Mixing device

Abstract

The invention relates to a mixing device (10) comprising a mixing container (14) and a mixing tool arranged in the mixing container, wherein a mixing material receiving volume (18) of the mixing container is delimited by a conical container wall (20) and by a cover (22), the mixing tool comprising a helical mixing arm which has a helical conveying surface, which can be rotatably driven about a central vertical axis (24) of the mixing container, at least one stationary interfering surface being arranged in the mixing container, which, together with at least one counter-surface of the mixing arm, delimits a mixing gap for shear loading of the mixing material.

Description

[0001] DREISS PATENT ATTORNEYS > 09.01.2026

[0002] 60010383WO 704130.4

[0003] Hüttlin GmbH

[0004] Hohe-Flum-Straße 42

[0005] 79650 Schopfheim

[0006] Mixing device

[0007] The invention relates to a mixing device comprising a mixing container and a mixing tool arranged in the mixing container, wherein a mixing material intake volume of the mixing container is limited by a conical container wall and by a lid, wherein the mixing tool has an egg-shaped mixing arm with an egg-shaped conveying surface, which can be rotatably driven about a central vertical axis of the mixing container.

[0008] From DE 10 2021 129838 A1, a mixing device of the generic type is known, which is intended to be cost-effective to manufacture and allows for particularly gentle mixing of the mixture. However, it has been found that it takes a very long time to achieve a high degree of homogeneity for low-dose active ingredient mixtures, which is particularly necessary for the direct tableting of a pharmaceutical mixture.

[0009] Based on this, the present invention aims to provide a mixing device which allows for efficient and homogeneous mixing even with low doses of active ingredients.

[0010] This problem is solved in a mixing device of the type mentioned above by arranging at least one stationary disturbance surface in the mixing container, which together with at least one counter surface of the mixing arm limits a mixing gap for shearing stress on the mixture.

[0011] According to the invention, the mixing device comprises an additional mixing element in the form of a stationary interference surface. The interference surface is immovable and, together with a counter surface of the movable mixing arm, defines a mixing gap that always arises when the counter surface is located adjacent to the interference surface during rotation about the central vertical axis. Preferably, the interference surface extends along a circumference about the central vertical axis over a comparatively small angle, for example, a maximum of 45°.

[0012] The mixing gap according to the invention enables the provision of high shear forces, which contribute to rapid and homogeneous mixing of the mixture. The mixing gap and the high shear stress on the mixture also contribute to the breakdown of unwanted agglomerates in the mixture.

[0013] It is preferred if the mixing gap has a gap height of no more than 4 mm, particularly no more than 3 mm. Preferred gap heights are in the range between 1 mm and 3 mm.

[0014] It is further preferred if the at least one disturbance surface is spaced away from both the container wall and the central vertical axis. This allows shear forces to be introduced into the mixture in an area that is unaffected by mixture flows at the vertical axis and at the container wall.

[0015] It is further preferred if the at least one disturbance surface is spaced away from both the lid and the bottom of the mixing container. In this way, shear forces can be introduced into the mixture in a region of the mixing container that is spaced away from the lid and is unaffected by the flow of the mixture at the bottom of the mixing container.

[0016] Preferably, the interference surface is arranged on an interference surface holder, which allows for easy positioning of the interference surface in the mixing container. The interference surface holder can, for example, have a holding arm that extends parallel to the vertical axis of the mixing container.

[0017] In particular, it is preferred if the interference surface holder is attached to the lid, thereby allowing the installation space of the mixing container to be used essentially above the mixing arm.

[0018] It is further preferred that several offset interference surfaces are arranged on the interference surface holder, thereby multiplying the shear stress on the mixture. In particular, an interference surface holder has at least one interference surface, preferably two, and more preferably three or four interference surfaces.

[0019] In particular, the mixing device comprises two, three, or four interference surface holders. It is possible that at least one of the opposing surfaces is an integral part of the conveying surface, which allows for the use of a particularly simple mixing arm design.

[0020] It is possible that at least one counter surface adjoins the conveying surface, which also allows for the use of a particularly simple mixing arm.

[0021] The at least one counter surface is preferably inclined relative to the conveying surface, so that a comparatively large counter surface can be provided. This applies in particular if the at least one counter surface is part of a material recess in the mixing arm. Preferably, the material recess extends downwards from the conveying surface along the vertical axis, so that the mixture can fall from the conveying surface over the material recess into the lower part of the mixing container, from where it can be transported upwards again via the conveying surface.

