EP1925358B1 - Stirring device for producing a liquid mixture from at least two components, and the use of said stirring device - Google Patents

Description

The invention relates to a stirring tool for producing a liquid, optionally gaseous and / or fine-grained constituents containing mixture of at least two components according to the preamble of claim 1.

Mixing is a common practice in chemical engineering. Fluid mixing partners are usually mixed in fixed containers with rotating mixers arranged in the center of the container by forced flows. As a rule, a homogeneous distribution state of the mixing partners is sought. In the known mixing apparatus for fluids, for example stirred tank with a mechanically agitated disk stirrer, the achievable homogeneity of the mixture is often unsatisfactory, especially when higher-viscosity mixing partners have to be processed. The problem also arises when mixing, dispersing, emulsifying, stirring in various components, at least one of which is in a readily flowable state, in small containers, such as e.g. be used in a laboratory. The reason for this is the mixing energy that can not be supplied to a sufficient extent to the components to be mixed, so that only a correspondingly low displacement and shear action in the component mixture can be achieved.

From the DE 195 04 033 C2 is a motor-driven stirrer for mixing small amounts of liquids, emulsions, dispersions and dry or wet mixtures of fine-grained solids known in the end to a stirring shaft, a rotor disk is attached. The rotor disk consists of a circular disk disk and has flow-through openings which extend radially from the center of the disk to the vicinity of its outer periphery.

At the radial side edges of the flow-through upward and downward directed mixing blades are attached, via which a uniform wave flow is to be generated in the mix. However, the achievable with such a stirrer mixing quality does not satisfy in every way, since the channels formed by the mixing blades are open upwards or downwards and thus result in only limited positive flows. In addition, during the rotation of the stirrer co-rotation of the mixed material in the container practically unavoidable.

Furthermore, from the US 2004/022122 A1 a stirring tool for producing a mixture of at least two components known with a drivable agitator shaft and a rotor disk attached thereto end having a plurality of flow passages. These flow passages are made of symmetrically arranged axial bores and radial or tangential bores. Furthermore, from the US-A-4018598 another stirring tool is known, which has an end attached to a driven agitator shaft rotor disk, which is provided with holes. In addition, from the DE 1032 719 B1 a rotary dispenser known, in which the medium to be distributed is fed axially through a bore and is ejected through radial bores.

It is therefore an object of the invention to improve a stirrer specified in the preamble of claim 1 type so that with simple means a stronger local mixing of at least two components can be achieved and that particularly rapidly reproducible component mixtures can be obtained in improved mixing quality.

To solve this problem, the measures contained in the characterizing part of claim 1 are proposed.

In the agitating tool according to the invention, a plurality of, preferably 4-6, flow-through channels are provided in a circular or polygonal rotor disk attached to one end of a stirring shaft. These consist of aerodynamically interconnected axial bores and radial or tangential bores. When carrying out the mixing process, a negative pressure in the flow-through channels, which induces an additional vertical flow in the component mixture, arises as a result of the centrifugal forces generated by the rotor disk. There are sucked according to the number of flow channels partial streams from the mix, deflected into the axial bores and discharged from the radial or tangential bores, with a strong turbulence is generated. The resulting circulating flow leads to a particularly homogeneous and stable component mixture.

The flow channels according to the invention may have circular or polygonal cross-sections and optionally be conical. They are preferably arranged symmetrically to each other, such that on a pitch circle of the upper or lower end face of the rotor disk axial bores are introduced as far into the rotor disk until they intersect the radial or tangential bores. As a result, gases or solids can be distributed homogeneously in a component mixture in a particularly effective manner.

According to a further feature of the invention, the axial bores are through holes. In this way, when the rotor disk is arranged in the region of the phase boundary of the components to be mixed, they can be sucked in above and below the rotor disk, brought together in the radial or tangential bores and discharged in turbulent flow, wherein component partial streams are continuously sucked in. These forced flows result in an intensive mixing of components, in particular components of different consistency within short stirring times.

In order to avoid the formation of bubbles during the mixing of liquid components in a stirred vessel and adversely affecting the mixing result, in a further embodiment of the stirring tool according to the invention, the rotor disk consisting of a cylindrical section can be designed with a cone or frusto-conical shape on at least one end face of the cylinder section. In a polygonal rotor disk may be formed on at least one end face a corresponding polyhedral elevation. The axial bores extend in these embodiments of the rotor disc, of course, by the conical or polyhedral elevations.

