guided by rotation of the mixing tool (7) along the container bottom (11), wherein at least one of the mixing arms (20) on the side remote from the central shaft (13) has a free-standing end. Mixing device according to claim 1, characterized in that the number of mixing arms (20) is greater than the number of mixing spirals (12). Mixing device according to one of the preceding claims, characterized in that the mixing tool (7) at least six in the circumferential direction of the mixing tool (7) preferably uniformly distributed mixing arms (20). Mixing device according to one of the preceding claims, characterized in that the mixing tool (7) on a container lid (5) is fastened and that the container lid (5) carries a drive (8) for the mixing tool (7). Mixing device according to one of the preceding claims, characterized in that the mixing arms (20) in the direction of rotation (22) have an inclined surface (23). Mixing device according to one of the preceding claims, characterized in that the mixing arms (20) have a profiled, in particular sharp, acute-angled edge (24). Mixing device according to one of the preceding claims, characterized in that at least one mixing arm (20) is designed as a holding arm for the at least one mixing spiral (12). Mixing device according to one of the preceding claims, characterized in that the mixing tool (7) has a passage and at least one nozzle (25) or the like for supplying gases, liquids or solids into the container (2). Mixing device according to one of the preceding claims, characterized in that at least one of the mixing arms (20) has at its outer end a nozzle (25) for supplying gases, liquids or solids into the container (2). Mixing tool (7) for a mixing device (1) for mixing mixed material with a container (2) for receiving mixed material, wherein the mixing tool (7) at least one mixing coil (12) to the mix by rotation of the mixing tool (7) in Substantially up along a container wall (15) of the container (2),
characterized in that the mixing tool (7) at a to the container bottom (11) of the container (2) directed end carries a plurality of mixing arms (20) which are fixed at one end to a central shaft (13) of the mixing tool (7) and by Rotation of the mixing tool (7) are guided along the ground, wherein at least one of the mixing arms on the side facing away from the central shaft (13) has a free-standing end.

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