[0022] The conveying surface has a width measured radially with respect to the central vertical axis, preferably being wider in a central region than in a lower region and / or an upper region. This allows the conveying effect of the surface to be increased from the bottom up to a central region of the mixing container and then reduced again towards an upper region. This measure also contributes to thorough mixing.

[0023] It is further preferred that the mixing arm has a plurality of offset counter-surfaces, thereby enabling shearing stress on the mixture in several areas along the mixing arm.

[0024] It is further preferred that the mixing tool has a plurality of mixing arms, which are preferably arranged regularly distributed along a circumference around the central vertical axis. In particular, the mixing tool has two, three, or four mixing arms.

[0025] Furthermore, it is preferred if the mixing arms are connected to each other at a lower end relative to the central vertical axis and / or if the mixing arms are freestanding and not connected to each other at an upper end relative to the central vertical axis. Connecting the mixing arms at a lower end contributes to improved stability of the mixing tool. A freestanding arrangement of the upper ends of the mixing arms simplifies the arrangement of a previously discussed interference surface holder. This holder can be arranged, in particular, between the central vertical axis and the freestanding end of a mixing arm, viewed radially. Further features and advantages of the invention are the subject of the following description of a preferred embodiment.

[0026] The drawing shows:

[0027] Fig. 1 shows a perspective view of an embodiment of a mixing device;

[0028] Fig. 2 shows a side view of a mixing tool of the mixing device according to Fig. 1; and

[0029] Fig. 3 shows a top view of the mixing tool of the mixing device according to Fig. 1.

[0030] One embodiment of a mixing device is designated in the drawing by reference numeral 10, see Figure 1. The mixing device 10 is placed on a surface 12, in particular a horizontal one, and comprises a mixing container 14 in which a mixing tool 16 (shown in Figures 2 and 3) is arranged.

[0031] The mixing container 14 provides a mixing material intake volume 18, which is limited by a conical container wall 20 and a lid 22.

[0032] The mixing container 14 has a central vertical axis 24 around which the mixing tool 16 can be rotated by means of a rotary drive 26.

[0033] For filling the mixing container 14 with various components of a mixture, the mixing container 14 has releasably closable inlets 28, which are arranged, for example, on the lid 22.

[0034] An outlet 32 ​​for the mixture is arranged at a lower end 30 of the mixing container 14. The outlet 32 ​​is switchable and comprises, for example, a ball segment valve 34, which is arranged in the region of a bottom 36 of the mixing container 14 (shown schematically in Figure 2), preferably complementary to a spherical segment surface 86 at a lower end of the mixing container 14.

[0035] The mixing tool 16 has two egg-shaped mixing arms 38 and 40, which are aligned relative to each other at an angular distance of 180° with respect to the central vertical axis 24. The mixing arms 38 and 40 are connected to each other in a lower section 30.

[0036] The mixing arms 38 and 40 are connected via radial arms 42 and 44 to a central mandrel 46 of the mixing tool 16. The central mandrel 46 runs collinearly to the central vertical axis 24. Each of the mixing arms 38, 40 is egg-shaped and has an egg-shaped conveying surface 48, 50. The conveying surfaces 48, 50 point upwards and serve to convey the mixture from the lower area 30 through a middle area 52 to an upper area 54.

[0037] Preferably, the width 56 of the conveying surface 48, 50, measured radially with respect to the vertical axis 24, is greater than in the lower region 30 and / or than in an upper region 54.

[0038] Starting from the conveying surfaces 48, 50, the mixing arms 38, 40 have pocket-shaped material recesses 58 extending towards the lower end 30 (see Figure 3).

[0039] The material recesses 58 have inclined counter-surfaces 60 facing the respective conveying surfaces 48, 50. For example, each mixing arm 38, 40 has three counter-surfaces 60 arranged offset from one another along the curved path of the mixing arm 38, 40.

[0040] The upper ends 62, 64 of the mixing arms 38, 40 are freestanding, i.e., not connected to each other. Furthermore, the ends 62, 64 are spaced parallel to the vertical axis 24 from an underside 66 of the lid 22, which is schematically indicated in Figure 2. A distance 68 is, for example, between 10% and 20% of the total height of the mixing container 14 (corresponding to the distance between the base 36 and the underside 66 of the lid 22).