The stirring tool according to the invention is suitable for example for mixing, emulsifying liquids, slightly pasty formulations and for dissolving or dispersing solids and / or gases in liquids, in particular for mixing chemically reactive components such as paint binders and hardeners, monomer solutions and catalysts, polymer solutions and active ingredients and adhesive formulations.

The invention is shown schematically in the drawings and explained in more detail below.

Fig. 1

eine Ausführungsform des Rührwerkzeuges mit 4 Durchströmkanälen in perspektivischer Darstellung

Fig. 2

einen Längsschnitt des Rührwerkzeuges entsprechend Fig. 1

Fig. 3

eine Draufsicht auf das Rührwerkzeug entsprechend Fig. 1

Fig. 4

eine Seitenansicht einer weiteren Ausführungsform des Rührwerkzeuges

Fig. 5

eine Draufsicht des Rührwerkzeuges gemäß Fig. 4

Fig. 6

eine Seitenansicht eines Rührwerkzeuges mit sechseckiger Rotorscheibe und

Fig. 7

das Rührwerkzeug nach Fig. 6 in der Draufsicht.

It shows

Fig. 1

an embodiment of the stirring tool with 4 flow channels in a perspective view

Fig. 2

a longitudinal section of the stirring tool accordingly Fig. 1

Fig. 3

a plan view of the stirring tool accordingly Fig. 1

Fig. 4

a side view of another embodiment of the stirring tool

Fig. 5

a plan view of the stirring tool according to Fig. 4

Fig. 6

a side view of a stirring tool with hexagonal rotor disk and

Fig. 7

the stirrer after Fig. 6 in the plan view.

Essentially, the stirring tool is after the FIGS. 1 to 3 from a drivable agitator shaft (1) and a rotor disk (2) fastened at the end to the agitator shaft in the form of a cylinder section. The rotor disk contains four symmetrically arranged through-flow channels, which are formed from four axial bores (3) and four radial bores (4). In each case an axial bore is connected to a radial bore. The radial distance of the bores (3) from the agitator shaft (1) can be varied depending on the diameter of the rotor disk and the flow-through channels. With (5) conical protrusions are designated on the end faces of the cylinder portion of the rotor disk.

To produce a homogeneous mixture, the stirring tool is immersed in the components contained in a stationary stirring container and set in a rotary motion. The resulting centrifugal forces cause a component delivery through the radial bores (4) while the axial bores (3) continuously flow component flows from above and below. In the radial Drilling as well as the leakage of the components or of the component mixture from the flow-through channels, a mixing of the components or the emerging from the flow passages component flow with the Rührbehälterinhalt. By repeatedly conveying the mixed material through the flow channels particularly homogeneous mixtures are obtained. Flow-influencing bodies in the flow-through channels (not shown in the drawings) can increase the mixing effect.

In the embodiment of the stirring tool according to the FIGS. 4 and 5 extend the axial holes (3) from below only as far in the circular rotor disk (2) until they cut the center mounted in the cylinder section holes (4), so that only from below components or mixture is sucked. Such a construction is particularly suitable when fine-grained solid is mixed into a liquid or when the entry of gases into the liquid should be avoided. For a particularly gentle mixing of components, it has proved expedient to arrange the bores (4) not radially but tangentially, ie at an angle of approximately 30 to approximately 45 degrees to the radial opposite to the direction of rotation of the stirring tool.

In general, the rotor disk (2) is circular. But it can also consist of a polygon, as in the 6 and 7 is shown.

Claims (5)

1. Stirring tool for producing from at least two components a mixture which is liquid, possibly gaseous and/or contains fine-grained constituent parts, having a drivable stirring shaft (1) and a rotor disc (2), which is fastened at the end of the shaft and has a plurality of throughflow channels, characterized in that the throughflow channels comprise symmetrically arranged axial bores (3) and radial or tangential bores (4), wherein an axial bore in each case intersects a radial or a tangential bore.
2. Stirring tool according to Claim 1, characterized in that the axial bores (3) are through-passage bores.
3. Stirring tool according to Claim 1, characterized in that the rotor disc (2) comprises a cylinder portion, and at least one end surface of the cylinder portion is conical or frustoconical.
4. Stirring tool according to Claim 1, characterized in that the rotor disc (2) is polygonal, and has a corresponding polyhedral elevation on at least one end surface.
5. Use of the stirring tool according to one or more of Claims 1 to 4 for mixing chemically reactive components.

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