[0041] The mixing device 10 further comprises a plurality of interference surface holders 70 with vertically extending retaining arms 72, which are fixed at an upper end 74 to the lid 22 of the mixing container 14. The retaining arms 72 are arranged distributed along a circumference around the vertical axis 24, in particular in a regularly distributed manner.

[0042] The retaining arms 72 are connected at a lower end 76 to a rod-shaped support 78, from which at least one obstruction element 80 projects. For example, three obstruction elements 80 are provided along the course of the support 78, offset from one another.

[0043] The interference elements 80 are designed, for example, as flat elements and have a interference surface 82 pointing downwards with respect to the vertical axis 24. The interference surfaces 82 are stationary, i.e., immovable. Each interference surface 82, together with a movable counter surface 60 of the mixing tool 16, defines a mixing gap 84 in which the mixture is subjected to a high shear stress.

[0044] The mixing tool 16 preferably rotates around the vertical axis 24 at a maximum of 500 revolutions per minute, in particular at 200 to 300 revolutions per minute.

Claims

Patent claims 1. Mixing device (10) comprising a mixing container (14) and a mixing tool (16) arranged in the mixing container (14), wherein a mixing material receiving volume (18) of the mixing container (14) is limited by a conical container wall (20) and by a lid (22), wherein the mixing tool (16) has an egg-shaped mixing arm (38, 40) with an egg-shaped conveying surface (48, 50) which is rotatably driven about a central vertical axis (24) of the mixing container (14), characterized in that at least one stationary disturbance surface (82) is arranged in the mixing container (14), which together with at least one counter surface (60) of the mixing arm (38, 40) limits a mixing gap (84) for shearing the mixing material.

2. Mixing device (10) according to claim 1, characterized in that the mixing gap (84) has a gap height of a maximum of 4 mm, in particular a maximum of 3 mm.

3. Mixing device (10) according to one of the preceding claims, characterized in that the at least one interference surface (82) is spaced apart from both the container wall (20) and the central vertical axis (24).

4. Mixing device (10) according to one of the preceding claims, characterized in that the at least one interference surface (82) is spaced apart from both the lid (22) and a bottom (36) of the mixing container (14).

5. Mixing device (10) according to one of the preceding claims, characterized in that the at least one interference surface (82) is arranged on an interference surface holder (70).

6. Mixing device (10) according to claim 5, characterized in that the interference surface holder (70) is attached to the lid (22).

7. Mixing device (10) according to claim 5 or 6, characterized in that several interference surfaces (82) offset from one another are arranged on the interference surface holder (70).

8. Mixing device (10) according to one of the preceding claims, characterized in that the at least one counter surface (60) is an integral part of the conveying surface (48, 50).

9. Mixing device (10) according to one of the preceding claims, characterized in that the at least one counter surface (60) adjoins the conveying surface (48, 50).

610. Mixing device (10) according to one of the preceding claims, characterized in that the at least one counter surface (60) is inclined relative to the conveying surface (48, 50).

11. Mixing device (10) according to one of the preceding claims, characterized in that the at least one counter surface (60) is part of a material recess (58) of the mixing arm (38, 40).

12. Mixing device (10) according to one of the preceding claims, characterized in that the conveying surface (48, 50) has a width (56) measured in the radial direction with respect to the central vertical axis (24), wherein the width in a middle region (52) of the conveying surface (48, 50) is greater than in a lower region (30) of the conveying surface (48, 50) and / or than in an upper region (54) of the conveying surface (48, 50).

13. Mixing device (10) according to one of the preceding claims, characterized in that the mixing arm (38, 40) has a plurality of offset counter surfaces (60).

14. Mixing device (10) according to one of the preceding claims, characterized in that the mixing tool (16) has a plurality of mixing arms (38, 40) which are preferably arranged regularly distributed along a circumference around the central vertical axis (24).

15. Mixing device (10) according to claim 14, characterized in that the mixing arms (38, 40) are connected to each other at a lower end (30) with respect to the central vertical axis (24) and / or that the mixing arms (38, 40) are designed to be freestanding and not connected to each other at an upper end (54) with respect to the central vertical axis (24).

Images